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>
22 #include <linux/wait.h>
23 #include <linux/kthread.h>
24 #include <linux/ktime.h>
25 #include <linux/elevator.h> /* for rq_end_sector() */
26 #include <linux/blk-mq.h>
28 #include <trace/events/block.h>
30 #define DM_MSG_PREFIX "core"
34 * ratelimit state to be used in DMXXX_LIMIT().
36 DEFINE_RATELIMIT_STATE(dm_ratelimit_state
,
37 DEFAULT_RATELIMIT_INTERVAL
,
38 DEFAULT_RATELIMIT_BURST
);
39 EXPORT_SYMBOL(dm_ratelimit_state
);
43 * Cookies are numeric values sent with CHANGE and REMOVE
44 * uevents while resuming, removing or renaming the device.
46 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
47 #define DM_COOKIE_LENGTH 24
49 static const char *_name
= DM_NAME
;
51 static unsigned int major
= 0;
52 static unsigned int _major
= 0;
54 static DEFINE_IDR(_minor_idr
);
56 static DEFINE_SPINLOCK(_minor_lock
);
58 static void do_deferred_remove(struct work_struct
*w
);
60 static DECLARE_WORK(deferred_remove_work
, do_deferred_remove
);
62 static struct workqueue_struct
*deferred_remove_workqueue
;
66 * One of these is allocated per bio.
69 struct mapped_device
*md
;
73 unsigned long start_time
;
74 spinlock_t endio_lock
;
75 struct dm_stats_aux stats_aux
;
79 * For request-based dm.
80 * One of these is allocated per request.
82 struct dm_rq_target_io
{
83 struct mapped_device
*md
;
85 struct request
*orig
, *clone
;
86 struct kthread_work work
;
89 struct dm_stats_aux stats_aux
;
90 unsigned long duration_jiffies
;
95 * For request-based dm - the bio clones we allocate are embedded in these
98 * We allocate these with bio_alloc_bioset, using the front_pad parameter when
99 * the bioset is created - this means the bio has to come at the end of the
102 struct dm_rq_clone_bio_info
{
104 struct dm_rq_target_io
*tio
;
108 union map_info
*dm_get_rq_mapinfo(struct request
*rq
)
110 if (rq
&& rq
->end_io_data
)
111 return &((struct dm_rq_target_io
*)rq
->end_io_data
)->info
;
114 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo
);
116 #define MINOR_ALLOCED ((void *)-1)
119 * Bits for the md->flags field.
121 #define DMF_BLOCK_IO_FOR_SUSPEND 0
122 #define DMF_SUSPENDED 1
124 #define DMF_FREEING 3
125 #define DMF_DELETING 4
126 #define DMF_NOFLUSH_SUSPENDING 5
127 #define DMF_DEFERRED_REMOVE 6
128 #define DMF_SUSPENDED_INTERNALLY 7
131 * A dummy definition to make RCU happy.
132 * struct dm_table should never be dereferenced in this file.
139 * Work processed by per-device workqueue.
141 struct mapped_device
{
142 struct srcu_struct io_barrier
;
143 struct mutex suspend_lock
;
148 * The current mapping.
149 * Use dm_get_live_table{_fast} or take suspend_lock for
152 struct dm_table __rcu
*map
;
154 struct list_head table_devices
;
155 struct mutex table_devices_lock
;
159 struct request_queue
*queue
;
161 /* Protect queue and type against concurrent access. */
162 struct mutex type_lock
;
164 struct target_type
*immutable_target_type
;
166 struct gendisk
*disk
;
172 * A list of ios that arrived while we were suspended.
175 wait_queue_head_t wait
;
176 struct work_struct work
;
177 struct bio_list deferred
;
178 spinlock_t deferred_lock
;
181 * Processing queue (flush)
183 struct workqueue_struct
*wq
;
186 * io objects are allocated from here.
197 wait_queue_head_t eventq
;
199 struct list_head uevent_list
;
200 spinlock_t uevent_lock
; /* Protect access to uevent_list */
203 * freeze/thaw support require holding onto a super block
205 struct super_block
*frozen_sb
;
206 struct block_device
*bdev
;
208 /* forced geometry settings */
209 struct hd_geometry geometry
;
211 /* kobject and completion */
212 struct dm_kobject_holder kobj_holder
;
214 /* zero-length flush that will be cloned and submitted to targets */
215 struct bio flush_bio
;
217 /* the number of internal suspends */
218 unsigned internal_suspend_count
;
220 struct dm_stats stats
;
222 struct kthread_worker kworker
;
223 struct task_struct
*kworker_task
;
225 /* for request-based merge heuristic in dm_request_fn() */
226 unsigned seq_rq_merge_deadline_usecs
;
228 sector_t last_rq_pos
;
229 ktime_t last_rq_start_time
;
231 /* for blk-mq request-based DM support */
232 struct blk_mq_tag_set tag_set
;
236 #ifdef CONFIG_DM_MQ_DEFAULT
237 static bool use_blk_mq
= true;
239 static bool use_blk_mq
= false;
242 bool dm_use_blk_mq(struct mapped_device
*md
)
244 return md
->use_blk_mq
;
248 * For mempools pre-allocation at the table loading time.
250 struct dm_md_mempools
{
256 struct table_device
{
257 struct list_head list
;
259 struct dm_dev dm_dev
;
262 #define RESERVED_BIO_BASED_IOS 16
263 #define RESERVED_REQUEST_BASED_IOS 256
264 #define RESERVED_MAX_IOS 1024
265 static struct kmem_cache
*_io_cache
;
266 static struct kmem_cache
*_rq_tio_cache
;
267 static struct kmem_cache
*_rq_cache
;
270 * Bio-based DM's mempools' reserved IOs set by the user.
272 static unsigned reserved_bio_based_ios
= RESERVED_BIO_BASED_IOS
;
275 * Request-based DM's mempools' reserved IOs set by the user.
277 static unsigned reserved_rq_based_ios
= RESERVED_REQUEST_BASED_IOS
;
279 static unsigned __dm_get_module_param(unsigned *module_param
,
280 unsigned def
, unsigned max
)
282 unsigned param
= ACCESS_ONCE(*module_param
);
283 unsigned modified_param
= 0;
286 modified_param
= def
;
287 else if (param
> max
)
288 modified_param
= max
;
290 if (modified_param
) {
291 (void)cmpxchg(module_param
, param
, modified_param
);
292 param
= modified_param
;
298 unsigned dm_get_reserved_bio_based_ios(void)
300 return __dm_get_module_param(&reserved_bio_based_ios
,
301 RESERVED_BIO_BASED_IOS
, RESERVED_MAX_IOS
);
303 EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios
);
305 unsigned dm_get_reserved_rq_based_ios(void)
307 return __dm_get_module_param(&reserved_rq_based_ios
,
308 RESERVED_REQUEST_BASED_IOS
, RESERVED_MAX_IOS
);
310 EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios
);
312 static int __init
local_init(void)
316 /* allocate a slab for the dm_ios */
317 _io_cache
= KMEM_CACHE(dm_io
, 0);
321 _rq_tio_cache
= KMEM_CACHE(dm_rq_target_io
, 0);
323 goto out_free_io_cache
;
325 _rq_cache
= kmem_cache_create("dm_clone_request", sizeof(struct request
),
326 __alignof__(struct request
), 0, NULL
);
328 goto out_free_rq_tio_cache
;
330 r
= dm_uevent_init();
332 goto out_free_rq_cache
;
334 deferred_remove_workqueue
= alloc_workqueue("kdmremove", WQ_UNBOUND
, 1);
335 if (!deferred_remove_workqueue
) {
337 goto out_uevent_exit
;
341 r
= register_blkdev(_major
, _name
);
343 goto out_free_workqueue
;
351 destroy_workqueue(deferred_remove_workqueue
);
355 kmem_cache_destroy(_rq_cache
);
356 out_free_rq_tio_cache
:
357 kmem_cache_destroy(_rq_tio_cache
);
359 kmem_cache_destroy(_io_cache
);
364 static void local_exit(void)
366 flush_scheduled_work();
367 destroy_workqueue(deferred_remove_workqueue
);
369 kmem_cache_destroy(_rq_cache
);
370 kmem_cache_destroy(_rq_tio_cache
);
371 kmem_cache_destroy(_io_cache
);
372 unregister_blkdev(_major
, _name
);
377 DMINFO("cleaned up");
380 static int (*_inits
[])(void) __initdata
= {
391 static void (*_exits
[])(void) = {
402 static int __init
dm_init(void)
404 const int count
= ARRAY_SIZE(_inits
);
408 for (i
= 0; i
< count
; i
++) {
423 static void __exit
dm_exit(void)
425 int i
= ARRAY_SIZE(_exits
);
431 * Should be empty by this point.
433 idr_destroy(&_minor_idr
);
437 * Block device functions
439 int dm_deleting_md(struct mapped_device
*md
)
441 return test_bit(DMF_DELETING
, &md
->flags
);
444 static int dm_blk_open(struct block_device
*bdev
, fmode_t mode
)
446 struct mapped_device
*md
;
448 spin_lock(&_minor_lock
);
450 md
= bdev
->bd_disk
->private_data
;
454 if (test_bit(DMF_FREEING
, &md
->flags
) ||
455 dm_deleting_md(md
)) {
461 atomic_inc(&md
->open_count
);
463 spin_unlock(&_minor_lock
);
465 return md
? 0 : -ENXIO
;
468 static void dm_blk_close(struct gendisk
*disk
, fmode_t mode
)
470 struct mapped_device
*md
;
472 spin_lock(&_minor_lock
);
474 md
= disk
->private_data
;
478 if (atomic_dec_and_test(&md
->open_count
) &&
479 (test_bit(DMF_DEFERRED_REMOVE
, &md
->flags
)))
480 queue_work(deferred_remove_workqueue
, &deferred_remove_work
);
484 spin_unlock(&_minor_lock
);
487 int dm_open_count(struct mapped_device
*md
)
489 return atomic_read(&md
->open_count
);
493 * Guarantees nothing is using the device before it's deleted.
495 int dm_lock_for_deletion(struct mapped_device
*md
, bool mark_deferred
, bool only_deferred
)
499 spin_lock(&_minor_lock
);
501 if (dm_open_count(md
)) {
504 set_bit(DMF_DEFERRED_REMOVE
, &md
->flags
);
505 } else if (only_deferred
&& !test_bit(DMF_DEFERRED_REMOVE
, &md
->flags
))
508 set_bit(DMF_DELETING
, &md
->flags
);
510 spin_unlock(&_minor_lock
);
515 int dm_cancel_deferred_remove(struct mapped_device
*md
)
519 spin_lock(&_minor_lock
);
521 if (test_bit(DMF_DELETING
, &md
->flags
))
524 clear_bit(DMF_DEFERRED_REMOVE
, &md
->flags
);
526 spin_unlock(&_minor_lock
);
531 static void do_deferred_remove(struct work_struct
*w
)
533 dm_deferred_remove();
536 sector_t
dm_get_size(struct mapped_device
*md
)
538 return get_capacity(md
->disk
);
541 struct request_queue
*dm_get_md_queue(struct mapped_device
*md
)
546 struct dm_stats
*dm_get_stats(struct mapped_device
*md
)
551 static int dm_blk_getgeo(struct block_device
*bdev
, struct hd_geometry
*geo
)
553 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
555 return dm_get_geometry(md
, geo
);
558 static int dm_blk_ioctl(struct block_device
*bdev
, fmode_t mode
,
559 unsigned int cmd
, unsigned long arg
)
561 struct mapped_device
*md
= bdev
->bd_disk
->private_data
;
563 struct dm_table
*map
;
564 struct dm_target
*tgt
;
568 map
= dm_get_live_table(md
, &srcu_idx
);
570 if (!map
|| !dm_table_get_size(map
))
573 /* We only support devices that have a single target */
574 if (dm_table_get_num_targets(map
) != 1)
577 tgt
= dm_table_get_target(map
, 0);
578 if (!tgt
->type
->ioctl
)
581 if (dm_suspended_md(md
)) {
586 r
= tgt
->type
->ioctl(tgt
, cmd
, arg
);
589 dm_put_live_table(md
, srcu_idx
);
591 if (r
== -ENOTCONN
) {
599 static struct dm_io
*alloc_io(struct mapped_device
*md
)
601 return mempool_alloc(md
->io_pool
, GFP_NOIO
);
604 static void free_io(struct mapped_device
*md
, struct dm_io
*io
)
606 mempool_free(io
, md
->io_pool
);
609 static void free_tio(struct mapped_device
*md
, struct dm_target_io
*tio
)
611 bio_put(&tio
->clone
);
614 static struct dm_rq_target_io
*alloc_rq_tio(struct mapped_device
*md
,
617 return mempool_alloc(md
->io_pool
, gfp_mask
);
620 static void free_rq_tio(struct dm_rq_target_io
*tio
)
622 mempool_free(tio
, tio
->md
->io_pool
);
625 static struct request
*alloc_clone_request(struct mapped_device
*md
,
628 return mempool_alloc(md
->rq_pool
, gfp_mask
);
631 static void free_clone_request(struct mapped_device
*md
, struct request
*rq
)
633 mempool_free(rq
, md
->rq_pool
);
636 static int md_in_flight(struct mapped_device
*md
)
638 return atomic_read(&md
->pending
[READ
]) +
639 atomic_read(&md
->pending
[WRITE
]);
642 static void start_io_acct(struct dm_io
*io
)
644 struct mapped_device
*md
= io
->md
;
645 struct bio
*bio
= io
->bio
;
647 int rw
= bio_data_dir(bio
);
649 io
->start_time
= jiffies
;
651 cpu
= part_stat_lock();
652 part_round_stats(cpu
, &dm_disk(md
)->part0
);
654 atomic_set(&dm_disk(md
)->part0
.in_flight
[rw
],
655 atomic_inc_return(&md
->pending
[rw
]));
657 if (unlikely(dm_stats_used(&md
->stats
)))
658 dm_stats_account_io(&md
->stats
, bio
->bi_rw
, bio
->bi_iter
.bi_sector
,
659 bio_sectors(bio
), false, 0, &io
->stats_aux
);
662 static void end_io_acct(struct dm_io
*io
)
664 struct mapped_device
*md
= io
->md
;
665 struct bio
*bio
= io
->bio
;
666 unsigned long duration
= jiffies
- io
->start_time
;
668 int rw
= bio_data_dir(bio
);
670 generic_end_io_acct(rw
, &dm_disk(md
)->part0
, io
->start_time
);
672 if (unlikely(dm_stats_used(&md
->stats
)))
673 dm_stats_account_io(&md
->stats
, bio
->bi_rw
, bio
->bi_iter
.bi_sector
,
674 bio_sectors(bio
), true, duration
, &io
->stats_aux
);
677 * After this is decremented the bio must not be touched if it is
680 pending
= atomic_dec_return(&md
->pending
[rw
]);
681 atomic_set(&dm_disk(md
)->part0
.in_flight
[rw
], pending
);
682 pending
+= atomic_read(&md
->pending
[rw
^0x1]);
684 /* nudge anyone waiting on suspend queue */
690 * Add the bio to the list of deferred io.
692 static void queue_io(struct mapped_device
*md
, struct bio
*bio
)
696 spin_lock_irqsave(&md
->deferred_lock
, flags
);
697 bio_list_add(&md
->deferred
, bio
);
698 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
699 queue_work(md
->wq
, &md
->work
);
703 * Everyone (including functions in this file), should use this
704 * function to access the md->map field, and make sure they call
705 * dm_put_live_table() when finished.
707 struct dm_table
*dm_get_live_table(struct mapped_device
*md
, int *srcu_idx
) __acquires(md
->io_barrier
)
709 *srcu_idx
= srcu_read_lock(&md
->io_barrier
);
711 return srcu_dereference(md
->map
, &md
->io_barrier
);
714 void dm_put_live_table(struct mapped_device
*md
, int srcu_idx
) __releases(md
->io_barrier
)
716 srcu_read_unlock(&md
->io_barrier
, srcu_idx
);
719 void dm_sync_table(struct mapped_device
*md
)
721 synchronize_srcu(&md
->io_barrier
);
722 synchronize_rcu_expedited();
726 * A fast alternative to dm_get_live_table/dm_put_live_table.
727 * The caller must not block between these two functions.
729 static struct dm_table
*dm_get_live_table_fast(struct mapped_device
*md
) __acquires(RCU
)
732 return rcu_dereference(md
->map
);
735 static void dm_put_live_table_fast(struct mapped_device
*md
) __releases(RCU
)
741 * Open a table device so we can use it as a map destination.
743 static int open_table_device(struct table_device
*td
, dev_t dev
,
744 struct mapped_device
*md
)
746 static char *_claim_ptr
= "I belong to device-mapper";
747 struct block_device
*bdev
;
751 BUG_ON(td
->dm_dev
.bdev
);
753 bdev
= blkdev_get_by_dev(dev
, td
->dm_dev
.mode
| FMODE_EXCL
, _claim_ptr
);
755 return PTR_ERR(bdev
);
757 r
= bd_link_disk_holder(bdev
, dm_disk(md
));
759 blkdev_put(bdev
, td
->dm_dev
.mode
| FMODE_EXCL
);
763 td
->dm_dev
.bdev
= bdev
;
768 * Close a table device that we've been using.
770 static void close_table_device(struct table_device
*td
, struct mapped_device
*md
)
772 if (!td
->dm_dev
.bdev
)
775 bd_unlink_disk_holder(td
->dm_dev
.bdev
, dm_disk(md
));
776 blkdev_put(td
->dm_dev
.bdev
, td
->dm_dev
.mode
| FMODE_EXCL
);
777 td
->dm_dev
.bdev
= NULL
;
780 static struct table_device
*find_table_device(struct list_head
*l
, dev_t dev
,
782 struct table_device
*td
;
784 list_for_each_entry(td
, l
, list
)
785 if (td
->dm_dev
.bdev
->bd_dev
== dev
&& td
->dm_dev
.mode
== mode
)
791 int dm_get_table_device(struct mapped_device
*md
, dev_t dev
, fmode_t mode
,
792 struct dm_dev
**result
) {
794 struct table_device
*td
;
796 mutex_lock(&md
->table_devices_lock
);
797 td
= find_table_device(&md
->table_devices
, dev
, mode
);
799 td
= kmalloc(sizeof(*td
), GFP_KERNEL
);
801 mutex_unlock(&md
->table_devices_lock
);
805 td
->dm_dev
.mode
= mode
;
806 td
->dm_dev
.bdev
= NULL
;
808 if ((r
= open_table_device(td
, dev
, md
))) {
809 mutex_unlock(&md
->table_devices_lock
);
814 format_dev_t(td
->dm_dev
.name
, dev
);
816 atomic_set(&td
->count
, 0);
817 list_add(&td
->list
, &md
->table_devices
);
819 atomic_inc(&td
->count
);
820 mutex_unlock(&md
->table_devices_lock
);
822 *result
= &td
->dm_dev
;
825 EXPORT_SYMBOL_GPL(dm_get_table_device
);
827 void dm_put_table_device(struct mapped_device
*md
, struct dm_dev
*d
)
829 struct table_device
*td
= container_of(d
, struct table_device
, dm_dev
);
831 mutex_lock(&md
->table_devices_lock
);
832 if (atomic_dec_and_test(&td
->count
)) {
833 close_table_device(td
, md
);
837 mutex_unlock(&md
->table_devices_lock
);
839 EXPORT_SYMBOL(dm_put_table_device
);
841 static void free_table_devices(struct list_head
*devices
)
843 struct list_head
*tmp
, *next
;
845 list_for_each_safe(tmp
, next
, devices
) {
846 struct table_device
*td
= list_entry(tmp
, struct table_device
, list
);
848 DMWARN("dm_destroy: %s still exists with %d references",
849 td
->dm_dev
.name
, atomic_read(&td
->count
));
855 * Get the geometry associated with a dm device
857 int dm_get_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
865 * Set the geometry of a device.
867 int dm_set_geometry(struct mapped_device
*md
, struct hd_geometry
*geo
)
869 sector_t sz
= (sector_t
)geo
->cylinders
* geo
->heads
* geo
->sectors
;
871 if (geo
->start
> sz
) {
872 DMWARN("Start sector is beyond the geometry limits.");
881 /*-----------------------------------------------------------------
883 * A more elegant soln is in the works that uses the queue
884 * merge fn, unfortunately there are a couple of changes to
885 * the block layer that I want to make for this. So in the
886 * interests of getting something for people to use I give
887 * you this clearly demarcated crap.
888 *---------------------------------------------------------------*/
890 static int __noflush_suspending(struct mapped_device
*md
)
892 return test_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
896 * Decrements the number of outstanding ios that a bio has been
897 * cloned into, completing the original io if necc.
899 static void dec_pending(struct dm_io
*io
, int error
)
904 struct mapped_device
*md
= io
->md
;
906 /* Push-back supersedes any I/O errors */
907 if (unlikely(error
)) {
908 spin_lock_irqsave(&io
->endio_lock
, flags
);
909 if (!(io
->error
> 0 && __noflush_suspending(md
)))
911 spin_unlock_irqrestore(&io
->endio_lock
, flags
);
914 if (atomic_dec_and_test(&io
->io_count
)) {
915 if (io
->error
== DM_ENDIO_REQUEUE
) {
917 * Target requested pushing back the I/O.
919 spin_lock_irqsave(&md
->deferred_lock
, flags
);
920 if (__noflush_suspending(md
))
921 bio_list_add_head(&md
->deferred
, io
->bio
);
923 /* noflush suspend was interrupted. */
925 spin_unlock_irqrestore(&md
->deferred_lock
, flags
);
928 io_error
= io
->error
;
933 if (io_error
== DM_ENDIO_REQUEUE
)
936 if ((bio
->bi_rw
& REQ_FLUSH
) && bio
->bi_iter
.bi_size
) {
938 * Preflush done for flush with data, reissue
941 bio
->bi_rw
&= ~REQ_FLUSH
;
944 /* done with normal IO or empty flush */
945 trace_block_bio_complete(md
->queue
, bio
, io_error
);
946 bio
->bi_error
= io_error
;
952 static void disable_write_same(struct mapped_device
*md
)
954 struct queue_limits
*limits
= dm_get_queue_limits(md
);
956 /* device doesn't really support WRITE SAME, disable it */
957 limits
->max_write_same_sectors
= 0;
960 static void clone_endio(struct bio
*bio
)
962 int error
= bio
->bi_error
;
964 struct dm_target_io
*tio
= container_of(bio
, struct dm_target_io
, clone
);
965 struct dm_io
*io
= tio
->io
;
966 struct mapped_device
*md
= tio
->io
->md
;
967 dm_endio_fn endio
= tio
->ti
->type
->end_io
;
970 r
= endio(tio
->ti
, bio
, error
);
971 if (r
< 0 || r
== DM_ENDIO_REQUEUE
)
973 * error and requeue request are handled
977 else if (r
== DM_ENDIO_INCOMPLETE
)
978 /* The target will handle the io */
981 DMWARN("unimplemented target endio return value: %d", r
);
986 if (unlikely(r
== -EREMOTEIO
&& (bio
->bi_rw
& REQ_WRITE_SAME
) &&
987 !bdev_get_queue(bio
->bi_bdev
)->limits
.max_write_same_sectors
))
988 disable_write_same(md
);
991 dec_pending(io
, error
);
995 * Partial completion handling for request-based dm
997 static void end_clone_bio(struct bio
*clone
)
999 struct dm_rq_clone_bio_info
*info
=
1000 container_of(clone
, struct dm_rq_clone_bio_info
, clone
);
1001 struct dm_rq_target_io
*tio
= info
->tio
;
1002 struct bio
*bio
= info
->orig
;
1003 unsigned int nr_bytes
= info
->orig
->bi_iter
.bi_size
;
1009 * An error has already been detected on the request.
1010 * Once error occurred, just let clone->end_io() handle
1014 else if (bio
->bi_error
) {
1016 * Don't notice the error to the upper layer yet.
1017 * The error handling decision is made by the target driver,
1018 * when the request is completed.
1020 tio
->error
= bio
->bi_error
;
1025 * I/O for the bio successfully completed.
1026 * Notice the data completion to the upper layer.
1030 * bios are processed from the head of the list.
1031 * So the completing bio should always be rq->bio.
1032 * If it's not, something wrong is happening.
1034 if (tio
->orig
->bio
!= bio
)
1035 DMERR("bio completion is going in the middle of the request");
1038 * Update the original request.
1039 * Do not use blk_end_request() here, because it may complete
1040 * the original request before the clone, and break the ordering.
1042 blk_update_request(tio
->orig
, 0, nr_bytes
);
1045 static struct dm_rq_target_io
*tio_from_request(struct request
*rq
)
1047 return (rq
->q
->mq_ops
? blk_mq_rq_to_pdu(rq
) : rq
->special
);
1050 static void rq_end_stats(struct mapped_device
*md
, struct request
*orig
)
1052 if (unlikely(dm_stats_used(&md
->stats
))) {
1053 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
1054 tio
->duration_jiffies
= jiffies
- tio
->duration_jiffies
;
1055 dm_stats_account_io(&md
->stats
, orig
->cmd_flags
, blk_rq_pos(orig
),
1056 tio
->n_sectors
, true, tio
->duration_jiffies
,
1062 * Don't touch any member of the md after calling this function because
1063 * the md may be freed in dm_put() at the end of this function.
1064 * Or do dm_get() before calling this function and dm_put() later.
1066 static void rq_completed(struct mapped_device
*md
, int rw
, bool run_queue
)
1068 atomic_dec(&md
->pending
[rw
]);
1070 /* nudge anyone waiting on suspend queue */
1071 if (!md_in_flight(md
))
1075 * Run this off this callpath, as drivers could invoke end_io while
1076 * inside their request_fn (and holding the queue lock). Calling
1077 * back into ->request_fn() could deadlock attempting to grab the
1081 if (md
->queue
->mq_ops
)
1082 blk_mq_run_hw_queues(md
->queue
, true);
1084 blk_run_queue_async(md
->queue
);
1088 * dm_put() must be at the end of this function. See the comment above
1093 static void free_rq_clone(struct request
*clone
)
1095 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1096 struct mapped_device
*md
= tio
->md
;
1098 blk_rq_unprep_clone(clone
);
1100 if (md
->type
== DM_TYPE_MQ_REQUEST_BASED
)
1101 /* stacked on blk-mq queue(s) */
1102 tio
->ti
->type
->release_clone_rq(clone
);
1103 else if (!md
->queue
->mq_ops
)
1104 /* request_fn queue stacked on request_fn queue(s) */
1105 free_clone_request(md
, clone
);
1107 * NOTE: for the blk-mq queue stacked on request_fn queue(s) case:
1108 * no need to call free_clone_request() because we leverage blk-mq by
1109 * allocating the clone at the end of the blk-mq pdu (see: clone_rq)
1112 if (!md
->queue
->mq_ops
)
1117 * Complete the clone and the original request.
1118 * Must be called without clone's queue lock held,
1119 * see end_clone_request() for more details.
1121 static void dm_end_request(struct request
*clone
, int error
)
1123 int rw
= rq_data_dir(clone
);
1124 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1125 struct mapped_device
*md
= tio
->md
;
1126 struct request
*rq
= tio
->orig
;
1128 if (rq
->cmd_type
== REQ_TYPE_BLOCK_PC
) {
1129 rq
->errors
= clone
->errors
;
1130 rq
->resid_len
= clone
->resid_len
;
1134 * We are using the sense buffer of the original
1136 * So setting the length of the sense data is enough.
1138 rq
->sense_len
= clone
->sense_len
;
1141 free_rq_clone(clone
);
1142 rq_end_stats(md
, rq
);
1144 blk_end_request_all(rq
, error
);
1146 blk_mq_end_request(rq
, error
);
1147 rq_completed(md
, rw
, true);
1150 static void dm_unprep_request(struct request
*rq
)
1152 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
1153 struct request
*clone
= tio
->clone
;
1155 if (!rq
->q
->mq_ops
) {
1157 rq
->cmd_flags
&= ~REQ_DONTPREP
;
1161 free_rq_clone(clone
);
1165 * Requeue the original request of a clone.
1167 static void old_requeue_request(struct request
*rq
)
1169 struct request_queue
*q
= rq
->q
;
1170 unsigned long flags
;
1172 spin_lock_irqsave(q
->queue_lock
, flags
);
1173 blk_requeue_request(q
, rq
);
1174 blk_run_queue_async(q
);
1175 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1178 static void dm_requeue_original_request(struct mapped_device
*md
,
1181 int rw
= rq_data_dir(rq
);
1183 dm_unprep_request(rq
);
1185 rq_end_stats(md
, rq
);
1187 old_requeue_request(rq
);
1189 blk_mq_requeue_request(rq
);
1190 blk_mq_kick_requeue_list(rq
->q
);
1193 rq_completed(md
, rw
, false);
1196 static void old_stop_queue(struct request_queue
*q
)
1198 unsigned long flags
;
1200 if (blk_queue_stopped(q
))
1203 spin_lock_irqsave(q
->queue_lock
, flags
);
1205 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1208 static void stop_queue(struct request_queue
*q
)
1213 blk_mq_stop_hw_queues(q
);
1216 static void old_start_queue(struct request_queue
*q
)
1218 unsigned long flags
;
1220 spin_lock_irqsave(q
->queue_lock
, flags
);
1221 if (blk_queue_stopped(q
))
1223 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1226 static void start_queue(struct request_queue
*q
)
1231 blk_mq_start_stopped_hw_queues(q
, true);
1234 static void dm_done(struct request
*clone
, int error
, bool mapped
)
1237 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1238 dm_request_endio_fn rq_end_io
= NULL
;
1241 rq_end_io
= tio
->ti
->type
->rq_end_io
;
1243 if (mapped
&& rq_end_io
)
1244 r
= rq_end_io(tio
->ti
, clone
, error
, &tio
->info
);
1247 if (unlikely(r
== -EREMOTEIO
&& (clone
->cmd_flags
& REQ_WRITE_SAME
) &&
1248 !clone
->q
->limits
.max_write_same_sectors
))
1249 disable_write_same(tio
->md
);
1252 /* The target wants to complete the I/O */
1253 dm_end_request(clone
, r
);
1254 else if (r
== DM_ENDIO_INCOMPLETE
)
1255 /* The target will handle the I/O */
1257 else if (r
== DM_ENDIO_REQUEUE
)
1258 /* The target wants to requeue the I/O */
1259 dm_requeue_original_request(tio
->md
, tio
->orig
);
1261 DMWARN("unimplemented target endio return value: %d", r
);
1267 * Request completion handler for request-based dm
1269 static void dm_softirq_done(struct request
*rq
)
1272 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
1273 struct request
*clone
= tio
->clone
;
1277 rq_end_stats(tio
->md
, rq
);
1278 rw
= rq_data_dir(rq
);
1279 if (!rq
->q
->mq_ops
) {
1280 blk_end_request_all(rq
, tio
->error
);
1281 rq_completed(tio
->md
, rw
, false);
1284 blk_mq_end_request(rq
, tio
->error
);
1285 rq_completed(tio
->md
, rw
, false);
1290 if (rq
->cmd_flags
& REQ_FAILED
)
1293 dm_done(clone
, tio
->error
, mapped
);
1297 * Complete the clone and the original request with the error status
1298 * through softirq context.
1300 static void dm_complete_request(struct request
*rq
, int error
)
1302 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
1305 blk_complete_request(rq
);
1309 * Complete the not-mapped clone and the original request with the error status
1310 * through softirq context.
1311 * Target's rq_end_io() function isn't called.
1312 * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
1314 static void dm_kill_unmapped_request(struct request
*rq
, int error
)
1316 rq
->cmd_flags
|= REQ_FAILED
;
1317 dm_complete_request(rq
, error
);
1321 * Called with the clone's queue lock held (for non-blk-mq)
1323 static void end_clone_request(struct request
*clone
, int error
)
1325 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1327 if (!clone
->q
->mq_ops
) {
1329 * For just cleaning up the information of the queue in which
1330 * the clone was dispatched.
1331 * The clone is *NOT* freed actually here because it is alloced
1332 * from dm own mempool (REQ_ALLOCED isn't set).
1334 __blk_put_request(clone
->q
, clone
);
1338 * Actual request completion is done in a softirq context which doesn't
1339 * hold the clone's queue lock. Otherwise, deadlock could occur because:
1340 * - another request may be submitted by the upper level driver
1341 * of the stacking during the completion
1342 * - the submission which requires queue lock may be done
1343 * against this clone's queue
1345 dm_complete_request(tio
->orig
, error
);
1349 * Return maximum size of I/O possible at the supplied sector up to the current
1352 static sector_t
max_io_len_target_boundary(sector_t sector
, struct dm_target
*ti
)
1354 sector_t target_offset
= dm_target_offset(ti
, sector
);
1356 return ti
->len
- target_offset
;
1359 static sector_t
max_io_len(sector_t sector
, struct dm_target
*ti
)
1361 sector_t len
= max_io_len_target_boundary(sector
, ti
);
1362 sector_t offset
, max_len
;
1365 * Does the target need to split even further?
1367 if (ti
->max_io_len
) {
1368 offset
= dm_target_offset(ti
, sector
);
1369 if (unlikely(ti
->max_io_len
& (ti
->max_io_len
- 1)))
1370 max_len
= sector_div(offset
, ti
->max_io_len
);
1372 max_len
= offset
& (ti
->max_io_len
- 1);
1373 max_len
= ti
->max_io_len
- max_len
;
1382 int dm_set_target_max_io_len(struct dm_target
*ti
, sector_t len
)
1384 if (len
> UINT_MAX
) {
1385 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
1386 (unsigned long long)len
, UINT_MAX
);
1387 ti
->error
= "Maximum size of target IO is too large";
1391 ti
->max_io_len
= (uint32_t) len
;
1395 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len
);
1398 * A target may call dm_accept_partial_bio only from the map routine. It is
1399 * allowed for all bio types except REQ_FLUSH.
1401 * dm_accept_partial_bio informs the dm that the target only wants to process
1402 * additional n_sectors sectors of the bio and the rest of the data should be
1403 * sent in a next bio.
1405 * A diagram that explains the arithmetics:
1406 * +--------------------+---------------+-------+
1408 * +--------------------+---------------+-------+
1410 * <-------------- *tio->len_ptr --------------->
1411 * <------- bi_size ------->
1414 * Region 1 was already iterated over with bio_advance or similar function.
1415 * (it may be empty if the target doesn't use bio_advance)
1416 * Region 2 is the remaining bio size that the target wants to process.
1417 * (it may be empty if region 1 is non-empty, although there is no reason
1419 * The target requires that region 3 is to be sent in the next bio.
1421 * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
1422 * the partially processed part (the sum of regions 1+2) must be the same for all
1423 * copies of the bio.
1425 void dm_accept_partial_bio(struct bio
*bio
, unsigned n_sectors
)
1427 struct dm_target_io
*tio
= container_of(bio
, struct dm_target_io
, clone
);
1428 unsigned bi_size
= bio
->bi_iter
.bi_size
>> SECTOR_SHIFT
;
1429 BUG_ON(bio
->bi_rw
& REQ_FLUSH
);
1430 BUG_ON(bi_size
> *tio
->len_ptr
);
1431 BUG_ON(n_sectors
> bi_size
);
1432 *tio
->len_ptr
-= bi_size
- n_sectors
;
1433 bio
->bi_iter
.bi_size
= n_sectors
<< SECTOR_SHIFT
;
1435 EXPORT_SYMBOL_GPL(dm_accept_partial_bio
);
1437 static void __map_bio(struct dm_target_io
*tio
)
1441 struct mapped_device
*md
;
1442 struct bio
*clone
= &tio
->clone
;
1443 struct dm_target
*ti
= tio
->ti
;
1445 clone
->bi_end_io
= clone_endio
;
1448 * Map the clone. If r == 0 we don't need to do
1449 * anything, the target has assumed ownership of
1452 atomic_inc(&tio
->io
->io_count
);
1453 sector
= clone
->bi_iter
.bi_sector
;
1454 r
= ti
->type
->map(ti
, clone
);
1455 if (r
== DM_MAPIO_REMAPPED
) {
1456 /* the bio has been remapped so dispatch it */
1458 trace_block_bio_remap(bdev_get_queue(clone
->bi_bdev
), clone
,
1459 tio
->io
->bio
->bi_bdev
->bd_dev
, sector
);
1461 generic_make_request(clone
);
1462 } else if (r
< 0 || r
== DM_MAPIO_REQUEUE
) {
1463 /* error the io and bail out, or requeue it if needed */
1465 dec_pending(tio
->io
, r
);
1467 } else if (r
!= DM_MAPIO_SUBMITTED
) {
1468 DMWARN("unimplemented target map return value: %d", r
);
1474 struct mapped_device
*md
;
1475 struct dm_table
*map
;
1479 unsigned sector_count
;
1482 static void bio_setup_sector(struct bio
*bio
, sector_t sector
, unsigned len
)
1484 bio
->bi_iter
.bi_sector
= sector
;
1485 bio
->bi_iter
.bi_size
= to_bytes(len
);
1489 * Creates a bio that consists of range of complete bvecs.
1491 static void clone_bio(struct dm_target_io
*tio
, struct bio
*bio
,
1492 sector_t sector
, unsigned len
)
1494 struct bio
*clone
= &tio
->clone
;
1496 __bio_clone_fast(clone
, bio
);
1498 if (bio_integrity(bio
))
1499 bio_integrity_clone(clone
, bio
, GFP_NOIO
);
1501 bio_advance(clone
, to_bytes(sector
- clone
->bi_iter
.bi_sector
));
1502 clone
->bi_iter
.bi_size
= to_bytes(len
);
1504 if (bio_integrity(bio
))
1505 bio_integrity_trim(clone
, 0, len
);
1508 static struct dm_target_io
*alloc_tio(struct clone_info
*ci
,
1509 struct dm_target
*ti
,
1510 unsigned target_bio_nr
)
1512 struct dm_target_io
*tio
;
1515 clone
= bio_alloc_bioset(GFP_NOIO
, 0, ci
->md
->bs
);
1516 tio
= container_of(clone
, struct dm_target_io
, clone
);
1520 tio
->target_bio_nr
= target_bio_nr
;
1525 static void __clone_and_map_simple_bio(struct clone_info
*ci
,
1526 struct dm_target
*ti
,
1527 unsigned target_bio_nr
, unsigned *len
)
1529 struct dm_target_io
*tio
= alloc_tio(ci
, ti
, target_bio_nr
);
1530 struct bio
*clone
= &tio
->clone
;
1534 __bio_clone_fast(clone
, ci
->bio
);
1536 bio_setup_sector(clone
, ci
->sector
, *len
);
1541 static void __send_duplicate_bios(struct clone_info
*ci
, struct dm_target
*ti
,
1542 unsigned num_bios
, unsigned *len
)
1544 unsigned target_bio_nr
;
1546 for (target_bio_nr
= 0; target_bio_nr
< num_bios
; target_bio_nr
++)
1547 __clone_and_map_simple_bio(ci
, ti
, target_bio_nr
, len
);
1550 static int __send_empty_flush(struct clone_info
*ci
)
1552 unsigned target_nr
= 0;
1553 struct dm_target
*ti
;
1555 BUG_ON(bio_has_data(ci
->bio
));
1556 while ((ti
= dm_table_get_target(ci
->map
, target_nr
++)))
1557 __send_duplicate_bios(ci
, ti
, ti
->num_flush_bios
, NULL
);
1562 static void __clone_and_map_data_bio(struct clone_info
*ci
, struct dm_target
*ti
,
1563 sector_t sector
, unsigned *len
)
1565 struct bio
*bio
= ci
->bio
;
1566 struct dm_target_io
*tio
;
1567 unsigned target_bio_nr
;
1568 unsigned num_target_bios
= 1;
1571 * Does the target want to receive duplicate copies of the bio?
1573 if (bio_data_dir(bio
) == WRITE
&& ti
->num_write_bios
)
1574 num_target_bios
= ti
->num_write_bios(ti
, bio
);
1576 for (target_bio_nr
= 0; target_bio_nr
< num_target_bios
; target_bio_nr
++) {
1577 tio
= alloc_tio(ci
, ti
, target_bio_nr
);
1579 clone_bio(tio
, bio
, sector
, *len
);
1584 typedef unsigned (*get_num_bios_fn
)(struct dm_target
*ti
);
1586 static unsigned get_num_discard_bios(struct dm_target
*ti
)
1588 return ti
->num_discard_bios
;
1591 static unsigned get_num_write_same_bios(struct dm_target
*ti
)
1593 return ti
->num_write_same_bios
;
1596 typedef bool (*is_split_required_fn
)(struct dm_target
*ti
);
1598 static bool is_split_required_for_discard(struct dm_target
*ti
)
1600 return ti
->split_discard_bios
;
1603 static int __send_changing_extent_only(struct clone_info
*ci
,
1604 get_num_bios_fn get_num_bios
,
1605 is_split_required_fn is_split_required
)
1607 struct dm_target
*ti
;
1612 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1613 if (!dm_target_is_valid(ti
))
1617 * Even though the device advertised support for this type of
1618 * request, that does not mean every target supports it, and
1619 * reconfiguration might also have changed that since the
1620 * check was performed.
1622 num_bios
= get_num_bios
? get_num_bios(ti
) : 0;
1626 if (is_split_required
&& !is_split_required(ti
))
1627 len
= min((sector_t
)ci
->sector_count
, max_io_len_target_boundary(ci
->sector
, ti
));
1629 len
= min((sector_t
)ci
->sector_count
, max_io_len(ci
->sector
, ti
));
1631 __send_duplicate_bios(ci
, ti
, num_bios
, &len
);
1634 } while (ci
->sector_count
-= len
);
1639 static int __send_discard(struct clone_info
*ci
)
1641 return __send_changing_extent_only(ci
, get_num_discard_bios
,
1642 is_split_required_for_discard
);
1645 static int __send_write_same(struct clone_info
*ci
)
1647 return __send_changing_extent_only(ci
, get_num_write_same_bios
, NULL
);
1651 * Select the correct strategy for processing a non-flush bio.
1653 static int __split_and_process_non_flush(struct clone_info
*ci
)
1655 struct bio
*bio
= ci
->bio
;
1656 struct dm_target
*ti
;
1659 if (unlikely(bio
->bi_rw
& REQ_DISCARD
))
1660 return __send_discard(ci
);
1661 else if (unlikely(bio
->bi_rw
& REQ_WRITE_SAME
))
1662 return __send_write_same(ci
);
1664 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1665 if (!dm_target_is_valid(ti
))
1668 len
= min_t(sector_t
, max_io_len(ci
->sector
, ti
), ci
->sector_count
);
1670 __clone_and_map_data_bio(ci
, ti
, ci
->sector
, &len
);
1673 ci
->sector_count
-= len
;
1679 * Entry point to split a bio into clones and submit them to the targets.
1681 static void __split_and_process_bio(struct mapped_device
*md
,
1682 struct dm_table
*map
, struct bio
*bio
)
1684 struct clone_info ci
;
1687 if (unlikely(!map
)) {
1694 ci
.io
= alloc_io(md
);
1696 atomic_set(&ci
.io
->io_count
, 1);
1699 spin_lock_init(&ci
.io
->endio_lock
);
1700 ci
.sector
= bio
->bi_iter
.bi_sector
;
1702 start_io_acct(ci
.io
);
1704 if (bio
->bi_rw
& REQ_FLUSH
) {
1705 ci
.bio
= &ci
.md
->flush_bio
;
1706 ci
.sector_count
= 0;
1707 error
= __send_empty_flush(&ci
);
1708 /* dec_pending submits any data associated with flush */
1711 ci
.sector_count
= bio_sectors(bio
);
1712 while (ci
.sector_count
&& !error
)
1713 error
= __split_and_process_non_flush(&ci
);
1716 /* drop the extra reference count */
1717 dec_pending(ci
.io
, error
);
1719 /*-----------------------------------------------------------------
1721 *---------------------------------------------------------------*/
1724 * The request function that just remaps the bio built up by
1727 static void dm_make_request(struct request_queue
*q
, struct bio
*bio
)
1729 int rw
= bio_data_dir(bio
);
1730 struct mapped_device
*md
= q
->queuedata
;
1732 struct dm_table
*map
;
1734 map
= dm_get_live_table(md
, &srcu_idx
);
1736 blk_queue_split(q
, &bio
, q
->bio_split
);
1738 generic_start_io_acct(rw
, bio_sectors(bio
), &dm_disk(md
)->part0
);
1740 /* if we're suspended, we have to queue this io for later */
1741 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
))) {
1742 dm_put_live_table(md
, srcu_idx
);
1744 if (bio_rw(bio
) != READA
)
1751 __split_and_process_bio(md
, map
, bio
);
1752 dm_put_live_table(md
, srcu_idx
);
1756 int dm_request_based(struct mapped_device
*md
)
1758 return blk_queue_stackable(md
->queue
);
1761 static void dm_dispatch_clone_request(struct request
*clone
, struct request
*rq
)
1765 if (blk_queue_io_stat(clone
->q
))
1766 clone
->cmd_flags
|= REQ_IO_STAT
;
1768 clone
->start_time
= jiffies
;
1769 r
= blk_insert_cloned_request(clone
->q
, clone
);
1771 /* must complete clone in terms of original request */
1772 dm_complete_request(rq
, r
);
1775 static int dm_rq_bio_constructor(struct bio
*bio
, struct bio
*bio_orig
,
1778 struct dm_rq_target_io
*tio
= data
;
1779 struct dm_rq_clone_bio_info
*info
=
1780 container_of(bio
, struct dm_rq_clone_bio_info
, clone
);
1782 info
->orig
= bio_orig
;
1784 bio
->bi_end_io
= end_clone_bio
;
1789 static int setup_clone(struct request
*clone
, struct request
*rq
,
1790 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
1794 r
= blk_rq_prep_clone(clone
, rq
, tio
->md
->bs
, gfp_mask
,
1795 dm_rq_bio_constructor
, tio
);
1799 clone
->cmd
= rq
->cmd
;
1800 clone
->cmd_len
= rq
->cmd_len
;
1801 clone
->sense
= rq
->sense
;
1802 clone
->end_io
= end_clone_request
;
1803 clone
->end_io_data
= tio
;
1810 static struct request
*clone_rq(struct request
*rq
, struct mapped_device
*md
,
1811 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
1814 * Do not allocate a clone if tio->clone was already set
1815 * (see: dm_mq_queue_rq).
1817 bool alloc_clone
= !tio
->clone
;
1818 struct request
*clone
;
1821 clone
= alloc_clone_request(md
, gfp_mask
);
1827 blk_rq_init(NULL
, clone
);
1828 if (setup_clone(clone
, rq
, tio
, gfp_mask
)) {
1831 free_clone_request(md
, clone
);
1838 static void map_tio_request(struct kthread_work
*work
);
1840 static void init_tio(struct dm_rq_target_io
*tio
, struct request
*rq
,
1841 struct mapped_device
*md
)
1848 memset(&tio
->info
, 0, sizeof(tio
->info
));
1849 if (md
->kworker_task
)
1850 init_kthread_work(&tio
->work
, map_tio_request
);
1853 static struct dm_rq_target_io
*prep_tio(struct request
*rq
,
1854 struct mapped_device
*md
, gfp_t gfp_mask
)
1856 struct dm_rq_target_io
*tio
;
1858 struct dm_table
*table
;
1860 tio
= alloc_rq_tio(md
, gfp_mask
);
1864 init_tio(tio
, rq
, md
);
1866 table
= dm_get_live_table(md
, &srcu_idx
);
1867 if (!dm_table_mq_request_based(table
)) {
1868 if (!clone_rq(rq
, md
, tio
, gfp_mask
)) {
1869 dm_put_live_table(md
, srcu_idx
);
1874 dm_put_live_table(md
, srcu_idx
);
1880 * Called with the queue lock held.
1882 static int dm_prep_fn(struct request_queue
*q
, struct request
*rq
)
1884 struct mapped_device
*md
= q
->queuedata
;
1885 struct dm_rq_target_io
*tio
;
1887 if (unlikely(rq
->special
)) {
1888 DMWARN("Already has something in rq->special.");
1889 return BLKPREP_KILL
;
1892 tio
= prep_tio(rq
, md
, GFP_ATOMIC
);
1894 return BLKPREP_DEFER
;
1897 rq
->cmd_flags
|= REQ_DONTPREP
;
1904 * 0 : the request has been processed
1905 * DM_MAPIO_REQUEUE : the original request needs to be requeued
1906 * < 0 : the request was completed due to failure
1908 static int map_request(struct dm_rq_target_io
*tio
, struct request
*rq
,
1909 struct mapped_device
*md
)
1912 struct dm_target
*ti
= tio
->ti
;
1913 struct request
*clone
= NULL
;
1917 r
= ti
->type
->map_rq(ti
, clone
, &tio
->info
);
1919 r
= ti
->type
->clone_and_map_rq(ti
, rq
, &tio
->info
, &clone
);
1921 /* The target wants to complete the I/O */
1922 dm_kill_unmapped_request(rq
, r
);
1925 if (r
!= DM_MAPIO_REMAPPED
)
1927 if (setup_clone(clone
, rq
, tio
, GFP_ATOMIC
)) {
1929 ti
->type
->release_clone_rq(clone
);
1930 return DM_MAPIO_REQUEUE
;
1935 case DM_MAPIO_SUBMITTED
:
1936 /* The target has taken the I/O to submit by itself later */
1938 case DM_MAPIO_REMAPPED
:
1939 /* The target has remapped the I/O so dispatch it */
1940 trace_block_rq_remap(clone
->q
, clone
, disk_devt(dm_disk(md
)),
1942 dm_dispatch_clone_request(clone
, rq
);
1944 case DM_MAPIO_REQUEUE
:
1945 /* The target wants to requeue the I/O */
1946 dm_requeue_original_request(md
, tio
->orig
);
1950 DMWARN("unimplemented target map return value: %d", r
);
1954 /* The target wants to complete the I/O */
1955 dm_kill_unmapped_request(rq
, r
);
1962 static void map_tio_request(struct kthread_work
*work
)
1964 struct dm_rq_target_io
*tio
= container_of(work
, struct dm_rq_target_io
, work
);
1965 struct request
*rq
= tio
->orig
;
1966 struct mapped_device
*md
= tio
->md
;
1968 if (map_request(tio
, rq
, md
) == DM_MAPIO_REQUEUE
)
1969 dm_requeue_original_request(md
, rq
);
1972 static void dm_start_request(struct mapped_device
*md
, struct request
*orig
)
1974 if (!orig
->q
->mq_ops
)
1975 blk_start_request(orig
);
1977 blk_mq_start_request(orig
);
1978 atomic_inc(&md
->pending
[rq_data_dir(orig
)]);
1980 if (md
->seq_rq_merge_deadline_usecs
) {
1981 md
->last_rq_pos
= rq_end_sector(orig
);
1982 md
->last_rq_rw
= rq_data_dir(orig
);
1983 md
->last_rq_start_time
= ktime_get();
1986 if (unlikely(dm_stats_used(&md
->stats
))) {
1987 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
1988 tio
->duration_jiffies
= jiffies
;
1989 tio
->n_sectors
= blk_rq_sectors(orig
);
1990 dm_stats_account_io(&md
->stats
, orig
->cmd_flags
, blk_rq_pos(orig
),
1991 tio
->n_sectors
, false, 0, &tio
->stats_aux
);
1995 * Hold the md reference here for the in-flight I/O.
1996 * We can't rely on the reference count by device opener,
1997 * because the device may be closed during the request completion
1998 * when all bios are completed.
1999 * See the comment in rq_completed() too.
2004 #define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
2006 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device
*md
, char *buf
)
2008 return sprintf(buf
, "%u\n", md
->seq_rq_merge_deadline_usecs
);
2011 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device
*md
,
2012 const char *buf
, size_t count
)
2016 if (!dm_request_based(md
) || md
->use_blk_mq
)
2019 if (kstrtouint(buf
, 10, &deadline
))
2022 if (deadline
> MAX_SEQ_RQ_MERGE_DEADLINE_USECS
)
2023 deadline
= MAX_SEQ_RQ_MERGE_DEADLINE_USECS
;
2025 md
->seq_rq_merge_deadline_usecs
= deadline
;
2030 static bool dm_request_peeked_before_merge_deadline(struct mapped_device
*md
)
2032 ktime_t kt_deadline
;
2034 if (!md
->seq_rq_merge_deadline_usecs
)
2037 kt_deadline
= ns_to_ktime((u64
)md
->seq_rq_merge_deadline_usecs
* NSEC_PER_USEC
);
2038 kt_deadline
= ktime_add_safe(md
->last_rq_start_time
, kt_deadline
);
2040 return !ktime_after(ktime_get(), kt_deadline
);
2044 * q->request_fn for request-based dm.
2045 * Called with the queue lock held.
2047 static void dm_request_fn(struct request_queue
*q
)
2049 struct mapped_device
*md
= q
->queuedata
;
2051 struct dm_table
*map
= dm_get_live_table(md
, &srcu_idx
);
2052 struct dm_target
*ti
;
2054 struct dm_rq_target_io
*tio
;
2058 * For suspend, check blk_queue_stopped() and increment
2059 * ->pending within a single queue_lock not to increment the
2060 * number of in-flight I/Os after the queue is stopped in
2063 while (!blk_queue_stopped(q
)) {
2064 rq
= blk_peek_request(q
);
2068 /* always use block 0 to find the target for flushes for now */
2070 if (!(rq
->cmd_flags
& REQ_FLUSH
))
2071 pos
= blk_rq_pos(rq
);
2073 ti
= dm_table_find_target(map
, pos
);
2074 if (!dm_target_is_valid(ti
)) {
2076 * Must perform setup, that rq_completed() requires,
2077 * before calling dm_kill_unmapped_request
2079 DMERR_LIMIT("request attempted access beyond the end of device");
2080 dm_start_request(md
, rq
);
2081 dm_kill_unmapped_request(rq
, -EIO
);
2085 if (dm_request_peeked_before_merge_deadline(md
) &&
2086 md_in_flight(md
) && rq
->bio
&& rq
->bio
->bi_vcnt
== 1 &&
2087 md
->last_rq_pos
== pos
&& md
->last_rq_rw
== rq_data_dir(rq
))
2090 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
2093 dm_start_request(md
, rq
);
2095 tio
= tio_from_request(rq
);
2096 /* Establish tio->ti before queuing work (map_tio_request) */
2098 queue_kthread_work(&md
->kworker
, &tio
->work
);
2099 BUG_ON(!irqs_disabled());
2105 blk_delay_queue(q
, HZ
/ 100);
2107 dm_put_live_table(md
, srcu_idx
);
2110 static int dm_any_congested(void *congested_data
, int bdi_bits
)
2113 struct mapped_device
*md
= congested_data
;
2114 struct dm_table
*map
;
2116 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2117 map
= dm_get_live_table_fast(md
);
2120 * Request-based dm cares about only own queue for
2121 * the query about congestion status of request_queue
2123 if (dm_request_based(md
))
2124 r
= md
->queue
->backing_dev_info
.wb
.state
&
2127 r
= dm_table_any_congested(map
, bdi_bits
);
2129 dm_put_live_table_fast(md
);
2135 /*-----------------------------------------------------------------
2136 * An IDR is used to keep track of allocated minor numbers.
2137 *---------------------------------------------------------------*/
2138 static void free_minor(int minor
)
2140 spin_lock(&_minor_lock
);
2141 idr_remove(&_minor_idr
, minor
);
2142 spin_unlock(&_minor_lock
);
2146 * See if the device with a specific minor # is free.
2148 static int specific_minor(int minor
)
2152 if (minor
>= (1 << MINORBITS
))
2155 idr_preload(GFP_KERNEL
);
2156 spin_lock(&_minor_lock
);
2158 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, minor
, minor
+ 1, GFP_NOWAIT
);
2160 spin_unlock(&_minor_lock
);
2163 return r
== -ENOSPC
? -EBUSY
: r
;
2167 static int next_free_minor(int *minor
)
2171 idr_preload(GFP_KERNEL
);
2172 spin_lock(&_minor_lock
);
2174 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, 0, 1 << MINORBITS
, GFP_NOWAIT
);
2176 spin_unlock(&_minor_lock
);
2184 static const struct block_device_operations dm_blk_dops
;
2186 static void dm_wq_work(struct work_struct
*work
);
2188 static void dm_init_md_queue(struct mapped_device
*md
)
2191 * Request-based dm devices cannot be stacked on top of bio-based dm
2192 * devices. The type of this dm device may not have been decided yet.
2193 * The type is decided at the first table loading time.
2194 * To prevent problematic device stacking, clear the queue flag
2195 * for request stacking support until then.
2197 * This queue is new, so no concurrency on the queue_flags.
2199 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE
, md
->queue
);
2202 static void dm_init_old_md_queue(struct mapped_device
*md
)
2204 md
->use_blk_mq
= false;
2205 dm_init_md_queue(md
);
2208 * Initialize aspects of queue that aren't relevant for blk-mq
2210 md
->queue
->queuedata
= md
;
2211 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
2212 md
->queue
->backing_dev_info
.congested_data
= md
;
2214 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
2217 static void cleanup_mapped_device(struct mapped_device
*md
)
2220 destroy_workqueue(md
->wq
);
2221 if (md
->kworker_task
)
2222 kthread_stop(md
->kworker_task
);
2224 mempool_destroy(md
->io_pool
);
2226 mempool_destroy(md
->rq_pool
);
2228 bioset_free(md
->bs
);
2230 cleanup_srcu_struct(&md
->io_barrier
);
2233 spin_lock(&_minor_lock
);
2234 md
->disk
->private_data
= NULL
;
2235 spin_unlock(&_minor_lock
);
2236 if (blk_get_integrity(md
->disk
))
2237 blk_integrity_unregister(md
->disk
);
2238 del_gendisk(md
->disk
);
2243 blk_cleanup_queue(md
->queue
);
2252 * Allocate and initialise a blank device with a given minor.
2254 static struct mapped_device
*alloc_dev(int minor
)
2257 struct mapped_device
*md
= kzalloc(sizeof(*md
), GFP_KERNEL
);
2261 DMWARN("unable to allocate device, out of memory.");
2265 if (!try_module_get(THIS_MODULE
))
2266 goto bad_module_get
;
2268 /* get a minor number for the dev */
2269 if (minor
== DM_ANY_MINOR
)
2270 r
= next_free_minor(&minor
);
2272 r
= specific_minor(minor
);
2276 r
= init_srcu_struct(&md
->io_barrier
);
2278 goto bad_io_barrier
;
2280 md
->use_blk_mq
= use_blk_mq
;
2281 md
->type
= DM_TYPE_NONE
;
2282 mutex_init(&md
->suspend_lock
);
2283 mutex_init(&md
->type_lock
);
2284 mutex_init(&md
->table_devices_lock
);
2285 spin_lock_init(&md
->deferred_lock
);
2286 atomic_set(&md
->holders
, 1);
2287 atomic_set(&md
->open_count
, 0);
2288 atomic_set(&md
->event_nr
, 0);
2289 atomic_set(&md
->uevent_seq
, 0);
2290 INIT_LIST_HEAD(&md
->uevent_list
);
2291 INIT_LIST_HEAD(&md
->table_devices
);
2292 spin_lock_init(&md
->uevent_lock
);
2294 md
->queue
= blk_alloc_queue(GFP_KERNEL
);
2298 dm_init_md_queue(md
);
2300 md
->disk
= alloc_disk(1);
2304 atomic_set(&md
->pending
[0], 0);
2305 atomic_set(&md
->pending
[1], 0);
2306 init_waitqueue_head(&md
->wait
);
2307 INIT_WORK(&md
->work
, dm_wq_work
);
2308 init_waitqueue_head(&md
->eventq
);
2309 init_completion(&md
->kobj_holder
.completion
);
2310 md
->kworker_task
= NULL
;
2312 md
->disk
->major
= _major
;
2313 md
->disk
->first_minor
= minor
;
2314 md
->disk
->fops
= &dm_blk_dops
;
2315 md
->disk
->queue
= md
->queue
;
2316 md
->disk
->private_data
= md
;
2317 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
2319 format_dev_t(md
->name
, MKDEV(_major
, minor
));
2321 md
->wq
= alloc_workqueue("kdmflush", WQ_MEM_RECLAIM
, 0);
2325 md
->bdev
= bdget_disk(md
->disk
, 0);
2329 bio_init(&md
->flush_bio
);
2330 md
->flush_bio
.bi_bdev
= md
->bdev
;
2331 md
->flush_bio
.bi_rw
= WRITE_FLUSH
;
2333 dm_stats_init(&md
->stats
);
2335 /* Populate the mapping, nobody knows we exist yet */
2336 spin_lock(&_minor_lock
);
2337 old_md
= idr_replace(&_minor_idr
, md
, minor
);
2338 spin_unlock(&_minor_lock
);
2340 BUG_ON(old_md
!= MINOR_ALLOCED
);
2345 cleanup_mapped_device(md
);
2349 module_put(THIS_MODULE
);
2355 static void unlock_fs(struct mapped_device
*md
);
2357 static void free_dev(struct mapped_device
*md
)
2359 int minor
= MINOR(disk_devt(md
->disk
));
2363 cleanup_mapped_device(md
);
2365 blk_mq_free_tag_set(&md
->tag_set
);
2367 free_table_devices(&md
->table_devices
);
2368 dm_stats_cleanup(&md
->stats
);
2371 module_put(THIS_MODULE
);
2375 static void __bind_mempools(struct mapped_device
*md
, struct dm_table
*t
)
2377 struct dm_md_mempools
*p
= dm_table_get_md_mempools(t
);
2380 /* The md already has necessary mempools. */
2381 if (dm_table_get_type(t
) == DM_TYPE_BIO_BASED
) {
2383 * Reload bioset because front_pad may have changed
2384 * because a different table was loaded.
2386 bioset_free(md
->bs
);
2391 * There's no need to reload with request-based dm
2392 * because the size of front_pad doesn't change.
2393 * Note for future: If you are to reload bioset,
2394 * prep-ed requests in the queue may refer
2395 * to bio from the old bioset, so you must walk
2396 * through the queue to unprep.
2401 BUG_ON(!p
|| md
->io_pool
|| md
->rq_pool
|| md
->bs
);
2403 md
->io_pool
= p
->io_pool
;
2405 md
->rq_pool
= p
->rq_pool
;
2411 /* mempool bind completed, no longer need any mempools in the table */
2412 dm_table_free_md_mempools(t
);
2416 * Bind a table to the device.
2418 static void event_callback(void *context
)
2420 unsigned long flags
;
2422 struct mapped_device
*md
= (struct mapped_device
*) context
;
2424 spin_lock_irqsave(&md
->uevent_lock
, flags
);
2425 list_splice_init(&md
->uevent_list
, &uevents
);
2426 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
2428 dm_send_uevents(&uevents
, &disk_to_dev(md
->disk
)->kobj
);
2430 atomic_inc(&md
->event_nr
);
2431 wake_up(&md
->eventq
);
2435 * Protected by md->suspend_lock obtained by dm_swap_table().
2437 static void __set_size(struct mapped_device
*md
, sector_t size
)
2439 set_capacity(md
->disk
, size
);
2441 i_size_write(md
->bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
2445 * Returns old map, which caller must destroy.
2447 static struct dm_table
*__bind(struct mapped_device
*md
, struct dm_table
*t
,
2448 struct queue_limits
*limits
)
2450 struct dm_table
*old_map
;
2451 struct request_queue
*q
= md
->queue
;
2454 size
= dm_table_get_size(t
);
2457 * Wipe any geometry if the size of the table changed.
2459 if (size
!= dm_get_size(md
))
2460 memset(&md
->geometry
, 0, sizeof(md
->geometry
));
2462 __set_size(md
, size
);
2464 dm_table_event_callback(t
, event_callback
, md
);
2467 * The queue hasn't been stopped yet, if the old table type wasn't
2468 * for request-based during suspension. So stop it to prevent
2469 * I/O mapping before resume.
2470 * This must be done before setting the queue restrictions,
2471 * because request-based dm may be run just after the setting.
2473 if (dm_table_request_based(t
))
2476 __bind_mempools(md
, t
);
2478 old_map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
2479 rcu_assign_pointer(md
->map
, t
);
2480 md
->immutable_target_type
= dm_table_get_immutable_target_type(t
);
2482 dm_table_set_restrictions(t
, q
, limits
);
2490 * Returns unbound table for the caller to free.
2492 static struct dm_table
*__unbind(struct mapped_device
*md
)
2494 struct dm_table
*map
= rcu_dereference_protected(md
->map
, 1);
2499 dm_table_event_callback(map
, NULL
, NULL
);
2500 RCU_INIT_POINTER(md
->map
, NULL
);
2507 * Constructor for a new device.
2509 int dm_create(int minor
, struct mapped_device
**result
)
2511 struct mapped_device
*md
;
2513 md
= alloc_dev(minor
);
2524 * Functions to manage md->type.
2525 * All are required to hold md->type_lock.
2527 void dm_lock_md_type(struct mapped_device
*md
)
2529 mutex_lock(&md
->type_lock
);
2532 void dm_unlock_md_type(struct mapped_device
*md
)
2534 mutex_unlock(&md
->type_lock
);
2537 void dm_set_md_type(struct mapped_device
*md
, unsigned type
)
2539 BUG_ON(!mutex_is_locked(&md
->type_lock
));
2543 unsigned dm_get_md_type(struct mapped_device
*md
)
2545 BUG_ON(!mutex_is_locked(&md
->type_lock
));
2549 struct target_type
*dm_get_immutable_target_type(struct mapped_device
*md
)
2551 return md
->immutable_target_type
;
2555 * The queue_limits are only valid as long as you have a reference
2558 struct queue_limits
*dm_get_queue_limits(struct mapped_device
*md
)
2560 BUG_ON(!atomic_read(&md
->holders
));
2561 return &md
->queue
->limits
;
2563 EXPORT_SYMBOL_GPL(dm_get_queue_limits
);
2565 static void init_rq_based_worker_thread(struct mapped_device
*md
)
2567 /* Initialize the request-based DM worker thread */
2568 init_kthread_worker(&md
->kworker
);
2569 md
->kworker_task
= kthread_run(kthread_worker_fn
, &md
->kworker
,
2570 "kdmwork-%s", dm_device_name(md
));
2574 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2576 static int dm_init_request_based_queue(struct mapped_device
*md
)
2578 struct request_queue
*q
= NULL
;
2580 /* Fully initialize the queue */
2581 q
= blk_init_allocated_queue(md
->queue
, dm_request_fn
, NULL
);
2585 /* disable dm_request_fn's merge heuristic by default */
2586 md
->seq_rq_merge_deadline_usecs
= 0;
2589 dm_init_old_md_queue(md
);
2590 blk_queue_softirq_done(md
->queue
, dm_softirq_done
);
2591 blk_queue_prep_rq(md
->queue
, dm_prep_fn
);
2593 init_rq_based_worker_thread(md
);
2595 elv_register_queue(md
->queue
);
2600 static int dm_mq_init_request(void *data
, struct request
*rq
,
2601 unsigned int hctx_idx
, unsigned int request_idx
,
2602 unsigned int numa_node
)
2604 struct mapped_device
*md
= data
;
2605 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
2608 * Must initialize md member of tio, otherwise it won't
2609 * be available in dm_mq_queue_rq.
2616 static int dm_mq_queue_rq(struct blk_mq_hw_ctx
*hctx
,
2617 const struct blk_mq_queue_data
*bd
)
2619 struct request
*rq
= bd
->rq
;
2620 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
2621 struct mapped_device
*md
= tio
->md
;
2623 struct dm_table
*map
= dm_get_live_table(md
, &srcu_idx
);
2624 struct dm_target
*ti
;
2627 /* always use block 0 to find the target for flushes for now */
2629 if (!(rq
->cmd_flags
& REQ_FLUSH
))
2630 pos
= blk_rq_pos(rq
);
2632 ti
= dm_table_find_target(map
, pos
);
2633 if (!dm_target_is_valid(ti
)) {
2634 dm_put_live_table(md
, srcu_idx
);
2635 DMERR_LIMIT("request attempted access beyond the end of device");
2637 * Must perform setup, that rq_completed() requires,
2638 * before returning BLK_MQ_RQ_QUEUE_ERROR
2640 dm_start_request(md
, rq
);
2641 return BLK_MQ_RQ_QUEUE_ERROR
;
2643 dm_put_live_table(md
, srcu_idx
);
2645 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
2646 return BLK_MQ_RQ_QUEUE_BUSY
;
2648 dm_start_request(md
, rq
);
2650 /* Init tio using md established in .init_request */
2651 init_tio(tio
, rq
, md
);
2654 * Establish tio->ti before queuing work (map_tio_request)
2655 * or making direct call to map_request().
2659 /* Clone the request if underlying devices aren't blk-mq */
2660 if (dm_table_get_type(map
) == DM_TYPE_REQUEST_BASED
) {
2661 /* clone request is allocated at the end of the pdu */
2662 tio
->clone
= (void *)blk_mq_rq_to_pdu(rq
) + sizeof(struct dm_rq_target_io
);
2663 (void) clone_rq(rq
, md
, tio
, GFP_ATOMIC
);
2664 queue_kthread_work(&md
->kworker
, &tio
->work
);
2666 /* Direct call is fine since .queue_rq allows allocations */
2667 if (map_request(tio
, rq
, md
) == DM_MAPIO_REQUEUE
) {
2668 /* Undo dm_start_request() before requeuing */
2669 rq_end_stats(md
, rq
);
2670 rq_completed(md
, rq_data_dir(rq
), false);
2671 return BLK_MQ_RQ_QUEUE_BUSY
;
2675 return BLK_MQ_RQ_QUEUE_OK
;
2678 static struct blk_mq_ops dm_mq_ops
= {
2679 .queue_rq
= dm_mq_queue_rq
,
2680 .map_queue
= blk_mq_map_queue
,
2681 .complete
= dm_softirq_done
,
2682 .init_request
= dm_mq_init_request
,
2685 static int dm_init_request_based_blk_mq_queue(struct mapped_device
*md
)
2687 unsigned md_type
= dm_get_md_type(md
);
2688 struct request_queue
*q
;
2691 memset(&md
->tag_set
, 0, sizeof(md
->tag_set
));
2692 md
->tag_set
.ops
= &dm_mq_ops
;
2693 md
->tag_set
.queue_depth
= BLKDEV_MAX_RQ
;
2694 md
->tag_set
.numa_node
= NUMA_NO_NODE
;
2695 md
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2696 md
->tag_set
.nr_hw_queues
= 1;
2697 if (md_type
== DM_TYPE_REQUEST_BASED
) {
2698 /* make the memory for non-blk-mq clone part of the pdu */
2699 md
->tag_set
.cmd_size
= sizeof(struct dm_rq_target_io
) + sizeof(struct request
);
2701 md
->tag_set
.cmd_size
= sizeof(struct dm_rq_target_io
);
2702 md
->tag_set
.driver_data
= md
;
2704 err
= blk_mq_alloc_tag_set(&md
->tag_set
);
2708 q
= blk_mq_init_allocated_queue(&md
->tag_set
, md
->queue
);
2714 dm_init_md_queue(md
);
2716 /* backfill 'mq' sysfs registration normally done in blk_register_queue */
2717 blk_mq_register_disk(md
->disk
);
2719 if (md_type
== DM_TYPE_REQUEST_BASED
)
2720 init_rq_based_worker_thread(md
);
2725 blk_mq_free_tag_set(&md
->tag_set
);
2729 static unsigned filter_md_type(unsigned type
, struct mapped_device
*md
)
2731 if (type
== DM_TYPE_BIO_BASED
)
2734 return !md
->use_blk_mq
? DM_TYPE_REQUEST_BASED
: DM_TYPE_MQ_REQUEST_BASED
;
2738 * Setup the DM device's queue based on md's type
2740 int dm_setup_md_queue(struct mapped_device
*md
)
2743 unsigned md_type
= filter_md_type(dm_get_md_type(md
), md
);
2746 case DM_TYPE_REQUEST_BASED
:
2747 r
= dm_init_request_based_queue(md
);
2749 DMWARN("Cannot initialize queue for request-based mapped device");
2753 case DM_TYPE_MQ_REQUEST_BASED
:
2754 r
= dm_init_request_based_blk_mq_queue(md
);
2756 DMWARN("Cannot initialize queue for request-based blk-mq mapped device");
2760 case DM_TYPE_BIO_BASED
:
2761 dm_init_old_md_queue(md
);
2762 blk_queue_make_request(md
->queue
, dm_make_request
);
2769 struct mapped_device
*dm_get_md(dev_t dev
)
2771 struct mapped_device
*md
;
2772 unsigned minor
= MINOR(dev
);
2774 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
2777 spin_lock(&_minor_lock
);
2779 md
= idr_find(&_minor_idr
, minor
);
2781 if ((md
== MINOR_ALLOCED
||
2782 (MINOR(disk_devt(dm_disk(md
))) != minor
) ||
2783 dm_deleting_md(md
) ||
2784 test_bit(DMF_FREEING
, &md
->flags
))) {
2792 spin_unlock(&_minor_lock
);
2796 EXPORT_SYMBOL_GPL(dm_get_md
);
2798 void *dm_get_mdptr(struct mapped_device
*md
)
2800 return md
->interface_ptr
;
2803 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
2805 md
->interface_ptr
= ptr
;
2808 void dm_get(struct mapped_device
*md
)
2810 atomic_inc(&md
->holders
);
2811 BUG_ON(test_bit(DMF_FREEING
, &md
->flags
));
2814 int dm_hold(struct mapped_device
*md
)
2816 spin_lock(&_minor_lock
);
2817 if (test_bit(DMF_FREEING
, &md
->flags
)) {
2818 spin_unlock(&_minor_lock
);
2822 spin_unlock(&_minor_lock
);
2825 EXPORT_SYMBOL_GPL(dm_hold
);
2827 const char *dm_device_name(struct mapped_device
*md
)
2831 EXPORT_SYMBOL_GPL(dm_device_name
);
2833 static void __dm_destroy(struct mapped_device
*md
, bool wait
)
2835 struct dm_table
*map
;
2840 map
= dm_get_live_table(md
, &srcu_idx
);
2842 spin_lock(&_minor_lock
);
2843 idr_replace(&_minor_idr
, MINOR_ALLOCED
, MINOR(disk_devt(dm_disk(md
))));
2844 set_bit(DMF_FREEING
, &md
->flags
);
2845 spin_unlock(&_minor_lock
);
2847 if (dm_request_based(md
) && md
->kworker_task
)
2848 flush_kthread_worker(&md
->kworker
);
2851 * Take suspend_lock so that presuspend and postsuspend methods
2852 * do not race with internal suspend.
2854 mutex_lock(&md
->suspend_lock
);
2855 if (!dm_suspended_md(md
)) {
2856 dm_table_presuspend_targets(map
);
2857 dm_table_postsuspend_targets(map
);
2859 mutex_unlock(&md
->suspend_lock
);
2861 /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
2862 dm_put_live_table(md
, srcu_idx
);
2865 * Rare, but there may be I/O requests still going to complete,
2866 * for example. Wait for all references to disappear.
2867 * No one should increment the reference count of the mapped_device,
2868 * after the mapped_device state becomes DMF_FREEING.
2871 while (atomic_read(&md
->holders
))
2873 else if (atomic_read(&md
->holders
))
2874 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2875 dm_device_name(md
), atomic_read(&md
->holders
));
2878 dm_table_destroy(__unbind(md
));
2882 void dm_destroy(struct mapped_device
*md
)
2884 __dm_destroy(md
, true);
2887 void dm_destroy_immediate(struct mapped_device
*md
)
2889 __dm_destroy(md
, false);
2892 void dm_put(struct mapped_device
*md
)
2894 atomic_dec(&md
->holders
);
2896 EXPORT_SYMBOL_GPL(dm_put
);
2898 static int dm_wait_for_completion(struct mapped_device
*md
, int interruptible
)
2901 DECLARE_WAITQUEUE(wait
, current
);
2903 add_wait_queue(&md
->wait
, &wait
);
2906 set_current_state(interruptible
);
2908 if (!md_in_flight(md
))
2911 if (interruptible
== TASK_INTERRUPTIBLE
&&
2912 signal_pending(current
)) {
2919 set_current_state(TASK_RUNNING
);
2921 remove_wait_queue(&md
->wait
, &wait
);
2927 * Process the deferred bios
2929 static void dm_wq_work(struct work_struct
*work
)
2931 struct mapped_device
*md
= container_of(work
, struct mapped_device
,
2935 struct dm_table
*map
;
2937 map
= dm_get_live_table(md
, &srcu_idx
);
2939 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2940 spin_lock_irq(&md
->deferred_lock
);
2941 c
= bio_list_pop(&md
->deferred
);
2942 spin_unlock_irq(&md
->deferred_lock
);
2947 if (dm_request_based(md
))
2948 generic_make_request(c
);
2950 __split_and_process_bio(md
, map
, c
);
2953 dm_put_live_table(md
, srcu_idx
);
2956 static void dm_queue_flush(struct mapped_device
*md
)
2958 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2959 smp_mb__after_atomic();
2960 queue_work(md
->wq
, &md
->work
);
2964 * Swap in a new table, returning the old one for the caller to destroy.
2966 struct dm_table
*dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
2968 struct dm_table
*live_map
= NULL
, *map
= ERR_PTR(-EINVAL
);
2969 struct queue_limits limits
;
2972 mutex_lock(&md
->suspend_lock
);
2974 /* device must be suspended */
2975 if (!dm_suspended_md(md
))
2979 * If the new table has no data devices, retain the existing limits.
2980 * This helps multipath with queue_if_no_path if all paths disappear,
2981 * then new I/O is queued based on these limits, and then some paths
2984 if (dm_table_has_no_data_devices(table
)) {
2985 live_map
= dm_get_live_table_fast(md
);
2987 limits
= md
->queue
->limits
;
2988 dm_put_live_table_fast(md
);
2992 r
= dm_calculate_queue_limits(table
, &limits
);
2999 map
= __bind(md
, table
, &limits
);
3002 mutex_unlock(&md
->suspend_lock
);
3007 * Functions to lock and unlock any filesystem running on the
3010 static int lock_fs(struct mapped_device
*md
)
3014 WARN_ON(md
->frozen_sb
);
3016 md
->frozen_sb
= freeze_bdev(md
->bdev
);
3017 if (IS_ERR(md
->frozen_sb
)) {
3018 r
= PTR_ERR(md
->frozen_sb
);
3019 md
->frozen_sb
= NULL
;
3023 set_bit(DMF_FROZEN
, &md
->flags
);
3028 static void unlock_fs(struct mapped_device
*md
)
3030 if (!test_bit(DMF_FROZEN
, &md
->flags
))
3033 thaw_bdev(md
->bdev
, md
->frozen_sb
);
3034 md
->frozen_sb
= NULL
;
3035 clear_bit(DMF_FROZEN
, &md
->flags
);
3039 * If __dm_suspend returns 0, the device is completely quiescent
3040 * now. There is no request-processing activity. All new requests
3041 * are being added to md->deferred list.
3043 * Caller must hold md->suspend_lock
3045 static int __dm_suspend(struct mapped_device
*md
, struct dm_table
*map
,
3046 unsigned suspend_flags
, int interruptible
)
3048 bool do_lockfs
= suspend_flags
& DM_SUSPEND_LOCKFS_FLAG
;
3049 bool noflush
= suspend_flags
& DM_SUSPEND_NOFLUSH_FLAG
;
3053 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
3054 * This flag is cleared before dm_suspend returns.
3057 set_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
3060 * This gets reverted if there's an error later and the targets
3061 * provide the .presuspend_undo hook.
3063 dm_table_presuspend_targets(map
);
3066 * Flush I/O to the device.
3067 * Any I/O submitted after lock_fs() may not be flushed.
3068 * noflush takes precedence over do_lockfs.
3069 * (lock_fs() flushes I/Os and waits for them to complete.)
3071 if (!noflush
&& do_lockfs
) {
3074 dm_table_presuspend_undo_targets(map
);
3080 * Here we must make sure that no processes are submitting requests
3081 * to target drivers i.e. no one may be executing
3082 * __split_and_process_bio. This is called from dm_request and
3085 * To get all processes out of __split_and_process_bio in dm_request,
3086 * we take the write lock. To prevent any process from reentering
3087 * __split_and_process_bio from dm_request and quiesce the thread
3088 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
3089 * flush_workqueue(md->wq).
3091 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
3093 synchronize_srcu(&md
->io_barrier
);
3096 * Stop md->queue before flushing md->wq in case request-based
3097 * dm defers requests to md->wq from md->queue.
3099 if (dm_request_based(md
)) {
3100 stop_queue(md
->queue
);
3101 if (md
->kworker_task
)
3102 flush_kthread_worker(&md
->kworker
);
3105 flush_workqueue(md
->wq
);
3108 * At this point no more requests are entering target request routines.
3109 * We call dm_wait_for_completion to wait for all existing requests
3112 r
= dm_wait_for_completion(md
, interruptible
);
3115 clear_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
3117 synchronize_srcu(&md
->io_barrier
);
3119 /* were we interrupted ? */
3123 if (dm_request_based(md
))
3124 start_queue(md
->queue
);
3127 dm_table_presuspend_undo_targets(map
);
3128 /* pushback list is already flushed, so skip flush */
3135 * We need to be able to change a mapping table under a mounted
3136 * filesystem. For example we might want to move some data in
3137 * the background. Before the table can be swapped with
3138 * dm_bind_table, dm_suspend must be called to flush any in
3139 * flight bios and ensure that any further io gets deferred.
3142 * Suspend mechanism in request-based dm.
3144 * 1. Flush all I/Os by lock_fs() if needed.
3145 * 2. Stop dispatching any I/O by stopping the request_queue.
3146 * 3. Wait for all in-flight I/Os to be completed or requeued.
3148 * To abort suspend, start the request_queue.
3150 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
3152 struct dm_table
*map
= NULL
;
3156 mutex_lock_nested(&md
->suspend_lock
, SINGLE_DEPTH_NESTING
);
3158 if (dm_suspended_md(md
)) {
3163 if (dm_suspended_internally_md(md
)) {
3164 /* already internally suspended, wait for internal resume */
3165 mutex_unlock(&md
->suspend_lock
);
3166 r
= wait_on_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
, TASK_INTERRUPTIBLE
);
3172 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3174 r
= __dm_suspend(md
, map
, suspend_flags
, TASK_INTERRUPTIBLE
);
3178 set_bit(DMF_SUSPENDED
, &md
->flags
);
3180 dm_table_postsuspend_targets(map
);
3183 mutex_unlock(&md
->suspend_lock
);
3187 static int __dm_resume(struct mapped_device
*md
, struct dm_table
*map
)
3190 int r
= dm_table_resume_targets(map
);
3198 * Flushing deferred I/Os must be done after targets are resumed
3199 * so that mapping of targets can work correctly.
3200 * Request-based dm is queueing the deferred I/Os in its request_queue.
3202 if (dm_request_based(md
))
3203 start_queue(md
->queue
);
3210 int dm_resume(struct mapped_device
*md
)
3213 struct dm_table
*map
= NULL
;
3216 mutex_lock_nested(&md
->suspend_lock
, SINGLE_DEPTH_NESTING
);
3218 if (!dm_suspended_md(md
))
3221 if (dm_suspended_internally_md(md
)) {
3222 /* already internally suspended, wait for internal resume */
3223 mutex_unlock(&md
->suspend_lock
);
3224 r
= wait_on_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
, TASK_INTERRUPTIBLE
);
3230 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3231 if (!map
|| !dm_table_get_size(map
))
3234 r
= __dm_resume(md
, map
);
3238 clear_bit(DMF_SUSPENDED
, &md
->flags
);
3242 mutex_unlock(&md
->suspend_lock
);
3248 * Internal suspend/resume works like userspace-driven suspend. It waits
3249 * until all bios finish and prevents issuing new bios to the target drivers.
3250 * It may be used only from the kernel.
3253 static void __dm_internal_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
3255 struct dm_table
*map
= NULL
;
3257 if (md
->internal_suspend_count
++)
3258 return; /* nested internal suspend */
3260 if (dm_suspended_md(md
)) {
3261 set_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3262 return; /* nest suspend */
3265 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3268 * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
3269 * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
3270 * would require changing .presuspend to return an error -- avoid this
3271 * until there is a need for more elaborate variants of internal suspend.
3273 (void) __dm_suspend(md
, map
, suspend_flags
, TASK_UNINTERRUPTIBLE
);
3275 set_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3277 dm_table_postsuspend_targets(map
);
3280 static void __dm_internal_resume(struct mapped_device
*md
)
3282 BUG_ON(!md
->internal_suspend_count
);
3284 if (--md
->internal_suspend_count
)
3285 return; /* resume from nested internal suspend */
3287 if (dm_suspended_md(md
))
3288 goto done
; /* resume from nested suspend */
3291 * NOTE: existing callers don't need to call dm_table_resume_targets
3292 * (which may fail -- so best to avoid it for now by passing NULL map)
3294 (void) __dm_resume(md
, NULL
);
3297 clear_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3298 smp_mb__after_atomic();
3299 wake_up_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
);
3302 void dm_internal_suspend_noflush(struct mapped_device
*md
)
3304 mutex_lock(&md
->suspend_lock
);
3305 __dm_internal_suspend(md
, DM_SUSPEND_NOFLUSH_FLAG
);
3306 mutex_unlock(&md
->suspend_lock
);
3308 EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush
);
3310 void dm_internal_resume(struct mapped_device
*md
)
3312 mutex_lock(&md
->suspend_lock
);
3313 __dm_internal_resume(md
);
3314 mutex_unlock(&md
->suspend_lock
);
3316 EXPORT_SYMBOL_GPL(dm_internal_resume
);
3319 * Fast variants of internal suspend/resume hold md->suspend_lock,
3320 * which prevents interaction with userspace-driven suspend.
3323 void dm_internal_suspend_fast(struct mapped_device
*md
)
3325 mutex_lock(&md
->suspend_lock
);
3326 if (dm_suspended_md(md
) || dm_suspended_internally_md(md
))
3329 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
3330 synchronize_srcu(&md
->io_barrier
);
3331 flush_workqueue(md
->wq
);
3332 dm_wait_for_completion(md
, TASK_UNINTERRUPTIBLE
);
3334 EXPORT_SYMBOL_GPL(dm_internal_suspend_fast
);
3336 void dm_internal_resume_fast(struct mapped_device
*md
)
3338 if (dm_suspended_md(md
) || dm_suspended_internally_md(md
))
3344 mutex_unlock(&md
->suspend_lock
);
3346 EXPORT_SYMBOL_GPL(dm_internal_resume_fast
);
3348 /*-----------------------------------------------------------------
3349 * Event notification.
3350 *---------------------------------------------------------------*/
3351 int dm_kobject_uevent(struct mapped_device
*md
, enum kobject_action action
,
3354 char udev_cookie
[DM_COOKIE_LENGTH
];
3355 char *envp
[] = { udev_cookie
, NULL
};
3358 return kobject_uevent(&disk_to_dev(md
->disk
)->kobj
, action
);
3360 snprintf(udev_cookie
, DM_COOKIE_LENGTH
, "%s=%u",
3361 DM_COOKIE_ENV_VAR_NAME
, cookie
);
3362 return kobject_uevent_env(&disk_to_dev(md
->disk
)->kobj
,
3367 uint32_t dm_next_uevent_seq(struct mapped_device
*md
)
3369 return atomic_add_return(1, &md
->uevent_seq
);
3372 uint32_t dm_get_event_nr(struct mapped_device
*md
)
3374 return atomic_read(&md
->event_nr
);
3377 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
3379 return wait_event_interruptible(md
->eventq
,
3380 (event_nr
!= atomic_read(&md
->event_nr
)));
3383 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
)
3385 unsigned long flags
;
3387 spin_lock_irqsave(&md
->uevent_lock
, flags
);
3388 list_add(elist
, &md
->uevent_list
);
3389 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
3393 * The gendisk is only valid as long as you have a reference
3396 struct gendisk
*dm_disk(struct mapped_device
*md
)
3400 EXPORT_SYMBOL_GPL(dm_disk
);
3402 struct kobject
*dm_kobject(struct mapped_device
*md
)
3404 return &md
->kobj_holder
.kobj
;
3407 struct mapped_device
*dm_get_from_kobject(struct kobject
*kobj
)
3409 struct mapped_device
*md
;
3411 md
= container_of(kobj
, struct mapped_device
, kobj_holder
.kobj
);
3413 if (test_bit(DMF_FREEING
, &md
->flags
) ||
3421 int dm_suspended_md(struct mapped_device
*md
)
3423 return test_bit(DMF_SUSPENDED
, &md
->flags
);
3426 int dm_suspended_internally_md(struct mapped_device
*md
)
3428 return test_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3431 int dm_test_deferred_remove_flag(struct mapped_device
*md
)
3433 return test_bit(DMF_DEFERRED_REMOVE
, &md
->flags
);
3436 int dm_suspended(struct dm_target
*ti
)
3438 return dm_suspended_md(dm_table_get_md(ti
->table
));
3440 EXPORT_SYMBOL_GPL(dm_suspended
);
3442 int dm_noflush_suspending(struct dm_target
*ti
)
3444 return __noflush_suspending(dm_table_get_md(ti
->table
));
3446 EXPORT_SYMBOL_GPL(dm_noflush_suspending
);
3448 struct dm_md_mempools
*dm_alloc_md_mempools(struct mapped_device
*md
, unsigned type
,
3449 unsigned integrity
, unsigned per_bio_data_size
)
3451 struct dm_md_mempools
*pools
= kzalloc(sizeof(*pools
), GFP_KERNEL
);
3452 struct kmem_cache
*cachep
= NULL
;
3453 unsigned int pool_size
= 0;
3454 unsigned int front_pad
;
3459 type
= filter_md_type(type
, md
);
3462 case DM_TYPE_BIO_BASED
:
3464 pool_size
= dm_get_reserved_bio_based_ios();
3465 front_pad
= roundup(per_bio_data_size
, __alignof__(struct dm_target_io
)) + offsetof(struct dm_target_io
, clone
);
3467 case DM_TYPE_REQUEST_BASED
:
3468 cachep
= _rq_tio_cache
;
3469 pool_size
= dm_get_reserved_rq_based_ios();
3470 pools
->rq_pool
= mempool_create_slab_pool(pool_size
, _rq_cache
);
3471 if (!pools
->rq_pool
)
3473 /* fall through to setup remaining rq-based pools */
3474 case DM_TYPE_MQ_REQUEST_BASED
:
3476 pool_size
= dm_get_reserved_rq_based_ios();
3477 front_pad
= offsetof(struct dm_rq_clone_bio_info
, clone
);
3478 /* per_bio_data_size is not used. See __bind_mempools(). */
3479 WARN_ON(per_bio_data_size
!= 0);
3486 pools
->io_pool
= mempool_create_slab_pool(pool_size
, cachep
);
3487 if (!pools
->io_pool
)
3491 pools
->bs
= bioset_create_nobvec(pool_size
, front_pad
);
3495 if (integrity
&& bioset_integrity_create(pools
->bs
, pool_size
))
3501 dm_free_md_mempools(pools
);
3506 void dm_free_md_mempools(struct dm_md_mempools
*pools
)
3512 mempool_destroy(pools
->io_pool
);
3515 mempool_destroy(pools
->rq_pool
);
3518 bioset_free(pools
->bs
);
3523 static const struct block_device_operations dm_blk_dops
= {
3524 .open
= dm_blk_open
,
3525 .release
= dm_blk_close
,
3526 .ioctl
= dm_blk_ioctl
,
3527 .getgeo
= dm_blk_getgeo
,
3528 .owner
= THIS_MODULE
3534 module_init(dm_init
);
3535 module_exit(dm_exit
);
3537 module_param(major
, uint
, 0);
3538 MODULE_PARM_DESC(major
, "The major number of the device mapper");
3540 module_param(reserved_bio_based_ios
, uint
, S_IRUGO
| S_IWUSR
);
3541 MODULE_PARM_DESC(reserved_bio_based_ios
, "Reserved IOs in bio-based mempools");
3543 module_param(reserved_rq_based_ios
, uint
, S_IRUGO
| S_IWUSR
);
3544 MODULE_PARM_DESC(reserved_rq_based_ios
, "Reserved IOs in request-based mempools");
3546 module_param(use_blk_mq
, bool, S_IRUGO
| S_IWUSR
);
3547 MODULE_PARM_DESC(use_blk_mq
, "Use block multiqueue for request-based DM devices");
3549 MODULE_DESCRIPTION(DM_NAME
" driver");
3550 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3551 MODULE_LICENSE("GPL");