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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
4 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
5 *
6 * This file is released under the GPL.
7 */
8
9#include "dm-core.h"
10#include "dm-rq.h"
11#include "dm-uevent.h"
12#include "dm-ima.h"
13
14#include <linux/init.h>
15#include <linux/module.h>
16#include <linux/mutex.h>
17#include <linux/sched/mm.h>
18#include <linux/sched/signal.h>
19#include <linux/blkpg.h>
20#include <linux/bio.h>
21#include <linux/mempool.h>
22#include <linux/dax.h>
23#include <linux/slab.h>
24#include <linux/idr.h>
25#include <linux/uio.h>
26#include <linux/hdreg.h>
27#include <linux/delay.h>
28#include <linux/wait.h>
29#include <linux/pr.h>
30#include <linux/refcount.h>
31#include <linux/part_stat.h>
32#include <linux/blk-crypto.h>
33#include <linux/blk-crypto-profile.h>
34
35#define DM_MSG_PREFIX "core"
36
37/*
38 * Cookies are numeric values sent with CHANGE and REMOVE
39 * uevents while resuming, removing or renaming the device.
40 */
41#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
42#define DM_COOKIE_LENGTH 24
43
44/*
45 * For REQ_POLLED fs bio, this flag is set if we link mapped underlying
46 * dm_io into one list, and reuse bio->bi_private as the list head. Before
47 * ending this fs bio, we will recover its ->bi_private.
48 */
49#define REQ_DM_POLL_LIST REQ_DRV
50
51static const char *_name = DM_NAME;
52
53static unsigned int major;
54static unsigned int _major;
55
56static DEFINE_IDR(_minor_idr);
57
58static DEFINE_SPINLOCK(_minor_lock);
59
60static void do_deferred_remove(struct work_struct *w);
61
62static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
63
64static struct workqueue_struct *deferred_remove_workqueue;
65
66atomic_t dm_global_event_nr = ATOMIC_INIT(0);
67DECLARE_WAIT_QUEUE_HEAD(dm_global_eventq);
68
69void dm_issue_global_event(void)
70{
71 atomic_inc(&dm_global_event_nr);
72 wake_up(&dm_global_eventq);
73}
74
75DEFINE_STATIC_KEY_FALSE(stats_enabled);
76DEFINE_STATIC_KEY_FALSE(swap_bios_enabled);
77DEFINE_STATIC_KEY_FALSE(zoned_enabled);
78
79/*
80 * One of these is allocated (on-stack) per original bio.
81 */
82struct clone_info {
83 struct dm_table *map;
84 struct bio *bio;
85 struct dm_io *io;
86 sector_t sector;
87 unsigned int sector_count;
88 bool is_abnormal_io:1;
89 bool submit_as_polled:1;
90};
91
92static inline struct dm_target_io *clone_to_tio(struct bio *clone)
93{
94 return container_of(clone, struct dm_target_io, clone);
95}
96
97void *dm_per_bio_data(struct bio *bio, size_t data_size)
98{
99 if (!dm_tio_flagged(clone_to_tio(bio), DM_TIO_INSIDE_DM_IO))
100 return (char *)bio - DM_TARGET_IO_BIO_OFFSET - data_size;
101 return (char *)bio - DM_IO_BIO_OFFSET - data_size;
102}
103EXPORT_SYMBOL_GPL(dm_per_bio_data);
104
105struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size)
106{
107 struct dm_io *io = (struct dm_io *)((char *)data + data_size);
108
109 if (io->magic == DM_IO_MAGIC)
110 return (struct bio *)((char *)io + DM_IO_BIO_OFFSET);
111 BUG_ON(io->magic != DM_TIO_MAGIC);
112 return (struct bio *)((char *)io + DM_TARGET_IO_BIO_OFFSET);
113}
114EXPORT_SYMBOL_GPL(dm_bio_from_per_bio_data);
115
116unsigned int dm_bio_get_target_bio_nr(const struct bio *bio)
117{
118 return container_of(bio, struct dm_target_io, clone)->target_bio_nr;
119}
120EXPORT_SYMBOL_GPL(dm_bio_get_target_bio_nr);
121
122#define MINOR_ALLOCED ((void *)-1)
123
124#define DM_NUMA_NODE NUMA_NO_NODE
125static int dm_numa_node = DM_NUMA_NODE;
126
127#define DEFAULT_SWAP_BIOS (8 * 1048576 / PAGE_SIZE)
128static int swap_bios = DEFAULT_SWAP_BIOS;
129static int get_swap_bios(void)
130{
131 int latch = READ_ONCE(swap_bios);
132
133 if (unlikely(latch <= 0))
134 latch = DEFAULT_SWAP_BIOS;
135 return latch;
136}
137
138struct table_device {
139 struct list_head list;
140 refcount_t count;
141 struct dm_dev dm_dev;
142};
143
144/*
145 * Bio-based DM's mempools' reserved IOs set by the user.
146 */
147#define RESERVED_BIO_BASED_IOS 16
148static unsigned int reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
149
150static int __dm_get_module_param_int(int *module_param, int min, int max)
151{
152 int param = READ_ONCE(*module_param);
153 int modified_param = 0;
154 bool modified = true;
155
156 if (param < min)
157 modified_param = min;
158 else if (param > max)
159 modified_param = max;
160 else
161 modified = false;
162
163 if (modified) {
164 (void)cmpxchg(module_param, param, modified_param);
165 param = modified_param;
166 }
167
168 return param;
169}
170
171unsigned int __dm_get_module_param(unsigned int *module_param, unsigned int def, unsigned int max)
172{
173 unsigned int param = READ_ONCE(*module_param);
174 unsigned int modified_param = 0;
175
176 if (!param)
177 modified_param = def;
178 else if (param > max)
179 modified_param = max;
180
181 if (modified_param) {
182 (void)cmpxchg(module_param, param, modified_param);
183 param = modified_param;
184 }
185
186 return param;
187}
188
189unsigned int dm_get_reserved_bio_based_ios(void)
190{
191 return __dm_get_module_param(&reserved_bio_based_ios,
192 RESERVED_BIO_BASED_IOS, DM_RESERVED_MAX_IOS);
193}
194EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
195
196static unsigned int dm_get_numa_node(void)
197{
198 return __dm_get_module_param_int(&dm_numa_node,
199 DM_NUMA_NODE, num_online_nodes() - 1);
200}
201
202static int __init local_init(void)
203{
204 int r;
205
206 r = dm_uevent_init();
207 if (r)
208 return r;
209
210 deferred_remove_workqueue = alloc_ordered_workqueue("kdmremove", 0);
211 if (!deferred_remove_workqueue) {
212 r = -ENOMEM;
213 goto out_uevent_exit;
214 }
215
216 _major = major;
217 r = register_blkdev(_major, _name);
218 if (r < 0)
219 goto out_free_workqueue;
220
221 if (!_major)
222 _major = r;
223
224 return 0;
225
226out_free_workqueue:
227 destroy_workqueue(deferred_remove_workqueue);
228out_uevent_exit:
229 dm_uevent_exit();
230
231 return r;
232}
233
234static void local_exit(void)
235{
236 destroy_workqueue(deferred_remove_workqueue);
237
238 unregister_blkdev(_major, _name);
239 dm_uevent_exit();
240
241 _major = 0;
242
243 DMINFO("cleaned up");
244}
245
246static int (*_inits[])(void) __initdata = {
247 local_init,
248 dm_target_init,
249 dm_linear_init,
250 dm_stripe_init,
251 dm_io_init,
252 dm_kcopyd_init,
253 dm_interface_init,
254 dm_statistics_init,
255};
256
257static void (*_exits[])(void) = {
258 local_exit,
259 dm_target_exit,
260 dm_linear_exit,
261 dm_stripe_exit,
262 dm_io_exit,
263 dm_kcopyd_exit,
264 dm_interface_exit,
265 dm_statistics_exit,
266};
267
268static int __init dm_init(void)
269{
270 const int count = ARRAY_SIZE(_inits);
271 int r, i;
272
273#if (IS_ENABLED(CONFIG_IMA) && !IS_ENABLED(CONFIG_IMA_DISABLE_HTABLE))
274 DMWARN("CONFIG_IMA_DISABLE_HTABLE is disabled."
275 " Duplicate IMA measurements will not be recorded in the IMA log.");
276#endif
277
278 for (i = 0; i < count; i++) {
279 r = _inits[i]();
280 if (r)
281 goto bad;
282 }
283
284 return 0;
285bad:
286 while (i--)
287 _exits[i]();
288
289 return r;
290}
291
292static void __exit dm_exit(void)
293{
294 int i = ARRAY_SIZE(_exits);
295
296 while (i--)
297 _exits[i]();
298
299 /*
300 * Should be empty by this point.
301 */
302 idr_destroy(&_minor_idr);
303}
304
305/*
306 * Block device functions
307 */
308int dm_deleting_md(struct mapped_device *md)
309{
310 return test_bit(DMF_DELETING, &md->flags);
311}
312
313static int dm_blk_open(struct gendisk *disk, blk_mode_t mode)
314{
315 struct mapped_device *md;
316
317 spin_lock(&_minor_lock);
318
319 md = disk->private_data;
320 if (!md)
321 goto out;
322
323 if (test_bit(DMF_FREEING, &md->flags) ||
324 dm_deleting_md(md)) {
325 md = NULL;
326 goto out;
327 }
328
329 dm_get(md);
330 atomic_inc(&md->open_count);
331out:
332 spin_unlock(&_minor_lock);
333
334 return md ? 0 : -ENXIO;
335}
336
337static void dm_blk_close(struct gendisk *disk)
338{
339 struct mapped_device *md;
340
341 spin_lock(&_minor_lock);
342
343 md = disk->private_data;
344 if (WARN_ON(!md))
345 goto out;
346
347 if (atomic_dec_and_test(&md->open_count) &&
348 (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
349 queue_work(deferred_remove_workqueue, &deferred_remove_work);
350
351 dm_put(md);
352out:
353 spin_unlock(&_minor_lock);
354}
355
356int dm_open_count(struct mapped_device *md)
357{
358 return atomic_read(&md->open_count);
359}
360
361/*
362 * Guarantees nothing is using the device before it's deleted.
363 */
364int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
365{
366 int r = 0;
367
368 spin_lock(&_minor_lock);
369
370 if (dm_open_count(md)) {
371 r = -EBUSY;
372 if (mark_deferred)
373 set_bit(DMF_DEFERRED_REMOVE, &md->flags);
374 } else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
375 r = -EEXIST;
376 else
377 set_bit(DMF_DELETING, &md->flags);
378
379 spin_unlock(&_minor_lock);
380
381 return r;
382}
383
384int dm_cancel_deferred_remove(struct mapped_device *md)
385{
386 int r = 0;
387
388 spin_lock(&_minor_lock);
389
390 if (test_bit(DMF_DELETING, &md->flags))
391 r = -EBUSY;
392 else
393 clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
394
395 spin_unlock(&_minor_lock);
396
397 return r;
398}
399
400static void do_deferred_remove(struct work_struct *w)
401{
402 dm_deferred_remove();
403}
404
405static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
406{
407 struct mapped_device *md = bdev->bd_disk->private_data;
408
409 return dm_get_geometry(md, geo);
410}
411
412static int dm_prepare_ioctl(struct mapped_device *md, int *srcu_idx,
413 struct block_device **bdev)
414{
415 struct dm_target *ti;
416 struct dm_table *map;
417 int r;
418
419retry:
420 r = -ENOTTY;
421 map = dm_get_live_table(md, srcu_idx);
422 if (!map || !dm_table_get_size(map))
423 return r;
424
425 /* We only support devices that have a single target */
426 if (map->num_targets != 1)
427 return r;
428
429 ti = dm_table_get_target(map, 0);
430 if (!ti->type->prepare_ioctl)
431 return r;
432
433 if (dm_suspended_md(md))
434 return -EAGAIN;
435
436 r = ti->type->prepare_ioctl(ti, bdev);
437 if (r == -ENOTCONN && !fatal_signal_pending(current)) {
438 dm_put_live_table(md, *srcu_idx);
439 fsleep(10000);
440 goto retry;
441 }
442
443 return r;
444}
445
446static void dm_unprepare_ioctl(struct mapped_device *md, int srcu_idx)
447{
448 dm_put_live_table(md, srcu_idx);
449}
450
451static int dm_blk_ioctl(struct block_device *bdev, blk_mode_t mode,
452 unsigned int cmd, unsigned long arg)
453{
454 struct mapped_device *md = bdev->bd_disk->private_data;
455 int r, srcu_idx;
456
457 r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
458 if (r < 0)
459 goto out;
460
461 if (r > 0) {
462 /*
463 * Target determined this ioctl is being issued against a
464 * subset of the parent bdev; require extra privileges.
465 */
466 if (!capable(CAP_SYS_RAWIO)) {
467 DMDEBUG_LIMIT(
468 "%s: sending ioctl %x to DM device without required privilege.",
469 current->comm, cmd);
470 r = -ENOIOCTLCMD;
471 goto out;
472 }
473 }
474
475 if (!bdev->bd_disk->fops->ioctl)
476 r = -ENOTTY;
477 else
478 r = bdev->bd_disk->fops->ioctl(bdev, mode, cmd, arg);
479out:
480 dm_unprepare_ioctl(md, srcu_idx);
481 return r;
482}
483
484u64 dm_start_time_ns_from_clone(struct bio *bio)
485{
486 return jiffies_to_nsecs(clone_to_tio(bio)->io->start_time);
487}
488EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone);
489
490static inline bool bio_is_flush_with_data(struct bio *bio)
491{
492 return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size);
493}
494
495static inline unsigned int dm_io_sectors(struct dm_io *io, struct bio *bio)
496{
497 /*
498 * If REQ_PREFLUSH set, don't account payload, it will be
499 * submitted (and accounted) after this flush completes.
500 */
501 if (bio_is_flush_with_data(bio))
502 return 0;
503 if (unlikely(dm_io_flagged(io, DM_IO_WAS_SPLIT)))
504 return io->sectors;
505 return bio_sectors(bio);
506}
507
508static void dm_io_acct(struct dm_io *io, bool end)
509{
510 struct bio *bio = io->orig_bio;
511
512 if (dm_io_flagged(io, DM_IO_BLK_STAT)) {
513 if (!end)
514 bdev_start_io_acct(bio->bi_bdev, bio_op(bio),
515 io->start_time);
516 else
517 bdev_end_io_acct(bio->bi_bdev, bio_op(bio),
518 dm_io_sectors(io, bio),
519 io->start_time);
520 }
521
522 if (static_branch_unlikely(&stats_enabled) &&
523 unlikely(dm_stats_used(&io->md->stats))) {
524 sector_t sector;
525
526 if (unlikely(dm_io_flagged(io, DM_IO_WAS_SPLIT)))
527 sector = bio_end_sector(bio) - io->sector_offset;
528 else
529 sector = bio->bi_iter.bi_sector;
530
531 dm_stats_account_io(&io->md->stats, bio_data_dir(bio),
532 sector, dm_io_sectors(io, bio),
533 end, io->start_time, &io->stats_aux);
534 }
535}
536
537static void __dm_start_io_acct(struct dm_io *io)
538{
539 dm_io_acct(io, false);
540}
541
542static void dm_start_io_acct(struct dm_io *io, struct bio *clone)
543{
544 /*
545 * Ensure IO accounting is only ever started once.
546 */
547 if (dm_io_flagged(io, DM_IO_ACCOUNTED))
548 return;
549
550 /* Expect no possibility for race unless DM_TIO_IS_DUPLICATE_BIO. */
551 if (!clone || likely(dm_tio_is_normal(clone_to_tio(clone)))) {
552 dm_io_set_flag(io, DM_IO_ACCOUNTED);
553 } else {
554 unsigned long flags;
555 /* Can afford locking given DM_TIO_IS_DUPLICATE_BIO */
556 spin_lock_irqsave(&io->lock, flags);
557 if (dm_io_flagged(io, DM_IO_ACCOUNTED)) {
558 spin_unlock_irqrestore(&io->lock, flags);
559 return;
560 }
561 dm_io_set_flag(io, DM_IO_ACCOUNTED);
562 spin_unlock_irqrestore(&io->lock, flags);
563 }
564
565 __dm_start_io_acct(io);
566}
567
568static void dm_end_io_acct(struct dm_io *io)
569{
570 dm_io_acct(io, true);
571}
572
573static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio, gfp_t gfp_mask)
574{
575 struct dm_io *io;
576 struct dm_target_io *tio;
577 struct bio *clone;
578
579 clone = bio_alloc_clone(NULL, bio, gfp_mask, &md->mempools->io_bs);
580 if (unlikely(!clone))
581 return NULL;
582 tio = clone_to_tio(clone);
583 tio->flags = 0;
584 dm_tio_set_flag(tio, DM_TIO_INSIDE_DM_IO);
585 tio->io = NULL;
586
587 io = container_of(tio, struct dm_io, tio);
588 io->magic = DM_IO_MAGIC;
589 io->status = BLK_STS_OK;
590
591 /* one ref is for submission, the other is for completion */
592 atomic_set(&io->io_count, 2);
593 this_cpu_inc(*md->pending_io);
594 io->orig_bio = bio;
595 io->md = md;
596 spin_lock_init(&io->lock);
597 io->start_time = jiffies;
598 io->flags = 0;
599 if (blk_queue_io_stat(md->queue))
600 dm_io_set_flag(io, DM_IO_BLK_STAT);
601
602 if (static_branch_unlikely(&stats_enabled) &&
603 unlikely(dm_stats_used(&md->stats)))
604 dm_stats_record_start(&md->stats, &io->stats_aux);
605
606 return io;
607}
608
609static void free_io(struct dm_io *io)
610{
611 bio_put(&io->tio.clone);
612}
613
614static struct bio *alloc_tio(struct clone_info *ci, struct dm_target *ti,
615 unsigned int target_bio_nr, unsigned int *len, gfp_t gfp_mask)
616{
617 struct mapped_device *md = ci->io->md;
618 struct dm_target_io *tio;
619 struct bio *clone;
620
621 if (!ci->io->tio.io) {
622 /* the dm_target_io embedded in ci->io is available */
623 tio = &ci->io->tio;
624 /* alloc_io() already initialized embedded clone */
625 clone = &tio->clone;
626 } else {
627 clone = bio_alloc_clone(NULL, ci->bio, gfp_mask,
628 &md->mempools->bs);
629 if (!clone)
630 return NULL;
631
632 /* REQ_DM_POLL_LIST shouldn't be inherited */
633 clone->bi_opf &= ~REQ_DM_POLL_LIST;
634
635 tio = clone_to_tio(clone);
636 tio->flags = 0; /* also clears DM_TIO_INSIDE_DM_IO */
637 }
638
639 tio->magic = DM_TIO_MAGIC;
640 tio->io = ci->io;
641 tio->ti = ti;
642 tio->target_bio_nr = target_bio_nr;
643 tio->len_ptr = len;
644 tio->old_sector = 0;
645
646 /* Set default bdev, but target must bio_set_dev() before issuing IO */
647 clone->bi_bdev = md->disk->part0;
648 if (unlikely(ti->needs_bio_set_dev))
649 bio_set_dev(clone, md->disk->part0);
650
651 if (len) {
652 clone->bi_iter.bi_size = to_bytes(*len);
653 if (bio_integrity(clone))
654 bio_integrity_trim(clone);
655 }
656
657 return clone;
658}
659
660static void free_tio(struct bio *clone)
661{
662 if (dm_tio_flagged(clone_to_tio(clone), DM_TIO_INSIDE_DM_IO))
663 return;
664 bio_put(clone);
665}
666
667/*
668 * Add the bio to the list of deferred io.
669 */
670static void queue_io(struct mapped_device *md, struct bio *bio)
671{
672 unsigned long flags;
673
674 spin_lock_irqsave(&md->deferred_lock, flags);
675 bio_list_add(&md->deferred, bio);
676 spin_unlock_irqrestore(&md->deferred_lock, flags);
677 queue_work(md->wq, &md->work);
678}
679
680/*
681 * Everyone (including functions in this file), should use this
682 * function to access the md->map field, and make sure they call
683 * dm_put_live_table() when finished.
684 */
685struct dm_table *dm_get_live_table(struct mapped_device *md,
686 int *srcu_idx) __acquires(md->io_barrier)
687{
688 *srcu_idx = srcu_read_lock(&md->io_barrier);
689
690 return srcu_dereference(md->map, &md->io_barrier);
691}
692
693void dm_put_live_table(struct mapped_device *md,
694 int srcu_idx) __releases(md->io_barrier)
695{
696 srcu_read_unlock(&md->io_barrier, srcu_idx);
697}
698
699void dm_sync_table(struct mapped_device *md)
700{
701 synchronize_srcu(&md->io_barrier);
702 synchronize_rcu_expedited();
703}
704
705/*
706 * A fast alternative to dm_get_live_table/dm_put_live_table.
707 * The caller must not block between these two functions.
708 */
709static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
710{
711 rcu_read_lock();
712 return rcu_dereference(md->map);
713}
714
715static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
716{
717 rcu_read_unlock();
718}
719
720static char *_dm_claim_ptr = "I belong to device-mapper";
721
722/*
723 * Open a table device so we can use it as a map destination.
724 */
725static struct table_device *open_table_device(struct mapped_device *md,
726 dev_t dev, blk_mode_t mode)
727{
728 struct table_device *td;
729 struct bdev_handle *bdev_handle;
730 u64 part_off;
731 int r;
732
733 td = kmalloc_node(sizeof(*td), GFP_KERNEL, md->numa_node_id);
734 if (!td)
735 return ERR_PTR(-ENOMEM);
736 refcount_set(&td->count, 1);
737
738 bdev_handle = bdev_open_by_dev(dev, mode, _dm_claim_ptr, NULL);
739 if (IS_ERR(bdev_handle)) {
740 r = PTR_ERR(bdev_handle);
741 goto out_free_td;
742 }
743
744 /*
745 * We can be called before the dm disk is added. In that case we can't
746 * register the holder relation here. It will be done once add_disk was
747 * called.
748 */
749 if (md->disk->slave_dir) {
750 r = bd_link_disk_holder(bdev_handle->bdev, md->disk);
751 if (r)
752 goto out_blkdev_put;
753 }
754
755 td->dm_dev.mode = mode;
756 td->dm_dev.bdev = bdev_handle->bdev;
757 td->dm_dev.bdev_handle = bdev_handle;
758 td->dm_dev.dax_dev = fs_dax_get_by_bdev(bdev_handle->bdev, &part_off,
759 NULL, NULL);
760 format_dev_t(td->dm_dev.name, dev);
761 list_add(&td->list, &md->table_devices);
762 return td;
763
764out_blkdev_put:
765 bdev_release(bdev_handle);
766out_free_td:
767 kfree(td);
768 return ERR_PTR(r);
769}
770
771/*
772 * Close a table device that we've been using.
773 */
774static void close_table_device(struct table_device *td, struct mapped_device *md)
775{
776 if (md->disk->slave_dir)
777 bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
778 bdev_release(td->dm_dev.bdev_handle);
779 put_dax(td->dm_dev.dax_dev);
780 list_del(&td->list);
781 kfree(td);
782}
783
784static struct table_device *find_table_device(struct list_head *l, dev_t dev,
785 blk_mode_t mode)
786{
787 struct table_device *td;
788
789 list_for_each_entry(td, l, list)
790 if (td->dm_dev.bdev->bd_dev == dev && td->dm_dev.mode == mode)
791 return td;
792
793 return NULL;
794}
795
796int dm_get_table_device(struct mapped_device *md, dev_t dev, blk_mode_t mode,
797 struct dm_dev **result)
798{
799 struct table_device *td;
800
801 mutex_lock(&md->table_devices_lock);
802 td = find_table_device(&md->table_devices, dev, mode);
803 if (!td) {
804 td = open_table_device(md, dev, mode);
805 if (IS_ERR(td)) {
806 mutex_unlock(&md->table_devices_lock);
807 return PTR_ERR(td);
808 }
809 } else {
810 refcount_inc(&td->count);
811 }
812 mutex_unlock(&md->table_devices_lock);
813
814 *result = &td->dm_dev;
815 return 0;
816}
817
818void dm_put_table_device(struct mapped_device *md, struct dm_dev *d)
819{
820 struct table_device *td = container_of(d, struct table_device, dm_dev);
821
822 mutex_lock(&md->table_devices_lock);
823 if (refcount_dec_and_test(&td->count))
824 close_table_device(td, md);
825 mutex_unlock(&md->table_devices_lock);
826}
827
828/*
829 * Get the geometry associated with a dm device
830 */
831int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
832{
833 *geo = md->geometry;
834
835 return 0;
836}
837
838/*
839 * Set the geometry of a device.
840 */
841int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
842{
843 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
844
845 if (geo->start > sz) {
846 DMERR("Start sector is beyond the geometry limits.");
847 return -EINVAL;
848 }
849
850 md->geometry = *geo;
851
852 return 0;
853}
854
855static int __noflush_suspending(struct mapped_device *md)
856{
857 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
858}
859
860static void dm_requeue_add_io(struct dm_io *io, bool first_stage)
861{
862 struct mapped_device *md = io->md;
863
864 if (first_stage) {
865 struct dm_io *next = md->requeue_list;
866
867 md->requeue_list = io;
868 io->next = next;
869 } else {
870 bio_list_add_head(&md->deferred, io->orig_bio);
871 }
872}
873
874static void dm_kick_requeue(struct mapped_device *md, bool first_stage)
875{
876 if (first_stage)
877 queue_work(md->wq, &md->requeue_work);
878 else
879 queue_work(md->wq, &md->work);
880}
881
882/*
883 * Return true if the dm_io's original bio is requeued.
884 * io->status is updated with error if requeue disallowed.
885 */
886static bool dm_handle_requeue(struct dm_io *io, bool first_stage)
887{
888 struct bio *bio = io->orig_bio;
889 bool handle_requeue = (io->status == BLK_STS_DM_REQUEUE);
890 bool handle_polled_eagain = ((io->status == BLK_STS_AGAIN) &&
891 (bio->bi_opf & REQ_POLLED));
892 struct mapped_device *md = io->md;
893 bool requeued = false;
894
895 if (handle_requeue || handle_polled_eagain) {
896 unsigned long flags;
897
898 if (bio->bi_opf & REQ_POLLED) {
899 /*
900 * Upper layer won't help us poll split bio
901 * (io->orig_bio may only reflect a subset of the
902 * pre-split original) so clear REQ_POLLED.
903 */
904 bio_clear_polled(bio);
905 }
906
907 /*
908 * Target requested pushing back the I/O or
909 * polled IO hit BLK_STS_AGAIN.
910 */
911 spin_lock_irqsave(&md->deferred_lock, flags);
912 if ((__noflush_suspending(md) &&
913 !WARN_ON_ONCE(dm_is_zone_write(md, bio))) ||
914 handle_polled_eagain || first_stage) {
915 dm_requeue_add_io(io, first_stage);
916 requeued = true;
917 } else {
918 /*
919 * noflush suspend was interrupted or this is
920 * a write to a zoned target.
921 */
922 io->status = BLK_STS_IOERR;
923 }
924 spin_unlock_irqrestore(&md->deferred_lock, flags);
925 }
926
927 if (requeued)
928 dm_kick_requeue(md, first_stage);
929
930 return requeued;
931}
932
933static void __dm_io_complete(struct dm_io *io, bool first_stage)
934{
935 struct bio *bio = io->orig_bio;
936 struct mapped_device *md = io->md;
937 blk_status_t io_error;
938 bool requeued;
939
940 requeued = dm_handle_requeue(io, first_stage);
941 if (requeued && first_stage)
942 return;
943
944 io_error = io->status;
945 if (dm_io_flagged(io, DM_IO_ACCOUNTED))
946 dm_end_io_acct(io);
947 else if (!io_error) {
948 /*
949 * Must handle target that DM_MAPIO_SUBMITTED only to
950 * then bio_endio() rather than dm_submit_bio_remap()
951 */
952 __dm_start_io_acct(io);
953 dm_end_io_acct(io);
954 }
955 free_io(io);
956 smp_wmb();
957 this_cpu_dec(*md->pending_io);
958
959 /* nudge anyone waiting on suspend queue */
960 if (unlikely(wq_has_sleeper(&md->wait)))
961 wake_up(&md->wait);
962
963 /* Return early if the original bio was requeued */
964 if (requeued)
965 return;
966
967 if (bio_is_flush_with_data(bio)) {
968 /*
969 * Preflush done for flush with data, reissue
970 * without REQ_PREFLUSH.
971 */
972 bio->bi_opf &= ~REQ_PREFLUSH;
973 queue_io(md, bio);
974 } else {
975 /* done with normal IO or empty flush */
976 if (io_error)
977 bio->bi_status = io_error;
978 bio_endio(bio);
979 }
980}
981
982static void dm_wq_requeue_work(struct work_struct *work)
983{
984 struct mapped_device *md = container_of(work, struct mapped_device,
985 requeue_work);
986 unsigned long flags;
987 struct dm_io *io;
988
989 /* reuse deferred lock to simplify dm_handle_requeue */
990 spin_lock_irqsave(&md->deferred_lock, flags);
991 io = md->requeue_list;
992 md->requeue_list = NULL;
993 spin_unlock_irqrestore(&md->deferred_lock, flags);
994
995 while (io) {
996 struct dm_io *next = io->next;
997
998 dm_io_rewind(io, &md->disk->bio_split);
999
1000 io->next = NULL;
1001 __dm_io_complete(io, false);
1002 io = next;
1003 cond_resched();
1004 }
1005}
1006
1007/*
1008 * Two staged requeue:
1009 *
1010 * 1) io->orig_bio points to the real original bio, and the part mapped to
1011 * this io must be requeued, instead of other parts of the original bio.
1012 *
1013 * 2) io->orig_bio points to new cloned bio which matches the requeued dm_io.
1014 */
1015static void dm_io_complete(struct dm_io *io)
1016{
1017 bool first_requeue;
1018
1019 /*
1020 * Only dm_io that has been split needs two stage requeue, otherwise
1021 * we may run into long bio clone chain during suspend and OOM could
1022 * be triggered.
1023 *
1024 * Also flush data dm_io won't be marked as DM_IO_WAS_SPLIT, so they
1025 * also aren't handled via the first stage requeue.
1026 */
1027 if (dm_io_flagged(io, DM_IO_WAS_SPLIT))
1028 first_requeue = true;
1029 else
1030 first_requeue = false;
1031
1032 __dm_io_complete(io, first_requeue);
1033}
1034
1035/*
1036 * Decrements the number of outstanding ios that a bio has been
1037 * cloned into, completing the original io if necc.
1038 */
1039static inline void __dm_io_dec_pending(struct dm_io *io)
1040{
1041 if (atomic_dec_and_test(&io->io_count))
1042 dm_io_complete(io);
1043}
1044
1045static void dm_io_set_error(struct dm_io *io, blk_status_t error)
1046{
1047 unsigned long flags;
1048
1049 /* Push-back supersedes any I/O errors */
1050 spin_lock_irqsave(&io->lock, flags);
1051 if (!(io->status == BLK_STS_DM_REQUEUE &&
1052 __noflush_suspending(io->md))) {
1053 io->status = error;
1054 }
1055 spin_unlock_irqrestore(&io->lock, flags);
1056}
1057
1058static void dm_io_dec_pending(struct dm_io *io, blk_status_t error)
1059{
1060 if (unlikely(error))
1061 dm_io_set_error(io, error);
1062
1063 __dm_io_dec_pending(io);
1064}
1065
1066/*
1067 * The queue_limits are only valid as long as you have a reference
1068 * count on 'md'. But _not_ imposing verification to avoid atomic_read(),
1069 */
1070static inline struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
1071{
1072 return &md->queue->limits;
1073}
1074
1075void disable_discard(struct mapped_device *md)
1076{
1077 struct queue_limits *limits = dm_get_queue_limits(md);
1078
1079 /* device doesn't really support DISCARD, disable it */
1080 limits->max_discard_sectors = 0;
1081}
1082
1083void disable_write_zeroes(struct mapped_device *md)
1084{
1085 struct queue_limits *limits = dm_get_queue_limits(md);
1086
1087 /* device doesn't really support WRITE ZEROES, disable it */
1088 limits->max_write_zeroes_sectors = 0;
1089}
1090
1091static bool swap_bios_limit(struct dm_target *ti, struct bio *bio)
1092{
1093 return unlikely((bio->bi_opf & REQ_SWAP) != 0) && unlikely(ti->limit_swap_bios);
1094}
1095
1096static void clone_endio(struct bio *bio)
1097{
1098 blk_status_t error = bio->bi_status;
1099 struct dm_target_io *tio = clone_to_tio(bio);
1100 struct dm_target *ti = tio->ti;
1101 dm_endio_fn endio = ti->type->end_io;
1102 struct dm_io *io = tio->io;
1103 struct mapped_device *md = io->md;
1104
1105 if (unlikely(error == BLK_STS_TARGET)) {
1106 if (bio_op(bio) == REQ_OP_DISCARD &&
1107 !bdev_max_discard_sectors(bio->bi_bdev))
1108 disable_discard(md);
1109 else if (bio_op(bio) == REQ_OP_WRITE_ZEROES &&
1110 !bdev_write_zeroes_sectors(bio->bi_bdev))
1111 disable_write_zeroes(md);
1112 }
1113
1114 if (static_branch_unlikely(&zoned_enabled) &&
1115 unlikely(bdev_is_zoned(bio->bi_bdev)))
1116 dm_zone_endio(io, bio);
1117
1118 if (endio) {
1119 int r = endio(ti, bio, &error);
1120
1121 switch (r) {
1122 case DM_ENDIO_REQUEUE:
1123 if (static_branch_unlikely(&zoned_enabled)) {
1124 /*
1125 * Requeuing writes to a sequential zone of a zoned
1126 * target will break the sequential write pattern:
1127 * fail such IO.
1128 */
1129 if (WARN_ON_ONCE(dm_is_zone_write(md, bio)))
1130 error = BLK_STS_IOERR;
1131 else
1132 error = BLK_STS_DM_REQUEUE;
1133 } else
1134 error = BLK_STS_DM_REQUEUE;
1135 fallthrough;
1136 case DM_ENDIO_DONE:
1137 break;
1138 case DM_ENDIO_INCOMPLETE:
1139 /* The target will handle the io */
1140 return;
1141 default:
1142 DMCRIT("unimplemented target endio return value: %d", r);
1143 BUG();
1144 }
1145 }
1146
1147 if (static_branch_unlikely(&swap_bios_enabled) &&
1148 unlikely(swap_bios_limit(ti, bio)))
1149 up(&md->swap_bios_semaphore);
1150
1151 free_tio(bio);
1152 dm_io_dec_pending(io, error);
1153}
1154
1155/*
1156 * Return maximum size of I/O possible at the supplied sector up to the current
1157 * target boundary.
1158 */
1159static inline sector_t max_io_len_target_boundary(struct dm_target *ti,
1160 sector_t target_offset)
1161{
1162 return ti->len - target_offset;
1163}
1164
1165static sector_t __max_io_len(struct dm_target *ti, sector_t sector,
1166 unsigned int max_granularity,
1167 unsigned int max_sectors)
1168{
1169 sector_t target_offset = dm_target_offset(ti, sector);
1170 sector_t len = max_io_len_target_boundary(ti, target_offset);
1171
1172 /*
1173 * Does the target need to split IO even further?
1174 * - varied (per target) IO splitting is a tenet of DM; this
1175 * explains why stacked chunk_sectors based splitting via
1176 * bio_split_to_limits() isn't possible here.
1177 */
1178 if (!max_granularity)
1179 return len;
1180 return min_t(sector_t, len,
1181 min(max_sectors ? : queue_max_sectors(ti->table->md->queue),
1182 blk_chunk_sectors_left(target_offset, max_granularity)));
1183}
1184
1185static inline sector_t max_io_len(struct dm_target *ti, sector_t sector)
1186{
1187 return __max_io_len(ti, sector, ti->max_io_len, 0);
1188}
1189
1190int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
1191{
1192 if (len > UINT_MAX) {
1193 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
1194 (unsigned long long)len, UINT_MAX);
1195 ti->error = "Maximum size of target IO is too large";
1196 return -EINVAL;
1197 }
1198
1199 ti->max_io_len = (uint32_t) len;
1200
1201 return 0;
1202}
1203EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
1204
1205static struct dm_target *dm_dax_get_live_target(struct mapped_device *md,
1206 sector_t sector, int *srcu_idx)
1207 __acquires(md->io_barrier)
1208{
1209 struct dm_table *map;
1210 struct dm_target *ti;
1211
1212 map = dm_get_live_table(md, srcu_idx);
1213 if (!map)
1214 return NULL;
1215
1216 ti = dm_table_find_target(map, sector);
1217 if (!ti)
1218 return NULL;
1219
1220 return ti;
1221}
1222
1223static long dm_dax_direct_access(struct dax_device *dax_dev, pgoff_t pgoff,
1224 long nr_pages, enum dax_access_mode mode, void **kaddr,
1225 pfn_t *pfn)
1226{
1227 struct mapped_device *md = dax_get_private(dax_dev);
1228 sector_t sector = pgoff * PAGE_SECTORS;
1229 struct dm_target *ti;
1230 long len, ret = -EIO;
1231 int srcu_idx;
1232
1233 ti = dm_dax_get_live_target(md, sector, &srcu_idx);
1234
1235 if (!ti)
1236 goto out;
1237 if (!ti->type->direct_access)
1238 goto out;
1239 len = max_io_len(ti, sector) / PAGE_SECTORS;
1240 if (len < 1)
1241 goto out;
1242 nr_pages = min(len, nr_pages);
1243 ret = ti->type->direct_access(ti, pgoff, nr_pages, mode, kaddr, pfn);
1244
1245 out:
1246 dm_put_live_table(md, srcu_idx);
1247
1248 return ret;
1249}
1250
1251static int dm_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
1252 size_t nr_pages)
1253{
1254 struct mapped_device *md = dax_get_private(dax_dev);
1255 sector_t sector = pgoff * PAGE_SECTORS;
1256 struct dm_target *ti;
1257 int ret = -EIO;
1258 int srcu_idx;
1259
1260 ti = dm_dax_get_live_target(md, sector, &srcu_idx);
1261
1262 if (!ti)
1263 goto out;
1264 if (WARN_ON(!ti->type->dax_zero_page_range)) {
1265 /*
1266 * ->zero_page_range() is mandatory dax operation. If we are
1267 * here, something is wrong.
1268 */
1269 goto out;
1270 }
1271 ret = ti->type->dax_zero_page_range(ti, pgoff, nr_pages);
1272 out:
1273 dm_put_live_table(md, srcu_idx);
1274
1275 return ret;
1276}
1277
1278static size_t dm_dax_recovery_write(struct dax_device *dax_dev, pgoff_t pgoff,
1279 void *addr, size_t bytes, struct iov_iter *i)
1280{
1281 struct mapped_device *md = dax_get_private(dax_dev);
1282 sector_t sector = pgoff * PAGE_SECTORS;
1283 struct dm_target *ti;
1284 int srcu_idx;
1285 long ret = 0;
1286
1287 ti = dm_dax_get_live_target(md, sector, &srcu_idx);
1288 if (!ti || !ti->type->dax_recovery_write)
1289 goto out;
1290
1291 ret = ti->type->dax_recovery_write(ti, pgoff, addr, bytes, i);
1292out:
1293 dm_put_live_table(md, srcu_idx);
1294 return ret;
1295}
1296
1297/*
1298 * A target may call dm_accept_partial_bio only from the map routine. It is
1299 * allowed for all bio types except REQ_PREFLUSH, REQ_OP_ZONE_* zone management
1300 * operations, REQ_OP_ZONE_APPEND (zone append writes) and any bio serviced by
1301 * __send_duplicate_bios().
1302 *
1303 * dm_accept_partial_bio informs the dm that the target only wants to process
1304 * additional n_sectors sectors of the bio and the rest of the data should be
1305 * sent in a next bio.
1306 *
1307 * A diagram that explains the arithmetics:
1308 * +--------------------+---------------+-------+
1309 * | 1 | 2 | 3 |
1310 * +--------------------+---------------+-------+
1311 *
1312 * <-------------- *tio->len_ptr --------------->
1313 * <----- bio_sectors ----->
1314 * <-- n_sectors -->
1315 *
1316 * Region 1 was already iterated over with bio_advance or similar function.
1317 * (it may be empty if the target doesn't use bio_advance)
1318 * Region 2 is the remaining bio size that the target wants to process.
1319 * (it may be empty if region 1 is non-empty, although there is no reason
1320 * to make it empty)
1321 * The target requires that region 3 is to be sent in the next bio.
1322 *
1323 * If the target wants to receive multiple copies of the bio (via num_*bios, etc),
1324 * the partially processed part (the sum of regions 1+2) must be the same for all
1325 * copies of the bio.
1326 */
1327void dm_accept_partial_bio(struct bio *bio, unsigned int n_sectors)
1328{
1329 struct dm_target_io *tio = clone_to_tio(bio);
1330 struct dm_io *io = tio->io;
1331 unsigned int bio_sectors = bio_sectors(bio);
1332
1333 BUG_ON(dm_tio_flagged(tio, DM_TIO_IS_DUPLICATE_BIO));
1334 BUG_ON(op_is_zone_mgmt(bio_op(bio)));
1335 BUG_ON(bio_op(bio) == REQ_OP_ZONE_APPEND);
1336 BUG_ON(bio_sectors > *tio->len_ptr);
1337 BUG_ON(n_sectors > bio_sectors);
1338
1339 *tio->len_ptr -= bio_sectors - n_sectors;
1340 bio->bi_iter.bi_size = n_sectors << SECTOR_SHIFT;
1341
1342 /*
1343 * __split_and_process_bio() may have already saved mapped part
1344 * for accounting but it is being reduced so update accordingly.
1345 */
1346 dm_io_set_flag(io, DM_IO_WAS_SPLIT);
1347 io->sectors = n_sectors;
1348 io->sector_offset = bio_sectors(io->orig_bio);
1349}
1350EXPORT_SYMBOL_GPL(dm_accept_partial_bio);
1351
1352/*
1353 * @clone: clone bio that DM core passed to target's .map function
1354 * @tgt_clone: clone of @clone bio that target needs submitted
1355 *
1356 * Targets should use this interface to submit bios they take
1357 * ownership of when returning DM_MAPIO_SUBMITTED.
1358 *
1359 * Target should also enable ti->accounts_remapped_io
1360 */
1361void dm_submit_bio_remap(struct bio *clone, struct bio *tgt_clone)
1362{
1363 struct dm_target_io *tio = clone_to_tio(clone);
1364 struct dm_io *io = tio->io;
1365
1366 /* establish bio that will get submitted */
1367 if (!tgt_clone)
1368 tgt_clone = clone;
1369
1370 /*
1371 * Account io->origin_bio to DM dev on behalf of target
1372 * that took ownership of IO with DM_MAPIO_SUBMITTED.
1373 */
1374 dm_start_io_acct(io, clone);
1375
1376 trace_block_bio_remap(tgt_clone, disk_devt(io->md->disk),
1377 tio->old_sector);
1378 submit_bio_noacct(tgt_clone);
1379}
1380EXPORT_SYMBOL_GPL(dm_submit_bio_remap);
1381
1382static noinline void __set_swap_bios_limit(struct mapped_device *md, int latch)
1383{
1384 mutex_lock(&md->swap_bios_lock);
1385 while (latch < md->swap_bios) {
1386 cond_resched();
1387 down(&md->swap_bios_semaphore);
1388 md->swap_bios--;
1389 }
1390 while (latch > md->swap_bios) {
1391 cond_resched();
1392 up(&md->swap_bios_semaphore);
1393 md->swap_bios++;
1394 }
1395 mutex_unlock(&md->swap_bios_lock);
1396}
1397
1398static void __map_bio(struct bio *clone)
1399{
1400 struct dm_target_io *tio = clone_to_tio(clone);
1401 struct dm_target *ti = tio->ti;
1402 struct dm_io *io = tio->io;
1403 struct mapped_device *md = io->md;
1404 int r;
1405
1406 clone->bi_end_io = clone_endio;
1407
1408 /*
1409 * Map the clone.
1410 */
1411 tio->old_sector = clone->bi_iter.bi_sector;
1412
1413 if (static_branch_unlikely(&swap_bios_enabled) &&
1414 unlikely(swap_bios_limit(ti, clone))) {
1415 int latch = get_swap_bios();
1416
1417 if (unlikely(latch != md->swap_bios))
1418 __set_swap_bios_limit(md, latch);
1419 down(&md->swap_bios_semaphore);
1420 }
1421
1422 if (static_branch_unlikely(&zoned_enabled)) {
1423 /*
1424 * Check if the IO needs a special mapping due to zone append
1425 * emulation on zoned target. In this case, dm_zone_map_bio()
1426 * calls the target map operation.
1427 */
1428 if (unlikely(dm_emulate_zone_append(md)))
1429 r = dm_zone_map_bio(tio);
1430 else
1431 goto do_map;
1432 } else {
1433do_map:
1434 if (likely(ti->type->map == linear_map))
1435 r = linear_map(ti, clone);
1436 else if (ti->type->map == stripe_map)
1437 r = stripe_map(ti, clone);
1438 else
1439 r = ti->type->map(ti, clone);
1440 }
1441
1442 switch (r) {
1443 case DM_MAPIO_SUBMITTED:
1444 /* target has assumed ownership of this io */
1445 if (!ti->accounts_remapped_io)
1446 dm_start_io_acct(io, clone);
1447 break;
1448 case DM_MAPIO_REMAPPED:
1449 dm_submit_bio_remap(clone, NULL);
1450 break;
1451 case DM_MAPIO_KILL:
1452 case DM_MAPIO_REQUEUE:
1453 if (static_branch_unlikely(&swap_bios_enabled) &&
1454 unlikely(swap_bios_limit(ti, clone)))
1455 up(&md->swap_bios_semaphore);
1456 free_tio(clone);
1457 if (r == DM_MAPIO_KILL)
1458 dm_io_dec_pending(io, BLK_STS_IOERR);
1459 else
1460 dm_io_dec_pending(io, BLK_STS_DM_REQUEUE);
1461 break;
1462 default:
1463 DMCRIT("unimplemented target map return value: %d", r);
1464 BUG();
1465 }
1466}
1467
1468static void setup_split_accounting(struct clone_info *ci, unsigned int len)
1469{
1470 struct dm_io *io = ci->io;
1471
1472 if (ci->sector_count > len) {
1473 /*
1474 * Split needed, save the mapped part for accounting.
1475 * NOTE: dm_accept_partial_bio() will update accordingly.
1476 */
1477 dm_io_set_flag(io, DM_IO_WAS_SPLIT);
1478 io->sectors = len;
1479 io->sector_offset = bio_sectors(ci->bio);
1480 }
1481}
1482
1483static void alloc_multiple_bios(struct bio_list *blist, struct clone_info *ci,
1484 struct dm_target *ti, unsigned int num_bios,
1485 unsigned *len, gfp_t gfp_flag)
1486{
1487 struct bio *bio;
1488 int try = (gfp_flag & GFP_NOWAIT) ? 0 : 1;
1489
1490 for (; try < 2; try++) {
1491 int bio_nr;
1492
1493 if (try && num_bios > 1)
1494 mutex_lock(&ci->io->md->table_devices_lock);
1495 for (bio_nr = 0; bio_nr < num_bios; bio_nr++) {
1496 bio = alloc_tio(ci, ti, bio_nr, len,
1497 try ? GFP_NOIO : GFP_NOWAIT);
1498 if (!bio)
1499 break;
1500
1501 bio_list_add(blist, bio);
1502 }
1503 if (try && num_bios > 1)
1504 mutex_unlock(&ci->io->md->table_devices_lock);
1505 if (bio_nr == num_bios)
1506 return;
1507
1508 while ((bio = bio_list_pop(blist)))
1509 free_tio(bio);
1510 }
1511}
1512
1513static unsigned int __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
1514 unsigned int num_bios, unsigned int *len,
1515 gfp_t gfp_flag)
1516{
1517 struct bio_list blist = BIO_EMPTY_LIST;
1518 struct bio *clone;
1519 unsigned int ret = 0;
1520
1521 if (WARN_ON_ONCE(num_bios == 0)) /* num_bios = 0 is a bug in caller */
1522 return 0;
1523
1524 /* dm_accept_partial_bio() is not supported with shared tio->len_ptr */
1525 if (len)
1526 setup_split_accounting(ci, *len);
1527
1528 /*
1529 * Using alloc_multiple_bios(), even if num_bios is 1, to consistently
1530 * support allocating using GFP_NOWAIT with GFP_NOIO fallback.
1531 */
1532 alloc_multiple_bios(&blist, ci, ti, num_bios, len, gfp_flag);
1533 while ((clone = bio_list_pop(&blist))) {
1534 if (num_bios > 1)
1535 dm_tio_set_flag(clone_to_tio(clone), DM_TIO_IS_DUPLICATE_BIO);
1536 __map_bio(clone);
1537 ret += 1;
1538 }
1539
1540 return ret;
1541}
1542
1543static void __send_empty_flush(struct clone_info *ci)
1544{
1545 struct dm_table *t = ci->map;
1546 struct bio flush_bio;
1547
1548 /*
1549 * Use an on-stack bio for this, it's safe since we don't
1550 * need to reference it after submit. It's just used as
1551 * the basis for the clone(s).
1552 */
1553 bio_init(&flush_bio, ci->io->md->disk->part0, NULL, 0,
1554 REQ_OP_WRITE | REQ_PREFLUSH | REQ_SYNC);
1555
1556 ci->bio = &flush_bio;
1557 ci->sector_count = 0;
1558 ci->io->tio.clone.bi_iter.bi_size = 0;
1559
1560 for (unsigned int i = 0; i < t->num_targets; i++) {
1561 unsigned int bios;
1562 struct dm_target *ti = dm_table_get_target(t, i);
1563
1564 if (unlikely(ti->num_flush_bios == 0))
1565 continue;
1566
1567 atomic_add(ti->num_flush_bios, &ci->io->io_count);
1568 bios = __send_duplicate_bios(ci, ti, ti->num_flush_bios,
1569 NULL, GFP_NOWAIT);
1570 atomic_sub(ti->num_flush_bios - bios, &ci->io->io_count);
1571 }
1572
1573 /*
1574 * alloc_io() takes one extra reference for submission, so the
1575 * reference won't reach 0 without the following subtraction
1576 */
1577 atomic_sub(1, &ci->io->io_count);
1578
1579 bio_uninit(ci->bio);
1580}
1581
1582static void __send_abnormal_io(struct clone_info *ci, struct dm_target *ti,
1583 unsigned int num_bios, unsigned int max_granularity,
1584 unsigned int max_sectors)
1585{
1586 unsigned int len, bios;
1587
1588 len = min_t(sector_t, ci->sector_count,
1589 __max_io_len(ti, ci->sector, max_granularity, max_sectors));
1590
1591 atomic_add(num_bios, &ci->io->io_count);
1592 bios = __send_duplicate_bios(ci, ti, num_bios, &len, GFP_NOIO);
1593 /*
1594 * alloc_io() takes one extra reference for submission, so the
1595 * reference won't reach 0 without the following (+1) subtraction
1596 */
1597 atomic_sub(num_bios - bios + 1, &ci->io->io_count);
1598
1599 ci->sector += len;
1600 ci->sector_count -= len;
1601}
1602
1603static bool is_abnormal_io(struct bio *bio)
1604{
1605 enum req_op op = bio_op(bio);
1606
1607 if (op != REQ_OP_READ && op != REQ_OP_WRITE && op != REQ_OP_FLUSH) {
1608 switch (op) {
1609 case REQ_OP_DISCARD:
1610 case REQ_OP_SECURE_ERASE:
1611 case REQ_OP_WRITE_ZEROES:
1612 return true;
1613 default:
1614 break;
1615 }
1616 }
1617
1618 return false;
1619}
1620
1621static blk_status_t __process_abnormal_io(struct clone_info *ci,
1622 struct dm_target *ti)
1623{
1624 unsigned int num_bios = 0;
1625 unsigned int max_granularity = 0;
1626 unsigned int max_sectors = 0;
1627 struct queue_limits *limits = dm_get_queue_limits(ti->table->md);
1628
1629 switch (bio_op(ci->bio)) {
1630 case REQ_OP_DISCARD:
1631 num_bios = ti->num_discard_bios;
1632 max_sectors = limits->max_discard_sectors;
1633 if (ti->max_discard_granularity)
1634 max_granularity = max_sectors;
1635 break;
1636 case REQ_OP_SECURE_ERASE:
1637 num_bios = ti->num_secure_erase_bios;
1638 max_sectors = limits->max_secure_erase_sectors;
1639 if (ti->max_secure_erase_granularity)
1640 max_granularity = max_sectors;
1641 break;
1642 case REQ_OP_WRITE_ZEROES:
1643 num_bios = ti->num_write_zeroes_bios;
1644 max_sectors = limits->max_write_zeroes_sectors;
1645 if (ti->max_write_zeroes_granularity)
1646 max_granularity = max_sectors;
1647 break;
1648 default:
1649 break;
1650 }
1651
1652 /*
1653 * Even though the device advertised support for this type of
1654 * request, that does not mean every target supports it, and
1655 * reconfiguration might also have changed that since the
1656 * check was performed.
1657 */
1658 if (unlikely(!num_bios))
1659 return BLK_STS_NOTSUPP;
1660
1661 __send_abnormal_io(ci, ti, num_bios, max_granularity, max_sectors);
1662
1663 return BLK_STS_OK;
1664}
1665
1666/*
1667 * Reuse ->bi_private as dm_io list head for storing all dm_io instances
1668 * associated with this bio, and this bio's bi_private needs to be
1669 * stored in dm_io->data before the reuse.
1670 *
1671 * bio->bi_private is owned by fs or upper layer, so block layer won't
1672 * touch it after splitting. Meantime it won't be changed by anyone after
1673 * bio is submitted. So this reuse is safe.
1674 */
1675static inline struct dm_io **dm_poll_list_head(struct bio *bio)
1676{
1677 return (struct dm_io **)&bio->bi_private;
1678}
1679
1680static void dm_queue_poll_io(struct bio *bio, struct dm_io *io)
1681{
1682 struct dm_io **head = dm_poll_list_head(bio);
1683
1684 if (!(bio->bi_opf & REQ_DM_POLL_LIST)) {
1685 bio->bi_opf |= REQ_DM_POLL_LIST;
1686 /*
1687 * Save .bi_private into dm_io, so that we can reuse
1688 * .bi_private as dm_io list head for storing dm_io list
1689 */
1690 io->data = bio->bi_private;
1691
1692 /* tell block layer to poll for completion */
1693 bio->bi_cookie = ~BLK_QC_T_NONE;
1694
1695 io->next = NULL;
1696 } else {
1697 /*
1698 * bio recursed due to split, reuse original poll list,
1699 * and save bio->bi_private too.
1700 */
1701 io->data = (*head)->data;
1702 io->next = *head;
1703 }
1704
1705 *head = io;
1706}
1707
1708/*
1709 * Select the correct strategy for processing a non-flush bio.
1710 */
1711static blk_status_t __split_and_process_bio(struct clone_info *ci)
1712{
1713 struct bio *clone;
1714 struct dm_target *ti;
1715 unsigned int len;
1716
1717 ti = dm_table_find_target(ci->map, ci->sector);
1718 if (unlikely(!ti))
1719 return BLK_STS_IOERR;
1720
1721 if (unlikely(ci->is_abnormal_io))
1722 return __process_abnormal_io(ci, ti);
1723
1724 /*
1725 * Only support bio polling for normal IO, and the target io is
1726 * exactly inside the dm_io instance (verified in dm_poll_dm_io)
1727 */
1728 ci->submit_as_polled = !!(ci->bio->bi_opf & REQ_POLLED);
1729
1730 len = min_t(sector_t, max_io_len(ti, ci->sector), ci->sector_count);
1731 setup_split_accounting(ci, len);
1732
1733 if (unlikely(ci->bio->bi_opf & REQ_NOWAIT)) {
1734 if (unlikely(!dm_target_supports_nowait(ti->type)))
1735 return BLK_STS_NOTSUPP;
1736
1737 clone = alloc_tio(ci, ti, 0, &len, GFP_NOWAIT);
1738 if (unlikely(!clone))
1739 return BLK_STS_AGAIN;
1740 } else {
1741 clone = alloc_tio(ci, ti, 0, &len, GFP_NOIO);
1742 }
1743 __map_bio(clone);
1744
1745 ci->sector += len;
1746 ci->sector_count -= len;
1747
1748 return BLK_STS_OK;
1749}
1750
1751static void init_clone_info(struct clone_info *ci, struct dm_io *io,
1752 struct dm_table *map, struct bio *bio, bool is_abnormal)
1753{
1754 ci->map = map;
1755 ci->io = io;
1756 ci->bio = bio;
1757 ci->is_abnormal_io = is_abnormal;
1758 ci->submit_as_polled = false;
1759 ci->sector = bio->bi_iter.bi_sector;
1760 ci->sector_count = bio_sectors(bio);
1761
1762 /* Shouldn't happen but sector_count was being set to 0 so... */
1763 if (static_branch_unlikely(&zoned_enabled) &&
1764 WARN_ON_ONCE(op_is_zone_mgmt(bio_op(bio)) && ci->sector_count))
1765 ci->sector_count = 0;
1766}
1767
1768/*
1769 * Entry point to split a bio into clones and submit them to the targets.
1770 */
1771static void dm_split_and_process_bio(struct mapped_device *md,
1772 struct dm_table *map, struct bio *bio)
1773{
1774 struct clone_info ci;
1775 struct dm_io *io;
1776 blk_status_t error = BLK_STS_OK;
1777 bool is_abnormal;
1778
1779 is_abnormal = is_abnormal_io(bio);
1780 if (unlikely(is_abnormal)) {
1781 /*
1782 * Use bio_split_to_limits() for abnormal IO (e.g. discard, etc)
1783 * otherwise associated queue_limits won't be imposed.
1784 */
1785 bio = bio_split_to_limits(bio);
1786 if (!bio)
1787 return;
1788 }
1789
1790 /* Only support nowait for normal IO */
1791 if (unlikely(bio->bi_opf & REQ_NOWAIT) && !is_abnormal) {
1792 io = alloc_io(md, bio, GFP_NOWAIT);
1793 if (unlikely(!io)) {
1794 /* Unable to do anything without dm_io. */
1795 bio_wouldblock_error(bio);
1796 return;
1797 }
1798 } else {
1799 io = alloc_io(md, bio, GFP_NOIO);
1800 }
1801 init_clone_info(&ci, io, map, bio, is_abnormal);
1802
1803 if (bio->bi_opf & REQ_PREFLUSH) {
1804 __send_empty_flush(&ci);
1805 /* dm_io_complete submits any data associated with flush */
1806 goto out;
1807 }
1808
1809 error = __split_and_process_bio(&ci);
1810 if (error || !ci.sector_count)
1811 goto out;
1812 /*
1813 * Remainder must be passed to submit_bio_noacct() so it gets handled
1814 * *after* bios already submitted have been completely processed.
1815 */
1816 bio_trim(bio, io->sectors, ci.sector_count);
1817 trace_block_split(bio, bio->bi_iter.bi_sector);
1818 bio_inc_remaining(bio);
1819 submit_bio_noacct(bio);
1820out:
1821 /*
1822 * Drop the extra reference count for non-POLLED bio, and hold one
1823 * reference for POLLED bio, which will be released in dm_poll_bio
1824 *
1825 * Add every dm_io instance into the dm_io list head which is stored
1826 * in bio->bi_private, so that dm_poll_bio can poll them all.
1827 */
1828 if (error || !ci.submit_as_polled) {
1829 /*
1830 * In case of submission failure, the extra reference for
1831 * submitting io isn't consumed yet
1832 */
1833 if (error)
1834 atomic_dec(&io->io_count);
1835 dm_io_dec_pending(io, error);
1836 } else
1837 dm_queue_poll_io(bio, io);
1838}
1839
1840static void dm_submit_bio(struct bio *bio)
1841{
1842 struct mapped_device *md = bio->bi_bdev->bd_disk->private_data;
1843 int srcu_idx;
1844 struct dm_table *map;
1845
1846 map = dm_get_live_table(md, &srcu_idx);
1847
1848 /* If suspended, or map not yet available, queue this IO for later */
1849 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) ||
1850 unlikely(!map)) {
1851 if (bio->bi_opf & REQ_NOWAIT)
1852 bio_wouldblock_error(bio);
1853 else if (bio->bi_opf & REQ_RAHEAD)
1854 bio_io_error(bio);
1855 else
1856 queue_io(md, bio);
1857 goto out;
1858 }
1859
1860 dm_split_and_process_bio(md, map, bio);
1861out:
1862 dm_put_live_table(md, srcu_idx);
1863}
1864
1865static bool dm_poll_dm_io(struct dm_io *io, struct io_comp_batch *iob,
1866 unsigned int flags)
1867{
1868 WARN_ON_ONCE(!dm_tio_is_normal(&io->tio));
1869
1870 /* don't poll if the mapped io is done */
1871 if (atomic_read(&io->io_count) > 1)
1872 bio_poll(&io->tio.clone, iob, flags);
1873
1874 /* bio_poll holds the last reference */
1875 return atomic_read(&io->io_count) == 1;
1876}
1877
1878static int dm_poll_bio(struct bio *bio, struct io_comp_batch *iob,
1879 unsigned int flags)
1880{
1881 struct dm_io **head = dm_poll_list_head(bio);
1882 struct dm_io *list = *head;
1883 struct dm_io *tmp = NULL;
1884 struct dm_io *curr, *next;
1885
1886 /* Only poll normal bio which was marked as REQ_DM_POLL_LIST */
1887 if (!(bio->bi_opf & REQ_DM_POLL_LIST))
1888 return 0;
1889
1890 WARN_ON_ONCE(!list);
1891
1892 /*
1893 * Restore .bi_private before possibly completing dm_io.
1894 *
1895 * bio_poll() is only possible once @bio has been completely
1896 * submitted via submit_bio_noacct()'s depth-first submission.
1897 * So there is no dm_queue_poll_io() race associated with
1898 * clearing REQ_DM_POLL_LIST here.
1899 */
1900 bio->bi_opf &= ~REQ_DM_POLL_LIST;
1901 bio->bi_private = list->data;
1902
1903 for (curr = list, next = curr->next; curr; curr = next, next =
1904 curr ? curr->next : NULL) {
1905 if (dm_poll_dm_io(curr, iob, flags)) {
1906 /*
1907 * clone_endio() has already occurred, so no
1908 * error handling is needed here.
1909 */
1910 __dm_io_dec_pending(curr);
1911 } else {
1912 curr->next = tmp;
1913 tmp = curr;
1914 }
1915 }
1916
1917 /* Not done? */
1918 if (tmp) {
1919 bio->bi_opf |= REQ_DM_POLL_LIST;
1920 /* Reset bio->bi_private to dm_io list head */
1921 *head = tmp;
1922 return 0;
1923 }
1924 return 1;
1925}
1926
1927/*
1928 *---------------------------------------------------------------
1929 * An IDR is used to keep track of allocated minor numbers.
1930 *---------------------------------------------------------------
1931 */
1932static void free_minor(int minor)
1933{
1934 spin_lock(&_minor_lock);
1935 idr_remove(&_minor_idr, minor);
1936 spin_unlock(&_minor_lock);
1937}
1938
1939/*
1940 * See if the device with a specific minor # is free.
1941 */
1942static int specific_minor(int minor)
1943{
1944 int r;
1945
1946 if (minor >= (1 << MINORBITS))
1947 return -EINVAL;
1948
1949 idr_preload(GFP_KERNEL);
1950 spin_lock(&_minor_lock);
1951
1952 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
1953
1954 spin_unlock(&_minor_lock);
1955 idr_preload_end();
1956 if (r < 0)
1957 return r == -ENOSPC ? -EBUSY : r;
1958 return 0;
1959}
1960
1961static int next_free_minor(int *minor)
1962{
1963 int r;
1964
1965 idr_preload(GFP_KERNEL);
1966 spin_lock(&_minor_lock);
1967
1968 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
1969
1970 spin_unlock(&_minor_lock);
1971 idr_preload_end();
1972 if (r < 0)
1973 return r;
1974 *minor = r;
1975 return 0;
1976}
1977
1978static const struct block_device_operations dm_blk_dops;
1979static const struct block_device_operations dm_rq_blk_dops;
1980static const struct dax_operations dm_dax_ops;
1981
1982static void dm_wq_work(struct work_struct *work);
1983
1984#ifdef CONFIG_BLK_INLINE_ENCRYPTION
1985static void dm_queue_destroy_crypto_profile(struct request_queue *q)
1986{
1987 dm_destroy_crypto_profile(q->crypto_profile);
1988}
1989
1990#else /* CONFIG_BLK_INLINE_ENCRYPTION */
1991
1992static inline void dm_queue_destroy_crypto_profile(struct request_queue *q)
1993{
1994}
1995#endif /* !CONFIG_BLK_INLINE_ENCRYPTION */
1996
1997static void cleanup_mapped_device(struct mapped_device *md)
1998{
1999 if (md->wq)
2000 destroy_workqueue(md->wq);
2001 dm_free_md_mempools(md->mempools);
2002
2003 if (md->dax_dev) {
2004 dax_remove_host(md->disk);
2005 kill_dax(md->dax_dev);
2006 put_dax(md->dax_dev);
2007 md->dax_dev = NULL;
2008 }
2009
2010 dm_cleanup_zoned_dev(md);
2011 if (md->disk) {
2012 spin_lock(&_minor_lock);
2013 md->disk->private_data = NULL;
2014 spin_unlock(&_minor_lock);
2015 if (dm_get_md_type(md) != DM_TYPE_NONE) {
2016 struct table_device *td;
2017
2018 dm_sysfs_exit(md);
2019 list_for_each_entry(td, &md->table_devices, list) {
2020 bd_unlink_disk_holder(td->dm_dev.bdev,
2021 md->disk);
2022 }
2023
2024 /*
2025 * Hold lock to make sure del_gendisk() won't concurrent
2026 * with open/close_table_device().
2027 */
2028 mutex_lock(&md->table_devices_lock);
2029 del_gendisk(md->disk);
2030 mutex_unlock(&md->table_devices_lock);
2031 }
2032 dm_queue_destroy_crypto_profile(md->queue);
2033 put_disk(md->disk);
2034 }
2035
2036 if (md->pending_io) {
2037 free_percpu(md->pending_io);
2038 md->pending_io = NULL;
2039 }
2040
2041 cleanup_srcu_struct(&md->io_barrier);
2042
2043 mutex_destroy(&md->suspend_lock);
2044 mutex_destroy(&md->type_lock);
2045 mutex_destroy(&md->table_devices_lock);
2046 mutex_destroy(&md->swap_bios_lock);
2047
2048 dm_mq_cleanup_mapped_device(md);
2049}
2050
2051/*
2052 * Allocate and initialise a blank device with a given minor.
2053 */
2054static struct mapped_device *alloc_dev(int minor)
2055{
2056 int r, numa_node_id = dm_get_numa_node();
2057 struct mapped_device *md;
2058 void *old_md;
2059
2060 md = kvzalloc_node(sizeof(*md), GFP_KERNEL, numa_node_id);
2061 if (!md) {
2062 DMERR("unable to allocate device, out of memory.");
2063 return NULL;
2064 }
2065
2066 if (!try_module_get(THIS_MODULE))
2067 goto bad_module_get;
2068
2069 /* get a minor number for the dev */
2070 if (minor == DM_ANY_MINOR)
2071 r = next_free_minor(&minor);
2072 else
2073 r = specific_minor(minor);
2074 if (r < 0)
2075 goto bad_minor;
2076
2077 r = init_srcu_struct(&md->io_barrier);
2078 if (r < 0)
2079 goto bad_io_barrier;
2080
2081 md->numa_node_id = numa_node_id;
2082 md->init_tio_pdu = false;
2083 md->type = DM_TYPE_NONE;
2084 mutex_init(&md->suspend_lock);
2085 mutex_init(&md->type_lock);
2086 mutex_init(&md->table_devices_lock);
2087 spin_lock_init(&md->deferred_lock);
2088 atomic_set(&md->holders, 1);
2089 atomic_set(&md->open_count, 0);
2090 atomic_set(&md->event_nr, 0);
2091 atomic_set(&md->uevent_seq, 0);
2092 INIT_LIST_HEAD(&md->uevent_list);
2093 INIT_LIST_HEAD(&md->table_devices);
2094 spin_lock_init(&md->uevent_lock);
2095
2096 /*
2097 * default to bio-based until DM table is loaded and md->type
2098 * established. If request-based table is loaded: blk-mq will
2099 * override accordingly.
2100 */
2101 md->disk = blk_alloc_disk(md->numa_node_id);
2102 if (!md->disk)
2103 goto bad;
2104 md->queue = md->disk->queue;
2105
2106 init_waitqueue_head(&md->wait);
2107 INIT_WORK(&md->work, dm_wq_work);
2108 INIT_WORK(&md->requeue_work, dm_wq_requeue_work);
2109 init_waitqueue_head(&md->eventq);
2110 init_completion(&md->kobj_holder.completion);
2111
2112 md->requeue_list = NULL;
2113 md->swap_bios = get_swap_bios();
2114 sema_init(&md->swap_bios_semaphore, md->swap_bios);
2115 mutex_init(&md->swap_bios_lock);
2116
2117 md->disk->major = _major;
2118 md->disk->first_minor = minor;
2119 md->disk->minors = 1;
2120 md->disk->flags |= GENHD_FL_NO_PART;
2121 md->disk->fops = &dm_blk_dops;
2122 md->disk->private_data = md;
2123 sprintf(md->disk->disk_name, "dm-%d", minor);
2124
2125 if (IS_ENABLED(CONFIG_FS_DAX)) {
2126 md->dax_dev = alloc_dax(md, &dm_dax_ops);
2127 if (IS_ERR(md->dax_dev)) {
2128 md->dax_dev = NULL;
2129 goto bad;
2130 }
2131 set_dax_nocache(md->dax_dev);
2132 set_dax_nomc(md->dax_dev);
2133 if (dax_add_host(md->dax_dev, md->disk))
2134 goto bad;
2135 }
2136
2137 format_dev_t(md->name, MKDEV(_major, minor));
2138
2139 md->wq = alloc_workqueue("kdmflush/%s", WQ_MEM_RECLAIM, 0, md->name);
2140 if (!md->wq)
2141 goto bad;
2142
2143 md->pending_io = alloc_percpu(unsigned long);
2144 if (!md->pending_io)
2145 goto bad;
2146
2147 r = dm_stats_init(&md->stats);
2148 if (r < 0)
2149 goto bad;
2150
2151 /* Populate the mapping, nobody knows we exist yet */
2152 spin_lock(&_minor_lock);
2153 old_md = idr_replace(&_minor_idr, md, minor);
2154 spin_unlock(&_minor_lock);
2155
2156 BUG_ON(old_md != MINOR_ALLOCED);
2157
2158 return md;
2159
2160bad:
2161 cleanup_mapped_device(md);
2162bad_io_barrier:
2163 free_minor(minor);
2164bad_minor:
2165 module_put(THIS_MODULE);
2166bad_module_get:
2167 kvfree(md);
2168 return NULL;
2169}
2170
2171static void unlock_fs(struct mapped_device *md);
2172
2173static void free_dev(struct mapped_device *md)
2174{
2175 int minor = MINOR(disk_devt(md->disk));
2176
2177 unlock_fs(md);
2178
2179 cleanup_mapped_device(md);
2180
2181 WARN_ON_ONCE(!list_empty(&md->table_devices));
2182 dm_stats_cleanup(&md->stats);
2183 free_minor(minor);
2184
2185 module_put(THIS_MODULE);
2186 kvfree(md);
2187}
2188
2189/*
2190 * Bind a table to the device.
2191 */
2192static void event_callback(void *context)
2193{
2194 unsigned long flags;
2195 LIST_HEAD(uevents);
2196 struct mapped_device *md = context;
2197
2198 spin_lock_irqsave(&md->uevent_lock, flags);
2199 list_splice_init(&md->uevent_list, &uevents);
2200 spin_unlock_irqrestore(&md->uevent_lock, flags);
2201
2202 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
2203
2204 atomic_inc(&md->event_nr);
2205 wake_up(&md->eventq);
2206 dm_issue_global_event();
2207}
2208
2209/*
2210 * Returns old map, which caller must destroy.
2211 */
2212static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
2213 struct queue_limits *limits)
2214{
2215 struct dm_table *old_map;
2216 sector_t size;
2217 int ret;
2218
2219 lockdep_assert_held(&md->suspend_lock);
2220
2221 size = dm_table_get_size(t);
2222
2223 /*
2224 * Wipe any geometry if the size of the table changed.
2225 */
2226 if (size != dm_get_size(md))
2227 memset(&md->geometry, 0, sizeof(md->geometry));
2228
2229 set_capacity(md->disk, size);
2230
2231 dm_table_event_callback(t, event_callback, md);
2232
2233 if (dm_table_request_based(t)) {
2234 /*
2235 * Leverage the fact that request-based DM targets are
2236 * immutable singletons - used to optimize dm_mq_queue_rq.
2237 */
2238 md->immutable_target = dm_table_get_immutable_target(t);
2239
2240 /*
2241 * There is no need to reload with request-based dm because the
2242 * size of front_pad doesn't change.
2243 *
2244 * Note for future: If you are to reload bioset, prep-ed
2245 * requests in the queue may refer to bio from the old bioset,
2246 * so you must walk through the queue to unprep.
2247 */
2248 if (!md->mempools) {
2249 md->mempools = t->mempools;
2250 t->mempools = NULL;
2251 }
2252 } else {
2253 /*
2254 * The md may already have mempools that need changing.
2255 * If so, reload bioset because front_pad may have changed
2256 * because a different table was loaded.
2257 */
2258 dm_free_md_mempools(md->mempools);
2259 md->mempools = t->mempools;
2260 t->mempools = NULL;
2261 }
2262
2263 ret = dm_table_set_restrictions(t, md->queue, limits);
2264 if (ret) {
2265 old_map = ERR_PTR(ret);
2266 goto out;
2267 }
2268
2269 old_map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
2270 rcu_assign_pointer(md->map, (void *)t);
2271 md->immutable_target_type = dm_table_get_immutable_target_type(t);
2272
2273 if (old_map)
2274 dm_sync_table(md);
2275out:
2276 return old_map;
2277}
2278
2279/*
2280 * Returns unbound table for the caller to free.
2281 */
2282static struct dm_table *__unbind(struct mapped_device *md)
2283{
2284 struct dm_table *map = rcu_dereference_protected(md->map, 1);
2285
2286 if (!map)
2287 return NULL;
2288
2289 dm_table_event_callback(map, NULL, NULL);
2290 RCU_INIT_POINTER(md->map, NULL);
2291 dm_sync_table(md);
2292
2293 return map;
2294}
2295
2296/*
2297 * Constructor for a new device.
2298 */
2299int dm_create(int minor, struct mapped_device **result)
2300{
2301 struct mapped_device *md;
2302
2303 md = alloc_dev(minor);
2304 if (!md)
2305 return -ENXIO;
2306
2307 dm_ima_reset_data(md);
2308
2309 *result = md;
2310 return 0;
2311}
2312
2313/*
2314 * Functions to manage md->type.
2315 * All are required to hold md->type_lock.
2316 */
2317void dm_lock_md_type(struct mapped_device *md)
2318{
2319 mutex_lock(&md->type_lock);
2320}
2321
2322void dm_unlock_md_type(struct mapped_device *md)
2323{
2324 mutex_unlock(&md->type_lock);
2325}
2326
2327void dm_set_md_type(struct mapped_device *md, enum dm_queue_mode type)
2328{
2329 BUG_ON(!mutex_is_locked(&md->type_lock));
2330 md->type = type;
2331}
2332
2333enum dm_queue_mode dm_get_md_type(struct mapped_device *md)
2334{
2335 return md->type;
2336}
2337
2338struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
2339{
2340 return md->immutable_target_type;
2341}
2342
2343/*
2344 * Setup the DM device's queue based on md's type
2345 */
2346int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
2347{
2348 enum dm_queue_mode type = dm_table_get_type(t);
2349 struct queue_limits limits;
2350 struct table_device *td;
2351 int r;
2352
2353 switch (type) {
2354 case DM_TYPE_REQUEST_BASED:
2355 md->disk->fops = &dm_rq_blk_dops;
2356 r = dm_mq_init_request_queue(md, t);
2357 if (r) {
2358 DMERR("Cannot initialize queue for request-based dm mapped device");
2359 return r;
2360 }
2361 break;
2362 case DM_TYPE_BIO_BASED:
2363 case DM_TYPE_DAX_BIO_BASED:
2364 blk_queue_flag_set(QUEUE_FLAG_IO_STAT, md->queue);
2365 break;
2366 case DM_TYPE_NONE:
2367 WARN_ON_ONCE(true);
2368 break;
2369 }
2370
2371 r = dm_calculate_queue_limits(t, &limits);
2372 if (r) {
2373 DMERR("Cannot calculate initial queue limits");
2374 return r;
2375 }
2376 r = dm_table_set_restrictions(t, md->queue, &limits);
2377 if (r)
2378 return r;
2379
2380 /*
2381 * Hold lock to make sure add_disk() and del_gendisk() won't concurrent
2382 * with open_table_device() and close_table_device().
2383 */
2384 mutex_lock(&md->table_devices_lock);
2385 r = add_disk(md->disk);
2386 mutex_unlock(&md->table_devices_lock);
2387 if (r)
2388 return r;
2389
2390 /*
2391 * Register the holder relationship for devices added before the disk
2392 * was live.
2393 */
2394 list_for_each_entry(td, &md->table_devices, list) {
2395 r = bd_link_disk_holder(td->dm_dev.bdev, md->disk);
2396 if (r)
2397 goto out_undo_holders;
2398 }
2399
2400 r = dm_sysfs_init(md);
2401 if (r)
2402 goto out_undo_holders;
2403
2404 md->type = type;
2405 return 0;
2406
2407out_undo_holders:
2408 list_for_each_entry_continue_reverse(td, &md->table_devices, list)
2409 bd_unlink_disk_holder(td->dm_dev.bdev, md->disk);
2410 mutex_lock(&md->table_devices_lock);
2411 del_gendisk(md->disk);
2412 mutex_unlock(&md->table_devices_lock);
2413 return r;
2414}
2415
2416struct mapped_device *dm_get_md(dev_t dev)
2417{
2418 struct mapped_device *md;
2419 unsigned int minor = MINOR(dev);
2420
2421 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2422 return NULL;
2423
2424 spin_lock(&_minor_lock);
2425
2426 md = idr_find(&_minor_idr, minor);
2427 if (!md || md == MINOR_ALLOCED || (MINOR(disk_devt(dm_disk(md))) != minor) ||
2428 test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
2429 md = NULL;
2430 goto out;
2431 }
2432 dm_get(md);
2433out:
2434 spin_unlock(&_minor_lock);
2435
2436 return md;
2437}
2438EXPORT_SYMBOL_GPL(dm_get_md);
2439
2440void *dm_get_mdptr(struct mapped_device *md)
2441{
2442 return md->interface_ptr;
2443}
2444
2445void dm_set_mdptr(struct mapped_device *md, void *ptr)
2446{
2447 md->interface_ptr = ptr;
2448}
2449
2450void dm_get(struct mapped_device *md)
2451{
2452 atomic_inc(&md->holders);
2453 BUG_ON(test_bit(DMF_FREEING, &md->flags));
2454}
2455
2456int dm_hold(struct mapped_device *md)
2457{
2458 spin_lock(&_minor_lock);
2459 if (test_bit(DMF_FREEING, &md->flags)) {
2460 spin_unlock(&_minor_lock);
2461 return -EBUSY;
2462 }
2463 dm_get(md);
2464 spin_unlock(&_minor_lock);
2465 return 0;
2466}
2467EXPORT_SYMBOL_GPL(dm_hold);
2468
2469const char *dm_device_name(struct mapped_device *md)
2470{
2471 return md->name;
2472}
2473EXPORT_SYMBOL_GPL(dm_device_name);
2474
2475static void __dm_destroy(struct mapped_device *md, bool wait)
2476{
2477 struct dm_table *map;
2478 int srcu_idx;
2479
2480 might_sleep();
2481
2482 spin_lock(&_minor_lock);
2483 idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
2484 set_bit(DMF_FREEING, &md->flags);
2485 spin_unlock(&_minor_lock);
2486
2487 blk_mark_disk_dead(md->disk);
2488
2489 /*
2490 * Take suspend_lock so that presuspend and postsuspend methods
2491 * do not race with internal suspend.
2492 */
2493 mutex_lock(&md->suspend_lock);
2494 map = dm_get_live_table(md, &srcu_idx);
2495 if (!dm_suspended_md(md)) {
2496 dm_table_presuspend_targets(map);
2497 set_bit(DMF_SUSPENDED, &md->flags);
2498 set_bit(DMF_POST_SUSPENDING, &md->flags);
2499 dm_table_postsuspend_targets(map);
2500 }
2501 /* dm_put_live_table must be before fsleep, otherwise deadlock is possible */
2502 dm_put_live_table(md, srcu_idx);
2503 mutex_unlock(&md->suspend_lock);
2504
2505 /*
2506 * Rare, but there may be I/O requests still going to complete,
2507 * for example. Wait for all references to disappear.
2508 * No one should increment the reference count of the mapped_device,
2509 * after the mapped_device state becomes DMF_FREEING.
2510 */
2511 if (wait)
2512 while (atomic_read(&md->holders))
2513 fsleep(1000);
2514 else if (atomic_read(&md->holders))
2515 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2516 dm_device_name(md), atomic_read(&md->holders));
2517
2518 dm_table_destroy(__unbind(md));
2519 free_dev(md);
2520}
2521
2522void dm_destroy(struct mapped_device *md)
2523{
2524 __dm_destroy(md, true);
2525}
2526
2527void dm_destroy_immediate(struct mapped_device *md)
2528{
2529 __dm_destroy(md, false);
2530}
2531
2532void dm_put(struct mapped_device *md)
2533{
2534 atomic_dec(&md->holders);
2535}
2536EXPORT_SYMBOL_GPL(dm_put);
2537
2538static bool dm_in_flight_bios(struct mapped_device *md)
2539{
2540 int cpu;
2541 unsigned long sum = 0;
2542
2543 for_each_possible_cpu(cpu)
2544 sum += *per_cpu_ptr(md->pending_io, cpu);
2545
2546 return sum != 0;
2547}
2548
2549static int dm_wait_for_bios_completion(struct mapped_device *md, unsigned int task_state)
2550{
2551 int r = 0;
2552 DEFINE_WAIT(wait);
2553
2554 while (true) {
2555 prepare_to_wait(&md->wait, &wait, task_state);
2556
2557 if (!dm_in_flight_bios(md))
2558 break;
2559
2560 if (signal_pending_state(task_state, current)) {
2561 r = -EINTR;
2562 break;
2563 }
2564
2565 io_schedule();
2566 }
2567 finish_wait(&md->wait, &wait);
2568
2569 smp_rmb();
2570
2571 return r;
2572}
2573
2574static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_state)
2575{
2576 int r = 0;
2577
2578 if (!queue_is_mq(md->queue))
2579 return dm_wait_for_bios_completion(md, task_state);
2580
2581 while (true) {
2582 if (!blk_mq_queue_inflight(md->queue))
2583 break;
2584
2585 if (signal_pending_state(task_state, current)) {
2586 r = -EINTR;
2587 break;
2588 }
2589
2590 fsleep(5000);
2591 }
2592
2593 return r;
2594}
2595
2596/*
2597 * Process the deferred bios
2598 */
2599static void dm_wq_work(struct work_struct *work)
2600{
2601 struct mapped_device *md = container_of(work, struct mapped_device, work);
2602 struct bio *bio;
2603
2604 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2605 spin_lock_irq(&md->deferred_lock);
2606 bio = bio_list_pop(&md->deferred);
2607 spin_unlock_irq(&md->deferred_lock);
2608
2609 if (!bio)
2610 break;
2611
2612 submit_bio_noacct(bio);
2613 cond_resched();
2614 }
2615}
2616
2617static void dm_queue_flush(struct mapped_device *md)
2618{
2619 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2620 smp_mb__after_atomic();
2621 queue_work(md->wq, &md->work);
2622}
2623
2624/*
2625 * Swap in a new table, returning the old one for the caller to destroy.
2626 */
2627struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
2628{
2629 struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
2630 struct queue_limits limits;
2631 int r;
2632
2633 mutex_lock(&md->suspend_lock);
2634
2635 /* device must be suspended */
2636 if (!dm_suspended_md(md))
2637 goto out;
2638
2639 /*
2640 * If the new table has no data devices, retain the existing limits.
2641 * This helps multipath with queue_if_no_path if all paths disappear,
2642 * then new I/O is queued based on these limits, and then some paths
2643 * reappear.
2644 */
2645 if (dm_table_has_no_data_devices(table)) {
2646 live_map = dm_get_live_table_fast(md);
2647 if (live_map)
2648 limits = md->queue->limits;
2649 dm_put_live_table_fast(md);
2650 }
2651
2652 if (!live_map) {
2653 r = dm_calculate_queue_limits(table, &limits);
2654 if (r) {
2655 map = ERR_PTR(r);
2656 goto out;
2657 }
2658 }
2659
2660 map = __bind(md, table, &limits);
2661 dm_issue_global_event();
2662
2663out:
2664 mutex_unlock(&md->suspend_lock);
2665 return map;
2666}
2667
2668/*
2669 * Functions to lock and unlock any filesystem running on the
2670 * device.
2671 */
2672static int lock_fs(struct mapped_device *md)
2673{
2674 int r;
2675
2676 WARN_ON(test_bit(DMF_FROZEN, &md->flags));
2677
2678 r = bdev_freeze(md->disk->part0);
2679 if (!r)
2680 set_bit(DMF_FROZEN, &md->flags);
2681 return r;
2682}
2683
2684static void unlock_fs(struct mapped_device *md)
2685{
2686 if (!test_bit(DMF_FROZEN, &md->flags))
2687 return;
2688 bdev_thaw(md->disk->part0);
2689 clear_bit(DMF_FROZEN, &md->flags);
2690}
2691
2692/*
2693 * @suspend_flags: DM_SUSPEND_LOCKFS_FLAG and/or DM_SUSPEND_NOFLUSH_FLAG
2694 * @task_state: e.g. TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE
2695 * @dmf_suspended_flag: DMF_SUSPENDED or DMF_SUSPENDED_INTERNALLY
2696 *
2697 * If __dm_suspend returns 0, the device is completely quiescent
2698 * now. There is no request-processing activity. All new requests
2699 * are being added to md->deferred list.
2700 */
2701static int __dm_suspend(struct mapped_device *md, struct dm_table *map,
2702 unsigned int suspend_flags, unsigned int task_state,
2703 int dmf_suspended_flag)
2704{
2705 bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG;
2706 bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG;
2707 int r;
2708
2709 lockdep_assert_held(&md->suspend_lock);
2710
2711 /*
2712 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2713 * This flag is cleared before dm_suspend returns.
2714 */
2715 if (noflush)
2716 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2717 else
2718 DMDEBUG("%s: suspending with flush", dm_device_name(md));
2719
2720 /*
2721 * This gets reverted if there's an error later and the targets
2722 * provide the .presuspend_undo hook.
2723 */
2724 dm_table_presuspend_targets(map);
2725
2726 /*
2727 * Flush I/O to the device.
2728 * Any I/O submitted after lock_fs() may not be flushed.
2729 * noflush takes precedence over do_lockfs.
2730 * (lock_fs() flushes I/Os and waits for them to complete.)
2731 */
2732 if (!noflush && do_lockfs) {
2733 r = lock_fs(md);
2734 if (r) {
2735 dm_table_presuspend_undo_targets(map);
2736 return r;
2737 }
2738 }
2739
2740 /*
2741 * Here we must make sure that no processes are submitting requests
2742 * to target drivers i.e. no one may be executing
2743 * dm_split_and_process_bio from dm_submit_bio.
2744 *
2745 * To get all processes out of dm_split_and_process_bio in dm_submit_bio,
2746 * we take the write lock. To prevent any process from reentering
2747 * dm_split_and_process_bio from dm_submit_bio and quiesce the thread
2748 * (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND and call
2749 * flush_workqueue(md->wq).
2750 */
2751 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2752 if (map)
2753 synchronize_srcu(&md->io_barrier);
2754
2755 /*
2756 * Stop md->queue before flushing md->wq in case request-based
2757 * dm defers requests to md->wq from md->queue.
2758 */
2759 if (dm_request_based(md))
2760 dm_stop_queue(md->queue);
2761
2762 flush_workqueue(md->wq);
2763
2764 /*
2765 * At this point no more requests are entering target request routines.
2766 * We call dm_wait_for_completion to wait for all existing requests
2767 * to finish.
2768 */
2769 r = dm_wait_for_completion(md, task_state);
2770 if (!r)
2771 set_bit(dmf_suspended_flag, &md->flags);
2772
2773 if (noflush)
2774 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2775 if (map)
2776 synchronize_srcu(&md->io_barrier);
2777
2778 /* were we interrupted ? */
2779 if (r < 0) {
2780 dm_queue_flush(md);
2781
2782 if (dm_request_based(md))
2783 dm_start_queue(md->queue);
2784
2785 unlock_fs(md);
2786 dm_table_presuspend_undo_targets(map);
2787 /* pushback list is already flushed, so skip flush */
2788 }
2789
2790 return r;
2791}
2792
2793/*
2794 * We need to be able to change a mapping table under a mounted
2795 * filesystem. For example we might want to move some data in
2796 * the background. Before the table can be swapped with
2797 * dm_bind_table, dm_suspend must be called to flush any in
2798 * flight bios and ensure that any further io gets deferred.
2799 */
2800/*
2801 * Suspend mechanism in request-based dm.
2802 *
2803 * 1. Flush all I/Os by lock_fs() if needed.
2804 * 2. Stop dispatching any I/O by stopping the request_queue.
2805 * 3. Wait for all in-flight I/Os to be completed or requeued.
2806 *
2807 * To abort suspend, start the request_queue.
2808 */
2809int dm_suspend(struct mapped_device *md, unsigned int suspend_flags)
2810{
2811 struct dm_table *map = NULL;
2812 int r = 0;
2813
2814retry:
2815 mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
2816
2817 if (dm_suspended_md(md)) {
2818 r = -EINVAL;
2819 goto out_unlock;
2820 }
2821
2822 if (dm_suspended_internally_md(md)) {
2823 /* already internally suspended, wait for internal resume */
2824 mutex_unlock(&md->suspend_lock);
2825 r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
2826 if (r)
2827 return r;
2828 goto retry;
2829 }
2830
2831 map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
2832 if (!map) {
2833 /* avoid deadlock with fs/namespace.c:do_mount() */
2834 suspend_flags &= ~DM_SUSPEND_LOCKFS_FLAG;
2835 }
2836
2837 r = __dm_suspend(md, map, suspend_flags, TASK_INTERRUPTIBLE, DMF_SUSPENDED);
2838 if (r)
2839 goto out_unlock;
2840
2841 set_bit(DMF_POST_SUSPENDING, &md->flags);
2842 dm_table_postsuspend_targets(map);
2843 clear_bit(DMF_POST_SUSPENDING, &md->flags);
2844
2845out_unlock:
2846 mutex_unlock(&md->suspend_lock);
2847 return r;
2848}
2849
2850static int __dm_resume(struct mapped_device *md, struct dm_table *map)
2851{
2852 if (map) {
2853 int r = dm_table_resume_targets(map);
2854
2855 if (r)
2856 return r;
2857 }
2858
2859 dm_queue_flush(md);
2860
2861 /*
2862 * Flushing deferred I/Os must be done after targets are resumed
2863 * so that mapping of targets can work correctly.
2864 * Request-based dm is queueing the deferred I/Os in its request_queue.
2865 */
2866 if (dm_request_based(md))
2867 dm_start_queue(md->queue);
2868
2869 unlock_fs(md);
2870
2871 return 0;
2872}
2873
2874int dm_resume(struct mapped_device *md)
2875{
2876 int r;
2877 struct dm_table *map = NULL;
2878
2879retry:
2880 r = -EINVAL;
2881 mutex_lock_nested(&md->suspend_lock, SINGLE_DEPTH_NESTING);
2882
2883 if (!dm_suspended_md(md))
2884 goto out;
2885
2886 if (dm_suspended_internally_md(md)) {
2887 /* already internally suspended, wait for internal resume */
2888 mutex_unlock(&md->suspend_lock);
2889 r = wait_on_bit(&md->flags, DMF_SUSPENDED_INTERNALLY, TASK_INTERRUPTIBLE);
2890 if (r)
2891 return r;
2892 goto retry;
2893 }
2894
2895 map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
2896 if (!map || !dm_table_get_size(map))
2897 goto out;
2898
2899 r = __dm_resume(md, map);
2900 if (r)
2901 goto out;
2902
2903 clear_bit(DMF_SUSPENDED, &md->flags);
2904out:
2905 mutex_unlock(&md->suspend_lock);
2906
2907 return r;
2908}
2909
2910/*
2911 * Internal suspend/resume works like userspace-driven suspend. It waits
2912 * until all bios finish and prevents issuing new bios to the target drivers.
2913 * It may be used only from the kernel.
2914 */
2915
2916static void __dm_internal_suspend(struct mapped_device *md, unsigned int suspend_flags)
2917{
2918 struct dm_table *map = NULL;
2919
2920 lockdep_assert_held(&md->suspend_lock);
2921
2922 if (md->internal_suspend_count++)
2923 return; /* nested internal suspend */
2924
2925 if (dm_suspended_md(md)) {
2926 set_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
2927 return; /* nest suspend */
2928 }
2929
2930 map = rcu_dereference_protected(md->map, lockdep_is_held(&md->suspend_lock));
2931
2932 /*
2933 * Using TASK_UNINTERRUPTIBLE because only NOFLUSH internal suspend is
2934 * supported. Properly supporting a TASK_INTERRUPTIBLE internal suspend
2935 * would require changing .presuspend to return an error -- avoid this
2936 * until there is a need for more elaborate variants of internal suspend.
2937 */
2938 (void) __dm_suspend(md, map, suspend_flags, TASK_UNINTERRUPTIBLE,
2939 DMF_SUSPENDED_INTERNALLY);
2940
2941 set_bit(DMF_POST_SUSPENDING, &md->flags);
2942 dm_table_postsuspend_targets(map);
2943 clear_bit(DMF_POST_SUSPENDING, &md->flags);
2944}
2945
2946static void __dm_internal_resume(struct mapped_device *md)
2947{
2948 BUG_ON(!md->internal_suspend_count);
2949
2950 if (--md->internal_suspend_count)
2951 return; /* resume from nested internal suspend */
2952
2953 if (dm_suspended_md(md))
2954 goto done; /* resume from nested suspend */
2955
2956 /*
2957 * NOTE: existing callers don't need to call dm_table_resume_targets
2958 * (which may fail -- so best to avoid it for now by passing NULL map)
2959 */
2960 (void) __dm_resume(md, NULL);
2961
2962done:
2963 clear_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
2964 smp_mb__after_atomic();
2965 wake_up_bit(&md->flags, DMF_SUSPENDED_INTERNALLY);
2966}
2967
2968void dm_internal_suspend_noflush(struct mapped_device *md)
2969{
2970 mutex_lock(&md->suspend_lock);
2971 __dm_internal_suspend(md, DM_SUSPEND_NOFLUSH_FLAG);
2972 mutex_unlock(&md->suspend_lock);
2973}
2974EXPORT_SYMBOL_GPL(dm_internal_suspend_noflush);
2975
2976void dm_internal_resume(struct mapped_device *md)
2977{
2978 mutex_lock(&md->suspend_lock);
2979 __dm_internal_resume(md);
2980 mutex_unlock(&md->suspend_lock);
2981}
2982EXPORT_SYMBOL_GPL(dm_internal_resume);
2983
2984/*
2985 * Fast variants of internal suspend/resume hold md->suspend_lock,
2986 * which prevents interaction with userspace-driven suspend.
2987 */
2988
2989void dm_internal_suspend_fast(struct mapped_device *md)
2990{
2991 mutex_lock(&md->suspend_lock);
2992 if (dm_suspended_md(md) || dm_suspended_internally_md(md))
2993 return;
2994
2995 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2996 synchronize_srcu(&md->io_barrier);
2997 flush_workqueue(md->wq);
2998 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2999}
3000EXPORT_SYMBOL_GPL(dm_internal_suspend_fast);
3001
3002void dm_internal_resume_fast(struct mapped_device *md)
3003{
3004 if (dm_suspended_md(md) || dm_suspended_internally_md(md))
3005 goto done;
3006
3007 dm_queue_flush(md);
3008
3009done:
3010 mutex_unlock(&md->suspend_lock);
3011}
3012EXPORT_SYMBOL_GPL(dm_internal_resume_fast);
3013
3014/*
3015 *---------------------------------------------------------------
3016 * Event notification.
3017 *---------------------------------------------------------------
3018 */
3019int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
3020 unsigned int cookie, bool need_resize_uevent)
3021{
3022 int r;
3023 unsigned int noio_flag;
3024 char udev_cookie[DM_COOKIE_LENGTH];
3025 char *envp[3] = { NULL, NULL, NULL };
3026 char **envpp = envp;
3027 if (cookie) {
3028 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
3029 DM_COOKIE_ENV_VAR_NAME, cookie);
3030 *envpp++ = udev_cookie;
3031 }
3032 if (need_resize_uevent) {
3033 *envpp++ = "RESIZE=1";
3034 }
3035
3036 noio_flag = memalloc_noio_save();
3037
3038 r = kobject_uevent_env(&disk_to_dev(md->disk)->kobj, action, envp);
3039
3040 memalloc_noio_restore(noio_flag);
3041
3042 return r;
3043}
3044
3045uint32_t dm_next_uevent_seq(struct mapped_device *md)
3046{
3047 return atomic_add_return(1, &md->uevent_seq);
3048}
3049
3050uint32_t dm_get_event_nr(struct mapped_device *md)
3051{
3052 return atomic_read(&md->event_nr);
3053}
3054
3055int dm_wait_event(struct mapped_device *md, int event_nr)
3056{
3057 return wait_event_interruptible(md->eventq,
3058 (event_nr != atomic_read(&md->event_nr)));
3059}
3060
3061void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
3062{
3063 unsigned long flags;
3064
3065 spin_lock_irqsave(&md->uevent_lock, flags);
3066 list_add(elist, &md->uevent_list);
3067 spin_unlock_irqrestore(&md->uevent_lock, flags);
3068}
3069
3070/*
3071 * The gendisk is only valid as long as you have a reference
3072 * count on 'md'.
3073 */
3074struct gendisk *dm_disk(struct mapped_device *md)
3075{
3076 return md->disk;
3077}
3078EXPORT_SYMBOL_GPL(dm_disk);
3079
3080struct kobject *dm_kobject(struct mapped_device *md)
3081{
3082 return &md->kobj_holder.kobj;
3083}
3084
3085struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
3086{
3087 struct mapped_device *md;
3088
3089 md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
3090
3091 spin_lock(&_minor_lock);
3092 if (test_bit(DMF_FREEING, &md->flags) || dm_deleting_md(md)) {
3093 md = NULL;
3094 goto out;
3095 }
3096 dm_get(md);
3097out:
3098 spin_unlock(&_minor_lock);
3099
3100 return md;
3101}
3102
3103int dm_suspended_md(struct mapped_device *md)
3104{
3105 return test_bit(DMF_SUSPENDED, &md->flags);
3106}
3107
3108static int dm_post_suspending_md(struct mapped_device *md)
3109{
3110 return test_bit(DMF_POST_SUSPENDING, &md->flags);
3111}
3112
3113int dm_suspended_internally_md(struct mapped_device *md)
3114{
3115 return test_bit(DMF_SUSPENDED_INTERNALLY, &md->flags);
3116}
3117
3118int dm_test_deferred_remove_flag(struct mapped_device *md)
3119{
3120 return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
3121}
3122
3123int dm_suspended(struct dm_target *ti)
3124{
3125 return dm_suspended_md(ti->table->md);
3126}
3127EXPORT_SYMBOL_GPL(dm_suspended);
3128
3129int dm_post_suspending(struct dm_target *ti)
3130{
3131 return dm_post_suspending_md(ti->table->md);
3132}
3133EXPORT_SYMBOL_GPL(dm_post_suspending);
3134
3135int dm_noflush_suspending(struct dm_target *ti)
3136{
3137 return __noflush_suspending(ti->table->md);
3138}
3139EXPORT_SYMBOL_GPL(dm_noflush_suspending);
3140
3141void dm_free_md_mempools(struct dm_md_mempools *pools)
3142{
3143 if (!pools)
3144 return;
3145
3146 bioset_exit(&pools->bs);
3147 bioset_exit(&pools->io_bs);
3148
3149 kfree(pools);
3150}
3151
3152struct dm_pr {
3153 u64 old_key;
3154 u64 new_key;
3155 u32 flags;
3156 bool abort;
3157 bool fail_early;
3158 int ret;
3159 enum pr_type type;
3160 struct pr_keys *read_keys;
3161 struct pr_held_reservation *rsv;
3162};
3163
3164static int dm_call_pr(struct block_device *bdev, iterate_devices_callout_fn fn,
3165 struct dm_pr *pr)
3166{
3167 struct mapped_device *md = bdev->bd_disk->private_data;
3168 struct dm_table *table;
3169 struct dm_target *ti;
3170 int ret = -ENOTTY, srcu_idx;
3171
3172 table = dm_get_live_table(md, &srcu_idx);
3173 if (!table || !dm_table_get_size(table))
3174 goto out;
3175
3176 /* We only support devices that have a single target */
3177 if (table->num_targets != 1)
3178 goto out;
3179 ti = dm_table_get_target(table, 0);
3180
3181 if (dm_suspended_md(md)) {
3182 ret = -EAGAIN;
3183 goto out;
3184 }
3185
3186 ret = -EINVAL;
3187 if (!ti->type->iterate_devices)
3188 goto out;
3189
3190 ti->type->iterate_devices(ti, fn, pr);
3191 ret = 0;
3192out:
3193 dm_put_live_table(md, srcu_idx);
3194 return ret;
3195}
3196
3197/*
3198 * For register / unregister we need to manually call out to every path.
3199 */
3200static int __dm_pr_register(struct dm_target *ti, struct dm_dev *dev,
3201 sector_t start, sector_t len, void *data)
3202{
3203 struct dm_pr *pr = data;
3204 const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
3205 int ret;
3206
3207 if (!ops || !ops->pr_register) {
3208 pr->ret = -EOPNOTSUPP;
3209 return -1;
3210 }
3211
3212 ret = ops->pr_register(dev->bdev, pr->old_key, pr->new_key, pr->flags);
3213 if (!ret)
3214 return 0;
3215
3216 if (!pr->ret)
3217 pr->ret = ret;
3218
3219 if (pr->fail_early)
3220 return -1;
3221
3222 return 0;
3223}
3224
3225static int dm_pr_register(struct block_device *bdev, u64 old_key, u64 new_key,
3226 u32 flags)
3227{
3228 struct dm_pr pr = {
3229 .old_key = old_key,
3230 .new_key = new_key,
3231 .flags = flags,
3232 .fail_early = true,
3233 .ret = 0,
3234 };
3235 int ret;
3236
3237 ret = dm_call_pr(bdev, __dm_pr_register, &pr);
3238 if (ret) {
3239 /* Didn't even get to register a path */
3240 return ret;
3241 }
3242
3243 if (!pr.ret)
3244 return 0;
3245 ret = pr.ret;
3246
3247 if (!new_key)
3248 return ret;
3249
3250 /* unregister all paths if we failed to register any path */
3251 pr.old_key = new_key;
3252 pr.new_key = 0;
3253 pr.flags = 0;
3254 pr.fail_early = false;
3255 (void) dm_call_pr(bdev, __dm_pr_register, &pr);
3256 return ret;
3257}
3258
3259
3260static int __dm_pr_reserve(struct dm_target *ti, struct dm_dev *dev,
3261 sector_t start, sector_t len, void *data)
3262{
3263 struct dm_pr *pr = data;
3264 const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
3265
3266 if (!ops || !ops->pr_reserve) {
3267 pr->ret = -EOPNOTSUPP;
3268 return -1;
3269 }
3270
3271 pr->ret = ops->pr_reserve(dev->bdev, pr->old_key, pr->type, pr->flags);
3272 if (!pr->ret)
3273 return -1;
3274
3275 return 0;
3276}
3277
3278static int dm_pr_reserve(struct block_device *bdev, u64 key, enum pr_type type,
3279 u32 flags)
3280{
3281 struct dm_pr pr = {
3282 .old_key = key,
3283 .flags = flags,
3284 .type = type,
3285 .fail_early = false,
3286 .ret = 0,
3287 };
3288 int ret;
3289
3290 ret = dm_call_pr(bdev, __dm_pr_reserve, &pr);
3291 if (ret)
3292 return ret;
3293
3294 return pr.ret;
3295}
3296
3297/*
3298 * If there is a non-All Registrants type of reservation, the release must be
3299 * sent down the holding path. For the cases where there is no reservation or
3300 * the path is not the holder the device will also return success, so we must
3301 * try each path to make sure we got the correct path.
3302 */
3303static int __dm_pr_release(struct dm_target *ti, struct dm_dev *dev,
3304 sector_t start, sector_t len, void *data)
3305{
3306 struct dm_pr *pr = data;
3307 const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
3308
3309 if (!ops || !ops->pr_release) {
3310 pr->ret = -EOPNOTSUPP;
3311 return -1;
3312 }
3313
3314 pr->ret = ops->pr_release(dev->bdev, pr->old_key, pr->type);
3315 if (pr->ret)
3316 return -1;
3317
3318 return 0;
3319}
3320
3321static int dm_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
3322{
3323 struct dm_pr pr = {
3324 .old_key = key,
3325 .type = type,
3326 .fail_early = false,
3327 };
3328 int ret;
3329
3330 ret = dm_call_pr(bdev, __dm_pr_release, &pr);
3331 if (ret)
3332 return ret;
3333
3334 return pr.ret;
3335}
3336
3337static int __dm_pr_preempt(struct dm_target *ti, struct dm_dev *dev,
3338 sector_t start, sector_t len, void *data)
3339{
3340 struct dm_pr *pr = data;
3341 const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
3342
3343 if (!ops || !ops->pr_preempt) {
3344 pr->ret = -EOPNOTSUPP;
3345 return -1;
3346 }
3347
3348 pr->ret = ops->pr_preempt(dev->bdev, pr->old_key, pr->new_key, pr->type,
3349 pr->abort);
3350 if (!pr->ret)
3351 return -1;
3352
3353 return 0;
3354}
3355
3356static int dm_pr_preempt(struct block_device *bdev, u64 old_key, u64 new_key,
3357 enum pr_type type, bool abort)
3358{
3359 struct dm_pr pr = {
3360 .new_key = new_key,
3361 .old_key = old_key,
3362 .type = type,
3363 .fail_early = false,
3364 };
3365 int ret;
3366
3367 ret = dm_call_pr(bdev, __dm_pr_preempt, &pr);
3368 if (ret)
3369 return ret;
3370
3371 return pr.ret;
3372}
3373
3374static int dm_pr_clear(struct block_device *bdev, u64 key)
3375{
3376 struct mapped_device *md = bdev->bd_disk->private_data;
3377 const struct pr_ops *ops;
3378 int r, srcu_idx;
3379
3380 r = dm_prepare_ioctl(md, &srcu_idx, &bdev);
3381 if (r < 0)
3382 goto out;
3383
3384 ops = bdev->bd_disk->fops->pr_ops;
3385 if (ops && ops->pr_clear)
3386 r = ops->pr_clear(bdev, key);
3387 else
3388 r = -EOPNOTSUPP;
3389out:
3390 dm_unprepare_ioctl(md, srcu_idx);
3391 return r;
3392}
3393
3394static int __dm_pr_read_keys(struct dm_target *ti, struct dm_dev *dev,
3395 sector_t start, sector_t len, void *data)
3396{
3397 struct dm_pr *pr = data;
3398 const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
3399
3400 if (!ops || !ops->pr_read_keys) {
3401 pr->ret = -EOPNOTSUPP;
3402 return -1;
3403 }
3404
3405 pr->ret = ops->pr_read_keys(dev->bdev, pr->read_keys);
3406 if (!pr->ret)
3407 return -1;
3408
3409 return 0;
3410}
3411
3412static int dm_pr_read_keys(struct block_device *bdev, struct pr_keys *keys)
3413{
3414 struct dm_pr pr = {
3415 .read_keys = keys,
3416 };
3417 int ret;
3418
3419 ret = dm_call_pr(bdev, __dm_pr_read_keys, &pr);
3420 if (ret)
3421 return ret;
3422
3423 return pr.ret;
3424}
3425
3426static int __dm_pr_read_reservation(struct dm_target *ti, struct dm_dev *dev,
3427 sector_t start, sector_t len, void *data)
3428{
3429 struct dm_pr *pr = data;
3430 const struct pr_ops *ops = dev->bdev->bd_disk->fops->pr_ops;
3431
3432 if (!ops || !ops->pr_read_reservation) {
3433 pr->ret = -EOPNOTSUPP;
3434 return -1;
3435 }
3436
3437 pr->ret = ops->pr_read_reservation(dev->bdev, pr->rsv);
3438 if (!pr->ret)
3439 return -1;
3440
3441 return 0;
3442}
3443
3444static int dm_pr_read_reservation(struct block_device *bdev,
3445 struct pr_held_reservation *rsv)
3446{
3447 struct dm_pr pr = {
3448 .rsv = rsv,
3449 };
3450 int ret;
3451
3452 ret = dm_call_pr(bdev, __dm_pr_read_reservation, &pr);
3453 if (ret)
3454 return ret;
3455
3456 return pr.ret;
3457}
3458
3459static const struct pr_ops dm_pr_ops = {
3460 .pr_register = dm_pr_register,
3461 .pr_reserve = dm_pr_reserve,
3462 .pr_release = dm_pr_release,
3463 .pr_preempt = dm_pr_preempt,
3464 .pr_clear = dm_pr_clear,
3465 .pr_read_keys = dm_pr_read_keys,
3466 .pr_read_reservation = dm_pr_read_reservation,
3467};
3468
3469static const struct block_device_operations dm_blk_dops = {
3470 .submit_bio = dm_submit_bio,
3471 .poll_bio = dm_poll_bio,
3472 .open = dm_blk_open,
3473 .release = dm_blk_close,
3474 .ioctl = dm_blk_ioctl,
3475 .getgeo = dm_blk_getgeo,
3476 .report_zones = dm_blk_report_zones,
3477 .pr_ops = &dm_pr_ops,
3478 .owner = THIS_MODULE
3479};
3480
3481static const struct block_device_operations dm_rq_blk_dops = {
3482 .open = dm_blk_open,
3483 .release = dm_blk_close,
3484 .ioctl = dm_blk_ioctl,
3485 .getgeo = dm_blk_getgeo,
3486 .pr_ops = &dm_pr_ops,
3487 .owner = THIS_MODULE
3488};
3489
3490static const struct dax_operations dm_dax_ops = {
3491 .direct_access = dm_dax_direct_access,
3492 .zero_page_range = dm_dax_zero_page_range,
3493 .recovery_write = dm_dax_recovery_write,
3494};
3495
3496/*
3497 * module hooks
3498 */
3499module_init(dm_init);
3500module_exit(dm_exit);
3501
3502module_param(major, uint, 0);
3503MODULE_PARM_DESC(major, "The major number of the device mapper");
3504
3505module_param(reserved_bio_based_ios, uint, 0644);
3506MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
3507
3508module_param(dm_numa_node, int, 0644);
3509MODULE_PARM_DESC(dm_numa_node, "NUMA node for DM device memory allocations");
3510
3511module_param(swap_bios, int, 0644);
3512MODULE_PARM_DESC(swap_bios, "Maximum allowed inflight swap IOs");
3513
3514MODULE_DESCRIPTION(DM_NAME " driver");
3515MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
3516MODULE_LICENSE("GPL");
1/*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"
9#include "dm-uevent.h"
10
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
23#include <trace/events/block.h>
24
25#define DM_MSG_PREFIX "core"
26
27#ifdef CONFIG_PRINTK
28/*
29 * ratelimit state to be used in DMXXX_LIMIT().
30 */
31DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
32 DEFAULT_RATELIMIT_INTERVAL,
33 DEFAULT_RATELIMIT_BURST);
34EXPORT_SYMBOL(dm_ratelimit_state);
35#endif
36
37/*
38 * Cookies are numeric values sent with CHANGE and REMOVE
39 * uevents while resuming, removing or renaming the device.
40 */
41#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
42#define DM_COOKIE_LENGTH 24
43
44static const char *_name = DM_NAME;
45
46static unsigned int major = 0;
47static unsigned int _major = 0;
48
49static DEFINE_IDR(_minor_idr);
50
51static DEFINE_SPINLOCK(_minor_lock);
52
53static void do_deferred_remove(struct work_struct *w);
54
55static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
56
57/*
58 * For bio-based dm.
59 * One of these is allocated per bio.
60 */
61struct dm_io {
62 struct mapped_device *md;
63 int error;
64 atomic_t io_count;
65 struct bio *bio;
66 unsigned long start_time;
67 spinlock_t endio_lock;
68 struct dm_stats_aux stats_aux;
69};
70
71/*
72 * For request-based dm.
73 * One of these is allocated per request.
74 */
75struct dm_rq_target_io {
76 struct mapped_device *md;
77 struct dm_target *ti;
78 struct request *orig, clone;
79 int error;
80 union map_info info;
81};
82
83/*
84 * For request-based dm - the bio clones we allocate are embedded in these
85 * structs.
86 *
87 * We allocate these with bio_alloc_bioset, using the front_pad parameter when
88 * the bioset is created - this means the bio has to come at the end of the
89 * struct.
90 */
91struct dm_rq_clone_bio_info {
92 struct bio *orig;
93 struct dm_rq_target_io *tio;
94 struct bio clone;
95};
96
97union map_info *dm_get_rq_mapinfo(struct request *rq)
98{
99 if (rq && rq->end_io_data)
100 return &((struct dm_rq_target_io *)rq->end_io_data)->info;
101 return NULL;
102}
103EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
104
105#define MINOR_ALLOCED ((void *)-1)
106
107/*
108 * Bits for the md->flags field.
109 */
110#define DMF_BLOCK_IO_FOR_SUSPEND 0
111#define DMF_SUSPENDED 1
112#define DMF_FROZEN 2
113#define DMF_FREEING 3
114#define DMF_DELETING 4
115#define DMF_NOFLUSH_SUSPENDING 5
116#define DMF_MERGE_IS_OPTIONAL 6
117#define DMF_DEFERRED_REMOVE 7
118
119/*
120 * A dummy definition to make RCU happy.
121 * struct dm_table should never be dereferenced in this file.
122 */
123struct dm_table {
124 int undefined__;
125};
126
127/*
128 * Work processed by per-device workqueue.
129 */
130struct mapped_device {
131 struct srcu_struct io_barrier;
132 struct mutex suspend_lock;
133 atomic_t holders;
134 atomic_t open_count;
135
136 /*
137 * The current mapping.
138 * Use dm_get_live_table{_fast} or take suspend_lock for
139 * dereference.
140 */
141 struct dm_table *map;
142
143 unsigned long flags;
144
145 struct request_queue *queue;
146 unsigned type;
147 /* Protect queue and type against concurrent access. */
148 struct mutex type_lock;
149
150 struct target_type *immutable_target_type;
151
152 struct gendisk *disk;
153 char name[16];
154
155 void *interface_ptr;
156
157 /*
158 * A list of ios that arrived while we were suspended.
159 */
160 atomic_t pending[2];
161 wait_queue_head_t wait;
162 struct work_struct work;
163 struct bio_list deferred;
164 spinlock_t deferred_lock;
165
166 /*
167 * Processing queue (flush)
168 */
169 struct workqueue_struct *wq;
170
171 /*
172 * io objects are allocated from here.
173 */
174 mempool_t *io_pool;
175
176 struct bio_set *bs;
177
178 /*
179 * Event handling.
180 */
181 atomic_t event_nr;
182 wait_queue_head_t eventq;
183 atomic_t uevent_seq;
184 struct list_head uevent_list;
185 spinlock_t uevent_lock; /* Protect access to uevent_list */
186
187 /*
188 * freeze/thaw support require holding onto a super block
189 */
190 struct super_block *frozen_sb;
191 struct block_device *bdev;
192
193 /* forced geometry settings */
194 struct hd_geometry geometry;
195
196 /* kobject and completion */
197 struct dm_kobject_holder kobj_holder;
198
199 /* zero-length flush that will be cloned and submitted to targets */
200 struct bio flush_bio;
201
202 struct dm_stats stats;
203};
204
205/*
206 * For mempools pre-allocation at the table loading time.
207 */
208struct dm_md_mempools {
209 mempool_t *io_pool;
210 struct bio_set *bs;
211};
212
213#define RESERVED_BIO_BASED_IOS 16
214#define RESERVED_REQUEST_BASED_IOS 256
215#define RESERVED_MAX_IOS 1024
216static struct kmem_cache *_io_cache;
217static struct kmem_cache *_rq_tio_cache;
218
219/*
220 * Bio-based DM's mempools' reserved IOs set by the user.
221 */
222static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
223
224/*
225 * Request-based DM's mempools' reserved IOs set by the user.
226 */
227static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
228
229static unsigned __dm_get_reserved_ios(unsigned *reserved_ios,
230 unsigned def, unsigned max)
231{
232 unsigned ios = ACCESS_ONCE(*reserved_ios);
233 unsigned modified_ios = 0;
234
235 if (!ios)
236 modified_ios = def;
237 else if (ios > max)
238 modified_ios = max;
239
240 if (modified_ios) {
241 (void)cmpxchg(reserved_ios, ios, modified_ios);
242 ios = modified_ios;
243 }
244
245 return ios;
246}
247
248unsigned dm_get_reserved_bio_based_ios(void)
249{
250 return __dm_get_reserved_ios(&reserved_bio_based_ios,
251 RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);
252}
253EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
254
255unsigned dm_get_reserved_rq_based_ios(void)
256{
257 return __dm_get_reserved_ios(&reserved_rq_based_ios,
258 RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS);
259}
260EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
261
262static int __init local_init(void)
263{
264 int r = -ENOMEM;
265
266 /* allocate a slab for the dm_ios */
267 _io_cache = KMEM_CACHE(dm_io, 0);
268 if (!_io_cache)
269 return r;
270
271 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
272 if (!_rq_tio_cache)
273 goto out_free_io_cache;
274
275 r = dm_uevent_init();
276 if (r)
277 goto out_free_rq_tio_cache;
278
279 _major = major;
280 r = register_blkdev(_major, _name);
281 if (r < 0)
282 goto out_uevent_exit;
283
284 if (!_major)
285 _major = r;
286
287 return 0;
288
289out_uevent_exit:
290 dm_uevent_exit();
291out_free_rq_tio_cache:
292 kmem_cache_destroy(_rq_tio_cache);
293out_free_io_cache:
294 kmem_cache_destroy(_io_cache);
295
296 return r;
297}
298
299static void local_exit(void)
300{
301 flush_scheduled_work();
302
303 kmem_cache_destroy(_rq_tio_cache);
304 kmem_cache_destroy(_io_cache);
305 unregister_blkdev(_major, _name);
306 dm_uevent_exit();
307
308 _major = 0;
309
310 DMINFO("cleaned up");
311}
312
313static int (*_inits[])(void) __initdata = {
314 local_init,
315 dm_target_init,
316 dm_linear_init,
317 dm_stripe_init,
318 dm_io_init,
319 dm_kcopyd_init,
320 dm_interface_init,
321 dm_statistics_init,
322};
323
324static void (*_exits[])(void) = {
325 local_exit,
326 dm_target_exit,
327 dm_linear_exit,
328 dm_stripe_exit,
329 dm_io_exit,
330 dm_kcopyd_exit,
331 dm_interface_exit,
332 dm_statistics_exit,
333};
334
335static int __init dm_init(void)
336{
337 const int count = ARRAY_SIZE(_inits);
338
339 int r, i;
340
341 for (i = 0; i < count; i++) {
342 r = _inits[i]();
343 if (r)
344 goto bad;
345 }
346
347 return 0;
348
349 bad:
350 while (i--)
351 _exits[i]();
352
353 return r;
354}
355
356static void __exit dm_exit(void)
357{
358 int i = ARRAY_SIZE(_exits);
359
360 while (i--)
361 _exits[i]();
362
363 /*
364 * Should be empty by this point.
365 */
366 idr_destroy(&_minor_idr);
367}
368
369/*
370 * Block device functions
371 */
372int dm_deleting_md(struct mapped_device *md)
373{
374 return test_bit(DMF_DELETING, &md->flags);
375}
376
377static int dm_blk_open(struct block_device *bdev, fmode_t mode)
378{
379 struct mapped_device *md;
380
381 spin_lock(&_minor_lock);
382
383 md = bdev->bd_disk->private_data;
384 if (!md)
385 goto out;
386
387 if (test_bit(DMF_FREEING, &md->flags) ||
388 dm_deleting_md(md)) {
389 md = NULL;
390 goto out;
391 }
392
393 dm_get(md);
394 atomic_inc(&md->open_count);
395
396out:
397 spin_unlock(&_minor_lock);
398
399 return md ? 0 : -ENXIO;
400}
401
402static void dm_blk_close(struct gendisk *disk, fmode_t mode)
403{
404 struct mapped_device *md = disk->private_data;
405
406 spin_lock(&_minor_lock);
407
408 if (atomic_dec_and_test(&md->open_count) &&
409 (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
410 schedule_work(&deferred_remove_work);
411
412 dm_put(md);
413
414 spin_unlock(&_minor_lock);
415}
416
417int dm_open_count(struct mapped_device *md)
418{
419 return atomic_read(&md->open_count);
420}
421
422/*
423 * Guarantees nothing is using the device before it's deleted.
424 */
425int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
426{
427 int r = 0;
428
429 spin_lock(&_minor_lock);
430
431 if (dm_open_count(md)) {
432 r = -EBUSY;
433 if (mark_deferred)
434 set_bit(DMF_DEFERRED_REMOVE, &md->flags);
435 } else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
436 r = -EEXIST;
437 else
438 set_bit(DMF_DELETING, &md->flags);
439
440 spin_unlock(&_minor_lock);
441
442 return r;
443}
444
445int dm_cancel_deferred_remove(struct mapped_device *md)
446{
447 int r = 0;
448
449 spin_lock(&_minor_lock);
450
451 if (test_bit(DMF_DELETING, &md->flags))
452 r = -EBUSY;
453 else
454 clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
455
456 spin_unlock(&_minor_lock);
457
458 return r;
459}
460
461static void do_deferred_remove(struct work_struct *w)
462{
463 dm_deferred_remove();
464}
465
466sector_t dm_get_size(struct mapped_device *md)
467{
468 return get_capacity(md->disk);
469}
470
471struct request_queue *dm_get_md_queue(struct mapped_device *md)
472{
473 return md->queue;
474}
475
476struct dm_stats *dm_get_stats(struct mapped_device *md)
477{
478 return &md->stats;
479}
480
481static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
482{
483 struct mapped_device *md = bdev->bd_disk->private_data;
484
485 return dm_get_geometry(md, geo);
486}
487
488static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
489 unsigned int cmd, unsigned long arg)
490{
491 struct mapped_device *md = bdev->bd_disk->private_data;
492 int srcu_idx;
493 struct dm_table *map;
494 struct dm_target *tgt;
495 int r = -ENOTTY;
496
497retry:
498 map = dm_get_live_table(md, &srcu_idx);
499
500 if (!map || !dm_table_get_size(map))
501 goto out;
502
503 /* We only support devices that have a single target */
504 if (dm_table_get_num_targets(map) != 1)
505 goto out;
506
507 tgt = dm_table_get_target(map, 0);
508
509 if (dm_suspended_md(md)) {
510 r = -EAGAIN;
511 goto out;
512 }
513
514 if (tgt->type->ioctl)
515 r = tgt->type->ioctl(tgt, cmd, arg);
516
517out:
518 dm_put_live_table(md, srcu_idx);
519
520 if (r == -ENOTCONN) {
521 msleep(10);
522 goto retry;
523 }
524
525 return r;
526}
527
528static struct dm_io *alloc_io(struct mapped_device *md)
529{
530 return mempool_alloc(md->io_pool, GFP_NOIO);
531}
532
533static void free_io(struct mapped_device *md, struct dm_io *io)
534{
535 mempool_free(io, md->io_pool);
536}
537
538static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
539{
540 bio_put(&tio->clone);
541}
542
543static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
544 gfp_t gfp_mask)
545{
546 return mempool_alloc(md->io_pool, gfp_mask);
547}
548
549static void free_rq_tio(struct dm_rq_target_io *tio)
550{
551 mempool_free(tio, tio->md->io_pool);
552}
553
554static int md_in_flight(struct mapped_device *md)
555{
556 return atomic_read(&md->pending[READ]) +
557 atomic_read(&md->pending[WRITE]);
558}
559
560static void start_io_acct(struct dm_io *io)
561{
562 struct mapped_device *md = io->md;
563 struct bio *bio = io->bio;
564 int cpu;
565 int rw = bio_data_dir(bio);
566
567 io->start_time = jiffies;
568
569 cpu = part_stat_lock();
570 part_round_stats(cpu, &dm_disk(md)->part0);
571 part_stat_unlock();
572 atomic_set(&dm_disk(md)->part0.in_flight[rw],
573 atomic_inc_return(&md->pending[rw]));
574
575 if (unlikely(dm_stats_used(&md->stats)))
576 dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
577 bio_sectors(bio), false, 0, &io->stats_aux);
578}
579
580static void end_io_acct(struct dm_io *io)
581{
582 struct mapped_device *md = io->md;
583 struct bio *bio = io->bio;
584 unsigned long duration = jiffies - io->start_time;
585 int pending, cpu;
586 int rw = bio_data_dir(bio);
587
588 cpu = part_stat_lock();
589 part_round_stats(cpu, &dm_disk(md)->part0);
590 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
591 part_stat_unlock();
592
593 if (unlikely(dm_stats_used(&md->stats)))
594 dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
595 bio_sectors(bio), true, duration, &io->stats_aux);
596
597 /*
598 * After this is decremented the bio must not be touched if it is
599 * a flush.
600 */
601 pending = atomic_dec_return(&md->pending[rw]);
602 atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
603 pending += atomic_read(&md->pending[rw^0x1]);
604
605 /* nudge anyone waiting on suspend queue */
606 if (!pending)
607 wake_up(&md->wait);
608}
609
610/*
611 * Add the bio to the list of deferred io.
612 */
613static void queue_io(struct mapped_device *md, struct bio *bio)
614{
615 unsigned long flags;
616
617 spin_lock_irqsave(&md->deferred_lock, flags);
618 bio_list_add(&md->deferred, bio);
619 spin_unlock_irqrestore(&md->deferred_lock, flags);
620 queue_work(md->wq, &md->work);
621}
622
623/*
624 * Everyone (including functions in this file), should use this
625 * function to access the md->map field, and make sure they call
626 * dm_put_live_table() when finished.
627 */
628struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx) __acquires(md->io_barrier)
629{
630 *srcu_idx = srcu_read_lock(&md->io_barrier);
631
632 return srcu_dereference(md->map, &md->io_barrier);
633}
634
635void dm_put_live_table(struct mapped_device *md, int srcu_idx) __releases(md->io_barrier)
636{
637 srcu_read_unlock(&md->io_barrier, srcu_idx);
638}
639
640void dm_sync_table(struct mapped_device *md)
641{
642 synchronize_srcu(&md->io_barrier);
643 synchronize_rcu_expedited();
644}
645
646/*
647 * A fast alternative to dm_get_live_table/dm_put_live_table.
648 * The caller must not block between these two functions.
649 */
650static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
651{
652 rcu_read_lock();
653 return rcu_dereference(md->map);
654}
655
656static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
657{
658 rcu_read_unlock();
659}
660
661/*
662 * Get the geometry associated with a dm device
663 */
664int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
665{
666 *geo = md->geometry;
667
668 return 0;
669}
670
671/*
672 * Set the geometry of a device.
673 */
674int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
675{
676 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
677
678 if (geo->start > sz) {
679 DMWARN("Start sector is beyond the geometry limits.");
680 return -EINVAL;
681 }
682
683 md->geometry = *geo;
684
685 return 0;
686}
687
688/*-----------------------------------------------------------------
689 * CRUD START:
690 * A more elegant soln is in the works that uses the queue
691 * merge fn, unfortunately there are a couple of changes to
692 * the block layer that I want to make for this. So in the
693 * interests of getting something for people to use I give
694 * you this clearly demarcated crap.
695 *---------------------------------------------------------------*/
696
697static int __noflush_suspending(struct mapped_device *md)
698{
699 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
700}
701
702/*
703 * Decrements the number of outstanding ios that a bio has been
704 * cloned into, completing the original io if necc.
705 */
706static void dec_pending(struct dm_io *io, int error)
707{
708 unsigned long flags;
709 int io_error;
710 struct bio *bio;
711 struct mapped_device *md = io->md;
712
713 /* Push-back supersedes any I/O errors */
714 if (unlikely(error)) {
715 spin_lock_irqsave(&io->endio_lock, flags);
716 if (!(io->error > 0 && __noflush_suspending(md)))
717 io->error = error;
718 spin_unlock_irqrestore(&io->endio_lock, flags);
719 }
720
721 if (atomic_dec_and_test(&io->io_count)) {
722 if (io->error == DM_ENDIO_REQUEUE) {
723 /*
724 * Target requested pushing back the I/O.
725 */
726 spin_lock_irqsave(&md->deferred_lock, flags);
727 if (__noflush_suspending(md))
728 bio_list_add_head(&md->deferred, io->bio);
729 else
730 /* noflush suspend was interrupted. */
731 io->error = -EIO;
732 spin_unlock_irqrestore(&md->deferred_lock, flags);
733 }
734
735 io_error = io->error;
736 bio = io->bio;
737 end_io_acct(io);
738 free_io(md, io);
739
740 if (io_error == DM_ENDIO_REQUEUE)
741 return;
742
743 if ((bio->bi_rw & REQ_FLUSH) && bio->bi_iter.bi_size) {
744 /*
745 * Preflush done for flush with data, reissue
746 * without REQ_FLUSH.
747 */
748 bio->bi_rw &= ~REQ_FLUSH;
749 queue_io(md, bio);
750 } else {
751 /* done with normal IO or empty flush */
752 trace_block_bio_complete(md->queue, bio, io_error);
753 bio_endio(bio, io_error);
754 }
755 }
756}
757
758static void clone_endio(struct bio *bio, int error)
759{
760 int r = 0;
761 struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
762 struct dm_io *io = tio->io;
763 struct mapped_device *md = tio->io->md;
764 dm_endio_fn endio = tio->ti->type->end_io;
765
766 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
767 error = -EIO;
768
769 if (endio) {
770 r = endio(tio->ti, bio, error);
771 if (r < 0 || r == DM_ENDIO_REQUEUE)
772 /*
773 * error and requeue request are handled
774 * in dec_pending().
775 */
776 error = r;
777 else if (r == DM_ENDIO_INCOMPLETE)
778 /* The target will handle the io */
779 return;
780 else if (r) {
781 DMWARN("unimplemented target endio return value: %d", r);
782 BUG();
783 }
784 }
785
786 free_tio(md, tio);
787 dec_pending(io, error);
788}
789
790/*
791 * Partial completion handling for request-based dm
792 */
793static void end_clone_bio(struct bio *clone, int error)
794{
795 struct dm_rq_clone_bio_info *info =
796 container_of(clone, struct dm_rq_clone_bio_info, clone);
797 struct dm_rq_target_io *tio = info->tio;
798 struct bio *bio = info->orig;
799 unsigned int nr_bytes = info->orig->bi_iter.bi_size;
800
801 bio_put(clone);
802
803 if (tio->error)
804 /*
805 * An error has already been detected on the request.
806 * Once error occurred, just let clone->end_io() handle
807 * the remainder.
808 */
809 return;
810 else if (error) {
811 /*
812 * Don't notice the error to the upper layer yet.
813 * The error handling decision is made by the target driver,
814 * when the request is completed.
815 */
816 tio->error = error;
817 return;
818 }
819
820 /*
821 * I/O for the bio successfully completed.
822 * Notice the data completion to the upper layer.
823 */
824
825 /*
826 * bios are processed from the head of the list.
827 * So the completing bio should always be rq->bio.
828 * If it's not, something wrong is happening.
829 */
830 if (tio->orig->bio != bio)
831 DMERR("bio completion is going in the middle of the request");
832
833 /*
834 * Update the original request.
835 * Do not use blk_end_request() here, because it may complete
836 * the original request before the clone, and break the ordering.
837 */
838 blk_update_request(tio->orig, 0, nr_bytes);
839}
840
841/*
842 * Don't touch any member of the md after calling this function because
843 * the md may be freed in dm_put() at the end of this function.
844 * Or do dm_get() before calling this function and dm_put() later.
845 */
846static void rq_completed(struct mapped_device *md, int rw, int run_queue)
847{
848 atomic_dec(&md->pending[rw]);
849
850 /* nudge anyone waiting on suspend queue */
851 if (!md_in_flight(md))
852 wake_up(&md->wait);
853
854 /*
855 * Run this off this callpath, as drivers could invoke end_io while
856 * inside their request_fn (and holding the queue lock). Calling
857 * back into ->request_fn() could deadlock attempting to grab the
858 * queue lock again.
859 */
860 if (run_queue)
861 blk_run_queue_async(md->queue);
862
863 /*
864 * dm_put() must be at the end of this function. See the comment above
865 */
866 dm_put(md);
867}
868
869static void free_rq_clone(struct request *clone)
870{
871 struct dm_rq_target_io *tio = clone->end_io_data;
872
873 blk_rq_unprep_clone(clone);
874 free_rq_tio(tio);
875}
876
877/*
878 * Complete the clone and the original request.
879 * Must be called without queue lock.
880 */
881static void dm_end_request(struct request *clone, int error)
882{
883 int rw = rq_data_dir(clone);
884 struct dm_rq_target_io *tio = clone->end_io_data;
885 struct mapped_device *md = tio->md;
886 struct request *rq = tio->orig;
887
888 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
889 rq->errors = clone->errors;
890 rq->resid_len = clone->resid_len;
891
892 if (rq->sense)
893 /*
894 * We are using the sense buffer of the original
895 * request.
896 * So setting the length of the sense data is enough.
897 */
898 rq->sense_len = clone->sense_len;
899 }
900
901 free_rq_clone(clone);
902 blk_end_request_all(rq, error);
903 rq_completed(md, rw, true);
904}
905
906static void dm_unprep_request(struct request *rq)
907{
908 struct request *clone = rq->special;
909
910 rq->special = NULL;
911 rq->cmd_flags &= ~REQ_DONTPREP;
912
913 free_rq_clone(clone);
914}
915
916/*
917 * Requeue the original request of a clone.
918 */
919void dm_requeue_unmapped_request(struct request *clone)
920{
921 int rw = rq_data_dir(clone);
922 struct dm_rq_target_io *tio = clone->end_io_data;
923 struct mapped_device *md = tio->md;
924 struct request *rq = tio->orig;
925 struct request_queue *q = rq->q;
926 unsigned long flags;
927
928 dm_unprep_request(rq);
929
930 spin_lock_irqsave(q->queue_lock, flags);
931 blk_requeue_request(q, rq);
932 spin_unlock_irqrestore(q->queue_lock, flags);
933
934 rq_completed(md, rw, 0);
935}
936EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
937
938static void __stop_queue(struct request_queue *q)
939{
940 blk_stop_queue(q);
941}
942
943static void stop_queue(struct request_queue *q)
944{
945 unsigned long flags;
946
947 spin_lock_irqsave(q->queue_lock, flags);
948 __stop_queue(q);
949 spin_unlock_irqrestore(q->queue_lock, flags);
950}
951
952static void __start_queue(struct request_queue *q)
953{
954 if (blk_queue_stopped(q))
955 blk_start_queue(q);
956}
957
958static void start_queue(struct request_queue *q)
959{
960 unsigned long flags;
961
962 spin_lock_irqsave(q->queue_lock, flags);
963 __start_queue(q);
964 spin_unlock_irqrestore(q->queue_lock, flags);
965}
966
967static void dm_done(struct request *clone, int error, bool mapped)
968{
969 int r = error;
970 struct dm_rq_target_io *tio = clone->end_io_data;
971 dm_request_endio_fn rq_end_io = NULL;
972
973 if (tio->ti) {
974 rq_end_io = tio->ti->type->rq_end_io;
975
976 if (mapped && rq_end_io)
977 r = rq_end_io(tio->ti, clone, error, &tio->info);
978 }
979
980 if (r <= 0)
981 /* The target wants to complete the I/O */
982 dm_end_request(clone, r);
983 else if (r == DM_ENDIO_INCOMPLETE)
984 /* The target will handle the I/O */
985 return;
986 else if (r == DM_ENDIO_REQUEUE)
987 /* The target wants to requeue the I/O */
988 dm_requeue_unmapped_request(clone);
989 else {
990 DMWARN("unimplemented target endio return value: %d", r);
991 BUG();
992 }
993}
994
995/*
996 * Request completion handler for request-based dm
997 */
998static void dm_softirq_done(struct request *rq)
999{
1000 bool mapped = true;
1001 struct request *clone = rq->completion_data;
1002 struct dm_rq_target_io *tio = clone->end_io_data;
1003
1004 if (rq->cmd_flags & REQ_FAILED)
1005 mapped = false;
1006
1007 dm_done(clone, tio->error, mapped);
1008}
1009
1010/*
1011 * Complete the clone and the original request with the error status
1012 * through softirq context.
1013 */
1014static void dm_complete_request(struct request *clone, int error)
1015{
1016 struct dm_rq_target_io *tio = clone->end_io_data;
1017 struct request *rq = tio->orig;
1018
1019 tio->error = error;
1020 rq->completion_data = clone;
1021 blk_complete_request(rq);
1022}
1023
1024/*
1025 * Complete the not-mapped clone and the original request with the error status
1026 * through softirq context.
1027 * Target's rq_end_io() function isn't called.
1028 * This may be used when the target's map_rq() function fails.
1029 */
1030void dm_kill_unmapped_request(struct request *clone, int error)
1031{
1032 struct dm_rq_target_io *tio = clone->end_io_data;
1033 struct request *rq = tio->orig;
1034
1035 rq->cmd_flags |= REQ_FAILED;
1036 dm_complete_request(clone, error);
1037}
1038EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
1039
1040/*
1041 * Called with the queue lock held
1042 */
1043static void end_clone_request(struct request *clone, int error)
1044{
1045 /*
1046 * For just cleaning up the information of the queue in which
1047 * the clone was dispatched.
1048 * The clone is *NOT* freed actually here because it is alloced from
1049 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
1050 */
1051 __blk_put_request(clone->q, clone);
1052
1053 /*
1054 * Actual request completion is done in a softirq context which doesn't
1055 * hold the queue lock. Otherwise, deadlock could occur because:
1056 * - another request may be submitted by the upper level driver
1057 * of the stacking during the completion
1058 * - the submission which requires queue lock may be done
1059 * against this queue
1060 */
1061 dm_complete_request(clone, error);
1062}
1063
1064/*
1065 * Return maximum size of I/O possible at the supplied sector up to the current
1066 * target boundary.
1067 */
1068static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
1069{
1070 sector_t target_offset = dm_target_offset(ti, sector);
1071
1072 return ti->len - target_offset;
1073}
1074
1075static sector_t max_io_len(sector_t sector, struct dm_target *ti)
1076{
1077 sector_t len = max_io_len_target_boundary(sector, ti);
1078 sector_t offset, max_len;
1079
1080 /*
1081 * Does the target need to split even further?
1082 */
1083 if (ti->max_io_len) {
1084 offset = dm_target_offset(ti, sector);
1085 if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
1086 max_len = sector_div(offset, ti->max_io_len);
1087 else
1088 max_len = offset & (ti->max_io_len - 1);
1089 max_len = ti->max_io_len - max_len;
1090
1091 if (len > max_len)
1092 len = max_len;
1093 }
1094
1095 return len;
1096}
1097
1098int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
1099{
1100 if (len > UINT_MAX) {
1101 DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
1102 (unsigned long long)len, UINT_MAX);
1103 ti->error = "Maximum size of target IO is too large";
1104 return -EINVAL;
1105 }
1106
1107 ti->max_io_len = (uint32_t) len;
1108
1109 return 0;
1110}
1111EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
1112
1113static void __map_bio(struct dm_target_io *tio)
1114{
1115 int r;
1116 sector_t sector;
1117 struct mapped_device *md;
1118 struct bio *clone = &tio->clone;
1119 struct dm_target *ti = tio->ti;
1120
1121 clone->bi_end_io = clone_endio;
1122
1123 /*
1124 * Map the clone. If r == 0 we don't need to do
1125 * anything, the target has assumed ownership of
1126 * this io.
1127 */
1128 atomic_inc(&tio->io->io_count);
1129 sector = clone->bi_iter.bi_sector;
1130 r = ti->type->map(ti, clone);
1131 if (r == DM_MAPIO_REMAPPED) {
1132 /* the bio has been remapped so dispatch it */
1133
1134 trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
1135 tio->io->bio->bi_bdev->bd_dev, sector);
1136
1137 generic_make_request(clone);
1138 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
1139 /* error the io and bail out, or requeue it if needed */
1140 md = tio->io->md;
1141 dec_pending(tio->io, r);
1142 free_tio(md, tio);
1143 } else if (r) {
1144 DMWARN("unimplemented target map return value: %d", r);
1145 BUG();
1146 }
1147}
1148
1149struct clone_info {
1150 struct mapped_device *md;
1151 struct dm_table *map;
1152 struct bio *bio;
1153 struct dm_io *io;
1154 sector_t sector;
1155 sector_t sector_count;
1156};
1157
1158static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len)
1159{
1160 bio->bi_iter.bi_sector = sector;
1161 bio->bi_iter.bi_size = to_bytes(len);
1162}
1163
1164/*
1165 * Creates a bio that consists of range of complete bvecs.
1166 */
1167static void clone_bio(struct dm_target_io *tio, struct bio *bio,
1168 sector_t sector, unsigned len)
1169{
1170 struct bio *clone = &tio->clone;
1171
1172 __bio_clone_fast(clone, bio);
1173
1174 if (bio_integrity(bio))
1175 bio_integrity_clone(clone, bio, GFP_NOIO);
1176
1177 bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
1178 clone->bi_iter.bi_size = to_bytes(len);
1179
1180 if (bio_integrity(bio))
1181 bio_integrity_trim(clone, 0, len);
1182}
1183
1184static struct dm_target_io *alloc_tio(struct clone_info *ci,
1185 struct dm_target *ti, int nr_iovecs,
1186 unsigned target_bio_nr)
1187{
1188 struct dm_target_io *tio;
1189 struct bio *clone;
1190
1191 clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs);
1192 tio = container_of(clone, struct dm_target_io, clone);
1193
1194 tio->io = ci->io;
1195 tio->ti = ti;
1196 tio->target_bio_nr = target_bio_nr;
1197
1198 return tio;
1199}
1200
1201static void __clone_and_map_simple_bio(struct clone_info *ci,
1202 struct dm_target *ti,
1203 unsigned target_bio_nr, sector_t len)
1204{
1205 struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
1206 struct bio *clone = &tio->clone;
1207
1208 /*
1209 * Discard requests require the bio's inline iovecs be initialized.
1210 * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
1211 * and discard, so no need for concern about wasted bvec allocations.
1212 */
1213 __bio_clone_fast(clone, ci->bio);
1214 if (len)
1215 bio_setup_sector(clone, ci->sector, len);
1216
1217 __map_bio(tio);
1218}
1219
1220static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
1221 unsigned num_bios, sector_t len)
1222{
1223 unsigned target_bio_nr;
1224
1225 for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
1226 __clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
1227}
1228
1229static int __send_empty_flush(struct clone_info *ci)
1230{
1231 unsigned target_nr = 0;
1232 struct dm_target *ti;
1233
1234 BUG_ON(bio_has_data(ci->bio));
1235 while ((ti = dm_table_get_target(ci->map, target_nr++)))
1236 __send_duplicate_bios(ci, ti, ti->num_flush_bios, 0);
1237
1238 return 0;
1239}
1240
1241static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
1242 sector_t sector, unsigned len)
1243{
1244 struct bio *bio = ci->bio;
1245 struct dm_target_io *tio;
1246 unsigned target_bio_nr;
1247 unsigned num_target_bios = 1;
1248
1249 /*
1250 * Does the target want to receive duplicate copies of the bio?
1251 */
1252 if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
1253 num_target_bios = ti->num_write_bios(ti, bio);
1254
1255 for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
1256 tio = alloc_tio(ci, ti, 0, target_bio_nr);
1257 clone_bio(tio, bio, sector, len);
1258 __map_bio(tio);
1259 }
1260}
1261
1262typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
1263
1264static unsigned get_num_discard_bios(struct dm_target *ti)
1265{
1266 return ti->num_discard_bios;
1267}
1268
1269static unsigned get_num_write_same_bios(struct dm_target *ti)
1270{
1271 return ti->num_write_same_bios;
1272}
1273
1274typedef bool (*is_split_required_fn)(struct dm_target *ti);
1275
1276static bool is_split_required_for_discard(struct dm_target *ti)
1277{
1278 return ti->split_discard_bios;
1279}
1280
1281static int __send_changing_extent_only(struct clone_info *ci,
1282 get_num_bios_fn get_num_bios,
1283 is_split_required_fn is_split_required)
1284{
1285 struct dm_target *ti;
1286 sector_t len;
1287 unsigned num_bios;
1288
1289 do {
1290 ti = dm_table_find_target(ci->map, ci->sector);
1291 if (!dm_target_is_valid(ti))
1292 return -EIO;
1293
1294 /*
1295 * Even though the device advertised support for this type of
1296 * request, that does not mean every target supports it, and
1297 * reconfiguration might also have changed that since the
1298 * check was performed.
1299 */
1300 num_bios = get_num_bios ? get_num_bios(ti) : 0;
1301 if (!num_bios)
1302 return -EOPNOTSUPP;
1303
1304 if (is_split_required && !is_split_required(ti))
1305 len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
1306 else
1307 len = min(ci->sector_count, max_io_len(ci->sector, ti));
1308
1309 __send_duplicate_bios(ci, ti, num_bios, len);
1310
1311 ci->sector += len;
1312 } while (ci->sector_count -= len);
1313
1314 return 0;
1315}
1316
1317static int __send_discard(struct clone_info *ci)
1318{
1319 return __send_changing_extent_only(ci, get_num_discard_bios,
1320 is_split_required_for_discard);
1321}
1322
1323static int __send_write_same(struct clone_info *ci)
1324{
1325 return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
1326}
1327
1328/*
1329 * Select the correct strategy for processing a non-flush bio.
1330 */
1331static int __split_and_process_non_flush(struct clone_info *ci)
1332{
1333 struct bio *bio = ci->bio;
1334 struct dm_target *ti;
1335 unsigned len;
1336
1337 if (unlikely(bio->bi_rw & REQ_DISCARD))
1338 return __send_discard(ci);
1339 else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
1340 return __send_write_same(ci);
1341
1342 ti = dm_table_find_target(ci->map, ci->sector);
1343 if (!dm_target_is_valid(ti))
1344 return -EIO;
1345
1346 len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
1347
1348 __clone_and_map_data_bio(ci, ti, ci->sector, len);
1349
1350 ci->sector += len;
1351 ci->sector_count -= len;
1352
1353 return 0;
1354}
1355
1356/*
1357 * Entry point to split a bio into clones and submit them to the targets.
1358 */
1359static void __split_and_process_bio(struct mapped_device *md,
1360 struct dm_table *map, struct bio *bio)
1361{
1362 struct clone_info ci;
1363 int error = 0;
1364
1365 if (unlikely(!map)) {
1366 bio_io_error(bio);
1367 return;
1368 }
1369
1370 ci.map = map;
1371 ci.md = md;
1372 ci.io = alloc_io(md);
1373 ci.io->error = 0;
1374 atomic_set(&ci.io->io_count, 1);
1375 ci.io->bio = bio;
1376 ci.io->md = md;
1377 spin_lock_init(&ci.io->endio_lock);
1378 ci.sector = bio->bi_iter.bi_sector;
1379
1380 start_io_acct(ci.io);
1381
1382 if (bio->bi_rw & REQ_FLUSH) {
1383 ci.bio = &ci.md->flush_bio;
1384 ci.sector_count = 0;
1385 error = __send_empty_flush(&ci);
1386 /* dec_pending submits any data associated with flush */
1387 } else {
1388 ci.bio = bio;
1389 ci.sector_count = bio_sectors(bio);
1390 while (ci.sector_count && !error)
1391 error = __split_and_process_non_flush(&ci);
1392 }
1393
1394 /* drop the extra reference count */
1395 dec_pending(ci.io, error);
1396}
1397/*-----------------------------------------------------------------
1398 * CRUD END
1399 *---------------------------------------------------------------*/
1400
1401static int dm_merge_bvec(struct request_queue *q,
1402 struct bvec_merge_data *bvm,
1403 struct bio_vec *biovec)
1404{
1405 struct mapped_device *md = q->queuedata;
1406 struct dm_table *map = dm_get_live_table_fast(md);
1407 struct dm_target *ti;
1408 sector_t max_sectors;
1409 int max_size = 0;
1410
1411 if (unlikely(!map))
1412 goto out;
1413
1414 ti = dm_table_find_target(map, bvm->bi_sector);
1415 if (!dm_target_is_valid(ti))
1416 goto out;
1417
1418 /*
1419 * Find maximum amount of I/O that won't need splitting
1420 */
1421 max_sectors = min(max_io_len(bvm->bi_sector, ti),
1422 (sector_t) BIO_MAX_SECTORS);
1423 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
1424 if (max_size < 0)
1425 max_size = 0;
1426
1427 /*
1428 * merge_bvec_fn() returns number of bytes
1429 * it can accept at this offset
1430 * max is precomputed maximal io size
1431 */
1432 if (max_size && ti->type->merge)
1433 max_size = ti->type->merge(ti, bvm, biovec, max_size);
1434 /*
1435 * If the target doesn't support merge method and some of the devices
1436 * provided their merge_bvec method (we know this by looking at
1437 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1438 * entries. So always set max_size to 0, and the code below allows
1439 * just one page.
1440 */
1441 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
1442
1443 max_size = 0;
1444
1445out:
1446 dm_put_live_table_fast(md);
1447 /*
1448 * Always allow an entire first page
1449 */
1450 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
1451 max_size = biovec->bv_len;
1452
1453 return max_size;
1454}
1455
1456/*
1457 * The request function that just remaps the bio built up by
1458 * dm_merge_bvec.
1459 */
1460static void _dm_request(struct request_queue *q, struct bio *bio)
1461{
1462 int rw = bio_data_dir(bio);
1463 struct mapped_device *md = q->queuedata;
1464 int cpu;
1465 int srcu_idx;
1466 struct dm_table *map;
1467
1468 map = dm_get_live_table(md, &srcu_idx);
1469
1470 cpu = part_stat_lock();
1471 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
1472 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
1473 part_stat_unlock();
1474
1475 /* if we're suspended, we have to queue this io for later */
1476 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
1477 dm_put_live_table(md, srcu_idx);
1478
1479 if (bio_rw(bio) != READA)
1480 queue_io(md, bio);
1481 else
1482 bio_io_error(bio);
1483 return;
1484 }
1485
1486 __split_and_process_bio(md, map, bio);
1487 dm_put_live_table(md, srcu_idx);
1488 return;
1489}
1490
1491int dm_request_based(struct mapped_device *md)
1492{
1493 return blk_queue_stackable(md->queue);
1494}
1495
1496static void dm_request(struct request_queue *q, struct bio *bio)
1497{
1498 struct mapped_device *md = q->queuedata;
1499
1500 if (dm_request_based(md))
1501 blk_queue_bio(q, bio);
1502 else
1503 _dm_request(q, bio);
1504}
1505
1506void dm_dispatch_request(struct request *rq)
1507{
1508 int r;
1509
1510 if (blk_queue_io_stat(rq->q))
1511 rq->cmd_flags |= REQ_IO_STAT;
1512
1513 rq->start_time = jiffies;
1514 r = blk_insert_cloned_request(rq->q, rq);
1515 if (r)
1516 dm_complete_request(rq, r);
1517}
1518EXPORT_SYMBOL_GPL(dm_dispatch_request);
1519
1520static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
1521 void *data)
1522{
1523 struct dm_rq_target_io *tio = data;
1524 struct dm_rq_clone_bio_info *info =
1525 container_of(bio, struct dm_rq_clone_bio_info, clone);
1526
1527 info->orig = bio_orig;
1528 info->tio = tio;
1529 bio->bi_end_io = end_clone_bio;
1530
1531 return 0;
1532}
1533
1534static int setup_clone(struct request *clone, struct request *rq,
1535 struct dm_rq_target_io *tio)
1536{
1537 int r;
1538
1539 r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
1540 dm_rq_bio_constructor, tio);
1541 if (r)
1542 return r;
1543
1544 clone->cmd = rq->cmd;
1545 clone->cmd_len = rq->cmd_len;
1546 clone->sense = rq->sense;
1547 clone->buffer = rq->buffer;
1548 clone->end_io = end_clone_request;
1549 clone->end_io_data = tio;
1550
1551 return 0;
1552}
1553
1554static struct request *clone_rq(struct request *rq, struct mapped_device *md,
1555 gfp_t gfp_mask)
1556{
1557 struct request *clone;
1558 struct dm_rq_target_io *tio;
1559
1560 tio = alloc_rq_tio(md, gfp_mask);
1561 if (!tio)
1562 return NULL;
1563
1564 tio->md = md;
1565 tio->ti = NULL;
1566 tio->orig = rq;
1567 tio->error = 0;
1568 memset(&tio->info, 0, sizeof(tio->info));
1569
1570 clone = &tio->clone;
1571 if (setup_clone(clone, rq, tio)) {
1572 /* -ENOMEM */
1573 free_rq_tio(tio);
1574 return NULL;
1575 }
1576
1577 return clone;
1578}
1579
1580/*
1581 * Called with the queue lock held.
1582 */
1583static int dm_prep_fn(struct request_queue *q, struct request *rq)
1584{
1585 struct mapped_device *md = q->queuedata;
1586 struct request *clone;
1587
1588 if (unlikely(rq->special)) {
1589 DMWARN("Already has something in rq->special.");
1590 return BLKPREP_KILL;
1591 }
1592
1593 clone = clone_rq(rq, md, GFP_ATOMIC);
1594 if (!clone)
1595 return BLKPREP_DEFER;
1596
1597 rq->special = clone;
1598 rq->cmd_flags |= REQ_DONTPREP;
1599
1600 return BLKPREP_OK;
1601}
1602
1603/*
1604 * Returns:
1605 * 0 : the request has been processed (not requeued)
1606 * !0 : the request has been requeued
1607 */
1608static int map_request(struct dm_target *ti, struct request *clone,
1609 struct mapped_device *md)
1610{
1611 int r, requeued = 0;
1612 struct dm_rq_target_io *tio = clone->end_io_data;
1613
1614 tio->ti = ti;
1615 r = ti->type->map_rq(ti, clone, &tio->info);
1616 switch (r) {
1617 case DM_MAPIO_SUBMITTED:
1618 /* The target has taken the I/O to submit by itself later */
1619 break;
1620 case DM_MAPIO_REMAPPED:
1621 /* The target has remapped the I/O so dispatch it */
1622 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
1623 blk_rq_pos(tio->orig));
1624 dm_dispatch_request(clone);
1625 break;
1626 case DM_MAPIO_REQUEUE:
1627 /* The target wants to requeue the I/O */
1628 dm_requeue_unmapped_request(clone);
1629 requeued = 1;
1630 break;
1631 default:
1632 if (r > 0) {
1633 DMWARN("unimplemented target map return value: %d", r);
1634 BUG();
1635 }
1636
1637 /* The target wants to complete the I/O */
1638 dm_kill_unmapped_request(clone, r);
1639 break;
1640 }
1641
1642 return requeued;
1643}
1644
1645static struct request *dm_start_request(struct mapped_device *md, struct request *orig)
1646{
1647 struct request *clone;
1648
1649 blk_start_request(orig);
1650 clone = orig->special;
1651 atomic_inc(&md->pending[rq_data_dir(clone)]);
1652
1653 /*
1654 * Hold the md reference here for the in-flight I/O.
1655 * We can't rely on the reference count by device opener,
1656 * because the device may be closed during the request completion
1657 * when all bios are completed.
1658 * See the comment in rq_completed() too.
1659 */
1660 dm_get(md);
1661
1662 return clone;
1663}
1664
1665/*
1666 * q->request_fn for request-based dm.
1667 * Called with the queue lock held.
1668 */
1669static void dm_request_fn(struct request_queue *q)
1670{
1671 struct mapped_device *md = q->queuedata;
1672 int srcu_idx;
1673 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
1674 struct dm_target *ti;
1675 struct request *rq, *clone;
1676 sector_t pos;
1677
1678 /*
1679 * For suspend, check blk_queue_stopped() and increment
1680 * ->pending within a single queue_lock not to increment the
1681 * number of in-flight I/Os after the queue is stopped in
1682 * dm_suspend().
1683 */
1684 while (!blk_queue_stopped(q)) {
1685 rq = blk_peek_request(q);
1686 if (!rq)
1687 goto delay_and_out;
1688
1689 /* always use block 0 to find the target for flushes for now */
1690 pos = 0;
1691 if (!(rq->cmd_flags & REQ_FLUSH))
1692 pos = blk_rq_pos(rq);
1693
1694 ti = dm_table_find_target(map, pos);
1695 if (!dm_target_is_valid(ti)) {
1696 /*
1697 * Must perform setup, that dm_done() requires,
1698 * before calling dm_kill_unmapped_request
1699 */
1700 DMERR_LIMIT("request attempted access beyond the end of device");
1701 clone = dm_start_request(md, rq);
1702 dm_kill_unmapped_request(clone, -EIO);
1703 continue;
1704 }
1705
1706 if (ti->type->busy && ti->type->busy(ti))
1707 goto delay_and_out;
1708
1709 clone = dm_start_request(md, rq);
1710
1711 spin_unlock(q->queue_lock);
1712 if (map_request(ti, clone, md))
1713 goto requeued;
1714
1715 BUG_ON(!irqs_disabled());
1716 spin_lock(q->queue_lock);
1717 }
1718
1719 goto out;
1720
1721requeued:
1722 BUG_ON(!irqs_disabled());
1723 spin_lock(q->queue_lock);
1724
1725delay_and_out:
1726 blk_delay_queue(q, HZ / 10);
1727out:
1728 dm_put_live_table(md, srcu_idx);
1729}
1730
1731int dm_underlying_device_busy(struct request_queue *q)
1732{
1733 return blk_lld_busy(q);
1734}
1735EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
1736
1737static int dm_lld_busy(struct request_queue *q)
1738{
1739 int r;
1740 struct mapped_device *md = q->queuedata;
1741 struct dm_table *map = dm_get_live_table_fast(md);
1742
1743 if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
1744 r = 1;
1745 else
1746 r = dm_table_any_busy_target(map);
1747
1748 dm_put_live_table_fast(md);
1749
1750 return r;
1751}
1752
1753static int dm_any_congested(void *congested_data, int bdi_bits)
1754{
1755 int r = bdi_bits;
1756 struct mapped_device *md = congested_data;
1757 struct dm_table *map;
1758
1759 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
1760 map = dm_get_live_table_fast(md);
1761 if (map) {
1762 /*
1763 * Request-based dm cares about only own queue for
1764 * the query about congestion status of request_queue
1765 */
1766 if (dm_request_based(md))
1767 r = md->queue->backing_dev_info.state &
1768 bdi_bits;
1769 else
1770 r = dm_table_any_congested(map, bdi_bits);
1771 }
1772 dm_put_live_table_fast(md);
1773 }
1774
1775 return r;
1776}
1777
1778/*-----------------------------------------------------------------
1779 * An IDR is used to keep track of allocated minor numbers.
1780 *---------------------------------------------------------------*/
1781static void free_minor(int minor)
1782{
1783 spin_lock(&_minor_lock);
1784 idr_remove(&_minor_idr, minor);
1785 spin_unlock(&_minor_lock);
1786}
1787
1788/*
1789 * See if the device with a specific minor # is free.
1790 */
1791static int specific_minor(int minor)
1792{
1793 int r;
1794
1795 if (minor >= (1 << MINORBITS))
1796 return -EINVAL;
1797
1798 idr_preload(GFP_KERNEL);
1799 spin_lock(&_minor_lock);
1800
1801 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
1802
1803 spin_unlock(&_minor_lock);
1804 idr_preload_end();
1805 if (r < 0)
1806 return r == -ENOSPC ? -EBUSY : r;
1807 return 0;
1808}
1809
1810static int next_free_minor(int *minor)
1811{
1812 int r;
1813
1814 idr_preload(GFP_KERNEL);
1815 spin_lock(&_minor_lock);
1816
1817 r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
1818
1819 spin_unlock(&_minor_lock);
1820 idr_preload_end();
1821 if (r < 0)
1822 return r;
1823 *minor = r;
1824 return 0;
1825}
1826
1827static const struct block_device_operations dm_blk_dops;
1828
1829static void dm_wq_work(struct work_struct *work);
1830
1831static void dm_init_md_queue(struct mapped_device *md)
1832{
1833 /*
1834 * Request-based dm devices cannot be stacked on top of bio-based dm
1835 * devices. The type of this dm device has not been decided yet.
1836 * The type is decided at the first table loading time.
1837 * To prevent problematic device stacking, clear the queue flag
1838 * for request stacking support until then.
1839 *
1840 * This queue is new, so no concurrency on the queue_flags.
1841 */
1842 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
1843
1844 md->queue->queuedata = md;
1845 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1846 md->queue->backing_dev_info.congested_data = md;
1847 blk_queue_make_request(md->queue, dm_request);
1848 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1849 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1850}
1851
1852/*
1853 * Allocate and initialise a blank device with a given minor.
1854 */
1855static struct mapped_device *alloc_dev(int minor)
1856{
1857 int r;
1858 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1859 void *old_md;
1860
1861 if (!md) {
1862 DMWARN("unable to allocate device, out of memory.");
1863 return NULL;
1864 }
1865
1866 if (!try_module_get(THIS_MODULE))
1867 goto bad_module_get;
1868
1869 /* get a minor number for the dev */
1870 if (minor == DM_ANY_MINOR)
1871 r = next_free_minor(&minor);
1872 else
1873 r = specific_minor(minor);
1874 if (r < 0)
1875 goto bad_minor;
1876
1877 r = init_srcu_struct(&md->io_barrier);
1878 if (r < 0)
1879 goto bad_io_barrier;
1880
1881 md->type = DM_TYPE_NONE;
1882 mutex_init(&md->suspend_lock);
1883 mutex_init(&md->type_lock);
1884 spin_lock_init(&md->deferred_lock);
1885 atomic_set(&md->holders, 1);
1886 atomic_set(&md->open_count, 0);
1887 atomic_set(&md->event_nr, 0);
1888 atomic_set(&md->uevent_seq, 0);
1889 INIT_LIST_HEAD(&md->uevent_list);
1890 spin_lock_init(&md->uevent_lock);
1891
1892 md->queue = blk_alloc_queue(GFP_KERNEL);
1893 if (!md->queue)
1894 goto bad_queue;
1895
1896 dm_init_md_queue(md);
1897
1898 md->disk = alloc_disk(1);
1899 if (!md->disk)
1900 goto bad_disk;
1901
1902 atomic_set(&md->pending[0], 0);
1903 atomic_set(&md->pending[1], 0);
1904 init_waitqueue_head(&md->wait);
1905 INIT_WORK(&md->work, dm_wq_work);
1906 init_waitqueue_head(&md->eventq);
1907 init_completion(&md->kobj_holder.completion);
1908
1909 md->disk->major = _major;
1910 md->disk->first_minor = minor;
1911 md->disk->fops = &dm_blk_dops;
1912 md->disk->queue = md->queue;
1913 md->disk->private_data = md;
1914 sprintf(md->disk->disk_name, "dm-%d", minor);
1915 add_disk(md->disk);
1916 format_dev_t(md->name, MKDEV(_major, minor));
1917
1918 md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
1919 if (!md->wq)
1920 goto bad_thread;
1921
1922 md->bdev = bdget_disk(md->disk, 0);
1923 if (!md->bdev)
1924 goto bad_bdev;
1925
1926 bio_init(&md->flush_bio);
1927 md->flush_bio.bi_bdev = md->bdev;
1928 md->flush_bio.bi_rw = WRITE_FLUSH;
1929
1930 dm_stats_init(&md->stats);
1931
1932 /* Populate the mapping, nobody knows we exist yet */
1933 spin_lock(&_minor_lock);
1934 old_md = idr_replace(&_minor_idr, md, minor);
1935 spin_unlock(&_minor_lock);
1936
1937 BUG_ON(old_md != MINOR_ALLOCED);
1938
1939 return md;
1940
1941bad_bdev:
1942 destroy_workqueue(md->wq);
1943bad_thread:
1944 del_gendisk(md->disk);
1945 put_disk(md->disk);
1946bad_disk:
1947 blk_cleanup_queue(md->queue);
1948bad_queue:
1949 cleanup_srcu_struct(&md->io_barrier);
1950bad_io_barrier:
1951 free_minor(minor);
1952bad_minor:
1953 module_put(THIS_MODULE);
1954bad_module_get:
1955 kfree(md);
1956 return NULL;
1957}
1958
1959static void unlock_fs(struct mapped_device *md);
1960
1961static void free_dev(struct mapped_device *md)
1962{
1963 int minor = MINOR(disk_devt(md->disk));
1964
1965 unlock_fs(md);
1966 bdput(md->bdev);
1967 destroy_workqueue(md->wq);
1968 if (md->io_pool)
1969 mempool_destroy(md->io_pool);
1970 if (md->bs)
1971 bioset_free(md->bs);
1972 blk_integrity_unregister(md->disk);
1973 del_gendisk(md->disk);
1974 cleanup_srcu_struct(&md->io_barrier);
1975 free_minor(minor);
1976
1977 spin_lock(&_minor_lock);
1978 md->disk->private_data = NULL;
1979 spin_unlock(&_minor_lock);
1980
1981 put_disk(md->disk);
1982 blk_cleanup_queue(md->queue);
1983 dm_stats_cleanup(&md->stats);
1984 module_put(THIS_MODULE);
1985 kfree(md);
1986}
1987
1988static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
1989{
1990 struct dm_md_mempools *p = dm_table_get_md_mempools(t);
1991
1992 if (md->io_pool && md->bs) {
1993 /* The md already has necessary mempools. */
1994 if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
1995 /*
1996 * Reload bioset because front_pad may have changed
1997 * because a different table was loaded.
1998 */
1999 bioset_free(md->bs);
2000 md->bs = p->bs;
2001 p->bs = NULL;
2002 } else if (dm_table_get_type(t) == DM_TYPE_REQUEST_BASED) {
2003 /*
2004 * There's no need to reload with request-based dm
2005 * because the size of front_pad doesn't change.
2006 * Note for future: If you are to reload bioset,
2007 * prep-ed requests in the queue may refer
2008 * to bio from the old bioset, so you must walk
2009 * through the queue to unprep.
2010 */
2011 }
2012 goto out;
2013 }
2014
2015 BUG_ON(!p || md->io_pool || md->bs);
2016
2017 md->io_pool = p->io_pool;
2018 p->io_pool = NULL;
2019 md->bs = p->bs;
2020 p->bs = NULL;
2021
2022out:
2023 /* mempool bind completed, now no need any mempools in the table */
2024 dm_table_free_md_mempools(t);
2025}
2026
2027/*
2028 * Bind a table to the device.
2029 */
2030static void event_callback(void *context)
2031{
2032 unsigned long flags;
2033 LIST_HEAD(uevents);
2034 struct mapped_device *md = (struct mapped_device *) context;
2035
2036 spin_lock_irqsave(&md->uevent_lock, flags);
2037 list_splice_init(&md->uevent_list, &uevents);
2038 spin_unlock_irqrestore(&md->uevent_lock, flags);
2039
2040 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
2041
2042 atomic_inc(&md->event_nr);
2043 wake_up(&md->eventq);
2044}
2045
2046/*
2047 * Protected by md->suspend_lock obtained by dm_swap_table().
2048 */
2049static void __set_size(struct mapped_device *md, sector_t size)
2050{
2051 set_capacity(md->disk, size);
2052
2053 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
2054}
2055
2056/*
2057 * Return 1 if the queue has a compulsory merge_bvec_fn function.
2058 *
2059 * If this function returns 0, then the device is either a non-dm
2060 * device without a merge_bvec_fn, or it is a dm device that is
2061 * able to split any bios it receives that are too big.
2062 */
2063int dm_queue_merge_is_compulsory(struct request_queue *q)
2064{
2065 struct mapped_device *dev_md;
2066
2067 if (!q->merge_bvec_fn)
2068 return 0;
2069
2070 if (q->make_request_fn == dm_request) {
2071 dev_md = q->queuedata;
2072 if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
2073 return 0;
2074 }
2075
2076 return 1;
2077}
2078
2079static int dm_device_merge_is_compulsory(struct dm_target *ti,
2080 struct dm_dev *dev, sector_t start,
2081 sector_t len, void *data)
2082{
2083 struct block_device *bdev = dev->bdev;
2084 struct request_queue *q = bdev_get_queue(bdev);
2085
2086 return dm_queue_merge_is_compulsory(q);
2087}
2088
2089/*
2090 * Return 1 if it is acceptable to ignore merge_bvec_fn based
2091 * on the properties of the underlying devices.
2092 */
2093static int dm_table_merge_is_optional(struct dm_table *table)
2094{
2095 unsigned i = 0;
2096 struct dm_target *ti;
2097
2098 while (i < dm_table_get_num_targets(table)) {
2099 ti = dm_table_get_target(table, i++);
2100
2101 if (ti->type->iterate_devices &&
2102 ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
2103 return 0;
2104 }
2105
2106 return 1;
2107}
2108
2109/*
2110 * Returns old map, which caller must destroy.
2111 */
2112static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
2113 struct queue_limits *limits)
2114{
2115 struct dm_table *old_map;
2116 struct request_queue *q = md->queue;
2117 sector_t size;
2118 int merge_is_optional;
2119
2120 size = dm_table_get_size(t);
2121
2122 /*
2123 * Wipe any geometry if the size of the table changed.
2124 */
2125 if (size != dm_get_size(md))
2126 memset(&md->geometry, 0, sizeof(md->geometry));
2127
2128 __set_size(md, size);
2129
2130 dm_table_event_callback(t, event_callback, md);
2131
2132 /*
2133 * The queue hasn't been stopped yet, if the old table type wasn't
2134 * for request-based during suspension. So stop it to prevent
2135 * I/O mapping before resume.
2136 * This must be done before setting the queue restrictions,
2137 * because request-based dm may be run just after the setting.
2138 */
2139 if (dm_table_request_based(t) && !blk_queue_stopped(q))
2140 stop_queue(q);
2141
2142 __bind_mempools(md, t);
2143
2144 merge_is_optional = dm_table_merge_is_optional(t);
2145
2146 old_map = md->map;
2147 rcu_assign_pointer(md->map, t);
2148 md->immutable_target_type = dm_table_get_immutable_target_type(t);
2149
2150 dm_table_set_restrictions(t, q, limits);
2151 if (merge_is_optional)
2152 set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2153 else
2154 clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2155 dm_sync_table(md);
2156
2157 return old_map;
2158}
2159
2160/*
2161 * Returns unbound table for the caller to free.
2162 */
2163static struct dm_table *__unbind(struct mapped_device *md)
2164{
2165 struct dm_table *map = md->map;
2166
2167 if (!map)
2168 return NULL;
2169
2170 dm_table_event_callback(map, NULL, NULL);
2171 RCU_INIT_POINTER(md->map, NULL);
2172 dm_sync_table(md);
2173
2174 return map;
2175}
2176
2177/*
2178 * Constructor for a new device.
2179 */
2180int dm_create(int minor, struct mapped_device **result)
2181{
2182 struct mapped_device *md;
2183
2184 md = alloc_dev(minor);
2185 if (!md)
2186 return -ENXIO;
2187
2188 dm_sysfs_init(md);
2189
2190 *result = md;
2191 return 0;
2192}
2193
2194/*
2195 * Functions to manage md->type.
2196 * All are required to hold md->type_lock.
2197 */
2198void dm_lock_md_type(struct mapped_device *md)
2199{
2200 mutex_lock(&md->type_lock);
2201}
2202
2203void dm_unlock_md_type(struct mapped_device *md)
2204{
2205 mutex_unlock(&md->type_lock);
2206}
2207
2208void dm_set_md_type(struct mapped_device *md, unsigned type)
2209{
2210 BUG_ON(!mutex_is_locked(&md->type_lock));
2211 md->type = type;
2212}
2213
2214unsigned dm_get_md_type(struct mapped_device *md)
2215{
2216 BUG_ON(!mutex_is_locked(&md->type_lock));
2217 return md->type;
2218}
2219
2220struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
2221{
2222 return md->immutable_target_type;
2223}
2224
2225/*
2226 * The queue_limits are only valid as long as you have a reference
2227 * count on 'md'.
2228 */
2229struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
2230{
2231 BUG_ON(!atomic_read(&md->holders));
2232 return &md->queue->limits;
2233}
2234EXPORT_SYMBOL_GPL(dm_get_queue_limits);
2235
2236/*
2237 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2238 */
2239static int dm_init_request_based_queue(struct mapped_device *md)
2240{
2241 struct request_queue *q = NULL;
2242
2243 if (md->queue->elevator)
2244 return 1;
2245
2246 /* Fully initialize the queue */
2247 q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
2248 if (!q)
2249 return 0;
2250
2251 md->queue = q;
2252 dm_init_md_queue(md);
2253 blk_queue_softirq_done(md->queue, dm_softirq_done);
2254 blk_queue_prep_rq(md->queue, dm_prep_fn);
2255 blk_queue_lld_busy(md->queue, dm_lld_busy);
2256
2257 elv_register_queue(md->queue);
2258
2259 return 1;
2260}
2261
2262/*
2263 * Setup the DM device's queue based on md's type
2264 */
2265int dm_setup_md_queue(struct mapped_device *md)
2266{
2267 if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) &&
2268 !dm_init_request_based_queue(md)) {
2269 DMWARN("Cannot initialize queue for request-based mapped device");
2270 return -EINVAL;
2271 }
2272
2273 return 0;
2274}
2275
2276static struct mapped_device *dm_find_md(dev_t dev)
2277{
2278 struct mapped_device *md;
2279 unsigned minor = MINOR(dev);
2280
2281 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2282 return NULL;
2283
2284 spin_lock(&_minor_lock);
2285
2286 md = idr_find(&_minor_idr, minor);
2287 if (md && (md == MINOR_ALLOCED ||
2288 (MINOR(disk_devt(dm_disk(md))) != minor) ||
2289 dm_deleting_md(md) ||
2290 test_bit(DMF_FREEING, &md->flags))) {
2291 md = NULL;
2292 goto out;
2293 }
2294
2295out:
2296 spin_unlock(&_minor_lock);
2297
2298 return md;
2299}
2300
2301struct mapped_device *dm_get_md(dev_t dev)
2302{
2303 struct mapped_device *md = dm_find_md(dev);
2304
2305 if (md)
2306 dm_get(md);
2307
2308 return md;
2309}
2310EXPORT_SYMBOL_GPL(dm_get_md);
2311
2312void *dm_get_mdptr(struct mapped_device *md)
2313{
2314 return md->interface_ptr;
2315}
2316
2317void dm_set_mdptr(struct mapped_device *md, void *ptr)
2318{
2319 md->interface_ptr = ptr;
2320}
2321
2322void dm_get(struct mapped_device *md)
2323{
2324 atomic_inc(&md->holders);
2325 BUG_ON(test_bit(DMF_FREEING, &md->flags));
2326}
2327
2328const char *dm_device_name(struct mapped_device *md)
2329{
2330 return md->name;
2331}
2332EXPORT_SYMBOL_GPL(dm_device_name);
2333
2334static void __dm_destroy(struct mapped_device *md, bool wait)
2335{
2336 struct dm_table *map;
2337 int srcu_idx;
2338
2339 might_sleep();
2340
2341 spin_lock(&_minor_lock);
2342 map = dm_get_live_table(md, &srcu_idx);
2343 idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
2344 set_bit(DMF_FREEING, &md->flags);
2345 spin_unlock(&_minor_lock);
2346
2347 if (!dm_suspended_md(md)) {
2348 dm_table_presuspend_targets(map);
2349 dm_table_postsuspend_targets(map);
2350 }
2351
2352 /* dm_put_live_table must be before msleep, otherwise deadlock is possible */
2353 dm_put_live_table(md, srcu_idx);
2354
2355 /*
2356 * Rare, but there may be I/O requests still going to complete,
2357 * for example. Wait for all references to disappear.
2358 * No one should increment the reference count of the mapped_device,
2359 * after the mapped_device state becomes DMF_FREEING.
2360 */
2361 if (wait)
2362 while (atomic_read(&md->holders))
2363 msleep(1);
2364 else if (atomic_read(&md->holders))
2365 DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2366 dm_device_name(md), atomic_read(&md->holders));
2367
2368 dm_sysfs_exit(md);
2369 dm_table_destroy(__unbind(md));
2370 free_dev(md);
2371}
2372
2373void dm_destroy(struct mapped_device *md)
2374{
2375 __dm_destroy(md, true);
2376}
2377
2378void dm_destroy_immediate(struct mapped_device *md)
2379{
2380 __dm_destroy(md, false);
2381}
2382
2383void dm_put(struct mapped_device *md)
2384{
2385 atomic_dec(&md->holders);
2386}
2387EXPORT_SYMBOL_GPL(dm_put);
2388
2389static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2390{
2391 int r = 0;
2392 DECLARE_WAITQUEUE(wait, current);
2393
2394 add_wait_queue(&md->wait, &wait);
2395
2396 while (1) {
2397 set_current_state(interruptible);
2398
2399 if (!md_in_flight(md))
2400 break;
2401
2402 if (interruptible == TASK_INTERRUPTIBLE &&
2403 signal_pending(current)) {
2404 r = -EINTR;
2405 break;
2406 }
2407
2408 io_schedule();
2409 }
2410 set_current_state(TASK_RUNNING);
2411
2412 remove_wait_queue(&md->wait, &wait);
2413
2414 return r;
2415}
2416
2417/*
2418 * Process the deferred bios
2419 */
2420static void dm_wq_work(struct work_struct *work)
2421{
2422 struct mapped_device *md = container_of(work, struct mapped_device,
2423 work);
2424 struct bio *c;
2425 int srcu_idx;
2426 struct dm_table *map;
2427
2428 map = dm_get_live_table(md, &srcu_idx);
2429
2430 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2431 spin_lock_irq(&md->deferred_lock);
2432 c = bio_list_pop(&md->deferred);
2433 spin_unlock_irq(&md->deferred_lock);
2434
2435 if (!c)
2436 break;
2437
2438 if (dm_request_based(md))
2439 generic_make_request(c);
2440 else
2441 __split_and_process_bio(md, map, c);
2442 }
2443
2444 dm_put_live_table(md, srcu_idx);
2445}
2446
2447static void dm_queue_flush(struct mapped_device *md)
2448{
2449 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2450 smp_mb__after_clear_bit();
2451 queue_work(md->wq, &md->work);
2452}
2453
2454/*
2455 * Swap in a new table, returning the old one for the caller to destroy.
2456 */
2457struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
2458{
2459 struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
2460 struct queue_limits limits;
2461 int r;
2462
2463 mutex_lock(&md->suspend_lock);
2464
2465 /* device must be suspended */
2466 if (!dm_suspended_md(md))
2467 goto out;
2468
2469 /*
2470 * If the new table has no data devices, retain the existing limits.
2471 * This helps multipath with queue_if_no_path if all paths disappear,
2472 * then new I/O is queued based on these limits, and then some paths
2473 * reappear.
2474 */
2475 if (dm_table_has_no_data_devices(table)) {
2476 live_map = dm_get_live_table_fast(md);
2477 if (live_map)
2478 limits = md->queue->limits;
2479 dm_put_live_table_fast(md);
2480 }
2481
2482 if (!live_map) {
2483 r = dm_calculate_queue_limits(table, &limits);
2484 if (r) {
2485 map = ERR_PTR(r);
2486 goto out;
2487 }
2488 }
2489
2490 map = __bind(md, table, &limits);
2491
2492out:
2493 mutex_unlock(&md->suspend_lock);
2494 return map;
2495}
2496
2497/*
2498 * Functions to lock and unlock any filesystem running on the
2499 * device.
2500 */
2501static int lock_fs(struct mapped_device *md)
2502{
2503 int r;
2504
2505 WARN_ON(md->frozen_sb);
2506
2507 md->frozen_sb = freeze_bdev(md->bdev);
2508 if (IS_ERR(md->frozen_sb)) {
2509 r = PTR_ERR(md->frozen_sb);
2510 md->frozen_sb = NULL;
2511 return r;
2512 }
2513
2514 set_bit(DMF_FROZEN, &md->flags);
2515
2516 return 0;
2517}
2518
2519static void unlock_fs(struct mapped_device *md)
2520{
2521 if (!test_bit(DMF_FROZEN, &md->flags))
2522 return;
2523
2524 thaw_bdev(md->bdev, md->frozen_sb);
2525 md->frozen_sb = NULL;
2526 clear_bit(DMF_FROZEN, &md->flags);
2527}
2528
2529/*
2530 * We need to be able to change a mapping table under a mounted
2531 * filesystem. For example we might want to move some data in
2532 * the background. Before the table can be swapped with
2533 * dm_bind_table, dm_suspend must be called to flush any in
2534 * flight bios and ensure that any further io gets deferred.
2535 */
2536/*
2537 * Suspend mechanism in request-based dm.
2538 *
2539 * 1. Flush all I/Os by lock_fs() if needed.
2540 * 2. Stop dispatching any I/O by stopping the request_queue.
2541 * 3. Wait for all in-flight I/Os to be completed or requeued.
2542 *
2543 * To abort suspend, start the request_queue.
2544 */
2545int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
2546{
2547 struct dm_table *map = NULL;
2548 int r = 0;
2549 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
2550 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
2551
2552 mutex_lock(&md->suspend_lock);
2553
2554 if (dm_suspended_md(md)) {
2555 r = -EINVAL;
2556 goto out_unlock;
2557 }
2558
2559 map = md->map;
2560
2561 /*
2562 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2563 * This flag is cleared before dm_suspend returns.
2564 */
2565 if (noflush)
2566 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2567
2568 /* This does not get reverted if there's an error later. */
2569 dm_table_presuspend_targets(map);
2570
2571 /*
2572 * Flush I/O to the device.
2573 * Any I/O submitted after lock_fs() may not be flushed.
2574 * noflush takes precedence over do_lockfs.
2575 * (lock_fs() flushes I/Os and waits for them to complete.)
2576 */
2577 if (!noflush && do_lockfs) {
2578 r = lock_fs(md);
2579 if (r)
2580 goto out_unlock;
2581 }
2582
2583 /*
2584 * Here we must make sure that no processes are submitting requests
2585 * to target drivers i.e. no one may be executing
2586 * __split_and_process_bio. This is called from dm_request and
2587 * dm_wq_work.
2588 *
2589 * To get all processes out of __split_and_process_bio in dm_request,
2590 * we take the write lock. To prevent any process from reentering
2591 * __split_and_process_bio from dm_request and quiesce the thread
2592 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
2593 * flush_workqueue(md->wq).
2594 */
2595 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2596 synchronize_srcu(&md->io_barrier);
2597
2598 /*
2599 * Stop md->queue before flushing md->wq in case request-based
2600 * dm defers requests to md->wq from md->queue.
2601 */
2602 if (dm_request_based(md))
2603 stop_queue(md->queue);
2604
2605 flush_workqueue(md->wq);
2606
2607 /*
2608 * At this point no more requests are entering target request routines.
2609 * We call dm_wait_for_completion to wait for all existing requests
2610 * to finish.
2611 */
2612 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
2613
2614 if (noflush)
2615 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2616 synchronize_srcu(&md->io_barrier);
2617
2618 /* were we interrupted ? */
2619 if (r < 0) {
2620 dm_queue_flush(md);
2621
2622 if (dm_request_based(md))
2623 start_queue(md->queue);
2624
2625 unlock_fs(md);
2626 goto out_unlock; /* pushback list is already flushed, so skip flush */
2627 }
2628
2629 /*
2630 * If dm_wait_for_completion returned 0, the device is completely
2631 * quiescent now. There is no request-processing activity. All new
2632 * requests are being added to md->deferred list.
2633 */
2634
2635 set_bit(DMF_SUSPENDED, &md->flags);
2636
2637 dm_table_postsuspend_targets(map);
2638
2639out_unlock:
2640 mutex_unlock(&md->suspend_lock);
2641 return r;
2642}
2643
2644int dm_resume(struct mapped_device *md)
2645{
2646 int r = -EINVAL;
2647 struct dm_table *map = NULL;
2648
2649 mutex_lock(&md->suspend_lock);
2650 if (!dm_suspended_md(md))
2651 goto out;
2652
2653 map = md->map;
2654 if (!map || !dm_table_get_size(map))
2655 goto out;
2656
2657 r = dm_table_resume_targets(map);
2658 if (r)
2659 goto out;
2660
2661 dm_queue_flush(md);
2662
2663 /*
2664 * Flushing deferred I/Os must be done after targets are resumed
2665 * so that mapping of targets can work correctly.
2666 * Request-based dm is queueing the deferred I/Os in its request_queue.
2667 */
2668 if (dm_request_based(md))
2669 start_queue(md->queue);
2670
2671 unlock_fs(md);
2672
2673 clear_bit(DMF_SUSPENDED, &md->flags);
2674
2675 r = 0;
2676out:
2677 mutex_unlock(&md->suspend_lock);
2678
2679 return r;
2680}
2681
2682/*
2683 * Internal suspend/resume works like userspace-driven suspend. It waits
2684 * until all bios finish and prevents issuing new bios to the target drivers.
2685 * It may be used only from the kernel.
2686 *
2687 * Internal suspend holds md->suspend_lock, which prevents interaction with
2688 * userspace-driven suspend.
2689 */
2690
2691void dm_internal_suspend(struct mapped_device *md)
2692{
2693 mutex_lock(&md->suspend_lock);
2694 if (dm_suspended_md(md))
2695 return;
2696
2697 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2698 synchronize_srcu(&md->io_barrier);
2699 flush_workqueue(md->wq);
2700 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2701}
2702
2703void dm_internal_resume(struct mapped_device *md)
2704{
2705 if (dm_suspended_md(md))
2706 goto done;
2707
2708 dm_queue_flush(md);
2709
2710done:
2711 mutex_unlock(&md->suspend_lock);
2712}
2713
2714/*-----------------------------------------------------------------
2715 * Event notification.
2716 *---------------------------------------------------------------*/
2717int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
2718 unsigned cookie)
2719{
2720 char udev_cookie[DM_COOKIE_LENGTH];
2721 char *envp[] = { udev_cookie, NULL };
2722
2723 if (!cookie)
2724 return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
2725 else {
2726 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
2727 DM_COOKIE_ENV_VAR_NAME, cookie);
2728 return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
2729 action, envp);
2730 }
2731}
2732
2733uint32_t dm_next_uevent_seq(struct mapped_device *md)
2734{
2735 return atomic_add_return(1, &md->uevent_seq);
2736}
2737
2738uint32_t dm_get_event_nr(struct mapped_device *md)
2739{
2740 return atomic_read(&md->event_nr);
2741}
2742
2743int dm_wait_event(struct mapped_device *md, int event_nr)
2744{
2745 return wait_event_interruptible(md->eventq,
2746 (event_nr != atomic_read(&md->event_nr)));
2747}
2748
2749void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
2750{
2751 unsigned long flags;
2752
2753 spin_lock_irqsave(&md->uevent_lock, flags);
2754 list_add(elist, &md->uevent_list);
2755 spin_unlock_irqrestore(&md->uevent_lock, flags);
2756}
2757
2758/*
2759 * The gendisk is only valid as long as you have a reference
2760 * count on 'md'.
2761 */
2762struct gendisk *dm_disk(struct mapped_device *md)
2763{
2764 return md->disk;
2765}
2766
2767struct kobject *dm_kobject(struct mapped_device *md)
2768{
2769 return &md->kobj_holder.kobj;
2770}
2771
2772struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
2773{
2774 struct mapped_device *md;
2775
2776 md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
2777
2778 if (test_bit(DMF_FREEING, &md->flags) ||
2779 dm_deleting_md(md))
2780 return NULL;
2781
2782 dm_get(md);
2783 return md;
2784}
2785
2786int dm_suspended_md(struct mapped_device *md)
2787{
2788 return test_bit(DMF_SUSPENDED, &md->flags);
2789}
2790
2791int dm_test_deferred_remove_flag(struct mapped_device *md)
2792{
2793 return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
2794}
2795
2796int dm_suspended(struct dm_target *ti)
2797{
2798 return dm_suspended_md(dm_table_get_md(ti->table));
2799}
2800EXPORT_SYMBOL_GPL(dm_suspended);
2801
2802int dm_noflush_suspending(struct dm_target *ti)
2803{
2804 return __noflush_suspending(dm_table_get_md(ti->table));
2805}
2806EXPORT_SYMBOL_GPL(dm_noflush_suspending);
2807
2808struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size)
2809{
2810 struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
2811 struct kmem_cache *cachep;
2812 unsigned int pool_size;
2813 unsigned int front_pad;
2814
2815 if (!pools)
2816 return NULL;
2817
2818 if (type == DM_TYPE_BIO_BASED) {
2819 cachep = _io_cache;
2820 pool_size = dm_get_reserved_bio_based_ios();
2821 front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
2822 } else if (type == DM_TYPE_REQUEST_BASED) {
2823 cachep = _rq_tio_cache;
2824 pool_size = dm_get_reserved_rq_based_ios();
2825 front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
2826 /* per_bio_data_size is not used. See __bind_mempools(). */
2827 WARN_ON(per_bio_data_size != 0);
2828 } else
2829 goto out;
2830
2831 pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
2832 if (!pools->io_pool)
2833 goto out;
2834
2835 pools->bs = bioset_create(pool_size, front_pad);
2836 if (!pools->bs)
2837 goto out;
2838
2839 if (integrity && bioset_integrity_create(pools->bs, pool_size))
2840 goto out;
2841
2842 return pools;
2843
2844out:
2845 dm_free_md_mempools(pools);
2846
2847 return NULL;
2848}
2849
2850void dm_free_md_mempools(struct dm_md_mempools *pools)
2851{
2852 if (!pools)
2853 return;
2854
2855 if (pools->io_pool)
2856 mempool_destroy(pools->io_pool);
2857
2858 if (pools->bs)
2859 bioset_free(pools->bs);
2860
2861 kfree(pools);
2862}
2863
2864static const struct block_device_operations dm_blk_dops = {
2865 .open = dm_blk_open,
2866 .release = dm_blk_close,
2867 .ioctl = dm_blk_ioctl,
2868 .getgeo = dm_blk_getgeo,
2869 .owner = THIS_MODULE
2870};
2871
2872/*
2873 * module hooks
2874 */
2875module_init(dm_init);
2876module_exit(dm_exit);
2877
2878module_param(major, uint, 0);
2879MODULE_PARM_DESC(major, "The major number of the device mapper");
2880
2881module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
2882MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
2883
2884module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
2885MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
2886
2887MODULE_DESCRIPTION(DM_NAME " driver");
2888MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2889MODULE_LICENSE("GPL");