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>
25 #include <trace/events/block.h>
27 #define DM_MSG_PREFIX "core"
31 * ratelimit state to be used in DMXXX_LIMIT().
33 DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
34 DEFAULT_RATELIMIT_INTERVAL,
35 DEFAULT_RATELIMIT_BURST);
36 EXPORT_SYMBOL(dm_ratelimit_state);
40 * Cookies are numeric values sent with CHANGE and REMOVE
41 * uevents while resuming, removing or renaming the device.
43 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
44 #define DM_COOKIE_LENGTH 24
46 static const char *_name = DM_NAME;
48 static unsigned int major = 0;
49 static unsigned int _major = 0;
51 static DEFINE_IDR(_minor_idr);
53 static DEFINE_SPINLOCK(_minor_lock);
55 static void do_deferred_remove(struct work_struct *w);
57 static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
59 static struct workqueue_struct *deferred_remove_workqueue;
63 * One of these is allocated per bio.
66 struct mapped_device *md;
70 unsigned long start_time;
71 spinlock_t endio_lock;
72 struct dm_stats_aux stats_aux;
76 * For request-based dm.
77 * One of these is allocated per request.
79 struct dm_rq_target_io {
80 struct mapped_device *md;
82 struct request *orig, *clone;
83 struct kthread_work work;
89 * For request-based dm - the bio clones we allocate are embedded in these
92 * We allocate these with bio_alloc_bioset, using the front_pad parameter when
93 * the bioset is created - this means the bio has to come at the end of the
96 struct dm_rq_clone_bio_info {
98 struct dm_rq_target_io *tio;
102 union map_info *dm_get_rq_mapinfo(struct request *rq)
104 if (rq && rq->end_io_data)
105 return &((struct dm_rq_target_io *)rq->end_io_data)->info;
108 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
110 #define MINOR_ALLOCED ((void *)-1)
113 * Bits for the md->flags field.
115 #define DMF_BLOCK_IO_FOR_SUSPEND 0
116 #define DMF_SUSPENDED 1
118 #define DMF_FREEING 3
119 #define DMF_DELETING 4
120 #define DMF_NOFLUSH_SUSPENDING 5
121 #define DMF_MERGE_IS_OPTIONAL 6
122 #define DMF_DEFERRED_REMOVE 7
123 #define DMF_SUSPENDED_INTERNALLY 8
126 * A dummy definition to make RCU happy.
127 * struct dm_table should never be dereferenced in this file.
134 * Work processed by per-device workqueue.
136 struct mapped_device {
137 struct srcu_struct io_barrier;
138 struct mutex suspend_lock;
143 * The current mapping.
144 * Use dm_get_live_table{_fast} or take suspend_lock for
147 struct dm_table __rcu *map;
149 struct list_head table_devices;
150 struct mutex table_devices_lock;
154 struct request_queue *queue;
156 /* Protect queue and type against concurrent access. */
157 struct mutex type_lock;
159 struct target_type *immutable_target_type;
161 struct gendisk *disk;
167 * A list of ios that arrived while we were suspended.
170 wait_queue_head_t wait;
171 struct work_struct work;
172 struct bio_list deferred;
173 spinlock_t deferred_lock;
176 * Processing queue (flush)
178 struct workqueue_struct *wq;
181 * io objects are allocated from here.
192 wait_queue_head_t eventq;
194 struct list_head uevent_list;
195 spinlock_t uevent_lock; /* Protect access to uevent_list */
198 * freeze/thaw support require holding onto a super block
200 struct super_block *frozen_sb;
201 struct block_device *bdev;
203 /* forced geometry settings */
204 struct hd_geometry geometry;
206 /* kobject and completion */
207 struct dm_kobject_holder kobj_holder;
209 /* zero-length flush that will be cloned and submitted to targets */
210 struct bio flush_bio;
212 /* the number of internal suspends */
213 unsigned internal_suspend_count;
215 struct dm_stats stats;
217 struct kthread_worker kworker;
218 struct task_struct *kworker_task;
222 * For mempools pre-allocation at the table loading time.
224 struct dm_md_mempools {
230 struct table_device {
231 struct list_head list;
233 struct dm_dev dm_dev;
236 #define RESERVED_BIO_BASED_IOS 16
237 #define RESERVED_REQUEST_BASED_IOS 256
238 #define RESERVED_MAX_IOS 1024
239 static struct kmem_cache *_io_cache;
240 static struct kmem_cache *_rq_tio_cache;
241 static struct kmem_cache *_rq_cache;
244 * Bio-based DM's mempools' reserved IOs set by the user.
246 static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
249 * Request-based DM's mempools' reserved IOs set by the user.
251 static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
253 static unsigned __dm_get_module_param(unsigned *module_param,
254 unsigned def, unsigned max)
256 unsigned param = ACCESS_ONCE(*module_param);
257 unsigned modified_param = 0;
260 modified_param = def;
261 else if (param > max)
262 modified_param = max;
264 if (modified_param) {
265 (void)cmpxchg(module_param, param, modified_param);
266 param = modified_param;
272 unsigned dm_get_reserved_bio_based_ios(void)
274 return __dm_get_module_param(&reserved_bio_based_ios,
275 RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);
277 EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
279 unsigned dm_get_reserved_rq_based_ios(void)
281 return __dm_get_module_param(&reserved_rq_based_ios,
282 RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS);
284 EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
286 static int __init local_init(void)
290 /* allocate a slab for the dm_ios */
291 _io_cache = KMEM_CACHE(dm_io, 0);
295 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
297 goto out_free_io_cache;
299 _rq_cache = kmem_cache_create("dm_clone_request", sizeof(struct request),
300 __alignof__(struct request), 0, NULL);
302 goto out_free_rq_tio_cache;
304 r = dm_uevent_init();
306 goto out_free_rq_cache;
308 deferred_remove_workqueue = alloc_workqueue("kdmremove", WQ_UNBOUND, 1);
309 if (!deferred_remove_workqueue) {
311 goto out_uevent_exit;
315 r = register_blkdev(_major, _name);
317 goto out_free_workqueue;
325 destroy_workqueue(deferred_remove_workqueue);
329 kmem_cache_destroy(_rq_cache);
330 out_free_rq_tio_cache:
331 kmem_cache_destroy(_rq_tio_cache);
333 kmem_cache_destroy(_io_cache);
338 static void local_exit(void)
340 flush_scheduled_work();
341 destroy_workqueue(deferred_remove_workqueue);
343 kmem_cache_destroy(_rq_cache);
344 kmem_cache_destroy(_rq_tio_cache);
345 kmem_cache_destroy(_io_cache);
346 unregister_blkdev(_major, _name);
351 DMINFO("cleaned up");
354 static int (*_inits[])(void) __initdata = {
365 static void (*_exits[])(void) = {
376 static int __init dm_init(void)
378 const int count = ARRAY_SIZE(_inits);
382 for (i = 0; i < count; i++) {
397 static void __exit dm_exit(void)
399 int i = ARRAY_SIZE(_exits);
405 * Should be empty by this point.
407 idr_destroy(&_minor_idr);
411 * Block device functions
413 int dm_deleting_md(struct mapped_device *md)
415 return test_bit(DMF_DELETING, &md->flags);
418 static int dm_blk_open(struct block_device *bdev, fmode_t mode)
420 struct mapped_device *md;
422 spin_lock(&_minor_lock);
424 md = bdev->bd_disk->private_data;
428 if (test_bit(DMF_FREEING, &md->flags) ||
429 dm_deleting_md(md)) {
435 atomic_inc(&md->open_count);
437 spin_unlock(&_minor_lock);
439 return md ? 0 : -ENXIO;
442 static void dm_blk_close(struct gendisk *disk, fmode_t mode)
444 struct mapped_device *md;
446 spin_lock(&_minor_lock);
448 md = disk->private_data;
452 if (atomic_dec_and_test(&md->open_count) &&
453 (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
454 queue_work(deferred_remove_workqueue, &deferred_remove_work);
458 spin_unlock(&_minor_lock);
461 int dm_open_count(struct mapped_device *md)
463 return atomic_read(&md->open_count);
467 * Guarantees nothing is using the device before it's deleted.
469 int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
473 spin_lock(&_minor_lock);
475 if (dm_open_count(md)) {
478 set_bit(DMF_DEFERRED_REMOVE, &md->flags);
479 } else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
482 set_bit(DMF_DELETING, &md->flags);
484 spin_unlock(&_minor_lock);
489 int dm_cancel_deferred_remove(struct mapped_device *md)
493 spin_lock(&_minor_lock);
495 if (test_bit(DMF_DELETING, &md->flags))
498 clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
500 spin_unlock(&_minor_lock);
505 static void do_deferred_remove(struct work_struct *w)
507 dm_deferred_remove();
510 sector_t dm_get_size(struct mapped_device *md)
512 return get_capacity(md->disk);
515 struct request_queue *dm_get_md_queue(struct mapped_device *md)
520 struct dm_stats *dm_get_stats(struct mapped_device *md)
525 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
527 struct mapped_device *md = bdev->bd_disk->private_data;
529 return dm_get_geometry(md, geo);
532 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
533 unsigned int cmd, unsigned long arg)
535 struct mapped_device *md = bdev->bd_disk->private_data;
537 struct dm_table *map;
538 struct dm_target *tgt;
542 map = dm_get_live_table(md, &srcu_idx);
544 if (!map || !dm_table_get_size(map))
547 /* We only support devices that have a single target */
548 if (dm_table_get_num_targets(map) != 1)
551 tgt = dm_table_get_target(map, 0);
552 if (!tgt->type->ioctl)
555 if (dm_suspended_md(md)) {
560 r = tgt->type->ioctl(tgt, cmd, arg);
563 dm_put_live_table(md, srcu_idx);
565 if (r == -ENOTCONN) {
573 static struct dm_io *alloc_io(struct mapped_device *md)
575 return mempool_alloc(md->io_pool, GFP_NOIO);
578 static void free_io(struct mapped_device *md, struct dm_io *io)
580 mempool_free(io, md->io_pool);
583 static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
585 bio_put(&tio->clone);
588 static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
591 return mempool_alloc(md->io_pool, gfp_mask);
594 static void free_rq_tio(struct dm_rq_target_io *tio)
596 mempool_free(tio, tio->md->io_pool);
599 static struct request *alloc_clone_request(struct mapped_device *md,
602 return mempool_alloc(md->rq_pool, gfp_mask);
605 static void free_clone_request(struct mapped_device *md, struct request *rq)
607 mempool_free(rq, md->rq_pool);
610 static int md_in_flight(struct mapped_device *md)
612 return atomic_read(&md->pending[READ]) +
613 atomic_read(&md->pending[WRITE]);
616 static void start_io_acct(struct dm_io *io)
618 struct mapped_device *md = io->md;
619 struct bio *bio = io->bio;
621 int rw = bio_data_dir(bio);
623 io->start_time = jiffies;
625 cpu = part_stat_lock();
626 part_round_stats(cpu, &dm_disk(md)->part0);
628 atomic_set(&dm_disk(md)->part0.in_flight[rw],
629 atomic_inc_return(&md->pending[rw]));
631 if (unlikely(dm_stats_used(&md->stats)))
632 dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
633 bio_sectors(bio), false, 0, &io->stats_aux);
636 static void end_io_acct(struct dm_io *io)
638 struct mapped_device *md = io->md;
639 struct bio *bio = io->bio;
640 unsigned long duration = jiffies - io->start_time;
642 int rw = bio_data_dir(bio);
644 generic_end_io_acct(rw, &dm_disk(md)->part0, io->start_time);
646 if (unlikely(dm_stats_used(&md->stats)))
647 dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
648 bio_sectors(bio), true, duration, &io->stats_aux);
651 * After this is decremented the bio must not be touched if it is
654 pending = atomic_dec_return(&md->pending[rw]);
655 atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
656 pending += atomic_read(&md->pending[rw^0x1]);
658 /* nudge anyone waiting on suspend queue */
664 * Add the bio to the list of deferred io.
666 static void queue_io(struct mapped_device *md, struct bio *bio)
670 spin_lock_irqsave(&md->deferred_lock, flags);
671 bio_list_add(&md->deferred, bio);
672 spin_unlock_irqrestore(&md->deferred_lock, flags);
673 queue_work(md->wq, &md->work);
677 * Everyone (including functions in this file), should use this
678 * function to access the md->map field, and make sure they call
679 * dm_put_live_table() when finished.
681 struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx) __acquires(md->io_barrier)
683 *srcu_idx = srcu_read_lock(&md->io_barrier);
685 return srcu_dereference(md->map, &md->io_barrier);
688 void dm_put_live_table(struct mapped_device *md, int srcu_idx) __releases(md->io_barrier)
690 srcu_read_unlock(&md->io_barrier, srcu_idx);
693 void dm_sync_table(struct mapped_device *md)
695 synchronize_srcu(&md->io_barrier);
696 synchronize_rcu_expedited();
700 * A fast alternative to dm_get_live_table/dm_put_live_table.
701 * The caller must not block between these two functions.
703 static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
706 return rcu_dereference(md->map);
709 static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
715 * Open a table device so we can use it as a map destination.
717 static int open_table_device(struct table_device *td, dev_t dev,
718 struct mapped_device *md)
720 static char *_claim_ptr = "I belong to device-mapper";
721 struct block_device *bdev;
725 BUG_ON(td->dm_dev.bdev);
727 bdev = blkdev_get_by_dev(dev, td->dm_dev.mode | FMODE_EXCL, _claim_ptr);
729 return PTR_ERR(bdev);
731 r = bd_link_disk_holder(bdev, dm_disk(md));
733 blkdev_put(bdev, td->dm_dev.mode | FMODE_EXCL);
737 td->dm_dev.bdev = bdev;
742 * Close a table device that we've been using.
744 static void close_table_device(struct table_device *td, struct mapped_device *md)
746 if (!td->dm_dev.bdev)
749 bd_unlink_disk_holder(td->dm_dev.bdev, dm_disk(md));
750 blkdev_put(td->dm_dev.bdev, td->dm_dev.mode | FMODE_EXCL);
751 td->dm_dev.bdev = NULL;
754 static struct table_device *find_table_device(struct list_head *l, dev_t dev,
756 struct table_device *td;
758 list_for_each_entry(td, l, list)
759 if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
765 int dm_get_table_device(struct mapped_device *md, dev_t dev, fmode_t mode,
766 struct dm_dev **result) {
768 struct table_device *td;
770 mutex_lock(&md->table_devices_lock);
771 td = find_table_device(&md->table_devices, dev, mode);
773 td = kmalloc(sizeof(*td), GFP_KERNEL);
775 mutex_unlock(&md->table_devices_lock);
779 td->dm_dev.mode = mode;
780 td->dm_dev.bdev = NULL;
782 if ((r = open_table_device(td, dev, md))) {
783 mutex_unlock(&md->table_devices_lock);
788 format_dev_t(td->dm_dev.name, dev);
790 atomic_set(&td->count, 0);
791 list_add(&td->list, &md->table_devices);
793 atomic_inc(&td->count);
794 mutex_unlock(&md->table_devices_lock);
796 *result = &td->dm_dev;
799 EXPORT_SYMBOL_GPL(dm_get_table_device);
801 void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
803 struct table_device *td = container_of(d, struct table_device, dm_dev);
805 mutex_lock(&md->table_devices_lock);
806 if (atomic_dec_and_test(&td->count)) {
807 close_table_device(td, md);
811 mutex_unlock(&md->table_devices_lock);
813 EXPORT_SYMBOL(dm_put_table_device);
815 static void free_table_devices(struct list_head *devices)
817 struct list_head *tmp, *next;
819 list_for_each_safe(tmp, next, devices) {
820 struct table_device *td = list_entry(tmp, struct table_device, list);
822 DMWARN("dm_destroy: %s still exists with %d references",
823 td->dm_dev.name, atomic_read(&td->count));
829 * Get the geometry associated with a dm device
831 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
839 * Set the geometry of a device.
841 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
843 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
845 if (geo->start > sz) {
846 DMWARN("Start sector is beyond the geometry limits.");
855 /*-----------------------------------------------------------------
857 * A more elegant soln is in the works that uses the queue
858 * merge fn, unfortunately there are a couple of changes to
859 * the block layer that I want to make for this. So in the
860 * interests of getting something for people to use I give
861 * you this clearly demarcated crap.
862 *---------------------------------------------------------------*/
864 static int __noflush_suspending(struct mapped_device *md)
866 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
870 * Decrements the number of outstanding ios that a bio has been
871 * cloned into, completing the original io if necc.
873 static void dec_pending(struct dm_io *io, int error)
878 struct mapped_device *md = io->md;
880 /* Push-back supersedes any I/O errors */
881 if (unlikely(error)) {
882 spin_lock_irqsave(&io->endio_lock, flags);
883 if (!(io->error > 0 && __noflush_suspending(md)))
885 spin_unlock_irqrestore(&io->endio_lock, flags);
888 if (atomic_dec_and_test(&io->io_count)) {
889 if (io->error == DM_ENDIO_REQUEUE) {
891 * Target requested pushing back the I/O.
893 spin_lock_irqsave(&md->deferred_lock, flags);
894 if (__noflush_suspending(md))
895 bio_list_add_head(&md->deferred, io->bio);
897 /* noflush suspend was interrupted. */
899 spin_unlock_irqrestore(&md->deferred_lock, flags);
902 io_error = io->error;
907 if (io_error == DM_ENDIO_REQUEUE)
910 if ((bio->bi_rw & REQ_FLUSH) && bio->bi_iter.bi_size) {
912 * Preflush done for flush with data, reissue
915 bio->bi_rw &= ~REQ_FLUSH;
918 /* done with normal IO or empty flush */
919 trace_block_bio_complete(md->queue, bio, io_error);
920 bio_endio(bio, io_error);
925 static void disable_write_same(struct mapped_device *md)
927 struct queue_limits *limits = dm_get_queue_limits(md);
929 /* device doesn't really support WRITE SAME, disable it */
930 limits->max_write_same_sectors = 0;
933 static void clone_endio(struct bio *bio, int error)
936 struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
937 struct dm_io *io = tio->io;
938 struct mapped_device *md = tio->io->md;
939 dm_endio_fn endio = tio->ti->type->end_io;
941 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
945 r = endio(tio->ti, bio, error);
946 if (r < 0 || r == DM_ENDIO_REQUEUE)
948 * error and requeue request are handled
952 else if (r == DM_ENDIO_INCOMPLETE)
953 /* The target will handle the io */
956 DMWARN("unimplemented target endio return value: %d", r);
961 if (unlikely(r == -EREMOTEIO && (bio->bi_rw & REQ_WRITE_SAME) &&
962 !bdev_get_queue(bio->bi_bdev)->limits.max_write_same_sectors))
963 disable_write_same(md);
966 dec_pending(io, error);
970 * Partial completion handling for request-based dm
972 static void end_clone_bio(struct bio *clone, int error)
974 struct dm_rq_clone_bio_info *info =
975 container_of(clone, struct dm_rq_clone_bio_info, clone);
976 struct dm_rq_target_io *tio = info->tio;
977 struct bio *bio = info->orig;
978 unsigned int nr_bytes = info->orig->bi_iter.bi_size;
984 * An error has already been detected on the request.
985 * Once error occurred, just let clone->end_io() handle
991 * Don't notice the error to the upper layer yet.
992 * The error handling decision is made by the target driver,
993 * when the request is completed.
1000 * I/O for the bio successfully completed.
1001 * Notice the data completion to the upper layer.
1005 * bios are processed from the head of the list.
1006 * So the completing bio should always be rq->bio.
1007 * If it's not, something wrong is happening.
1009 if (tio->orig->bio != bio)
1010 DMERR("bio completion is going in the middle of the request");
1013 * Update the original request.
1014 * Do not use blk_end_request() here, because it may complete
1015 * the original request before the clone, and break the ordering.
1017 blk_update_request(tio->orig, 0, nr_bytes);
1021 * Don't touch any member of the md after calling this function because
1022 * the md may be freed in dm_put() at the end of this function.
1023 * Or do dm_get() before calling this function and dm_put() later.
1025 static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
1027 int nr_requests_pending;
1029 atomic_dec(&md->pending[rw]);
1031 /* nudge anyone waiting on suspend queue */
1032 nr_requests_pending = md_in_flight(md);
1033 if (!nr_requests_pending)
1037 * Run this off this callpath, as drivers could invoke end_io while
1038 * inside their request_fn (and holding the queue lock). Calling
1039 * back into ->request_fn() could deadlock attempting to grab the
1043 if (!nr_requests_pending ||
1044 (nr_requests_pending >= md->queue->nr_congestion_on))
1045 blk_run_queue_async(md->queue);
1049 * dm_put() must be at the end of this function. See the comment above
1054 static void free_rq_clone(struct request *clone)
1056 struct dm_rq_target_io *tio = clone->end_io_data;
1058 blk_rq_unprep_clone(clone);
1059 if (clone->q && clone->q->mq_ops)
1060 tio->ti->type->release_clone_rq(clone);
1062 free_clone_request(tio->md, clone);
1067 * Complete the clone and the original request.
1068 * Must be called without clone's queue lock held,
1069 * see end_clone_request() for more details.
1071 static void dm_end_request(struct request *clone, int error)
1073 int rw = rq_data_dir(clone);
1074 struct dm_rq_target_io *tio = clone->end_io_data;
1075 struct mapped_device *md = tio->md;
1076 struct request *rq = tio->orig;
1078 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
1079 rq->errors = clone->errors;
1080 rq->resid_len = clone->resid_len;
1084 * We are using the sense buffer of the original
1086 * So setting the length of the sense data is enough.
1088 rq->sense_len = clone->sense_len;
1091 free_rq_clone(clone);
1092 blk_end_request_all(rq, error);
1093 rq_completed(md, rw, true);
1096 static void dm_unprep_request(struct request *rq)
1098 struct dm_rq_target_io *tio = rq->special;
1099 struct request *clone = tio->clone;
1102 rq->cmd_flags &= ~REQ_DONTPREP;
1105 free_rq_clone(clone);
1109 * Requeue the original request of a clone.
1111 static void dm_requeue_unmapped_original_request(struct mapped_device *md,
1114 int rw = rq_data_dir(rq);
1115 struct request_queue *q = rq->q;
1116 unsigned long flags;
1118 dm_unprep_request(rq);
1120 spin_lock_irqsave(q->queue_lock, flags);
1121 blk_requeue_request(q, rq);
1122 spin_unlock_irqrestore(q->queue_lock, flags);
1124 rq_completed(md, rw, false);
1127 static void dm_requeue_unmapped_request(struct request *clone)
1129 struct dm_rq_target_io *tio = clone->end_io_data;
1131 dm_requeue_unmapped_original_request(tio->md, tio->orig);
1134 static void __stop_queue(struct request_queue *q)
1139 static void stop_queue(struct request_queue *q)
1141 unsigned long flags;
1143 spin_lock_irqsave(q->queue_lock, flags);
1145 spin_unlock_irqrestore(q->queue_lock, flags);
1148 static void __start_queue(struct request_queue *q)
1150 if (blk_queue_stopped(q))
1154 static void start_queue(struct request_queue *q)
1156 unsigned long flags;
1158 spin_lock_irqsave(q->queue_lock, flags);
1160 spin_unlock_irqrestore(q->queue_lock, flags);
1163 static void dm_done(struct request *clone, int error, bool mapped)
1166 struct dm_rq_target_io *tio = clone->end_io_data;
1167 dm_request_endio_fn rq_end_io = NULL;
1170 rq_end_io = tio->ti->type->rq_end_io;
1172 if (mapped && rq_end_io)
1173 r = rq_end_io(tio->ti, clone, error, &tio->info);
1176 if (unlikely(r == -EREMOTEIO && (clone->cmd_flags & REQ_WRITE_SAME) &&
1177 !clone->q->limits.max_write_same_sectors))
1178 disable_write_same(tio->md);
1181 /* The target wants to complete the I/O */
1182 dm_end_request(clone, r);
1183 else if (r == DM_ENDIO_INCOMPLETE)
1184 /* The target will handle the I/O */
1186 else if (r == DM_ENDIO_REQUEUE)
1187 /* The target wants to requeue the I/O */
1188 dm_requeue_unmapped_request(clone);
1190 DMWARN("unimplemented target endio return value: %d", r);
1196 * Request completion handler for request-based dm
1198 static void dm_softirq_done(struct request *rq)
1201 struct dm_rq_target_io *tio = rq->special;
1202 struct request *clone = tio->clone;
1205 blk_end_request_all(rq, tio->error);
1206 rq_completed(tio->md, rq_data_dir(rq), false);
1211 if (rq->cmd_flags & REQ_FAILED)
1214 dm_done(clone, tio->error, mapped);
1218 * Complete the clone and the original request with the error status
1219 * through softirq context.
1221 static void dm_complete_request(struct request *rq, int error)
1223 struct dm_rq_target_io *tio = rq->special;
1226 blk_complete_request(rq);
1230 * Complete the not-mapped clone and the original request with the error status
1231 * through softirq context.
1232 * Target's rq_end_io() function isn't called.
1233 * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
1235 static void dm_kill_unmapped_request(struct request *rq, int error)
1237 rq->cmd_flags |= REQ_FAILED;
1238 dm_complete_request(rq, error);
1242 * Called with the clone's queue lock held
1244 static void end_clone_request(struct request *clone, int error)
1246 struct dm_rq_target_io *tio = clone->end_io_data;
1248 if (!clone->q->mq_ops) {
1250 * For just cleaning up the information of the queue in which
1251 * the clone was dispatched.
1252 * The clone is *NOT* freed actually here because it is alloced
1253 * from dm own mempool (REQ_ALLOCED isn't set).
1255 __blk_put_request(clone->q, clone);
1259 * Actual request completion is done in a softirq context which doesn't
1260 * hold the clone's queue lock. Otherwise, deadlock could occur because:
1261 * - another request may be submitted by the upper level driver
1262 * of the stacking during the completion
1263 * - the submission which requires queue lock may be done
1264 * against this clone's queue
1266 dm_complete_request(tio->orig, error);
1270 * Return maximum size of I/O possible at the supplied sector up to the current
1273 static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
1275 sector_t target_offset = dm_target_offset(ti, sector);
1277 return ti->len - target_offset;
1280 static sector_t max_io_len(sector_t sector, struct dm_target *ti)
1282 sector_t len = max_io_len_target_boundary(sector, ti);
1283 sector_t offset, max_len;
1286 * Does the target need to split even further?
1288 if (ti->max_io_len) {
1289 offset = dm_target_offset(ti, sector);
1290 if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
1291 max_len = sector_div(offset, ti->max_io_len);
1293 max_len = offset & (ti->max_io_len - 1);
1294 max_len = ti->max_io_len - max_len;
1303 int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
1305 if (len > UINT_MAX) {
1306 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
1307 (unsigned long long)len, UINT_MAX);
1308 ti->error = "Maximum size of target IO is too large";
1312 ti->max_io_len = (uint32_t) len;
1316 EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
1319 * A target may call dm_accept_partial_bio only from the map routine. It is
1320 * allowed for all bio types except REQ_FLUSH.
1322 * dm_accept_partial_bio informs the dm that the target only wants to process
1323 * additional n_sectors sectors of the bio and the rest of the data should be
1324 * sent in a next bio.
1326 * A diagram that explains the arithmetics:
1327 * +--------------------+---------------+-------+
1329 * +--------------------+---------------+-------+
1331 * <-------------- *tio->len_ptr --------------->
1332 * <------- bi_size ------->
1335 * Region 1 was already iterated over with bio_advance or similar function.
1336 * (it may be empty if the target doesn't use bio_advance)
1337 * Region 2 is the remaining bio size that the target wants to process.
1338 * (it may be empty if region 1 is non-empty, although there is no reason
1340 * The target requires that region 3 is to be sent in the next bio.
1342 * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
1343 * the partially processed part (the sum of regions 1+2) must be the same for all
1344 * copies of the bio.
1346 void dm_accept_partial_bio(struct bio *bio, unsigned n_sectors)
1348 struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
1349 unsigned bi_size = bio->bi_iter.bi_size >> SECTOR_SHIFT;
1350 BUG_ON(bio->bi_rw & REQ_FLUSH);
1351 BUG_ON(bi_size > *tio->len_ptr);
1352 BUG_ON(n_sectors > bi_size);
1353 *tio->len_ptr -= bi_size - n_sectors;
1354 bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
1356 EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
1358 static void __map_bio(struct dm_target_io *tio)
1362 struct mapped_device *md;
1363 struct bio *clone = &tio->clone;
1364 struct dm_target *ti = tio->ti;
1366 clone->bi_end_io = clone_endio;
1369 * Map the clone. If r == 0 we don't need to do
1370 * anything, the target has assumed ownership of
1373 atomic_inc(&tio->io->io_count);
1374 sector = clone->bi_iter.bi_sector;
1375 r = ti->type->map(ti, clone);
1376 if (r == DM_MAPIO_REMAPPED) {
1377 /* the bio has been remapped so dispatch it */
1379 trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
1380 tio->io->bio->bi_bdev->bd_dev, sector);
1382 generic_make_request(clone);
1383 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
1384 /* error the io and bail out, or requeue it if needed */
1386 dec_pending(tio->io, r);
1389 DMWARN("unimplemented target map return value: %d", r);
1395 struct mapped_device *md;
1396 struct dm_table *map;
1400 unsigned sector_count;
1403 static void bio_setup_sector(struct bio *bio, sector_t sector, unsigned len)
1405 bio->bi_iter.bi_sector = sector;
1406 bio->bi_iter.bi_size = to_bytes(len);
1410 * Creates a bio that consists of range of complete bvecs.
1412 static void clone_bio(struct dm_target_io *tio, struct bio *bio,
1413 sector_t sector, unsigned len)
1415 struct bio *clone = &tio->clone;
1417 __bio_clone_fast(clone, bio);
1419 if (bio_integrity(bio))
1420 bio_integrity_clone(clone, bio, GFP_NOIO);
1422 bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
1423 clone->bi_iter.bi_size = to_bytes(len);
1425 if (bio_integrity(bio))
1426 bio_integrity_trim(clone, 0, len);
1429 static struct dm_target_io *alloc_tio(struct clone_info *ci,
1430 struct dm_target *ti,
1431 unsigned target_bio_nr)
1433 struct dm_target_io *tio;
1436 clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
1437 tio = container_of(clone, struct dm_target_io, clone);
1441 tio->target_bio_nr = target_bio_nr;
1446 static void __clone_and_map_simple_bio(struct clone_info *ci,
1447 struct dm_target *ti,
1448 unsigned target_bio_nr, unsigned *len)
1450 struct dm_target_io *tio = alloc_tio(ci, ti, target_bio_nr);
1451 struct bio *clone = &tio->clone;
1455 __bio_clone_fast(clone, ci->bio);
1457 bio_setup_sector(clone, ci->sector, *len);
1462 static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
1463 unsigned num_bios, unsigned *len)
1465 unsigned target_bio_nr;
1467 for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
1468 __clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
1471 static int __send_empty_flush(struct clone_info *ci)
1473 unsigned target_nr = 0;
1474 struct dm_target *ti;
1476 BUG_ON(bio_has_data(ci->bio));
1477 while ((ti = dm_table_get_target(ci->map, target_nr++)))
1478 __send_duplicate_bios(ci, ti, ti->num_flush_bios, NULL);
1483 static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
1484 sector_t sector, unsigned *len)
1486 struct bio *bio = ci->bio;
1487 struct dm_target_io *tio;
1488 unsigned target_bio_nr;
1489 unsigned num_target_bios = 1;
1492 * Does the target want to receive duplicate copies of the bio?
1494 if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
1495 num_target_bios = ti->num_write_bios(ti, bio);
1497 for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
1498 tio = alloc_tio(ci, ti, target_bio_nr);
1500 clone_bio(tio, bio, sector, *len);
1505 typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
1507 static unsigned get_num_discard_bios(struct dm_target *ti)
1509 return ti->num_discard_bios;
1512 static unsigned get_num_write_same_bios(struct dm_target *ti)
1514 return ti->num_write_same_bios;
1517 typedef bool (*is_split_required_fn)(struct dm_target *ti);
1519 static bool is_split_required_for_discard(struct dm_target *ti)
1521 return ti->split_discard_bios;
1524 static int __send_changing_extent_only(struct clone_info *ci,
1525 get_num_bios_fn get_num_bios,
1526 is_split_required_fn is_split_required)
1528 struct dm_target *ti;
1533 ti = dm_table_find_target(ci->map, ci->sector);
1534 if (!dm_target_is_valid(ti))
1538 * Even though the device advertised support for this type of
1539 * request, that does not mean every target supports it, and
1540 * reconfiguration might also have changed that since the
1541 * check was performed.
1543 num_bios = get_num_bios ? get_num_bios(ti) : 0;
1547 if (is_split_required && !is_split_required(ti))
1548 len = min((sector_t)ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
1550 len = min((sector_t)ci->sector_count, max_io_len(ci->sector, ti));
1552 __send_duplicate_bios(ci, ti, num_bios, &len);
1555 } while (ci->sector_count -= len);
1560 static int __send_discard(struct clone_info *ci)
1562 return __send_changing_extent_only(ci, get_num_discard_bios,
1563 is_split_required_for_discard);
1566 static int __send_write_same(struct clone_info *ci)
1568 return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
1572 * Select the correct strategy for processing a non-flush bio.
1574 static int __split_and_process_non_flush(struct clone_info *ci)
1576 struct bio *bio = ci->bio;
1577 struct dm_target *ti;
1580 if (unlikely(bio->bi_rw & REQ_DISCARD))
1581 return __send_discard(ci);
1582 else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
1583 return __send_write_same(ci);
1585 ti = dm_table_find_target(ci->map, ci->sector);
1586 if (!dm_target_is_valid(ti))
1589 len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
1591 __clone_and_map_data_bio(ci, ti, ci->sector, &len);
1594 ci->sector_count -= len;
1600 * Entry point to split a bio into clones and submit them to the targets.
1602 static void __split_and_process_bio(struct mapped_device *md,
1603 struct dm_table *map, struct bio *bio)
1605 struct clone_info ci;
1608 if (unlikely(!map)) {
1615 ci.io = alloc_io(md);
1617 atomic_set(&ci.io->io_count, 1);
1620 spin_lock_init(&ci.io->endio_lock);
1621 ci.sector = bio->bi_iter.bi_sector;
1623 start_io_acct(ci.io);
1625 if (bio->bi_rw & REQ_FLUSH) {
1626 ci.bio = &ci.md->flush_bio;
1627 ci.sector_count = 0;
1628 error = __send_empty_flush(&ci);
1629 /* dec_pending submits any data associated with flush */
1632 ci.sector_count = bio_sectors(bio);
1633 while (ci.sector_count && !error)
1634 error = __split_and_process_non_flush(&ci);
1637 /* drop the extra reference count */
1638 dec_pending(ci.io, error);
1640 /*-----------------------------------------------------------------
1642 *---------------------------------------------------------------*/
1644 static int dm_merge_bvec(struct request_queue *q,
1645 struct bvec_merge_data *bvm,
1646 struct bio_vec *biovec)
1648 struct mapped_device *md = q->queuedata;
1649 struct dm_table *map = dm_get_live_table_fast(md);
1650 struct dm_target *ti;
1651 sector_t max_sectors;
1657 ti = dm_table_find_target(map, bvm->bi_sector);
1658 if (!dm_target_is_valid(ti))
1662 * Find maximum amount of I/O that won't need splitting
1664 max_sectors = min(max_io_len(bvm->bi_sector, ti),
1665 (sector_t) queue_max_sectors(q));
1666 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
1667 if (unlikely(max_size < 0)) /* this shouldn't _ever_ happen */
1671 * merge_bvec_fn() returns number of bytes
1672 * it can accept at this offset
1673 * max is precomputed maximal io size
1675 if (max_size && ti->type->merge)
1676 max_size = ti->type->merge(ti, bvm, biovec, max_size);
1678 * If the target doesn't support merge method and some of the devices
1679 * provided their merge_bvec method (we know this by looking for the
1680 * max_hw_sectors that dm_set_device_limits may set), then we can't
1681 * allow bios with multiple vector entries. So always set max_size
1682 * to 0, and the code below allows just one page.
1684 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
1688 dm_put_live_table_fast(md);
1690 * Always allow an entire first page
1692 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
1693 max_size = biovec->bv_len;
1699 * The request function that just remaps the bio built up by
1702 static void dm_make_request(struct request_queue *q, struct bio *bio)
1704 int rw = bio_data_dir(bio);
1705 struct mapped_device *md = q->queuedata;
1707 struct dm_table *map;
1709 map = dm_get_live_table(md, &srcu_idx);
1711 generic_start_io_acct(rw, bio_sectors(bio), &dm_disk(md)->part0);
1713 /* if we're suspended, we have to queue this io for later */
1714 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
1715 dm_put_live_table(md, srcu_idx);
1717 if (bio_rw(bio) != READA)
1724 __split_and_process_bio(md, map, bio);
1725 dm_put_live_table(md, srcu_idx);
1729 int dm_request_based(struct mapped_device *md)
1731 return blk_queue_stackable(md->queue);
1734 static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
1738 if (blk_queue_io_stat(clone->q))
1739 clone->cmd_flags |= REQ_IO_STAT;
1741 clone->start_time = jiffies;
1742 r = blk_insert_cloned_request(clone->q, clone);
1744 /* must complete clone in terms of original request */
1745 dm_complete_request(rq, r);
1748 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
1751 struct dm_rq_target_io *tio = data;
1752 struct dm_rq_clone_bio_info *info =
1753 container_of(bio, struct dm_rq_clone_bio_info, clone);
1755 info->orig = bio_orig;
1757 bio->bi_end_io = end_clone_bio;
1762 static int setup_clone(struct request *clone, struct request *rq,
1763 struct dm_rq_target_io *tio, gfp_t gfp_mask)
1767 r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask,
1768 dm_rq_bio_constructor, tio);
1772 clone->cmd = rq->cmd;
1773 clone->cmd_len = rq->cmd_len;
1774 clone->sense = rq->sense;
1775 clone->end_io = end_clone_request;
1776 clone->end_io_data = tio;
1783 static struct request *clone_rq(struct request *rq, struct mapped_device *md,
1784 struct dm_rq_target_io *tio, gfp_t gfp_mask)
1786 struct request *clone = alloc_clone_request(md, gfp_mask);
1791 blk_rq_init(NULL, clone);
1792 if (setup_clone(clone, rq, tio, gfp_mask)) {
1794 free_clone_request(md, clone);
1801 static void map_tio_request(struct kthread_work *work);
1803 static struct dm_rq_target_io *prep_tio(struct request *rq,
1804 struct mapped_device *md, gfp_t gfp_mask)
1806 struct dm_rq_target_io *tio;
1808 struct dm_table *table;
1810 tio = alloc_rq_tio(md, gfp_mask);
1819 memset(&tio->info, 0, sizeof(tio->info));
1820 init_kthread_work(&tio->work, map_tio_request);
1822 table = dm_get_live_table(md, &srcu_idx);
1823 if (!dm_table_mq_request_based(table)) {
1824 if (!clone_rq(rq, md, tio, gfp_mask)) {
1825 dm_put_live_table(md, srcu_idx);
1830 dm_put_live_table(md, srcu_idx);
1836 * Called with the queue lock held.
1838 static int dm_prep_fn(struct request_queue *q, struct request *rq)
1840 struct mapped_device *md = q->queuedata;
1841 struct dm_rq_target_io *tio;
1843 if (unlikely(rq->special)) {
1844 DMWARN("Already has something in rq->special.");
1845 return BLKPREP_KILL;
1848 tio = prep_tio(rq, md, GFP_ATOMIC);
1850 return BLKPREP_DEFER;
1853 rq->cmd_flags |= REQ_DONTPREP;
1860 * 0 : the request has been processed
1861 * DM_MAPIO_REQUEUE : the original request needs to be requeued
1862 * < 0 : the request was completed due to failure
1864 static int map_request(struct dm_target *ti, struct request *rq,
1865 struct mapped_device *md)
1868 struct dm_rq_target_io *tio = rq->special;
1869 struct request *clone = NULL;
1873 r = ti->type->map_rq(ti, clone, &tio->info);
1875 r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
1877 /* The target wants to complete the I/O */
1878 dm_kill_unmapped_request(rq, r);
1882 return DM_MAPIO_REQUEUE;
1883 if (setup_clone(clone, rq, tio, GFP_KERNEL)) {
1885 ti->type->release_clone_rq(clone);
1886 return DM_MAPIO_REQUEUE;
1891 case DM_MAPIO_SUBMITTED:
1892 /* The target has taken the I/O to submit by itself later */
1894 case DM_MAPIO_REMAPPED:
1895 /* The target has remapped the I/O so dispatch it */
1896 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
1898 dm_dispatch_clone_request(clone, rq);
1900 case DM_MAPIO_REQUEUE:
1901 /* The target wants to requeue the I/O */
1902 dm_requeue_unmapped_request(clone);
1906 DMWARN("unimplemented target map return value: %d", r);
1910 /* The target wants to complete the I/O */
1911 dm_kill_unmapped_request(rq, r);
1918 static void map_tio_request(struct kthread_work *work)
1920 struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
1921 struct request *rq = tio->orig;
1922 struct mapped_device *md = tio->md;
1924 if (map_request(tio->ti, rq, md) == DM_MAPIO_REQUEUE)
1925 dm_requeue_unmapped_original_request(md, rq);
1928 static void dm_start_request(struct mapped_device *md, struct request *orig)
1930 blk_start_request(orig);
1931 atomic_inc(&md->pending[rq_data_dir(orig)]);
1934 * Hold the md reference here for the in-flight I/O.
1935 * We can't rely on the reference count by device opener,
1936 * because the device may be closed during the request completion
1937 * when all bios are completed.
1938 * See the comment in rq_completed() too.
1944 * q->request_fn for request-based dm.
1945 * Called with the queue lock held.
1947 static void dm_request_fn(struct request_queue *q)
1949 struct mapped_device *md = q->queuedata;
1951 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
1952 struct dm_target *ti;
1954 struct dm_rq_target_io *tio;
1958 * For suspend, check blk_queue_stopped() and increment
1959 * ->pending within a single queue_lock not to increment the
1960 * number of in-flight I/Os after the queue is stopped in
1963 while (!blk_queue_stopped(q)) {
1964 rq = blk_peek_request(q);
1968 /* always use block 0 to find the target for flushes for now */
1970 if (!(rq->cmd_flags & REQ_FLUSH))
1971 pos = blk_rq_pos(rq);
1973 ti = dm_table_find_target(map, pos);
1974 if (!dm_target_is_valid(ti)) {
1976 * Must perform setup, that rq_completed() requires,
1977 * before calling dm_kill_unmapped_request
1979 DMERR_LIMIT("request attempted access beyond the end of device");
1980 dm_start_request(md, rq);
1981 dm_kill_unmapped_request(rq, -EIO);
1985 if (ti->type->busy && ti->type->busy(ti))
1988 dm_start_request(md, rq);
1991 /* Establish tio->ti before queuing work (map_tio_request) */
1993 queue_kthread_work(&md->kworker, &tio->work);
1994 BUG_ON(!irqs_disabled());
2000 blk_delay_queue(q, HZ / 10);
2002 dm_put_live_table(md, srcu_idx);
2005 static int dm_any_congested(void *congested_data, int bdi_bits)
2008 struct mapped_device *md = congested_data;
2009 struct dm_table *map;
2011 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2012 map = dm_get_live_table_fast(md);
2015 * Request-based dm cares about only own queue for
2016 * the query about congestion status of request_queue
2018 if (dm_request_based(md))
2019 r = md->queue->backing_dev_info.state &
2022 r = dm_table_any_congested(map, bdi_bits);
2024 dm_put_live_table_fast(md);
2030 /*-----------------------------------------------------------------
2031 * An IDR is used to keep track of allocated minor numbers.
2032 *---------------------------------------------------------------*/
2033 static void free_minor(int minor)
2035 spin_lock(&_minor_lock);
2036 idr_remove(&_minor_idr, minor);
2037 spin_unlock(&_minor_lock);
2041 * See if the device with a specific minor # is free.
2043 static int specific_minor(int minor)
2047 if (minor >= (1 << MINORBITS))
2050 idr_preload(GFP_KERNEL);
2051 spin_lock(&_minor_lock);
2053 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
2055 spin_unlock(&_minor_lock);
2058 return r == -ENOSPC ? -EBUSY : r;
2062 static int next_free_minor(int *minor)
2066 idr_preload(GFP_KERNEL);
2067 spin_lock(&_minor_lock);
2069 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
2071 spin_unlock(&_minor_lock);
2079 static const struct block_device_operations dm_blk_dops;
2081 static void dm_wq_work(struct work_struct *work);
2083 static void dm_init_md_queue(struct mapped_device *md)
2086 * Request-based dm devices cannot be stacked on top of bio-based dm
2087 * devices. The type of this dm device has not been decided yet.
2088 * The type is decided at the first table loading time.
2089 * To prevent problematic device stacking, clear the queue flag
2090 * for request stacking support until then.
2092 * This queue is new, so no concurrency on the queue_flags.
2094 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
2096 md->queue->queuedata = md;
2097 md->queue->backing_dev_info.congested_fn = dm_any_congested;
2098 md->queue->backing_dev_info.congested_data = md;
2100 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
2104 * Allocate and initialise a blank device with a given minor.
2106 static struct mapped_device *alloc_dev(int minor)
2109 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
2113 DMWARN("unable to allocate device, out of memory.");
2117 if (!try_module_get(THIS_MODULE))
2118 goto bad_module_get;
2120 /* get a minor number for the dev */
2121 if (minor == DM_ANY_MINOR)
2122 r = next_free_minor(&minor);
2124 r = specific_minor(minor);
2128 r = init_srcu_struct(&md->io_barrier);
2130 goto bad_io_barrier;
2132 md->type = DM_TYPE_NONE;
2133 mutex_init(&md->suspend_lock);
2134 mutex_init(&md->type_lock);
2135 mutex_init(&md->table_devices_lock);
2136 spin_lock_init(&md->deferred_lock);
2137 atomic_set(&md->holders, 1);
2138 atomic_set(&md->open_count, 0);
2139 atomic_set(&md->event_nr, 0);
2140 atomic_set(&md->uevent_seq, 0);
2141 INIT_LIST_HEAD(&md->uevent_list);
2142 INIT_LIST_HEAD(&md->table_devices);
2143 spin_lock_init(&md->uevent_lock);
2145 md->queue = blk_alloc_queue(GFP_KERNEL);
2149 dm_init_md_queue(md);
2151 md->disk = alloc_disk(1);
2155 atomic_set(&md->pending[0], 0);
2156 atomic_set(&md->pending[1], 0);
2157 init_waitqueue_head(&md->wait);
2158 INIT_WORK(&md->work, dm_wq_work);
2159 init_waitqueue_head(&md->eventq);
2160 init_completion(&md->kobj_holder.completion);
2161 md->kworker_task = NULL;
2163 md->disk->major = _major;
2164 md->disk->first_minor = minor;
2165 md->disk->fops = &dm_blk_dops;
2166 md->disk->queue = md->queue;
2167 md->disk->private_data = md;
2168 sprintf(md->disk->disk_name, "dm-%d", minor);
2170 format_dev_t(md->name, MKDEV(_major, minor));
2172 md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
2176 md->bdev = bdget_disk(md->disk, 0);
2180 bio_init(&md->flush_bio);
2181 md->flush_bio.bi_bdev = md->bdev;
2182 md->flush_bio.bi_rw = WRITE_FLUSH;
2184 dm_stats_init(&md->stats);
2186 /* Populate the mapping, nobody knows we exist yet */
2187 spin_lock(&_minor_lock);
2188 old_md = idr_replace(&_minor_idr, md, minor);
2189 spin_unlock(&_minor_lock);
2191 BUG_ON(old_md != MINOR_ALLOCED);
2196 destroy_workqueue(md->wq);
2198 del_gendisk(md->disk);
2201 blk_cleanup_queue(md->queue);
2203 cleanup_srcu_struct(&md->io_barrier);
2207 module_put(THIS_MODULE);
2213 static void unlock_fs(struct mapped_device *md);
2215 static void free_dev(struct mapped_device *md)
2217 int minor = MINOR(disk_devt(md->disk));
2220 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);
2232 free_table_devices(&md->table_devices);
2233 dm_stats_cleanup(&md->stats);
2235 spin_lock(&_minor_lock);
2236 md->disk->private_data = NULL;
2237 spin_unlock(&_minor_lock);
2238 if (blk_get_integrity(md->disk))
2239 blk_integrity_unregister(md->disk);
2240 del_gendisk(md->disk);
2242 blk_cleanup_queue(md->queue);
2246 module_put(THIS_MODULE);
2250 static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
2252 struct dm_md_mempools *p = dm_table_get_md_mempools(t);
2254 if (md->io_pool && md->bs) {
2255 /* The md already has necessary mempools. */
2256 if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
2258 * Reload bioset because front_pad may have changed
2259 * because a different table was loaded.
2261 bioset_free(md->bs);
2266 * There's no need to reload with request-based dm
2267 * because the size of front_pad doesn't change.
2268 * Note for future: If you are to reload bioset,
2269 * prep-ed requests in the queue may refer
2270 * to bio from the old bioset, so you must walk
2271 * through the queue to unprep.
2276 BUG_ON(!p || md->io_pool || md->rq_pool || md->bs);
2278 md->io_pool = p->io_pool;
2280 md->rq_pool = p->rq_pool;
2286 /* mempool bind completed, now no need any mempools in the table */
2287 dm_table_free_md_mempools(t);
2291 * Bind a table to the device.
2293 static void event_callback(void *context)
2295 unsigned long flags;
2297 struct mapped_device *md = (struct mapped_device *) context;
2299 spin_lock_irqsave(&md->uevent_lock, flags);
2300 list_splice_init(&md->uevent_list, &uevents);
2301 spin_unlock_irqrestore(&md->uevent_lock, flags);
2303 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
2305 atomic_inc(&md->event_nr);
2306 wake_up(&md->eventq);
2310 * Protected by md->suspend_lock obtained by dm_swap_table().
2312 static void __set_size(struct mapped_device *md, sector_t size)
2314 set_capacity(md->disk, size);
2316 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
2320 * Return 1 if the queue has a compulsory merge_bvec_fn function.
2322 * If this function returns 0, then the device is either a non-dm
2323 * device without a merge_bvec_fn, or it is a dm device that is
2324 * able to split any bios it receives that are too big.
2326 int dm_queue_merge_is_compulsory(struct request_queue *q)
2328 struct mapped_device *dev_md;
2330 if (!q->merge_bvec_fn)
2333 if (q->make_request_fn == dm_make_request) {
2334 dev_md = q->queuedata;
2335 if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
2342 static int dm_device_merge_is_compulsory(struct dm_target *ti,
2343 struct dm_dev *dev, sector_t start,
2344 sector_t len, void *data)
2346 struct block_device *bdev = dev->bdev;
2347 struct request_queue *q = bdev_get_queue(bdev);
2349 return dm_queue_merge_is_compulsory(q);
2353 * Return 1 if it is acceptable to ignore merge_bvec_fn based
2354 * on the properties of the underlying devices.
2356 static int dm_table_merge_is_optional(struct dm_table *table)
2359 struct dm_target *ti;
2361 while (i < dm_table_get_num_targets(table)) {
2362 ti = dm_table_get_target(table, i++);
2364 if (ti->type->iterate_devices &&
2365 ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
2373 * Returns old map, which caller must destroy.
2375 static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
2376 struct queue_limits *limits)
2378 struct dm_table *old_map;
2379 struct request_queue *q = md->queue;
2381 int merge_is_optional;
2383 size = dm_table_get_size(t);
2386 * Wipe any geometry if the size of the table changed.
2388 if (size != dm_get_size(md))
2389 memset(&md->geometry, 0, sizeof(md->geometry));
2391 __set_size(md, size);
2393 dm_table_event_callback(t, event_callback, md);
2396 * The queue hasn't been stopped yet, if the old table type wasn't
2397 * for request-based during suspension. So stop it to prevent
2398 * I/O mapping before resume.
2399 * This must be done before setting the queue restrictions,
2400 * because request-based dm may be run just after the setting.
2402 if (dm_table_request_based(t) && !blk_queue_stopped(q))
2405 __bind_mempools(md, t);
2407 merge_is_optional = dm_table_merge_is_optional(t);
2409 old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
2410 rcu_assign_pointer(md->map, t);
2411 md->immutable_target_type = dm_table_get_immutable_target_type(t);
2413 dm_table_set_restrictions(t, q, limits);
2414 if (merge_is_optional)
2415 set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2417 clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2425 * Returns unbound table for the caller to free.
2427 static struct dm_table *__unbind(struct mapped_device *md)
2429 struct dm_table *map = rcu_dereference_protected(md->map, 1);
2434 dm_table_event_callback(map, NULL, NULL);
2435 RCU_INIT_POINTER(md->map, NULL);
2442 * Constructor for a new device.
2444 int dm_create(int minor, struct mapped_device **result)
2446 struct mapped_device *md;
2448 md = alloc_dev(minor);
2459 * Functions to manage md->type.
2460 * All are required to hold md->type_lock.
2462 void dm_lock_md_type(struct mapped_device *md)
2464 mutex_lock(&md->type_lock);
2467 void dm_unlock_md_type(struct mapped_device *md)
2469 mutex_unlock(&md->type_lock);
2472 void dm_set_md_type(struct mapped_device *md, unsigned type)
2474 BUG_ON(!mutex_is_locked(&md->type_lock));
2478 unsigned dm_get_md_type(struct mapped_device *md)
2480 BUG_ON(!mutex_is_locked(&md->type_lock));
2484 static bool dm_md_type_request_based(struct mapped_device *md)
2486 unsigned table_type = dm_get_md_type(md);
2488 return (table_type == DM_TYPE_REQUEST_BASED ||
2489 table_type == DM_TYPE_MQ_REQUEST_BASED);
2492 struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
2494 return md->immutable_target_type;
2498 * The queue_limits are only valid as long as you have a reference
2501 struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
2503 BUG_ON(!atomic_read(&md->holders));
2504 return &md->queue->limits;
2506 EXPORT_SYMBOL_GPL(dm_get_queue_limits);
2509 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2511 static int dm_init_request_based_queue(struct mapped_device *md)
2513 struct request_queue *q = NULL;
2515 if (md->queue->elevator)
2518 /* Fully initialize the queue */
2519 q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
2524 dm_init_md_queue(md);
2525 blk_queue_softirq_done(md->queue, dm_softirq_done);
2526 blk_queue_prep_rq(md->queue, dm_prep_fn);
2528 /* Also initialize the request-based DM worker thread */
2529 init_kthread_worker(&md->kworker);
2530 md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
2531 "kdmwork-%s", dm_device_name(md));
2533 elv_register_queue(md->queue);
2539 * Setup the DM device's queue based on md's type
2541 int dm_setup_md_queue(struct mapped_device *md)
2543 if (dm_md_type_request_based(md)) {
2544 if (!dm_init_request_based_queue(md)) {
2545 DMWARN("Cannot initialize queue for request-based mapped device");
2549 /* bio-based specific initialization */
2550 blk_queue_make_request(md->queue, dm_make_request);
2551 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
2557 struct mapped_device *dm_get_md(dev_t dev)
2559 struct mapped_device *md;
2560 unsigned minor = MINOR(dev);
2562 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2565 spin_lock(&_minor_lock);
2567 md = idr_find(&_minor_idr, minor);
2569 if ((md == MINOR_ALLOCED ||
2570 (MINOR(disk_devt(dm_disk(md))) != minor) ||
2571 dm_deleting_md(md) ||
2572 test_bit(DMF_FREEING, &md->flags))) {
2580 spin_unlock(&_minor_lock);
2584 EXPORT_SYMBOL_GPL(dm_get_md);
2586 void *dm_get_mdptr(struct mapped_device *md)
2588 return md->interface_ptr;
2591 void dm_set_mdptr(struct mapped_device *md, void *ptr)
2593 md->interface_ptr = ptr;
2596 void dm_get(struct mapped_device *md)
2598 atomic_inc(&md->holders);
2599 BUG_ON(test_bit(DMF_FREEING, &md->flags));
2602 int dm_hold(struct mapped_device *md)
2604 spin_lock(&_minor_lock);
2605 if (test_bit(DMF_FREEING, &md->flags)) {
2606 spin_unlock(&_minor_lock);
2610 spin_unlock(&_minor_lock);
2613 EXPORT_SYMBOL_GPL(dm_hold);
2615 const char *dm_device_name(struct mapped_device *md)
2619 EXPORT_SYMBOL_GPL(dm_device_name);
2621 static void __dm_destroy(struct mapped_device *md, bool wait)
2623 struct dm_table *map;
2628 map = dm_get_live_table(md, &srcu_idx);
2630 spin_lock(&_minor_lock);
2631 idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
2632 set_bit(DMF_FREEING, &md->flags);
2633 spin_unlock(&_minor_lock);
2635 if (dm_request_based(md))
2636 flush_kthread_worker(&md->kworker);
2639 * Take suspend_lock so that presuspend and postsuspend methods
2640 * do not race with internal suspend.
2642 mutex_lock(&md->suspend_lock);
2643 if (!dm_suspended_md(md)) {
2644 dm_table_presuspend_targets(map);
2645 dm_table_postsuspend_targets(map);
2647 mutex_unlock(&md->suspend_lock);
2649 /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
2650 dm_put_live_table(md, srcu_idx);
2653 * Rare, but there may be I/O requests still going to complete,
2654 * for example. Wait for all references to disappear.
2655 * No one should increment the reference count of the mapped_device,
2656 * after the mapped_device state becomes DMF_FREEING.
2659 while (atomic_read(&md->holders))
2661 else if (atomic_read(&md->holders))
2662 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2663 dm_device_name(md), atomic_read(&md->holders));
2666 dm_table_destroy(__unbind(md));
2670 void dm_destroy(struct mapped_device *md)
2672 __dm_destroy(md, true);
2675 void dm_destroy_immediate(struct mapped_device *md)
2677 __dm_destroy(md, false);
2680 void dm_put(struct mapped_device *md)
2682 atomic_dec(&md->holders);
2684 EXPORT_SYMBOL_GPL(dm_put);
2686 static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2689 DECLARE_WAITQUEUE(wait, current);
2691 add_wait_queue(&md->wait, &wait);
2694 set_current_state(interruptible);
2696 if (!md_in_flight(md))
2699 if (interruptible == TASK_INTERRUPTIBLE &&
2700 signal_pending(current)) {
2707 set_current_state(TASK_RUNNING);
2709 remove_wait_queue(&md->wait, &wait);
2715 * Process the deferred bios
2717 static void dm_wq_work(struct work_struct *work)
2719 struct mapped_device *md = container_of(work, struct mapped_device,
2723 struct dm_table *map;
2725 map = dm_get_live_table(md, &srcu_idx);
2727 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2728 spin_lock_irq(&md->deferred_lock);
2729 c = bio_list_pop(&md->deferred);
2730 spin_unlock_irq(&md->deferred_lock);
2735 if (dm_request_based(md))
2736 generic_make_request(c);
2738 __split_and_process_bio(md, map, c);
2741 dm_put_live_table(md, srcu_idx);
2744 static void dm_queue_flush(struct mapped_device *md)
2746 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2747 smp_mb__after_atomic();
2748 queue_work(md->wq, &md->work);
2752 * Swap in a new table, returning the old one for the caller to destroy.
2754 struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
2756 struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
2757 struct queue_limits limits;
2760 mutex_lock(&md->suspend_lock);
2762 /* device must be suspended */
2763 if (!dm_suspended_md(md))
2767 * If the new table has no data devices, retain the existing limits.
2768 * This helps multipath with queue_if_no_path if all paths disappear,
2769 * then new I/O is queued based on these limits, and then some paths
2772 if (dm_table_has_no_data_devices(table)) {
2773 live_map = dm_get_live_table_fast(md);
2775 limits = md->queue->limits;
2776 dm_put_live_table_fast(md);
2780 r = dm_calculate_queue_limits(table, &limits);
2787 map = __bind(md, table, &limits);
2790 mutex_unlock(&md->suspend_lock);
2795 * Functions to lock and unlock any filesystem running on the
2798 static int lock_fs(struct mapped_device *md)
2802 WARN_ON(md->frozen_sb);
2804 md->frozen_sb = freeze_bdev(md->bdev);
2805 if (IS_ERR(md->frozen_sb)) {
2806 r = PTR_ERR(md->frozen_sb);
2807 md->frozen_sb = NULL;
2811 set_bit(DMF_FROZEN, &md->flags);
2816 static void unlock_fs(struct mapped_device *md)
2818 if (!test_bit(DMF_FROZEN, &md->flags))
2821 thaw_bdev(md->bdev, md->frozen_sb);
2822 md->frozen_sb = NULL;
2823 clear_bit(DMF_FROZEN, &md->flags);
2827 * If __dm_suspend returns 0, the device is completely quiescent
2828 * now. There is no request-processing activity. All new requests
2829 * are being added to md->deferred list.
2831 * Caller must hold md->suspend_lock
2833 static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
2834 unsigned suspend_flags, int interruptible)
2836 bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
2837 bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
2841 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2842 * This flag is cleared before dm_suspend returns.
2845 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2848 * This gets reverted if there's an error later and the targets
2849 * provide the .presuspend_undo hook.
2851 dm_table_presuspend_targets(map);
2854 * Flush I/O to the device.
2855 * Any I/O submitted after lock_fs() may not be flushed.
2856 * noflush takes precedence over do_lockfs.
2857 * (lock_fs() flushes I/Os and waits for them to complete.)
2859 if (!noflush && do_lockfs) {
2862 dm_table_presuspend_undo_targets(map);
2868 * Here we must make sure that no processes are submitting requests
2869 * to target drivers i.e. no one may be executing
2870 * __split_and_process_bio. This is called from dm_request and
2873 * To get all processes out of __split_and_process_bio in dm_request,
2874 * we take the write lock. To prevent any process from reentering
2875 * __split_and_process_bio from dm_request and quiesce the thread
2876 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
2877 * flush_workqueue(md->wq).
2879 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2881 synchronize_srcu(&md->io_barrier);
2884 * Stop md->queue before flushing md->wq in case request-based
2885 * dm defers requests to md->wq from md->queue.
2887 if (dm_request_based(md)) {
2888 stop_queue(md->queue);
2889 flush_kthread_worker(&md->kworker);
2892 flush_workqueue(md->wq);
2895 * At this point no more requests are entering target request routines.
2896 * We call dm_wait_for_completion to wait for all existing requests
2899 r = dm_wait_for_completion(md, interruptible);
2902 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2904 synchronize_srcu(&md->io_barrier);
2906 /* were we interrupted ? */
2910 if (dm_request_based(md))
2911 start_queue(md->queue);
2914 dm_table_presuspend_undo_targets(map);
2915 /* pushback list is already flushed, so skip flush */
2922 * We need to be able to change a mapping table under a mounted
2923 * filesystem. For example we might want to move some data in
2924 * the background. Before the table can be swapped with
2925 * dm_bind_table, dm_suspend must be called to flush any in
2926 * flight bios and ensure that any further io gets deferred.
2929 * Suspend mechanism in request-based dm.
2931 * 1. Flush all I/Os by lock_fs() if needed.
2932 * 2. Stop dispatching any I/O by stopping the request_queue.
2933 * 3. Wait for all in-flight I/Os to be completed or requeued.
2935 * To abort suspend, start the request_queue.
2937 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
2939 struct dm_table *map = NULL;
2943 mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
2945 if (dm_suspended_md(md)) {
2950 if (dm_suspended_internally_md(md)) {
2951 /* already internally suspended, wait for internal resume */
2952 mutex_unlock(&md->suspend_lock);
2953 r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
2959 map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
2961 r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE);
2965 set_bit(DMF_SUSPENDED, &md->flags);
2967 dm_table_postsuspend_targets(map);
2970 mutex_unlock(&md->suspend_lock);
2974 static int __dm_resume(struct mapped_device *md, struct dm_table *map)
2977 int r = dm_table_resume_targets(map);
2985 * Flushing deferred I/Os must be done after targets are resumed
2986 * so that mapping of targets can work correctly.
2987 * Request-based dm is queueing the deferred I/Os in its request_queue.
2989 if (dm_request_based(md))
2990 start_queue(md->queue);
2997 int dm_resume(struct mapped_device *md)
3000 struct dm_table *map = NULL;
3003 mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
3005 if (!dm_suspended_md(md))
3008 if (dm_suspended_internally_md(md)) {
3009 /* already internally suspended, wait for internal resume */
3010 mutex_unlock(&md->suspend_lock);
3011 r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
3017 map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
3018 if (!map || !dm_table_get_size(map))
3021 r = __dm_resume(md, map);
3025 clear_bit(DMF_SUSPENDED, &md->flags);
3029 mutex_unlock(&md->suspend_lock);
3035 * Internal suspend/resume works like userspace-driven suspend. It waits
3036 * until all bios finish and prevents issuing new bios to the target drivers.
3037 * It may be used only from the kernel.
3040 static void __dm_internal_suspend(struct mapped_device *md, unsigned suspend_flags)
3042 struct dm_table *map = NULL;
3044 if (md->internal_suspend_count++)
3045 return; /* nested internal suspend */
3047 if (dm_suspended_md(md)) {
3048 set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
3049 return; /* nest suspend */
3052 map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
3055 * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
3056 * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
3057 * would require changing .presuspend to return an error -- avoid this
3058 * until there is a need for more elaborate variants of internal suspend.
3060 (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE);
3062 set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
3064 dm_table_postsuspend_targets(map);
3067 static void __dm_internal_resume(struct mapped_device *md)
3069 BUG_ON(!md->internal_suspend_count);
3071 if (--md->internal_suspend_count)
3072 return; /* resume from nested internal suspend */
3074 if (dm_suspended_md(md))
3075 goto done; /* resume from nested suspend */
3078 * NOTE: existing callers don't need to call dm_table_resume_targets
3079 * (which may fail -- so best to avoid it for now by passing NULL map)
3081 (void) __dm_resume(md, NULL);
3084 clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
3085 smp_mb__after_atomic();
3086 wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
3089 void dm_internal_suspend_noflush(struct mapped_device *md)
3091 mutex_lock(&md->suspend_lock);
3092 __dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
3093 mutex_unlock(&md->suspend_lock);
3095 EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
3097 void dm_internal_resume(struct mapped_device *md)
3099 mutex_lock(&md->suspend_lock);
3100 __dm_internal_resume(md);
3101 mutex_unlock(&md->suspend_lock);
3103 EXPORT_SYMBOL_GPL(dm_internal_resume);
3106 * Fast variants of internal suspend/resume hold md->suspend_lock,
3107 * which prevents interaction with userspace-driven suspend.
3110 void dm_internal_suspend_fast(struct mapped_device *md)
3112 mutex_lock(&md->suspend_lock);
3113 if (dm_suspended_md(md) || dm_suspended_internally_md(md))
3116 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
3117 synchronize_srcu(&md->io_barrier);
3118 flush_workqueue(md->wq);
3119 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
3121 EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
3123 void dm_internal_resume_fast(struct mapped_device *md)
3125 if (dm_suspended_md(md) || dm_suspended_internally_md(md))
3131 mutex_unlock(&md->suspend_lock);
3133 EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
3135 /*-----------------------------------------------------------------
3136 * Event notification.
3137 *---------------------------------------------------------------*/
3138 int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
3141 char udev_cookie[DM_COOKIE_LENGTH];
3142 char *envp[] = { udev_cookie, NULL };
3145 return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
3147 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
3148 DM_COOKIE_ENV_VAR_NAME, cookie);
3149 return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
3154 uint32_t dm_next_uevent_seq(struct mapped_device *md)
3156 return atomic_add_return(1, &md->uevent_seq);
3159 uint32_t dm_get_event_nr(struct mapped_device *md)
3161 return atomic_read(&md->event_nr);
3164 int dm_wait_event(struct mapped_device *md, int event_nr)
3166 return wait_event_interruptible(md->eventq,
3167 (event_nr != atomic_read(&md->event_nr)));
3170 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
3172 unsigned long flags;
3174 spin_lock_irqsave(&md->uevent_lock, flags);
3175 list_add(elist, &md->uevent_list);
3176 spin_unlock_irqrestore(&md->uevent_lock, flags);
3180 * The gendisk is only valid as long as you have a reference
3183 struct gendisk *dm_disk(struct mapped_device *md)
3188 struct kobject *dm_kobject(struct mapped_device *md)
3190 return &md->kobj_holder.kobj;
3193 struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
3195 struct mapped_device *md;
3197 md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
3199 if (test_bit(DMF_FREEING, &md->flags) ||
3207 int dm_suspended_md(struct mapped_device *md)
3209 return test_bit(DMF_SUSPENDED, &md->flags);
3212 int dm_suspended_internally_md(struct mapped_device *md)
3214 return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
3217 int dm_test_deferred_remove_flag(struct mapped_device *md)
3219 return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
3222 int dm_suspended(struct dm_target *ti)
3224 return dm_suspended_md(dm_table_get_md(ti->table));
3226 EXPORT_SYMBOL_GPL(dm_suspended);
3228 int dm_noflush_suspending(struct dm_target *ti)
3230 return __noflush_suspending(dm_table_get_md(ti->table));
3232 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
3234 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size)
3236 struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
3237 struct kmem_cache *cachep;
3238 unsigned int pool_size = 0;
3239 unsigned int front_pad;
3245 case DM_TYPE_BIO_BASED:
3247 pool_size = dm_get_reserved_bio_based_ios();
3248 front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
3250 case DM_TYPE_REQUEST_BASED:
3251 pool_size = dm_get_reserved_rq_based_ios();
3252 pools->rq_pool = mempool_create_slab_pool(pool_size, _rq_cache);
3253 if (!pools->rq_pool)
3255 /* fall through to setup remaining rq-based pools */
3256 case DM_TYPE_MQ_REQUEST_BASED:
3257 cachep = _rq_tio_cache;
3259 pool_size = dm_get_reserved_rq_based_ios();
3260 front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
3261 /* per_bio_data_size is not used. See __bind_mempools(). */
3262 WARN_ON(per_bio_data_size != 0);
3268 pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
3269 if (!pools->io_pool)
3272 pools->bs = bioset_create_nobvec(pool_size, front_pad);
3276 if (integrity && bioset_integrity_create(pools->bs, pool_size))
3282 dm_free_md_mempools(pools);
3287 void dm_free_md_mempools(struct dm_md_mempools *pools)
3293 mempool_destroy(pools->io_pool);
3296 mempool_destroy(pools->rq_pool);
3299 bioset_free(pools->bs);
3304 static const struct block_device_operations dm_blk_dops = {
3305 .open = dm_blk_open,
3306 .release = dm_blk_close,
3307 .ioctl = dm_blk_ioctl,
3308 .getgeo = dm_blk_getgeo,
3309 .owner = THIS_MODULE
3315 module_init(dm_init);
3316 module_exit(dm_exit);
3318 module_param(major, uint, 0);
3319 MODULE_PARM_DESC(major, "The major number of the device mapper");
3321 module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
3322 MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
3324 module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
3325 MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
3327 MODULE_DESCRIPTION(DM_NAME " driver");
3328 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3329 MODULE_LICENSE("GPL");