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/buffer_head.h>
18 #include <linux/mempool.h>
19 #include <linux/slab.h>
20 #include <linux/idr.h>
21 #include <linux/hdreg.h>
22
23 #include <trace/events/block.h>
24
25 #define DM_MSG_PREFIX "core"
26
27 /*
28 * Cookies are numeric values sent with CHANGE and REMOVE
29 * uevents while resuming, removing or renaming the device.
30 */
31 #define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
32 #define DM_COOKIE_LENGTH 24
33
34 static const char *_name = DM_NAME;
35
36 static unsigned int major = 0;
37 static unsigned int _major = 0;
38
39 static DEFINE_SPINLOCK(_minor_lock);
40 /*
41 * For bio-based dm.
42 * One of these is allocated per bio.
43 */
44 struct dm_io {
45 struct mapped_device *md;
46 int error;
47 atomic_t io_count;
48 struct bio *bio;
49 unsigned long start_time;
50 spinlock_t endio_lock;
51 };
52
53 /*
54 * For bio-based dm.
55 * One of these is allocated per target within a bio. Hopefully
56 * this will be simplified out one day.
57 */
58 struct dm_target_io {
59 struct dm_io *io;
60 struct dm_target *ti;
61 union map_info info;
62 };
63
64 /*
65 * For request-based dm.
66 * One of these is allocated per request.
67 */
68 struct dm_rq_target_io {
69 struct mapped_device *md;
70 struct dm_target *ti;
71 struct request *orig, clone;
72 int error;
73 union map_info info;
74 };
75
76 /*
77 * For request-based dm.
78 * One of these is allocated per bio.
79 */
80 struct dm_rq_clone_bio_info {
81 struct bio *orig;
82 struct dm_rq_target_io *tio;
83 };
84
85 union map_info *dm_get_mapinfo(struct bio *bio)
86 {
87 if (bio && bio->bi_private)
88 return &((struct dm_target_io *)bio->bi_private)->info;
89 return NULL;
90 }
91
92 union map_info *dm_get_rq_mapinfo(struct request *rq)
93 {
94 if (rq && rq->end_io_data)
95 return &((struct dm_rq_target_io *)rq->end_io_data)->info;
96 return NULL;
97 }
98 EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
99
100 #define MINOR_ALLOCED ((void *)-1)
101
102 /*
103 * Bits for the md->flags field.
104 */
105 #define DMF_BLOCK_IO_FOR_SUSPEND 0
106 #define DMF_SUSPENDED 1
107 #define DMF_FROZEN 2
108 #define DMF_FREEING 3
109 #define DMF_DELETING 4
110 #define DMF_NOFLUSH_SUSPENDING 5
111 #define DMF_QUEUE_IO_TO_THREAD 6
112
113 /*
114 * Work processed by per-device workqueue.
115 */
116 struct mapped_device {
117 struct rw_semaphore io_lock;
118 struct mutex suspend_lock;
119 rwlock_t map_lock;
120 atomic_t holders;
121 atomic_t open_count;
122
123 unsigned long flags;
124
125 struct request_queue *queue;
126 struct gendisk *disk;
127 char name[16];
128
129 void *interface_ptr;
130
131 /*
132 * A list of ios that arrived while we were suspended.
133 */
134 atomic_t pending;
135 wait_queue_head_t wait;
136 struct work_struct work;
137 struct bio_list deferred;
138 spinlock_t deferred_lock;
139
140 /*
141 * An error from the barrier request currently being processed.
142 */
143 int barrier_error;
144
145 /*
146 * Processing queue (flush/barriers)
147 */
148 struct workqueue_struct *wq;
149
150 /*
151 * The current mapping.
152 */
153 struct dm_table *map;
154
155 /*
156 * io objects are allocated from here.
157 */
158 mempool_t *io_pool;
159 mempool_t *tio_pool;
160
161 struct bio_set *bs;
162
163 /*
164 * Event handling.
165 */
166 atomic_t event_nr;
167 wait_queue_head_t eventq;
168 atomic_t uevent_seq;
169 struct list_head uevent_list;
170 spinlock_t uevent_lock; /* Protect access to uevent_list */
171
172 /*
173 * freeze/thaw support require holding onto a super block
174 */
175 struct super_block *frozen_sb;
176 struct block_device *bdev;
177
178 /* forced geometry settings */
179 struct hd_geometry geometry;
180
181 /* marker of flush suspend for request-based dm */
182 struct request suspend_rq;
183
184 /* For saving the address of __make_request for request based dm */
185 make_request_fn *saved_make_request_fn;
186
187 /* sysfs handle */
188 struct kobject kobj;
189
190 /* zero-length barrier that will be cloned and submitted to targets */
191 struct bio barrier_bio;
192 };
193
194 /*
195 * For mempools pre-allocation at the table loading time.
196 */
197 struct dm_md_mempools {
198 mempool_t *io_pool;
199 mempool_t *tio_pool;
200 struct bio_set *bs;
201 };
202
203 #define MIN_IOS 256
204 static struct kmem_cache *_io_cache;
205 static struct kmem_cache *_tio_cache;
206 static struct kmem_cache *_rq_tio_cache;
207 static struct kmem_cache *_rq_bio_info_cache;
208
209 static int __init local_init(void)
210 {
211 int r = -ENOMEM;
212
213 /* allocate a slab for the dm_ios */
214 _io_cache = KMEM_CACHE(dm_io, 0);
215 if (!_io_cache)
216 return r;
217
218 /* allocate a slab for the target ios */
219 _tio_cache = KMEM_CACHE(dm_target_io, 0);
220 if (!_tio_cache)
221 goto out_free_io_cache;
222
223 _rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
224 if (!_rq_tio_cache)
225 goto out_free_tio_cache;
226
227 _rq_bio_info_cache = KMEM_CACHE(dm_rq_clone_bio_info, 0);
228 if (!_rq_bio_info_cache)
229 goto out_free_rq_tio_cache;
230
231 r = dm_uevent_init();
232 if (r)
233 goto out_free_rq_bio_info_cache;
234
235 _major = major;
236 r = register_blkdev(_major, _name);
237 if (r < 0)
238 goto out_uevent_exit;
239
240 if (!_major)
241 _major = r;
242
243 return 0;
244
245 out_uevent_exit:
246 dm_uevent_exit();
247 out_free_rq_bio_info_cache:
248 kmem_cache_destroy(_rq_bio_info_cache);
249 out_free_rq_tio_cache:
250 kmem_cache_destroy(_rq_tio_cache);
251 out_free_tio_cache:
252 kmem_cache_destroy(_tio_cache);
253 out_free_io_cache:
254 kmem_cache_destroy(_io_cache);
255
256 return r;
257 }
258
259 static void local_exit(void)
260 {
261 kmem_cache_destroy(_rq_bio_info_cache);
262 kmem_cache_destroy(_rq_tio_cache);
263 kmem_cache_destroy(_tio_cache);
264 kmem_cache_destroy(_io_cache);
265 unregister_blkdev(_major, _name);
266 dm_uevent_exit();
267
268 _major = 0;
269
270 DMINFO("cleaned up");
271 }
272
273 static int (*_inits[])(void) __initdata = {
274 local_init,
275 dm_target_init,
276 dm_linear_init,
277 dm_stripe_init,
278 dm_kcopyd_init,
279 dm_interface_init,
280 };
281
282 static void (*_exits[])(void) = {
283 local_exit,
284 dm_target_exit,
285 dm_linear_exit,
286 dm_stripe_exit,
287 dm_kcopyd_exit,
288 dm_interface_exit,
289 };
290
291 static int __init dm_init(void)
292 {
293 const int count = ARRAY_SIZE(_inits);
294
295 int r, i;
296
297 for (i = 0; i < count; i++) {
298 r = _inits[i]();
299 if (r)
300 goto bad;
301 }
302
303 return 0;
304
305 bad:
306 while (i--)
307 _exits[i]();
308
309 return r;
310 }
311
312 static void __exit dm_exit(void)
313 {
314 int i = ARRAY_SIZE(_exits);
315
316 while (i--)
317 _exits[i]();
318 }
319
320 /*
321 * Block device functions
322 */
323 static int dm_blk_open(struct block_device *bdev, fmode_t mode)
324 {
325 struct mapped_device *md;
326
327 spin_lock(&_minor_lock);
328
329 md = bdev->bd_disk->private_data;
330 if (!md)
331 goto out;
332
333 if (test_bit(DMF_FREEING, &md->flags) ||
334 test_bit(DMF_DELETING, &md->flags)) {
335 md = NULL;
336 goto out;
337 }
338
339 dm_get(md);
340 atomic_inc(&md->open_count);
341
342 out:
343 spin_unlock(&_minor_lock);
344
345 return md ? 0 : -ENXIO;
346 }
347
348 static int dm_blk_close(struct gendisk *disk, fmode_t mode)
349 {
350 struct mapped_device *md = disk->private_data;
351 atomic_dec(&md->open_count);
352 dm_put(md);
353 return 0;
354 }
355
356 int 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 */
364 int dm_lock_for_deletion(struct mapped_device *md)
365 {
366 int r = 0;
367
368 spin_lock(&_minor_lock);
369
370 if (dm_open_count(md))
371 r = -EBUSY;
372 else
373 set_bit(DMF_DELETING, &md->flags);
374
375 spin_unlock(&_minor_lock);
376
377 return r;
378 }
379
380 static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
381 {
382 struct mapped_device *md = bdev->bd_disk->private_data;
383
384 return dm_get_geometry(md, geo);
385 }
386
387 static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
388 unsigned int cmd, unsigned long arg)
389 {
390 struct mapped_device *md = bdev->bd_disk->private_data;
391 struct dm_table *map = dm_get_table(md);
392 struct dm_target *tgt;
393 int r = -ENOTTY;
394
395 if (!map || !dm_table_get_size(map))
396 goto out;
397
398 /* We only support devices that have a single target */
399 if (dm_table_get_num_targets(map) != 1)
400 goto out;
401
402 tgt = dm_table_get_target(map, 0);
403
404 if (dm_suspended(md)) {
405 r = -EAGAIN;
406 goto out;
407 }
408
409 if (tgt->type->ioctl)
410 r = tgt->type->ioctl(tgt, cmd, arg);
411
412 out:
413 dm_table_put(map);
414
415 return r;
416 }
417
418 static struct dm_io *alloc_io(struct mapped_device *md)
419 {
420 return mempool_alloc(md->io_pool, GFP_NOIO);
421 }
422
423 static void free_io(struct mapped_device *md, struct dm_io *io)
424 {
425 mempool_free(io, md->io_pool);
426 }
427
428 static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
429 {
430 mempool_free(tio, md->tio_pool);
431 }
432
433 static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md)
434 {
435 return mempool_alloc(md->tio_pool, GFP_ATOMIC);
436 }
437
438 static void free_rq_tio(struct dm_rq_target_io *tio)
439 {
440 mempool_free(tio, tio->md->tio_pool);
441 }
442
443 static struct dm_rq_clone_bio_info *alloc_bio_info(struct mapped_device *md)
444 {
445 return mempool_alloc(md->io_pool, GFP_ATOMIC);
446 }
447
448 static void free_bio_info(struct dm_rq_clone_bio_info *info)
449 {
450 mempool_free(info, info->tio->md->io_pool);
451 }
452
453 static void start_io_acct(struct dm_io *io)
454 {
455 struct mapped_device *md = io->md;
456 int cpu;
457
458 io->start_time = jiffies;
459
460 cpu = part_stat_lock();
461 part_round_stats(cpu, &dm_disk(md)->part0);
462 part_stat_unlock();
463 dm_disk(md)->part0.in_flight = atomic_inc_return(&md->pending);
464 }
465
466 static void end_io_acct(struct dm_io *io)
467 {
468 struct mapped_device *md = io->md;
469 struct bio *bio = io->bio;
470 unsigned long duration = jiffies - io->start_time;
471 int pending, cpu;
472 int rw = bio_data_dir(bio);
473
474 cpu = part_stat_lock();
475 part_round_stats(cpu, &dm_disk(md)->part0);
476 part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
477 part_stat_unlock();
478
479 /*
480 * After this is decremented the bio must not be touched if it is
481 * a barrier.
482 */
483 dm_disk(md)->part0.in_flight = pending =
484 atomic_dec_return(&md->pending);
485
486 /* nudge anyone waiting on suspend queue */
487 if (!pending)
488 wake_up(&md->wait);
489 }
490
491 /*
492 * Add the bio to the list of deferred io.
493 */
494 static void queue_io(struct mapped_device *md, struct bio *bio)
495 {
496 down_write(&md->io_lock);
497
498 spin_lock_irq(&md->deferred_lock);
499 bio_list_add(&md->deferred, bio);
500 spin_unlock_irq(&md->deferred_lock);
501
502 if (!test_and_set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags))
503 queue_work(md->wq, &md->work);
504
505 up_write(&md->io_lock);
506 }
507
508 /*
509 * Everyone (including functions in this file), should use this
510 * function to access the md->map field, and make sure they call
511 * dm_table_put() when finished.
512 */
513 struct dm_table *dm_get_table(struct mapped_device *md)
514 {
515 struct dm_table *t;
516 unsigned long flags;
517
518 read_lock_irqsave(&md->map_lock, flags);
519 t = md->map;
520 if (t)
521 dm_table_get(t);
522 read_unlock_irqrestore(&md->map_lock, flags);
523
524 return t;
525 }
526
527 /*
528 * Get the geometry associated with a dm device
529 */
530 int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
531 {
532 *geo = md->geometry;
533
534 return 0;
535 }
536
537 /*
538 * Set the geometry of a device.
539 */
540 int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
541 {
542 sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
543
544 if (geo->start > sz) {
545 DMWARN("Start sector is beyond the geometry limits.");
546 return -EINVAL;
547 }
548
549 md->geometry = *geo;
550
551 return 0;
552 }
553
554 /*-----------------------------------------------------------------
555 * CRUD START:
556 * A more elegant soln is in the works that uses the queue
557 * merge fn, unfortunately there are a couple of changes to
558 * the block layer that I want to make for this. So in the
559 * interests of getting something for people to use I give
560 * you this clearly demarcated crap.
561 *---------------------------------------------------------------*/
562
563 static int __noflush_suspending(struct mapped_device *md)
564 {
565 return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
566 }
567
568 /*
569 * Decrements the number of outstanding ios that a bio has been
570 * cloned into, completing the original io if necc.
571 */
572 static void dec_pending(struct dm_io *io, int error)
573 {
574 unsigned long flags;
575 int io_error;
576 struct bio *bio;
577 struct mapped_device *md = io->md;
578
579 /* Push-back supersedes any I/O errors */
580 if (unlikely(error)) {
581 spin_lock_irqsave(&io->endio_lock, flags);
582 if (!(io->error > 0 && __noflush_suspending(md)))
583 io->error = error;
584 spin_unlock_irqrestore(&io->endio_lock, flags);
585 }
586
587 if (atomic_dec_and_test(&io->io_count)) {
588 if (io->error == DM_ENDIO_REQUEUE) {
589 /*
590 * Target requested pushing back the I/O.
591 */
592 spin_lock_irqsave(&md->deferred_lock, flags);
593 if (__noflush_suspending(md)) {
594 if (!bio_barrier(io->bio))
595 bio_list_add_head(&md->deferred,
596 io->bio);
597 } else
598 /* noflush suspend was interrupted. */
599 io->error = -EIO;
600 spin_unlock_irqrestore(&md->deferred_lock, flags);
601 }
602
603 io_error = io->error;
604 bio = io->bio;
605
606 if (bio_barrier(bio)) {
607 /*
608 * There can be just one barrier request so we use
609 * a per-device variable for error reporting.
610 * Note that you can't touch the bio after end_io_acct
611 */
612 if (!md->barrier_error && io_error != -EOPNOTSUPP)
613 md->barrier_error = io_error;
614 end_io_acct(io);
615 } else {
616 end_io_acct(io);
617
618 if (io_error != DM_ENDIO_REQUEUE) {
619 trace_block_bio_complete(md->queue, bio);
620
621 bio_endio(bio, io_error);
622 }
623 }
624
625 free_io(md, io);
626 }
627 }
628
629 static void clone_endio(struct bio *bio, int error)
630 {
631 int r = 0;
632 struct dm_target_io *tio = bio->bi_private;
633 struct dm_io *io = tio->io;
634 struct mapped_device *md = tio->io->md;
635 dm_endio_fn endio = tio->ti->type->end_io;
636
637 if (!bio_flagged(bio, BIO_UPTODATE) && !error)
638 error = -EIO;
639
640 if (endio) {
641 r = endio(tio->ti, bio, error, &tio->info);
642 if (r < 0 || r == DM_ENDIO_REQUEUE)
643 /*
644 * error and requeue request are handled
645 * in dec_pending().
646 */
647 error = r;
648 else if (r == DM_ENDIO_INCOMPLETE)
649 /* The target will handle the io */
650 return;
651 else if (r) {
652 DMWARN("unimplemented target endio return value: %d", r);
653 BUG();
654 }
655 }
656
657 /*
658 * Store md for cleanup instead of tio which is about to get freed.
659 */
660 bio->bi_private = md->bs;
661
662 free_tio(md, tio);
663 bio_put(bio);
664 dec_pending(io, error);
665 }
666
667 /*
668 * Partial completion handling for request-based dm
669 */
670 static void end_clone_bio(struct bio *clone, int error)
671 {
672 struct dm_rq_clone_bio_info *info = clone->bi_private;
673 struct dm_rq_target_io *tio = info->tio;
674 struct bio *bio = info->orig;
675 unsigned int nr_bytes = info->orig->bi_size;
676
677 bio_put(clone);
678
679 if (tio->error)
680 /*
681 * An error has already been detected on the request.
682 * Once error occurred, just let clone->end_io() handle
683 * the remainder.
684 */
685 return;
686 else if (error) {
687 /*
688 * Don't notice the error to the upper layer yet.
689 * The error handling decision is made by the target driver,
690 * when the request is completed.
691 */
692 tio->error = error;
693 return;
694 }
695
696 /*
697 * I/O for the bio successfully completed.
698 * Notice the data completion to the upper layer.
699 */
700
701 /*
702 * bios are processed from the head of the list.
703 * So the completing bio should always be rq->bio.
704 * If it's not, something wrong is happening.
705 */
706 if (tio->orig->bio != bio)
707 DMERR("bio completion is going in the middle of the request");
708
709 /*
710 * Update the original request.
711 * Do not use blk_end_request() here, because it may complete
712 * the original request before the clone, and break the ordering.
713 */
714 blk_update_request(tio->orig, 0, nr_bytes);
715 }
716
717 /*
718 * Don't touch any member of the md after calling this function because
719 * the md may be freed in dm_put() at the end of this function.
720 * Or do dm_get() before calling this function and dm_put() later.
721 */
722 static void rq_completed(struct mapped_device *md, int run_queue)
723 {
724 int wakeup_waiters = 0;
725 struct request_queue *q = md->queue;
726 unsigned long flags;
727
728 spin_lock_irqsave(q->queue_lock, flags);
729 if (!queue_in_flight(q))
730 wakeup_waiters = 1;
731 spin_unlock_irqrestore(q->queue_lock, flags);
732
733 /* nudge anyone waiting on suspend queue */
734 if (wakeup_waiters)
735 wake_up(&md->wait);
736
737 if (run_queue)
738 blk_run_queue(q);
739
740 /*
741 * dm_put() must be at the end of this function. See the comment above
742 */
743 dm_put(md);
744 }
745
746 static void free_rq_clone(struct request *clone)
747 {
748 struct dm_rq_target_io *tio = clone->end_io_data;
749
750 blk_rq_unprep_clone(clone);
751 free_rq_tio(tio);
752 }
753
754 static void dm_unprep_request(struct request *rq)
755 {
756 struct request *clone = rq->special;
757
758 rq->special = NULL;
759 rq->cmd_flags &= ~REQ_DONTPREP;
760
761 free_rq_clone(clone);
762 }
763
764 /*
765 * Requeue the original request of a clone.
766 */
767 void dm_requeue_unmapped_request(struct request *clone)
768 {
769 struct dm_rq_target_io *tio = clone->end_io_data;
770 struct mapped_device *md = tio->md;
771 struct request *rq = tio->orig;
772 struct request_queue *q = rq->q;
773 unsigned long flags;
774
775 dm_unprep_request(rq);
776
777 spin_lock_irqsave(q->queue_lock, flags);
778 if (elv_queue_empty(q))
779 blk_plug_device(q);
780 blk_requeue_request(q, rq);
781 spin_unlock_irqrestore(q->queue_lock, flags);
782
783 rq_completed(md, 0);
784 }
785 EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
786
787 static void __stop_queue(struct request_queue *q)
788 {
789 blk_stop_queue(q);
790 }
791
792 static void stop_queue(struct request_queue *q)
793 {
794 unsigned long flags;
795
796 spin_lock_irqsave(q->queue_lock, flags);
797 __stop_queue(q);
798 spin_unlock_irqrestore(q->queue_lock, flags);
799 }
800
801 static void __start_queue(struct request_queue *q)
802 {
803 if (blk_queue_stopped(q))
804 blk_start_queue(q);
805 }
806
807 static void start_queue(struct request_queue *q)
808 {
809 unsigned long flags;
810
811 spin_lock_irqsave(q->queue_lock, flags);
812 __start_queue(q);
813 spin_unlock_irqrestore(q->queue_lock, flags);
814 }
815
816 /*
817 * Complete the clone and the original request.
818 * Must be called without queue lock.
819 */
820 static void dm_end_request(struct request *clone, int error)
821 {
822 struct dm_rq_target_io *tio = clone->end_io_data;
823 struct mapped_device *md = tio->md;
824 struct request *rq = tio->orig;
825
826 if (blk_pc_request(rq)) {
827 rq->errors = clone->errors;
828 rq->resid_len = clone->resid_len;
829
830 if (rq->sense)
831 /*
832 * We are using the sense buffer of the original
833 * request.
834 * So setting the length of the sense data is enough.
835 */
836 rq->sense_len = clone->sense_len;
837 }
838
839 free_rq_clone(clone);
840
841 blk_end_request_all(rq, error);
842
843 rq_completed(md, 1);
844 }
845
846 /*
847 * Request completion handler for request-based dm
848 */
849 static void dm_softirq_done(struct request *rq)
850 {
851 struct request *clone = rq->completion_data;
852 struct dm_rq_target_io *tio = clone->end_io_data;
853 dm_request_endio_fn rq_end_io = tio->ti->type->rq_end_io;
854 int error = tio->error;
855
856 if (!(rq->cmd_flags & REQ_FAILED) && rq_end_io)
857 error = rq_end_io(tio->ti, clone, error, &tio->info);
858
859 if (error <= 0)
860 /* The target wants to complete the I/O */
861 dm_end_request(clone, error);
862 else if (error == DM_ENDIO_INCOMPLETE)
863 /* The target will handle the I/O */
864 return;
865 else if (error == DM_ENDIO_REQUEUE)
866 /* The target wants to requeue the I/O */
867 dm_requeue_unmapped_request(clone);
868 else {
869 DMWARN("unimplemented target endio return value: %d", error);
870 BUG();
871 }
872 }
873
874 /*
875 * Complete the clone and the original request with the error status
876 * through softirq context.
877 */
878 static void dm_complete_request(struct request *clone, int error)
879 {
880 struct dm_rq_target_io *tio = clone->end_io_data;
881 struct request *rq = tio->orig;
882
883 tio->error = error;
884 rq->completion_data = clone;
885 blk_complete_request(rq);
886 }
887
888 /*
889 * Complete the not-mapped clone and the original request with the error status
890 * through softirq context.
891 * Target's rq_end_io() function isn't called.
892 * This may be used when the target's map_rq() function fails.
893 */
894 void dm_kill_unmapped_request(struct request *clone, int error)
895 {
896 struct dm_rq_target_io *tio = clone->end_io_data;
897 struct request *rq = tio->orig;
898
899 rq->cmd_flags |= REQ_FAILED;
900 dm_complete_request(clone, error);
901 }
902 EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
903
904 /*
905 * Called with the queue lock held
906 */
907 static void end_clone_request(struct request *clone, int error)
908 {
909 /*
910 * For just cleaning up the information of the queue in which
911 * the clone was dispatched.
912 * The clone is *NOT* freed actually here because it is alloced from
913 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
914 */
915 __blk_put_request(clone->q, clone);
916
917 /*
918 * Actual request completion is done in a softirq context which doesn't
919 * hold the queue lock. Otherwise, deadlock could occur because:
920 * - another request may be submitted by the upper level driver
921 * of the stacking during the completion
922 * - the submission which requires queue lock may be done
923 * against this queue
924 */
925 dm_complete_request(clone, error);
926 }
927
928 static sector_t max_io_len(struct mapped_device *md,
929 sector_t sector, struct dm_target *ti)
930 {
931 sector_t offset = sector - ti->begin;
932 sector_t len = ti->len - offset;
933
934 /*
935 * Does the target need to split even further ?
936 */
937 if (ti->split_io) {
938 sector_t boundary;
939 boundary = ((offset + ti->split_io) & ~(ti->split_io - 1))
940 - offset;
941 if (len > boundary)
942 len = boundary;
943 }
944
945 return len;
946 }
947
948 static void __map_bio(struct dm_target *ti, struct bio *clone,
949 struct dm_target_io *tio)
950 {
951 int r;
952 sector_t sector;
953 struct mapped_device *md;
954
955 clone->bi_end_io = clone_endio;
956 clone->bi_private = tio;
957
958 /*
959 * Map the clone. If r == 0 we don't need to do
960 * anything, the target has assumed ownership of
961 * this io.
962 */
963 atomic_inc(&tio->io->io_count);
964 sector = clone->bi_sector;
965 r = ti->type->map(ti, clone, &tio->info);
966 if (r == DM_MAPIO_REMAPPED) {
967 /* the bio has been remapped so dispatch it */
968
969 trace_block_remap(bdev_get_queue(clone->bi_bdev), clone,
970 tio->io->bio->bi_bdev->bd_dev, sector);
971
972 generic_make_request(clone);
973 } else if (r < 0 || r == DM_MAPIO_REQUEUE) {
974 /* error the io and bail out, or requeue it if needed */
975 md = tio->io->md;
976 dec_pending(tio->io, r);
977 /*
978 * Store bio_set for cleanup.
979 */
980 clone->bi_private = md->bs;
981 bio_put(clone);
982 free_tio(md, tio);
983 } else if (r) {
984 DMWARN("unimplemented target map return value: %d", r);
985 BUG();
986 }
987 }
988
989 struct clone_info {
990 struct mapped_device *md;
991 struct dm_table *map;
992 struct bio *bio;
993 struct dm_io *io;
994 sector_t sector;
995 sector_t sector_count;
996 unsigned short idx;
997 };
998
999 static void dm_bio_destructor(struct bio *bio)
1000 {
1001 struct bio_set *bs = bio->bi_private;
1002
1003 bio_free(bio, bs);
1004 }
1005
1006 /*
1007 * Creates a little bio that is just does part of a bvec.
1008 */
1009 static struct bio *split_bvec(struct bio *bio, sector_t sector,
1010 unsigned short idx, unsigned int offset,
1011 unsigned int len, struct bio_set *bs)
1012 {
1013 struct bio *clone;
1014 struct bio_vec *bv = bio->bi_io_vec + idx;
1015
1016 clone = bio_alloc_bioset(GFP_NOIO, 1, bs);
1017 clone->bi_destructor = dm_bio_destructor;
1018 *clone->bi_io_vec = *bv;
1019
1020 clone->bi_sector = sector;
1021 clone->bi_bdev = bio->bi_bdev;
1022 clone->bi_rw = bio->bi_rw & ~(1 << BIO_RW_BARRIER);
1023 clone->bi_vcnt = 1;
1024 clone->bi_size = to_bytes(len);
1025 clone->bi_io_vec->bv_offset = offset;
1026 clone->bi_io_vec->bv_len = clone->bi_size;
1027 clone->bi_flags |= 1 << BIO_CLONED;
1028
1029 if (bio_integrity(bio)) {
1030 bio_integrity_clone(clone, bio, GFP_NOIO, bs);
1031 bio_integrity_trim(clone,
1032 bio_sector_offset(bio, idx, offset), len);
1033 }
1034
1035 return clone;
1036 }
1037
1038 /*
1039 * Creates a bio that consists of range of complete bvecs.
1040 */
1041 static struct bio *clone_bio(struct bio *bio, sector_t sector,
1042 unsigned short idx, unsigned short bv_count,
1043 unsigned int len, struct bio_set *bs)
1044 {
1045 struct bio *clone;
1046
1047 clone = bio_alloc_bioset(GFP_NOIO, bio->bi_max_vecs, bs);
1048 __bio_clone(clone, bio);
1049 clone->bi_rw &= ~(1 << BIO_RW_BARRIER);
1050 clone->bi_destructor = dm_bio_destructor;
1051 clone->bi_sector = sector;
1052 clone->bi_idx = idx;
1053 clone->bi_vcnt = idx + bv_count;
1054 clone->bi_size = to_bytes(len);
1055 clone->bi_flags &= ~(1 << BIO_SEG_VALID);
1056
1057 if (bio_integrity(bio)) {
1058 bio_integrity_clone(clone, bio, GFP_NOIO, bs);
1059
1060 if (idx != bio->bi_idx || clone->bi_size < bio->bi_size)
1061 bio_integrity_trim(clone,
1062 bio_sector_offset(bio, idx, 0), len);
1063 }
1064
1065 return clone;
1066 }
1067
1068 static struct dm_target_io *alloc_tio(struct clone_info *ci,
1069 struct dm_target *ti)
1070 {
1071 struct dm_target_io *tio = mempool_alloc(ci->md->tio_pool, GFP_NOIO);
1072
1073 tio->io = ci->io;
1074 tio->ti = ti;
1075 memset(&tio->info, 0, sizeof(tio->info));
1076
1077 return tio;
1078 }
1079
1080 static void __flush_target(struct clone_info *ci, struct dm_target *ti,
1081 unsigned flush_nr)
1082 {
1083 struct dm_target_io *tio = alloc_tio(ci, ti);
1084 struct bio *clone;
1085
1086 tio->info.flush_request = flush_nr;
1087
1088 clone = bio_alloc_bioset(GFP_NOIO, 0, ci->md->bs);
1089 __bio_clone(clone, ci->bio);
1090 clone->bi_destructor = dm_bio_destructor;
1091
1092 __map_bio(ti, clone, tio);
1093 }
1094
1095 static int __clone_and_map_empty_barrier(struct clone_info *ci)
1096 {
1097 unsigned target_nr = 0, flush_nr;
1098 struct dm_target *ti;
1099
1100 while ((ti = dm_table_get_target(ci->map, target_nr++)))
1101 for (flush_nr = 0; flush_nr < ti->num_flush_requests;
1102 flush_nr++)
1103 __flush_target(ci, ti, flush_nr);
1104
1105 ci->sector_count = 0;
1106
1107 return 0;
1108 }
1109
1110 static int __clone_and_map(struct clone_info *ci)
1111 {
1112 struct bio *clone, *bio = ci->bio;
1113 struct dm_target *ti;
1114 sector_t len = 0, max;
1115 struct dm_target_io *tio;
1116
1117 if (unlikely(bio_empty_barrier(bio)))
1118 return __clone_and_map_empty_barrier(ci);
1119
1120 ti = dm_table_find_target(ci->map, ci->sector);
1121 if (!dm_target_is_valid(ti))
1122 return -EIO;
1123
1124 max = max_io_len(ci->md, ci->sector, ti);
1125
1126 /*
1127 * Allocate a target io object.
1128 */
1129 tio = alloc_tio(ci, ti);
1130
1131 if (ci->sector_count <= max) {
1132 /*
1133 * Optimise for the simple case where we can do all of
1134 * the remaining io with a single clone.
1135 */
1136 clone = clone_bio(bio, ci->sector, ci->idx,
1137 bio->bi_vcnt - ci->idx, ci->sector_count,
1138 ci->md->bs);
1139 __map_bio(ti, clone, tio);
1140 ci->sector_count = 0;
1141
1142 } else if (to_sector(bio->bi_io_vec[ci->idx].bv_len) <= max) {
1143 /*
1144 * There are some bvecs that don't span targets.
1145 * Do as many of these as possible.
1146 */
1147 int i;
1148 sector_t remaining = max;
1149 sector_t bv_len;
1150
1151 for (i = ci->idx; remaining && (i < bio->bi_vcnt); i++) {
1152 bv_len = to_sector(bio->bi_io_vec[i].bv_len);
1153
1154 if (bv_len > remaining)
1155 break;
1156
1157 remaining -= bv_len;
1158 len += bv_len;
1159 }
1160
1161 clone = clone_bio(bio, ci->sector, ci->idx, i - ci->idx, len,
1162 ci->md->bs);
1163 __map_bio(ti, clone, tio);
1164
1165 ci->sector += len;
1166 ci->sector_count -= len;
1167 ci->idx = i;
1168
1169 } else {
1170 /*
1171 * Handle a bvec that must be split between two or more targets.
1172 */
1173 struct bio_vec *bv = bio->bi_io_vec + ci->idx;
1174 sector_t remaining = to_sector(bv->bv_len);
1175 unsigned int offset = 0;
1176
1177 do {
1178 if (offset) {
1179 ti = dm_table_find_target(ci->map, ci->sector);
1180 if (!dm_target_is_valid(ti))
1181 return -EIO;
1182
1183 max = max_io_len(ci->md, ci->sector, ti);
1184
1185 tio = alloc_tio(ci, ti);
1186 }
1187
1188 len = min(remaining, max);
1189
1190 clone = split_bvec(bio, ci->sector, ci->idx,
1191 bv->bv_offset + offset, len,
1192 ci->md->bs);
1193
1194 __map_bio(ti, clone, tio);
1195
1196 ci->sector += len;
1197 ci->sector_count -= len;
1198 offset += to_bytes(len);
1199 } while (remaining -= len);
1200
1201 ci->idx++;
1202 }
1203
1204 return 0;
1205 }
1206
1207 /*
1208 * Split the bio into several clones and submit it to targets.
1209 */
1210 static void __split_and_process_bio(struct mapped_device *md, struct bio *bio)
1211 {
1212 struct clone_info ci;
1213 int error = 0;
1214
1215 ci.map = dm_get_table(md);
1216 if (unlikely(!ci.map)) {
1217 if (!bio_barrier(bio))
1218 bio_io_error(bio);
1219 else
1220 if (!md->barrier_error)
1221 md->barrier_error = -EIO;
1222 return;
1223 }
1224
1225 ci.md = md;
1226 ci.bio = bio;
1227 ci.io = alloc_io(md);
1228 ci.io->error = 0;
1229 atomic_set(&ci.io->io_count, 1);
1230 ci.io->bio = bio;
1231 ci.io->md = md;
1232 spin_lock_init(&ci.io->endio_lock);
1233 ci.sector = bio->bi_sector;
1234 ci.sector_count = bio_sectors(bio);
1235 if (unlikely(bio_empty_barrier(bio)))
1236 ci.sector_count = 1;
1237 ci.idx = bio->bi_idx;
1238
1239 start_io_acct(ci.io);
1240 while (ci.sector_count && !error)
1241 error = __clone_and_map(&ci);
1242
1243 /* drop the extra reference count */
1244 dec_pending(ci.io, error);
1245 dm_table_put(ci.map);
1246 }
1247 /*-----------------------------------------------------------------
1248 * CRUD END
1249 *---------------------------------------------------------------*/
1250
1251 static int dm_merge_bvec(struct request_queue *q,
1252 struct bvec_merge_data *bvm,
1253 struct bio_vec *biovec)
1254 {
1255 struct mapped_device *md = q->queuedata;
1256 struct dm_table *map = dm_get_table(md);
1257 struct dm_target *ti;
1258 sector_t max_sectors;
1259 int max_size = 0;
1260
1261 if (unlikely(!map))
1262 goto out;
1263
1264 ti = dm_table_find_target(map, bvm->bi_sector);
1265 if (!dm_target_is_valid(ti))
1266 goto out_table;
1267
1268 /*
1269 * Find maximum amount of I/O that won't need splitting
1270 */
1271 max_sectors = min(max_io_len(md, bvm->bi_sector, ti),
1272 (sector_t) BIO_MAX_SECTORS);
1273 max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
1274 if (max_size < 0)
1275 max_size = 0;
1276
1277 /*
1278 * merge_bvec_fn() returns number of bytes
1279 * it can accept at this offset
1280 * max is precomputed maximal io size
1281 */
1282 if (max_size && ti->type->merge)
1283 max_size = ti->type->merge(ti, bvm, biovec, max_size);
1284 /*
1285 * If the target doesn't support merge method and some of the devices
1286 * provided their merge_bvec method (we know this by looking at
1287 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1288 * entries. So always set max_size to 0, and the code below allows
1289 * just one page.
1290 */
1291 else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
1292
1293 max_size = 0;
1294
1295 out_table:
1296 dm_table_put(map);
1297
1298 out:
1299 /*
1300 * Always allow an entire first page
1301 */
1302 if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
1303 max_size = biovec->bv_len;
1304
1305 return max_size;
1306 }
1307
1308 /*
1309 * The request function that just remaps the bio built up by
1310 * dm_merge_bvec.
1311 */
1312 static int _dm_request(struct request_queue *q, struct bio *bio)
1313 {
1314 int rw = bio_data_dir(bio);
1315 struct mapped_device *md = q->queuedata;
1316 int cpu;
1317
1318 down_read(&md->io_lock);
1319
1320 cpu = part_stat_lock();
1321 part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
1322 part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
1323 part_stat_unlock();
1324
1325 /*
1326 * If we're suspended or the thread is processing barriers
1327 * we have to queue this io for later.
1328 */
1329 if (unlikely(test_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags)) ||
1330 unlikely(bio_barrier(bio))) {
1331 up_read(&md->io_lock);
1332
1333 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) &&
1334 bio_rw(bio) == READA) {
1335 bio_io_error(bio);
1336 return 0;
1337 }
1338
1339 queue_io(md, bio);
1340
1341 return 0;
1342 }
1343
1344 __split_and_process_bio(md, bio);
1345 up_read(&md->io_lock);
1346 return 0;
1347 }
1348
1349 static int dm_make_request(struct request_queue *q, struct bio *bio)
1350 {
1351 struct mapped_device *md = q->queuedata;
1352
1353 if (unlikely(bio_barrier(bio))) {
1354 bio_endio(bio, -EOPNOTSUPP);
1355 return 0;
1356 }
1357
1358 return md->saved_make_request_fn(q, bio); /* call __make_request() */
1359 }
1360
1361 static int dm_request_based(struct mapped_device *md)
1362 {
1363 return blk_queue_stackable(md->queue);
1364 }
1365
1366 static int dm_request(struct request_queue *q, struct bio *bio)
1367 {
1368 struct mapped_device *md = q->queuedata;
1369
1370 if (dm_request_based(md))
1371 return dm_make_request(q, bio);
1372
1373 return _dm_request(q, bio);
1374 }
1375
1376 void dm_dispatch_request(struct request *rq)
1377 {
1378 int r;
1379
1380 if (blk_queue_io_stat(rq->q))
1381 rq->cmd_flags |= REQ_IO_STAT;
1382
1383 rq->start_time = jiffies;
1384 r = blk_insert_cloned_request(rq->q, rq);
1385 if (r)
1386 dm_complete_request(rq, r);
1387 }
1388 EXPORT_SYMBOL_GPL(dm_dispatch_request);
1389
1390 static void dm_rq_bio_destructor(struct bio *bio)
1391 {
1392 struct dm_rq_clone_bio_info *info = bio->bi_private;
1393 struct mapped_device *md = info->tio->md;
1394
1395 free_bio_info(info);
1396 bio_free(bio, md->bs);
1397 }
1398
1399 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
1400 void *data)
1401 {
1402 struct dm_rq_target_io *tio = data;
1403 struct mapped_device *md = tio->md;
1404 struct dm_rq_clone_bio_info *info = alloc_bio_info(md);
1405
1406 if (!info)
1407 return -ENOMEM;
1408
1409 info->orig = bio_orig;
1410 info->tio = tio;
1411 bio->bi_end_io = end_clone_bio;
1412 bio->bi_private = info;
1413 bio->bi_destructor = dm_rq_bio_destructor;
1414
1415 return 0;
1416 }
1417
1418 static int setup_clone(struct request *clone, struct request *rq,
1419 struct dm_rq_target_io *tio)
1420 {
1421 int r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
1422 dm_rq_bio_constructor, tio);
1423
1424 if (r)
1425 return r;
1426
1427 clone->cmd = rq->cmd;
1428 clone->cmd_len = rq->cmd_len;
1429 clone->sense = rq->sense;
1430 clone->buffer = rq->buffer;
1431 clone->end_io = end_clone_request;
1432 clone->end_io_data = tio;
1433
1434 return 0;
1435 }
1436
1437 static int dm_rq_flush_suspending(struct mapped_device *md)
1438 {
1439 return !md->suspend_rq.special;
1440 }
1441
1442 /*
1443 * Called with the queue lock held.
1444 */
1445 static int dm_prep_fn(struct request_queue *q, struct request *rq)
1446 {
1447 struct mapped_device *md = q->queuedata;
1448 struct dm_rq_target_io *tio;
1449 struct request *clone;
1450
1451 if (unlikely(rq == &md->suspend_rq)) {
1452 if (dm_rq_flush_suspending(md))
1453 return BLKPREP_OK;
1454 else
1455 /* The flush suspend was interrupted */
1456 return BLKPREP_KILL;
1457 }
1458
1459 if (unlikely(rq->special)) {
1460 DMWARN("Already has something in rq->special.");
1461 return BLKPREP_KILL;
1462 }
1463
1464 tio = alloc_rq_tio(md); /* Only one for each original request */
1465 if (!tio)
1466 /* -ENOMEM */
1467 return BLKPREP_DEFER;
1468
1469 tio->md = md;
1470 tio->ti = NULL;
1471 tio->orig = rq;
1472 tio->error = 0;
1473 memset(&tio->info, 0, sizeof(tio->info));
1474
1475 clone = &tio->clone;
1476 if (setup_clone(clone, rq, tio)) {
1477 /* -ENOMEM */
1478 free_rq_tio(tio);
1479 return BLKPREP_DEFER;
1480 }
1481
1482 rq->special = clone;
1483 rq->cmd_flags |= REQ_DONTPREP;
1484
1485 return BLKPREP_OK;
1486 }
1487
1488 static void map_request(struct dm_target *ti, struct request *rq,
1489 struct mapped_device *md)
1490 {
1491 int r;
1492 struct request *clone = rq->special;
1493 struct dm_rq_target_io *tio = clone->end_io_data;
1494
1495 /*
1496 * Hold the md reference here for the in-flight I/O.
1497 * We can't rely on the reference count by device opener,
1498 * because the device may be closed during the request completion
1499 * when all bios are completed.
1500 * See the comment in rq_completed() too.
1501 */
1502 dm_get(md);
1503
1504 tio->ti = ti;
1505 r = ti->type->map_rq(ti, clone, &tio->info);
1506 switch (r) {
1507 case DM_MAPIO_SUBMITTED:
1508 /* The target has taken the I/O to submit by itself later */
1509 break;
1510 case DM_MAPIO_REMAPPED:
1511 /* The target has remapped the I/O so dispatch it */
1512 dm_dispatch_request(clone);
1513 break;
1514 case DM_MAPIO_REQUEUE:
1515 /* The target wants to requeue the I/O */
1516 dm_requeue_unmapped_request(clone);
1517 break;
1518 default:
1519 if (r > 0) {
1520 DMWARN("unimplemented target map return value: %d", r);
1521 BUG();
1522 }
1523
1524 /* The target wants to complete the I/O */
1525 dm_kill_unmapped_request(clone, r);
1526 break;
1527 }
1528 }
1529
1530 /*
1531 * q->request_fn for request-based dm.
1532 * Called with the queue lock held.
1533 */
1534 static void dm_request_fn(struct request_queue *q)
1535 {
1536 struct mapped_device *md = q->queuedata;
1537 struct dm_table *map = dm_get_table(md);
1538 struct dm_target *ti;
1539 struct request *rq;
1540
1541 /*
1542 * For noflush suspend, check blk_queue_stopped() to immediately
1543 * quit I/O dispatching.
1544 */
1545 while (!blk_queue_plugged(q) && !blk_queue_stopped(q)) {
1546 rq = blk_peek_request(q);
1547 if (!rq)
1548 goto plug_and_out;
1549
1550 if (unlikely(rq == &md->suspend_rq)) { /* Flush suspend maker */
1551 if (queue_in_flight(q))
1552 /* Not quiet yet. Wait more */
1553 goto plug_and_out;
1554
1555 /* This device should be quiet now */
1556 __stop_queue(q);
1557 blk_start_request(rq);
1558 __blk_end_request_all(rq, 0);
1559 wake_up(&md->wait);
1560 goto out;
1561 }
1562
1563 ti = dm_table_find_target(map, blk_rq_pos(rq));
1564 if (ti->type->busy && ti->type->busy(ti))
1565 goto plug_and_out;
1566
1567 blk_start_request(rq);
1568 spin_unlock(q->queue_lock);
1569 map_request(ti, rq, md);
1570 spin_lock_irq(q->queue_lock);
1571 }
1572
1573 goto out;
1574
1575 plug_and_out:
1576 if (!elv_queue_empty(q))
1577 /* Some requests still remain, retry later */
1578 blk_plug_device(q);
1579
1580 out:
1581 dm_table_put(map);
1582
1583 return;
1584 }
1585
1586 int dm_underlying_device_busy(struct request_queue *q)
1587 {
1588 return blk_lld_busy(q);
1589 }
1590 EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
1591
1592 static int dm_lld_busy(struct request_queue *q)
1593 {
1594 int r;
1595 struct mapped_device *md = q->queuedata;
1596 struct dm_table *map = dm_get_table(md);
1597
1598 if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
1599 r = 1;
1600 else
1601 r = dm_table_any_busy_target(map);
1602
1603 dm_table_put(map);
1604
1605 return r;
1606 }
1607
1608 static void dm_unplug_all(struct request_queue *q)
1609 {
1610 struct mapped_device *md = q->queuedata;
1611 struct dm_table *map = dm_get_table(md);
1612
1613 if (map) {
1614 if (dm_request_based(md))
1615 generic_unplug_device(q);
1616
1617 dm_table_unplug_all(map);
1618 dm_table_put(map);
1619 }
1620 }
1621
1622 static int dm_any_congested(void *congested_data, int bdi_bits)
1623 {
1624 int r = bdi_bits;
1625 struct mapped_device *md = congested_data;
1626 struct dm_table *map;
1627
1628 if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
1629 map = dm_get_table(md);
1630 if (map) {
1631 /*
1632 * Request-based dm cares about only own queue for
1633 * the query about congestion status of request_queue
1634 */
1635 if (dm_request_based(md))
1636 r = md->queue->backing_dev_info.state &
1637 bdi_bits;
1638 else
1639 r = dm_table_any_congested(map, bdi_bits);
1640
1641 dm_table_put(map);
1642 }
1643 }
1644
1645 return r;
1646 }
1647
1648 /*-----------------------------------------------------------------
1649 * An IDR is used to keep track of allocated minor numbers.
1650 *---------------------------------------------------------------*/
1651 static DEFINE_IDR(_minor_idr);
1652
1653 static void free_minor(int minor)
1654 {
1655 spin_lock(&_minor_lock);
1656 idr_remove(&_minor_idr, minor);
1657 spin_unlock(&_minor_lock);
1658 }
1659
1660 /*
1661 * See if the device with a specific minor # is free.
1662 */
1663 static int specific_minor(int minor)
1664 {
1665 int r, m;
1666
1667 if (minor >= (1 << MINORBITS))
1668 return -EINVAL;
1669
1670 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1671 if (!r)
1672 return -ENOMEM;
1673
1674 spin_lock(&_minor_lock);
1675
1676 if (idr_find(&_minor_idr, minor)) {
1677 r = -EBUSY;
1678 goto out;
1679 }
1680
1681 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
1682 if (r)
1683 goto out;
1684
1685 if (m != minor) {
1686 idr_remove(&_minor_idr, m);
1687 r = -EBUSY;
1688 goto out;
1689 }
1690
1691 out:
1692 spin_unlock(&_minor_lock);
1693 return r;
1694 }
1695
1696 static int next_free_minor(int *minor)
1697 {
1698 int r, m;
1699
1700 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
1701 if (!r)
1702 return -ENOMEM;
1703
1704 spin_lock(&_minor_lock);
1705
1706 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
1707 if (r)
1708 goto out;
1709
1710 if (m >= (1 << MINORBITS)) {
1711 idr_remove(&_minor_idr, m);
1712 r = -ENOSPC;
1713 goto out;
1714 }
1715
1716 *minor = m;
1717
1718 out:
1719 spin_unlock(&_minor_lock);
1720 return r;
1721 }
1722
1723 static struct block_device_operations dm_blk_dops;
1724
1725 static void dm_wq_work(struct work_struct *work);
1726
1727 /*
1728 * Allocate and initialise a blank device with a given minor.
1729 */
1730 static struct mapped_device *alloc_dev(int minor)
1731 {
1732 int r;
1733 struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1734 void *old_md;
1735
1736 if (!md) {
1737 DMWARN("unable to allocate device, out of memory.");
1738 return NULL;
1739 }
1740
1741 if (!try_module_get(THIS_MODULE))
1742 goto bad_module_get;
1743
1744 /* get a minor number for the dev */
1745 if (minor == DM_ANY_MINOR)
1746 r = next_free_minor(&minor);
1747 else
1748 r = specific_minor(minor);
1749 if (r < 0)
1750 goto bad_minor;
1751
1752 init_rwsem(&md->io_lock);
1753 mutex_init(&md->suspend_lock);
1754 spin_lock_init(&md->deferred_lock);
1755 rwlock_init(&md->map_lock);
1756 atomic_set(&md->holders, 1);
1757 atomic_set(&md->open_count, 0);
1758 atomic_set(&md->event_nr, 0);
1759 atomic_set(&md->uevent_seq, 0);
1760 INIT_LIST_HEAD(&md->uevent_list);
1761 spin_lock_init(&md->uevent_lock);
1762
1763 md->queue = blk_init_queue(dm_request_fn, NULL);
1764 if (!md->queue)
1765 goto bad_queue;
1766
1767 /*
1768 * Request-based dm devices cannot be stacked on top of bio-based dm
1769 * devices. The type of this dm device has not been decided yet,
1770 * although we initialized the queue using blk_init_queue().
1771 * The type is decided at the first table loading time.
1772 * To prevent problematic device stacking, clear the queue flag
1773 * for request stacking support until then.
1774 *
1775 * This queue is new, so no concurrency on the queue_flags.
1776 */
1777 queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
1778 md->saved_make_request_fn = md->queue->make_request_fn;
1779 md->queue->queuedata = md;
1780 md->queue->backing_dev_info.congested_fn = dm_any_congested;
1781 md->queue->backing_dev_info.congested_data = md;
1782 blk_queue_make_request(md->queue, dm_request);
1783 blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1784 md->queue->unplug_fn = dm_unplug_all;
1785 blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1786 blk_queue_softirq_done(md->queue, dm_softirq_done);
1787 blk_queue_prep_rq(md->queue, dm_prep_fn);
1788 blk_queue_lld_busy(md->queue, dm_lld_busy);
1789
1790 md->disk = alloc_disk(1);
1791 if (!md->disk)
1792 goto bad_disk;
1793
1794 atomic_set(&md->pending, 0);
1795 init_waitqueue_head(&md->wait);
1796 INIT_WORK(&md->work, dm_wq_work);
1797 init_waitqueue_head(&md->eventq);
1798
1799 md->disk->major = _major;
1800 md->disk->first_minor = minor;
1801 md->disk->fops = &dm_blk_dops;
1802 md->disk->queue = md->queue;
1803 md->disk->private_data = md;
1804 sprintf(md->disk->disk_name, "dm-%d", minor);
1805 add_disk(md->disk);
1806 format_dev_t(md->name, MKDEV(_major, minor));
1807
1808 md->wq = create_singlethread_workqueue("kdmflush");
1809 if (!md->wq)
1810 goto bad_thread;
1811
1812 md->bdev = bdget_disk(md->disk, 0);
1813 if (!md->bdev)
1814 goto bad_bdev;
1815
1816 /* Populate the mapping, nobody knows we exist yet */
1817 spin_lock(&_minor_lock);
1818 old_md = idr_replace(&_minor_idr, md, minor);
1819 spin_unlock(&_minor_lock);
1820
1821 BUG_ON(old_md != MINOR_ALLOCED);
1822
1823 return md;
1824
1825 bad_bdev:
1826 destroy_workqueue(md->wq);
1827 bad_thread:
1828 del_gendisk(md->disk);
1829 put_disk(md->disk);
1830 bad_disk:
1831 blk_cleanup_queue(md->queue);
1832 bad_queue:
1833 free_minor(minor);
1834 bad_minor:
1835 module_put(THIS_MODULE);
1836 bad_module_get:
1837 kfree(md);
1838 return NULL;
1839 }
1840
1841 static void unlock_fs(struct mapped_device *md);
1842
1843 static void free_dev(struct mapped_device *md)
1844 {
1845 int minor = MINOR(disk_devt(md->disk));
1846
1847 unlock_fs(md);
1848 bdput(md->bdev);
1849 destroy_workqueue(md->wq);
1850 if (md->tio_pool)
1851 mempool_destroy(md->tio_pool);
1852 if (md->io_pool)
1853 mempool_destroy(md->io_pool);
1854 if (md->bs)
1855 bioset_free(md->bs);
1856 blk_integrity_unregister(md->disk);
1857 del_gendisk(md->disk);
1858 free_minor(minor);
1859
1860 spin_lock(&_minor_lock);
1861 md->disk->private_data = NULL;
1862 spin_unlock(&_minor_lock);
1863
1864 put_disk(md->disk);
1865 blk_cleanup_queue(md->queue);
1866 module_put(THIS_MODULE);
1867 kfree(md);
1868 }
1869
1870 static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
1871 {
1872 struct dm_md_mempools *p;
1873
1874 if (md->io_pool && md->tio_pool && md->bs)
1875 /* the md already has necessary mempools */
1876 goto out;
1877
1878 p = dm_table_get_md_mempools(t);
1879 BUG_ON(!p || md->io_pool || md->tio_pool || md->bs);
1880
1881 md->io_pool = p->io_pool;
1882 p->io_pool = NULL;
1883 md->tio_pool = p->tio_pool;
1884 p->tio_pool = NULL;
1885 md->bs = p->bs;
1886 p->bs = NULL;
1887
1888 out:
1889 /* mempool bind completed, now no need any mempools in the table */
1890 dm_table_free_md_mempools(t);
1891 }
1892
1893 /*
1894 * Bind a table to the device.
1895 */
1896 static void event_callback(void *context)
1897 {
1898 unsigned long flags;
1899 LIST_HEAD(uevents);
1900 struct mapped_device *md = (struct mapped_device *) context;
1901
1902 spin_lock_irqsave(&md->uevent_lock, flags);
1903 list_splice_init(&md->uevent_list, &uevents);
1904 spin_unlock_irqrestore(&md->uevent_lock, flags);
1905
1906 dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
1907
1908 atomic_inc(&md->event_nr);
1909 wake_up(&md->eventq);
1910 }
1911
1912 static void __set_size(struct mapped_device *md, sector_t size)
1913 {
1914 set_capacity(md->disk, size);
1915
1916 mutex_lock(&md->bdev->bd_inode->i_mutex);
1917 i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
1918 mutex_unlock(&md->bdev->bd_inode->i_mutex);
1919 }
1920
1921 static int __bind(struct mapped_device *md, struct dm_table *t,
1922 struct queue_limits *limits)
1923 {
1924 struct request_queue *q = md->queue;
1925 sector_t size;
1926 unsigned long flags;
1927
1928 size = dm_table_get_size(t);
1929
1930 /*
1931 * Wipe any geometry if the size of the table changed.
1932 */
1933 if (size != get_capacity(md->disk))
1934 memset(&md->geometry, 0, sizeof(md->geometry));
1935
1936 __set_size(md, size);
1937
1938 if (!size) {
1939 dm_table_destroy(t);
1940 return 0;
1941 }
1942
1943 dm_table_event_callback(t, event_callback, md);
1944
1945 /*
1946 * The queue hasn't been stopped yet, if the old table type wasn't
1947 * for request-based during suspension. So stop it to prevent
1948 * I/O mapping before resume.
1949 * This must be done before setting the queue restrictions,
1950 * because request-based dm may be run just after the setting.
1951 */
1952 if (dm_table_request_based(t) && !blk_queue_stopped(q))
1953 stop_queue(q);
1954
1955 __bind_mempools(md, t);
1956
1957 write_lock_irqsave(&md->map_lock, flags);
1958 md->map = t;
1959 dm_table_set_restrictions(t, q, limits);
1960 write_unlock_irqrestore(&md->map_lock, flags);
1961
1962 return 0;
1963 }
1964
1965 static void __unbind(struct mapped_device *md)
1966 {
1967 struct dm_table *map = md->map;
1968 unsigned long flags;
1969
1970 if (!map)
1971 return;
1972
1973 dm_table_event_callback(map, NULL, NULL);
1974 write_lock_irqsave(&md->map_lock, flags);
1975 md->map = NULL;
1976 write_unlock_irqrestore(&md->map_lock, flags);
1977 dm_table_destroy(map);
1978 }
1979
1980 /*
1981 * Constructor for a new device.
1982 */
1983 int dm_create(int minor, struct mapped_device **result)
1984 {
1985 struct mapped_device *md;
1986
1987 md = alloc_dev(minor);
1988 if (!md)
1989 return -ENXIO;
1990
1991 dm_sysfs_init(md);
1992
1993 *result = md;
1994 return 0;
1995 }
1996
1997 static struct mapped_device *dm_find_md(dev_t dev)
1998 {
1999 struct mapped_device *md;
2000 unsigned minor = MINOR(dev);
2001
2002 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2003 return NULL;
2004
2005 spin_lock(&_minor_lock);
2006
2007 md = idr_find(&_minor_idr, minor);
2008 if (md && (md == MINOR_ALLOCED ||
2009 (MINOR(disk_devt(dm_disk(md))) != minor) ||
2010 test_bit(DMF_FREEING, &md->flags))) {
2011 md = NULL;
2012 goto out;
2013 }
2014
2015 out:
2016 spin_unlock(&_minor_lock);
2017
2018 return md;
2019 }
2020
2021 struct mapped_device *dm_get_md(dev_t dev)
2022 {
2023 struct mapped_device *md = dm_find_md(dev);
2024
2025 if (md)
2026 dm_get(md);
2027
2028 return md;
2029 }
2030
2031 void *dm_get_mdptr(struct mapped_device *md)
2032 {
2033 return md->interface_ptr;
2034 }
2035
2036 void dm_set_mdptr(struct mapped_device *md, void *ptr)
2037 {
2038 md->interface_ptr = ptr;
2039 }
2040
2041 void dm_get(struct mapped_device *md)
2042 {
2043 atomic_inc(&md->holders);
2044 }
2045
2046 const char *dm_device_name(struct mapped_device *md)
2047 {
2048 return md->name;
2049 }
2050 EXPORT_SYMBOL_GPL(dm_device_name);
2051
2052 void dm_put(struct mapped_device *md)
2053 {
2054 struct dm_table *map;
2055
2056 BUG_ON(test_bit(DMF_FREEING, &md->flags));
2057
2058 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
2059 map = dm_get_table(md);
2060 idr_replace(&_minor_idr, MINOR_ALLOCED,
2061 MINOR(disk_devt(dm_disk(md))));
2062 set_bit(DMF_FREEING, &md->flags);
2063 spin_unlock(&_minor_lock);
2064 if (!dm_suspended(md)) {
2065 dm_table_presuspend_targets(map);
2066 dm_table_postsuspend_targets(map);
2067 }
2068 dm_sysfs_exit(md);
2069 dm_table_put(map);
2070 __unbind(md);
2071 free_dev(md);
2072 }
2073 }
2074 EXPORT_SYMBOL_GPL(dm_put);
2075
2076 static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2077 {
2078 int r = 0;
2079 DECLARE_WAITQUEUE(wait, current);
2080 struct request_queue *q = md->queue;
2081 unsigned long flags;
2082
2083 dm_unplug_all(md->queue);
2084
2085 add_wait_queue(&md->wait, &wait);
2086
2087 while (1) {
2088 set_current_state(interruptible);
2089
2090 smp_mb();
2091 if (dm_request_based(md)) {
2092 spin_lock_irqsave(q->queue_lock, flags);
2093 if (!queue_in_flight(q) && blk_queue_stopped(q)) {
2094 spin_unlock_irqrestore(q->queue_lock, flags);
2095 break;
2096 }
2097 spin_unlock_irqrestore(q->queue_lock, flags);
2098 } else if (!atomic_read(&md->pending))
2099 break;
2100
2101 if (interruptible == TASK_INTERRUPTIBLE &&
2102 signal_pending(current)) {
2103 r = -EINTR;
2104 break;
2105 }
2106
2107 io_schedule();
2108 }
2109 set_current_state(TASK_RUNNING);
2110
2111 remove_wait_queue(&md->wait, &wait);
2112
2113 return r;
2114 }
2115
2116 static void dm_flush(struct mapped_device *md)
2117 {
2118 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2119
2120 bio_init(&md->barrier_bio);
2121 md->barrier_bio.bi_bdev = md->bdev;
2122 md->barrier_bio.bi_rw = WRITE_BARRIER;
2123 __split_and_process_bio(md, &md->barrier_bio);
2124
2125 dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2126 }
2127
2128 static void process_barrier(struct mapped_device *md, struct bio *bio)
2129 {
2130 md->barrier_error = 0;
2131
2132 dm_flush(md);
2133
2134 if (!bio_empty_barrier(bio)) {
2135 __split_and_process_bio(md, bio);
2136 dm_flush(md);
2137 }
2138
2139 if (md->barrier_error != DM_ENDIO_REQUEUE)
2140 bio_endio(bio, md->barrier_error);
2141 else {
2142 spin_lock_irq(&md->deferred_lock);
2143 bio_list_add_head(&md->deferred, bio);
2144 spin_unlock_irq(&md->deferred_lock);
2145 }
2146 }
2147
2148 /*
2149 * Process the deferred bios
2150 */
2151 static void dm_wq_work(struct work_struct *work)
2152 {
2153 struct mapped_device *md = container_of(work, struct mapped_device,
2154 work);
2155 struct bio *c;
2156
2157 down_write(&md->io_lock);
2158
2159 while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2160 spin_lock_irq(&md->deferred_lock);
2161 c = bio_list_pop(&md->deferred);
2162 spin_unlock_irq(&md->deferred_lock);
2163
2164 if (!c) {
2165 clear_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
2166 break;
2167 }
2168
2169 up_write(&md->io_lock);
2170
2171 if (dm_request_based(md))
2172 generic_make_request(c);
2173 else {
2174 if (bio_barrier(c))
2175 process_barrier(md, c);
2176 else
2177 __split_and_process_bio(md, c);
2178 }
2179
2180 down_write(&md->io_lock);
2181 }
2182
2183 up_write(&md->io_lock);
2184 }
2185
2186 static void dm_queue_flush(struct mapped_device *md)
2187 {
2188 clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2189 smp_mb__after_clear_bit();
2190 queue_work(md->wq, &md->work);
2191 }
2192
2193 /*
2194 * Swap in a new table (destroying old one).
2195 */
2196 int dm_swap_table(struct mapped_device *md, struct dm_table *table)
2197 {
2198 struct queue_limits limits;
2199 int r = -EINVAL;
2200
2201 mutex_lock(&md->suspend_lock);
2202
2203 /* device must be suspended */
2204 if (!dm_suspended(md))
2205 goto out;
2206
2207 r = dm_calculate_queue_limits(table, &limits);
2208 if (r)
2209 goto out;
2210
2211 /* cannot change the device type, once a table is bound */
2212 if (md->map &&
2213 (dm_table_get_type(md->map) != dm_table_get_type(table))) {
2214 DMWARN("can't change the device type after a table is bound");
2215 goto out;
2216 }
2217
2218 __unbind(md);
2219 r = __bind(md, table, &limits);
2220
2221 out:
2222 mutex_unlock(&md->suspend_lock);
2223 return r;
2224 }
2225
2226 static void dm_rq_invalidate_suspend_marker(struct mapped_device *md)
2227 {
2228 md->suspend_rq.special = (void *)0x1;
2229 }
2230
2231 static void dm_rq_abort_suspend(struct mapped_device *md, int noflush)
2232 {
2233 struct request_queue *q = md->queue;
2234 unsigned long flags;
2235
2236 spin_lock_irqsave(q->queue_lock, flags);
2237 if (!noflush)
2238 dm_rq_invalidate_suspend_marker(md);
2239 __start_queue(q);
2240 spin_unlock_irqrestore(q->queue_lock, flags);
2241 }
2242
2243 static void dm_rq_start_suspend(struct mapped_device *md, int noflush)
2244 {
2245 struct request *rq = &md->suspend_rq;
2246 struct request_queue *q = md->queue;
2247
2248 if (noflush)
2249 stop_queue(q);
2250 else {
2251 blk_rq_init(q, rq);
2252 blk_insert_request(q, rq, 0, NULL);
2253 }
2254 }
2255
2256 static int dm_rq_suspend_available(struct mapped_device *md, int noflush)
2257 {
2258 int r = 1;
2259 struct request *rq = &md->suspend_rq;
2260 struct request_queue *q = md->queue;
2261 unsigned long flags;
2262
2263 if (noflush)
2264 return r;
2265
2266 /* The marker must be protected by queue lock if it is in use */
2267 spin_lock_irqsave(q->queue_lock, flags);
2268 if (unlikely(rq->ref_count)) {
2269 /*
2270 * This can happen, when the previous flush suspend was
2271 * interrupted, the marker is still in the queue and
2272 * this flush suspend has been invoked, because we don't
2273 * remove the marker at the time of suspend interruption.
2274 * We have only one marker per mapped_device, so we can't
2275 * start another flush suspend while it is in use.
2276 */
2277 BUG_ON(!rq->special); /* The marker should be invalidated */
2278 DMWARN("Invalidating the previous flush suspend is still in"
2279 " progress. Please retry later.");
2280 r = 0;
2281 }
2282 spin_unlock_irqrestore(q->queue_lock, flags);
2283
2284 return r;
2285 }
2286
2287 /*
2288 * Functions to lock and unlock any filesystem running on the
2289 * device.
2290 */
2291 static int lock_fs(struct mapped_device *md)
2292 {
2293 int r;
2294
2295 WARN_ON(md->frozen_sb);
2296
2297 md->frozen_sb = freeze_bdev(md->bdev);
2298 if (IS_ERR(md->frozen_sb)) {
2299 r = PTR_ERR(md->frozen_sb);
2300 md->frozen_sb = NULL;
2301 return r;
2302 }
2303
2304 set_bit(DMF_FROZEN, &md->flags);
2305
2306 return 0;
2307 }
2308
2309 static void unlock_fs(struct mapped_device *md)
2310 {
2311 if (!test_bit(DMF_FROZEN, &md->flags))
2312 return;
2313
2314 thaw_bdev(md->bdev, md->frozen_sb);
2315 md->frozen_sb = NULL;
2316 clear_bit(DMF_FROZEN, &md->flags);
2317 }
2318
2319 /*
2320 * We need to be able to change a mapping table under a mounted
2321 * filesystem. For example we might want to move some data in
2322 * the background. Before the table can be swapped with
2323 * dm_bind_table, dm_suspend must be called to flush any in
2324 * flight bios and ensure that any further io gets deferred.
2325 */
2326 /*
2327 * Suspend mechanism in request-based dm.
2328 *
2329 * After the suspend starts, further incoming requests are kept in
2330 * the request_queue and deferred.
2331 * Remaining requests in the request_queue at the start of suspend are flushed
2332 * if it is flush suspend.
2333 * The suspend completes when the following conditions have been satisfied,
2334 * so wait for it:
2335 * 1. q->in_flight is 0 (which means no in_flight request)
2336 * 2. queue has been stopped (which means no request dispatching)
2337 *
2338 *
2339 * Noflush suspend
2340 * ---------------
2341 * Noflush suspend doesn't need to dispatch remaining requests.
2342 * So stop the queue immediately. Then, wait for all in_flight requests
2343 * to be completed or requeued.
2344 *
2345 * To abort noflush suspend, start the queue.
2346 *
2347 *
2348 * Flush suspend
2349 * -------------
2350 * Flush suspend needs to dispatch remaining requests. So stop the queue
2351 * after the remaining requests are completed. (Requeued request must be also
2352 * re-dispatched and completed. Until then, we can't stop the queue.)
2353 *
2354 * During flushing the remaining requests, further incoming requests are also
2355 * inserted to the same queue. To distinguish which requests are to be
2356 * flushed, we insert a marker request to the queue at the time of starting
2357 * flush suspend, like a barrier.
2358 * The dispatching is blocked when the marker is found on the top of the queue.
2359 * And the queue is stopped when all in_flight requests are completed, since
2360 * that means the remaining requests are completely flushed.
2361 * Then, the marker is removed from the queue.
2362 *
2363 * To abort flush suspend, we also need to take care of the marker, not only
2364 * starting the queue.
2365 * We don't remove the marker forcibly from the queue since it's against
2366 * the block-layer manner. Instead, we put a invalidated mark on the marker.
2367 * When the invalidated marker is found on the top of the queue, it is
2368 * immediately removed from the queue, so it doesn't block dispatching.
2369 * Because we have only one marker per mapped_device, we can't start another
2370 * flush suspend until the invalidated marker is removed from the queue.
2371 * So fail and return with -EBUSY in such a case.
2372 */
2373 int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
2374 {
2375 struct dm_table *map = NULL;
2376 int r = 0;
2377 int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
2378 int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
2379
2380 mutex_lock(&md->suspend_lock);
2381
2382 if (dm_suspended(md)) {
2383 r = -EINVAL;
2384 goto out_unlock;
2385 }
2386
2387 if (dm_request_based(md) && !dm_rq_suspend_available(md, noflush)) {
2388 r = -EBUSY;
2389 goto out_unlock;
2390 }
2391
2392 map = dm_get_table(md);
2393
2394 /*
2395 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2396 * This flag is cleared before dm_suspend returns.
2397 */
2398 if (noflush)
2399 set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2400
2401 /* This does not get reverted if there's an error later. */
2402 dm_table_presuspend_targets(map);
2403
2404 /*
2405 * Flush I/O to the device. noflush supersedes do_lockfs,
2406 * because lock_fs() needs to flush I/Os.
2407 */
2408 if (!noflush && do_lockfs) {
2409 r = lock_fs(md);
2410 if (r)
2411 goto out;
2412 }
2413
2414 /*
2415 * Here we must make sure that no processes are submitting requests
2416 * to target drivers i.e. no one may be executing
2417 * __split_and_process_bio. This is called from dm_request and
2418 * dm_wq_work.
2419 *
2420 * To get all processes out of __split_and_process_bio in dm_request,
2421 * we take the write lock. To prevent any process from reentering
2422 * __split_and_process_bio from dm_request, we set
2423 * DMF_QUEUE_IO_TO_THREAD.
2424 *
2425 * To quiesce the thread (dm_wq_work), we set DMF_BLOCK_IO_FOR_SUSPEND
2426 * and call flush_workqueue(md->wq). flush_workqueue will wait until
2427 * dm_wq_work exits and DMF_BLOCK_IO_FOR_SUSPEND will prevent any
2428 * further calls to __split_and_process_bio from dm_wq_work.
2429 */
2430 down_write(&md->io_lock);
2431 set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2432 set_bit(DMF_QUEUE_IO_TO_THREAD, &md->flags);
2433 up_write(&md->io_lock);
2434
2435 flush_workqueue(md->wq);
2436
2437 if (dm_request_based(md))
2438 dm_rq_start_suspend(md, noflush);
2439
2440 /*
2441 * At this point no more requests are entering target request routines.
2442 * We call dm_wait_for_completion to wait for all existing requests
2443 * to finish.
2444 */
2445 r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
2446
2447 down_write(&md->io_lock);
2448 if (noflush)
2449 clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2450 up_write(&md->io_lock);
2451
2452 /* were we interrupted ? */
2453 if (r < 0) {
2454 dm_queue_flush(md);
2455
2456 if (dm_request_based(md))
2457 dm_rq_abort_suspend(md, noflush);
2458
2459 unlock_fs(md);
2460 goto out; /* pushback list is already flushed, so skip flush */
2461 }
2462
2463 /*
2464 * If dm_wait_for_completion returned 0, the device is completely
2465 * quiescent now. There is no request-processing activity. All new
2466 * requests are being added to md->deferred list.
2467 */
2468
2469 dm_table_postsuspend_targets(map);
2470
2471 set_bit(DMF_SUSPENDED, &md->flags);
2472
2473 out:
2474 dm_table_put(map);
2475
2476 out_unlock:
2477 mutex_unlock(&md->suspend_lock);
2478 return r;
2479 }
2480
2481 int dm_resume(struct mapped_device *md)
2482 {
2483 int r = -EINVAL;
2484 struct dm_table *map = NULL;
2485
2486 mutex_lock(&md->suspend_lock);
2487 if (!dm_suspended(md))
2488 goto out;
2489
2490 map = dm_get_table(md);
2491 if (!map || !dm_table_get_size(map))
2492 goto out;
2493
2494 r = dm_table_resume_targets(map);
2495 if (r)
2496 goto out;
2497
2498 dm_queue_flush(md);
2499
2500 /*
2501 * Flushing deferred I/Os must be done after targets are resumed
2502 * so that mapping of targets can work correctly.
2503 * Request-based dm is queueing the deferred I/Os in its request_queue.
2504 */
2505 if (dm_request_based(md))
2506 start_queue(md->queue);
2507
2508 unlock_fs(md);
2509
2510 clear_bit(DMF_SUSPENDED, &md->flags);
2511
2512 dm_table_unplug_all(map);
2513 r = 0;
2514 out:
2515 dm_table_put(map);
2516 mutex_unlock(&md->suspend_lock);
2517
2518 return r;
2519 }
2520
2521 /*-----------------------------------------------------------------
2522 * Event notification.
2523 *---------------------------------------------------------------*/
2524 void dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
2525 unsigned cookie)
2526 {
2527 char udev_cookie[DM_COOKIE_LENGTH];
2528 char *envp[] = { udev_cookie, NULL };
2529
2530 if (!cookie)
2531 kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
2532 else {
2533 snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
2534 DM_COOKIE_ENV_VAR_NAME, cookie);
2535 kobject_uevent_env(&disk_to_dev(md->disk)->kobj, action, envp);
2536 }
2537 }
2538
2539 uint32_t dm_next_uevent_seq(struct mapped_device *md)
2540 {
2541 return atomic_add_return(1, &md->uevent_seq);
2542 }
2543
2544 uint32_t dm_get_event_nr(struct mapped_device *md)
2545 {
2546 return atomic_read(&md->event_nr);
2547 }
2548
2549 int dm_wait_event(struct mapped_device *md, int event_nr)
2550 {
2551 return wait_event_interruptible(md->eventq,
2552 (event_nr != atomic_read(&md->event_nr)));
2553 }
2554
2555 void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
2556 {
2557 unsigned long flags;
2558
2559 spin_lock_irqsave(&md->uevent_lock, flags);
2560 list_add(elist, &md->uevent_list);
2561 spin_unlock_irqrestore(&md->uevent_lock, flags);
2562 }
2563
2564 /*
2565 * The gendisk is only valid as long as you have a reference
2566 * count on 'md'.
2567 */
2568 struct gendisk *dm_disk(struct mapped_device *md)
2569 {
2570 return md->disk;
2571 }
2572
2573 struct kobject *dm_kobject(struct mapped_device *md)
2574 {
2575 return &md->kobj;
2576 }
2577
2578 /*
2579 * struct mapped_device should not be exported outside of dm.c
2580 * so use this check to verify that kobj is part of md structure
2581 */
2582 struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
2583 {
2584 struct mapped_device *md;
2585
2586 md = container_of(kobj, struct mapped_device, kobj);
2587 if (&md->kobj != kobj)
2588 return NULL;
2589
2590 if (test_bit(DMF_FREEING, &md->flags) ||
2591 test_bit(DMF_DELETING, &md->flags))
2592 return NULL;
2593
2594 dm_get(md);
2595 return md;
2596 }
2597
2598 int dm_suspended(struct mapped_device *md)
2599 {
2600 return test_bit(DMF_SUSPENDED, &md->flags);
2601 }
2602
2603 int dm_noflush_suspending(struct dm_target *ti)
2604 {
2605 struct mapped_device *md = dm_table_get_md(ti->table);
2606 int r = __noflush_suspending(md);
2607
2608 dm_put(md);
2609
2610 return r;
2611 }
2612 EXPORT_SYMBOL_GPL(dm_noflush_suspending);
2613
2614 struct dm_md_mempools *dm_alloc_md_mempools(unsigned type)
2615 {
2616 struct dm_md_mempools *pools = kmalloc(sizeof(*pools), GFP_KERNEL);
2617
2618 if (!pools)
2619 return NULL;
2620
2621 pools->io_pool = (type == DM_TYPE_BIO_BASED) ?
2622 mempool_create_slab_pool(MIN_IOS, _io_cache) :
2623 mempool_create_slab_pool(MIN_IOS, _rq_bio_info_cache);
2624 if (!pools->io_pool)
2625 goto free_pools_and_out;
2626
2627 pools->tio_pool = (type == DM_TYPE_BIO_BASED) ?
2628 mempool_create_slab_pool(MIN_IOS, _tio_cache) :
2629 mempool_create_slab_pool(MIN_IOS, _rq_tio_cache);
2630 if (!pools->tio_pool)
2631 goto free_io_pool_and_out;
2632
2633 pools->bs = (type == DM_TYPE_BIO_BASED) ?
2634 bioset_create(16, 0) : bioset_create(MIN_IOS, 0);
2635 if (!pools->bs)
2636 goto free_tio_pool_and_out;
2637
2638 return pools;
2639
2640 free_tio_pool_and_out:
2641 mempool_destroy(pools->tio_pool);
2642
2643 free_io_pool_and_out:
2644 mempool_destroy(pools->io_pool);
2645
2646 free_pools_and_out:
2647 kfree(pools);
2648
2649 return NULL;
2650 }
2651
2652 void dm_free_md_mempools(struct dm_md_mempools *pools)
2653 {
2654 if (!pools)
2655 return;
2656
2657 if (pools->io_pool)
2658 mempool_destroy(pools->io_pool);
2659
2660 if (pools->tio_pool)
2661 mempool_destroy(pools->tio_pool);
2662
2663 if (pools->bs)
2664 bioset_free(pools->bs);
2665
2666 kfree(pools);
2667 }
2668
2669 static struct block_device_operations dm_blk_dops = {
2670 .open = dm_blk_open,
2671 .release = dm_blk_close,
2672 .ioctl = dm_blk_ioctl,
2673 .getgeo = dm_blk_getgeo,
2674 .owner = THIS_MODULE
2675 };
2676
2677 EXPORT_SYMBOL(dm_get_mapinfo);
2678
2679 /*
2680 * module hooks
2681 */
2682 module_init(dm_init);
2683 module_exit(dm_exit);
2684
2685 module_param(major, uint, 0);
2686 MODULE_PARM_DESC(major, "The major number of the device mapper");
2687 MODULE_DESCRIPTION(DM_NAME " driver");
2688 MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2689 MODULE_LICENSE("GPL");
2690
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