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>
20 #include <linux/blktrace_api.h>
22 static const char *_name
= DM_NAME
;
24 static unsigned int major
= 0;
25 static unsigned int _major
= 0;
28 * One of these is allocated per bio.
31 struct mapped_device
*md
;
35 unsigned long start_time
;
39 * One of these is allocated per target within a bio. Hopefully
40 * this will be simplified out one day.
48 union map_info
*dm_get_mapinfo(struct bio
*bio
)
50 if (bio
&& bio
->bi_private
)
51 return &((struct target_io
*)bio
->bi_private
)->info
;
56 * Bits for the md->flags field.
58 #define DMF_BLOCK_IO 0
59 #define DMF_SUSPENDED 1
62 struct mapped_device
{
63 struct rw_semaphore io_lock
;
64 struct semaphore suspend_lock
;
70 request_queue_t
*queue
;
76 * A list of ios that arrived while we were suspended.
79 wait_queue_head_t wait
;
80 struct bio_list deferred
;
83 * The current mapping.
88 * io objects are allocated from here.
97 wait_queue_head_t eventq
;
100 * freeze/thaw support require holding onto a super block
102 struct super_block
*frozen_sb
;
103 struct block_device
*suspended_bdev
;
107 static kmem_cache_t
*_io_cache
;
108 static kmem_cache_t
*_tio_cache
;
110 static struct bio_set
*dm_set
;
112 static int __init
local_init(void)
116 dm_set
= bioset_create(16, 16, 4);
120 /* allocate a slab for the dm_ios */
121 _io_cache
= kmem_cache_create("dm_io",
122 sizeof(struct dm_io
), 0, 0, NULL
, NULL
);
126 /* allocate a slab for the target ios */
127 _tio_cache
= kmem_cache_create("dm_tio", sizeof(struct target_io
),
130 kmem_cache_destroy(_io_cache
);
135 r
= register_blkdev(_major
, _name
);
137 kmem_cache_destroy(_tio_cache
);
138 kmem_cache_destroy(_io_cache
);
148 static void local_exit(void)
150 kmem_cache_destroy(_tio_cache
);
151 kmem_cache_destroy(_io_cache
);
155 if (unregister_blkdev(_major
, _name
) < 0)
156 DMERR("devfs_unregister_blkdev failed");
160 DMINFO("cleaned up");
163 int (*_inits
[])(void) __initdata
= {
171 void (*_exits
[])(void) = {
179 static int __init
dm_init(void)
181 const int count
= ARRAY_SIZE(_inits
);
185 for (i
= 0; i
< count
; i
++) {
200 static void __exit
dm_exit(void)
202 int i
= ARRAY_SIZE(_exits
);
209 * Block device functions
211 static int dm_blk_open(struct inode
*inode
, struct file
*file
)
213 struct mapped_device
*md
;
215 md
= inode
->i_bdev
->bd_disk
->private_data
;
220 static int dm_blk_close(struct inode
*inode
, struct file
*file
)
222 struct mapped_device
*md
;
224 md
= inode
->i_bdev
->bd_disk
->private_data
;
229 static inline struct dm_io
*alloc_io(struct mapped_device
*md
)
231 return mempool_alloc(md
->io_pool
, GFP_NOIO
);
234 static inline void free_io(struct mapped_device
*md
, struct dm_io
*io
)
236 mempool_free(io
, md
->io_pool
);
239 static inline struct target_io
*alloc_tio(struct mapped_device
*md
)
241 return mempool_alloc(md
->tio_pool
, GFP_NOIO
);
244 static inline void free_tio(struct mapped_device
*md
, struct target_io
*tio
)
246 mempool_free(tio
, md
->tio_pool
);
249 static void start_io_acct(struct dm_io
*io
)
251 struct mapped_device
*md
= io
->md
;
253 io
->start_time
= jiffies
;
256 disk_round_stats(dm_disk(md
));
258 dm_disk(md
)->in_flight
= atomic_inc_return(&md
->pending
);
261 static int end_io_acct(struct dm_io
*io
)
263 struct mapped_device
*md
= io
->md
;
264 struct bio
*bio
= io
->bio
;
265 unsigned long duration
= jiffies
- io
->start_time
;
267 int rw
= bio_data_dir(bio
);
270 disk_round_stats(dm_disk(md
));
272 dm_disk(md
)->in_flight
= pending
= atomic_dec_return(&md
->pending
);
274 disk_stat_add(dm_disk(md
), ticks
[rw
], duration
);
280 * Add the bio to the list of deferred io.
282 static int queue_io(struct mapped_device
*md
, struct bio
*bio
)
284 down_write(&md
->io_lock
);
286 if (!test_bit(DMF_BLOCK_IO
, &md
->flags
)) {
287 up_write(&md
->io_lock
);
291 bio_list_add(&md
->deferred
, bio
);
293 up_write(&md
->io_lock
);
294 return 0; /* deferred successfully */
298 * Everyone (including functions in this file), should use this
299 * function to access the md->map field, and make sure they call
300 * dm_table_put() when finished.
302 struct dm_table
*dm_get_table(struct mapped_device
*md
)
306 read_lock(&md
->map_lock
);
310 read_unlock(&md
->map_lock
);
315 /*-----------------------------------------------------------------
317 * A more elegant soln is in the works that uses the queue
318 * merge fn, unfortunately there are a couple of changes to
319 * the block layer that I want to make for this. So in the
320 * interests of getting something for people to use I give
321 * you this clearly demarcated crap.
322 *---------------------------------------------------------------*/
325 * Decrements the number of outstanding ios that a bio has been
326 * cloned into, completing the original io if necc.
328 static void dec_pending(struct dm_io
*io
, int error
)
333 if (atomic_dec_and_test(&io
->io_count
)) {
335 /* nudge anyone waiting on suspend queue */
336 wake_up(&io
->md
->wait
);
338 blk_add_trace_bio(io
->md
->queue
, io
->bio
, BLK_TA_COMPLETE
);
340 bio_endio(io
->bio
, io
->bio
->bi_size
, io
->error
);
345 static int clone_endio(struct bio
*bio
, unsigned int done
, int error
)
348 struct target_io
*tio
= bio
->bi_private
;
349 struct dm_io
*io
= tio
->io
;
350 dm_endio_fn endio
= tio
->ti
->type
->end_io
;
355 if (!bio_flagged(bio
, BIO_UPTODATE
) && !error
)
359 r
= endio(tio
->ti
, bio
, error
, &tio
->info
);
364 /* the target wants another shot at the io */
368 free_tio(io
->md
, tio
);
369 dec_pending(io
, error
);
374 static sector_t
max_io_len(struct mapped_device
*md
,
375 sector_t sector
, struct dm_target
*ti
)
377 sector_t offset
= sector
- ti
->begin
;
378 sector_t len
= ti
->len
- offset
;
381 * Does the target need to split even further ?
385 boundary
= ((offset
+ ti
->split_io
) & ~(ti
->split_io
- 1))
394 static void __map_bio(struct dm_target
*ti
, struct bio
*clone
,
395 struct target_io
*tio
)
403 BUG_ON(!clone
->bi_size
);
405 clone
->bi_end_io
= clone_endio
;
406 clone
->bi_private
= tio
;
409 * Map the clone. If r == 0 we don't need to do
410 * anything, the target has assumed ownership of
413 atomic_inc(&tio
->io
->io_count
);
414 sector
= clone
->bi_sector
;
415 r
= ti
->type
->map(ti
, clone
, &tio
->info
);
417 /* the bio has been remapped so dispatch it */
419 blk_add_trace_remap(bdev_get_queue(clone
->bi_bdev
), clone
,
420 tio
->io
->bio
->bi_bdev
->bd_dev
, sector
,
423 generic_make_request(clone
);
427 /* error the io and bail out */
428 struct dm_io
*io
= tio
->io
;
429 free_tio(tio
->io
->md
, tio
);
436 struct mapped_device
*md
;
437 struct dm_table
*map
;
441 sector_t sector_count
;
445 static void dm_bio_destructor(struct bio
*bio
)
447 bio_free(bio
, dm_set
);
451 * Creates a little bio that is just does part of a bvec.
453 static struct bio
*split_bvec(struct bio
*bio
, sector_t sector
,
454 unsigned short idx
, unsigned int offset
,
458 struct bio_vec
*bv
= bio
->bi_io_vec
+ idx
;
460 clone
= bio_alloc_bioset(GFP_NOIO
, 1, dm_set
);
461 clone
->bi_destructor
= dm_bio_destructor
;
462 *clone
->bi_io_vec
= *bv
;
464 clone
->bi_sector
= sector
;
465 clone
->bi_bdev
= bio
->bi_bdev
;
466 clone
->bi_rw
= bio
->bi_rw
;
468 clone
->bi_size
= to_bytes(len
);
469 clone
->bi_io_vec
->bv_offset
= offset
;
470 clone
->bi_io_vec
->bv_len
= clone
->bi_size
;
476 * Creates a bio that consists of range of complete bvecs.
478 static struct bio
*clone_bio(struct bio
*bio
, sector_t sector
,
479 unsigned short idx
, unsigned short bv_count
,
484 clone
= bio_clone(bio
, GFP_NOIO
);
485 clone
->bi_sector
= sector
;
487 clone
->bi_vcnt
= idx
+ bv_count
;
488 clone
->bi_size
= to_bytes(len
);
489 clone
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
494 static void __clone_and_map(struct clone_info
*ci
)
496 struct bio
*clone
, *bio
= ci
->bio
;
497 struct dm_target
*ti
= dm_table_find_target(ci
->map
, ci
->sector
);
498 sector_t len
= 0, max
= max_io_len(ci
->md
, ci
->sector
, ti
);
499 struct target_io
*tio
;
502 * Allocate a target io object.
504 tio
= alloc_tio(ci
->md
);
507 memset(&tio
->info
, 0, sizeof(tio
->info
));
509 if (ci
->sector_count
<= max
) {
511 * Optimise for the simple case where we can do all of
512 * the remaining io with a single clone.
514 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
,
515 bio
->bi_vcnt
- ci
->idx
, ci
->sector_count
);
516 __map_bio(ti
, clone
, tio
);
517 ci
->sector_count
= 0;
519 } else if (to_sector(bio
->bi_io_vec
[ci
->idx
].bv_len
) <= max
) {
521 * There are some bvecs that don't span targets.
522 * Do as many of these as possible.
525 sector_t remaining
= max
;
528 for (i
= ci
->idx
; remaining
&& (i
< bio
->bi_vcnt
); i
++) {
529 bv_len
= to_sector(bio
->bi_io_vec
[i
].bv_len
);
531 if (bv_len
> remaining
)
538 clone
= clone_bio(bio
, ci
->sector
, ci
->idx
, i
- ci
->idx
, len
);
539 __map_bio(ti
, clone
, tio
);
542 ci
->sector_count
-= len
;
547 * Handle a bvec that must be split between two or more targets.
549 struct bio_vec
*bv
= bio
->bi_io_vec
+ ci
->idx
;
550 sector_t remaining
= to_sector(bv
->bv_len
);
551 unsigned int offset
= 0;
555 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
556 max
= max_io_len(ci
->md
, ci
->sector
, ti
);
558 tio
= alloc_tio(ci
->md
);
561 memset(&tio
->info
, 0, sizeof(tio
->info
));
564 len
= min(remaining
, max
);
566 clone
= split_bvec(bio
, ci
->sector
, ci
->idx
,
567 bv
->bv_offset
+ offset
, len
);
569 __map_bio(ti
, clone
, tio
);
572 ci
->sector_count
-= len
;
573 offset
+= to_bytes(len
);
574 } while (remaining
-= len
);
581 * Split the bio into several clones.
583 static void __split_bio(struct mapped_device
*md
, struct bio
*bio
)
585 struct clone_info ci
;
587 ci
.map
= dm_get_table(md
);
589 bio_io_error(bio
, bio
->bi_size
);
595 ci
.io
= alloc_io(md
);
597 atomic_set(&ci
.io
->io_count
, 1);
600 ci
.sector
= bio
->bi_sector
;
601 ci
.sector_count
= bio_sectors(bio
);
602 ci
.idx
= bio
->bi_idx
;
604 start_io_acct(ci
.io
);
605 while (ci
.sector_count
)
606 __clone_and_map(&ci
);
608 /* drop the extra reference count */
609 dec_pending(ci
.io
, 0);
610 dm_table_put(ci
.map
);
612 /*-----------------------------------------------------------------
614 *---------------------------------------------------------------*/
617 * The request function that just remaps the bio built up by
620 static int dm_request(request_queue_t
*q
, struct bio
*bio
)
623 int rw
= bio_data_dir(bio
);
624 struct mapped_device
*md
= q
->queuedata
;
626 down_read(&md
->io_lock
);
628 disk_stat_inc(dm_disk(md
), ios
[rw
]);
629 disk_stat_add(dm_disk(md
), sectors
[rw
], bio_sectors(bio
));
632 * If we're suspended we have to queue
635 while (test_bit(DMF_BLOCK_IO
, &md
->flags
)) {
636 up_read(&md
->io_lock
);
638 if (bio_rw(bio
) == READA
) {
639 bio_io_error(bio
, bio
->bi_size
);
643 r
= queue_io(md
, bio
);
645 bio_io_error(bio
, bio
->bi_size
);
649 return 0; /* deferred successfully */
652 * We're in a while loop, because someone could suspend
653 * before we get to the following read lock.
655 down_read(&md
->io_lock
);
658 __split_bio(md
, bio
);
659 up_read(&md
->io_lock
);
663 static int dm_flush_all(request_queue_t
*q
, struct gendisk
*disk
,
664 sector_t
*error_sector
)
666 struct mapped_device
*md
= q
->queuedata
;
667 struct dm_table
*map
= dm_get_table(md
);
671 ret
= dm_table_flush_all(map
);
678 static void dm_unplug_all(request_queue_t
*q
)
680 struct mapped_device
*md
= q
->queuedata
;
681 struct dm_table
*map
= dm_get_table(md
);
684 dm_table_unplug_all(map
);
689 static int dm_any_congested(void *congested_data
, int bdi_bits
)
692 struct mapped_device
*md
= (struct mapped_device
*) congested_data
;
693 struct dm_table
*map
= dm_get_table(md
);
695 if (!map
|| test_bit(DMF_BLOCK_IO
, &md
->flags
))
698 r
= dm_table_any_congested(map
, bdi_bits
);
704 /*-----------------------------------------------------------------
705 * An IDR is used to keep track of allocated minor numbers.
706 *---------------------------------------------------------------*/
707 static DECLARE_MUTEX(_minor_lock
);
708 static DEFINE_IDR(_minor_idr
);
710 static void free_minor(unsigned int minor
)
713 idr_remove(&_minor_idr
, minor
);
718 * See if the device with a specific minor # is free.
720 static int specific_minor(struct mapped_device
*md
, unsigned int minor
)
724 if (minor
>= (1 << MINORBITS
))
729 if (idr_find(&_minor_idr
, minor
)) {
734 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
740 r
= idr_get_new_above(&_minor_idr
, md
, minor
, &m
);
746 idr_remove(&_minor_idr
, m
);
756 static int next_free_minor(struct mapped_device
*md
, unsigned int *minor
)
763 r
= idr_pre_get(&_minor_idr
, GFP_KERNEL
);
769 r
= idr_get_new(&_minor_idr
, md
, &m
);
774 if (m
>= (1 << MINORBITS
)) {
775 idr_remove(&_minor_idr
, m
);
787 static struct block_device_operations dm_blk_dops
;
790 * Allocate and initialise a blank device with a given minor.
792 static struct mapped_device
*alloc_dev(unsigned int minor
, int persistent
)
795 struct mapped_device
*md
= kmalloc(sizeof(*md
), GFP_KERNEL
);
798 DMWARN("unable to allocate device, out of memory.");
802 /* get a minor number for the dev */
803 r
= persistent
? specific_minor(md
, minor
) : next_free_minor(md
, &minor
);
807 memset(md
, 0, sizeof(*md
));
808 init_rwsem(&md
->io_lock
);
809 init_MUTEX(&md
->suspend_lock
);
810 rwlock_init(&md
->map_lock
);
811 atomic_set(&md
->holders
, 1);
812 atomic_set(&md
->event_nr
, 0);
814 md
->queue
= blk_alloc_queue(GFP_KERNEL
);
818 md
->queue
->queuedata
= md
;
819 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
820 md
->queue
->backing_dev_info
.congested_data
= md
;
821 blk_queue_make_request(md
->queue
, dm_request
);
822 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
823 md
->queue
->unplug_fn
= dm_unplug_all
;
824 md
->queue
->issue_flush_fn
= dm_flush_all
;
826 md
->io_pool
= mempool_create(MIN_IOS
, mempool_alloc_slab
,
827 mempool_free_slab
, _io_cache
);
831 md
->tio_pool
= mempool_create(MIN_IOS
, mempool_alloc_slab
,
832 mempool_free_slab
, _tio_cache
);
836 md
->disk
= alloc_disk(1);
840 md
->disk
->major
= _major
;
841 md
->disk
->first_minor
= minor
;
842 md
->disk
->fops
= &dm_blk_dops
;
843 md
->disk
->queue
= md
->queue
;
844 md
->disk
->private_data
= md
;
845 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
848 atomic_set(&md
->pending
, 0);
849 init_waitqueue_head(&md
->wait
);
850 init_waitqueue_head(&md
->eventq
);
855 mempool_destroy(md
->tio_pool
);
857 mempool_destroy(md
->io_pool
);
859 blk_cleanup_queue(md
->queue
);
866 static void free_dev(struct mapped_device
*md
)
868 unsigned int minor
= md
->disk
->first_minor
;
870 if (md
->suspended_bdev
) {
871 thaw_bdev(md
->suspended_bdev
, NULL
);
872 bdput(md
->suspended_bdev
);
874 mempool_destroy(md
->tio_pool
);
875 mempool_destroy(md
->io_pool
);
876 del_gendisk(md
->disk
);
879 blk_cleanup_queue(md
->queue
);
884 * Bind a table to the device.
886 static void event_callback(void *context
)
888 struct mapped_device
*md
= (struct mapped_device
*) context
;
890 atomic_inc(&md
->event_nr
);
891 wake_up(&md
->eventq
);
894 static void __set_size(struct mapped_device
*md
, sector_t size
)
896 set_capacity(md
->disk
, size
);
898 mutex_lock(&md
->suspended_bdev
->bd_inode
->i_mutex
);
899 i_size_write(md
->suspended_bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
900 mutex_unlock(&md
->suspended_bdev
->bd_inode
->i_mutex
);
903 static int __bind(struct mapped_device
*md
, struct dm_table
*t
)
905 request_queue_t
*q
= md
->queue
;
908 size
= dm_table_get_size(t
);
909 __set_size(md
, size
);
914 dm_table_event_callback(t
, event_callback
, md
);
916 write_lock(&md
->map_lock
);
918 dm_table_set_restrictions(t
, q
);
919 write_unlock(&md
->map_lock
);
924 static void __unbind(struct mapped_device
*md
)
926 struct dm_table
*map
= md
->map
;
931 dm_table_event_callback(map
, NULL
, NULL
);
932 write_lock(&md
->map_lock
);
934 write_unlock(&md
->map_lock
);
939 * Constructor for a new device.
941 static int create_aux(unsigned int minor
, int persistent
,
942 struct mapped_device
**result
)
944 struct mapped_device
*md
;
946 md
= alloc_dev(minor
, persistent
);
954 int dm_create(struct mapped_device
**result
)
956 return create_aux(0, 0, result
);
959 int dm_create_with_minor(unsigned int minor
, struct mapped_device
**result
)
961 return create_aux(minor
, 1, result
);
964 static struct mapped_device
*dm_find_md(dev_t dev
)
966 struct mapped_device
*md
;
967 unsigned minor
= MINOR(dev
);
969 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
974 md
= idr_find(&_minor_idr
, minor
);
975 if (!md
|| (dm_disk(md
)->first_minor
!= minor
))
983 struct mapped_device
*dm_get_md(dev_t dev
)
985 struct mapped_device
*md
= dm_find_md(dev
);
993 void *dm_get_mdptr(dev_t dev
)
995 struct mapped_device
*md
;
998 md
= dm_find_md(dev
);
1000 mdptr
= md
->interface_ptr
;
1004 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
1006 md
->interface_ptr
= ptr
;
1009 void dm_get(struct mapped_device
*md
)
1011 atomic_inc(&md
->holders
);
1014 void dm_put(struct mapped_device
*md
)
1016 struct dm_table
*map
= dm_get_table(md
);
1018 if (atomic_dec_and_test(&md
->holders
)) {
1019 if (!dm_suspended(md
)) {
1020 dm_table_presuspend_targets(map
);
1021 dm_table_postsuspend_targets(map
);
1031 * Process the deferred bios
1033 static void __flush_deferred_io(struct mapped_device
*md
, struct bio
*c
)
1046 * Swap in a new table (destroying old one).
1048 int dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
1052 down(&md
->suspend_lock
);
1054 /* device must be suspended */
1055 if (!dm_suspended(md
))
1059 r
= __bind(md
, table
);
1062 up(&md
->suspend_lock
);
1067 * Functions to lock and unlock any filesystem running on the
1070 static int lock_fs(struct mapped_device
*md
)
1074 WARN_ON(md
->frozen_sb
);
1076 md
->frozen_sb
= freeze_bdev(md
->suspended_bdev
);
1077 if (IS_ERR(md
->frozen_sb
)) {
1078 r
= PTR_ERR(md
->frozen_sb
);
1079 md
->frozen_sb
= NULL
;
1083 set_bit(DMF_FROZEN
, &md
->flags
);
1085 /* don't bdput right now, we don't want the bdev
1086 * to go away while it is locked.
1091 static void unlock_fs(struct mapped_device
*md
)
1093 if (!test_bit(DMF_FROZEN
, &md
->flags
))
1096 thaw_bdev(md
->suspended_bdev
, md
->frozen_sb
);
1097 md
->frozen_sb
= NULL
;
1098 clear_bit(DMF_FROZEN
, &md
->flags
);
1102 * We need to be able to change a mapping table under a mounted
1103 * filesystem. For example we might want to move some data in
1104 * the background. Before the table can be swapped with
1105 * dm_bind_table, dm_suspend must be called to flush any in
1106 * flight bios and ensure that any further io gets deferred.
1108 int dm_suspend(struct mapped_device
*md
, int do_lockfs
)
1110 struct dm_table
*map
= NULL
;
1111 DECLARE_WAITQUEUE(wait
, current
);
1114 down(&md
->suspend_lock
);
1116 if (dm_suspended(md
))
1119 map
= dm_get_table(md
);
1121 /* This does not get reverted if there's an error later. */
1122 dm_table_presuspend_targets(map
);
1124 md
->suspended_bdev
= bdget_disk(md
->disk
, 0);
1125 if (!md
->suspended_bdev
) {
1126 DMWARN("bdget failed in dm_suspend");
1131 /* Flush I/O to the device. */
1139 * First we set the BLOCK_IO flag so no more ios will be mapped.
1141 down_write(&md
->io_lock
);
1142 set_bit(DMF_BLOCK_IO
, &md
->flags
);
1144 add_wait_queue(&md
->wait
, &wait
);
1145 up_write(&md
->io_lock
);
1149 dm_table_unplug_all(map
);
1152 * Then we wait for the already mapped ios to
1156 set_current_state(TASK_INTERRUPTIBLE
);
1158 if (!atomic_read(&md
->pending
) || signal_pending(current
))
1163 set_current_state(TASK_RUNNING
);
1165 down_write(&md
->io_lock
);
1166 remove_wait_queue(&md
->wait
, &wait
);
1168 /* were we interrupted ? */
1170 if (atomic_read(&md
->pending
)) {
1171 up_write(&md
->io_lock
);
1173 clear_bit(DMF_BLOCK_IO
, &md
->flags
);
1176 up_write(&md
->io_lock
);
1178 dm_table_postsuspend_targets(map
);
1180 set_bit(DMF_SUSPENDED
, &md
->flags
);
1185 if (r
&& md
->suspended_bdev
) {
1186 bdput(md
->suspended_bdev
);
1187 md
->suspended_bdev
= NULL
;
1191 up(&md
->suspend_lock
);
1195 int dm_resume(struct mapped_device
*md
)
1199 struct dm_table
*map
= NULL
;
1201 down(&md
->suspend_lock
);
1202 if (!dm_suspended(md
))
1205 map
= dm_get_table(md
);
1206 if (!map
|| !dm_table_get_size(map
))
1209 dm_table_resume_targets(map
);
1211 down_write(&md
->io_lock
);
1212 clear_bit(DMF_BLOCK_IO
, &md
->flags
);
1214 def
= bio_list_get(&md
->deferred
);
1215 __flush_deferred_io(md
, def
);
1216 up_write(&md
->io_lock
);
1220 bdput(md
->suspended_bdev
);
1221 md
->suspended_bdev
= NULL
;
1223 clear_bit(DMF_SUSPENDED
, &md
->flags
);
1225 dm_table_unplug_all(map
);
1231 up(&md
->suspend_lock
);
1236 /*-----------------------------------------------------------------
1237 * Event notification.
1238 *---------------------------------------------------------------*/
1239 uint32_t dm_get_event_nr(struct mapped_device
*md
)
1241 return atomic_read(&md
->event_nr
);
1244 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
1246 return wait_event_interruptible(md
->eventq
,
1247 (event_nr
!= atomic_read(&md
->event_nr
)));
1251 * The gendisk is only valid as long as you have a reference
1254 struct gendisk
*dm_disk(struct mapped_device
*md
)
1259 int dm_suspended(struct mapped_device
*md
)
1261 return test_bit(DMF_SUSPENDED
, &md
->flags
);
1264 static struct block_device_operations dm_blk_dops
= {
1265 .open
= dm_blk_open
,
1266 .release
= dm_blk_close
,
1267 .owner
= THIS_MODULE
1270 EXPORT_SYMBOL(dm_get_mapinfo
);
1275 module_init(dm_init
);
1276 module_exit(dm_exit
);
1278 module_param(major
, uint
, 0);
1279 MODULE_PARM_DESC(major
, "The major number of the device mapper");
1280 MODULE_DESCRIPTION(DM_NAME
" driver");
1281 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
1282 MODULE_LICENSE("GPL");