2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
9 #include "dm-bio-list.h"
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/moduleparam.h>
14 #include <linux/blkpg.h>
15 #include <linux/bio.h>
16 #include <linux/buffer_head.h>
17 #include <linux/mempool.h>
18 #include <linux/slab.h>
19 #include <linux/idr.h>
21 static const char *_name
= DM_NAME
;
23 static unsigned int major
= 0;
24 static unsigned int _major
= 0;
27 * One of these is allocated per bio.
30 struct mapped_device
*md
;
34 unsigned long start_time
;
38 * One of these is allocated per target within a bio. Hopefully
39 * this will be simplified out one day.
47 union map_info
*dm_get_mapinfo(struct bio
*bio
)
49 if (bio
&& bio
->bi_private
)
50 return &((struct target_io
*)bio
->bi_private
)->info
;
55 * Bits for the md->flags field.
57 #define DMF_BLOCK_IO 0
58 #define DMF_SUSPENDED 1
61 struct mapped_device
{
62 struct rw_semaphore io_lock
;
63 struct semaphore suspend_lock
;
69 request_queue_t
*queue
;
75 * A list of ios that arrived while we were suspended.
78 wait_queue_head_t wait
;
79 struct bio_list deferred
;
82 * The current mapping.
87 * io objects are allocated from here.
96 wait_queue_head_t eventq
;
99 * freeze/thaw support require holding onto a super block
101 struct super_block
*frozen_sb
;
102 struct block_device
*suspended_bdev
;
106 static kmem_cache_t
*_io_cache
;
107 static kmem_cache_t
*_tio_cache
;
109 static struct bio_set
*dm_set
;
111 static int __init
local_init(void)
115 dm_set
= bioset_create(16, 16, 4);
119 /* allocate a slab for the dm_ios */
120 _io_cache
= kmem_cache_create("dm_io",
121 sizeof(struct dm_io
), 0, 0, NULL
, NULL
);
125 /* allocate a slab for the target ios */
126 _tio_cache
= kmem_cache_create("dm_tio", sizeof(struct target_io
),
129 kmem_cache_destroy(_io_cache
);
134 r
= register_blkdev(_major
, _name
);
136 kmem_cache_destroy(_tio_cache
);
137 kmem_cache_destroy(_io_cache
);
147 static void local_exit(void)
149 kmem_cache_destroy(_tio_cache
);
150 kmem_cache_destroy(_io_cache
);
154 if (unregister_blkdev(_major
, _name
) < 0)
155 DMERR("devfs_unregister_blkdev failed");
159 DMINFO("cleaned up");
162 int (*_inits
[])(void) __initdata
= {
170 void (*_exits
[])(void) = {
178 static int __init
dm_init(void)
180 const int count
= ARRAY_SIZE(_inits
);
184 for (i
= 0; i
< count
; i
++) {
199 static void __exit
dm_exit(void)
201 int i
= ARRAY_SIZE(_exits
);
208 * Block device functions
210 static int dm_blk_open(struct inode
*inode
, struct file
*file
)
212 struct mapped_device
*md
;
214 md
= inode
->i_bdev
->bd_disk
->private_data
;
219 static int dm_blk_close(struct inode
*inode
, struct file
*file
)
221 struct mapped_device
*md
;
223 md
= inode
->i_bdev
->bd_disk
->private_data
;
228 static inline struct dm_io
*alloc_io(struct mapped_device
*md
)
230 return mempool_alloc(md
->io_pool
, GFP_NOIO
);
233 static inline void free_io(struct mapped_device
*md
, struct dm_io
*io
)
235 mempool_free(io
, md
->io_pool
);
238 static inline struct target_io
*alloc_tio(struct mapped_device
*md
)
240 return mempool_alloc(md
->tio_pool
, GFP_NOIO
);
243 static inline void free_tio(struct mapped_device
*md
, struct target_io
*tio
)
245 mempool_free(tio
, md
->tio_pool
);
248 static void start_io_acct(struct dm_io
*io
)
250 struct mapped_device
*md
= io
->md
;
252 io
->start_time
= jiffies
;
255 disk_round_stats(dm_disk(md
));
257 dm_disk(md
)->in_flight
= atomic_inc_return(&md
->pending
);
260 static int end_io_acct(struct dm_io
*io
)
262 struct mapped_device
*md
= io
->md
;
263 struct bio
*bio
= io
->bio
;
264 unsigned long duration
= jiffies
- io
->start_time
;
266 int rw
= bio_data_dir(bio
);
269 disk_round_stats(dm_disk(md
));
271 dm_disk(md
)->in_flight
= pending
= atomic_dec_return(&md
->pending
);
273 disk_stat_add(dm_disk(md
), ticks
[rw
], duration
);
279 * Add the bio to the list of deferred io.
281 static int queue_io(struct mapped_device
*md
, struct bio
*bio
)
283 down_write(&md
->io_lock
);
285 if (!test_bit(DMF_BLOCK_IO
, &md
->flags
)) {
286 up_write(&md
->io_lock
);
290 bio_list_add(&md
->deferred
, bio
);
292 up_write(&md
->io_lock
);
293 return 0; /* deferred successfully */
297 * Everyone (including functions in this file), should use this
298 * function to access the md->map field, and make sure they call
299 * dm_table_put() when finished.
301 struct dm_table
*dm_get_table(struct mapped_device
*md
)
305 read_lock(&md
->map_lock
);
309 read_unlock(&md
->map_lock
);
314 /*-----------------------------------------------------------------
316 * A more elegant soln is in the works that uses the queue
317 * merge fn, unfortunately there are a couple of changes to
318 * the block layer that I want to make for this. So in the
319 * interests of getting something for people to use I give
320 * you this clearly demarcated crap.
321 *---------------------------------------------------------------*/
324 * Decrements the number of outstanding ios that a bio has been
325 * cloned into, completing the original io if necc.
327 static void dec_pending(struct dm_io
*io
, int error
)
332 if (atomic_dec_and_test(&io
->io_count
)) {
334 /* nudge anyone waiting on suspend queue */
335 wake_up(&io
->md
->wait
);
337 bio_endio(io
->bio
, io
->bio
->bi_size
, io
->error
);
342 static int clone_endio(struct bio
*bio
, unsigned int done
, int error
)
345 struct target_io
*tio
= bio
->bi_private
;
346 struct dm_io
*io
= tio
->io
;
347 dm_endio_fn endio
= tio
->ti
->type
->end_io
;
352 if (!bio_flagged(bio
, BIO_UPTODATE
) && !error
)
356 r
= endio(tio
->ti
, bio
, error
, &tio
->info
);
361 /* the target wants another shot at the io */
365 free_tio(io
->md
, tio
);
366 dec_pending(io
, error
);
371 static sector_t
max_io_len(struct mapped_device
*md
,
372 sector_t sector
, struct dm_target
*ti
)
374 sector_t offset
= sector
- ti
->begin
;
375 sector_t len
= ti
->len
- offset
;
378 * Does the target need to split even further ?
382 boundary
= ((offset
+ ti
->split_io
) & ~(ti
->split_io
- 1))
391 static void __map_bio(struct dm_target
*ti
, struct bio
*clone
,
392 struct target_io
*tio
)
399 BUG_ON(!clone
->bi_size
);
401 clone
->bi_end_io
= clone_endio
;
402 clone
->bi_private
= tio
;
405 * Map the clone. If r == 0 we don't need to do
406 * anything, the target has assumed ownership of
409 atomic_inc(&tio
->io
->io_count
);
410 r
= ti
->type
->map(ti
, clone
, &tio
->info
);
412 /* the bio has been remapped so dispatch it */
413 generic_make_request(clone
);
416 /* error the io and bail out */
417 struct dm_io
*io
= tio
->io
;
418 free_tio(tio
->io
->md
, tio
);
425 struct mapped_device
*md
;
426 struct dm_table
*map
;
430 sector_t sector_count
;
434 static void dm_bio_destructor(struct bio
*bio
)
436 bio_free(bio
, dm_set
);
440 * Creates a little bio that is just does part of a bvec.
442 static struct bio
*split_bvec(struct bio
*bio
, sector_t sector
,
443 unsigned short idx
, unsigned int offset
,
447 struct bio_vec
*bv
= bio
->bi_io_vec
+ idx
;
449 clone
= bio_alloc_bioset(GFP_NOIO
, 1, dm_set
);
450 clone
->bi_destructor
= dm_bio_destructor
;
451 *clone
->bi_io_vec
= *bv
;
453 clone
->bi_sector
= sector
;
454 clone
->bi_bdev
= bio
->bi_bdev
;
455 clone
->bi_rw
= bio
->bi_rw
;
457 clone
->bi_size
= to_bytes(len
);
458 clone
->bi_io_vec
->bv_offset
= offset
;
459 clone
->bi_io_vec
->bv_len
= clone
->bi_size
;
465 * Creates a bio that consists of range of complete bvecs.
467 static struct bio
*clone_bio(struct bio
*bio
, sector_t sector
,
468 unsigned short idx
, unsigned short bv_count
,
473 clone
= bio_clone(bio
, GFP_NOIO
);
474 clone
->bi_sector
= sector
;
476 clone
->bi_vcnt
= idx
+ bv_count
;
477 clone
->bi_size
= to_bytes(len
);
478 clone
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
483 static void __clone_and_map(struct clone_info
*ci
)
485 struct bio
*clone
, *bio
= ci
->bio
;
486 struct dm_target
*ti
= dm_table_find_target(ci
->map
, ci
->sector
);
487 sector_t len
= 0, max
= max_io_len(ci
->md
, ci
->sector
, ti
);
488 struct target_io
*tio
;
491 * Allocate a target io object.
493 tio
= alloc_tio(ci
->md
);
496 memset(&tio
->info
, 0, sizeof(tio
->info
));
498 if (ci
->sector_count
<= max
) {
500 * Optimise for the simple case where we can do all of
501 * the remaining io with a single clone.
503 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
,
504 bio
->bi_vcnt
- ci
->idx
, ci
->sector_count
);
505 __map_bio(ti
, clone
, tio
);
506 ci
->sector_count
= 0;
508 } else if (to_sector(bio
->bi_io_vec
[ci
->idx
].bv_len
) <= max
) {
510 * There are some bvecs that don't span targets.
511 * Do as many of these as possible.
514 sector_t remaining
= max
;
517 for (i
= ci
->idx
; remaining
&& (i
< bio
->bi_vcnt
); i
++) {
518 bv_len
= to_sector(bio
->bi_io_vec
[i
].bv_len
);
520 if (bv_len
> remaining
)
527 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
, i
- ci
->idx
, len
);
528 __map_bio(ti
, clone
, tio
);
531 ci
->sector_count
-= len
;
536 * Create two copy bios to deal with io that has
537 * been split across a target.
539 struct bio_vec
*bv
= bio
->bi_io_vec
+ ci
->idx
;
541 clone
= split_bvec(bio
, ci
->sector
, ci
->idx
,
543 __map_bio(ti
, clone
, tio
);
546 ci
->sector_count
-= max
;
547 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
549 len
= to_sector(bv
->bv_len
) - max
;
550 clone
= split_bvec(bio
, ci
->sector
, ci
->idx
,
551 bv
->bv_offset
+ to_bytes(max
), len
);
552 tio
= alloc_tio(ci
->md
);
555 memset(&tio
->info
, 0, sizeof(tio
->info
));
556 __map_bio(ti
, clone
, tio
);
559 ci
->sector_count
-= len
;
565 * Split the bio into several clones.
567 static void __split_bio(struct mapped_device
*md
, struct bio
*bio
)
569 struct clone_info ci
;
571 ci
.map
= dm_get_table(md
);
573 bio_io_error(bio
, bio
->bi_size
);
579 ci
.io
= alloc_io(md
);
581 atomic_set(&ci
.io
->io_count
, 1);
584 ci
.sector
= bio
->bi_sector
;
585 ci
.sector_count
= bio_sectors(bio
);
586 ci
.idx
= bio
->bi_idx
;
588 start_io_acct(ci
.io
);
589 while (ci
.sector_count
)
590 __clone_and_map(&ci
);
592 /* drop the extra reference count */
593 dec_pending(ci
.io
, 0);
594 dm_table_put(ci
.map
);
596 /*-----------------------------------------------------------------
598 *---------------------------------------------------------------*/
601 * The request function that just remaps the bio built up by
604 static int dm_request(request_queue_t
*q
, struct bio
*bio
)
607 int rw
= bio_data_dir(bio
);
608 struct mapped_device
*md
= q
->queuedata
;
610 down_read(&md
->io_lock
);
612 disk_stat_inc(dm_disk(md
), ios
[rw
]);
613 disk_stat_add(dm_disk(md
), sectors
[rw
], bio_sectors(bio
));
616 * If we're suspended we have to queue
619 while (test_bit(DMF_BLOCK_IO
, &md
->flags
)) {
620 up_read(&md
->io_lock
);
622 if (bio_rw(bio
) == READA
) {
623 bio_io_error(bio
, bio
->bi_size
);
627 r
= queue_io(md
, bio
);
629 bio_io_error(bio
, bio
->bi_size
);
633 return 0; /* deferred successfully */
636 * We're in a while loop, because someone could suspend
637 * before we get to the following read lock.
639 down_read(&md
->io_lock
);
642 __split_bio(md
, bio
);
643 up_read(&md
->io_lock
);
647 static int dm_flush_all(request_queue_t
*q
, struct gendisk
*disk
,
648 sector_t
*error_sector
)
650 struct mapped_device
*md
= q
->queuedata
;
651 struct dm_table
*map
= dm_get_table(md
);
655 ret
= dm_table_flush_all(map
);
662 static void dm_unplug_all(request_queue_t
*q
)
664 struct mapped_device
*md
= q
->queuedata
;
665 struct dm_table
*map
= dm_get_table(md
);
668 dm_table_unplug_all(map
);
673 static int dm_any_congested(void *congested_data
, int bdi_bits
)
676 struct mapped_device
*md
= (struct mapped_device
*) congested_data
;
677 struct dm_table
*map
= dm_get_table(md
);
679 if (!map
|| test_bit(DMF_BLOCK_IO
, &md
->flags
))
682 r
= dm_table_any_congested(map
, bdi_bits
);
688 /*-----------------------------------------------------------------
689 * An IDR is used to keep track of allocated minor numbers.
690 *---------------------------------------------------------------*/
691 static DECLARE_MUTEX(_minor_lock
);
692 static DEFINE_IDR(_minor_idr
);
694 static void free_minor(unsigned int minor
)
697 idr_remove(&_minor_idr
, minor
);
702 * See if the device with a specific minor # is free.
704 static int specific_minor(struct mapped_device
*md
, unsigned int minor
)
708 if (minor
>= (1 << MINORBITS
))
713 if (idr_find(&_minor_idr
, minor
)) {
718 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
724 r
= idr_get_new_above(&_minor_idr
, md
, minor
, &m
);
730 idr_remove(&_minor_idr
, m
);
740 static int next_free_minor(struct mapped_device
*md
, unsigned int *minor
)
747 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
753 r
= idr_get_new(&_minor_idr
, md
, &m
);
758 if (m
>= (1 << MINORBITS
)) {
759 idr_remove(&_minor_idr
, m
);
771 static struct block_device_operations dm_blk_dops
;
774 * Allocate and initialise a blank device with a given minor.
776 static struct mapped_device
*alloc_dev(unsigned int minor
, int persistent
)
779 struct mapped_device
*md
= kmalloc(sizeof(*md
), GFP_KERNEL
);
782 DMWARN("unable to allocate device, out of memory.");
786 /* get a minor number for the dev */
787 r
= persistent
? specific_minor(md
, minor
) : next_free_minor(md
, &minor
);
791 memset(md
, 0, sizeof(*md
));
792 init_rwsem(&md
->io_lock
);
793 init_MUTEX(&md
->suspend_lock
);
794 rwlock_init(&md
->map_lock
);
795 atomic_set(&md
->holders
, 1);
796 atomic_set(&md
->event_nr
, 0);
798 md
->queue
= blk_alloc_queue(GFP_KERNEL
);
802 md
->queue
->queuedata
= md
;
803 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
804 md
->queue
->backing_dev_info
.congested_data
= md
;
805 blk_queue_make_request(md
->queue
, dm_request
);
806 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
807 md
->queue
->unplug_fn
= dm_unplug_all
;
808 md
->queue
->issue_flush_fn
= dm_flush_all
;
810 md
->io_pool
= mempool_create(MIN_IOS
, mempool_alloc_slab
,
811 mempool_free_slab
, _io_cache
);
815 md
->tio_pool
= mempool_create(MIN_IOS
, mempool_alloc_slab
,
816 mempool_free_slab
, _tio_cache
);
820 md
->disk
= alloc_disk(1);
824 md
->disk
->major
= _major
;
825 md
->disk
->first_minor
= minor
;
826 md
->disk
->fops
= &dm_blk_dops
;
827 md
->disk
->queue
= md
->queue
;
828 md
->disk
->private_data
= md
;
829 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
832 atomic_set(&md
->pending
, 0);
833 init_waitqueue_head(&md
->wait
);
834 init_waitqueue_head(&md
->eventq
);
839 mempool_destroy(md
->tio_pool
);
841 mempool_destroy(md
->io_pool
);
843 blk_put_queue(md
->queue
);
850 static void free_dev(struct mapped_device
*md
)
852 free_minor(md
->disk
->first_minor
);
853 mempool_destroy(md
->tio_pool
);
854 mempool_destroy(md
->io_pool
);
855 del_gendisk(md
->disk
);
857 blk_put_queue(md
->queue
);
862 * Bind a table to the device.
864 static void event_callback(void *context
)
866 struct mapped_device
*md
= (struct mapped_device
*) context
;
868 atomic_inc(&md
->event_nr
);
869 wake_up(&md
->eventq
);
872 static void __set_size(struct mapped_device
*md
, sector_t size
)
874 set_capacity(md
->disk
, size
);
876 mutex_lock(&md
->suspended_bdev
->bd_inode
->i_mutex
);
877 i_size_write(md
->suspended_bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
878 mutex_unlock(&md
->suspended_bdev
->bd_inode
->i_mutex
);
881 static int __bind(struct mapped_device
*md
, struct dm_table
*t
)
883 request_queue_t
*q
= md
->queue
;
886 size
= dm_table_get_size(t
);
887 __set_size(md
, size
);
892 dm_table_event_callback(t
, event_callback
, md
);
894 write_lock(&md
->map_lock
);
896 dm_table_set_restrictions(t
, q
);
897 write_unlock(&md
->map_lock
);
902 static void __unbind(struct mapped_device
*md
)
904 struct dm_table
*map
= md
->map
;
909 dm_table_event_callback(map
, NULL
, NULL
);
910 write_lock(&md
->map_lock
);
912 write_unlock(&md
->map_lock
);
917 * Constructor for a new device.
919 static int create_aux(unsigned int minor
, int persistent
,
920 struct mapped_device
**result
)
922 struct mapped_device
*md
;
924 md
= alloc_dev(minor
, persistent
);
932 int dm_create(struct mapped_device
**result
)
934 return create_aux(0, 0, result
);
937 int dm_create_with_minor(unsigned int minor
, struct mapped_device
**result
)
939 return create_aux(minor
, 1, result
);
942 static struct mapped_device
*dm_find_md(dev_t dev
)
944 struct mapped_device
*md
;
945 unsigned minor
= MINOR(dev
);
947 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
952 md
= idr_find(&_minor_idr
, minor
);
953 if (!md
|| (dm_disk(md
)->first_minor
!= minor
))
961 struct mapped_device
*dm_get_md(dev_t dev
)
963 struct mapped_device
*md
= dm_find_md(dev
);
971 void *dm_get_mdptr(dev_t dev
)
973 struct mapped_device
*md
;
976 md
= dm_find_md(dev
);
978 mdptr
= md
->interface_ptr
;
982 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
984 md
->interface_ptr
= ptr
;
987 void dm_get(struct mapped_device
*md
)
989 atomic_inc(&md
->holders
);
992 void dm_put(struct mapped_device
*md
)
994 struct dm_table
*map
= dm_get_table(md
);
996 if (atomic_dec_and_test(&md
->holders
)) {
997 if (!dm_suspended(md
)) {
998 dm_table_presuspend_targets(map
);
999 dm_table_postsuspend_targets(map
);
1009 * Process the deferred bios
1011 static void __flush_deferred_io(struct mapped_device
*md
, struct bio
*c
)
1024 * Swap in a new table (destroying old one).
1026 int dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
1030 down(&md
->suspend_lock
);
1032 /* device must be suspended */
1033 if (!dm_suspended(md
))
1037 r
= __bind(md
, table
);
1040 up(&md
->suspend_lock
);
1045 * Functions to lock and unlock any filesystem running on the
1048 static int lock_fs(struct mapped_device
*md
)
1052 WARN_ON(md
->frozen_sb
);
1054 md
->frozen_sb
= freeze_bdev(md
->suspended_bdev
);
1055 if (IS_ERR(md
->frozen_sb
)) {
1056 r
= PTR_ERR(md
->frozen_sb
);
1057 md
->frozen_sb
= NULL
;
1061 set_bit(DMF_FROZEN
, &md
->flags
);
1063 /* don't bdput right now, we don't want the bdev
1064 * to go away while it is locked.
1069 static void unlock_fs(struct mapped_device
*md
)
1071 if (!test_bit(DMF_FROZEN
, &md
->flags
))
1074 thaw_bdev(md
->suspended_bdev
, md
->frozen_sb
);
1075 md
->frozen_sb
= NULL
;
1076 clear_bit(DMF_FROZEN
, &md
->flags
);
1080 * We need to be able to change a mapping table under a mounted
1081 * filesystem. For example we might want to move some data in
1082 * the background. Before the table can be swapped with
1083 * dm_bind_table, dm_suspend must be called to flush any in
1084 * flight bios and ensure that any further io gets deferred.
1086 int dm_suspend(struct mapped_device
*md
, int do_lockfs
)
1088 struct dm_table
*map
= NULL
;
1089 DECLARE_WAITQUEUE(wait
, current
);
1092 down(&md
->suspend_lock
);
1094 if (dm_suspended(md
))
1097 map
= dm_get_table(md
);
1099 /* This does not get reverted if there's an error later. */
1100 dm_table_presuspend_targets(map
);
1102 md
->suspended_bdev
= bdget_disk(md
->disk
, 0);
1103 if (!md
->suspended_bdev
) {
1104 DMWARN("bdget failed in dm_suspend");
1109 /* Flush I/O to the device. */
1117 * First we set the BLOCK_IO flag so no more ios will be mapped.
1119 down_write(&md
->io_lock
);
1120 set_bit(DMF_BLOCK_IO
, &md
->flags
);
1122 add_wait_queue(&md
->wait
, &wait
);
1123 up_write(&md
->io_lock
);
1127 dm_table_unplug_all(map
);
1130 * Then we wait for the already mapped ios to
1134 set_current_state(TASK_INTERRUPTIBLE
);
1136 if (!atomic_read(&md
->pending
) || signal_pending(current
))
1141 set_current_state(TASK_RUNNING
);
1143 down_write(&md
->io_lock
);
1144 remove_wait_queue(&md
->wait
, &wait
);
1146 /* were we interrupted ? */
1148 if (atomic_read(&md
->pending
)) {
1149 up_write(&md
->io_lock
);
1151 clear_bit(DMF_BLOCK_IO
, &md
->flags
);
1154 up_write(&md
->io_lock
);
1156 dm_table_postsuspend_targets(map
);
1158 set_bit(DMF_SUSPENDED
, &md
->flags
);
1163 if (r
&& md
->suspended_bdev
) {
1164 bdput(md
->suspended_bdev
);
1165 md
->suspended_bdev
= NULL
;
1169 up(&md
->suspend_lock
);
1173 int dm_resume(struct mapped_device
*md
)
1177 struct dm_table
*map
= NULL
;
1179 down(&md
->suspend_lock
);
1180 if (!dm_suspended(md
))
1183 map
= dm_get_table(md
);
1184 if (!map
|| !dm_table_get_size(map
))
1187 dm_table_resume_targets(map
);
1189 down_write(&md
->io_lock
);
1190 clear_bit(DMF_BLOCK_IO
, &md
->flags
);
1192 def
= bio_list_get(&md
->deferred
);
1193 __flush_deferred_io(md
, def
);
1194 up_write(&md
->io_lock
);
1198 bdput(md
->suspended_bdev
);
1199 md
->suspended_bdev
= NULL
;
1201 clear_bit(DMF_SUSPENDED
, &md
->flags
);
1203 dm_table_unplug_all(map
);
1209 up(&md
->suspend_lock
);
1214 /*-----------------------------------------------------------------
1215 * Event notification.
1216 *---------------------------------------------------------------*/
1217 uint32_t dm_get_event_nr(struct mapped_device
*md
)
1219 return atomic_read(&md
->event_nr
);
1222 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
1224 return wait_event_interruptible(md
->eventq
,
1225 (event_nr
!= atomic_read(&md
->event_nr
)));
1229 * The gendisk is only valid as long as you have a reference
1232 struct gendisk
*dm_disk(struct mapped_device
*md
)
1237 int dm_suspended(struct mapped_device
*md
)
1239 return test_bit(DMF_SUSPENDED
, &md
->flags
);
1242 static struct block_device_operations dm_blk_dops
= {
1243 .open
= dm_blk_open
,
1244 .release
= dm_blk_close
,
1245 .owner
= THIS_MODULE
1248 EXPORT_SYMBOL(dm_get_mapinfo
);
1253 module_init(dm_init
);
1254 module_exit(dm_exit
);
1256 module_param(major
, uint
, 0);
1257 MODULE_PARM_DESC(major
, "The major number of the device mapper");
1258 MODULE_DESCRIPTION(DM_NAME
" driver");
1259 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
1260 MODULE_LICENSE("GPL");