1 // SPDX-License-Identifier: GPL-2.0
3 * Block multiqueue core code
5 * Copyright (C) 2013-2014 Jens Axboe
6 * Copyright (C) 2013-2014 Christoph Hellwig
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/backing-dev.h>
11 #include <linux/bio.h>
12 #include <linux/blkdev.h>
13 #include <linux/blk-integrity.h>
14 #include <linux/kmemleak.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/workqueue.h>
19 #include <linux/smp.h>
20 #include <linux/interrupt.h>
21 #include <linux/llist.h>
22 #include <linux/cpu.h>
23 #include <linux/cache.h>
24 #include <linux/sched/sysctl.h>
25 #include <linux/sched/topology.h>
26 #include <linux/sched/signal.h>
27 #include <linux/delay.h>
28 #include <linux/crash_dump.h>
29 #include <linux/prefetch.h>
30 #include <linux/blk-crypto.h>
31 #include <linux/part_stat.h>
33 #include <trace/events/block.h>
35 #include <linux/t10-pi.h>
38 #include "blk-mq-debugfs.h"
41 #include "blk-mq-sched.h"
42 #include "blk-rq-qos.h"
43 #include "blk-ioprio.h"
45 static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
46 static DEFINE_PER_CPU(call_single_data_t, blk_cpu_csd);
48 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags);
49 static void blk_mq_request_bypass_insert(struct request *rq,
51 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
52 struct list_head *list);
53 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
54 struct io_comp_batch *iob, unsigned int flags);
57 * Check if any of the ctx, dispatch list or elevator
58 * have pending work in this hardware queue.
60 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
62 return !list_empty_careful(&hctx->dispatch) ||
63 sbitmap_any_bit_set(&hctx->ctx_map) ||
64 blk_mq_sched_has_work(hctx);
68 * Mark this ctx as having pending work in this hardware queue
70 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
71 struct blk_mq_ctx *ctx)
73 const int bit = ctx->index_hw[hctx->type];
75 if (!sbitmap_test_bit(&hctx->ctx_map, bit))
76 sbitmap_set_bit(&hctx->ctx_map, bit);
79 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
80 struct blk_mq_ctx *ctx)
82 const int bit = ctx->index_hw[hctx->type];
84 sbitmap_clear_bit(&hctx->ctx_map, bit);
88 struct block_device *part;
89 unsigned int inflight[2];
92 static bool blk_mq_check_inflight(struct request *rq, void *priv)
94 struct mq_inflight *mi = priv;
96 if (rq->part && blk_do_io_stat(rq) &&
97 (!mi->part->bd_partno || rq->part == mi->part) &&
98 blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
99 mi->inflight[rq_data_dir(rq)]++;
104 unsigned int blk_mq_in_flight(struct request_queue *q,
105 struct block_device *part)
107 struct mq_inflight mi = { .part = part };
109 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
111 return mi.inflight[0] + mi.inflight[1];
114 void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
115 unsigned int inflight[2])
117 struct mq_inflight mi = { .part = part };
119 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
120 inflight[0] = mi.inflight[0];
121 inflight[1] = mi.inflight[1];
124 void blk_freeze_queue_start(struct request_queue *q)
126 mutex_lock(&q->mq_freeze_lock);
127 if (++q->mq_freeze_depth == 1) {
128 percpu_ref_kill(&q->q_usage_counter);
129 mutex_unlock(&q->mq_freeze_lock);
131 blk_mq_run_hw_queues(q, false);
133 mutex_unlock(&q->mq_freeze_lock);
136 EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
138 void blk_mq_freeze_queue_wait(struct request_queue *q)
140 wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
142 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
144 int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
145 unsigned long timeout)
147 return wait_event_timeout(q->mq_freeze_wq,
148 percpu_ref_is_zero(&q->q_usage_counter),
151 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
154 * Guarantee no request is in use, so we can change any data structure of
155 * the queue afterward.
157 void blk_freeze_queue(struct request_queue *q)
160 * In the !blk_mq case we are only calling this to kill the
161 * q_usage_counter, otherwise this increases the freeze depth
162 * and waits for it to return to zero. For this reason there is
163 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
164 * exported to drivers as the only user for unfreeze is blk_mq.
166 blk_freeze_queue_start(q);
167 blk_mq_freeze_queue_wait(q);
170 void blk_mq_freeze_queue(struct request_queue *q)
173 * ...just an alias to keep freeze and unfreeze actions balanced
174 * in the blk_mq_* namespace
178 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
180 void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
182 mutex_lock(&q->mq_freeze_lock);
184 q->q_usage_counter.data->force_atomic = true;
185 q->mq_freeze_depth--;
186 WARN_ON_ONCE(q->mq_freeze_depth < 0);
187 if (!q->mq_freeze_depth) {
188 percpu_ref_resurrect(&q->q_usage_counter);
189 wake_up_all(&q->mq_freeze_wq);
191 mutex_unlock(&q->mq_freeze_lock);
194 void blk_mq_unfreeze_queue(struct request_queue *q)
196 __blk_mq_unfreeze_queue(q, false);
198 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
201 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
202 * mpt3sas driver such that this function can be removed.
204 void blk_mq_quiesce_queue_nowait(struct request_queue *q)
208 spin_lock_irqsave(&q->queue_lock, flags);
209 if (!q->quiesce_depth++)
210 blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
211 spin_unlock_irqrestore(&q->queue_lock, flags);
213 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
216 * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
217 * @set: tag_set to wait on
219 * Note: it is driver's responsibility for making sure that quiesce has
220 * been started on or more of the request_queues of the tag_set. This
221 * function only waits for the quiesce on those request_queues that had
222 * the quiesce flag set using blk_mq_quiesce_queue_nowait.
224 void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set)
226 if (set->flags & BLK_MQ_F_BLOCKING)
227 synchronize_srcu(set->srcu);
231 EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
234 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
237 * Note: this function does not prevent that the struct request end_io()
238 * callback function is invoked. Once this function is returned, we make
239 * sure no dispatch can happen until the queue is unquiesced via
240 * blk_mq_unquiesce_queue().
242 void blk_mq_quiesce_queue(struct request_queue *q)
244 blk_mq_quiesce_queue_nowait(q);
245 /* nothing to wait for non-mq queues */
247 blk_mq_wait_quiesce_done(q->tag_set);
249 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
252 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
255 * This function recovers queue into the state before quiescing
256 * which is done by blk_mq_quiesce_queue.
258 void blk_mq_unquiesce_queue(struct request_queue *q)
261 bool run_queue = false;
263 spin_lock_irqsave(&q->queue_lock, flags);
264 if (WARN_ON_ONCE(q->quiesce_depth <= 0)) {
266 } else if (!--q->quiesce_depth) {
267 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
270 spin_unlock_irqrestore(&q->queue_lock, flags);
272 /* dispatch requests which are inserted during quiescing */
274 blk_mq_run_hw_queues(q, true);
276 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
278 void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set)
280 struct request_queue *q;
282 mutex_lock(&set->tag_list_lock);
283 list_for_each_entry(q, &set->tag_list, tag_set_list) {
284 if (!blk_queue_skip_tagset_quiesce(q))
285 blk_mq_quiesce_queue_nowait(q);
287 blk_mq_wait_quiesce_done(set);
288 mutex_unlock(&set->tag_list_lock);
290 EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);
292 void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set)
294 struct request_queue *q;
296 mutex_lock(&set->tag_list_lock);
297 list_for_each_entry(q, &set->tag_list, tag_set_list) {
298 if (!blk_queue_skip_tagset_quiesce(q))
299 blk_mq_unquiesce_queue(q);
301 mutex_unlock(&set->tag_list_lock);
303 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset);
305 void blk_mq_wake_waiters(struct request_queue *q)
307 struct blk_mq_hw_ctx *hctx;
310 queue_for_each_hw_ctx(q, hctx, i)
311 if (blk_mq_hw_queue_mapped(hctx))
312 blk_mq_tag_wakeup_all(hctx->tags, true);
315 void blk_rq_init(struct request_queue *q, struct request *rq)
317 memset(rq, 0, sizeof(*rq));
319 INIT_LIST_HEAD(&rq->queuelist);
321 rq->__sector = (sector_t) -1;
322 INIT_HLIST_NODE(&rq->hash);
323 RB_CLEAR_NODE(&rq->rb_node);
324 rq->tag = BLK_MQ_NO_TAG;
325 rq->internal_tag = BLK_MQ_NO_TAG;
326 rq->start_time_ns = ktime_get_ns();
328 blk_crypto_rq_set_defaults(rq);
330 EXPORT_SYMBOL(blk_rq_init);
332 /* Set start and alloc time when the allocated request is actually used */
333 static inline void blk_mq_rq_time_init(struct request *rq, u64 alloc_time_ns)
335 if (blk_mq_need_time_stamp(rq))
336 rq->start_time_ns = ktime_get_ns();
338 rq->start_time_ns = 0;
340 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
341 if (blk_queue_rq_alloc_time(rq->q))
342 rq->alloc_time_ns = alloc_time_ns ?: rq->start_time_ns;
344 rq->alloc_time_ns = 0;
348 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
349 struct blk_mq_tags *tags, unsigned int tag)
351 struct blk_mq_ctx *ctx = data->ctx;
352 struct blk_mq_hw_ctx *hctx = data->hctx;
353 struct request_queue *q = data->q;
354 struct request *rq = tags->static_rqs[tag];
359 rq->cmd_flags = data->cmd_flags;
361 if (data->flags & BLK_MQ_REQ_PM)
362 data->rq_flags |= RQF_PM;
363 if (blk_queue_io_stat(q))
364 data->rq_flags |= RQF_IO_STAT;
365 rq->rq_flags = data->rq_flags;
367 if (data->rq_flags & RQF_SCHED_TAGS) {
368 rq->tag = BLK_MQ_NO_TAG;
369 rq->internal_tag = tag;
372 rq->internal_tag = BLK_MQ_NO_TAG;
377 rq->io_start_time_ns = 0;
378 rq->stats_sectors = 0;
379 rq->nr_phys_segments = 0;
380 #if defined(CONFIG_BLK_DEV_INTEGRITY)
381 rq->nr_integrity_segments = 0;
384 rq->end_io_data = NULL;
386 blk_crypto_rq_set_defaults(rq);
387 INIT_LIST_HEAD(&rq->queuelist);
388 /* tag was already set */
389 WRITE_ONCE(rq->deadline, 0);
392 if (rq->rq_flags & RQF_USE_SCHED) {
393 struct elevator_queue *e = data->q->elevator;
395 INIT_HLIST_NODE(&rq->hash);
396 RB_CLEAR_NODE(&rq->rb_node);
398 if (e->type->ops.prepare_request)
399 e->type->ops.prepare_request(rq);
405 static inline struct request *
406 __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data)
408 unsigned int tag, tag_offset;
409 struct blk_mq_tags *tags;
411 unsigned long tag_mask;
414 tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset);
415 if (unlikely(!tag_mask))
418 tags = blk_mq_tags_from_data(data);
419 for (i = 0; tag_mask; i++) {
420 if (!(tag_mask & (1UL << i)))
422 tag = tag_offset + i;
423 prefetch(tags->static_rqs[tag]);
424 tag_mask &= ~(1UL << i);
425 rq = blk_mq_rq_ctx_init(data, tags, tag);
426 rq_list_add(data->cached_rq, rq);
429 if (!(data->rq_flags & RQF_SCHED_TAGS))
430 blk_mq_add_active_requests(data->hctx, nr);
431 /* caller already holds a reference, add for remainder */
432 percpu_ref_get_many(&data->q->q_usage_counter, nr - 1);
435 return rq_list_pop(data->cached_rq);
438 static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
440 struct request_queue *q = data->q;
441 u64 alloc_time_ns = 0;
445 /* alloc_time includes depth and tag waits */
446 if (blk_queue_rq_alloc_time(q))
447 alloc_time_ns = ktime_get_ns();
449 if (data->cmd_flags & REQ_NOWAIT)
450 data->flags |= BLK_MQ_REQ_NOWAIT;
454 * All requests use scheduler tags when an I/O scheduler is
455 * enabled for the queue.
457 data->rq_flags |= RQF_SCHED_TAGS;
460 * Flush/passthrough requests are special and go directly to the
463 if ((data->cmd_flags & REQ_OP_MASK) != REQ_OP_FLUSH &&
464 !blk_op_is_passthrough(data->cmd_flags)) {
465 struct elevator_mq_ops *ops = &q->elevator->type->ops;
467 WARN_ON_ONCE(data->flags & BLK_MQ_REQ_RESERVED);
469 data->rq_flags |= RQF_USE_SCHED;
470 if (ops->limit_depth)
471 ops->limit_depth(data->cmd_flags, data);
476 data->ctx = blk_mq_get_ctx(q);
477 data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx);
478 if (!(data->rq_flags & RQF_SCHED_TAGS))
479 blk_mq_tag_busy(data->hctx);
481 if (data->flags & BLK_MQ_REQ_RESERVED)
482 data->rq_flags |= RQF_RESV;
485 * Try batched alloc if we want more than 1 tag.
487 if (data->nr_tags > 1) {
488 rq = __blk_mq_alloc_requests_batch(data);
490 blk_mq_rq_time_init(rq, alloc_time_ns);
497 * Waiting allocations only fail because of an inactive hctx. In that
498 * case just retry the hctx assignment and tag allocation as CPU hotplug
499 * should have migrated us to an online CPU by now.
501 tag = blk_mq_get_tag(data);
502 if (tag == BLK_MQ_NO_TAG) {
503 if (data->flags & BLK_MQ_REQ_NOWAIT)
506 * Give up the CPU and sleep for a random short time to
507 * ensure that thread using a realtime scheduling class
508 * are migrated off the CPU, and thus off the hctx that
515 if (!(data->rq_flags & RQF_SCHED_TAGS))
516 blk_mq_inc_active_requests(data->hctx);
517 rq = blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag);
518 blk_mq_rq_time_init(rq, alloc_time_ns);
522 static struct request *blk_mq_rq_cache_fill(struct request_queue *q,
523 struct blk_plug *plug,
525 blk_mq_req_flags_t flags)
527 struct blk_mq_alloc_data data = {
531 .nr_tags = plug->nr_ios,
532 .cached_rq = &plug->cached_rq,
536 if (blk_queue_enter(q, flags))
541 rq = __blk_mq_alloc_requests(&data);
547 static struct request *blk_mq_alloc_cached_request(struct request_queue *q,
549 blk_mq_req_flags_t flags)
551 struct blk_plug *plug = current->plug;
557 if (rq_list_empty(plug->cached_rq)) {
558 if (plug->nr_ios == 1)
560 rq = blk_mq_rq_cache_fill(q, plug, opf, flags);
564 rq = rq_list_peek(&plug->cached_rq);
565 if (!rq || rq->q != q)
568 if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type)
570 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf))
573 plug->cached_rq = rq_list_next(rq);
574 blk_mq_rq_time_init(rq, 0);
578 INIT_LIST_HEAD(&rq->queuelist);
582 struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf,
583 blk_mq_req_flags_t flags)
587 rq = blk_mq_alloc_cached_request(q, opf, flags);
589 struct blk_mq_alloc_data data = {
597 ret = blk_queue_enter(q, flags);
601 rq = __blk_mq_alloc_requests(&data);
606 rq->__sector = (sector_t) -1;
607 rq->bio = rq->biotail = NULL;
611 return ERR_PTR(-EWOULDBLOCK);
613 EXPORT_SYMBOL(blk_mq_alloc_request);
615 struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
616 blk_opf_t opf, blk_mq_req_flags_t flags, unsigned int hctx_idx)
618 struct blk_mq_alloc_data data = {
624 u64 alloc_time_ns = 0;
630 /* alloc_time includes depth and tag waits */
631 if (blk_queue_rq_alloc_time(q))
632 alloc_time_ns = ktime_get_ns();
635 * If the tag allocator sleeps we could get an allocation for a
636 * different hardware context. No need to complicate the low level
637 * allocator for this for the rare use case of a command tied to
640 if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)) ||
641 WARN_ON_ONCE(!(flags & BLK_MQ_REQ_RESERVED)))
642 return ERR_PTR(-EINVAL);
644 if (hctx_idx >= q->nr_hw_queues)
645 return ERR_PTR(-EIO);
647 ret = blk_queue_enter(q, flags);
652 * Check if the hardware context is actually mapped to anything.
653 * If not tell the caller that it should skip this queue.
656 data.hctx = xa_load(&q->hctx_table, hctx_idx);
657 if (!blk_mq_hw_queue_mapped(data.hctx))
659 cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
660 if (cpu >= nr_cpu_ids)
662 data.ctx = __blk_mq_get_ctx(q, cpu);
665 data.rq_flags |= RQF_SCHED_TAGS;
667 blk_mq_tag_busy(data.hctx);
669 if (flags & BLK_MQ_REQ_RESERVED)
670 data.rq_flags |= RQF_RESV;
673 tag = blk_mq_get_tag(&data);
674 if (tag == BLK_MQ_NO_TAG)
676 if (!(data.rq_flags & RQF_SCHED_TAGS))
677 blk_mq_inc_active_requests(data.hctx);
678 rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag);
679 blk_mq_rq_time_init(rq, alloc_time_ns);
681 rq->__sector = (sector_t) -1;
682 rq->bio = rq->biotail = NULL;
689 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
691 static void blk_mq_finish_request(struct request *rq)
693 struct request_queue *q = rq->q;
695 if (rq->rq_flags & RQF_USE_SCHED) {
696 q->elevator->type->ops.finish_request(rq);
698 * For postflush request that may need to be
699 * completed twice, we should clear this flag
700 * to avoid double finish_request() on the rq.
702 rq->rq_flags &= ~RQF_USE_SCHED;
706 static void __blk_mq_free_request(struct request *rq)
708 struct request_queue *q = rq->q;
709 struct blk_mq_ctx *ctx = rq->mq_ctx;
710 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
711 const int sched_tag = rq->internal_tag;
713 blk_crypto_free_request(rq);
714 blk_pm_mark_last_busy(rq);
717 if (rq->tag != BLK_MQ_NO_TAG) {
718 blk_mq_dec_active_requests(hctx);
719 blk_mq_put_tag(hctx->tags, ctx, rq->tag);
721 if (sched_tag != BLK_MQ_NO_TAG)
722 blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
723 blk_mq_sched_restart(hctx);
727 void blk_mq_free_request(struct request *rq)
729 struct request_queue *q = rq->q;
731 blk_mq_finish_request(rq);
733 if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
734 laptop_io_completion(q->disk->bdi);
738 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
739 if (req_ref_put_and_test(rq))
740 __blk_mq_free_request(rq);
742 EXPORT_SYMBOL_GPL(blk_mq_free_request);
744 void blk_mq_free_plug_rqs(struct blk_plug *plug)
748 while ((rq = rq_list_pop(&plug->cached_rq)) != NULL)
749 blk_mq_free_request(rq);
752 void blk_dump_rq_flags(struct request *rq, char *msg)
754 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
755 rq->q->disk ? rq->q->disk->disk_name : "?",
756 (__force unsigned long long) rq->cmd_flags);
758 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
759 (unsigned long long)blk_rq_pos(rq),
760 blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
761 printk(KERN_INFO " bio %p, biotail %p, len %u\n",
762 rq->bio, rq->biotail, blk_rq_bytes(rq));
764 EXPORT_SYMBOL(blk_dump_rq_flags);
766 static void req_bio_endio(struct request *rq, struct bio *bio,
767 unsigned int nbytes, blk_status_t error)
769 if (unlikely(error)) {
770 bio->bi_status = error;
771 } else if (req_op(rq) == REQ_OP_ZONE_APPEND) {
773 * Partial zone append completions cannot be supported as the
774 * BIO fragments may end up not being written sequentially.
776 if (bio->bi_iter.bi_size != nbytes)
777 bio->bi_status = BLK_STS_IOERR;
779 bio->bi_iter.bi_sector = rq->__sector;
782 bio_advance(bio, nbytes);
784 if (unlikely(rq->rq_flags & RQF_QUIET))
785 bio_set_flag(bio, BIO_QUIET);
786 /* don't actually finish bio if it's part of flush sequence */
787 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
791 static void blk_account_io_completion(struct request *req, unsigned int bytes)
793 if (req->part && blk_do_io_stat(req)) {
794 const int sgrp = op_stat_group(req_op(req));
797 part_stat_add(req->part, sectors[sgrp], bytes >> 9);
802 static void blk_print_req_error(struct request *req, blk_status_t status)
804 printk_ratelimited(KERN_ERR
805 "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
806 "phys_seg %u prio class %u\n",
807 blk_status_to_str(status),
808 req->q->disk ? req->q->disk->disk_name : "?",
809 blk_rq_pos(req), (__force u32)req_op(req),
810 blk_op_str(req_op(req)),
811 (__force u32)(req->cmd_flags & ~REQ_OP_MASK),
812 req->nr_phys_segments,
813 IOPRIO_PRIO_CLASS(req->ioprio));
817 * Fully end IO on a request. Does not support partial completions, or
820 static void blk_complete_request(struct request *req)
822 const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0;
823 int total_bytes = blk_rq_bytes(req);
824 struct bio *bio = req->bio;
826 trace_block_rq_complete(req, BLK_STS_OK, total_bytes);
831 #ifdef CONFIG_BLK_DEV_INTEGRITY
832 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ)
833 req->q->integrity.profile->complete_fn(req, total_bytes);
837 * Upper layers may call blk_crypto_evict_key() anytime after the last
838 * bio_endio(). Therefore, the keyslot must be released before that.
840 blk_crypto_rq_put_keyslot(req);
842 blk_account_io_completion(req, total_bytes);
845 struct bio *next = bio->bi_next;
847 /* Completion has already been traced */
848 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
850 if (req_op(req) == REQ_OP_ZONE_APPEND)
851 bio->bi_iter.bi_sector = req->__sector;
859 * Reset counters so that the request stacking driver
860 * can find how many bytes remain in the request
870 * blk_update_request - Complete multiple bytes without completing the request
871 * @req: the request being processed
872 * @error: block status code
873 * @nr_bytes: number of bytes to complete for @req
876 * Ends I/O on a number of bytes attached to @req, but doesn't complete
877 * the request structure even if @req doesn't have leftover.
878 * If @req has leftover, sets it up for the next range of segments.
880 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
881 * %false return from this function.
884 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
885 * except in the consistency check at the end of this function.
888 * %false - this request doesn't have any more data
889 * %true - this request has more data
891 bool blk_update_request(struct request *req, blk_status_t error,
892 unsigned int nr_bytes)
896 trace_block_rq_complete(req, error, nr_bytes);
901 #ifdef CONFIG_BLK_DEV_INTEGRITY
902 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
904 req->q->integrity.profile->complete_fn(req, nr_bytes);
908 * Upper layers may call blk_crypto_evict_key() anytime after the last
909 * bio_endio(). Therefore, the keyslot must be released before that.
911 if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req))
912 __blk_crypto_rq_put_keyslot(req);
914 if (unlikely(error && !blk_rq_is_passthrough(req) &&
915 !(req->rq_flags & RQF_QUIET)) &&
916 !test_bit(GD_DEAD, &req->q->disk->state)) {
917 blk_print_req_error(req, error);
918 trace_block_rq_error(req, error, nr_bytes);
921 blk_account_io_completion(req, nr_bytes);
925 struct bio *bio = req->bio;
926 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
928 if (bio_bytes == bio->bi_iter.bi_size)
929 req->bio = bio->bi_next;
931 /* Completion has already been traced */
932 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
933 req_bio_endio(req, bio, bio_bytes, error);
935 total_bytes += bio_bytes;
936 nr_bytes -= bio_bytes;
947 * Reset counters so that the request stacking driver
948 * can find how many bytes remain in the request
955 req->__data_len -= total_bytes;
957 /* update sector only for requests with clear definition of sector */
958 if (!blk_rq_is_passthrough(req))
959 req->__sector += total_bytes >> 9;
961 /* mixed attributes always follow the first bio */
962 if (req->rq_flags & RQF_MIXED_MERGE) {
963 req->cmd_flags &= ~REQ_FAILFAST_MASK;
964 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
967 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
969 * If total number of sectors is less than the first segment
970 * size, something has gone terribly wrong.
972 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
973 blk_dump_rq_flags(req, "request botched");
974 req->__data_len = blk_rq_cur_bytes(req);
977 /* recalculate the number of segments */
978 req->nr_phys_segments = blk_recalc_rq_segments(req);
983 EXPORT_SYMBOL_GPL(blk_update_request);
985 static inline void blk_account_io_done(struct request *req, u64 now)
987 trace_block_io_done(req);
990 * Account IO completion. flush_rq isn't accounted as a
991 * normal IO on queueing nor completion. Accounting the
992 * containing request is enough.
994 if (blk_do_io_stat(req) && req->part &&
995 !(req->rq_flags & RQF_FLUSH_SEQ)) {
996 const int sgrp = op_stat_group(req_op(req));
999 update_io_ticks(req->part, jiffies, true);
1000 part_stat_inc(req->part, ios[sgrp]);
1001 part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
1006 static inline void blk_account_io_start(struct request *req)
1008 trace_block_io_start(req);
1010 if (blk_do_io_stat(req)) {
1012 * All non-passthrough requests are created from a bio with one
1013 * exception: when a flush command that is part of a flush sequence
1014 * generated by the state machine in blk-flush.c is cloned onto the
1015 * lower device by dm-multipath we can get here without a bio.
1018 req->part = req->bio->bi_bdev;
1020 req->part = req->q->disk->part0;
1023 update_io_ticks(req->part, jiffies, false);
1028 static inline void __blk_mq_end_request_acct(struct request *rq, u64 now)
1030 if (rq->rq_flags & RQF_STATS)
1031 blk_stat_add(rq, now);
1033 blk_mq_sched_completed_request(rq, now);
1034 blk_account_io_done(rq, now);
1037 inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
1039 if (blk_mq_need_time_stamp(rq))
1040 __blk_mq_end_request_acct(rq, ktime_get_ns());
1042 blk_mq_finish_request(rq);
1045 rq_qos_done(rq->q, rq);
1046 if (rq->end_io(rq, error) == RQ_END_IO_FREE)
1047 blk_mq_free_request(rq);
1049 blk_mq_free_request(rq);
1052 EXPORT_SYMBOL(__blk_mq_end_request);
1054 void blk_mq_end_request(struct request *rq, blk_status_t error)
1056 if (blk_update_request(rq, error, blk_rq_bytes(rq)))
1058 __blk_mq_end_request(rq, error);
1060 EXPORT_SYMBOL(blk_mq_end_request);
1062 #define TAG_COMP_BATCH 32
1064 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
1065 int *tag_array, int nr_tags)
1067 struct request_queue *q = hctx->queue;
1069 blk_mq_sub_active_requests(hctx, nr_tags);
1071 blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
1072 percpu_ref_put_many(&q->q_usage_counter, nr_tags);
1075 void blk_mq_end_request_batch(struct io_comp_batch *iob)
1077 int tags[TAG_COMP_BATCH], nr_tags = 0;
1078 struct blk_mq_hw_ctx *cur_hctx = NULL;
1083 now = ktime_get_ns();
1085 while ((rq = rq_list_pop(&iob->req_list)) != NULL) {
1087 prefetch(rq->rq_next);
1089 blk_complete_request(rq);
1091 __blk_mq_end_request_acct(rq, now);
1093 blk_mq_finish_request(rq);
1095 rq_qos_done(rq->q, rq);
1098 * If end_io handler returns NONE, then it still has
1099 * ownership of the request.
1101 if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
1104 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1105 if (!req_ref_put_and_test(rq))
1108 blk_crypto_free_request(rq);
1109 blk_pm_mark_last_busy(rq);
1111 if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) {
1113 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1115 cur_hctx = rq->mq_hctx;
1117 tags[nr_tags++] = rq->tag;
1121 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1123 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch);
1125 static void blk_complete_reqs(struct llist_head *list)
1127 struct llist_node *entry = llist_reverse_order(llist_del_all(list));
1128 struct request *rq, *next;
1130 llist_for_each_entry_safe(rq, next, entry, ipi_list)
1131 rq->q->mq_ops->complete(rq);
1134 static __latent_entropy void blk_done_softirq(struct softirq_action *h)
1136 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
1139 static int blk_softirq_cpu_dead(unsigned int cpu)
1141 blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
1145 static void __blk_mq_complete_request_remote(void *data)
1147 __raise_softirq_irqoff(BLOCK_SOFTIRQ);
1150 static inline bool blk_mq_complete_need_ipi(struct request *rq)
1152 int cpu = raw_smp_processor_id();
1154 if (!IS_ENABLED(CONFIG_SMP) ||
1155 !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
1158 * With force threaded interrupts enabled, raising softirq from an SMP
1159 * function call will always result in waking the ksoftirqd thread.
1160 * This is probably worse than completing the request on a different
1163 if (force_irqthreads())
1166 /* same CPU or cache domain? Complete locally */
1167 if (cpu == rq->mq_ctx->cpu ||
1168 (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
1169 cpus_share_cache(cpu, rq->mq_ctx->cpu)))
1172 /* don't try to IPI to an offline CPU */
1173 return cpu_online(rq->mq_ctx->cpu);
1176 static void blk_mq_complete_send_ipi(struct request *rq)
1180 cpu = rq->mq_ctx->cpu;
1181 if (llist_add(&rq->ipi_list, &per_cpu(blk_cpu_done, cpu)))
1182 smp_call_function_single_async(cpu, &per_cpu(blk_cpu_csd, cpu));
1185 static void blk_mq_raise_softirq(struct request *rq)
1187 struct llist_head *list;
1190 list = this_cpu_ptr(&blk_cpu_done);
1191 if (llist_add(&rq->ipi_list, list))
1192 raise_softirq(BLOCK_SOFTIRQ);
1196 bool blk_mq_complete_request_remote(struct request *rq)
1198 WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
1201 * For request which hctx has only one ctx mapping,
1202 * or a polled request, always complete locally,
1203 * it's pointless to redirect the completion.
1205 if ((rq->mq_hctx->nr_ctx == 1 &&
1206 rq->mq_ctx->cpu == raw_smp_processor_id()) ||
1207 rq->cmd_flags & REQ_POLLED)
1210 if (blk_mq_complete_need_ipi(rq)) {
1211 blk_mq_complete_send_ipi(rq);
1215 if (rq->q->nr_hw_queues == 1) {
1216 blk_mq_raise_softirq(rq);
1221 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
1224 * blk_mq_complete_request - end I/O on a request
1225 * @rq: the request being processed
1228 * Complete a request by scheduling the ->complete_rq operation.
1230 void blk_mq_complete_request(struct request *rq)
1232 if (!blk_mq_complete_request_remote(rq))
1233 rq->q->mq_ops->complete(rq);
1235 EXPORT_SYMBOL(blk_mq_complete_request);
1238 * blk_mq_start_request - Start processing a request
1239 * @rq: Pointer to request to be started
1241 * Function used by device drivers to notify the block layer that a request
1242 * is going to be processed now, so blk layer can do proper initializations
1243 * such as starting the timeout timer.
1245 void blk_mq_start_request(struct request *rq)
1247 struct request_queue *q = rq->q;
1249 trace_block_rq_issue(rq);
1251 if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
1252 rq->io_start_time_ns = ktime_get_ns();
1253 rq->stats_sectors = blk_rq_sectors(rq);
1254 rq->rq_flags |= RQF_STATS;
1255 rq_qos_issue(q, rq);
1258 WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
1261 WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
1262 rq->mq_hctx->tags->rqs[rq->tag] = rq;
1264 #ifdef CONFIG_BLK_DEV_INTEGRITY
1265 if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
1266 q->integrity.profile->prepare_fn(rq);
1268 if (rq->bio && rq->bio->bi_opf & REQ_POLLED)
1269 WRITE_ONCE(rq->bio->bi_cookie, rq->mq_hctx->queue_num);
1271 EXPORT_SYMBOL(blk_mq_start_request);
1274 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
1275 * queues. This is important for md arrays to benefit from merging
1278 static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
1280 if (plug->multiple_queues)
1281 return BLK_MAX_REQUEST_COUNT * 2;
1282 return BLK_MAX_REQUEST_COUNT;
1285 static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
1287 struct request *last = rq_list_peek(&plug->mq_list);
1289 if (!plug->rq_count) {
1290 trace_block_plug(rq->q);
1291 } else if (plug->rq_count >= blk_plug_max_rq_count(plug) ||
1292 (!blk_queue_nomerges(rq->q) &&
1293 blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
1294 blk_mq_flush_plug_list(plug, false);
1296 trace_block_plug(rq->q);
1299 if (!plug->multiple_queues && last && last->q != rq->q)
1300 plug->multiple_queues = true;
1302 * Any request allocated from sched tags can't be issued to
1303 * ->queue_rqs() directly
1305 if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS))
1306 plug->has_elevator = true;
1308 rq_list_add(&plug->mq_list, rq);
1313 * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
1314 * @rq: request to insert
1315 * @at_head: insert request at head or tail of queue
1318 * Insert a fully prepared request at the back of the I/O scheduler queue
1319 * for execution. Don't wait for completion.
1322 * This function will invoke @done directly if the queue is dead.
1324 void blk_execute_rq_nowait(struct request *rq, bool at_head)
1326 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1328 WARN_ON(irqs_disabled());
1329 WARN_ON(!blk_rq_is_passthrough(rq));
1331 blk_account_io_start(rq);
1334 * As plugging can be enabled for passthrough requests on a zoned
1335 * device, directly accessing the plug instead of using blk_mq_plug()
1336 * should not have any consequences.
1338 if (current->plug && !at_head) {
1339 blk_add_rq_to_plug(current->plug, rq);
1343 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1344 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
1346 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
1348 struct blk_rq_wait {
1349 struct completion done;
1353 static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret)
1355 struct blk_rq_wait *wait = rq->end_io_data;
1358 complete(&wait->done);
1359 return RQ_END_IO_NONE;
1362 bool blk_rq_is_poll(struct request *rq)
1366 if (rq->mq_hctx->type != HCTX_TYPE_POLL)
1370 EXPORT_SYMBOL_GPL(blk_rq_is_poll);
1372 static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
1375 blk_hctx_poll(rq->q, rq->mq_hctx, NULL, 0);
1377 } while (!completion_done(wait));
1381 * blk_execute_rq - insert a request into queue for execution
1382 * @rq: request to insert
1383 * @at_head: insert request at head or tail of queue
1386 * Insert a fully prepared request at the back of the I/O scheduler queue
1387 * for execution and wait for completion.
1388 * Return: The blk_status_t result provided to blk_mq_end_request().
1390 blk_status_t blk_execute_rq(struct request *rq, bool at_head)
1392 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1393 struct blk_rq_wait wait = {
1394 .done = COMPLETION_INITIALIZER_ONSTACK(wait.done),
1397 WARN_ON(irqs_disabled());
1398 WARN_ON(!blk_rq_is_passthrough(rq));
1400 rq->end_io_data = &wait;
1401 rq->end_io = blk_end_sync_rq;
1403 blk_account_io_start(rq);
1404 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1405 blk_mq_run_hw_queue(hctx, false);
1407 if (blk_rq_is_poll(rq)) {
1408 blk_rq_poll_completion(rq, &wait.done);
1411 * Prevent hang_check timer from firing at us during very long
1414 unsigned long hang_check = sysctl_hung_task_timeout_secs;
1417 while (!wait_for_completion_io_timeout(&wait.done,
1418 hang_check * (HZ/2)))
1421 wait_for_completion_io(&wait.done);
1426 EXPORT_SYMBOL(blk_execute_rq);
1428 static void __blk_mq_requeue_request(struct request *rq)
1430 struct request_queue *q = rq->q;
1432 blk_mq_put_driver_tag(rq);
1434 trace_block_rq_requeue(rq);
1435 rq_qos_requeue(q, rq);
1437 if (blk_mq_request_started(rq)) {
1438 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1439 rq->rq_flags &= ~RQF_TIMED_OUT;
1443 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
1445 struct request_queue *q = rq->q;
1446 unsigned long flags;
1448 __blk_mq_requeue_request(rq);
1450 /* this request will be re-inserted to io scheduler queue */
1451 blk_mq_sched_requeue_request(rq);
1453 spin_lock_irqsave(&q->requeue_lock, flags);
1454 list_add_tail(&rq->queuelist, &q->requeue_list);
1455 spin_unlock_irqrestore(&q->requeue_lock, flags);
1457 if (kick_requeue_list)
1458 blk_mq_kick_requeue_list(q);
1460 EXPORT_SYMBOL(blk_mq_requeue_request);
1462 static void blk_mq_requeue_work(struct work_struct *work)
1464 struct request_queue *q =
1465 container_of(work, struct request_queue, requeue_work.work);
1467 LIST_HEAD(flush_list);
1470 spin_lock_irq(&q->requeue_lock);
1471 list_splice_init(&q->requeue_list, &rq_list);
1472 list_splice_init(&q->flush_list, &flush_list);
1473 spin_unlock_irq(&q->requeue_lock);
1475 while (!list_empty(&rq_list)) {
1476 rq = list_entry(rq_list.next, struct request, queuelist);
1478 * If RQF_DONTPREP ist set, the request has been started by the
1479 * driver already and might have driver-specific data allocated
1480 * already. Insert it into the hctx dispatch list to avoid
1481 * block layer merges for the request.
1483 if (rq->rq_flags & RQF_DONTPREP) {
1484 list_del_init(&rq->queuelist);
1485 blk_mq_request_bypass_insert(rq, 0);
1487 list_del_init(&rq->queuelist);
1488 blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
1492 while (!list_empty(&flush_list)) {
1493 rq = list_entry(flush_list.next, struct request, queuelist);
1494 list_del_init(&rq->queuelist);
1495 blk_mq_insert_request(rq, 0);
1498 blk_mq_run_hw_queues(q, false);
1501 void blk_mq_kick_requeue_list(struct request_queue *q)
1503 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
1505 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
1507 void blk_mq_delay_kick_requeue_list(struct request_queue *q,
1508 unsigned long msecs)
1510 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
1511 msecs_to_jiffies(msecs));
1513 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
1515 static bool blk_mq_rq_inflight(struct request *rq, void *priv)
1518 * If we find a request that isn't idle we know the queue is busy
1519 * as it's checked in the iter.
1520 * Return false to stop the iteration.
1522 if (blk_mq_request_started(rq)) {
1532 bool blk_mq_queue_inflight(struct request_queue *q)
1536 blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
1539 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
1541 static void blk_mq_rq_timed_out(struct request *req)
1543 req->rq_flags |= RQF_TIMED_OUT;
1544 if (req->q->mq_ops->timeout) {
1545 enum blk_eh_timer_return ret;
1547 ret = req->q->mq_ops->timeout(req);
1548 if (ret == BLK_EH_DONE)
1550 WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
1556 struct blk_expired_data {
1557 bool has_timedout_rq;
1559 unsigned long timeout_start;
1562 static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired)
1564 unsigned long deadline;
1566 if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
1568 if (rq->rq_flags & RQF_TIMED_OUT)
1571 deadline = READ_ONCE(rq->deadline);
1572 if (time_after_eq(expired->timeout_start, deadline))
1575 if (expired->next == 0)
1576 expired->next = deadline;
1577 else if (time_after(expired->next, deadline))
1578 expired->next = deadline;
1582 void blk_mq_put_rq_ref(struct request *rq)
1584 if (is_flush_rq(rq)) {
1585 if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
1586 blk_mq_free_request(rq);
1587 } else if (req_ref_put_and_test(rq)) {
1588 __blk_mq_free_request(rq);
1592 static bool blk_mq_check_expired(struct request *rq, void *priv)
1594 struct blk_expired_data *expired = priv;
1597 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1598 * be reallocated underneath the timeout handler's processing, then
1599 * the expire check is reliable. If the request is not expired, then
1600 * it was completed and reallocated as a new request after returning
1601 * from blk_mq_check_expired().
1603 if (blk_mq_req_expired(rq, expired)) {
1604 expired->has_timedout_rq = true;
1610 static bool blk_mq_handle_expired(struct request *rq, void *priv)
1612 struct blk_expired_data *expired = priv;
1614 if (blk_mq_req_expired(rq, expired))
1615 blk_mq_rq_timed_out(rq);
1619 static void blk_mq_timeout_work(struct work_struct *work)
1621 struct request_queue *q =
1622 container_of(work, struct request_queue, timeout_work);
1623 struct blk_expired_data expired = {
1624 .timeout_start = jiffies,
1626 struct blk_mq_hw_ctx *hctx;
1629 /* A deadlock might occur if a request is stuck requiring a
1630 * timeout at the same time a queue freeze is waiting
1631 * completion, since the timeout code would not be able to
1632 * acquire the queue reference here.
1634 * That's why we don't use blk_queue_enter here; instead, we use
1635 * percpu_ref_tryget directly, because we need to be able to
1636 * obtain a reference even in the short window between the queue
1637 * starting to freeze, by dropping the first reference in
1638 * blk_freeze_queue_start, and the moment the last request is
1639 * consumed, marked by the instant q_usage_counter reaches
1642 if (!percpu_ref_tryget(&q->q_usage_counter))
1645 /* check if there is any timed-out request */
1646 blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
1647 if (expired.has_timedout_rq) {
1649 * Before walking tags, we must ensure any submit started
1650 * before the current time has finished. Since the submit
1651 * uses srcu or rcu, wait for a synchronization point to
1652 * ensure all running submits have finished
1654 blk_mq_wait_quiesce_done(q->tag_set);
1657 blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired);
1660 if (expired.next != 0) {
1661 mod_timer(&q->timeout, expired.next);
1664 * Request timeouts are handled as a forward rolling timer. If
1665 * we end up here it means that no requests are pending and
1666 * also that no request has been pending for a while. Mark
1667 * each hctx as idle.
1669 queue_for_each_hw_ctx(q, hctx, i) {
1670 /* the hctx may be unmapped, so check it here */
1671 if (blk_mq_hw_queue_mapped(hctx))
1672 blk_mq_tag_idle(hctx);
1678 struct flush_busy_ctx_data {
1679 struct blk_mq_hw_ctx *hctx;
1680 struct list_head *list;
1683 static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
1685 struct flush_busy_ctx_data *flush_data = data;
1686 struct blk_mq_hw_ctx *hctx = flush_data->hctx;
1687 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1688 enum hctx_type type = hctx->type;
1690 spin_lock(&ctx->lock);
1691 list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
1692 sbitmap_clear_bit(sb, bitnr);
1693 spin_unlock(&ctx->lock);
1698 * Process software queues that have been marked busy, splicing them
1699 * to the for-dispatch
1701 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
1703 struct flush_busy_ctx_data data = {
1708 sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
1710 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
1712 struct dispatch_rq_data {
1713 struct blk_mq_hw_ctx *hctx;
1717 static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
1720 struct dispatch_rq_data *dispatch_data = data;
1721 struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
1722 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1723 enum hctx_type type = hctx->type;
1725 spin_lock(&ctx->lock);
1726 if (!list_empty(&ctx->rq_lists[type])) {
1727 dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
1728 list_del_init(&dispatch_data->rq->queuelist);
1729 if (list_empty(&ctx->rq_lists[type]))
1730 sbitmap_clear_bit(sb, bitnr);
1732 spin_unlock(&ctx->lock);
1734 return !dispatch_data->rq;
1737 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
1738 struct blk_mq_ctx *start)
1740 unsigned off = start ? start->index_hw[hctx->type] : 0;
1741 struct dispatch_rq_data data = {
1746 __sbitmap_for_each_set(&hctx->ctx_map, off,
1747 dispatch_rq_from_ctx, &data);
1752 bool __blk_mq_alloc_driver_tag(struct request *rq)
1754 struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
1755 unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
1758 blk_mq_tag_busy(rq->mq_hctx);
1760 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
1761 bt = &rq->mq_hctx->tags->breserved_tags;
1764 if (!hctx_may_queue(rq->mq_hctx, bt))
1768 tag = __sbitmap_queue_get(bt);
1769 if (tag == BLK_MQ_NO_TAG)
1772 rq->tag = tag + tag_offset;
1773 blk_mq_inc_active_requests(rq->mq_hctx);
1777 static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
1778 int flags, void *key)
1780 struct blk_mq_hw_ctx *hctx;
1782 hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
1784 spin_lock(&hctx->dispatch_wait_lock);
1785 if (!list_empty(&wait->entry)) {
1786 struct sbitmap_queue *sbq;
1788 list_del_init(&wait->entry);
1789 sbq = &hctx->tags->bitmap_tags;
1790 atomic_dec(&sbq->ws_active);
1792 spin_unlock(&hctx->dispatch_wait_lock);
1794 blk_mq_run_hw_queue(hctx, true);
1799 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1800 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1801 * restart. For both cases, take care to check the condition again after
1802 * marking us as waiting.
1804 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
1807 struct sbitmap_queue *sbq;
1808 struct wait_queue_head *wq;
1809 wait_queue_entry_t *wait;
1812 if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
1813 !(blk_mq_is_shared_tags(hctx->flags))) {
1814 blk_mq_sched_mark_restart_hctx(hctx);
1817 * It's possible that a tag was freed in the window between the
1818 * allocation failure and adding the hardware queue to the wait
1821 * Don't clear RESTART here, someone else could have set it.
1822 * At most this will cost an extra queue run.
1824 return blk_mq_get_driver_tag(rq);
1827 wait = &hctx->dispatch_wait;
1828 if (!list_empty_careful(&wait->entry))
1831 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag))
1832 sbq = &hctx->tags->breserved_tags;
1834 sbq = &hctx->tags->bitmap_tags;
1835 wq = &bt_wait_ptr(sbq, hctx)->wait;
1837 spin_lock_irq(&wq->lock);
1838 spin_lock(&hctx->dispatch_wait_lock);
1839 if (!list_empty(&wait->entry)) {
1840 spin_unlock(&hctx->dispatch_wait_lock);
1841 spin_unlock_irq(&wq->lock);
1845 atomic_inc(&sbq->ws_active);
1846 wait->flags &= ~WQ_FLAG_EXCLUSIVE;
1847 __add_wait_queue(wq, wait);
1850 * It's possible that a tag was freed in the window between the
1851 * allocation failure and adding the hardware queue to the wait
1854 ret = blk_mq_get_driver_tag(rq);
1856 spin_unlock(&hctx->dispatch_wait_lock);
1857 spin_unlock_irq(&wq->lock);
1862 * We got a tag, remove ourselves from the wait queue to ensure
1863 * someone else gets the wakeup.
1865 list_del_init(&wait->entry);
1866 atomic_dec(&sbq->ws_active);
1867 spin_unlock(&hctx->dispatch_wait_lock);
1868 spin_unlock_irq(&wq->lock);
1873 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1874 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1876 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1877 * - EWMA is one simple way to compute running average value
1878 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1879 * - take 4 as factor for avoiding to get too small(0) result, and this
1880 * factor doesn't matter because EWMA decreases exponentially
1882 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
1886 ewma = hctx->dispatch_busy;
1891 ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
1893 ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
1894 ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
1896 hctx->dispatch_busy = ewma;
1899 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1901 static void blk_mq_handle_dev_resource(struct request *rq,
1902 struct list_head *list)
1904 list_add(&rq->queuelist, list);
1905 __blk_mq_requeue_request(rq);
1908 static void blk_mq_handle_zone_resource(struct request *rq,
1909 struct list_head *zone_list)
1912 * If we end up here it is because we cannot dispatch a request to a
1913 * specific zone due to LLD level zone-write locking or other zone
1914 * related resource not being available. In this case, set the request
1915 * aside in zone_list for retrying it later.
1917 list_add(&rq->queuelist, zone_list);
1918 __blk_mq_requeue_request(rq);
1921 enum prep_dispatch {
1923 PREP_DISPATCH_NO_TAG,
1924 PREP_DISPATCH_NO_BUDGET,
1927 static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
1930 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1931 int budget_token = -1;
1934 budget_token = blk_mq_get_dispatch_budget(rq->q);
1935 if (budget_token < 0) {
1936 blk_mq_put_driver_tag(rq);
1937 return PREP_DISPATCH_NO_BUDGET;
1939 blk_mq_set_rq_budget_token(rq, budget_token);
1942 if (!blk_mq_get_driver_tag(rq)) {
1944 * The initial allocation attempt failed, so we need to
1945 * rerun the hardware queue when a tag is freed. The
1946 * waitqueue takes care of that. If the queue is run
1947 * before we add this entry back on the dispatch list,
1948 * we'll re-run it below.
1950 if (!blk_mq_mark_tag_wait(hctx, rq)) {
1952 * All budgets not got from this function will be put
1953 * together during handling partial dispatch
1956 blk_mq_put_dispatch_budget(rq->q, budget_token);
1957 return PREP_DISPATCH_NO_TAG;
1961 return PREP_DISPATCH_OK;
1964 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1965 static void blk_mq_release_budgets(struct request_queue *q,
1966 struct list_head *list)
1970 list_for_each_entry(rq, list, queuelist) {
1971 int budget_token = blk_mq_get_rq_budget_token(rq);
1973 if (budget_token >= 0)
1974 blk_mq_put_dispatch_budget(q, budget_token);
1979 * blk_mq_commit_rqs will notify driver using bd->last that there is no
1980 * more requests. (See comment in struct blk_mq_ops for commit_rqs for
1982 * Attention, we should explicitly call this in unusual cases:
1983 * 1) did not queue everything initially scheduled to queue
1984 * 2) the last attempt to queue a request failed
1986 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued,
1989 if (hctx->queue->mq_ops->commit_rqs && queued) {
1990 trace_block_unplug(hctx->queue, queued, !from_schedule);
1991 hctx->queue->mq_ops->commit_rqs(hctx);
1996 * Returns true if we did some work AND can potentially do more.
1998 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
1999 unsigned int nr_budgets)
2001 enum prep_dispatch prep;
2002 struct request_queue *q = hctx->queue;
2005 blk_status_t ret = BLK_STS_OK;
2006 LIST_HEAD(zone_list);
2007 bool needs_resource = false;
2009 if (list_empty(list))
2013 * Now process all the entries, sending them to the driver.
2017 struct blk_mq_queue_data bd;
2019 rq = list_first_entry(list, struct request, queuelist);
2021 WARN_ON_ONCE(hctx != rq->mq_hctx);
2022 prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
2023 if (prep != PREP_DISPATCH_OK)
2026 list_del_init(&rq->queuelist);
2029 bd.last = list_empty(list);
2032 * once the request is queued to lld, no need to cover the
2037 ret = q->mq_ops->queue_rq(hctx, &bd);
2042 case BLK_STS_RESOURCE:
2043 needs_resource = true;
2045 case BLK_STS_DEV_RESOURCE:
2046 blk_mq_handle_dev_resource(rq, list);
2048 case BLK_STS_ZONE_RESOURCE:
2050 * Move the request to zone_list and keep going through
2051 * the dispatch list to find more requests the drive can
2054 blk_mq_handle_zone_resource(rq, &zone_list);
2055 needs_resource = true;
2058 blk_mq_end_request(rq, ret);
2060 } while (!list_empty(list));
2062 if (!list_empty(&zone_list))
2063 list_splice_tail_init(&zone_list, list);
2065 /* If we didn't flush the entire list, we could have told the driver
2066 * there was more coming, but that turned out to be a lie.
2068 if (!list_empty(list) || ret != BLK_STS_OK)
2069 blk_mq_commit_rqs(hctx, queued, false);
2072 * Any items that need requeuing? Stuff them into hctx->dispatch,
2073 * that is where we will continue on next queue run.
2075 if (!list_empty(list)) {
2077 /* For non-shared tags, the RESTART check will suffice */
2078 bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
2079 ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||
2080 blk_mq_is_shared_tags(hctx->flags));
2083 blk_mq_release_budgets(q, list);
2085 spin_lock(&hctx->lock);
2086 list_splice_tail_init(list, &hctx->dispatch);
2087 spin_unlock(&hctx->lock);
2090 * Order adding requests to hctx->dispatch and checking
2091 * SCHED_RESTART flag. The pair of this smp_mb() is the one
2092 * in blk_mq_sched_restart(). Avoid restart code path to
2093 * miss the new added requests to hctx->dispatch, meantime
2094 * SCHED_RESTART is observed here.
2099 * If SCHED_RESTART was set by the caller of this function and
2100 * it is no longer set that means that it was cleared by another
2101 * thread and hence that a queue rerun is needed.
2103 * If 'no_tag' is set, that means that we failed getting
2104 * a driver tag with an I/O scheduler attached. If our dispatch
2105 * waitqueue is no longer active, ensure that we run the queue
2106 * AFTER adding our entries back to the list.
2108 * If no I/O scheduler has been configured it is possible that
2109 * the hardware queue got stopped and restarted before requests
2110 * were pushed back onto the dispatch list. Rerun the queue to
2111 * avoid starvation. Notes:
2112 * - blk_mq_run_hw_queue() checks whether or not a queue has
2113 * been stopped before rerunning a queue.
2114 * - Some but not all block drivers stop a queue before
2115 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
2118 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
2119 * bit is set, run queue after a delay to avoid IO stalls
2120 * that could otherwise occur if the queue is idle. We'll do
2121 * similar if we couldn't get budget or couldn't lock a zone
2122 * and SCHED_RESTART is set.
2124 needs_restart = blk_mq_sched_needs_restart(hctx);
2125 if (prep == PREP_DISPATCH_NO_BUDGET)
2126 needs_resource = true;
2127 if (!needs_restart ||
2128 (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
2129 blk_mq_run_hw_queue(hctx, true);
2130 else if (needs_resource)
2131 blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
2133 blk_mq_update_dispatch_busy(hctx, true);
2137 blk_mq_update_dispatch_busy(hctx, false);
2141 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
2143 int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
2145 if (cpu >= nr_cpu_ids)
2146 cpu = cpumask_first(hctx->cpumask);
2151 * It'd be great if the workqueue API had a way to pass
2152 * in a mask and had some smarts for more clever placement.
2153 * For now we just round-robin here, switching for every
2154 * BLK_MQ_CPU_WORK_BATCH queued items.
2156 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
2159 int next_cpu = hctx->next_cpu;
2161 if (hctx->queue->nr_hw_queues == 1)
2162 return WORK_CPU_UNBOUND;
2164 if (--hctx->next_cpu_batch <= 0) {
2166 next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
2168 if (next_cpu >= nr_cpu_ids)
2169 next_cpu = blk_mq_first_mapped_cpu(hctx);
2170 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
2174 * Do unbound schedule if we can't find a online CPU for this hctx,
2175 * and it should only happen in the path of handling CPU DEAD.
2177 if (!cpu_online(next_cpu)) {
2184 * Make sure to re-select CPU next time once after CPUs
2185 * in hctx->cpumask become online again.
2187 hctx->next_cpu = next_cpu;
2188 hctx->next_cpu_batch = 1;
2189 return WORK_CPU_UNBOUND;
2192 hctx->next_cpu = next_cpu;
2197 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
2198 * @hctx: Pointer to the hardware queue to run.
2199 * @msecs: Milliseconds of delay to wait before running the queue.
2201 * Run a hardware queue asynchronously with a delay of @msecs.
2203 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
2205 if (unlikely(blk_mq_hctx_stopped(hctx)))
2207 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
2208 msecs_to_jiffies(msecs));
2210 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
2213 * blk_mq_run_hw_queue - Start to run a hardware queue.
2214 * @hctx: Pointer to the hardware queue to run.
2215 * @async: If we want to run the queue asynchronously.
2217 * Check if the request queue is not in a quiesced state and if there are
2218 * pending requests to be sent. If this is true, run the queue to send requests
2221 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2226 * We can't run the queue inline with interrupts disabled.
2228 WARN_ON_ONCE(!async && in_interrupt());
2230 might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING);
2233 * When queue is quiesced, we may be switching io scheduler, or
2234 * updating nr_hw_queues, or other things, and we can't run queue
2235 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
2237 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
2240 __blk_mq_run_dispatch_ops(hctx->queue, false,
2241 need_run = !blk_queue_quiesced(hctx->queue) &&
2242 blk_mq_hctx_has_pending(hctx));
2247 if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) {
2248 blk_mq_delay_run_hw_queue(hctx, 0);
2252 blk_mq_run_dispatch_ops(hctx->queue,
2253 blk_mq_sched_dispatch_requests(hctx));
2255 EXPORT_SYMBOL(blk_mq_run_hw_queue);
2258 * Return prefered queue to dispatch from (if any) for non-mq aware IO
2261 static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
2263 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
2265 * If the IO scheduler does not respect hardware queues when
2266 * dispatching, we just don't bother with multiple HW queues and
2267 * dispatch from hctx for the current CPU since running multiple queues
2268 * just causes lock contention inside the scheduler and pointless cache
2271 struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT];
2273 if (!blk_mq_hctx_stopped(hctx))
2279 * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
2280 * @q: Pointer to the request queue to run.
2281 * @async: If we want to run the queue asynchronously.
2283 void blk_mq_run_hw_queues(struct request_queue *q, bool async)
2285 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2289 if (blk_queue_sq_sched(q))
2290 sq_hctx = blk_mq_get_sq_hctx(q);
2291 queue_for_each_hw_ctx(q, hctx, i) {
2292 if (blk_mq_hctx_stopped(hctx))
2295 * Dispatch from this hctx either if there's no hctx preferred
2296 * by IO scheduler or if it has requests that bypass the
2299 if (!sq_hctx || sq_hctx == hctx ||
2300 !list_empty_careful(&hctx->dispatch))
2301 blk_mq_run_hw_queue(hctx, async);
2304 EXPORT_SYMBOL(blk_mq_run_hw_queues);
2307 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
2308 * @q: Pointer to the request queue to run.
2309 * @msecs: Milliseconds of delay to wait before running the queues.
2311 void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
2313 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2317 if (blk_queue_sq_sched(q))
2318 sq_hctx = blk_mq_get_sq_hctx(q);
2319 queue_for_each_hw_ctx(q, hctx, i) {
2320 if (blk_mq_hctx_stopped(hctx))
2323 * If there is already a run_work pending, leave the
2324 * pending delay untouched. Otherwise, a hctx can stall
2325 * if another hctx is re-delaying the other's work
2326 * before the work executes.
2328 if (delayed_work_pending(&hctx->run_work))
2331 * Dispatch from this hctx either if there's no hctx preferred
2332 * by IO scheduler or if it has requests that bypass the
2335 if (!sq_hctx || sq_hctx == hctx ||
2336 !list_empty_careful(&hctx->dispatch))
2337 blk_mq_delay_run_hw_queue(hctx, msecs);
2340 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
2343 * This function is often used for pausing .queue_rq() by driver when
2344 * there isn't enough resource or some conditions aren't satisfied, and
2345 * BLK_STS_RESOURCE is usually returned.
2347 * We do not guarantee that dispatch can be drained or blocked
2348 * after blk_mq_stop_hw_queue() returns. Please use
2349 * blk_mq_quiesce_queue() for that requirement.
2351 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
2353 cancel_delayed_work(&hctx->run_work);
2355 set_bit(BLK_MQ_S_STOPPED, &hctx->state);
2357 EXPORT_SYMBOL(blk_mq_stop_hw_queue);
2360 * This function is often used for pausing .queue_rq() by driver when
2361 * there isn't enough resource or some conditions aren't satisfied, and
2362 * BLK_STS_RESOURCE is usually returned.
2364 * We do not guarantee that dispatch can be drained or blocked
2365 * after blk_mq_stop_hw_queues() returns. Please use
2366 * blk_mq_quiesce_queue() for that requirement.
2368 void blk_mq_stop_hw_queues(struct request_queue *q)
2370 struct blk_mq_hw_ctx *hctx;
2373 queue_for_each_hw_ctx(q, hctx, i)
2374 blk_mq_stop_hw_queue(hctx);
2376 EXPORT_SYMBOL(blk_mq_stop_hw_queues);
2378 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
2380 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2382 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
2384 EXPORT_SYMBOL(blk_mq_start_hw_queue);
2386 void blk_mq_start_hw_queues(struct request_queue *q)
2388 struct blk_mq_hw_ctx *hctx;
2391 queue_for_each_hw_ctx(q, hctx, i)
2392 blk_mq_start_hw_queue(hctx);
2394 EXPORT_SYMBOL(blk_mq_start_hw_queues);
2396 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2398 if (!blk_mq_hctx_stopped(hctx))
2401 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2402 blk_mq_run_hw_queue(hctx, async);
2404 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
2406 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
2408 struct blk_mq_hw_ctx *hctx;
2411 queue_for_each_hw_ctx(q, hctx, i)
2412 blk_mq_start_stopped_hw_queue(hctx, async ||
2413 (hctx->flags & BLK_MQ_F_BLOCKING));
2415 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
2417 static void blk_mq_run_work_fn(struct work_struct *work)
2419 struct blk_mq_hw_ctx *hctx =
2420 container_of(work, struct blk_mq_hw_ctx, run_work.work);
2422 blk_mq_run_dispatch_ops(hctx->queue,
2423 blk_mq_sched_dispatch_requests(hctx));
2427 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2428 * @rq: Pointer to request to be inserted.
2429 * @flags: BLK_MQ_INSERT_*
2431 * Should only be used carefully, when the caller knows we want to
2432 * bypass a potential IO scheduler on the target device.
2434 static void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags)
2436 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2438 spin_lock(&hctx->lock);
2439 if (flags & BLK_MQ_INSERT_AT_HEAD)
2440 list_add(&rq->queuelist, &hctx->dispatch);
2442 list_add_tail(&rq->queuelist, &hctx->dispatch);
2443 spin_unlock(&hctx->lock);
2446 static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
2447 struct blk_mq_ctx *ctx, struct list_head *list,
2448 bool run_queue_async)
2451 enum hctx_type type = hctx->type;
2454 * Try to issue requests directly if the hw queue isn't busy to save an
2455 * extra enqueue & dequeue to the sw queue.
2457 if (!hctx->dispatch_busy && !run_queue_async) {
2458 blk_mq_run_dispatch_ops(hctx->queue,
2459 blk_mq_try_issue_list_directly(hctx, list));
2460 if (list_empty(list))
2465 * preemption doesn't flush plug list, so it's possible ctx->cpu is
2468 list_for_each_entry(rq, list, queuelist) {
2469 BUG_ON(rq->mq_ctx != ctx);
2470 trace_block_rq_insert(rq);
2471 if (rq->cmd_flags & REQ_NOWAIT)
2472 run_queue_async = true;
2475 spin_lock(&ctx->lock);
2476 list_splice_tail_init(list, &ctx->rq_lists[type]);
2477 blk_mq_hctx_mark_pending(hctx, ctx);
2478 spin_unlock(&ctx->lock);
2480 blk_mq_run_hw_queue(hctx, run_queue_async);
2483 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
2485 struct request_queue *q = rq->q;
2486 struct blk_mq_ctx *ctx = rq->mq_ctx;
2487 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2489 if (blk_rq_is_passthrough(rq)) {
2491 * Passthrough request have to be added to hctx->dispatch
2492 * directly. The device may be in a situation where it can't
2493 * handle FS request, and always returns BLK_STS_RESOURCE for
2494 * them, which gets them added to hctx->dispatch.
2496 * If a passthrough request is required to unblock the queues,
2497 * and it is added to the scheduler queue, there is no chance to
2498 * dispatch it given we prioritize requests in hctx->dispatch.
2500 blk_mq_request_bypass_insert(rq, flags);
2501 } else if (req_op(rq) == REQ_OP_FLUSH) {
2503 * Firstly normal IO request is inserted to scheduler queue or
2504 * sw queue, meantime we add flush request to dispatch queue(
2505 * hctx->dispatch) directly and there is at most one in-flight
2506 * flush request for each hw queue, so it doesn't matter to add
2507 * flush request to tail or front of the dispatch queue.
2509 * Secondly in case of NCQ, flush request belongs to non-NCQ
2510 * command, and queueing it will fail when there is any
2511 * in-flight normal IO request(NCQ command). When adding flush
2512 * rq to the front of hctx->dispatch, it is easier to introduce
2513 * extra time to flush rq's latency because of S_SCHED_RESTART
2514 * compared with adding to the tail of dispatch queue, then
2515 * chance of flush merge is increased, and less flush requests
2516 * will be issued to controller. It is observed that ~10% time
2517 * is saved in blktests block/004 on disk attached to AHCI/NCQ
2518 * drive when adding flush rq to the front of hctx->dispatch.
2520 * Simply queue flush rq to the front of hctx->dispatch so that
2521 * intensive flush workloads can benefit in case of NCQ HW.
2523 blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD);
2524 } else if (q->elevator) {
2527 WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG);
2529 list_add(&rq->queuelist, &list);
2530 q->elevator->type->ops.insert_requests(hctx, &list, flags);
2532 trace_block_rq_insert(rq);
2534 spin_lock(&ctx->lock);
2535 if (flags & BLK_MQ_INSERT_AT_HEAD)
2536 list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]);
2538 list_add_tail(&rq->queuelist,
2539 &ctx->rq_lists[hctx->type]);
2540 blk_mq_hctx_mark_pending(hctx, ctx);
2541 spin_unlock(&ctx->lock);
2545 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
2546 unsigned int nr_segs)
2550 if (bio->bi_opf & REQ_RAHEAD)
2551 rq->cmd_flags |= REQ_FAILFAST_MASK;
2553 rq->__sector = bio->bi_iter.bi_sector;
2554 blk_rq_bio_prep(rq, bio, nr_segs);
2556 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2557 err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
2560 blk_account_io_start(rq);
2563 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
2564 struct request *rq, bool last)
2566 struct request_queue *q = rq->q;
2567 struct blk_mq_queue_data bd = {
2574 * For OK queue, we are done. For error, caller may kill it.
2575 * Any other error (busy), just add it to our list as we
2576 * previously would have done.
2578 ret = q->mq_ops->queue_rq(hctx, &bd);
2581 blk_mq_update_dispatch_busy(hctx, false);
2583 case BLK_STS_RESOURCE:
2584 case BLK_STS_DEV_RESOURCE:
2585 blk_mq_update_dispatch_busy(hctx, true);
2586 __blk_mq_requeue_request(rq);
2589 blk_mq_update_dispatch_busy(hctx, false);
2596 static bool blk_mq_get_budget_and_tag(struct request *rq)
2600 budget_token = blk_mq_get_dispatch_budget(rq->q);
2601 if (budget_token < 0)
2603 blk_mq_set_rq_budget_token(rq, budget_token);
2604 if (!blk_mq_get_driver_tag(rq)) {
2605 blk_mq_put_dispatch_budget(rq->q, budget_token);
2612 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2613 * @hctx: Pointer of the associated hardware queue.
2614 * @rq: Pointer to request to be sent.
2616 * If the device has enough resources to accept a new request now, send the
2617 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2618 * we can try send it another time in the future. Requests inserted at this
2619 * queue have higher priority.
2621 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
2626 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2627 blk_mq_insert_request(rq, 0);
2631 if ((rq->rq_flags & RQF_USE_SCHED) || !blk_mq_get_budget_and_tag(rq)) {
2632 blk_mq_insert_request(rq, 0);
2633 blk_mq_run_hw_queue(hctx, rq->cmd_flags & REQ_NOWAIT);
2637 ret = __blk_mq_issue_directly(hctx, rq, true);
2641 case BLK_STS_RESOURCE:
2642 case BLK_STS_DEV_RESOURCE:
2643 blk_mq_request_bypass_insert(rq, 0);
2644 blk_mq_run_hw_queue(hctx, false);
2647 blk_mq_end_request(rq, ret);
2652 static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
2654 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2656 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2657 blk_mq_insert_request(rq, 0);
2661 if (!blk_mq_get_budget_and_tag(rq))
2662 return BLK_STS_RESOURCE;
2663 return __blk_mq_issue_directly(hctx, rq, last);
2666 static void blk_mq_plug_issue_direct(struct blk_plug *plug)
2668 struct blk_mq_hw_ctx *hctx = NULL;
2671 blk_status_t ret = BLK_STS_OK;
2673 while ((rq = rq_list_pop(&plug->mq_list))) {
2674 bool last = rq_list_empty(plug->mq_list);
2676 if (hctx != rq->mq_hctx) {
2678 blk_mq_commit_rqs(hctx, queued, false);
2684 ret = blk_mq_request_issue_directly(rq, last);
2689 case BLK_STS_RESOURCE:
2690 case BLK_STS_DEV_RESOURCE:
2691 blk_mq_request_bypass_insert(rq, 0);
2692 blk_mq_run_hw_queue(hctx, false);
2695 blk_mq_end_request(rq, ret);
2701 if (ret != BLK_STS_OK)
2702 blk_mq_commit_rqs(hctx, queued, false);
2705 static void __blk_mq_flush_plug_list(struct request_queue *q,
2706 struct blk_plug *plug)
2708 if (blk_queue_quiesced(q))
2710 q->mq_ops->queue_rqs(&plug->mq_list);
2713 static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
2715 struct blk_mq_hw_ctx *this_hctx = NULL;
2716 struct blk_mq_ctx *this_ctx = NULL;
2717 struct request *requeue_list = NULL;
2718 struct request **requeue_lastp = &requeue_list;
2719 unsigned int depth = 0;
2720 bool is_passthrough = false;
2724 struct request *rq = rq_list_pop(&plug->mq_list);
2727 this_hctx = rq->mq_hctx;
2728 this_ctx = rq->mq_ctx;
2729 is_passthrough = blk_rq_is_passthrough(rq);
2730 } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx ||
2731 is_passthrough != blk_rq_is_passthrough(rq)) {
2732 rq_list_add_tail(&requeue_lastp, rq);
2735 list_add(&rq->queuelist, &list);
2737 } while (!rq_list_empty(plug->mq_list));
2739 plug->mq_list = requeue_list;
2740 trace_block_unplug(this_hctx->queue, depth, !from_sched);
2742 percpu_ref_get(&this_hctx->queue->q_usage_counter);
2743 /* passthrough requests should never be issued to the I/O scheduler */
2744 if (is_passthrough) {
2745 spin_lock(&this_hctx->lock);
2746 list_splice_tail_init(&list, &this_hctx->dispatch);
2747 spin_unlock(&this_hctx->lock);
2748 blk_mq_run_hw_queue(this_hctx, from_sched);
2749 } else if (this_hctx->queue->elevator) {
2750 this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
2752 blk_mq_run_hw_queue(this_hctx, from_sched);
2754 blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched);
2756 percpu_ref_put(&this_hctx->queue->q_usage_counter);
2759 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
2764 * We may have been called recursively midway through handling
2765 * plug->mq_list via a schedule() in the driver's queue_rq() callback.
2766 * To avoid mq_list changing under our feet, clear rq_count early and
2767 * bail out specifically if rq_count is 0 rather than checking
2768 * whether the mq_list is empty.
2770 if (plug->rq_count == 0)
2774 if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
2775 struct request_queue *q;
2777 rq = rq_list_peek(&plug->mq_list);
2781 * Peek first request and see if we have a ->queue_rqs() hook.
2782 * If we do, we can dispatch the whole plug list in one go. We
2783 * already know at this point that all requests belong to the
2784 * same queue, caller must ensure that's the case.
2786 if (q->mq_ops->queue_rqs) {
2787 blk_mq_run_dispatch_ops(q,
2788 __blk_mq_flush_plug_list(q, plug));
2789 if (rq_list_empty(plug->mq_list))
2793 blk_mq_run_dispatch_ops(q,
2794 blk_mq_plug_issue_direct(plug));
2795 if (rq_list_empty(plug->mq_list))
2800 blk_mq_dispatch_plug_list(plug, from_schedule);
2801 } while (!rq_list_empty(plug->mq_list));
2804 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
2805 struct list_head *list)
2808 blk_status_t ret = BLK_STS_OK;
2810 while (!list_empty(list)) {
2811 struct request *rq = list_first_entry(list, struct request,
2814 list_del_init(&rq->queuelist);
2815 ret = blk_mq_request_issue_directly(rq, list_empty(list));
2820 case BLK_STS_RESOURCE:
2821 case BLK_STS_DEV_RESOURCE:
2822 blk_mq_request_bypass_insert(rq, 0);
2823 if (list_empty(list))
2824 blk_mq_run_hw_queue(hctx, false);
2827 blk_mq_end_request(rq, ret);
2833 if (ret != BLK_STS_OK)
2834 blk_mq_commit_rqs(hctx, queued, false);
2837 static bool blk_mq_attempt_bio_merge(struct request_queue *q,
2838 struct bio *bio, unsigned int nr_segs)
2840 if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
2841 if (blk_attempt_plug_merge(q, bio, nr_segs))
2843 if (blk_mq_sched_bio_merge(q, bio, nr_segs))
2849 static struct request *blk_mq_get_new_requests(struct request_queue *q,
2850 struct blk_plug *plug,
2854 struct blk_mq_alloc_data data = {
2857 .cmd_flags = bio->bi_opf,
2861 if (unlikely(bio_queue_enter(bio)))
2864 if (blk_mq_attempt_bio_merge(q, bio, nsegs))
2867 rq_qos_throttle(q, bio);
2870 data.nr_tags = plug->nr_ios;
2872 data.cached_rq = &plug->cached_rq;
2875 rq = __blk_mq_alloc_requests(&data);
2878 rq_qos_cleanup(q, bio);
2879 if (bio->bi_opf & REQ_NOWAIT)
2880 bio_wouldblock_error(bio);
2886 static inline struct request *blk_mq_get_cached_request(struct request_queue *q,
2887 struct blk_plug *plug, struct bio **bio, unsigned int nsegs)
2890 enum hctx_type type, hctx_type;
2894 rq = rq_list_peek(&plug->cached_rq);
2895 if (!rq || rq->q != q)
2898 if (blk_mq_attempt_bio_merge(q, *bio, nsegs)) {
2903 type = blk_mq_get_hctx_type((*bio)->bi_opf);
2904 hctx_type = rq->mq_hctx->type;
2905 if (type != hctx_type &&
2906 !(type == HCTX_TYPE_READ && hctx_type == HCTX_TYPE_DEFAULT))
2908 if (op_is_flush(rq->cmd_flags) != op_is_flush((*bio)->bi_opf))
2912 * If any qos ->throttle() end up blocking, we will have flushed the
2913 * plug and hence killed the cached_rq list as well. Pop this entry
2914 * before we throttle.
2916 plug->cached_rq = rq_list_next(rq);
2917 rq_qos_throttle(q, *bio);
2919 blk_mq_rq_time_init(rq, 0);
2920 rq->cmd_flags = (*bio)->bi_opf;
2921 INIT_LIST_HEAD(&rq->queuelist);
2925 static void bio_set_ioprio(struct bio *bio)
2927 /* Nobody set ioprio so far? Initialize it based on task's nice value */
2928 if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
2929 bio->bi_ioprio = get_current_ioprio();
2930 blkcg_set_ioprio(bio);
2934 * blk_mq_submit_bio - Create and send a request to block device.
2935 * @bio: Bio pointer.
2937 * Builds up a request structure from @q and @bio and send to the device. The
2938 * request may not be queued directly to hardware if:
2939 * * This request can be merged with another one
2940 * * We want to place request at plug queue for possible future merging
2941 * * There is an IO scheduler active at this queue
2943 * It will not queue the request if there is an error with the bio, or at the
2946 void blk_mq_submit_bio(struct bio *bio)
2948 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
2949 struct blk_plug *plug = blk_mq_plug(bio);
2950 const int is_sync = op_is_sync(bio->bi_opf);
2951 struct blk_mq_hw_ctx *hctx;
2953 unsigned int nr_segs = 1;
2956 bio = blk_queue_bounce(bio, q);
2957 if (bio_may_exceed_limits(bio, &q->limits)) {
2958 bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
2963 if (!bio_integrity_prep(bio))
2966 bio_set_ioprio(bio);
2968 rq = blk_mq_get_cached_request(q, plug, &bio, nr_segs);
2972 rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
2977 trace_block_getrq(bio);
2979 rq_qos_track(q, rq, bio);
2981 blk_mq_bio_to_request(rq, bio, nr_segs);
2983 ret = blk_crypto_rq_get_keyslot(rq);
2984 if (ret != BLK_STS_OK) {
2985 bio->bi_status = ret;
2987 blk_mq_free_request(rq);
2991 if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq))
2995 blk_add_rq_to_plug(plug, rq);
3000 if ((rq->rq_flags & RQF_USE_SCHED) ||
3001 (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) {
3002 blk_mq_insert_request(rq, 0);
3003 blk_mq_run_hw_queue(hctx, true);
3005 blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq));
3009 #ifdef CONFIG_BLK_MQ_STACKING
3011 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
3012 * @rq: the request being queued
3014 blk_status_t blk_insert_cloned_request(struct request *rq)
3016 struct request_queue *q = rq->q;
3017 unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
3018 unsigned int max_segments = blk_rq_get_max_segments(rq);
3021 if (blk_rq_sectors(rq) > max_sectors) {
3023 * SCSI device does not have a good way to return if
3024 * Write Same/Zero is actually supported. If a device rejects
3025 * a non-read/write command (discard, write same,etc.) the
3026 * low-level device driver will set the relevant queue limit to
3027 * 0 to prevent blk-lib from issuing more of the offending
3028 * operations. Commands queued prior to the queue limit being
3029 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
3030 * errors being propagated to upper layers.
3032 if (max_sectors == 0)
3033 return BLK_STS_NOTSUPP;
3035 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
3036 __func__, blk_rq_sectors(rq), max_sectors);
3037 return BLK_STS_IOERR;
3041 * The queue settings related to segment counting may differ from the
3044 rq->nr_phys_segments = blk_recalc_rq_segments(rq);
3045 if (rq->nr_phys_segments > max_segments) {
3046 printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n",
3047 __func__, rq->nr_phys_segments, max_segments);
3048 return BLK_STS_IOERR;
3051 if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq)))
3052 return BLK_STS_IOERR;
3054 ret = blk_crypto_rq_get_keyslot(rq);
3055 if (ret != BLK_STS_OK)
3058 blk_account_io_start(rq);
3061 * Since we have a scheduler attached on the top device,
3062 * bypass a potential scheduler on the bottom device for
3065 blk_mq_run_dispatch_ops(q,
3066 ret = blk_mq_request_issue_directly(rq, true));
3068 blk_account_io_done(rq, ktime_get_ns());
3071 EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
3074 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3075 * @rq: the clone request to be cleaned up
3078 * Free all bios in @rq for a cloned request.
3080 void blk_rq_unprep_clone(struct request *rq)
3084 while ((bio = rq->bio) != NULL) {
3085 rq->bio = bio->bi_next;
3090 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
3093 * blk_rq_prep_clone - Helper function to setup clone request
3094 * @rq: the request to be setup
3095 * @rq_src: original request to be cloned
3096 * @bs: bio_set that bios for clone are allocated from
3097 * @gfp_mask: memory allocation mask for bio
3098 * @bio_ctr: setup function to be called for each clone bio.
3099 * Returns %0 for success, non %0 for failure.
3100 * @data: private data to be passed to @bio_ctr
3103 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3104 * Also, pages which the original bios are pointing to are not copied
3105 * and the cloned bios just point same pages.
3106 * So cloned bios must be completed before original bios, which means
3107 * the caller must complete @rq before @rq_src.
3109 int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
3110 struct bio_set *bs, gfp_t gfp_mask,
3111 int (*bio_ctr)(struct bio *, struct bio *, void *),
3114 struct bio *bio, *bio_src;
3119 __rq_for_each_bio(bio_src, rq_src) {
3120 bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask,
3125 if (bio_ctr && bio_ctr(bio, bio_src, data))
3129 rq->biotail->bi_next = bio;
3132 rq->bio = rq->biotail = bio;
3137 /* Copy attributes of the original request to the clone request. */
3138 rq->__sector = blk_rq_pos(rq_src);
3139 rq->__data_len = blk_rq_bytes(rq_src);
3140 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
3141 rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
3142 rq->special_vec = rq_src->special_vec;
3144 rq->nr_phys_segments = rq_src->nr_phys_segments;
3145 rq->ioprio = rq_src->ioprio;
3147 if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
3155 blk_rq_unprep_clone(rq);
3159 EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3160 #endif /* CONFIG_BLK_MQ_STACKING */
3163 * Steal bios from a request and add them to a bio list.
3164 * The request must not have been partially completed before.
3166 void blk_steal_bios(struct bio_list *list, struct request *rq)
3170 list->tail->bi_next = rq->bio;
3172 list->head = rq->bio;
3173 list->tail = rq->biotail;
3181 EXPORT_SYMBOL_GPL(blk_steal_bios);
3183 static size_t order_to_size(unsigned int order)
3185 return (size_t)PAGE_SIZE << order;
3188 /* called before freeing request pool in @tags */
3189 static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
3190 struct blk_mq_tags *tags)
3193 unsigned long flags;
3196 * There is no need to clear mapping if driver tags is not initialized
3197 * or the mapping belongs to the driver tags.
3199 if (!drv_tags || drv_tags == tags)
3202 list_for_each_entry(page, &tags->page_list, lru) {
3203 unsigned long start = (unsigned long)page_address(page);
3204 unsigned long end = start + order_to_size(page->private);
3207 for (i = 0; i < drv_tags->nr_tags; i++) {
3208 struct request *rq = drv_tags->rqs[i];
3209 unsigned long rq_addr = (unsigned long)rq;
3211 if (rq_addr >= start && rq_addr < end) {
3212 WARN_ON_ONCE(req_ref_read(rq) != 0);
3213 cmpxchg(&drv_tags->rqs[i], rq, NULL);
3219 * Wait until all pending iteration is done.
3221 * Request reference is cleared and it is guaranteed to be observed
3222 * after the ->lock is released.
3224 spin_lock_irqsave(&drv_tags->lock, flags);
3225 spin_unlock_irqrestore(&drv_tags->lock, flags);
3228 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
3229 unsigned int hctx_idx)
3231 struct blk_mq_tags *drv_tags;
3234 if (list_empty(&tags->page_list))
3237 if (blk_mq_is_shared_tags(set->flags))
3238 drv_tags = set->shared_tags;
3240 drv_tags = set->tags[hctx_idx];
3242 if (tags->static_rqs && set->ops->exit_request) {
3245 for (i = 0; i < tags->nr_tags; i++) {
3246 struct request *rq = tags->static_rqs[i];
3250 set->ops->exit_request(set, rq, hctx_idx);
3251 tags->static_rqs[i] = NULL;
3255 blk_mq_clear_rq_mapping(drv_tags, tags);
3257 while (!list_empty(&tags->page_list)) {
3258 page = list_first_entry(&tags->page_list, struct page, lru);
3259 list_del_init(&page->lru);
3261 * Remove kmemleak object previously allocated in
3262 * blk_mq_alloc_rqs().
3264 kmemleak_free(page_address(page));
3265 __free_pages(page, page->private);
3269 void blk_mq_free_rq_map(struct blk_mq_tags *tags)
3273 kfree(tags->static_rqs);
3274 tags->static_rqs = NULL;
3276 blk_mq_free_tags(tags);
3279 static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set,
3280 unsigned int hctx_idx)
3284 for (i = 0; i < set->nr_maps; i++) {
3285 unsigned int start = set->map[i].queue_offset;
3286 unsigned int end = start + set->map[i].nr_queues;
3288 if (hctx_idx >= start && hctx_idx < end)
3292 if (i >= set->nr_maps)
3293 i = HCTX_TYPE_DEFAULT;
3298 static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set,
3299 unsigned int hctx_idx)
3301 enum hctx_type type = hctx_idx_to_type(set, hctx_idx);
3303 return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx);
3306 static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
3307 unsigned int hctx_idx,
3308 unsigned int nr_tags,
3309 unsigned int reserved_tags)
3311 int node = blk_mq_get_hctx_node(set, hctx_idx);
3312 struct blk_mq_tags *tags;
3314 if (node == NUMA_NO_NODE)
3315 node = set->numa_node;
3317 tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
3318 BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
3322 tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3323 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3328 tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3329 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3331 if (!tags->static_rqs)
3339 blk_mq_free_tags(tags);
3343 static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
3344 unsigned int hctx_idx, int node)
3348 if (set->ops->init_request) {
3349 ret = set->ops->init_request(set, rq, hctx_idx, node);
3354 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
3358 static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
3359 struct blk_mq_tags *tags,
3360 unsigned int hctx_idx, unsigned int depth)
3362 unsigned int i, j, entries_per_page, max_order = 4;
3363 int node = blk_mq_get_hctx_node(set, hctx_idx);
3364 size_t rq_size, left;
3366 if (node == NUMA_NO_NODE)
3367 node = set->numa_node;
3369 INIT_LIST_HEAD(&tags->page_list);
3372 * rq_size is the size of the request plus driver payload, rounded
3373 * to the cacheline size
3375 rq_size = round_up(sizeof(struct request) + set->cmd_size,
3377 left = rq_size * depth;
3379 for (i = 0; i < depth; ) {
3380 int this_order = max_order;
3385 while (this_order && left < order_to_size(this_order - 1))
3389 page = alloc_pages_node(node,
3390 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
3396 if (order_to_size(this_order) < rq_size)
3403 page->private = this_order;
3404 list_add_tail(&page->lru, &tags->page_list);
3406 p = page_address(page);
3408 * Allow kmemleak to scan these pages as they contain pointers
3409 * to additional allocations like via ops->init_request().
3411 kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
3412 entries_per_page = order_to_size(this_order) / rq_size;
3413 to_do = min(entries_per_page, depth - i);
3414 left -= to_do * rq_size;
3415 for (j = 0; j < to_do; j++) {
3416 struct request *rq = p;
3418 tags->static_rqs[i] = rq;
3419 if (blk_mq_init_request(set, rq, hctx_idx, node)) {
3420 tags->static_rqs[i] = NULL;
3431 blk_mq_free_rqs(set, tags, hctx_idx);
3435 struct rq_iter_data {
3436 struct blk_mq_hw_ctx *hctx;
3440 static bool blk_mq_has_request(struct request *rq, void *data)
3442 struct rq_iter_data *iter_data = data;
3444 if (rq->mq_hctx != iter_data->hctx)
3446 iter_data->has_rq = true;
3450 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
3452 struct blk_mq_tags *tags = hctx->sched_tags ?
3453 hctx->sched_tags : hctx->tags;
3454 struct rq_iter_data data = {
3458 blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
3462 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
3463 struct blk_mq_hw_ctx *hctx)
3465 if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu)
3467 if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
3472 static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
3474 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3475 struct blk_mq_hw_ctx, cpuhp_online);
3477 if (!cpumask_test_cpu(cpu, hctx->cpumask) ||
3478 !blk_mq_last_cpu_in_hctx(cpu, hctx))
3482 * Prevent new request from being allocated on the current hctx.
3484 * The smp_mb__after_atomic() Pairs with the implied barrier in
3485 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
3486 * seen once we return from the tag allocator.
3488 set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3489 smp_mb__after_atomic();
3492 * Try to grab a reference to the queue and wait for any outstanding
3493 * requests. If we could not grab a reference the queue has been
3494 * frozen and there are no requests.
3496 if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
3497 while (blk_mq_hctx_has_requests(hctx))
3499 percpu_ref_put(&hctx->queue->q_usage_counter);
3505 static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
3507 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3508 struct blk_mq_hw_ctx, cpuhp_online);
3510 if (cpumask_test_cpu(cpu, hctx->cpumask))
3511 clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3516 * 'cpu' is going away. splice any existing rq_list entries from this
3517 * software queue to the hw queue dispatch list, and ensure that it
3520 static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
3522 struct blk_mq_hw_ctx *hctx;
3523 struct blk_mq_ctx *ctx;
3525 enum hctx_type type;
3527 hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
3528 if (!cpumask_test_cpu(cpu, hctx->cpumask))
3531 ctx = __blk_mq_get_ctx(hctx->queue, cpu);
3534 spin_lock(&ctx->lock);
3535 if (!list_empty(&ctx->rq_lists[type])) {
3536 list_splice_init(&ctx->rq_lists[type], &tmp);
3537 blk_mq_hctx_clear_pending(hctx, ctx);
3539 spin_unlock(&ctx->lock);
3541 if (list_empty(&tmp))
3544 spin_lock(&hctx->lock);
3545 list_splice_tail_init(&tmp, &hctx->dispatch);
3546 spin_unlock(&hctx->lock);
3548 blk_mq_run_hw_queue(hctx, true);
3552 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
3554 if (!(hctx->flags & BLK_MQ_F_STACKING))
3555 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3556 &hctx->cpuhp_online);
3557 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
3562 * Before freeing hw queue, clearing the flush request reference in
3563 * tags->rqs[] for avoiding potential UAF.
3565 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
3566 unsigned int queue_depth, struct request *flush_rq)
3569 unsigned long flags;
3571 /* The hw queue may not be mapped yet */
3575 WARN_ON_ONCE(req_ref_read(flush_rq) != 0);
3577 for (i = 0; i < queue_depth; i++)
3578 cmpxchg(&tags->rqs[i], flush_rq, NULL);
3581 * Wait until all pending iteration is done.
3583 * Request reference is cleared and it is guaranteed to be observed
3584 * after the ->lock is released.
3586 spin_lock_irqsave(&tags->lock, flags);
3587 spin_unlock_irqrestore(&tags->lock, flags);
3590 /* hctx->ctxs will be freed in queue's release handler */
3591 static void blk_mq_exit_hctx(struct request_queue *q,
3592 struct blk_mq_tag_set *set,
3593 struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
3595 struct request *flush_rq = hctx->fq->flush_rq;
3597 if (blk_mq_hw_queue_mapped(hctx))
3598 blk_mq_tag_idle(hctx);
3600 if (blk_queue_init_done(q))
3601 blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
3602 set->queue_depth, flush_rq);
3603 if (set->ops->exit_request)
3604 set->ops->exit_request(set, flush_rq, hctx_idx);
3606 if (set->ops->exit_hctx)
3607 set->ops->exit_hctx(hctx, hctx_idx);
3609 blk_mq_remove_cpuhp(hctx);
3611 xa_erase(&q->hctx_table, hctx_idx);
3613 spin_lock(&q->unused_hctx_lock);
3614 list_add(&hctx->hctx_list, &q->unused_hctx_list);
3615 spin_unlock(&q->unused_hctx_lock);
3618 static void blk_mq_exit_hw_queues(struct request_queue *q,
3619 struct blk_mq_tag_set *set, int nr_queue)
3621 struct blk_mq_hw_ctx *hctx;
3624 queue_for_each_hw_ctx(q, hctx, i) {
3627 blk_mq_exit_hctx(q, set, hctx, i);
3631 static int blk_mq_init_hctx(struct request_queue *q,
3632 struct blk_mq_tag_set *set,
3633 struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
3635 hctx->queue_num = hctx_idx;
3637 if (!(hctx->flags & BLK_MQ_F_STACKING))
3638 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3639 &hctx->cpuhp_online);
3640 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
3642 hctx->tags = set->tags[hctx_idx];
3644 if (set->ops->init_hctx &&
3645 set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
3646 goto unregister_cpu_notifier;
3648 if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
3652 if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL))
3658 if (set->ops->exit_request)
3659 set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
3661 if (set->ops->exit_hctx)
3662 set->ops->exit_hctx(hctx, hctx_idx);
3663 unregister_cpu_notifier:
3664 blk_mq_remove_cpuhp(hctx);
3668 static struct blk_mq_hw_ctx *
3669 blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
3672 struct blk_mq_hw_ctx *hctx;
3673 gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
3675 hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node);
3677 goto fail_alloc_hctx;
3679 if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
3682 atomic_set(&hctx->nr_active, 0);
3683 if (node == NUMA_NO_NODE)
3684 node = set->numa_node;
3685 hctx->numa_node = node;
3687 INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
3688 spin_lock_init(&hctx->lock);
3689 INIT_LIST_HEAD(&hctx->dispatch);
3691 hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
3693 INIT_LIST_HEAD(&hctx->hctx_list);
3696 * Allocate space for all possible cpus to avoid allocation at
3699 hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
3704 if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
3705 gfp, node, false, false))
3709 spin_lock_init(&hctx->dispatch_wait_lock);
3710 init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
3711 INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
3713 hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
3717 blk_mq_hctx_kobj_init(hctx);
3722 sbitmap_free(&hctx->ctx_map);
3726 free_cpumask_var(hctx->cpumask);
3733 static void blk_mq_init_cpu_queues(struct request_queue *q,
3734 unsigned int nr_hw_queues)
3736 struct blk_mq_tag_set *set = q->tag_set;
3739 for_each_possible_cpu(i) {
3740 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
3741 struct blk_mq_hw_ctx *hctx;
3745 spin_lock_init(&__ctx->lock);
3746 for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
3747 INIT_LIST_HEAD(&__ctx->rq_lists[k]);
3752 * Set local node, IFF we have more than one hw queue. If
3753 * not, we remain on the home node of the device
3755 for (j = 0; j < set->nr_maps; j++) {
3756 hctx = blk_mq_map_queue_type(q, j, i);
3757 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
3758 hctx->numa_node = cpu_to_node(i);
3763 struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3764 unsigned int hctx_idx,
3767 struct blk_mq_tags *tags;
3770 tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags);
3774 ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
3776 blk_mq_free_rq_map(tags);
3783 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3786 if (blk_mq_is_shared_tags(set->flags)) {
3787 set->tags[hctx_idx] = set->shared_tags;
3792 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
3795 return set->tags[hctx_idx];
3798 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3799 struct blk_mq_tags *tags,
3800 unsigned int hctx_idx)
3803 blk_mq_free_rqs(set, tags, hctx_idx);
3804 blk_mq_free_rq_map(tags);
3808 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3809 unsigned int hctx_idx)
3811 if (!blk_mq_is_shared_tags(set->flags))
3812 blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx);
3814 set->tags[hctx_idx] = NULL;
3817 static void blk_mq_map_swqueue(struct request_queue *q)
3819 unsigned int j, hctx_idx;
3821 struct blk_mq_hw_ctx *hctx;
3822 struct blk_mq_ctx *ctx;
3823 struct blk_mq_tag_set *set = q->tag_set;
3825 queue_for_each_hw_ctx(q, hctx, i) {
3826 cpumask_clear(hctx->cpumask);
3828 hctx->dispatch_from = NULL;
3832 * Map software to hardware queues.
3834 * If the cpu isn't present, the cpu is mapped to first hctx.
3836 for_each_possible_cpu(i) {
3838 ctx = per_cpu_ptr(q->queue_ctx, i);
3839 for (j = 0; j < set->nr_maps; j++) {
3840 if (!set->map[j].nr_queues) {
3841 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3842 HCTX_TYPE_DEFAULT, i);
3845 hctx_idx = set->map[j].mq_map[i];
3846 /* unmapped hw queue can be remapped after CPU topo changed */
3847 if (!set->tags[hctx_idx] &&
3848 !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
3850 * If tags initialization fail for some hctx,
3851 * that hctx won't be brought online. In this
3852 * case, remap the current ctx to hctx[0] which
3853 * is guaranteed to always have tags allocated
3855 set->map[j].mq_map[i] = 0;
3858 hctx = blk_mq_map_queue_type(q, j, i);
3859 ctx->hctxs[j] = hctx;
3861 * If the CPU is already set in the mask, then we've
3862 * mapped this one already. This can happen if
3863 * devices share queues across queue maps.
3865 if (cpumask_test_cpu(i, hctx->cpumask))
3868 cpumask_set_cpu(i, hctx->cpumask);
3870 ctx->index_hw[hctx->type] = hctx->nr_ctx;
3871 hctx->ctxs[hctx->nr_ctx++] = ctx;
3874 * If the nr_ctx type overflows, we have exceeded the
3875 * amount of sw queues we can support.
3877 BUG_ON(!hctx->nr_ctx);
3880 for (; j < HCTX_MAX_TYPES; j++)
3881 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3882 HCTX_TYPE_DEFAULT, i);
3885 queue_for_each_hw_ctx(q, hctx, i) {
3887 * If no software queues are mapped to this hardware queue,
3888 * disable it and free the request entries.
3890 if (!hctx->nr_ctx) {
3891 /* Never unmap queue 0. We need it as a
3892 * fallback in case of a new remap fails
3896 __blk_mq_free_map_and_rqs(set, i);
3902 hctx->tags = set->tags[i];
3903 WARN_ON(!hctx->tags);
3906 * Set the map size to the number of mapped software queues.
3907 * This is more accurate and more efficient than looping
3908 * over all possibly mapped software queues.
3910 sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
3913 * Initialize batch roundrobin counts
3915 hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
3916 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
3921 * Caller needs to ensure that we're either frozen/quiesced, or that
3922 * the queue isn't live yet.
3924 static void queue_set_hctx_shared(struct request_queue *q, bool shared)
3926 struct blk_mq_hw_ctx *hctx;
3929 queue_for_each_hw_ctx(q, hctx, i) {
3931 hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3933 blk_mq_tag_idle(hctx);
3934 hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3939 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
3942 struct request_queue *q;
3944 lockdep_assert_held(&set->tag_list_lock);
3946 list_for_each_entry(q, &set->tag_list, tag_set_list) {
3947 blk_mq_freeze_queue(q);
3948 queue_set_hctx_shared(q, shared);
3949 blk_mq_unfreeze_queue(q);
3953 static void blk_mq_del_queue_tag_set(struct request_queue *q)
3955 struct blk_mq_tag_set *set = q->tag_set;
3957 mutex_lock(&set->tag_list_lock);
3958 list_del(&q->tag_set_list);
3959 if (list_is_singular(&set->tag_list)) {
3960 /* just transitioned to unshared */
3961 set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3962 /* update existing queue */
3963 blk_mq_update_tag_set_shared(set, false);
3965 mutex_unlock(&set->tag_list_lock);
3966 INIT_LIST_HEAD(&q->tag_set_list);
3969 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
3970 struct request_queue *q)
3972 mutex_lock(&set->tag_list_lock);
3975 * Check to see if we're transitioning to shared (from 1 to 2 queues).
3977 if (!list_empty(&set->tag_list) &&
3978 !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
3979 set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3980 /* update existing queue */
3981 blk_mq_update_tag_set_shared(set, true);
3983 if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
3984 queue_set_hctx_shared(q, true);
3985 list_add_tail(&q->tag_set_list, &set->tag_list);
3987 mutex_unlock(&set->tag_list_lock);
3990 /* All allocations will be freed in release handler of q->mq_kobj */
3991 static int blk_mq_alloc_ctxs(struct request_queue *q)
3993 struct blk_mq_ctxs *ctxs;
3996 ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
4000 ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
4001 if (!ctxs->queue_ctx)
4004 for_each_possible_cpu(cpu) {
4005 struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
4009 q->mq_kobj = &ctxs->kobj;
4010 q->queue_ctx = ctxs->queue_ctx;
4019 * It is the actual release handler for mq, but we do it from
4020 * request queue's release handler for avoiding use-after-free
4021 * and headache because q->mq_kobj shouldn't have been introduced,
4022 * but we can't group ctx/kctx kobj without it.
4024 void blk_mq_release(struct request_queue *q)
4026 struct blk_mq_hw_ctx *hctx, *next;
4029 queue_for_each_hw_ctx(q, hctx, i)
4030 WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
4032 /* all hctx are in .unused_hctx_list now */
4033 list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
4034 list_del_init(&hctx->hctx_list);
4035 kobject_put(&hctx->kobj);
4038 xa_destroy(&q->hctx_table);
4041 * release .mq_kobj and sw queue's kobject now because
4042 * both share lifetime with request queue.
4044 blk_mq_sysfs_deinit(q);
4047 static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
4050 struct request_queue *q;
4053 q = blk_alloc_queue(set->numa_node);
4055 return ERR_PTR(-ENOMEM);
4056 q->queuedata = queuedata;
4057 ret = blk_mq_init_allocated_queue(set, q);
4060 return ERR_PTR(ret);
4065 struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
4067 return blk_mq_init_queue_data(set, NULL);
4069 EXPORT_SYMBOL(blk_mq_init_queue);
4072 * blk_mq_destroy_queue - shutdown a request queue
4073 * @q: request queue to shutdown
4075 * This shuts down a request queue allocated by blk_mq_init_queue(). All future
4076 * requests will be failed with -ENODEV. The caller is responsible for dropping
4077 * the reference from blk_mq_init_queue() by calling blk_put_queue().
4079 * Context: can sleep
4081 void blk_mq_destroy_queue(struct request_queue *q)
4083 WARN_ON_ONCE(!queue_is_mq(q));
4084 WARN_ON_ONCE(blk_queue_registered(q));
4088 blk_queue_flag_set(QUEUE_FLAG_DYING, q);
4089 blk_queue_start_drain(q);
4090 blk_mq_freeze_queue_wait(q);
4093 blk_mq_cancel_work_sync(q);
4094 blk_mq_exit_queue(q);
4096 EXPORT_SYMBOL(blk_mq_destroy_queue);
4098 struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
4099 struct lock_class_key *lkclass)
4101 struct request_queue *q;
4102 struct gendisk *disk;
4104 q = blk_mq_init_queue_data(set, queuedata);
4108 disk = __alloc_disk_node(q, set->numa_node, lkclass);
4110 blk_mq_destroy_queue(q);
4112 return ERR_PTR(-ENOMEM);
4114 set_bit(GD_OWNS_QUEUE, &disk->state);
4117 EXPORT_SYMBOL(__blk_mq_alloc_disk);
4119 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
4120 struct lock_class_key *lkclass)
4122 struct gendisk *disk;
4124 if (!blk_get_queue(q))
4126 disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass);
4131 EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue);
4133 static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
4134 struct blk_mq_tag_set *set, struct request_queue *q,
4135 int hctx_idx, int node)
4137 struct blk_mq_hw_ctx *hctx = NULL, *tmp;
4139 /* reuse dead hctx first */
4140 spin_lock(&q->unused_hctx_lock);
4141 list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
4142 if (tmp->numa_node == node) {
4148 list_del_init(&hctx->hctx_list);
4149 spin_unlock(&q->unused_hctx_lock);
4152 hctx = blk_mq_alloc_hctx(q, set, node);
4156 if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
4162 kobject_put(&hctx->kobj);
4167 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
4168 struct request_queue *q)
4170 struct blk_mq_hw_ctx *hctx;
4173 /* protect against switching io scheduler */
4174 mutex_lock(&q->sysfs_lock);
4175 for (i = 0; i < set->nr_hw_queues; i++) {
4177 int node = blk_mq_get_hctx_node(set, i);
4178 struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i);
4181 old_node = old_hctx->numa_node;
4182 blk_mq_exit_hctx(q, set, old_hctx, i);
4185 if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) {
4188 pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
4190 hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node);
4191 WARN_ON_ONCE(!hctx);
4195 * Increasing nr_hw_queues fails. Free the newly allocated
4196 * hctxs and keep the previous q->nr_hw_queues.
4198 if (i != set->nr_hw_queues) {
4199 j = q->nr_hw_queues;
4202 q->nr_hw_queues = set->nr_hw_queues;
4205 xa_for_each_start(&q->hctx_table, j, hctx, j)
4206 blk_mq_exit_hctx(q, set, hctx, j);
4207 mutex_unlock(&q->sysfs_lock);
4210 static void blk_mq_update_poll_flag(struct request_queue *q)
4212 struct blk_mq_tag_set *set = q->tag_set;
4214 if (set->nr_maps > HCTX_TYPE_POLL &&
4215 set->map[HCTX_TYPE_POLL].nr_queues)
4216 blk_queue_flag_set(QUEUE_FLAG_POLL, q);
4218 blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
4221 int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
4222 struct request_queue *q)
4224 /* mark the queue as mq asap */
4225 q->mq_ops = set->ops;
4227 if (blk_mq_alloc_ctxs(q))
4230 /* init q->mq_kobj and sw queues' kobjects */
4231 blk_mq_sysfs_init(q);
4233 INIT_LIST_HEAD(&q->unused_hctx_list);
4234 spin_lock_init(&q->unused_hctx_lock);
4236 xa_init(&q->hctx_table);
4238 blk_mq_realloc_hw_ctxs(set, q);
4239 if (!q->nr_hw_queues)
4242 INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
4243 blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
4247 q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
4248 blk_mq_update_poll_flag(q);
4250 INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
4251 INIT_LIST_HEAD(&q->flush_list);
4252 INIT_LIST_HEAD(&q->requeue_list);
4253 spin_lock_init(&q->requeue_lock);
4255 q->nr_requests = set->queue_depth;
4257 blk_mq_init_cpu_queues(q, set->nr_hw_queues);
4258 blk_mq_add_queue_tag_set(set, q);
4259 blk_mq_map_swqueue(q);
4268 EXPORT_SYMBOL(blk_mq_init_allocated_queue);
4270 /* tags can _not_ be used after returning from blk_mq_exit_queue */
4271 void blk_mq_exit_queue(struct request_queue *q)
4273 struct blk_mq_tag_set *set = q->tag_set;
4275 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
4276 blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
4277 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
4278 blk_mq_del_queue_tag_set(q);
4281 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
4285 if (blk_mq_is_shared_tags(set->flags)) {
4286 set->shared_tags = blk_mq_alloc_map_and_rqs(set,
4289 if (!set->shared_tags)
4293 for (i = 0; i < set->nr_hw_queues; i++) {
4294 if (!__blk_mq_alloc_map_and_rqs(set, i))
4303 __blk_mq_free_map_and_rqs(set, i);
4305 if (blk_mq_is_shared_tags(set->flags)) {
4306 blk_mq_free_map_and_rqs(set, set->shared_tags,
4307 BLK_MQ_NO_HCTX_IDX);
4314 * Allocate the request maps associated with this tag_set. Note that this
4315 * may reduce the depth asked for, if memory is tight. set->queue_depth
4316 * will be updated to reflect the allocated depth.
4318 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
4323 depth = set->queue_depth;
4325 err = __blk_mq_alloc_rq_maps(set);
4329 set->queue_depth >>= 1;
4330 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
4334 } while (set->queue_depth);
4336 if (!set->queue_depth || err) {
4337 pr_err("blk-mq: failed to allocate request map\n");
4341 if (depth != set->queue_depth)
4342 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
4343 depth, set->queue_depth);
4348 static void blk_mq_update_queue_map(struct blk_mq_tag_set *set)
4351 * blk_mq_map_queues() and multiple .map_queues() implementations
4352 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
4353 * number of hardware queues.
4355 if (set->nr_maps == 1)
4356 set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
4358 if (set->ops->map_queues && !is_kdump_kernel()) {
4362 * transport .map_queues is usually done in the following
4365 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
4366 * mask = get_cpu_mask(queue)
4367 * for_each_cpu(cpu, mask)
4368 * set->map[x].mq_map[cpu] = queue;
4371 * When we need to remap, the table has to be cleared for
4372 * killing stale mapping since one CPU may not be mapped
4375 for (i = 0; i < set->nr_maps; i++)
4376 blk_mq_clear_mq_map(&set->map[i]);
4378 set->ops->map_queues(set);
4380 BUG_ON(set->nr_maps > 1);
4381 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
4385 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
4386 int new_nr_hw_queues)
4388 struct blk_mq_tags **new_tags;
4391 if (set->nr_hw_queues >= new_nr_hw_queues)
4394 new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
4395 GFP_KERNEL, set->numa_node);
4400 memcpy(new_tags, set->tags, set->nr_hw_queues *
4401 sizeof(*set->tags));
4403 set->tags = new_tags;
4405 for (i = set->nr_hw_queues; i < new_nr_hw_queues; i++) {
4406 if (!__blk_mq_alloc_map_and_rqs(set, i)) {
4407 while (--i >= set->nr_hw_queues)
4408 __blk_mq_free_map_and_rqs(set, i);
4415 set->nr_hw_queues = new_nr_hw_queues;
4420 * Alloc a tag set to be associated with one or more request queues.
4421 * May fail with EINVAL for various error conditions. May adjust the
4422 * requested depth down, if it's too large. In that case, the set
4423 * value will be stored in set->queue_depth.
4425 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
4429 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
4431 if (!set->nr_hw_queues)
4433 if (!set->queue_depth)
4435 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
4438 if (!set->ops->queue_rq)
4441 if (!set->ops->get_budget ^ !set->ops->put_budget)
4444 if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
4445 pr_info("blk-mq: reduced tag depth to %u\n",
4447 set->queue_depth = BLK_MQ_MAX_DEPTH;
4452 else if (set->nr_maps > HCTX_MAX_TYPES)
4456 * If a crashdump is active, then we are potentially in a very
4457 * memory constrained environment. Limit us to 1 queue and
4458 * 64 tags to prevent using too much memory.
4460 if (is_kdump_kernel()) {
4461 set->nr_hw_queues = 1;
4463 set->queue_depth = min(64U, set->queue_depth);
4466 * There is no use for more h/w queues than cpus if we just have
4469 if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
4470 set->nr_hw_queues = nr_cpu_ids;
4472 if (set->flags & BLK_MQ_F_BLOCKING) {
4473 set->srcu = kmalloc(sizeof(*set->srcu), GFP_KERNEL);
4476 ret = init_srcu_struct(set->srcu);
4482 set->tags = kcalloc_node(set->nr_hw_queues,
4483 sizeof(struct blk_mq_tags *), GFP_KERNEL,
4486 goto out_cleanup_srcu;
4488 for (i = 0; i < set->nr_maps; i++) {
4489 set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
4490 sizeof(set->map[i].mq_map[0]),
4491 GFP_KERNEL, set->numa_node);
4492 if (!set->map[i].mq_map)
4493 goto out_free_mq_map;
4494 set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues;
4497 blk_mq_update_queue_map(set);
4499 ret = blk_mq_alloc_set_map_and_rqs(set);
4501 goto out_free_mq_map;
4503 mutex_init(&set->tag_list_lock);
4504 INIT_LIST_HEAD(&set->tag_list);
4509 for (i = 0; i < set->nr_maps; i++) {
4510 kfree(set->map[i].mq_map);
4511 set->map[i].mq_map = NULL;
4516 if (set->flags & BLK_MQ_F_BLOCKING)
4517 cleanup_srcu_struct(set->srcu);
4519 if (set->flags & BLK_MQ_F_BLOCKING)
4523 EXPORT_SYMBOL(blk_mq_alloc_tag_set);
4525 /* allocate and initialize a tagset for a simple single-queue device */
4526 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set,
4527 const struct blk_mq_ops *ops, unsigned int queue_depth,
4528 unsigned int set_flags)
4530 memset(set, 0, sizeof(*set));
4532 set->nr_hw_queues = 1;
4534 set->queue_depth = queue_depth;
4535 set->numa_node = NUMA_NO_NODE;
4536 set->flags = set_flags;
4537 return blk_mq_alloc_tag_set(set);
4539 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set);
4541 void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
4545 for (i = 0; i < set->nr_hw_queues; i++)
4546 __blk_mq_free_map_and_rqs(set, i);
4548 if (blk_mq_is_shared_tags(set->flags)) {
4549 blk_mq_free_map_and_rqs(set, set->shared_tags,
4550 BLK_MQ_NO_HCTX_IDX);
4553 for (j = 0; j < set->nr_maps; j++) {
4554 kfree(set->map[j].mq_map);
4555 set->map[j].mq_map = NULL;
4560 if (set->flags & BLK_MQ_F_BLOCKING) {
4561 cleanup_srcu_struct(set->srcu);
4565 EXPORT_SYMBOL(blk_mq_free_tag_set);
4567 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
4569 struct blk_mq_tag_set *set = q->tag_set;
4570 struct blk_mq_hw_ctx *hctx;
4577 if (q->nr_requests == nr)
4580 blk_mq_freeze_queue(q);
4581 blk_mq_quiesce_queue(q);
4584 queue_for_each_hw_ctx(q, hctx, i) {
4588 * If we're using an MQ scheduler, just update the scheduler
4589 * queue depth. This is similar to what the old code would do.
4591 if (hctx->sched_tags) {
4592 ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
4595 ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
4600 if (q->elevator && q->elevator->type->ops.depth_updated)
4601 q->elevator->type->ops.depth_updated(hctx);
4604 q->nr_requests = nr;
4605 if (blk_mq_is_shared_tags(set->flags)) {
4607 blk_mq_tag_update_sched_shared_tags(q);
4609 blk_mq_tag_resize_shared_tags(set, nr);
4613 blk_mq_unquiesce_queue(q);
4614 blk_mq_unfreeze_queue(q);
4620 * request_queue and elevator_type pair.
4621 * It is just used by __blk_mq_update_nr_hw_queues to cache
4622 * the elevator_type associated with a request_queue.
4624 struct blk_mq_qe_pair {
4625 struct list_head node;
4626 struct request_queue *q;
4627 struct elevator_type *type;
4631 * Cache the elevator_type in qe pair list and switch the
4632 * io scheduler to 'none'
4634 static bool blk_mq_elv_switch_none(struct list_head *head,
4635 struct request_queue *q)
4637 struct blk_mq_qe_pair *qe;
4639 qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
4643 /* q->elevator needs protection from ->sysfs_lock */
4644 mutex_lock(&q->sysfs_lock);
4646 /* the check has to be done with holding sysfs_lock */
4652 INIT_LIST_HEAD(&qe->node);
4654 qe->type = q->elevator->type;
4655 /* keep a reference to the elevator module as we'll switch back */
4656 __elevator_get(qe->type);
4657 list_add(&qe->node, head);
4658 elevator_disable(q);
4660 mutex_unlock(&q->sysfs_lock);
4665 static struct blk_mq_qe_pair *blk_lookup_qe_pair(struct list_head *head,
4666 struct request_queue *q)
4668 struct blk_mq_qe_pair *qe;
4670 list_for_each_entry(qe, head, node)
4677 static void blk_mq_elv_switch_back(struct list_head *head,
4678 struct request_queue *q)
4680 struct blk_mq_qe_pair *qe;
4681 struct elevator_type *t;
4683 qe = blk_lookup_qe_pair(head, q);
4687 list_del(&qe->node);
4690 mutex_lock(&q->sysfs_lock);
4691 elevator_switch(q, t);
4692 /* drop the reference acquired in blk_mq_elv_switch_none */
4694 mutex_unlock(&q->sysfs_lock);
4697 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
4700 struct request_queue *q;
4702 int prev_nr_hw_queues = set->nr_hw_queues;
4705 lockdep_assert_held(&set->tag_list_lock);
4707 if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
4708 nr_hw_queues = nr_cpu_ids;
4709 if (nr_hw_queues < 1)
4711 if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
4714 list_for_each_entry(q, &set->tag_list, tag_set_list)
4715 blk_mq_freeze_queue(q);
4717 * Switch IO scheduler to 'none', cleaning up the data associated
4718 * with the previous scheduler. We will switch back once we are done
4719 * updating the new sw to hw queue mappings.
4721 list_for_each_entry(q, &set->tag_list, tag_set_list)
4722 if (!blk_mq_elv_switch_none(&head, q))
4725 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4726 blk_mq_debugfs_unregister_hctxs(q);
4727 blk_mq_sysfs_unregister_hctxs(q);
4730 if (blk_mq_realloc_tag_set_tags(set, nr_hw_queues) < 0)
4734 blk_mq_update_queue_map(set);
4735 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4736 blk_mq_realloc_hw_ctxs(set, q);
4737 blk_mq_update_poll_flag(q);
4738 if (q->nr_hw_queues != set->nr_hw_queues) {
4739 int i = prev_nr_hw_queues;
4741 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4742 nr_hw_queues, prev_nr_hw_queues);
4743 for (; i < set->nr_hw_queues; i++)
4744 __blk_mq_free_map_and_rqs(set, i);
4746 set->nr_hw_queues = prev_nr_hw_queues;
4749 blk_mq_map_swqueue(q);
4753 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4754 blk_mq_sysfs_register_hctxs(q);
4755 blk_mq_debugfs_register_hctxs(q);
4759 list_for_each_entry(q, &set->tag_list, tag_set_list)
4760 blk_mq_elv_switch_back(&head, q);
4762 list_for_each_entry(q, &set->tag_list, tag_set_list)
4763 blk_mq_unfreeze_queue(q);
4765 /* Free the excess tags when nr_hw_queues shrink. */
4766 for (i = set->nr_hw_queues; i < prev_nr_hw_queues; i++)
4767 __blk_mq_free_map_and_rqs(set, i);
4770 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
4772 mutex_lock(&set->tag_list_lock);
4773 __blk_mq_update_nr_hw_queues(set, nr_hw_queues);
4774 mutex_unlock(&set->tag_list_lock);
4776 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
4778 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
4779 struct io_comp_batch *iob, unsigned int flags)
4781 long state = get_current_state();
4785 ret = q->mq_ops->poll(hctx, iob);
4787 __set_current_state(TASK_RUNNING);
4791 if (signal_pending_state(state, current))
4792 __set_current_state(TASK_RUNNING);
4793 if (task_is_running(current))
4796 if (ret < 0 || (flags & BLK_POLL_ONESHOT))
4799 } while (!need_resched());
4801 __set_current_state(TASK_RUNNING);
4805 int blk_mq_poll(struct request_queue *q, blk_qc_t cookie,
4806 struct io_comp_batch *iob, unsigned int flags)
4808 struct blk_mq_hw_ctx *hctx = xa_load(&q->hctx_table, cookie);
4810 return blk_hctx_poll(q, hctx, iob, flags);
4813 int blk_rq_poll(struct request *rq, struct io_comp_batch *iob,
4814 unsigned int poll_flags)
4816 struct request_queue *q = rq->q;
4819 if (!blk_rq_is_poll(rq))
4821 if (!percpu_ref_tryget(&q->q_usage_counter))
4824 ret = blk_hctx_poll(q, rq->mq_hctx, iob, poll_flags);
4829 EXPORT_SYMBOL_GPL(blk_rq_poll);
4831 unsigned int blk_mq_rq_cpu(struct request *rq)
4833 return rq->mq_ctx->cpu;
4835 EXPORT_SYMBOL(blk_mq_rq_cpu);
4837 void blk_mq_cancel_work_sync(struct request_queue *q)
4839 struct blk_mq_hw_ctx *hctx;
4842 cancel_delayed_work_sync(&q->requeue_work);
4844 queue_for_each_hw_ctx(q, hctx, i)
4845 cancel_delayed_work_sync(&hctx->run_work);
4848 static int __init blk_mq_init(void)
4852 for_each_possible_cpu(i)
4853 init_llist_head(&per_cpu(blk_cpu_done, i));
4854 for_each_possible_cpu(i)
4855 INIT_CSD(&per_cpu(blk_cpu_csd, i),
4856 __blk_mq_complete_request_remote, NULL);
4857 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
4859 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
4860 "block/softirq:dead", NULL,
4861 blk_softirq_cpu_dead);
4862 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
4863 blk_mq_hctx_notify_dead);
4864 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
4865 blk_mq_hctx_notify_online,
4866 blk_mq_hctx_notify_offline);
4869 subsys_initcall(blk_mq_init);