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Diffstat (limited to 'drivers/block/xen-blkback/common.h')
| -rw-r--r-- | drivers/block/xen-blkback/common.h | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/drivers/block/xen-blkback/common.h b/drivers/block/xen-blkback/common.h new file mode 100644 index 000000000000..9e40b283a468 --- /dev/null +++ b/drivers/block/xen-blkback/common.h @@ -0,0 +1,233 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation; or, when distributed + * separately from the Linux kernel or incorporated into other + * software packages, subject to the following license: + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this source file (the "Software"), to deal in the Software without + * restriction, including without limitation the rights to use, copy, modify, + * merge, publish, distribute, sublicense, and/or sell copies of the Software, + * and to permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS + * IN THE SOFTWARE. + */ + +#ifndef __XEN_BLKIF__BACKEND__COMMON_H__ +#define __XEN_BLKIF__BACKEND__COMMON_H__ + +#include <linux/version.h> +#include <linux/module.h> +#include <linux/interrupt.h> +#include <linux/slab.h> +#include <linux/blkdev.h> +#include <linux/vmalloc.h> +#include <linux/wait.h> +#include <linux/io.h> +#include <asm/setup.h> +#include <asm/pgalloc.h> +#include <asm/hypervisor.h> +#include <xen/grant_table.h> +#include <xen/xenbus.h> +#include <xen/interface/io/ring.h> +#include <xen/interface/io/blkif.h> +#include <xen/interface/io/protocols.h> + +#define DRV_PFX "xen-blkback:" +#define DPRINTK(fmt, args...) \ + pr_debug(DRV_PFX "(%s:%d) " fmt ".\n", \ + __func__, __LINE__, ##args) + + +/* Not a real protocol. Used to generate ring structs which contain + * the elements common to all protocols only. This way we get a + * compiler-checkable way to use common struct elements, so we can + * avoid using switch(protocol) in a number of places. */ +struct blkif_common_request { + char dummy; +}; +struct blkif_common_response { + char dummy; +}; + +/* i386 protocol version */ +#pragma pack(push, 4) +struct blkif_x86_32_request { + uint8_t operation; /* BLKIF_OP_??? */ + uint8_t nr_segments; /* number of segments */ + blkif_vdev_t handle; /* only for read/write requests */ + uint64_t id; /* private guest value, echoed in resp */ + blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ + struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; +}; +struct blkif_x86_32_response { + uint64_t id; /* copied from request */ + uint8_t operation; /* copied from request */ + int16_t status; /* BLKIF_RSP_??? */ +}; +#pragma pack(pop) + +/* x86_64 protocol version */ +struct blkif_x86_64_request { + uint8_t operation; /* BLKIF_OP_??? */ + uint8_t nr_segments; /* number of segments */ + blkif_vdev_t handle; /* only for read/write requests */ + uint64_t __attribute__((__aligned__(8))) id; + blkif_sector_t sector_number;/* start sector idx on disk (r/w only) */ + struct blkif_request_segment seg[BLKIF_MAX_SEGMENTS_PER_REQUEST]; +}; +struct blkif_x86_64_response { + uint64_t __attribute__((__aligned__(8))) id; + uint8_t operation; /* copied from request */ + int16_t status; /* BLKIF_RSP_??? */ +}; + +DEFINE_RING_TYPES(blkif_common, struct blkif_common_request, + struct blkif_common_response); +DEFINE_RING_TYPES(blkif_x86_32, struct blkif_x86_32_request, + struct blkif_x86_32_response); +DEFINE_RING_TYPES(blkif_x86_64, struct blkif_x86_64_request, + struct blkif_x86_64_response); + +union blkif_back_rings { + struct blkif_back_ring native; + struct blkif_common_back_ring common; + struct blkif_x86_32_back_ring x86_32; + struct blkif_x86_64_back_ring x86_64; +}; + +enum blkif_protocol { + BLKIF_PROTOCOL_NATIVE = 1, + BLKIF_PROTOCOL_X86_32 = 2, + BLKIF_PROTOCOL_X86_64 = 3, +}; + +struct xen_vbd { + /* What the domain refers to this vbd as. */ + blkif_vdev_t handle; + /* Non-zero -> read-only */ + unsigned char readonly; + /* VDISK_xxx */ + unsigned char type; + /* phys device that this vbd maps to. */ + u32 pdevice; + struct block_device *bdev; + /* Cached size parameter. */ + sector_t size; + bool flush_support; +}; + +struct backend_info; + +struct xen_blkif { + /* Unique identifier for this interface. */ + domid_t domid; + unsigned int handle; + /* Physical parameters of the comms window. */ + unsigned int irq; + /* Comms information. */ + enum blkif_protocol blk_protocol; + union blkif_back_rings blk_rings; + struct vm_struct *blk_ring_area; + /* The VBD attached to this interface. */ + struct xen_vbd vbd; + /* Back pointer to the backend_info. */ + struct backend_info *be; + /* Private fields. */ + spinlock_t blk_ring_lock; + atomic_t refcnt; + + wait_queue_head_t wq; + /* One thread per one blkif. */ + struct task_struct *xenblkd; + unsigned int waiting_reqs; + + /* statistics */ + unsigned long st_print; + int st_rd_req; + int st_wr_req; + int st_oo_req; + int st_f_req; + int st_rd_sect; + int st_wr_sect; + + wait_queue_head_t waiting_to_free; + + grant_handle_t shmem_handle; + grant_ref_t shmem_ref; +}; + + +#define vbd_sz(_v) ((_v)->bdev->bd_part ? \ + (_v)->bdev->bd_part->nr_sects : \ + get_capacity((_v)->bdev->bd_disk)) + +#define xen_blkif_get(_b) (atomic_inc(&(_b)->refcnt)) +#define xen_blkif_put(_b) \ + do { \ + if (atomic_dec_and_test(&(_b)->refcnt)) \ + wake_up(&(_b)->waiting_to_free);\ + } while (0) + +struct phys_req { + unsigned short dev; + unsigned short nr_sects; + struct block_device *bdev; + blkif_sector_t sector_number; +}; +int xen_blkif_interface_init(void); + +int xen_blkif_xenbus_init(void); + +irqreturn_t xen_blkif_be_int(int irq, void *dev_id); +int xen_blkif_schedule(void *arg); + +int xen_blkbk_flush_diskcache(struct xenbus_transaction xbt, + struct backend_info *be, int state); + +struct xenbus_device *xen_blkbk_xenbus(struct backend_info *be); + +static inline void blkif_get_x86_32_req(struct blkif_request *dst, + struct blkif_x86_32_request *src) +{ + int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST; + dst->operation = src->operation; + dst->nr_segments = src->nr_segments; + dst->handle = src->handle; + dst->id = src->id; + dst->u.rw.sector_number = src->sector_number; + barrier(); + if (n > dst->nr_segments) + n = dst->nr_segments; + for (i = 0; i < n; i++) + dst->u.rw.seg[i] = src->seg[i]; +} + +static inline void blkif_get_x86_64_req(struct blkif_request *dst, + struct blkif_x86_64_request *src) +{ + int i, n = BLKIF_MAX_SEGMENTS_PER_REQUEST; + dst->operation = src->operation; + dst->nr_segments = src->nr_segments; + dst->handle = src->handle; + dst->id = src->id; + dst->u.rw.sector_number = src->sector_number; + barrier(); + if (n > dst->nr_segments) + n = dst->nr_segments; + for (i = 0; i < n; i++) + dst->u.rw.seg[i] = src->seg[i]; +} + +#endif /* __XEN_BLKIF__BACKEND__COMMON_H__ */ |