2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
11 #include <linux/init.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/moduleparam.h>
15 #include <linux/blkpg.h>
16 #include <linux/bio.h>
17 #include <linux/mempool.h>
18 #include <linux/slab.h>
19 #include <linux/idr.h>
20 #include <linux/hdreg.h>
21 #include <linux/delay.h>
23 #include <trace/events/block.h>
25 #define DM_MSG_PREFIX "core"
29 * ratelimit state to be used in DMXXX_LIMIT().
31 DEFINE_RATELIMIT_STATE(dm_ratelimit_state
,
32 DEFAULT_RATELIMIT_INTERVAL
,
33 DEFAULT_RATELIMIT_BURST
);
34 EXPORT_SYMBOL(dm_ratelimit_state
);
38 * Cookies are numeric values sent with CHANGE and REMOVE
39 * uevents while resuming, removing or renaming the device.
41 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
42 #define DM_COOKIE_LENGTH 24
44 static const char *_name
= DM_NAME
;
46 static unsigned int major
= 0;
47 static unsigned int _major
= 0;
49 static DEFINE_IDR(_minor_idr
);
51 static DEFINE_SPINLOCK(_minor_lock
);
54 * One of these is allocated per bio.
57 struct mapped_device
*md
;
61 unsigned long start_time
;
62 spinlock_t endio_lock
;
66 * For request-based dm.
67 * One of these is allocated per request.
69 struct dm_rq_target_io
{
70 struct mapped_device
*md
;
72 struct request
*orig
, clone
;
78 * For request-based dm - the bio clones we allocate are embedded in these
81 * We allocate these with bio_alloc_bioset, using the front_pad parameter when
82 * the bioset is created - this means the bio has to come at the end of the
85 struct dm_rq_clone_bio_info
{
87 struct dm_rq_target_io
*tio
;
91 union map_info
*dm_get_mapinfo(struct bio
*bio
)
93 if (bio
&& bio
->bi_private
)
94 return &((struct dm_target_io
*)bio
->bi_private
)->info
;
98 union map_info
*dm_get_rq_mapinfo(struct request
*rq
)
100 if (rq
&& rq
->end_io_data
)
101 return &((struct dm_rq_target_io
*)rq
->end_io_data
)->info
;
104 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo
);
106 #define MINOR_ALLOCED ((void *)-1)
109 * Bits for the md->flags field.
111 #define DMF_BLOCK_IO_FOR_SUSPEND 0
112 #define DMF_SUSPENDED 1
114 #define DMF_FREEING 3
115 #define DMF_DELETING 4
116 #define DMF_NOFLUSH_SUSPENDING 5
117 #define DMF_MERGE_IS_OPTIONAL 6
120 * A dummy definition to make RCU happy.
121 * struct dm_table should never be dereferenced in this file.
128 * Work processed by per-device workqueue.
130 struct mapped_device
{
131 struct srcu_struct io_barrier
;
132 struct mutex suspend_lock
;
137 * The current mapping.
138 * Use dm_get_live_table{_fast} or take suspend_lock for
141 struct dm_table
*map
;
145 struct request_queue
*queue
;
147 /* Protect queue and type against concurrent access. */
148 struct mutex type_lock
;
150 struct target_type
*immutable_target_type
;
152 struct gendisk
*disk
;
158 * A list of ios that arrived while we were suspended.
161 wait_queue_head_t wait
;
162 struct work_struct work
;
163 struct bio_list deferred
;
164 spinlock_t deferred_lock
;
167 * Processing queue (flush)
169 struct workqueue_struct
*wq
;
172 * io objects are allocated from here.
182 wait_queue_head_t eventq
;
184 struct list_head uevent_list
;
185 spinlock_t uevent_lock
; /* Protect access to uevent_list */
188 * freeze/thaw support require holding onto a super block
190 struct super_block
*frozen_sb
;
191 struct block_device
*bdev
;
193 /* forced geometry settings */
194 struct hd_geometry geometry
;
199 /* zero-length flush that will be cloned and submitted to targets */
200 struct bio flush_bio
;
204 * For mempools pre-allocation at the table loading time.
206 struct dm_md_mempools
{
212 static struct kmem_cache
*_io_cache
;
213 static struct kmem_cache
*_rq_tio_cache
;
215 static int __init
local_init(void)
219 /* allocate a slab for the dm_ios */
220 _io_cache
= KMEM_CACHE(dm_io
, 0);
224 _rq_tio_cache
= KMEM_CACHE(dm_rq_target_io
, 0);
226 goto out_free_io_cache
;
228 r
= dm_uevent_init();
230 goto out_free_rq_tio_cache
;
233 r
= register_blkdev(_major
, _name
);
235 goto out_uevent_exit
;
244 out_free_rq_tio_cache
:
245 kmem_cache_destroy(_rq_tio_cache
);
247 kmem_cache_destroy(_io_cache
);
252 static void local_exit(void)
254 kmem_cache_destroy(_rq_tio_cache
);
255 kmem_cache_destroy(_io_cache
);
256 unregister_blkdev(_major
, _name
);
261 DMINFO("cleaned up");
264 static int (*_inits
[])(void) __initdata
= {
274 static void (*_exits
[])(void) = {
284 static int __init
dm_init(void)
286 const int count
= ARRAY_SIZE(_inits
);
290 for (i
= 0; i
< count
; i
++) {
305 static void __exit
dm_exit(void)
307 int i
= ARRAY_SIZE(_exits
);
313 * Should be empty by this point.
315 idr_destroy(&_minor_idr
);
319 * Block device functions
321 int dm_deleting_md(struct mapped_device
*md
)
323 return test_bit(DMF_DELETING
, &md
->flags
);
326 static int dm_blk_open(struct block_device
*bdev
, fmode_t mode
)
328 struct mapped_device
*md
;
330 spin_lock(&_minor_lock
);
332 md
= bdev
->bd_disk
->private_data
;
336 if (test_bit(DMF_FREEING
, &md
->flags
) ||
337 dm_deleting_md(md
)) {
343 atomic_inc(&md
->open_count
);
346 spin_unlock(&_minor_lock
);
348 return md
? 0 : -ENXIO
;
351 static void dm_blk_close(struct gendisk
*disk
, fmode_t mode
)
353 struct mapped_device
*md
= disk
->private_data
;
355 spin_lock(&_minor_lock
);
357 atomic_dec(&md
->open_count
);
360 spin_unlock(&_minor_lock
);
363 int dm_open_count(struct mapped_device
*md
)
365 return atomic_read(&md
->open_count
);
369 * Guarantees nothing is using the device before it's deleted.
371 int dm_lock_for_deletion(struct mapped_device
*md
)
375 spin_lock(&_minor_lock
);
377 if (dm_open_count(md
))
380 set_bit(DMF_DELETING
, &md
->flags
);
382 spin_unlock(&_minor_lock
);
387 static int dm_blk_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
389 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
391 return dm_get_geometry(md
, geo
);
394 static int dm_blk_ioctl(struct block_device
*bdev
, fmode_t mode
,
395 unsigned int cmd
, unsigned long arg
)
397 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
399 struct dm_table
*map
;
400 struct dm_target
*tgt
;
404 map
= dm_get_live_table(md
, &srcu_idx
);
406 if (!map
|| !dm_table_get_size(map
))
409 /* We only support devices that have a single target */
410 if (dm_table_get_num_targets(map
) != 1)
413 tgt
= dm_table_get_target(map
, 0);
415 if (dm_suspended_md(md
)) {
420 if (tgt
->type
->ioctl
)
421 r
= tgt
->type
->ioctl(tgt
, cmd
, arg
);
424 dm_put_live_table(md
, srcu_idx
);
426 if (r
== -ENOTCONN
) {
434 static struct dm_io
*alloc_io(struct mapped_device
*md
)
436 return mempool_alloc(md
->io_pool
, GFP_NOIO
);
439 static void free_io(struct mapped_device
*md
, struct dm_io
*io
)
441 mempool_free(io
, md
->io_pool
);
444 static void free_tio(struct mapped_device
*md
, struct dm_target_io
*tio
)
446 bio_put(&tio
->clone
);
449 static struct dm_rq_target_io
*alloc_rq_tio(struct mapped_device
*md
,
452 return mempool_alloc(md
->io_pool
, gfp_mask
);
455 static void free_rq_tio(struct dm_rq_target_io
*tio
)
457 mempool_free(tio
, tio
->md
->io_pool
);
460 static int md_in_flight(struct mapped_device
*md
)
462 return atomic_read(&md
->pending
[READ
]) +
463 atomic_read(&md
->pending
[WRITE
]);
466 static void start_io_acct(struct dm_io
*io
)
468 struct mapped_device
*md
= io
->md
;
470 int rw
= bio_data_dir(io
->bio
);
472 io
->start_time
= jiffies
;
474 cpu
= part_stat_lock();
475 part_round_stats(cpu
, &dm_disk(md
)->part0
);
477 atomic_set(&dm_disk(md
)->part0
.in_flight
[rw
],
478 atomic_inc_return(&md
->pending
[rw
]));
481 static void end_io_acct(struct dm_io
*io
)
483 struct mapped_device
*md
= io
->md
;
484 struct bio
*bio
= io
->bio
;
485 unsigned long duration
= jiffies
- io
->start_time
;
487 int rw
= bio_data_dir(bio
);
489 cpu
= part_stat_lock();
490 part_round_stats(cpu
, &dm_disk(md
)->part0
);
491 part_stat_add(cpu
, &dm_disk(md
)->part0
, ticks
[rw
], duration
);
495 * After this is decremented the bio must not be touched if it is
498 pending
= atomic_dec_return(&md
->pending
[rw
]);
499 atomic_set(&dm_disk(md
)->part0
.in_flight
[rw
], pending
);
500 pending
+= atomic_read(&md
->pending
[rw
^0x1]);
502 /* nudge anyone waiting on suspend queue */
508 * Add the bio to the list of deferred io.
510 static void queue_io(struct mapped_device
*md
, struct bio
*bio
)
514 spin_lock_irqsave(&md
->deferred_lock
, flags
);
515 bio_list_add(&md
->deferred
, bio
);
516 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
517 queue_work(md
->wq
, &md
->work
);
521 * Everyone (including functions in this file), should use this
522 * function to access the md->map field, and make sure they call
523 * dm_put_live_table() when finished.
525 struct dm_table
*dm_get_live_table(struct mapped_device
*md
, int *srcu_idx
) __acquires(md
->io_barrier
)
527 *srcu_idx
= srcu_read_lock(&md
->io_barrier
);
529 return srcu_dereference(md
->map
, &md
->io_barrier
);
532 void dm_put_live_table(struct mapped_device
*md
, int srcu_idx
) __releases(md
->io_barrier
)
534 srcu_read_unlock(&md
->io_barrier
, srcu_idx
);
537 void dm_sync_table(struct mapped_device
*md
)
539 synchronize_srcu(&md
->io_barrier
);
540 synchronize_rcu_expedited();
544 * A fast alternative to dm_get_live_table/dm_put_live_table.
545 * The caller must not block between these two functions.
547 static struct dm_table
*dm_get_live_table_fast(struct mapped_device
*md
) __acquires(RCU
)
550 return rcu_dereference(md
->map
);
553 static void dm_put_live_table_fast(struct mapped_device
*md
) __releases(RCU
)
559 * Get the geometry associated with a dm device
561 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
569 * Set the geometry of a device.
571 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
573 sector_t sz
= (sector_t
)geo
->cylinders
* geo
->heads
* geo
->sectors
;
575 if (geo
->start
> sz
) {
576 DMWARN("Start sector is beyond the geometry limits.");
585 /*-----------------------------------------------------------------
587 * A more elegant soln is in the works that uses the queue
588 * merge fn, unfortunately there are a couple of changes to
589 * the block layer that I want to make for this. So in the
590 * interests of getting something for people to use I give
591 * you this clearly demarcated crap.
592 *---------------------------------------------------------------*/
594 static int __noflush_suspending(struct mapped_device
*md
)
596 return test_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
600 * Decrements the number of outstanding ios that a bio has been
601 * cloned into, completing the original io if necc.
603 static void dec_pending(struct dm_io
*io
, int error
)
608 struct mapped_device
*md
= io
->md
;
610 /* Push-back supersedes any I/O errors */
611 if (unlikely(error
)) {
612 spin_lock_irqsave(&io
->endio_lock
, flags
);
613 if (!(io
->error
> 0 && __noflush_suspending(md
)))
615 spin_unlock_irqrestore(&io
->endio_lock
, flags
);
618 if (atomic_dec_and_test(&io
->io_count
)) {
619 if (io
->error
== DM_ENDIO_REQUEUE
) {
621 * Target requested pushing back the I/O.
623 spin_lock_irqsave(&md
->deferred_lock
, flags
);
624 if (__noflush_suspending(md
))
625 bio_list_add_head(&md
->deferred
, io
->bio
);
627 /* noflush suspend was interrupted. */
629 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
632 io_error
= io
->error
;
637 if (io_error
== DM_ENDIO_REQUEUE
)
640 if ((bio
->bi_rw
& REQ_FLUSH
) && bio
->bi_size
) {
642 * Preflush done for flush with data, reissue
645 bio
->bi_rw
&= ~REQ_FLUSH
;
648 /* done with normal IO or empty flush */
649 trace_block_bio_complete(md
->queue
, bio
, io_error
);
650 bio_endio(bio
, io_error
);
655 static void clone_endio(struct bio
*bio
, int error
)
658 struct dm_target_io
*tio
= bio
->bi_private
;
659 struct dm_io
*io
= tio
->io
;
660 struct mapped_device
*md
= tio
->io
->md
;
661 dm_endio_fn endio
= tio
->ti
->type
->end_io
;
663 if (!bio_flagged(bio
, BIO_UPTODATE
) && !error
)
667 r
= endio(tio
->ti
, bio
, error
);
668 if (r
< 0 || r
== DM_ENDIO_REQUEUE
)
670 * error and requeue request are handled
674 else if (r
== DM_ENDIO_INCOMPLETE
)
675 /* The target will handle the io */
678 DMWARN("unimplemented target endio return value: %d", r
);
684 dec_pending(io
, error
);
688 * Partial completion handling for request-based dm
690 static void end_clone_bio(struct bio
*clone
, int error
)
692 struct dm_rq_clone_bio_info
*info
= clone
->bi_private
;
693 struct dm_rq_target_io
*tio
= info
->tio
;
694 struct bio
*bio
= info
->orig
;
695 unsigned int nr_bytes
= info
->orig
->bi_size
;
701 * An error has already been detected on the request.
702 * Once error occurred, just let clone->end_io() handle
708 * Don't notice the error to the upper layer yet.
709 * The error handling decision is made by the target driver,
710 * when the request is completed.
717 * I/O for the bio successfully completed.
718 * Notice the data completion to the upper layer.
722 * bios are processed from the head of the list.
723 * So the completing bio should always be rq->bio.
724 * If it's not, something wrong is happening.
726 if (tio
->orig
->bio
!= bio
)
727 DMERR("bio completion is going in the middle of the request");
730 * Update the original request.
731 * Do not use blk_end_request() here, because it may complete
732 * the original request before the clone, and break the ordering.
734 blk_update_request(tio
->orig
, 0, nr_bytes
);
738 * Don't touch any member of the md after calling this function because
739 * the md may be freed in dm_put() at the end of this function.
740 * Or do dm_get() before calling this function and dm_put() later.
742 static void rq_completed(struct mapped_device
*md
, int rw
, int run_queue
)
744 atomic_dec(&md
->pending
[rw
]);
746 /* nudge anyone waiting on suspend queue */
747 if (!md_in_flight(md
))
751 * Run this off this callpath, as drivers could invoke end_io while
752 * inside their request_fn (and holding the queue lock). Calling
753 * back into ->request_fn() could deadlock attempting to grab the
757 blk_run_queue_async(md
->queue
);
760 * dm_put() must be at the end of this function. See the comment above
765 static void free_rq_clone(struct request
*clone
)
767 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
769 blk_rq_unprep_clone(clone
);
774 * Complete the clone and the original request.
775 * Must be called without queue lock.
777 static void dm_end_request(struct request
*clone
, int error
)
779 int rw
= rq_data_dir(clone
);
780 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
781 struct mapped_device
*md
= tio
->md
;
782 struct request
*rq
= tio
->orig
;
784 if (rq
->cmd_type
== REQ_TYPE_BLOCK_PC
) {
785 rq
->errors
= clone
->errors
;
786 rq
->resid_len
= clone
->resid_len
;
790 * We are using the sense buffer of the original
792 * So setting the length of the sense data is enough.
794 rq
->sense_len
= clone
->sense_len
;
797 free_rq_clone(clone
);
798 blk_end_request_all(rq
, error
);
799 rq_completed(md
, rw
, true);
802 static void dm_unprep_request(struct request
*rq
)
804 struct request
*clone
= rq
->special
;
807 rq
->cmd_flags
&= ~REQ_DONTPREP
;
809 free_rq_clone(clone
);
813 * Requeue the original request of a clone.
815 void dm_requeue_unmapped_request(struct request
*clone
)
817 int rw
= rq_data_dir(clone
);
818 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
819 struct mapped_device
*md
= tio
->md
;
820 struct request
*rq
= tio
->orig
;
821 struct request_queue
*q
= rq
->q
;
824 dm_unprep_request(rq
);
826 spin_lock_irqsave(q
->queue_lock
, flags
);
827 blk_requeue_request(q
, rq
);
828 spin_unlock_irqrestore(q
->queue_lock
, flags
);
830 rq_completed(md
, rw
, 0);
832 EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request
);
834 static void __stop_queue(struct request_queue
*q
)
839 static void stop_queue(struct request_queue
*q
)
843 spin_lock_irqsave(q
->queue_lock
, flags
);
845 spin_unlock_irqrestore(q
->queue_lock
, flags
);
848 static void __start_queue(struct request_queue
*q
)
850 if (blk_queue_stopped(q
))
854 static void start_queue(struct request_queue
*q
)
858 spin_lock_irqsave(q
->queue_lock
, flags
);
860 spin_unlock_irqrestore(q
->queue_lock
, flags
);
863 static void dm_done(struct request
*clone
, int error
, bool mapped
)
866 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
867 dm_request_endio_fn rq_end_io
= NULL
;
870 rq_end_io
= tio
->ti
->type
->rq_end_io
;
872 if (mapped
&& rq_end_io
)
873 r
= rq_end_io(tio
->ti
, clone
, error
, &tio
->info
);
877 /* The target wants to complete the I/O */
878 dm_end_request(clone
, r
);
879 else if (r
== DM_ENDIO_INCOMPLETE
)
880 /* The target will handle the I/O */
882 else if (r
== DM_ENDIO_REQUEUE
)
883 /* The target wants to requeue the I/O */
884 dm_requeue_unmapped_request(clone
);
886 DMWARN("unimplemented target endio return value: %d", r
);
892 * Request completion handler for request-based dm
894 static void dm_softirq_done(struct request
*rq
)
897 struct request
*clone
= rq
->completion_data
;
898 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
900 if (rq
->cmd_flags
& REQ_FAILED
)
903 dm_done(clone
, tio
->error
, mapped
);
907 * Complete the clone and the original request with the error status
908 * through softirq context.
910 static void dm_complete_request(struct request
*clone
, int error
)
912 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
913 struct request
*rq
= tio
->orig
;
916 rq
->completion_data
= clone
;
917 blk_complete_request(rq
);
921 * Complete the not-mapped clone and the original request with the error status
922 * through softirq context.
923 * Target's rq_end_io() function isn't called.
924 * This may be used when the target's map_rq() function fails.
926 void dm_kill_unmapped_request(struct request
*clone
, int error
)
928 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
929 struct request
*rq
= tio
->orig
;
931 rq
->cmd_flags
|= REQ_FAILED
;
932 dm_complete_request(clone
, error
);
934 EXPORT_SYMBOL_GPL(dm_kill_unmapped_request
);
937 * Called with the queue lock held
939 static void end_clone_request(struct request
*clone
, int error
)
942 * For just cleaning up the information of the queue in which
943 * the clone was dispatched.
944 * The clone is *NOT* freed actually here because it is alloced from
945 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
947 __blk_put_request(clone
->q
, clone
);
950 * Actual request completion is done in a softirq context which doesn't
951 * hold the queue lock. Otherwise, deadlock could occur because:
952 * - another request may be submitted by the upper level driver
953 * of the stacking during the completion
954 * - the submission which requires queue lock may be done
957 dm_complete_request(clone
, error
);
961 * Return maximum size of I/O possible at the supplied sector up to the current
964 static sector_t
max_io_len_target_boundary(sector_t sector
, struct dm_target
*ti
)
966 sector_t target_offset
= dm_target_offset(ti
, sector
);
968 return ti
->len
- target_offset
;
971 static sector_t
max_io_len(sector_t sector
, struct dm_target
*ti
)
973 sector_t len
= max_io_len_target_boundary(sector
, ti
);
974 sector_t offset
, max_len
;
977 * Does the target need to split even further?
979 if (ti
->max_io_len
) {
980 offset
= dm_target_offset(ti
, sector
);
981 if (unlikely(ti
->max_io_len
& (ti
->max_io_len
- 1)))
982 max_len
= sector_div(offset
, ti
->max_io_len
);
984 max_len
= offset
& (ti
->max_io_len
- 1);
985 max_len
= ti
->max_io_len
- max_len
;
994 int dm_set_target_max_io_len(struct dm_target
*ti
, sector_t len
)
996 if (len
> UINT_MAX
) {
997 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
998 (unsigned long long)len
, UINT_MAX
);
999 ti
->error
= "Maximum size of target IO is too large";
1003 ti
->max_io_len
= (uint32_t) len
;
1007 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len
);
1009 static void __map_bio(struct dm_target_io
*tio
)
1013 struct mapped_device
*md
;
1014 struct bio
*clone
= &tio
->clone
;
1015 struct dm_target
*ti
= tio
->ti
;
1017 clone
->bi_end_io
= clone_endio
;
1018 clone
->bi_private
= tio
;
1021 * Map the clone. If r == 0 we don't need to do
1022 * anything, the target has assumed ownership of
1025 atomic_inc(&tio
->io
->io_count
);
1026 sector
= clone
->bi_sector
;
1027 r
= ti
->type
->map(ti
, clone
);
1028 if (r
== DM_MAPIO_REMAPPED
) {
1029 /* the bio has been remapped so dispatch it */
1031 trace_block_bio_remap(bdev_get_queue(clone
->bi_bdev
), clone
,
1032 tio
->io
->bio
->bi_bdev
->bd_dev
, sector
);
1034 generic_make_request(clone
);
1035 } else if (r
< 0 || r
== DM_MAPIO_REQUEUE
) {
1036 /* error the io and bail out, or requeue it if needed */
1038 dec_pending(tio
->io
, r
);
1041 DMWARN("unimplemented target map return value: %d", r
);
1047 struct mapped_device
*md
;
1048 struct dm_table
*map
;
1052 sector_t sector_count
;
1056 static void bio_setup_sector(struct bio
*bio
, sector_t sector
, sector_t len
)
1058 bio
->bi_sector
= sector
;
1059 bio
->bi_size
= to_bytes(len
);
1062 static void bio_setup_bv(struct bio
*bio
, unsigned short idx
, unsigned short bv_count
)
1065 bio
->bi_vcnt
= idx
+ bv_count
;
1066 bio
->bi_flags
&= ~(1 << BIO_SEG_VALID
);
1069 static void clone_bio_integrity(struct bio
*bio
, struct bio
*clone
,
1070 unsigned short idx
, unsigned len
, unsigned offset
,
1073 if (!bio_integrity(bio
))
1076 bio_integrity_clone(clone
, bio
, GFP_NOIO
);
1079 bio_integrity_trim(clone
, bio_sector_offset(bio
, idx
, offset
), len
);
1083 * Creates a little bio that just does part of a bvec.
1085 static void clone_split_bio(struct dm_target_io
*tio
, struct bio
*bio
,
1086 sector_t sector
, unsigned short idx
,
1087 unsigned offset
, unsigned len
)
1089 struct bio
*clone
= &tio
->clone
;
1090 struct bio_vec
*bv
= bio
->bi_io_vec
+ idx
;
1092 *clone
->bi_io_vec
= *bv
;
1094 bio_setup_sector(clone
, sector
, len
);
1096 clone
->bi_bdev
= bio
->bi_bdev
;
1097 clone
->bi_rw
= bio
->bi_rw
;
1099 clone
->bi_io_vec
->bv_offset
= offset
;
1100 clone
->bi_io_vec
->bv_len
= clone
->bi_size
;
1101 clone
->bi_flags
|= 1 << BIO_CLONED
;
1103 clone_bio_integrity(bio
, clone
, idx
, len
, offset
, 1);
1107 * Creates a bio that consists of range of complete bvecs.
1109 static void clone_bio(struct dm_target_io
*tio
, struct bio
*bio
,
1110 sector_t sector
, unsigned short idx
,
1111 unsigned short bv_count
, unsigned len
)
1113 struct bio
*clone
= &tio
->clone
;
1116 __bio_clone(clone
, bio
);
1117 bio_setup_sector(clone
, sector
, len
);
1118 bio_setup_bv(clone
, idx
, bv_count
);
1120 if (idx
!= bio
->bi_idx
|| clone
->bi_size
< bio
->bi_size
)
1122 clone_bio_integrity(bio
, clone
, idx
, len
, 0, trim
);
1125 static struct dm_target_io
*alloc_tio(struct clone_info
*ci
,
1126 struct dm_target
*ti
, int nr_iovecs
,
1127 unsigned target_bio_nr
)
1129 struct dm_target_io
*tio
;
1132 clone
= bio_alloc_bioset(GFP_NOIO
, nr_iovecs
, ci
->md
->bs
);
1133 tio
= container_of(clone
, struct dm_target_io
, clone
);
1137 memset(&tio
->info
, 0, sizeof(tio
->info
));
1138 tio
->target_bio_nr
= target_bio_nr
;
1143 static void __clone_and_map_simple_bio(struct clone_info
*ci
,
1144 struct dm_target
*ti
,
1145 unsigned target_bio_nr
, sector_t len
)
1147 struct dm_target_io
*tio
= alloc_tio(ci
, ti
, ci
->bio
->bi_max_vecs
, target_bio_nr
);
1148 struct bio
*clone
= &tio
->clone
;
1151 * Discard requests require the bio's inline iovecs be initialized.
1152 * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
1153 * and discard, so no need for concern about wasted bvec allocations.
1155 __bio_clone(clone
, ci
->bio
);
1157 bio_setup_sector(clone
, ci
->sector
, len
);
1162 static void __send_duplicate_bios(struct clone_info
*ci
, struct dm_target
*ti
,
1163 unsigned num_bios
, sector_t len
)
1165 unsigned target_bio_nr
;
1167 for (target_bio_nr
= 0; target_bio_nr
< num_bios
; target_bio_nr
++)
1168 __clone_and_map_simple_bio(ci
, ti
, target_bio_nr
, len
);
1171 static int __send_empty_flush(struct clone_info
*ci
)
1173 unsigned target_nr
= 0;
1174 struct dm_target
*ti
;
1176 BUG_ON(bio_has_data(ci
->bio
));
1177 while ((ti
= dm_table_get_target(ci
->map
, target_nr
++)))
1178 __send_duplicate_bios(ci
, ti
, ti
->num_flush_bios
, 0);
1183 static void __clone_and_map_data_bio(struct clone_info
*ci
, struct dm_target
*ti
,
1184 sector_t sector
, int nr_iovecs
,
1185 unsigned short idx
, unsigned short bv_count
,
1186 unsigned offset
, unsigned len
,
1187 unsigned split_bvec
)
1189 struct bio
*bio
= ci
->bio
;
1190 struct dm_target_io
*tio
;
1191 unsigned target_bio_nr
;
1192 unsigned num_target_bios
= 1;
1195 * Does the target want to receive duplicate copies of the bio?
1197 if (bio_data_dir(bio
) == WRITE
&& ti
->num_write_bios
)
1198 num_target_bios
= ti
->num_write_bios(ti
, bio
);
1200 for (target_bio_nr
= 0; target_bio_nr
< num_target_bios
; target_bio_nr
++) {
1201 tio
= alloc_tio(ci
, ti
, nr_iovecs
, target_bio_nr
);
1203 clone_split_bio(tio
, bio
, sector
, idx
, offset
, len
);
1205 clone_bio(tio
, bio
, sector
, idx
, bv_count
, len
);
1210 typedef unsigned (*get_num_bios_fn
)(struct dm_target
*ti
);
1212 static unsigned get_num_discard_bios(struct dm_target
*ti
)
1214 return ti
->num_discard_bios
;
1217 static unsigned get_num_write_same_bios(struct dm_target
*ti
)
1219 return ti
->num_write_same_bios
;
1222 typedef bool (*is_split_required_fn
)(struct dm_target
*ti
);
1224 static bool is_split_required_for_discard(struct dm_target
*ti
)
1226 return ti
->split_discard_bios
;
1229 static int __send_changing_extent_only(struct clone_info
*ci
,
1230 get_num_bios_fn get_num_bios
,
1231 is_split_required_fn is_split_required
)
1233 struct dm_target
*ti
;
1238 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1239 if (!dm_target_is_valid(ti
))
1243 * Even though the device advertised support for this type of
1244 * request, that does not mean every target supports it, and
1245 * reconfiguration might also have changed that since the
1246 * check was performed.
1248 num_bios
= get_num_bios
? get_num_bios(ti
) : 0;
1252 if (is_split_required
&& !is_split_required(ti
))
1253 len
= min(ci
->sector_count
, max_io_len_target_boundary(ci
->sector
, ti
));
1255 len
= min(ci
->sector_count
, max_io_len(ci
->sector
, ti
));
1257 __send_duplicate_bios(ci
, ti
, num_bios
, len
);
1260 } while (ci
->sector_count
-= len
);
1265 static int __send_discard(struct clone_info
*ci
)
1267 return __send_changing_extent_only(ci
, get_num_discard_bios
,
1268 is_split_required_for_discard
);
1271 static int __send_write_same(struct clone_info
*ci
)
1273 return __send_changing_extent_only(ci
, get_num_write_same_bios
, NULL
);
1277 * Find maximum number of sectors / bvecs we can process with a single bio.
1279 static sector_t
__len_within_target(struct clone_info
*ci
, sector_t max
, int *idx
)
1281 struct bio
*bio
= ci
->bio
;
1282 sector_t bv_len
, total_len
= 0;
1284 for (*idx
= ci
->idx
; max
&& (*idx
< bio
->bi_vcnt
); (*idx
)++) {
1285 bv_len
= to_sector(bio
->bi_io_vec
[*idx
].bv_len
);
1291 total_len
+= bv_len
;
1297 static int __split_bvec_across_targets(struct clone_info
*ci
,
1298 struct dm_target
*ti
, sector_t max
)
1300 struct bio
*bio
= ci
->bio
;
1301 struct bio_vec
*bv
= bio
->bi_io_vec
+ ci
->idx
;
1302 sector_t remaining
= to_sector(bv
->bv_len
);
1303 unsigned offset
= 0;
1308 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1309 if (!dm_target_is_valid(ti
))
1312 max
= max_io_len(ci
->sector
, ti
);
1315 len
= min(remaining
, max
);
1317 __clone_and_map_data_bio(ci
, ti
, ci
->sector
, 1, ci
->idx
, 0,
1318 bv
->bv_offset
+ offset
, len
, 1);
1321 ci
->sector_count
-= len
;
1322 offset
+= to_bytes(len
);
1323 } while (remaining
-= len
);
1331 * Select the correct strategy for processing a non-flush bio.
1333 static int __split_and_process_non_flush(struct clone_info
*ci
)
1335 struct bio
*bio
= ci
->bio
;
1336 struct dm_target
*ti
;
1340 if (unlikely(bio
->bi_rw
& REQ_DISCARD
))
1341 return __send_discard(ci
);
1342 else if (unlikely(bio
->bi_rw
& REQ_WRITE_SAME
))
1343 return __send_write_same(ci
);
1345 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1346 if (!dm_target_is_valid(ti
))
1349 max
= max_io_len(ci
->sector
, ti
);
1352 * Optimise for the simple case where we can do all of
1353 * the remaining io with a single clone.
1355 if (ci
->sector_count
<= max
) {
1356 __clone_and_map_data_bio(ci
, ti
, ci
->sector
, bio
->bi_max_vecs
,
1357 ci
->idx
, bio
->bi_vcnt
- ci
->idx
, 0,
1358 ci
->sector_count
, 0);
1359 ci
->sector_count
= 0;
1364 * There are some bvecs that don't span targets.
1365 * Do as many of these as possible.
1367 if (to_sector(bio
->bi_io_vec
[ci
->idx
].bv_len
) <= max
) {
1368 len
= __len_within_target(ci
, max
, &idx
);
1370 __clone_and_map_data_bio(ci
, ti
, ci
->sector
, bio
->bi_max_vecs
,
1371 ci
->idx
, idx
- ci
->idx
, 0, len
, 0);
1374 ci
->sector_count
-= len
;
1381 * Handle a bvec that must be split between two or more targets.
1383 return __split_bvec_across_targets(ci
, ti
, max
);
1387 * Entry point to split a bio into clones and submit them to the targets.
1389 static void __split_and_process_bio(struct mapped_device
*md
,
1390 struct dm_table
*map
, struct bio
*bio
)
1392 struct clone_info ci
;
1395 if (unlikely(!map
)) {
1402 ci
.io
= alloc_io(md
);
1404 atomic_set(&ci
.io
->io_count
, 1);
1407 spin_lock_init(&ci
.io
->endio_lock
);
1408 ci
.sector
= bio
->bi_sector
;
1409 ci
.idx
= bio
->bi_idx
;
1411 start_io_acct(ci
.io
);
1413 if (bio
->bi_rw
& REQ_FLUSH
) {
1414 ci
.bio
= &ci
.md
->flush_bio
;
1415 ci
.sector_count
= 0;
1416 error
= __send_empty_flush(&ci
);
1417 /* dec_pending submits any data associated with flush */
1420 ci
.sector_count
= bio_sectors(bio
);
1421 while (ci
.sector_count
&& !error
)
1422 error
= __split_and_process_non_flush(&ci
);
1425 /* drop the extra reference count */
1426 dec_pending(ci
.io
, error
);
1428 /*-----------------------------------------------------------------
1430 *---------------------------------------------------------------*/
1432 static int dm_merge_bvec(struct request_queue
*q
,
1433 struct bvec_merge_data
*bvm
,
1434 struct bio_vec
*biovec
)
1436 struct mapped_device
*md
= q
->queuedata
;
1437 struct dm_table
*map
= dm_get_live_table_fast(md
);
1438 struct dm_target
*ti
;
1439 sector_t max_sectors
;
1445 ti
= dm_table_find_target(map
, bvm
->bi_sector
);
1446 if (!dm_target_is_valid(ti
))
1450 * Find maximum amount of I/O that won't need splitting
1452 max_sectors
= min(max_io_len(bvm
->bi_sector
, ti
),
1453 (sector_t
) BIO_MAX_SECTORS
);
1454 max_size
= (max_sectors
<< SECTOR_SHIFT
) - bvm
->bi_size
;
1459 * merge_bvec_fn() returns number of bytes
1460 * it can accept at this offset
1461 * max is precomputed maximal io size
1463 if (max_size
&& ti
->type
->merge
)
1464 max_size
= ti
->type
->merge(ti
, bvm
, biovec
, max_size
);
1466 * If the target doesn't support merge method and some of the devices
1467 * provided their merge_bvec method (we know this by looking at
1468 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1469 * entries. So always set max_size to 0, and the code below allows
1472 else if (queue_max_hw_sectors(q
) <= PAGE_SIZE
>> 9)
1477 dm_put_live_table_fast(md
);
1479 * Always allow an entire first page
1481 if (max_size
<= biovec
->bv_len
&& !(bvm
->bi_size
>> SECTOR_SHIFT
))
1482 max_size
= biovec
->bv_len
;
1488 * The request function that just remaps the bio built up by
1491 static void _dm_request(struct request_queue
*q
, struct bio
*bio
)
1493 int rw
= bio_data_dir(bio
);
1494 struct mapped_device
*md
= q
->queuedata
;
1497 struct dm_table
*map
;
1499 map
= dm_get_live_table(md
, &srcu_idx
);
1501 cpu
= part_stat_lock();
1502 part_stat_inc(cpu
, &dm_disk(md
)->part0
, ios
[rw
]);
1503 part_stat_add(cpu
, &dm_disk(md
)->part0
, sectors
[rw
], bio_sectors(bio
));
1506 /* if we're suspended, we have to queue this io for later */
1507 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
))) {
1508 dm_put_live_table(md
, srcu_idx
);
1510 if (bio_rw(bio
) != READA
)
1517 __split_and_process_bio(md
, map
, bio
);
1518 dm_put_live_table(md
, srcu_idx
);
1522 static int dm_request_based(struct mapped_device
*md
)
1524 return blk_queue_stackable(md
->queue
);
1527 static void dm_request(struct request_queue
*q
, struct bio
*bio
)
1529 struct mapped_device
*md
= q
->queuedata
;
1531 if (dm_request_based(md
))
1532 blk_queue_bio(q
, bio
);
1534 _dm_request(q
, bio
);
1537 void dm_dispatch_request(struct request
*rq
)
1541 if (blk_queue_io_stat(rq
->q
))
1542 rq
->cmd_flags
|= REQ_IO_STAT
;
1544 rq
->start_time
= jiffies
;
1545 r
= blk_insert_cloned_request(rq
->q
, rq
);
1547 dm_complete_request(rq
, r
);
1549 EXPORT_SYMBOL_GPL(dm_dispatch_request
);
1551 static int dm_rq_bio_constructor(struct bio
*bio
, struct bio
*bio_orig
,
1554 struct dm_rq_target_io
*tio
= data
;
1555 struct dm_rq_clone_bio_info
*info
=
1556 container_of(bio
, struct dm_rq_clone_bio_info
, clone
);
1558 info
->orig
= bio_orig
;
1560 bio
->bi_end_io
= end_clone_bio
;
1561 bio
->bi_private
= info
;
1566 static int setup_clone(struct request
*clone
, struct request
*rq
,
1567 struct dm_rq_target_io
*tio
)
1571 r
= blk_rq_prep_clone(clone
, rq
, tio
->md
->bs
, GFP_ATOMIC
,
1572 dm_rq_bio_constructor
, tio
);
1576 clone
->cmd
= rq
->cmd
;
1577 clone
->cmd_len
= rq
->cmd_len
;
1578 clone
->sense
= rq
->sense
;
1579 clone
->buffer
= rq
->buffer
;
1580 clone
->end_io
= end_clone_request
;
1581 clone
->end_io_data
= tio
;
1586 static struct request
*clone_rq(struct request
*rq
, struct mapped_device
*md
,
1589 struct request
*clone
;
1590 struct dm_rq_target_io
*tio
;
1592 tio
= alloc_rq_tio(md
, gfp_mask
);
1600 memset(&tio
->info
, 0, sizeof(tio
->info
));
1602 clone
= &tio
->clone
;
1603 if (setup_clone(clone
, rq
, tio
)) {
1613 * Called with the queue lock held.
1615 static int dm_prep_fn(struct request_queue
*q
, struct request
*rq
)
1617 struct mapped_device
*md
= q
->queuedata
;
1618 struct request
*clone
;
1620 if (unlikely(rq
->special
)) {
1621 DMWARN("Already has something in rq->special.");
1622 return BLKPREP_KILL
;
1625 clone
= clone_rq(rq
, md
, GFP_ATOMIC
);
1627 return BLKPREP_DEFER
;
1629 rq
->special
= clone
;
1630 rq
->cmd_flags
|= REQ_DONTPREP
;
1637 * 0 : the request has been processed (not requeued)
1638 * !0 : the request has been requeued
1640 static int map_request(struct dm_target
*ti
, struct request
*clone
,
1641 struct mapped_device
*md
)
1643 int r
, requeued
= 0;
1644 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1647 r
= ti
->type
->map_rq(ti
, clone
, &tio
->info
);
1649 case DM_MAPIO_SUBMITTED
:
1650 /* The target has taken the I/O to submit by itself later */
1652 case DM_MAPIO_REMAPPED
:
1653 /* The target has remapped the I/O so dispatch it */
1654 trace_block_rq_remap(clone
->q
, clone
, disk_devt(dm_disk(md
)),
1655 blk_rq_pos(tio
->orig
));
1656 dm_dispatch_request(clone
);
1658 case DM_MAPIO_REQUEUE
:
1659 /* The target wants to requeue the I/O */
1660 dm_requeue_unmapped_request(clone
);
1665 DMWARN("unimplemented target map return value: %d", r
);
1669 /* The target wants to complete the I/O */
1670 dm_kill_unmapped_request(clone
, r
);
1677 static struct request
*dm_start_request(struct mapped_device
*md
, struct request
*orig
)
1679 struct request
*clone
;
1681 blk_start_request(orig
);
1682 clone
= orig
->special
;
1683 atomic_inc(&md
->pending
[rq_data_dir(clone
)]);
1686 * Hold the md reference here for the in-flight I/O.
1687 * We can't rely on the reference count by device opener,
1688 * because the device may be closed during the request completion
1689 * when all bios are completed.
1690 * See the comment in rq_completed() too.
1698 * q->request_fn for request-based dm.
1699 * Called with the queue lock held.
1701 static void dm_request_fn(struct request_queue
*q
)
1703 struct mapped_device
*md
= q
->queuedata
;
1705 struct dm_table
*map
= dm_get_live_table(md
, &srcu_idx
);
1706 struct dm_target
*ti
;
1707 struct request
*rq
, *clone
;
1711 * For suspend, check blk_queue_stopped() and increment
1712 * ->pending within a single queue_lock not to increment the
1713 * number of in-flight I/Os after the queue is stopped in
1716 while (!blk_queue_stopped(q
)) {
1717 rq
= blk_peek_request(q
);
1721 /* always use block 0 to find the target for flushes for now */
1723 if (!(rq
->cmd_flags
& REQ_FLUSH
))
1724 pos
= blk_rq_pos(rq
);
1726 ti
= dm_table_find_target(map
, pos
);
1727 if (!dm_target_is_valid(ti
)) {
1729 * Must perform setup, that dm_done() requires,
1730 * before calling dm_kill_unmapped_request
1732 DMERR_LIMIT("request attempted access beyond the end of device");
1733 clone
= dm_start_request(md
, rq
);
1734 dm_kill_unmapped_request(clone
, -EIO
);
1738 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
1741 clone
= dm_start_request(md
, rq
);
1743 spin_unlock(q
->queue_lock
);
1744 if (map_request(ti
, clone
, md
))
1747 BUG_ON(!irqs_disabled());
1748 spin_lock(q
->queue_lock
);
1754 BUG_ON(!irqs_disabled());
1755 spin_lock(q
->queue_lock
);
1758 blk_delay_queue(q
, HZ
/ 10);
1760 dm_put_live_table(md
, srcu_idx
);
1763 int dm_underlying_device_busy(struct request_queue
*q
)
1765 return blk_lld_busy(q
);
1767 EXPORT_SYMBOL_GPL(dm_underlying_device_busy
);
1769 static int dm_lld_busy(struct request_queue
*q
)
1772 struct mapped_device
*md
= q
->queuedata
;
1773 struct dm_table
*map
= dm_get_live_table_fast(md
);
1775 if (!map
|| test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
))
1778 r
= dm_table_any_busy_target(map
);
1780 dm_put_live_table_fast(md
);
1785 static int dm_any_congested(void *congested_data
, int bdi_bits
)
1788 struct mapped_device
*md
= congested_data
;
1789 struct dm_table
*map
;
1791 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
1792 map
= dm_get_live_table_fast(md
);
1795 * Request-based dm cares about only own queue for
1796 * the query about congestion status of request_queue
1798 if (dm_request_based(md
))
1799 r
= md
->queue
->backing_dev_info
.state
&
1802 r
= dm_table_any_congested(map
, bdi_bits
);
1804 dm_put_live_table_fast(md
);
1810 /*-----------------------------------------------------------------
1811 * An IDR is used to keep track of allocated minor numbers.
1812 *---------------------------------------------------------------*/
1813 static void free_minor(int minor
)
1815 spin_lock(&_minor_lock
);
1816 idr_remove(&_minor_idr
, minor
);
1817 spin_unlock(&_minor_lock
);
1821 * See if the device with a specific minor # is free.
1823 static int specific_minor(int minor
)
1827 if (minor
>= (1 << MINORBITS
))
1830 idr_preload(GFP_KERNEL
);
1831 spin_lock(&_minor_lock
);
1833 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, minor
, minor
+ 1, GFP_NOWAIT
);
1835 spin_unlock(&_minor_lock
);
1838 return r
== -ENOSPC
? -EBUSY
: r
;
1842 static int next_free_minor(int *minor
)
1846 idr_preload(GFP_KERNEL
);
1847 spin_lock(&_minor_lock
);
1849 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, 0, 1 << MINORBITS
, GFP_NOWAIT
);
1851 spin_unlock(&_minor_lock
);
1859 static const struct block_device_operations dm_blk_dops
;
1861 static void dm_wq_work(struct work_struct
*work
);
1863 static void dm_init_md_queue(struct mapped_device
*md
)
1866 * Request-based dm devices cannot be stacked on top of bio-based dm
1867 * devices. The type of this dm device has not been decided yet.
1868 * The type is decided at the first table loading time.
1869 * To prevent problematic device stacking, clear the queue flag
1870 * for request stacking support until then.
1872 * This queue is new, so no concurrency on the queue_flags.
1874 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE
, md
->queue
);
1876 md
->queue
->queuedata
= md
;
1877 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
1878 md
->queue
->backing_dev_info
.congested_data
= md
;
1879 blk_queue_make_request(md
->queue
, dm_request
);
1880 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
1881 blk_queue_merge_bvec(md
->queue
, dm_merge_bvec
);
1885 * Allocate and initialise a blank device with a given minor.
1887 static struct mapped_device
*alloc_dev(int minor
)
1890 struct mapped_device
*md
= kzalloc(sizeof(*md
), GFP_KERNEL
);
1894 DMWARN("unable to allocate device, out of memory.");
1898 if (!try_module_get(THIS_MODULE
))
1899 goto bad_module_get
;
1901 /* get a minor number for the dev */
1902 if (minor
== DM_ANY_MINOR
)
1903 r
= next_free_minor(&minor
);
1905 r
= specific_minor(minor
);
1909 r
= init_srcu_struct(&md
->io_barrier
);
1911 goto bad_io_barrier
;
1913 md
->type
= DM_TYPE_NONE
;
1914 mutex_init(&md
->suspend_lock
);
1915 mutex_init(&md
->type_lock
);
1916 spin_lock_init(&md
->deferred_lock
);
1917 atomic_set(&md
->holders
, 1);
1918 atomic_set(&md
->open_count
, 0);
1919 atomic_set(&md
->event_nr
, 0);
1920 atomic_set(&md
->uevent_seq
, 0);
1921 INIT_LIST_HEAD(&md
->uevent_list
);
1922 spin_lock_init(&md
->uevent_lock
);
1924 md
->queue
= blk_alloc_queue(GFP_KERNEL
);
1928 dm_init_md_queue(md
);
1930 md
->disk
= alloc_disk(1);
1934 atomic_set(&md
->pending
[0], 0);
1935 atomic_set(&md
->pending
[1], 0);
1936 init_waitqueue_head(&md
->wait
);
1937 INIT_WORK(&md
->work
, dm_wq_work
);
1938 init_waitqueue_head(&md
->eventq
);
1940 md
->disk
->major
= _major
;
1941 md
->disk
->first_minor
= minor
;
1942 md
->disk
->fops
= &dm_blk_dops
;
1943 md
->disk
->queue
= md
->queue
;
1944 md
->disk
->private_data
= md
;
1945 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
1947 format_dev_t(md
->name
, MKDEV(_major
, minor
));
1949 md
->wq
= alloc_workqueue("kdmflush",
1950 WQ_NON_REENTRANT
| WQ_MEM_RECLAIM
, 0);
1954 md
->bdev
= bdget_disk(md
->disk
, 0);
1958 bio_init(&md
->flush_bio
);
1959 md
->flush_bio
.bi_bdev
= md
->bdev
;
1960 md
->flush_bio
.bi_rw
= WRITE_FLUSH
;
1962 /* Populate the mapping, nobody knows we exist yet */
1963 spin_lock(&_minor_lock
);
1964 old_md
= idr_replace(&_minor_idr
, md
, minor
);
1965 spin_unlock(&_minor_lock
);
1967 BUG_ON(old_md
!= MINOR_ALLOCED
);
1972 destroy_workqueue(md
->wq
);
1974 del_gendisk(md
->disk
);
1977 blk_cleanup_queue(md
->queue
);
1979 cleanup_srcu_struct(&md
->io_barrier
);
1983 module_put(THIS_MODULE
);
1989 static void unlock_fs(struct mapped_device
*md
);
1991 static void free_dev(struct mapped_device
*md
)
1993 int minor
= MINOR(disk_devt(md
->disk
));
1997 destroy_workqueue(md
->wq
);
1999 mempool_destroy(md
->io_pool
);
2001 bioset_free(md
->bs
);
2002 blk_integrity_unregister(md
->disk
);
2003 del_gendisk(md
->disk
);
2004 cleanup_srcu_struct(&md
->io_barrier
);
2007 spin_lock(&_minor_lock
);
2008 md
->disk
->private_data
= NULL
;
2009 spin_unlock(&_minor_lock
);
2012 blk_cleanup_queue(md
->queue
);
2013 module_put(THIS_MODULE
);
2017 static void __bind_mempools(struct mapped_device
*md
, struct dm_table
*t
)
2019 struct dm_md_mempools
*p
= dm_table_get_md_mempools(t
);
2021 if (md
->io_pool
&& md
->bs
) {
2022 /* The md already has necessary mempools. */
2023 if (dm_table_get_type(t
) == DM_TYPE_BIO_BASED
) {
2025 * Reload bioset because front_pad may have changed
2026 * because a different table was loaded.
2028 bioset_free(md
->bs
);
2031 } else if (dm_table_get_type(t
) == DM_TYPE_REQUEST_BASED
) {
2033 * There's no need to reload with request-based dm
2034 * because the size of front_pad doesn't change.
2035 * Note for future: If you are to reload bioset,
2036 * prep-ed requests in the queue may refer
2037 * to bio from the old bioset, so you must walk
2038 * through the queue to unprep.
2044 BUG_ON(!p
|| md
->io_pool
|| md
->bs
);
2046 md
->io_pool
= p
->io_pool
;
2052 /* mempool bind completed, now no need any mempools in the table */
2053 dm_table_free_md_mempools(t
);
2057 * Bind a table to the device.
2059 static void event_callback(void *context
)
2061 unsigned long flags
;
2063 struct mapped_device
*md
= (struct mapped_device
*) context
;
2065 spin_lock_irqsave(&md
->uevent_lock
, flags
);
2066 list_splice_init(&md
->uevent_list
, &uevents
);
2067 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
2069 dm_send_uevents(&uevents
, &disk_to_dev(md
->disk
)->kobj
);
2071 atomic_inc(&md
->event_nr
);
2072 wake_up(&md
->eventq
);
2076 * Protected by md->suspend_lock obtained by dm_swap_table().
2078 static void __set_size(struct mapped_device
*md
, sector_t size
)
2080 set_capacity(md
->disk
, size
);
2082 i_size_write(md
->bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
2086 * Return 1 if the queue has a compulsory merge_bvec_fn function.
2088 * If this function returns 0, then the device is either a non-dm
2089 * device without a merge_bvec_fn, or it is a dm device that is
2090 * able to split any bios it receives that are too big.
2092 int dm_queue_merge_is_compulsory(struct request_queue
*q
)
2094 struct mapped_device
*dev_md
;
2096 if (!q
->merge_bvec_fn
)
2099 if (q
->make_request_fn
== dm_request
) {
2100 dev_md
= q
->queuedata
;
2101 if (test_bit(DMF_MERGE_IS_OPTIONAL
, &dev_md
->flags
))
2108 static int dm_device_merge_is_compulsory(struct dm_target
*ti
,
2109 struct dm_dev
*dev
, sector_t start
,
2110 sector_t len
, void *data
)
2112 struct block_device
*bdev
= dev
->bdev
;
2113 struct request_queue
*q
= bdev_get_queue(bdev
);
2115 return dm_queue_merge_is_compulsory(q
);
2119 * Return 1 if it is acceptable to ignore merge_bvec_fn based
2120 * on the properties of the underlying devices.
2122 static int dm_table_merge_is_optional(struct dm_table
*table
)
2125 struct dm_target
*ti
;
2127 while (i
< dm_table_get_num_targets(table
)) {
2128 ti
= dm_table_get_target(table
, i
++);
2130 if (ti
->type
->iterate_devices
&&
2131 ti
->type
->iterate_devices(ti
, dm_device_merge_is_compulsory
, NULL
))
2139 * Returns old map, which caller must destroy.
2141 static struct dm_table
*__bind(struct mapped_device
*md
, struct dm_table
*t
,
2142 struct queue_limits
*limits
)
2144 struct dm_table
*old_map
;
2145 struct request_queue
*q
= md
->queue
;
2147 int merge_is_optional
;
2149 size
= dm_table_get_size(t
);
2152 * Wipe any geometry if the size of the table changed.
2154 if (size
!= get_capacity(md
->disk
))
2155 memset(&md
->geometry
, 0, sizeof(md
->geometry
));
2157 __set_size(md
, size
);
2159 dm_table_event_callback(t
, event_callback
, md
);
2162 * The queue hasn't been stopped yet, if the old table type wasn't
2163 * for request-based during suspension. So stop it to prevent
2164 * I/O mapping before resume.
2165 * This must be done before setting the queue restrictions,
2166 * because request-based dm may be run just after the setting.
2168 if (dm_table_request_based(t
) && !blk_queue_stopped(q
))
2171 __bind_mempools(md
, t
);
2173 merge_is_optional
= dm_table_merge_is_optional(t
);
2176 rcu_assign_pointer(md
->map
, t
);
2177 md
->immutable_target_type
= dm_table_get_immutable_target_type(t
);
2179 dm_table_set_restrictions(t
, q
, limits
);
2180 if (merge_is_optional
)
2181 set_bit(DMF_MERGE_IS_OPTIONAL
, &md
->flags
);
2183 clear_bit(DMF_MERGE_IS_OPTIONAL
, &md
->flags
);
2190 * Returns unbound table for the caller to free.
2192 static struct dm_table
*__unbind(struct mapped_device
*md
)
2194 struct dm_table
*map
= md
->map
;
2199 dm_table_event_callback(map
, NULL
, NULL
);
2200 rcu_assign_pointer(md
->map
, NULL
);
2207 * Constructor for a new device.
2209 int dm_create(int minor
, struct mapped_device
**result
)
2211 struct mapped_device
*md
;
2213 md
= alloc_dev(minor
);
2224 * Functions to manage md->type.
2225 * All are required to hold md->type_lock.
2227 void dm_lock_md_type(struct mapped_device
*md
)
2229 mutex_lock(&md
->type_lock
);
2232 void dm_unlock_md_type(struct mapped_device
*md
)
2234 mutex_unlock(&md
->type_lock
);
2237 void dm_set_md_type(struct mapped_device
*md
, unsigned type
)
2242 unsigned dm_get_md_type(struct mapped_device
*md
)
2247 struct target_type
*dm_get_immutable_target_type(struct mapped_device
*md
)
2249 return md
->immutable_target_type
;
2253 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2255 static int dm_init_request_based_queue(struct mapped_device
*md
)
2257 struct request_queue
*q
= NULL
;
2259 if (md
->queue
->elevator
)
2262 /* Fully initialize the queue */
2263 q
= blk_init_allocated_queue(md
->queue
, dm_request_fn
, NULL
);
2268 dm_init_md_queue(md
);
2269 blk_queue_softirq_done(md
->queue
, dm_softirq_done
);
2270 blk_queue_prep_rq(md
->queue
, dm_prep_fn
);
2271 blk_queue_lld_busy(md
->queue
, dm_lld_busy
);
2273 elv_register_queue(md
->queue
);
2279 * Setup the DM device's queue based on md's type
2281 int dm_setup_md_queue(struct mapped_device
*md
)
2283 if ((dm_get_md_type(md
) == DM_TYPE_REQUEST_BASED
) &&
2284 !dm_init_request_based_queue(md
)) {
2285 DMWARN("Cannot initialize queue for request-based mapped device");
2292 static struct mapped_device
*dm_find_md(dev_t dev
)
2294 struct mapped_device
*md
;
2295 unsigned minor
= MINOR(dev
);
2297 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
2300 spin_lock(&_minor_lock
);
2302 md
= idr_find(&_minor_idr
, minor
);
2303 if (md
&& (md
== MINOR_ALLOCED
||
2304 (MINOR(disk_devt(dm_disk(md
))) != minor
) ||
2305 dm_deleting_md(md
) ||
2306 test_bit(DMF_FREEING
, &md
->flags
))) {
2312 spin_unlock(&_minor_lock
);
2317 struct mapped_device
*dm_get_md(dev_t dev
)
2319 struct mapped_device
*md
= dm_find_md(dev
);
2326 EXPORT_SYMBOL_GPL(dm_get_md
);
2328 void *dm_get_mdptr(struct mapped_device
*md
)
2330 return md
->interface_ptr
;
2333 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
2335 md
->interface_ptr
= ptr
;
2338 void dm_get(struct mapped_device
*md
)
2340 atomic_inc(&md
->holders
);
2341 BUG_ON(test_bit(DMF_FREEING
, &md
->flags
));
2344 const char *dm_device_name(struct mapped_device
*md
)
2348 EXPORT_SYMBOL_GPL(dm_device_name
);
2350 static void __dm_destroy(struct mapped_device
*md
, bool wait
)
2352 struct dm_table
*map
;
2357 spin_lock(&_minor_lock
);
2358 map
= dm_get_live_table(md
, &srcu_idx
);
2359 idr_replace(&_minor_idr
, MINOR_ALLOCED
, MINOR(disk_devt(dm_disk(md
))));
2360 set_bit(DMF_FREEING
, &md
->flags
);
2361 spin_unlock(&_minor_lock
);
2363 if (!dm_suspended_md(md
)) {
2364 dm_table_presuspend_targets(map
);
2365 dm_table_postsuspend_targets(map
);
2368 /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
2369 dm_put_live_table(md
, srcu_idx
);
2372 * Rare, but there may be I/O requests still going to complete,
2373 * for example. Wait for all references to disappear.
2374 * No one should increment the reference count of the mapped_device,
2375 * after the mapped_device state becomes DMF_FREEING.
2378 while (atomic_read(&md
->holders
))
2380 else if (atomic_read(&md
->holders
))
2381 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2382 dm_device_name(md
), atomic_read(&md
->holders
));
2385 dm_table_destroy(__unbind(md
));
2389 void dm_destroy(struct mapped_device
*md
)
2391 __dm_destroy(md
, true);
2394 void dm_destroy_immediate(struct mapped_device
*md
)
2396 __dm_destroy(md
, false);
2399 void dm_put(struct mapped_device
*md
)
2401 atomic_dec(&md
->holders
);
2403 EXPORT_SYMBOL_GPL(dm_put
);
2405 static int dm_wait_for_completion(struct mapped_device
*md
, int interruptible
)
2408 DECLARE_WAITQUEUE(wait
, current
);
2410 add_wait_queue(&md
->wait
, &wait
);
2413 set_current_state(interruptible
);
2415 if (!md_in_flight(md
))
2418 if (interruptible
== TASK_INTERRUPTIBLE
&&
2419 signal_pending(current
)) {
2426 set_current_state(TASK_RUNNING
);
2428 remove_wait_queue(&md
->wait
, &wait
);
2434 * Process the deferred bios
2436 static void dm_wq_work(struct work_struct
*work
)
2438 struct mapped_device
*md
= container_of(work
, struct mapped_device
,
2442 struct dm_table
*map
;
2444 map
= dm_get_live_table(md
, &srcu_idx
);
2446 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2447 spin_lock_irq(&md
->deferred_lock
);
2448 c
= bio_list_pop(&md
->deferred
);
2449 spin_unlock_irq(&md
->deferred_lock
);
2454 if (dm_request_based(md
))
2455 generic_make_request(c
);
2457 __split_and_process_bio(md
, map
, c
);
2460 dm_put_live_table(md
, srcu_idx
);
2463 static void dm_queue_flush(struct mapped_device
*md
)
2465 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2466 smp_mb__after_clear_bit();
2467 queue_work(md
->wq
, &md
->work
);
2471 * Swap in a new table, returning the old one for the caller to destroy.
2473 struct dm_table
*dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
2475 struct dm_table
*live_map
= NULL
, *map
= ERR_PTR(-EINVAL
);
2476 struct queue_limits limits
;
2479 mutex_lock(&md
->suspend_lock
);
2481 /* device must be suspended */
2482 if (!dm_suspended_md(md
))
2486 * If the new table has no data devices, retain the existing limits.
2487 * This helps multipath with queue_if_no_path if all paths disappear,
2488 * then new I/O is queued based on these limits, and then some paths
2491 if (dm_table_has_no_data_devices(table
)) {
2492 live_map
= dm_get_live_table_fast(md
);
2494 limits
= md
->queue
->limits
;
2495 dm_put_live_table_fast(md
);
2499 r
= dm_calculate_queue_limits(table
, &limits
);
2506 map
= __bind(md
, table
, &limits
);
2509 mutex_unlock(&md
->suspend_lock
);
2514 * Functions to lock and unlock any filesystem running on the
2517 static int lock_fs(struct mapped_device
*md
)
2521 WARN_ON(md
->frozen_sb
);
2523 md
->frozen_sb
= freeze_bdev(md
->bdev
);
2524 if (IS_ERR(md
->frozen_sb
)) {
2525 r
= PTR_ERR(md
->frozen_sb
);
2526 md
->frozen_sb
= NULL
;
2530 set_bit(DMF_FROZEN
, &md
->flags
);
2535 static void unlock_fs(struct mapped_device
*md
)
2537 if (!test_bit(DMF_FROZEN
, &md
->flags
))
2540 thaw_bdev(md
->bdev
, md
->frozen_sb
);
2541 md
->frozen_sb
= NULL
;
2542 clear_bit(DMF_FROZEN
, &md
->flags
);
2546 * We need to be able to change a mapping table under a mounted
2547 * filesystem. For example we might want to move some data in
2548 * the background. Before the table can be swapped with
2549 * dm_bind_table, dm_suspend must be called to flush any in
2550 * flight bios and ensure that any further io gets deferred.
2553 * Suspend mechanism in request-based dm.
2555 * 1. Flush all I/Os by lock_fs() if needed.
2556 * 2. Stop dispatching any I/O by stopping the request_queue.
2557 * 3. Wait for all in-flight I/Os to be completed or requeued.
2559 * To abort suspend, start the request_queue.
2561 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
2563 struct dm_table
*map
= NULL
;
2565 int do_lockfs
= suspend_flags
& DM_SUSPEND_LOCKFS_FLAG
? 1 : 0;
2566 int noflush
= suspend_flags
& DM_SUSPEND_NOFLUSH_FLAG
? 1 : 0;
2568 mutex_lock(&md
->suspend_lock
);
2570 if (dm_suspended_md(md
)) {
2578 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2579 * This flag is cleared before dm_suspend returns.
2582 set_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
2584 /* This does not get reverted if there's an error later. */
2585 dm_table_presuspend_targets(map
);
2588 * Flush I/O to the device.
2589 * Any I/O submitted after lock_fs() may not be flushed.
2590 * noflush takes precedence over do_lockfs.
2591 * (lock_fs() flushes I/Os and waits for them to complete.)
2593 if (!noflush
&& do_lockfs
) {
2600 * Here we must make sure that no processes are submitting requests
2601 * to target drivers i.e. no one may be executing
2602 * __split_and_process_bio. This is called from dm_request and
2605 * To get all processes out of __split_and_process_bio in dm_request,
2606 * we take the write lock. To prevent any process from reentering
2607 * __split_and_process_bio from dm_request and quiesce the thread
2608 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
2609 * flush_workqueue(md->wq).
2611 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2612 synchronize_srcu(&md
->io_barrier
);
2615 * Stop md->queue before flushing md->wq in case request-based
2616 * dm defers requests to md->wq from md->queue.
2618 if (dm_request_based(md
))
2619 stop_queue(md
->queue
);
2621 flush_workqueue(md
->wq
);
2624 * At this point no more requests are entering target request routines.
2625 * We call dm_wait_for_completion to wait for all existing requests
2628 r
= dm_wait_for_completion(md
, TASK_INTERRUPTIBLE
);
2631 clear_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
2632 synchronize_srcu(&md
->io_barrier
);
2634 /* were we interrupted ? */
2638 if (dm_request_based(md
))
2639 start_queue(md
->queue
);
2642 goto out_unlock
; /* pushback list is already flushed, so skip flush */
2646 * If dm_wait_for_completion returned 0, the device is completely
2647 * quiescent now. There is no request-processing activity. All new
2648 * requests are being added to md->deferred list.
2651 set_bit(DMF_SUSPENDED
, &md
->flags
);
2653 dm_table_postsuspend_targets(map
);
2656 mutex_unlock(&md
->suspend_lock
);
2660 int dm_resume(struct mapped_device
*md
)
2663 struct dm_table
*map
= NULL
;
2665 mutex_lock(&md
->suspend_lock
);
2666 if (!dm_suspended_md(md
))
2670 if (!map
|| !dm_table_get_size(map
))
2673 r
= dm_table_resume_targets(map
);
2680 * Flushing deferred I/Os must be done after targets are resumed
2681 * so that mapping of targets can work correctly.
2682 * Request-based dm is queueing the deferred I/Os in its request_queue.
2684 if (dm_request_based(md
))
2685 start_queue(md
->queue
);
2689 clear_bit(DMF_SUSPENDED
, &md
->flags
);
2693 mutex_unlock(&md
->suspend_lock
);
2698 /*-----------------------------------------------------------------
2699 * Event notification.
2700 *---------------------------------------------------------------*/
2701 int dm_kobject_uevent(struct mapped_device
*md
, enum kobject_action action
,
2704 char udev_cookie
[DM_COOKIE_LENGTH
];
2705 char *envp
[] = { udev_cookie
, NULL
};
2708 return kobject_uevent(&disk_to_dev(md
->disk
)->kobj
, action
);
2710 snprintf(udev_cookie
, DM_COOKIE_LENGTH
, "%s=%u",
2711 DM_COOKIE_ENV_VAR_NAME
, cookie
);
2712 return kobject_uevent_env(&disk_to_dev(md
->disk
)->kobj
,
2717 uint32_t dm_next_uevent_seq(struct mapped_device
*md
)
2719 return atomic_add_return(1, &md
->uevent_seq
);
2722 uint32_t dm_get_event_nr(struct mapped_device
*md
)
2724 return atomic_read(&md
->event_nr
);
2727 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
2729 return wait_event_interruptible(md
->eventq
,
2730 (event_nr
!= atomic_read(&md
->event_nr
)));
2733 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
)
2735 unsigned long flags
;
2737 spin_lock_irqsave(&md
->uevent_lock
, flags
);
2738 list_add(elist
, &md
->uevent_list
);
2739 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
2743 * The gendisk is only valid as long as you have a reference
2746 struct gendisk
*dm_disk(struct mapped_device
*md
)
2751 struct kobject
*dm_kobject(struct mapped_device
*md
)
2757 * struct mapped_device should not be exported outside of dm.c
2758 * so use this check to verify that kobj is part of md structure
2760 struct mapped_device
*dm_get_from_kobject(struct kobject
*kobj
)
2762 struct mapped_device
*md
;
2764 md
= container_of(kobj
, struct mapped_device
, kobj
);
2765 if (&md
->kobj
!= kobj
)
2768 if (test_bit(DMF_FREEING
, &md
->flags
) ||
2776 int dm_suspended_md(struct mapped_device
*md
)
2778 return test_bit(DMF_SUSPENDED
, &md
->flags
);
2781 int dm_suspended(struct dm_target
*ti
)
2783 return dm_suspended_md(dm_table_get_md(ti
->table
));
2785 EXPORT_SYMBOL_GPL(dm_suspended
);
2787 int dm_noflush_suspending(struct dm_target
*ti
)
2789 return __noflush_suspending(dm_table_get_md(ti
->table
));
2791 EXPORT_SYMBOL_GPL(dm_noflush_suspending
);
2793 struct dm_md_mempools
*dm_alloc_md_mempools(unsigned type
, unsigned integrity
, unsigned per_bio_data_size
)
2795 struct dm_md_mempools
*pools
= kzalloc(sizeof(*pools
), GFP_KERNEL
);
2796 struct kmem_cache
*cachep
;
2797 unsigned int pool_size
;
2798 unsigned int front_pad
;
2803 if (type
== DM_TYPE_BIO_BASED
) {
2806 front_pad
= roundup(per_bio_data_size
, __alignof__(struct dm_target_io
)) + offsetof(struct dm_target_io
, clone
);
2807 } else if (type
== DM_TYPE_REQUEST_BASED
) {
2808 cachep
= _rq_tio_cache
;
2809 pool_size
= MIN_IOS
;
2810 front_pad
= offsetof(struct dm_rq_clone_bio_info
, clone
);
2811 /* per_bio_data_size is not used. See __bind_mempools(). */
2812 WARN_ON(per_bio_data_size
!= 0);
2816 pools
->io_pool
= mempool_create_slab_pool(MIN_IOS
, cachep
);
2817 if (!pools
->io_pool
)
2820 pools
->bs
= bioset_create(pool_size
, front_pad
);
2824 if (integrity
&& bioset_integrity_create(pools
->bs
, pool_size
))
2830 dm_free_md_mempools(pools
);
2835 void dm_free_md_mempools(struct dm_md_mempools
*pools
)
2841 mempool_destroy(pools
->io_pool
);
2844 bioset_free(pools
->bs
);
2849 static const struct block_device_operations dm_blk_dops
= {
2850 .open
= dm_blk_open
,
2851 .release
= dm_blk_close
,
2852 .ioctl
= dm_blk_ioctl
,
2853 .getgeo
= dm_blk_getgeo
,
2854 .owner
= THIS_MODULE
2857 EXPORT_SYMBOL(dm_get_mapinfo
);
2862 module_init(dm_init
);
2863 module_exit(dm_exit
);
2865 module_param(major
, uint
, 0);
2866 MODULE_PARM_DESC(major
, "The major number of the device mapper");
2867 MODULE_DESCRIPTION(DM_NAME
" driver");
2868 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2869 MODULE_LICENSE("GPL");