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
;
1004 int error
= clone
->bi_error
;
1010 * An error has already been detected on the request.
1011 * Once error occurred, just let clone->end_io() handle
1017 * Don't notice the error to the upper layer yet.
1018 * The error handling decision is made by the target driver,
1019 * when the request is completed.
1026 * I/O for the bio successfully completed.
1027 * Notice the data completion to the upper layer.
1031 * bios are processed from the head of the list.
1032 * So the completing bio should always be rq->bio.
1033 * If it's not, something wrong is happening.
1035 if (tio
->orig
->bio
!= bio
)
1036 DMERR("bio completion is going in the middle of the request");
1039 * Update the original request.
1040 * Do not use blk_end_request() here, because it may complete
1041 * the original request before the clone, and break the ordering.
1043 blk_update_request(tio
->orig
, 0, nr_bytes
);
1046 static struct dm_rq_target_io
*tio_from_request(struct request
*rq
)
1048 return (rq
->q
->mq_ops
? blk_mq_rq_to_pdu(rq
) : rq
->special
);
1051 static void rq_end_stats(struct mapped_device
*md
, struct request
*orig
)
1053 if (unlikely(dm_stats_used(&md
->stats
))) {
1054 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
1055 tio
->duration_jiffies
= jiffies
- tio
->duration_jiffies
;
1056 dm_stats_account_io(&md
->stats
, orig
->cmd_flags
, blk_rq_pos(orig
),
1057 tio
->n_sectors
, true, tio
->duration_jiffies
,
1063 * Don't touch any member of the md after calling this function because
1064 * the md may be freed in dm_put() at the end of this function.
1065 * Or do dm_get() before calling this function and dm_put() later.
1067 static void rq_completed(struct mapped_device
*md
, int rw
, bool run_queue
)
1069 atomic_dec(&md
->pending
[rw
]);
1071 /* nudge anyone waiting on suspend queue */
1072 if (!md_in_flight(md
))
1076 * Run this off this callpath, as drivers could invoke end_io while
1077 * inside their request_fn (and holding the queue lock). Calling
1078 * back into ->request_fn() could deadlock attempting to grab the
1082 if (md
->queue
->mq_ops
)
1083 blk_mq_run_hw_queues(md
->queue
, true);
1085 blk_run_queue_async(md
->queue
);
1089 * dm_put() must be at the end of this function. See the comment above
1094 static void free_rq_clone(struct request
*clone
)
1096 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1097 struct mapped_device
*md
= tio
->md
;
1099 blk_rq_unprep_clone(clone
);
1101 if (md
->type
== DM_TYPE_MQ_REQUEST_BASED
)
1102 /* stacked on blk-mq queue(s) */
1103 tio
->ti
->type
->release_clone_rq(clone
);
1104 else if (!md
->queue
->mq_ops
)
1105 /* request_fn queue stacked on request_fn queue(s) */
1106 free_clone_request(md
, clone
);
1108 * NOTE: for the blk-mq queue stacked on request_fn queue(s) case:
1109 * no need to call free_clone_request() because we leverage blk-mq by
1110 * allocating the clone at the end of the blk-mq pdu (see: clone_rq)
1113 if (!md
->queue
->mq_ops
)
1118 * Complete the clone and the original request.
1119 * Must be called without clone's queue lock held,
1120 * see end_clone_request() for more details.
1122 static void dm_end_request(struct request
*clone
, int error
)
1124 int rw
= rq_data_dir(clone
);
1125 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1126 struct mapped_device
*md
= tio
->md
;
1127 struct request
*rq
= tio
->orig
;
1129 if (rq
->cmd_type
== REQ_TYPE_BLOCK_PC
) {
1130 rq
->errors
= clone
->errors
;
1131 rq
->resid_len
= clone
->resid_len
;
1135 * We are using the sense buffer of the original
1137 * So setting the length of the sense data is enough.
1139 rq
->sense_len
= clone
->sense_len
;
1142 free_rq_clone(clone
);
1143 rq_end_stats(md
, rq
);
1145 blk_end_request_all(rq
, error
);
1147 blk_mq_end_request(rq
, error
);
1148 rq_completed(md
, rw
, true);
1151 static void dm_unprep_request(struct request
*rq
)
1153 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
1154 struct request
*clone
= tio
->clone
;
1156 if (!rq
->q
->mq_ops
) {
1158 rq
->cmd_flags
&= ~REQ_DONTPREP
;
1162 free_rq_clone(clone
);
1166 * Requeue the original request of a clone.
1168 static void old_requeue_request(struct request
*rq
)
1170 struct request_queue
*q
= rq
->q
;
1171 unsigned long flags
;
1173 spin_lock_irqsave(q
->queue_lock
, flags
);
1174 blk_requeue_request(q
, rq
);
1175 blk_run_queue_async(q
);
1176 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1179 static void dm_requeue_original_request(struct mapped_device
*md
,
1182 int rw
= rq_data_dir(rq
);
1184 dm_unprep_request(rq
);
1186 rq_end_stats(md
, rq
);
1188 old_requeue_request(rq
);
1190 blk_mq_requeue_request(rq
);
1191 blk_mq_kick_requeue_list(rq
->q
);
1194 rq_completed(md
, rw
, false);
1197 static void old_stop_queue(struct request_queue
*q
)
1199 unsigned long flags
;
1201 if (blk_queue_stopped(q
))
1204 spin_lock_irqsave(q
->queue_lock
, flags
);
1206 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1209 static void stop_queue(struct request_queue
*q
)
1214 blk_mq_stop_hw_queues(q
);
1217 static void old_start_queue(struct request_queue
*q
)
1219 unsigned long flags
;
1221 spin_lock_irqsave(q
->queue_lock
, flags
);
1222 if (blk_queue_stopped(q
))
1224 spin_unlock_irqrestore(q
->queue_lock
, flags
);
1227 static void start_queue(struct request_queue
*q
)
1232 blk_mq_start_stopped_hw_queues(q
, true);
1235 static void dm_done(struct request
*clone
, int error
, bool mapped
)
1238 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1239 dm_request_endio_fn rq_end_io
= NULL
;
1242 rq_end_io
= tio
->ti
->type
->rq_end_io
;
1244 if (mapped
&& rq_end_io
)
1245 r
= rq_end_io(tio
->ti
, clone
, error
, &tio
->info
);
1248 if (unlikely(r
== -EREMOTEIO
&& (clone
->cmd_flags
& REQ_WRITE_SAME
) &&
1249 !clone
->q
->limits
.max_write_same_sectors
))
1250 disable_write_same(tio
->md
);
1253 /* The target wants to complete the I/O */
1254 dm_end_request(clone
, r
);
1255 else if (r
== DM_ENDIO_INCOMPLETE
)
1256 /* The target will handle the I/O */
1258 else if (r
== DM_ENDIO_REQUEUE
)
1259 /* The target wants to requeue the I/O */
1260 dm_requeue_original_request(tio
->md
, tio
->orig
);
1262 DMWARN("unimplemented target endio return value: %d", r
);
1268 * Request completion handler for request-based dm
1270 static void dm_softirq_done(struct request
*rq
)
1273 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
1274 struct request
*clone
= tio
->clone
;
1278 rq_end_stats(tio
->md
, rq
);
1279 rw
= rq_data_dir(rq
);
1280 if (!rq
->q
->mq_ops
) {
1281 blk_end_request_all(rq
, tio
->error
);
1282 rq_completed(tio
->md
, rw
, false);
1285 blk_mq_end_request(rq
, tio
->error
);
1286 rq_completed(tio
->md
, rw
, false);
1291 if (rq
->cmd_flags
& REQ_FAILED
)
1294 dm_done(clone
, tio
->error
, mapped
);
1298 * Complete the clone and the original request with the error status
1299 * through softirq context.
1301 static void dm_complete_request(struct request
*rq
, int error
)
1303 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
1306 blk_complete_request(rq
);
1310 * Complete the not-mapped clone and the original request with the error status
1311 * through softirq context.
1312 * Target's rq_end_io() function isn't called.
1313 * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
1315 static void dm_kill_unmapped_request(struct request
*rq
, int error
)
1317 rq
->cmd_flags
|= REQ_FAILED
;
1318 dm_complete_request(rq
, error
);
1322 * Called with the clone's queue lock held (for non-blk-mq)
1324 static void end_clone_request(struct request
*clone
, int error
)
1326 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
1328 if (!clone
->q
->mq_ops
) {
1330 * For just cleaning up the information of the queue in which
1331 * the clone was dispatched.
1332 * The clone is *NOT* freed actually here because it is alloced
1333 * from dm own mempool (REQ_ALLOCED isn't set).
1335 __blk_put_request(clone
->q
, clone
);
1339 * Actual request completion is done in a softirq context which doesn't
1340 * hold the clone's queue lock. Otherwise, deadlock could occur because:
1341 * - another request may be submitted by the upper level driver
1342 * of the stacking during the completion
1343 * - the submission which requires queue lock may be done
1344 * against this clone's queue
1346 dm_complete_request(tio
->orig
, error
);
1350 * Return maximum size of I/O possible at the supplied sector up to the current
1353 static sector_t
max_io_len_target_boundary(sector_t sector
, struct dm_target
*ti
)
1355 sector_t target_offset
= dm_target_offset(ti
, sector
);
1357 return ti
->len
- target_offset
;
1360 static sector_t
max_io_len(sector_t sector
, struct dm_target
*ti
)
1362 sector_t len
= max_io_len_target_boundary(sector
, ti
);
1363 sector_t offset
, max_len
;
1366 * Does the target need to split even further?
1368 if (ti
->max_io_len
) {
1369 offset
= dm_target_offset(ti
, sector
);
1370 if (unlikely(ti
->max_io_len
& (ti
->max_io_len
- 1)))
1371 max_len
= sector_div(offset
, ti
->max_io_len
);
1373 max_len
= offset
& (ti
->max_io_len
- 1);
1374 max_len
= ti
->max_io_len
- max_len
;
1383 int dm_set_target_max_io_len(struct dm_target
*ti
, sector_t len
)
1385 if (len
> UINT_MAX
) {
1386 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
1387 (unsigned long long)len
, UINT_MAX
);
1388 ti
->error
= "Maximum size of target IO is too large";
1392 ti
->max_io_len
= (uint32_t) len
;
1396 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len
);
1399 * A target may call dm_accept_partial_bio only from the map routine. It is
1400 * allowed for all bio types except REQ_FLUSH.
1402 * dm_accept_partial_bio informs the dm that the target only wants to process
1403 * additional n_sectors sectors of the bio and the rest of the data should be
1404 * sent in a next bio.
1406 * A diagram that explains the arithmetics:
1407 * +--------------------+---------------+-------+
1409 * +--------------------+---------------+-------+
1411 * <-------------- *tio->len_ptr --------------->
1412 * <------- bi_size ------->
1415 * Region 1 was already iterated over with bio_advance or similar function.
1416 * (it may be empty if the target doesn't use bio_advance)
1417 * Region 2 is the remaining bio size that the target wants to process.
1418 * (it may be empty if region 1 is non-empty, although there is no reason
1420 * The target requires that region 3 is to be sent in the next bio.
1422 * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
1423 * the partially processed part (the sum of regions 1+2) must be the same for all
1424 * copies of the bio.
1426 void dm_accept_partial_bio(struct bio
*bio
, unsigned n_sectors
)
1428 struct dm_target_io
*tio
= container_of(bio
, struct dm_target_io
, clone
);
1429 unsigned bi_size
= bio
->bi_iter
.bi_size
>> SECTOR_SHIFT
;
1430 BUG_ON(bio
->bi_rw
& REQ_FLUSH
);
1431 BUG_ON(bi_size
> *tio
->len_ptr
);
1432 BUG_ON(n_sectors
> bi_size
);
1433 *tio
->len_ptr
-= bi_size
- n_sectors
;
1434 bio
->bi_iter
.bi_size
= n_sectors
<< SECTOR_SHIFT
;
1436 EXPORT_SYMBOL_GPL(dm_accept_partial_bio
);
1438 static void __map_bio(struct dm_target_io
*tio
)
1442 struct mapped_device
*md
;
1443 struct bio
*clone
= &tio
->clone
;
1444 struct dm_target
*ti
= tio
->ti
;
1446 clone
->bi_end_io
= clone_endio
;
1449 * Map the clone. If r == 0 we don't need to do
1450 * anything, the target has assumed ownership of
1453 atomic_inc(&tio
->io
->io_count
);
1454 sector
= clone
->bi_iter
.bi_sector
;
1455 r
= ti
->type
->map(ti
, clone
);
1456 if (r
== DM_MAPIO_REMAPPED
) {
1457 /* the bio has been remapped so dispatch it */
1459 trace_block_bio_remap(bdev_get_queue(clone
->bi_bdev
), clone
,
1460 tio
->io
->bio
->bi_bdev
->bd_dev
, sector
);
1462 generic_make_request(clone
);
1463 } else if (r
< 0 || r
== DM_MAPIO_REQUEUE
) {
1464 /* error the io and bail out, or requeue it if needed */
1466 dec_pending(tio
->io
, r
);
1468 } else if (r
!= DM_MAPIO_SUBMITTED
) {
1469 DMWARN("unimplemented target map return value: %d", r
);
1475 struct mapped_device
*md
;
1476 struct dm_table
*map
;
1480 unsigned sector_count
;
1483 static void bio_setup_sector(struct bio
*bio
, sector_t sector
, unsigned len
)
1485 bio
->bi_iter
.bi_sector
= sector
;
1486 bio
->bi_iter
.bi_size
= to_bytes(len
);
1490 * Creates a bio that consists of range of complete bvecs.
1492 static void clone_bio(struct dm_target_io
*tio
, struct bio
*bio
,
1493 sector_t sector
, unsigned len
)
1495 struct bio
*clone
= &tio
->clone
;
1497 __bio_clone_fast(clone
, bio
);
1499 if (bio_integrity(bio
))
1500 bio_integrity_clone(clone
, bio
, GFP_NOIO
);
1502 bio_advance(clone
, to_bytes(sector
- clone
->bi_iter
.bi_sector
));
1503 clone
->bi_iter
.bi_size
= to_bytes(len
);
1505 if (bio_integrity(bio
))
1506 bio_integrity_trim(clone
, 0, len
);
1509 static struct dm_target_io
*alloc_tio(struct clone_info
*ci
,
1510 struct dm_target
*ti
,
1511 unsigned target_bio_nr
)
1513 struct dm_target_io
*tio
;
1516 clone
= bio_alloc_bioset(GFP_NOIO
, 0, ci
->md
->bs
);
1517 tio
= container_of(clone
, struct dm_target_io
, clone
);
1521 tio
->target_bio_nr
= target_bio_nr
;
1526 static void __clone_and_map_simple_bio(struct clone_info
*ci
,
1527 struct dm_target
*ti
,
1528 unsigned target_bio_nr
, unsigned *len
)
1530 struct dm_target_io
*tio
= alloc_tio(ci
, ti
, target_bio_nr
);
1531 struct bio
*clone
= &tio
->clone
;
1535 __bio_clone_fast(clone
, ci
->bio
);
1537 bio_setup_sector(clone
, ci
->sector
, *len
);
1542 static void __send_duplicate_bios(struct clone_info
*ci
, struct dm_target
*ti
,
1543 unsigned num_bios
, unsigned *len
)
1545 unsigned target_bio_nr
;
1547 for (target_bio_nr
= 0; target_bio_nr
< num_bios
; target_bio_nr
++)
1548 __clone_and_map_simple_bio(ci
, ti
, target_bio_nr
, len
);
1551 static int __send_empty_flush(struct clone_info
*ci
)
1553 unsigned target_nr
= 0;
1554 struct dm_target
*ti
;
1556 BUG_ON(bio_has_data(ci
->bio
));
1557 while ((ti
= dm_table_get_target(ci
->map
, target_nr
++)))
1558 __send_duplicate_bios(ci
, ti
, ti
->num_flush_bios
, NULL
);
1563 static void __clone_and_map_data_bio(struct clone_info
*ci
, struct dm_target
*ti
,
1564 sector_t sector
, unsigned *len
)
1566 struct bio
*bio
= ci
->bio
;
1567 struct dm_target_io
*tio
;
1568 unsigned target_bio_nr
;
1569 unsigned num_target_bios
= 1;
1572 * Does the target want to receive duplicate copies of the bio?
1574 if (bio_data_dir(bio
) == WRITE
&& ti
->num_write_bios
)
1575 num_target_bios
= ti
->num_write_bios(ti
, bio
);
1577 for (target_bio_nr
= 0; target_bio_nr
< num_target_bios
; target_bio_nr
++) {
1578 tio
= alloc_tio(ci
, ti
, target_bio_nr
);
1580 clone_bio(tio
, bio
, sector
, *len
);
1585 typedef unsigned (*get_num_bios_fn
)(struct dm_target
*ti
);
1587 static unsigned get_num_discard_bios(struct dm_target
*ti
)
1589 return ti
->num_discard_bios
;
1592 static unsigned get_num_write_same_bios(struct dm_target
*ti
)
1594 return ti
->num_write_same_bios
;
1597 typedef bool (*is_split_required_fn
)(struct dm_target
*ti
);
1599 static bool is_split_required_for_discard(struct dm_target
*ti
)
1601 return ti
->split_discard_bios
;
1604 static int __send_changing_extent_only(struct clone_info
*ci
,
1605 get_num_bios_fn get_num_bios
,
1606 is_split_required_fn is_split_required
)
1608 struct dm_target
*ti
;
1613 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1614 if (!dm_target_is_valid(ti
))
1618 * Even though the device advertised support for this type of
1619 * request, that does not mean every target supports it, and
1620 * reconfiguration might also have changed that since the
1621 * check was performed.
1623 num_bios
= get_num_bios
? get_num_bios(ti
) : 0;
1627 if (is_split_required
&& !is_split_required(ti
))
1628 len
= min((sector_t
)ci
->sector_count
, max_io_len_target_boundary(ci
->sector
, ti
));
1630 len
= min((sector_t
)ci
->sector_count
, max_io_len(ci
->sector
, ti
));
1632 __send_duplicate_bios(ci
, ti
, num_bios
, &len
);
1635 } while (ci
->sector_count
-= len
);
1640 static int __send_discard(struct clone_info
*ci
)
1642 return __send_changing_extent_only(ci
, get_num_discard_bios
,
1643 is_split_required_for_discard
);
1646 static int __send_write_same(struct clone_info
*ci
)
1648 return __send_changing_extent_only(ci
, get_num_write_same_bios
, NULL
);
1652 * Select the correct strategy for processing a non-flush bio.
1654 static int __split_and_process_non_flush(struct clone_info
*ci
)
1656 struct bio
*bio
= ci
->bio
;
1657 struct dm_target
*ti
;
1660 if (unlikely(bio
->bi_rw
& REQ_DISCARD
))
1661 return __send_discard(ci
);
1662 else if (unlikely(bio
->bi_rw
& REQ_WRITE_SAME
))
1663 return __send_write_same(ci
);
1665 ti
= dm_table_find_target(ci
->map
, ci
->sector
);
1666 if (!dm_target_is_valid(ti
))
1669 len
= min_t(sector_t
, max_io_len(ci
->sector
, ti
), ci
->sector_count
);
1671 __clone_and_map_data_bio(ci
, ti
, ci
->sector
, &len
);
1674 ci
->sector_count
-= len
;
1680 * Entry point to split a bio into clones and submit them to the targets.
1682 static void __split_and_process_bio(struct mapped_device
*md
,
1683 struct dm_table
*map
, struct bio
*bio
)
1685 struct clone_info ci
;
1688 if (unlikely(!map
)) {
1695 ci
.io
= alloc_io(md
);
1697 atomic_set(&ci
.io
->io_count
, 1);
1700 spin_lock_init(&ci
.io
->endio_lock
);
1701 ci
.sector
= bio
->bi_iter
.bi_sector
;
1703 start_io_acct(ci
.io
);
1705 if (bio
->bi_rw
& REQ_FLUSH
) {
1706 ci
.bio
= &ci
.md
->flush_bio
;
1707 ci
.sector_count
= 0;
1708 error
= __send_empty_flush(&ci
);
1709 /* dec_pending submits any data associated with flush */
1712 ci
.sector_count
= bio_sectors(bio
);
1713 while (ci
.sector_count
&& !error
)
1714 error
= __split_and_process_non_flush(&ci
);
1717 /* drop the extra reference count */
1718 dec_pending(ci
.io
, error
);
1720 /*-----------------------------------------------------------------
1722 *---------------------------------------------------------------*/
1725 * The request function that just remaps the bio built up by
1728 static void dm_make_request(struct request_queue
*q
, struct bio
*bio
)
1730 int rw
= bio_data_dir(bio
);
1731 struct mapped_device
*md
= q
->queuedata
;
1733 struct dm_table
*map
;
1735 map
= dm_get_live_table(md
, &srcu_idx
);
1737 blk_queue_split(q
, &bio
, q
->bio_split
);
1739 generic_start_io_acct(rw
, bio_sectors(bio
), &dm_disk(md
)->part0
);
1741 /* if we're suspended, we have to queue this io for later */
1742 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
))) {
1743 dm_put_live_table(md
, srcu_idx
);
1745 if (bio_rw(bio
) != READA
)
1752 __split_and_process_bio(md
, map
, bio
);
1753 dm_put_live_table(md
, srcu_idx
);
1757 int dm_request_based(struct mapped_device
*md
)
1759 return blk_queue_stackable(md
->queue
);
1762 static void dm_dispatch_clone_request(struct request
*clone
, struct request
*rq
)
1766 if (blk_queue_io_stat(clone
->q
))
1767 clone
->cmd_flags
|= REQ_IO_STAT
;
1769 clone
->start_time
= jiffies
;
1770 r
= blk_insert_cloned_request(clone
->q
, clone
);
1772 /* must complete clone in terms of original request */
1773 dm_complete_request(rq
, r
);
1776 static int dm_rq_bio_constructor(struct bio
*bio
, struct bio
*bio_orig
,
1779 struct dm_rq_target_io
*tio
= data
;
1780 struct dm_rq_clone_bio_info
*info
=
1781 container_of(bio
, struct dm_rq_clone_bio_info
, clone
);
1783 info
->orig
= bio_orig
;
1785 bio
->bi_end_io
= end_clone_bio
;
1790 static int setup_clone(struct request
*clone
, struct request
*rq
,
1791 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
1795 r
= blk_rq_prep_clone(clone
, rq
, tio
->md
->bs
, gfp_mask
,
1796 dm_rq_bio_constructor
, tio
);
1800 clone
->cmd
= rq
->cmd
;
1801 clone
->cmd_len
= rq
->cmd_len
;
1802 clone
->sense
= rq
->sense
;
1803 clone
->end_io
= end_clone_request
;
1804 clone
->end_io_data
= tio
;
1811 static struct request
*clone_rq(struct request
*rq
, struct mapped_device
*md
,
1812 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
1815 * Do not allocate a clone if tio->clone was already set
1816 * (see: dm_mq_queue_rq).
1818 bool alloc_clone
= !tio
->clone
;
1819 struct request
*clone
;
1822 clone
= alloc_clone_request(md
, gfp_mask
);
1828 blk_rq_init(NULL
, clone
);
1829 if (setup_clone(clone
, rq
, tio
, gfp_mask
)) {
1832 free_clone_request(md
, clone
);
1839 static void map_tio_request(struct kthread_work
*work
);
1841 static void init_tio(struct dm_rq_target_io
*tio
, struct request
*rq
,
1842 struct mapped_device
*md
)
1849 memset(&tio
->info
, 0, sizeof(tio
->info
));
1850 if (md
->kworker_task
)
1851 init_kthread_work(&tio
->work
, map_tio_request
);
1854 static struct dm_rq_target_io
*prep_tio(struct request
*rq
,
1855 struct mapped_device
*md
, gfp_t gfp_mask
)
1857 struct dm_rq_target_io
*tio
;
1859 struct dm_table
*table
;
1861 tio
= alloc_rq_tio(md
, gfp_mask
);
1865 init_tio(tio
, rq
, md
);
1867 table
= dm_get_live_table(md
, &srcu_idx
);
1868 if (!dm_table_mq_request_based(table
)) {
1869 if (!clone_rq(rq
, md
, tio
, gfp_mask
)) {
1870 dm_put_live_table(md
, srcu_idx
);
1875 dm_put_live_table(md
, srcu_idx
);
1881 * Called with the queue lock held.
1883 static int dm_prep_fn(struct request_queue
*q
, struct request
*rq
)
1885 struct mapped_device
*md
= q
->queuedata
;
1886 struct dm_rq_target_io
*tio
;
1888 if (unlikely(rq
->special
)) {
1889 DMWARN("Already has something in rq->special.");
1890 return BLKPREP_KILL
;
1893 tio
= prep_tio(rq
, md
, GFP_ATOMIC
);
1895 return BLKPREP_DEFER
;
1898 rq
->cmd_flags
|= REQ_DONTPREP
;
1905 * 0 : the request has been processed
1906 * DM_MAPIO_REQUEUE : the original request needs to be requeued
1907 * < 0 : the request was completed due to failure
1909 static int map_request(struct dm_rq_target_io
*tio
, struct request
*rq
,
1910 struct mapped_device
*md
)
1913 struct dm_target
*ti
= tio
->ti
;
1914 struct request
*clone
= NULL
;
1918 r
= ti
->type
->map_rq(ti
, clone
, &tio
->info
);
1920 r
= ti
->type
->clone_and_map_rq(ti
, rq
, &tio
->info
, &clone
);
1922 /* The target wants to complete the I/O */
1923 dm_kill_unmapped_request(rq
, r
);
1926 if (r
!= DM_MAPIO_REMAPPED
)
1928 if (setup_clone(clone
, rq
, tio
, GFP_ATOMIC
)) {
1930 ti
->type
->release_clone_rq(clone
);
1931 return DM_MAPIO_REQUEUE
;
1936 case DM_MAPIO_SUBMITTED
:
1937 /* The target has taken the I/O to submit by itself later */
1939 case DM_MAPIO_REMAPPED
:
1940 /* The target has remapped the I/O so dispatch it */
1941 trace_block_rq_remap(clone
->q
, clone
, disk_devt(dm_disk(md
)),
1943 dm_dispatch_clone_request(clone
, rq
);
1945 case DM_MAPIO_REQUEUE
:
1946 /* The target wants to requeue the I/O */
1947 dm_requeue_original_request(md
, tio
->orig
);
1951 DMWARN("unimplemented target map return value: %d", r
);
1955 /* The target wants to complete the I/O */
1956 dm_kill_unmapped_request(rq
, r
);
1963 static void map_tio_request(struct kthread_work
*work
)
1965 struct dm_rq_target_io
*tio
= container_of(work
, struct dm_rq_target_io
, work
);
1966 struct request
*rq
= tio
->orig
;
1967 struct mapped_device
*md
= tio
->md
;
1969 if (map_request(tio
, rq
, md
) == DM_MAPIO_REQUEUE
)
1970 dm_requeue_original_request(md
, rq
);
1973 static void dm_start_request(struct mapped_device
*md
, struct request
*orig
)
1975 if (!orig
->q
->mq_ops
)
1976 blk_start_request(orig
);
1978 blk_mq_start_request(orig
);
1979 atomic_inc(&md
->pending
[rq_data_dir(orig
)]);
1981 if (md
->seq_rq_merge_deadline_usecs
) {
1982 md
->last_rq_pos
= rq_end_sector(orig
);
1983 md
->last_rq_rw
= rq_data_dir(orig
);
1984 md
->last_rq_start_time
= ktime_get();
1987 if (unlikely(dm_stats_used(&md
->stats
))) {
1988 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
1989 tio
->duration_jiffies
= jiffies
;
1990 tio
->n_sectors
= blk_rq_sectors(orig
);
1991 dm_stats_account_io(&md
->stats
, orig
->cmd_flags
, blk_rq_pos(orig
),
1992 tio
->n_sectors
, false, 0, &tio
->stats_aux
);
1996 * Hold the md reference here for the in-flight I/O.
1997 * We can't rely on the reference count by device opener,
1998 * because the device may be closed during the request completion
1999 * when all bios are completed.
2000 * See the comment in rq_completed() too.
2005 #define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
2007 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device
*md
, char *buf
)
2009 return sprintf(buf
, "%u\n", md
->seq_rq_merge_deadline_usecs
);
2012 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device
*md
,
2013 const char *buf
, size_t count
)
2017 if (!dm_request_based(md
) || md
->use_blk_mq
)
2020 if (kstrtouint(buf
, 10, &deadline
))
2023 if (deadline
> MAX_SEQ_RQ_MERGE_DEADLINE_USECS
)
2024 deadline
= MAX_SEQ_RQ_MERGE_DEADLINE_USECS
;
2026 md
->seq_rq_merge_deadline_usecs
= deadline
;
2031 static bool dm_request_peeked_before_merge_deadline(struct mapped_device
*md
)
2033 ktime_t kt_deadline
;
2035 if (!md
->seq_rq_merge_deadline_usecs
)
2038 kt_deadline
= ns_to_ktime((u64
)md
->seq_rq_merge_deadline_usecs
* NSEC_PER_USEC
);
2039 kt_deadline
= ktime_add_safe(md
->last_rq_start_time
, kt_deadline
);
2041 return !ktime_after(ktime_get(), kt_deadline
);
2045 * q->request_fn for request-based dm.
2046 * Called with the queue lock held.
2048 static void dm_request_fn(struct request_queue
*q
)
2050 struct mapped_device
*md
= q
->queuedata
;
2052 struct dm_table
*map
= dm_get_live_table(md
, &srcu_idx
);
2053 struct dm_target
*ti
;
2055 struct dm_rq_target_io
*tio
;
2059 * For suspend, check blk_queue_stopped() and increment
2060 * ->pending within a single queue_lock not to increment the
2061 * number of in-flight I/Os after the queue is stopped in
2064 while (!blk_queue_stopped(q
)) {
2065 rq
= blk_peek_request(q
);
2069 /* always use block 0 to find the target for flushes for now */
2071 if (!(rq
->cmd_flags
& REQ_FLUSH
))
2072 pos
= blk_rq_pos(rq
);
2074 ti
= dm_table_find_target(map
, pos
);
2075 if (!dm_target_is_valid(ti
)) {
2077 * Must perform setup, that rq_completed() requires,
2078 * before calling dm_kill_unmapped_request
2080 DMERR_LIMIT("request attempted access beyond the end of device");
2081 dm_start_request(md
, rq
);
2082 dm_kill_unmapped_request(rq
, -EIO
);
2086 if (dm_request_peeked_before_merge_deadline(md
) &&
2087 md_in_flight(md
) && rq
->bio
&& rq
->bio
->bi_vcnt
== 1 &&
2088 md
->last_rq_pos
== pos
&& md
->last_rq_rw
== rq_data_dir(rq
))
2091 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
2094 dm_start_request(md
, rq
);
2096 tio
= tio_from_request(rq
);
2097 /* Establish tio->ti before queuing work (map_tio_request) */
2099 queue_kthread_work(&md
->kworker
, &tio
->work
);
2100 BUG_ON(!irqs_disabled());
2106 blk_delay_queue(q
, HZ
/ 100);
2108 dm_put_live_table(md
, srcu_idx
);
2111 static int dm_any_congested(void *congested_data
, int bdi_bits
)
2114 struct mapped_device
*md
= congested_data
;
2115 struct dm_table
*map
;
2117 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2118 map
= dm_get_live_table_fast(md
);
2121 * Request-based dm cares about only own queue for
2122 * the query about congestion status of request_queue
2124 if (dm_request_based(md
))
2125 r
= md
->queue
->backing_dev_info
.wb
.state
&
2128 r
= dm_table_any_congested(map
, bdi_bits
);
2130 dm_put_live_table_fast(md
);
2136 /*-----------------------------------------------------------------
2137 * An IDR is used to keep track of allocated minor numbers.
2138 *---------------------------------------------------------------*/
2139 static void free_minor(int minor
)
2141 spin_lock(&_minor_lock
);
2142 idr_remove(&_minor_idr
, minor
);
2143 spin_unlock(&_minor_lock
);
2147 * See if the device with a specific minor # is free.
2149 static int specific_minor(int minor
)
2153 if (minor
>= (1 << MINORBITS
))
2156 idr_preload(GFP_KERNEL
);
2157 spin_lock(&_minor_lock
);
2159 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, minor
, minor
+ 1, GFP_NOWAIT
);
2161 spin_unlock(&_minor_lock
);
2164 return r
== -ENOSPC
? -EBUSY
: r
;
2168 static int next_free_minor(int *minor
)
2172 idr_preload(GFP_KERNEL
);
2173 spin_lock(&_minor_lock
);
2175 r
= idr_alloc(&_minor_idr
, MINOR_ALLOCED
, 0, 1 << MINORBITS
, GFP_NOWAIT
);
2177 spin_unlock(&_minor_lock
);
2185 static const struct block_device_operations dm_blk_dops
;
2187 static void dm_wq_work(struct work_struct
*work
);
2189 static void dm_init_md_queue(struct mapped_device
*md
)
2192 * Request-based dm devices cannot be stacked on top of bio-based dm
2193 * devices. The type of this dm device may not have been decided yet.
2194 * The type is decided at the first table loading time.
2195 * To prevent problematic device stacking, clear the queue flag
2196 * for request stacking support until then.
2198 * This queue is new, so no concurrency on the queue_flags.
2200 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE
, md
->queue
);
2203 static void dm_init_old_md_queue(struct mapped_device
*md
)
2205 md
->use_blk_mq
= false;
2206 dm_init_md_queue(md
);
2209 * Initialize aspects of queue that aren't relevant for blk-mq
2211 md
->queue
->queuedata
= md
;
2212 md
->queue
->backing_dev_info
.congested_fn
= dm_any_congested
;
2213 md
->queue
->backing_dev_info
.congested_data
= md
;
2215 blk_queue_bounce_limit(md
->queue
, BLK_BOUNCE_ANY
);
2218 static void cleanup_mapped_device(struct mapped_device
*md
)
2221 destroy_workqueue(md
->wq
);
2222 if (md
->kworker_task
)
2223 kthread_stop(md
->kworker_task
);
2225 mempool_destroy(md
->io_pool
);
2227 mempool_destroy(md
->rq_pool
);
2229 bioset_free(md
->bs
);
2231 cleanup_srcu_struct(&md
->io_barrier
);
2234 spin_lock(&_minor_lock
);
2235 md
->disk
->private_data
= NULL
;
2236 spin_unlock(&_minor_lock
);
2237 if (blk_get_integrity(md
->disk
))
2238 blk_integrity_unregister(md
->disk
);
2239 del_gendisk(md
->disk
);
2244 blk_cleanup_queue(md
->queue
);
2253 * Allocate and initialise a blank device with a given minor.
2255 static struct mapped_device
*alloc_dev(int minor
)
2258 struct mapped_device
*md
= kzalloc(sizeof(*md
), GFP_KERNEL
);
2262 DMWARN("unable to allocate device, out of memory.");
2266 if (!try_module_get(THIS_MODULE
))
2267 goto bad_module_get
;
2269 /* get a minor number for the dev */
2270 if (minor
== DM_ANY_MINOR
)
2271 r
= next_free_minor(&minor
);
2273 r
= specific_minor(minor
);
2277 r
= init_srcu_struct(&md
->io_barrier
);
2279 goto bad_io_barrier
;
2281 md
->use_blk_mq
= use_blk_mq
;
2282 md
->type
= DM_TYPE_NONE
;
2283 mutex_init(&md
->suspend_lock
);
2284 mutex_init(&md
->type_lock
);
2285 mutex_init(&md
->table_devices_lock
);
2286 spin_lock_init(&md
->deferred_lock
);
2287 atomic_set(&md
->holders
, 1);
2288 atomic_set(&md
->open_count
, 0);
2289 atomic_set(&md
->event_nr
, 0);
2290 atomic_set(&md
->uevent_seq
, 0);
2291 INIT_LIST_HEAD(&md
->uevent_list
);
2292 INIT_LIST_HEAD(&md
->table_devices
);
2293 spin_lock_init(&md
->uevent_lock
);
2295 md
->queue
= blk_alloc_queue(GFP_KERNEL
);
2299 dm_init_md_queue(md
);
2301 md
->disk
= alloc_disk(1);
2305 atomic_set(&md
->pending
[0], 0);
2306 atomic_set(&md
->pending
[1], 0);
2307 init_waitqueue_head(&md
->wait
);
2308 INIT_WORK(&md
->work
, dm_wq_work
);
2309 init_waitqueue_head(&md
->eventq
);
2310 init_completion(&md
->kobj_holder
.completion
);
2311 md
->kworker_task
= NULL
;
2313 md
->disk
->major
= _major
;
2314 md
->disk
->first_minor
= minor
;
2315 md
->disk
->fops
= &dm_blk_dops
;
2316 md
->disk
->queue
= md
->queue
;
2317 md
->disk
->private_data
= md
;
2318 sprintf(md
->disk
->disk_name
, "dm-%d", minor
);
2320 format_dev_t(md
->name
, MKDEV(_major
, minor
));
2322 md
->wq
= alloc_workqueue("kdmflush", WQ_MEM_RECLAIM
, 0);
2326 md
->bdev
= bdget_disk(md
->disk
, 0);
2330 bio_init(&md
->flush_bio
);
2331 md
->flush_bio
.bi_bdev
= md
->bdev
;
2332 md
->flush_bio
.bi_rw
= WRITE_FLUSH
;
2334 dm_stats_init(&md
->stats
);
2336 /* Populate the mapping, nobody knows we exist yet */
2337 spin_lock(&_minor_lock
);
2338 old_md
= idr_replace(&_minor_idr
, md
, minor
);
2339 spin_unlock(&_minor_lock
);
2341 BUG_ON(old_md
!= MINOR_ALLOCED
);
2346 cleanup_mapped_device(md
);
2350 module_put(THIS_MODULE
);
2356 static void unlock_fs(struct mapped_device
*md
);
2358 static void free_dev(struct mapped_device
*md
)
2360 int minor
= MINOR(disk_devt(md
->disk
));
2364 cleanup_mapped_device(md
);
2366 blk_mq_free_tag_set(&md
->tag_set
);
2368 free_table_devices(&md
->table_devices
);
2369 dm_stats_cleanup(&md
->stats
);
2372 module_put(THIS_MODULE
);
2376 static void __bind_mempools(struct mapped_device
*md
, struct dm_table
*t
)
2378 struct dm_md_mempools
*p
= dm_table_get_md_mempools(t
);
2381 /* The md already has necessary mempools. */
2382 if (dm_table_get_type(t
) == DM_TYPE_BIO_BASED
) {
2384 * Reload bioset because front_pad may have changed
2385 * because a different table was loaded.
2387 bioset_free(md
->bs
);
2392 * There's no need to reload with request-based dm
2393 * because the size of front_pad doesn't change.
2394 * Note for future: If you are to reload bioset,
2395 * prep-ed requests in the queue may refer
2396 * to bio from the old bioset, so you must walk
2397 * through the queue to unprep.
2402 BUG_ON(!p
|| md
->io_pool
|| md
->rq_pool
|| md
->bs
);
2404 md
->io_pool
= p
->io_pool
;
2406 md
->rq_pool
= p
->rq_pool
;
2412 /* mempool bind completed, no longer need any mempools in the table */
2413 dm_table_free_md_mempools(t
);
2417 * Bind a table to the device.
2419 static void event_callback(void *context
)
2421 unsigned long flags
;
2423 struct mapped_device
*md
= (struct mapped_device
*) context
;
2425 spin_lock_irqsave(&md
->uevent_lock
, flags
);
2426 list_splice_init(&md
->uevent_list
, &uevents
);
2427 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
2429 dm_send_uevents(&uevents
, &disk_to_dev(md
->disk
)->kobj
);
2431 atomic_inc(&md
->event_nr
);
2432 wake_up(&md
->eventq
);
2436 * Protected by md->suspend_lock obtained by dm_swap_table().
2438 static void __set_size(struct mapped_device
*md
, sector_t size
)
2440 set_capacity(md
->disk
, size
);
2442 i_size_write(md
->bdev
->bd_inode
, (loff_t
)size
<< SECTOR_SHIFT
);
2446 * Returns old map, which caller must destroy.
2448 static struct dm_table
*__bind(struct mapped_device
*md
, struct dm_table
*t
,
2449 struct queue_limits
*limits
)
2451 struct dm_table
*old_map
;
2452 struct request_queue
*q
= md
->queue
;
2455 size
= dm_table_get_size(t
);
2458 * Wipe any geometry if the size of the table changed.
2460 if (size
!= dm_get_size(md
))
2461 memset(&md
->geometry
, 0, sizeof(md
->geometry
));
2463 __set_size(md
, size
);
2465 dm_table_event_callback(t
, event_callback
, md
);
2468 * The queue hasn't been stopped yet, if the old table type wasn't
2469 * for request-based during suspension. So stop it to prevent
2470 * I/O mapping before resume.
2471 * This must be done before setting the queue restrictions,
2472 * because request-based dm may be run just after the setting.
2474 if (dm_table_request_based(t
))
2477 __bind_mempools(md
, t
);
2479 old_map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
2480 rcu_assign_pointer(md
->map
, t
);
2481 md
->immutable_target_type
= dm_table_get_immutable_target_type(t
);
2483 dm_table_set_restrictions(t
, q
, limits
);
2491 * Returns unbound table for the caller to free.
2493 static struct dm_table
*__unbind(struct mapped_device
*md
)
2495 struct dm_table
*map
= rcu_dereference_protected(md
->map
, 1);
2500 dm_table_event_callback(map
, NULL
, NULL
);
2501 RCU_INIT_POINTER(md
->map
, NULL
);
2508 * Constructor for a new device.
2510 int dm_create(int minor
, struct mapped_device
**result
)
2512 struct mapped_device
*md
;
2514 md
= alloc_dev(minor
);
2525 * Functions to manage md->type.
2526 * All are required to hold md->type_lock.
2528 void dm_lock_md_type(struct mapped_device
*md
)
2530 mutex_lock(&md
->type_lock
);
2533 void dm_unlock_md_type(struct mapped_device
*md
)
2535 mutex_unlock(&md
->type_lock
);
2538 void dm_set_md_type(struct mapped_device
*md
, unsigned type
)
2540 BUG_ON(!mutex_is_locked(&md
->type_lock
));
2544 unsigned dm_get_md_type(struct mapped_device
*md
)
2546 BUG_ON(!mutex_is_locked(&md
->type_lock
));
2550 struct target_type
*dm_get_immutable_target_type(struct mapped_device
*md
)
2552 return md
->immutable_target_type
;
2556 * The queue_limits are only valid as long as you have a reference
2559 struct queue_limits
*dm_get_queue_limits(struct mapped_device
*md
)
2561 BUG_ON(!atomic_read(&md
->holders
));
2562 return &md
->queue
->limits
;
2564 EXPORT_SYMBOL_GPL(dm_get_queue_limits
);
2566 static void init_rq_based_worker_thread(struct mapped_device
*md
)
2568 /* Initialize the request-based DM worker thread */
2569 init_kthread_worker(&md
->kworker
);
2570 md
->kworker_task
= kthread_run(kthread_worker_fn
, &md
->kworker
,
2571 "kdmwork-%s", dm_device_name(md
));
2575 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2577 static int dm_init_request_based_queue(struct mapped_device
*md
)
2579 struct request_queue
*q
= NULL
;
2581 /* Fully initialize the queue */
2582 q
= blk_init_allocated_queue(md
->queue
, dm_request_fn
, NULL
);
2586 /* disable dm_request_fn's merge heuristic by default */
2587 md
->seq_rq_merge_deadline_usecs
= 0;
2590 dm_init_old_md_queue(md
);
2591 blk_queue_softirq_done(md
->queue
, dm_softirq_done
);
2592 blk_queue_prep_rq(md
->queue
, dm_prep_fn
);
2594 init_rq_based_worker_thread(md
);
2596 elv_register_queue(md
->queue
);
2601 static int dm_mq_init_request(void *data
, struct request
*rq
,
2602 unsigned int hctx_idx
, unsigned int request_idx
,
2603 unsigned int numa_node
)
2605 struct mapped_device
*md
= data
;
2606 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
2609 * Must initialize md member of tio, otherwise it won't
2610 * be available in dm_mq_queue_rq.
2617 static int dm_mq_queue_rq(struct blk_mq_hw_ctx
*hctx
,
2618 const struct blk_mq_queue_data
*bd
)
2620 struct request
*rq
= bd
->rq
;
2621 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
2622 struct mapped_device
*md
= tio
->md
;
2624 struct dm_table
*map
= dm_get_live_table(md
, &srcu_idx
);
2625 struct dm_target
*ti
;
2628 /* always use block 0 to find the target for flushes for now */
2630 if (!(rq
->cmd_flags
& REQ_FLUSH
))
2631 pos
= blk_rq_pos(rq
);
2633 ti
= dm_table_find_target(map
, pos
);
2634 if (!dm_target_is_valid(ti
)) {
2635 dm_put_live_table(md
, srcu_idx
);
2636 DMERR_LIMIT("request attempted access beyond the end of device");
2638 * Must perform setup, that rq_completed() requires,
2639 * before returning BLK_MQ_RQ_QUEUE_ERROR
2641 dm_start_request(md
, rq
);
2642 return BLK_MQ_RQ_QUEUE_ERROR
;
2644 dm_put_live_table(md
, srcu_idx
);
2646 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
2647 return BLK_MQ_RQ_QUEUE_BUSY
;
2649 dm_start_request(md
, rq
);
2651 /* Init tio using md established in .init_request */
2652 init_tio(tio
, rq
, md
);
2655 * Establish tio->ti before queuing work (map_tio_request)
2656 * or making direct call to map_request().
2660 /* Clone the request if underlying devices aren't blk-mq */
2661 if (dm_table_get_type(map
) == DM_TYPE_REQUEST_BASED
) {
2662 /* clone request is allocated at the end of the pdu */
2663 tio
->clone
= (void *)blk_mq_rq_to_pdu(rq
) + sizeof(struct dm_rq_target_io
);
2664 (void) clone_rq(rq
, md
, tio
, GFP_ATOMIC
);
2665 queue_kthread_work(&md
->kworker
, &tio
->work
);
2667 /* Direct call is fine since .queue_rq allows allocations */
2668 if (map_request(tio
, rq
, md
) == DM_MAPIO_REQUEUE
) {
2669 /* Undo dm_start_request() before requeuing */
2670 rq_end_stats(md
, rq
);
2671 rq_completed(md
, rq_data_dir(rq
), false);
2672 return BLK_MQ_RQ_QUEUE_BUSY
;
2676 return BLK_MQ_RQ_QUEUE_OK
;
2679 static struct blk_mq_ops dm_mq_ops
= {
2680 .queue_rq
= dm_mq_queue_rq
,
2681 .map_queue
= blk_mq_map_queue
,
2682 .complete
= dm_softirq_done
,
2683 .init_request
= dm_mq_init_request
,
2686 static int dm_init_request_based_blk_mq_queue(struct mapped_device
*md
)
2688 unsigned md_type
= dm_get_md_type(md
);
2689 struct request_queue
*q
;
2692 memset(&md
->tag_set
, 0, sizeof(md
->tag_set
));
2693 md
->tag_set
.ops
= &dm_mq_ops
;
2694 md
->tag_set
.queue_depth
= BLKDEV_MAX_RQ
;
2695 md
->tag_set
.numa_node
= NUMA_NO_NODE
;
2696 md
->tag_set
.flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_SG_MERGE
;
2697 md
->tag_set
.nr_hw_queues
= 1;
2698 if (md_type
== DM_TYPE_REQUEST_BASED
) {
2699 /* make the memory for non-blk-mq clone part of the pdu */
2700 md
->tag_set
.cmd_size
= sizeof(struct dm_rq_target_io
) + sizeof(struct request
);
2702 md
->tag_set
.cmd_size
= sizeof(struct dm_rq_target_io
);
2703 md
->tag_set
.driver_data
= md
;
2705 err
= blk_mq_alloc_tag_set(&md
->tag_set
);
2709 q
= blk_mq_init_allocated_queue(&md
->tag_set
, md
->queue
);
2715 dm_init_md_queue(md
);
2717 /* backfill 'mq' sysfs registration normally done in blk_register_queue */
2718 blk_mq_register_disk(md
->disk
);
2720 if (md_type
== DM_TYPE_REQUEST_BASED
)
2721 init_rq_based_worker_thread(md
);
2726 blk_mq_free_tag_set(&md
->tag_set
);
2730 static unsigned filter_md_type(unsigned type
, struct mapped_device
*md
)
2732 if (type
== DM_TYPE_BIO_BASED
)
2735 return !md
->use_blk_mq
? DM_TYPE_REQUEST_BASED
: DM_TYPE_MQ_REQUEST_BASED
;
2739 * Setup the DM device's queue based on md's type
2741 int dm_setup_md_queue(struct mapped_device
*md
)
2744 unsigned md_type
= filter_md_type(dm_get_md_type(md
), md
);
2747 case DM_TYPE_REQUEST_BASED
:
2748 r
= dm_init_request_based_queue(md
);
2750 DMWARN("Cannot initialize queue for request-based mapped device");
2754 case DM_TYPE_MQ_REQUEST_BASED
:
2755 r
= dm_init_request_based_blk_mq_queue(md
);
2757 DMWARN("Cannot initialize queue for request-based blk-mq mapped device");
2761 case DM_TYPE_BIO_BASED
:
2762 dm_init_old_md_queue(md
);
2763 blk_queue_make_request(md
->queue
, dm_make_request
);
2770 struct mapped_device
*dm_get_md(dev_t dev
)
2772 struct mapped_device
*md
;
2773 unsigned minor
= MINOR(dev
);
2775 if (MAJOR(dev
) != _major
|| minor
>= (1 << MINORBITS
))
2778 spin_lock(&_minor_lock
);
2780 md
= idr_find(&_minor_idr
, minor
);
2782 if ((md
== MINOR_ALLOCED
||
2783 (MINOR(disk_devt(dm_disk(md
))) != minor
) ||
2784 dm_deleting_md(md
) ||
2785 test_bit(DMF_FREEING
, &md
->flags
))) {
2793 spin_unlock(&_minor_lock
);
2797 EXPORT_SYMBOL_GPL(dm_get_md
);
2799 void *dm_get_mdptr(struct mapped_device
*md
)
2801 return md
->interface_ptr
;
2804 void dm_set_mdptr(struct mapped_device
*md
, void *ptr
)
2806 md
->interface_ptr
= ptr
;
2809 void dm_get(struct mapped_device
*md
)
2811 atomic_inc(&md
->holders
);
2812 BUG_ON(test_bit(DMF_FREEING
, &md
->flags
));
2815 int dm_hold(struct mapped_device
*md
)
2817 spin_lock(&_minor_lock
);
2818 if (test_bit(DMF_FREEING
, &md
->flags
)) {
2819 spin_unlock(&_minor_lock
);
2823 spin_unlock(&_minor_lock
);
2826 EXPORT_SYMBOL_GPL(dm_hold
);
2828 const char *dm_device_name(struct mapped_device
*md
)
2832 EXPORT_SYMBOL_GPL(dm_device_name
);
2834 static void __dm_destroy(struct mapped_device
*md
, bool wait
)
2836 struct dm_table
*map
;
2841 spin_lock(&_minor_lock
);
2842 idr_replace(&_minor_idr
, MINOR_ALLOCED
, MINOR(disk_devt(dm_disk(md
))));
2843 set_bit(DMF_FREEING
, &md
->flags
);
2844 spin_unlock(&_minor_lock
);
2846 if (dm_request_based(md
) && md
->kworker_task
)
2847 flush_kthread_worker(&md
->kworker
);
2850 * Take suspend_lock so that presuspend and postsuspend methods
2851 * do not race with internal suspend.
2853 mutex_lock(&md
->suspend_lock
);
2854 map
= dm_get_live_table(md
, &srcu_idx
);
2855 if (!dm_suspended_md(md
)) {
2856 dm_table_presuspend_targets(map
);
2857 dm_table_postsuspend_targets(map
);
2859 /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
2860 dm_put_live_table(md
, srcu_idx
);
2861 mutex_unlock(&md
->suspend_lock
);
2864 * Rare, but there may be I/O requests still going to complete,
2865 * for example. Wait for all references to disappear.
2866 * No one should increment the reference count of the mapped_device,
2867 * after the mapped_device state becomes DMF_FREEING.
2870 while (atomic_read(&md
->holders
))
2872 else if (atomic_read(&md
->holders
))
2873 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2874 dm_device_name(md
), atomic_read(&md
->holders
));
2877 dm_table_destroy(__unbind(md
));
2881 void dm_destroy(struct mapped_device
*md
)
2883 __dm_destroy(md
, true);
2886 void dm_destroy_immediate(struct mapped_device
*md
)
2888 __dm_destroy(md
, false);
2891 void dm_put(struct mapped_device
*md
)
2893 atomic_dec(&md
->holders
);
2895 EXPORT_SYMBOL_GPL(dm_put
);
2897 static int dm_wait_for_completion(struct mapped_device
*md
, int interruptible
)
2900 DECLARE_WAITQUEUE(wait
, current
);
2902 add_wait_queue(&md
->wait
, &wait
);
2905 set_current_state(interruptible
);
2907 if (!md_in_flight(md
))
2910 if (interruptible
== TASK_INTERRUPTIBLE
&&
2911 signal_pending(current
)) {
2918 set_current_state(TASK_RUNNING
);
2920 remove_wait_queue(&md
->wait
, &wait
);
2926 * Process the deferred bios
2928 static void dm_wq_work(struct work_struct
*work
)
2930 struct mapped_device
*md
= container_of(work
, struct mapped_device
,
2934 struct dm_table
*map
;
2936 map
= dm_get_live_table(md
, &srcu_idx
);
2938 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)) {
2939 spin_lock_irq(&md
->deferred_lock
);
2940 c
= bio_list_pop(&md
->deferred
);
2941 spin_unlock_irq(&md
->deferred_lock
);
2946 if (dm_request_based(md
))
2947 generic_make_request(c
);
2949 __split_and_process_bio(md
, map
, c
);
2952 dm_put_live_table(md
, srcu_idx
);
2955 static void dm_queue_flush(struct mapped_device
*md
)
2957 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
2958 smp_mb__after_atomic();
2959 queue_work(md
->wq
, &md
->work
);
2963 * Swap in a new table, returning the old one for the caller to destroy.
2965 struct dm_table
*dm_swap_table(struct mapped_device
*md
, struct dm_table
*table
)
2967 struct dm_table
*live_map
= NULL
, *map
= ERR_PTR(-EINVAL
);
2968 struct queue_limits limits
;
2971 mutex_lock(&md
->suspend_lock
);
2973 /* device must be suspended */
2974 if (!dm_suspended_md(md
))
2978 * If the new table has no data devices, retain the existing limits.
2979 * This helps multipath with queue_if_no_path if all paths disappear,
2980 * then new I/O is queued based on these limits, and then some paths
2983 if (dm_table_has_no_data_devices(table
)) {
2984 live_map
= dm_get_live_table_fast(md
);
2986 limits
= md
->queue
->limits
;
2987 dm_put_live_table_fast(md
);
2991 r
= dm_calculate_queue_limits(table
, &limits
);
2998 map
= __bind(md
, table
, &limits
);
3001 mutex_unlock(&md
->suspend_lock
);
3006 * Functions to lock and unlock any filesystem running on the
3009 static int lock_fs(struct mapped_device
*md
)
3013 WARN_ON(md
->frozen_sb
);
3015 md
->frozen_sb
= freeze_bdev(md
->bdev
);
3016 if (IS_ERR(md
->frozen_sb
)) {
3017 r
= PTR_ERR(md
->frozen_sb
);
3018 md
->frozen_sb
= NULL
;
3022 set_bit(DMF_FROZEN
, &md
->flags
);
3027 static void unlock_fs(struct mapped_device
*md
)
3029 if (!test_bit(DMF_FROZEN
, &md
->flags
))
3032 thaw_bdev(md
->bdev
, md
->frozen_sb
);
3033 md
->frozen_sb
= NULL
;
3034 clear_bit(DMF_FROZEN
, &md
->flags
);
3038 * If __dm_suspend returns 0, the device is completely quiescent
3039 * now. There is no request-processing activity. All new requests
3040 * are being added to md->deferred list.
3042 * Caller must hold md->suspend_lock
3044 static int __dm_suspend(struct mapped_device
*md
, struct dm_table
*map
,
3045 unsigned suspend_flags
, int interruptible
)
3047 bool do_lockfs
= suspend_flags
& DM_SUSPEND_LOCKFS_FLAG
;
3048 bool noflush
= suspend_flags
& DM_SUSPEND_NOFLUSH_FLAG
;
3052 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
3053 * This flag is cleared before dm_suspend returns.
3056 set_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
3059 * This gets reverted if there's an error later and the targets
3060 * provide the .presuspend_undo hook.
3062 dm_table_presuspend_targets(map
);
3065 * Flush I/O to the device.
3066 * Any I/O submitted after lock_fs() may not be flushed.
3067 * noflush takes precedence over do_lockfs.
3068 * (lock_fs() flushes I/Os and waits for them to complete.)
3070 if (!noflush
&& do_lockfs
) {
3073 dm_table_presuspend_undo_targets(map
);
3079 * Here we must make sure that no processes are submitting requests
3080 * to target drivers i.e. no one may be executing
3081 * __split_and_process_bio. This is called from dm_request and
3084 * To get all processes out of __split_and_process_bio in dm_request,
3085 * we take the write lock. To prevent any process from reentering
3086 * __split_and_process_bio from dm_request and quiesce the thread
3087 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
3088 * flush_workqueue(md->wq).
3090 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
3092 synchronize_srcu(&md
->io_barrier
);
3095 * Stop md->queue before flushing md->wq in case request-based
3096 * dm defers requests to md->wq from md->queue.
3098 if (dm_request_based(md
)) {
3099 stop_queue(md
->queue
);
3100 if (md
->kworker_task
)
3101 flush_kthread_worker(&md
->kworker
);
3104 flush_workqueue(md
->wq
);
3107 * At this point no more requests are entering target request routines.
3108 * We call dm_wait_for_completion to wait for all existing requests
3111 r
= dm_wait_for_completion(md
, interruptible
);
3114 clear_bit(DMF_NOFLUSH_SUSPENDING
, &md
->flags
);
3116 synchronize_srcu(&md
->io_barrier
);
3118 /* were we interrupted ? */
3122 if (dm_request_based(md
))
3123 start_queue(md
->queue
);
3126 dm_table_presuspend_undo_targets(map
);
3127 /* pushback list is already flushed, so skip flush */
3134 * We need to be able to change a mapping table under a mounted
3135 * filesystem. For example we might want to move some data in
3136 * the background. Before the table can be swapped with
3137 * dm_bind_table, dm_suspend must be called to flush any in
3138 * flight bios and ensure that any further io gets deferred.
3141 * Suspend mechanism in request-based dm.
3143 * 1. Flush all I/Os by lock_fs() if needed.
3144 * 2. Stop dispatching any I/O by stopping the request_queue.
3145 * 3. Wait for all in-flight I/Os to be completed or requeued.
3147 * To abort suspend, start the request_queue.
3149 int dm_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
3151 struct dm_table
*map
= NULL
;
3155 mutex_lock_nested(&md
->suspend_lock
, SINGLE_DEPTH_NESTING
);
3157 if (dm_suspended_md(md
)) {
3162 if (dm_suspended_internally_md(md
)) {
3163 /* already internally suspended, wait for internal resume */
3164 mutex_unlock(&md
->suspend_lock
);
3165 r
= wait_on_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
, TASK_INTERRUPTIBLE
);
3171 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3173 r
= __dm_suspend(md
, map
, suspend_flags
, TASK_INTERRUPTIBLE
);
3177 set_bit(DMF_SUSPENDED
, &md
->flags
);
3179 dm_table_postsuspend_targets(map
);
3182 mutex_unlock(&md
->suspend_lock
);
3186 static int __dm_resume(struct mapped_device
*md
, struct dm_table
*map
)
3189 int r
= dm_table_resume_targets(map
);
3197 * Flushing deferred I/Os must be done after targets are resumed
3198 * so that mapping of targets can work correctly.
3199 * Request-based dm is queueing the deferred I/Os in its request_queue.
3201 if (dm_request_based(md
))
3202 start_queue(md
->queue
);
3209 int dm_resume(struct mapped_device
*md
)
3212 struct dm_table
*map
= NULL
;
3215 mutex_lock_nested(&md
->suspend_lock
, SINGLE_DEPTH_NESTING
);
3217 if (!dm_suspended_md(md
))
3220 if (dm_suspended_internally_md(md
)) {
3221 /* already internally suspended, wait for internal resume */
3222 mutex_unlock(&md
->suspend_lock
);
3223 r
= wait_on_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
, TASK_INTERRUPTIBLE
);
3229 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3230 if (!map
|| !dm_table_get_size(map
))
3233 r
= __dm_resume(md
, map
);
3237 clear_bit(DMF_SUSPENDED
, &md
->flags
);
3241 mutex_unlock(&md
->suspend_lock
);
3247 * Internal suspend/resume works like userspace-driven suspend. It waits
3248 * until all bios finish and prevents issuing new bios to the target drivers.
3249 * It may be used only from the kernel.
3252 static void __dm_internal_suspend(struct mapped_device
*md
, unsigned suspend_flags
)
3254 struct dm_table
*map
= NULL
;
3256 if (md
->internal_suspend_count
++)
3257 return; /* nested internal suspend */
3259 if (dm_suspended_md(md
)) {
3260 set_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3261 return; /* nest suspend */
3264 map
= rcu_dereference_protected(md
->map
, lockdep_is_held(&md
->suspend_lock
));
3267 * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
3268 * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
3269 * would require changing .presuspend to return an error -- avoid this
3270 * until there is a need for more elaborate variants of internal suspend.
3272 (void) __dm_suspend(md
, map
, suspend_flags
, TASK_UNINTERRUPTIBLE
);
3274 set_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3276 dm_table_postsuspend_targets(map
);
3279 static void __dm_internal_resume(struct mapped_device
*md
)
3281 BUG_ON(!md
->internal_suspend_count
);
3283 if (--md
->internal_suspend_count
)
3284 return; /* resume from nested internal suspend */
3286 if (dm_suspended_md(md
))
3287 goto done
; /* resume from nested suspend */
3290 * NOTE: existing callers don't need to call dm_table_resume_targets
3291 * (which may fail -- so best to avoid it for now by passing NULL map)
3293 (void) __dm_resume(md
, NULL
);
3296 clear_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3297 smp_mb__after_atomic();
3298 wake_up_bit(&md
->flags
, DMF_SUSPENDED_INTERNALLY
);
3301 void dm_internal_suspend_noflush(struct mapped_device
*md
)
3303 mutex_lock(&md
->suspend_lock
);
3304 __dm_internal_suspend(md
, DM_SUSPEND_NOFLUSH_FLAG
);
3305 mutex_unlock(&md
->suspend_lock
);
3307 EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush
);
3309 void dm_internal_resume(struct mapped_device
*md
)
3311 mutex_lock(&md
->suspend_lock
);
3312 __dm_internal_resume(md
);
3313 mutex_unlock(&md
->suspend_lock
);
3315 EXPORT_SYMBOL_GPL(dm_internal_resume
);
3318 * Fast variants of internal suspend/resume hold md->suspend_lock,
3319 * which prevents interaction with userspace-driven suspend.
3322 void dm_internal_suspend_fast(struct mapped_device
*md
)
3324 mutex_lock(&md
->suspend_lock
);
3325 if (dm_suspended_md(md
) || dm_suspended_internally_md(md
))
3328 set_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
);
3329 synchronize_srcu(&md
->io_barrier
);
3330 flush_workqueue(md
->wq
);
3331 dm_wait_for_completion(md
, TASK_UNINTERRUPTIBLE
);
3333 EXPORT_SYMBOL_GPL(dm_internal_suspend_fast
);
3335 void dm_internal_resume_fast(struct mapped_device
*md
)
3337 if (dm_suspended_md(md
) || dm_suspended_internally_md(md
))
3343 mutex_unlock(&md
->suspend_lock
);
3345 EXPORT_SYMBOL_GPL(dm_internal_resume_fast
);
3347 /*-----------------------------------------------------------------
3348 * Event notification.
3349 *---------------------------------------------------------------*/
3350 int dm_kobject_uevent(struct mapped_device
*md
, enum kobject_action action
,
3353 char udev_cookie
[DM_COOKIE_LENGTH
];
3354 char *envp
[] = { udev_cookie
, NULL
};
3357 return kobject_uevent(&disk_to_dev(md
->disk
)->kobj
, action
);
3359 snprintf(udev_cookie
, DM_COOKIE_LENGTH
, "%s=%u",
3360 DM_COOKIE_ENV_VAR_NAME
, cookie
);
3361 return kobject_uevent_env(&disk_to_dev(md
->disk
)->kobj
,
3366 uint32_t dm_next_uevent_seq(struct mapped_device
*md
)
3368 return atomic_add_return(1, &md
->uevent_seq
);
3371 uint32_t dm_get_event_nr(struct mapped_device
*md
)
3373 return atomic_read(&md
->event_nr
);
3376 int dm_wait_event(struct mapped_device
*md
, int event_nr
)
3378 return wait_event_interruptible(md
->eventq
,
3379 (event_nr
!= atomic_read(&md
->event_nr
)));
3382 void dm_uevent_add(struct mapped_device
*md
, struct list_head
*elist
)
3384 unsigned long flags
;
3386 spin_lock_irqsave(&md
->uevent_lock
, flags
);
3387 list_add(elist
, &md
->uevent_list
);
3388 spin_unlock_irqrestore(&md
->uevent_lock
, flags
);
3392 * The gendisk is only valid as long as you have a reference
3395 struct gendisk
*dm_disk(struct mapped_device
*md
)
3399 EXPORT_SYMBOL_GPL(dm_disk
);
3401 struct kobject
*dm_kobject(struct mapped_device
*md
)
3403 return &md
->kobj_holder
.kobj
;
3406 struct mapped_device
*dm_get_from_kobject(struct kobject
*kobj
)
3408 struct mapped_device
*md
;
3410 md
= container_of(kobj
, struct mapped_device
, kobj_holder
.kobj
);
3412 if (test_bit(DMF_FREEING
, &md
->flags
) ||
3420 int dm_suspended_md(struct mapped_device
*md
)
3422 return test_bit(DMF_SUSPENDED
, &md
->flags
);
3425 int dm_suspended_internally_md(struct mapped_device
*md
)
3427 return test_bit(DMF_SUSPENDED_INTERNALLY
, &md
->flags
);
3430 int dm_test_deferred_remove_flag(struct mapped_device
*md
)
3432 return test_bit(DMF_DEFERRED_REMOVE
, &md
->flags
);
3435 int dm_suspended(struct dm_target
*ti
)
3437 return dm_suspended_md(dm_table_get_md(ti
->table
));
3439 EXPORT_SYMBOL_GPL(dm_suspended
);
3441 int dm_noflush_suspending(struct dm_target
*ti
)
3443 return __noflush_suspending(dm_table_get_md(ti
->table
));
3445 EXPORT_SYMBOL_GPL(dm_noflush_suspending
);
3447 struct dm_md_mempools
*dm_alloc_md_mempools(struct mapped_device
*md
, unsigned type
,
3448 unsigned integrity
, unsigned per_bio_data_size
)
3450 struct dm_md_mempools
*pools
= kzalloc(sizeof(*pools
), GFP_KERNEL
);
3451 struct kmem_cache
*cachep
= NULL
;
3452 unsigned int pool_size
= 0;
3453 unsigned int front_pad
;
3458 type
= filter_md_type(type
, md
);
3461 case DM_TYPE_BIO_BASED
:
3463 pool_size
= dm_get_reserved_bio_based_ios();
3464 front_pad
= roundup(per_bio_data_size
, __alignof__(struct dm_target_io
)) + offsetof(struct dm_target_io
, clone
);
3466 case DM_TYPE_REQUEST_BASED
:
3467 cachep
= _rq_tio_cache
;
3468 pool_size
= dm_get_reserved_rq_based_ios();
3469 pools
->rq_pool
= mempool_create_slab_pool(pool_size
, _rq_cache
);
3470 if (!pools
->rq_pool
)
3472 /* fall through to setup remaining rq-based pools */
3473 case DM_TYPE_MQ_REQUEST_BASED
:
3475 pool_size
= dm_get_reserved_rq_based_ios();
3476 front_pad
= offsetof(struct dm_rq_clone_bio_info
, clone
);
3477 /* per_bio_data_size is not used. See __bind_mempools(). */
3478 WARN_ON(per_bio_data_size
!= 0);
3485 pools
->io_pool
= mempool_create_slab_pool(pool_size
, cachep
);
3486 if (!pools
->io_pool
)
3490 pools
->bs
= bioset_create_nobvec(pool_size
, front_pad
);
3494 if (integrity
&& bioset_integrity_create(pools
->bs
, pool_size
))
3500 dm_free_md_mempools(pools
);
3505 void dm_free_md_mempools(struct dm_md_mempools
*pools
)
3511 mempool_destroy(pools
->io_pool
);
3514 mempool_destroy(pools
->rq_pool
);
3517 bioset_free(pools
->bs
);
3522 static const struct block_device_operations dm_blk_dops
= {
3523 .open
= dm_blk_open
,
3524 .release
= dm_blk_close
,
3525 .ioctl
= dm_blk_ioctl
,
3526 .getgeo
= dm_blk_getgeo
,
3527 .owner
= THIS_MODULE
3533 module_init(dm_init
);
3534 module_exit(dm_exit
);
3536 module_param(major
, uint
, 0);
3537 MODULE_PARM_DESC(major
, "The major number of the device mapper");
3539 module_param(reserved_bio_based_ios
, uint
, S_IRUGO
| S_IWUSR
);
3540 MODULE_PARM_DESC(reserved_bio_based_ios
, "Reserved IOs in bio-based mempools");
3542 module_param(reserved_rq_based_ios
, uint
, S_IRUGO
| S_IWUSR
);
3543 MODULE_PARM_DESC(reserved_rq_based_ios
, "Reserved IOs in request-based mempools");
3545 module_param(use_blk_mq
, bool, S_IRUGO
| S_IWUSR
);
3546 MODULE_PARM_DESC(use_blk_mq
, "Use block multiqueue for request-based DM devices");
3548 MODULE_DESCRIPTION(DM_NAME
" driver");
3549 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3550 MODULE_LICENSE("GPL");