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.
775 * For such case, force the completed nbytes to be equal to
776 * the BIO size so that bio_advance() sets the BIO remaining
777 * size to 0 and we end up calling bio_endio() before returning.
779 if (bio->bi_iter.bi_size != nbytes) {
780 bio->bi_status = BLK_STS_IOERR;
781 nbytes = bio->bi_iter.bi_size;
783 bio->bi_iter.bi_sector = rq->__sector;
787 bio_advance(bio, nbytes);
789 if (unlikely(rq->rq_flags & RQF_QUIET))
790 bio_set_flag(bio, BIO_QUIET);
791 /* don't actually finish bio if it's part of flush sequence */
792 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
796 static void blk_account_io_completion(struct request *req, unsigned int bytes)
798 if (req->part && blk_do_io_stat(req)) {
799 const int sgrp = op_stat_group(req_op(req));
802 part_stat_add(req->part, sectors[sgrp], bytes >> 9);
807 static void blk_print_req_error(struct request *req, blk_status_t status)
809 printk_ratelimited(KERN_ERR
810 "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
811 "phys_seg %u prio class %u\n",
812 blk_status_to_str(status),
813 req->q->disk ? req->q->disk->disk_name : "?",
814 blk_rq_pos(req), (__force u32)req_op(req),
815 blk_op_str(req_op(req)),
816 (__force u32)(req->cmd_flags & ~REQ_OP_MASK),
817 req->nr_phys_segments,
818 IOPRIO_PRIO_CLASS(req->ioprio));
822 * Fully end IO on a request. Does not support partial completions, or
825 static void blk_complete_request(struct request *req)
827 const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0;
828 int total_bytes = blk_rq_bytes(req);
829 struct bio *bio = req->bio;
831 trace_block_rq_complete(req, BLK_STS_OK, total_bytes);
836 #ifdef CONFIG_BLK_DEV_INTEGRITY
837 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ)
838 req->q->integrity.profile->complete_fn(req, total_bytes);
842 * Upper layers may call blk_crypto_evict_key() anytime after the last
843 * bio_endio(). Therefore, the keyslot must be released before that.
845 blk_crypto_rq_put_keyslot(req);
847 blk_account_io_completion(req, total_bytes);
850 struct bio *next = bio->bi_next;
852 /* Completion has already been traced */
853 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
855 if (req_op(req) == REQ_OP_ZONE_APPEND)
856 bio->bi_iter.bi_sector = req->__sector;
864 * Reset counters so that the request stacking driver
865 * can find how many bytes remain in the request
875 * blk_update_request - Complete multiple bytes without completing the request
876 * @req: the request being processed
877 * @error: block status code
878 * @nr_bytes: number of bytes to complete for @req
881 * Ends I/O on a number of bytes attached to @req, but doesn't complete
882 * the request structure even if @req doesn't have leftover.
883 * If @req has leftover, sets it up for the next range of segments.
885 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
886 * %false return from this function.
889 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
890 * except in the consistency check at the end of this function.
893 * %false - this request doesn't have any more data
894 * %true - this request has more data
896 bool blk_update_request(struct request *req, blk_status_t error,
897 unsigned int nr_bytes)
901 trace_block_rq_complete(req, error, nr_bytes);
906 #ifdef CONFIG_BLK_DEV_INTEGRITY
907 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
909 req->q->integrity.profile->complete_fn(req, nr_bytes);
913 * Upper layers may call blk_crypto_evict_key() anytime after the last
914 * bio_endio(). Therefore, the keyslot must be released before that.
916 if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req))
917 __blk_crypto_rq_put_keyslot(req);
919 if (unlikely(error && !blk_rq_is_passthrough(req) &&
920 !(req->rq_flags & RQF_QUIET)) &&
921 !test_bit(GD_DEAD, &req->q->disk->state)) {
922 blk_print_req_error(req, error);
923 trace_block_rq_error(req, error, nr_bytes);
926 blk_account_io_completion(req, nr_bytes);
930 struct bio *bio = req->bio;
931 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
933 if (bio_bytes == bio->bi_iter.bi_size)
934 req->bio = bio->bi_next;
936 /* Completion has already been traced */
937 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
938 req_bio_endio(req, bio, bio_bytes, error);
940 total_bytes += bio_bytes;
941 nr_bytes -= bio_bytes;
952 * Reset counters so that the request stacking driver
953 * can find how many bytes remain in the request
960 req->__data_len -= total_bytes;
962 /* update sector only for requests with clear definition of sector */
963 if (!blk_rq_is_passthrough(req))
964 req->__sector += total_bytes >> 9;
966 /* mixed attributes always follow the first bio */
967 if (req->rq_flags & RQF_MIXED_MERGE) {
968 req->cmd_flags &= ~REQ_FAILFAST_MASK;
969 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
972 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
974 * If total number of sectors is less than the first segment
975 * size, something has gone terribly wrong.
977 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
978 blk_dump_rq_flags(req, "request botched");
979 req->__data_len = blk_rq_cur_bytes(req);
982 /* recalculate the number of segments */
983 req->nr_phys_segments = blk_recalc_rq_segments(req);
988 EXPORT_SYMBOL_GPL(blk_update_request);
990 static inline void blk_account_io_done(struct request *req, u64 now)
992 trace_block_io_done(req);
995 * Account IO completion. flush_rq isn't accounted as a
996 * normal IO on queueing nor completion. Accounting the
997 * containing request is enough.
999 if (blk_do_io_stat(req) && req->part &&
1000 !(req->rq_flags & RQF_FLUSH_SEQ)) {
1001 const int sgrp = op_stat_group(req_op(req));
1004 update_io_ticks(req->part, jiffies, true);
1005 part_stat_inc(req->part, ios[sgrp]);
1006 part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
1011 static inline void blk_account_io_start(struct request *req)
1013 trace_block_io_start(req);
1015 if (blk_do_io_stat(req)) {
1017 * All non-passthrough requests are created from a bio with one
1018 * exception: when a flush command that is part of a flush sequence
1019 * generated by the state machine in blk-flush.c is cloned onto the
1020 * lower device by dm-multipath we can get here without a bio.
1023 req->part = req->bio->bi_bdev;
1025 req->part = req->q->disk->part0;
1028 update_io_ticks(req->part, jiffies, false);
1033 static inline void __blk_mq_end_request_acct(struct request *rq, u64 now)
1035 if (rq->rq_flags & RQF_STATS)
1036 blk_stat_add(rq, now);
1038 blk_mq_sched_completed_request(rq, now);
1039 blk_account_io_done(rq, now);
1042 inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
1044 if (blk_mq_need_time_stamp(rq))
1045 __blk_mq_end_request_acct(rq, ktime_get_ns());
1047 blk_mq_finish_request(rq);
1050 rq_qos_done(rq->q, rq);
1051 if (rq->end_io(rq, error) == RQ_END_IO_FREE)
1052 blk_mq_free_request(rq);
1054 blk_mq_free_request(rq);
1057 EXPORT_SYMBOL(__blk_mq_end_request);
1059 void blk_mq_end_request(struct request *rq, blk_status_t error)
1061 if (blk_update_request(rq, error, blk_rq_bytes(rq)))
1063 __blk_mq_end_request(rq, error);
1065 EXPORT_SYMBOL(blk_mq_end_request);
1067 #define TAG_COMP_BATCH 32
1069 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
1070 int *tag_array, int nr_tags)
1072 struct request_queue *q = hctx->queue;
1074 blk_mq_sub_active_requests(hctx, nr_tags);
1076 blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
1077 percpu_ref_put_many(&q->q_usage_counter, nr_tags);
1080 void blk_mq_end_request_batch(struct io_comp_batch *iob)
1082 int tags[TAG_COMP_BATCH], nr_tags = 0;
1083 struct blk_mq_hw_ctx *cur_hctx = NULL;
1088 now = ktime_get_ns();
1090 while ((rq = rq_list_pop(&iob->req_list)) != NULL) {
1092 prefetch(rq->rq_next);
1094 blk_complete_request(rq);
1096 __blk_mq_end_request_acct(rq, now);
1098 blk_mq_finish_request(rq);
1100 rq_qos_done(rq->q, rq);
1103 * If end_io handler returns NONE, then it still has
1104 * ownership of the request.
1106 if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
1109 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1110 if (!req_ref_put_and_test(rq))
1113 blk_crypto_free_request(rq);
1114 blk_pm_mark_last_busy(rq);
1116 if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) {
1118 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1120 cur_hctx = rq->mq_hctx;
1122 tags[nr_tags++] = rq->tag;
1126 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1128 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch);
1130 static void blk_complete_reqs(struct llist_head *list)
1132 struct llist_node *entry = llist_reverse_order(llist_del_all(list));
1133 struct request *rq, *next;
1135 llist_for_each_entry_safe(rq, next, entry, ipi_list)
1136 rq->q->mq_ops->complete(rq);
1139 static __latent_entropy void blk_done_softirq(struct softirq_action *h)
1141 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
1144 static int blk_softirq_cpu_dead(unsigned int cpu)
1146 blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
1150 static void __blk_mq_complete_request_remote(void *data)
1152 __raise_softirq_irqoff(BLOCK_SOFTIRQ);
1155 static inline bool blk_mq_complete_need_ipi(struct request *rq)
1157 int cpu = raw_smp_processor_id();
1159 if (!IS_ENABLED(CONFIG_SMP) ||
1160 !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
1163 * With force threaded interrupts enabled, raising softirq from an SMP
1164 * function call will always result in waking the ksoftirqd thread.
1165 * This is probably worse than completing the request on a different
1168 if (force_irqthreads())
1171 /* same CPU or cache domain? Complete locally */
1172 if (cpu == rq->mq_ctx->cpu ||
1173 (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
1174 cpus_share_cache(cpu, rq->mq_ctx->cpu)))
1177 /* don't try to IPI to an offline CPU */
1178 return cpu_online(rq->mq_ctx->cpu);
1181 static void blk_mq_complete_send_ipi(struct request *rq)
1185 cpu = rq->mq_ctx->cpu;
1186 if (llist_add(&rq->ipi_list, &per_cpu(blk_cpu_done, cpu)))
1187 smp_call_function_single_async(cpu, &per_cpu(blk_cpu_csd, cpu));
1190 static void blk_mq_raise_softirq(struct request *rq)
1192 struct llist_head *list;
1195 list = this_cpu_ptr(&blk_cpu_done);
1196 if (llist_add(&rq->ipi_list, list))
1197 raise_softirq(BLOCK_SOFTIRQ);
1201 bool blk_mq_complete_request_remote(struct request *rq)
1203 WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
1206 * For request which hctx has only one ctx mapping,
1207 * or a polled request, always complete locally,
1208 * it's pointless to redirect the completion.
1210 if ((rq->mq_hctx->nr_ctx == 1 &&
1211 rq->mq_ctx->cpu == raw_smp_processor_id()) ||
1212 rq->cmd_flags & REQ_POLLED)
1215 if (blk_mq_complete_need_ipi(rq)) {
1216 blk_mq_complete_send_ipi(rq);
1220 if (rq->q->nr_hw_queues == 1) {
1221 blk_mq_raise_softirq(rq);
1226 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
1229 * blk_mq_complete_request - end I/O on a request
1230 * @rq: the request being processed
1233 * Complete a request by scheduling the ->complete_rq operation.
1235 void blk_mq_complete_request(struct request *rq)
1237 if (!blk_mq_complete_request_remote(rq))
1238 rq->q->mq_ops->complete(rq);
1240 EXPORT_SYMBOL(blk_mq_complete_request);
1243 * blk_mq_start_request - Start processing a request
1244 * @rq: Pointer to request to be started
1246 * Function used by device drivers to notify the block layer that a request
1247 * is going to be processed now, so blk layer can do proper initializations
1248 * such as starting the timeout timer.
1250 void blk_mq_start_request(struct request *rq)
1252 struct request_queue *q = rq->q;
1254 trace_block_rq_issue(rq);
1256 if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags) &&
1257 !blk_rq_is_passthrough(rq)) {
1258 rq->io_start_time_ns = ktime_get_ns();
1259 rq->stats_sectors = blk_rq_sectors(rq);
1260 rq->rq_flags |= RQF_STATS;
1261 rq_qos_issue(q, rq);
1264 WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
1267 WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
1268 rq->mq_hctx->tags->rqs[rq->tag] = rq;
1270 #ifdef CONFIG_BLK_DEV_INTEGRITY
1271 if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
1272 q->integrity.profile->prepare_fn(rq);
1274 if (rq->bio && rq->bio->bi_opf & REQ_POLLED)
1275 WRITE_ONCE(rq->bio->bi_cookie, rq->mq_hctx->queue_num);
1277 EXPORT_SYMBOL(blk_mq_start_request);
1280 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
1281 * queues. This is important for md arrays to benefit from merging
1284 static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
1286 if (plug->multiple_queues)
1287 return BLK_MAX_REQUEST_COUNT * 2;
1288 return BLK_MAX_REQUEST_COUNT;
1291 static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
1293 struct request *last = rq_list_peek(&plug->mq_list);
1295 if (!plug->rq_count) {
1296 trace_block_plug(rq->q);
1297 } else if (plug->rq_count >= blk_plug_max_rq_count(plug) ||
1298 (!blk_queue_nomerges(rq->q) &&
1299 blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
1300 blk_mq_flush_plug_list(plug, false);
1302 trace_block_plug(rq->q);
1305 if (!plug->multiple_queues && last && last->q != rq->q)
1306 plug->multiple_queues = true;
1308 * Any request allocated from sched tags can't be issued to
1309 * ->queue_rqs() directly
1311 if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS))
1312 plug->has_elevator = true;
1314 rq_list_add(&plug->mq_list, rq);
1319 * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
1320 * @rq: request to insert
1321 * @at_head: insert request at head or tail of queue
1324 * Insert a fully prepared request at the back of the I/O scheduler queue
1325 * for execution. Don't wait for completion.
1328 * This function will invoke @done directly if the queue is dead.
1330 void blk_execute_rq_nowait(struct request *rq, bool at_head)
1332 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1334 WARN_ON(irqs_disabled());
1335 WARN_ON(!blk_rq_is_passthrough(rq));
1337 blk_account_io_start(rq);
1340 * As plugging can be enabled for passthrough requests on a zoned
1341 * device, directly accessing the plug instead of using blk_mq_plug()
1342 * should not have any consequences.
1344 if (current->plug && !at_head) {
1345 blk_add_rq_to_plug(current->plug, rq);
1349 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1350 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
1352 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
1354 struct blk_rq_wait {
1355 struct completion done;
1359 static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret)
1361 struct blk_rq_wait *wait = rq->end_io_data;
1364 complete(&wait->done);
1365 return RQ_END_IO_NONE;
1368 bool blk_rq_is_poll(struct request *rq)
1372 if (rq->mq_hctx->type != HCTX_TYPE_POLL)
1376 EXPORT_SYMBOL_GPL(blk_rq_is_poll);
1378 static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
1381 blk_hctx_poll(rq->q, rq->mq_hctx, NULL, 0);
1383 } while (!completion_done(wait));
1387 * blk_execute_rq - insert a request into queue for execution
1388 * @rq: request to insert
1389 * @at_head: insert request at head or tail of queue
1392 * Insert a fully prepared request at the back of the I/O scheduler queue
1393 * for execution and wait for completion.
1394 * Return: The blk_status_t result provided to blk_mq_end_request().
1396 blk_status_t blk_execute_rq(struct request *rq, bool at_head)
1398 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1399 struct blk_rq_wait wait = {
1400 .done = COMPLETION_INITIALIZER_ONSTACK(wait.done),
1403 WARN_ON(irqs_disabled());
1404 WARN_ON(!blk_rq_is_passthrough(rq));
1406 rq->end_io_data = &wait;
1407 rq->end_io = blk_end_sync_rq;
1409 blk_account_io_start(rq);
1410 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1411 blk_mq_run_hw_queue(hctx, false);
1413 if (blk_rq_is_poll(rq)) {
1414 blk_rq_poll_completion(rq, &wait.done);
1417 * Prevent hang_check timer from firing at us during very long
1420 unsigned long hang_check = sysctl_hung_task_timeout_secs;
1423 while (!wait_for_completion_io_timeout(&wait.done,
1424 hang_check * (HZ/2)))
1427 wait_for_completion_io(&wait.done);
1432 EXPORT_SYMBOL(blk_execute_rq);
1434 static void __blk_mq_requeue_request(struct request *rq)
1436 struct request_queue *q = rq->q;
1438 blk_mq_put_driver_tag(rq);
1440 trace_block_rq_requeue(rq);
1441 rq_qos_requeue(q, rq);
1443 if (blk_mq_request_started(rq)) {
1444 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1445 rq->rq_flags &= ~RQF_TIMED_OUT;
1449 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
1451 struct request_queue *q = rq->q;
1452 unsigned long flags;
1454 __blk_mq_requeue_request(rq);
1456 /* this request will be re-inserted to io scheduler queue */
1457 blk_mq_sched_requeue_request(rq);
1459 spin_lock_irqsave(&q->requeue_lock, flags);
1460 list_add_tail(&rq->queuelist, &q->requeue_list);
1461 spin_unlock_irqrestore(&q->requeue_lock, flags);
1463 if (kick_requeue_list)
1464 blk_mq_kick_requeue_list(q);
1466 EXPORT_SYMBOL(blk_mq_requeue_request);
1468 static void blk_mq_requeue_work(struct work_struct *work)
1470 struct request_queue *q =
1471 container_of(work, struct request_queue, requeue_work.work);
1473 LIST_HEAD(flush_list);
1476 spin_lock_irq(&q->requeue_lock);
1477 list_splice_init(&q->requeue_list, &rq_list);
1478 list_splice_init(&q->flush_list, &flush_list);
1479 spin_unlock_irq(&q->requeue_lock);
1481 while (!list_empty(&rq_list)) {
1482 rq = list_entry(rq_list.next, struct request, queuelist);
1484 * If RQF_DONTPREP ist set, the request has been started by the
1485 * driver already and might have driver-specific data allocated
1486 * already. Insert it into the hctx dispatch list to avoid
1487 * block layer merges for the request.
1489 if (rq->rq_flags & RQF_DONTPREP) {
1490 list_del_init(&rq->queuelist);
1491 blk_mq_request_bypass_insert(rq, 0);
1493 list_del_init(&rq->queuelist);
1494 blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
1498 while (!list_empty(&flush_list)) {
1499 rq = list_entry(flush_list.next, struct request, queuelist);
1500 list_del_init(&rq->queuelist);
1501 blk_mq_insert_request(rq, 0);
1504 blk_mq_run_hw_queues(q, false);
1507 void blk_mq_kick_requeue_list(struct request_queue *q)
1509 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
1511 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
1513 void blk_mq_delay_kick_requeue_list(struct request_queue *q,
1514 unsigned long msecs)
1516 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
1517 msecs_to_jiffies(msecs));
1519 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
1521 static bool blk_is_flush_data_rq(struct request *rq)
1523 return (rq->rq_flags & RQF_FLUSH_SEQ) && !is_flush_rq(rq);
1526 static bool blk_mq_rq_inflight(struct request *rq, void *priv)
1529 * If we find a request that isn't idle we know the queue is busy
1530 * as it's checked in the iter.
1531 * Return false to stop the iteration.
1533 * In case of queue quiesce, if one flush data request is completed,
1534 * don't count it as inflight given the flush sequence is suspended,
1535 * and the original flush data request is invisible to driver, just
1536 * like other pending requests because of quiesce
1538 if (blk_mq_request_started(rq) && !(blk_queue_quiesced(rq->q) &&
1539 blk_is_flush_data_rq(rq) &&
1540 blk_mq_request_completed(rq))) {
1550 bool blk_mq_queue_inflight(struct request_queue *q)
1554 blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
1557 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
1559 static void blk_mq_rq_timed_out(struct request *req)
1561 req->rq_flags |= RQF_TIMED_OUT;
1562 if (req->q->mq_ops->timeout) {
1563 enum blk_eh_timer_return ret;
1565 ret = req->q->mq_ops->timeout(req);
1566 if (ret == BLK_EH_DONE)
1568 WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
1574 struct blk_expired_data {
1575 bool has_timedout_rq;
1577 unsigned long timeout_start;
1580 static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired)
1582 unsigned long deadline;
1584 if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
1586 if (rq->rq_flags & RQF_TIMED_OUT)
1589 deadline = READ_ONCE(rq->deadline);
1590 if (time_after_eq(expired->timeout_start, deadline))
1593 if (expired->next == 0)
1594 expired->next = deadline;
1595 else if (time_after(expired->next, deadline))
1596 expired->next = deadline;
1600 void blk_mq_put_rq_ref(struct request *rq)
1602 if (is_flush_rq(rq)) {
1603 if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
1604 blk_mq_free_request(rq);
1605 } else if (req_ref_put_and_test(rq)) {
1606 __blk_mq_free_request(rq);
1610 static bool blk_mq_check_expired(struct request *rq, void *priv)
1612 struct blk_expired_data *expired = priv;
1615 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1616 * be reallocated underneath the timeout handler's processing, then
1617 * the expire check is reliable. If the request is not expired, then
1618 * it was completed and reallocated as a new request after returning
1619 * from blk_mq_check_expired().
1621 if (blk_mq_req_expired(rq, expired)) {
1622 expired->has_timedout_rq = true;
1628 static bool blk_mq_handle_expired(struct request *rq, void *priv)
1630 struct blk_expired_data *expired = priv;
1632 if (blk_mq_req_expired(rq, expired))
1633 blk_mq_rq_timed_out(rq);
1637 static void blk_mq_timeout_work(struct work_struct *work)
1639 struct request_queue *q =
1640 container_of(work, struct request_queue, timeout_work);
1641 struct blk_expired_data expired = {
1642 .timeout_start = jiffies,
1644 struct blk_mq_hw_ctx *hctx;
1647 /* A deadlock might occur if a request is stuck requiring a
1648 * timeout at the same time a queue freeze is waiting
1649 * completion, since the timeout code would not be able to
1650 * acquire the queue reference here.
1652 * That's why we don't use blk_queue_enter here; instead, we use
1653 * percpu_ref_tryget directly, because we need to be able to
1654 * obtain a reference even in the short window between the queue
1655 * starting to freeze, by dropping the first reference in
1656 * blk_freeze_queue_start, and the moment the last request is
1657 * consumed, marked by the instant q_usage_counter reaches
1660 if (!percpu_ref_tryget(&q->q_usage_counter))
1663 /* check if there is any timed-out request */
1664 blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
1665 if (expired.has_timedout_rq) {
1667 * Before walking tags, we must ensure any submit started
1668 * before the current time has finished. Since the submit
1669 * uses srcu or rcu, wait for a synchronization point to
1670 * ensure all running submits have finished
1672 blk_mq_wait_quiesce_done(q->tag_set);
1675 blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired);
1678 if (expired.next != 0) {
1679 mod_timer(&q->timeout, expired.next);
1682 * Request timeouts are handled as a forward rolling timer. If
1683 * we end up here it means that no requests are pending and
1684 * also that no request has been pending for a while. Mark
1685 * each hctx as idle.
1687 queue_for_each_hw_ctx(q, hctx, i) {
1688 /* the hctx may be unmapped, so check it here */
1689 if (blk_mq_hw_queue_mapped(hctx))
1690 blk_mq_tag_idle(hctx);
1696 struct flush_busy_ctx_data {
1697 struct blk_mq_hw_ctx *hctx;
1698 struct list_head *list;
1701 static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
1703 struct flush_busy_ctx_data *flush_data = data;
1704 struct blk_mq_hw_ctx *hctx = flush_data->hctx;
1705 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1706 enum hctx_type type = hctx->type;
1708 spin_lock(&ctx->lock);
1709 list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
1710 sbitmap_clear_bit(sb, bitnr);
1711 spin_unlock(&ctx->lock);
1716 * Process software queues that have been marked busy, splicing them
1717 * to the for-dispatch
1719 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
1721 struct flush_busy_ctx_data data = {
1726 sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
1728 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
1730 struct dispatch_rq_data {
1731 struct blk_mq_hw_ctx *hctx;
1735 static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
1738 struct dispatch_rq_data *dispatch_data = data;
1739 struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
1740 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1741 enum hctx_type type = hctx->type;
1743 spin_lock(&ctx->lock);
1744 if (!list_empty(&ctx->rq_lists[type])) {
1745 dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
1746 list_del_init(&dispatch_data->rq->queuelist);
1747 if (list_empty(&ctx->rq_lists[type]))
1748 sbitmap_clear_bit(sb, bitnr);
1750 spin_unlock(&ctx->lock);
1752 return !dispatch_data->rq;
1755 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
1756 struct blk_mq_ctx *start)
1758 unsigned off = start ? start->index_hw[hctx->type] : 0;
1759 struct dispatch_rq_data data = {
1764 __sbitmap_for_each_set(&hctx->ctx_map, off,
1765 dispatch_rq_from_ctx, &data);
1770 bool __blk_mq_alloc_driver_tag(struct request *rq)
1772 struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
1773 unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
1776 blk_mq_tag_busy(rq->mq_hctx);
1778 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
1779 bt = &rq->mq_hctx->tags->breserved_tags;
1782 if (!hctx_may_queue(rq->mq_hctx, bt))
1786 tag = __sbitmap_queue_get(bt);
1787 if (tag == BLK_MQ_NO_TAG)
1790 rq->tag = tag + tag_offset;
1791 blk_mq_inc_active_requests(rq->mq_hctx);
1795 static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
1796 int flags, void *key)
1798 struct blk_mq_hw_ctx *hctx;
1800 hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
1802 spin_lock(&hctx->dispatch_wait_lock);
1803 if (!list_empty(&wait->entry)) {
1804 struct sbitmap_queue *sbq;
1806 list_del_init(&wait->entry);
1807 sbq = &hctx->tags->bitmap_tags;
1808 atomic_dec(&sbq->ws_active);
1810 spin_unlock(&hctx->dispatch_wait_lock);
1812 blk_mq_run_hw_queue(hctx, true);
1817 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1818 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1819 * restart. For both cases, take care to check the condition again after
1820 * marking us as waiting.
1822 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
1825 struct sbitmap_queue *sbq;
1826 struct wait_queue_head *wq;
1827 wait_queue_entry_t *wait;
1830 if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
1831 !(blk_mq_is_shared_tags(hctx->flags))) {
1832 blk_mq_sched_mark_restart_hctx(hctx);
1835 * It's possible that a tag was freed in the window between the
1836 * allocation failure and adding the hardware queue to the wait
1839 * Don't clear RESTART here, someone else could have set it.
1840 * At most this will cost an extra queue run.
1842 return blk_mq_get_driver_tag(rq);
1845 wait = &hctx->dispatch_wait;
1846 if (!list_empty_careful(&wait->entry))
1849 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag))
1850 sbq = &hctx->tags->breserved_tags;
1852 sbq = &hctx->tags->bitmap_tags;
1853 wq = &bt_wait_ptr(sbq, hctx)->wait;
1855 spin_lock_irq(&wq->lock);
1856 spin_lock(&hctx->dispatch_wait_lock);
1857 if (!list_empty(&wait->entry)) {
1858 spin_unlock(&hctx->dispatch_wait_lock);
1859 spin_unlock_irq(&wq->lock);
1863 atomic_inc(&sbq->ws_active);
1864 wait->flags &= ~WQ_FLAG_EXCLUSIVE;
1865 __add_wait_queue(wq, wait);
1868 * Add one explicit barrier since blk_mq_get_driver_tag() may
1869 * not imply barrier in case of failure.
1871 * Order adding us to wait queue and allocating driver tag.
1873 * The pair is the one implied in sbitmap_queue_wake_up() which
1874 * orders clearing sbitmap tag bits and waitqueue_active() in
1875 * __sbitmap_queue_wake_up(), since waitqueue_active() is lockless
1877 * Otherwise, re-order of adding wait queue and getting driver tag
1878 * may cause __sbitmap_queue_wake_up() to wake up nothing because
1879 * the waitqueue_active() may not observe us in wait queue.
1884 * It's possible that a tag was freed in the window between the
1885 * allocation failure and adding the hardware queue to the wait
1888 ret = blk_mq_get_driver_tag(rq);
1890 spin_unlock(&hctx->dispatch_wait_lock);
1891 spin_unlock_irq(&wq->lock);
1896 * We got a tag, remove ourselves from the wait queue to ensure
1897 * someone else gets the wakeup.
1899 list_del_init(&wait->entry);
1900 atomic_dec(&sbq->ws_active);
1901 spin_unlock(&hctx->dispatch_wait_lock);
1902 spin_unlock_irq(&wq->lock);
1907 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1908 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1910 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1911 * - EWMA is one simple way to compute running average value
1912 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1913 * - take 4 as factor for avoiding to get too small(0) result, and this
1914 * factor doesn't matter because EWMA decreases exponentially
1916 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
1920 ewma = hctx->dispatch_busy;
1925 ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
1927 ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
1928 ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
1930 hctx->dispatch_busy = ewma;
1933 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1935 static void blk_mq_handle_dev_resource(struct request *rq,
1936 struct list_head *list)
1938 list_add(&rq->queuelist, list);
1939 __blk_mq_requeue_request(rq);
1942 static void blk_mq_handle_zone_resource(struct request *rq,
1943 struct list_head *zone_list)
1946 * If we end up here it is because we cannot dispatch a request to a
1947 * specific zone due to LLD level zone-write locking or other zone
1948 * related resource not being available. In this case, set the request
1949 * aside in zone_list for retrying it later.
1951 list_add(&rq->queuelist, zone_list);
1952 __blk_mq_requeue_request(rq);
1955 enum prep_dispatch {
1957 PREP_DISPATCH_NO_TAG,
1958 PREP_DISPATCH_NO_BUDGET,
1961 static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
1964 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1965 int budget_token = -1;
1968 budget_token = blk_mq_get_dispatch_budget(rq->q);
1969 if (budget_token < 0) {
1970 blk_mq_put_driver_tag(rq);
1971 return PREP_DISPATCH_NO_BUDGET;
1973 blk_mq_set_rq_budget_token(rq, budget_token);
1976 if (!blk_mq_get_driver_tag(rq)) {
1978 * The initial allocation attempt failed, so we need to
1979 * rerun the hardware queue when a tag is freed. The
1980 * waitqueue takes care of that. If the queue is run
1981 * before we add this entry back on the dispatch list,
1982 * we'll re-run it below.
1984 if (!blk_mq_mark_tag_wait(hctx, rq)) {
1986 * All budgets not got from this function will be put
1987 * together during handling partial dispatch
1990 blk_mq_put_dispatch_budget(rq->q, budget_token);
1991 return PREP_DISPATCH_NO_TAG;
1995 return PREP_DISPATCH_OK;
1998 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1999 static void blk_mq_release_budgets(struct request_queue *q,
2000 struct list_head *list)
2004 list_for_each_entry(rq, list, queuelist) {
2005 int budget_token = blk_mq_get_rq_budget_token(rq);
2007 if (budget_token >= 0)
2008 blk_mq_put_dispatch_budget(q, budget_token);
2013 * blk_mq_commit_rqs will notify driver using bd->last that there is no
2014 * more requests. (See comment in struct blk_mq_ops for commit_rqs for
2016 * Attention, we should explicitly call this in unusual cases:
2017 * 1) did not queue everything initially scheduled to queue
2018 * 2) the last attempt to queue a request failed
2020 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued,
2023 if (hctx->queue->mq_ops->commit_rqs && queued) {
2024 trace_block_unplug(hctx->queue, queued, !from_schedule);
2025 hctx->queue->mq_ops->commit_rqs(hctx);
2030 * Returns true if we did some work AND can potentially do more.
2032 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
2033 unsigned int nr_budgets)
2035 enum prep_dispatch prep;
2036 struct request_queue *q = hctx->queue;
2039 blk_status_t ret = BLK_STS_OK;
2040 LIST_HEAD(zone_list);
2041 bool needs_resource = false;
2043 if (list_empty(list))
2047 * Now process all the entries, sending them to the driver.
2051 struct blk_mq_queue_data bd;
2053 rq = list_first_entry(list, struct request, queuelist);
2055 WARN_ON_ONCE(hctx != rq->mq_hctx);
2056 prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
2057 if (prep != PREP_DISPATCH_OK)
2060 list_del_init(&rq->queuelist);
2063 bd.last = list_empty(list);
2066 * once the request is queued to lld, no need to cover the
2071 ret = q->mq_ops->queue_rq(hctx, &bd);
2076 case BLK_STS_RESOURCE:
2077 needs_resource = true;
2079 case BLK_STS_DEV_RESOURCE:
2080 blk_mq_handle_dev_resource(rq, list);
2082 case BLK_STS_ZONE_RESOURCE:
2084 * Move the request to zone_list and keep going through
2085 * the dispatch list to find more requests the drive can
2088 blk_mq_handle_zone_resource(rq, &zone_list);
2089 needs_resource = true;
2092 blk_mq_end_request(rq, ret);
2094 } while (!list_empty(list));
2096 if (!list_empty(&zone_list))
2097 list_splice_tail_init(&zone_list, list);
2099 /* If we didn't flush the entire list, we could have told the driver
2100 * there was more coming, but that turned out to be a lie.
2102 if (!list_empty(list) || ret != BLK_STS_OK)
2103 blk_mq_commit_rqs(hctx, queued, false);
2106 * Any items that need requeuing? Stuff them into hctx->dispatch,
2107 * that is where we will continue on next queue run.
2109 if (!list_empty(list)) {
2111 /* For non-shared tags, the RESTART check will suffice */
2112 bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
2113 ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||
2114 blk_mq_is_shared_tags(hctx->flags));
2117 blk_mq_release_budgets(q, list);
2119 spin_lock(&hctx->lock);
2120 list_splice_tail_init(list, &hctx->dispatch);
2121 spin_unlock(&hctx->lock);
2124 * Order adding requests to hctx->dispatch and checking
2125 * SCHED_RESTART flag. The pair of this smp_mb() is the one
2126 * in blk_mq_sched_restart(). Avoid restart code path to
2127 * miss the new added requests to hctx->dispatch, meantime
2128 * SCHED_RESTART is observed here.
2133 * If SCHED_RESTART was set by the caller of this function and
2134 * it is no longer set that means that it was cleared by another
2135 * thread and hence that a queue rerun is needed.
2137 * If 'no_tag' is set, that means that we failed getting
2138 * a driver tag with an I/O scheduler attached. If our dispatch
2139 * waitqueue is no longer active, ensure that we run the queue
2140 * AFTER adding our entries back to the list.
2142 * If no I/O scheduler has been configured it is possible that
2143 * the hardware queue got stopped and restarted before requests
2144 * were pushed back onto the dispatch list. Rerun the queue to
2145 * avoid starvation. Notes:
2146 * - blk_mq_run_hw_queue() checks whether or not a queue has
2147 * been stopped before rerunning a queue.
2148 * - Some but not all block drivers stop a queue before
2149 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
2152 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
2153 * bit is set, run queue after a delay to avoid IO stalls
2154 * that could otherwise occur if the queue is idle. We'll do
2155 * similar if we couldn't get budget or couldn't lock a zone
2156 * and SCHED_RESTART is set.
2158 needs_restart = blk_mq_sched_needs_restart(hctx);
2159 if (prep == PREP_DISPATCH_NO_BUDGET)
2160 needs_resource = true;
2161 if (!needs_restart ||
2162 (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
2163 blk_mq_run_hw_queue(hctx, true);
2164 else if (needs_resource)
2165 blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
2167 blk_mq_update_dispatch_busy(hctx, true);
2171 blk_mq_update_dispatch_busy(hctx, false);
2175 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
2177 int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
2179 if (cpu >= nr_cpu_ids)
2180 cpu = cpumask_first(hctx->cpumask);
2185 * It'd be great if the workqueue API had a way to pass
2186 * in a mask and had some smarts for more clever placement.
2187 * For now we just round-robin here, switching for every
2188 * BLK_MQ_CPU_WORK_BATCH queued items.
2190 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
2193 int next_cpu = hctx->next_cpu;
2195 if (hctx->queue->nr_hw_queues == 1)
2196 return WORK_CPU_UNBOUND;
2198 if (--hctx->next_cpu_batch <= 0) {
2200 next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
2202 if (next_cpu >= nr_cpu_ids)
2203 next_cpu = blk_mq_first_mapped_cpu(hctx);
2204 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
2208 * Do unbound schedule if we can't find a online CPU for this hctx,
2209 * and it should only happen in the path of handling CPU DEAD.
2211 if (!cpu_online(next_cpu)) {
2218 * Make sure to re-select CPU next time once after CPUs
2219 * in hctx->cpumask become online again.
2221 hctx->next_cpu = next_cpu;
2222 hctx->next_cpu_batch = 1;
2223 return WORK_CPU_UNBOUND;
2226 hctx->next_cpu = next_cpu;
2231 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
2232 * @hctx: Pointer to the hardware queue to run.
2233 * @msecs: Milliseconds of delay to wait before running the queue.
2235 * Run a hardware queue asynchronously with a delay of @msecs.
2237 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
2239 if (unlikely(blk_mq_hctx_stopped(hctx)))
2241 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
2242 msecs_to_jiffies(msecs));
2244 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
2247 * blk_mq_run_hw_queue - Start to run a hardware queue.
2248 * @hctx: Pointer to the hardware queue to run.
2249 * @async: If we want to run the queue asynchronously.
2251 * Check if the request queue is not in a quiesced state and if there are
2252 * pending requests to be sent. If this is true, run the queue to send requests
2255 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2260 * We can't run the queue inline with interrupts disabled.
2262 WARN_ON_ONCE(!async && in_interrupt());
2264 might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING);
2267 * When queue is quiesced, we may be switching io scheduler, or
2268 * updating nr_hw_queues, or other things, and we can't run queue
2269 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
2271 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
2274 __blk_mq_run_dispatch_ops(hctx->queue, false,
2275 need_run = !blk_queue_quiesced(hctx->queue) &&
2276 blk_mq_hctx_has_pending(hctx));
2281 if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) {
2282 blk_mq_delay_run_hw_queue(hctx, 0);
2286 blk_mq_run_dispatch_ops(hctx->queue,
2287 blk_mq_sched_dispatch_requests(hctx));
2289 EXPORT_SYMBOL(blk_mq_run_hw_queue);
2292 * Return prefered queue to dispatch from (if any) for non-mq aware IO
2295 static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
2297 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
2299 * If the IO scheduler does not respect hardware queues when
2300 * dispatching, we just don't bother with multiple HW queues and
2301 * dispatch from hctx for the current CPU since running multiple queues
2302 * just causes lock contention inside the scheduler and pointless cache
2305 struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT];
2307 if (!blk_mq_hctx_stopped(hctx))
2313 * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
2314 * @q: Pointer to the request queue to run.
2315 * @async: If we want to run the queue asynchronously.
2317 void blk_mq_run_hw_queues(struct request_queue *q, bool async)
2319 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2323 if (blk_queue_sq_sched(q))
2324 sq_hctx = blk_mq_get_sq_hctx(q);
2325 queue_for_each_hw_ctx(q, hctx, i) {
2326 if (blk_mq_hctx_stopped(hctx))
2329 * Dispatch from this hctx either if there's no hctx preferred
2330 * by IO scheduler or if it has requests that bypass the
2333 if (!sq_hctx || sq_hctx == hctx ||
2334 !list_empty_careful(&hctx->dispatch))
2335 blk_mq_run_hw_queue(hctx, async);
2338 EXPORT_SYMBOL(blk_mq_run_hw_queues);
2341 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
2342 * @q: Pointer to the request queue to run.
2343 * @msecs: Milliseconds of delay to wait before running the queues.
2345 void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
2347 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2351 if (blk_queue_sq_sched(q))
2352 sq_hctx = blk_mq_get_sq_hctx(q);
2353 queue_for_each_hw_ctx(q, hctx, i) {
2354 if (blk_mq_hctx_stopped(hctx))
2357 * If there is already a run_work pending, leave the
2358 * pending delay untouched. Otherwise, a hctx can stall
2359 * if another hctx is re-delaying the other's work
2360 * before the work executes.
2362 if (delayed_work_pending(&hctx->run_work))
2365 * Dispatch from this hctx either if there's no hctx preferred
2366 * by IO scheduler or if it has requests that bypass the
2369 if (!sq_hctx || sq_hctx == hctx ||
2370 !list_empty_careful(&hctx->dispatch))
2371 blk_mq_delay_run_hw_queue(hctx, msecs);
2374 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
2377 * This function is often used for pausing .queue_rq() by driver when
2378 * there isn't enough resource or some conditions aren't satisfied, and
2379 * BLK_STS_RESOURCE is usually returned.
2381 * We do not guarantee that dispatch can be drained or blocked
2382 * after blk_mq_stop_hw_queue() returns. Please use
2383 * blk_mq_quiesce_queue() for that requirement.
2385 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
2387 cancel_delayed_work(&hctx->run_work);
2389 set_bit(BLK_MQ_S_STOPPED, &hctx->state);
2391 EXPORT_SYMBOL(blk_mq_stop_hw_queue);
2394 * This function is often used for pausing .queue_rq() by driver when
2395 * there isn't enough resource or some conditions aren't satisfied, and
2396 * BLK_STS_RESOURCE is usually returned.
2398 * We do not guarantee that dispatch can be drained or blocked
2399 * after blk_mq_stop_hw_queues() returns. Please use
2400 * blk_mq_quiesce_queue() for that requirement.
2402 void blk_mq_stop_hw_queues(struct request_queue *q)
2404 struct blk_mq_hw_ctx *hctx;
2407 queue_for_each_hw_ctx(q, hctx, i)
2408 blk_mq_stop_hw_queue(hctx);
2410 EXPORT_SYMBOL(blk_mq_stop_hw_queues);
2412 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
2414 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2416 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
2418 EXPORT_SYMBOL(blk_mq_start_hw_queue);
2420 void blk_mq_start_hw_queues(struct request_queue *q)
2422 struct blk_mq_hw_ctx *hctx;
2425 queue_for_each_hw_ctx(q, hctx, i)
2426 blk_mq_start_hw_queue(hctx);
2428 EXPORT_SYMBOL(blk_mq_start_hw_queues);
2430 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2432 if (!blk_mq_hctx_stopped(hctx))
2435 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2436 blk_mq_run_hw_queue(hctx, async);
2438 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
2440 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
2442 struct blk_mq_hw_ctx *hctx;
2445 queue_for_each_hw_ctx(q, hctx, i)
2446 blk_mq_start_stopped_hw_queue(hctx, async ||
2447 (hctx->flags & BLK_MQ_F_BLOCKING));
2449 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
2451 static void blk_mq_run_work_fn(struct work_struct *work)
2453 struct blk_mq_hw_ctx *hctx =
2454 container_of(work, struct blk_mq_hw_ctx, run_work.work);
2456 blk_mq_run_dispatch_ops(hctx->queue,
2457 blk_mq_sched_dispatch_requests(hctx));
2461 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2462 * @rq: Pointer to request to be inserted.
2463 * @flags: BLK_MQ_INSERT_*
2465 * Should only be used carefully, when the caller knows we want to
2466 * bypass a potential IO scheduler on the target device.
2468 static void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags)
2470 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2472 spin_lock(&hctx->lock);
2473 if (flags & BLK_MQ_INSERT_AT_HEAD)
2474 list_add(&rq->queuelist, &hctx->dispatch);
2476 list_add_tail(&rq->queuelist, &hctx->dispatch);
2477 spin_unlock(&hctx->lock);
2480 static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
2481 struct blk_mq_ctx *ctx, struct list_head *list,
2482 bool run_queue_async)
2485 enum hctx_type type = hctx->type;
2488 * Try to issue requests directly if the hw queue isn't busy to save an
2489 * extra enqueue & dequeue to the sw queue.
2491 if (!hctx->dispatch_busy && !run_queue_async) {
2492 blk_mq_run_dispatch_ops(hctx->queue,
2493 blk_mq_try_issue_list_directly(hctx, list));
2494 if (list_empty(list))
2499 * preemption doesn't flush plug list, so it's possible ctx->cpu is
2502 list_for_each_entry(rq, list, queuelist) {
2503 BUG_ON(rq->mq_ctx != ctx);
2504 trace_block_rq_insert(rq);
2505 if (rq->cmd_flags & REQ_NOWAIT)
2506 run_queue_async = true;
2509 spin_lock(&ctx->lock);
2510 list_splice_tail_init(list, &ctx->rq_lists[type]);
2511 blk_mq_hctx_mark_pending(hctx, ctx);
2512 spin_unlock(&ctx->lock);
2514 blk_mq_run_hw_queue(hctx, run_queue_async);
2517 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
2519 struct request_queue *q = rq->q;
2520 struct blk_mq_ctx *ctx = rq->mq_ctx;
2521 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2523 if (blk_rq_is_passthrough(rq)) {
2525 * Passthrough request have to be added to hctx->dispatch
2526 * directly. The device may be in a situation where it can't
2527 * handle FS request, and always returns BLK_STS_RESOURCE for
2528 * them, which gets them added to hctx->dispatch.
2530 * If a passthrough request is required to unblock the queues,
2531 * and it is added to the scheduler queue, there is no chance to
2532 * dispatch it given we prioritize requests in hctx->dispatch.
2534 blk_mq_request_bypass_insert(rq, flags);
2535 } else if (req_op(rq) == REQ_OP_FLUSH) {
2537 * Firstly normal IO request is inserted to scheduler queue or
2538 * sw queue, meantime we add flush request to dispatch queue(
2539 * hctx->dispatch) directly and there is at most one in-flight
2540 * flush request for each hw queue, so it doesn't matter to add
2541 * flush request to tail or front of the dispatch queue.
2543 * Secondly in case of NCQ, flush request belongs to non-NCQ
2544 * command, and queueing it will fail when there is any
2545 * in-flight normal IO request(NCQ command). When adding flush
2546 * rq to the front of hctx->dispatch, it is easier to introduce
2547 * extra time to flush rq's latency because of S_SCHED_RESTART
2548 * compared with adding to the tail of dispatch queue, then
2549 * chance of flush merge is increased, and less flush requests
2550 * will be issued to controller. It is observed that ~10% time
2551 * is saved in blktests block/004 on disk attached to AHCI/NCQ
2552 * drive when adding flush rq to the front of hctx->dispatch.
2554 * Simply queue flush rq to the front of hctx->dispatch so that
2555 * intensive flush workloads can benefit in case of NCQ HW.
2557 blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD);
2558 } else if (q->elevator) {
2561 WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG);
2563 list_add(&rq->queuelist, &list);
2564 q->elevator->type->ops.insert_requests(hctx, &list, flags);
2566 trace_block_rq_insert(rq);
2568 spin_lock(&ctx->lock);
2569 if (flags & BLK_MQ_INSERT_AT_HEAD)
2570 list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]);
2572 list_add_tail(&rq->queuelist,
2573 &ctx->rq_lists[hctx->type]);
2574 blk_mq_hctx_mark_pending(hctx, ctx);
2575 spin_unlock(&ctx->lock);
2579 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
2580 unsigned int nr_segs)
2584 if (bio->bi_opf & REQ_RAHEAD)
2585 rq->cmd_flags |= REQ_FAILFAST_MASK;
2587 rq->__sector = bio->bi_iter.bi_sector;
2588 blk_rq_bio_prep(rq, bio, nr_segs);
2590 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2591 err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
2594 blk_account_io_start(rq);
2597 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
2598 struct request *rq, bool last)
2600 struct request_queue *q = rq->q;
2601 struct blk_mq_queue_data bd = {
2608 * For OK queue, we are done. For error, caller may kill it.
2609 * Any other error (busy), just add it to our list as we
2610 * previously would have done.
2612 ret = q->mq_ops->queue_rq(hctx, &bd);
2615 blk_mq_update_dispatch_busy(hctx, false);
2617 case BLK_STS_RESOURCE:
2618 case BLK_STS_DEV_RESOURCE:
2619 blk_mq_update_dispatch_busy(hctx, true);
2620 __blk_mq_requeue_request(rq);
2623 blk_mq_update_dispatch_busy(hctx, false);
2630 static bool blk_mq_get_budget_and_tag(struct request *rq)
2634 budget_token = blk_mq_get_dispatch_budget(rq->q);
2635 if (budget_token < 0)
2637 blk_mq_set_rq_budget_token(rq, budget_token);
2638 if (!blk_mq_get_driver_tag(rq)) {
2639 blk_mq_put_dispatch_budget(rq->q, budget_token);
2646 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2647 * @hctx: Pointer of the associated hardware queue.
2648 * @rq: Pointer to request to be sent.
2650 * If the device has enough resources to accept a new request now, send the
2651 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2652 * we can try send it another time in the future. Requests inserted at this
2653 * queue have higher priority.
2655 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
2660 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2661 blk_mq_insert_request(rq, 0);
2665 if ((rq->rq_flags & RQF_USE_SCHED) || !blk_mq_get_budget_and_tag(rq)) {
2666 blk_mq_insert_request(rq, 0);
2667 blk_mq_run_hw_queue(hctx, rq->cmd_flags & REQ_NOWAIT);
2671 ret = __blk_mq_issue_directly(hctx, rq, true);
2675 case BLK_STS_RESOURCE:
2676 case BLK_STS_DEV_RESOURCE:
2677 blk_mq_request_bypass_insert(rq, 0);
2678 blk_mq_run_hw_queue(hctx, false);
2681 blk_mq_end_request(rq, ret);
2686 static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
2688 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2690 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2691 blk_mq_insert_request(rq, 0);
2695 if (!blk_mq_get_budget_and_tag(rq))
2696 return BLK_STS_RESOURCE;
2697 return __blk_mq_issue_directly(hctx, rq, last);
2700 static void blk_mq_plug_issue_direct(struct blk_plug *plug)
2702 struct blk_mq_hw_ctx *hctx = NULL;
2705 blk_status_t ret = BLK_STS_OK;
2707 while ((rq = rq_list_pop(&plug->mq_list))) {
2708 bool last = rq_list_empty(plug->mq_list);
2710 if (hctx != rq->mq_hctx) {
2712 blk_mq_commit_rqs(hctx, queued, false);
2718 ret = blk_mq_request_issue_directly(rq, last);
2723 case BLK_STS_RESOURCE:
2724 case BLK_STS_DEV_RESOURCE:
2725 blk_mq_request_bypass_insert(rq, 0);
2726 blk_mq_run_hw_queue(hctx, false);
2729 blk_mq_end_request(rq, ret);
2735 if (ret != BLK_STS_OK)
2736 blk_mq_commit_rqs(hctx, queued, false);
2739 static void __blk_mq_flush_plug_list(struct request_queue *q,
2740 struct blk_plug *plug)
2742 if (blk_queue_quiesced(q))
2744 q->mq_ops->queue_rqs(&plug->mq_list);
2747 static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
2749 struct blk_mq_hw_ctx *this_hctx = NULL;
2750 struct blk_mq_ctx *this_ctx = NULL;
2751 struct request *requeue_list = NULL;
2752 struct request **requeue_lastp = &requeue_list;
2753 unsigned int depth = 0;
2754 bool is_passthrough = false;
2758 struct request *rq = rq_list_pop(&plug->mq_list);
2761 this_hctx = rq->mq_hctx;
2762 this_ctx = rq->mq_ctx;
2763 is_passthrough = blk_rq_is_passthrough(rq);
2764 } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx ||
2765 is_passthrough != blk_rq_is_passthrough(rq)) {
2766 rq_list_add_tail(&requeue_lastp, rq);
2769 list_add(&rq->queuelist, &list);
2771 } while (!rq_list_empty(plug->mq_list));
2773 plug->mq_list = requeue_list;
2774 trace_block_unplug(this_hctx->queue, depth, !from_sched);
2776 percpu_ref_get(&this_hctx->queue->q_usage_counter);
2777 /* passthrough requests should never be issued to the I/O scheduler */
2778 if (is_passthrough) {
2779 spin_lock(&this_hctx->lock);
2780 list_splice_tail_init(&list, &this_hctx->dispatch);
2781 spin_unlock(&this_hctx->lock);
2782 blk_mq_run_hw_queue(this_hctx, from_sched);
2783 } else if (this_hctx->queue->elevator) {
2784 this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
2786 blk_mq_run_hw_queue(this_hctx, from_sched);
2788 blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched);
2790 percpu_ref_put(&this_hctx->queue->q_usage_counter);
2793 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
2798 * We may have been called recursively midway through handling
2799 * plug->mq_list via a schedule() in the driver's queue_rq() callback.
2800 * To avoid mq_list changing under our feet, clear rq_count early and
2801 * bail out specifically if rq_count is 0 rather than checking
2802 * whether the mq_list is empty.
2804 if (plug->rq_count == 0)
2808 if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
2809 struct request_queue *q;
2811 rq = rq_list_peek(&plug->mq_list);
2815 * Peek first request and see if we have a ->queue_rqs() hook.
2816 * If we do, we can dispatch the whole plug list in one go. We
2817 * already know at this point that all requests belong to the
2818 * same queue, caller must ensure that's the case.
2820 if (q->mq_ops->queue_rqs) {
2821 blk_mq_run_dispatch_ops(q,
2822 __blk_mq_flush_plug_list(q, plug));
2823 if (rq_list_empty(plug->mq_list))
2827 blk_mq_run_dispatch_ops(q,
2828 blk_mq_plug_issue_direct(plug));
2829 if (rq_list_empty(plug->mq_list))
2834 blk_mq_dispatch_plug_list(plug, from_schedule);
2835 } while (!rq_list_empty(plug->mq_list));
2838 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
2839 struct list_head *list)
2842 blk_status_t ret = BLK_STS_OK;
2844 while (!list_empty(list)) {
2845 struct request *rq = list_first_entry(list, struct request,
2848 list_del_init(&rq->queuelist);
2849 ret = blk_mq_request_issue_directly(rq, list_empty(list));
2854 case BLK_STS_RESOURCE:
2855 case BLK_STS_DEV_RESOURCE:
2856 blk_mq_request_bypass_insert(rq, 0);
2857 if (list_empty(list))
2858 blk_mq_run_hw_queue(hctx, false);
2861 blk_mq_end_request(rq, ret);
2867 if (ret != BLK_STS_OK)
2868 blk_mq_commit_rqs(hctx, queued, false);
2871 static bool blk_mq_attempt_bio_merge(struct request_queue *q,
2872 struct bio *bio, unsigned int nr_segs)
2874 if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
2875 if (blk_attempt_plug_merge(q, bio, nr_segs))
2877 if (blk_mq_sched_bio_merge(q, bio, nr_segs))
2883 static struct request *blk_mq_get_new_requests(struct request_queue *q,
2884 struct blk_plug *plug,
2888 struct blk_mq_alloc_data data = {
2891 .cmd_flags = bio->bi_opf,
2895 if (blk_mq_attempt_bio_merge(q, bio, nsegs))
2898 rq_qos_throttle(q, bio);
2901 data.nr_tags = plug->nr_ios;
2903 data.cached_rq = &plug->cached_rq;
2906 rq = __blk_mq_alloc_requests(&data);
2909 rq_qos_cleanup(q, bio);
2910 if (bio->bi_opf & REQ_NOWAIT)
2911 bio_wouldblock_error(bio);
2916 * Check if we can use the passed on request for submitting the passed in bio,
2917 * and remove it from the request list if it can be used.
2919 static bool blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug,
2922 enum hctx_type type = blk_mq_get_hctx_type(bio->bi_opf);
2923 enum hctx_type hctx_type = rq->mq_hctx->type;
2925 WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq);
2927 if (type != hctx_type &&
2928 !(type == HCTX_TYPE_READ && hctx_type == HCTX_TYPE_DEFAULT))
2930 if (op_is_flush(rq->cmd_flags) != op_is_flush(bio->bi_opf))
2934 * If any qos ->throttle() end up blocking, we will have flushed the
2935 * plug and hence killed the cached_rq list as well. Pop this entry
2936 * before we throttle.
2938 plug->cached_rq = rq_list_next(rq);
2939 rq_qos_throttle(rq->q, bio);
2941 blk_mq_rq_time_init(rq, 0);
2942 rq->cmd_flags = bio->bi_opf;
2943 INIT_LIST_HEAD(&rq->queuelist);
2947 static void bio_set_ioprio(struct bio *bio)
2949 /* Nobody set ioprio so far? Initialize it based on task's nice value */
2950 if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
2951 bio->bi_ioprio = get_current_ioprio();
2952 blkcg_set_ioprio(bio);
2956 * blk_mq_submit_bio - Create and send a request to block device.
2957 * @bio: Bio pointer.
2959 * Builds up a request structure from @q and @bio and send to the device. The
2960 * request may not be queued directly to hardware if:
2961 * * This request can be merged with another one
2962 * * We want to place request at plug queue for possible future merging
2963 * * There is an IO scheduler active at this queue
2965 * It will not queue the request if there is an error with the bio, or at the
2968 void blk_mq_submit_bio(struct bio *bio)
2970 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
2971 struct blk_plug *plug = blk_mq_plug(bio);
2972 const int is_sync = op_is_sync(bio->bi_opf);
2973 struct blk_mq_hw_ctx *hctx;
2974 struct request *rq = NULL;
2975 unsigned int nr_segs = 1;
2978 bio = blk_queue_bounce(bio, q);
2979 bio_set_ioprio(bio);
2982 rq = rq_list_peek(&plug->cached_rq);
2983 if (rq && rq->q != q)
2987 if (unlikely(bio_may_exceed_limits(bio, &q->limits))) {
2988 bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
2992 if (!bio_integrity_prep(bio))
2994 if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
2996 if (blk_mq_use_cached_rq(rq, plug, bio))
2998 percpu_ref_get(&q->q_usage_counter);
3000 if (unlikely(bio_queue_enter(bio)))
3002 if (unlikely(bio_may_exceed_limits(bio, &q->limits))) {
3003 bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
3007 if (!bio_integrity_prep(bio))
3011 rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
3012 if (unlikely(!rq)) {
3019 trace_block_getrq(bio);
3021 rq_qos_track(q, rq, bio);
3023 blk_mq_bio_to_request(rq, bio, nr_segs);
3025 ret = blk_crypto_rq_get_keyslot(rq);
3026 if (ret != BLK_STS_OK) {
3027 bio->bi_status = ret;
3029 blk_mq_free_request(rq);
3033 if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq))
3037 blk_add_rq_to_plug(plug, rq);
3042 if ((rq->rq_flags & RQF_USE_SCHED) ||
3043 (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) {
3044 blk_mq_insert_request(rq, 0);
3045 blk_mq_run_hw_queue(hctx, true);
3047 blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq));
3051 #ifdef CONFIG_BLK_MQ_STACKING
3053 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
3054 * @rq: the request being queued
3056 blk_status_t blk_insert_cloned_request(struct request *rq)
3058 struct request_queue *q = rq->q;
3059 unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
3060 unsigned int max_segments = blk_rq_get_max_segments(rq);
3063 if (blk_rq_sectors(rq) > max_sectors) {
3065 * SCSI device does not have a good way to return if
3066 * Write Same/Zero is actually supported. If a device rejects
3067 * a non-read/write command (discard, write same,etc.) the
3068 * low-level device driver will set the relevant queue limit to
3069 * 0 to prevent blk-lib from issuing more of the offending
3070 * operations. Commands queued prior to the queue limit being
3071 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
3072 * errors being propagated to upper layers.
3074 if (max_sectors == 0)
3075 return BLK_STS_NOTSUPP;
3077 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
3078 __func__, blk_rq_sectors(rq), max_sectors);
3079 return BLK_STS_IOERR;
3083 * The queue settings related to segment counting may differ from the
3086 rq->nr_phys_segments = blk_recalc_rq_segments(rq);
3087 if (rq->nr_phys_segments > max_segments) {
3088 printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n",
3089 __func__, rq->nr_phys_segments, max_segments);
3090 return BLK_STS_IOERR;
3093 if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq)))
3094 return BLK_STS_IOERR;
3096 ret = blk_crypto_rq_get_keyslot(rq);
3097 if (ret != BLK_STS_OK)
3100 blk_account_io_start(rq);
3103 * Since we have a scheduler attached on the top device,
3104 * bypass a potential scheduler on the bottom device for
3107 blk_mq_run_dispatch_ops(q,
3108 ret = blk_mq_request_issue_directly(rq, true));
3110 blk_account_io_done(rq, ktime_get_ns());
3113 EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
3116 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3117 * @rq: the clone request to be cleaned up
3120 * Free all bios in @rq for a cloned request.
3122 void blk_rq_unprep_clone(struct request *rq)
3126 while ((bio = rq->bio) != NULL) {
3127 rq->bio = bio->bi_next;
3132 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
3135 * blk_rq_prep_clone - Helper function to setup clone request
3136 * @rq: the request to be setup
3137 * @rq_src: original request to be cloned
3138 * @bs: bio_set that bios for clone are allocated from
3139 * @gfp_mask: memory allocation mask for bio
3140 * @bio_ctr: setup function to be called for each clone bio.
3141 * Returns %0 for success, non %0 for failure.
3142 * @data: private data to be passed to @bio_ctr
3145 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3146 * Also, pages which the original bios are pointing to are not copied
3147 * and the cloned bios just point same pages.
3148 * So cloned bios must be completed before original bios, which means
3149 * the caller must complete @rq before @rq_src.
3151 int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
3152 struct bio_set *bs, gfp_t gfp_mask,
3153 int (*bio_ctr)(struct bio *, struct bio *, void *),
3156 struct bio *bio, *bio_src;
3161 __rq_for_each_bio(bio_src, rq_src) {
3162 bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask,
3167 if (bio_ctr && bio_ctr(bio, bio_src, data))
3171 rq->biotail->bi_next = bio;
3174 rq->bio = rq->biotail = bio;
3179 /* Copy attributes of the original request to the clone request. */
3180 rq->__sector = blk_rq_pos(rq_src);
3181 rq->__data_len = blk_rq_bytes(rq_src);
3182 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
3183 rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
3184 rq->special_vec = rq_src->special_vec;
3186 rq->nr_phys_segments = rq_src->nr_phys_segments;
3187 rq->ioprio = rq_src->ioprio;
3189 if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
3197 blk_rq_unprep_clone(rq);
3201 EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3202 #endif /* CONFIG_BLK_MQ_STACKING */
3205 * Steal bios from a request and add them to a bio list.
3206 * The request must not have been partially completed before.
3208 void blk_steal_bios(struct bio_list *list, struct request *rq)
3212 list->tail->bi_next = rq->bio;
3214 list->head = rq->bio;
3215 list->tail = rq->biotail;
3223 EXPORT_SYMBOL_GPL(blk_steal_bios);
3225 static size_t order_to_size(unsigned int order)
3227 return (size_t)PAGE_SIZE << order;
3230 /* called before freeing request pool in @tags */
3231 static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
3232 struct blk_mq_tags *tags)
3235 unsigned long flags;
3238 * There is no need to clear mapping if driver tags is not initialized
3239 * or the mapping belongs to the driver tags.
3241 if (!drv_tags || drv_tags == tags)
3244 list_for_each_entry(page, &tags->page_list, lru) {
3245 unsigned long start = (unsigned long)page_address(page);
3246 unsigned long end = start + order_to_size(page->private);
3249 for (i = 0; i < drv_tags->nr_tags; i++) {
3250 struct request *rq = drv_tags->rqs[i];
3251 unsigned long rq_addr = (unsigned long)rq;
3253 if (rq_addr >= start && rq_addr < end) {
3254 WARN_ON_ONCE(req_ref_read(rq) != 0);
3255 cmpxchg(&drv_tags->rqs[i], rq, NULL);
3261 * Wait until all pending iteration is done.
3263 * Request reference is cleared and it is guaranteed to be observed
3264 * after the ->lock is released.
3266 spin_lock_irqsave(&drv_tags->lock, flags);
3267 spin_unlock_irqrestore(&drv_tags->lock, flags);
3270 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
3271 unsigned int hctx_idx)
3273 struct blk_mq_tags *drv_tags;
3276 if (list_empty(&tags->page_list))
3279 if (blk_mq_is_shared_tags(set->flags))
3280 drv_tags = set->shared_tags;
3282 drv_tags = set->tags[hctx_idx];
3284 if (tags->static_rqs && set->ops->exit_request) {
3287 for (i = 0; i < tags->nr_tags; i++) {
3288 struct request *rq = tags->static_rqs[i];
3292 set->ops->exit_request(set, rq, hctx_idx);
3293 tags->static_rqs[i] = NULL;
3297 blk_mq_clear_rq_mapping(drv_tags, tags);
3299 while (!list_empty(&tags->page_list)) {
3300 page = list_first_entry(&tags->page_list, struct page, lru);
3301 list_del_init(&page->lru);
3303 * Remove kmemleak object previously allocated in
3304 * blk_mq_alloc_rqs().
3306 kmemleak_free(page_address(page));
3307 __free_pages(page, page->private);
3311 void blk_mq_free_rq_map(struct blk_mq_tags *tags)
3315 kfree(tags->static_rqs);
3316 tags->static_rqs = NULL;
3318 blk_mq_free_tags(tags);
3321 static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set,
3322 unsigned int hctx_idx)
3326 for (i = 0; i < set->nr_maps; i++) {
3327 unsigned int start = set->map[i].queue_offset;
3328 unsigned int end = start + set->map[i].nr_queues;
3330 if (hctx_idx >= start && hctx_idx < end)
3334 if (i >= set->nr_maps)
3335 i = HCTX_TYPE_DEFAULT;
3340 static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set,
3341 unsigned int hctx_idx)
3343 enum hctx_type type = hctx_idx_to_type(set, hctx_idx);
3345 return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx);
3348 static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
3349 unsigned int hctx_idx,
3350 unsigned int nr_tags,
3351 unsigned int reserved_tags)
3353 int node = blk_mq_get_hctx_node(set, hctx_idx);
3354 struct blk_mq_tags *tags;
3356 if (node == NUMA_NO_NODE)
3357 node = set->numa_node;
3359 tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
3360 BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
3364 tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3365 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3370 tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3371 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3373 if (!tags->static_rqs)
3381 blk_mq_free_tags(tags);
3385 static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
3386 unsigned int hctx_idx, int node)
3390 if (set->ops->init_request) {
3391 ret = set->ops->init_request(set, rq, hctx_idx, node);
3396 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
3400 static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
3401 struct blk_mq_tags *tags,
3402 unsigned int hctx_idx, unsigned int depth)
3404 unsigned int i, j, entries_per_page, max_order = 4;
3405 int node = blk_mq_get_hctx_node(set, hctx_idx);
3406 size_t rq_size, left;
3408 if (node == NUMA_NO_NODE)
3409 node = set->numa_node;
3411 INIT_LIST_HEAD(&tags->page_list);
3414 * rq_size is the size of the request plus driver payload, rounded
3415 * to the cacheline size
3417 rq_size = round_up(sizeof(struct request) + set->cmd_size,
3419 left = rq_size * depth;
3421 for (i = 0; i < depth; ) {
3422 int this_order = max_order;
3427 while (this_order && left < order_to_size(this_order - 1))
3431 page = alloc_pages_node(node,
3432 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
3438 if (order_to_size(this_order) < rq_size)
3445 page->private = this_order;
3446 list_add_tail(&page->lru, &tags->page_list);
3448 p = page_address(page);
3450 * Allow kmemleak to scan these pages as they contain pointers
3451 * to additional allocations like via ops->init_request().
3453 kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
3454 entries_per_page = order_to_size(this_order) / rq_size;
3455 to_do = min(entries_per_page, depth - i);
3456 left -= to_do * rq_size;
3457 for (j = 0; j < to_do; j++) {
3458 struct request *rq = p;
3460 tags->static_rqs[i] = rq;
3461 if (blk_mq_init_request(set, rq, hctx_idx, node)) {
3462 tags->static_rqs[i] = NULL;
3473 blk_mq_free_rqs(set, tags, hctx_idx);
3477 struct rq_iter_data {
3478 struct blk_mq_hw_ctx *hctx;
3482 static bool blk_mq_has_request(struct request *rq, void *data)
3484 struct rq_iter_data *iter_data = data;
3486 if (rq->mq_hctx != iter_data->hctx)
3488 iter_data->has_rq = true;
3492 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
3494 struct blk_mq_tags *tags = hctx->sched_tags ?
3495 hctx->sched_tags : hctx->tags;
3496 struct rq_iter_data data = {
3500 blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
3504 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
3505 struct blk_mq_hw_ctx *hctx)
3507 if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu)
3509 if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
3514 static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
3516 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3517 struct blk_mq_hw_ctx, cpuhp_online);
3519 if (!cpumask_test_cpu(cpu, hctx->cpumask) ||
3520 !blk_mq_last_cpu_in_hctx(cpu, hctx))
3524 * Prevent new request from being allocated on the current hctx.
3526 * The smp_mb__after_atomic() Pairs with the implied barrier in
3527 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
3528 * seen once we return from the tag allocator.
3530 set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3531 smp_mb__after_atomic();
3534 * Try to grab a reference to the queue and wait for any outstanding
3535 * requests. If we could not grab a reference the queue has been
3536 * frozen and there are no requests.
3538 if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
3539 while (blk_mq_hctx_has_requests(hctx))
3541 percpu_ref_put(&hctx->queue->q_usage_counter);
3547 static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
3549 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3550 struct blk_mq_hw_ctx, cpuhp_online);
3552 if (cpumask_test_cpu(cpu, hctx->cpumask))
3553 clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3558 * 'cpu' is going away. splice any existing rq_list entries from this
3559 * software queue to the hw queue dispatch list, and ensure that it
3562 static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
3564 struct blk_mq_hw_ctx *hctx;
3565 struct blk_mq_ctx *ctx;
3567 enum hctx_type type;
3569 hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
3570 if (!cpumask_test_cpu(cpu, hctx->cpumask))
3573 ctx = __blk_mq_get_ctx(hctx->queue, cpu);
3576 spin_lock(&ctx->lock);
3577 if (!list_empty(&ctx->rq_lists[type])) {
3578 list_splice_init(&ctx->rq_lists[type], &tmp);
3579 blk_mq_hctx_clear_pending(hctx, ctx);
3581 spin_unlock(&ctx->lock);
3583 if (list_empty(&tmp))
3586 spin_lock(&hctx->lock);
3587 list_splice_tail_init(&tmp, &hctx->dispatch);
3588 spin_unlock(&hctx->lock);
3590 blk_mq_run_hw_queue(hctx, true);
3594 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
3596 if (!(hctx->flags & BLK_MQ_F_STACKING))
3597 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3598 &hctx->cpuhp_online);
3599 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
3604 * Before freeing hw queue, clearing the flush request reference in
3605 * tags->rqs[] for avoiding potential UAF.
3607 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
3608 unsigned int queue_depth, struct request *flush_rq)
3611 unsigned long flags;
3613 /* The hw queue may not be mapped yet */
3617 WARN_ON_ONCE(req_ref_read(flush_rq) != 0);
3619 for (i = 0; i < queue_depth; i++)
3620 cmpxchg(&tags->rqs[i], flush_rq, NULL);
3623 * Wait until all pending iteration is done.
3625 * Request reference is cleared and it is guaranteed to be observed
3626 * after the ->lock is released.
3628 spin_lock_irqsave(&tags->lock, flags);
3629 spin_unlock_irqrestore(&tags->lock, flags);
3632 /* hctx->ctxs will be freed in queue's release handler */
3633 static void blk_mq_exit_hctx(struct request_queue *q,
3634 struct blk_mq_tag_set *set,
3635 struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
3637 struct request *flush_rq = hctx->fq->flush_rq;
3639 if (blk_mq_hw_queue_mapped(hctx))
3640 blk_mq_tag_idle(hctx);
3642 if (blk_queue_init_done(q))
3643 blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
3644 set->queue_depth, flush_rq);
3645 if (set->ops->exit_request)
3646 set->ops->exit_request(set, flush_rq, hctx_idx);
3648 if (set->ops->exit_hctx)
3649 set->ops->exit_hctx(hctx, hctx_idx);
3651 blk_mq_remove_cpuhp(hctx);
3653 xa_erase(&q->hctx_table, hctx_idx);
3655 spin_lock(&q->unused_hctx_lock);
3656 list_add(&hctx->hctx_list, &q->unused_hctx_list);
3657 spin_unlock(&q->unused_hctx_lock);
3660 static void blk_mq_exit_hw_queues(struct request_queue *q,
3661 struct blk_mq_tag_set *set, int nr_queue)
3663 struct blk_mq_hw_ctx *hctx;
3666 queue_for_each_hw_ctx(q, hctx, i) {
3669 blk_mq_exit_hctx(q, set, hctx, i);
3673 static int blk_mq_init_hctx(struct request_queue *q,
3674 struct blk_mq_tag_set *set,
3675 struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
3677 hctx->queue_num = hctx_idx;
3679 if (!(hctx->flags & BLK_MQ_F_STACKING))
3680 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3681 &hctx->cpuhp_online);
3682 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
3684 hctx->tags = set->tags[hctx_idx];
3686 if (set->ops->init_hctx &&
3687 set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
3688 goto unregister_cpu_notifier;
3690 if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
3694 if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL))
3700 if (set->ops->exit_request)
3701 set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
3703 if (set->ops->exit_hctx)
3704 set->ops->exit_hctx(hctx, hctx_idx);
3705 unregister_cpu_notifier:
3706 blk_mq_remove_cpuhp(hctx);
3710 static struct blk_mq_hw_ctx *
3711 blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
3714 struct blk_mq_hw_ctx *hctx;
3715 gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
3717 hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node);
3719 goto fail_alloc_hctx;
3721 if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
3724 atomic_set(&hctx->nr_active, 0);
3725 if (node == NUMA_NO_NODE)
3726 node = set->numa_node;
3727 hctx->numa_node = node;
3729 INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
3730 spin_lock_init(&hctx->lock);
3731 INIT_LIST_HEAD(&hctx->dispatch);
3733 hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
3735 INIT_LIST_HEAD(&hctx->hctx_list);
3738 * Allocate space for all possible cpus to avoid allocation at
3741 hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
3746 if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
3747 gfp, node, false, false))
3751 spin_lock_init(&hctx->dispatch_wait_lock);
3752 init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
3753 INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
3755 hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
3759 blk_mq_hctx_kobj_init(hctx);
3764 sbitmap_free(&hctx->ctx_map);
3768 free_cpumask_var(hctx->cpumask);
3775 static void blk_mq_init_cpu_queues(struct request_queue *q,
3776 unsigned int nr_hw_queues)
3778 struct blk_mq_tag_set *set = q->tag_set;
3781 for_each_possible_cpu(i) {
3782 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
3783 struct blk_mq_hw_ctx *hctx;
3787 spin_lock_init(&__ctx->lock);
3788 for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
3789 INIT_LIST_HEAD(&__ctx->rq_lists[k]);
3794 * Set local node, IFF we have more than one hw queue. If
3795 * not, we remain on the home node of the device
3797 for (j = 0; j < set->nr_maps; j++) {
3798 hctx = blk_mq_map_queue_type(q, j, i);
3799 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
3800 hctx->numa_node = cpu_to_node(i);
3805 struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3806 unsigned int hctx_idx,
3809 struct blk_mq_tags *tags;
3812 tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags);
3816 ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
3818 blk_mq_free_rq_map(tags);
3825 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3828 if (blk_mq_is_shared_tags(set->flags)) {
3829 set->tags[hctx_idx] = set->shared_tags;
3834 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
3837 return set->tags[hctx_idx];
3840 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3841 struct blk_mq_tags *tags,
3842 unsigned int hctx_idx)
3845 blk_mq_free_rqs(set, tags, hctx_idx);
3846 blk_mq_free_rq_map(tags);
3850 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3851 unsigned int hctx_idx)
3853 if (!blk_mq_is_shared_tags(set->flags))
3854 blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx);
3856 set->tags[hctx_idx] = NULL;
3859 static void blk_mq_map_swqueue(struct request_queue *q)
3861 unsigned int j, hctx_idx;
3863 struct blk_mq_hw_ctx *hctx;
3864 struct blk_mq_ctx *ctx;
3865 struct blk_mq_tag_set *set = q->tag_set;
3867 queue_for_each_hw_ctx(q, hctx, i) {
3868 cpumask_clear(hctx->cpumask);
3870 hctx->dispatch_from = NULL;
3874 * Map software to hardware queues.
3876 * If the cpu isn't present, the cpu is mapped to first hctx.
3878 for_each_possible_cpu(i) {
3880 ctx = per_cpu_ptr(q->queue_ctx, i);
3881 for (j = 0; j < set->nr_maps; j++) {
3882 if (!set->map[j].nr_queues) {
3883 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3884 HCTX_TYPE_DEFAULT, i);
3887 hctx_idx = set->map[j].mq_map[i];
3888 /* unmapped hw queue can be remapped after CPU topo changed */
3889 if (!set->tags[hctx_idx] &&
3890 !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
3892 * If tags initialization fail for some hctx,
3893 * that hctx won't be brought online. In this
3894 * case, remap the current ctx to hctx[0] which
3895 * is guaranteed to always have tags allocated
3897 set->map[j].mq_map[i] = 0;
3900 hctx = blk_mq_map_queue_type(q, j, i);
3901 ctx->hctxs[j] = hctx;
3903 * If the CPU is already set in the mask, then we've
3904 * mapped this one already. This can happen if
3905 * devices share queues across queue maps.
3907 if (cpumask_test_cpu(i, hctx->cpumask))
3910 cpumask_set_cpu(i, hctx->cpumask);
3912 ctx->index_hw[hctx->type] = hctx->nr_ctx;
3913 hctx->ctxs[hctx->nr_ctx++] = ctx;
3916 * If the nr_ctx type overflows, we have exceeded the
3917 * amount of sw queues we can support.
3919 BUG_ON(!hctx->nr_ctx);
3922 for (; j < HCTX_MAX_TYPES; j++)
3923 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3924 HCTX_TYPE_DEFAULT, i);
3927 queue_for_each_hw_ctx(q, hctx, i) {
3929 * If no software queues are mapped to this hardware queue,
3930 * disable it and free the request entries.
3932 if (!hctx->nr_ctx) {
3933 /* Never unmap queue 0. We need it as a
3934 * fallback in case of a new remap fails
3938 __blk_mq_free_map_and_rqs(set, i);
3944 hctx->tags = set->tags[i];
3945 WARN_ON(!hctx->tags);
3948 * Set the map size to the number of mapped software queues.
3949 * This is more accurate and more efficient than looping
3950 * over all possibly mapped software queues.
3952 sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
3955 * Initialize batch roundrobin counts
3957 hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
3958 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
3963 * Caller needs to ensure that we're either frozen/quiesced, or that
3964 * the queue isn't live yet.
3966 static void queue_set_hctx_shared(struct request_queue *q, bool shared)
3968 struct blk_mq_hw_ctx *hctx;
3971 queue_for_each_hw_ctx(q, hctx, i) {
3973 hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3975 blk_mq_tag_idle(hctx);
3976 hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3981 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
3984 struct request_queue *q;
3986 lockdep_assert_held(&set->tag_list_lock);
3988 list_for_each_entry(q, &set->tag_list, tag_set_list) {
3989 blk_mq_freeze_queue(q);
3990 queue_set_hctx_shared(q, shared);
3991 blk_mq_unfreeze_queue(q);
3995 static void blk_mq_del_queue_tag_set(struct request_queue *q)
3997 struct blk_mq_tag_set *set = q->tag_set;
3999 mutex_lock(&set->tag_list_lock);
4000 list_del(&q->tag_set_list);
4001 if (list_is_singular(&set->tag_list)) {
4002 /* just transitioned to unshared */
4003 set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
4004 /* update existing queue */
4005 blk_mq_update_tag_set_shared(set, false);
4007 mutex_unlock(&set->tag_list_lock);
4008 INIT_LIST_HEAD(&q->tag_set_list);
4011 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
4012 struct request_queue *q)
4014 mutex_lock(&set->tag_list_lock);
4017 * Check to see if we're transitioning to shared (from 1 to 2 queues).
4019 if (!list_empty(&set->tag_list) &&
4020 !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
4021 set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
4022 /* update existing queue */
4023 blk_mq_update_tag_set_shared(set, true);
4025 if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
4026 queue_set_hctx_shared(q, true);
4027 list_add_tail(&q->tag_set_list, &set->tag_list);
4029 mutex_unlock(&set->tag_list_lock);
4032 /* All allocations will be freed in release handler of q->mq_kobj */
4033 static int blk_mq_alloc_ctxs(struct request_queue *q)
4035 struct blk_mq_ctxs *ctxs;
4038 ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
4042 ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
4043 if (!ctxs->queue_ctx)
4046 for_each_possible_cpu(cpu) {
4047 struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
4051 q->mq_kobj = &ctxs->kobj;
4052 q->queue_ctx = ctxs->queue_ctx;
4061 * It is the actual release handler for mq, but we do it from
4062 * request queue's release handler for avoiding use-after-free
4063 * and headache because q->mq_kobj shouldn't have been introduced,
4064 * but we can't group ctx/kctx kobj without it.
4066 void blk_mq_release(struct request_queue *q)
4068 struct blk_mq_hw_ctx *hctx, *next;
4071 queue_for_each_hw_ctx(q, hctx, i)
4072 WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
4074 /* all hctx are in .unused_hctx_list now */
4075 list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
4076 list_del_init(&hctx->hctx_list);
4077 kobject_put(&hctx->kobj);
4080 xa_destroy(&q->hctx_table);
4083 * release .mq_kobj and sw queue's kobject now because
4084 * both share lifetime with request queue.
4086 blk_mq_sysfs_deinit(q);
4089 static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
4092 struct request_queue *q;
4095 q = blk_alloc_queue(set->numa_node);
4097 return ERR_PTR(-ENOMEM);
4098 q->queuedata = queuedata;
4099 ret = blk_mq_init_allocated_queue(set, q);
4102 return ERR_PTR(ret);
4107 struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
4109 return blk_mq_init_queue_data(set, NULL);
4111 EXPORT_SYMBOL(blk_mq_init_queue);
4114 * blk_mq_destroy_queue - shutdown a request queue
4115 * @q: request queue to shutdown
4117 * This shuts down a request queue allocated by blk_mq_init_queue(). All future
4118 * requests will be failed with -ENODEV. The caller is responsible for dropping
4119 * the reference from blk_mq_init_queue() by calling blk_put_queue().
4121 * Context: can sleep
4123 void blk_mq_destroy_queue(struct request_queue *q)
4125 WARN_ON_ONCE(!queue_is_mq(q));
4126 WARN_ON_ONCE(blk_queue_registered(q));
4130 blk_queue_flag_set(QUEUE_FLAG_DYING, q);
4131 blk_queue_start_drain(q);
4132 blk_mq_freeze_queue_wait(q);
4135 blk_mq_cancel_work_sync(q);
4136 blk_mq_exit_queue(q);
4138 EXPORT_SYMBOL(blk_mq_destroy_queue);
4140 struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
4141 struct lock_class_key *lkclass)
4143 struct request_queue *q;
4144 struct gendisk *disk;
4146 q = blk_mq_init_queue_data(set, queuedata);
4150 disk = __alloc_disk_node(q, set->numa_node, lkclass);
4152 blk_mq_destroy_queue(q);
4154 return ERR_PTR(-ENOMEM);
4156 set_bit(GD_OWNS_QUEUE, &disk->state);
4159 EXPORT_SYMBOL(__blk_mq_alloc_disk);
4161 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
4162 struct lock_class_key *lkclass)
4164 struct gendisk *disk;
4166 if (!blk_get_queue(q))
4168 disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass);
4173 EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue);
4175 static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
4176 struct blk_mq_tag_set *set, struct request_queue *q,
4177 int hctx_idx, int node)
4179 struct blk_mq_hw_ctx *hctx = NULL, *tmp;
4181 /* reuse dead hctx first */
4182 spin_lock(&q->unused_hctx_lock);
4183 list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
4184 if (tmp->numa_node == node) {
4190 list_del_init(&hctx->hctx_list);
4191 spin_unlock(&q->unused_hctx_lock);
4194 hctx = blk_mq_alloc_hctx(q, set, node);
4198 if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
4204 kobject_put(&hctx->kobj);
4209 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
4210 struct request_queue *q)
4212 struct blk_mq_hw_ctx *hctx;
4215 /* protect against switching io scheduler */
4216 mutex_lock(&q->sysfs_lock);
4217 for (i = 0; i < set->nr_hw_queues; i++) {
4219 int node = blk_mq_get_hctx_node(set, i);
4220 struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i);
4223 old_node = old_hctx->numa_node;
4224 blk_mq_exit_hctx(q, set, old_hctx, i);
4227 if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) {
4230 pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
4232 hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node);
4233 WARN_ON_ONCE(!hctx);
4237 * Increasing nr_hw_queues fails. Free the newly allocated
4238 * hctxs and keep the previous q->nr_hw_queues.
4240 if (i != set->nr_hw_queues) {
4241 j = q->nr_hw_queues;
4244 q->nr_hw_queues = set->nr_hw_queues;
4247 xa_for_each_start(&q->hctx_table, j, hctx, j)
4248 blk_mq_exit_hctx(q, set, hctx, j);
4249 mutex_unlock(&q->sysfs_lock);
4252 static void blk_mq_update_poll_flag(struct request_queue *q)
4254 struct blk_mq_tag_set *set = q->tag_set;
4256 if (set->nr_maps > HCTX_TYPE_POLL &&
4257 set->map[HCTX_TYPE_POLL].nr_queues)
4258 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
4260 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
4263 int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
4264 struct request_queue *q)
4266 /* mark the queue as mq asap */
4267 q->mq_ops = set->ops;
4269 if (blk_mq_alloc_ctxs(q))
4272 /* init q->mq_kobj and sw queues' kobjects */
4273 blk_mq_sysfs_init(q);
4275 INIT_LIST_HEAD(&q->unused_hctx_list);
4276 spin_lock_init(&q->unused_hctx_lock);
4278 xa_init(&q->hctx_table);
4280 blk_mq_realloc_hw_ctxs(set, q);
4281 if (!q->nr_hw_queues)
4284 INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
4285 blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
4289 q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
4290 blk_mq_update_poll_flag(q);
4292 INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
4293 INIT_LIST_HEAD(&q->flush_list);
4294 INIT_LIST_HEAD(&q->requeue_list);
4295 spin_lock_init(&q->requeue_lock);
4297 q->nr_requests = set->queue_depth;
4299 blk_mq_init_cpu_queues(q, set->nr_hw_queues);
4300 blk_mq_add_queue_tag_set(set, q);
4301 blk_mq_map_swqueue(q);
4310 EXPORT_SYMBOL(blk_mq_init_allocated_queue);
4312 /* tags can _not_ be used after returning from blk_mq_exit_queue */
4313 void blk_mq_exit_queue(struct request_queue *q)
4315 struct blk_mq_tag_set *set = q->tag_set;
4317 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
4318 blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
4319 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
4320 blk_mq_del_queue_tag_set(q);
4323 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
4327 if (blk_mq_is_shared_tags(set->flags)) {
4328 set->shared_tags = blk_mq_alloc_map_and_rqs(set,
4331 if (!set->shared_tags)
4335 for (i = 0; i < set->nr_hw_queues; i++) {
4336 if (!__blk_mq_alloc_map_and_rqs(set, i))
4345 __blk_mq_free_map_and_rqs(set, i);
4347 if (blk_mq_is_shared_tags(set->flags)) {
4348 blk_mq_free_map_and_rqs(set, set->shared_tags,
4349 BLK_MQ_NO_HCTX_IDX);
4356 * Allocate the request maps associated with this tag_set. Note that this
4357 * may reduce the depth asked for, if memory is tight. set->queue_depth
4358 * will be updated to reflect the allocated depth.
4360 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
4365 depth = set->queue_depth;
4367 err = __blk_mq_alloc_rq_maps(set);
4371 set->queue_depth >>= 1;
4372 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
4376 } while (set->queue_depth);
4378 if (!set->queue_depth || err) {
4379 pr_err("blk-mq: failed to allocate request map\n");
4383 if (depth != set->queue_depth)
4384 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
4385 depth, set->queue_depth);
4390 static void blk_mq_update_queue_map(struct blk_mq_tag_set *set)
4393 * blk_mq_map_queues() and multiple .map_queues() implementations
4394 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
4395 * number of hardware queues.
4397 if (set->nr_maps == 1)
4398 set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
4400 if (set->ops->map_queues && !is_kdump_kernel()) {
4404 * transport .map_queues is usually done in the following
4407 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
4408 * mask = get_cpu_mask(queue)
4409 * for_each_cpu(cpu, mask)
4410 * set->map[x].mq_map[cpu] = queue;
4413 * When we need to remap, the table has to be cleared for
4414 * killing stale mapping since one CPU may not be mapped
4417 for (i = 0; i < set->nr_maps; i++)
4418 blk_mq_clear_mq_map(&set->map[i]);
4420 set->ops->map_queues(set);
4422 BUG_ON(set->nr_maps > 1);
4423 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
4427 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
4428 int new_nr_hw_queues)
4430 struct blk_mq_tags **new_tags;
4433 if (set->nr_hw_queues >= new_nr_hw_queues)
4436 new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
4437 GFP_KERNEL, set->numa_node);
4442 memcpy(new_tags, set->tags, set->nr_hw_queues *
4443 sizeof(*set->tags));
4445 set->tags = new_tags;
4447 for (i = set->nr_hw_queues; i < new_nr_hw_queues; i++) {
4448 if (!__blk_mq_alloc_map_and_rqs(set, i)) {
4449 while (--i >= set->nr_hw_queues)
4450 __blk_mq_free_map_and_rqs(set, i);
4457 set->nr_hw_queues = new_nr_hw_queues;
4462 * Alloc a tag set to be associated with one or more request queues.
4463 * May fail with EINVAL for various error conditions. May adjust the
4464 * requested depth down, if it's too large. In that case, the set
4465 * value will be stored in set->queue_depth.
4467 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
4471 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
4473 if (!set->nr_hw_queues)
4475 if (!set->queue_depth)
4477 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
4480 if (!set->ops->queue_rq)
4483 if (!set->ops->get_budget ^ !set->ops->put_budget)
4486 if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
4487 pr_info("blk-mq: reduced tag depth to %u\n",
4489 set->queue_depth = BLK_MQ_MAX_DEPTH;
4494 else if (set->nr_maps > HCTX_MAX_TYPES)
4498 * If a crashdump is active, then we are potentially in a very
4499 * memory constrained environment. Limit us to 1 queue and
4500 * 64 tags to prevent using too much memory.
4502 if (is_kdump_kernel()) {
4503 set->nr_hw_queues = 1;
4505 set->queue_depth = min(64U, set->queue_depth);
4508 * There is no use for more h/w queues than cpus if we just have
4511 if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
4512 set->nr_hw_queues = nr_cpu_ids;
4514 if (set->flags & BLK_MQ_F_BLOCKING) {
4515 set->srcu = kmalloc(sizeof(*set->srcu), GFP_KERNEL);
4518 ret = init_srcu_struct(set->srcu);
4524 set->tags = kcalloc_node(set->nr_hw_queues,
4525 sizeof(struct blk_mq_tags *), GFP_KERNEL,
4528 goto out_cleanup_srcu;
4530 for (i = 0; i < set->nr_maps; i++) {
4531 set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
4532 sizeof(set->map[i].mq_map[0]),
4533 GFP_KERNEL, set->numa_node);
4534 if (!set->map[i].mq_map)
4535 goto out_free_mq_map;
4536 set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues;
4539 blk_mq_update_queue_map(set);
4541 ret = blk_mq_alloc_set_map_and_rqs(set);
4543 goto out_free_mq_map;
4545 mutex_init(&set->tag_list_lock);
4546 INIT_LIST_HEAD(&set->tag_list);
4551 for (i = 0; i < set->nr_maps; i++) {
4552 kfree(set->map[i].mq_map);
4553 set->map[i].mq_map = NULL;
4558 if (set->flags & BLK_MQ_F_BLOCKING)
4559 cleanup_srcu_struct(set->srcu);
4561 if (set->flags & BLK_MQ_F_BLOCKING)
4565 EXPORT_SYMBOL(blk_mq_alloc_tag_set);
4567 /* allocate and initialize a tagset for a simple single-queue device */
4568 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set,
4569 const struct blk_mq_ops *ops, unsigned int queue_depth,
4570 unsigned int set_flags)
4572 memset(set, 0, sizeof(*set));
4574 set->nr_hw_queues = 1;
4576 set->queue_depth = queue_depth;
4577 set->numa_node = NUMA_NO_NODE;
4578 set->flags = set_flags;
4579 return blk_mq_alloc_tag_set(set);
4581 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set);
4583 void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
4587 for (i = 0; i < set->nr_hw_queues; i++)
4588 __blk_mq_free_map_and_rqs(set, i);
4590 if (blk_mq_is_shared_tags(set->flags)) {
4591 blk_mq_free_map_and_rqs(set, set->shared_tags,
4592 BLK_MQ_NO_HCTX_IDX);
4595 for (j = 0; j < set->nr_maps; j++) {
4596 kfree(set->map[j].mq_map);
4597 set->map[j].mq_map = NULL;
4602 if (set->flags & BLK_MQ_F_BLOCKING) {
4603 cleanup_srcu_struct(set->srcu);
4607 EXPORT_SYMBOL(blk_mq_free_tag_set);
4609 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
4611 struct blk_mq_tag_set *set = q->tag_set;
4612 struct blk_mq_hw_ctx *hctx;
4619 if (q->nr_requests == nr)
4622 blk_mq_freeze_queue(q);
4623 blk_mq_quiesce_queue(q);
4626 queue_for_each_hw_ctx(q, hctx, i) {
4630 * If we're using an MQ scheduler, just update the scheduler
4631 * queue depth. This is similar to what the old code would do.
4633 if (hctx->sched_tags) {
4634 ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
4637 ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
4642 if (q->elevator && q->elevator->type->ops.depth_updated)
4643 q->elevator->type->ops.depth_updated(hctx);
4646 q->nr_requests = nr;
4647 if (blk_mq_is_shared_tags(set->flags)) {
4649 blk_mq_tag_update_sched_shared_tags(q);
4651 blk_mq_tag_resize_shared_tags(set, nr);
4655 blk_mq_unquiesce_queue(q);
4656 blk_mq_unfreeze_queue(q);
4662 * request_queue and elevator_type pair.
4663 * It is just used by __blk_mq_update_nr_hw_queues to cache
4664 * the elevator_type associated with a request_queue.
4666 struct blk_mq_qe_pair {
4667 struct list_head node;
4668 struct request_queue *q;
4669 struct elevator_type *type;
4673 * Cache the elevator_type in qe pair list and switch the
4674 * io scheduler to 'none'
4676 static bool blk_mq_elv_switch_none(struct list_head *head,
4677 struct request_queue *q)
4679 struct blk_mq_qe_pair *qe;
4681 qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
4685 /* q->elevator needs protection from ->sysfs_lock */
4686 mutex_lock(&q->sysfs_lock);
4688 /* the check has to be done with holding sysfs_lock */
4694 INIT_LIST_HEAD(&qe->node);
4696 qe->type = q->elevator->type;
4697 /* keep a reference to the elevator module as we'll switch back */
4698 __elevator_get(qe->type);
4699 list_add(&qe->node, head);
4700 elevator_disable(q);
4702 mutex_unlock(&q->sysfs_lock);
4707 static struct blk_mq_qe_pair *blk_lookup_qe_pair(struct list_head *head,
4708 struct request_queue *q)
4710 struct blk_mq_qe_pair *qe;
4712 list_for_each_entry(qe, head, node)
4719 static void blk_mq_elv_switch_back(struct list_head *head,
4720 struct request_queue *q)
4722 struct blk_mq_qe_pair *qe;
4723 struct elevator_type *t;
4725 qe = blk_lookup_qe_pair(head, q);
4729 list_del(&qe->node);
4732 mutex_lock(&q->sysfs_lock);
4733 elevator_switch(q, t);
4734 /* drop the reference acquired in blk_mq_elv_switch_none */
4736 mutex_unlock(&q->sysfs_lock);
4739 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
4742 struct request_queue *q;
4744 int prev_nr_hw_queues = set->nr_hw_queues;
4747 lockdep_assert_held(&set->tag_list_lock);
4749 if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
4750 nr_hw_queues = nr_cpu_ids;
4751 if (nr_hw_queues < 1)
4753 if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
4756 list_for_each_entry(q, &set->tag_list, tag_set_list)
4757 blk_mq_freeze_queue(q);
4759 * Switch IO scheduler to 'none', cleaning up the data associated
4760 * with the previous scheduler. We will switch back once we are done
4761 * updating the new sw to hw queue mappings.
4763 list_for_each_entry(q, &set->tag_list, tag_set_list)
4764 if (!blk_mq_elv_switch_none(&head, q))
4767 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4768 blk_mq_debugfs_unregister_hctxs(q);
4769 blk_mq_sysfs_unregister_hctxs(q);
4772 if (blk_mq_realloc_tag_set_tags(set, nr_hw_queues) < 0)
4776 blk_mq_update_queue_map(set);
4777 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4778 blk_mq_realloc_hw_ctxs(set, q);
4779 blk_mq_update_poll_flag(q);
4780 if (q->nr_hw_queues != set->nr_hw_queues) {
4781 int i = prev_nr_hw_queues;
4783 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4784 nr_hw_queues, prev_nr_hw_queues);
4785 for (; i < set->nr_hw_queues; i++)
4786 __blk_mq_free_map_and_rqs(set, i);
4788 set->nr_hw_queues = prev_nr_hw_queues;
4791 blk_mq_map_swqueue(q);
4795 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4796 blk_mq_sysfs_register_hctxs(q);
4797 blk_mq_debugfs_register_hctxs(q);
4801 list_for_each_entry(q, &set->tag_list, tag_set_list)
4802 blk_mq_elv_switch_back(&head, q);
4804 list_for_each_entry(q, &set->tag_list, tag_set_list)
4805 blk_mq_unfreeze_queue(q);
4807 /* Free the excess tags when nr_hw_queues shrink. */
4808 for (i = set->nr_hw_queues; i < prev_nr_hw_queues; i++)
4809 __blk_mq_free_map_and_rqs(set, i);
4812 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
4814 mutex_lock(&set->tag_list_lock);
4815 __blk_mq_update_nr_hw_queues(set, nr_hw_queues);
4816 mutex_unlock(&set->tag_list_lock);
4818 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
4820 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
4821 struct io_comp_batch *iob, unsigned int flags)
4823 long state = get_current_state();
4827 ret = q->mq_ops->poll(hctx, iob);
4829 __set_current_state(TASK_RUNNING);
4833 if (signal_pending_state(state, current))
4834 __set_current_state(TASK_RUNNING);
4835 if (task_is_running(current))
4838 if (ret < 0 || (flags & BLK_POLL_ONESHOT))
4841 } while (!need_resched());
4843 __set_current_state(TASK_RUNNING);
4847 int blk_mq_poll(struct request_queue *q, blk_qc_t cookie,
4848 struct io_comp_batch *iob, unsigned int flags)
4850 struct blk_mq_hw_ctx *hctx = xa_load(&q->hctx_table, cookie);
4852 return blk_hctx_poll(q, hctx, iob, flags);
4855 int blk_rq_poll(struct request *rq, struct io_comp_batch *iob,
4856 unsigned int poll_flags)
4858 struct request_queue *q = rq->q;
4861 if (!blk_rq_is_poll(rq))
4863 if (!percpu_ref_tryget(&q->q_usage_counter))
4866 ret = blk_hctx_poll(q, rq->mq_hctx, iob, poll_flags);
4871 EXPORT_SYMBOL_GPL(blk_rq_poll);
4873 unsigned int blk_mq_rq_cpu(struct request *rq)
4875 return rq->mq_ctx->cpu;
4877 EXPORT_SYMBOL(blk_mq_rq_cpu);
4879 void blk_mq_cancel_work_sync(struct request_queue *q)
4881 struct blk_mq_hw_ctx *hctx;
4884 cancel_delayed_work_sync(&q->requeue_work);
4886 queue_for_each_hw_ctx(q, hctx, i)
4887 cancel_delayed_work_sync(&hctx->run_work);
4890 static int __init blk_mq_init(void)
4894 for_each_possible_cpu(i)
4895 init_llist_head(&per_cpu(blk_cpu_done, i));
4896 for_each_possible_cpu(i)
4897 INIT_CSD(&per_cpu(blk_cpu_csd, i),
4898 __blk_mq_complete_request_remote, NULL);
4899 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
4901 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
4902 "block/softirq:dead", NULL,
4903 blk_softirq_cpu_dead);
4904 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
4905 blk_mq_hctx_notify_dead);
4906 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
4907 blk_mq_hctx_notify_online,
4908 blk_mq_hctx_notify_offline);
4911 subsys_initcall(blk_mq_init);