| /* |
| * Copyright (C) 2001, 2002 Sistina Software (UK) Limited. |
| * Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved. |
| * |
| * This file is released under the GPL. |
| */ |
| |
| #include "dm.h" |
| #include "dm-bio-list.h" |
| #include "dm-uevent.h" |
| |
| #include <linux/init.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/moduleparam.h> |
| #include <linux/blkpg.h> |
| #include <linux/bio.h> |
| #include <linux/buffer_head.h> |
| #include <linux/mempool.h> |
| #include <linux/slab.h> |
| #include <linux/idr.h> |
| #include <linux/hdreg.h> |
| #include <linux/blktrace_api.h> |
| #include <linux/smp_lock.h> |
| |
| #define DM_MSG_PREFIX "core" |
| |
| static const char *_name = DM_NAME; |
| |
| static unsigned int major = 0; |
| static unsigned int _major = 0; |
| |
| static DEFINE_SPINLOCK(_minor_lock); |
| /* |
| * One of these is allocated per bio. |
| */ |
| struct dm_io { |
| struct mapped_device *md; |
| int error; |
| atomic_t io_count; |
| struct bio *bio; |
| unsigned long start_time; |
| }; |
| |
| /* |
| * One of these is allocated per target within a bio. Hopefully |
| * this will be simplified out one day. |
| */ |
| struct dm_target_io { |
| struct dm_io *io; |
| struct dm_target *ti; |
| union map_info info; |
| }; |
| |
| union map_info *dm_get_mapinfo(struct bio *bio) |
| { |
| if (bio && bio->bi_private) |
| return &((struct dm_target_io *)bio->bi_private)->info; |
| return NULL; |
| } |
| |
| #define MINOR_ALLOCED ((void *)-1) |
| |
| /* |
| * Bits for the md->flags field. |
| */ |
| #define DMF_BLOCK_IO 0 |
| #define DMF_SUSPENDED 1 |
| #define DMF_FROZEN 2 |
| #define DMF_FREEING 3 |
| #define DMF_DELETING 4 |
| #define DMF_NOFLUSH_SUSPENDING 5 |
| |
| /* |
| * Work processed by per-device workqueue. |
| */ |
| struct dm_wq_req { |
| enum { |
| DM_WQ_FLUSH_ALL, |
| DM_WQ_FLUSH_DEFERRED, |
| } type; |
| struct work_struct work; |
| struct mapped_device *md; |
| void *context; |
| }; |
| |
| struct mapped_device { |
| struct rw_semaphore io_lock; |
| struct mutex suspend_lock; |
| spinlock_t pushback_lock; |
| rwlock_t map_lock; |
| atomic_t holders; |
| atomic_t open_count; |
| |
| unsigned long flags; |
| |
| struct request_queue *queue; |
| struct gendisk *disk; |
| char name[16]; |
| |
| void *interface_ptr; |
| |
| /* |
| * A list of ios that arrived while we were suspended. |
| */ |
| atomic_t pending; |
| wait_queue_head_t wait; |
| struct bio_list deferred; |
| struct bio_list pushback; |
| |
| /* |
| * Processing queue (flush/barriers) |
| */ |
| struct workqueue_struct *wq; |
| |
| /* |
| * The current mapping. |
| */ |
| struct dm_table *map; |
| |
| /* |
| * io objects are allocated from here. |
| */ |
| mempool_t *io_pool; |
| mempool_t *tio_pool; |
| |
| struct bio_set *bs; |
| |
| /* |
| * Event handling. |
| */ |
| atomic_t event_nr; |
| wait_queue_head_t eventq; |
| atomic_t uevent_seq; |
| struct list_head uevent_list; |
| spinlock_t uevent_lock; /* Protect access to uevent_list */ |
| |
| /* |
| * freeze/thaw support require holding onto a super block |
| */ |
| struct super_block *frozen_sb; |
| struct block_device *suspended_bdev; |
| |
| /* forced geometry settings */ |
| struct hd_geometry geometry; |
| }; |
| |
| #define MIN_IOS 256 |
| static struct kmem_cache *_io_cache; |
| static struct kmem_cache *_tio_cache; |
| |
| static int __init local_init(void) |
| { |
| int r; |
| |
| /* allocate a slab for the dm_ios */ |
| _io_cache = KMEM_CACHE(dm_io, 0); |
| if (!_io_cache) |
| return -ENOMEM; |
| |
| /* allocate a slab for the target ios */ |
| _tio_cache = KMEM_CACHE(dm_target_io, 0); |
| if (!_tio_cache) { |
| kmem_cache_destroy(_io_cache); |
| return -ENOMEM; |
| } |
| |
| r = dm_uevent_init(); |
| if (r) { |
| kmem_cache_destroy(_tio_cache); |
| kmem_cache_destroy(_io_cache); |
| return r; |
| } |
| |
| _major = major; |
| r = register_blkdev(_major, _name); |
| if (r < 0) { |
| kmem_cache_destroy(_tio_cache); |
| kmem_cache_destroy(_io_cache); |
| dm_uevent_exit(); |
| return r; |
| } |
| |
| if (!_major) |
| _major = r; |
| |
| return 0; |
| } |
| |
| static void local_exit(void) |
| { |
| kmem_cache_destroy(_tio_cache); |
| kmem_cache_destroy(_io_cache); |
| unregister_blkdev(_major, _name); |
| dm_uevent_exit(); |
| |
| _major = 0; |
| |
| DMINFO("cleaned up"); |
| } |
| |
| static int (*_inits[])(void) __initdata = { |
| local_init, |
| dm_target_init, |
| dm_linear_init, |
| dm_stripe_init, |
| dm_kcopyd_init, |
| dm_interface_init, |
| }; |
| |
| static void (*_exits[])(void) = { |
| local_exit, |
| dm_target_exit, |
| dm_linear_exit, |
| dm_stripe_exit, |
| dm_kcopyd_exit, |
| dm_interface_exit, |
| }; |
| |
| static int __init dm_init(void) |
| { |
| const int count = ARRAY_SIZE(_inits); |
| |
| int r, i; |
| |
| for (i = 0; i < count; i++) { |
| r = _inits[i](); |
| if (r) |
| goto bad; |
| } |
| |
| return 0; |
| |
| bad: |
| while (i--) |
| _exits[i](); |
| |
| return r; |
| } |
| |
| static void __exit dm_exit(void) |
| { |
| int i = ARRAY_SIZE(_exits); |
| |
| while (i--) |
| _exits[i](); |
| } |
| |
| /* |
| * Block device functions |
| */ |
| static int dm_blk_open(struct inode *inode, struct file *file) |
| { |
| struct mapped_device *md; |
| |
| spin_lock(&_minor_lock); |
| |
| md = inode->i_bdev->bd_disk->private_data; |
| if (!md) |
| goto out; |
| |
| if (test_bit(DMF_FREEING, &md->flags) || |
| test_bit(DMF_DELETING, &md->flags)) { |
| md = NULL; |
| goto out; |
| } |
| |
| dm_get(md); |
| atomic_inc(&md->open_count); |
| |
| out: |
| spin_unlock(&_minor_lock); |
| |
| return md ? 0 : -ENXIO; |
| } |
| |
| static int dm_blk_close(struct inode *inode, struct file *file) |
| { |
| struct mapped_device *md; |
| |
| md = inode->i_bdev->bd_disk->private_data; |
| atomic_dec(&md->open_count); |
| dm_put(md); |
| return 0; |
| } |
| |
| int dm_open_count(struct mapped_device *md) |
| { |
| return atomic_read(&md->open_count); |
| } |
| |
| /* |
| * Guarantees nothing is using the device before it's deleted. |
| */ |
| int dm_lock_for_deletion(struct mapped_device *md) |
| { |
| int r = 0; |
| |
| spin_lock(&_minor_lock); |
| |
| if (dm_open_count(md)) |
| r = -EBUSY; |
| else |
| set_bit(DMF_DELETING, &md->flags); |
| |
| spin_unlock(&_minor_lock); |
| |
| return r; |
| } |
| |
| static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo) |
| { |
| struct mapped_device *md = bdev->bd_disk->private_data; |
| |
| return dm_get_geometry(md, geo); |
| } |
| |
| static int dm_blk_ioctl(struct inode *inode, struct file *file, |
| unsigned int cmd, unsigned long arg) |
| { |
| struct mapped_device *md; |
| struct dm_table *map; |
| struct dm_target *tgt; |
| int r = -ENOTTY; |
| |
| /* We don't really need this lock, but we do need 'inode'. */ |
| unlock_kernel(); |
| |
| md = inode->i_bdev->bd_disk->private_data; |
| |
| map = dm_get_table(md); |
| |
| if (!map || !dm_table_get_size(map)) |
| goto out; |
| |
| /* We only support devices that have a single target */ |
| if (dm_table_get_num_targets(map) != 1) |
| goto out; |
| |
| tgt = dm_table_get_target(map, 0); |
| |
| if (dm_suspended(md)) { |
| r = -EAGAIN; |
| goto out; |
| } |
| |
| if (tgt->type->ioctl) |
| r = tgt->type->ioctl(tgt, cmd, arg); |
| |
| out: |
| dm_table_put(map); |
| |
| lock_kernel(); |
| return r; |
| } |
| |
| static struct dm_io *alloc_io(struct mapped_device *md) |
| { |
| return mempool_alloc(md->io_pool, GFP_NOIO); |
| } |
| |
| static void free_io(struct mapped_device *md, struct dm_io *io) |
| { |
| mempool_free(io, md->io_pool); |
| } |
| |
| static struct dm_target_io *alloc_tio(struct mapped_device *md) |
| { |
| return mempool_alloc(md->tio_pool, GFP_NOIO); |
| } |
| |
| static void free_tio(struct mapped_device *md, struct dm_target_io *tio) |
| { |
| mempool_free(tio, md->tio_pool); |
| } |
| |
| static void start_io_acct(struct dm_io *io) |
| { |
| struct mapped_device *md = io->md; |
| int cpu; |
| |
| io->start_time = jiffies; |
| |
| cpu = part_stat_lock(); |
| part_round_stats(cpu, &dm_disk(md)->part0); |
| part_stat_unlock(); |
| dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending); |
| } |
| |
| static int end_io_acct(struct dm_io *io) |
| { |
| struct mapped_device *md = io->md; |
| struct bio *bio = io->bio; |
| unsigned long duration = jiffies - io->start_time; |
| int pending, cpu; |
| int rw = bio_data_dir(bio); |
| |
| cpu = part_stat_lock(); |
| part_round_stats(cpu, &dm_disk(md)->part0); |
| part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration); |
| part_stat_unlock(); |
| |
| dm_disk(md)->part0.in_flight = pending = |
| atomic_dec_return(&md->pending); |
| |
| return !pending; |
| } |
| |
| /* |
| * Add the bio to the list of deferred io. |
| */ |
| static int queue_io(struct mapped_device *md, struct bio *bio) |
| { |
| down_write(&md->io_lock); |
| |
| if (!test_bit(DMF_BLOCK_IO, &md->flags)) { |
| up_write(&md->io_lock); |
| return 1; |
| } |
| |
| bio_list_add(&md->deferred, bio); |
| |
| up_write(&md->io_lock); |
| return 0; /* deferred successfully */ |
| } |
| |
| /* |
| * Everyone (including functions in this file), should use this |
| * function to access the md->map field, and make sure they call |
| * dm_table_put() when finished. |
| */ |
| struct dm_table *dm_get_table(struct mapped_device *md) |
| { |
| struct dm_table *t; |
| |
| read_lock(&md->map_lock); |
| t = md->map; |
| if (t) |
| dm_table_get(t); |
| read_unlock(&md->map_lock); |
| |
| return t; |
| } |
| |
| /* |
| * Get the geometry associated with a dm device |
| */ |
| int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo) |
| { |
| *geo = md->geometry; |
| |
| return 0; |
| } |
| |
| /* |
| * Set the geometry of a device. |
| */ |
| int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo) |
| { |
| sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors; |
| |
| if (geo->start > sz) { |
| DMWARN("Start sector is beyond the geometry limits."); |
| return -EINVAL; |
| } |
| |
| md->geometry = *geo; |
| |
| return 0; |
| } |
| |
| /*----------------------------------------------------------------- |
| * CRUD START: |
| * A more elegant soln is in the works that uses the queue |
| * merge fn, unfortunately there are a couple of changes to |
| * the block layer that I want to make for this. So in the |
| * interests of getting something for people to use I give |
| * you this clearly demarcated crap. |
| *---------------------------------------------------------------*/ |
| |
| static int __noflush_suspending(struct mapped_device *md) |
| { |
| return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); |
| } |
| |
| /* |
| * Decrements the number of outstanding ios that a bio has been |
| * cloned into, completing the original io if necc. |
| */ |
| static void dec_pending(struct dm_io *io, int error) |
| { |
| unsigned long flags; |
| |
| /* Push-back supersedes any I/O errors */ |
| if (error && !(io->error > 0 && __noflush_suspending(io->md))) |
| io->error = error; |
| |
| if (atomic_dec_and_test(&io->io_count)) { |
| if (io->error == DM_ENDIO_REQUEUE) { |
| /* |
| * Target requested pushing back the I/O. |
| * This must be handled before the sleeper on |
| * suspend queue merges the pushback list. |
| */ |
| spin_lock_irqsave(&io->md->pushback_lock, flags); |
| if (__noflush_suspending(io->md)) |
| bio_list_add(&io->md->pushback, io->bio); |
| else |
| /* noflush suspend was interrupted. */ |
| io->error = -EIO; |
| spin_unlock_irqrestore(&io->md->pushback_lock, flags); |
| } |
| |
| if (end_io_acct(io)) |
| /* nudge anyone waiting on suspend queue */ |
| wake_up(&io->md->wait); |
| |
| if (io->error != DM_ENDIO_REQUEUE) { |
| blk_add_trace_bio(io->md->queue, io->bio, |
| BLK_TA_COMPLETE); |
| |
| bio_endio(io->bio, io->error); |
| } |
| |
| free_io(io->md, io); |
| } |
| } |
| |
| static void clone_endio(struct bio *bio, int error) |
| { |
| int r = 0; |
| struct dm_target_io *tio = bio->bi_private; |
| struct mapped_device *md = tio->io->md; |
| dm_endio_fn endio = tio->ti->type->end_io; |
| |
| if (!bio_flagged(bio, BIO_UPTODATE) && !error) |
| error = -EIO; |
| |
| if (endio) { |
| r = endio(tio->ti, bio, error, &tio->info); |
| if (r < 0 || r == DM_ENDIO_REQUEUE) |
| /* |
| * error and requeue request are handled |
| * in dec_pending(). |
| */ |
| error = r; |
| else if (r == DM_ENDIO_INCOMPLETE) |
| /* The target will handle the io */ |
| return; |
| else if (r) { |
| DMWARN("unimplemented target endio return value: %d", r); |
| BUG(); |
| } |
| } |
| |
| dec_pending(tio->io, error); |
| |
| /* |
| * Store md for cleanup instead of tio which is about to get freed. |
| */ |
| bio->bi_private = md->bs; |
| |
| bio_put(bio); |
| free_tio(md, tio); |
| } |
| |
| static sector_t max_io_len(struct mapped_device *md, |
| sector_t sector, struct dm_target *ti) |
| { |
| sector_t offset = sector - ti->begin; |
| sector_t len = ti->len - offset; |
| |
| /* |
| * Does the target need to split even further ? |
| */ |
| if (ti->split_io) { |
| sector_t boundary; |
| boundary = ((offset + ti->split_io) & ~(ti->split_io - 1)) |
| - offset; |
| if (len > boundary) |
| len = boundary; |
| } |
| |
| return len; |
| } |
| |
| static void __map_bio(struct dm_target *ti, struct bio *clone, |
| struct dm_target_io *tio) |
| { |
| int r; |
| sector_t sector; |
| struct mapped_device *md; |
| |
| /* |
| * Sanity checks. |
| */ |
| BUG_ON(!clone->bi_size); |
| |
| clone->bi_end_io = clone_endio; |
| clone->bi_private = tio; |
| |
| /* |
| * Map the clone. If r == 0 we don't need to do |
| * anything, the target has assumed ownership of |
| * this io. |
| */ |
| atomic_inc(&tio->io->io_count); |
| sector = clone->bi_sector; |
| r = ti->type->map(ti, clone, &tio->info); |
| if (r == DM_MAPIO_REMAPPED) { |
| /* the bio has been remapped so dispatch it */ |
| |
| blk_add_trace_remap(bdev_get_queue(clone->bi_bdev), clone, |
| tio->io->bio->bi_bdev->bd_dev, |
| clone->bi_sector, sector); |
| |
| generic_make_request(clone); |
| } else if (r < 0 || r == DM_MAPIO_REQUEUE) { |
| /* error the io and bail out, or requeue it if needed */ |
| md = tio->io->md; |
| dec_pending(tio->io, r); |
| /* |
| * Store bio_set for cleanup. |
| */ |
| clone->bi_private = md->bs; |
| bio_put(clone); |
| free_tio(md, tio); |
| } else if (r) { |
| DMWARN("unimplemented target map return value: %d", r); |
| BUG(); |
| } |
| } |
| |
| struct clone_info { |
| struct mapped_device *md; |
| struct dm_table *map; |
| struct bio *bio; |
| struct dm_io *io; |
| sector_t sector; |
| sector_t sector_count; |
| unsigned short idx; |
| }; |
| |
| static void dm_bio_destructor(struct bio *bio) |
| { |
| struct bio_set *bs = bio->bi_private; |
| |
| bio_free(bio, bs); |
| } |
| |
| /* |
| * Creates a little bio that is just does part of a bvec. |
| */ |
| static struct bio *split_bvec(struct bio *bio, sector_t sector, |
| unsigned short idx, unsigned int offset, |
| unsigned int len, struct bio_set *bs) |
| { |
| struct bio *clone; |
| struct bio_vec *bv = bio->bi_io_vec + idx; |
| |
| clone = bio_alloc_bioset(GFP_NOIO, 1, bs); |
| clone->bi_destructor = dm_bio_destructor; |
| *clone->bi_io_vec = *bv; |
| |
| clone->bi_sector = sector; |
| clone->bi_bdev = bio->bi_bdev; |
| clone->bi_rw = bio->bi_rw; |
| clone->bi_vcnt = 1; |
| clone->bi_size = to_bytes(len); |
| clone->bi_io_vec->bv_offset = offset; |
| clone->bi_io_vec->bv_len = clone->bi_size; |
| |
| return clone; |
| } |
| |
| /* |
| * Creates a bio that consists of range of complete bvecs. |
| */ |
| static struct bio *clone_bio(struct bio *bio, sector_t sector, |
| unsigned short idx, unsigned short bv_count, |
| unsigned int len, struct bio_set *bs) |
| { |
| struct bio *clone; |
| |
| clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs); |
| __bio_clone(clone, bio); |
| clone->bi_destructor = dm_bio_destructor; |
| clone->bi_sector = sector; |
| clone->bi_idx = idx; |
| clone->bi_vcnt = idx + bv_count; |
| clone->bi_size = to_bytes(len); |
| clone->bi_flags &= ~(1 << BIO_SEG_VALID); |
| |
| return clone; |
| } |
| |
| static int __clone_and_map(struct clone_info *ci) |
| { |
| struct bio *clone, *bio = ci->bio; |
| struct dm_target *ti; |
| sector_t len = 0, max; |
| struct dm_target_io *tio; |
| |
| ti = dm_table_find_target(ci->map, ci->sector); |
| if (!dm_target_is_valid(ti)) |
| return -EIO; |
| |
| max = max_io_len(ci->md, ci->sector, ti); |
| |
| /* |
| * Allocate a target io object. |
| */ |
| tio = alloc_tio(ci->md); |
| tio->io = ci->io; |
| tio->ti = ti; |
| memset(&tio->info, 0, sizeof(tio->info)); |
| |
| if (ci->sector_count <= max) { |
| /* |
| * Optimise for the simple case where we can do all of |
| * the remaining io with a single clone. |
| */ |
| clone = clone_bio(bio, ci->sector, ci->idx, |
| bio->bi_vcnt - ci->idx, ci->sector_count, |
| ci->md->bs); |
| __map_bio(ti, clone, tio); |
| ci->sector_count = 0; |
| |
| } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) { |
| /* |
| * There are some bvecs that don't span targets. |
| * Do as many of these as possible. |
| */ |
| int i; |
| sector_t remaining = max; |
| sector_t bv_len; |
| |
| for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) { |
| bv_len = to_sector(bio->bi_io_vec[i].bv_len); |
| |
| if (bv_len > remaining) |
| break; |
| |
| remaining -= bv_len; |
| len += bv_len; |
| } |
| |
| clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len, |
| ci->md->bs); |
| __map_bio(ti, clone, tio); |
| |
| ci->sector += len; |
| ci->sector_count -= len; |
| ci->idx = i; |
| |
| } else { |
| /* |
| * Handle a bvec that must be split between two or more targets. |
| */ |
| struct bio_vec *bv = bio->bi_io_vec + ci->idx; |
| sector_t remaining = to_sector(bv->bv_len); |
| unsigned int offset = 0; |
| |
| do { |
| if (offset) { |
| ti = dm_table_find_target(ci->map, ci->sector); |
| if (!dm_target_is_valid(ti)) |
| return -EIO; |
| |
| max = max_io_len(ci->md, ci->sector, ti); |
| |
| tio = alloc_tio(ci->md); |
| tio->io = ci->io; |
| tio->ti = ti; |
| memset(&tio->info, 0, sizeof(tio->info)); |
| } |
| |
| len = min(remaining, max); |
| |
| clone = split_bvec(bio, ci->sector, ci->idx, |
| bv->bv_offset + offset, len, |
| ci->md->bs); |
| |
| __map_bio(ti, clone, tio); |
| |
| ci->sector += len; |
| ci->sector_count -= len; |
| offset += to_bytes(len); |
| } while (remaining -= len); |
| |
| ci->idx++; |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * Split the bio into several clones. |
| */ |
| static int __split_bio(struct mapped_device *md, struct bio *bio) |
| { |
| struct clone_info ci; |
| int error = 0; |
| |
| ci.map = dm_get_table(md); |
| if (unlikely(!ci.map)) |
| return -EIO; |
| |
| ci.md = md; |
| ci.bio = bio; |
| ci.io = alloc_io(md); |
| ci.io->error = 0; |
| atomic_set(&ci.io->io_count, 1); |
| ci.io->bio = bio; |
| ci.io->md = md; |
| ci.sector = bio->bi_sector; |
| ci.sector_count = bio_sectors(bio); |
| ci.idx = bio->bi_idx; |
| |
| start_io_acct(ci.io); |
| while (ci.sector_count && !error) |
| error = __clone_and_map(&ci); |
| |
| /* drop the extra reference count */ |
| dec_pending(ci.io, error); |
| dm_table_put(ci.map); |
| |
| return 0; |
| } |
| /*----------------------------------------------------------------- |
| * CRUD END |
| *---------------------------------------------------------------*/ |
| |
| static int dm_merge_bvec(struct request_queue *q, |
| struct bvec_merge_data *bvm, |
| struct bio_vec *biovec) |
| { |
| struct mapped_device *md = q->queuedata; |
| struct dm_table *map = dm_get_table(md); |
| struct dm_target *ti; |
| sector_t max_sectors; |
| int max_size = 0; |
| |
| if (unlikely(!map)) |
| goto out; |
| |
| ti = dm_table_find_target(map, bvm->bi_sector); |
| if (!dm_target_is_valid(ti)) |
| goto out_table; |
| |
| /* |
| * Find maximum amount of I/O that won't need splitting |
| */ |
| max_sectors = min(max_io_len(md, bvm->bi_sector, ti), |
| (sector_t) BIO_MAX_SECTORS); |
| max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size; |
| if (max_size < 0) |
| max_size = 0; |
| |
| /* |
| * merge_bvec_fn() returns number of bytes |
| * it can accept at this offset |
| * max is precomputed maximal io size |
| */ |
| if (max_size && ti->type->merge) |
| max_size = ti->type->merge(ti, bvm, biovec, max_size); |
| |
| out_table: |
| dm_table_put(map); |
| |
| out: |
| /* |
| * Always allow an entire first page |
| */ |
| if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT)) |
| max_size = biovec->bv_len; |
| |
| return max_size; |
| } |
| |
| /* |
| * The request function that just remaps the bio built up by |
| * dm_merge_bvec. |
| */ |
| static int dm_request(struct request_queue *q, struct bio *bio) |
| { |
| int r = -EIO; |
| int rw = bio_data_dir(bio); |
| struct mapped_device *md = q->queuedata; |
| int cpu; |
| |
| /* |
| * There is no use in forwarding any barrier request since we can't |
| * guarantee it is (or can be) handled by the targets correctly. |
| */ |
| if (unlikely(bio_barrier(bio))) { |
| bio_endio(bio, -EOPNOTSUPP); |
| return 0; |
| } |
| |
| down_read(&md->io_lock); |
| |
| cpu = part_stat_lock(); |
| part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]); |
| part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio)); |
| part_stat_unlock(); |
| |
| /* |
| * If we're suspended we have to queue |
| * this io for later. |
| */ |
| while (test_bit(DMF_BLOCK_IO, &md->flags)) { |
| up_read(&md->io_lock); |
| |
| if (bio_rw(bio) != READA) |
| r = queue_io(md, bio); |
| |
| if (r <= 0) |
| goto out_req; |
| |
| /* |
| * We're in a while loop, because someone could suspend |
| * before we get to the following read lock. |
| */ |
| down_read(&md->io_lock); |
| } |
| |
| r = __split_bio(md, bio); |
| up_read(&md->io_lock); |
| |
| out_req: |
| if (r < 0) |
| bio_io_error(bio); |
| |
| return 0; |
| } |
| |
| static void dm_unplug_all(struct request_queue *q) |
| { |
| struct mapped_device *md = q->queuedata; |
| struct dm_table *map = dm_get_table(md); |
| |
| if (map) { |
| dm_table_unplug_all(map); |
| dm_table_put(map); |
| } |
| } |
| |
| static int dm_any_congested(void *congested_data, int bdi_bits) |
| { |
| int r; |
| struct mapped_device *md = (struct mapped_device *) congested_data; |
| struct dm_table *map = dm_get_table(md); |
| |
| if (!map || test_bit(DMF_BLOCK_IO, &md->flags)) |
| r = bdi_bits; |
| else |
| r = dm_table_any_congested(map, bdi_bits); |
| |
| dm_table_put(map); |
| return r; |
| } |
| |
| /*----------------------------------------------------------------- |
| * An IDR is used to keep track of allocated minor numbers. |
| *---------------------------------------------------------------*/ |
| static DEFINE_IDR(_minor_idr); |
| |
| static void free_minor(int minor) |
| { |
| spin_lock(&_minor_lock); |
| idr_remove(&_minor_idr, minor); |
| spin_unlock(&_minor_lock); |
| } |
| |
| /* |
| * See if the device with a specific minor # is free. |
| */ |
| static int specific_minor(int minor) |
| { |
| int r, m; |
| |
| if (minor >= (1 << MINORBITS)) |
| return -EINVAL; |
| |
| r = idr_pre_get(&_minor_idr, GFP_KERNEL); |
| if (!r) |
| return -ENOMEM; |
| |
| spin_lock(&_minor_lock); |
| |
| if (idr_find(&_minor_idr, minor)) { |
| r = -EBUSY; |
| goto out; |
| } |
| |
| r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m); |
| if (r) |
| goto out; |
| |
| if (m != minor) { |
| idr_remove(&_minor_idr, m); |
| r = -EBUSY; |
| goto out; |
| } |
| |
| out: |
| spin_unlock(&_minor_lock); |
| return r; |
| } |
| |
| static int next_free_minor(int *minor) |
| { |
| int r, m; |
| |
| r = idr_pre_get(&_minor_idr, GFP_KERNEL); |
| if (!r) |
| return -ENOMEM; |
| |
| spin_lock(&_minor_lock); |
| |
| r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m); |
| if (r) |
| goto out; |
| |
| if (m >= (1 << MINORBITS)) { |
| idr_remove(&_minor_idr, m); |
| r = -ENOSPC; |
| goto out; |
| } |
| |
| *minor = m; |
| |
| out: |
| spin_unlock(&_minor_lock); |
| return r; |
| } |
| |
| static struct block_device_operations dm_blk_dops; |
| |
| /* |
| * Allocate and initialise a blank device with a given minor. |
| */ |
| static struct mapped_device *alloc_dev(int minor) |
| { |
| int r; |
| struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL); |
| void *old_md; |
| |
| if (!md) { |
| DMWARN("unable to allocate device, out of memory."); |
| return NULL; |
| } |
| |
| if (!try_module_get(THIS_MODULE)) |
| goto bad_module_get; |
| |
| /* get a minor number for the dev */ |
| if (minor == DM_ANY_MINOR) |
| r = next_free_minor(&minor); |
| else |
| r = specific_minor(minor); |
| if (r < 0) |
| goto bad_minor; |
| |
| init_rwsem(&md->io_lock); |
| mutex_init(&md->suspend_lock); |
| spin_lock_init(&md->pushback_lock); |
| rwlock_init(&md->map_lock); |
| atomic_set(&md->holders, 1); |
| atomic_set(&md->open_count, 0); |
| atomic_set(&md->event_nr, 0); |
| atomic_set(&md->uevent_seq, 0); |
| INIT_LIST_HEAD(&md->uevent_list); |
| spin_lock_init(&md->uevent_lock); |
| |
| md->queue = blk_alloc_queue(GFP_KERNEL); |
| if (!md->queue) |
| goto bad_queue; |
| |
| md->queue->queuedata = md; |
| md->queue->backing_dev_info.congested_fn = dm_any_congested; |
| md->queue->backing_dev_info.congested_data = md; |
| blk_queue_make_request(md->queue, dm_request); |
| blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY); |
| md->queue->unplug_fn = dm_unplug_all; |
| blk_queue_merge_bvec(md->queue, dm_merge_bvec); |
| |
| md->io_pool = mempool_create_slab_pool(MIN_IOS, _io_cache); |
| if (!md->io_pool) |
| goto bad_io_pool; |
| |
| md->tio_pool = mempool_create_slab_pool(MIN_IOS, _tio_cache); |
| if (!md->tio_pool) |
| goto bad_tio_pool; |
| |
| md->bs = bioset_create(16, 16); |
| if (!md->bs) |
| goto bad_no_bioset; |
| |
| md->disk = alloc_disk(1); |
| if (!md->disk) |
| goto bad_disk; |
| |
| atomic_set(&md->pending, 0); |
| init_waitqueue_head(&md->wait); |
| init_waitqueue_head(&md->eventq); |
| |
| md->disk->major = _major; |
| md->disk->first_minor = minor; |
| md->disk->fops = &dm_blk_dops; |
| md->disk->queue = md->queue; |
| md->disk->private_data = md; |
| sprintf(md->disk->disk_name, "dm-%d", minor); |
| add_disk(md->disk); |
| format_dev_t(md->name, MKDEV(_major, minor)); |
| |
| md->wq = create_singlethread_workqueue("kdmflush"); |
| if (!md->wq) |
| goto bad_thread; |
| |
| /* Populate the mapping, nobody knows we exist yet */ |
| spin_lock(&_minor_lock); |
| old_md = idr_replace(&_minor_idr, md, minor); |
| spin_unlock(&_minor_lock); |
| |
| BUG_ON(old_md != MINOR_ALLOCED); |
| |
| return md; |
| |
| bad_thread: |
| put_disk(md->disk); |
| bad_disk: |
| bioset_free(md->bs); |
| bad_no_bioset: |
| mempool_destroy(md->tio_pool); |
| bad_tio_pool: |
| mempool_destroy(md->io_pool); |
| bad_io_pool: |
| blk_cleanup_queue(md->queue); |
| bad_queue: |
| free_minor(minor); |
| bad_minor: |
| module_put(THIS_MODULE); |
| bad_module_get: |
| kfree(md); |
| return NULL; |
| } |
| |
| static void unlock_fs(struct mapped_device *md); |
| |
| static void free_dev(struct mapped_device *md) |
| { |
| int minor = MINOR(disk_devt(md->disk)); |
| |
| if (md->suspended_bdev) { |
| unlock_fs(md); |
| bdput(md->suspended_bdev); |
| } |
| destroy_workqueue(md->wq); |
| mempool_destroy(md->tio_pool); |
| mempool_destroy(md->io_pool); |
| bioset_free(md->bs); |
| del_gendisk(md->disk); |
| free_minor(minor); |
| |
| spin_lock(&_minor_lock); |
| md->disk->private_data = NULL; |
| spin_unlock(&_minor_lock); |
| |
| put_disk(md->disk); |
| blk_cleanup_queue(md->queue); |
| module_put(THIS_MODULE); |
| kfree(md); |
| } |
| |
| /* |
| * Bind a table to the device. |
| */ |
| static void event_callback(void *context) |
| { |
| unsigned long flags; |
| LIST_HEAD(uevents); |
| struct mapped_device *md = (struct mapped_device *) context; |
| |
| spin_lock_irqsave(&md->uevent_lock, flags); |
| list_splice_init(&md->uevent_list, &uevents); |
| spin_unlock_irqrestore(&md->uevent_lock, flags); |
| |
| dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj); |
| |
| atomic_inc(&md->event_nr); |
| wake_up(&md->eventq); |
| } |
| |
| static void __set_size(struct mapped_device *md, sector_t size) |
| { |
| set_capacity(md->disk, size); |
| |
| mutex_lock(&md->suspended_bdev->bd_inode->i_mutex); |
| i_size_write(md->suspended_bdev->bd_inode, (loff_t)size << SECTOR_SHIFT); |
| mutex_unlock(&md->suspended_bdev->bd_inode->i_mutex); |
| } |
| |
| static int __bind(struct mapped_device *md, struct dm_table *t) |
| { |
| struct request_queue *q = md->queue; |
| sector_t size; |
| |
| size = dm_table_get_size(t); |
| |
| /* |
| * Wipe any geometry if the size of the table changed. |
| */ |
| if (size != get_capacity(md->disk)) |
| memset(&md->geometry, 0, sizeof(md->geometry)); |
| |
| if (md->suspended_bdev) |
| __set_size(md, size); |
| if (size == 0) |
| return 0; |
| |
| dm_table_get(t); |
| dm_table_event_callback(t, event_callback, md); |
| |
| write_lock(&md->map_lock); |
| md->map = t; |
| dm_table_set_restrictions(t, q); |
| write_unlock(&md->map_lock); |
| |
| return 0; |
| } |
| |
| static void __unbind(struct mapped_device *md) |
| { |
| struct dm_table *map = md->map; |
| |
| if (!map) |
| return; |
| |
| dm_table_event_callback(map, NULL, NULL); |
| write_lock(&md->map_lock); |
| md->map = NULL; |
| write_unlock(&md->map_lock); |
| dm_table_put(map); |
| } |
| |
| /* |
| * Constructor for a new device. |
| */ |
| int dm_create(int minor, struct mapped_device **result) |
| { |
| struct mapped_device *md; |
| |
| md = alloc_dev(minor); |
| if (!md) |
| return -ENXIO; |
| |
| *result = md; |
| return 0; |
| } |
| |
| static struct mapped_device *dm_find_md(dev_t dev) |
| { |
| struct mapped_device *md; |
| unsigned minor = MINOR(dev); |
| |
| if (MAJOR(dev) != _major || minor >= (1 << MINORBITS)) |
| return NULL; |
| |
| spin_lock(&_minor_lock); |
| |
| md = idr_find(&_minor_idr, minor); |
| if (md && (md == MINOR_ALLOCED || |
| (MINOR(disk_devt(dm_disk(md))) != minor) || |
| test_bit(DMF_FREEING, &md->flags))) { |
| md = NULL; |
| goto out; |
| } |
| |
| out: |
| spin_unlock(&_minor_lock); |
| |
| return md; |
| } |
| |
| struct mapped_device *dm_get_md(dev_t dev) |
| { |
| struct mapped_device *md = dm_find_md(dev); |
| |
| if (md) |
| dm_get(md); |
| |
| return md; |
| } |
| |
| void *dm_get_mdptr(struct mapped_device *md) |
| { |
| return md->interface_ptr; |
| } |
| |
| void dm_set_mdptr(struct mapped_device *md, void *ptr) |
| { |
| md->interface_ptr = ptr; |
| } |
| |
| void dm_get(struct mapped_device *md) |
| { |
| atomic_inc(&md->holders); |
| } |
| |
| const char *dm_device_name(struct mapped_device *md) |
| { |
| return md->name; |
| } |
| EXPORT_SYMBOL_GPL(dm_device_name); |
| |
| void dm_put(struct mapped_device *md) |
| { |
| struct dm_table *map; |
| |
| BUG_ON(test_bit(DMF_FREEING, &md->flags)); |
| |
| if (atomic_dec_and_lock(&md->holders, &_minor_lock)) { |
| map = dm_get_table(md); |
| idr_replace(&_minor_idr, MINOR_ALLOCED, |
| MINOR(disk_devt(dm_disk(md)))); |
| set_bit(DMF_FREEING, &md->flags); |
| spin_unlock(&_minor_lock); |
| if (!dm_suspended(md)) { |
| dm_table_presuspend_targets(map); |
| dm_table_postsuspend_targets(map); |
| } |
| __unbind(md); |
| dm_table_put(map); |
| free_dev(md); |
| } |
| } |
| EXPORT_SYMBOL_GPL(dm_put); |
| |
| static int dm_wait_for_completion(struct mapped_device *md) |
| { |
| int r = 0; |
| |
| while (1) { |
| set_current_state(TASK_INTERRUPTIBLE); |
| |
| smp_mb(); |
| if (!atomic_read(&md->pending)) |
| break; |
| |
| if (signal_pending(current)) { |
| r = -EINTR; |
| break; |
| } |
| |
| io_schedule(); |
| } |
| set_current_state(TASK_RUNNING); |
| |
| return r; |
| } |
| |
| /* |
| * Process the deferred bios |
| */ |
| static void __flush_deferred_io(struct mapped_device *md) |
| { |
| struct bio *c; |
| |
| while ((c = bio_list_pop(&md->deferred))) { |
| if (__split_bio(md, c)) |
| bio_io_error(c); |
| } |
| |
| clear_bit(DMF_BLOCK_IO, &md->flags); |
| } |
| |
| static void __merge_pushback_list(struct mapped_device *md) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&md->pushback_lock, flags); |
| clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); |
| bio_list_merge_head(&md->deferred, &md->pushback); |
| bio_list_init(&md->pushback); |
| spin_unlock_irqrestore(&md->pushback_lock, flags); |
| } |
| |
| static void dm_wq_work(struct work_struct *work) |
| { |
| struct dm_wq_req *req = container_of(work, struct dm_wq_req, work); |
| struct mapped_device *md = req->md; |
| |
| down_write(&md->io_lock); |
| switch (req->type) { |
| case DM_WQ_FLUSH_ALL: |
| __merge_pushback_list(md); |
| /* pass through */ |
| case DM_WQ_FLUSH_DEFERRED: |
| __flush_deferred_io(md); |
| break; |
| default: |
| DMERR("dm_wq_work: unrecognised work type %d", req->type); |
| BUG(); |
| } |
| up_write(&md->io_lock); |
| } |
| |
| static void dm_wq_queue(struct mapped_device *md, int type, void *context, |
| struct dm_wq_req *req) |
| { |
| req->type = type; |
| req->md = md; |
| req->context = context; |
| INIT_WORK(&req->work, dm_wq_work); |
| queue_work(md->wq, &req->work); |
| } |
| |
| static void dm_queue_flush(struct mapped_device *md, int type, void *context) |
| { |
| struct dm_wq_req req; |
| |
| dm_wq_queue(md, type, context, &req); |
| flush_workqueue(md->wq); |
| } |
| |
| /* |
| * Swap in a new table (destroying old one). |
| */ |
| int dm_swap_table(struct mapped_device *md, struct dm_table *table) |
| { |
| int r = -EINVAL; |
| |
| mutex_lock(&md->suspend_lock); |
| |
| /* device must be suspended */ |
| if (!dm_suspended(md)) |
| goto out; |
| |
| /* without bdev, the device size cannot be changed */ |
| if (!md->suspended_bdev) |
| if (get_capacity(md->disk) != dm_table_get_size(table)) |
| goto out; |
| |
| __unbind(md); |
| r = __bind(md, table); |
| |
| out: |
| mutex_unlock(&md->suspend_lock); |
| return r; |
| } |
| |
| /* |
| * Functions to lock and unlock any filesystem running on the |
| * device. |
| */ |
| static int lock_fs(struct mapped_device *md) |
| { |
| int r; |
| |
| WARN_ON(md->frozen_sb); |
| |
| md->frozen_sb = freeze_bdev(md->suspended_bdev); |
| if (IS_ERR(md->frozen_sb)) { |
| r = PTR_ERR(md->frozen_sb); |
| md->frozen_sb = NULL; |
| return r; |
| } |
| |
| set_bit(DMF_FROZEN, &md->flags); |
| |
| /* don't bdput right now, we don't want the bdev |
| * to go away while it is locked. |
| */ |
| return 0; |
| } |
| |
| static void unlock_fs(struct mapped_device *md) |
| { |
| if (!test_bit(DMF_FROZEN, &md->flags)) |
| return; |
| |
| thaw_bdev(md->suspended_bdev, md->frozen_sb); |
| md->frozen_sb = NULL; |
| clear_bit(DMF_FROZEN, &md->flags); |
| } |
| |
| /* |
| * We need to be able to change a mapping table under a mounted |
| * filesystem. For example we might want to move some data in |
| * the background. Before the table can be swapped with |
| * dm_bind_table, dm_suspend must be called to flush any in |
| * flight bios and ensure that any further io gets deferred. |
| */ |
| int dm_suspend(struct mapped_device *md, unsigned suspend_flags) |
| { |
| struct dm_table *map = NULL; |
| DECLARE_WAITQUEUE(wait, current); |
| int r = 0; |
| int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0; |
| int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0; |
| |
| mutex_lock(&md->suspend_lock); |
| |
| if (dm_suspended(md)) { |
| r = -EINVAL; |
| goto out_unlock; |
| } |
| |
| map = dm_get_table(md); |
| |
| /* |
| * DMF_NOFLUSH_SUSPENDING must be set before presuspend. |
| * This flag is cleared before dm_suspend returns. |
| */ |
| if (noflush) |
| set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags); |
| |
| /* This does not get reverted if there's an error later. */ |
| dm_table_presuspend_targets(map); |
| |
| /* bdget() can stall if the pending I/Os are not flushed */ |
| if (!noflush) { |
| md->suspended_bdev = bdget_disk(md->disk, 0); |
| if (!md->suspended_bdev) { |
| DMWARN("bdget failed in dm_suspend"); |
| r = -ENOMEM; |
| goto flush_and_out; |
| } |
| |
| /* |
| * Flush I/O to the device. noflush supersedes do_lockfs, |
| * because lock_fs() needs to flush I/Os. |
| */ |
| if (do_lockfs) { |
| r = lock_fs(md); |
| if (r) |
| goto out; |
| } |
| } |
| |
| /* |
| * First we set the BLOCK_IO flag so no more ios will be mapped. |
| */ |
| down_write(&md->io_lock); |
| set_bit(DMF_BLOCK_IO, &md->flags); |
| |
| add_wait_queue(&md->wait, &wait); |
| up_write(&md->io_lock); |
| |
| /* unplug */ |
| if (map) |
| dm_table_unplug_all(map); |
| |
| /* |
| * Wait for the already-mapped ios to complete. |
| */ |
| r = dm_wait_for_completion(md); |
| |
| down_write(&md->io_lock); |
| remove_wait_queue(&md->wait, &wait); |
| |
| if (noflush) |
| __merge_pushback_list(md); |
| up_write(&md->io_lock); |
| |
| /* were we interrupted ? */ |
| if (r < 0) { |
| dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL); |
| |
| unlock_fs(md); |
| goto out; /* pushback list is already flushed, so skip flush */ |
| } |
| |
| dm_table_postsuspend_targets(map); |
| |
| set_bit(DMF_SUSPENDED, &md->flags); |
| |
| flush_and_out: |
| if (r && noflush) |
| /* |
| * Because there may be already I/Os in the pushback list, |
| * flush them before return. |
| */ |
| dm_queue_flush(md, DM_WQ_FLUSH_ALL, NULL); |
| |
| out: |
| if (r && md->suspended_bdev) { |
| bdput(md->suspended_bdev); |
| md->suspended_bdev = NULL; |
| } |
| |
| dm_table_put(map); |
| |
| out_unlock: |
| mutex_unlock(&md->suspend_lock); |
| return r; |
| } |
| |
| int dm_resume(struct mapped_device *md) |
| { |
| int r = -EINVAL; |
| struct dm_table *map = NULL; |
| |
| mutex_lock(&md->suspend_lock); |
| if (!dm_suspended(md)) |
| goto out; |
| |
| map = dm_get_table(md); |
| if (!map || !dm_table_get_size(map)) |
| goto out; |
| |
| r = dm_table_resume_targets(map); |
| if (r) |
| goto out; |
| |
| dm_queue_flush(md, DM_WQ_FLUSH_DEFERRED, NULL); |
| |
| unlock_fs(md); |
| |
| if (md->suspended_bdev) { |
| bdput(md->suspended_bdev); |
| md->suspended_bdev = NULL; |
| } |
| |
| clear_bit(DMF_SUSPENDED, &md->flags); |
| |
| dm_table_unplug_all(map); |
| |
| dm_kobject_uevent(md); |
| |
| r = 0; |
| |
| out: |
| dm_table_put(map); |
| mutex_unlock(&md->suspend_lock); |
| |
| return r; |
| } |
| |
| /*----------------------------------------------------------------- |
| * Event notification. |
| *---------------------------------------------------------------*/ |
| void dm_kobject_uevent(struct mapped_device *md) |
| { |
| kobject_uevent(&disk_to_dev(md->disk)->kobj, KOBJ_CHANGE); |
| } |
| |
| uint32_t dm_next_uevent_seq(struct mapped_device *md) |
| { |
| return atomic_add_return(1, &md->uevent_seq); |
| } |
| |
| uint32_t dm_get_event_nr(struct mapped_device *md) |
| { |
| return atomic_read(&md->event_nr); |
| } |
| |
| int dm_wait_event(struct mapped_device *md, int event_nr) |
| { |
| return wait_event_interruptible(md->eventq, |
| (event_nr != atomic_read(&md->event_nr))); |
| } |
| |
| void dm_uevent_add(struct mapped_device *md, struct list_head *elist) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&md->uevent_lock, flags); |
| list_add(elist, &md->uevent_list); |
| spin_unlock_irqrestore(&md->uevent_lock, flags); |
| } |
| |
| /* |
| * The gendisk is only valid as long as you have a reference |
| * count on 'md'. |
| */ |
| struct gendisk *dm_disk(struct mapped_device *md) |
| { |
| return md->disk; |
| } |
| |
| int dm_suspended(struct mapped_device *md) |
| { |
| return test_bit(DMF_SUSPENDED, &md->flags); |
| } |
| |
| int dm_noflush_suspending(struct dm_target *ti) |
| { |
| struct mapped_device *md = dm_table_get_md(ti->table); |
| int r = __noflush_suspending(md); |
| |
| dm_put(md); |
| |
| return r; |
| } |
| EXPORT_SYMBOL_GPL(dm_noflush_suspending); |
| |
| static struct block_device_operations dm_blk_dops = { |
| .open = dm_blk_open, |
| .release = dm_blk_close, |
| .ioctl = dm_blk_ioctl, |
| .getgeo = dm_blk_getgeo, |
| .owner = THIS_MODULE |
| }; |
| |
| EXPORT_SYMBOL(dm_get_mapinfo); |
| |
| /* |
| * module hooks |
| */ |
| module_init(dm_init); |
| module_exit(dm_exit); |
| |
| module_param(major, uint, 0); |
| MODULE_PARM_DESC(major, "The major number of the device mapper"); |
| MODULE_DESCRIPTION(DM_NAME " driver"); |
| MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>"); |
| MODULE_LICENSE("GPL"); |