blob: 1ca7463e8bb2b26c799f63f5d54a4a33d570704c [file] [log] [blame]
Mike Snitzer4cc96132016-05-12 16:28:10 -04001/*
2 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
3 *
4 * This file is released under the GPL.
5 */
6
7#include "dm-core.h"
8#include "dm-rq.h"
9
10#include <linux/elevator.h> /* for rq_end_sector() */
11#include <linux/blk-mq.h>
12
13#define DM_MSG_PREFIX "core-rq"
14
15#define DM_MQ_NR_HW_QUEUES 1
16#define DM_MQ_QUEUE_DEPTH 2048
17static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
18static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
19
20/*
21 * Request-based DM's mempools' reserved IOs set by the user.
22 */
23#define RESERVED_REQUEST_BASED_IOS 256
24static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
25
26#ifdef CONFIG_DM_MQ_DEFAULT
27static bool use_blk_mq = true;
28#else
29static bool use_blk_mq = false;
30#endif
31
32bool dm_use_blk_mq_default(void)
33{
34 return use_blk_mq;
35}
36
37bool dm_use_blk_mq(struct mapped_device *md)
38{
39 return md->use_blk_mq;
40}
41EXPORT_SYMBOL_GPL(dm_use_blk_mq);
42
43unsigned dm_get_reserved_rq_based_ios(void)
44{
45 return __dm_get_module_param(&reserved_rq_based_ios,
46 RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS);
47}
48EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
49
50static unsigned dm_get_blk_mq_nr_hw_queues(void)
51{
52 return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);
53}
54
55static unsigned dm_get_blk_mq_queue_depth(void)
56{
57 return __dm_get_module_param(&dm_mq_queue_depth,
58 DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);
59}
60
61int dm_request_based(struct mapped_device *md)
62{
63 return blk_queue_stackable(md->queue);
64}
65
66static void dm_old_start_queue(struct request_queue *q)
67{
68 unsigned long flags;
69
70 spin_lock_irqsave(q->queue_lock, flags);
71 if (blk_queue_stopped(q))
72 blk_start_queue(q);
73 spin_unlock_irqrestore(q->queue_lock, flags);
74}
75
76void dm_start_queue(struct request_queue *q)
77{
78 if (!q->mq_ops)
79 dm_old_start_queue(q);
80 else {
Mike Snitzer7d9595d2016-08-02 12:51:11 -040081 queue_flag_clear_unlocked(QUEUE_FLAG_STOPPED, q);
Mike Snitzer4cc96132016-05-12 16:28:10 -040082 blk_mq_start_stopped_hw_queues(q, true);
83 blk_mq_kick_requeue_list(q);
84 }
85}
86
87static void dm_old_stop_queue(struct request_queue *q)
88{
89 unsigned long flags;
90
91 spin_lock_irqsave(q->queue_lock, flags);
92 if (blk_queue_stopped(q)) {
93 spin_unlock_irqrestore(q->queue_lock, flags);
94 return;
95 }
96
97 blk_stop_queue(q);
98 spin_unlock_irqrestore(q->queue_lock, flags);
99}
100
101void dm_stop_queue(struct request_queue *q)
102{
103 if (!q->mq_ops)
104 dm_old_stop_queue(q);
Mike Snitzer7d9595d2016-08-02 12:51:11 -0400105 else {
106 spin_lock_irq(q->queue_lock);
107 queue_flag_set(QUEUE_FLAG_STOPPED, q);
108 spin_unlock_irq(q->queue_lock);
109
110 blk_mq_cancel_requeue_work(q);
Mike Snitzer4cc96132016-05-12 16:28:10 -0400111 blk_mq_stop_hw_queues(q);
Mike Snitzer7d9595d2016-08-02 12:51:11 -0400112 }
Mike Snitzer4cc96132016-05-12 16:28:10 -0400113}
114
115static struct dm_rq_target_io *alloc_old_rq_tio(struct mapped_device *md,
116 gfp_t gfp_mask)
117{
118 return mempool_alloc(md->io_pool, gfp_mask);
119}
120
121static void free_old_rq_tio(struct dm_rq_target_io *tio)
122{
123 mempool_free(tio, tio->md->io_pool);
124}
125
126static struct request *alloc_old_clone_request(struct mapped_device *md,
127 gfp_t gfp_mask)
128{
129 return mempool_alloc(md->rq_pool, gfp_mask);
130}
131
132static void free_old_clone_request(struct mapped_device *md, struct request *rq)
133{
134 mempool_free(rq, md->rq_pool);
135}
136
137/*
138 * Partial completion handling for request-based dm
139 */
140static void end_clone_bio(struct bio *clone)
141{
142 struct dm_rq_clone_bio_info *info =
143 container_of(clone, struct dm_rq_clone_bio_info, clone);
144 struct dm_rq_target_io *tio = info->tio;
145 struct bio *bio = info->orig;
146 unsigned int nr_bytes = info->orig->bi_iter.bi_size;
147 int error = clone->bi_error;
148
149 bio_put(clone);
150
151 if (tio->error)
152 /*
153 * An error has already been detected on the request.
154 * Once error occurred, just let clone->end_io() handle
155 * the remainder.
156 */
157 return;
158 else if (error) {
159 /*
160 * Don't notice the error to the upper layer yet.
161 * The error handling decision is made by the target driver,
162 * when the request is completed.
163 */
164 tio->error = error;
165 return;
166 }
167
168 /*
169 * I/O for the bio successfully completed.
170 * Notice the data completion to the upper layer.
171 */
172
173 /*
174 * bios are processed from the head of the list.
175 * So the completing bio should always be rq->bio.
176 * If it's not, something wrong is happening.
177 */
178 if (tio->orig->bio != bio)
179 DMERR("bio completion is going in the middle of the request");
180
181 /*
182 * Update the original request.
183 * Do not use blk_end_request() here, because it may complete
184 * the original request before the clone, and break the ordering.
185 */
186 blk_update_request(tio->orig, 0, nr_bytes);
187}
188
189static struct dm_rq_target_io *tio_from_request(struct request *rq)
190{
191 return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special);
192}
193
194static void rq_end_stats(struct mapped_device *md, struct request *orig)
195{
196 if (unlikely(dm_stats_used(&md->stats))) {
197 struct dm_rq_target_io *tio = tio_from_request(orig);
198 tio->duration_jiffies = jiffies - tio->duration_jiffies;
199 dm_stats_account_io(&md->stats, rq_data_dir(orig),
200 blk_rq_pos(orig), tio->n_sectors, true,
201 tio->duration_jiffies, &tio->stats_aux);
202 }
203}
204
205/*
206 * Don't touch any member of the md after calling this function because
207 * the md may be freed in dm_put() at the end of this function.
208 * Or do dm_get() before calling this function and dm_put() later.
209 */
210static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
211{
212 atomic_dec(&md->pending[rw]);
213
214 /* nudge anyone waiting on suspend queue */
215 if (!md_in_flight(md))
216 wake_up(&md->wait);
217
218 /*
219 * Run this off this callpath, as drivers could invoke end_io while
220 * inside their request_fn (and holding the queue lock). Calling
221 * back into ->request_fn() could deadlock attempting to grab the
222 * queue lock again.
223 */
224 if (!md->queue->mq_ops && run_queue)
225 blk_run_queue_async(md->queue);
226
227 /*
228 * dm_put() must be at the end of this function. See the comment above
229 */
230 dm_put(md);
231}
232
233static void free_rq_clone(struct request *clone)
234{
235 struct dm_rq_target_io *tio = clone->end_io_data;
236 struct mapped_device *md = tio->md;
237
238 blk_rq_unprep_clone(clone);
239
Mike Snitzere83068a2016-05-24 21:16:51 -0400240 /*
241 * It is possible for a clone_old_rq() allocated clone to
242 * get passed in -- it may not yet have a request_queue.
243 * This is known to occur if the error target replaces
244 * a multipath target that has a request_fn queue stacked
245 * on blk-mq queue(s).
246 */
247 if (clone->q && clone->q->mq_ops)
Mike Snitzer4cc96132016-05-12 16:28:10 -0400248 /* stacked on blk-mq queue(s) */
249 tio->ti->type->release_clone_rq(clone);
250 else if (!md->queue->mq_ops)
251 /* request_fn queue stacked on request_fn queue(s) */
252 free_old_clone_request(md, clone);
253
254 if (!md->queue->mq_ops)
255 free_old_rq_tio(tio);
256}
257
258/*
259 * Complete the clone and the original request.
260 * Must be called without clone's queue lock held,
261 * see end_clone_request() for more details.
262 */
263static void dm_end_request(struct request *clone, int error)
264{
265 int rw = rq_data_dir(clone);
266 struct dm_rq_target_io *tio = clone->end_io_data;
267 struct mapped_device *md = tio->md;
268 struct request *rq = tio->orig;
269
270 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
271 rq->errors = clone->errors;
272 rq->resid_len = clone->resid_len;
273
274 if (rq->sense)
275 /*
276 * We are using the sense buffer of the original
277 * request.
278 * So setting the length of the sense data is enough.
279 */
280 rq->sense_len = clone->sense_len;
281 }
282
283 free_rq_clone(clone);
284 rq_end_stats(md, rq);
285 if (!rq->q->mq_ops)
286 blk_end_request_all(rq, error);
287 else
288 blk_mq_end_request(rq, error);
289 rq_completed(md, rw, true);
290}
291
292static void dm_unprep_request(struct request *rq)
293{
294 struct dm_rq_target_io *tio = tio_from_request(rq);
295 struct request *clone = tio->clone;
296
297 if (!rq->q->mq_ops) {
298 rq->special = NULL;
299 rq->cmd_flags &= ~REQ_DONTPREP;
300 }
301
302 if (clone)
303 free_rq_clone(clone);
304 else if (!tio->md->queue->mq_ops)
305 free_old_rq_tio(tio);
306}
307
308/*
309 * Requeue the original request of a clone.
310 */
311static void dm_old_requeue_request(struct request *rq)
312{
313 struct request_queue *q = rq->q;
314 unsigned long flags;
315
316 spin_lock_irqsave(q->queue_lock, flags);
317 blk_requeue_request(q, rq);
318 blk_run_queue_async(q);
319 spin_unlock_irqrestore(q->queue_lock, flags);
320}
321
322static void dm_mq_requeue_request(struct request *rq)
323{
324 struct request_queue *q = rq->q;
325 unsigned long flags;
326
327 blk_mq_requeue_request(rq);
328 spin_lock_irqsave(q->queue_lock, flags);
329 if (!blk_queue_stopped(q))
330 blk_mq_kick_requeue_list(q);
331 spin_unlock_irqrestore(q->queue_lock, flags);
332}
333
334static void dm_requeue_original_request(struct mapped_device *md,
335 struct request *rq)
336{
337 int rw = rq_data_dir(rq);
338
339 rq_end_stats(md, rq);
340 dm_unprep_request(rq);
341
342 if (!rq->q->mq_ops)
343 dm_old_requeue_request(rq);
344 else
345 dm_mq_requeue_request(rq);
346
347 rq_completed(md, rw, false);
348}
349
350static void dm_done(struct request *clone, int error, bool mapped)
351{
352 int r = error;
353 struct dm_rq_target_io *tio = clone->end_io_data;
354 dm_request_endio_fn rq_end_io = NULL;
355
356 if (tio->ti) {
357 rq_end_io = tio->ti->type->rq_end_io;
358
359 if (mapped && rq_end_io)
360 r = rq_end_io(tio->ti, clone, error, &tio->info);
361 }
362
363 if (unlikely(r == -EREMOTEIO && (req_op(clone) == REQ_OP_WRITE_SAME) &&
364 !clone->q->limits.max_write_same_sectors))
365 disable_write_same(tio->md);
366
367 if (r <= 0)
368 /* The target wants to complete the I/O */
369 dm_end_request(clone, r);
370 else if (r == DM_ENDIO_INCOMPLETE)
371 /* The target will handle the I/O */
372 return;
373 else if (r == DM_ENDIO_REQUEUE)
374 /* The target wants to requeue the I/O */
375 dm_requeue_original_request(tio->md, tio->orig);
376 else {
377 DMWARN("unimplemented target endio return value: %d", r);
378 BUG();
379 }
380}
381
382/*
383 * Request completion handler for request-based dm
384 */
385static void dm_softirq_done(struct request *rq)
386{
387 bool mapped = true;
388 struct dm_rq_target_io *tio = tio_from_request(rq);
389 struct request *clone = tio->clone;
390 int rw;
391
392 if (!clone) {
393 rq_end_stats(tio->md, rq);
394 rw = rq_data_dir(rq);
395 if (!rq->q->mq_ops) {
396 blk_end_request_all(rq, tio->error);
397 rq_completed(tio->md, rw, false);
398 free_old_rq_tio(tio);
399 } else {
400 blk_mq_end_request(rq, tio->error);
401 rq_completed(tio->md, rw, false);
402 }
403 return;
404 }
405
406 if (rq->cmd_flags & REQ_FAILED)
407 mapped = false;
408
409 dm_done(clone, tio->error, mapped);
410}
411
412/*
413 * Complete the clone and the original request with the error status
414 * through softirq context.
415 */
416static void dm_complete_request(struct request *rq, int error)
417{
418 struct dm_rq_target_io *tio = tio_from_request(rq);
419
420 tio->error = error;
421 if (!rq->q->mq_ops)
422 blk_complete_request(rq);
423 else
424 blk_mq_complete_request(rq, error);
425}
426
427/*
428 * Complete the not-mapped clone and the original request with the error status
429 * through softirq context.
430 * Target's rq_end_io() function isn't called.
431 * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
432 */
433static void dm_kill_unmapped_request(struct request *rq, int error)
434{
435 rq->cmd_flags |= REQ_FAILED;
436 dm_complete_request(rq, error);
437}
438
439/*
440 * Called with the clone's queue lock held (in the case of .request_fn)
441 */
442static void end_clone_request(struct request *clone, int error)
443{
444 struct dm_rq_target_io *tio = clone->end_io_data;
445
446 if (!clone->q->mq_ops) {
447 /*
448 * For just cleaning up the information of the queue in which
449 * the clone was dispatched.
450 * The clone is *NOT* freed actually here because it is alloced
451 * from dm own mempool (REQ_ALLOCED isn't set).
452 */
453 __blk_put_request(clone->q, clone);
454 }
455
456 /*
457 * Actual request completion is done in a softirq context which doesn't
458 * hold the clone's queue lock. Otherwise, deadlock could occur because:
459 * - another request may be submitted by the upper level driver
460 * of the stacking during the completion
461 * - the submission which requires queue lock may be done
462 * against this clone's queue
463 */
464 dm_complete_request(tio->orig, error);
465}
466
467static void dm_dispatch_clone_request(struct request *clone, struct request *rq)
468{
469 int r;
470
471 if (blk_queue_io_stat(clone->q))
472 clone->cmd_flags |= REQ_IO_STAT;
473
474 clone->start_time = jiffies;
475 r = blk_insert_cloned_request(clone->q, clone);
476 if (r)
477 /* must complete clone in terms of original request */
478 dm_complete_request(rq, r);
479}
480
481static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
482 void *data)
483{
484 struct dm_rq_target_io *tio = data;
485 struct dm_rq_clone_bio_info *info =
486 container_of(bio, struct dm_rq_clone_bio_info, clone);
487
488 info->orig = bio_orig;
489 info->tio = tio;
490 bio->bi_end_io = end_clone_bio;
491
492 return 0;
493}
494
495static int setup_clone(struct request *clone, struct request *rq,
496 struct dm_rq_target_io *tio, gfp_t gfp_mask)
497{
498 int r;
499
500 r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask,
501 dm_rq_bio_constructor, tio);
502 if (r)
503 return r;
504
505 clone->cmd = rq->cmd;
506 clone->cmd_len = rq->cmd_len;
507 clone->sense = rq->sense;
508 clone->end_io = end_clone_request;
509 clone->end_io_data = tio;
510
511 tio->clone = clone;
512
513 return 0;
514}
515
516static struct request *clone_old_rq(struct request *rq, struct mapped_device *md,
517 struct dm_rq_target_io *tio, gfp_t gfp_mask)
518{
519 /*
520 * Create clone for use with .request_fn request_queue
521 */
522 struct request *clone;
523
524 clone = alloc_old_clone_request(md, gfp_mask);
525 if (!clone)
526 return NULL;
527
528 blk_rq_init(NULL, clone);
529 if (setup_clone(clone, rq, tio, gfp_mask)) {
530 /* -ENOMEM */
531 free_old_clone_request(md, clone);
532 return NULL;
533 }
534
535 return clone;
536}
537
538static void map_tio_request(struct kthread_work *work);
539
540static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
541 struct mapped_device *md)
542{
543 tio->md = md;
544 tio->ti = NULL;
545 tio->clone = NULL;
546 tio->orig = rq;
547 tio->error = 0;
548 /*
549 * Avoid initializing info for blk-mq; it passes
550 * target-specific data through info.ptr
551 * (see: dm_mq_init_request)
552 */
553 if (!md->init_tio_pdu)
554 memset(&tio->info, 0, sizeof(tio->info));
555 if (md->kworker_task)
556 init_kthread_work(&tio->work, map_tio_request);
557}
558
559static struct dm_rq_target_io *dm_old_prep_tio(struct request *rq,
560 struct mapped_device *md,
561 gfp_t gfp_mask)
562{
563 struct dm_rq_target_io *tio;
564 int srcu_idx;
565 struct dm_table *table;
566
567 tio = alloc_old_rq_tio(md, gfp_mask);
568 if (!tio)
569 return NULL;
570
571 init_tio(tio, rq, md);
572
573 table = dm_get_live_table(md, &srcu_idx);
574 /*
575 * Must clone a request if this .request_fn DM device
576 * is stacked on .request_fn device(s).
577 */
Mike Snitzere83068a2016-05-24 21:16:51 -0400578 if (!dm_table_all_blk_mq_devices(table)) {
Mike Snitzer4cc96132016-05-12 16:28:10 -0400579 if (!clone_old_rq(rq, md, tio, gfp_mask)) {
580 dm_put_live_table(md, srcu_idx);
581 free_old_rq_tio(tio);
582 return NULL;
583 }
584 }
585 dm_put_live_table(md, srcu_idx);
586
587 return tio;
588}
589
590/*
591 * Called with the queue lock held.
592 */
593static int dm_old_prep_fn(struct request_queue *q, struct request *rq)
594{
595 struct mapped_device *md = q->queuedata;
596 struct dm_rq_target_io *tio;
597
598 if (unlikely(rq->special)) {
599 DMWARN("Already has something in rq->special.");
600 return BLKPREP_KILL;
601 }
602
603 tio = dm_old_prep_tio(rq, md, GFP_ATOMIC);
604 if (!tio)
605 return BLKPREP_DEFER;
606
607 rq->special = tio;
608 rq->cmd_flags |= REQ_DONTPREP;
609
610 return BLKPREP_OK;
611}
612
613/*
614 * Returns:
615 * 0 : the request has been processed
616 * DM_MAPIO_REQUEUE : the original request needs to be requeued
617 * < 0 : the request was completed due to failure
618 */
619static int map_request(struct dm_rq_target_io *tio, struct request *rq,
620 struct mapped_device *md)
621{
622 int r;
623 struct dm_target *ti = tio->ti;
624 struct request *clone = NULL;
625
626 if (tio->clone) {
627 clone = tio->clone;
628 r = ti->type->map_rq(ti, clone, &tio->info);
629 } else {
630 r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
631 if (r < 0) {
632 /* The target wants to complete the I/O */
633 dm_kill_unmapped_request(rq, r);
634 return r;
635 }
636 if (r != DM_MAPIO_REMAPPED)
637 return r;
638 if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
639 /* -ENOMEM */
640 ti->type->release_clone_rq(clone);
641 return DM_MAPIO_REQUEUE;
642 }
643 }
644
645 switch (r) {
646 case DM_MAPIO_SUBMITTED:
647 /* The target has taken the I/O to submit by itself later */
648 break;
649 case DM_MAPIO_REMAPPED:
650 /* The target has remapped the I/O so dispatch it */
651 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
652 blk_rq_pos(rq));
653 dm_dispatch_clone_request(clone, rq);
654 break;
655 case DM_MAPIO_REQUEUE:
656 /* The target wants to requeue the I/O */
657 dm_requeue_original_request(md, tio->orig);
658 break;
659 default:
660 if (r > 0) {
661 DMWARN("unimplemented target map return value: %d", r);
662 BUG();
663 }
664
665 /* The target wants to complete the I/O */
666 dm_kill_unmapped_request(rq, r);
667 return r;
668 }
669
670 return 0;
671}
672
673static void dm_start_request(struct mapped_device *md, struct request *orig)
674{
675 if (!orig->q->mq_ops)
676 blk_start_request(orig);
677 else
678 blk_mq_start_request(orig);
679 atomic_inc(&md->pending[rq_data_dir(orig)]);
680
681 if (md->seq_rq_merge_deadline_usecs) {
682 md->last_rq_pos = rq_end_sector(orig);
683 md->last_rq_rw = rq_data_dir(orig);
684 md->last_rq_start_time = ktime_get();
685 }
686
687 if (unlikely(dm_stats_used(&md->stats))) {
688 struct dm_rq_target_io *tio = tio_from_request(orig);
689 tio->duration_jiffies = jiffies;
690 tio->n_sectors = blk_rq_sectors(orig);
691 dm_stats_account_io(&md->stats, rq_data_dir(orig),
692 blk_rq_pos(orig), tio->n_sectors, false, 0,
693 &tio->stats_aux);
694 }
695
696 /*
697 * Hold the md reference here for the in-flight I/O.
698 * We can't rely on the reference count by device opener,
699 * because the device may be closed during the request completion
700 * when all bios are completed.
701 * See the comment in rq_completed() too.
702 */
703 dm_get(md);
704}
705
706static void map_tio_request(struct kthread_work *work)
707{
708 struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
709 struct request *rq = tio->orig;
710 struct mapped_device *md = tio->md;
711
712 if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE)
713 dm_requeue_original_request(md, rq);
714}
715
716ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
717{
718 return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs);
719}
720
721#define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
722
723ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
724 const char *buf, size_t count)
725{
726 unsigned deadline;
727
Mike Snitzere83068a2016-05-24 21:16:51 -0400728 if (dm_get_md_type(md) != DM_TYPE_REQUEST_BASED)
Mike Snitzer4cc96132016-05-12 16:28:10 -0400729 return count;
730
731 if (kstrtouint(buf, 10, &deadline))
732 return -EINVAL;
733
734 if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS)
735 deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS;
736
737 md->seq_rq_merge_deadline_usecs = deadline;
738
739 return count;
740}
741
742static bool dm_old_request_peeked_before_merge_deadline(struct mapped_device *md)
743{
744 ktime_t kt_deadline;
745
746 if (!md->seq_rq_merge_deadline_usecs)
747 return false;
748
749 kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC);
750 kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline);
751
752 return !ktime_after(ktime_get(), kt_deadline);
753}
754
755/*
756 * q->request_fn for old request-based dm.
757 * Called with the queue lock held.
758 */
759static void dm_old_request_fn(struct request_queue *q)
760{
761 struct mapped_device *md = q->queuedata;
762 struct dm_target *ti = md->immutable_target;
763 struct request *rq;
764 struct dm_rq_target_io *tio;
765 sector_t pos = 0;
766
767 if (unlikely(!ti)) {
768 int srcu_idx;
769 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
770
771 ti = dm_table_find_target(map, pos);
772 dm_put_live_table(md, srcu_idx);
773 }
774
775 /*
776 * For suspend, check blk_queue_stopped() and increment
777 * ->pending within a single queue_lock not to increment the
778 * number of in-flight I/Os after the queue is stopped in
779 * dm_suspend().
780 */
781 while (!blk_queue_stopped(q)) {
782 rq = blk_peek_request(q);
783 if (!rq)
784 return;
785
786 /* always use block 0 to find the target for flushes for now */
787 pos = 0;
788 if (req_op(rq) != REQ_OP_FLUSH)
789 pos = blk_rq_pos(rq);
790
791 if ((dm_old_request_peeked_before_merge_deadline(md) &&
792 md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 &&
793 md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) ||
794 (ti->type->busy && ti->type->busy(ti))) {
Tahsin Erdoganbd9f55e2016-07-15 06:27:08 -0700795 blk_delay_queue(q, 10);
Mike Snitzer4cc96132016-05-12 16:28:10 -0400796 return;
797 }
798
799 dm_start_request(md, rq);
800
801 tio = tio_from_request(rq);
802 /* Establish tio->ti before queuing work (map_tio_request) */
803 tio->ti = ti;
804 queue_kthread_work(&md->kworker, &tio->work);
805 BUG_ON(!irqs_disabled());
806 }
807}
808
809/*
810 * Fully initialize a .request_fn request-based queue.
811 */
812int dm_old_init_request_queue(struct mapped_device *md)
813{
814 /* Fully initialize the queue */
815 if (!blk_init_allocated_queue(md->queue, dm_old_request_fn, NULL))
816 return -EINVAL;
817
818 /* disable dm_old_request_fn's merge heuristic by default */
819 md->seq_rq_merge_deadline_usecs = 0;
820
821 dm_init_normal_md_queue(md);
822 blk_queue_softirq_done(md->queue, dm_softirq_done);
823 blk_queue_prep_rq(md->queue, dm_old_prep_fn);
824
825 /* Initialize the request-based DM worker thread */
826 init_kthread_worker(&md->kworker);
827 md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
828 "kdmwork-%s", dm_device_name(md));
Mike Snitzer7193a9d2016-07-06 09:06:37 -0400829 if (IS_ERR(md->kworker_task))
830 return PTR_ERR(md->kworker_task);
Mike Snitzer4cc96132016-05-12 16:28:10 -0400831
832 elv_register_queue(md->queue);
833
834 return 0;
835}
836
837static int dm_mq_init_request(void *data, struct request *rq,
838 unsigned int hctx_idx, unsigned int request_idx,
839 unsigned int numa_node)
840{
841 struct mapped_device *md = data;
842 struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
843
844 /*
845 * Must initialize md member of tio, otherwise it won't
846 * be available in dm_mq_queue_rq.
847 */
848 tio->md = md;
849
850 if (md->init_tio_pdu) {
851 /* target-specific per-io data is immediately after the tio */
852 tio->info.ptr = tio + 1;
853 }
854
855 return 0;
856}
857
858static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
859 const struct blk_mq_queue_data *bd)
860{
861 struct request *rq = bd->rq;
862 struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
863 struct mapped_device *md = tio->md;
864 struct dm_target *ti = md->immutable_target;
865
866 if (unlikely(!ti)) {
867 int srcu_idx;
868 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
869
870 ti = dm_table_find_target(map, 0);
871 dm_put_live_table(md, srcu_idx);
872 }
873
Mike Snitzer7d9595d2016-08-02 12:51:11 -0400874 /*
875 * On suspend dm_stop_queue() handles stopping the blk-mq
876 * request_queue BUT: even though the hw_queues are marked
877 * BLK_MQ_S_STOPPED at that point there is still a race that
878 * is allowing block/blk-mq.c to call ->queue_rq against a
879 * hctx that it really shouldn't. The following check guards
880 * against this rarity (albeit _not_ race-free).
881 */
882 if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
883 return BLK_MQ_RQ_QUEUE_BUSY;
884
Mike Snitzer4cc96132016-05-12 16:28:10 -0400885 if (ti->type->busy && ti->type->busy(ti))
886 return BLK_MQ_RQ_QUEUE_BUSY;
887
888 dm_start_request(md, rq);
889
890 /* Init tio using md established in .init_request */
891 init_tio(tio, rq, md);
892
893 /*
894 * Establish tio->ti before calling map_request().
895 */
896 tio->ti = ti;
897
898 /* Direct call is fine since .queue_rq allows allocations */
899 if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) {
900 /* Undo dm_start_request() before requeuing */
901 rq_end_stats(md, rq);
902 rq_completed(md, rq_data_dir(rq), false);
903 return BLK_MQ_RQ_QUEUE_BUSY;
904 }
905
906 return BLK_MQ_RQ_QUEUE_OK;
907}
908
909static struct blk_mq_ops dm_mq_ops = {
910 .queue_rq = dm_mq_queue_rq,
911 .map_queue = blk_mq_map_queue,
912 .complete = dm_softirq_done,
913 .init_request = dm_mq_init_request,
914};
915
Mike Snitzere83068a2016-05-24 21:16:51 -0400916int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
Mike Snitzer4cc96132016-05-12 16:28:10 -0400917{
918 struct request_queue *q;
Mike Snitzere83068a2016-05-24 21:16:51 -0400919 struct dm_target *immutable_tgt;
Mike Snitzer4cc96132016-05-12 16:28:10 -0400920 int err;
921
Mike Snitzere83068a2016-05-24 21:16:51 -0400922 if (!dm_table_all_blk_mq_devices(t)) {
Mike Snitzer4cc96132016-05-12 16:28:10 -0400923 DMERR("request-based dm-mq may only be stacked on blk-mq device(s)");
924 return -EINVAL;
925 }
926
927 md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
928 if (!md->tag_set)
929 return -ENOMEM;
930
931 md->tag_set->ops = &dm_mq_ops;
932 md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
933 md->tag_set->numa_node = md->numa_node_id;
934 md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
935 md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
936 md->tag_set->driver_data = md;
937
938 md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
Mike Snitzere83068a2016-05-24 21:16:51 -0400939 immutable_tgt = dm_table_get_immutable_target(t);
Mike Snitzer4cc96132016-05-12 16:28:10 -0400940 if (immutable_tgt && immutable_tgt->per_io_data_size) {
941 /* any target-specific per-io data is immediately after the tio */
942 md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
943 md->init_tio_pdu = true;
944 }
945
946 err = blk_mq_alloc_tag_set(md->tag_set);
947 if (err)
948 goto out_kfree_tag_set;
949
950 q = blk_mq_init_allocated_queue(md->tag_set, md->queue);
951 if (IS_ERR(q)) {
952 err = PTR_ERR(q);
953 goto out_tag_set;
954 }
955 dm_init_md_queue(md);
956
957 /* backfill 'mq' sysfs registration normally done in blk_register_queue */
958 blk_mq_register_disk(md->disk);
959
960 return 0;
961
962out_tag_set:
963 blk_mq_free_tag_set(md->tag_set);
964out_kfree_tag_set:
965 kfree(md->tag_set);
966
967 return err;
968}
969
970void dm_mq_cleanup_mapped_device(struct mapped_device *md)
971{
972 if (md->tag_set) {
973 blk_mq_free_tag_set(md->tag_set);
974 kfree(md->tag_set);
975 }
976}
977
978module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
979MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
980
981module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
982MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
983
984module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR);
985MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices");
986
987module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR);
988MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");