1 // SPDX-License-Identifier: GPL-2.0
3 * Block multiqueue core code
5 * Copyright (C) 2013-2014 Jens Axboe
6 * Copyright (C) 2013-2014 Christoph Hellwig
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/backing-dev.h>
11 #include <linux/bio.h>
12 #include <linux/blkdev.h>
13 #include <linux/blk-integrity.h>
14 #include <linux/kmemleak.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/workqueue.h>
19 #include <linux/smp.h>
20 #include <linux/interrupt.h>
21 #include <linux/llist.h>
22 #include <linux/cpu.h>
23 #include <linux/cache.h>
24 #include <linux/sched/sysctl.h>
25 #include <linux/sched/topology.h>
26 #include <linux/sched/signal.h>
27 #include <linux/delay.h>
28 #include <linux/crash_dump.h>
29 #include <linux/prefetch.h>
30 #include <linux/blk-crypto.h>
31 #include <linux/part_stat.h>
33 #include <trace/events/block.h>
35 #include <linux/t10-pi.h>
38 #include "blk-mq-debugfs.h"
41 #include "blk-mq-sched.h"
42 #include "blk-rq-qos.h"
43 #include "blk-ioprio.h"
45 static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
46 static DEFINE_PER_CPU(call_single_data_t, blk_cpu_csd);
48 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags);
49 static void blk_mq_request_bypass_insert(struct request *rq,
51 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
52 struct list_head *list);
53 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
54 struct io_comp_batch *iob, unsigned int flags);
57 * Check if any of the ctx, dispatch list or elevator
58 * have pending work in this hardware queue.
60 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
62 return !list_empty_careful(&hctx->dispatch) ||
63 sbitmap_any_bit_set(&hctx->ctx_map) ||
64 blk_mq_sched_has_work(hctx);
68 * Mark this ctx as having pending work in this hardware queue
70 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
71 struct blk_mq_ctx *ctx)
73 const int bit = ctx->index_hw[hctx->type];
75 if (!sbitmap_test_bit(&hctx->ctx_map, bit))
76 sbitmap_set_bit(&hctx->ctx_map, bit);
79 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
80 struct blk_mq_ctx *ctx)
82 const int bit = ctx->index_hw[hctx->type];
84 sbitmap_clear_bit(&hctx->ctx_map, bit);
88 struct block_device *part;
89 unsigned int inflight[2];
92 static bool blk_mq_check_inflight(struct request *rq, void *priv)
94 struct mq_inflight *mi = priv;
96 if (rq->part && blk_do_io_stat(rq) &&
97 (!mi->part->bd_partno || rq->part == mi->part) &&
98 blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
99 mi->inflight[rq_data_dir(rq)]++;
104 unsigned int blk_mq_in_flight(struct request_queue *q,
105 struct block_device *part)
107 struct mq_inflight mi = { .part = part };
109 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
111 return mi.inflight[0] + mi.inflight[1];
114 void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
115 unsigned int inflight[2])
117 struct mq_inflight mi = { .part = part };
119 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
120 inflight[0] = mi.inflight[0];
121 inflight[1] = mi.inflight[1];
124 void blk_freeze_queue_start(struct request_queue *q)
126 mutex_lock(&q->mq_freeze_lock);
127 if (++q->mq_freeze_depth == 1) {
128 percpu_ref_kill(&q->q_usage_counter);
129 mutex_unlock(&q->mq_freeze_lock);
131 blk_mq_run_hw_queues(q, false);
133 mutex_unlock(&q->mq_freeze_lock);
136 EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
138 void blk_mq_freeze_queue_wait(struct request_queue *q)
140 wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
142 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
144 int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
145 unsigned long timeout)
147 return wait_event_timeout(q->mq_freeze_wq,
148 percpu_ref_is_zero(&q->q_usage_counter),
151 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
154 * Guarantee no request is in use, so we can change any data structure of
155 * the queue afterward.
157 void blk_freeze_queue(struct request_queue *q)
160 * In the !blk_mq case we are only calling this to kill the
161 * q_usage_counter, otherwise this increases the freeze depth
162 * and waits for it to return to zero. For this reason there is
163 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
164 * exported to drivers as the only user for unfreeze is blk_mq.
166 blk_freeze_queue_start(q);
167 blk_mq_freeze_queue_wait(q);
170 void blk_mq_freeze_queue(struct request_queue *q)
173 * ...just an alias to keep freeze and unfreeze actions balanced
174 * in the blk_mq_* namespace
178 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
180 void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
182 mutex_lock(&q->mq_freeze_lock);
184 q->q_usage_counter.data->force_atomic = true;
185 q->mq_freeze_depth--;
186 WARN_ON_ONCE(q->mq_freeze_depth < 0);
187 if (!q->mq_freeze_depth) {
188 percpu_ref_resurrect(&q->q_usage_counter);
189 wake_up_all(&q->mq_freeze_wq);
191 mutex_unlock(&q->mq_freeze_lock);
194 void blk_mq_unfreeze_queue(struct request_queue *q)
196 __blk_mq_unfreeze_queue(q, false);
198 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
201 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
202 * mpt3sas driver such that this function can be removed.
204 void blk_mq_quiesce_queue_nowait(struct request_queue *q)
208 spin_lock_irqsave(&q->queue_lock, flags);
209 if (!q->quiesce_depth++)
210 blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
211 spin_unlock_irqrestore(&q->queue_lock, flags);
213 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
216 * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
217 * @set: tag_set to wait on
219 * Note: it is driver's responsibility for making sure that quiesce has
220 * been started on or more of the request_queues of the tag_set. This
221 * function only waits for the quiesce on those request_queues that had
222 * the quiesce flag set using blk_mq_quiesce_queue_nowait.
224 void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set)
226 if (set->flags & BLK_MQ_F_BLOCKING)
227 synchronize_srcu(set->srcu);
231 EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
234 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
237 * Note: this function does not prevent that the struct request end_io()
238 * callback function is invoked. Once this function is returned, we make
239 * sure no dispatch can happen until the queue is unquiesced via
240 * blk_mq_unquiesce_queue().
242 void blk_mq_quiesce_queue(struct request_queue *q)
244 blk_mq_quiesce_queue_nowait(q);
245 /* nothing to wait for non-mq queues */
247 blk_mq_wait_quiesce_done(q->tag_set);
249 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
252 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
255 * This function recovers queue into the state before quiescing
256 * which is done by blk_mq_quiesce_queue.
258 void blk_mq_unquiesce_queue(struct request_queue *q)
261 bool run_queue = false;
263 spin_lock_irqsave(&q->queue_lock, flags);
264 if (WARN_ON_ONCE(q->quiesce_depth <= 0)) {
266 } else if (!--q->quiesce_depth) {
267 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
270 spin_unlock_irqrestore(&q->queue_lock, flags);
272 /* dispatch requests which are inserted during quiescing */
274 blk_mq_run_hw_queues(q, true);
276 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
278 void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set)
280 struct request_queue *q;
282 mutex_lock(&set->tag_list_lock);
283 list_for_each_entry(q, &set->tag_list, tag_set_list) {
284 if (!blk_queue_skip_tagset_quiesce(q))
285 blk_mq_quiesce_queue_nowait(q);
287 blk_mq_wait_quiesce_done(set);
288 mutex_unlock(&set->tag_list_lock);
290 EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);
292 void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set)
294 struct request_queue *q;
296 mutex_lock(&set->tag_list_lock);
297 list_for_each_entry(q, &set->tag_list, tag_set_list) {
298 if (!blk_queue_skip_tagset_quiesce(q))
299 blk_mq_unquiesce_queue(q);
301 mutex_unlock(&set->tag_list_lock);
303 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset);
305 void blk_mq_wake_waiters(struct request_queue *q)
307 struct blk_mq_hw_ctx *hctx;
310 queue_for_each_hw_ctx(q, hctx, i)
311 if (blk_mq_hw_queue_mapped(hctx))
312 blk_mq_tag_wakeup_all(hctx->tags, true);
315 void blk_rq_init(struct request_queue *q, struct request *rq)
317 memset(rq, 0, sizeof(*rq));
319 INIT_LIST_HEAD(&rq->queuelist);
321 rq->__sector = (sector_t) -1;
322 INIT_HLIST_NODE(&rq->hash);
323 RB_CLEAR_NODE(&rq->rb_node);
324 rq->tag = BLK_MQ_NO_TAG;
325 rq->internal_tag = BLK_MQ_NO_TAG;
326 rq->start_time_ns = ktime_get_ns();
328 blk_crypto_rq_set_defaults(rq);
330 EXPORT_SYMBOL(blk_rq_init);
332 /* Set start and alloc time when the allocated request is actually used */
333 static inline void blk_mq_rq_time_init(struct request *rq, u64 alloc_time_ns)
335 if (blk_mq_need_time_stamp(rq))
336 rq->start_time_ns = ktime_get_ns();
338 rq->start_time_ns = 0;
340 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
341 if (blk_queue_rq_alloc_time(rq->q))
342 rq->alloc_time_ns = alloc_time_ns ?: rq->start_time_ns;
344 rq->alloc_time_ns = 0;
348 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
349 struct blk_mq_tags *tags, unsigned int tag)
351 struct blk_mq_ctx *ctx = data->ctx;
352 struct blk_mq_hw_ctx *hctx = data->hctx;
353 struct request_queue *q = data->q;
354 struct request *rq = tags->static_rqs[tag];
359 rq->cmd_flags = data->cmd_flags;
361 if (data->flags & BLK_MQ_REQ_PM)
362 data->rq_flags |= RQF_PM;
363 if (blk_queue_io_stat(q))
364 data->rq_flags |= RQF_IO_STAT;
365 rq->rq_flags = data->rq_flags;
367 if (data->rq_flags & RQF_SCHED_TAGS) {
368 rq->tag = BLK_MQ_NO_TAG;
369 rq->internal_tag = tag;
372 rq->internal_tag = BLK_MQ_NO_TAG;
377 rq->io_start_time_ns = 0;
378 rq->stats_sectors = 0;
379 rq->nr_phys_segments = 0;
380 #if defined(CONFIG_BLK_DEV_INTEGRITY)
381 rq->nr_integrity_segments = 0;
384 rq->end_io_data = NULL;
386 blk_crypto_rq_set_defaults(rq);
387 INIT_LIST_HEAD(&rq->queuelist);
388 /* tag was already set */
389 WRITE_ONCE(rq->deadline, 0);
392 if (rq->rq_flags & RQF_USE_SCHED) {
393 struct elevator_queue *e = data->q->elevator;
395 INIT_HLIST_NODE(&rq->hash);
396 RB_CLEAR_NODE(&rq->rb_node);
398 if (e->type->ops.prepare_request)
399 e->type->ops.prepare_request(rq);
405 static inline struct request *
406 __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data)
408 unsigned int tag, tag_offset;
409 struct blk_mq_tags *tags;
411 unsigned long tag_mask;
414 tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset);
415 if (unlikely(!tag_mask))
418 tags = blk_mq_tags_from_data(data);
419 for (i = 0; tag_mask; i++) {
420 if (!(tag_mask & (1UL << i)))
422 tag = tag_offset + i;
423 prefetch(tags->static_rqs[tag]);
424 tag_mask &= ~(1UL << i);
425 rq = blk_mq_rq_ctx_init(data, tags, tag);
426 rq_list_add(data->cached_rq, rq);
429 if (!(data->rq_flags & RQF_SCHED_TAGS))
430 blk_mq_add_active_requests(data->hctx, nr);
431 /* caller already holds a reference, add for remainder */
432 percpu_ref_get_many(&data->q->q_usage_counter, nr - 1);
435 return rq_list_pop(data->cached_rq);
438 static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
440 struct request_queue *q = data->q;
441 u64 alloc_time_ns = 0;
445 /* alloc_time includes depth and tag waits */
446 if (blk_queue_rq_alloc_time(q))
447 alloc_time_ns = ktime_get_ns();
449 if (data->cmd_flags & REQ_NOWAIT)
450 data->flags |= BLK_MQ_REQ_NOWAIT;
454 * All requests use scheduler tags when an I/O scheduler is
455 * enabled for the queue.
457 data->rq_flags |= RQF_SCHED_TAGS;
460 * Flush/passthrough requests are special and go directly to the
463 if ((data->cmd_flags & REQ_OP_MASK) != REQ_OP_FLUSH &&
464 !blk_op_is_passthrough(data->cmd_flags)) {
465 struct elevator_mq_ops *ops = &q->elevator->type->ops;
467 WARN_ON_ONCE(data->flags & BLK_MQ_REQ_RESERVED);
469 data->rq_flags |= RQF_USE_SCHED;
470 if (ops->limit_depth)
471 ops->limit_depth(data->cmd_flags, data);
476 data->ctx = blk_mq_get_ctx(q);
477 data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx);
478 if (!(data->rq_flags & RQF_SCHED_TAGS))
479 blk_mq_tag_busy(data->hctx);
481 if (data->flags & BLK_MQ_REQ_RESERVED)
482 data->rq_flags |= RQF_RESV;
485 * Try batched alloc if we want more than 1 tag.
487 if (data->nr_tags > 1) {
488 rq = __blk_mq_alloc_requests_batch(data);
490 blk_mq_rq_time_init(rq, alloc_time_ns);
497 * Waiting allocations only fail because of an inactive hctx. In that
498 * case just retry the hctx assignment and tag allocation as CPU hotplug
499 * should have migrated us to an online CPU by now.
501 tag = blk_mq_get_tag(data);
502 if (tag == BLK_MQ_NO_TAG) {
503 if (data->flags & BLK_MQ_REQ_NOWAIT)
506 * Give up the CPU and sleep for a random short time to
507 * ensure that thread using a realtime scheduling class
508 * are migrated off the CPU, and thus off the hctx that
515 if (!(data->rq_flags & RQF_SCHED_TAGS))
516 blk_mq_inc_active_requests(data->hctx);
517 rq = blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag);
518 blk_mq_rq_time_init(rq, alloc_time_ns);
522 static struct request *blk_mq_rq_cache_fill(struct request_queue *q,
523 struct blk_plug *plug,
525 blk_mq_req_flags_t flags)
527 struct blk_mq_alloc_data data = {
531 .nr_tags = plug->nr_ios,
532 .cached_rq = &plug->cached_rq,
536 if (blk_queue_enter(q, flags))
541 rq = __blk_mq_alloc_requests(&data);
547 static struct request *blk_mq_alloc_cached_request(struct request_queue *q,
549 blk_mq_req_flags_t flags)
551 struct blk_plug *plug = current->plug;
557 if (rq_list_empty(plug->cached_rq)) {
558 if (plug->nr_ios == 1)
560 rq = blk_mq_rq_cache_fill(q, plug, opf, flags);
564 rq = rq_list_peek(&plug->cached_rq);
565 if (!rq || rq->q != q)
568 if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type)
570 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf))
573 plug->cached_rq = rq_list_next(rq);
574 blk_mq_rq_time_init(rq, 0);
578 INIT_LIST_HEAD(&rq->queuelist);
582 struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf,
583 blk_mq_req_flags_t flags)
587 rq = blk_mq_alloc_cached_request(q, opf, flags);
589 struct blk_mq_alloc_data data = {
597 ret = blk_queue_enter(q, flags);
601 rq = __blk_mq_alloc_requests(&data);
606 rq->__sector = (sector_t) -1;
607 rq->bio = rq->biotail = NULL;
611 return ERR_PTR(-EWOULDBLOCK);
613 EXPORT_SYMBOL(blk_mq_alloc_request);
615 struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
616 blk_opf_t opf, blk_mq_req_flags_t flags, unsigned int hctx_idx)
618 struct blk_mq_alloc_data data = {
624 u64 alloc_time_ns = 0;
630 /* alloc_time includes depth and tag waits */
631 if (blk_queue_rq_alloc_time(q))
632 alloc_time_ns = ktime_get_ns();
635 * If the tag allocator sleeps we could get an allocation for a
636 * different hardware context. No need to complicate the low level
637 * allocator for this for the rare use case of a command tied to
640 if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)) ||
641 WARN_ON_ONCE(!(flags & BLK_MQ_REQ_RESERVED)))
642 return ERR_PTR(-EINVAL);
644 if (hctx_idx >= q->nr_hw_queues)
645 return ERR_PTR(-EIO);
647 ret = blk_queue_enter(q, flags);
652 * Check if the hardware context is actually mapped to anything.
653 * If not tell the caller that it should skip this queue.
656 data.hctx = xa_load(&q->hctx_table, hctx_idx);
657 if (!blk_mq_hw_queue_mapped(data.hctx))
659 cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
660 if (cpu >= nr_cpu_ids)
662 data.ctx = __blk_mq_get_ctx(q, cpu);
665 data.rq_flags |= RQF_SCHED_TAGS;
667 blk_mq_tag_busy(data.hctx);
669 if (flags & BLK_MQ_REQ_RESERVED)
670 data.rq_flags |= RQF_RESV;
673 tag = blk_mq_get_tag(&data);
674 if (tag == BLK_MQ_NO_TAG)
676 if (!(data.rq_flags & RQF_SCHED_TAGS))
677 blk_mq_inc_active_requests(data.hctx);
678 rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag);
679 blk_mq_rq_time_init(rq, alloc_time_ns);
681 rq->__sector = (sector_t) -1;
682 rq->bio = rq->biotail = NULL;
689 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
691 static void blk_mq_finish_request(struct request *rq)
693 struct request_queue *q = rq->q;
695 if (rq->rq_flags & RQF_USE_SCHED) {
696 q->elevator->type->ops.finish_request(rq);
698 * For postflush request that may need to be
699 * completed twice, we should clear this flag
700 * to avoid double finish_request() on the rq.
702 rq->rq_flags &= ~RQF_USE_SCHED;
706 static void __blk_mq_free_request(struct request *rq)
708 struct request_queue *q = rq->q;
709 struct blk_mq_ctx *ctx = rq->mq_ctx;
710 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
711 const int sched_tag = rq->internal_tag;
713 blk_crypto_free_request(rq);
714 blk_pm_mark_last_busy(rq);
717 if (rq->tag != BLK_MQ_NO_TAG) {
718 blk_mq_dec_active_requests(hctx);
719 blk_mq_put_tag(hctx->tags, ctx, rq->tag);
721 if (sched_tag != BLK_MQ_NO_TAG)
722 blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
723 blk_mq_sched_restart(hctx);
727 void blk_mq_free_request(struct request *rq)
729 struct request_queue *q = rq->q;
731 blk_mq_finish_request(rq);
733 if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
734 laptop_io_completion(q->disk->bdi);
738 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
739 if (req_ref_put_and_test(rq))
740 __blk_mq_free_request(rq);
742 EXPORT_SYMBOL_GPL(blk_mq_free_request);
744 void blk_mq_free_plug_rqs(struct blk_plug *plug)
748 while ((rq = rq_list_pop(&plug->cached_rq)) != NULL)
749 blk_mq_free_request(rq);
752 void blk_dump_rq_flags(struct request *rq, char *msg)
754 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
755 rq->q->disk ? rq->q->disk->disk_name : "?",
756 (__force unsigned long long) rq->cmd_flags);
758 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
759 (unsigned long long)blk_rq_pos(rq),
760 blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
761 printk(KERN_INFO " bio %p, biotail %p, len %u\n",
762 rq->bio, rq->biotail, blk_rq_bytes(rq));
764 EXPORT_SYMBOL(blk_dump_rq_flags);
766 static void req_bio_endio(struct request *rq, struct bio *bio,
767 unsigned int nbytes, blk_status_t error)
769 if (unlikely(error)) {
770 bio->bi_status = error;
771 } else if (req_op(rq) == REQ_OP_ZONE_APPEND) {
773 * Partial zone append completions cannot be supported as the
774 * BIO fragments may end up not being written sequentially.
776 if (bio->bi_iter.bi_size != nbytes)
777 bio->bi_status = BLK_STS_IOERR;
779 bio->bi_iter.bi_sector = rq->__sector;
782 bio_advance(bio, nbytes);
784 if (unlikely(rq->rq_flags & RQF_QUIET))
785 bio_set_flag(bio, BIO_QUIET);
786 /* don't actually finish bio if it's part of flush sequence */
787 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
791 static void blk_account_io_completion(struct request *req, unsigned int bytes)
793 if (req->part && blk_do_io_stat(req)) {
794 const int sgrp = op_stat_group(req_op(req));
797 part_stat_add(req->part, sectors[sgrp], bytes >> 9);
802 static void blk_print_req_error(struct request *req, blk_status_t status)
804 printk_ratelimited(KERN_ERR
805 "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
806 "phys_seg %u prio class %u\n",
807 blk_status_to_str(status),
808 req->q->disk ? req->q->disk->disk_name : "?",
809 blk_rq_pos(req), (__force u32)req_op(req),
810 blk_op_str(req_op(req)),
811 (__force u32)(req->cmd_flags & ~REQ_OP_MASK),
812 req->nr_phys_segments,
813 IOPRIO_PRIO_CLASS(req->ioprio));
817 * Fully end IO on a request. Does not support partial completions, or
820 static void blk_complete_request(struct request *req)
822 const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0;
823 int total_bytes = blk_rq_bytes(req);
824 struct bio *bio = req->bio;
826 trace_block_rq_complete(req, BLK_STS_OK, total_bytes);
831 #ifdef CONFIG_BLK_DEV_INTEGRITY
832 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ)
833 req->q->integrity.profile->complete_fn(req, total_bytes);
837 * Upper layers may call blk_crypto_evict_key() anytime after the last
838 * bio_endio(). Therefore, the keyslot must be released before that.
840 blk_crypto_rq_put_keyslot(req);
842 blk_account_io_completion(req, total_bytes);
845 struct bio *next = bio->bi_next;
847 /* Completion has already been traced */
848 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
850 if (req_op(req) == REQ_OP_ZONE_APPEND)
851 bio->bi_iter.bi_sector = req->__sector;
859 * Reset counters so that the request stacking driver
860 * can find how many bytes remain in the request
870 * blk_update_request - Complete multiple bytes without completing the request
871 * @req: the request being processed
872 * @error: block status code
873 * @nr_bytes: number of bytes to complete for @req
876 * Ends I/O on a number of bytes attached to @req, but doesn't complete
877 * the request structure even if @req doesn't have leftover.
878 * If @req has leftover, sets it up for the next range of segments.
880 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
881 * %false return from this function.
884 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
885 * except in the consistency check at the end of this function.
888 * %false - this request doesn't have any more data
889 * %true - this request has more data
891 bool blk_update_request(struct request *req, blk_status_t error,
892 unsigned int nr_bytes)
896 trace_block_rq_complete(req, error, nr_bytes);
901 #ifdef CONFIG_BLK_DEV_INTEGRITY
902 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
904 req->q->integrity.profile->complete_fn(req, nr_bytes);
908 * Upper layers may call blk_crypto_evict_key() anytime after the last
909 * bio_endio(). Therefore, the keyslot must be released before that.
911 if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req))
912 __blk_crypto_rq_put_keyslot(req);
914 if (unlikely(error && !blk_rq_is_passthrough(req) &&
915 !(req->rq_flags & RQF_QUIET)) &&
916 !test_bit(GD_DEAD, &req->q->disk->state)) {
917 blk_print_req_error(req, error);
918 trace_block_rq_error(req, error, nr_bytes);
921 blk_account_io_completion(req, nr_bytes);
925 struct bio *bio = req->bio;
926 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
928 if (bio_bytes == bio->bi_iter.bi_size)
929 req->bio = bio->bi_next;
931 /* Completion has already been traced */
932 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
933 req_bio_endio(req, bio, bio_bytes, error);
935 total_bytes += bio_bytes;
936 nr_bytes -= bio_bytes;
947 * Reset counters so that the request stacking driver
948 * can find how many bytes remain in the request
955 req->__data_len -= total_bytes;
957 /* update sector only for requests with clear definition of sector */
958 if (!blk_rq_is_passthrough(req))
959 req->__sector += total_bytes >> 9;
961 /* mixed attributes always follow the first bio */
962 if (req->rq_flags & RQF_MIXED_MERGE) {
963 req->cmd_flags &= ~REQ_FAILFAST_MASK;
964 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
967 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
969 * If total number of sectors is less than the first segment
970 * size, something has gone terribly wrong.
972 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
973 blk_dump_rq_flags(req, "request botched");
974 req->__data_len = blk_rq_cur_bytes(req);
977 /* recalculate the number of segments */
978 req->nr_phys_segments = blk_recalc_rq_segments(req);
983 EXPORT_SYMBOL_GPL(blk_update_request);
985 static inline void blk_account_io_done(struct request *req, u64 now)
987 trace_block_io_done(req);
990 * Account IO completion. flush_rq isn't accounted as a
991 * normal IO on queueing nor completion. Accounting the
992 * containing request is enough.
994 if (blk_do_io_stat(req) && req->part &&
995 !(req->rq_flags & RQF_FLUSH_SEQ)) {
996 const int sgrp = op_stat_group(req_op(req));
999 update_io_ticks(req->part, jiffies, true);
1000 part_stat_inc(req->part, ios[sgrp]);
1001 part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
1006 static inline void blk_account_io_start(struct request *req)
1008 trace_block_io_start(req);
1010 if (blk_do_io_stat(req)) {
1012 * All non-passthrough requests are created from a bio with one
1013 * exception: when a flush command that is part of a flush sequence
1014 * generated by the state machine in blk-flush.c is cloned onto the
1015 * lower device by dm-multipath we can get here without a bio.
1018 req->part = req->bio->bi_bdev;
1020 req->part = req->q->disk->part0;
1023 update_io_ticks(req->part, jiffies, false);
1028 static inline void __blk_mq_end_request_acct(struct request *rq, u64 now)
1030 if (rq->rq_flags & RQF_STATS)
1031 blk_stat_add(rq, now);
1033 blk_mq_sched_completed_request(rq, now);
1034 blk_account_io_done(rq, now);
1037 inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
1039 if (blk_mq_need_time_stamp(rq))
1040 __blk_mq_end_request_acct(rq, ktime_get_ns());
1042 blk_mq_finish_request(rq);
1045 rq_qos_done(rq->q, rq);
1046 if (rq->end_io(rq, error) == RQ_END_IO_FREE)
1047 blk_mq_free_request(rq);
1049 blk_mq_free_request(rq);
1052 EXPORT_SYMBOL(__blk_mq_end_request);
1054 void blk_mq_end_request(struct request *rq, blk_status_t error)
1056 if (blk_update_request(rq, error, blk_rq_bytes(rq)))
1058 __blk_mq_end_request(rq, error);
1060 EXPORT_SYMBOL(blk_mq_end_request);
1062 #define TAG_COMP_BATCH 32
1064 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
1065 int *tag_array, int nr_tags)
1067 struct request_queue *q = hctx->queue;
1069 blk_mq_sub_active_requests(hctx, nr_tags);
1071 blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
1072 percpu_ref_put_many(&q->q_usage_counter, nr_tags);
1075 void blk_mq_end_request_batch(struct io_comp_batch *iob)
1077 int tags[TAG_COMP_BATCH], nr_tags = 0;
1078 struct blk_mq_hw_ctx *cur_hctx = NULL;
1083 now = ktime_get_ns();
1085 while ((rq = rq_list_pop(&iob->req_list)) != NULL) {
1087 prefetch(rq->rq_next);
1089 blk_complete_request(rq);
1091 __blk_mq_end_request_acct(rq, now);
1093 blk_mq_finish_request(rq);
1095 rq_qos_done(rq->q, rq);
1098 * If end_io handler returns NONE, then it still has
1099 * ownership of the request.
1101 if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
1104 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1105 if (!req_ref_put_and_test(rq))
1108 blk_crypto_free_request(rq);
1109 blk_pm_mark_last_busy(rq);
1111 if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) {
1113 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1115 cur_hctx = rq->mq_hctx;
1117 tags[nr_tags++] = rq->tag;
1121 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1123 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch);
1125 static void blk_complete_reqs(struct llist_head *list)
1127 struct llist_node *entry = llist_reverse_order(llist_del_all(list));
1128 struct request *rq, *next;
1130 llist_for_each_entry_safe(rq, next, entry, ipi_list)
1131 rq->q->mq_ops->complete(rq);
1134 static __latent_entropy void blk_done_softirq(struct softirq_action *h)
1136 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
1139 static int blk_softirq_cpu_dead(unsigned int cpu)
1141 blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
1145 static void __blk_mq_complete_request_remote(void *data)
1147 __raise_softirq_irqoff(BLOCK_SOFTIRQ);
1150 static inline bool blk_mq_complete_need_ipi(struct request *rq)
1152 int cpu = raw_smp_processor_id();
1154 if (!IS_ENABLED(CONFIG_SMP) ||
1155 !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
1158 * With force threaded interrupts enabled, raising softirq from an SMP
1159 * function call will always result in waking the ksoftirqd thread.
1160 * This is probably worse than completing the request on a different
1163 if (force_irqthreads())
1166 /* same CPU or cache domain? Complete locally */
1167 if (cpu == rq->mq_ctx->cpu ||
1168 (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
1169 cpus_share_cache(cpu, rq->mq_ctx->cpu)))
1172 /* don't try to IPI to an offline CPU */
1173 return cpu_online(rq->mq_ctx->cpu);
1176 static void blk_mq_complete_send_ipi(struct request *rq)
1180 cpu = rq->mq_ctx->cpu;
1181 if (llist_add(&rq->ipi_list, &per_cpu(blk_cpu_done, cpu)))
1182 smp_call_function_single_async(cpu, &per_cpu(blk_cpu_csd, cpu));
1185 static void blk_mq_raise_softirq(struct request *rq)
1187 struct llist_head *list;
1190 list = this_cpu_ptr(&blk_cpu_done);
1191 if (llist_add(&rq->ipi_list, list))
1192 raise_softirq(BLOCK_SOFTIRQ);
1196 bool blk_mq_complete_request_remote(struct request *rq)
1198 WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
1201 * For request which hctx has only one ctx mapping,
1202 * or a polled request, always complete locally,
1203 * it's pointless to redirect the completion.
1205 if ((rq->mq_hctx->nr_ctx == 1 &&
1206 rq->mq_ctx->cpu == raw_smp_processor_id()) ||
1207 rq->cmd_flags & REQ_POLLED)
1210 if (blk_mq_complete_need_ipi(rq)) {
1211 blk_mq_complete_send_ipi(rq);
1215 if (rq->q->nr_hw_queues == 1) {
1216 blk_mq_raise_softirq(rq);
1221 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
1224 * blk_mq_complete_request - end I/O on a request
1225 * @rq: the request being processed
1228 * Complete a request by scheduling the ->complete_rq operation.
1230 void blk_mq_complete_request(struct request *rq)
1232 if (!blk_mq_complete_request_remote(rq))
1233 rq->q->mq_ops->complete(rq);
1235 EXPORT_SYMBOL(blk_mq_complete_request);
1238 * blk_mq_start_request - Start processing a request
1239 * @rq: Pointer to request to be started
1241 * Function used by device drivers to notify the block layer that a request
1242 * is going to be processed now, so blk layer can do proper initializations
1243 * such as starting the timeout timer.
1245 void blk_mq_start_request(struct request *rq)
1247 struct request_queue *q = rq->q;
1249 trace_block_rq_issue(rq);
1251 if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
1252 rq->io_start_time_ns = ktime_get_ns();
1253 rq->stats_sectors = blk_rq_sectors(rq);
1254 rq->rq_flags |= RQF_STATS;
1255 rq_qos_issue(q, rq);
1258 WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
1261 WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
1262 rq->mq_hctx->tags->rqs[rq->tag] = rq;
1264 #ifdef CONFIG_BLK_DEV_INTEGRITY
1265 if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
1266 q->integrity.profile->prepare_fn(rq);
1268 if (rq->bio && rq->bio->bi_opf & REQ_POLLED)
1269 WRITE_ONCE(rq->bio->bi_cookie, rq->mq_hctx->queue_num);
1271 EXPORT_SYMBOL(blk_mq_start_request);
1274 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
1275 * queues. This is important for md arrays to benefit from merging
1278 static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
1280 if (plug->multiple_queues)
1281 return BLK_MAX_REQUEST_COUNT * 2;
1282 return BLK_MAX_REQUEST_COUNT;
1285 static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
1287 struct request *last = rq_list_peek(&plug->mq_list);
1289 if (!plug->rq_count) {
1290 trace_block_plug(rq->q);
1291 } else if (plug->rq_count >= blk_plug_max_rq_count(plug) ||
1292 (!blk_queue_nomerges(rq->q) &&
1293 blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
1294 blk_mq_flush_plug_list(plug, false);
1296 trace_block_plug(rq->q);
1299 if (!plug->multiple_queues && last && last->q != rq->q)
1300 plug->multiple_queues = true;
1302 * Any request allocated from sched tags can't be issued to
1303 * ->queue_rqs() directly
1305 if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS))
1306 plug->has_elevator = true;
1308 rq_list_add(&plug->mq_list, rq);
1313 * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
1314 * @rq: request to insert
1315 * @at_head: insert request at head or tail of queue
1318 * Insert a fully prepared request at the back of the I/O scheduler queue
1319 * for execution. Don't wait for completion.
1322 * This function will invoke @done directly if the queue is dead.
1324 void blk_execute_rq_nowait(struct request *rq, bool at_head)
1326 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1328 WARN_ON(irqs_disabled());
1329 WARN_ON(!blk_rq_is_passthrough(rq));
1331 blk_account_io_start(rq);
1334 * As plugging can be enabled for passthrough requests on a zoned
1335 * device, directly accessing the plug instead of using blk_mq_plug()
1336 * should not have any consequences.
1338 if (current->plug && !at_head) {
1339 blk_add_rq_to_plug(current->plug, rq);
1343 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1344 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
1346 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
1348 struct blk_rq_wait {
1349 struct completion done;
1353 static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret)
1355 struct blk_rq_wait *wait = rq->end_io_data;
1358 complete(&wait->done);
1359 return RQ_END_IO_NONE;
1362 bool blk_rq_is_poll(struct request *rq)
1366 if (rq->mq_hctx->type != HCTX_TYPE_POLL)
1370 EXPORT_SYMBOL_GPL(blk_rq_is_poll);
1372 static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
1375 blk_hctx_poll(rq->q, rq->mq_hctx, NULL, 0);
1377 } while (!completion_done(wait));
1381 * blk_execute_rq - insert a request into queue for execution
1382 * @rq: request to insert
1383 * @at_head: insert request at head or tail of queue
1386 * Insert a fully prepared request at the back of the I/O scheduler queue
1387 * for execution and wait for completion.
1388 * Return: The blk_status_t result provided to blk_mq_end_request().
1390 blk_status_t blk_execute_rq(struct request *rq, bool at_head)
1392 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1393 struct blk_rq_wait wait = {
1394 .done = COMPLETION_INITIALIZER_ONSTACK(wait.done),
1397 WARN_ON(irqs_disabled());
1398 WARN_ON(!blk_rq_is_passthrough(rq));
1400 rq->end_io_data = &wait;
1401 rq->end_io = blk_end_sync_rq;
1403 blk_account_io_start(rq);
1404 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1405 blk_mq_run_hw_queue(hctx, false);
1407 if (blk_rq_is_poll(rq)) {
1408 blk_rq_poll_completion(rq, &wait.done);
1411 * Prevent hang_check timer from firing at us during very long
1414 unsigned long hang_check = sysctl_hung_task_timeout_secs;
1417 while (!wait_for_completion_io_timeout(&wait.done,
1418 hang_check * (HZ/2)))
1421 wait_for_completion_io(&wait.done);
1426 EXPORT_SYMBOL(blk_execute_rq);
1428 static void __blk_mq_requeue_request(struct request *rq)
1430 struct request_queue *q = rq->q;
1432 blk_mq_put_driver_tag(rq);
1434 trace_block_rq_requeue(rq);
1435 rq_qos_requeue(q, rq);
1437 if (blk_mq_request_started(rq)) {
1438 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1439 rq->rq_flags &= ~RQF_TIMED_OUT;
1443 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
1445 struct request_queue *q = rq->q;
1446 unsigned long flags;
1448 __blk_mq_requeue_request(rq);
1450 /* this request will be re-inserted to io scheduler queue */
1451 blk_mq_sched_requeue_request(rq);
1453 spin_lock_irqsave(&q->requeue_lock, flags);
1454 list_add_tail(&rq->queuelist, &q->requeue_list);
1455 spin_unlock_irqrestore(&q->requeue_lock, flags);
1457 if (kick_requeue_list)
1458 blk_mq_kick_requeue_list(q);
1460 EXPORT_SYMBOL(blk_mq_requeue_request);
1462 static void blk_mq_requeue_work(struct work_struct *work)
1464 struct request_queue *q =
1465 container_of(work, struct request_queue, requeue_work.work);
1467 LIST_HEAD(flush_list);
1470 spin_lock_irq(&q->requeue_lock);
1471 list_splice_init(&q->requeue_list, &rq_list);
1472 list_splice_init(&q->flush_list, &flush_list);
1473 spin_unlock_irq(&q->requeue_lock);
1475 while (!list_empty(&rq_list)) {
1476 rq = list_entry(rq_list.next, struct request, queuelist);
1478 * If RQF_DONTPREP ist set, the request has been started by the
1479 * driver already and might have driver-specific data allocated
1480 * already. Insert it into the hctx dispatch list to avoid
1481 * block layer merges for the request.
1483 if (rq->rq_flags & RQF_DONTPREP) {
1484 list_del_init(&rq->queuelist);
1485 blk_mq_request_bypass_insert(rq, 0);
1487 list_del_init(&rq->queuelist);
1488 blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
1492 while (!list_empty(&flush_list)) {
1493 rq = list_entry(flush_list.next, struct request, queuelist);
1494 list_del_init(&rq->queuelist);
1495 blk_mq_insert_request(rq, 0);
1498 blk_mq_run_hw_queues(q, false);
1501 void blk_mq_kick_requeue_list(struct request_queue *q)
1503 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
1505 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
1507 void blk_mq_delay_kick_requeue_list(struct request_queue *q,
1508 unsigned long msecs)
1510 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
1511 msecs_to_jiffies(msecs));
1513 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
1515 static bool blk_is_flush_data_rq(struct request *rq)
1517 return (rq->rq_flags & RQF_FLUSH_SEQ) && !is_flush_rq(rq);
1520 static bool blk_mq_rq_inflight(struct request *rq, void *priv)
1523 * If we find a request that isn't idle we know the queue is busy
1524 * as it's checked in the iter.
1525 * Return false to stop the iteration.
1527 * In case of queue quiesce, if one flush data request is completed,
1528 * don't count it as inflight given the flush sequence is suspended,
1529 * and the original flush data request is invisible to driver, just
1530 * like other pending requests because of quiesce
1532 if (blk_mq_request_started(rq) && !(blk_queue_quiesced(rq->q) &&
1533 blk_is_flush_data_rq(rq) &&
1534 blk_mq_request_completed(rq))) {
1544 bool blk_mq_queue_inflight(struct request_queue *q)
1548 blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
1551 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
1553 static void blk_mq_rq_timed_out(struct request *req)
1555 req->rq_flags |= RQF_TIMED_OUT;
1556 if (req->q->mq_ops->timeout) {
1557 enum blk_eh_timer_return ret;
1559 ret = req->q->mq_ops->timeout(req);
1560 if (ret == BLK_EH_DONE)
1562 WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
1568 struct blk_expired_data {
1569 bool has_timedout_rq;
1571 unsigned long timeout_start;
1574 static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired)
1576 unsigned long deadline;
1578 if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
1580 if (rq->rq_flags & RQF_TIMED_OUT)
1583 deadline = READ_ONCE(rq->deadline);
1584 if (time_after_eq(expired->timeout_start, deadline))
1587 if (expired->next == 0)
1588 expired->next = deadline;
1589 else if (time_after(expired->next, deadline))
1590 expired->next = deadline;
1594 void blk_mq_put_rq_ref(struct request *rq)
1596 if (is_flush_rq(rq)) {
1597 if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
1598 blk_mq_free_request(rq);
1599 } else if (req_ref_put_and_test(rq)) {
1600 __blk_mq_free_request(rq);
1604 static bool blk_mq_check_expired(struct request *rq, void *priv)
1606 struct blk_expired_data *expired = priv;
1609 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1610 * be reallocated underneath the timeout handler's processing, then
1611 * the expire check is reliable. If the request is not expired, then
1612 * it was completed and reallocated as a new request after returning
1613 * from blk_mq_check_expired().
1615 if (blk_mq_req_expired(rq, expired)) {
1616 expired->has_timedout_rq = true;
1622 static bool blk_mq_handle_expired(struct request *rq, void *priv)
1624 struct blk_expired_data *expired = priv;
1626 if (blk_mq_req_expired(rq, expired))
1627 blk_mq_rq_timed_out(rq);
1631 static void blk_mq_timeout_work(struct work_struct *work)
1633 struct request_queue *q =
1634 container_of(work, struct request_queue, timeout_work);
1635 struct blk_expired_data expired = {
1636 .timeout_start = jiffies,
1638 struct blk_mq_hw_ctx *hctx;
1641 /* A deadlock might occur if a request is stuck requiring a
1642 * timeout at the same time a queue freeze is waiting
1643 * completion, since the timeout code would not be able to
1644 * acquire the queue reference here.
1646 * That's why we don't use blk_queue_enter here; instead, we use
1647 * percpu_ref_tryget directly, because we need to be able to
1648 * obtain a reference even in the short window between the queue
1649 * starting to freeze, by dropping the first reference in
1650 * blk_freeze_queue_start, and the moment the last request is
1651 * consumed, marked by the instant q_usage_counter reaches
1654 if (!percpu_ref_tryget(&q->q_usage_counter))
1657 /* check if there is any timed-out request */
1658 blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
1659 if (expired.has_timedout_rq) {
1661 * Before walking tags, we must ensure any submit started
1662 * before the current time has finished. Since the submit
1663 * uses srcu or rcu, wait for a synchronization point to
1664 * ensure all running submits have finished
1666 blk_mq_wait_quiesce_done(q->tag_set);
1669 blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired);
1672 if (expired.next != 0) {
1673 mod_timer(&q->timeout, expired.next);
1676 * Request timeouts are handled as a forward rolling timer. If
1677 * we end up here it means that no requests are pending and
1678 * also that no request has been pending for a while. Mark
1679 * each hctx as idle.
1681 queue_for_each_hw_ctx(q, hctx, i) {
1682 /* the hctx may be unmapped, so check it here */
1683 if (blk_mq_hw_queue_mapped(hctx))
1684 blk_mq_tag_idle(hctx);
1690 struct flush_busy_ctx_data {
1691 struct blk_mq_hw_ctx *hctx;
1692 struct list_head *list;
1695 static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
1697 struct flush_busy_ctx_data *flush_data = data;
1698 struct blk_mq_hw_ctx *hctx = flush_data->hctx;
1699 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1700 enum hctx_type type = hctx->type;
1702 spin_lock(&ctx->lock);
1703 list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
1704 sbitmap_clear_bit(sb, bitnr);
1705 spin_unlock(&ctx->lock);
1710 * Process software queues that have been marked busy, splicing them
1711 * to the for-dispatch
1713 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
1715 struct flush_busy_ctx_data data = {
1720 sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
1722 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
1724 struct dispatch_rq_data {
1725 struct blk_mq_hw_ctx *hctx;
1729 static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
1732 struct dispatch_rq_data *dispatch_data = data;
1733 struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
1734 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1735 enum hctx_type type = hctx->type;
1737 spin_lock(&ctx->lock);
1738 if (!list_empty(&ctx->rq_lists[type])) {
1739 dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
1740 list_del_init(&dispatch_data->rq->queuelist);
1741 if (list_empty(&ctx->rq_lists[type]))
1742 sbitmap_clear_bit(sb, bitnr);
1744 spin_unlock(&ctx->lock);
1746 return !dispatch_data->rq;
1749 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
1750 struct blk_mq_ctx *start)
1752 unsigned off = start ? start->index_hw[hctx->type] : 0;
1753 struct dispatch_rq_data data = {
1758 __sbitmap_for_each_set(&hctx->ctx_map, off,
1759 dispatch_rq_from_ctx, &data);
1764 bool __blk_mq_alloc_driver_tag(struct request *rq)
1766 struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
1767 unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
1770 blk_mq_tag_busy(rq->mq_hctx);
1772 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
1773 bt = &rq->mq_hctx->tags->breserved_tags;
1776 if (!hctx_may_queue(rq->mq_hctx, bt))
1780 tag = __sbitmap_queue_get(bt);
1781 if (tag == BLK_MQ_NO_TAG)
1784 rq->tag = tag + tag_offset;
1785 blk_mq_inc_active_requests(rq->mq_hctx);
1789 static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
1790 int flags, void *key)
1792 struct blk_mq_hw_ctx *hctx;
1794 hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
1796 spin_lock(&hctx->dispatch_wait_lock);
1797 if (!list_empty(&wait->entry)) {
1798 struct sbitmap_queue *sbq;
1800 list_del_init(&wait->entry);
1801 sbq = &hctx->tags->bitmap_tags;
1802 atomic_dec(&sbq->ws_active);
1804 spin_unlock(&hctx->dispatch_wait_lock);
1806 blk_mq_run_hw_queue(hctx, true);
1811 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1812 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1813 * restart. For both cases, take care to check the condition again after
1814 * marking us as waiting.
1816 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
1819 struct sbitmap_queue *sbq;
1820 struct wait_queue_head *wq;
1821 wait_queue_entry_t *wait;
1824 if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
1825 !(blk_mq_is_shared_tags(hctx->flags))) {
1826 blk_mq_sched_mark_restart_hctx(hctx);
1829 * It's possible that a tag was freed in the window between the
1830 * allocation failure and adding the hardware queue to the wait
1833 * Don't clear RESTART here, someone else could have set it.
1834 * At most this will cost an extra queue run.
1836 return blk_mq_get_driver_tag(rq);
1839 wait = &hctx->dispatch_wait;
1840 if (!list_empty_careful(&wait->entry))
1843 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag))
1844 sbq = &hctx->tags->breserved_tags;
1846 sbq = &hctx->tags->bitmap_tags;
1847 wq = &bt_wait_ptr(sbq, hctx)->wait;
1849 spin_lock_irq(&wq->lock);
1850 spin_lock(&hctx->dispatch_wait_lock);
1851 if (!list_empty(&wait->entry)) {
1852 spin_unlock(&hctx->dispatch_wait_lock);
1853 spin_unlock_irq(&wq->lock);
1857 atomic_inc(&sbq->ws_active);
1858 wait->flags &= ~WQ_FLAG_EXCLUSIVE;
1859 __add_wait_queue(wq, wait);
1862 * It's possible that a tag was freed in the window between the
1863 * allocation failure and adding the hardware queue to the wait
1866 ret = blk_mq_get_driver_tag(rq);
1868 spin_unlock(&hctx->dispatch_wait_lock);
1869 spin_unlock_irq(&wq->lock);
1874 * We got a tag, remove ourselves from the wait queue to ensure
1875 * someone else gets the wakeup.
1877 list_del_init(&wait->entry);
1878 atomic_dec(&sbq->ws_active);
1879 spin_unlock(&hctx->dispatch_wait_lock);
1880 spin_unlock_irq(&wq->lock);
1885 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1886 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1888 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1889 * - EWMA is one simple way to compute running average value
1890 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1891 * - take 4 as factor for avoiding to get too small(0) result, and this
1892 * factor doesn't matter because EWMA decreases exponentially
1894 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
1898 ewma = hctx->dispatch_busy;
1903 ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
1905 ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
1906 ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
1908 hctx->dispatch_busy = ewma;
1911 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1913 static void blk_mq_handle_dev_resource(struct request *rq,
1914 struct list_head *list)
1916 list_add(&rq->queuelist, list);
1917 __blk_mq_requeue_request(rq);
1920 static void blk_mq_handle_zone_resource(struct request *rq,
1921 struct list_head *zone_list)
1924 * If we end up here it is because we cannot dispatch a request to a
1925 * specific zone due to LLD level zone-write locking or other zone
1926 * related resource not being available. In this case, set the request
1927 * aside in zone_list for retrying it later.
1929 list_add(&rq->queuelist, zone_list);
1930 __blk_mq_requeue_request(rq);
1933 enum prep_dispatch {
1935 PREP_DISPATCH_NO_TAG,
1936 PREP_DISPATCH_NO_BUDGET,
1939 static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
1942 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1943 int budget_token = -1;
1946 budget_token = blk_mq_get_dispatch_budget(rq->q);
1947 if (budget_token < 0) {
1948 blk_mq_put_driver_tag(rq);
1949 return PREP_DISPATCH_NO_BUDGET;
1951 blk_mq_set_rq_budget_token(rq, budget_token);
1954 if (!blk_mq_get_driver_tag(rq)) {
1956 * The initial allocation attempt failed, so we need to
1957 * rerun the hardware queue when a tag is freed. The
1958 * waitqueue takes care of that. If the queue is run
1959 * before we add this entry back on the dispatch list,
1960 * we'll re-run it below.
1962 if (!blk_mq_mark_tag_wait(hctx, rq)) {
1964 * All budgets not got from this function will be put
1965 * together during handling partial dispatch
1968 blk_mq_put_dispatch_budget(rq->q, budget_token);
1969 return PREP_DISPATCH_NO_TAG;
1973 return PREP_DISPATCH_OK;
1976 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1977 static void blk_mq_release_budgets(struct request_queue *q,
1978 struct list_head *list)
1982 list_for_each_entry(rq, list, queuelist) {
1983 int budget_token = blk_mq_get_rq_budget_token(rq);
1985 if (budget_token >= 0)
1986 blk_mq_put_dispatch_budget(q, budget_token);
1991 * blk_mq_commit_rqs will notify driver using bd->last that there is no
1992 * more requests. (See comment in struct blk_mq_ops for commit_rqs for
1994 * Attention, we should explicitly call this in unusual cases:
1995 * 1) did not queue everything initially scheduled to queue
1996 * 2) the last attempt to queue a request failed
1998 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued,
2001 if (hctx->queue->mq_ops->commit_rqs && queued) {
2002 trace_block_unplug(hctx->queue, queued, !from_schedule);
2003 hctx->queue->mq_ops->commit_rqs(hctx);
2008 * Returns true if we did some work AND can potentially do more.
2010 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
2011 unsigned int nr_budgets)
2013 enum prep_dispatch prep;
2014 struct request_queue *q = hctx->queue;
2017 blk_status_t ret = BLK_STS_OK;
2018 LIST_HEAD(zone_list);
2019 bool needs_resource = false;
2021 if (list_empty(list))
2025 * Now process all the entries, sending them to the driver.
2029 struct blk_mq_queue_data bd;
2031 rq = list_first_entry(list, struct request, queuelist);
2033 WARN_ON_ONCE(hctx != rq->mq_hctx);
2034 prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
2035 if (prep != PREP_DISPATCH_OK)
2038 list_del_init(&rq->queuelist);
2041 bd.last = list_empty(list);
2044 * once the request is queued to lld, no need to cover the
2049 ret = q->mq_ops->queue_rq(hctx, &bd);
2054 case BLK_STS_RESOURCE:
2055 needs_resource = true;
2057 case BLK_STS_DEV_RESOURCE:
2058 blk_mq_handle_dev_resource(rq, list);
2060 case BLK_STS_ZONE_RESOURCE:
2062 * Move the request to zone_list and keep going through
2063 * the dispatch list to find more requests the drive can
2066 blk_mq_handle_zone_resource(rq, &zone_list);
2067 needs_resource = true;
2070 blk_mq_end_request(rq, ret);
2072 } while (!list_empty(list));
2074 if (!list_empty(&zone_list))
2075 list_splice_tail_init(&zone_list, list);
2077 /* If we didn't flush the entire list, we could have told the driver
2078 * there was more coming, but that turned out to be a lie.
2080 if (!list_empty(list) || ret != BLK_STS_OK)
2081 blk_mq_commit_rqs(hctx, queued, false);
2084 * Any items that need requeuing? Stuff them into hctx->dispatch,
2085 * that is where we will continue on next queue run.
2087 if (!list_empty(list)) {
2089 /* For non-shared tags, the RESTART check will suffice */
2090 bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
2091 ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||
2092 blk_mq_is_shared_tags(hctx->flags));
2095 blk_mq_release_budgets(q, list);
2097 spin_lock(&hctx->lock);
2098 list_splice_tail_init(list, &hctx->dispatch);
2099 spin_unlock(&hctx->lock);
2102 * Order adding requests to hctx->dispatch and checking
2103 * SCHED_RESTART flag. The pair of this smp_mb() is the one
2104 * in blk_mq_sched_restart(). Avoid restart code path to
2105 * miss the new added requests to hctx->dispatch, meantime
2106 * SCHED_RESTART is observed here.
2111 * If SCHED_RESTART was set by the caller of this function and
2112 * it is no longer set that means that it was cleared by another
2113 * thread and hence that a queue rerun is needed.
2115 * If 'no_tag' is set, that means that we failed getting
2116 * a driver tag with an I/O scheduler attached. If our dispatch
2117 * waitqueue is no longer active, ensure that we run the queue
2118 * AFTER adding our entries back to the list.
2120 * If no I/O scheduler has been configured it is possible that
2121 * the hardware queue got stopped and restarted before requests
2122 * were pushed back onto the dispatch list. Rerun the queue to
2123 * avoid starvation. Notes:
2124 * - blk_mq_run_hw_queue() checks whether or not a queue has
2125 * been stopped before rerunning a queue.
2126 * - Some but not all block drivers stop a queue before
2127 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
2130 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
2131 * bit is set, run queue after a delay to avoid IO stalls
2132 * that could otherwise occur if the queue is idle. We'll do
2133 * similar if we couldn't get budget or couldn't lock a zone
2134 * and SCHED_RESTART is set.
2136 needs_restart = blk_mq_sched_needs_restart(hctx);
2137 if (prep == PREP_DISPATCH_NO_BUDGET)
2138 needs_resource = true;
2139 if (!needs_restart ||
2140 (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
2141 blk_mq_run_hw_queue(hctx, true);
2142 else if (needs_resource)
2143 blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
2145 blk_mq_update_dispatch_busy(hctx, true);
2149 blk_mq_update_dispatch_busy(hctx, false);
2153 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
2155 int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
2157 if (cpu >= nr_cpu_ids)
2158 cpu = cpumask_first(hctx->cpumask);
2163 * It'd be great if the workqueue API had a way to pass
2164 * in a mask and had some smarts for more clever placement.
2165 * For now we just round-robin here, switching for every
2166 * BLK_MQ_CPU_WORK_BATCH queued items.
2168 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
2171 int next_cpu = hctx->next_cpu;
2173 if (hctx->queue->nr_hw_queues == 1)
2174 return WORK_CPU_UNBOUND;
2176 if (--hctx->next_cpu_batch <= 0) {
2178 next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
2180 if (next_cpu >= nr_cpu_ids)
2181 next_cpu = blk_mq_first_mapped_cpu(hctx);
2182 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
2186 * Do unbound schedule if we can't find a online CPU for this hctx,
2187 * and it should only happen in the path of handling CPU DEAD.
2189 if (!cpu_online(next_cpu)) {
2196 * Make sure to re-select CPU next time once after CPUs
2197 * in hctx->cpumask become online again.
2199 hctx->next_cpu = next_cpu;
2200 hctx->next_cpu_batch = 1;
2201 return WORK_CPU_UNBOUND;
2204 hctx->next_cpu = next_cpu;
2209 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
2210 * @hctx: Pointer to the hardware queue to run.
2211 * @msecs: Milliseconds of delay to wait before running the queue.
2213 * Run a hardware queue asynchronously with a delay of @msecs.
2215 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
2217 if (unlikely(blk_mq_hctx_stopped(hctx)))
2219 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
2220 msecs_to_jiffies(msecs));
2222 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
2225 * blk_mq_run_hw_queue - Start to run a hardware queue.
2226 * @hctx: Pointer to the hardware queue to run.
2227 * @async: If we want to run the queue asynchronously.
2229 * Check if the request queue is not in a quiesced state and if there are
2230 * pending requests to be sent. If this is true, run the queue to send requests
2233 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2238 * We can't run the queue inline with interrupts disabled.
2240 WARN_ON_ONCE(!async && in_interrupt());
2242 might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING);
2245 * When queue is quiesced, we may be switching io scheduler, or
2246 * updating nr_hw_queues, or other things, and we can't run queue
2247 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
2249 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
2252 __blk_mq_run_dispatch_ops(hctx->queue, false,
2253 need_run = !blk_queue_quiesced(hctx->queue) &&
2254 blk_mq_hctx_has_pending(hctx));
2259 if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) {
2260 blk_mq_delay_run_hw_queue(hctx, 0);
2264 blk_mq_run_dispatch_ops(hctx->queue,
2265 blk_mq_sched_dispatch_requests(hctx));
2267 EXPORT_SYMBOL(blk_mq_run_hw_queue);
2270 * Return prefered queue to dispatch from (if any) for non-mq aware IO
2273 static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
2275 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
2277 * If the IO scheduler does not respect hardware queues when
2278 * dispatching, we just don't bother with multiple HW queues and
2279 * dispatch from hctx for the current CPU since running multiple queues
2280 * just causes lock contention inside the scheduler and pointless cache
2283 struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT];
2285 if (!blk_mq_hctx_stopped(hctx))
2291 * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
2292 * @q: Pointer to the request queue to run.
2293 * @async: If we want to run the queue asynchronously.
2295 void blk_mq_run_hw_queues(struct request_queue *q, bool async)
2297 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2301 if (blk_queue_sq_sched(q))
2302 sq_hctx = blk_mq_get_sq_hctx(q);
2303 queue_for_each_hw_ctx(q, hctx, i) {
2304 if (blk_mq_hctx_stopped(hctx))
2307 * Dispatch from this hctx either if there's no hctx preferred
2308 * by IO scheduler or if it has requests that bypass the
2311 if (!sq_hctx || sq_hctx == hctx ||
2312 !list_empty_careful(&hctx->dispatch))
2313 blk_mq_run_hw_queue(hctx, async);
2316 EXPORT_SYMBOL(blk_mq_run_hw_queues);
2319 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
2320 * @q: Pointer to the request queue to run.
2321 * @msecs: Milliseconds of delay to wait before running the queues.
2323 void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
2325 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2329 if (blk_queue_sq_sched(q))
2330 sq_hctx = blk_mq_get_sq_hctx(q);
2331 queue_for_each_hw_ctx(q, hctx, i) {
2332 if (blk_mq_hctx_stopped(hctx))
2335 * If there is already a run_work pending, leave the
2336 * pending delay untouched. Otherwise, a hctx can stall
2337 * if another hctx is re-delaying the other's work
2338 * before the work executes.
2340 if (delayed_work_pending(&hctx->run_work))
2343 * Dispatch from this hctx either if there's no hctx preferred
2344 * by IO scheduler or if it has requests that bypass the
2347 if (!sq_hctx || sq_hctx == hctx ||
2348 !list_empty_careful(&hctx->dispatch))
2349 blk_mq_delay_run_hw_queue(hctx, msecs);
2352 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
2355 * This function is often used for pausing .queue_rq() by driver when
2356 * there isn't enough resource or some conditions aren't satisfied, and
2357 * BLK_STS_RESOURCE is usually returned.
2359 * We do not guarantee that dispatch can be drained or blocked
2360 * after blk_mq_stop_hw_queue() returns. Please use
2361 * blk_mq_quiesce_queue() for that requirement.
2363 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
2365 cancel_delayed_work(&hctx->run_work);
2367 set_bit(BLK_MQ_S_STOPPED, &hctx->state);
2369 EXPORT_SYMBOL(blk_mq_stop_hw_queue);
2372 * This function is often used for pausing .queue_rq() by driver when
2373 * there isn't enough resource or some conditions aren't satisfied, and
2374 * BLK_STS_RESOURCE is usually returned.
2376 * We do not guarantee that dispatch can be drained or blocked
2377 * after blk_mq_stop_hw_queues() returns. Please use
2378 * blk_mq_quiesce_queue() for that requirement.
2380 void blk_mq_stop_hw_queues(struct request_queue *q)
2382 struct blk_mq_hw_ctx *hctx;
2385 queue_for_each_hw_ctx(q, hctx, i)
2386 blk_mq_stop_hw_queue(hctx);
2388 EXPORT_SYMBOL(blk_mq_stop_hw_queues);
2390 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
2392 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2394 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
2396 EXPORT_SYMBOL(blk_mq_start_hw_queue);
2398 void blk_mq_start_hw_queues(struct request_queue *q)
2400 struct blk_mq_hw_ctx *hctx;
2403 queue_for_each_hw_ctx(q, hctx, i)
2404 blk_mq_start_hw_queue(hctx);
2406 EXPORT_SYMBOL(blk_mq_start_hw_queues);
2408 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2410 if (!blk_mq_hctx_stopped(hctx))
2413 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2414 blk_mq_run_hw_queue(hctx, async);
2416 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
2418 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
2420 struct blk_mq_hw_ctx *hctx;
2423 queue_for_each_hw_ctx(q, hctx, i)
2424 blk_mq_start_stopped_hw_queue(hctx, async ||
2425 (hctx->flags & BLK_MQ_F_BLOCKING));
2427 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
2429 static void blk_mq_run_work_fn(struct work_struct *work)
2431 struct blk_mq_hw_ctx *hctx =
2432 container_of(work, struct blk_mq_hw_ctx, run_work.work);
2434 blk_mq_run_dispatch_ops(hctx->queue,
2435 blk_mq_sched_dispatch_requests(hctx));
2439 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2440 * @rq: Pointer to request to be inserted.
2441 * @flags: BLK_MQ_INSERT_*
2443 * Should only be used carefully, when the caller knows we want to
2444 * bypass a potential IO scheduler on the target device.
2446 static void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags)
2448 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2450 spin_lock(&hctx->lock);
2451 if (flags & BLK_MQ_INSERT_AT_HEAD)
2452 list_add(&rq->queuelist, &hctx->dispatch);
2454 list_add_tail(&rq->queuelist, &hctx->dispatch);
2455 spin_unlock(&hctx->lock);
2458 static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
2459 struct blk_mq_ctx *ctx, struct list_head *list,
2460 bool run_queue_async)
2463 enum hctx_type type = hctx->type;
2466 * Try to issue requests directly if the hw queue isn't busy to save an
2467 * extra enqueue & dequeue to the sw queue.
2469 if (!hctx->dispatch_busy && !run_queue_async) {
2470 blk_mq_run_dispatch_ops(hctx->queue,
2471 blk_mq_try_issue_list_directly(hctx, list));
2472 if (list_empty(list))
2477 * preemption doesn't flush plug list, so it's possible ctx->cpu is
2480 list_for_each_entry(rq, list, queuelist) {
2481 BUG_ON(rq->mq_ctx != ctx);
2482 trace_block_rq_insert(rq);
2483 if (rq->cmd_flags & REQ_NOWAIT)
2484 run_queue_async = true;
2487 spin_lock(&ctx->lock);
2488 list_splice_tail_init(list, &ctx->rq_lists[type]);
2489 blk_mq_hctx_mark_pending(hctx, ctx);
2490 spin_unlock(&ctx->lock);
2492 blk_mq_run_hw_queue(hctx, run_queue_async);
2495 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
2497 struct request_queue *q = rq->q;
2498 struct blk_mq_ctx *ctx = rq->mq_ctx;
2499 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2501 if (blk_rq_is_passthrough(rq)) {
2503 * Passthrough request have to be added to hctx->dispatch
2504 * directly. The device may be in a situation where it can't
2505 * handle FS request, and always returns BLK_STS_RESOURCE for
2506 * them, which gets them added to hctx->dispatch.
2508 * If a passthrough request is required to unblock the queues,
2509 * and it is added to the scheduler queue, there is no chance to
2510 * dispatch it given we prioritize requests in hctx->dispatch.
2512 blk_mq_request_bypass_insert(rq, flags);
2513 } else if (req_op(rq) == REQ_OP_FLUSH) {
2515 * Firstly normal IO request is inserted to scheduler queue or
2516 * sw queue, meantime we add flush request to dispatch queue(
2517 * hctx->dispatch) directly and there is at most one in-flight
2518 * flush request for each hw queue, so it doesn't matter to add
2519 * flush request to tail or front of the dispatch queue.
2521 * Secondly in case of NCQ, flush request belongs to non-NCQ
2522 * command, and queueing it will fail when there is any
2523 * in-flight normal IO request(NCQ command). When adding flush
2524 * rq to the front of hctx->dispatch, it is easier to introduce
2525 * extra time to flush rq's latency because of S_SCHED_RESTART
2526 * compared with adding to the tail of dispatch queue, then
2527 * chance of flush merge is increased, and less flush requests
2528 * will be issued to controller. It is observed that ~10% time
2529 * is saved in blktests block/004 on disk attached to AHCI/NCQ
2530 * drive when adding flush rq to the front of hctx->dispatch.
2532 * Simply queue flush rq to the front of hctx->dispatch so that
2533 * intensive flush workloads can benefit in case of NCQ HW.
2535 blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD);
2536 } else if (q->elevator) {
2539 WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG);
2541 list_add(&rq->queuelist, &list);
2542 q->elevator->type->ops.insert_requests(hctx, &list, flags);
2544 trace_block_rq_insert(rq);
2546 spin_lock(&ctx->lock);
2547 if (flags & BLK_MQ_INSERT_AT_HEAD)
2548 list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]);
2550 list_add_tail(&rq->queuelist,
2551 &ctx->rq_lists[hctx->type]);
2552 blk_mq_hctx_mark_pending(hctx, ctx);
2553 spin_unlock(&ctx->lock);
2557 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
2558 unsigned int nr_segs)
2562 if (bio->bi_opf & REQ_RAHEAD)
2563 rq->cmd_flags |= REQ_FAILFAST_MASK;
2565 rq->__sector = bio->bi_iter.bi_sector;
2566 blk_rq_bio_prep(rq, bio, nr_segs);
2568 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2569 err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
2572 blk_account_io_start(rq);
2575 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
2576 struct request *rq, bool last)
2578 struct request_queue *q = rq->q;
2579 struct blk_mq_queue_data bd = {
2586 * For OK queue, we are done. For error, caller may kill it.
2587 * Any other error (busy), just add it to our list as we
2588 * previously would have done.
2590 ret = q->mq_ops->queue_rq(hctx, &bd);
2593 blk_mq_update_dispatch_busy(hctx, false);
2595 case BLK_STS_RESOURCE:
2596 case BLK_STS_DEV_RESOURCE:
2597 blk_mq_update_dispatch_busy(hctx, true);
2598 __blk_mq_requeue_request(rq);
2601 blk_mq_update_dispatch_busy(hctx, false);
2608 static bool blk_mq_get_budget_and_tag(struct request *rq)
2612 budget_token = blk_mq_get_dispatch_budget(rq->q);
2613 if (budget_token < 0)
2615 blk_mq_set_rq_budget_token(rq, budget_token);
2616 if (!blk_mq_get_driver_tag(rq)) {
2617 blk_mq_put_dispatch_budget(rq->q, budget_token);
2624 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2625 * @hctx: Pointer of the associated hardware queue.
2626 * @rq: Pointer to request to be sent.
2628 * If the device has enough resources to accept a new request now, send the
2629 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2630 * we can try send it another time in the future. Requests inserted at this
2631 * queue have higher priority.
2633 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
2638 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2639 blk_mq_insert_request(rq, 0);
2643 if ((rq->rq_flags & RQF_USE_SCHED) || !blk_mq_get_budget_and_tag(rq)) {
2644 blk_mq_insert_request(rq, 0);
2645 blk_mq_run_hw_queue(hctx, rq->cmd_flags & REQ_NOWAIT);
2649 ret = __blk_mq_issue_directly(hctx, rq, true);
2653 case BLK_STS_RESOURCE:
2654 case BLK_STS_DEV_RESOURCE:
2655 blk_mq_request_bypass_insert(rq, 0);
2656 blk_mq_run_hw_queue(hctx, false);
2659 blk_mq_end_request(rq, ret);
2664 static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
2666 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2668 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2669 blk_mq_insert_request(rq, 0);
2673 if (!blk_mq_get_budget_and_tag(rq))
2674 return BLK_STS_RESOURCE;
2675 return __blk_mq_issue_directly(hctx, rq, last);
2678 static void blk_mq_plug_issue_direct(struct blk_plug *plug)
2680 struct blk_mq_hw_ctx *hctx = NULL;
2683 blk_status_t ret = BLK_STS_OK;
2685 while ((rq = rq_list_pop(&plug->mq_list))) {
2686 bool last = rq_list_empty(plug->mq_list);
2688 if (hctx != rq->mq_hctx) {
2690 blk_mq_commit_rqs(hctx, queued, false);
2696 ret = blk_mq_request_issue_directly(rq, last);
2701 case BLK_STS_RESOURCE:
2702 case BLK_STS_DEV_RESOURCE:
2703 blk_mq_request_bypass_insert(rq, 0);
2704 blk_mq_run_hw_queue(hctx, false);
2707 blk_mq_end_request(rq, ret);
2713 if (ret != BLK_STS_OK)
2714 blk_mq_commit_rqs(hctx, queued, false);
2717 static void __blk_mq_flush_plug_list(struct request_queue *q,
2718 struct blk_plug *plug)
2720 if (blk_queue_quiesced(q))
2722 q->mq_ops->queue_rqs(&plug->mq_list);
2725 static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
2727 struct blk_mq_hw_ctx *this_hctx = NULL;
2728 struct blk_mq_ctx *this_ctx = NULL;
2729 struct request *requeue_list = NULL;
2730 struct request **requeue_lastp = &requeue_list;
2731 unsigned int depth = 0;
2732 bool is_passthrough = false;
2736 struct request *rq = rq_list_pop(&plug->mq_list);
2739 this_hctx = rq->mq_hctx;
2740 this_ctx = rq->mq_ctx;
2741 is_passthrough = blk_rq_is_passthrough(rq);
2742 } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx ||
2743 is_passthrough != blk_rq_is_passthrough(rq)) {
2744 rq_list_add_tail(&requeue_lastp, rq);
2747 list_add(&rq->queuelist, &list);
2749 } while (!rq_list_empty(plug->mq_list));
2751 plug->mq_list = requeue_list;
2752 trace_block_unplug(this_hctx->queue, depth, !from_sched);
2754 percpu_ref_get(&this_hctx->queue->q_usage_counter);
2755 /* passthrough requests should never be issued to the I/O scheduler */
2756 if (is_passthrough) {
2757 spin_lock(&this_hctx->lock);
2758 list_splice_tail_init(&list, &this_hctx->dispatch);
2759 spin_unlock(&this_hctx->lock);
2760 blk_mq_run_hw_queue(this_hctx, from_sched);
2761 } else if (this_hctx->queue->elevator) {
2762 this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
2764 blk_mq_run_hw_queue(this_hctx, from_sched);
2766 blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched);
2768 percpu_ref_put(&this_hctx->queue->q_usage_counter);
2771 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
2776 * We may have been called recursively midway through handling
2777 * plug->mq_list via a schedule() in the driver's queue_rq() callback.
2778 * To avoid mq_list changing under our feet, clear rq_count early and
2779 * bail out specifically if rq_count is 0 rather than checking
2780 * whether the mq_list is empty.
2782 if (plug->rq_count == 0)
2786 if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
2787 struct request_queue *q;
2789 rq = rq_list_peek(&plug->mq_list);
2793 * Peek first request and see if we have a ->queue_rqs() hook.
2794 * If we do, we can dispatch the whole plug list in one go. We
2795 * already know at this point that all requests belong to the
2796 * same queue, caller must ensure that's the case.
2798 if (q->mq_ops->queue_rqs) {
2799 blk_mq_run_dispatch_ops(q,
2800 __blk_mq_flush_plug_list(q, plug));
2801 if (rq_list_empty(plug->mq_list))
2805 blk_mq_run_dispatch_ops(q,
2806 blk_mq_plug_issue_direct(plug));
2807 if (rq_list_empty(plug->mq_list))
2812 blk_mq_dispatch_plug_list(plug, from_schedule);
2813 } while (!rq_list_empty(plug->mq_list));
2816 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
2817 struct list_head *list)
2820 blk_status_t ret = BLK_STS_OK;
2822 while (!list_empty(list)) {
2823 struct request *rq = list_first_entry(list, struct request,
2826 list_del_init(&rq->queuelist);
2827 ret = blk_mq_request_issue_directly(rq, list_empty(list));
2832 case BLK_STS_RESOURCE:
2833 case BLK_STS_DEV_RESOURCE:
2834 blk_mq_request_bypass_insert(rq, 0);
2835 if (list_empty(list))
2836 blk_mq_run_hw_queue(hctx, false);
2839 blk_mq_end_request(rq, ret);
2845 if (ret != BLK_STS_OK)
2846 blk_mq_commit_rqs(hctx, queued, false);
2849 static bool blk_mq_attempt_bio_merge(struct request_queue *q,
2850 struct bio *bio, unsigned int nr_segs)
2852 if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
2853 if (blk_attempt_plug_merge(q, bio, nr_segs))
2855 if (blk_mq_sched_bio_merge(q, bio, nr_segs))
2861 static struct request *blk_mq_get_new_requests(struct request_queue *q,
2862 struct blk_plug *plug,
2866 struct blk_mq_alloc_data data = {
2869 .cmd_flags = bio->bi_opf,
2873 if (blk_mq_attempt_bio_merge(q, bio, nsegs))
2876 rq_qos_throttle(q, bio);
2879 data.nr_tags = plug->nr_ios;
2881 data.cached_rq = &plug->cached_rq;
2884 rq = __blk_mq_alloc_requests(&data);
2887 rq_qos_cleanup(q, bio);
2888 if (bio->bi_opf & REQ_NOWAIT)
2889 bio_wouldblock_error(bio);
2893 /* return true if this @rq can be used for @bio */
2894 static bool blk_mq_can_use_cached_rq(struct request *rq, struct blk_plug *plug,
2897 enum hctx_type type = blk_mq_get_hctx_type(bio->bi_opf);
2898 enum hctx_type hctx_type = rq->mq_hctx->type;
2900 WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq);
2902 if (type != hctx_type &&
2903 !(type == HCTX_TYPE_READ && hctx_type == HCTX_TYPE_DEFAULT))
2905 if (op_is_flush(rq->cmd_flags) != op_is_flush(bio->bi_opf))
2909 * If any qos ->throttle() end up blocking, we will have flushed the
2910 * plug and hence killed the cached_rq list as well. Pop this entry
2911 * before we throttle.
2913 plug->cached_rq = rq_list_next(rq);
2914 rq_qos_throttle(rq->q, bio);
2916 blk_mq_rq_time_init(rq, 0);
2917 rq->cmd_flags = bio->bi_opf;
2918 INIT_LIST_HEAD(&rq->queuelist);
2922 static void bio_set_ioprio(struct bio *bio)
2924 /* Nobody set ioprio so far? Initialize it based on task's nice value */
2925 if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
2926 bio->bi_ioprio = get_current_ioprio();
2927 blkcg_set_ioprio(bio);
2931 * blk_mq_submit_bio - Create and send a request to block device.
2932 * @bio: Bio pointer.
2934 * Builds up a request structure from @q and @bio and send to the device. The
2935 * request may not be queued directly to hardware if:
2936 * * This request can be merged with another one
2937 * * We want to place request at plug queue for possible future merging
2938 * * There is an IO scheduler active at this queue
2940 * It will not queue the request if there is an error with the bio, or at the
2943 void blk_mq_submit_bio(struct bio *bio)
2945 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
2946 struct blk_plug *plug = blk_mq_plug(bio);
2947 const int is_sync = op_is_sync(bio->bi_opf);
2948 struct blk_mq_hw_ctx *hctx;
2949 struct request *rq = NULL;
2950 unsigned int nr_segs = 1;
2953 bio = blk_queue_bounce(bio, q);
2954 if (bio_may_exceed_limits(bio, &q->limits)) {
2955 bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
2960 bio_set_ioprio(bio);
2963 rq = rq_list_peek(&plug->cached_rq);
2964 if (rq && rq->q != q)
2968 if (!bio_integrity_prep(bio))
2970 if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
2972 if (blk_mq_can_use_cached_rq(rq, plug, bio))
2974 percpu_ref_get(&q->q_usage_counter);
2976 if (unlikely(bio_queue_enter(bio)))
2978 if (!bio_integrity_prep(bio))
2982 rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
2983 if (unlikely(!rq)) {
2990 trace_block_getrq(bio);
2992 rq_qos_track(q, rq, bio);
2994 blk_mq_bio_to_request(rq, bio, nr_segs);
2996 ret = blk_crypto_rq_get_keyslot(rq);
2997 if (ret != BLK_STS_OK) {
2998 bio->bi_status = ret;
3000 blk_mq_free_request(rq);
3004 if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq))
3008 blk_add_rq_to_plug(plug, rq);
3013 if ((rq->rq_flags & RQF_USE_SCHED) ||
3014 (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) {
3015 blk_mq_insert_request(rq, 0);
3016 blk_mq_run_hw_queue(hctx, true);
3018 blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq));
3022 #ifdef CONFIG_BLK_MQ_STACKING
3024 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
3025 * @rq: the request being queued
3027 blk_status_t blk_insert_cloned_request(struct request *rq)
3029 struct request_queue *q = rq->q;
3030 unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
3031 unsigned int max_segments = blk_rq_get_max_segments(rq);
3034 if (blk_rq_sectors(rq) > max_sectors) {
3036 * SCSI device does not have a good way to return if
3037 * Write Same/Zero is actually supported. If a device rejects
3038 * a non-read/write command (discard, write same,etc.) the
3039 * low-level device driver will set the relevant queue limit to
3040 * 0 to prevent blk-lib from issuing more of the offending
3041 * operations. Commands queued prior to the queue limit being
3042 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
3043 * errors being propagated to upper layers.
3045 if (max_sectors == 0)
3046 return BLK_STS_NOTSUPP;
3048 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
3049 __func__, blk_rq_sectors(rq), max_sectors);
3050 return BLK_STS_IOERR;
3054 * The queue settings related to segment counting may differ from the
3057 rq->nr_phys_segments = blk_recalc_rq_segments(rq);
3058 if (rq->nr_phys_segments > max_segments) {
3059 printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n",
3060 __func__, rq->nr_phys_segments, max_segments);
3061 return BLK_STS_IOERR;
3064 if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq)))
3065 return BLK_STS_IOERR;
3067 ret = blk_crypto_rq_get_keyslot(rq);
3068 if (ret != BLK_STS_OK)
3071 blk_account_io_start(rq);
3074 * Since we have a scheduler attached on the top device,
3075 * bypass a potential scheduler on the bottom device for
3078 blk_mq_run_dispatch_ops(q,
3079 ret = blk_mq_request_issue_directly(rq, true));
3081 blk_account_io_done(rq, ktime_get_ns());
3084 EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
3087 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3088 * @rq: the clone request to be cleaned up
3091 * Free all bios in @rq for a cloned request.
3093 void blk_rq_unprep_clone(struct request *rq)
3097 while ((bio = rq->bio) != NULL) {
3098 rq->bio = bio->bi_next;
3103 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
3106 * blk_rq_prep_clone - Helper function to setup clone request
3107 * @rq: the request to be setup
3108 * @rq_src: original request to be cloned
3109 * @bs: bio_set that bios for clone are allocated from
3110 * @gfp_mask: memory allocation mask for bio
3111 * @bio_ctr: setup function to be called for each clone bio.
3112 * Returns %0 for success, non %0 for failure.
3113 * @data: private data to be passed to @bio_ctr
3116 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3117 * Also, pages which the original bios are pointing to are not copied
3118 * and the cloned bios just point same pages.
3119 * So cloned bios must be completed before original bios, which means
3120 * the caller must complete @rq before @rq_src.
3122 int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
3123 struct bio_set *bs, gfp_t gfp_mask,
3124 int (*bio_ctr)(struct bio *, struct bio *, void *),
3127 struct bio *bio, *bio_src;
3132 __rq_for_each_bio(bio_src, rq_src) {
3133 bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask,
3138 if (bio_ctr && bio_ctr(bio, bio_src, data))
3142 rq->biotail->bi_next = bio;
3145 rq->bio = rq->biotail = bio;
3150 /* Copy attributes of the original request to the clone request. */
3151 rq->__sector = blk_rq_pos(rq_src);
3152 rq->__data_len = blk_rq_bytes(rq_src);
3153 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
3154 rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
3155 rq->special_vec = rq_src->special_vec;
3157 rq->nr_phys_segments = rq_src->nr_phys_segments;
3158 rq->ioprio = rq_src->ioprio;
3160 if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
3168 blk_rq_unprep_clone(rq);
3172 EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3173 #endif /* CONFIG_BLK_MQ_STACKING */
3176 * Steal bios from a request and add them to a bio list.
3177 * The request must not have been partially completed before.
3179 void blk_steal_bios(struct bio_list *list, struct request *rq)
3183 list->tail->bi_next = rq->bio;
3185 list->head = rq->bio;
3186 list->tail = rq->biotail;
3194 EXPORT_SYMBOL_GPL(blk_steal_bios);
3196 static size_t order_to_size(unsigned int order)
3198 return (size_t)PAGE_SIZE << order;
3201 /* called before freeing request pool in @tags */
3202 static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
3203 struct blk_mq_tags *tags)
3206 unsigned long flags;
3209 * There is no need to clear mapping if driver tags is not initialized
3210 * or the mapping belongs to the driver tags.
3212 if (!drv_tags || drv_tags == tags)
3215 list_for_each_entry(page, &tags->page_list, lru) {
3216 unsigned long start = (unsigned long)page_address(page);
3217 unsigned long end = start + order_to_size(page->private);
3220 for (i = 0; i < drv_tags->nr_tags; i++) {
3221 struct request *rq = drv_tags->rqs[i];
3222 unsigned long rq_addr = (unsigned long)rq;
3224 if (rq_addr >= start && rq_addr < end) {
3225 WARN_ON_ONCE(req_ref_read(rq) != 0);
3226 cmpxchg(&drv_tags->rqs[i], rq, NULL);
3232 * Wait until all pending iteration is done.
3234 * Request reference is cleared and it is guaranteed to be observed
3235 * after the ->lock is released.
3237 spin_lock_irqsave(&drv_tags->lock, flags);
3238 spin_unlock_irqrestore(&drv_tags->lock, flags);
3241 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
3242 unsigned int hctx_idx)
3244 struct blk_mq_tags *drv_tags;
3247 if (list_empty(&tags->page_list))
3250 if (blk_mq_is_shared_tags(set->flags))
3251 drv_tags = set->shared_tags;
3253 drv_tags = set->tags[hctx_idx];
3255 if (tags->static_rqs && set->ops->exit_request) {
3258 for (i = 0; i < tags->nr_tags; i++) {
3259 struct request *rq = tags->static_rqs[i];
3263 set->ops->exit_request(set, rq, hctx_idx);
3264 tags->static_rqs[i] = NULL;
3268 blk_mq_clear_rq_mapping(drv_tags, tags);
3270 while (!list_empty(&tags->page_list)) {
3271 page = list_first_entry(&tags->page_list, struct page, lru);
3272 list_del_init(&page->lru);
3274 * Remove kmemleak object previously allocated in
3275 * blk_mq_alloc_rqs().
3277 kmemleak_free(page_address(page));
3278 __free_pages(page, page->private);
3282 void blk_mq_free_rq_map(struct blk_mq_tags *tags)
3286 kfree(tags->static_rqs);
3287 tags->static_rqs = NULL;
3289 blk_mq_free_tags(tags);
3292 static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set,
3293 unsigned int hctx_idx)
3297 for (i = 0; i < set->nr_maps; i++) {
3298 unsigned int start = set->map[i].queue_offset;
3299 unsigned int end = start + set->map[i].nr_queues;
3301 if (hctx_idx >= start && hctx_idx < end)
3305 if (i >= set->nr_maps)
3306 i = HCTX_TYPE_DEFAULT;
3311 static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set,
3312 unsigned int hctx_idx)
3314 enum hctx_type type = hctx_idx_to_type(set, hctx_idx);
3316 return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx);
3319 static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
3320 unsigned int hctx_idx,
3321 unsigned int nr_tags,
3322 unsigned int reserved_tags)
3324 int node = blk_mq_get_hctx_node(set, hctx_idx);
3325 struct blk_mq_tags *tags;
3327 if (node == NUMA_NO_NODE)
3328 node = set->numa_node;
3330 tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
3331 BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
3335 tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3336 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3341 tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3342 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3344 if (!tags->static_rqs)
3352 blk_mq_free_tags(tags);
3356 static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
3357 unsigned int hctx_idx, int node)
3361 if (set->ops->init_request) {
3362 ret = set->ops->init_request(set, rq, hctx_idx, node);
3367 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
3371 static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
3372 struct blk_mq_tags *tags,
3373 unsigned int hctx_idx, unsigned int depth)
3375 unsigned int i, j, entries_per_page, max_order = 4;
3376 int node = blk_mq_get_hctx_node(set, hctx_idx);
3377 size_t rq_size, left;
3379 if (node == NUMA_NO_NODE)
3380 node = set->numa_node;
3382 INIT_LIST_HEAD(&tags->page_list);
3385 * rq_size is the size of the request plus driver payload, rounded
3386 * to the cacheline size
3388 rq_size = round_up(sizeof(struct request) + set->cmd_size,
3390 left = rq_size * depth;
3392 for (i = 0; i < depth; ) {
3393 int this_order = max_order;
3398 while (this_order && left < order_to_size(this_order - 1))
3402 page = alloc_pages_node(node,
3403 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
3409 if (order_to_size(this_order) < rq_size)
3416 page->private = this_order;
3417 list_add_tail(&page->lru, &tags->page_list);
3419 p = page_address(page);
3421 * Allow kmemleak to scan these pages as they contain pointers
3422 * to additional allocations like via ops->init_request().
3424 kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
3425 entries_per_page = order_to_size(this_order) / rq_size;
3426 to_do = min(entries_per_page, depth - i);
3427 left -= to_do * rq_size;
3428 for (j = 0; j < to_do; j++) {
3429 struct request *rq = p;
3431 tags->static_rqs[i] = rq;
3432 if (blk_mq_init_request(set, rq, hctx_idx, node)) {
3433 tags->static_rqs[i] = NULL;
3444 blk_mq_free_rqs(set, tags, hctx_idx);
3448 struct rq_iter_data {
3449 struct blk_mq_hw_ctx *hctx;
3453 static bool blk_mq_has_request(struct request *rq, void *data)
3455 struct rq_iter_data *iter_data = data;
3457 if (rq->mq_hctx != iter_data->hctx)
3459 iter_data->has_rq = true;
3463 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
3465 struct blk_mq_tags *tags = hctx->sched_tags ?
3466 hctx->sched_tags : hctx->tags;
3467 struct rq_iter_data data = {
3471 blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
3475 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
3476 struct blk_mq_hw_ctx *hctx)
3478 if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu)
3480 if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
3485 static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
3487 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3488 struct blk_mq_hw_ctx, cpuhp_online);
3490 if (!cpumask_test_cpu(cpu, hctx->cpumask) ||
3491 !blk_mq_last_cpu_in_hctx(cpu, hctx))
3495 * Prevent new request from being allocated on the current hctx.
3497 * The smp_mb__after_atomic() Pairs with the implied barrier in
3498 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
3499 * seen once we return from the tag allocator.
3501 set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3502 smp_mb__after_atomic();
3505 * Try to grab a reference to the queue and wait for any outstanding
3506 * requests. If we could not grab a reference the queue has been
3507 * frozen and there are no requests.
3509 if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
3510 while (blk_mq_hctx_has_requests(hctx))
3512 percpu_ref_put(&hctx->queue->q_usage_counter);
3518 static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
3520 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3521 struct blk_mq_hw_ctx, cpuhp_online);
3523 if (cpumask_test_cpu(cpu, hctx->cpumask))
3524 clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3529 * 'cpu' is going away. splice any existing rq_list entries from this
3530 * software queue to the hw queue dispatch list, and ensure that it
3533 static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
3535 struct blk_mq_hw_ctx *hctx;
3536 struct blk_mq_ctx *ctx;
3538 enum hctx_type type;
3540 hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
3541 if (!cpumask_test_cpu(cpu, hctx->cpumask))
3544 ctx = __blk_mq_get_ctx(hctx->queue, cpu);
3547 spin_lock(&ctx->lock);
3548 if (!list_empty(&ctx->rq_lists[type])) {
3549 list_splice_init(&ctx->rq_lists[type], &tmp);
3550 blk_mq_hctx_clear_pending(hctx, ctx);
3552 spin_unlock(&ctx->lock);
3554 if (list_empty(&tmp))
3557 spin_lock(&hctx->lock);
3558 list_splice_tail_init(&tmp, &hctx->dispatch);
3559 spin_unlock(&hctx->lock);
3561 blk_mq_run_hw_queue(hctx, true);
3565 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
3567 if (!(hctx->flags & BLK_MQ_F_STACKING))
3568 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3569 &hctx->cpuhp_online);
3570 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
3575 * Before freeing hw queue, clearing the flush request reference in
3576 * tags->rqs[] for avoiding potential UAF.
3578 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
3579 unsigned int queue_depth, struct request *flush_rq)
3582 unsigned long flags;
3584 /* The hw queue may not be mapped yet */
3588 WARN_ON_ONCE(req_ref_read(flush_rq) != 0);
3590 for (i = 0; i < queue_depth; i++)
3591 cmpxchg(&tags->rqs[i], flush_rq, NULL);
3594 * Wait until all pending iteration is done.
3596 * Request reference is cleared and it is guaranteed to be observed
3597 * after the ->lock is released.
3599 spin_lock_irqsave(&tags->lock, flags);
3600 spin_unlock_irqrestore(&tags->lock, flags);
3603 /* hctx->ctxs will be freed in queue's release handler */
3604 static void blk_mq_exit_hctx(struct request_queue *q,
3605 struct blk_mq_tag_set *set,
3606 struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
3608 struct request *flush_rq = hctx->fq->flush_rq;
3610 if (blk_mq_hw_queue_mapped(hctx))
3611 blk_mq_tag_idle(hctx);
3613 if (blk_queue_init_done(q))
3614 blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
3615 set->queue_depth, flush_rq);
3616 if (set->ops->exit_request)
3617 set->ops->exit_request(set, flush_rq, hctx_idx);
3619 if (set->ops->exit_hctx)
3620 set->ops->exit_hctx(hctx, hctx_idx);
3622 blk_mq_remove_cpuhp(hctx);
3624 xa_erase(&q->hctx_table, hctx_idx);
3626 spin_lock(&q->unused_hctx_lock);
3627 list_add(&hctx->hctx_list, &q->unused_hctx_list);
3628 spin_unlock(&q->unused_hctx_lock);
3631 static void blk_mq_exit_hw_queues(struct request_queue *q,
3632 struct blk_mq_tag_set *set, int nr_queue)
3634 struct blk_mq_hw_ctx *hctx;
3637 queue_for_each_hw_ctx(q, hctx, i) {
3640 blk_mq_exit_hctx(q, set, hctx, i);
3644 static int blk_mq_init_hctx(struct request_queue *q,
3645 struct blk_mq_tag_set *set,
3646 struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
3648 hctx->queue_num = hctx_idx;
3650 if (!(hctx->flags & BLK_MQ_F_STACKING))
3651 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3652 &hctx->cpuhp_online);
3653 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
3655 hctx->tags = set->tags[hctx_idx];
3657 if (set->ops->init_hctx &&
3658 set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
3659 goto unregister_cpu_notifier;
3661 if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
3665 if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL))
3671 if (set->ops->exit_request)
3672 set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
3674 if (set->ops->exit_hctx)
3675 set->ops->exit_hctx(hctx, hctx_idx);
3676 unregister_cpu_notifier:
3677 blk_mq_remove_cpuhp(hctx);
3681 static struct blk_mq_hw_ctx *
3682 blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
3685 struct blk_mq_hw_ctx *hctx;
3686 gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
3688 hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node);
3690 goto fail_alloc_hctx;
3692 if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
3695 atomic_set(&hctx->nr_active, 0);
3696 if (node == NUMA_NO_NODE)
3697 node = set->numa_node;
3698 hctx->numa_node = node;
3700 INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
3701 spin_lock_init(&hctx->lock);
3702 INIT_LIST_HEAD(&hctx->dispatch);
3704 hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
3706 INIT_LIST_HEAD(&hctx->hctx_list);
3709 * Allocate space for all possible cpus to avoid allocation at
3712 hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
3717 if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
3718 gfp, node, false, false))
3722 spin_lock_init(&hctx->dispatch_wait_lock);
3723 init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
3724 INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
3726 hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
3730 blk_mq_hctx_kobj_init(hctx);
3735 sbitmap_free(&hctx->ctx_map);
3739 free_cpumask_var(hctx->cpumask);
3746 static void blk_mq_init_cpu_queues(struct request_queue *q,
3747 unsigned int nr_hw_queues)
3749 struct blk_mq_tag_set *set = q->tag_set;
3752 for_each_possible_cpu(i) {
3753 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
3754 struct blk_mq_hw_ctx *hctx;
3758 spin_lock_init(&__ctx->lock);
3759 for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
3760 INIT_LIST_HEAD(&__ctx->rq_lists[k]);
3765 * Set local node, IFF we have more than one hw queue. If
3766 * not, we remain on the home node of the device
3768 for (j = 0; j < set->nr_maps; j++) {
3769 hctx = blk_mq_map_queue_type(q, j, i);
3770 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
3771 hctx->numa_node = cpu_to_node(i);
3776 struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3777 unsigned int hctx_idx,
3780 struct blk_mq_tags *tags;
3783 tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags);
3787 ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
3789 blk_mq_free_rq_map(tags);
3796 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3799 if (blk_mq_is_shared_tags(set->flags)) {
3800 set->tags[hctx_idx] = set->shared_tags;
3805 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
3808 return set->tags[hctx_idx];
3811 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3812 struct blk_mq_tags *tags,
3813 unsigned int hctx_idx)
3816 blk_mq_free_rqs(set, tags, hctx_idx);
3817 blk_mq_free_rq_map(tags);
3821 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3822 unsigned int hctx_idx)
3824 if (!blk_mq_is_shared_tags(set->flags))
3825 blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx);
3827 set->tags[hctx_idx] = NULL;
3830 static void blk_mq_map_swqueue(struct request_queue *q)
3832 unsigned int j, hctx_idx;
3834 struct blk_mq_hw_ctx *hctx;
3835 struct blk_mq_ctx *ctx;
3836 struct blk_mq_tag_set *set = q->tag_set;
3838 queue_for_each_hw_ctx(q, hctx, i) {
3839 cpumask_clear(hctx->cpumask);
3841 hctx->dispatch_from = NULL;
3845 * Map software to hardware queues.
3847 * If the cpu isn't present, the cpu is mapped to first hctx.
3849 for_each_possible_cpu(i) {
3851 ctx = per_cpu_ptr(q->queue_ctx, i);
3852 for (j = 0; j < set->nr_maps; j++) {
3853 if (!set->map[j].nr_queues) {
3854 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3855 HCTX_TYPE_DEFAULT, i);
3858 hctx_idx = set->map[j].mq_map[i];
3859 /* unmapped hw queue can be remapped after CPU topo changed */
3860 if (!set->tags[hctx_idx] &&
3861 !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
3863 * If tags initialization fail for some hctx,
3864 * that hctx won't be brought online. In this
3865 * case, remap the current ctx to hctx[0] which
3866 * is guaranteed to always have tags allocated
3868 set->map[j].mq_map[i] = 0;
3871 hctx = blk_mq_map_queue_type(q, j, i);
3872 ctx->hctxs[j] = hctx;
3874 * If the CPU is already set in the mask, then we've
3875 * mapped this one already. This can happen if
3876 * devices share queues across queue maps.
3878 if (cpumask_test_cpu(i, hctx->cpumask))
3881 cpumask_set_cpu(i, hctx->cpumask);
3883 ctx->index_hw[hctx->type] = hctx->nr_ctx;
3884 hctx->ctxs[hctx->nr_ctx++] = ctx;
3887 * If the nr_ctx type overflows, we have exceeded the
3888 * amount of sw queues we can support.
3890 BUG_ON(!hctx->nr_ctx);
3893 for (; j < HCTX_MAX_TYPES; j++)
3894 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3895 HCTX_TYPE_DEFAULT, i);
3898 queue_for_each_hw_ctx(q, hctx, i) {
3900 * If no software queues are mapped to this hardware queue,
3901 * disable it and free the request entries.
3903 if (!hctx->nr_ctx) {
3904 /* Never unmap queue 0. We need it as a
3905 * fallback in case of a new remap fails
3909 __blk_mq_free_map_and_rqs(set, i);
3915 hctx->tags = set->tags[i];
3916 WARN_ON(!hctx->tags);
3919 * Set the map size to the number of mapped software queues.
3920 * This is more accurate and more efficient than looping
3921 * over all possibly mapped software queues.
3923 sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
3926 * Initialize batch roundrobin counts
3928 hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
3929 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
3934 * Caller needs to ensure that we're either frozen/quiesced, or that
3935 * the queue isn't live yet.
3937 static void queue_set_hctx_shared(struct request_queue *q, bool shared)
3939 struct blk_mq_hw_ctx *hctx;
3942 queue_for_each_hw_ctx(q, hctx, i) {
3944 hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3946 blk_mq_tag_idle(hctx);
3947 hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3952 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
3955 struct request_queue *q;
3957 lockdep_assert_held(&set->tag_list_lock);
3959 list_for_each_entry(q, &set->tag_list, tag_set_list) {
3960 blk_mq_freeze_queue(q);
3961 queue_set_hctx_shared(q, shared);
3962 blk_mq_unfreeze_queue(q);
3966 static void blk_mq_del_queue_tag_set(struct request_queue *q)
3968 struct blk_mq_tag_set *set = q->tag_set;
3970 mutex_lock(&set->tag_list_lock);
3971 list_del(&q->tag_set_list);
3972 if (list_is_singular(&set->tag_list)) {
3973 /* just transitioned to unshared */
3974 set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3975 /* update existing queue */
3976 blk_mq_update_tag_set_shared(set, false);
3978 mutex_unlock(&set->tag_list_lock);
3979 INIT_LIST_HEAD(&q->tag_set_list);
3982 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
3983 struct request_queue *q)
3985 mutex_lock(&set->tag_list_lock);
3988 * Check to see if we're transitioning to shared (from 1 to 2 queues).
3990 if (!list_empty(&set->tag_list) &&
3991 !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
3992 set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3993 /* update existing queue */
3994 blk_mq_update_tag_set_shared(set, true);
3996 if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
3997 queue_set_hctx_shared(q, true);
3998 list_add_tail(&q->tag_set_list, &set->tag_list);
4000 mutex_unlock(&set->tag_list_lock);
4003 /* All allocations will be freed in release handler of q->mq_kobj */
4004 static int blk_mq_alloc_ctxs(struct request_queue *q)
4006 struct blk_mq_ctxs *ctxs;
4009 ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
4013 ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
4014 if (!ctxs->queue_ctx)
4017 for_each_possible_cpu(cpu) {
4018 struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
4022 q->mq_kobj = &ctxs->kobj;
4023 q->queue_ctx = ctxs->queue_ctx;
4032 * It is the actual release handler for mq, but we do it from
4033 * request queue's release handler for avoiding use-after-free
4034 * and headache because q->mq_kobj shouldn't have been introduced,
4035 * but we can't group ctx/kctx kobj without it.
4037 void blk_mq_release(struct request_queue *q)
4039 struct blk_mq_hw_ctx *hctx, *next;
4042 queue_for_each_hw_ctx(q, hctx, i)
4043 WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
4045 /* all hctx are in .unused_hctx_list now */
4046 list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
4047 list_del_init(&hctx->hctx_list);
4048 kobject_put(&hctx->kobj);
4051 xa_destroy(&q->hctx_table);
4054 * release .mq_kobj and sw queue's kobject now because
4055 * both share lifetime with request queue.
4057 blk_mq_sysfs_deinit(q);
4060 static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
4063 struct request_queue *q;
4066 q = blk_alloc_queue(set->numa_node);
4068 return ERR_PTR(-ENOMEM);
4069 q->queuedata = queuedata;
4070 ret = blk_mq_init_allocated_queue(set, q);
4073 return ERR_PTR(ret);
4078 struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
4080 return blk_mq_init_queue_data(set, NULL);
4082 EXPORT_SYMBOL(blk_mq_init_queue);
4085 * blk_mq_destroy_queue - shutdown a request queue
4086 * @q: request queue to shutdown
4088 * This shuts down a request queue allocated by blk_mq_init_queue(). All future
4089 * requests will be failed with -ENODEV. The caller is responsible for dropping
4090 * the reference from blk_mq_init_queue() by calling blk_put_queue().
4092 * Context: can sleep
4094 void blk_mq_destroy_queue(struct request_queue *q)
4096 WARN_ON_ONCE(!queue_is_mq(q));
4097 WARN_ON_ONCE(blk_queue_registered(q));
4101 blk_queue_flag_set(QUEUE_FLAG_DYING, q);
4102 blk_queue_start_drain(q);
4103 blk_mq_freeze_queue_wait(q);
4106 blk_mq_cancel_work_sync(q);
4107 blk_mq_exit_queue(q);
4109 EXPORT_SYMBOL(blk_mq_destroy_queue);
4111 struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
4112 struct lock_class_key *lkclass)
4114 struct request_queue *q;
4115 struct gendisk *disk;
4117 q = blk_mq_init_queue_data(set, queuedata);
4121 disk = __alloc_disk_node(q, set->numa_node, lkclass);
4123 blk_mq_destroy_queue(q);
4125 return ERR_PTR(-ENOMEM);
4127 set_bit(GD_OWNS_QUEUE, &disk->state);
4130 EXPORT_SYMBOL(__blk_mq_alloc_disk);
4132 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
4133 struct lock_class_key *lkclass)
4135 struct gendisk *disk;
4137 if (!blk_get_queue(q))
4139 disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass);
4144 EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue);
4146 static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
4147 struct blk_mq_tag_set *set, struct request_queue *q,
4148 int hctx_idx, int node)
4150 struct blk_mq_hw_ctx *hctx = NULL, *tmp;
4152 /* reuse dead hctx first */
4153 spin_lock(&q->unused_hctx_lock);
4154 list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
4155 if (tmp->numa_node == node) {
4161 list_del_init(&hctx->hctx_list);
4162 spin_unlock(&q->unused_hctx_lock);
4165 hctx = blk_mq_alloc_hctx(q, set, node);
4169 if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
4175 kobject_put(&hctx->kobj);
4180 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
4181 struct request_queue *q)
4183 struct blk_mq_hw_ctx *hctx;
4186 /* protect against switching io scheduler */
4187 mutex_lock(&q->sysfs_lock);
4188 for (i = 0; i < set->nr_hw_queues; i++) {
4190 int node = blk_mq_get_hctx_node(set, i);
4191 struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i);
4194 old_node = old_hctx->numa_node;
4195 blk_mq_exit_hctx(q, set, old_hctx, i);
4198 if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) {
4201 pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
4203 hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node);
4204 WARN_ON_ONCE(!hctx);
4208 * Increasing nr_hw_queues fails. Free the newly allocated
4209 * hctxs and keep the previous q->nr_hw_queues.
4211 if (i != set->nr_hw_queues) {
4212 j = q->nr_hw_queues;
4215 q->nr_hw_queues = set->nr_hw_queues;
4218 xa_for_each_start(&q->hctx_table, j, hctx, j)
4219 blk_mq_exit_hctx(q, set, hctx, j);
4220 mutex_unlock(&q->sysfs_lock);
4223 static void blk_mq_update_poll_flag(struct request_queue *q)
4225 struct blk_mq_tag_set *set = q->tag_set;
4227 if (set->nr_maps > HCTX_TYPE_POLL &&
4228 set->map[HCTX_TYPE_POLL].nr_queues)
4229 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
4231 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
4234 int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
4235 struct request_queue *q)
4237 /* mark the queue as mq asap */
4238 q->mq_ops = set->ops;
4240 if (blk_mq_alloc_ctxs(q))
4243 /* init q->mq_kobj and sw queues' kobjects */
4244 blk_mq_sysfs_init(q);
4246 INIT_LIST_HEAD(&q->unused_hctx_list);
4247 spin_lock_init(&q->unused_hctx_lock);
4249 xa_init(&q->hctx_table);
4251 blk_mq_realloc_hw_ctxs(set, q);
4252 if (!q->nr_hw_queues)
4255 INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
4256 blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
4260 q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
4261 blk_mq_update_poll_flag(q);
4263 INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
4264 INIT_LIST_HEAD(&q->flush_list);
4265 INIT_LIST_HEAD(&q->requeue_list);
4266 spin_lock_init(&q->requeue_lock);
4268 q->nr_requests = set->queue_depth;
4270 blk_mq_init_cpu_queues(q, set->nr_hw_queues);
4271 blk_mq_add_queue_tag_set(set, q);
4272 blk_mq_map_swqueue(q);
4281 EXPORT_SYMBOL(blk_mq_init_allocated_queue);
4283 /* tags can _not_ be used after returning from blk_mq_exit_queue */
4284 void blk_mq_exit_queue(struct request_queue *q)
4286 struct blk_mq_tag_set *set = q->tag_set;
4288 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
4289 blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
4290 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
4291 blk_mq_del_queue_tag_set(q);
4294 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
4298 if (blk_mq_is_shared_tags(set->flags)) {
4299 set->shared_tags = blk_mq_alloc_map_and_rqs(set,
4302 if (!set->shared_tags)
4306 for (i = 0; i < set->nr_hw_queues; i++) {
4307 if (!__blk_mq_alloc_map_and_rqs(set, i))
4316 __blk_mq_free_map_and_rqs(set, i);
4318 if (blk_mq_is_shared_tags(set->flags)) {
4319 blk_mq_free_map_and_rqs(set, set->shared_tags,
4320 BLK_MQ_NO_HCTX_IDX);
4327 * Allocate the request maps associated with this tag_set. Note that this
4328 * may reduce the depth asked for, if memory is tight. set->queue_depth
4329 * will be updated to reflect the allocated depth.
4331 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
4336 depth = set->queue_depth;
4338 err = __blk_mq_alloc_rq_maps(set);
4342 set->queue_depth >>= 1;
4343 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
4347 } while (set->queue_depth);
4349 if (!set->queue_depth || err) {
4350 pr_err("blk-mq: failed to allocate request map\n");
4354 if (depth != set->queue_depth)
4355 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
4356 depth, set->queue_depth);
4361 static void blk_mq_update_queue_map(struct blk_mq_tag_set *set)
4364 * blk_mq_map_queues() and multiple .map_queues() implementations
4365 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
4366 * number of hardware queues.
4368 if (set->nr_maps == 1)
4369 set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
4371 if (set->ops->map_queues && !is_kdump_kernel()) {
4375 * transport .map_queues is usually done in the following
4378 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
4379 * mask = get_cpu_mask(queue)
4380 * for_each_cpu(cpu, mask)
4381 * set->map[x].mq_map[cpu] = queue;
4384 * When we need to remap, the table has to be cleared for
4385 * killing stale mapping since one CPU may not be mapped
4388 for (i = 0; i < set->nr_maps; i++)
4389 blk_mq_clear_mq_map(&set->map[i]);
4391 set->ops->map_queues(set);
4393 BUG_ON(set->nr_maps > 1);
4394 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
4398 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
4399 int new_nr_hw_queues)
4401 struct blk_mq_tags **new_tags;
4404 if (set->nr_hw_queues >= new_nr_hw_queues)
4407 new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
4408 GFP_KERNEL, set->numa_node);
4413 memcpy(new_tags, set->tags, set->nr_hw_queues *
4414 sizeof(*set->tags));
4416 set->tags = new_tags;
4418 for (i = set->nr_hw_queues; i < new_nr_hw_queues; i++) {
4419 if (!__blk_mq_alloc_map_and_rqs(set, i)) {
4420 while (--i >= set->nr_hw_queues)
4421 __blk_mq_free_map_and_rqs(set, i);
4428 set->nr_hw_queues = new_nr_hw_queues;
4433 * Alloc a tag set to be associated with one or more request queues.
4434 * May fail with EINVAL for various error conditions. May adjust the
4435 * requested depth down, if it's too large. In that case, the set
4436 * value will be stored in set->queue_depth.
4438 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
4442 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
4444 if (!set->nr_hw_queues)
4446 if (!set->queue_depth)
4448 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
4451 if (!set->ops->queue_rq)
4454 if (!set->ops->get_budget ^ !set->ops->put_budget)
4457 if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
4458 pr_info("blk-mq: reduced tag depth to %u\n",
4460 set->queue_depth = BLK_MQ_MAX_DEPTH;
4465 else if (set->nr_maps > HCTX_MAX_TYPES)
4469 * If a crashdump is active, then we are potentially in a very
4470 * memory constrained environment. Limit us to 1 queue and
4471 * 64 tags to prevent using too much memory.
4473 if (is_kdump_kernel()) {
4474 set->nr_hw_queues = 1;
4476 set->queue_depth = min(64U, set->queue_depth);
4479 * There is no use for more h/w queues than cpus if we just have
4482 if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
4483 set->nr_hw_queues = nr_cpu_ids;
4485 if (set->flags & BLK_MQ_F_BLOCKING) {
4486 set->srcu = kmalloc(sizeof(*set->srcu), GFP_KERNEL);
4489 ret = init_srcu_struct(set->srcu);
4495 set->tags = kcalloc_node(set->nr_hw_queues,
4496 sizeof(struct blk_mq_tags *), GFP_KERNEL,
4499 goto out_cleanup_srcu;
4501 for (i = 0; i < set->nr_maps; i++) {
4502 set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
4503 sizeof(set->map[i].mq_map[0]),
4504 GFP_KERNEL, set->numa_node);
4505 if (!set->map[i].mq_map)
4506 goto out_free_mq_map;
4507 set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues;
4510 blk_mq_update_queue_map(set);
4512 ret = blk_mq_alloc_set_map_and_rqs(set);
4514 goto out_free_mq_map;
4516 mutex_init(&set->tag_list_lock);
4517 INIT_LIST_HEAD(&set->tag_list);
4522 for (i = 0; i < set->nr_maps; i++) {
4523 kfree(set->map[i].mq_map);
4524 set->map[i].mq_map = NULL;
4529 if (set->flags & BLK_MQ_F_BLOCKING)
4530 cleanup_srcu_struct(set->srcu);
4532 if (set->flags & BLK_MQ_F_BLOCKING)
4536 EXPORT_SYMBOL(blk_mq_alloc_tag_set);
4538 /* allocate and initialize a tagset for a simple single-queue device */
4539 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set,
4540 const struct blk_mq_ops *ops, unsigned int queue_depth,
4541 unsigned int set_flags)
4543 memset(set, 0, sizeof(*set));
4545 set->nr_hw_queues = 1;
4547 set->queue_depth = queue_depth;
4548 set->numa_node = NUMA_NO_NODE;
4549 set->flags = set_flags;
4550 return blk_mq_alloc_tag_set(set);
4552 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set);
4554 void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
4558 for (i = 0; i < set->nr_hw_queues; i++)
4559 __blk_mq_free_map_and_rqs(set, i);
4561 if (blk_mq_is_shared_tags(set->flags)) {
4562 blk_mq_free_map_and_rqs(set, set->shared_tags,
4563 BLK_MQ_NO_HCTX_IDX);
4566 for (j = 0; j < set->nr_maps; j++) {
4567 kfree(set->map[j].mq_map);
4568 set->map[j].mq_map = NULL;
4573 if (set->flags & BLK_MQ_F_BLOCKING) {
4574 cleanup_srcu_struct(set->srcu);
4578 EXPORT_SYMBOL(blk_mq_free_tag_set);
4580 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
4582 struct blk_mq_tag_set *set = q->tag_set;
4583 struct blk_mq_hw_ctx *hctx;
4590 if (q->nr_requests == nr)
4593 blk_mq_freeze_queue(q);
4594 blk_mq_quiesce_queue(q);
4597 queue_for_each_hw_ctx(q, hctx, i) {
4601 * If we're using an MQ scheduler, just update the scheduler
4602 * queue depth. This is similar to what the old code would do.
4604 if (hctx->sched_tags) {
4605 ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
4608 ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
4613 if (q->elevator && q->elevator->type->ops.depth_updated)
4614 q->elevator->type->ops.depth_updated(hctx);
4617 q->nr_requests = nr;
4618 if (blk_mq_is_shared_tags(set->flags)) {
4620 blk_mq_tag_update_sched_shared_tags(q);
4622 blk_mq_tag_resize_shared_tags(set, nr);
4626 blk_mq_unquiesce_queue(q);
4627 blk_mq_unfreeze_queue(q);
4633 * request_queue and elevator_type pair.
4634 * It is just used by __blk_mq_update_nr_hw_queues to cache
4635 * the elevator_type associated with a request_queue.
4637 struct blk_mq_qe_pair {
4638 struct list_head node;
4639 struct request_queue *q;
4640 struct elevator_type *type;
4644 * Cache the elevator_type in qe pair list and switch the
4645 * io scheduler to 'none'
4647 static bool blk_mq_elv_switch_none(struct list_head *head,
4648 struct request_queue *q)
4650 struct blk_mq_qe_pair *qe;
4652 qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
4656 /* q->elevator needs protection from ->sysfs_lock */
4657 mutex_lock(&q->sysfs_lock);
4659 /* the check has to be done with holding sysfs_lock */
4665 INIT_LIST_HEAD(&qe->node);
4667 qe->type = q->elevator->type;
4668 /* keep a reference to the elevator module as we'll switch back */
4669 __elevator_get(qe->type);
4670 list_add(&qe->node, head);
4671 elevator_disable(q);
4673 mutex_unlock(&q->sysfs_lock);
4678 static struct blk_mq_qe_pair *blk_lookup_qe_pair(struct list_head *head,
4679 struct request_queue *q)
4681 struct blk_mq_qe_pair *qe;
4683 list_for_each_entry(qe, head, node)
4690 static void blk_mq_elv_switch_back(struct list_head *head,
4691 struct request_queue *q)
4693 struct blk_mq_qe_pair *qe;
4694 struct elevator_type *t;
4696 qe = blk_lookup_qe_pair(head, q);
4700 list_del(&qe->node);
4703 mutex_lock(&q->sysfs_lock);
4704 elevator_switch(q, t);
4705 /* drop the reference acquired in blk_mq_elv_switch_none */
4707 mutex_unlock(&q->sysfs_lock);
4710 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
4713 struct request_queue *q;
4715 int prev_nr_hw_queues = set->nr_hw_queues;
4718 lockdep_assert_held(&set->tag_list_lock);
4720 if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
4721 nr_hw_queues = nr_cpu_ids;
4722 if (nr_hw_queues < 1)
4724 if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
4727 list_for_each_entry(q, &set->tag_list, tag_set_list)
4728 blk_mq_freeze_queue(q);
4730 * Switch IO scheduler to 'none', cleaning up the data associated
4731 * with the previous scheduler. We will switch back once we are done
4732 * updating the new sw to hw queue mappings.
4734 list_for_each_entry(q, &set->tag_list, tag_set_list)
4735 if (!blk_mq_elv_switch_none(&head, q))
4738 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4739 blk_mq_debugfs_unregister_hctxs(q);
4740 blk_mq_sysfs_unregister_hctxs(q);
4743 if (blk_mq_realloc_tag_set_tags(set, nr_hw_queues) < 0)
4747 blk_mq_update_queue_map(set);
4748 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4749 blk_mq_realloc_hw_ctxs(set, q);
4750 blk_mq_update_poll_flag(q);
4751 if (q->nr_hw_queues != set->nr_hw_queues) {
4752 int i = prev_nr_hw_queues;
4754 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4755 nr_hw_queues, prev_nr_hw_queues);
4756 for (; i < set->nr_hw_queues; i++)
4757 __blk_mq_free_map_and_rqs(set, i);
4759 set->nr_hw_queues = prev_nr_hw_queues;
4762 blk_mq_map_swqueue(q);
4766 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4767 blk_mq_sysfs_register_hctxs(q);
4768 blk_mq_debugfs_register_hctxs(q);
4772 list_for_each_entry(q, &set->tag_list, tag_set_list)
4773 blk_mq_elv_switch_back(&head, q);
4775 list_for_each_entry(q, &set->tag_list, tag_set_list)
4776 blk_mq_unfreeze_queue(q);
4778 /* Free the excess tags when nr_hw_queues shrink. */
4779 for (i = set->nr_hw_queues; i < prev_nr_hw_queues; i++)
4780 __blk_mq_free_map_and_rqs(set, i);
4783 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
4785 mutex_lock(&set->tag_list_lock);
4786 __blk_mq_update_nr_hw_queues(set, nr_hw_queues);
4787 mutex_unlock(&set->tag_list_lock);
4789 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
4791 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
4792 struct io_comp_batch *iob, unsigned int flags)
4794 long state = get_current_state();
4798 ret = q->mq_ops->poll(hctx, iob);
4800 __set_current_state(TASK_RUNNING);
4804 if (signal_pending_state(state, current))
4805 __set_current_state(TASK_RUNNING);
4806 if (task_is_running(current))
4809 if (ret < 0 || (flags & BLK_POLL_ONESHOT))
4812 } while (!need_resched());
4814 __set_current_state(TASK_RUNNING);
4818 int blk_mq_poll(struct request_queue *q, blk_qc_t cookie,
4819 struct io_comp_batch *iob, unsigned int flags)
4821 struct blk_mq_hw_ctx *hctx = xa_load(&q->hctx_table, cookie);
4823 return blk_hctx_poll(q, hctx, iob, flags);
4826 int blk_rq_poll(struct request *rq, struct io_comp_batch *iob,
4827 unsigned int poll_flags)
4829 struct request_queue *q = rq->q;
4832 if (!blk_rq_is_poll(rq))
4834 if (!percpu_ref_tryget(&q->q_usage_counter))
4837 ret = blk_hctx_poll(q, rq->mq_hctx, iob, poll_flags);
4842 EXPORT_SYMBOL_GPL(blk_rq_poll);
4844 unsigned int blk_mq_rq_cpu(struct request *rq)
4846 return rq->mq_ctx->cpu;
4848 EXPORT_SYMBOL(blk_mq_rq_cpu);
4850 void blk_mq_cancel_work_sync(struct request_queue *q)
4852 struct blk_mq_hw_ctx *hctx;
4855 cancel_delayed_work_sync(&q->requeue_work);
4857 queue_for_each_hw_ctx(q, hctx, i)
4858 cancel_delayed_work_sync(&hctx->run_work);
4861 static int __init blk_mq_init(void)
4865 for_each_possible_cpu(i)
4866 init_llist_head(&per_cpu(blk_cpu_done, i));
4867 for_each_possible_cpu(i)
4868 INIT_CSD(&per_cpu(blk_cpu_csd, i),
4869 __blk_mq_complete_request_remote, NULL);
4870 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
4872 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
4873 "block/softirq:dead", NULL,
4874 blk_softirq_cpu_dead);
4875 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
4876 blk_mq_hctx_notify_dead);
4877 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
4878 blk_mq_hctx_notify_online,
4879 blk_mq_hctx_notify_offline);
4882 subsys_initcall(blk_mq_init);