// SPDX-License-Identifier: GPL-2.0 /* * gendisk handling * * Portions Copyright (C) 2020 Christoph Hellwig */ #include <linux/module.h> #include <linux/ctype.h> #include <linux/fs.h> #include <linux/kdev_t.h> #include <linux/kernel.h> #include <linux/blkdev.h> #include <linux/backing-dev.h> #include <linux/init.h> #include <linux/spinlock.h> #include <linux/proc_fs.h> #include <linux/seq_file.h> #include <linux/slab.h> #include <linux/kmod.h> #include <linux/major.h> #include <linux/mutex.h> #include <linux/idr.h> #include <linux/log2.h> #include <linux/pm_runtime.h> #include <linux/badblocks.h> #include <linux/part_stat.h> #include "blk-throttle.h" #include "blk.h" #include "blk-mq-sched.h" #include "blk-rq-qos.h" #include "blk-cgroup.h" static struct kobject *block_depr; /* * Unique, monotonically increasing sequential number associated with block * devices instances (i.e. incremented each time a device is attached). * Associating uevents with block devices in userspace is difficult and racy: * the uevent netlink socket is lossy, and on slow and overloaded systems has * a very high latency. * Block devices do not have exclusive owners in userspace, any process can set * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0 * can be reused again and again). * A userspace process setting up a block device and watching for its events * cannot thus reliably tell whether an event relates to the device it just set * up or another earlier instance with the same name. * This sequential number allows userspace processes to solve this problem, and * uniquely associate an uevent to the lifetime to a device. */ static atomic64_t diskseq; /* for extended dynamic devt allocation, currently only one major is used */ #define NR_EXT_DEVT (1 << MINORBITS) static DEFINE_IDA(ext_devt_ida); void set_capacity(struct gendisk *disk, sector_t sectors) { bdev_set_nr_sectors(disk->part0, sectors); } EXPORT_SYMBOL(set_capacity); /* * Set disk capacity and notify if the size is not currently zero and will not * be set to zero. Returns true if a uevent was sent, otherwise false. */ bool set_capacity_and_notify(struct gendisk *disk, sector_t size) { sector_t capacity = get_capacity(disk); char *envp[] = { "RESIZE=1", NULL }; set_capacity(disk, size); /* * Only print a message and send a uevent if the gendisk is user visible * and alive. This avoids spamming the log and udev when setting the * initial capacity during probing. */ if (size == capacity || !disk_live(disk) || (disk->flags & GENHD_FL_HIDDEN)) return false; pr_info("%s: detected capacity change from %lld to %lld\n", disk->disk_name, capacity, size); /* * Historically we did not send a uevent for changes to/from an empty * device. */ if (!capacity || !size) return false; kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp); return true; } EXPORT_SYMBOL_GPL(set_capacity_and_notify); static void part_stat_read_all(struct block_device *part, struct disk_stats *stat) { int cpu; memset(stat, 0, sizeof(struct disk_stats)); for_each_possible_cpu(cpu) { struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu); int group; for (group = 0; group < NR_STAT_GROUPS; group++) { stat->nsecs[group] += ptr->nsecs[group]; stat->sectors[group] += ptr->sectors[group]; stat->ios[group] += ptr->ios[group]; stat->merges[group] += ptr->merges[group]; } stat->io_ticks += ptr->io_ticks; } } static unsigned int part_in_flight(struct block_device *part) { unsigned int inflight = 0; int cpu; for_each_possible_cpu(cpu) { inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) + part_stat_local_read_cpu(part, in_flight[1], cpu); } if ((int)inflight < 0) inflight = 0; return inflight; } static void part_in_flight_rw(struct block_device *part, unsigned int inflight[2]) { int cpu; inflight[0] = 0; inflight[1] = 0; for_each_possible_cpu(cpu) { inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu); inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu); } if ((int)inflight[0] < 0) inflight[0] = 0; if ((int)inflight[1] < 0) inflight[1] = 0; } /* * Can be deleted altogether. Later. * */ #define BLKDEV_MAJOR_HASH_SIZE 255 static struct blk_major_name { struct blk_major_name *next; int major; char name[16]; #ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD void (*probe)(dev_t devt); #endif } *major_names[BLKDEV_MAJOR_HASH_SIZE]; static DEFINE_MUTEX(major_names_lock); static DEFINE_SPINLOCK(major_names_spinlock); /* index in the above - for now: assume no multimajor ranges */ static inline int major_to_index(unsigned major) { return major % BLKDEV_MAJOR_HASH_SIZE; } #ifdef CONFIG_PROC_FS void blkdev_show(struct seq_file *seqf, off_t offset) { struct blk_major_name *dp; spin_lock(&major_names_spinlock); for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next) if (dp->major == offset) seq_printf(seqf, "%3d %s\n", dp->major, dp->name); spin_unlock(&major_names_spinlock); } #endif /* CONFIG_PROC_FS */ /** * __register_blkdev - register a new block device * * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If * @major = 0, try to allocate any unused major number. * @name: the name of the new block device as a zero terminated string * @probe: pre-devtmpfs / pre-udev callback used to create disks when their * pre-created device node is accessed. When a probe call uses * add_disk() and it fails the driver must cleanup resources. This * interface may soon be removed. * * The @name must be unique within the system. * * The return value depends on the @major input parameter: * * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1] * then the function returns zero on success, or a negative error code * - if any unused major number was requested with @major = 0 parameter * then the return value is the allocated major number in range * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise * * See Documentation/admin-guide/devices.txt for the list of allocated * major numbers. * * Use register_blkdev instead for any new code. */ int __register_blkdev(unsigned int major, const char *name, void (*probe)(dev_t devt)) { struct blk_major_name **n, *p; int index, ret = 0; mutex_lock(&major_names_lock); /* temporary */ if (major == 0) { for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) { if (major_names[index] == NULL) break; } if (index == 0) { printk("%s: failed to get major for %s\n", __func__, name); ret = -EBUSY; goto out; } major = index; ret = major; } if (major >= BLKDEV_MAJOR_MAX) { pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n", __func__, major, BLKDEV_MAJOR_MAX-1, name); ret = -EINVAL; goto out; } p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL); if (p == NULL) { ret = -ENOMEM; goto out; } p->major = major; #ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD p->probe = probe; #endif strlcpy(p->name, name, sizeof(p->name)); p->next = NULL; index = major_to_index(major); spin_lock(&major_names_spinlock); for (n = &major_names[index]; *n; n = &(*n)->next) { if ((*n)->major == major) break; } if (!*n) *n = p; else ret = -EBUSY; spin_unlock(&major_names_spinlock); if (ret < 0) { printk("register_blkdev: cannot get major %u for %s\n", major, name); kfree(p); } out: mutex_unlock(&major_names_lock); return ret; } EXPORT_SYMBOL(__register_blkdev); void unregister_blkdev(unsigned int major, const char *name) { struct blk_major_name **n; struct blk_major_name *p = NULL; int index = major_to_index(major); mutex_lock(&major_names_lock); spin_lock(&major_names_spinlock); for (n = &major_names[index]; *n; n = &(*n)->next) if ((*n)->major == major) break; if (!*n || strcmp((*n)->name, name)) { WARN_ON(1); } else { p = *n; *n = p->next; } spin_unlock(&major_names_spinlock); mutex_unlock(&major_names_lock); kfree(p); } EXPORT_SYMBOL(unregister_blkdev); int blk_alloc_ext_minor(void) { int idx; idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL); if (idx == -ENOSPC) return -EBUSY; return idx; } void blk_free_ext_minor(unsigned int minor) { ida_free(&ext_devt_ida, minor); } static char *bdevt_str(dev_t devt, char *buf) { if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) { char tbuf[BDEVT_SIZE]; snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt)); snprintf(buf, BDEVT_SIZE, "%-9s", tbuf); } else snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt)); return buf; } void disk_uevent(struct gendisk *disk, enum kobject_action action) { struct block_device *part; unsigned long idx; rcu_read_lock(); xa_for_each(&disk->part_tbl, idx, part) { if (bdev_is_partition(part) && !bdev_nr_sectors(part)) continue; if (!kobject_get_unless_zero(&part->bd_device.kobj)) continue; rcu_read_unlock(); kobject_uevent(bdev_kobj(part), action); put_device(&part->bd_device); rcu_read_lock(); } rcu_read_unlock(); } EXPORT_SYMBOL_GPL(disk_uevent); int disk_scan_partitions(struct gendisk *disk, fmode_t mode) { struct block_device *bdev; int ret = 0; if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN)) return -EINVAL; if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) return -EINVAL; if (disk->open_partitions) return -EBUSY; /* * If the device is opened exclusively by current thread already, it's * safe to scan partitons, otherwise, use bd_prepare_to_claim() to * synchronize with other exclusive openers and other partition * scanners. */ if (!(mode & FMODE_EXCL)) { ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions); if (ret) return ret; } set_bit(GD_NEED_PART_SCAN, &disk->state); bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL); if (IS_ERR(bdev)) ret = PTR_ERR(bdev); else blkdev_put(bdev, mode & ~FMODE_EXCL); /* * If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set, * and this will cause that re-assemble partitioned raid device will * creat partition for underlying disk. */ clear_bit(GD_NEED_PART_SCAN, &disk->state); if (!(mode & FMODE_EXCL)) bd_abort_claiming(disk->part0, disk_scan_partitions); return ret; } /** * device_add_disk - add disk information to kernel list * @parent: parent device for the disk * @disk: per-device partitioning information * @groups: Additional per-device sysfs groups * * This function registers the partitioning information in @disk * with the kernel. */ int __must_check device_add_disk(struct device *parent, struct gendisk *disk, const struct attribute_group **groups) { struct device *ddev = disk_to_dev(disk); int ret; /* Only makes sense for bio-based to set ->poll_bio */ if (queue_is_mq(disk->queue) && disk->fops->poll_bio) return -EINVAL; /* * The disk queue should now be all set with enough information about * the device for the elevator code to pick an adequate default * elevator if one is needed, that is, for devices requesting queue * registration. */ elevator_init_mq(disk->queue); /* Mark bdev as having a submit_bio, if needed */ disk->part0->bd_has_submit_bio = disk->fops->submit_bio != NULL; /* * If the driver provides an explicit major number it also must provide * the number of minors numbers supported, and those will be used to * setup the gendisk. * Otherwise just allocate the device numbers for both the whole device * and all partitions from the extended dev_t space. */ ret = -EINVAL; if (disk->major) { if (WARN_ON(!disk->minors)) goto out_exit_elevator; if (disk->minors > DISK_MAX_PARTS) { pr_err("block: can't allocate more than %d partitions\n", DISK_MAX_PARTS); disk->minors = DISK_MAX_PARTS; } if (disk->first_minor + disk->minors > MINORMASK + 1) goto out_exit_elevator; } else { if (WARN_ON(disk->minors)) goto out_exit_elevator; ret = blk_alloc_ext_minor(); if (ret < 0) goto out_exit_elevator; disk->major = BLOCK_EXT_MAJOR; disk->first_minor = ret; } /* delay uevents, until we scanned partition table */ dev_set_uevent_suppress(ddev, 1); ddev->parent = parent; ddev->groups = groups; dev_set_name(ddev, "%s", disk->disk_name); if (!(disk->flags & GENHD_FL_HIDDEN)) ddev->devt = MKDEV(disk->major, disk->first_minor); ret = device_add(ddev); if (ret) goto out_free_ext_minor; ret = disk_alloc_events(disk); if (ret) goto out_device_del; ret = sysfs_create_link(block_depr, &ddev->kobj, kobject_name(&ddev->kobj)); if (ret) goto out_device_del; /* * avoid probable deadlock caused by allocating memory with * GFP_KERNEL in runtime_resume callback of its all ancestor * devices */ pm_runtime_set_memalloc_noio(ddev, true); disk->part0->bd_holder_dir = kobject_create_and_add("holders", &ddev->kobj); if (!disk->part0->bd_holder_dir) { ret = -ENOMEM; goto out_del_block_link; } disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj); if (!disk->slave_dir) { ret = -ENOMEM; goto out_put_holder_dir; } ret = blk_register_queue(disk); if (ret) goto out_put_slave_dir; if (!(disk->flags & GENHD_FL_HIDDEN)) { ret = bdi_register(disk->bdi, "%u:%u", disk->major, disk->first_minor); if (ret) goto out_unregister_queue; bdi_set_owner(disk->bdi, ddev); ret = sysfs_create_link(&ddev->kobj, &disk->bdi->dev->kobj, "bdi"); if (ret) goto out_unregister_bdi; /* Make sure the first partition scan will be proceed */ if (get_capacity(disk) && !(disk->flags & GENHD_FL_NO_PART) && !test_bit(GD_SUPPRESS_PART_SCAN, &disk->state)) set_bit(GD_NEED_PART_SCAN, &disk->state); bdev_add(disk->part0, ddev->devt); if (get_capacity(disk)) disk_scan_partitions(disk, FMODE_READ); /* * Announce the disk and partitions after all partitions are * created. (for hidden disks uevents remain suppressed forever) */ dev_set_uevent_suppress(ddev, 0); disk_uevent(disk, KOBJ_ADD); } else { /* * Even if the block_device for a hidden gendisk is not * registered, it needs to have a valid bd_dev so that the * freeing of the dynamic major works. */ disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor); } disk_update_readahead(disk); disk_add_events(disk); set_bit(GD_ADDED, &disk->state); return 0; out_unregister_bdi: if (!(disk->flags & GENHD_FL_HIDDEN)) bdi_unregister(disk->bdi); out_unregister_queue: blk_unregister_queue(disk); rq_qos_exit(disk->queue); out_put_slave_dir: kobject_put(disk->slave_dir); disk->slave_dir = NULL; out_put_holder_dir: kobject_put(disk->part0->bd_holder_dir); out_del_block_link: sysfs_remove_link(block_depr, dev_name(ddev)); out_device_del: device_del(ddev); out_free_ext_minor: if (disk->major == BLOCK_EXT_MAJOR) blk_free_ext_minor(disk->first_minor); out_exit_elevator: if (disk->queue->elevator) elevator_exit(disk->queue); return ret; } EXPORT_SYMBOL(device_add_disk); /** * blk_mark_disk_dead - mark a disk as dead * @disk: disk to mark as dead * * Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O * to this disk. */ void blk_mark_disk_dead(struct gendisk *disk) { set_bit(GD_DEAD, &disk->state); blk_queue_start_drain(disk->queue); /* * Stop buffered writers from dirtying pages that can't be written out. */ set_capacity_and_notify(disk, 0); } EXPORT_SYMBOL_GPL(blk_mark_disk_dead); /** * del_gendisk - remove the gendisk * @disk: the struct gendisk to remove * * Removes the gendisk and all its associated resources. This deletes the * partitions associated with the gendisk, and unregisters the associated * request_queue. * * This is the counter to the respective __device_add_disk() call. * * The final removal of the struct gendisk happens when its refcount reaches 0 * with put_disk(), which should be called after del_gendisk(), if * __device_add_disk() was used. * * Drivers exist which depend on the release of the gendisk to be synchronous, * it should not be deferred. * * Context: can sleep */ void del_gendisk(struct gendisk *disk) { struct request_queue *q = disk->queue; might_sleep(); if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN))) return; disk_del_events(disk); mutex_lock(&disk->open_mutex); remove_inode_hash(disk->part0->bd_inode); blk_drop_partitions(disk); mutex_unlock(&disk->open_mutex); fsync_bdev(disk->part0); __invalidate_device(disk->part0, true); /* * Fail any new I/O. */ set_bit(GD_DEAD, &disk->state); if (test_bit(GD_OWNS_QUEUE, &disk->state)) blk_queue_flag_set(QUEUE_FLAG_DYING, q); set_capacity(disk, 0); /* * Prevent new I/O from crossing bio_queue_enter(). */ blk_queue_start_drain(q); if (!(disk->flags & GENHD_FL_HIDDEN)) { sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi"); /* * Unregister bdi before releasing device numbers (as they can * get reused and we'd get clashes in sysfs). */ bdi_unregister(disk->bdi); } blk_unregister_queue(disk); kobject_put(disk->part0->bd_holder_dir); kobject_put(disk->slave_dir); disk->slave_dir = NULL; part_stat_set_all(disk->part0, 0); disk->part0->bd_stamp = 0; sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); device_del(disk_to_dev(disk)); blk_mq_freeze_queue_wait(q); blk_throtl_cancel_bios(disk); blk_sync_queue(q); blk_flush_integrity(); if (queue_is_mq(q)) blk_mq_cancel_work_sync(q); blk_mq_quiesce_queue(q); if (q->elevator) { mutex_lock(&q->sysfs_lock); elevator_exit(q); mutex_unlock(&q->sysfs_lock); } rq_qos_exit(q); blk_mq_unquiesce_queue(q); /* * If the disk does not own the queue, allow using passthrough requests * again. Else leave the queue frozen to fail all I/O. */ if (!test_bit(GD_OWNS_QUEUE, &disk->state)) { blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q); __blk_mq_unfreeze_queue(q, true); } else { if (queue_is_mq(q)) blk_mq_exit_queue(q); } } EXPORT_SYMBOL(del_gendisk); /** * invalidate_disk - invalidate the disk * @disk: the struct gendisk to invalidate * * A helper to invalidates the disk. It will clean the disk's associated * buffer/page caches and reset its internal states so that the disk * can be reused by the drivers. * * Context: can sleep */ void invalidate_disk(struct gendisk *disk) { struct block_device *bdev = disk->part0; invalidate_bdev(bdev); bdev->bd_inode->i_mapping->wb_err = 0; set_capacity(disk, 0); } EXPORT_SYMBOL(invalidate_disk); /* sysfs access to bad-blocks list. */ static ssize_t disk_badblocks_show(struct device *dev, struct device_attribute *attr, char *page) { struct gendisk *disk = dev_to_disk(dev); if (!disk->bb) return sprintf(page, "\n"); return badblocks_show(disk->bb, page, 0); } static ssize_t disk_badblocks_store(struct device *dev, struct device_attribute *attr, const char *page, size_t len) { struct gendisk *disk = dev_to_disk(dev); if (!disk->bb) return -ENXIO; return badblocks_store(disk->bb, page, len, 0); } #ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD void blk_request_module(dev_t devt) { unsigned int major = MAJOR(devt); struct blk_major_name **n; mutex_lock(&major_names_lock); for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) { if ((*n)->major == major && (*n)->probe) { (*n)->probe(devt); mutex_unlock(&major_names_lock); return; } } mutex_unlock(&major_names_lock); if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0) /* Make old-style 2.4 aliases work */ request_module("block-major-%d", MAJOR(devt)); } #endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */ /* * print a full list of all partitions - intended for places where the root * filesystem can't be mounted and thus to give the victim some idea of what * went wrong */ void __init printk_all_partitions(void) { struct class_dev_iter iter; struct device *dev; class_dev_iter_init(&iter, &block_class, NULL, &disk_type); while ((dev = class_dev_iter_next(&iter))) { struct gendisk *disk = dev_to_disk(dev); struct block_device *part; char devt_buf[BDEVT_SIZE]; unsigned long idx; /* * Don't show empty devices or things that have been * suppressed */ if (get_capacity(disk) == 0 || (disk->flags & GENHD_FL_HIDDEN)) continue; /* * Note, unlike /proc/partitions, I am showing the numbers in * hex - the same format as the root= option takes. */ rcu_read_lock(); xa_for_each(&disk->part_tbl, idx, part) { if (!bdev_nr_sectors(part)) continue; printk("%s%s %10llu %pg %s", bdev_is_partition(part) ? " " : "", bdevt_str(part->bd_dev, devt_buf), bdev_nr_sectors(part) >> 1, part, part->bd_meta_info ? part->bd_meta_info->uuid : ""); if (bdev_is_partition(part)) printk("\n"); else if (dev->parent && dev->parent->driver) printk(" driver: %s\n", dev->parent->driver->name); else printk(" (driver?)\n"); } rcu_read_unlock(); } class_dev_iter_exit(&iter); } #ifdef CONFIG_PROC_FS /* iterator */ static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos) { loff_t skip = *pos; struct class_dev_iter *iter; struct device *dev; iter = kmalloc(sizeof(*iter), GFP_KERNEL); if (!iter) return ERR_PTR(-ENOMEM); seqf->private = iter; class_dev_iter_init(iter, &block_class, NULL, &disk_type); do { dev = class_dev_iter_next(iter); if (!dev) return NULL; } while (skip--); return dev_to_disk(dev); } static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos) { struct device *dev; (*pos)++; dev = class_dev_iter_next(seqf->private); if (dev) return dev_to_disk(dev); return NULL; } static void disk_seqf_stop(struct seq_file *seqf, void *v) { struct class_dev_iter *iter = seqf->private; /* stop is called even after start failed :-( */ if (iter) { class_dev_iter_exit(iter); kfree(iter); seqf->private = NULL; } } static void *show_partition_start(struct seq_file *seqf, loff_t *pos) { void *p; p = disk_seqf_start(seqf, pos); if (!IS_ERR_OR_NULL(p) && !*pos) seq_puts(seqf, "major minor #blocks name\n\n"); return p; } static int show_partition(struct seq_file *seqf, void *v) { struct gendisk *sgp = v; struct block_device *part; unsigned long idx; if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN)) return 0; rcu_read_lock(); xa_for_each(&sgp->part_tbl, idx, part) { if (!bdev_nr_sectors(part)) continue; seq_printf(seqf, "%4d %7d %10llu %pg\n", MAJOR(part->bd_dev), MINOR(part->bd_dev), bdev_nr_sectors(part) >> 1, part); } rcu_read_unlock(); return 0; } static const struct seq_operations partitions_op = { .start = show_partition_start, .next = disk_seqf_next, .stop = disk_seqf_stop, .show = show_partition }; #endif static int __init genhd_device_init(void) { int error; error = class_register(&block_class); if (unlikely(error)) return error; blk_dev_init(); register_blkdev(BLOCK_EXT_MAJOR, "blkext"); /* create top-level block dir */ block_depr = kobject_create_and_add("block", NULL); return 0; } subsys_initcall(genhd_device_init); static ssize_t disk_range_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", disk->minors); } static ssize_t disk_ext_range_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", (disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS); } static ssize_t disk_removable_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0)); } static ssize_t disk_hidden_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", (disk->flags & GENHD_FL_HIDDEN ? 1 : 0)); } static ssize_t disk_ro_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0); } ssize_t part_size_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev))); } ssize_t part_stat_show(struct device *dev, struct device_attribute *attr, char *buf) { struct block_device *bdev = dev_to_bdev(dev); struct request_queue *q = bdev_get_queue(bdev); struct disk_stats stat; unsigned int inflight; if (queue_is_mq(q)) inflight = blk_mq_in_flight(q, bdev); else inflight = part_in_flight(bdev); if (inflight) { part_stat_lock(); update_io_ticks(bdev, jiffies, true); part_stat_unlock(); } part_stat_read_all(bdev, &stat); return sprintf(buf, "%8lu %8lu %8llu %8u " "%8lu %8lu %8llu %8u " "%8u %8u %8u " "%8lu %8lu %8llu %8u " "%8lu %8u" "\n", stat.ios[STAT_READ], stat.merges[STAT_READ], (unsigned long long)stat.sectors[STAT_READ], (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC), stat.ios[STAT_WRITE], stat.merges[STAT_WRITE], (unsigned long long)stat.sectors[STAT_WRITE], (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC), inflight, jiffies_to_msecs(stat.io_ticks), (unsigned int)div_u64(stat.nsecs[STAT_READ] + stat.nsecs[STAT_WRITE] + stat.nsecs[STAT_DISCARD] + stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC), stat.ios[STAT_DISCARD], stat.merges[STAT_DISCARD], (unsigned long long)stat.sectors[STAT_DISCARD], (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC), stat.ios[STAT_FLUSH], (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC)); } ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr, char *buf) { struct block_device *bdev = dev_to_bdev(dev); struct request_queue *q = bdev_get_queue(bdev); unsigned int inflight[2]; if (queue_is_mq(q)) blk_mq_in_flight_rw(q, bdev, inflight); else part_in_flight_rw(bdev, inflight); return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]); } static ssize_t disk_capability_show(struct device *dev, struct device_attribute *attr, char *buf) { dev_warn_once(dev, "the capability attribute has been deprecated.\n"); return sprintf(buf, "0\n"); } static ssize_t disk_alignment_offset_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0)); } static ssize_t disk_discard_alignment_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0)); } static ssize_t diskseq_show(struct device *dev, struct device_attribute *attr, char *buf) { struct gendisk *disk = dev_to_disk(dev); return sprintf(buf, "%llu\n", disk->diskseq); } static DEVICE_ATTR(range, 0444, disk_range_show, NULL); static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL); static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL); static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL); static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL); static DEVICE_ATTR(size, 0444, part_size_show, NULL); static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL); static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL); static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL); static DEVICE_ATTR(stat, 0444, part_stat_show, NULL); static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL); static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store); static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL); #ifdef CONFIG_FAIL_MAKE_REQUEST ssize_t part_fail_show(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail); } ssize_t part_fail_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { int i; if (count > 0 && sscanf(buf, "%d", &i) > 0) dev_to_bdev(dev)->bd_make_it_fail = i; return count; } static struct device_attribute dev_attr_fail = __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store); #endif /* CONFIG_FAIL_MAKE_REQUEST */ #ifdef CONFIG_FAIL_IO_TIMEOUT static struct device_attribute dev_attr_fail_timeout = __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store); #endif static struct attribute *disk_attrs[] = { &dev_attr_range.attr, &dev_attr_ext_range.attr, &dev_attr_removable.attr, &dev_attr_hidden.attr, &dev_attr_ro.attr, &dev_attr_size.attr, &dev_attr_alignment_offset.attr, &dev_attr_discard_alignment.attr, &dev_attr_capability.attr, &dev_attr_stat.attr, &dev_attr_inflight.attr, &dev_attr_badblocks.attr, &dev_attr_events.attr, &dev_attr_events_async.attr, &dev_attr_events_poll_msecs.attr, &dev_attr_diskseq.attr, #ifdef CONFIG_FAIL_MAKE_REQUEST &dev_attr_fail.attr, #endif #ifdef CONFIG_FAIL_IO_TIMEOUT &dev_attr_fail_timeout.attr, #endif NULL }; static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n) { struct device *dev = container_of(kobj, typeof(*dev), kobj); struct gendisk *disk = dev_to_disk(dev); if (a == &dev_attr_badblocks.attr && !disk->bb) return 0; return a->mode; } static struct attribute_group disk_attr_group = { .attrs = disk_attrs, .is_visible = disk_visible, }; static const struct attribute_group *disk_attr_groups[] = { &disk_attr_group, #ifdef CONFIG_BLK_DEV_IO_TRACE &blk_trace_attr_group, #endif #ifdef CONFIG_BLK_DEV_INTEGRITY &blk_integrity_attr_group, #endif NULL }; /** * disk_release - releases all allocated resources of the gendisk * @dev: the device representing this disk * * This function releases all allocated resources of the gendisk. * * Drivers which used __device_add_disk() have a gendisk with a request_queue * assigned. Since the request_queue sits on top of the gendisk for these * drivers we also call blk_put_queue() for them, and we expect the * request_queue refcount to reach 0 at this point, and so the request_queue * will also be freed prior to the disk. * * Context: can sleep */ static void disk_release(struct device *dev) { struct gendisk *disk = dev_to_disk(dev); might_sleep(); WARN_ON_ONCE(disk_live(disk)); /* * To undo the all initialization from blk_mq_init_allocated_queue in * case of a probe failure where add_disk is never called we have to * call blk_mq_exit_queue here. We can't do this for the more common * teardown case (yet) as the tagset can be gone by the time the disk * is released once it was added. */ if (queue_is_mq(disk->queue) && test_bit(GD_OWNS_QUEUE, &disk->state) && !test_bit(GD_ADDED, &disk->state)) blk_mq_exit_queue(disk->queue); blkcg_exit_disk(disk); bioset_exit(&disk->bio_split); disk_release_events(disk); kfree(disk->random); disk_free_zone_bitmaps(disk); xa_destroy(&disk->part_tbl); disk->queue->disk = NULL; blk_put_queue(disk->queue); if (test_bit(GD_ADDED, &disk->state) && disk->fops->free_disk) disk->fops->free_disk(disk); iput(disk->part0->bd_inode); /* frees the disk */ } static int block_uevent(const struct device *dev, struct kobj_uevent_env *env) { const struct gendisk *disk = dev_to_disk(dev); return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq); } struct class block_class = { .name = "block", .dev_uevent = block_uevent, }; static char *block_devnode(const struct device *dev, umode_t *mode, kuid_t *uid, kgid_t *gid) { struct gendisk *disk = dev_to_disk(dev); if (disk->fops->devnode) return disk->fops->devnode(disk, mode); return NULL; } const struct device_type disk_type = { .name = "disk", .groups = disk_attr_groups, .release = disk_release, .devnode = block_devnode, }; #ifdef CONFIG_PROC_FS /* * aggregate disk stat collector. Uses the same stats that the sysfs * entries do, above, but makes them available through one seq_file. * * The output looks suspiciously like /proc/partitions with a bunch of * extra fields. */ static int diskstats_show(struct seq_file *seqf, void *v) { struct gendisk *gp = v; struct block_device *hd; unsigned int inflight; struct disk_stats stat; unsigned long idx; /* if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next) seq_puts(seqf, "major minor name" " rio rmerge rsect ruse wio wmerge " "wsect wuse running use aveq" "\n\n"); */ rcu_read_lock(); xa_for_each(&gp->part_tbl, idx, hd) { if (bdev_is_partition(hd) && !bdev_nr_sectors(hd)) continue; if (queue_is_mq(gp->queue)) inflight = blk_mq_in_flight(gp->queue, hd); else inflight = part_in_flight(hd); if (inflight) { part_stat_lock(); update_io_ticks(hd, jiffies, true); part_stat_unlock(); } part_stat_read_all(hd, &stat); seq_printf(seqf, "%4d %7d %pg " "%lu %lu %lu %u " "%lu %lu %lu %u " "%u %u %u " "%lu %lu %lu %u " "%lu %u" "\n", MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd, stat.ios[STAT_READ], stat.merges[STAT_READ], stat.sectors[STAT_READ], (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC), stat.ios[STAT_WRITE], stat.merges[STAT_WRITE], stat.sectors[STAT_WRITE], (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC), inflight, jiffies_to_msecs(stat.io_ticks), (unsigned int)div_u64(stat.nsecs[STAT_READ] + stat.nsecs[STAT_WRITE] + stat.nsecs[STAT_DISCARD] + stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC), stat.ios[STAT_DISCARD], stat.merges[STAT_DISCARD], stat.sectors[STAT_DISCARD], (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC), stat.ios[STAT_FLUSH], (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC) ); } rcu_read_unlock(); return 0; } static const struct seq_operations diskstats_op = { .start = disk_seqf_start, .next = disk_seqf_next, .stop = disk_seqf_stop, .show = diskstats_show }; static int __init proc_genhd_init(void) { proc_create_seq("diskstats", 0, NULL, &diskstats_op); proc_create_seq("partitions", 0, NULL, &partitions_op); return 0; } module_init(proc_genhd_init); #endif /* CONFIG_PROC_FS */ dev_t part_devt(struct gendisk *disk, u8 partno) { struct block_device *part; dev_t devt = 0; rcu_read_lock(); part = xa_load(&disk->part_tbl, partno); if (part) devt = part->bd_dev; rcu_read_unlock(); return devt; } dev_t blk_lookup_devt(const char *name, int partno) { dev_t devt = MKDEV(0, 0); struct class_dev_iter iter; struct device *dev; class_dev_iter_init(&iter, &block_class, NULL, &disk_type); while ((dev = class_dev_iter_next(&iter))) { struct gendisk *disk = dev_to_disk(dev); if (strcmp(dev_name(dev), name)) continue; if (partno < disk->minors) { /* We need to return the right devno, even * if the partition doesn't exist yet. */ devt = MKDEV(MAJOR(dev->devt), MINOR(dev->devt) + partno); } else { devt = part_devt(disk, partno); if (devt) break; } } class_dev_iter_exit(&iter); return devt; } struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id, struct lock_class_key *lkclass) { struct gendisk *disk; disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id); if (!disk) return NULL; if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0)) goto out_free_disk; disk->bdi = bdi_alloc(node_id); if (!disk->bdi) goto out_free_bioset; /* bdev_alloc() might need the queue, set before the first call */ disk->queue = q; disk->part0 = bdev_alloc(disk, 0); if (!disk->part0) goto out_free_bdi; disk->node_id = node_id; mutex_init(&disk->open_mutex); xa_init(&disk->part_tbl); if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL)) goto out_destroy_part_tbl; if (blkcg_init_disk(disk)) goto out_erase_part0; rand_initialize_disk(disk); disk_to_dev(disk)->class = &block_class; disk_to_dev(disk)->type = &disk_type; device_initialize(disk_to_dev(disk)); inc_diskseq(disk); q->disk = disk; lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0); #ifdef CONFIG_BLOCK_HOLDER_DEPRECATED INIT_LIST_HEAD(&disk->slave_bdevs); #endif return disk; out_erase_part0: xa_erase(&disk->part_tbl, 0); out_destroy_part_tbl: xa_destroy(&disk->part_tbl); disk->part0->bd_disk = NULL; iput(disk->part0->bd_inode); out_free_bdi: bdi_put(disk->bdi); out_free_bioset: bioset_exit(&disk->bio_split); out_free_disk: kfree(disk); return NULL; } struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass) { struct request_queue *q; struct gendisk *disk; q = blk_alloc_queue(node); if (!q) return NULL; disk = __alloc_disk_node(q, node, lkclass); if (!disk) { blk_put_queue(q); return NULL; } set_bit(GD_OWNS_QUEUE, &disk->state); return disk; } EXPORT_SYMBOL(__blk_alloc_disk); /** * put_disk - decrements the gendisk refcount * @disk: the struct gendisk to decrement the refcount for * * This decrements the refcount for the struct gendisk. When this reaches 0 * we'll have disk_release() called. * * Note: for blk-mq disk put_disk must be called before freeing the tag_set * when handling probe errors (that is before add_disk() is called). * * Context: Any context, but the last reference must not be dropped from * atomic context. */ void put_disk(struct gendisk *disk) { if (disk) put_device(disk_to_dev(disk)); } EXPORT_SYMBOL(put_disk); static void set_disk_ro_uevent(struct gendisk *gd, int ro) { char event[] = "DISK_RO=1"; char *envp[] = { event, NULL }; if (!ro) event[8] = '0'; kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp); } /** * set_disk_ro - set a gendisk read-only * @disk: gendisk to operate on * @read_only: %true to set the disk read-only, %false set the disk read/write * * This function is used to indicate whether a given disk device should have its * read-only flag set. set_disk_ro() is typically used by device drivers to * indicate whether the underlying physical device is write-protected. */ void set_disk_ro(struct gendisk *disk, bool read_only) { if (read_only) { if (test_and_set_bit(GD_READ_ONLY, &disk->state)) return; } else { if (!test_and_clear_bit(GD_READ_ONLY, &disk->state)) return; } set_disk_ro_uevent(disk, read_only); } EXPORT_SYMBOL(set_disk_ro); void inc_diskseq(struct gendisk *disk) { disk->diskseq = atomic64_inc_return(&diskseq); }