// SPDX-License-Identifier: GPL-2.0 /* * Shared application/kernel submission and completion ring pairs, for * supporting fast/efficient IO. * * A note on the read/write ordering memory barriers that are matched between * the application and kernel side. * * After the application reads the CQ ring tail, it must use an * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses * before writing the tail (using smp_load_acquire to read the tail will * do). It also needs a smp_mb() before updating CQ head (ordering the * entry load(s) with the head store), pairing with an implicit barrier * through a control-dependency in io_get_cqe (smp_store_release to * store head will do). Failure to do so could lead to reading invalid * CQ entries. * * Likewise, the application must use an appropriate smp_wmb() before * writing the SQ tail (ordering SQ entry stores with the tail store), * which pairs with smp_load_acquire in io_get_sqring (smp_store_release * to store the tail will do). And it needs a barrier ordering the SQ * head load before writing new SQ entries (smp_load_acquire to read * head will do). * * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after* * updating the SQ tail; a full memory barrier smp_mb() is needed * between. * * Also see the examples in the liburing library: * * git://git.kernel.dk/liburing * * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens * from data shared between the kernel and application. This is done both * for ordering purposes, but also to ensure that once a value is loaded from * data that the application could potentially modify, it remains stable. * * Copyright (C) 2018-2019 Jens Axboe * Copyright (c) 2018-2019 Christoph Hellwig */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include #include #include "internal.h" #include "io-wq.h" #define IORING_MAX_ENTRIES 32768 #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES) #define IORING_SQPOLL_CAP_ENTRIES_VALUE 8 /* only define max */ #define IORING_MAX_FIXED_FILES (1U << 15) #define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \ IORING_REGISTER_LAST + IORING_OP_LAST) #define IO_RSRC_TAG_TABLE_SHIFT (PAGE_SHIFT - 3) #define IO_RSRC_TAG_TABLE_MAX (1U << IO_RSRC_TAG_TABLE_SHIFT) #define IO_RSRC_TAG_TABLE_MASK (IO_RSRC_TAG_TABLE_MAX - 1) #define IORING_MAX_REG_BUFFERS (1U << 14) #define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \ IOSQE_IO_HARDLINK | IOSQE_ASYNC) #define SQE_VALID_FLAGS (SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \ IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS) #define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \ REQ_F_POLLED | REQ_F_CREDS | REQ_F_ASYNC_DATA) #define IO_TCTX_REFS_CACHE_NR (1U << 10) struct io_uring { u32 head ____cacheline_aligned_in_smp; u32 tail ____cacheline_aligned_in_smp; }; /* * This data is shared with the application through the mmap at offsets * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING. * * The offsets to the member fields are published through struct * io_sqring_offsets when calling io_uring_setup. */ struct io_rings { /* * Head and tail offsets into the ring; the offsets need to be * masked to get valid indices. * * The kernel controls head of the sq ring and the tail of the cq ring, * and the application controls tail of the sq ring and the head of the * cq ring. */ struct io_uring sq, cq; /* * Bitmasks to apply to head and tail offsets (constant, equals * ring_entries - 1) */ u32 sq_ring_mask, cq_ring_mask; /* Ring sizes (constant, power of 2) */ u32 sq_ring_entries, cq_ring_entries; /* * Number of invalid entries dropped by the kernel due to * invalid index stored in array * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * After a new SQ head value was read by the application this * counter includes all submissions that were dropped reaching * the new SQ head (and possibly more). */ u32 sq_dropped; /* * Runtime SQ flags * * Written by the kernel, shouldn't be modified by the * application. * * The application needs a full memory barrier before checking * for IORING_SQ_NEED_WAKEUP after updating the sq tail. */ u32 sq_flags; /* * Runtime CQ flags * * Written by the application, shouldn't be modified by the * kernel. */ u32 cq_flags; /* * Number of completion events lost because the queue was full; * this should be avoided by the application by making sure * there are not more requests pending than there is space in * the completion queue. * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * As completion events come in out of order this counter is not * ordered with any other data. */ u32 cq_overflow; /* * Ring buffer of completion events. * * The kernel writes completion events fresh every time they are * produced, so the application is allowed to modify pending * entries. */ struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp; }; enum io_uring_cmd_flags { IO_URING_F_COMPLETE_DEFER = 1, IO_URING_F_UNLOCKED = 2, /* int's last bit, sign checks are usually faster than a bit test */ IO_URING_F_NONBLOCK = INT_MIN, }; struct io_mapped_ubuf { u64 ubuf; u64 ubuf_end; unsigned int nr_bvecs; unsigned long acct_pages; struct bio_vec bvec[]; }; struct io_ring_ctx; struct io_overflow_cqe { struct io_uring_cqe cqe; struct list_head list; }; struct io_fixed_file { /* file * with additional FFS_* flags */ unsigned long file_ptr; }; struct io_rsrc_put { struct list_head list; u64 tag; union { void *rsrc; struct file *file; struct io_mapped_ubuf *buf; }; }; struct io_file_table { struct io_fixed_file *files; }; struct io_rsrc_node { struct percpu_ref refs; struct list_head node; struct list_head rsrc_list; struct io_rsrc_data *rsrc_data; struct llist_node llist; bool done; }; typedef void (rsrc_put_fn)(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); struct io_rsrc_data { struct io_ring_ctx *ctx; u64 **tags; unsigned int nr; rsrc_put_fn *do_put; atomic_t refs; struct completion done; bool quiesce; }; struct io_buffer_list { struct list_head list; struct list_head buf_list; __u16 bgid; }; struct io_buffer { struct list_head list; __u64 addr; __u32 len; __u16 bid; __u16 bgid; }; struct io_restriction { DECLARE_BITMAP(register_op, IORING_REGISTER_LAST); DECLARE_BITMAP(sqe_op, IORING_OP_LAST); u8 sqe_flags_allowed; u8 sqe_flags_required; bool registered; }; enum { IO_SQ_THREAD_SHOULD_STOP = 0, IO_SQ_THREAD_SHOULD_PARK, }; struct io_sq_data { refcount_t refs; atomic_t park_pending; struct mutex lock; /* ctx's that are using this sqd */ struct list_head ctx_list; struct task_struct *thread; struct wait_queue_head wait; unsigned sq_thread_idle; int sq_cpu; pid_t task_pid; pid_t task_tgid; unsigned long state; struct completion exited; }; #define IO_COMPL_BATCH 32 #define IO_REQ_CACHE_SIZE 32 #define IO_REQ_ALLOC_BATCH 8 struct io_submit_link { struct io_kiocb *head; struct io_kiocb *last; }; struct io_submit_state { /* inline/task_work completion list, under ->uring_lock */ struct io_wq_work_node free_list; /* batch completion logic */ struct io_wq_work_list compl_reqs; struct io_submit_link link; bool plug_started; bool need_plug; bool flush_cqes; unsigned short submit_nr; struct blk_plug plug; }; struct io_ev_fd { struct eventfd_ctx *cq_ev_fd; unsigned int eventfd_async: 1; struct rcu_head rcu; }; #define IO_BUFFERS_HASH_BITS 5 struct io_ring_ctx { /* const or read-mostly hot data */ struct { struct percpu_ref refs; struct io_rings *rings; unsigned int flags; unsigned int compat: 1; unsigned int drain_next: 1; unsigned int restricted: 1; unsigned int off_timeout_used: 1; unsigned int drain_active: 1; unsigned int drain_disabled: 1; unsigned int has_evfd: 1; } ____cacheline_aligned_in_smp; /* submission data */ struct { struct mutex uring_lock; /* * Ring buffer of indices into array of io_uring_sqe, which is * mmapped by the application using the IORING_OFF_SQES offset. * * This indirection could e.g. be used to assign fixed * io_uring_sqe entries to operations and only submit them to * the queue when needed. * * The kernel modifies neither the indices array nor the entries * array. */ u32 *sq_array; struct io_uring_sqe *sq_sqes; unsigned cached_sq_head; unsigned sq_entries; struct list_head defer_list; /* * Fixed resources fast path, should be accessed only under * uring_lock, and updated through io_uring_register(2) */ struct io_rsrc_node *rsrc_node; int rsrc_cached_refs; struct io_file_table file_table; unsigned nr_user_files; unsigned nr_user_bufs; struct io_mapped_ubuf **user_bufs; struct io_submit_state submit_state; struct list_head timeout_list; struct list_head ltimeout_list; struct list_head cq_overflow_list; struct list_head *io_buffers; struct list_head io_buffers_cache; struct list_head apoll_cache; struct xarray personalities; u32 pers_next; unsigned sq_thread_idle; } ____cacheline_aligned_in_smp; /* IRQ completion list, under ->completion_lock */ struct io_wq_work_list locked_free_list; unsigned int locked_free_nr; const struct cred *sq_creds; /* cred used for __io_sq_thread() */ struct io_sq_data *sq_data; /* if using sq thread polling */ struct wait_queue_head sqo_sq_wait; struct list_head sqd_list; unsigned long check_cq_overflow; struct { unsigned cached_cq_tail; unsigned cq_entries; struct io_ev_fd __rcu *io_ev_fd; struct wait_queue_head cq_wait; unsigned cq_extra; atomic_t cq_timeouts; unsigned cq_last_tm_flush; } ____cacheline_aligned_in_smp; struct { spinlock_t completion_lock; spinlock_t timeout_lock; /* * ->iopoll_list is protected by the ctx->uring_lock for * io_uring instances that don't use IORING_SETUP_SQPOLL. * For SQPOLL, only the single threaded io_sq_thread() will * manipulate the list, hence no extra locking is needed there. */ struct io_wq_work_list iopoll_list; struct hlist_head *cancel_hash; unsigned cancel_hash_bits; bool poll_multi_queue; struct list_head io_buffers_comp; } ____cacheline_aligned_in_smp; struct io_restriction restrictions; /* slow path rsrc auxilary data, used by update/register */ struct { struct io_rsrc_node *rsrc_backup_node; struct io_mapped_ubuf *dummy_ubuf; struct io_rsrc_data *file_data; struct io_rsrc_data *buf_data; struct delayed_work rsrc_put_work; struct llist_head rsrc_put_llist; struct list_head rsrc_ref_list; spinlock_t rsrc_ref_lock; struct list_head io_buffers_pages; }; /* Keep this last, we don't need it for the fast path */ struct { #if defined(CONFIG_UNIX) struct socket *ring_sock; #endif /* hashed buffered write serialization */ struct io_wq_hash *hash_map; /* Only used for accounting purposes */ struct user_struct *user; struct mm_struct *mm_account; /* ctx exit and cancelation */ struct llist_head fallback_llist; struct delayed_work fallback_work; struct work_struct exit_work; struct list_head tctx_list; struct completion ref_comp; u32 iowq_limits[2]; bool iowq_limits_set; }; }; /* * Arbitrary limit, can be raised if need be */ #define IO_RINGFD_REG_MAX 16 struct io_uring_task { /* submission side */ int cached_refs; struct xarray xa; struct wait_queue_head wait; const struct io_ring_ctx *last; struct io_wq *io_wq; struct percpu_counter inflight; atomic_t in_idle; spinlock_t task_lock; struct io_wq_work_list task_list; struct io_wq_work_list prior_task_list; struct callback_head task_work; struct file **registered_rings; bool task_running; }; /* * First field must be the file pointer in all the * iocb unions! See also 'struct kiocb' in */ struct io_poll_iocb { struct file *file; struct wait_queue_head *head; __poll_t events; struct wait_queue_entry wait; }; struct io_poll_update { struct file *file; u64 old_user_data; u64 new_user_data; __poll_t events; bool update_events; bool update_user_data; }; struct io_close { struct file *file; int fd; u32 file_slot; }; struct io_timeout_data { struct io_kiocb *req; struct hrtimer timer; struct timespec64 ts; enum hrtimer_mode mode; u32 flags; }; struct io_accept { struct file *file; struct sockaddr __user *addr; int __user *addr_len; int flags; u32 file_slot; unsigned long nofile; }; struct io_sync { struct file *file; loff_t len; loff_t off; int flags; int mode; }; struct io_cancel { struct file *file; u64 addr; }; struct io_timeout { struct file *file; u32 off; u32 target_seq; struct list_head list; /* head of the link, used by linked timeouts only */ struct io_kiocb *head; /* for linked completions */ struct io_kiocb *prev; }; struct io_timeout_rem { struct file *file; u64 addr; /* timeout update */ struct timespec64 ts; u32 flags; bool ltimeout; }; struct io_rw { /* NOTE: kiocb has the file as the first member, so don't do it here */ struct kiocb kiocb; u64 addr; u32 len; u32 flags; }; struct io_connect { struct file *file; struct sockaddr __user *addr; int addr_len; }; struct io_sr_msg { struct file *file; union { struct compat_msghdr __user *umsg_compat; struct user_msghdr __user *umsg; void __user *buf; }; int msg_flags; int bgid; size_t len; size_t done_io; }; struct io_open { struct file *file; int dfd; u32 file_slot; struct filename *filename; struct open_how how; unsigned long nofile; }; struct io_rsrc_update { struct file *file; u64 arg; u32 nr_args; u32 offset; }; struct io_fadvise { struct file *file; u64 offset; u32 len; u32 advice; }; struct io_madvise { struct file *file; u64 addr; u32 len; u32 advice; }; struct io_epoll { struct file *file; int epfd; int op; int fd; struct epoll_event event; }; struct io_splice { struct file *file_out; loff_t off_out; loff_t off_in; u64 len; int splice_fd_in; unsigned int flags; }; struct io_provide_buf { struct file *file; __u64 addr; __u32 len; __u32 bgid; __u16 nbufs; __u16 bid; }; struct io_statx { struct file *file; int dfd; unsigned int mask; unsigned int flags; struct filename *filename; struct statx __user *buffer; }; struct io_shutdown { struct file *file; int how; }; struct io_rename { struct file *file; int old_dfd; int new_dfd; struct filename *oldpath; struct filename *newpath; int flags; }; struct io_unlink { struct file *file; int dfd; int flags; struct filename *filename; }; struct io_mkdir { struct file *file; int dfd; umode_t mode; struct filename *filename; }; struct io_symlink { struct file *file; int new_dfd; struct filename *oldpath; struct filename *newpath; }; struct io_hardlink { struct file *file; int old_dfd; int new_dfd; struct filename *oldpath; struct filename *newpath; int flags; }; struct io_msg { struct file *file; u64 user_data; u32 len; }; struct io_async_connect { struct sockaddr_storage address; }; struct io_async_msghdr { struct iovec fast_iov[UIO_FASTIOV]; /* points to an allocated iov, if NULL we use fast_iov instead */ struct iovec *free_iov; struct sockaddr __user *uaddr; struct msghdr msg; struct sockaddr_storage addr; }; struct io_rw_state { struct iov_iter iter; struct iov_iter_state iter_state; struct iovec fast_iov[UIO_FASTIOV]; }; struct io_async_rw { struct io_rw_state s; const struct iovec *free_iovec; size_t bytes_done; struct wait_page_queue wpq; }; enum { REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT, REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT, REQ_F_LINK_BIT = IOSQE_IO_LINK_BIT, REQ_F_HARDLINK_BIT = IOSQE_IO_HARDLINK_BIT, REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT, REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT, REQ_F_CQE_SKIP_BIT = IOSQE_CQE_SKIP_SUCCESS_BIT, /* first byte is taken by user flags, shift it to not overlap */ REQ_F_FAIL_BIT = 8, REQ_F_INFLIGHT_BIT, REQ_F_CUR_POS_BIT, REQ_F_NOWAIT_BIT, REQ_F_LINK_TIMEOUT_BIT, REQ_F_NEED_CLEANUP_BIT, REQ_F_POLLED_BIT, REQ_F_BUFFER_SELECTED_BIT, REQ_F_COMPLETE_INLINE_BIT, REQ_F_REISSUE_BIT, REQ_F_CREDS_BIT, REQ_F_REFCOUNT_BIT, REQ_F_ARM_LTIMEOUT_BIT, REQ_F_ASYNC_DATA_BIT, REQ_F_SKIP_LINK_CQES_BIT, REQ_F_SINGLE_POLL_BIT, REQ_F_DOUBLE_POLL_BIT, REQ_F_PARTIAL_IO_BIT, /* keep async read/write and isreg together and in order */ REQ_F_SUPPORT_NOWAIT_BIT, REQ_F_ISREG_BIT, /* not a real bit, just to check we're not overflowing the space */ __REQ_F_LAST_BIT, }; enum { /* ctx owns file */ REQ_F_FIXED_FILE = BIT(REQ_F_FIXED_FILE_BIT), /* drain existing IO first */ REQ_F_IO_DRAIN = BIT(REQ_F_IO_DRAIN_BIT), /* linked sqes */ REQ_F_LINK = BIT(REQ_F_LINK_BIT), /* doesn't sever on completion < 0 */ REQ_F_HARDLINK = BIT(REQ_F_HARDLINK_BIT), /* IOSQE_ASYNC */ REQ_F_FORCE_ASYNC = BIT(REQ_F_FORCE_ASYNC_BIT), /* IOSQE_BUFFER_SELECT */ REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT), /* IOSQE_CQE_SKIP_SUCCESS */ REQ_F_CQE_SKIP = BIT(REQ_F_CQE_SKIP_BIT), /* fail rest of links */ REQ_F_FAIL = BIT(REQ_F_FAIL_BIT), /* on inflight list, should be cancelled and waited on exit reliably */ REQ_F_INFLIGHT = BIT(REQ_F_INFLIGHT_BIT), /* read/write uses file position */ REQ_F_CUR_POS = BIT(REQ_F_CUR_POS_BIT), /* must not punt to workers */ REQ_F_NOWAIT = BIT(REQ_F_NOWAIT_BIT), /* has or had linked timeout */ REQ_F_LINK_TIMEOUT = BIT(REQ_F_LINK_TIMEOUT_BIT), /* needs cleanup */ REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT), /* already went through poll handler */ REQ_F_POLLED = BIT(REQ_F_POLLED_BIT), /* buffer already selected */ REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT), /* completion is deferred through io_comp_state */ REQ_F_COMPLETE_INLINE = BIT(REQ_F_COMPLETE_INLINE_BIT), /* caller should reissue async */ REQ_F_REISSUE = BIT(REQ_F_REISSUE_BIT), /* supports async reads/writes */ REQ_F_SUPPORT_NOWAIT = BIT(REQ_F_SUPPORT_NOWAIT_BIT), /* regular file */ REQ_F_ISREG = BIT(REQ_F_ISREG_BIT), /* has creds assigned */ REQ_F_CREDS = BIT(REQ_F_CREDS_BIT), /* skip refcounting if not set */ REQ_F_REFCOUNT = BIT(REQ_F_REFCOUNT_BIT), /* there is a linked timeout that has to be armed */ REQ_F_ARM_LTIMEOUT = BIT(REQ_F_ARM_LTIMEOUT_BIT), /* ->async_data allocated */ REQ_F_ASYNC_DATA = BIT(REQ_F_ASYNC_DATA_BIT), /* don't post CQEs while failing linked requests */ REQ_F_SKIP_LINK_CQES = BIT(REQ_F_SKIP_LINK_CQES_BIT), /* single poll may be active */ REQ_F_SINGLE_POLL = BIT(REQ_F_SINGLE_POLL_BIT), /* double poll may active */ REQ_F_DOUBLE_POLL = BIT(REQ_F_DOUBLE_POLL_BIT), /* request has already done partial IO */ REQ_F_PARTIAL_IO = BIT(REQ_F_PARTIAL_IO_BIT), }; struct async_poll { struct io_poll_iocb poll; struct io_poll_iocb *double_poll; }; typedef void (*io_req_tw_func_t)(struct io_kiocb *req, bool *locked); struct io_task_work { union { struct io_wq_work_node node; struct llist_node fallback_node; }; io_req_tw_func_t func; }; enum { IORING_RSRC_FILE = 0, IORING_RSRC_BUFFER = 1, }; /* * NOTE! Each of the iocb union members has the file pointer * as the first entry in their struct definition. So you can * access the file pointer through any of the sub-structs, * or directly as just 'file' in this struct. */ struct io_kiocb { union { struct file *file; struct io_rw rw; struct io_poll_iocb poll; struct io_poll_update poll_update; struct io_accept accept; struct io_sync sync; struct io_cancel cancel; struct io_timeout timeout; struct io_timeout_rem timeout_rem; struct io_connect connect; struct io_sr_msg sr_msg; struct io_open open; struct io_close close; struct io_rsrc_update rsrc_update; struct io_fadvise fadvise; struct io_madvise madvise; struct io_epoll epoll; struct io_splice splice; struct io_provide_buf pbuf; struct io_statx statx; struct io_shutdown shutdown; struct io_rename rename; struct io_unlink unlink; struct io_mkdir mkdir; struct io_symlink symlink; struct io_hardlink hardlink; struct io_msg msg; }; u8 opcode; /* polled IO has completed */ u8 iopoll_completed; u16 buf_index; unsigned int flags; u64 user_data; u32 result; u32 cflags; struct io_ring_ctx *ctx; struct task_struct *task; struct percpu_ref *fixed_rsrc_refs; /* store used ubuf, so we can prevent reloading */ struct io_mapped_ubuf *imu; /* used by request caches, completion batching and iopoll */ struct io_wq_work_node comp_list; atomic_t refs; atomic_t poll_refs; struct io_task_work io_task_work; /* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */ struct hlist_node hash_node; /* internal polling, see IORING_FEAT_FAST_POLL */ struct async_poll *apoll; /* opcode allocated if it needs to store data for async defer */ void *async_data; /* stores selected buf, valid IFF REQ_F_BUFFER_SELECTED is set */ struct io_buffer *kbuf; /* linked requests, IFF REQ_F_HARDLINK or REQ_F_LINK are set */ struct io_kiocb *link; /* custom credentials, valid IFF REQ_F_CREDS is set */ const struct cred *creds; struct io_wq_work work; }; struct io_tctx_node { struct list_head ctx_node; struct task_struct *task; struct io_ring_ctx *ctx; }; struct io_defer_entry { struct list_head list; struct io_kiocb *req; u32 seq; }; struct io_op_def { /* needs req->file assigned */ unsigned needs_file : 1; /* should block plug */ unsigned plug : 1; /* hash wq insertion if file is a regular file */ unsigned hash_reg_file : 1; /* unbound wq insertion if file is a non-regular file */ unsigned unbound_nonreg_file : 1; /* set if opcode supports polled "wait" */ unsigned pollin : 1; unsigned pollout : 1; unsigned poll_exclusive : 1; /* op supports buffer selection */ unsigned buffer_select : 1; /* do prep async if is going to be punted */ unsigned needs_async_setup : 1; /* opcode is not supported by this kernel */ unsigned not_supported : 1; /* skip auditing */ unsigned audit_skip : 1; /* size of async data needed, if any */ unsigned short async_size; }; static const struct io_op_def io_op_defs[] = { [IORING_OP_NOP] = {}, [IORING_OP_READV] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .needs_async_setup = 1, .plug = 1, .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_WRITEV] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_async_setup = 1, .plug = 1, .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_FSYNC] = { .needs_file = 1, .audit_skip = 1, }, [IORING_OP_READ_FIXED] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .plug = 1, .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_WRITE_FIXED] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .plug = 1, .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_POLL_ADD] = { .needs_file = 1, .unbound_nonreg_file = 1, .audit_skip = 1, }, [IORING_OP_POLL_REMOVE] = { .audit_skip = 1, }, [IORING_OP_SYNC_FILE_RANGE] = { .needs_file = 1, .audit_skip = 1, }, [IORING_OP_SENDMSG] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_async_setup = 1, .async_size = sizeof(struct io_async_msghdr), }, [IORING_OP_RECVMSG] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .needs_async_setup = 1, .async_size = sizeof(struct io_async_msghdr), }, [IORING_OP_TIMEOUT] = { .audit_skip = 1, .async_size = sizeof(struct io_timeout_data), }, [IORING_OP_TIMEOUT_REMOVE] = { /* used by timeout updates' prep() */ .audit_skip = 1, }, [IORING_OP_ACCEPT] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .poll_exclusive = 1, }, [IORING_OP_ASYNC_CANCEL] = { .audit_skip = 1, }, [IORING_OP_LINK_TIMEOUT] = { .audit_skip = 1, .async_size = sizeof(struct io_timeout_data), }, [IORING_OP_CONNECT] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .needs_async_setup = 1, .async_size = sizeof(struct io_async_connect), }, [IORING_OP_FALLOCATE] = { .needs_file = 1, }, [IORING_OP_OPENAT] = {}, [IORING_OP_CLOSE] = {}, [IORING_OP_FILES_UPDATE] = { .audit_skip = 1, }, [IORING_OP_STATX] = { .audit_skip = 1, }, [IORING_OP_READ] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .plug = 1, .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_WRITE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .plug = 1, .audit_skip = 1, .async_size = sizeof(struct io_async_rw), }, [IORING_OP_FADVISE] = { .needs_file = 1, .audit_skip = 1, }, [IORING_OP_MADVISE] = {}, [IORING_OP_SEND] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollout = 1, .audit_skip = 1, }, [IORING_OP_RECV] = { .needs_file = 1, .unbound_nonreg_file = 1, .pollin = 1, .buffer_select = 1, .audit_skip = 1, }, [IORING_OP_OPENAT2] = { }, [IORING_OP_EPOLL_CTL] = { .unbound_nonreg_file = 1, .audit_skip = 1, }, [IORING_OP_SPLICE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .audit_skip = 1, }, [IORING_OP_PROVIDE_BUFFERS] = { .audit_skip = 1, }, [IORING_OP_REMOVE_BUFFERS] = { .audit_skip = 1, }, [IORING_OP_TEE] = { .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, .audit_skip = 1, }, [IORING_OP_SHUTDOWN] = { .needs_file = 1, }, [IORING_OP_RENAMEAT] = {}, [IORING_OP_UNLINKAT] = {}, [IORING_OP_MKDIRAT] = {}, [IORING_OP_SYMLINKAT] = {}, [IORING_OP_LINKAT] = {}, [IORING_OP_MSG_RING] = { .needs_file = 1, }, }; /* requests with any of those set should undergo io_disarm_next() */ #define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL) static bool io_disarm_next(struct io_kiocb *req); static void io_uring_del_tctx_node(unsigned long index); static void io_uring_try_cancel_requests(struct io_ring_ctx *ctx, struct task_struct *task, bool cancel_all); static void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd); static void io_fill_cqe_req(struct io_kiocb *req, s32 res, u32 cflags); static void io_put_req(struct io_kiocb *req); static void io_put_req_deferred(struct io_kiocb *req); static void io_dismantle_req(struct io_kiocb *req); static void io_queue_linked_timeout(struct io_kiocb *req); static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type, struct io_uring_rsrc_update2 *up, unsigned nr_args); static void io_clean_op(struct io_kiocb *req); static inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd, unsigned issue_flags); static inline struct file *io_file_get_normal(struct io_kiocb *req, int fd); static void io_drop_inflight_file(struct io_kiocb *req); static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags); static void __io_queue_sqe(struct io_kiocb *req); static void io_rsrc_put_work(struct work_struct *work); static void io_req_task_queue(struct io_kiocb *req); static void __io_submit_flush_completions(struct io_ring_ctx *ctx); static int io_req_prep_async(struct io_kiocb *req); static int io_install_fixed_file(struct io_kiocb *req, struct file *file, unsigned int issue_flags, u32 slot_index); static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags); static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer); static void io_eventfd_signal(struct io_ring_ctx *ctx); static struct kmem_cache *req_cachep; static const struct file_operations io_uring_fops; struct sock *io_uring_get_socket(struct file *file) { #if defined(CONFIG_UNIX) if (file->f_op == &io_uring_fops) { struct io_ring_ctx *ctx = file->private_data; return ctx->ring_sock->sk; } #endif return NULL; } EXPORT_SYMBOL(io_uring_get_socket); static inline void io_tw_lock(struct io_ring_ctx *ctx, bool *locked) { if (!*locked) { mutex_lock(&ctx->uring_lock); *locked = true; } } #define io_for_each_link(pos, head) \ for (pos = (head); pos; pos = pos->link) /* * Shamelessly stolen from the mm implementation of page reference checking, * see commit f958d7b528b1 for details. */ #define req_ref_zero_or_close_to_overflow(req) \ ((unsigned int) atomic_read(&(req->refs)) + 127u <= 127u) static inline bool req_ref_inc_not_zero(struct io_kiocb *req) { WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT)); return atomic_inc_not_zero(&req->refs); } static inline bool req_ref_put_and_test(struct io_kiocb *req) { if (likely(!(req->flags & REQ_F_REFCOUNT))) return true; WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req)); return atomic_dec_and_test(&req->refs); } static inline void req_ref_get(struct io_kiocb *req) { WARN_ON_ONCE(!(req->flags & REQ_F_REFCOUNT)); WARN_ON_ONCE(req_ref_zero_or_close_to_overflow(req)); atomic_inc(&req->refs); } static inline void io_submit_flush_completions(struct io_ring_ctx *ctx) { if (!wq_list_empty(&ctx->submit_state.compl_reqs)) __io_submit_flush_completions(ctx); } static inline void __io_req_set_refcount(struct io_kiocb *req, int nr) { if (!(req->flags & REQ_F_REFCOUNT)) { req->flags |= REQ_F_REFCOUNT; atomic_set(&req->refs, nr); } } static inline void io_req_set_refcount(struct io_kiocb *req) { __io_req_set_refcount(req, 1); } #define IO_RSRC_REF_BATCH 100 static inline void io_req_put_rsrc_locked(struct io_kiocb *req, struct io_ring_ctx *ctx) __must_hold(&ctx->uring_lock) { struct percpu_ref *ref = req->fixed_rsrc_refs; if (ref) { if (ref == &ctx->rsrc_node->refs) ctx->rsrc_cached_refs++; else percpu_ref_put(ref); } } static inline void io_req_put_rsrc(struct io_kiocb *req, struct io_ring_ctx *ctx) { if (req->fixed_rsrc_refs) percpu_ref_put(req->fixed_rsrc_refs); } static __cold void io_rsrc_refs_drop(struct io_ring_ctx *ctx) __must_hold(&ctx->uring_lock) { if (ctx->rsrc_cached_refs) { percpu_ref_put_many(&ctx->rsrc_node->refs, ctx->rsrc_cached_refs); ctx->rsrc_cached_refs = 0; } } static void io_rsrc_refs_refill(struct io_ring_ctx *ctx) __must_hold(&ctx->uring_lock) { ctx->rsrc_cached_refs += IO_RSRC_REF_BATCH; percpu_ref_get_many(&ctx->rsrc_node->refs, IO_RSRC_REF_BATCH); } static inline void io_req_set_rsrc_node(struct io_kiocb *req, struct io_ring_ctx *ctx, unsigned int issue_flags) { if (!req->fixed_rsrc_refs) { req->fixed_rsrc_refs = &ctx->rsrc_node->refs; if (!(issue_flags & IO_URING_F_UNLOCKED)) { lockdep_assert_held(&ctx->uring_lock); ctx->rsrc_cached_refs--; if (unlikely(ctx->rsrc_cached_refs < 0)) io_rsrc_refs_refill(ctx); } else { percpu_ref_get(req->fixed_rsrc_refs); } } } static unsigned int __io_put_kbuf(struct io_kiocb *req, struct list_head *list) { struct io_buffer *kbuf = req->kbuf; unsigned int cflags; cflags = IORING_CQE_F_BUFFER | (kbuf->bid << IORING_CQE_BUFFER_SHIFT); req->flags &= ~REQ_F_BUFFER_SELECTED; list_add(&kbuf->list, list); req->kbuf = NULL; return cflags; } static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req) { lockdep_assert_held(&req->ctx->completion_lock); if (likely(!(req->flags & REQ_F_BUFFER_SELECTED))) return 0; return __io_put_kbuf(req, &req->ctx->io_buffers_comp); } static inline unsigned int io_put_kbuf(struct io_kiocb *req, unsigned issue_flags) { unsigned int cflags; if (likely(!(req->flags & REQ_F_BUFFER_SELECTED))) return 0; /* * We can add this buffer back to two lists: * * 1) The io_buffers_cache list. This one is protected by the * ctx->uring_lock. If we already hold this lock, add back to this * list as we can grab it from issue as well. * 2) The io_buffers_comp list. This one is protected by the * ctx->completion_lock. * * We migrate buffers from the comp_list to the issue cache list * when we need one. */ if (issue_flags & IO_URING_F_UNLOCKED) { struct io_ring_ctx *ctx = req->ctx; spin_lock(&ctx->completion_lock); cflags = __io_put_kbuf(req, &ctx->io_buffers_comp); spin_unlock(&ctx->completion_lock); } else { lockdep_assert_held(&req->ctx->uring_lock); cflags = __io_put_kbuf(req, &req->ctx->io_buffers_cache); } return cflags; } static struct io_buffer_list *io_buffer_get_list(struct io_ring_ctx *ctx, unsigned int bgid) { struct list_head *hash_list; struct io_buffer_list *bl; hash_list = &ctx->io_buffers[hash_32(bgid, IO_BUFFERS_HASH_BITS)]; list_for_each_entry(bl, hash_list, list) if (bl->bgid == bgid || bgid == -1U) return bl; return NULL; } static void io_kbuf_recycle(struct io_kiocb *req, unsigned issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; struct io_buffer *buf; if (likely(!(req->flags & REQ_F_BUFFER_SELECTED))) return; /* don't recycle if we already did IO to this buffer */ if (req->flags & REQ_F_PARTIAL_IO) return; if (issue_flags & IO_URING_F_UNLOCKED) mutex_lock(&ctx->uring_lock); lockdep_assert_held(&ctx->uring_lock); buf = req->kbuf; bl = io_buffer_get_list(ctx, buf->bgid); list_add(&buf->list, &bl->buf_list); req->flags &= ~REQ_F_BUFFER_SELECTED; req->kbuf = NULL; if (issue_flags & IO_URING_F_UNLOCKED) mutex_unlock(&ctx->uring_lock); } static bool io_match_task(struct io_kiocb *head, struct task_struct *task, bool cancel_all) __must_hold(&req->ctx->timeout_lock) { if (task && head->task != task) return false; return cancel_all; } /* * As io_match_task() but protected against racing with linked timeouts. * User must not hold timeout_lock. */ static bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task, bool cancel_all) { if (task && head->task != task) return false; return cancel_all; } static inline bool req_has_async_data(struct io_kiocb *req) { return req->flags & REQ_F_ASYNC_DATA; } static inline void req_set_fail(struct io_kiocb *req) { req->flags |= REQ_F_FAIL; if (req->flags & REQ_F_CQE_SKIP) { req->flags &= ~REQ_F_CQE_SKIP; req->flags |= REQ_F_SKIP_LINK_CQES; } } static inline void req_fail_link_node(struct io_kiocb *req, int res) { req_set_fail(req); req->result = res; } static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref) { struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); complete(&ctx->ref_comp); } static inline bool io_is_timeout_noseq(struct io_kiocb *req) { return !req->timeout.off; } static __cold void io_fallback_req_func(struct work_struct *work) { struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, fallback_work.work); struct llist_node *node = llist_del_all(&ctx->fallback_llist); struct io_kiocb *req, *tmp; bool locked = false; percpu_ref_get(&ctx->refs); llist_for_each_entry_safe(req, tmp, node, io_task_work.fallback_node) req->io_task_work.func(req, &locked); if (locked) { io_submit_flush_completions(ctx); mutex_unlock(&ctx->uring_lock); } percpu_ref_put(&ctx->refs); } static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) { struct io_ring_ctx *ctx; int i, hash_bits; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return NULL; /* * Use 5 bits less than the max cq entries, that should give us around * 32 entries per hash list if totally full and uniformly spread. */ hash_bits = ilog2(p->cq_entries); hash_bits -= 5; if (hash_bits <= 0) hash_bits = 1; ctx->cancel_hash_bits = hash_bits; ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head), GFP_KERNEL); if (!ctx->cancel_hash) goto err; __hash_init(ctx->cancel_hash, 1U << hash_bits); ctx->dummy_ubuf = kzalloc(sizeof(*ctx->dummy_ubuf), GFP_KERNEL); if (!ctx->dummy_ubuf) goto err; /* set invalid range, so io_import_fixed() fails meeting it */ ctx->dummy_ubuf->ubuf = -1UL; ctx->io_buffers = kcalloc(1U << IO_BUFFERS_HASH_BITS, sizeof(struct list_head), GFP_KERNEL); if (!ctx->io_buffers) goto err; for (i = 0; i < (1U << IO_BUFFERS_HASH_BITS); i++) INIT_LIST_HEAD(&ctx->io_buffers[i]); if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) goto err; ctx->flags = p->flags; init_waitqueue_head(&ctx->sqo_sq_wait); INIT_LIST_HEAD(&ctx->sqd_list); INIT_LIST_HEAD(&ctx->cq_overflow_list); INIT_LIST_HEAD(&ctx->io_buffers_cache); INIT_LIST_HEAD(&ctx->apoll_cache); init_completion(&ctx->ref_comp); xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1); mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->cq_wait); spin_lock_init(&ctx->completion_lock); spin_lock_init(&ctx->timeout_lock); INIT_WQ_LIST(&ctx->iopoll_list); INIT_LIST_HEAD(&ctx->io_buffers_pages); INIT_LIST_HEAD(&ctx->io_buffers_comp); INIT_LIST_HEAD(&ctx->defer_list); INIT_LIST_HEAD(&ctx->timeout_list); INIT_LIST_HEAD(&ctx->ltimeout_list); spin_lock_init(&ctx->rsrc_ref_lock); INIT_LIST_HEAD(&ctx->rsrc_ref_list); INIT_DELAYED_WORK(&ctx->rsrc_put_work, io_rsrc_put_work); init_llist_head(&ctx->rsrc_put_llist); INIT_LIST_HEAD(&ctx->tctx_list); ctx->submit_state.free_list.next = NULL; INIT_WQ_LIST(&ctx->locked_free_list); INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func); INIT_WQ_LIST(&ctx->submit_state.compl_reqs); return ctx; err: kfree(ctx->dummy_ubuf); kfree(ctx->cancel_hash); kfree(ctx->io_buffers); kfree(ctx); return NULL; } static void io_account_cq_overflow(struct io_ring_ctx *ctx) { struct io_rings *r = ctx->rings; WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1); ctx->cq_extra--; } static bool req_need_defer(struct io_kiocb *req, u32 seq) { if (unlikely(req->flags & REQ_F_IO_DRAIN)) { struct io_ring_ctx *ctx = req->ctx; return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail; } return false; } #define FFS_NOWAIT 0x1UL #define FFS_ISREG 0x2UL #define FFS_MASK ~(FFS_NOWAIT|FFS_ISREG) static inline bool io_req_ffs_set(struct io_kiocb *req) { return req->flags & REQ_F_FIXED_FILE; } static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req) { if (WARN_ON_ONCE(!req->link)) return NULL; req->flags &= ~REQ_F_ARM_LTIMEOUT; req->flags |= REQ_F_LINK_TIMEOUT; /* linked timeouts should have two refs once prep'ed */ io_req_set_refcount(req); __io_req_set_refcount(req->link, 2); return req->link; } static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req) { if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT))) return NULL; return __io_prep_linked_timeout(req); } static void io_prep_async_work(struct io_kiocb *req) { const struct io_op_def *def = &io_op_defs[req->opcode]; struct io_ring_ctx *ctx = req->ctx; if (!(req->flags & REQ_F_CREDS)) { req->flags |= REQ_F_CREDS; req->creds = get_current_cred(); } req->work.list.next = NULL; req->work.flags = 0; if (req->flags & REQ_F_FORCE_ASYNC) req->work.flags |= IO_WQ_WORK_CONCURRENT; if (req->flags & REQ_F_ISREG) { if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL)) io_wq_hash_work(&req->work, file_inode(req->file)); } else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) { if (def->unbound_nonreg_file) req->work.flags |= IO_WQ_WORK_UNBOUND; } } static void io_prep_async_link(struct io_kiocb *req) { struct io_kiocb *cur; if (req->flags & REQ_F_LINK_TIMEOUT) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->timeout_lock); io_for_each_link(cur, req) io_prep_async_work(cur); spin_unlock_irq(&ctx->timeout_lock); } else { io_for_each_link(cur, req) io_prep_async_work(cur); } } static inline void io_req_add_compl_list(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_submit_state *state = &ctx->submit_state; if (!(req->flags & REQ_F_CQE_SKIP)) ctx->submit_state.flush_cqes = true; wq_list_add_tail(&req->comp_list, &state->compl_reqs); } static void io_queue_async_work(struct io_kiocb *req, bool *dont_use) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *link = io_prep_linked_timeout(req); struct io_uring_task *tctx = req->task->io_uring; BUG_ON(!tctx); BUG_ON(!tctx->io_wq); /* init ->work of the whole link before punting */ io_prep_async_link(req); /* * Not expected to happen, but if we do have a bug where this _can_ * happen, catch it here and ensure the request is marked as * canceled. That will make io-wq go through the usual work cancel * procedure rather than attempt to run this request (or create a new * worker for it). */ if (WARN_ON_ONCE(!same_thread_group(req->task, current))) req->work.flags |= IO_WQ_WORK_CANCEL; trace_io_uring_queue_async_work(ctx, req, req->user_data, req->opcode, req->flags, &req->work, io_wq_is_hashed(&req->work)); io_wq_enqueue(tctx->io_wq, &req->work); if (link) io_queue_linked_timeout(link); } static void io_kill_timeout(struct io_kiocb *req, int status) __must_hold(&req->ctx->completion_lock) __must_hold(&req->ctx->timeout_lock) { struct io_timeout_data *io = req->async_data; if (hrtimer_try_to_cancel(&io->timer) != -1) { if (status) req_set_fail(req); atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); list_del_init(&req->timeout.list); io_fill_cqe_req(req, status, 0); io_put_req_deferred(req); } } static __cold void io_queue_deferred(struct io_ring_ctx *ctx) { while (!list_empty(&ctx->defer_list)) { struct io_defer_entry *de = list_first_entry(&ctx->defer_list, struct io_defer_entry, list); if (req_need_defer(de->req, de->seq)) break; list_del_init(&de->list); io_req_task_queue(de->req); kfree(de); } } static __cold void io_flush_timeouts(struct io_ring_ctx *ctx) __must_hold(&ctx->completion_lock) { u32 seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); struct io_kiocb *req, *tmp; spin_lock_irq(&ctx->timeout_lock); list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) { u32 events_needed, events_got; if (io_is_timeout_noseq(req)) break; /* * Since seq can easily wrap around over time, subtract * the last seq at which timeouts were flushed before comparing. * Assuming not more than 2^31-1 events have happened since, * these subtractions won't have wrapped, so we can check if * target is in [last_seq, current_seq] by comparing the two. */ events_needed = req->timeout.target_seq - ctx->cq_last_tm_flush; events_got = seq - ctx->cq_last_tm_flush; if (events_got < events_needed) break; io_kill_timeout(req, 0); } ctx->cq_last_tm_flush = seq; spin_unlock_irq(&ctx->timeout_lock); } static inline void io_commit_cqring(struct io_ring_ctx *ctx) { /* order cqe stores with ring update */ smp_store_release(&ctx->rings->cq.tail, ctx->cached_cq_tail); } static void __io_commit_cqring_flush(struct io_ring_ctx *ctx) { if (ctx->off_timeout_used || ctx->drain_active) { spin_lock(&ctx->completion_lock); if (ctx->off_timeout_used) io_flush_timeouts(ctx); if (ctx->drain_active) io_queue_deferred(ctx); io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); } if (ctx->has_evfd) io_eventfd_signal(ctx); } static inline bool io_sqring_full(struct io_ring_ctx *ctx) { struct io_rings *r = ctx->rings; return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == ctx->sq_entries; } static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx) { return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head); } static inline struct io_uring_cqe *io_get_cqe(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; unsigned tail, mask = ctx->cq_entries - 1; /* * writes to the cq entry need to come after reading head; the * control dependency is enough as we're using WRITE_ONCE to * fill the cq entry */ if (__io_cqring_events(ctx) == ctx->cq_entries) return NULL; tail = ctx->cached_cq_tail++; return &rings->cqes[tail & mask]; } static void io_eventfd_signal(struct io_ring_ctx *ctx) { struct io_ev_fd *ev_fd; rcu_read_lock(); /* * rcu_dereference ctx->io_ev_fd once and use it for both for checking * and eventfd_signal */ ev_fd = rcu_dereference(ctx->io_ev_fd); /* * Check again if ev_fd exists incase an io_eventfd_unregister call * completed between the NULL check of ctx->io_ev_fd at the start of * the function and rcu_read_lock. */ if (unlikely(!ev_fd)) goto out; if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED) goto out; if (!ev_fd->eventfd_async || io_wq_current_is_worker()) eventfd_signal(ev_fd->cq_ev_fd, 1); out: rcu_read_unlock(); } static inline void io_cqring_wake(struct io_ring_ctx *ctx) { /* * wake_up_all() may seem excessive, but io_wake_function() and * io_should_wake() handle the termination of the loop and only * wake as many waiters as we need to. */ if (wq_has_sleeper(&ctx->cq_wait)) wake_up_all(&ctx->cq_wait); } /* * This should only get called when at least one event has been posted. * Some applications rely on the eventfd notification count only changing * IFF a new CQE has been added to the CQ ring. There's no depedency on * 1:1 relationship between how many times this function is called (and * hence the eventfd count) and number of CQEs posted to the CQ ring. */ static inline void io_cqring_ev_posted(struct io_ring_ctx *ctx) { if (unlikely(ctx->off_timeout_used || ctx->drain_active || ctx->has_evfd)) __io_commit_cqring_flush(ctx); io_cqring_wake(ctx); } static void io_cqring_ev_posted_iopoll(struct io_ring_ctx *ctx) { if (unlikely(ctx->off_timeout_used || ctx->drain_active || ctx->has_evfd)) __io_commit_cqring_flush(ctx); if (ctx->flags & IORING_SETUP_SQPOLL) io_cqring_wake(ctx); } /* Returns true if there are no backlogged entries after the flush */ static bool __io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force) { bool all_flushed, posted; if (!force && __io_cqring_events(ctx) == ctx->cq_entries) return false; posted = false; spin_lock(&ctx->completion_lock); while (!list_empty(&ctx->cq_overflow_list)) { struct io_uring_cqe *cqe = io_get_cqe(ctx); struct io_overflow_cqe *ocqe; if (!cqe && !force) break; ocqe = list_first_entry(&ctx->cq_overflow_list, struct io_overflow_cqe, list); if (cqe) memcpy(cqe, &ocqe->cqe, sizeof(*cqe)); else io_account_cq_overflow(ctx); posted = true; list_del(&ocqe->list); kfree(ocqe); } all_flushed = list_empty(&ctx->cq_overflow_list); if (all_flushed) { clear_bit(0, &ctx->check_cq_overflow); WRITE_ONCE(ctx->rings->sq_flags, ctx->rings->sq_flags & ~IORING_SQ_CQ_OVERFLOW); } if (posted) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); if (posted) io_cqring_ev_posted(ctx); return all_flushed; } static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx) { bool ret = true; if (test_bit(0, &ctx->check_cq_overflow)) { /* iopoll syncs against uring_lock, not completion_lock */ if (ctx->flags & IORING_SETUP_IOPOLL) mutex_lock(&ctx->uring_lock); ret = __io_cqring_overflow_flush(ctx, false); if (ctx->flags & IORING_SETUP_IOPOLL) mutex_unlock(&ctx->uring_lock); } return ret; } /* must to be called somewhat shortly after putting a request */ static inline void io_put_task(struct task_struct *task, int nr) { struct io_uring_task *tctx = task->io_uring; if (likely(task == current)) { tctx->cached_refs += nr; } else { percpu_counter_sub(&tctx->inflight, nr); if (unlikely(atomic_read(&tctx->in_idle))) wake_up(&tctx->wait); put_task_struct_many(task, nr); } } static void io_task_refs_refill(struct io_uring_task *tctx) { unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR; percpu_counter_add(&tctx->inflight, refill); refcount_add(refill, ¤t->usage); tctx->cached_refs += refill; } static inline void io_get_task_refs(int nr) { struct io_uring_task *tctx = current->io_uring; tctx->cached_refs -= nr; if (unlikely(tctx->cached_refs < 0)) io_task_refs_refill(tctx); } static __cold void io_uring_drop_tctx_refs(struct task_struct *task) { struct io_uring_task *tctx = task->io_uring; unsigned int refs = tctx->cached_refs; if (refs) { tctx->cached_refs = 0; percpu_counter_sub(&tctx->inflight, refs); put_task_struct_many(task, refs); } } static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags) { struct io_overflow_cqe *ocqe; ocqe = kmalloc(sizeof(*ocqe), GFP_ATOMIC | __GFP_ACCOUNT); if (!ocqe) { /* * If we're in ring overflow flush mode, or in task cancel mode, * or cannot allocate an overflow entry, then we need to drop it * on the floor. */ io_account_cq_overflow(ctx); return false; } if (list_empty(&ctx->cq_overflow_list)) { set_bit(0, &ctx->check_cq_overflow); WRITE_ONCE(ctx->rings->sq_flags, ctx->rings->sq_flags | IORING_SQ_CQ_OVERFLOW); } ocqe->cqe.user_data = user_data; ocqe->cqe.res = res; ocqe->cqe.flags = cflags; list_add_tail(&ocqe->list, &ctx->cq_overflow_list); return true; } static inline bool __io_fill_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags) { struct io_uring_cqe *cqe; /* * If we can't get a cq entry, userspace overflowed the * submission (by quite a lot). Increment the overflow count in * the ring. */ cqe = io_get_cqe(ctx); if (likely(cqe)) { WRITE_ONCE(cqe->user_data, user_data); WRITE_ONCE(cqe->res, res); WRITE_ONCE(cqe->flags, cflags); return true; } return io_cqring_event_overflow(ctx, user_data, res, cflags); } static inline bool __io_fill_cqe_req(struct io_kiocb *req, s32 res, u32 cflags) { trace_io_uring_complete(req->ctx, req, req->user_data, res, cflags); return __io_fill_cqe(req->ctx, req->user_data, res, cflags); } static noinline void io_fill_cqe_req(struct io_kiocb *req, s32 res, u32 cflags) { if (!(req->flags & REQ_F_CQE_SKIP)) __io_fill_cqe_req(req, res, cflags); } static noinline bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags) { ctx->cq_extra++; trace_io_uring_complete(ctx, NULL, user_data, res, cflags); return __io_fill_cqe(ctx, user_data, res, cflags); } static void __io_req_complete_post(struct io_kiocb *req, s32 res, u32 cflags) { struct io_ring_ctx *ctx = req->ctx; if (!(req->flags & REQ_F_CQE_SKIP)) __io_fill_cqe_req(req, res, cflags); /* * If we're the last reference to this request, add to our locked * free_list cache. */ if (req_ref_put_and_test(req)) { if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) { if (req->flags & IO_DISARM_MASK) io_disarm_next(req); if (req->link) { io_req_task_queue(req->link); req->link = NULL; } } io_req_put_rsrc(req, ctx); /* * Selected buffer deallocation in io_clean_op() assumes that * we don't hold ->completion_lock. Clean them here to avoid * deadlocks. */ io_put_kbuf_comp(req); io_dismantle_req(req); io_put_task(req->task, 1); wq_list_add_head(&req->comp_list, &ctx->locked_free_list); ctx->locked_free_nr++; } } static void io_req_complete_post(struct io_kiocb *req, s32 res, u32 cflags) { struct io_ring_ctx *ctx = req->ctx; spin_lock(&ctx->completion_lock); __io_req_complete_post(req, res, cflags); io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_cqring_ev_posted(ctx); } static inline void io_req_complete_state(struct io_kiocb *req, s32 res, u32 cflags) { req->result = res; req->cflags = cflags; req->flags |= REQ_F_COMPLETE_INLINE; } static inline void __io_req_complete(struct io_kiocb *req, unsigned issue_flags, s32 res, u32 cflags) { if (issue_flags & IO_URING_F_COMPLETE_DEFER) io_req_complete_state(req, res, cflags); else io_req_complete_post(req, res, cflags); } static inline void io_req_complete(struct io_kiocb *req, s32 res) { __io_req_complete(req, 0, res, 0); } static void io_req_complete_failed(struct io_kiocb *req, s32 res) { req_set_fail(req); io_req_complete_post(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED)); } static void io_req_complete_fail_submit(struct io_kiocb *req) { /* * We don't submit, fail them all, for that replace hardlinks with * normal links. Extra REQ_F_LINK is tolerated. */ req->flags &= ~REQ_F_HARDLINK; req->flags |= REQ_F_LINK; io_req_complete_failed(req, req->result); } /* * Don't initialise the fields below on every allocation, but do that in * advance and keep them valid across allocations. */ static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx) { req->ctx = ctx; req->link = NULL; req->async_data = NULL; /* not necessary, but safer to zero */ req->result = 0; } static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx, struct io_submit_state *state) { spin_lock(&ctx->completion_lock); wq_list_splice(&ctx->locked_free_list, &state->free_list); ctx->locked_free_nr = 0; spin_unlock(&ctx->completion_lock); } /* Returns true IFF there are requests in the cache */ static bool io_flush_cached_reqs(struct io_ring_ctx *ctx) { struct io_submit_state *state = &ctx->submit_state; /* * If we have more than a batch's worth of requests in our IRQ side * locked cache, grab the lock and move them over to our submission * side cache. */ if (READ_ONCE(ctx->locked_free_nr) > IO_COMPL_BATCH) io_flush_cached_locked_reqs(ctx, state); return !!state->free_list.next; } /* * A request might get retired back into the request caches even before opcode * handlers and io_issue_sqe() are done with it, e.g. inline completion path. * Because of that, io_alloc_req() should be called only under ->uring_lock * and with extra caution to not get a request that is still worked on. */ static __cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx) __must_hold(&ctx->uring_lock) { struct io_submit_state *state = &ctx->submit_state; gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; void *reqs[IO_REQ_ALLOC_BATCH]; struct io_kiocb *req; int ret, i; if (likely(state->free_list.next || io_flush_cached_reqs(ctx))) return true; ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs); /* * Bulk alloc is all-or-nothing. If we fail to get a batch, * retry single alloc to be on the safe side. */ if (unlikely(ret <= 0)) { reqs[0] = kmem_cache_alloc(req_cachep, gfp); if (!reqs[0]) return false; ret = 1; } percpu_ref_get_many(&ctx->refs, ret); for (i = 0; i < ret; i++) { req = reqs[i]; io_preinit_req(req, ctx); wq_stack_add_head(&req->comp_list, &state->free_list); } return true; } static inline bool io_alloc_req_refill(struct io_ring_ctx *ctx) { if (unlikely(!ctx->submit_state.free_list.next)) return __io_alloc_req_refill(ctx); return true; } static inline struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx) { struct io_wq_work_node *node; node = wq_stack_extract(&ctx->submit_state.free_list); return container_of(node, struct io_kiocb, comp_list); } static inline void io_put_file(struct file *file) { if (file) fput(file); } static inline void io_dismantle_req(struct io_kiocb *req) { unsigned int flags = req->flags; if (unlikely(flags & IO_REQ_CLEAN_FLAGS)) io_clean_op(req); if (!(flags & REQ_F_FIXED_FILE)) io_put_file(req->file); } static __cold void __io_free_req(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; io_req_put_rsrc(req, ctx); io_dismantle_req(req); io_put_task(req->task, 1); spin_lock(&ctx->completion_lock); wq_list_add_head(&req->comp_list, &ctx->locked_free_list); ctx->locked_free_nr++; spin_unlock(&ctx->completion_lock); } static inline void io_remove_next_linked(struct io_kiocb *req) { struct io_kiocb *nxt = req->link; req->link = nxt->link; nxt->link = NULL; } static bool io_kill_linked_timeout(struct io_kiocb *req) __must_hold(&req->ctx->completion_lock) __must_hold(&req->ctx->timeout_lock) { struct io_kiocb *link = req->link; if (link && link->opcode == IORING_OP_LINK_TIMEOUT) { struct io_timeout_data *io = link->async_data; io_remove_next_linked(req); link->timeout.head = NULL; if (hrtimer_try_to_cancel(&io->timer) != -1) { list_del(&link->timeout.list); /* leave REQ_F_CQE_SKIP to io_fill_cqe_req */ io_fill_cqe_req(link, -ECANCELED, 0); io_put_req_deferred(link); return true; } } return false; } static void io_fail_links(struct io_kiocb *req) __must_hold(&req->ctx->completion_lock) { struct io_kiocb *nxt, *link = req->link; bool ignore_cqes = req->flags & REQ_F_SKIP_LINK_CQES; req->link = NULL; while (link) { long res = -ECANCELED; if (link->flags & REQ_F_FAIL) res = link->result; nxt = link->link; link->link = NULL; trace_io_uring_fail_link(req->ctx, req, req->user_data, req->opcode, link); if (!ignore_cqes) { link->flags &= ~REQ_F_CQE_SKIP; io_fill_cqe_req(link, res, 0); } io_put_req_deferred(link); link = nxt; } } static bool io_disarm_next(struct io_kiocb *req) __must_hold(&req->ctx->completion_lock) { bool posted = false; if (req->flags & REQ_F_ARM_LTIMEOUT) { struct io_kiocb *link = req->link; req->flags &= ~REQ_F_ARM_LTIMEOUT; if (link && link->opcode == IORING_OP_LINK_TIMEOUT) { io_remove_next_linked(req); /* leave REQ_F_CQE_SKIP to io_fill_cqe_req */ io_fill_cqe_req(link, -ECANCELED, 0); io_put_req_deferred(link); posted = true; } } else if (req->flags & REQ_F_LINK_TIMEOUT) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->timeout_lock); posted = io_kill_linked_timeout(req); spin_unlock_irq(&ctx->timeout_lock); } if (unlikely((req->flags & REQ_F_FAIL) && !(req->flags & REQ_F_HARDLINK))) { posted |= (req->link != NULL); io_fail_links(req); } return posted; } static void __io_req_find_next_prep(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; bool posted; spin_lock(&ctx->completion_lock); posted = io_disarm_next(req); if (posted) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); if (posted) io_cqring_ev_posted(ctx); } static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req) { struct io_kiocb *nxt; if (likely(!(req->flags & (REQ_F_LINK|REQ_F_HARDLINK)))) return NULL; /* * If LINK is set, we have dependent requests in this chain. If we * didn't fail this request, queue the first one up, moving any other * dependencies to the next request. In case of failure, fail the rest * of the chain. */ if (unlikely(req->flags & IO_DISARM_MASK)) __io_req_find_next_prep(req); nxt = req->link; req->link = NULL; return nxt; } static void ctx_flush_and_put(struct io_ring_ctx *ctx, bool *locked) { if (!ctx) return; if (*locked) { io_submit_flush_completions(ctx); mutex_unlock(&ctx->uring_lock); *locked = false; } percpu_ref_put(&ctx->refs); } static inline void ctx_commit_and_unlock(struct io_ring_ctx *ctx) { io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_cqring_ev_posted(ctx); } static void handle_prev_tw_list(struct io_wq_work_node *node, struct io_ring_ctx **ctx, bool *uring_locked) { if (*ctx && !*uring_locked) spin_lock(&(*ctx)->completion_lock); do { struct io_wq_work_node *next = node->next; struct io_kiocb *req = container_of(node, struct io_kiocb, io_task_work.node); prefetch(container_of(next, struct io_kiocb, io_task_work.node)); if (req->ctx != *ctx) { if (unlikely(!*uring_locked && *ctx)) ctx_commit_and_unlock(*ctx); ctx_flush_and_put(*ctx, uring_locked); *ctx = req->ctx; /* if not contended, grab and improve batching */ *uring_locked = mutex_trylock(&(*ctx)->uring_lock); percpu_ref_get(&(*ctx)->refs); if (unlikely(!*uring_locked)) spin_lock(&(*ctx)->completion_lock); } if (likely(*uring_locked)) req->io_task_work.func(req, uring_locked); else __io_req_complete_post(req, req->result, io_put_kbuf_comp(req)); node = next; } while (node); if (unlikely(!*uring_locked)) ctx_commit_and_unlock(*ctx); } static void handle_tw_list(struct io_wq_work_node *node, struct io_ring_ctx **ctx, bool *locked) { do { struct io_wq_work_node *next = node->next; struct io_kiocb *req = container_of(node, struct io_kiocb, io_task_work.node); prefetch(container_of(next, struct io_kiocb, io_task_work.node)); if (req->ctx != *ctx) { ctx_flush_and_put(*ctx, locked); *ctx = req->ctx; /* if not contended, grab and improve batching */ *locked = mutex_trylock(&(*ctx)->uring_lock); percpu_ref_get(&(*ctx)->refs); } req->io_task_work.func(req, locked); node = next; } while (node); } static void tctx_task_work(struct callback_head *cb) { bool uring_locked = false; struct io_ring_ctx *ctx = NULL; struct io_uring_task *tctx = container_of(cb, struct io_uring_task, task_work); while (1) { struct io_wq_work_node *node1, *node2; if (!tctx->task_list.first && !tctx->prior_task_list.first && uring_locked) io_submit_flush_completions(ctx); spin_lock_irq(&tctx->task_lock); node1 = tctx->prior_task_list.first; node2 = tctx->task_list.first; INIT_WQ_LIST(&tctx->task_list); INIT_WQ_LIST(&tctx->prior_task_list); if (!node2 && !node1) tctx->task_running = false; spin_unlock_irq(&tctx->task_lock); if (!node2 && !node1) break; if (node1) handle_prev_tw_list(node1, &ctx, &uring_locked); if (node2) handle_tw_list(node2, &ctx, &uring_locked); cond_resched(); } ctx_flush_and_put(ctx, &uring_locked); /* relaxed read is enough as only the task itself sets ->in_idle */ if (unlikely(atomic_read(&tctx->in_idle))) io_uring_drop_tctx_refs(current); } static void io_req_task_work_add(struct io_kiocb *req, bool priority) { struct task_struct *tsk = req->task; struct io_uring_task *tctx = tsk->io_uring; enum task_work_notify_mode notify; struct io_wq_work_node *node; unsigned long flags; bool running; WARN_ON_ONCE(!tctx); io_drop_inflight_file(req); spin_lock_irqsave(&tctx->task_lock, flags); if (priority) wq_list_add_tail(&req->io_task_work.node, &tctx->prior_task_list); else wq_list_add_tail(&req->io_task_work.node, &tctx->task_list); running = tctx->task_running; if (!running) tctx->task_running = true; spin_unlock_irqrestore(&tctx->task_lock, flags); /* task_work already pending, we're done */ if (running) return; /* * SQPOLL kernel thread doesn't need notification, just a wakeup. For * all other cases, use TWA_SIGNAL unconditionally to ensure we're * processing task_work. There's no reliable way to tell if TWA_RESUME * will do the job. */ notify = (req->ctx->flags & IORING_SETUP_SQPOLL) ? TWA_NONE : TWA_SIGNAL; if (likely(!task_work_add(tsk, &tctx->task_work, notify))) { if (notify == TWA_NONE) wake_up_process(tsk); return; } spin_lock_irqsave(&tctx->task_lock, flags); tctx->task_running = false; node = wq_list_merge(&tctx->prior_task_list, &tctx->task_list); spin_unlock_irqrestore(&tctx->task_lock, flags); while (node) { req = container_of(node, struct io_kiocb, io_task_work.node); node = node->next; if (llist_add(&req->io_task_work.fallback_node, &req->ctx->fallback_llist)) schedule_delayed_work(&req->ctx->fallback_work, 1); } } static void io_req_task_cancel(struct io_kiocb *req, bool *locked) { struct io_ring_ctx *ctx = req->ctx; /* not needed for normal modes, but SQPOLL depends on it */ io_tw_lock(ctx, locked); io_req_complete_failed(req, req->result); } static void io_req_task_submit(struct io_kiocb *req, bool *locked) { struct io_ring_ctx *ctx = req->ctx; io_tw_lock(ctx, locked); /* req->task == current here, checking PF_EXITING is safe */ if (likely(!(req->task->flags & PF_EXITING))) __io_queue_sqe(req); else io_req_complete_failed(req, -EFAULT); } static void io_req_task_queue_fail(struct io_kiocb *req, int ret) { req->result = ret; req->io_task_work.func = io_req_task_cancel; io_req_task_work_add(req, false); } static void io_req_task_queue(struct io_kiocb *req) { req->io_task_work.func = io_req_task_submit; io_req_task_work_add(req, false); } static void io_req_task_queue_reissue(struct io_kiocb *req) { req->io_task_work.func = io_queue_async_work; io_req_task_work_add(req, false); } static inline void io_queue_next(struct io_kiocb *req) { struct io_kiocb *nxt = io_req_find_next(req); if (nxt) io_req_task_queue(nxt); } static void io_free_req(struct io_kiocb *req) { io_queue_next(req); __io_free_req(req); } static void io_free_req_work(struct io_kiocb *req, bool *locked) { io_free_req(req); } static void io_free_batch_list(struct io_ring_ctx *ctx, struct io_wq_work_node *node) __must_hold(&ctx->uring_lock) { struct task_struct *task = NULL; int task_refs = 0; do { struct io_kiocb *req = container_of(node, struct io_kiocb, comp_list); if (unlikely(req->flags & REQ_F_REFCOUNT)) { node = req->comp_list.next; if (!req_ref_put_and_test(req)) continue; } io_req_put_rsrc_locked(req, ctx); io_queue_next(req); io_dismantle_req(req); if (req->task != task) { if (task) io_put_task(task, task_refs); task = req->task; task_refs = 0; } task_refs++; node = req->comp_list.next; wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list); } while (node); if (task) io_put_task(task, task_refs); } static void __io_submit_flush_completions(struct io_ring_ctx *ctx) __must_hold(&ctx->uring_lock) { struct io_wq_work_node *node, *prev; struct io_submit_state *state = &ctx->submit_state; if (state->flush_cqes) { spin_lock(&ctx->completion_lock); wq_list_for_each(node, prev, &state->compl_reqs) { struct io_kiocb *req = container_of(node, struct io_kiocb, comp_list); if (!(req->flags & REQ_F_CQE_SKIP)) __io_fill_cqe_req(req, req->result, req->cflags); if ((req->flags & REQ_F_POLLED) && req->apoll) { struct async_poll *apoll = req->apoll; if (apoll->double_poll) kfree(apoll->double_poll); list_add(&apoll->poll.wait.entry, &ctx->apoll_cache); req->flags &= ~REQ_F_POLLED; } } io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_cqring_ev_posted(ctx); state->flush_cqes = false; } io_free_batch_list(ctx, state->compl_reqs.first); INIT_WQ_LIST(&state->compl_reqs); } /* * Drop reference to request, return next in chain (if there is one) if this * was the last reference to this request. */ static inline struct io_kiocb *io_put_req_find_next(struct io_kiocb *req) { struct io_kiocb *nxt = NULL; if (req_ref_put_and_test(req)) { nxt = io_req_find_next(req); __io_free_req(req); } return nxt; } static inline void io_put_req(struct io_kiocb *req) { if (req_ref_put_and_test(req)) io_free_req(req); } static inline void io_put_req_deferred(struct io_kiocb *req) { if (req_ref_put_and_test(req)) { req->io_task_work.func = io_free_req_work; io_req_task_work_add(req, false); } } static unsigned io_cqring_events(struct io_ring_ctx *ctx) { /* See comment at the top of this file */ smp_rmb(); return __io_cqring_events(ctx); } static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* make sure SQ entry isn't read before tail */ return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head; } static inline bool io_run_task_work(void) { if (test_thread_flag(TIF_NOTIFY_SIGNAL) || task_work_pending(current)) { __set_current_state(TASK_RUNNING); clear_notify_signal(); if (task_work_pending(current)) task_work_run(); return true; } return false; } static int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) { struct io_wq_work_node *pos, *start, *prev; unsigned int poll_flags = BLK_POLL_NOSLEEP; DEFINE_IO_COMP_BATCH(iob); int nr_events = 0; /* * Only spin for completions if we don't have multiple devices hanging * off our complete list. */ if (ctx->poll_multi_queue || force_nonspin) poll_flags |= BLK_POLL_ONESHOT; wq_list_for_each(pos, start, &ctx->iopoll_list) { struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); struct kiocb *kiocb = &req->rw.kiocb; int ret; /* * Move completed and retryable entries to our local lists. * If we find a request that requires polling, break out * and complete those lists first, if we have entries there. */ if (READ_ONCE(req->iopoll_completed)) break; ret = kiocb->ki_filp->f_op->iopoll(kiocb, &iob, poll_flags); if (unlikely(ret < 0)) return ret; else if (ret) poll_flags |= BLK_POLL_ONESHOT; /* iopoll may have completed current req */ if (!rq_list_empty(iob.req_list) || READ_ONCE(req->iopoll_completed)) break; } if (!rq_list_empty(iob.req_list)) iob.complete(&iob); else if (!pos) return 0; prev = start; wq_list_for_each_resume(pos, prev) { struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); /* order with io_complete_rw_iopoll(), e.g. ->result updates */ if (!smp_load_acquire(&req->iopoll_completed)) break; if (unlikely(req->flags & REQ_F_CQE_SKIP)) continue; __io_fill_cqe_req(req, req->result, io_put_kbuf(req, 0)); nr_events++; } if (unlikely(!nr_events)) return 0; io_commit_cqring(ctx); io_cqring_ev_posted_iopoll(ctx); pos = start ? start->next : ctx->iopoll_list.first; wq_list_cut(&ctx->iopoll_list, prev, start); io_free_batch_list(ctx, pos); return nr_events; } /* * We can't just wait for polled events to come to us, we have to actively * find and complete them. */ static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx) { if (!(ctx->flags & IORING_SETUP_IOPOLL)) return; mutex_lock(&ctx->uring_lock); while (!wq_list_empty(&ctx->iopoll_list)) { /* let it sleep and repeat later if can't complete a request */ if (io_do_iopoll(ctx, true) == 0) break; /* * Ensure we allow local-to-the-cpu processing to take place, * in this case we need to ensure that we reap all events. * Also let task_work, etc. to progress by releasing the mutex */ if (need_resched()) { mutex_unlock(&ctx->uring_lock); cond_resched(); mutex_lock(&ctx->uring_lock); } } mutex_unlock(&ctx->uring_lock); } static int io_iopoll_check(struct io_ring_ctx *ctx, long min) { unsigned int nr_events = 0; int ret = 0; /* * We disallow the app entering submit/complete with polling, but we * still need to lock the ring to prevent racing with polled issue * that got punted to a workqueue. */ mutex_lock(&ctx->uring_lock); /* * Don't enter poll loop if we already have events pending. * If we do, we can potentially be spinning for commands that * already triggered a CQE (eg in error). */ if (test_bit(0, &ctx->check_cq_overflow)) __io_cqring_overflow_flush(ctx, false); if (io_cqring_events(ctx)) goto out; do { /* * If a submit got punted to a workqueue, we can have the * application entering polling for a command before it gets * issued. That app will hold the uring_lock for the duration * of the poll right here, so we need to take a breather every * now and then to ensure that the issue has a chance to add * the poll to the issued list. Otherwise we can spin here * forever, while the workqueue is stuck trying to acquire the * very same mutex. */ if (wq_list_empty(&ctx->iopoll_list)) { u32 tail = ctx->cached_cq_tail; mutex_unlock(&ctx->uring_lock); io_run_task_work(); mutex_lock(&ctx->uring_lock); /* some requests don't go through iopoll_list */ if (tail != ctx->cached_cq_tail || wq_list_empty(&ctx->iopoll_list)) break; } ret = io_do_iopoll(ctx, !min); if (ret < 0) break; nr_events += ret; ret = 0; } while (nr_events < min && !need_resched()); out: mutex_unlock(&ctx->uring_lock); return ret; } static void kiocb_end_write(struct io_kiocb *req) { /* * Tell lockdep we inherited freeze protection from submission * thread. */ if (req->flags & REQ_F_ISREG) { struct super_block *sb = file_inode(req->file)->i_sb; __sb_writers_acquired(sb, SB_FREEZE_WRITE); sb_end_write(sb); } } #ifdef CONFIG_BLOCK static bool io_resubmit_prep(struct io_kiocb *req) { struct io_async_rw *rw = req->async_data; if (!req_has_async_data(req)) return !io_req_prep_async(req); iov_iter_restore(&rw->s.iter, &rw->s.iter_state); return true; } static bool io_rw_should_reissue(struct io_kiocb *req) { umode_t mode = file_inode(req->file)->i_mode; struct io_ring_ctx *ctx = req->ctx; if (!S_ISBLK(mode) && !S_ISREG(mode)) return false; if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() && !(ctx->flags & IORING_SETUP_IOPOLL))) return false; /* * If ref is dying, we might be running poll reap from the exit work. * Don't attempt to reissue from that path, just let it fail with * -EAGAIN. */ if (percpu_ref_is_dying(&ctx->refs)) return false; /* * Play it safe and assume not safe to re-import and reissue if we're * not in the original thread group (or in task context). */ if (!same_thread_group(req->task, current) || !in_task()) return false; return true; } #else static bool io_resubmit_prep(struct io_kiocb *req) { return false; } static bool io_rw_should_reissue(struct io_kiocb *req) { return false; } #endif static bool __io_complete_rw_common(struct io_kiocb *req, long res) { if (req->rw.kiocb.ki_flags & IOCB_WRITE) { kiocb_end_write(req); fsnotify_modify(req->file); } else { fsnotify_access(req->file); } if (unlikely(res != req->result)) { if ((res == -EAGAIN || res == -EOPNOTSUPP) && io_rw_should_reissue(req)) { req->flags |= REQ_F_REISSUE; return true; } req_set_fail(req); req->result = res; } return false; } static inline void io_req_task_complete(struct io_kiocb *req, bool *locked) { int res = req->result; if (*locked) { io_req_complete_state(req, res, io_put_kbuf(req, 0)); io_req_add_compl_list(req); } else { io_req_complete_post(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED)); } } static void __io_complete_rw(struct io_kiocb *req, long res, unsigned int issue_flags) { if (__io_complete_rw_common(req, res)) return; __io_req_complete(req, issue_flags, req->result, io_put_kbuf(req, issue_flags)); } static void io_complete_rw(struct kiocb *kiocb, long res) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); if (__io_complete_rw_common(req, res)) return; req->result = res; req->io_task_work.func = io_req_task_complete; io_req_task_work_add(req, !!(req->ctx->flags & IORING_SETUP_SQPOLL)); } static void io_complete_rw_iopoll(struct kiocb *kiocb, long res) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); if (unlikely(res != req->result)) { if (res == -EAGAIN && io_rw_should_reissue(req)) { req->flags |= REQ_F_REISSUE; return; } req->result = res; } /* order with io_iopoll_complete() checking ->iopoll_completed */ smp_store_release(&req->iopoll_completed, 1); } /* * After the iocb has been issued, it's safe to be found on the poll list. * Adding the kiocb to the list AFTER submission ensures that we don't * find it from a io_do_iopoll() thread before the issuer is done * accessing the kiocb cookie. */ static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; /* workqueue context doesn't hold uring_lock, grab it now */ if (unlikely(needs_lock)) mutex_lock(&ctx->uring_lock); /* * Track whether we have multiple files in our lists. This will impact * how we do polling eventually, not spinning if we're on potentially * different devices. */ if (wq_list_empty(&ctx->iopoll_list)) { ctx->poll_multi_queue = false; } else if (!ctx->poll_multi_queue) { struct io_kiocb *list_req; list_req = container_of(ctx->iopoll_list.first, struct io_kiocb, comp_list); if (list_req->file != req->file) ctx->poll_multi_queue = true; } /* * For fast devices, IO may have already completed. If it has, add * it to the front so we find it first. */ if (READ_ONCE(req->iopoll_completed)) wq_list_add_head(&req->comp_list, &ctx->iopoll_list); else wq_list_add_tail(&req->comp_list, &ctx->iopoll_list); if (unlikely(needs_lock)) { /* * If IORING_SETUP_SQPOLL is enabled, sqes are either handle * in sq thread task context or in io worker task context. If * current task context is sq thread, we don't need to check * whether should wake up sq thread. */ if ((ctx->flags & IORING_SETUP_SQPOLL) && wq_has_sleeper(&ctx->sq_data->wait)) wake_up(&ctx->sq_data->wait); mutex_unlock(&ctx->uring_lock); } } static bool io_bdev_nowait(struct block_device *bdev) { return !bdev || blk_queue_nowait(bdev_get_queue(bdev)); } /* * If we tracked the file through the SCM inflight mechanism, we could support * any file. For now, just ensure that anything potentially problematic is done * inline. */ static bool __io_file_supports_nowait(struct file *file, umode_t mode) { if (S_ISBLK(mode)) { if (IS_ENABLED(CONFIG_BLOCK) && io_bdev_nowait(I_BDEV(file->f_mapping->host))) return true; return false; } if (S_ISSOCK(mode)) return true; if (S_ISREG(mode)) { if (IS_ENABLED(CONFIG_BLOCK) && io_bdev_nowait(file->f_inode->i_sb->s_bdev) && file->f_op != &io_uring_fops) return true; return false; } /* any ->read/write should understand O_NONBLOCK */ if (file->f_flags & O_NONBLOCK) return true; return file->f_mode & FMODE_NOWAIT; } /* * If we tracked the file through the SCM inflight mechanism, we could support * any file. For now, just ensure that anything potentially problematic is done * inline. */ static unsigned int io_file_get_flags(struct file *file) { umode_t mode = file_inode(file)->i_mode; unsigned int res = 0; if (S_ISREG(mode)) res |= FFS_ISREG; if (__io_file_supports_nowait(file, mode)) res |= FFS_NOWAIT; return res; } static inline bool io_file_supports_nowait(struct io_kiocb *req) { return req->flags & REQ_F_SUPPORT_NOWAIT; } static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct kiocb *kiocb = &req->rw.kiocb; unsigned ioprio; int ret; kiocb->ki_pos = READ_ONCE(sqe->off); ioprio = READ_ONCE(sqe->ioprio); if (ioprio) { ret = ioprio_check_cap(ioprio); if (ret) return ret; kiocb->ki_ioprio = ioprio; } else { kiocb->ki_ioprio = get_current_ioprio(); } req->imu = NULL; req->rw.addr = READ_ONCE(sqe->addr); req->rw.len = READ_ONCE(sqe->len); req->rw.flags = READ_ONCE(sqe->rw_flags); req->buf_index = READ_ONCE(sqe->buf_index); return 0; } static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) { switch (ret) { case -EIOCBQUEUED: break; case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: case -ERESTART_RESTARTBLOCK: /* * We can't just restart the syscall, since previously * submitted sqes may already be in progress. Just fail this * IO with EINTR. */ ret = -EINTR; fallthrough; default: kiocb->ki_complete(kiocb, ret); } } static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req) { struct kiocb *kiocb = &req->rw.kiocb; if (kiocb->ki_pos != -1) return &kiocb->ki_pos; if (!(req->file->f_mode & FMODE_STREAM)) { req->flags |= REQ_F_CUR_POS; kiocb->ki_pos = req->file->f_pos; return &kiocb->ki_pos; } kiocb->ki_pos = 0; return NULL; } static void kiocb_done(struct io_kiocb *req, ssize_t ret, unsigned int issue_flags) { struct io_async_rw *io = req->async_data; /* add previously done IO, if any */ if (req_has_async_data(req) && io->bytes_done > 0) { if (ret < 0) ret = io->bytes_done; else ret += io->bytes_done; } if (req->flags & REQ_F_CUR_POS) req->file->f_pos = req->rw.kiocb.ki_pos; if (ret >= 0 && (req->rw.kiocb.ki_complete == io_complete_rw)) __io_complete_rw(req, ret, issue_flags); else io_rw_done(&req->rw.kiocb, ret); if (req->flags & REQ_F_REISSUE) { req->flags &= ~REQ_F_REISSUE; if (io_resubmit_prep(req)) io_req_task_queue_reissue(req); else io_req_task_queue_fail(req, ret); } } static int __io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter, struct io_mapped_ubuf *imu) { size_t len = req->rw.len; u64 buf_end, buf_addr = req->rw.addr; size_t offset; if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) return -EFAULT; /* not inside the mapped region */ if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end)) return -EFAULT; /* * May not be a start of buffer, set size appropriately * and advance us to the beginning. */ offset = buf_addr - imu->ubuf; iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); if (offset) { /* * Don't use iov_iter_advance() here, as it's really slow for * using the latter parts of a big fixed buffer - it iterates * over each segment manually. We can cheat a bit here, because * we know that: * * 1) it's a BVEC iter, we set it up * 2) all bvecs are PAGE_SIZE in size, except potentially the * first and last bvec * * So just find our index, and adjust the iterator afterwards. * If the offset is within the first bvec (or the whole first * bvec, just use iov_iter_advance(). This makes it easier * since we can just skip the first segment, which may not * be PAGE_SIZE aligned. */ const struct bio_vec *bvec = imu->bvec; if (offset <= bvec->bv_len) { iov_iter_advance(iter, offset); } else { unsigned long seg_skip; /* skip first vec */ offset -= bvec->bv_len; seg_skip = 1 + (offset >> PAGE_SHIFT); iter->bvec = bvec + seg_skip; iter->nr_segs -= seg_skip; iter->count -= bvec->bv_len + offset; iter->iov_offset = offset & ~PAGE_MASK; } } return 0; } static int io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter, unsigned int issue_flags) { struct io_mapped_ubuf *imu = req->imu; u16 index, buf_index = req->buf_index; if (likely(!imu)) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(buf_index >= ctx->nr_user_bufs)) return -EFAULT; io_req_set_rsrc_node(req, ctx, issue_flags); index = array_index_nospec(buf_index, ctx->nr_user_bufs); imu = READ_ONCE(ctx->user_bufs[index]); req->imu = imu; } return __io_import_fixed(req, rw, iter, imu); } static void io_ring_submit_unlock(struct io_ring_ctx *ctx, bool needs_lock) { if (needs_lock) mutex_unlock(&ctx->uring_lock); } static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock) { /* * "Normal" inline submissions always hold the uring_lock, since we * grab it from the system call. Same is true for the SQPOLL offload. * The only exception is when we've detached the request and issue it * from an async worker thread, grab the lock for that case. */ if (needs_lock) mutex_lock(&ctx->uring_lock); } static void io_buffer_add_list(struct io_ring_ctx *ctx, struct io_buffer_list *bl, unsigned int bgid) { struct list_head *list; list = &ctx->io_buffers[hash_32(bgid, IO_BUFFERS_HASH_BITS)]; INIT_LIST_HEAD(&bl->buf_list); bl->bgid = bgid; list_add(&bl->list, list); } static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len, int bgid, unsigned int issue_flags) { struct io_buffer *kbuf = req->kbuf; bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; if (req->flags & REQ_F_BUFFER_SELECTED) return kbuf; io_ring_submit_lock(ctx, needs_lock); lockdep_assert_held(&ctx->uring_lock); bl = io_buffer_get_list(ctx, bgid); if (bl && !list_empty(&bl->buf_list)) { kbuf = list_first_entry(&bl->buf_list, struct io_buffer, list); list_del(&kbuf->list); if (*len > kbuf->len) *len = kbuf->len; req->flags |= REQ_F_BUFFER_SELECTED; req->kbuf = kbuf; } else { kbuf = ERR_PTR(-ENOBUFS); } io_ring_submit_unlock(req->ctx, needs_lock); return kbuf; } static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len, unsigned int issue_flags) { struct io_buffer *kbuf; u16 bgid; bgid = req->buf_index; kbuf = io_buffer_select(req, len, bgid, issue_flags); if (IS_ERR(kbuf)) return kbuf; return u64_to_user_ptr(kbuf->addr); } #ifdef CONFIG_COMPAT static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov, unsigned int issue_flags) { struct compat_iovec __user *uiov; compat_ssize_t clen; void __user *buf; ssize_t len; uiov = u64_to_user_ptr(req->rw.addr); if (!access_ok(uiov, sizeof(*uiov))) return -EFAULT; if (__get_user(clen, &uiov->iov_len)) return -EFAULT; if (clen < 0) return -EINVAL; len = clen; buf = io_rw_buffer_select(req, &len, issue_flags); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; iov[0].iov_len = (compat_size_t) len; return 0; } #endif static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, unsigned int issue_flags) { struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr); void __user *buf; ssize_t len; if (copy_from_user(iov, uiov, sizeof(*uiov))) return -EFAULT; len = iov[0].iov_len; if (len < 0) return -EINVAL; buf = io_rw_buffer_select(req, &len, issue_flags); if (IS_ERR(buf)) return PTR_ERR(buf); iov[0].iov_base = buf; iov[0].iov_len = len; return 0; } static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov, unsigned int issue_flags) { if (req->flags & REQ_F_BUFFER_SELECTED) { struct io_buffer *kbuf = req->kbuf; iov[0].iov_base = u64_to_user_ptr(kbuf->addr); iov[0].iov_len = kbuf->len; return 0; } if (req->rw.len != 1) return -EINVAL; #ifdef CONFIG_COMPAT if (req->ctx->compat) return io_compat_import(req, iov, issue_flags); #endif return __io_iov_buffer_select(req, iov, issue_flags); } static struct iovec *__io_import_iovec(int rw, struct io_kiocb *req, struct io_rw_state *s, unsigned int issue_flags) { struct iov_iter *iter = &s->iter; u8 opcode = req->opcode; struct iovec *iovec; void __user *buf; size_t sqe_len; ssize_t ret; if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { ret = io_import_fixed(req, rw, iter, issue_flags); if (ret) return ERR_PTR(ret); return NULL; } /* buffer index only valid with fixed read/write, or buffer select */ if (unlikely(req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT))) return ERR_PTR(-EINVAL); buf = u64_to_user_ptr(req->rw.addr); sqe_len = req->rw.len; if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) { if (req->flags & REQ_F_BUFFER_SELECT) { buf = io_rw_buffer_select(req, &sqe_len, issue_flags); if (IS_ERR(buf)) return ERR_CAST(buf); req->rw.len = sqe_len; } ret = import_single_range(rw, buf, sqe_len, s->fast_iov, iter); if (ret) return ERR_PTR(ret); return NULL; } iovec = s->fast_iov; if (req->flags & REQ_F_BUFFER_SELECT) { ret = io_iov_buffer_select(req, iovec, issue_flags); if (ret) return ERR_PTR(ret); iov_iter_init(iter, rw, iovec, 1, iovec->iov_len); return NULL; } ret = __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, &iovec, iter, req->ctx->compat); if (unlikely(ret < 0)) return ERR_PTR(ret); return iovec; } static inline int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct io_rw_state *s, unsigned int issue_flags) { *iovec = __io_import_iovec(rw, req, s, issue_flags); if (unlikely(IS_ERR(*iovec))) return PTR_ERR(*iovec); iov_iter_save_state(&s->iter, &s->iter_state); return 0; } static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb) { return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos; } /* * For files that don't have ->read_iter() and ->write_iter(), handle them * by looping over ->read() or ->write() manually. */ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter) { struct kiocb *kiocb = &req->rw.kiocb; struct file *file = req->file; ssize_t ret = 0; loff_t *ppos; /* * Don't support polled IO through this interface, and we can't * support non-blocking either. For the latter, this just causes * the kiocb to be handled from an async context. */ if (kiocb->ki_flags & IOCB_HIPRI) return -EOPNOTSUPP; if ((kiocb->ki_flags & IOCB_NOWAIT) && !(kiocb->ki_filp->f_flags & O_NONBLOCK)) return -EAGAIN; ppos = io_kiocb_ppos(kiocb); while (iov_iter_count(iter)) { struct iovec iovec; ssize_t nr; if (!iov_iter_is_bvec(iter)) { iovec = iov_iter_iovec(iter); } else { iovec.iov_base = u64_to_user_ptr(req->rw.addr); iovec.iov_len = req->rw.len; } if (rw == READ) { nr = file->f_op->read(file, iovec.iov_base, iovec.iov_len, ppos); } else { nr = file->f_op->write(file, iovec.iov_base, iovec.iov_len, ppos); } if (nr < 0) { if (!ret) ret = nr; break; } ret += nr; if (!iov_iter_is_bvec(iter)) { iov_iter_advance(iter, nr); } else { req->rw.addr += nr; req->rw.len -= nr; if (!req->rw.len) break; } if (nr != iovec.iov_len) break; } return ret; } static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter) { struct io_async_rw *rw = req->async_data; memcpy(&rw->s.iter, iter, sizeof(*iter)); rw->free_iovec = iovec; rw->bytes_done = 0; /* can only be fixed buffers, no need to do anything */ if (iov_iter_is_bvec(iter)) return; if (!iovec) { unsigned iov_off = 0; rw->s.iter.iov = rw->s.fast_iov; if (iter->iov != fast_iov) { iov_off = iter->iov - fast_iov; rw->s.iter.iov += iov_off; } if (rw->s.fast_iov != fast_iov) memcpy(rw->s.fast_iov + iov_off, fast_iov + iov_off, sizeof(struct iovec) * iter->nr_segs); } else { req->flags |= REQ_F_NEED_CLEANUP; } } static inline bool io_alloc_async_data(struct io_kiocb *req) { WARN_ON_ONCE(!io_op_defs[req->opcode].async_size); req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL); if (req->async_data) { req->flags |= REQ_F_ASYNC_DATA; return false; } return true; } static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, struct io_rw_state *s, bool force) { if (!force && !io_op_defs[req->opcode].needs_async_setup) return 0; if (!req_has_async_data(req)) { struct io_async_rw *iorw; if (io_alloc_async_data(req)) { kfree(iovec); return -ENOMEM; } io_req_map_rw(req, iovec, s->fast_iov, &s->iter); iorw = req->async_data; /* we've copied and mapped the iter, ensure state is saved */ iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state); } return 0; } static inline int io_rw_prep_async(struct io_kiocb *req, int rw) { struct io_async_rw *iorw = req->async_data; struct iovec *iov; int ret; /* submission path, ->uring_lock should already be taken */ ret = io_import_iovec(rw, req, &iov, &iorw->s, 0); if (unlikely(ret < 0)) return ret; iorw->bytes_done = 0; iorw->free_iovec = iov; if (iov) req->flags |= REQ_F_NEED_CLEANUP; return 0; } /* * This is our waitqueue callback handler, registered through __folio_lock_async() * when we initially tried to do the IO with the iocb armed our waitqueue. * This gets called when the page is unlocked, and we generally expect that to * happen when the page IO is completed and the page is now uptodate. This will * queue a task_work based retry of the operation, attempting to copy the data * again. If the latter fails because the page was NOT uptodate, then we will * do a thread based blocking retry of the operation. That's the unexpected * slow path. */ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, int sync, void *arg) { struct wait_page_queue *wpq; struct io_kiocb *req = wait->private; struct wait_page_key *key = arg; wpq = container_of(wait, struct wait_page_queue, wait); if (!wake_page_match(wpq, key)) return 0; req->rw.kiocb.ki_flags &= ~IOCB_WAITQ; list_del_init(&wait->entry); io_req_task_queue(req); return 1; } /* * This controls whether a given IO request should be armed for async page * based retry. If we return false here, the request is handed to the async * worker threads for retry. If we're doing buffered reads on a regular file, * we prepare a private wait_page_queue entry and retry the operation. This * will either succeed because the page is now uptodate and unlocked, or it * will register a callback when the page is unlocked at IO completion. Through * that callback, io_uring uses task_work to setup a retry of the operation. * That retry will attempt the buffered read again. The retry will generally * succeed, or in rare cases where it fails, we then fall back to using the * async worker threads for a blocking retry. */ static bool io_rw_should_retry(struct io_kiocb *req) { struct io_async_rw *rw = req->async_data; struct wait_page_queue *wait = &rw->wpq; struct kiocb *kiocb = &req->rw.kiocb; /* never retry for NOWAIT, we just complete with -EAGAIN */ if (req->flags & REQ_F_NOWAIT) return false; /* Only for buffered IO */ if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI)) return false; /* * just use poll if we can, and don't attempt if the fs doesn't * support callback based unlocks */ if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC)) return false; wait->wait.func = io_async_buf_func; wait->wait.private = req; wait->wait.flags = 0; INIT_LIST_HEAD(&wait->wait.entry); kiocb->ki_flags |= IOCB_WAITQ; kiocb->ki_flags &= ~IOCB_NOWAIT; kiocb->ki_waitq = wait; return true; } static inline int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter) { if (likely(req->file->f_op->read_iter)) return call_read_iter(req->file, &req->rw.kiocb, iter); else if (req->file->f_op->read) return loop_rw_iter(READ, req, iter); else return -EINVAL; } static bool need_read_all(struct io_kiocb *req) { return req->flags & REQ_F_ISREG || S_ISBLK(file_inode(req->file)->i_mode); } static int io_rw_init_file(struct io_kiocb *req, fmode_t mode) { struct kiocb *kiocb = &req->rw.kiocb; struct io_ring_ctx *ctx = req->ctx; struct file *file = req->file; int ret; if (unlikely(!file || !(file->f_mode & mode))) return -EBADF; if (!io_req_ffs_set(req)) req->flags |= io_file_get_flags(file) << REQ_F_SUPPORT_NOWAIT_BIT; kiocb->ki_flags = iocb_flags(file); ret = kiocb_set_rw_flags(kiocb, req->rw.flags); if (unlikely(ret)) return ret; /* * If the file is marked O_NONBLOCK, still allow retry for it if it * supports async. Otherwise it's impossible to use O_NONBLOCK files * reliably. If not, or it IOCB_NOWAIT is set, don't retry. */ if ((kiocb->ki_flags & IOCB_NOWAIT) || ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req))) req->flags |= REQ_F_NOWAIT; if (ctx->flags & IORING_SETUP_IOPOLL) { if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll) return -EOPNOTSUPP; kiocb->ki_flags |= IOCB_HIPRI | IOCB_ALLOC_CACHE; kiocb->ki_complete = io_complete_rw_iopoll; req->iopoll_completed = 0; } else { if (kiocb->ki_flags & IOCB_HIPRI) return -EINVAL; kiocb->ki_complete = io_complete_rw; } return 0; } static int io_read(struct io_kiocb *req, unsigned int issue_flags) { struct io_rw_state __s, *s = &__s; struct iovec *iovec; struct kiocb *kiocb = &req->rw.kiocb; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; struct io_async_rw *rw; ssize_t ret, ret2; loff_t *ppos; if (!req_has_async_data(req)) { ret = io_import_iovec(READ, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; } else { /* * Safe and required to re-import if we're using provided * buffers, as we dropped the selected one before retry. */ if (req->flags & REQ_F_BUFFER_SELECT) { ret = io_import_iovec(READ, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; } rw = req->async_data; s = &rw->s; /* * We come here from an earlier attempt, restore our state to * match in case it doesn't. It's cheap enough that we don't * need to make this conditional. */ iov_iter_restore(&s->iter, &s->iter_state); iovec = NULL; } ret = io_rw_init_file(req, FMODE_READ); if (unlikely(ret)) return ret; req->result = iov_iter_count(&s->iter); if (force_nonblock) { /* If the file doesn't support async, just async punt */ if (unlikely(!io_file_supports_nowait(req))) { ret = io_setup_async_rw(req, iovec, s, true); return ret ?: -EAGAIN; } kiocb->ki_flags |= IOCB_NOWAIT; } else { /* Ensure we clear previously set non-block flag */ kiocb->ki_flags &= ~IOCB_NOWAIT; } ppos = io_kiocb_update_pos(req); ret = rw_verify_area(READ, req->file, ppos, req->result); if (unlikely(ret)) { kfree(iovec); return ret; } ret = io_iter_do_read(req, &s->iter); if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { req->flags &= ~REQ_F_REISSUE; /* if we can poll, just do that */ if (req->opcode == IORING_OP_READ && file_can_poll(req->file)) return -EAGAIN; /* IOPOLL retry should happen for io-wq threads */ if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) goto done; /* no retry on NONBLOCK nor RWF_NOWAIT */ if (req->flags & REQ_F_NOWAIT) goto done; ret = 0; } else if (ret == -EIOCBQUEUED) { goto out_free; } else if (ret == req->result || ret <= 0 || !force_nonblock || (req->flags & REQ_F_NOWAIT) || !need_read_all(req)) { /* read all, failed, already did sync or don't want to retry */ goto done; } /* * Don't depend on the iter state matching what was consumed, or being * untouched in case of error. Restore it and we'll advance it * manually if we need to. */ iov_iter_restore(&s->iter, &s->iter_state); ret2 = io_setup_async_rw(req, iovec, s, true); if (ret2) return ret2; iovec = NULL; rw = req->async_data; s = &rw->s; /* * Now use our persistent iterator and state, if we aren't already. * We've restored and mapped the iter to match. */ do { /* * We end up here because of a partial read, either from * above or inside this loop. Advance the iter by the bytes * that were consumed. */ iov_iter_advance(&s->iter, ret); if (!iov_iter_count(&s->iter)) break; rw->bytes_done += ret; iov_iter_save_state(&s->iter, &s->iter_state); /* if we can retry, do so with the callbacks armed */ if (!io_rw_should_retry(req)) { kiocb->ki_flags &= ~IOCB_WAITQ; return -EAGAIN; } /* * Now retry read with the IOCB_WAITQ parts set in the iocb. If * we get -EIOCBQUEUED, then we'll get a notification when the * desired page gets unlocked. We can also get a partial read * here, and if we do, then just retry at the new offset. */ ret = io_iter_do_read(req, &s->iter); if (ret == -EIOCBQUEUED) return 0; /* we got some bytes, but not all. retry. */ kiocb->ki_flags &= ~IOCB_WAITQ; iov_iter_restore(&s->iter, &s->iter_state); } while (ret > 0); done: kiocb_done(req, ret, issue_flags); out_free: /* it's faster to check here then delegate to kfree */ if (iovec) kfree(iovec); return 0; } static int io_write(struct io_kiocb *req, unsigned int issue_flags) { struct io_rw_state __s, *s = &__s; struct iovec *iovec; struct kiocb *kiocb = &req->rw.kiocb; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; ssize_t ret, ret2; loff_t *ppos; if (!req_has_async_data(req)) { ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; } else { struct io_async_rw *rw = req->async_data; s = &rw->s; iov_iter_restore(&s->iter, &s->iter_state); iovec = NULL; } ret = io_rw_init_file(req, FMODE_WRITE); if (unlikely(ret)) return ret; req->result = iov_iter_count(&s->iter); if (force_nonblock) { /* If the file doesn't support async, just async punt */ if (unlikely(!io_file_supports_nowait(req))) goto copy_iov; /* file path doesn't support NOWAIT for non-direct_IO */ if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) && (req->flags & REQ_F_ISREG)) goto copy_iov; kiocb->ki_flags |= IOCB_NOWAIT; } else { /* Ensure we clear previously set non-block flag */ kiocb->ki_flags &= ~IOCB_NOWAIT; } ppos = io_kiocb_update_pos(req); ret = rw_verify_area(WRITE, req->file, ppos, req->result); if (unlikely(ret)) goto out_free; /* * Open-code file_start_write here to grab freeze protection, * which will be released by another thread in * io_complete_rw(). Fool lockdep by telling it the lock got * released so that it doesn't complain about the held lock when * we return to userspace. */ if (req->flags & REQ_F_ISREG) { sb_start_write(file_inode(req->file)->i_sb); __sb_writers_release(file_inode(req->file)->i_sb, SB_FREEZE_WRITE); } kiocb->ki_flags |= IOCB_WRITE; if (likely(req->file->f_op->write_iter)) ret2 = call_write_iter(req->file, kiocb, &s->iter); else if (req->file->f_op->write) ret2 = loop_rw_iter(WRITE, req, &s->iter); else ret2 = -EINVAL; if (req->flags & REQ_F_REISSUE) { req->flags &= ~REQ_F_REISSUE; ret2 = -EAGAIN; } /* * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just * retry them without IOCB_NOWAIT. */ if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) ret2 = -EAGAIN; /* no retry on NONBLOCK nor RWF_NOWAIT */ if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) goto done; if (!force_nonblock || ret2 != -EAGAIN) { /* IOPOLL retry should happen for io-wq threads */ if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL)) goto copy_iov; done: kiocb_done(req, ret2, issue_flags); } else { copy_iov: iov_iter_restore(&s->iter, &s->iter_state); ret = io_setup_async_rw(req, iovec, s, false); return ret ?: -EAGAIN; } out_free: /* it's reportedly faster than delegating the null check to kfree() */ if (iovec) kfree(iovec); return ret; } static int io_renameat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_rename *ren = &req->rename; const char __user *oldf, *newf; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; ren->old_dfd = READ_ONCE(sqe->fd); oldf = u64_to_user_ptr(READ_ONCE(sqe->addr)); newf = u64_to_user_ptr(READ_ONCE(sqe->addr2)); ren->new_dfd = READ_ONCE(sqe->len); ren->flags = READ_ONCE(sqe->rename_flags); ren->oldpath = getname(oldf); if (IS_ERR(ren->oldpath)) return PTR_ERR(ren->oldpath); ren->newpath = getname(newf); if (IS_ERR(ren->newpath)) { putname(ren->oldpath); return PTR_ERR(ren->newpath); } req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_renameat(struct io_kiocb *req, unsigned int issue_flags) { struct io_rename *ren = &req->rename; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_renameat2(ren->old_dfd, ren->oldpath, ren->new_dfd, ren->newpath, ren->flags); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_unlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_unlink *un = &req->unlink; const char __user *fname; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; un->dfd = READ_ONCE(sqe->fd); un->flags = READ_ONCE(sqe->unlink_flags); if (un->flags & ~AT_REMOVEDIR) return -EINVAL; fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); un->filename = getname(fname); if (IS_ERR(un->filename)) return PTR_ERR(un->filename); req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_unlinkat(struct io_kiocb *req, unsigned int issue_flags) { struct io_unlink *un = &req->unlink; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; if (un->flags & AT_REMOVEDIR) ret = do_rmdir(un->dfd, un->filename); else ret = do_unlinkat(un->dfd, un->filename); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_mkdirat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_mkdir *mkd = &req->mkdir; const char __user *fname; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; mkd->dfd = READ_ONCE(sqe->fd); mkd->mode = READ_ONCE(sqe->len); fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); mkd->filename = getname(fname); if (IS_ERR(mkd->filename)) return PTR_ERR(mkd->filename); req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_mkdirat(struct io_kiocb *req, unsigned int issue_flags) { struct io_mkdir *mkd = &req->mkdir; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_mkdirat(mkd->dfd, mkd->filename, mkd->mode); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_symlinkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_symlink *sl = &req->symlink; const char __user *oldpath, *newpath; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; sl->new_dfd = READ_ONCE(sqe->fd); oldpath = u64_to_user_ptr(READ_ONCE(sqe->addr)); newpath = u64_to_user_ptr(READ_ONCE(sqe->addr2)); sl->oldpath = getname(oldpath); if (IS_ERR(sl->oldpath)) return PTR_ERR(sl->oldpath); sl->newpath = getname(newpath); if (IS_ERR(sl->newpath)) { putname(sl->oldpath); return PTR_ERR(sl->newpath); } req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_symlinkat(struct io_kiocb *req, unsigned int issue_flags) { struct io_symlink *sl = &req->symlink; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_symlinkat(sl->oldpath, sl->new_dfd, sl->newpath); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_linkat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_hardlink *lnk = &req->hardlink; const char __user *oldf, *newf; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; lnk->old_dfd = READ_ONCE(sqe->fd); lnk->new_dfd = READ_ONCE(sqe->len); oldf = u64_to_user_ptr(READ_ONCE(sqe->addr)); newf = u64_to_user_ptr(READ_ONCE(sqe->addr2)); lnk->flags = READ_ONCE(sqe->hardlink_flags); lnk->oldpath = getname(oldf); if (IS_ERR(lnk->oldpath)) return PTR_ERR(lnk->oldpath); lnk->newpath = getname(newf); if (IS_ERR(lnk->newpath)) { putname(lnk->oldpath); return PTR_ERR(lnk->newpath); } req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_linkat(struct io_kiocb *req, unsigned int issue_flags) { struct io_hardlink *lnk = &req->hardlink; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_linkat(lnk->old_dfd, lnk->oldpath, lnk->new_dfd, lnk->newpath, lnk->flags); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_shutdown_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_NET) if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->ioprio || sqe->off || sqe->addr || sqe->rw_flags || sqe->buf_index || sqe->splice_fd_in)) return -EINVAL; req->shutdown.how = READ_ONCE(sqe->len); return 0; #else return -EOPNOTSUPP; #endif } static int io_shutdown(struct io_kiocb *req, unsigned int issue_flags) { #if defined(CONFIG_NET) struct socket *sock; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; ret = __sys_shutdown_sock(sock, req->shutdown.how); if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; #else return -EOPNOTSUPP; #endif } static int __io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_splice *sp = &req->splice; unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sp->len = READ_ONCE(sqe->len); sp->flags = READ_ONCE(sqe->splice_flags); if (unlikely(sp->flags & ~valid_flags)) return -EINVAL; sp->splice_fd_in = READ_ONCE(sqe->splice_fd_in); return 0; } static int io_tee_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off)) return -EINVAL; return __io_splice_prep(req, sqe); } static int io_tee(struct io_kiocb *req, unsigned int issue_flags) { struct io_splice *sp = &req->splice; struct file *out = sp->file_out; unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED; struct file *in; long ret = 0; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; if (sp->flags & SPLICE_F_FD_IN_FIXED) in = io_file_get_fixed(req, sp->splice_fd_in, IO_URING_F_UNLOCKED); else in = io_file_get_normal(req, sp->splice_fd_in); if (!in) { ret = -EBADF; goto done; } if (sp->len) ret = do_tee(in, out, sp->len, flags); if (!(sp->flags & SPLICE_F_FD_IN_FIXED)) io_put_file(in); done: if (ret != sp->len) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_splice *sp = &req->splice; sp->off_in = READ_ONCE(sqe->splice_off_in); sp->off_out = READ_ONCE(sqe->off); return __io_splice_prep(req, sqe); } static int io_splice(struct io_kiocb *req, unsigned int issue_flags) { struct io_splice *sp = &req->splice; struct file *out = sp->file_out; unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED; loff_t *poff_in, *poff_out; struct file *in; long ret = 0; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; if (sp->flags & SPLICE_F_FD_IN_FIXED) in = io_file_get_fixed(req, sp->splice_fd_in, IO_URING_F_UNLOCKED); else in = io_file_get_normal(req, sp->splice_fd_in); if (!in) { ret = -EBADF; goto done; } poff_in = (sp->off_in == -1) ? NULL : &sp->off_in; poff_out = (sp->off_out == -1) ? NULL : &sp->off_out; if (sp->len) ret = do_splice(in, poff_in, out, poff_out, sp->len, flags); if (!(sp->flags & SPLICE_F_FD_IN_FIXED)) io_put_file(in); done: if (ret != sp->len) req_set_fail(req); io_req_complete(req, ret); return 0; } /* * IORING_OP_NOP just posts a completion event, nothing else. */ static int io_nop(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; __io_req_complete(req, issue_flags, 0, 0); return 0; } static int io_msg_ring_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(sqe->addr || sqe->ioprio || sqe->rw_flags || sqe->splice_fd_in || sqe->buf_index || sqe->personality)) return -EINVAL; req->msg.user_data = READ_ONCE(sqe->off); req->msg.len = READ_ONCE(sqe->len); return 0; } static int io_msg_ring(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *target_ctx; struct io_msg *msg = &req->msg; bool filled; int ret; ret = -EBADFD; if (req->file->f_op != &io_uring_fops) goto done; ret = -EOVERFLOW; target_ctx = req->file->private_data; spin_lock(&target_ctx->completion_lock); filled = io_fill_cqe_aux(target_ctx, msg->user_data, msg->len, 0); io_commit_cqring(target_ctx); spin_unlock(&target_ctx->completion_lock); if (filled) { io_cqring_ev_posted(target_ctx); ret = 0; } done: if (ret < 0) req_set_fail(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_fsync_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index || sqe->splice_fd_in)) return -EINVAL; req->sync.flags = READ_ONCE(sqe->fsync_flags); if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); return 0; } static int io_fsync(struct io_kiocb *req, unsigned int issue_flags) { loff_t end = req->sync.off + req->sync.len; int ret; /* fsync always requires a blocking context */ if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = vfs_fsync_range(req->file, req->sync.off, end > 0 ? end : LLONG_MAX, req->sync.flags & IORING_FSYNC_DATASYNC); if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->addr); req->sync.mode = READ_ONCE(sqe->len); return 0; } static int io_fallocate(struct io_kiocb *req, unsigned int issue_flags) { int ret; /* fallocate always requiring blocking context */ if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off, req->sync.len); if (ret < 0) req_set_fail(req); else fsnotify_modify(req->file); io_req_complete(req, ret); return 0; } static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { const char __user *fname; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->ioprio || sqe->buf_index)) return -EINVAL; if (unlikely(req->flags & REQ_F_FIXED_FILE)) return -EBADF; /* open.how should be already initialised */ if (!(req->open.how.flags & O_PATH) && force_o_largefile()) req->open.how.flags |= O_LARGEFILE; req->open.dfd = READ_ONCE(sqe->fd); fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->open.filename = getname(fname); if (IS_ERR(req->open.filename)) { ret = PTR_ERR(req->open.filename); req->open.filename = NULL; return ret; } req->open.file_slot = READ_ONCE(sqe->file_index); if (req->open.file_slot && (req->open.how.flags & O_CLOEXEC)) return -EINVAL; req->open.nofile = rlimit(RLIMIT_NOFILE); req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { u64 mode = READ_ONCE(sqe->len); u64 flags = READ_ONCE(sqe->open_flags); req->open.how = build_open_how(flags, mode); return __io_openat_prep(req, sqe); } static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct open_how __user *how; size_t len; int ret; how = u64_to_user_ptr(READ_ONCE(sqe->addr2)); len = READ_ONCE(sqe->len); if (len < OPEN_HOW_SIZE_VER0) return -EINVAL; ret = copy_struct_from_user(&req->open.how, sizeof(req->open.how), how, len); if (ret) return ret; return __io_openat_prep(req, sqe); } static int io_openat2(struct io_kiocb *req, unsigned int issue_flags) { struct open_flags op; struct file *file; bool resolve_nonblock, nonblock_set; bool fixed = !!req->open.file_slot; int ret; ret = build_open_flags(&req->open.how, &op); if (ret) goto err; nonblock_set = op.open_flag & O_NONBLOCK; resolve_nonblock = req->open.how.resolve & RESOLVE_CACHED; if (issue_flags & IO_URING_F_NONBLOCK) { /* * Don't bother trying for O_TRUNC, O_CREAT, or O_TMPFILE open, * it'll always -EAGAIN */ if (req->open.how.flags & (O_TRUNC | O_CREAT | O_TMPFILE)) return -EAGAIN; op.lookup_flags |= LOOKUP_CACHED; op.open_flag |= O_NONBLOCK; } if (!fixed) { ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile); if (ret < 0) goto err; } file = do_filp_open(req->open.dfd, req->open.filename, &op); if (IS_ERR(file)) { /* * We could hang on to this 'fd' on retrying, but seems like * marginal gain for something that is now known to be a slower * path. So just put it, and we'll get a new one when we retry. */ if (!fixed) put_unused_fd(ret); ret = PTR_ERR(file); /* only retry if RESOLVE_CACHED wasn't already set by application */ if (ret == -EAGAIN && (!resolve_nonblock && (issue_flags & IO_URING_F_NONBLOCK))) return -EAGAIN; goto err; } if ((issue_flags & IO_URING_F_NONBLOCK) && !nonblock_set) file->f_flags &= ~O_NONBLOCK; fsnotify_open(file); if (!fixed) fd_install(ret, file); else ret = io_install_fixed_file(req, file, issue_flags, req->open.file_slot - 1); err: putname(req->open.filename); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret < 0) req_set_fail(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_openat(struct io_kiocb *req, unsigned int issue_flags) { return io_openat2(req, issue_flags); } static int io_remove_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_provide_buf *p = &req->pbuf; u64 tmp; if (sqe->ioprio || sqe->rw_flags || sqe->addr || sqe->len || sqe->off || sqe->splice_fd_in) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > USHRT_MAX) return -EINVAL; memset(p, 0, sizeof(*p)); p->nbufs = tmp; p->bgid = READ_ONCE(sqe->buf_group); return 0; } static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer_list *bl, unsigned nbufs) { unsigned i = 0; /* shouldn't happen */ if (!nbufs) return 0; /* the head kbuf is the list itself */ while (!list_empty(&bl->buf_list)) { struct io_buffer *nxt; nxt = list_first_entry(&bl->buf_list, struct io_buffer, list); list_del(&nxt->list); if (++i == nbufs) return i; cond_resched(); } i++; return i; } static int io_remove_buffers(struct io_kiocb *req, unsigned int issue_flags) { struct io_provide_buf *p = &req->pbuf; struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret = 0; bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; io_ring_submit_lock(ctx, needs_lock); lockdep_assert_held(&ctx->uring_lock); ret = -ENOENT; bl = io_buffer_get_list(ctx, p->bgid); if (bl) ret = __io_remove_buffers(ctx, bl, p->nbufs); if (ret < 0) req_set_fail(req); /* complete before unlock, IOPOLL may need the lock */ __io_req_complete(req, issue_flags, ret, 0); io_ring_submit_unlock(ctx, needs_lock); return 0; } static int io_provide_buffers_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { unsigned long size, tmp_check; struct io_provide_buf *p = &req->pbuf; u64 tmp; if (sqe->ioprio || sqe->rw_flags || sqe->splice_fd_in) return -EINVAL; tmp = READ_ONCE(sqe->fd); if (!tmp || tmp > USHRT_MAX) return -E2BIG; p->nbufs = tmp; p->addr = READ_ONCE(sqe->addr); p->len = READ_ONCE(sqe->len); if (check_mul_overflow((unsigned long)p->len, (unsigned long)p->nbufs, &size)) return -EOVERFLOW; if (check_add_overflow((unsigned long)p->addr, size, &tmp_check)) return -EOVERFLOW; size = (unsigned long)p->len * p->nbufs; if (!access_ok(u64_to_user_ptr(p->addr), size)) return -EFAULT; p->bgid = READ_ONCE(sqe->buf_group); tmp = READ_ONCE(sqe->off); if (tmp > USHRT_MAX) return -E2BIG; p->bid = tmp; return 0; } static int io_refill_buffer_cache(struct io_ring_ctx *ctx) { struct io_buffer *buf; struct page *page; int bufs_in_page; /* * Completions that don't happen inline (eg not under uring_lock) will * add to ->io_buffers_comp. If we don't have any free buffers, check * the completion list and splice those entries first. */ if (!list_empty_careful(&ctx->io_buffers_comp)) { spin_lock(&ctx->completion_lock); if (!list_empty(&ctx->io_buffers_comp)) { list_splice_init(&ctx->io_buffers_comp, &ctx->io_buffers_cache); spin_unlock(&ctx->completion_lock); return 0; } spin_unlock(&ctx->completion_lock); } /* * No free buffers and no completion entries either. Allocate a new * page worth of buffer entries and add those to our freelist. */ page = alloc_page(GFP_KERNEL_ACCOUNT); if (!page) return -ENOMEM; list_add(&page->lru, &ctx->io_buffers_pages); buf = page_address(page); bufs_in_page = PAGE_SIZE / sizeof(*buf); while (bufs_in_page) { list_add_tail(&buf->list, &ctx->io_buffers_cache); buf++; bufs_in_page--; } return 0; } static int io_add_buffers(struct io_ring_ctx *ctx, struct io_provide_buf *pbuf, struct io_buffer_list *bl) { struct io_buffer *buf; u64 addr = pbuf->addr; int i, bid = pbuf->bid; for (i = 0; i < pbuf->nbufs; i++) { if (list_empty(&ctx->io_buffers_cache) && io_refill_buffer_cache(ctx)) break; buf = list_first_entry(&ctx->io_buffers_cache, struct io_buffer, list); list_move_tail(&buf->list, &bl->buf_list); buf->addr = addr; buf->len = min_t(__u32, pbuf->len, MAX_RW_COUNT); buf->bid = bid; buf->bgid = pbuf->bgid; addr += pbuf->len; bid++; cond_resched(); } return i ? 0 : -ENOMEM; } static int io_provide_buffers(struct io_kiocb *req, unsigned int issue_flags) { struct io_provide_buf *p = &req->pbuf; struct io_ring_ctx *ctx = req->ctx; struct io_buffer_list *bl; int ret = 0; bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; io_ring_submit_lock(ctx, needs_lock); lockdep_assert_held(&ctx->uring_lock); bl = io_buffer_get_list(ctx, p->bgid); if (unlikely(!bl)) { bl = kmalloc(sizeof(*bl), GFP_KERNEL); if (!bl) { ret = -ENOMEM; goto err; } io_buffer_add_list(ctx, bl, p->bgid); } ret = io_add_buffers(ctx, p, bl); err: if (ret < 0) req_set_fail(req); /* complete before unlock, IOPOLL may need the lock */ __io_req_complete(req, issue_flags, ret, 0); io_ring_submit_unlock(ctx, needs_lock); return 0; } static int io_epoll_ctl_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_EPOLL) if (sqe->ioprio || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->epoll.epfd = READ_ONCE(sqe->fd); req->epoll.op = READ_ONCE(sqe->len); req->epoll.fd = READ_ONCE(sqe->off); if (ep_op_has_event(req->epoll.op)) { struct epoll_event __user *ev; ev = u64_to_user_ptr(READ_ONCE(sqe->addr)); if (copy_from_user(&req->epoll.event, ev, sizeof(*ev))) return -EFAULT; } return 0; #else return -EOPNOTSUPP; #endif } static int io_epoll_ctl(struct io_kiocb *req, unsigned int issue_flags) { #if defined(CONFIG_EPOLL) struct io_epoll *ie = &req->epoll; int ret; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret < 0) req_set_fail(req); __io_req_complete(req, issue_flags, ret, 0); return 0; #else return -EOPNOTSUPP; #endif } static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) if (sqe->ioprio || sqe->buf_index || sqe->off || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->madvise.addr = READ_ONCE(sqe->addr); req->madvise.len = READ_ONCE(sqe->len); req->madvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; #else return -EOPNOTSUPP; #endif } static int io_madvise(struct io_kiocb *req, unsigned int issue_flags) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) struct io_madvise *ma = &req->madvise; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice); if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; #else return -EOPNOTSUPP; #endif } static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->addr || sqe->splice_fd_in) return -EINVAL; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; req->fadvise.offset = READ_ONCE(sqe->off); req->fadvise.len = READ_ONCE(sqe->len); req->fadvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; } static int io_fadvise(struct io_kiocb *req, unsigned int issue_flags) { struct io_fadvise *fa = &req->fadvise; int ret; if (issue_flags & IO_URING_F_NONBLOCK) { switch (fa->advice) { case POSIX_FADV_NORMAL: case POSIX_FADV_RANDOM: case POSIX_FADV_SEQUENTIAL: break; default: return -EAGAIN; } } ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice); if (ret < 0) req_set_fail(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { const char __user *path; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; if (req->flags & REQ_F_FIXED_FILE) return -EBADF; req->statx.dfd = READ_ONCE(sqe->fd); req->statx.mask = READ_ONCE(sqe->len); path = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2)); req->statx.flags = READ_ONCE(sqe->statx_flags); req->statx.filename = getname_flags(path, getname_statx_lookup_flags(req->statx.flags), NULL); if (IS_ERR(req->statx.filename)) { int ret = PTR_ERR(req->statx.filename); req->statx.filename = NULL; return ret; } req->flags |= REQ_F_NEED_CLEANUP; return 0; } static int io_statx(struct io_kiocb *req, unsigned int issue_flags) { struct io_statx *ctx = &req->statx; int ret; if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask, ctx->buffer); if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index) return -EINVAL; if (req->flags & REQ_F_FIXED_FILE) return -EBADF; req->close.fd = READ_ONCE(sqe->fd); req->close.file_slot = READ_ONCE(sqe->file_index); if (req->close.file_slot && req->close.fd) return -EINVAL; return 0; } static int io_close(struct io_kiocb *req, unsigned int issue_flags) { struct files_struct *files = current->files; struct io_close *close = &req->close; struct fdtable *fdt; struct file *file = NULL; int ret = -EBADF; if (req->close.file_slot) { ret = io_close_fixed(req, issue_flags); goto err; } spin_lock(&files->file_lock); fdt = files_fdtable(files); if (close->fd >= fdt->max_fds) { spin_unlock(&files->file_lock); goto err; } file = fdt->fd[close->fd]; if (!file || file->f_op == &io_uring_fops) { spin_unlock(&files->file_lock); file = NULL; goto err; } /* if the file has a flush method, be safe and punt to async */ if (file->f_op->flush && (issue_flags & IO_URING_F_NONBLOCK)) { spin_unlock(&files->file_lock); return -EAGAIN; } ret = __close_fd_get_file(close->fd, &file); spin_unlock(&files->file_lock); if (ret < 0) { if (ret == -ENOENT) ret = -EBADF; goto err; } /* No ->flush() or already async, safely close from here */ ret = filp_close(file, current->files); err: if (ret < 0) req_set_fail(req); if (file) fput(file); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_sfr_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index || sqe->splice_fd_in)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); req->sync.flags = READ_ONCE(sqe->sync_range_flags); return 0; } static int io_sync_file_range(struct io_kiocb *req, unsigned int issue_flags) { int ret; /* sync_file_range always requires a blocking context */ if (issue_flags & IO_URING_F_NONBLOCK) return -EAGAIN; ret = sync_file_range(req->file, req->sync.off, req->sync.len, req->sync.flags); if (ret < 0) req_set_fail(req); io_req_complete(req, ret); return 0; } #if defined(CONFIG_NET) static int io_setup_async_msg(struct io_kiocb *req, struct io_async_msghdr *kmsg) { struct io_async_msghdr *async_msg = req->async_data; if (async_msg) return -EAGAIN; if (io_alloc_async_data(req)) { kfree(kmsg->free_iov); return -ENOMEM; } async_msg = req->async_data; req->flags |= REQ_F_NEED_CLEANUP; memcpy(async_msg, kmsg, sizeof(*kmsg)); async_msg->msg.msg_name = &async_msg->addr; /* if were using fast_iov, set it to the new one */ if (!async_msg->free_iov) async_msg->msg.msg_iter.iov = async_msg->fast_iov; return -EAGAIN; } static int io_sendmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { iomsg->msg.msg_name = &iomsg->addr; iomsg->free_iov = iomsg->fast_iov; return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg, req->sr_msg.msg_flags, &iomsg->free_iov); } static int io_sendmsg_prep_async(struct io_kiocb *req) { int ret; ret = io_sendmsg_copy_hdr(req, req->async_data); if (!ret) req->flags |= REQ_F_NEED_CLEANUP; return ret; } static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_sr_msg *sr = &req->sr_msg; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr)); sr->len = READ_ONCE(sqe->len); sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL; if (sr->msg_flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; #ifdef CONFIG_COMPAT if (req->ctx->compat) sr->msg_flags |= MSG_CMSG_COMPAT; #endif return 0; } static int io_sendmsg(struct io_kiocb *req, unsigned int issue_flags) { struct io_async_msghdr iomsg, *kmsg; struct socket *sock; unsigned flags; int min_ret = 0; int ret; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; if (req_has_async_data(req)) { kmsg = req->async_data; } else { ret = io_sendmsg_copy_hdr(req, &iomsg); if (ret) return ret; kmsg = &iomsg; } flags = req->sr_msg.msg_flags; if (issue_flags & IO_URING_F_NONBLOCK) flags |= MSG_DONTWAIT; if (flags & MSG_WAITALL) min_ret = iov_iter_count(&kmsg->msg.msg_iter); ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags); if (ret < min_ret) { if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK)) return io_setup_async_msg(req, kmsg); if (ret == -ERESTARTSYS) ret = -EINTR; req_set_fail(req); } /* fast path, check for non-NULL to avoid function call */ if (kmsg->free_iov) kfree(kmsg->free_iov); req->flags &= ~REQ_F_NEED_CLEANUP; __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_send(struct io_kiocb *req, unsigned int issue_flags) { struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; struct iovec iov; struct socket *sock; unsigned flags; int min_ret = 0; int ret; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter); if (unlikely(ret)) return ret; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; flags = req->sr_msg.msg_flags; if (issue_flags & IO_URING_F_NONBLOCK) flags |= MSG_DONTWAIT; if (flags & MSG_WAITALL) min_ret = iov_iter_count(&msg.msg_iter); msg.msg_flags = flags; ret = sock_sendmsg(sock, &msg); if (ret < min_ret) { if (ret == -EAGAIN && (issue_flags & IO_URING_F_NONBLOCK)) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; req_set_fail(req); } __io_req_complete(req, issue_flags, ret, 0); return 0; } static int __io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { struct io_sr_msg *sr = &req->sr_msg; struct iovec __user *uiov; size_t iov_len; int ret; ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg, &iomsg->uaddr, &uiov, &iov_len); if (ret) return ret; if (req->flags & REQ_F_BUFFER_SELECT) { if (iov_len > 1) return -EINVAL; if (copy_from_user(iomsg->fast_iov, uiov, sizeof(*uiov))) return -EFAULT; sr->len = iomsg->fast_iov[0].iov_len; iomsg->free_iov = NULL; } else { iomsg->free_iov = iomsg->fast_iov; ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV, &iomsg->free_iov, &iomsg->msg.msg_iter, false); if (ret > 0) ret = 0; } return ret; } #ifdef CONFIG_COMPAT static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { struct io_sr_msg *sr = &req->sr_msg; struct compat_iovec __user *uiov; compat_uptr_t ptr; compat_size_t len; int ret; ret = __get_compat_msghdr(&iomsg->msg, sr->umsg_compat, &iomsg->uaddr, &ptr, &len); if (ret) return ret; uiov = compat_ptr(ptr); if (req->flags & REQ_F_BUFFER_SELECT) { compat_ssize_t clen; if (len > 1) return -EINVAL; if (!access_ok(uiov, sizeof(*uiov))) return -EFAULT; if (__get_user(clen, &uiov->iov_len)) return -EFAULT; if (clen < 0) return -EINVAL; sr->len = clen; iomsg->free_iov = NULL; } else { iomsg->free_iov = iomsg->fast_iov; ret = __import_iovec(READ, (struct iovec __user *)uiov, len, UIO_FASTIOV, &iomsg->free_iov, &iomsg->msg.msg_iter, true); if (ret < 0) return ret; } return 0; } #endif static int io_recvmsg_copy_hdr(struct io_kiocb *req, struct io_async_msghdr *iomsg) { iomsg->msg.msg_name = &iomsg->addr; #ifdef CONFIG_COMPAT if (req->ctx->compat) return __io_compat_recvmsg_copy_hdr(req, iomsg); #endif return __io_recvmsg_copy_hdr(req, iomsg); } static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req, unsigned int issue_flags) { struct io_sr_msg *sr = &req->sr_msg; return io_buffer_select(req, &sr->len, sr->bgid, issue_flags); } static int io_recvmsg_prep_async(struct io_kiocb *req) { int ret; ret = io_recvmsg_copy_hdr(req, req->async_data); if (!ret) req->flags |= REQ_F_NEED_CLEANUP; return ret; } static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_sr_msg *sr = &req->sr_msg; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr)); sr->len = READ_ONCE(sqe->len); sr->bgid = READ_ONCE(sqe->buf_group); sr->msg_flags = READ_ONCE(sqe->msg_flags) | MSG_NOSIGNAL; if (sr->msg_flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; #ifdef CONFIG_COMPAT if (req->ctx->compat) sr->msg_flags |= MSG_CMSG_COMPAT; #endif sr->done_io = 0; return 0; } static bool io_net_retry(struct socket *sock, int flags) { if (!(flags & MSG_WAITALL)) return false; return sock->type == SOCK_STREAM || sock->type == SOCK_SEQPACKET; } static int io_recvmsg(struct io_kiocb *req, unsigned int issue_flags) { struct io_async_msghdr iomsg, *kmsg; struct io_sr_msg *sr = &req->sr_msg; struct socket *sock; struct io_buffer *kbuf; unsigned flags; int ret, min_ret = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; if (req_has_async_data(req)) { kmsg = req->async_data; } else { ret = io_recvmsg_copy_hdr(req, &iomsg); if (ret) return ret; kmsg = &iomsg; } if (req->flags & REQ_F_BUFFER_SELECT) { kbuf = io_recv_buffer_select(req, issue_flags); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr); kmsg->fast_iov[0].iov_len = req->sr_msg.len; iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1, req->sr_msg.len); } flags = req->sr_msg.msg_flags; if (force_nonblock) flags |= MSG_DONTWAIT; if (flags & MSG_WAITALL) min_ret = iov_iter_count(&kmsg->msg.msg_iter); ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg, kmsg->uaddr, flags); if (ret < min_ret) { if (ret == -EAGAIN && force_nonblock) return io_setup_async_msg(req, kmsg); if (ret == -ERESTARTSYS) ret = -EINTR; if (ret > 0 && io_net_retry(sock, flags)) { sr->done_io += ret; req->flags |= REQ_F_PARTIAL_IO; return io_setup_async_msg(req, kmsg); } req_set_fail(req); } else if ((flags & MSG_WAITALL) && (kmsg->msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) { req_set_fail(req); } /* fast path, check for non-NULL to avoid function call */ if (kmsg->free_iov) kfree(kmsg->free_iov); req->flags &= ~REQ_F_NEED_CLEANUP; if (ret >= 0) ret += sr->done_io; else if (sr->done_io) ret = sr->done_io; __io_req_complete(req, issue_flags, ret, io_put_kbuf(req, issue_flags)); return 0; } static int io_recv(struct io_kiocb *req, unsigned int issue_flags) { struct io_buffer *kbuf; struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; void __user *buf = sr->buf; struct socket *sock; struct iovec iov; unsigned flags; int ret, min_ret = 0; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; sock = sock_from_file(req->file); if (unlikely(!sock)) return -ENOTSOCK; if (req->flags & REQ_F_BUFFER_SELECT) { kbuf = io_recv_buffer_select(req, issue_flags); if (IS_ERR(kbuf)) return PTR_ERR(kbuf); buf = u64_to_user_ptr(kbuf->addr); } ret = import_single_range(READ, buf, sr->len, &iov, &msg.msg_iter); if (unlikely(ret)) goto out_free; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; msg.msg_iocb = NULL; msg.msg_flags = 0; flags = req->sr_msg.msg_flags; if (force_nonblock) flags |= MSG_DONTWAIT; if (flags & MSG_WAITALL) min_ret = iov_iter_count(&msg.msg_iter); ret = sock_recvmsg(sock, &msg, flags); if (ret < min_ret) { if (ret == -EAGAIN && force_nonblock) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; if (ret > 0 && io_net_retry(sock, flags)) { sr->len -= ret; sr->buf += ret; sr->done_io += ret; req->flags |= REQ_F_PARTIAL_IO; return -EAGAIN; } req_set_fail(req); } else if ((flags & MSG_WAITALL) && (msg.msg_flags & (MSG_TRUNC | MSG_CTRUNC))) { out_free: req_set_fail(req); } if (ret >= 0) ret += sr->done_io; else if (sr->done_io) ret = sr->done_io; __io_req_complete(req, issue_flags, ret, io_put_kbuf(req, issue_flags)); return 0; } static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_accept *accept = &req->accept; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index) return -EINVAL; accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2)); accept->flags = READ_ONCE(sqe->accept_flags); accept->nofile = rlimit(RLIMIT_NOFILE); accept->file_slot = READ_ONCE(sqe->file_index); if (accept->file_slot && (accept->flags & SOCK_CLOEXEC)) return -EINVAL; if (accept->flags & ~(SOCK_CLOEXEC | SOCK_NONBLOCK)) return -EINVAL; if (SOCK_NONBLOCK != O_NONBLOCK && (accept->flags & SOCK_NONBLOCK)) accept->flags = (accept->flags & ~SOCK_NONBLOCK) | O_NONBLOCK; return 0; } static int io_accept(struct io_kiocb *req, unsigned int issue_flags) { struct io_accept *accept = &req->accept; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0; bool fixed = !!accept->file_slot; struct file *file; int ret, fd; if (!fixed) { fd = __get_unused_fd_flags(accept->flags, accept->nofile); if (unlikely(fd < 0)) return fd; } file = do_accept(req->file, file_flags, accept->addr, accept->addr_len, accept->flags); if (IS_ERR(file)) { if (!fixed) put_unused_fd(fd); ret = PTR_ERR(file); if (ret == -EAGAIN && force_nonblock) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; req_set_fail(req); } else if (!fixed) { fd_install(fd, file); ret = fd; } else { ret = io_install_fixed_file(req, file, issue_flags, accept->file_slot - 1); } __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_connect_prep_async(struct io_kiocb *req) { struct io_async_connect *io = req->async_data; struct io_connect *conn = &req->connect; return move_addr_to_kernel(conn->addr, conn->addr_len, &io->address); } static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_connect *conn = &req->connect; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags || sqe->splice_fd_in) return -EINVAL; conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); conn->addr_len = READ_ONCE(sqe->addr2); return 0; } static int io_connect(struct io_kiocb *req, unsigned int issue_flags) { struct io_async_connect __io, *io; unsigned file_flags; int ret; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; if (req_has_async_data(req)) { io = req->async_data; } else { ret = move_addr_to_kernel(req->connect.addr, req->connect.addr_len, &__io.address); if (ret) goto out; io = &__io; } file_flags = force_nonblock ? O_NONBLOCK : 0; ret = __sys_connect_file(req->file, &io->address, req->connect.addr_len, file_flags); if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) { if (req_has_async_data(req)) return -EAGAIN; if (io_alloc_async_data(req)) { ret = -ENOMEM; goto out; } memcpy(req->async_data, &__io, sizeof(__io)); return -EAGAIN; } if (ret == -ERESTARTSYS) ret = -EINTR; out: if (ret < 0) req_set_fail(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } #else /* !CONFIG_NET */ #define IO_NETOP_FN(op) \ static int io_##op(struct io_kiocb *req, unsigned int issue_flags) \ { \ return -EOPNOTSUPP; \ } #define IO_NETOP_PREP(op) \ IO_NETOP_FN(op) \ static int io_##op##_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) \ { \ return -EOPNOTSUPP; \ } \ #define IO_NETOP_PREP_ASYNC(op) \ IO_NETOP_PREP(op) \ static int io_##op##_prep_async(struct io_kiocb *req) \ { \ return -EOPNOTSUPP; \ } IO_NETOP_PREP_ASYNC(sendmsg); IO_NETOP_PREP_ASYNC(recvmsg); IO_NETOP_PREP_ASYNC(connect); IO_NETOP_PREP(accept); IO_NETOP_FN(send); IO_NETOP_FN(recv); #endif /* CONFIG_NET */ struct io_poll_table { struct poll_table_struct pt; struct io_kiocb *req; int nr_entries; int error; }; #define IO_POLL_CANCEL_FLAG BIT(31) #define IO_POLL_REF_MASK GENMASK(30, 0) /* * If refs part of ->poll_refs (see IO_POLL_REF_MASK) is 0, it's free. We can * bump it and acquire ownership. It's disallowed to modify requests while not * owning it, that prevents from races for enqueueing task_work's and b/w * arming poll and wakeups. */ static inline bool io_poll_get_ownership(struct io_kiocb *req) { return !(atomic_fetch_inc(&req->poll_refs) & IO_POLL_REF_MASK); } static void io_poll_mark_cancelled(struct io_kiocb *req) { atomic_or(IO_POLL_CANCEL_FLAG, &req->poll_refs); } static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req) { /* pure poll stashes this in ->async_data, poll driven retry elsewhere */ if (req->opcode == IORING_OP_POLL_ADD) return req->async_data; return req->apoll->double_poll; } static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req) { if (req->opcode == IORING_OP_POLL_ADD) return &req->poll; return &req->apoll->poll; } static void io_poll_req_insert(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct hlist_head *list; list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)]; hlist_add_head(&req->hash_node, list); } static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events, wait_queue_func_t wake_func) { poll->head = NULL; #define IO_POLL_UNMASK (EPOLLERR|EPOLLHUP|EPOLLNVAL|EPOLLRDHUP) /* mask in events that we always want/need */ poll->events = events | IO_POLL_UNMASK; INIT_LIST_HEAD(&poll->wait.entry); init_waitqueue_func_entry(&poll->wait, wake_func); } static inline void io_poll_remove_entry(struct io_poll_iocb *poll) { struct wait_queue_head *head = smp_load_acquire(&poll->head); if (head) { spin_lock_irq(&head->lock); list_del_init(&poll->wait.entry); poll->head = NULL; spin_unlock_irq(&head->lock); } } static void io_poll_remove_entries(struct io_kiocb *req) { /* * Nothing to do if neither of those flags are set. Avoid dipping * into the poll/apoll/double cachelines if we can. */ if (!(req->flags & (REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL))) return; /* * While we hold the waitqueue lock and the waitqueue is nonempty, * wake_up_pollfree() will wait for us. However, taking the waitqueue * lock in the first place can race with the waitqueue being freed. * * We solve this as eventpoll does: by taking advantage of the fact that * all users of wake_up_pollfree() will RCU-delay the actual free. If * we enter rcu_read_lock() and see that the pointer to the queue is * non-NULL, we can then lock it without the memory being freed out from * under us. * * Keep holding rcu_read_lock() as long as we hold the queue lock, in * case the caller deletes the entry from the queue, leaving it empty. * In that case, only RCU prevents the queue memory from being freed. */ rcu_read_lock(); if (req->flags & REQ_F_SINGLE_POLL) io_poll_remove_entry(io_poll_get_single(req)); if (req->flags & REQ_F_DOUBLE_POLL) io_poll_remove_entry(io_poll_get_double(req)); rcu_read_unlock(); } /* * All poll tw should go through this. Checks for poll events, manages * references, does rewait, etc. * * Returns a negative error on failure. >0 when no action require, which is * either spurious wakeup or multishot CQE is served. 0 when it's done with * the request, then the mask is stored in req->result. */ static int io_poll_check_events(struct io_kiocb *req, bool locked) { struct io_ring_ctx *ctx = req->ctx; struct io_poll_iocb *poll = io_poll_get_single(req); int v; /* req->task == current here, checking PF_EXITING is safe */ if (unlikely(req->task->flags & PF_EXITING)) io_poll_mark_cancelled(req); do { v = atomic_read(&req->poll_refs); /* tw handler should be the owner, and so have some references */ if (WARN_ON_ONCE(!(v & IO_POLL_REF_MASK))) return 0; if (v & IO_POLL_CANCEL_FLAG) return -ECANCELED; if (!req->result) { struct poll_table_struct pt = { ._key = req->cflags }; if (unlikely(!io_assign_file(req, IO_URING_F_UNLOCKED))) req->result = -EBADF; else req->result = vfs_poll(req->file, &pt) & req->cflags; } /* multishot, just fill an CQE and proceed */ if (req->result && !(req->cflags & EPOLLONESHOT)) { __poll_t mask = mangle_poll(req->result & poll->events); bool filled; spin_lock(&ctx->completion_lock); filled = io_fill_cqe_aux(ctx, req->user_data, mask, IORING_CQE_F_MORE); io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); if (unlikely(!filled)) return -ECANCELED; io_cqring_ev_posted(ctx); } else if (req->result) { return 0; } /* * Release all references, retry if someone tried to restart * task_work while we were executing it. */ } while (atomic_sub_return(v & IO_POLL_REF_MASK, &req->poll_refs)); return 1; } static void io_poll_task_func(struct io_kiocb *req, bool *locked) { struct io_ring_ctx *ctx = req->ctx; int ret; ret = io_poll_check_events(req, *locked); if (ret > 0) return; if (!ret) { req->result = mangle_poll(req->result & req->poll.events); } else { req->result = ret; req_set_fail(req); } io_poll_remove_entries(req); spin_lock(&ctx->completion_lock); hash_del(&req->hash_node); __io_req_complete_post(req, req->result, 0); io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_cqring_ev_posted(ctx); } static void io_apoll_task_func(struct io_kiocb *req, bool *locked) { struct io_ring_ctx *ctx = req->ctx; int ret; ret = io_poll_check_events(req, *locked); if (ret > 0) return; io_poll_remove_entries(req); spin_lock(&ctx->completion_lock); hash_del(&req->hash_node); spin_unlock(&ctx->completion_lock); if (!ret) io_req_task_submit(req, locked); else io_req_complete_failed(req, ret); } static void __io_poll_execute(struct io_kiocb *req, int mask, int events) { req->result = mask; /* * This is useful for poll that is armed on behalf of another * request, and where the wakeup path could be on a different * CPU. We want to avoid pulling in req->apoll->events for that * case. */ req->cflags = events; if (req->opcode == IORING_OP_POLL_ADD) req->io_task_work.func = io_poll_task_func; else req->io_task_work.func = io_apoll_task_func; trace_io_uring_task_add(req->ctx, req, req->user_data, req->opcode, mask); io_req_task_work_add(req, false); } static inline void io_poll_execute(struct io_kiocb *req, int res, int events) { if (io_poll_get_ownership(req)) __io_poll_execute(req, res, events); } static void io_poll_cancel_req(struct io_kiocb *req) { io_poll_mark_cancelled(req); /* kick tw, which should complete the request */ io_poll_execute(req, 0, 0); } #define wqe_to_req(wait) ((void *)((unsigned long) (wait)->private & ~1)) #define wqe_is_double(wait) ((unsigned long) (wait)->private & 1) static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_kiocb *req = wqe_to_req(wait); struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb, wait); __poll_t mask = key_to_poll(key); if (unlikely(mask & POLLFREE)) { io_poll_mark_cancelled(req); /* we have to kick tw in case it's not already */ io_poll_execute(req, 0, poll->events); /* * If the waitqueue is being freed early but someone is already * holds ownership over it, we have to tear down the request as * best we can. That means immediately removing the request from * its waitqueue and preventing all further accesses to the * waitqueue via the request. */ list_del_init(&poll->wait.entry); /* * Careful: this *must* be the last step, since as soon * as req->head is NULL'ed out, the request can be * completed and freed, since aio_poll_complete_work() * will no longer need to take the waitqueue lock. */ smp_store_release(&poll->head, NULL); return 1; } /* for instances that support it check for an event match first */ if (mask && !(mask & poll->events)) return 0; if (io_poll_get_ownership(req)) { /* optional, saves extra locking for removal in tw handler */ if (mask && poll->events & EPOLLONESHOT) { list_del_init(&poll->wait.entry); poll->head = NULL; if (wqe_is_double(wait)) req->flags &= ~REQ_F_DOUBLE_POLL; else req->flags &= ~REQ_F_SINGLE_POLL; } __io_poll_execute(req, mask, poll->events); } return 1; } static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt, struct wait_queue_head *head, struct io_poll_iocb **poll_ptr) { struct io_kiocb *req = pt->req; unsigned long wqe_private = (unsigned long) req; /* * The file being polled uses multiple waitqueues for poll handling * (e.g. one for read, one for write). Setup a separate io_poll_iocb * if this happens. */ if (unlikely(pt->nr_entries)) { struct io_poll_iocb *first = poll; /* double add on the same waitqueue head, ignore */ if (first->head == head) return; /* already have a 2nd entry, fail a third attempt */ if (*poll_ptr) { if ((*poll_ptr)->head == head) return; pt->error = -EINVAL; return; } poll = kmalloc(sizeof(*poll), GFP_ATOMIC); if (!poll) { pt->error = -ENOMEM; return; } /* mark as double wq entry */ wqe_private |= 1; req->flags |= REQ_F_DOUBLE_POLL; io_init_poll_iocb(poll, first->events, first->wait.func); *poll_ptr = poll; if (req->opcode == IORING_OP_POLL_ADD) req->flags |= REQ_F_ASYNC_DATA; } req->flags |= REQ_F_SINGLE_POLL; pt->nr_entries++; poll->head = head; poll->wait.private = (void *) wqe_private; if (poll->events & EPOLLEXCLUSIVE) add_wait_queue_exclusive(head, &poll->wait); else add_wait_queue(head, &poll->wait); } static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); __io_queue_proc(&pt->req->poll, pt, head, (struct io_poll_iocb **) &pt->req->async_data); } static int __io_arm_poll_handler(struct io_kiocb *req, struct io_poll_iocb *poll, struct io_poll_table *ipt, __poll_t mask) { struct io_ring_ctx *ctx = req->ctx; int v; INIT_HLIST_NODE(&req->hash_node); io_init_poll_iocb(poll, mask, io_poll_wake); poll->file = req->file; ipt->pt._key = mask; ipt->req = req; ipt->error = 0; ipt->nr_entries = 0; /* * Take the ownership to delay any tw execution up until we're done * with poll arming. see io_poll_get_ownership(). */ atomic_set(&req->poll_refs, 1); mask = vfs_poll(req->file, &ipt->pt) & poll->events; if (mask && (poll->events & EPOLLONESHOT)) { io_poll_remove_entries(req); /* no one else has access to the req, forget about the ref */ return mask; } if (!mask && unlikely(ipt->error || !ipt->nr_entries)) { io_poll_remove_entries(req); if (!ipt->error) ipt->error = -EINVAL; return 0; } spin_lock(&ctx->completion_lock); io_poll_req_insert(req); spin_unlock(&ctx->completion_lock); if (mask) { /* can't multishot if failed, just queue the event we've got */ if (unlikely(ipt->error || !ipt->nr_entries)) poll->events |= EPOLLONESHOT; __io_poll_execute(req, mask, poll->events); return 0; } /* * Release ownership. If someone tried to queue a tw while it was * locked, kick it off for them. */ v = atomic_dec_return(&req->poll_refs); if (unlikely(v & IO_POLL_REF_MASK)) __io_poll_execute(req, 0, poll->events); return 0; } static void io_async_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); struct async_poll *apoll = pt->req->apoll; __io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll); } enum { IO_APOLL_OK, IO_APOLL_ABORTED, IO_APOLL_READY }; static int io_arm_poll_handler(struct io_kiocb *req, unsigned issue_flags) { const struct io_op_def *def = &io_op_defs[req->opcode]; struct io_ring_ctx *ctx = req->ctx; struct async_poll *apoll; struct io_poll_table ipt; __poll_t mask = EPOLLONESHOT | POLLERR | POLLPRI; int ret; if (!def->pollin && !def->pollout) return IO_APOLL_ABORTED; if (!file_can_poll(req->file) || (req->flags & REQ_F_POLLED)) return IO_APOLL_ABORTED; if (def->pollin) { mask |= POLLIN | POLLRDNORM; /* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */ if ((req->opcode == IORING_OP_RECVMSG) && (req->sr_msg.msg_flags & MSG_ERRQUEUE)) mask &= ~POLLIN; } else { mask |= POLLOUT | POLLWRNORM; } if (def->poll_exclusive) mask |= EPOLLEXCLUSIVE; if (!(issue_flags & IO_URING_F_UNLOCKED) && !list_empty(&ctx->apoll_cache)) { apoll = list_first_entry(&ctx->apoll_cache, struct async_poll, poll.wait.entry); list_del_init(&apoll->poll.wait.entry); } else { apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC); if (unlikely(!apoll)) return IO_APOLL_ABORTED; } apoll->double_poll = NULL; req->apoll = apoll; req->flags |= REQ_F_POLLED; ipt.pt._qproc = io_async_queue_proc; io_kbuf_recycle(req, issue_flags); ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask); if (ret || ipt.error) return ret ? IO_APOLL_READY : IO_APOLL_ABORTED; trace_io_uring_poll_arm(ctx, req, req->user_data, req->opcode, mask, apoll->poll.events); return IO_APOLL_OK; } /* * Returns true if we found and killed one or more poll requests */ static __cold bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk, bool cancel_all) { struct hlist_node *tmp; struct io_kiocb *req; bool found = false; int i; spin_lock(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list; list = &ctx->cancel_hash[i]; hlist_for_each_entry_safe(req, tmp, list, hash_node) { if (io_match_task_safe(req, tsk, cancel_all)) { hlist_del_init(&req->hash_node); io_poll_cancel_req(req); found = true; } } } spin_unlock(&ctx->completion_lock); return found; } static struct io_kiocb *io_poll_find(struct io_ring_ctx *ctx, __u64 sqe_addr, bool poll_only) __must_hold(&ctx->completion_lock) { struct hlist_head *list; struct io_kiocb *req; list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)]; hlist_for_each_entry(req, list, hash_node) { if (sqe_addr != req->user_data) continue; if (poll_only && req->opcode != IORING_OP_POLL_ADD) continue; return req; } return NULL; } static bool io_poll_disarm(struct io_kiocb *req) __must_hold(&ctx->completion_lock) { if (!io_poll_get_ownership(req)) return false; io_poll_remove_entries(req); hash_del(&req->hash_node); return true; } static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr, bool poll_only) __must_hold(&ctx->completion_lock) { struct io_kiocb *req = io_poll_find(ctx, sqe_addr, poll_only); if (!req) return -ENOENT; io_poll_cancel_req(req); return 0; } static __poll_t io_poll_parse_events(const struct io_uring_sqe *sqe, unsigned int flags) { u32 events; events = READ_ONCE(sqe->poll32_events); #ifdef __BIG_ENDIAN events = swahw32(events); #endif if (!(flags & IORING_POLL_ADD_MULTI)) events |= EPOLLONESHOT; return demangle_poll(events) | (events & (EPOLLEXCLUSIVE|EPOLLONESHOT)); } static int io_poll_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_poll_update *upd = &req->poll_update; u32 flags; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->splice_fd_in) return -EINVAL; flags = READ_ONCE(sqe->len); if (flags & ~(IORING_POLL_UPDATE_EVENTS | IORING_POLL_UPDATE_USER_DATA | IORING_POLL_ADD_MULTI)) return -EINVAL; /* meaningless without update */ if (flags == IORING_POLL_ADD_MULTI) return -EINVAL; upd->old_user_data = READ_ONCE(sqe->addr); upd->update_events = flags & IORING_POLL_UPDATE_EVENTS; upd->update_user_data = flags & IORING_POLL_UPDATE_USER_DATA; upd->new_user_data = READ_ONCE(sqe->off); if (!upd->update_user_data && upd->new_user_data) return -EINVAL; if (upd->update_events) upd->events = io_poll_parse_events(sqe, flags); else if (sqe->poll32_events) return -EINVAL; return 0; } static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_poll_iocb *poll = &req->poll; u32 flags; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->off || sqe->addr) return -EINVAL; flags = READ_ONCE(sqe->len); if (flags & ~IORING_POLL_ADD_MULTI) return -EINVAL; if ((flags & IORING_POLL_ADD_MULTI) && (req->flags & REQ_F_CQE_SKIP)) return -EINVAL; io_req_set_refcount(req); req->cflags = poll->events = io_poll_parse_events(sqe, flags); return 0; } static int io_poll_add(struct io_kiocb *req, unsigned int issue_flags) { struct io_poll_iocb *poll = &req->poll; struct io_poll_table ipt; int ret; ipt.pt._qproc = io_poll_queue_proc; ret = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events); ret = ret ?: ipt.error; if (ret) __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *preq; int ret2, ret = 0; bool locked; spin_lock(&ctx->completion_lock); preq = io_poll_find(ctx, req->poll_update.old_user_data, true); if (!preq || !io_poll_disarm(preq)) { spin_unlock(&ctx->completion_lock); ret = preq ? -EALREADY : -ENOENT; goto out; } spin_unlock(&ctx->completion_lock); if (req->poll_update.update_events || req->poll_update.update_user_data) { /* only mask one event flags, keep behavior flags */ if (req->poll_update.update_events) { preq->poll.events &= ~0xffff; preq->poll.events |= req->poll_update.events & 0xffff; preq->poll.events |= IO_POLL_UNMASK; } if (req->poll_update.update_user_data) preq->user_data = req->poll_update.new_user_data; ret2 = io_poll_add(preq, issue_flags); /* successfully updated, don't complete poll request */ if (!ret2) goto out; } req_set_fail(preq); preq->result = -ECANCELED; locked = !(issue_flags & IO_URING_F_UNLOCKED); io_req_task_complete(preq, &locked); out: if (ret < 0) req_set_fail(req); /* complete update request, we're done with it */ __io_req_complete(req, issue_flags, ret, 0); return 0; } static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *req = data->req; struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->timeout_lock, flags); list_del_init(&req->timeout.list); atomic_set(&req->ctx->cq_timeouts, atomic_read(&req->ctx->cq_timeouts) + 1); spin_unlock_irqrestore(&ctx->timeout_lock, flags); if (!(data->flags & IORING_TIMEOUT_ETIME_SUCCESS)) req_set_fail(req); req->result = -ETIME; req->io_task_work.func = io_req_task_complete; io_req_task_work_add(req, false); return HRTIMER_NORESTART; } static struct io_kiocb *io_timeout_extract(struct io_ring_ctx *ctx, __u64 user_data) __must_hold(&ctx->timeout_lock) { struct io_timeout_data *io; struct io_kiocb *req; bool found = false; list_for_each_entry(req, &ctx->timeout_list, timeout.list) { found = user_data == req->user_data; if (found) break; } if (!found) return ERR_PTR(-ENOENT); io = req->async_data; if (hrtimer_try_to_cancel(&io->timer) == -1) return ERR_PTR(-EALREADY); list_del_init(&req->timeout.list); return req; } static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data) __must_hold(&ctx->completion_lock) __must_hold(&ctx->timeout_lock) { struct io_kiocb *req = io_timeout_extract(ctx, user_data); if (IS_ERR(req)) return PTR_ERR(req); io_req_task_queue_fail(req, -ECANCELED); return 0; } static clockid_t io_timeout_get_clock(struct io_timeout_data *data) { switch (data->flags & IORING_TIMEOUT_CLOCK_MASK) { case IORING_TIMEOUT_BOOTTIME: return CLOCK_BOOTTIME; case IORING_TIMEOUT_REALTIME: return CLOCK_REALTIME; default: /* can't happen, vetted at prep time */ WARN_ON_ONCE(1); fallthrough; case 0: return CLOCK_MONOTONIC; } } static int io_linked_timeout_update(struct io_ring_ctx *ctx, __u64 user_data, struct timespec64 *ts, enum hrtimer_mode mode) __must_hold(&ctx->timeout_lock) { struct io_timeout_data *io; struct io_kiocb *req; bool found = false; list_for_each_entry(req, &ctx->ltimeout_list, timeout.list) { found = user_data == req->user_data; if (found) break; } if (!found) return -ENOENT; io = req->async_data; if (hrtimer_try_to_cancel(&io->timer) == -1) return -EALREADY; hrtimer_init(&io->timer, io_timeout_get_clock(io), mode); io->timer.function = io_link_timeout_fn; hrtimer_start(&io->timer, timespec64_to_ktime(*ts), mode); return 0; } static int io_timeout_update(struct io_ring_ctx *ctx, __u64 user_data, struct timespec64 *ts, enum hrtimer_mode mode) __must_hold(&ctx->timeout_lock) { struct io_kiocb *req = io_timeout_extract(ctx, user_data); struct io_timeout_data *data; if (IS_ERR(req)) return PTR_ERR(req); req->timeout.off = 0; /* noseq */ data = req->async_data; list_add_tail(&req->timeout.list, &ctx->timeout_list); hrtimer_init(&data->timer, io_timeout_get_clock(data), mode); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(*ts), mode); return 0; } static int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_timeout_rem *tr = &req->timeout_rem; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->len || sqe->splice_fd_in) return -EINVAL; tr->ltimeout = false; tr->addr = READ_ONCE(sqe->addr); tr->flags = READ_ONCE(sqe->timeout_flags); if (tr->flags & IORING_TIMEOUT_UPDATE_MASK) { if (hweight32(tr->flags & IORING_TIMEOUT_CLOCK_MASK) > 1) return -EINVAL; if (tr->flags & IORING_LINK_TIMEOUT_UPDATE) tr->ltimeout = true; if (tr->flags & ~(IORING_TIMEOUT_UPDATE_MASK|IORING_TIMEOUT_ABS)) return -EINVAL; if (get_timespec64(&tr->ts, u64_to_user_ptr(sqe->addr2))) return -EFAULT; if (tr->ts.tv_sec < 0 || tr->ts.tv_nsec < 0) return -EINVAL; } else if (tr->flags) { /* timeout removal doesn't support flags */ return -EINVAL; } return 0; } static inline enum hrtimer_mode io_translate_timeout_mode(unsigned int flags) { return (flags & IORING_TIMEOUT_ABS) ? HRTIMER_MODE_ABS : HRTIMER_MODE_REL; } /* * Remove or update an existing timeout command */ static int io_timeout_remove(struct io_kiocb *req, unsigned int issue_flags) { struct io_timeout_rem *tr = &req->timeout_rem; struct io_ring_ctx *ctx = req->ctx; int ret; if (!(req->timeout_rem.flags & IORING_TIMEOUT_UPDATE)) { spin_lock(&ctx->completion_lock); spin_lock_irq(&ctx->timeout_lock); ret = io_timeout_cancel(ctx, tr->addr); spin_unlock_irq(&ctx->timeout_lock); spin_unlock(&ctx->completion_lock); } else { enum hrtimer_mode mode = io_translate_timeout_mode(tr->flags); spin_lock_irq(&ctx->timeout_lock); if (tr->ltimeout) ret = io_linked_timeout_update(ctx, tr->addr, &tr->ts, mode); else ret = io_timeout_update(ctx, tr->addr, &tr->ts, mode); spin_unlock_irq(&ctx->timeout_lock); } if (ret < 0) req_set_fail(req); io_req_complete_post(req, ret, 0); return 0; } static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool is_timeout_link) { struct io_timeout_data *data; unsigned flags; u32 off = READ_ONCE(sqe->off); if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->len != 1 || sqe->splice_fd_in) return -EINVAL; if (off && is_timeout_link) return -EINVAL; flags = READ_ONCE(sqe->timeout_flags); if (flags & ~(IORING_TIMEOUT_ABS | IORING_TIMEOUT_CLOCK_MASK | IORING_TIMEOUT_ETIME_SUCCESS)) return -EINVAL; /* more than one clock specified is invalid, obviously */ if (hweight32(flags & IORING_TIMEOUT_CLOCK_MASK) > 1) return -EINVAL; INIT_LIST_HEAD(&req->timeout.list); req->timeout.off = off; if (unlikely(off && !req->ctx->off_timeout_used)) req->ctx->off_timeout_used = true; if (WARN_ON_ONCE(req_has_async_data(req))) return -EFAULT; if (io_alloc_async_data(req)) return -ENOMEM; data = req->async_data; data->req = req; data->flags = flags; if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr))) return -EFAULT; if (data->ts.tv_sec < 0 || data->ts.tv_nsec < 0) return -EINVAL; INIT_LIST_HEAD(&req->timeout.list); data->mode = io_translate_timeout_mode(flags); hrtimer_init(&data->timer, io_timeout_get_clock(data), data->mode); if (is_timeout_link) { struct io_submit_link *link = &req->ctx->submit_state.link; if (!link->head) return -EINVAL; if (link->last->opcode == IORING_OP_LINK_TIMEOUT) return -EINVAL; req->timeout.head = link->last; link->last->flags |= REQ_F_ARM_LTIMEOUT; } return 0; } static int io_timeout(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct io_timeout_data *data = req->async_data; struct list_head *entry; u32 tail, off = req->timeout.off; spin_lock_irq(&ctx->timeout_lock); /* * sqe->off holds how many events that need to occur for this * timeout event to be satisfied. If it isn't set, then this is * a pure timeout request, sequence isn't used. */ if (io_is_timeout_noseq(req)) { entry = ctx->timeout_list.prev; goto add; } tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); req->timeout.target_seq = tail + off; /* Update the last seq here in case io_flush_timeouts() hasn't. * This is safe because ->completion_lock is held, and submissions * and completions are never mixed in the same ->completion_lock section. */ ctx->cq_last_tm_flush = tail; /* * Insertion sort, ensuring the first entry in the list is always * the one we need first. */ list_for_each_prev(entry, &ctx->timeout_list) { struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, timeout.list); if (io_is_timeout_noseq(nxt)) continue; /* nxt.seq is behind @tail, otherwise would've been completed */ if (off >= nxt->timeout.target_seq - tail) break; } add: list_add(&req->timeout.list, entry); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); spin_unlock_irq(&ctx->timeout_lock); return 0; } struct io_cancel_data { struct io_ring_ctx *ctx; u64 user_data; }; static bool io_cancel_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct io_cancel_data *cd = data; return req->ctx == cd->ctx && req->user_data == cd->user_data; } static int io_async_cancel_one(struct io_uring_task *tctx, u64 user_data, struct io_ring_ctx *ctx) { struct io_cancel_data data = { .ctx = ctx, .user_data = user_data, }; enum io_wq_cancel cancel_ret; int ret = 0; if (!tctx || !tctx->io_wq) return -ENOENT; cancel_ret = io_wq_cancel_cb(tctx->io_wq, io_cancel_cb, &data, false); switch (cancel_ret) { case IO_WQ_CANCEL_OK: ret = 0; break; case IO_WQ_CANCEL_RUNNING: ret = -EALREADY; break; case IO_WQ_CANCEL_NOTFOUND: ret = -ENOENT; break; } return ret; } static int io_try_cancel_userdata(struct io_kiocb *req, u64 sqe_addr) { struct io_ring_ctx *ctx = req->ctx; int ret; WARN_ON_ONCE(!io_wq_current_is_worker() && req->task != current); ret = io_async_cancel_one(req->task->io_uring, sqe_addr, ctx); /* * Fall-through even for -EALREADY, as we may have poll armed * that need unarming. */ if (!ret) return 0; spin_lock(&ctx->completion_lock); ret = io_poll_cancel(ctx, sqe_addr, false); if (ret != -ENOENT) goto out; spin_lock_irq(&ctx->timeout_lock); ret = io_timeout_cancel(ctx, sqe_addr); spin_unlock_irq(&ctx->timeout_lock); out: spin_unlock(&ctx->completion_lock); return ret; } static int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags || sqe->splice_fd_in) return -EINVAL; req->cancel.addr = READ_ONCE(sqe->addr); return 0; } static int io_async_cancel(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; u64 sqe_addr = req->cancel.addr; bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; struct io_tctx_node *node; int ret; ret = io_try_cancel_userdata(req, sqe_addr); if (ret != -ENOENT) goto done; /* slow path, try all io-wq's */ io_ring_submit_lock(ctx, needs_lock); ret = -ENOENT; list_for_each_entry(node, &ctx->tctx_list, ctx_node) { struct io_uring_task *tctx = node->task->io_uring; ret = io_async_cancel_one(tctx, req->cancel.addr, ctx); if (ret != -ENOENT) break; } io_ring_submit_unlock(ctx, needs_lock); done: if (ret < 0) req_set_fail(req); io_req_complete_post(req, ret, 0); return 0; } static int io_rsrc_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) return -EINVAL; if (sqe->ioprio || sqe->rw_flags || sqe->splice_fd_in) return -EINVAL; req->rsrc_update.offset = READ_ONCE(sqe->off); req->rsrc_update.nr_args = READ_ONCE(sqe->len); if (!req->rsrc_update.nr_args) return -EINVAL; req->rsrc_update.arg = READ_ONCE(sqe->addr); return 0; } static int io_files_update(struct io_kiocb *req, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; struct io_uring_rsrc_update2 up; int ret; up.offset = req->rsrc_update.offset; up.data = req->rsrc_update.arg; up.nr = 0; up.tags = 0; up.resv = 0; io_ring_submit_lock(ctx, needs_lock); ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, req->rsrc_update.nr_args); io_ring_submit_unlock(ctx, needs_lock); if (ret < 0) req_set_fail(req); __io_req_complete(req, issue_flags, ret, 0); return 0; } static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { switch (req->opcode) { case IORING_OP_NOP: return 0; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: return io_prep_rw(req, sqe); case IORING_OP_POLL_ADD: return io_poll_add_prep(req, sqe); case IORING_OP_POLL_REMOVE: return io_poll_update_prep(req, sqe); case IORING_OP_FSYNC: return io_fsync_prep(req, sqe); case IORING_OP_SYNC_FILE_RANGE: return io_sfr_prep(req, sqe); case IORING_OP_SENDMSG: case IORING_OP_SEND: return io_sendmsg_prep(req, sqe); case IORING_OP_RECVMSG: case IORING_OP_RECV: return io_recvmsg_prep(req, sqe); case IORING_OP_CONNECT: return io_connect_prep(req, sqe); case IORING_OP_TIMEOUT: return io_timeout_prep(req, sqe, false); case IORING_OP_TIMEOUT_REMOVE: return io_timeout_remove_prep(req, sqe); case IORING_OP_ASYNC_CANCEL: return io_async_cancel_prep(req, sqe); case IORING_OP_LINK_TIMEOUT: return io_timeout_prep(req, sqe, true); case IORING_OP_ACCEPT: return io_accept_prep(req, sqe); case IORING_OP_FALLOCATE: return io_fallocate_prep(req, sqe); case IORING_OP_OPENAT: return io_openat_prep(req, sqe); case IORING_OP_CLOSE: return io_close_prep(req, sqe); case IORING_OP_FILES_UPDATE: return io_rsrc_update_prep(req, sqe); case IORING_OP_STATX: return io_statx_prep(req, sqe); case IORING_OP_FADVISE: return io_fadvise_prep(req, sqe); case IORING_OP_MADVISE: return io_madvise_prep(req, sqe); case IORING_OP_OPENAT2: return io_openat2_prep(req, sqe); case IORING_OP_EPOLL_CTL: return io_epoll_ctl_prep(req, sqe); case IORING_OP_SPLICE: return io_splice_prep(req, sqe); case IORING_OP_PROVIDE_BUFFERS: return io_provide_buffers_prep(req, sqe); case IORING_OP_REMOVE_BUFFERS: return io_remove_buffers_prep(req, sqe); case IORING_OP_TEE: return io_tee_prep(req, sqe); case IORING_OP_SHUTDOWN: return io_shutdown_prep(req, sqe); case IORING_OP_RENAMEAT: return io_renameat_prep(req, sqe); case IORING_OP_UNLINKAT: return io_unlinkat_prep(req, sqe); case IORING_OP_MKDIRAT: return io_mkdirat_prep(req, sqe); case IORING_OP_SYMLINKAT: return io_symlinkat_prep(req, sqe); case IORING_OP_LINKAT: return io_linkat_prep(req, sqe); case IORING_OP_MSG_RING: return io_msg_ring_prep(req, sqe); } printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n", req->opcode); return -EINVAL; } static int io_req_prep_async(struct io_kiocb *req) { if (!io_op_defs[req->opcode].needs_async_setup) return 0; if (WARN_ON_ONCE(req_has_async_data(req))) return -EFAULT; if (io_alloc_async_data(req)) return -EAGAIN; switch (req->opcode) { case IORING_OP_READV: return io_rw_prep_async(req, READ); case IORING_OP_WRITEV: return io_rw_prep_async(req, WRITE); case IORING_OP_SENDMSG: return io_sendmsg_prep_async(req); case IORING_OP_RECVMSG: return io_recvmsg_prep_async(req); case IORING_OP_CONNECT: return io_connect_prep_async(req); } printk_once(KERN_WARNING "io_uring: prep_async() bad opcode %d\n", req->opcode); return -EFAULT; } static u32 io_get_sequence(struct io_kiocb *req) { u32 seq = req->ctx->cached_sq_head; /* need original cached_sq_head, but it was increased for each req */ io_for_each_link(req, req) seq--; return seq; } static __cold void io_drain_req(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_defer_entry *de; int ret; u32 seq = io_get_sequence(req); /* Still need defer if there is pending req in defer list. */ spin_lock(&ctx->completion_lock); if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) { spin_unlock(&ctx->completion_lock); queue: ctx->drain_active = false; io_req_task_queue(req); return; } spin_unlock(&ctx->completion_lock); ret = io_req_prep_async(req); if (ret) { fail: io_req_complete_failed(req, ret); return; } io_prep_async_link(req); de = kmalloc(sizeof(*de), GFP_KERNEL); if (!de) { ret = -ENOMEM; goto fail; } spin_lock(&ctx->completion_lock); if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) { spin_unlock(&ctx->completion_lock); kfree(de); goto queue; } trace_io_uring_defer(ctx, req, req->user_data, req->opcode); de->req = req; de->seq = seq; list_add_tail(&de->list, &ctx->defer_list); spin_unlock(&ctx->completion_lock); } static void io_clean_op(struct io_kiocb *req) { if (req->flags & REQ_F_BUFFER_SELECTED) { spin_lock(&req->ctx->completion_lock); io_put_kbuf_comp(req); spin_unlock(&req->ctx->completion_lock); } if (req->flags & REQ_F_NEED_CLEANUP) { switch (req->opcode) { case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: { struct io_async_rw *io = req->async_data; kfree(io->free_iovec); break; } case IORING_OP_RECVMSG: case IORING_OP_SENDMSG: { struct io_async_msghdr *io = req->async_data; kfree(io->free_iov); break; } case IORING_OP_OPENAT: case IORING_OP_OPENAT2: if (req->open.filename) putname(req->open.filename); break; case IORING_OP_RENAMEAT: putname(req->rename.oldpath); putname(req->rename.newpath); break; case IORING_OP_UNLINKAT: putname(req->unlink.filename); break; case IORING_OP_MKDIRAT: putname(req->mkdir.filename); break; case IORING_OP_SYMLINKAT: putname(req->symlink.oldpath); putname(req->symlink.newpath); break; case IORING_OP_LINKAT: putname(req->hardlink.oldpath); putname(req->hardlink.newpath); break; case IORING_OP_STATX: if (req->statx.filename) putname(req->statx.filename); break; } } if ((req->flags & REQ_F_POLLED) && req->apoll) { kfree(req->apoll->double_poll); kfree(req->apoll); req->apoll = NULL; } if (req->flags & REQ_F_CREDS) put_cred(req->creds); if (req->flags & REQ_F_ASYNC_DATA) { kfree(req->async_data); req->async_data = NULL; } req->flags &= ~IO_REQ_CLEAN_FLAGS; } static bool io_assign_file(struct io_kiocb *req, unsigned int issue_flags) { if (req->file || !io_op_defs[req->opcode].needs_file) return true; if (req->flags & REQ_F_FIXED_FILE) req->file = io_file_get_fixed(req, req->work.fd, issue_flags); else req->file = io_file_get_normal(req, req->work.fd); if (req->file) return true; req_set_fail(req); req->result = -EBADF; return false; } static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags) { const struct cred *creds = NULL; int ret; if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred())) creds = override_creds(req->creds); if (!io_op_defs[req->opcode].audit_skip) audit_uring_entry(req->opcode); if (unlikely(!io_assign_file(req, issue_flags))) return -EBADF; switch (req->opcode) { case IORING_OP_NOP: ret = io_nop(req, issue_flags); break; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: ret = io_read(req, issue_flags); break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: ret = io_write(req, issue_flags); break; case IORING_OP_FSYNC: ret = io_fsync(req, issue_flags); break; case IORING_OP_POLL_ADD: ret = io_poll_add(req, issue_flags); break; case IORING_OP_POLL_REMOVE: ret = io_poll_update(req, issue_flags); break; case IORING_OP_SYNC_FILE_RANGE: ret = io_sync_file_range(req, issue_flags); break; case IORING_OP_SENDMSG: ret = io_sendmsg(req, issue_flags); break; case IORING_OP_SEND: ret = io_send(req, issue_flags); break; case IORING_OP_RECVMSG: ret = io_recvmsg(req, issue_flags); break; case IORING_OP_RECV: ret = io_recv(req, issue_flags); break; case IORING_OP_TIMEOUT: ret = io_timeout(req, issue_flags); break; case IORING_OP_TIMEOUT_REMOVE: ret = io_timeout_remove(req, issue_flags); break; case IORING_OP_ACCEPT: ret = io_accept(req, issue_flags); break; case IORING_OP_CONNECT: ret = io_connect(req, issue_flags); break; case IORING_OP_ASYNC_CANCEL: ret = io_async_cancel(req, issue_flags); break; case IORING_OP_FALLOCATE: ret = io_fallocate(req, issue_flags); break; case IORING_OP_OPENAT: ret = io_openat(req, issue_flags); break; case IORING_OP_CLOSE: ret = io_close(req, issue_flags); break; case IORING_OP_FILES_UPDATE: ret = io_files_update(req, issue_flags); break; case IORING_OP_STATX: ret = io_statx(req, issue_flags); break; case IORING_OP_FADVISE: ret = io_fadvise(req, issue_flags); break; case IORING_OP_MADVISE: ret = io_madvise(req, issue_flags); break; case IORING_OP_OPENAT2: ret = io_openat2(req, issue_flags); break; case IORING_OP_EPOLL_CTL: ret = io_epoll_ctl(req, issue_flags); break; case IORING_OP_SPLICE: ret = io_splice(req, issue_flags); break; case IORING_OP_PROVIDE_BUFFERS: ret = io_provide_buffers(req, issue_flags); break; case IORING_OP_REMOVE_BUFFERS: ret = io_remove_buffers(req, issue_flags); break; case IORING_OP_TEE: ret = io_tee(req, issue_flags); break; case IORING_OP_SHUTDOWN: ret = io_shutdown(req, issue_flags); break; case IORING_OP_RENAMEAT: ret = io_renameat(req, issue_flags); break; case IORING_OP_UNLINKAT: ret = io_unlinkat(req, issue_flags); break; case IORING_OP_MKDIRAT: ret = io_mkdirat(req, issue_flags); break; case IORING_OP_SYMLINKAT: ret = io_symlinkat(req, issue_flags); break; case IORING_OP_LINKAT: ret = io_linkat(req, issue_flags); break; case IORING_OP_MSG_RING: ret = io_msg_ring(req, issue_flags); break; default: ret = -EINVAL; break; } if (!io_op_defs[req->opcode].audit_skip) audit_uring_exit(!ret, ret); if (creds) revert_creds(creds); if (ret) return ret; /* If the op doesn't have a file, we're not polling for it */ if ((req->ctx->flags & IORING_SETUP_IOPOLL) && req->file) io_iopoll_req_issued(req, issue_flags); return 0; } static struct io_wq_work *io_wq_free_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); req = io_put_req_find_next(req); return req ? &req->work : NULL; } static void io_wq_submit_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); const struct io_op_def *def = &io_op_defs[req->opcode]; unsigned int issue_flags = IO_URING_F_UNLOCKED; bool needs_poll = false; struct io_kiocb *timeout; int ret = 0, err = -ECANCELED; /* one will be dropped by ->io_free_work() after returning to io-wq */ if (!(req->flags & REQ_F_REFCOUNT)) __io_req_set_refcount(req, 2); else req_ref_get(req); timeout = io_prep_linked_timeout(req); if (timeout) io_queue_linked_timeout(timeout); if (!io_assign_file(req, issue_flags)) { err = -EBADF; work->flags |= IO_WQ_WORK_CANCEL; } /* either cancelled or io-wq is dying, so don't touch tctx->iowq */ if (work->flags & IO_WQ_WORK_CANCEL) { io_req_task_queue_fail(req, err); return; } if (req->flags & REQ_F_FORCE_ASYNC) { bool opcode_poll = def->pollin || def->pollout; if (opcode_poll && file_can_poll(req->file)) { needs_poll = true; issue_flags |= IO_URING_F_NONBLOCK; } } do { ret = io_issue_sqe(req, issue_flags); if (ret != -EAGAIN) break; /* * We can get EAGAIN for iopolled IO even though we're * forcing a sync submission from here, since we can't * wait for request slots on the block side. */ if (!needs_poll) { cond_resched(); continue; } if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK) return; /* aborted or ready, in either case retry blocking */ needs_poll = false; issue_flags &= ~IO_URING_F_NONBLOCK; } while (1); /* avoid locking problems by failing it from a clean context */ if (ret) io_req_task_queue_fail(req, ret); } static inline struct io_fixed_file *io_fixed_file_slot(struct io_file_table *table, unsigned i) { return &table->files[i]; } static inline struct file *io_file_from_index(struct io_ring_ctx *ctx, int index) { struct io_fixed_file *slot = io_fixed_file_slot(&ctx->file_table, index); return (struct file *) (slot->file_ptr & FFS_MASK); } static void io_fixed_file_set(struct io_fixed_file *file_slot, struct file *file) { unsigned long file_ptr = (unsigned long) file; file_ptr |= io_file_get_flags(file); file_slot->file_ptr = file_ptr; } static inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd, unsigned int issue_flags) { struct io_ring_ctx *ctx = req->ctx; struct file *file = NULL; unsigned long file_ptr; if (issue_flags & IO_URING_F_UNLOCKED) mutex_lock(&ctx->uring_lock); if (unlikely((unsigned int)fd >= ctx->nr_user_files)) goto out; fd = array_index_nospec(fd, ctx->nr_user_files); file_ptr = io_fixed_file_slot(&ctx->file_table, fd)->file_ptr; file = (struct file *) (file_ptr & FFS_MASK); file_ptr &= ~FFS_MASK; /* mask in overlapping REQ_F and FFS bits */ req->flags |= (file_ptr << REQ_F_SUPPORT_NOWAIT_BIT); io_req_set_rsrc_node(req, ctx, 0); out: if (issue_flags & IO_URING_F_UNLOCKED) mutex_unlock(&ctx->uring_lock); return file; } /* * Drop the file for requeue operations. Only used of req->file is the * io_uring descriptor itself. */ static void io_drop_inflight_file(struct io_kiocb *req) { if (unlikely(req->flags & REQ_F_INFLIGHT)) { fput(req->file); req->file = NULL; req->flags &= ~REQ_F_INFLIGHT; } } static struct file *io_file_get_normal(struct io_kiocb *req, int fd) { struct file *file = fget(fd); trace_io_uring_file_get(req->ctx, req, req->user_data, fd); /* we don't allow fixed io_uring files */ if (file && file->f_op == &io_uring_fops) req->flags |= REQ_F_INFLIGHT; return file; } static void io_req_task_link_timeout(struct io_kiocb *req, bool *locked) { struct io_kiocb *prev = req->timeout.prev; int ret = -ENOENT; if (prev) { if (!(req->task->flags & PF_EXITING)) ret = io_try_cancel_userdata(req, prev->user_data); io_req_complete_post(req, ret ?: -ETIME, 0); io_put_req(prev); } else { io_req_complete_post(req, -ETIME, 0); } } static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *prev, *req = data->req; struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->timeout_lock, flags); prev = req->timeout.head; req->timeout.head = NULL; /* * We don't expect the list to be empty, that will only happen if we * race with the completion of the linked work. */ if (prev) { io_remove_next_linked(prev); if (!req_ref_inc_not_zero(prev)) prev = NULL; } list_del(&req->timeout.list); req->timeout.prev = prev; spin_unlock_irqrestore(&ctx->timeout_lock, flags); req->io_task_work.func = io_req_task_link_timeout; io_req_task_work_add(req, false); return HRTIMER_NORESTART; } static void io_queue_linked_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; spin_lock_irq(&ctx->timeout_lock); /* * If the back reference is NULL, then our linked request finished * before we got a chance to setup the timer */ if (req->timeout.head) { struct io_timeout_data *data = req->async_data; data->timer.function = io_link_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); list_add_tail(&req->timeout.list, &ctx->ltimeout_list); } spin_unlock_irq(&ctx->timeout_lock); /* drop submission reference */ io_put_req(req); } static void io_queue_sqe_arm_apoll(struct io_kiocb *req) __must_hold(&req->ctx->uring_lock) { struct io_kiocb *linked_timeout = io_prep_linked_timeout(req); switch (io_arm_poll_handler(req, 0)) { case IO_APOLL_READY: io_req_task_queue(req); break; case IO_APOLL_ABORTED: /* * Queued up for async execution, worker will release * submit reference when the iocb is actually submitted. */ io_queue_async_work(req, NULL); break; case IO_APOLL_OK: break; } if (linked_timeout) io_queue_linked_timeout(linked_timeout); } static inline void __io_queue_sqe(struct io_kiocb *req) __must_hold(&req->ctx->uring_lock) { struct io_kiocb *linked_timeout; int ret; ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER); if (req->flags & REQ_F_COMPLETE_INLINE) { io_req_add_compl_list(req); return; } /* * We async punt it if the file wasn't marked NOWAIT, or if the file * doesn't support non-blocking read/write attempts */ if (likely(!ret)) { linked_timeout = io_prep_linked_timeout(req); if (linked_timeout) io_queue_linked_timeout(linked_timeout); } else if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) { io_queue_sqe_arm_apoll(req); } else { io_req_complete_failed(req, ret); } } static void io_queue_sqe_fallback(struct io_kiocb *req) __must_hold(&req->ctx->uring_lock) { if (req->flags & REQ_F_FAIL) { io_req_complete_fail_submit(req); } else if (unlikely(req->ctx->drain_active)) { io_drain_req(req); } else { int ret = io_req_prep_async(req); if (unlikely(ret)) io_req_complete_failed(req, ret); else io_queue_async_work(req, NULL); } } static inline void io_queue_sqe(struct io_kiocb *req) __must_hold(&req->ctx->uring_lock) { if (likely(!(req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL)))) __io_queue_sqe(req); else io_queue_sqe_fallback(req); } /* * Check SQE restrictions (opcode and flags). * * Returns 'true' if SQE is allowed, 'false' otherwise. */ static inline bool io_check_restriction(struct io_ring_ctx *ctx, struct io_kiocb *req, unsigned int sqe_flags) { if (!test_bit(req->opcode, ctx->restrictions.sqe_op)) return false; if ((sqe_flags & ctx->restrictions.sqe_flags_required) != ctx->restrictions.sqe_flags_required) return false; if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed | ctx->restrictions.sqe_flags_required)) return false; return true; } static void io_init_req_drain(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *head = ctx->submit_state.link.head; ctx->drain_active = true; if (head) { /* * If we need to drain a request in the middle of a link, drain * the head request and the next request/link after the current * link. Considering sequential execution of links, * REQ_F_IO_DRAIN will be maintained for every request of our * link. */ head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC; ctx->drain_next = true; } } static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_uring_sqe *sqe) __must_hold(&ctx->uring_lock) { unsigned int sqe_flags; int personality; u8 opcode; /* req is partially pre-initialised, see io_preinit_req() */ req->opcode = opcode = READ_ONCE(sqe->opcode); /* same numerical values with corresponding REQ_F_*, safe to copy */ req->flags = sqe_flags = READ_ONCE(sqe->flags); req->user_data = READ_ONCE(sqe->user_data); req->file = NULL; req->fixed_rsrc_refs = NULL; req->task = current; if (unlikely(opcode >= IORING_OP_LAST)) { req->opcode = 0; return -EINVAL; } if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) { /* enforce forwards compatibility on users */ if (sqe_flags & ~SQE_VALID_FLAGS) return -EINVAL; if ((sqe_flags & IOSQE_BUFFER_SELECT) && !io_op_defs[opcode].buffer_select) return -EOPNOTSUPP; if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS) ctx->drain_disabled = true; if (sqe_flags & IOSQE_IO_DRAIN) { if (ctx->drain_disabled) return -EOPNOTSUPP; io_init_req_drain(req); } } if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) { if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags)) return -EACCES; /* knock it to the slow queue path, will be drained there */ if (ctx->drain_active) req->flags |= REQ_F_FORCE_ASYNC; /* if there is no link, we're at "next" request and need to drain */ if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) { ctx->drain_next = false; ctx->drain_active = true; req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC; } } if (io_op_defs[opcode].needs_file) { struct io_submit_state *state = &ctx->submit_state; req->work.fd = READ_ONCE(sqe->fd); /* * Plug now if we have more than 2 IO left after this, and the * target is potentially a read/write to block based storage. */ if (state->need_plug && io_op_defs[opcode].plug) { state->plug_started = true; state->need_plug = false; blk_start_plug_nr_ios(&state->plug, state->submit_nr); } } personality = READ_ONCE(sqe->personality); if (personality) { int ret; req->creds = xa_load(&ctx->personalities, personality); if (!req->creds) return -EINVAL; get_cred(req->creds); ret = security_uring_override_creds(req->creds); if (ret) { put_cred(req->creds); return ret; } req->flags |= REQ_F_CREDS; } return io_req_prep(req, sqe); } static int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_uring_sqe *sqe) __must_hold(&ctx->uring_lock) { struct io_submit_link *link = &ctx->submit_state.link; int ret; ret = io_init_req(ctx, req, sqe); if (unlikely(ret)) { trace_io_uring_req_failed(sqe, ctx, req, ret); /* fail even hard links since we don't submit */ if (link->head) { /* * we can judge a link req is failed or cancelled by if * REQ_F_FAIL is set, but the head is an exception since * it may be set REQ_F_FAIL because of other req's failure * so let's leverage req->result to distinguish if a head * is set REQ_F_FAIL because of its failure or other req's * failure so that we can set the correct ret code for it. * init result here to avoid affecting the normal path. */ if (!(link->head->flags & REQ_F_FAIL)) req_fail_link_node(link->head, -ECANCELED); } else if (!(req->flags & (REQ_F_LINK | REQ_F_HARDLINK))) { /* * the current req is a normal req, we should return * error and thus break the submittion loop. */ io_req_complete_failed(req, ret); return ret; } req_fail_link_node(req, ret); } /* don't need @sqe from now on */ trace_io_uring_submit_sqe(ctx, req, req->user_data, req->opcode, req->flags, true, ctx->flags & IORING_SETUP_SQPOLL); /* * If we already have a head request, queue this one for async * submittal once the head completes. If we don't have a head but * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be * submitted sync once the chain is complete. If none of those * conditions are true (normal request), then just queue it. */ if (link->head) { struct io_kiocb *head = link->head; if (!(req->flags & REQ_F_FAIL)) { ret = io_req_prep_async(req); if (unlikely(ret)) { req_fail_link_node(req, ret); if (!(head->flags & REQ_F_FAIL)) req_fail_link_node(head, -ECANCELED); } } trace_io_uring_link(ctx, req, head); link->last->link = req; link->last = req; if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) return 0; /* last request of a link, enqueue the link */ link->head = NULL; req = head; } else if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) { link->head = req; link->last = req; return 0; } io_queue_sqe(req); return 0; } /* * Batched submission is done, ensure local IO is flushed out. */ static void io_submit_state_end(struct io_ring_ctx *ctx) { struct io_submit_state *state = &ctx->submit_state; if (state->link.head) io_queue_sqe(state->link.head); /* flush only after queuing links as they can generate completions */ io_submit_flush_completions(ctx); if (state->plug_started) blk_finish_plug(&state->plug); } /* * Start submission side cache. */ static void io_submit_state_start(struct io_submit_state *state, unsigned int max_ios) { state->plug_started = false; state->need_plug = max_ios > 2; state->submit_nr = max_ios; /* set only head, no need to init link_last in advance */ state->link.head = NULL; } static void io_commit_sqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* * Ensure any loads from the SQEs are done at this point, * since once we write the new head, the application could * write new data to them. */ smp_store_release(&rings->sq.head, ctx->cached_sq_head); } /* * Fetch an sqe, if one is available. Note this returns a pointer to memory * that is mapped by userspace. This means that care needs to be taken to * ensure that reads are stable, as we cannot rely on userspace always * being a good citizen. If members of the sqe are validated and then later * used, it's important that those reads are done through READ_ONCE() to * prevent a re-load down the line. */ static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx) { unsigned head, mask = ctx->sq_entries - 1; unsigned sq_idx = ctx->cached_sq_head++ & mask; /* * The cached sq head (or cq tail) serves two purposes: * * 1) allows us to batch the cost of updating the user visible * head updates. * 2) allows the kernel side to track the head on its own, even * though the application is the one updating it. */ head = READ_ONCE(ctx->sq_array[sq_idx]); if (likely(head < ctx->sq_entries)) return &ctx->sq_sqes[head]; /* drop invalid entries */ ctx->cq_extra--; WRITE_ONCE(ctx->rings->sq_dropped, READ_ONCE(ctx->rings->sq_dropped) + 1); return NULL; } static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr) __must_hold(&ctx->uring_lock) { unsigned int entries = io_sqring_entries(ctx); int submitted = 0; if (unlikely(!entries)) return 0; /* make sure SQ entry isn't read before tail */ nr = min3(nr, ctx->sq_entries, entries); io_get_task_refs(nr); io_submit_state_start(&ctx->submit_state, nr); do { const struct io_uring_sqe *sqe; struct io_kiocb *req; if (unlikely(!io_alloc_req_refill(ctx))) { if (!submitted) submitted = -EAGAIN; break; } req = io_alloc_req(ctx); sqe = io_get_sqe(ctx); if (unlikely(!sqe)) { wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list); break; } /* will complete beyond this point, count as submitted */ submitted++; if (io_submit_sqe(ctx, req, sqe)) { /* * Continue submitting even for sqe failure if the * ring was setup with IORING_SETUP_SUBMIT_ALL */ if (!(ctx->flags & IORING_SETUP_SUBMIT_ALL)) break; } } while (submitted < nr); if (unlikely(submitted != nr)) { int ref_used = (submitted == -EAGAIN) ? 0 : submitted; int unused = nr - ref_used; current->io_uring->cached_refs += unused; } io_submit_state_end(ctx); /* Commit SQ ring head once we've consumed and submitted all SQEs */ io_commit_sqring(ctx); return submitted; } static inline bool io_sqd_events_pending(struct io_sq_data *sqd) { return READ_ONCE(sqd->state); } static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx) { /* Tell userspace we may need a wakeup call */ spin_lock(&ctx->completion_lock); WRITE_ONCE(ctx->rings->sq_flags, ctx->rings->sq_flags | IORING_SQ_NEED_WAKEUP); spin_unlock(&ctx->completion_lock); } static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx) { spin_lock(&ctx->completion_lock); WRITE_ONCE(ctx->rings->sq_flags, ctx->rings->sq_flags & ~IORING_SQ_NEED_WAKEUP); spin_unlock(&ctx->completion_lock); } static int __io_sq_thread(struct io_ring_ctx *ctx, bool cap_entries) { unsigned int to_submit; int ret = 0; to_submit = io_sqring_entries(ctx); /* if we're handling multiple rings, cap submit size for fairness */ if (cap_entries && to_submit > IORING_SQPOLL_CAP_ENTRIES_VALUE) to_submit = IORING_SQPOLL_CAP_ENTRIES_VALUE; if (!wq_list_empty(&ctx->iopoll_list) || to_submit) { const struct cred *creds = NULL; if (ctx->sq_creds != current_cred()) creds = override_creds(ctx->sq_creds); mutex_lock(&ctx->uring_lock); if (!wq_list_empty(&ctx->iopoll_list)) io_do_iopoll(ctx, true); /* * Don't submit if refs are dying, good for io_uring_register(), * but also it is relied upon by io_ring_exit_work() */ if (to_submit && likely(!percpu_ref_is_dying(&ctx->refs)) && !(ctx->flags & IORING_SETUP_R_DISABLED)) ret = io_submit_sqes(ctx, to_submit); mutex_unlock(&ctx->uring_lock); if (to_submit && wq_has_sleeper(&ctx->sqo_sq_wait)) wake_up(&ctx->sqo_sq_wait); if (creds) revert_creds(creds); } return ret; } static __cold void io_sqd_update_thread_idle(struct io_sq_data *sqd) { struct io_ring_ctx *ctx; unsigned sq_thread_idle = 0; list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) sq_thread_idle = max(sq_thread_idle, ctx->sq_thread_idle); sqd->sq_thread_idle = sq_thread_idle; } static bool io_sqd_handle_event(struct io_sq_data *sqd) { bool did_sig = false; struct ksignal ksig; if (test_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state) || signal_pending(current)) { mutex_unlock(&sqd->lock); if (signal_pending(current)) did_sig = get_signal(&ksig); cond_resched(); mutex_lock(&sqd->lock); } return did_sig || test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state); } static int io_sq_thread(void *data) { struct io_sq_data *sqd = data; struct io_ring_ctx *ctx; unsigned long timeout = 0; char buf[TASK_COMM_LEN]; DEFINE_WAIT(wait); snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid); set_task_comm(current, buf); if (sqd->sq_cpu != -1) set_cpus_allowed_ptr(current, cpumask_of(sqd->sq_cpu)); else set_cpus_allowed_ptr(current, cpu_online_mask); current->flags |= PF_NO_SETAFFINITY; audit_alloc_kernel(current); mutex_lock(&sqd->lock); while (1) { bool cap_entries, sqt_spin = false; if (io_sqd_events_pending(sqd) || signal_pending(current)) { if (io_sqd_handle_event(sqd)) break; timeout = jiffies + sqd->sq_thread_idle; } cap_entries = !list_is_singular(&sqd->ctx_list); list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { int ret = __io_sq_thread(ctx, cap_entries); if (!sqt_spin && (ret > 0 || !wq_list_empty(&ctx->iopoll_list))) sqt_spin = true; } if (io_run_task_work()) sqt_spin = true; if (sqt_spin || !time_after(jiffies, timeout)) { cond_resched(); if (sqt_spin) timeout = jiffies + sqd->sq_thread_idle; continue; } prepare_to_wait(&sqd->wait, &wait, TASK_INTERRUPTIBLE); if (!io_sqd_events_pending(sqd) && !task_work_pending(current)) { bool needs_sched = true; list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) { io_ring_set_wakeup_flag(ctx); if ((ctx->flags & IORING_SETUP_IOPOLL) && !wq_list_empty(&ctx->iopoll_list)) { needs_sched = false; break; } /* * Ensure the store of the wakeup flag is not * reordered with the load of the SQ tail */ smp_mb(); if (io_sqring_entries(ctx)) { needs_sched = false; break; } } if (needs_sched) { mutex_unlock(&sqd->lock); schedule(); mutex_lock(&sqd->lock); } list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) io_ring_clear_wakeup_flag(ctx); } finish_wait(&sqd->wait, &wait); timeout = jiffies + sqd->sq_thread_idle; } io_uring_cancel_generic(true, sqd); sqd->thread = NULL; list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) io_ring_set_wakeup_flag(ctx); io_run_task_work(); mutex_unlock(&sqd->lock); audit_free(current); complete(&sqd->exited); do_exit(0); } struct io_wait_queue { struct wait_queue_entry wq; struct io_ring_ctx *ctx; unsigned cq_tail; unsigned nr_timeouts; }; static inline bool io_should_wake(struct io_wait_queue *iowq) { struct io_ring_ctx *ctx = iowq->ctx; int dist = ctx->cached_cq_tail - (int) iowq->cq_tail; /* * Wake up if we have enough events, or if a timeout occurred since we * started waiting. For timeouts, we always want to return to userspace, * regardless of event count. */ return dist >= 0 || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; } static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode, int wake_flags, void *key) { struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq); /* * Cannot safely flush overflowed CQEs from here, ensure we wake up * the task, and the next invocation will do it. */ if (io_should_wake(iowq) || test_bit(0, &iowq->ctx->check_cq_overflow)) return autoremove_wake_function(curr, mode, wake_flags, key); return -1; } static int io_run_task_work_sig(void) { if (io_run_task_work()) return 1; if (test_thread_flag(TIF_NOTIFY_SIGNAL)) return -ERESTARTSYS; if (task_sigpending(current)) return -EINTR; return 0; } /* when returns >0, the caller should retry */ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx, struct io_wait_queue *iowq, ktime_t timeout) { int ret; /* make sure we run task_work before checking for signals */ ret = io_run_task_work_sig(); if (ret || io_should_wake(iowq)) return ret; /* let the caller flush overflows, retry */ if (test_bit(0, &ctx->check_cq_overflow)) return 1; if (!schedule_hrtimeout(&timeout, HRTIMER_MODE_ABS)) return -ETIME; return 1; } /* * Wait until events become available, if we don't already have some. The * application must reap them itself, as they reside on the shared cq ring. */ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, const sigset_t __user *sig, size_t sigsz, struct __kernel_timespec __user *uts) { struct io_wait_queue iowq; struct io_rings *rings = ctx->rings; ktime_t timeout = KTIME_MAX; int ret; do { io_cqring_overflow_flush(ctx); if (io_cqring_events(ctx) >= min_events) return 0; if (!io_run_task_work()) break; } while (1); if (sig) { #ifdef CONFIG_COMPAT if (in_compat_syscall()) ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig, sigsz); else #endif ret = set_user_sigmask(sig, sigsz); if (ret) return ret; } if (uts) { struct timespec64 ts; if (get_timespec64(&ts, uts)) return -EFAULT; timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns()); } init_waitqueue_func_entry(&iowq.wq, io_wake_function); iowq.wq.private = current; INIT_LIST_HEAD(&iowq.wq.entry); iowq.ctx = ctx; iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events; trace_io_uring_cqring_wait(ctx, min_events); do { /* if we can't even flush overflow, don't wait for more */ if (!io_cqring_overflow_flush(ctx)) { ret = -EBUSY; break; } prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq, TASK_INTERRUPTIBLE); ret = io_cqring_wait_schedule(ctx, &iowq, timeout); finish_wait(&ctx->cq_wait, &iowq.wq); cond_resched(); } while (ret > 0); restore_saved_sigmask_unless(ret == -EINTR); return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0; } static void io_free_page_table(void **table, size_t size) { unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); for (i = 0; i < nr_tables; i++) kfree(table[i]); kfree(table); } static __cold void **io_alloc_page_table(size_t size) { unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); size_t init_size = size; void **table; table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT); if (!table) return NULL; for (i = 0; i < nr_tables; i++) { unsigned int this_size = min_t(size_t, size, PAGE_SIZE); table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT); if (!table[i]) { io_free_page_table(table, init_size); return NULL; } size -= this_size; } return table; } static void io_rsrc_node_destroy(struct io_rsrc_node *ref_node) { percpu_ref_exit(&ref_node->refs); kfree(ref_node); } static __cold void io_rsrc_node_ref_zero(struct percpu_ref *ref) { struct io_rsrc_node *node = container_of(ref, struct io_rsrc_node, refs); struct io_ring_ctx *ctx = node->rsrc_data->ctx; unsigned long flags; bool first_add = false; unsigned long delay = HZ; spin_lock_irqsave(&ctx->rsrc_ref_lock, flags); node->done = true; /* if we are mid-quiesce then do not delay */ if (node->rsrc_data->quiesce) delay = 0; while (!list_empty(&ctx->rsrc_ref_list)) { node = list_first_entry(&ctx->rsrc_ref_list, struct io_rsrc_node, node); /* recycle ref nodes in order */ if (!node->done) break; list_del(&node->node); first_add |= llist_add(&node->llist, &ctx->rsrc_put_llist); } spin_unlock_irqrestore(&ctx->rsrc_ref_lock, flags); if (first_add) mod_delayed_work(system_wq, &ctx->rsrc_put_work, delay); } static struct io_rsrc_node *io_rsrc_node_alloc(void) { struct io_rsrc_node *ref_node; ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); if (!ref_node) return NULL; if (percpu_ref_init(&ref_node->refs, io_rsrc_node_ref_zero, 0, GFP_KERNEL)) { kfree(ref_node); return NULL; } INIT_LIST_HEAD(&ref_node->node); INIT_LIST_HEAD(&ref_node->rsrc_list); ref_node->done = false; return ref_node; } static void io_rsrc_node_switch(struct io_ring_ctx *ctx, struct io_rsrc_data *data_to_kill) __must_hold(&ctx->uring_lock) { WARN_ON_ONCE(!ctx->rsrc_backup_node); WARN_ON_ONCE(data_to_kill && !ctx->rsrc_node); io_rsrc_refs_drop(ctx); if (data_to_kill) { struct io_rsrc_node *rsrc_node = ctx->rsrc_node; rsrc_node->rsrc_data = data_to_kill; spin_lock_irq(&ctx->rsrc_ref_lock); list_add_tail(&rsrc_node->node, &ctx->rsrc_ref_list); spin_unlock_irq(&ctx->rsrc_ref_lock); atomic_inc(&data_to_kill->refs); percpu_ref_kill(&rsrc_node->refs); ctx->rsrc_node = NULL; } if (!ctx->rsrc_node) { ctx->rsrc_node = ctx->rsrc_backup_node; ctx->rsrc_backup_node = NULL; } } static int io_rsrc_node_switch_start(struct io_ring_ctx *ctx) { if (ctx->rsrc_backup_node) return 0; ctx->rsrc_backup_node = io_rsrc_node_alloc(); return ctx->rsrc_backup_node ? 0 : -ENOMEM; } static __cold int io_rsrc_ref_quiesce(struct io_rsrc_data *data, struct io_ring_ctx *ctx) { int ret; /* As we may drop ->uring_lock, other task may have started quiesce */ if (data->quiesce) return -ENXIO; data->quiesce = true; do { ret = io_rsrc_node_switch_start(ctx); if (ret) break; io_rsrc_node_switch(ctx, data); /* kill initial ref, already quiesced if zero */ if (atomic_dec_and_test(&data->refs)) break; mutex_unlock(&ctx->uring_lock); flush_delayed_work(&ctx->rsrc_put_work); ret = wait_for_completion_interruptible(&data->done); if (!ret) { mutex_lock(&ctx->uring_lock); if (atomic_read(&data->refs) > 0) { /* * it has been revived by another thread while * we were unlocked */ mutex_unlock(&ctx->uring_lock); } else { break; } } atomic_inc(&data->refs); /* wait for all works potentially completing data->done */ flush_delayed_work(&ctx->rsrc_put_work); reinit_completion(&data->done); ret = io_run_task_work_sig(); mutex_lock(&ctx->uring_lock); } while (ret >= 0); data->quiesce = false; return ret; } static u64 *io_get_tag_slot(struct io_rsrc_data *data, unsigned int idx) { unsigned int off = idx & IO_RSRC_TAG_TABLE_MASK; unsigned int table_idx = idx >> IO_RSRC_TAG_TABLE_SHIFT; return &data->tags[table_idx][off]; } static void io_rsrc_data_free(struct io_rsrc_data *data) { size_t size = data->nr * sizeof(data->tags[0][0]); if (data->tags) io_free_page_table((void **)data->tags, size); kfree(data); } static __cold int io_rsrc_data_alloc(struct io_ring_ctx *ctx, rsrc_put_fn *do_put, u64 __user *utags, unsigned nr, struct io_rsrc_data **pdata) { struct io_rsrc_data *data; int ret = -ENOMEM; unsigned i; data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0])); if (!data->tags) { kfree(data); return -ENOMEM; } data->nr = nr; data->ctx = ctx; data->do_put = do_put; if (utags) { ret = -EFAULT; for (i = 0; i < nr; i++) { u64 *tag_slot = io_get_tag_slot(data, i); if (copy_from_user(tag_slot, &utags[i], sizeof(*tag_slot))) goto fail; } } atomic_set(&data->refs, 1); init_completion(&data->done); *pdata = data; return 0; fail: io_rsrc_data_free(data); return ret; } static bool io_alloc_file_tables(struct io_file_table *table, unsigned nr_files) { table->files = kvcalloc(nr_files, sizeof(table->files[0]), GFP_KERNEL_ACCOUNT); return !!table->files; } static void io_free_file_tables(struct io_file_table *table) { kvfree(table->files); table->files = NULL; } static void __io_sqe_files_unregister(struct io_ring_ctx *ctx) { #if defined(CONFIG_UNIX) if (ctx->ring_sock) { struct sock *sock = ctx->ring_sock->sk; struct sk_buff *skb; while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) kfree_skb(skb); } #else int i; for (i = 0; i < ctx->nr_user_files; i++) { struct file *file; file = io_file_from_index(ctx, i); if (file) fput(file); } #endif io_free_file_tables(&ctx->file_table); io_rsrc_data_free(ctx->file_data); ctx->file_data = NULL; ctx->nr_user_files = 0; } static int io_sqe_files_unregister(struct io_ring_ctx *ctx) { int ret; if (!ctx->file_data) return -ENXIO; ret = io_rsrc_ref_quiesce(ctx->file_data, ctx); if (!ret) __io_sqe_files_unregister(ctx); return ret; } static void io_sq_thread_unpark(struct io_sq_data *sqd) __releases(&sqd->lock) { WARN_ON_ONCE(sqd->thread == current); /* * Do the dance but not conditional clear_bit() because it'd race with * other threads incrementing park_pending and setting the bit. */ clear_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state); if (atomic_dec_return(&sqd->park_pending)) set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state); mutex_unlock(&sqd->lock); } static void io_sq_thread_park(struct io_sq_data *sqd) __acquires(&sqd->lock) { WARN_ON_ONCE(sqd->thread == current); atomic_inc(&sqd->park_pending); set_bit(IO_SQ_THREAD_SHOULD_PARK, &sqd->state); mutex_lock(&sqd->lock); if (sqd->thread) wake_up_process(sqd->thread); } static void io_sq_thread_stop(struct io_sq_data *sqd) { WARN_ON_ONCE(sqd->thread == current); WARN_ON_ONCE(test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state)); set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state); mutex_lock(&sqd->lock); if (sqd->thread) wake_up_process(sqd->thread); mutex_unlock(&sqd->lock); wait_for_completion(&sqd->exited); } static void io_put_sq_data(struct io_sq_data *sqd) { if (refcount_dec_and_test(&sqd->refs)) { WARN_ON_ONCE(atomic_read(&sqd->park_pending)); io_sq_thread_stop(sqd); kfree(sqd); } } static void io_sq_thread_finish(struct io_ring_ctx *ctx) { struct io_sq_data *sqd = ctx->sq_data; if (sqd) { io_sq_thread_park(sqd); list_del_init(&ctx->sqd_list); io_sqd_update_thread_idle(sqd); io_sq_thread_unpark(sqd); io_put_sq_data(sqd); ctx->sq_data = NULL; } } static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p) { struct io_ring_ctx *ctx_attach; struct io_sq_data *sqd; struct fd f; f = fdget(p->wq_fd); if (!f.file) return ERR_PTR(-ENXIO); if (f.file->f_op != &io_uring_fops) { fdput(f); return ERR_PTR(-EINVAL); } ctx_attach = f.file->private_data; sqd = ctx_attach->sq_data; if (!sqd) { fdput(f); return ERR_PTR(-EINVAL); } if (sqd->task_tgid != current->tgid) { fdput(f); return ERR_PTR(-EPERM); } refcount_inc(&sqd->refs); fdput(f); return sqd; } static struct io_sq_data *io_get_sq_data(struct io_uring_params *p, bool *attached) { struct io_sq_data *sqd; *attached = false; if (p->flags & IORING_SETUP_ATTACH_WQ) { sqd = io_attach_sq_data(p); if (!IS_ERR(sqd)) { *attached = true; return sqd; } /* fall through for EPERM case, setup new sqd/task */ if (PTR_ERR(sqd) != -EPERM) return sqd; } sqd = kzalloc(sizeof(*sqd), GFP_KERNEL); if (!sqd) return ERR_PTR(-ENOMEM); atomic_set(&sqd->park_pending, 0); refcount_set(&sqd->refs, 1); INIT_LIST_HEAD(&sqd->ctx_list); mutex_init(&sqd->lock); init_waitqueue_head(&sqd->wait); init_completion(&sqd->exited); return sqd; } #if defined(CONFIG_UNIX) /* * Ensure the UNIX gc is aware of our file set, so we are certain that * the io_uring can be safely unregistered on process exit, even if we have * loops in the file referencing. */ static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset) { struct sock *sk = ctx->ring_sock->sk; struct scm_fp_list *fpl; struct sk_buff *skb; int i, nr_files; fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); if (!fpl) return -ENOMEM; skb = alloc_skb(0, GFP_KERNEL); if (!skb) { kfree(fpl); return -ENOMEM; } skb->sk = sk; nr_files = 0; fpl->user = get_uid(current_user()); for (i = 0; i < nr; i++) { struct file *file = io_file_from_index(ctx, i + offset); if (!file) continue; fpl->fp[nr_files] = get_file(file); unix_inflight(fpl->user, fpl->fp[nr_files]); nr_files++; } if (nr_files) { fpl->max = SCM_MAX_FD; fpl->count = nr_files; UNIXCB(skb).fp = fpl; skb->destructor = unix_destruct_scm; refcount_add(skb->truesize, &sk->sk_wmem_alloc); skb_queue_head(&sk->sk_receive_queue, skb); for (i = 0; i < nr; i++) { struct file *file = io_file_from_index(ctx, i + offset); if (file) fput(file); } } else { kfree_skb(skb); free_uid(fpl->user); kfree(fpl); } return 0; } /* * If UNIX sockets are enabled, fd passing can cause a reference cycle which * causes regular reference counting to break down. We rely on the UNIX * garbage collection to take care of this problem for us. */ static int io_sqe_files_scm(struct io_ring_ctx *ctx) { unsigned left, total; int ret = 0; total = 0; left = ctx->nr_user_files; while (left) { unsigned this_files = min_t(unsigned, left, SCM_MAX_FD); ret = __io_sqe_files_scm(ctx, this_files, total); if (ret) break; left -= this_files; total += this_files; } if (!ret) return 0; while (total < ctx->nr_user_files) { struct file *file = io_file_from_index(ctx, total); if (file) fput(file); total++; } return ret; } #else static int io_sqe_files_scm(struct io_ring_ctx *ctx) { return 0; } #endif static void io_rsrc_file_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) { struct file *file = prsrc->file; #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head list, *head = &sock->sk_receive_queue; struct sk_buff *skb; int i; __skb_queue_head_init(&list); /* * Find the skb that holds this file in its SCM_RIGHTS. When found, * remove this entry and rearrange the file array. */ skb = skb_dequeue(head); while (skb) { struct scm_fp_list *fp; fp = UNIXCB(skb).fp; for (i = 0; i < fp->count; i++) { int left; if (fp->fp[i] != file) continue; unix_notinflight(fp->user, fp->fp[i]); left = fp->count - 1 - i; if (left) { memmove(&fp->fp[i], &fp->fp[i + 1], left * sizeof(struct file *)); } fp->count--; if (!fp->count) { kfree_skb(skb); skb = NULL; } else { __skb_queue_tail(&list, skb); } fput(file); file = NULL; break; } if (!file) break; __skb_queue_tail(&list, skb); skb = skb_dequeue(head); } if (skb_peek(&list)) { spin_lock_irq(&head->lock); while ((skb = __skb_dequeue(&list)) != NULL) __skb_queue_tail(head, skb); spin_unlock_irq(&head->lock); } #else fput(file); #endif } static void __io_rsrc_put_work(struct io_rsrc_node *ref_node) { struct io_rsrc_data *rsrc_data = ref_node->rsrc_data; struct io_ring_ctx *ctx = rsrc_data->ctx; struct io_rsrc_put *prsrc, *tmp; list_for_each_entry_safe(prsrc, tmp, &ref_node->rsrc_list, list) { list_del(&prsrc->list); if (prsrc->tag) { bool lock_ring = ctx->flags & IORING_SETUP_IOPOLL; io_ring_submit_lock(ctx, lock_ring); spin_lock(&ctx->completion_lock); io_fill_cqe_aux(ctx, prsrc->tag, 0, 0); io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); io_cqring_ev_posted(ctx); io_ring_submit_unlock(ctx, lock_ring); } rsrc_data->do_put(ctx, prsrc); kfree(prsrc); } io_rsrc_node_destroy(ref_node); if (atomic_dec_and_test(&rsrc_data->refs)) complete(&rsrc_data->done); } static void io_rsrc_put_work(struct work_struct *work) { struct io_ring_ctx *ctx; struct llist_node *node; ctx = container_of(work, struct io_ring_ctx, rsrc_put_work.work); node = llist_del_all(&ctx->rsrc_put_llist); while (node) { struct io_rsrc_node *ref_node; struct llist_node *next = node->next; ref_node = llist_entry(node, struct io_rsrc_node, llist); __io_rsrc_put_work(ref_node); node = next; } } static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args, u64 __user *tags) { __s32 __user *fds = (__s32 __user *) arg; struct file *file; int fd, ret; unsigned i; if (ctx->file_data) return -EBUSY; if (!nr_args) return -EINVAL; if (nr_args > IORING_MAX_FIXED_FILES) return -EMFILE; if (nr_args > rlimit(RLIMIT_NOFILE)) return -EMFILE; ret = io_rsrc_node_switch_start(ctx); if (ret) return ret; ret = io_rsrc_data_alloc(ctx, io_rsrc_file_put, tags, nr_args, &ctx->file_data); if (ret) return ret; ret = -ENOMEM; if (!io_alloc_file_tables(&ctx->file_table, nr_args)) goto out_free; for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { if (copy_from_user(&fd, &fds[i], sizeof(fd))) { ret = -EFAULT; goto out_fput; } /* allow sparse sets */ if (fd == -1) { ret = -EINVAL; if (unlikely(*io_get_tag_slot(ctx->file_data, i))) goto out_fput; continue; } file = fget(fd); ret = -EBADF; if (unlikely(!file)) goto out_fput; /* * Don't allow io_uring instances to be registered. If UNIX * isn't enabled, then this causes a reference cycle and this * instance can never get freed. If UNIX is enabled we'll * handle it just fine, but there's still no point in allowing * a ring fd as it doesn't support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); goto out_fput; } io_fixed_file_set(io_fixed_file_slot(&ctx->file_table, i), file); } ret = io_sqe_files_scm(ctx); if (ret) { __io_sqe_files_unregister(ctx); return ret; } io_rsrc_node_switch(ctx, NULL); return ret; out_fput: for (i = 0; i < ctx->nr_user_files; i++) { file = io_file_from_index(ctx, i); if (file) fput(file); } io_free_file_tables(&ctx->file_table); ctx->nr_user_files = 0; out_free: io_rsrc_data_free(ctx->file_data); ctx->file_data = NULL; return ret; } static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, int index) { #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head *head = &sock->sk_receive_queue; struct sk_buff *skb; /* * See if we can merge this file into an existing skb SCM_RIGHTS * file set. If there's no room, fall back to allocating a new skb * and filling it in. */ spin_lock_irq(&head->lock); skb = skb_peek(head); if (skb) { struct scm_fp_list *fpl = UNIXCB(skb).fp; if (fpl->count < SCM_MAX_FD) { __skb_unlink(skb, head); spin_unlock_irq(&head->lock); fpl->fp[fpl->count] = get_file(file); unix_inflight(fpl->user, fpl->fp[fpl->count]); fpl->count++; spin_lock_irq(&head->lock); __skb_queue_head(head, skb); } else { skb = NULL; } } spin_unlock_irq(&head->lock); if (skb) { fput(file); return 0; } return __io_sqe_files_scm(ctx, 1, index); #else return 0; #endif } static int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, struct io_rsrc_node *node, void *rsrc) { u64 *tag_slot = io_get_tag_slot(data, idx); struct io_rsrc_put *prsrc; prsrc = kzalloc(sizeof(*prsrc), GFP_KERNEL); if (!prsrc) return -ENOMEM; prsrc->tag = *tag_slot; *tag_slot = 0; prsrc->rsrc = rsrc; list_add(&prsrc->list, &node->rsrc_list); return 0; } static int io_install_fixed_file(struct io_kiocb *req, struct file *file, unsigned int issue_flags, u32 slot_index) { struct io_ring_ctx *ctx = req->ctx; bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; bool needs_switch = false; struct io_fixed_file *file_slot; int ret = -EBADF; io_ring_submit_lock(ctx, needs_lock); if (file->f_op == &io_uring_fops) goto err; ret = -ENXIO; if (!ctx->file_data) goto err; ret = -EINVAL; if (slot_index >= ctx->nr_user_files) goto err; slot_index = array_index_nospec(slot_index, ctx->nr_user_files); file_slot = io_fixed_file_slot(&ctx->file_table, slot_index); if (file_slot->file_ptr) { struct file *old_file; ret = io_rsrc_node_switch_start(ctx); if (ret) goto err; old_file = (struct file *)(file_slot->file_ptr & FFS_MASK); ret = io_queue_rsrc_removal(ctx->file_data, slot_index, ctx->rsrc_node, old_file); if (ret) goto err; file_slot->file_ptr = 0; needs_switch = true; } *io_get_tag_slot(ctx->file_data, slot_index) = 0; io_fixed_file_set(file_slot, file); ret = io_sqe_file_register(ctx, file, slot_index); if (ret) { file_slot->file_ptr = 0; goto err; } ret = 0; err: if (needs_switch) io_rsrc_node_switch(ctx, ctx->file_data); io_ring_submit_unlock(ctx, needs_lock); if (ret) fput(file); return ret; } static int io_close_fixed(struct io_kiocb *req, unsigned int issue_flags) { unsigned int offset = req->close.file_slot - 1; struct io_ring_ctx *ctx = req->ctx; bool needs_lock = issue_flags & IO_URING_F_UNLOCKED; struct io_fixed_file *file_slot; struct file *file; int ret; io_ring_submit_lock(ctx, needs_lock); ret = -ENXIO; if (unlikely(!ctx->file_data)) goto out; ret = -EINVAL; if (offset >= ctx->nr_user_files) goto out; ret = io_rsrc_node_switch_start(ctx); if (ret) goto out; offset = array_index_nospec(offset, ctx->nr_user_files); file_slot = io_fixed_file_slot(&ctx->file_table, offset); ret = -EBADF; if (!file_slot->file_ptr) goto out; file = (struct file *)(file_slot->file_ptr & FFS_MASK); ret = io_queue_rsrc_removal(ctx->file_data, offset, ctx->rsrc_node, file); if (ret) goto out; file_slot->file_ptr = 0; io_rsrc_node_switch(ctx, ctx->file_data); ret = 0; out: io_ring_submit_unlock(ctx, needs_lock); return ret; } static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_rsrc_update2 *up, unsigned nr_args) { u64 __user *tags = u64_to_user_ptr(up->tags); __s32 __user *fds = u64_to_user_ptr(up->data); struct io_rsrc_data *data = ctx->file_data; struct io_fixed_file *file_slot; struct file *file; int fd, i, err = 0; unsigned int done; bool needs_switch = false; if (!ctx->file_data) return -ENXIO; if (up->offset + nr_args > ctx->nr_user_files) return -EINVAL; for (done = 0; done < nr_args; done++) { u64 tag = 0; if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) || copy_from_user(&fd, &fds[done], sizeof(fd))) { err = -EFAULT; break; } if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) { err = -EINVAL; break; } if (fd == IORING_REGISTER_FILES_SKIP) continue; i = array_index_nospec(up->offset + done, ctx->nr_user_files); file_slot = io_fixed_file_slot(&ctx->file_table, i); if (file_slot->file_ptr) { file = (struct file *)(file_slot->file_ptr & FFS_MASK); err = io_queue_rsrc_removal(data, i, ctx->rsrc_node, file); if (err) break; file_slot->file_ptr = 0; needs_switch = true; } if (fd != -1) { file = fget(fd); if (!file) { err = -EBADF; break; } /* * Don't allow io_uring instances to be registered. If * UNIX isn't enabled, then this causes a reference * cycle and this instance can never get freed. If UNIX * is enabled we'll handle it just fine, but there's * still no point in allowing a ring fd as it doesn't * support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); err = -EBADF; break; } *io_get_tag_slot(data, i) = tag; io_fixed_file_set(file_slot, file); err = io_sqe_file_register(ctx, file, i); if (err) { file_slot->file_ptr = 0; fput(file); break; } } } if (needs_switch) io_rsrc_node_switch(ctx, data); return done ? done : err; } static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx, struct task_struct *task) { struct io_wq_hash *hash; struct io_wq_data data; unsigned int concurrency; mutex_lock(&ctx->uring_lock); hash = ctx->hash_map; if (!hash) { hash = kzalloc(sizeof(*hash), GFP_KERNEL); if (!hash) { mutex_unlock(&ctx->uring_lock); return ERR_PTR(-ENOMEM); } refcount_set(&hash->refs, 1); init_waitqueue_head(&hash->wait); ctx->hash_map = hash; } mutex_unlock(&ctx->uring_lock); data.hash = hash; data.task = task; data.free_work = io_wq_free_work; data.do_work = io_wq_submit_work; /* Do QD, or 4 * CPUS, whatever is smallest */ concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); return io_wq_create(concurrency, &data); } static __cold int io_uring_alloc_task_context(struct task_struct *task, struct io_ring_ctx *ctx) { struct io_uring_task *tctx; int ret; tctx = kzalloc(sizeof(*tctx), GFP_KERNEL); if (unlikely(!tctx)) return -ENOMEM; tctx->registered_rings = kcalloc(IO_RINGFD_REG_MAX, sizeof(struct file *), GFP_KERNEL); if (unlikely(!tctx->registered_rings)) { kfree(tctx); return -ENOMEM; } ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); if (unlikely(ret)) { kfree(tctx->registered_rings); kfree(tctx); return ret; } tctx->io_wq = io_init_wq_offload(ctx, task); if (IS_ERR(tctx->io_wq)) { ret = PTR_ERR(tctx->io_wq); percpu_counter_destroy(&tctx->inflight); kfree(tctx->registered_rings); kfree(tctx); return ret; } xa_init(&tctx->xa); init_waitqueue_head(&tctx->wait); atomic_set(&tctx->in_idle, 0); task->io_uring = tctx; spin_lock_init(&tctx->task_lock); INIT_WQ_LIST(&tctx->task_list); INIT_WQ_LIST(&tctx->prior_task_list); init_task_work(&tctx->task_work, tctx_task_work); return 0; } void __io_uring_free(struct task_struct *tsk) { struct io_uring_task *tctx = tsk->io_uring; WARN_ON_ONCE(!xa_empty(&tctx->xa)); WARN_ON_ONCE(tctx->io_wq); WARN_ON_ONCE(tctx->cached_refs); kfree(tctx->registered_rings); percpu_counter_destroy(&tctx->inflight); kfree(tctx); tsk->io_uring = NULL; } static __cold int io_sq_offload_create(struct io_ring_ctx *ctx, struct io_uring_params *p) { int ret; /* Retain compatibility with failing for an invalid attach attempt */ if ((ctx->flags & (IORING_SETUP_ATTACH_WQ | IORING_SETUP_SQPOLL)) == IORING_SETUP_ATTACH_WQ) { struct fd f; f = fdget(p->wq_fd); if (!f.file) return -ENXIO; if (f.file->f_op != &io_uring_fops) { fdput(f); return -EINVAL; } fdput(f); } if (ctx->flags & IORING_SETUP_SQPOLL) { struct task_struct *tsk; struct io_sq_data *sqd; bool attached; ret = security_uring_sqpoll(); if (ret) return ret; sqd = io_get_sq_data(p, &attached); if (IS_ERR(sqd)) { ret = PTR_ERR(sqd); goto err; } ctx->sq_creds = get_current_cred(); ctx->sq_data = sqd; ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle); if (!ctx->sq_thread_idle) ctx->sq_thread_idle = HZ; io_sq_thread_park(sqd); list_add(&ctx->sqd_list, &sqd->ctx_list); io_sqd_update_thread_idle(sqd); /* don't attach to a dying SQPOLL thread, would be racy */ ret = (attached && !sqd->thread) ? -ENXIO : 0; io_sq_thread_unpark(sqd); if (ret < 0) goto err; if (attached) return 0; if (p->flags & IORING_SETUP_SQ_AFF) { int cpu = p->sq_thread_cpu; ret = -EINVAL; if (cpu >= nr_cpu_ids || !cpu_online(cpu)) goto err_sqpoll; sqd->sq_cpu = cpu; } else { sqd->sq_cpu = -1; } sqd->task_pid = current->pid; sqd->task_tgid = current->tgid; tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE); if (IS_ERR(tsk)) { ret = PTR_ERR(tsk); goto err_sqpoll; } sqd->thread = tsk; ret = io_uring_alloc_task_context(tsk, ctx); wake_up_new_task(tsk); if (ret) goto err; } else if (p->flags & IORING_SETUP_SQ_AFF) { /* Can't have SQ_AFF without SQPOLL */ ret = -EINVAL; goto err; } return 0; err_sqpoll: complete(&ctx->sq_data->exited); err: io_sq_thread_finish(ctx); return ret; } static inline void __io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) { atomic_long_sub(nr_pages, &user->locked_vm); } static inline int __io_account_mem(struct user_struct *user, unsigned long nr_pages) { unsigned long page_limit, cur_pages, new_pages; /* Don't allow more pages than we can safely lock */ page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; do { cur_pages = atomic_long_read(&user->locked_vm); new_pages = cur_pages + nr_pages; if (new_pages > page_limit) return -ENOMEM; } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, new_pages) != cur_pages); return 0; } static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) { if (ctx->user) __io_unaccount_mem(ctx->user, nr_pages); if (ctx->mm_account) atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); } static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) { int ret; if (ctx->user) { ret = __io_account_mem(ctx->user, nr_pages); if (ret) return ret; } if (ctx->mm_account) atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); return 0; } static void io_mem_free(void *ptr) { struct page *page; if (!ptr) return; page = virt_to_head_page(ptr); if (put_page_testzero(page)) free_compound_page(page); } static void *io_mem_alloc(size_t size) { gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP; return (void *) __get_free_pages(gfp, get_order(size)); } static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries, size_t *sq_offset) { struct io_rings *rings; size_t off, sq_array_size; off = struct_size(rings, cqes, cq_entries); if (off == SIZE_MAX) return SIZE_MAX; #ifdef CONFIG_SMP off = ALIGN(off, SMP_CACHE_BYTES); if (off == 0) return SIZE_MAX; #endif if (sq_offset) *sq_offset = off; sq_array_size = array_size(sizeof(u32), sq_entries); if (sq_array_size == SIZE_MAX) return SIZE_MAX; if (check_add_overflow(off, sq_array_size, &off)) return SIZE_MAX; return off; } static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot) { struct io_mapped_ubuf *imu = *slot; unsigned int i; if (imu != ctx->dummy_ubuf) { for (i = 0; i < imu->nr_bvecs; i++) unpin_user_page(imu->bvec[i].bv_page); if (imu->acct_pages) io_unaccount_mem(ctx, imu->acct_pages); kvfree(imu); } *slot = NULL; } static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) { io_buffer_unmap(ctx, &prsrc->buf); prsrc->buf = NULL; } static void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx) { unsigned int i; for (i = 0; i < ctx->nr_user_bufs; i++) io_buffer_unmap(ctx, &ctx->user_bufs[i]); kfree(ctx->user_bufs); io_rsrc_data_free(ctx->buf_data); ctx->user_bufs = NULL; ctx->buf_data = NULL; ctx->nr_user_bufs = 0; } static int io_sqe_buffers_unregister(struct io_ring_ctx *ctx) { int ret; if (!ctx->buf_data) return -ENXIO; ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx); if (!ret) __io_sqe_buffers_unregister(ctx); return ret; } static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, void __user *arg, unsigned index) { struct iovec __user *src; #ifdef CONFIG_COMPAT if (ctx->compat) { struct compat_iovec __user *ciovs; struct compat_iovec ciov; ciovs = (struct compat_iovec __user *) arg; if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) return -EFAULT; dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); dst->iov_len = ciov.iov_len; return 0; } #endif src = (struct iovec __user *) arg; if (copy_from_user(dst, &src[index], sizeof(*dst))) return -EFAULT; return 0; } /* * Not super efficient, but this is just a registration time. And we do cache * the last compound head, so generally we'll only do a full search if we don't * match that one. * * We check if the given compound head page has already been accounted, to * avoid double accounting it. This allows us to account the full size of the * page, not just the constituent pages of a huge page. */ static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages, int nr_pages, struct page *hpage) { int i, j; /* check current page array */ for (i = 0; i < nr_pages; i++) { if (!PageCompound(pages[i])) continue; if (compound_head(pages[i]) == hpage) return true; } /* check previously registered pages */ for (i = 0; i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *imu = ctx->user_bufs[i]; for (j = 0; j < imu->nr_bvecs; j++) { if (!PageCompound(imu->bvec[j].bv_page)) continue; if (compound_head(imu->bvec[j].bv_page) == hpage) return true; } } return false; } static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, int nr_pages, struct io_mapped_ubuf *imu, struct page **last_hpage) { int i, ret; imu->acct_pages = 0; for (i = 0; i < nr_pages; i++) { if (!PageCompound(pages[i])) { imu->acct_pages++; } else { struct page *hpage; hpage = compound_head(pages[i]); if (hpage == *last_hpage) continue; *last_hpage = hpage; if (headpage_already_acct(ctx, pages, i, hpage)) continue; imu->acct_pages += page_size(hpage) >> PAGE_SHIFT; } } if (!imu->acct_pages) return 0; ret = io_account_mem(ctx, imu->acct_pages); if (ret) imu->acct_pages = 0; return ret; } static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, struct io_mapped_ubuf **pimu, struct page **last_hpage) { struct io_mapped_ubuf *imu = NULL; struct vm_area_struct **vmas = NULL; struct page **pages = NULL; unsigned long off, start, end, ubuf; size_t size; int ret, pret, nr_pages, i; if (!iov->iov_base) { *pimu = ctx->dummy_ubuf; return 0; } ubuf = (unsigned long) iov->iov_base; end = (ubuf + iov->iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; start = ubuf >> PAGE_SHIFT; nr_pages = end - start; *pimu = NULL; ret = -ENOMEM; pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); if (!pages) goto done; vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *), GFP_KERNEL); if (!vmas) goto done; imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL); if (!imu) goto done; ret = 0; mmap_read_lock(current->mm); pret = pin_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages, vmas); if (pret == nr_pages) { /* don't support file backed memory */ for (i = 0; i < nr_pages; i++) { struct vm_area_struct *vma = vmas[i]; if (vma_is_shmem(vma)) continue; if (vma->vm_file && !is_file_hugepages(vma->vm_file)) { ret = -EOPNOTSUPP; break; } } } else { ret = pret < 0 ? pret : -EFAULT; } mmap_read_unlock(current->mm); if (ret) { /* * if we did partial map, or found file backed vmas, * release any pages we did get */ if (pret > 0) unpin_user_pages(pages, pret); goto done; } ret = io_buffer_account_pin(ctx, pages, pret, imu, last_hpage); if (ret) { unpin_user_pages(pages, pret); goto done; } off = ubuf & ~PAGE_MASK; size = iov->iov_len; for (i = 0; i < nr_pages; i++) { size_t vec_len; vec_len = min_t(size_t, size, PAGE_SIZE - off); imu->bvec[i].bv_page = pages[i]; imu->bvec[i].bv_len = vec_len; imu->bvec[i].bv_offset = off; off = 0; size -= vec_len; } /* store original address for later verification */ imu->ubuf = ubuf; imu->ubuf_end = ubuf + iov->iov_len; imu->nr_bvecs = nr_pages; *pimu = imu; ret = 0; done: if (ret) kvfree(imu); kvfree(pages); kvfree(vmas); return ret; } static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args) { ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL); return ctx->user_bufs ? 0 : -ENOMEM; } static int io_buffer_validate(struct iovec *iov) { unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1); /* * Don't impose further limits on the size and buffer * constraints here, we'll -EINVAL later when IO is * submitted if they are wrong. */ if (!iov->iov_base) return iov->iov_len ? -EFAULT : 0; if (!iov->iov_len) return -EFAULT; /* arbitrary limit, but we need something */ if (iov->iov_len > SZ_1G) return -EFAULT; if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp)) return -EOVERFLOW; return 0; } static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, unsigned int nr_args, u64 __user *tags) { struct page *last_hpage = NULL; struct io_rsrc_data *data; int i, ret; struct iovec iov; if (ctx->user_bufs) return -EBUSY; if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS) return -EINVAL; ret = io_rsrc_node_switch_start(ctx); if (ret) return ret; ret = io_rsrc_data_alloc(ctx, io_rsrc_buf_put, tags, nr_args, &data); if (ret) return ret; ret = io_buffers_map_alloc(ctx, nr_args); if (ret) { io_rsrc_data_free(data); return ret; } for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) { ret = io_copy_iov(ctx, &iov, arg, i); if (ret) break; ret = io_buffer_validate(&iov); if (ret) break; if (!iov.iov_base && *io_get_tag_slot(data, i)) { ret = -EINVAL; break; } ret = io_sqe_buffer_register(ctx, &iov, &ctx->user_bufs[i], &last_hpage); if (ret) break; } WARN_ON_ONCE(ctx->buf_data); ctx->buf_data = data; if (ret) __io_sqe_buffers_unregister(ctx); else io_rsrc_node_switch(ctx, NULL); return ret; } static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, struct io_uring_rsrc_update2 *up, unsigned int nr_args) { u64 __user *tags = u64_to_user_ptr(up->tags); struct iovec iov, __user *iovs = u64_to_user_ptr(up->data); struct page *last_hpage = NULL; bool needs_switch = false; __u32 done; int i, err; if (!ctx->buf_data) return -ENXIO; if (up->offset + nr_args > ctx->nr_user_bufs) return -EINVAL; for (done = 0; done < nr_args; done++) { struct io_mapped_ubuf *imu; int offset = up->offset + done; u64 tag = 0; err = io_copy_iov(ctx, &iov, iovs, done); if (err) break; if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) { err = -EFAULT; break; } err = io_buffer_validate(&iov); if (err) break; if (!iov.iov_base && tag) { err = -EINVAL; break; } err = io_sqe_buffer_register(ctx, &iov, &imu, &last_hpage); if (err) break; i = array_index_nospec(offset, ctx->nr_user_bufs); if (ctx->user_bufs[i] != ctx->dummy_ubuf) { err = io_queue_rsrc_removal(ctx->buf_data, i, ctx->rsrc_node, ctx->user_bufs[i]); if (unlikely(err)) { io_buffer_unmap(ctx, &imu); break; } ctx->user_bufs[i] = NULL; needs_switch = true; } ctx->user_bufs[i] = imu; *io_get_tag_slot(ctx->buf_data, offset) = tag; } if (needs_switch) io_rsrc_node_switch(ctx, ctx->buf_data); return done ? done : err; } static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg, unsigned int eventfd_async) { struct io_ev_fd *ev_fd; __s32 __user *fds = arg; int fd; ev_fd = rcu_dereference_protected(ctx->io_ev_fd, lockdep_is_held(&ctx->uring_lock)); if (ev_fd) return -EBUSY; if (copy_from_user(&fd, fds, sizeof(*fds))) return -EFAULT; ev_fd = kmalloc(sizeof(*ev_fd), GFP_KERNEL); if (!ev_fd) return -ENOMEM; ev_fd->cq_ev_fd = eventfd_ctx_fdget(fd); if (IS_ERR(ev_fd->cq_ev_fd)) { int ret = PTR_ERR(ev_fd->cq_ev_fd); kfree(ev_fd); return ret; } ev_fd->eventfd_async = eventfd_async; ctx->has_evfd = true; rcu_assign_pointer(ctx->io_ev_fd, ev_fd); return 0; } static void io_eventfd_put(struct rcu_head *rcu) { struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu); eventfd_ctx_put(ev_fd->cq_ev_fd); kfree(ev_fd); } static int io_eventfd_unregister(struct io_ring_ctx *ctx) { struct io_ev_fd *ev_fd; ev_fd = rcu_dereference_protected(ctx->io_ev_fd, lockdep_is_held(&ctx->uring_lock)); if (ev_fd) { ctx->has_evfd = false; rcu_assign_pointer(ctx->io_ev_fd, NULL); call_rcu(&ev_fd->rcu, io_eventfd_put); return 0; } return -ENXIO; } static void io_destroy_buffers(struct io_ring_ctx *ctx) { int i; for (i = 0; i < (1U << IO_BUFFERS_HASH_BITS); i++) { struct list_head *list = &ctx->io_buffers[i]; while (!list_empty(list)) { struct io_buffer_list *bl; bl = list_first_entry(list, struct io_buffer_list, list); __io_remove_buffers(ctx, bl, -1U); list_del(&bl->list); kfree(bl); } } while (!list_empty(&ctx->io_buffers_pages)) { struct page *page; page = list_first_entry(&ctx->io_buffers_pages, struct page, lru); list_del_init(&page->lru); __free_page(page); } } static void io_req_caches_free(struct io_ring_ctx *ctx) { struct io_submit_state *state = &ctx->submit_state; int nr = 0; mutex_lock(&ctx->uring_lock); io_flush_cached_locked_reqs(ctx, state); while (state->free_list.next) { struct io_wq_work_node *node; struct io_kiocb *req; node = wq_stack_extract(&state->free_list); req = container_of(node, struct io_kiocb, comp_list); kmem_cache_free(req_cachep, req); nr++; } if (nr) percpu_ref_put_many(&ctx->refs, nr); mutex_unlock(&ctx->uring_lock); } static void io_wait_rsrc_data(struct io_rsrc_data *data) { if (data && !atomic_dec_and_test(&data->refs)) wait_for_completion(&data->done); } static void io_flush_apoll_cache(struct io_ring_ctx *ctx) { struct async_poll *apoll; while (!list_empty(&ctx->apoll_cache)) { apoll = list_first_entry(&ctx->apoll_cache, struct async_poll, poll.wait.entry); list_del(&apoll->poll.wait.entry); kfree(apoll); } } static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx) { io_sq_thread_finish(ctx); if (ctx->mm_account) { mmdrop(ctx->mm_account); ctx->mm_account = NULL; } io_rsrc_refs_drop(ctx); /* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */ io_wait_rsrc_data(ctx->buf_data); io_wait_rsrc_data(ctx->file_data); mutex_lock(&ctx->uring_lock); if (ctx->buf_data) __io_sqe_buffers_unregister(ctx); if (ctx->file_data) __io_sqe_files_unregister(ctx); if (ctx->rings) __io_cqring_overflow_flush(ctx, true); io_eventfd_unregister(ctx); io_flush_apoll_cache(ctx); mutex_unlock(&ctx->uring_lock); io_destroy_buffers(ctx); if (ctx->sq_creds) put_cred(ctx->sq_creds); /* there are no registered resources left, nobody uses it */ if (ctx->rsrc_node) io_rsrc_node_destroy(ctx->rsrc_node); if (ctx->rsrc_backup_node) io_rsrc_node_destroy(ctx->rsrc_backup_node); flush_delayed_work(&ctx->rsrc_put_work); flush_delayed_work(&ctx->fallback_work); WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list)); WARN_ON_ONCE(!llist_empty(&ctx->rsrc_put_llist)); #if defined(CONFIG_UNIX) if (ctx->ring_sock) { ctx->ring_sock->file = NULL; /* so that iput() is called */ sock_release(ctx->ring_sock); } #endif WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list)); io_mem_free(ctx->rings); io_mem_free(ctx->sq_sqes); percpu_ref_exit(&ctx->refs); free_uid(ctx->user); io_req_caches_free(ctx); if (ctx->hash_map) io_wq_put_hash(ctx->hash_map); kfree(ctx->cancel_hash); kfree(ctx->dummy_ubuf); kfree(ctx->io_buffers); kfree(ctx); } static __poll_t io_uring_poll(struct file *file, poll_table *wait) { struct io_ring_ctx *ctx = file->private_data; __poll_t mask = 0; poll_wait(file, &ctx->cq_wait, wait); /* * synchronizes with barrier from wq_has_sleeper call in * io_commit_cqring */ smp_rmb(); if (!io_sqring_full(ctx)) mask |= EPOLLOUT | EPOLLWRNORM; /* * Don't flush cqring overflow list here, just do a simple check. * Otherwise there could possible be ABBA deadlock: * CPU0 CPU1 * ---- ---- * lock(&ctx->uring_lock); * lock(&ep->mtx); * lock(&ctx->uring_lock); * lock(&ep->mtx); * * Users may get EPOLLIN meanwhile seeing nothing in cqring, this * pushs them to do the flush. */ if (io_cqring_events(ctx) || test_bit(0, &ctx->check_cq_overflow)) mask |= EPOLLIN | EPOLLRDNORM; return mask; } static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id) { const struct cred *creds; creds = xa_erase(&ctx->personalities, id); if (creds) { put_cred(creds); return 0; } return -EINVAL; } struct io_tctx_exit { struct callback_head task_work; struct completion completion; struct io_ring_ctx *ctx; }; static __cold void io_tctx_exit_cb(struct callback_head *cb) { struct io_uring_task *tctx = current->io_uring; struct io_tctx_exit *work; work = container_of(cb, struct io_tctx_exit, task_work); /* * When @in_idle, we're in cancellation and it's racy to remove the * node. It'll be removed by the end of cancellation, just ignore it. */ if (!atomic_read(&tctx->in_idle)) io_uring_del_tctx_node((unsigned long)work->ctx); complete(&work->completion); } static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); return req->ctx == data; } static __cold void io_ring_exit_work(struct work_struct *work) { struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work); unsigned long timeout = jiffies + HZ * 60 * 5; unsigned long interval = HZ / 20; struct io_tctx_exit exit; struct io_tctx_node *node; int ret; /* * If we're doing polled IO and end up having requests being * submitted async (out-of-line), then completions can come in while * we're waiting for refs to drop. We need to reap these manually, * as nobody else will be looking for them. */ do { io_uring_try_cancel_requests(ctx, NULL, true); if (ctx->sq_data) { struct io_sq_data *sqd = ctx->sq_data; struct task_struct *tsk; io_sq_thread_park(sqd); tsk = sqd->thread; if (tsk && tsk->io_uring && tsk->io_uring->io_wq) io_wq_cancel_cb(tsk->io_uring->io_wq, io_cancel_ctx_cb, ctx, true); io_sq_thread_unpark(sqd); } io_req_caches_free(ctx); if (WARN_ON_ONCE(time_after(jiffies, timeout))) { /* there is little hope left, don't run it too often */ interval = HZ * 60; } } while (!wait_for_completion_timeout(&ctx->ref_comp, interval)); init_completion(&exit.completion); init_task_work(&exit.task_work, io_tctx_exit_cb); exit.ctx = ctx; /* * Some may use context even when all refs and requests have been put, * and they are free to do so while still holding uring_lock or * completion_lock, see io_req_task_submit(). Apart from other work, * this lock/unlock section also waits them to finish. */ mutex_lock(&ctx->uring_lock); while (!list_empty(&ctx->tctx_list)) { WARN_ON_ONCE(time_after(jiffies, timeout)); node = list_first_entry(&ctx->tctx_list, struct io_tctx_node, ctx_node); /* don't spin on a single task if cancellation failed */ list_rotate_left(&ctx->tctx_list); ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL); if (WARN_ON_ONCE(ret)) continue; mutex_unlock(&ctx->uring_lock); wait_for_completion(&exit.completion); mutex_lock(&ctx->uring_lock); } mutex_unlock(&ctx->uring_lock); spin_lock(&ctx->completion_lock); spin_unlock(&ctx->completion_lock); io_ring_ctx_free(ctx); } /* Returns true if we found and killed one or more timeouts */ static __cold bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk, bool cancel_all) { struct io_kiocb *req, *tmp; int canceled = 0; spin_lock(&ctx->completion_lock); spin_lock_irq(&ctx->timeout_lock); list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) { if (io_match_task(req, tsk, cancel_all)) { io_kill_timeout(req, -ECANCELED); canceled++; } } spin_unlock_irq(&ctx->timeout_lock); if (canceled != 0) io_commit_cqring(ctx); spin_unlock(&ctx->completion_lock); if (canceled != 0) io_cqring_ev_posted(ctx); return canceled != 0; } static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) { unsigned long index; struct creds *creds; mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); if (ctx->rings) __io_cqring_overflow_flush(ctx, true); xa_for_each(&ctx->personalities, index, creds) io_unregister_personality(ctx, index); mutex_unlock(&ctx->uring_lock); io_kill_timeouts(ctx, NULL, true); io_poll_remove_all(ctx, NULL, true); /* if we failed setting up the ctx, we might not have any rings */ io_iopoll_try_reap_events(ctx); INIT_WORK(&ctx->exit_work, io_ring_exit_work); /* * Use system_unbound_wq to avoid spawning tons of event kworkers * if we're exiting a ton of rings at the same time. It just adds * noise and overhead, there's no discernable change in runtime * over using system_wq. */ queue_work(system_unbound_wq, &ctx->exit_work); } static int io_uring_release(struct inode *inode, struct file *file) { struct io_ring_ctx *ctx = file->private_data; file->private_data = NULL; io_ring_ctx_wait_and_kill(ctx); return 0; } struct io_task_cancel { struct task_struct *task; bool all; }; static bool io_cancel_task_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct io_task_cancel *cancel = data; return io_match_task_safe(req, cancel->task, cancel->all); } static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx, struct task_struct *task, bool cancel_all) { struct io_defer_entry *de; LIST_HEAD(list); spin_lock(&ctx->completion_lock); list_for_each_entry_reverse(de, &ctx->defer_list, list) { if (io_match_task_safe(de->req, task, cancel_all)) { list_cut_position(&list, &ctx->defer_list, &de->list); break; } } spin_unlock(&ctx->completion_lock); if (list_empty(&list)) return false; while (!list_empty(&list)) { de = list_first_entry(&list, struct io_defer_entry, list); list_del_init(&de->list); io_req_complete_failed(de->req, -ECANCELED); kfree(de); } return true; } static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx) { struct io_tctx_node *node; enum io_wq_cancel cret; bool ret = false; mutex_lock(&ctx->uring_lock); list_for_each_entry(node, &ctx->tctx_list, ctx_node) { struct io_uring_task *tctx = node->task->io_uring; /* * io_wq will stay alive while we hold uring_lock, because it's * killed after ctx nodes, which requires to take the lock. */ if (!tctx || !tctx->io_wq) continue; cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true); ret |= (cret != IO_WQ_CANCEL_NOTFOUND); } mutex_unlock(&ctx->uring_lock); return ret; } static __cold void io_uring_try_cancel_requests(struct io_ring_ctx *ctx, struct task_struct *task, bool cancel_all) { struct io_task_cancel cancel = { .task = task, .all = cancel_all, }; struct io_uring_task *tctx = task ? task->io_uring : NULL; while (1) { enum io_wq_cancel cret; bool ret = false; if (!task) { ret |= io_uring_try_cancel_iowq(ctx); } else if (tctx && tctx->io_wq) { /* * Cancels requests of all rings, not only @ctx, but * it's fine as the task is in exit/exec. */ cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb, &cancel, true); ret |= (cret != IO_WQ_CANCEL_NOTFOUND); } /* SQPOLL thread does its own polling */ if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) || (ctx->sq_data && ctx->sq_data->thread == current)) { while (!wq_list_empty(&ctx->iopoll_list)) { io_iopoll_try_reap_events(ctx); ret = true; } } ret |= io_cancel_defer_files(ctx, task, cancel_all); ret |= io_poll_remove_all(ctx, task, cancel_all); ret |= io_kill_timeouts(ctx, task, cancel_all); if (task) ret |= io_run_task_work(); if (!ret) break; cond_resched(); } } static int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) { struct io_uring_task *tctx = current->io_uring; struct io_tctx_node *node; int ret; if (unlikely(!tctx)) { ret = io_uring_alloc_task_context(current, ctx); if (unlikely(ret)) return ret; tctx = current->io_uring; if (ctx->iowq_limits_set) { unsigned int limits[2] = { ctx->iowq_limits[0], ctx->iowq_limits[1], }; ret = io_wq_max_workers(tctx->io_wq, limits); if (ret) return ret; } } if (!xa_load(&tctx->xa, (unsigned long)ctx)) { node = kmalloc(sizeof(*node), GFP_KERNEL); if (!node) return -ENOMEM; node->ctx = ctx; node->task = current; ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx, node, GFP_KERNEL)); if (ret) { kfree(node); return ret; } mutex_lock(&ctx->uring_lock); list_add(&node->ctx_node, &ctx->tctx_list); mutex_unlock(&ctx->uring_lock); } tctx->last = ctx; return 0; } /* * Note that this task has used io_uring. We use it for cancelation purposes. */ static inline int io_uring_add_tctx_node(struct io_ring_ctx *ctx) { struct io_uring_task *tctx = current->io_uring; if (likely(tctx && tctx->last == ctx)) return 0; return __io_uring_add_tctx_node(ctx); } /* * Remove this io_uring_file -> task mapping. */ static __cold void io_uring_del_tctx_node(unsigned long index) { struct io_uring_task *tctx = current->io_uring; struct io_tctx_node *node; if (!tctx) return; node = xa_erase(&tctx->xa, index); if (!node) return; WARN_ON_ONCE(current != node->task); WARN_ON_ONCE(list_empty(&node->ctx_node)); mutex_lock(&node->ctx->uring_lock); list_del(&node->ctx_node); mutex_unlock(&node->ctx->uring_lock); if (tctx->last == node->ctx) tctx->last = NULL; kfree(node); } static __cold void io_uring_clean_tctx(struct io_uring_task *tctx) { struct io_wq *wq = tctx->io_wq; struct io_tctx_node *node; unsigned long index; xa_for_each(&tctx->xa, index, node) { io_uring_del_tctx_node(index); cond_resched(); } if (wq) { /* * Must be after io_uring_del_tctx_node() (removes nodes under * uring_lock) to avoid race with io_uring_try_cancel_iowq(). */ io_wq_put_and_exit(wq); tctx->io_wq = NULL; } } static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked) { if (tracked) return 0; return percpu_counter_sum(&tctx->inflight); } /* * Find any io_uring ctx that this task has registered or done IO on, and cancel * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation. */ static __cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd) { struct io_uring_task *tctx = current->io_uring; struct io_ring_ctx *ctx; s64 inflight; DEFINE_WAIT(wait); WARN_ON_ONCE(sqd && sqd->thread != current); if (!current->io_uring) return; if (tctx->io_wq) io_wq_exit_start(tctx->io_wq); atomic_inc(&tctx->in_idle); do { io_uring_drop_tctx_refs(current); /* read completions before cancelations */ inflight = tctx_inflight(tctx, !cancel_all); if (!inflight) break; if (!sqd) { struct io_tctx_node *node; unsigned long index; xa_for_each(&tctx->xa, index, node) { /* sqpoll task will cancel all its requests */ if (node->ctx->sq_data) continue; io_uring_try_cancel_requests(node->ctx, current, cancel_all); } } else { list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) io_uring_try_cancel_requests(ctx, current, cancel_all); } prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE); io_run_task_work(); io_uring_drop_tctx_refs(current); /* * If we've seen completions, retry without waiting. This * avoids a race where a completion comes in before we did * prepare_to_wait(). */ if (inflight == tctx_inflight(tctx, !cancel_all)) schedule(); finish_wait(&tctx->wait, &wait); } while (1); io_uring_clean_tctx(tctx); if (cancel_all) { /* * We shouldn't run task_works after cancel, so just leave * ->in_idle set for normal exit. */ atomic_dec(&tctx->in_idle); /* for exec all current's requests should be gone, kill tctx */ __io_uring_free(current); } } void __io_uring_cancel(bool cancel_all) { io_uring_cancel_generic(cancel_all, NULL); } void io_uring_unreg_ringfd(void) { struct io_uring_task *tctx = current->io_uring; int i; for (i = 0; i < IO_RINGFD_REG_MAX; i++) { if (tctx->registered_rings[i]) { fput(tctx->registered_rings[i]); tctx->registered_rings[i] = NULL; } } } static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, int start, int end) { struct file *file; int offset; for (offset = start; offset < end; offset++) { offset = array_index_nospec(offset, IO_RINGFD_REG_MAX); if (tctx->registered_rings[offset]) continue; file = fget(fd); if (!file) { return -EBADF; } else if (file->f_op != &io_uring_fops) { fput(file); return -EOPNOTSUPP; } tctx->registered_rings[offset] = file; return offset; } return -EBUSY; } /* * Register a ring fd to avoid fdget/fdput for each io_uring_enter() * invocation. User passes in an array of struct io_uring_rsrc_update * with ->data set to the ring_fd, and ->offset given for the desired * index. If no index is desired, application may set ->offset == -1U * and we'll find an available index. Returns number of entries * successfully processed, or < 0 on error if none were processed. */ static int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, unsigned nr_args) { struct io_uring_rsrc_update __user *arg = __arg; struct io_uring_rsrc_update reg; struct io_uring_task *tctx; int ret, i; if (!nr_args || nr_args > IO_RINGFD_REG_MAX) return -EINVAL; mutex_unlock(&ctx->uring_lock); ret = io_uring_add_tctx_node(ctx); mutex_lock(&ctx->uring_lock); if (ret) return ret; tctx = current->io_uring; for (i = 0; i < nr_args; i++) { int start, end; if (copy_from_user(®, &arg[i], sizeof(reg))) { ret = -EFAULT; break; } if (reg.offset == -1U) { start = 0; end = IO_RINGFD_REG_MAX; } else { if (reg.offset >= IO_RINGFD_REG_MAX) { ret = -EINVAL; break; } start = reg.offset; end = start + 1; } ret = io_ring_add_registered_fd(tctx, reg.data, start, end); if (ret < 0) break; reg.offset = ret; if (copy_to_user(&arg[i], ®, sizeof(reg))) { fput(tctx->registered_rings[reg.offset]); tctx->registered_rings[reg.offset] = NULL; ret = -EFAULT; break; } } return i ? i : ret; } static int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, unsigned nr_args) { struct io_uring_rsrc_update __user *arg = __arg; struct io_uring_task *tctx = current->io_uring; struct io_uring_rsrc_update reg; int ret = 0, i; if (!nr_args || nr_args > IO_RINGFD_REG_MAX) return -EINVAL; if (!tctx) return 0; for (i = 0; i < nr_args; i++) { if (copy_from_user(®, &arg[i], sizeof(reg))) { ret = -EFAULT; break; } if (reg.offset >= IO_RINGFD_REG_MAX) { ret = -EINVAL; break; } reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); if (tctx->registered_rings[reg.offset]) { fput(tctx->registered_rings[reg.offset]); tctx->registered_rings[reg.offset] = NULL; } } return i ? i : ret; } static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff, size_t sz) { struct io_ring_ctx *ctx = file->private_data; loff_t offset = pgoff << PAGE_SHIFT; struct page *page; void *ptr; switch (offset) { case IORING_OFF_SQ_RING: case IORING_OFF_CQ_RING: ptr = ctx->rings; break; case IORING_OFF_SQES: ptr = ctx->sq_sqes; break; default: return ERR_PTR(-EINVAL); } page = virt_to_head_page(ptr); if (sz > page_size(page)) return ERR_PTR(-EINVAL); return ptr; } #ifdef CONFIG_MMU static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { size_t sz = vma->vm_end - vma->vm_start; unsigned long pfn; void *ptr; ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz); if (IS_ERR(ptr)) return PTR_ERR(ptr); pfn = virt_to_phys(ptr) >> PAGE_SHIFT; return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); } #else /* !CONFIG_MMU */ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL; } static unsigned int io_uring_nommu_mmap_capabilities(struct file *file) { return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; } static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { void *ptr; ptr = io_uring_validate_mmap_request(file, pgoff, len); if (IS_ERR(ptr)) return PTR_ERR(ptr); return (unsigned long) ptr; } #endif /* !CONFIG_MMU */ static int io_sqpoll_wait_sq(struct io_ring_ctx *ctx) { DEFINE_WAIT(wait); do { if (!io_sqring_full(ctx)) break; prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE); if (!io_sqring_full(ctx)) break; schedule(); } while (!signal_pending(current)); finish_wait(&ctx->sqo_sq_wait, &wait); return 0; } static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz, struct __kernel_timespec __user **ts, const sigset_t __user **sig) { struct io_uring_getevents_arg arg; /* * If EXT_ARG isn't set, then we have no timespec and the argp pointer * is just a pointer to the sigset_t. */ if (!(flags & IORING_ENTER_EXT_ARG)) { *sig = (const sigset_t __user *) argp; *ts = NULL; return 0; } /* * EXT_ARG is set - ensure we agree on the size of it and copy in our * timespec and sigset_t pointers if good. */ if (*argsz != sizeof(arg)) return -EINVAL; if (copy_from_user(&arg, argp, sizeof(arg))) return -EFAULT; *sig = u64_to_user_ptr(arg.sigmask); *argsz = arg.sigmask_sz; *ts = u64_to_user_ptr(arg.ts); return 0; } SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, u32, min_complete, u32, flags, const void __user *, argp, size_t, argsz) { struct io_ring_ctx *ctx; int submitted = 0; struct fd f; long ret; io_run_task_work(); if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP | IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG | IORING_ENTER_REGISTERED_RING))) return -EINVAL; /* * Ring fd has been registered via IORING_REGISTER_RING_FDS, we * need only dereference our task private array to find it. */ if (flags & IORING_ENTER_REGISTERED_RING) { struct io_uring_task *tctx = current->io_uring; if (!tctx || fd >= IO_RINGFD_REG_MAX) return -EINVAL; fd = array_index_nospec(fd, IO_RINGFD_REG_MAX); f.file = tctx->registered_rings[fd]; if (unlikely(!f.file)) return -EBADF; } else { f = fdget(fd); if (unlikely(!f.file)) return -EBADF; } ret = -EOPNOTSUPP; if (unlikely(f.file->f_op != &io_uring_fops)) goto out_fput; ret = -ENXIO; ctx = f.file->private_data; if (unlikely(!percpu_ref_tryget(&ctx->refs))) goto out_fput; ret = -EBADFD; if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED)) goto out; /* * For SQ polling, the thread will do all submissions and completions. * Just return the requested submit count, and wake the thread if * we were asked to. */ ret = 0; if (ctx->flags & IORING_SETUP_SQPOLL) { io_cqring_overflow_flush(ctx); if (unlikely(ctx->sq_data->thread == NULL)) { ret = -EOWNERDEAD; goto out; } if (flags & IORING_ENTER_SQ_WAKEUP) wake_up(&ctx->sq_data->wait); if (flags & IORING_ENTER_SQ_WAIT) { ret = io_sqpoll_wait_sq(ctx); if (ret) goto out; } submitted = to_submit; } else if (to_submit) { ret = io_uring_add_tctx_node(ctx); if (unlikely(ret)) goto out; mutex_lock(&ctx->uring_lock); submitted = io_submit_sqes(ctx, to_submit); mutex_unlock(&ctx->uring_lock); if (submitted != to_submit) goto out; } if (flags & IORING_ENTER_GETEVENTS) { const sigset_t __user *sig; struct __kernel_timespec __user *ts; ret = io_get_ext_arg(flags, argp, &argsz, &ts, &sig); if (unlikely(ret)) goto out; min_complete = min(min_complete, ctx->cq_entries); /* * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user * space applications don't need to do io completion events * polling again, they can rely on io_sq_thread to do polling * work, which can reduce cpu usage and uring_lock contention. */ if (ctx->flags & IORING_SETUP_IOPOLL && !(ctx->flags & IORING_SETUP_SQPOLL)) { ret = io_iopoll_check(ctx, min_complete); } else { ret = io_cqring_wait(ctx, min_complete, sig, argsz, ts); } } out: percpu_ref_put(&ctx->refs); out_fput: if (!(flags & IORING_ENTER_REGISTERED_RING)) fdput(f); return submitted ? submitted : ret; } #ifdef CONFIG_PROC_FS static __cold int io_uring_show_cred(struct seq_file *m, unsigned int id, const struct cred *cred) { struct user_namespace *uns = seq_user_ns(m); struct group_info *gi; kernel_cap_t cap; unsigned __capi; int g; seq_printf(m, "%5d\n", id); seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid)); seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid)); seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid)); seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid)); seq_puts(m, "\n\tGroups:\t"); gi = cred->group_info; for (g = 0; g < gi->ngroups; g++) { seq_put_decimal_ull(m, g ? " " : "", from_kgid_munged(uns, gi->gid[g])); } seq_puts(m, "\n\tCapEff:\t"); cap = cred->cap_effective; CAP_FOR_EACH_U32(__capi) seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8); seq_putc(m, '\n'); return 0; } static __cold void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) { struct io_sq_data *sq = NULL; struct io_overflow_cqe *ocqe; struct io_rings *r = ctx->rings; unsigned int sq_mask = ctx->sq_entries - 1, cq_mask = ctx->cq_entries - 1; unsigned int sq_head = READ_ONCE(r->sq.head); unsigned int sq_tail = READ_ONCE(r->sq.tail); unsigned int cq_head = READ_ONCE(r->cq.head); unsigned int cq_tail = READ_ONCE(r->cq.tail); unsigned int sq_entries, cq_entries; bool has_lock; unsigned int i; /* * we may get imprecise sqe and cqe info if uring is actively running * since we get cached_sq_head and cached_cq_tail without uring_lock * and sq_tail and cq_head are changed by userspace. But it's ok since * we usually use these info when it is stuck. */ seq_printf(m, "SqMask:\t0x%x\n", sq_mask); seq_printf(m, "SqHead:\t%u\n", sq_head); seq_printf(m, "SqTail:\t%u\n", sq_tail); seq_printf(m, "CachedSqHead:\t%u\n", ctx->cached_sq_head); seq_printf(m, "CqMask:\t0x%x\n", cq_mask); seq_printf(m, "CqHead:\t%u\n", cq_head); seq_printf(m, "CqTail:\t%u\n", cq_tail); seq_printf(m, "CachedCqTail:\t%u\n", ctx->cached_cq_tail); seq_printf(m, "SQEs:\t%u\n", sq_tail - ctx->cached_sq_head); sq_entries = min(sq_tail - sq_head, ctx->sq_entries); for (i = 0; i < sq_entries; i++) { unsigned int entry = i + sq_head; unsigned int sq_idx = READ_ONCE(ctx->sq_array[entry & sq_mask]); struct io_uring_sqe *sqe; if (sq_idx > sq_mask) continue; sqe = &ctx->sq_sqes[sq_idx]; seq_printf(m, "%5u: opcode:%d, fd:%d, flags:%x, user_data:%llu\n", sq_idx, sqe->opcode, sqe->fd, sqe->flags, sqe->user_data); } seq_printf(m, "CQEs:\t%u\n", cq_tail - cq_head); cq_entries = min(cq_tail - cq_head, ctx->cq_entries); for (i = 0; i < cq_entries; i++) { unsigned int entry = i + cq_head; struct io_uring_cqe *cqe = &r->cqes[entry & cq_mask]; seq_printf(m, "%5u: user_data:%llu, res:%d, flag:%x\n", entry & cq_mask, cqe->user_data, cqe->res, cqe->flags); } /* * Avoid ABBA deadlock between the seq lock and the io_uring mutex, * since fdinfo case grabs it in the opposite direction of normal use * cases. If we fail to get the lock, we just don't iterate any * structures that could be going away outside the io_uring mutex. */ has_lock = mutex_trylock(&ctx->uring_lock); if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL)) { sq = ctx->sq_data; if (!sq->thread) sq = NULL; } seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1); seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1); seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files); for (i = 0; has_lock && i < ctx->nr_user_files; i++) { struct file *f = io_file_from_index(ctx, i); if (f) seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname); else seq_printf(m, "%5u: \n", i); } seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs); for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *buf = ctx->user_bufs[i]; unsigned int len = buf->ubuf_end - buf->ubuf; seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, len); } if (has_lock && !xa_empty(&ctx->personalities)) { unsigned long index; const struct cred *cred; seq_printf(m, "Personalities:\n"); xa_for_each(&ctx->personalities, index, cred) io_uring_show_cred(m, index, cred); } if (has_lock) mutex_unlock(&ctx->uring_lock); seq_puts(m, "PollList:\n"); spin_lock(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list = &ctx->cancel_hash[i]; struct io_kiocb *req; hlist_for_each_entry(req, list, hash_node) seq_printf(m, " op=%d, task_works=%d\n", req->opcode, task_work_pending(req->task)); } seq_puts(m, "CqOverflowList:\n"); list_for_each_entry(ocqe, &ctx->cq_overflow_list, list) { struct io_uring_cqe *cqe = &ocqe->cqe; seq_printf(m, " user_data=%llu, res=%d, flags=%x\n", cqe->user_data, cqe->res, cqe->flags); } spin_unlock(&ctx->completion_lock); } static __cold void io_uring_show_fdinfo(struct seq_file *m, struct file *f) { struct io_ring_ctx *ctx = f->private_data; if (percpu_ref_tryget(&ctx->refs)) { __io_uring_show_fdinfo(ctx, m); percpu_ref_put(&ctx->refs); } } #endif static const struct file_operations io_uring_fops = { .release = io_uring_release, .mmap = io_uring_mmap, #ifndef CONFIG_MMU .get_unmapped_area = io_uring_nommu_get_unmapped_area, .mmap_capabilities = io_uring_nommu_mmap_capabilities, #endif .poll = io_uring_poll, #ifdef CONFIG_PROC_FS .show_fdinfo = io_uring_show_fdinfo, #endif }; static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx, struct io_uring_params *p) { struct io_rings *rings; size_t size, sq_array_offset; /* make sure these are sane, as we already accounted them */ ctx->sq_entries = p->sq_entries; ctx->cq_entries = p->cq_entries; size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset); if (size == SIZE_MAX) return -EOVERFLOW; rings = io_mem_alloc(size); if (!rings) return -ENOMEM; ctx->rings = rings; ctx->sq_array = (u32 *)((char *)rings + sq_array_offset); rings->sq_ring_mask = p->sq_entries - 1; rings->cq_ring_mask = p->cq_entries - 1; rings->sq_ring_entries = p->sq_entries; rings->cq_ring_entries = p->cq_entries; size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); if (size == SIZE_MAX) { io_mem_free(ctx->rings); ctx->rings = NULL; return -EOVERFLOW; } ctx->sq_sqes = io_mem_alloc(size); if (!ctx->sq_sqes) { io_mem_free(ctx->rings); ctx->rings = NULL; return -ENOMEM; } return 0; } static int io_uring_install_fd(struct io_ring_ctx *ctx, struct file *file) { int ret, fd; fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC); if (fd < 0) return fd; ret = io_uring_add_tctx_node(ctx); if (ret) { put_unused_fd(fd); return ret; } fd_install(fd, file); return fd; } /* * Allocate an anonymous fd, this is what constitutes the application * visible backing of an io_uring instance. The application mmaps this * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled, * we have to tie this fd to a socket for file garbage collection purposes. */ static struct file *io_uring_get_file(struct io_ring_ctx *ctx) { struct file *file; #if defined(CONFIG_UNIX) int ret; ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, &ctx->ring_sock); if (ret) return ERR_PTR(ret); #endif file = anon_inode_getfile_secure("[io_uring]", &io_uring_fops, ctx, O_RDWR | O_CLOEXEC, NULL); #if defined(CONFIG_UNIX) if (IS_ERR(file)) { sock_release(ctx->ring_sock); ctx->ring_sock = NULL; } else { ctx->ring_sock->file = file; } #endif return file; } static __cold int io_uring_create(unsigned entries, struct io_uring_params *p, struct io_uring_params __user *params) { struct io_ring_ctx *ctx; struct file *file; int ret; if (!entries) return -EINVAL; if (entries > IORING_MAX_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; entries = IORING_MAX_ENTRIES; } /* * Use twice as many entries for the CQ ring. It's possible for the * application to drive a higher depth than the size of the SQ ring, * since the sqes are only used at submission time. This allows for * some flexibility in overcommitting a bit. If the application has * set IORING_SETUP_CQSIZE, it will have passed in the desired number * of CQ ring entries manually. */ p->sq_entries = roundup_pow_of_two(entries); if (p->flags & IORING_SETUP_CQSIZE) { /* * If IORING_SETUP_CQSIZE is set, we do the same roundup * to a power-of-two, if it isn't already. We do NOT impose * any cq vs sq ring sizing. */ if (!p->cq_entries) return -EINVAL; if (p->cq_entries > IORING_MAX_CQ_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; p->cq_entries = IORING_MAX_CQ_ENTRIES; } p->cq_entries = roundup_pow_of_two(p->cq_entries); if (p->cq_entries < p->sq_entries) return -EINVAL; } else { p->cq_entries = 2 * p->sq_entries; } ctx = io_ring_ctx_alloc(p); if (!ctx) return -ENOMEM; ctx->compat = in_compat_syscall(); if (!capable(CAP_IPC_LOCK)) ctx->user = get_uid(current_user()); /* * This is just grabbed for accounting purposes. When a process exits, * the mm is exited and dropped before the files, hence we need to hang * on to this mm purely for the purposes of being able to unaccount * memory (locked/pinned vm). It's not used for anything else. */ mmgrab(current->mm); ctx->mm_account = current->mm; ret = io_allocate_scq_urings(ctx, p); if (ret) goto err; ret = io_sq_offload_create(ctx, p); if (ret) goto err; /* always set a rsrc node */ ret = io_rsrc_node_switch_start(ctx); if (ret) goto err; io_rsrc_node_switch(ctx, NULL); memset(&p->sq_off, 0, sizeof(p->sq_off)); p->sq_off.head = offsetof(struct io_rings, sq.head); p->sq_off.tail = offsetof(struct io_rings, sq.tail); p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask); p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries); p->sq_off.flags = offsetof(struct io_rings, sq_flags); p->sq_off.dropped = offsetof(struct io_rings, sq_dropped); p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings; memset(&p->cq_off, 0, sizeof(p->cq_off)); p->cq_off.head = offsetof(struct io_rings, cq.head); p->cq_off.tail = offsetof(struct io_rings, cq.tail); p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask); p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries); p->cq_off.overflow = offsetof(struct io_rings, cq_overflow); p->cq_off.cqes = offsetof(struct io_rings, cqes); p->cq_off.flags = offsetof(struct io_rings, cq_flags); p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS | IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL | IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED | IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS | IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP | IORING_FEAT_LINKED_FILE; if (copy_to_user(params, p, sizeof(*p))) { ret = -EFAULT; goto err; } file = io_uring_get_file(ctx); if (IS_ERR(file)) { ret = PTR_ERR(file); goto err; } /* * Install ring fd as the very last thing, so we don't risk someone * having closed it before we finish setup */ ret = io_uring_install_fd(ctx, file); if (ret < 0) { /* fput will clean it up */ fput(file); return ret; } trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); return ret; err: io_ring_ctx_wait_and_kill(ctx); return ret; } /* * Sets up an aio uring context, and returns the fd. Applications asks for a * ring size, we return the actual sq/cq ring sizes (among other things) in the * params structure passed in. */ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) { struct io_uring_params p; int i; if (copy_from_user(&p, params, sizeof(p))) return -EFAULT; for (i = 0; i < ARRAY_SIZE(p.resv); i++) { if (p.resv[i]) return -EINVAL; } if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE | IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ | IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL)) return -EINVAL; return io_uring_create(entries, &p, params); } SYSCALL_DEFINE2(io_uring_setup, u32, entries, struct io_uring_params __user *, params) { return io_uring_setup(entries, params); } static __cold int io_probe(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct io_uring_probe *p; size_t size; int i, ret; size = struct_size(p, ops, nr_args); if (size == SIZE_MAX) return -EOVERFLOW; p = kzalloc(size, GFP_KERNEL); if (!p) return -ENOMEM; ret = -EFAULT; if (copy_from_user(p, arg, size)) goto out; ret = -EINVAL; if (memchr_inv(p, 0, size)) goto out; p->last_op = IORING_OP_LAST - 1; if (nr_args > IORING_OP_LAST) nr_args = IORING_OP_LAST; for (i = 0; i < nr_args; i++) { p->ops[i].op = i; if (!io_op_defs[i].not_supported) p->ops[i].flags = IO_URING_OP_SUPPORTED; } p->ops_len = i; ret = 0; if (copy_to_user(arg, p, size)) ret = -EFAULT; out: kfree(p); return ret; } static int io_register_personality(struct io_ring_ctx *ctx) { const struct cred *creds; u32 id; int ret; creds = get_current_cred(); ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds, XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL); if (ret < 0) { put_cred(creds); return ret; } return id; } static __cold int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg, unsigned int nr_args) { struct io_uring_restriction *res; size_t size; int i, ret; /* Restrictions allowed only if rings started disabled */ if (!(ctx->flags & IORING_SETUP_R_DISABLED)) return -EBADFD; /* We allow only a single restrictions registration */ if (ctx->restrictions.registered) return -EBUSY; if (!arg || nr_args > IORING_MAX_RESTRICTIONS) return -EINVAL; size = array_size(nr_args, sizeof(*res)); if (size == SIZE_MAX) return -EOVERFLOW; res = memdup_user(arg, size); if (IS_ERR(res)) return PTR_ERR(res); ret = 0; for (i = 0; i < nr_args; i++) { switch (res[i].opcode) { case IORING_RESTRICTION_REGISTER_OP: if (res[i].register_op >= IORING_REGISTER_LAST) { ret = -EINVAL; goto out; } __set_bit(res[i].register_op, ctx->restrictions.register_op); break; case IORING_RESTRICTION_SQE_OP: if (res[i].sqe_op >= IORING_OP_LAST) { ret = -EINVAL; goto out; } __set_bit(res[i].sqe_op, ctx->restrictions.sqe_op); break; case IORING_RESTRICTION_SQE_FLAGS_ALLOWED: ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags; break; case IORING_RESTRICTION_SQE_FLAGS_REQUIRED: ctx->restrictions.sqe_flags_required = res[i].sqe_flags; break; default: ret = -EINVAL; goto out; } } out: /* Reset all restrictions if an error happened */ if (ret != 0) memset(&ctx->restrictions, 0, sizeof(ctx->restrictions)); else ctx->restrictions.registered = true; kfree(res); return ret; } static int io_register_enable_rings(struct io_ring_ctx *ctx) { if (!(ctx->flags & IORING_SETUP_R_DISABLED)) return -EBADFD; if (ctx->restrictions.registered) ctx->restricted = 1; ctx->flags &= ~IORING_SETUP_R_DISABLED; if (ctx->sq_data && wq_has_sleeper(&ctx->sq_data->wait)) wake_up(&ctx->sq_data->wait); return 0; } static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type, struct io_uring_rsrc_update2 *up, unsigned nr_args) { __u32 tmp; int err; if (up->resv) return -EINVAL; if (check_add_overflow(up->offset, nr_args, &tmp)) return -EOVERFLOW; err = io_rsrc_node_switch_start(ctx); if (err) return err; switch (type) { case IORING_RSRC_FILE: return __io_sqe_files_update(ctx, up, nr_args); case IORING_RSRC_BUFFER: return __io_sqe_buffers_update(ctx, up, nr_args); } return -EINVAL; } static int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct io_uring_rsrc_update2 up; if (!nr_args) return -EINVAL; memset(&up, 0, sizeof(up)); if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update))) return -EFAULT; return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args); } static int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, unsigned size, unsigned type) { struct io_uring_rsrc_update2 up; if (size != sizeof(up)) return -EINVAL; if (copy_from_user(&up, arg, sizeof(up))) return -EFAULT; if (!up.nr || up.resv) return -EINVAL; return __io_register_rsrc_update(ctx, type, &up, up.nr); } static __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, unsigned int size, unsigned int type) { struct io_uring_rsrc_register rr; /* keep it extendible */ if (size != sizeof(rr)) return -EINVAL; memset(&rr, 0, sizeof(rr)); if (copy_from_user(&rr, arg, size)) return -EFAULT; if (!rr.nr || rr.resv || rr.resv2) return -EINVAL; switch (type) { case IORING_RSRC_FILE: return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data), rr.nr, u64_to_user_ptr(rr.tags)); case IORING_RSRC_BUFFER: return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data), rr.nr, u64_to_user_ptr(rr.tags)); } return -EINVAL; } static __cold int io_register_iowq_aff(struct io_ring_ctx *ctx, void __user *arg, unsigned len) { struct io_uring_task *tctx = current->io_uring; cpumask_var_t new_mask; int ret; if (!tctx || !tctx->io_wq) return -EINVAL; if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) return -ENOMEM; cpumask_clear(new_mask); if (len > cpumask_size()) len = cpumask_size(); if (in_compat_syscall()) { ret = compat_get_bitmap(cpumask_bits(new_mask), (const compat_ulong_t __user *)arg, len * 8 /* CHAR_BIT */); } else { ret = copy_from_user(new_mask, arg, len); } if (ret) { free_cpumask_var(new_mask); return -EFAULT; } ret = io_wq_cpu_affinity(tctx->io_wq, new_mask); free_cpumask_var(new_mask); return ret; } static __cold int io_unregister_iowq_aff(struct io_ring_ctx *ctx) { struct io_uring_task *tctx = current->io_uring; if (!tctx || !tctx->io_wq) return -EINVAL; return io_wq_cpu_affinity(tctx->io_wq, NULL); } static __cold int io_register_iowq_max_workers(struct io_ring_ctx *ctx, void __user *arg) __must_hold(&ctx->uring_lock) { struct io_tctx_node *node; struct io_uring_task *tctx = NULL; struct io_sq_data *sqd = NULL; __u32 new_count[2]; int i, ret; if (copy_from_user(new_count, arg, sizeof(new_count))) return -EFAULT; for (i = 0; i < ARRAY_SIZE(new_count); i++) if (new_count[i] > INT_MAX) return -EINVAL; if (ctx->flags & IORING_SETUP_SQPOLL) { sqd = ctx->sq_data; if (sqd) { /* * Observe the correct sqd->lock -> ctx->uring_lock * ordering. Fine to drop uring_lock here, we hold * a ref to the ctx. */ refcount_inc(&sqd->refs); mutex_unlock(&ctx->uring_lock); mutex_lock(&sqd->lock); mutex_lock(&ctx->uring_lock); if (sqd->thread) tctx = sqd->thread->io_uring; } } else { tctx = current->io_uring; } BUILD_BUG_ON(sizeof(new_count) != sizeof(ctx->iowq_limits)); for (i = 0; i < ARRAY_SIZE(new_count); i++) if (new_count[i]) ctx->iowq_limits[i] = new_count[i]; ctx->iowq_limits_set = true; if (tctx && tctx->io_wq) { ret = io_wq_max_workers(tctx->io_wq, new_count); if (ret) goto err; } else { memset(new_count, 0, sizeof(new_count)); } if (sqd) { mutex_unlock(&sqd->lock); io_put_sq_data(sqd); } if (copy_to_user(arg, new_count, sizeof(new_count))) return -EFAULT; /* that's it for SQPOLL, only the SQPOLL task creates requests */ if (sqd) return 0; /* now propagate the restriction to all registered users */ list_for_each_entry(node, &ctx->tctx_list, ctx_node) { struct io_uring_task *tctx = node->task->io_uring; if (WARN_ON_ONCE(!tctx->io_wq)) continue; for (i = 0; i < ARRAY_SIZE(new_count); i++) new_count[i] = ctx->iowq_limits[i]; /* ignore errors, it always returns zero anyway */ (void)io_wq_max_workers(tctx->io_wq, new_count); } return 0; err: if (sqd) { mutex_unlock(&sqd->lock); io_put_sq_data(sqd); } return ret; } static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, void __user *arg, unsigned nr_args) __releases(ctx->uring_lock) __acquires(ctx->uring_lock) { int ret; /* * We're inside the ring mutex, if the ref is already dying, then * someone else killed the ctx or is already going through * io_uring_register(). */ if (percpu_ref_is_dying(&ctx->refs)) return -ENXIO; if (ctx->restricted) { if (opcode >= IORING_REGISTER_LAST) return -EINVAL; opcode = array_index_nospec(opcode, IORING_REGISTER_LAST); if (!test_bit(opcode, ctx->restrictions.register_op)) return -EACCES; } switch (opcode) { case IORING_REGISTER_BUFFERS: ret = io_sqe_buffers_register(ctx, arg, nr_args, NULL); break; case IORING_UNREGISTER_BUFFERS: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_buffers_unregister(ctx); break; case IORING_REGISTER_FILES: ret = io_sqe_files_register(ctx, arg, nr_args, NULL); break; case IORING_UNREGISTER_FILES: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_files_unregister(ctx); break; case IORING_REGISTER_FILES_UPDATE: ret = io_register_files_update(ctx, arg, nr_args); break; case IORING_REGISTER_EVENTFD: ret = -EINVAL; if (nr_args != 1) break; ret = io_eventfd_register(ctx, arg, 0); break; case IORING_REGISTER_EVENTFD_ASYNC: ret = -EINVAL; if (nr_args != 1) break; ret = io_eventfd_register(ctx, arg, 1); break; case IORING_UNREGISTER_EVENTFD: ret = -EINVAL; if (arg || nr_args) break; ret = io_eventfd_unregister(ctx); break; case IORING_REGISTER_PROBE: ret = -EINVAL; if (!arg || nr_args > 256) break; ret = io_probe(ctx, arg, nr_args); break; case IORING_REGISTER_PERSONALITY: ret = -EINVAL; if (arg || nr_args) break; ret = io_register_personality(ctx); break; case IORING_UNREGISTER_PERSONALITY: ret = -EINVAL; if (arg) break; ret = io_unregister_personality(ctx, nr_args); break; case IORING_REGISTER_ENABLE_RINGS: ret = -EINVAL; if (arg || nr_args) break; ret = io_register_enable_rings(ctx); break; case IORING_REGISTER_RESTRICTIONS: ret = io_register_restrictions(ctx, arg, nr_args); break; case IORING_REGISTER_FILES2: ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_FILE); break; case IORING_REGISTER_FILES_UPDATE2: ret = io_register_rsrc_update(ctx, arg, nr_args, IORING_RSRC_FILE); break; case IORING_REGISTER_BUFFERS2: ret = io_register_rsrc(ctx, arg, nr_args, IORING_RSRC_BUFFER); break; case IORING_REGISTER_BUFFERS_UPDATE: ret = io_register_rsrc_update(ctx, arg, nr_args, IORING_RSRC_BUFFER); break; case IORING_REGISTER_IOWQ_AFF: ret = -EINVAL; if (!arg || !nr_args) break; ret = io_register_iowq_aff(ctx, arg, nr_args); break; case IORING_UNREGISTER_IOWQ_AFF: ret = -EINVAL; if (arg || nr_args) break; ret = io_unregister_iowq_aff(ctx); break; case IORING_REGISTER_IOWQ_MAX_WORKERS: ret = -EINVAL; if (!arg || nr_args != 2) break; ret = io_register_iowq_max_workers(ctx, arg); break; case IORING_REGISTER_RING_FDS: ret = io_ringfd_register(ctx, arg, nr_args); break; case IORING_UNREGISTER_RING_FDS: ret = io_ringfd_unregister(ctx, arg, nr_args); break; default: ret = -EINVAL; break; } return ret; } SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, void __user *, arg, unsigned int, nr_args) { struct io_ring_ctx *ctx; long ret = -EBADF; struct fd f; f = fdget(fd); if (!f.file) return -EBADF; ret = -EOPNOTSUPP; if (f.file->f_op != &io_uring_fops) goto out_fput; ctx = f.file->private_data; io_run_task_work(); mutex_lock(&ctx->uring_lock); ret = __io_uring_register(ctx, opcode, arg, nr_args); mutex_unlock(&ctx->uring_lock); trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ret); out_fput: fdput(f); return ret; } static int __init io_uring_init(void) { #define __BUILD_BUG_VERIFY_ELEMENT(stype, eoffset, etype, ename) do { \ BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \ BUILD_BUG_ON(sizeof(etype) != sizeof_field(stype, ename)); \ } while (0) #define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \ __BUILD_BUG_VERIFY_ELEMENT(struct io_uring_sqe, eoffset, etype, ename) BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64); BUILD_BUG_SQE_ELEM(0, __u8, opcode); BUILD_BUG_SQE_ELEM(1, __u8, flags); BUILD_BUG_SQE_ELEM(2, __u16, ioprio); BUILD_BUG_SQE_ELEM(4, __s32, fd); BUILD_BUG_SQE_ELEM(8, __u64, off); BUILD_BUG_SQE_ELEM(8, __u64, addr2); BUILD_BUG_SQE_ELEM(16, __u64, addr); BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in); BUILD_BUG_SQE_ELEM(24, __u32, len); BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags); BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags); BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events); BUILD_BUG_SQE_ELEM(28, __u32, poll32_events); BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags); BUILD_BUG_SQE_ELEM(28, __u32, msg_flags); BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags); BUILD_BUG_SQE_ELEM(28, __u32, accept_flags); BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags); BUILD_BUG_SQE_ELEM(28, __u32, open_flags); BUILD_BUG_SQE_ELEM(28, __u32, statx_flags); BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice); BUILD_BUG_SQE_ELEM(28, __u32, splice_flags); BUILD_BUG_SQE_ELEM(32, __u64, user_data); BUILD_BUG_SQE_ELEM(40, __u16, buf_index); BUILD_BUG_SQE_ELEM(40, __u16, buf_group); BUILD_BUG_SQE_ELEM(42, __u16, personality); BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in); BUILD_BUG_SQE_ELEM(44, __u32, file_index); BUILD_BUG_ON(sizeof(struct io_uring_files_update) != sizeof(struct io_uring_rsrc_update)); BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) > sizeof(struct io_uring_rsrc_update2)); /* ->buf_index is u16 */ BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16)); /* should fit into one byte */ BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8)); BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8)); BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS); BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST); BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof(int)); req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT); return 0; }; __initcall(io_uring_init);