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/topology.h>
25 #include <linux/sched/signal.h>
26 #include <linux/delay.h>
27 #include <linux/crash_dump.h>
28 #include <linux/prefetch.h>
29 #include <linux/blk-crypto.h>
30 #include <linux/part_stat.h>
31 #include <linux/sched/isolation.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"
44 static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
45 static DEFINE_PER_CPU(call_single_data_t, blk_cpu_csd);
47 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags);
48 static void blk_mq_request_bypass_insert(struct request *rq,
50 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
51 struct list_head *list);
52 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
53 struct io_comp_batch *iob, unsigned int flags);
56 * Check if any of the ctx, dispatch list or elevator
57 * have pending work in this hardware queue.
59 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
61 return !list_empty_careful(&hctx->dispatch) ||
62 sbitmap_any_bit_set(&hctx->ctx_map) ||
63 blk_mq_sched_has_work(hctx);
67 * Mark this ctx as having pending work in this hardware queue
69 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
70 struct blk_mq_ctx *ctx)
72 const int bit = ctx->index_hw[hctx->type];
74 if (!sbitmap_test_bit(&hctx->ctx_map, bit))
75 sbitmap_set_bit(&hctx->ctx_map, bit);
78 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
79 struct blk_mq_ctx *ctx)
81 const int bit = ctx->index_hw[hctx->type];
83 sbitmap_clear_bit(&hctx->ctx_map, bit);
87 struct block_device *part;
88 unsigned int inflight[2];
91 static bool blk_mq_check_inflight(struct request *rq, void *priv)
93 struct mq_inflight *mi = priv;
95 if (rq->part && blk_do_io_stat(rq) &&
96 (!bdev_is_partition(mi->part) || rq->part == mi->part) &&
97 blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
98 mi->inflight[rq_data_dir(rq)]++;
103 unsigned int blk_mq_in_flight(struct request_queue *q,
104 struct block_device *part)
106 struct mq_inflight mi = { .part = part };
108 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
110 return mi.inflight[0] + mi.inflight[1];
113 void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
114 unsigned int inflight[2])
116 struct mq_inflight mi = { .part = part };
118 blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
119 inflight[0] = mi.inflight[0];
120 inflight[1] = mi.inflight[1];
123 void blk_freeze_queue_start(struct request_queue *q)
125 mutex_lock(&q->mq_freeze_lock);
126 if (++q->mq_freeze_depth == 1) {
127 percpu_ref_kill(&q->q_usage_counter);
128 mutex_unlock(&q->mq_freeze_lock);
130 blk_mq_run_hw_queues(q, false);
132 mutex_unlock(&q->mq_freeze_lock);
135 EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
137 void blk_mq_freeze_queue_wait(struct request_queue *q)
139 wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
141 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
143 int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
144 unsigned long timeout)
146 return wait_event_timeout(q->mq_freeze_wq,
147 percpu_ref_is_zero(&q->q_usage_counter),
150 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
153 * Guarantee no request is in use, so we can change any data structure of
154 * the queue afterward.
156 void blk_freeze_queue(struct request_queue *q)
159 * In the !blk_mq case we are only calling this to kill the
160 * q_usage_counter, otherwise this increases the freeze depth
161 * and waits for it to return to zero. For this reason there is
162 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
163 * exported to drivers as the only user for unfreeze is blk_mq.
165 blk_freeze_queue_start(q);
166 blk_mq_freeze_queue_wait(q);
169 void blk_mq_freeze_queue(struct request_queue *q)
172 * ...just an alias to keep freeze and unfreeze actions balanced
173 * in the blk_mq_* namespace
177 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
179 void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
181 mutex_lock(&q->mq_freeze_lock);
183 q->q_usage_counter.data->force_atomic = true;
184 q->mq_freeze_depth--;
185 WARN_ON_ONCE(q->mq_freeze_depth < 0);
186 if (!q->mq_freeze_depth) {
187 percpu_ref_resurrect(&q->q_usage_counter);
188 wake_up_all(&q->mq_freeze_wq);
190 mutex_unlock(&q->mq_freeze_lock);
193 void blk_mq_unfreeze_queue(struct request_queue *q)
195 __blk_mq_unfreeze_queue(q, false);
197 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
200 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
201 * mpt3sas driver such that this function can be removed.
203 void blk_mq_quiesce_queue_nowait(struct request_queue *q)
207 spin_lock_irqsave(&q->queue_lock, flags);
208 if (!q->quiesce_depth++)
209 blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
210 spin_unlock_irqrestore(&q->queue_lock, flags);
212 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
215 * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
216 * @set: tag_set to wait on
218 * Note: it is driver's responsibility for making sure that quiesce has
219 * been started on or more of the request_queues of the tag_set. This
220 * function only waits for the quiesce on those request_queues that had
221 * the quiesce flag set using blk_mq_quiesce_queue_nowait.
223 void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set)
225 if (set->flags & BLK_MQ_F_BLOCKING)
226 synchronize_srcu(set->srcu);
230 EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
233 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
236 * Note: this function does not prevent that the struct request end_io()
237 * callback function is invoked. Once this function is returned, we make
238 * sure no dispatch can happen until the queue is unquiesced via
239 * blk_mq_unquiesce_queue().
241 void blk_mq_quiesce_queue(struct request_queue *q)
243 blk_mq_quiesce_queue_nowait(q);
244 /* nothing to wait for non-mq queues */
246 blk_mq_wait_quiesce_done(q->tag_set);
248 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
251 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
254 * This function recovers queue into the state before quiescing
255 * which is done by blk_mq_quiesce_queue.
257 void blk_mq_unquiesce_queue(struct request_queue *q)
260 bool run_queue = false;
262 spin_lock_irqsave(&q->queue_lock, flags);
263 if (WARN_ON_ONCE(q->quiesce_depth <= 0)) {
265 } else if (!--q->quiesce_depth) {
266 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
269 spin_unlock_irqrestore(&q->queue_lock, flags);
271 /* dispatch requests which are inserted during quiescing */
273 blk_mq_run_hw_queues(q, true);
275 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
277 void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set)
279 struct request_queue *q;
281 mutex_lock(&set->tag_list_lock);
282 list_for_each_entry(q, &set->tag_list, tag_set_list) {
283 if (!blk_queue_skip_tagset_quiesce(q))
284 blk_mq_quiesce_queue_nowait(q);
286 blk_mq_wait_quiesce_done(set);
287 mutex_unlock(&set->tag_list_lock);
289 EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);
291 void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set)
293 struct request_queue *q;
295 mutex_lock(&set->tag_list_lock);
296 list_for_each_entry(q, &set->tag_list, tag_set_list) {
297 if (!blk_queue_skip_tagset_quiesce(q))
298 blk_mq_unquiesce_queue(q);
300 mutex_unlock(&set->tag_list_lock);
302 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset);
304 void blk_mq_wake_waiters(struct request_queue *q)
306 struct blk_mq_hw_ctx *hctx;
309 queue_for_each_hw_ctx(q, hctx, i)
310 if (blk_mq_hw_queue_mapped(hctx))
311 blk_mq_tag_wakeup_all(hctx->tags, true);
314 void blk_rq_init(struct request_queue *q, struct request *rq)
316 memset(rq, 0, sizeof(*rq));
318 INIT_LIST_HEAD(&rq->queuelist);
320 rq->__sector = (sector_t) -1;
321 INIT_HLIST_NODE(&rq->hash);
322 RB_CLEAR_NODE(&rq->rb_node);
323 rq->tag = BLK_MQ_NO_TAG;
324 rq->internal_tag = BLK_MQ_NO_TAG;
325 rq->start_time_ns = blk_time_get_ns();
327 blk_crypto_rq_set_defaults(rq);
329 EXPORT_SYMBOL(blk_rq_init);
331 /* Set start and alloc time when the allocated request is actually used */
332 static inline void blk_mq_rq_time_init(struct request *rq, u64 alloc_time_ns)
334 if (blk_mq_need_time_stamp(rq))
335 rq->start_time_ns = blk_time_get_ns();
337 rq->start_time_ns = 0;
339 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
340 if (blk_queue_rq_alloc_time(rq->q))
341 rq->alloc_time_ns = alloc_time_ns ?: rq->start_time_ns;
343 rq->alloc_time_ns = 0;
347 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
348 struct blk_mq_tags *tags, unsigned int tag)
350 struct blk_mq_ctx *ctx = data->ctx;
351 struct blk_mq_hw_ctx *hctx = data->hctx;
352 struct request_queue *q = data->q;
353 struct request *rq = tags->static_rqs[tag];
358 rq->cmd_flags = data->cmd_flags;
360 if (data->flags & BLK_MQ_REQ_PM)
361 data->rq_flags |= RQF_PM;
362 if (blk_queue_io_stat(q))
363 data->rq_flags |= RQF_IO_STAT;
364 rq->rq_flags = data->rq_flags;
366 if (data->rq_flags & RQF_SCHED_TAGS) {
367 rq->tag = BLK_MQ_NO_TAG;
368 rq->internal_tag = tag;
371 rq->internal_tag = BLK_MQ_NO_TAG;
376 rq->io_start_time_ns = 0;
377 rq->stats_sectors = 0;
378 rq->nr_phys_segments = 0;
379 #if defined(CONFIG_BLK_DEV_INTEGRITY)
380 rq->nr_integrity_segments = 0;
383 rq->end_io_data = NULL;
385 blk_crypto_rq_set_defaults(rq);
386 INIT_LIST_HEAD(&rq->queuelist);
387 /* tag was already set */
388 WRITE_ONCE(rq->deadline, 0);
391 if (rq->rq_flags & RQF_USE_SCHED) {
392 struct elevator_queue *e = data->q->elevator;
394 INIT_HLIST_NODE(&rq->hash);
395 RB_CLEAR_NODE(&rq->rb_node);
397 if (e->type->ops.prepare_request)
398 e->type->ops.prepare_request(rq);
404 static inline struct request *
405 __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data)
407 unsigned int tag, tag_offset;
408 struct blk_mq_tags *tags;
410 unsigned long tag_mask;
413 tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset);
414 if (unlikely(!tag_mask))
417 tags = blk_mq_tags_from_data(data);
418 for (i = 0; tag_mask; i++) {
419 if (!(tag_mask & (1UL << i)))
421 tag = tag_offset + i;
422 prefetch(tags->static_rqs[tag]);
423 tag_mask &= ~(1UL << i);
424 rq = blk_mq_rq_ctx_init(data, tags, tag);
425 rq_list_add(data->cached_rq, rq);
428 if (!(data->rq_flags & RQF_SCHED_TAGS))
429 blk_mq_add_active_requests(data->hctx, nr);
430 /* caller already holds a reference, add for remainder */
431 percpu_ref_get_many(&data->q->q_usage_counter, nr - 1);
434 return rq_list_pop(data->cached_rq);
437 static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
439 struct request_queue *q = data->q;
440 u64 alloc_time_ns = 0;
444 /* alloc_time includes depth and tag waits */
445 if (blk_queue_rq_alloc_time(q))
446 alloc_time_ns = blk_time_get_ns();
448 if (data->cmd_flags & REQ_NOWAIT)
449 data->flags |= BLK_MQ_REQ_NOWAIT;
452 data->ctx = blk_mq_get_ctx(q);
453 data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx);
457 * All requests use scheduler tags when an I/O scheduler is
458 * enabled for the queue.
460 data->rq_flags |= RQF_SCHED_TAGS;
463 * Flush/passthrough requests are special and go directly to the
466 if ((data->cmd_flags & REQ_OP_MASK) != REQ_OP_FLUSH &&
467 !blk_op_is_passthrough(data->cmd_flags)) {
468 struct elevator_mq_ops *ops = &q->elevator->type->ops;
470 WARN_ON_ONCE(data->flags & BLK_MQ_REQ_RESERVED);
472 data->rq_flags |= RQF_USE_SCHED;
473 if (ops->limit_depth)
474 ops->limit_depth(data->cmd_flags, data);
477 blk_mq_tag_busy(data->hctx);
480 if (data->flags & BLK_MQ_REQ_RESERVED)
481 data->rq_flags |= RQF_RESV;
484 * Try batched alloc if we want more than 1 tag.
486 if (data->nr_tags > 1) {
487 rq = __blk_mq_alloc_requests_batch(data);
489 blk_mq_rq_time_init(rq, alloc_time_ns);
496 * Waiting allocations only fail because of an inactive hctx. In that
497 * case just retry the hctx assignment and tag allocation as CPU hotplug
498 * should have migrated us to an online CPU by now.
500 tag = blk_mq_get_tag(data);
501 if (tag == BLK_MQ_NO_TAG) {
502 if (data->flags & BLK_MQ_REQ_NOWAIT)
505 * Give up the CPU and sleep for a random short time to
506 * ensure that thread using a realtime scheduling class
507 * are migrated off the CPU, and thus off the hctx that
514 if (!(data->rq_flags & RQF_SCHED_TAGS))
515 blk_mq_inc_active_requests(data->hctx);
516 rq = blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag);
517 blk_mq_rq_time_init(rq, alloc_time_ns);
521 static struct request *blk_mq_rq_cache_fill(struct request_queue *q,
522 struct blk_plug *plug,
524 blk_mq_req_flags_t flags)
526 struct blk_mq_alloc_data data = {
530 .nr_tags = plug->nr_ios,
531 .cached_rq = &plug->cached_rq,
535 if (blk_queue_enter(q, flags))
540 rq = __blk_mq_alloc_requests(&data);
546 static struct request *blk_mq_alloc_cached_request(struct request_queue *q,
548 blk_mq_req_flags_t flags)
550 struct blk_plug *plug = current->plug;
556 if (rq_list_empty(plug->cached_rq)) {
557 if (plug->nr_ios == 1)
559 rq = blk_mq_rq_cache_fill(q, plug, opf, flags);
563 rq = rq_list_peek(&plug->cached_rq);
564 if (!rq || rq->q != q)
567 if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type)
569 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf))
572 plug->cached_rq = rq_list_next(rq);
573 blk_mq_rq_time_init(rq, 0);
577 INIT_LIST_HEAD(&rq->queuelist);
581 struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf,
582 blk_mq_req_flags_t flags)
586 rq = blk_mq_alloc_cached_request(q, opf, flags);
588 struct blk_mq_alloc_data data = {
596 ret = blk_queue_enter(q, flags);
600 rq = __blk_mq_alloc_requests(&data);
605 rq->__sector = (sector_t) -1;
606 rq->bio = rq->biotail = NULL;
610 return ERR_PTR(-EWOULDBLOCK);
612 EXPORT_SYMBOL(blk_mq_alloc_request);
614 struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
615 blk_opf_t opf, blk_mq_req_flags_t flags, unsigned int hctx_idx)
617 struct blk_mq_alloc_data data = {
623 u64 alloc_time_ns = 0;
629 /* alloc_time includes depth and tag waits */
630 if (blk_queue_rq_alloc_time(q))
631 alloc_time_ns = blk_time_get_ns();
634 * If the tag allocator sleeps we could get an allocation for a
635 * different hardware context. No need to complicate the low level
636 * allocator for this for the rare use case of a command tied to
639 if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)) ||
640 WARN_ON_ONCE(!(flags & BLK_MQ_REQ_RESERVED)))
641 return ERR_PTR(-EINVAL);
643 if (hctx_idx >= q->nr_hw_queues)
644 return ERR_PTR(-EIO);
646 ret = blk_queue_enter(q, flags);
651 * Check if the hardware context is actually mapped to anything.
652 * If not tell the caller that it should skip this queue.
655 data.hctx = xa_load(&q->hctx_table, hctx_idx);
656 if (!blk_mq_hw_queue_mapped(data.hctx))
658 cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
659 if (cpu >= nr_cpu_ids)
661 data.ctx = __blk_mq_get_ctx(q, cpu);
664 data.rq_flags |= RQF_SCHED_TAGS;
666 blk_mq_tag_busy(data.hctx);
668 if (flags & BLK_MQ_REQ_RESERVED)
669 data.rq_flags |= RQF_RESV;
672 tag = blk_mq_get_tag(&data);
673 if (tag == BLK_MQ_NO_TAG)
675 if (!(data.rq_flags & RQF_SCHED_TAGS))
676 blk_mq_inc_active_requests(data.hctx);
677 rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag);
678 blk_mq_rq_time_init(rq, alloc_time_ns);
680 rq->__sector = (sector_t) -1;
681 rq->bio = rq->biotail = NULL;
688 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
690 static void blk_mq_finish_request(struct request *rq)
692 struct request_queue *q = rq->q;
694 blk_zone_finish_request(rq);
696 if (rq->rq_flags & RQF_USE_SCHED) {
697 q->elevator->type->ops.finish_request(rq);
699 * For postflush request that may need to be
700 * completed twice, we should clear this flag
701 * to avoid double finish_request() on the rq.
703 rq->rq_flags &= ~RQF_USE_SCHED;
707 static void __blk_mq_free_request(struct request *rq)
709 struct request_queue *q = rq->q;
710 struct blk_mq_ctx *ctx = rq->mq_ctx;
711 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
712 const int sched_tag = rq->internal_tag;
714 blk_crypto_free_request(rq);
715 blk_pm_mark_last_busy(rq);
718 if (rq->tag != BLK_MQ_NO_TAG) {
719 blk_mq_dec_active_requests(hctx);
720 blk_mq_put_tag(hctx->tags, ctx, rq->tag);
722 if (sched_tag != BLK_MQ_NO_TAG)
723 blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
724 blk_mq_sched_restart(hctx);
728 void blk_mq_free_request(struct request *rq)
730 struct request_queue *q = rq->q;
732 blk_mq_finish_request(rq);
734 if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
735 laptop_io_completion(q->disk->bdi);
739 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
740 if (req_ref_put_and_test(rq))
741 __blk_mq_free_request(rq);
743 EXPORT_SYMBOL_GPL(blk_mq_free_request);
745 void blk_mq_free_plug_rqs(struct blk_plug *plug)
749 while ((rq = rq_list_pop(&plug->cached_rq)) != NULL)
750 blk_mq_free_request(rq);
753 void blk_dump_rq_flags(struct request *rq, char *msg)
755 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
756 rq->q->disk ? rq->q->disk->disk_name : "?",
757 (__force unsigned long long) rq->cmd_flags);
759 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
760 (unsigned long long)blk_rq_pos(rq),
761 blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
762 printk(KERN_INFO " bio %p, biotail %p, len %u\n",
763 rq->bio, rq->biotail, blk_rq_bytes(rq));
765 EXPORT_SYMBOL(blk_dump_rq_flags);
767 static void blk_account_io_completion(struct request *req, unsigned int bytes)
769 if (req->part && blk_do_io_stat(req)) {
770 const int sgrp = op_stat_group(req_op(req));
773 part_stat_add(req->part, sectors[sgrp], bytes >> 9);
778 static void blk_print_req_error(struct request *req, blk_status_t status)
780 printk_ratelimited(KERN_ERR
781 "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
782 "phys_seg %u prio class %u\n",
783 blk_status_to_str(status),
784 req->q->disk ? req->q->disk->disk_name : "?",
785 blk_rq_pos(req), (__force u32)req_op(req),
786 blk_op_str(req_op(req)),
787 (__force u32)(req->cmd_flags & ~REQ_OP_MASK),
788 req->nr_phys_segments,
789 IOPRIO_PRIO_CLASS(req->ioprio));
793 * Fully end IO on a request. Does not support partial completions, or
796 static void blk_complete_request(struct request *req)
798 const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0;
799 int total_bytes = blk_rq_bytes(req);
800 struct bio *bio = req->bio;
802 trace_block_rq_complete(req, BLK_STS_OK, total_bytes);
807 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ)
808 blk_integrity_complete(req, total_bytes);
811 * Upper layers may call blk_crypto_evict_key() anytime after the last
812 * bio_endio(). Therefore, the keyslot must be released before that.
814 blk_crypto_rq_put_keyslot(req);
816 blk_account_io_completion(req, total_bytes);
819 struct bio *next = bio->bi_next;
821 /* Completion has already been traced */
822 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
824 blk_zone_update_request_bio(req, bio);
832 * Reset counters so that the request stacking driver
833 * can find how many bytes remain in the request
843 * blk_update_request - Complete multiple bytes without completing the request
844 * @req: the request being processed
845 * @error: block status code
846 * @nr_bytes: number of bytes to complete for @req
849 * Ends I/O on a number of bytes attached to @req, but doesn't complete
850 * the request structure even if @req doesn't have leftover.
851 * If @req has leftover, sets it up for the next range of segments.
853 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
854 * %false return from this function.
857 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
858 * except in the consistency check at the end of this function.
861 * %false - this request doesn't have any more data
862 * %true - this request has more data
864 bool blk_update_request(struct request *req, blk_status_t error,
865 unsigned int nr_bytes)
867 bool is_flush = req->rq_flags & RQF_FLUSH_SEQ;
868 bool quiet = req->rq_flags & RQF_QUIET;
871 trace_block_rq_complete(req, error, nr_bytes);
876 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
878 blk_integrity_complete(req, nr_bytes);
881 * Upper layers may call blk_crypto_evict_key() anytime after the last
882 * bio_endio(). Therefore, the keyslot must be released before that.
884 if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req))
885 __blk_crypto_rq_put_keyslot(req);
887 if (unlikely(error && !blk_rq_is_passthrough(req) && !quiet) &&
888 !test_bit(GD_DEAD, &req->q->disk->state)) {
889 blk_print_req_error(req, error);
890 trace_block_rq_error(req, error, nr_bytes);
893 blk_account_io_completion(req, nr_bytes);
897 struct bio *bio = req->bio;
898 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
901 bio->bi_status = error;
903 if (bio_bytes == bio->bi_iter.bi_size) {
904 req->bio = bio->bi_next;
905 } else if (bio_is_zone_append(bio) && error == BLK_STS_OK) {
907 * Partial zone append completions cannot be supported
908 * as the BIO fragments may end up not being written
911 bio->bi_status = BLK_STS_IOERR;
914 /* Completion has already been traced */
915 bio_clear_flag(bio, BIO_TRACE_COMPLETION);
917 bio_set_flag(bio, BIO_QUIET);
919 bio_advance(bio, bio_bytes);
921 /* Don't actually finish bio if it's part of flush sequence */
922 if (!bio->bi_iter.bi_size) {
923 blk_zone_update_request_bio(req, bio);
928 total_bytes += bio_bytes;
929 nr_bytes -= bio_bytes;
940 * Reset counters so that the request stacking driver
941 * can find how many bytes remain in the request
948 req->__data_len -= total_bytes;
950 /* update sector only for requests with clear definition of sector */
951 if (!blk_rq_is_passthrough(req))
952 req->__sector += total_bytes >> 9;
954 /* mixed attributes always follow the first bio */
955 if (req->rq_flags & RQF_MIXED_MERGE) {
956 req->cmd_flags &= ~REQ_FAILFAST_MASK;
957 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
960 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
962 * If total number of sectors is less than the first segment
963 * size, something has gone terribly wrong.
965 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
966 blk_dump_rq_flags(req, "request botched");
967 req->__data_len = blk_rq_cur_bytes(req);
970 /* recalculate the number of segments */
971 req->nr_phys_segments = blk_recalc_rq_segments(req);
976 EXPORT_SYMBOL_GPL(blk_update_request);
978 static inline void blk_account_io_done(struct request *req, u64 now)
980 trace_block_io_done(req);
983 * Account IO completion. flush_rq isn't accounted as a
984 * normal IO on queueing nor completion. Accounting the
985 * containing request is enough.
987 if (blk_do_io_stat(req) && req->part &&
988 !(req->rq_flags & RQF_FLUSH_SEQ)) {
989 const int sgrp = op_stat_group(req_op(req));
992 update_io_ticks(req->part, jiffies, true);
993 part_stat_inc(req->part, ios[sgrp]);
994 part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
995 part_stat_local_dec(req->part,
996 in_flight[op_is_write(req_op(req))]);
1001 static inline void blk_account_io_start(struct request *req)
1003 trace_block_io_start(req);
1005 if (blk_do_io_stat(req)) {
1007 * All non-passthrough requests are created from a bio with one
1008 * exception: when a flush command that is part of a flush sequence
1009 * generated by the state machine in blk-flush.c is cloned onto the
1010 * lower device by dm-multipath we can get here without a bio.
1013 req->part = req->bio->bi_bdev;
1015 req->part = req->q->disk->part0;
1018 update_io_ticks(req->part, jiffies, false);
1019 part_stat_local_inc(req->part,
1020 in_flight[op_is_write(req_op(req))]);
1025 static inline void __blk_mq_end_request_acct(struct request *rq, u64 now)
1027 if (rq->rq_flags & RQF_STATS)
1028 blk_stat_add(rq, now);
1030 blk_mq_sched_completed_request(rq, now);
1031 blk_account_io_done(rq, now);
1034 inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
1036 if (blk_mq_need_time_stamp(rq))
1037 __blk_mq_end_request_acct(rq, blk_time_get_ns());
1039 blk_mq_finish_request(rq);
1042 rq_qos_done(rq->q, rq);
1043 if (rq->end_io(rq, error) == RQ_END_IO_FREE)
1044 blk_mq_free_request(rq);
1046 blk_mq_free_request(rq);
1049 EXPORT_SYMBOL(__blk_mq_end_request);
1051 void blk_mq_end_request(struct request *rq, blk_status_t error)
1053 if (blk_update_request(rq, error, blk_rq_bytes(rq)))
1055 __blk_mq_end_request(rq, error);
1057 EXPORT_SYMBOL(blk_mq_end_request);
1059 #define TAG_COMP_BATCH 32
1061 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
1062 int *tag_array, int nr_tags)
1064 struct request_queue *q = hctx->queue;
1066 blk_mq_sub_active_requests(hctx, nr_tags);
1068 blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
1069 percpu_ref_put_many(&q->q_usage_counter, nr_tags);
1072 void blk_mq_end_request_batch(struct io_comp_batch *iob)
1074 int tags[TAG_COMP_BATCH], nr_tags = 0;
1075 struct blk_mq_hw_ctx *cur_hctx = NULL;
1080 now = blk_time_get_ns();
1082 while ((rq = rq_list_pop(&iob->req_list)) != NULL) {
1084 prefetch(rq->rq_next);
1086 blk_complete_request(rq);
1088 __blk_mq_end_request_acct(rq, now);
1090 blk_mq_finish_request(rq);
1092 rq_qos_done(rq->q, rq);
1095 * If end_io handler returns NONE, then it still has
1096 * ownership of the request.
1098 if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
1101 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1102 if (!req_ref_put_and_test(rq))
1105 blk_crypto_free_request(rq);
1106 blk_pm_mark_last_busy(rq);
1108 if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) {
1110 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1112 cur_hctx = rq->mq_hctx;
1114 tags[nr_tags++] = rq->tag;
1118 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1120 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch);
1122 static void blk_complete_reqs(struct llist_head *list)
1124 struct llist_node *entry = llist_reverse_order(llist_del_all(list));
1125 struct request *rq, *next;
1127 llist_for_each_entry_safe(rq, next, entry, ipi_list)
1128 rq->q->mq_ops->complete(rq);
1131 static __latent_entropy void blk_done_softirq(void)
1133 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
1136 static int blk_softirq_cpu_dead(unsigned int cpu)
1138 blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
1142 static void __blk_mq_complete_request_remote(void *data)
1144 __raise_softirq_irqoff(BLOCK_SOFTIRQ);
1147 static inline bool blk_mq_complete_need_ipi(struct request *rq)
1149 int cpu = raw_smp_processor_id();
1151 if (!IS_ENABLED(CONFIG_SMP) ||
1152 !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
1155 * With force threaded interrupts enabled, raising softirq from an SMP
1156 * function call will always result in waking the ksoftirqd thread.
1157 * This is probably worse than completing the request on a different
1160 if (force_irqthreads())
1163 /* same CPU or cache domain and capacity? Complete locally */
1164 if (cpu == rq->mq_ctx->cpu ||
1165 (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
1166 cpus_share_cache(cpu, rq->mq_ctx->cpu) &&
1167 cpus_equal_capacity(cpu, rq->mq_ctx->cpu)))
1170 /* don't try to IPI to an offline CPU */
1171 return cpu_online(rq->mq_ctx->cpu);
1174 static void blk_mq_complete_send_ipi(struct request *rq)
1178 cpu = rq->mq_ctx->cpu;
1179 if (llist_add(&rq->ipi_list, &per_cpu(blk_cpu_done, cpu)))
1180 smp_call_function_single_async(cpu, &per_cpu(blk_cpu_csd, cpu));
1183 static void blk_mq_raise_softirq(struct request *rq)
1185 struct llist_head *list;
1188 list = this_cpu_ptr(&blk_cpu_done);
1189 if (llist_add(&rq->ipi_list, list))
1190 raise_softirq(BLOCK_SOFTIRQ);
1194 bool blk_mq_complete_request_remote(struct request *rq)
1196 WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
1199 * For request which hctx has only one ctx mapping,
1200 * or a polled request, always complete locally,
1201 * it's pointless to redirect the completion.
1203 if ((rq->mq_hctx->nr_ctx == 1 &&
1204 rq->mq_ctx->cpu == raw_smp_processor_id()) ||
1205 rq->cmd_flags & REQ_POLLED)
1208 if (blk_mq_complete_need_ipi(rq)) {
1209 blk_mq_complete_send_ipi(rq);
1213 if (rq->q->nr_hw_queues == 1) {
1214 blk_mq_raise_softirq(rq);
1219 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
1222 * blk_mq_complete_request - end I/O on a request
1223 * @rq: the request being processed
1226 * Complete a request by scheduling the ->complete_rq operation.
1228 void blk_mq_complete_request(struct request *rq)
1230 if (!blk_mq_complete_request_remote(rq))
1231 rq->q->mq_ops->complete(rq);
1233 EXPORT_SYMBOL(blk_mq_complete_request);
1236 * blk_mq_start_request - Start processing a request
1237 * @rq: Pointer to request to be started
1239 * Function used by device drivers to notify the block layer that a request
1240 * is going to be processed now, so blk layer can do proper initializations
1241 * such as starting the timeout timer.
1243 void blk_mq_start_request(struct request *rq)
1245 struct request_queue *q = rq->q;
1247 trace_block_rq_issue(rq);
1249 if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags) &&
1250 !blk_rq_is_passthrough(rq)) {
1251 rq->io_start_time_ns = blk_time_get_ns();
1252 rq->stats_sectors = blk_rq_sectors(rq);
1253 rq->rq_flags |= RQF_STATS;
1254 rq_qos_issue(q, rq);
1257 WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
1260 WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
1261 rq->mq_hctx->tags->rqs[rq->tag] = rq;
1263 if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
1264 blk_integrity_prepare(rq);
1266 if (rq->bio && rq->bio->bi_opf & REQ_POLLED)
1267 WRITE_ONCE(rq->bio->bi_cookie, rq->mq_hctx->queue_num);
1269 EXPORT_SYMBOL(blk_mq_start_request);
1272 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
1273 * queues. This is important for md arrays to benefit from merging
1276 static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
1278 if (plug->multiple_queues)
1279 return BLK_MAX_REQUEST_COUNT * 2;
1280 return BLK_MAX_REQUEST_COUNT;
1283 static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
1285 struct request *last = rq_list_peek(&plug->mq_list);
1287 if (!plug->rq_count) {
1288 trace_block_plug(rq->q);
1289 } else if (plug->rq_count >= blk_plug_max_rq_count(plug) ||
1290 (!blk_queue_nomerges(rq->q) &&
1291 blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
1292 blk_mq_flush_plug_list(plug, false);
1294 trace_block_plug(rq->q);
1297 if (!plug->multiple_queues && last && last->q != rq->q)
1298 plug->multiple_queues = true;
1300 * Any request allocated from sched tags can't be issued to
1301 * ->queue_rqs() directly
1303 if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS))
1304 plug->has_elevator = true;
1306 rq_list_add(&plug->mq_list, rq);
1311 * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
1312 * @rq: request to insert
1313 * @at_head: insert request at head or tail of queue
1316 * Insert a fully prepared request at the back of the I/O scheduler queue
1317 * for execution. Don't wait for completion.
1320 * This function will invoke @done directly if the queue is dead.
1322 void blk_execute_rq_nowait(struct request *rq, bool at_head)
1324 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1326 WARN_ON(irqs_disabled());
1327 WARN_ON(!blk_rq_is_passthrough(rq));
1329 blk_account_io_start(rq);
1331 if (current->plug && !at_head) {
1332 blk_add_rq_to_plug(current->plug, rq);
1336 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1337 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
1339 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
1341 struct blk_rq_wait {
1342 struct completion done;
1346 static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret)
1348 struct blk_rq_wait *wait = rq->end_io_data;
1351 complete(&wait->done);
1352 return RQ_END_IO_NONE;
1355 bool blk_rq_is_poll(struct request *rq)
1359 if (rq->mq_hctx->type != HCTX_TYPE_POLL)
1363 EXPORT_SYMBOL_GPL(blk_rq_is_poll);
1365 static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
1368 blk_hctx_poll(rq->q, rq->mq_hctx, NULL, 0);
1370 } while (!completion_done(wait));
1374 * blk_execute_rq - insert a request into queue for execution
1375 * @rq: request to insert
1376 * @at_head: insert request at head or tail of queue
1379 * Insert a fully prepared request at the back of the I/O scheduler queue
1380 * for execution and wait for completion.
1381 * Return: The blk_status_t result provided to blk_mq_end_request().
1383 blk_status_t blk_execute_rq(struct request *rq, bool at_head)
1385 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1386 struct blk_rq_wait wait = {
1387 .done = COMPLETION_INITIALIZER_ONSTACK(wait.done),
1390 WARN_ON(irqs_disabled());
1391 WARN_ON(!blk_rq_is_passthrough(rq));
1393 rq->end_io_data = &wait;
1394 rq->end_io = blk_end_sync_rq;
1396 blk_account_io_start(rq);
1397 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1398 blk_mq_run_hw_queue(hctx, false);
1400 if (blk_rq_is_poll(rq))
1401 blk_rq_poll_completion(rq, &wait.done);
1403 blk_wait_io(&wait.done);
1407 EXPORT_SYMBOL(blk_execute_rq);
1409 static void __blk_mq_requeue_request(struct request *rq)
1411 struct request_queue *q = rq->q;
1413 blk_mq_put_driver_tag(rq);
1415 trace_block_rq_requeue(rq);
1416 rq_qos_requeue(q, rq);
1418 if (blk_mq_request_started(rq)) {
1419 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1420 rq->rq_flags &= ~RQF_TIMED_OUT;
1424 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
1426 struct request_queue *q = rq->q;
1427 unsigned long flags;
1429 __blk_mq_requeue_request(rq);
1431 /* this request will be re-inserted to io scheduler queue */
1432 blk_mq_sched_requeue_request(rq);
1434 spin_lock_irqsave(&q->requeue_lock, flags);
1435 list_add_tail(&rq->queuelist, &q->requeue_list);
1436 spin_unlock_irqrestore(&q->requeue_lock, flags);
1438 if (kick_requeue_list)
1439 blk_mq_kick_requeue_list(q);
1441 EXPORT_SYMBOL(blk_mq_requeue_request);
1443 static void blk_mq_requeue_work(struct work_struct *work)
1445 struct request_queue *q =
1446 container_of(work, struct request_queue, requeue_work.work);
1448 LIST_HEAD(flush_list);
1451 spin_lock_irq(&q->requeue_lock);
1452 list_splice_init(&q->requeue_list, &rq_list);
1453 list_splice_init(&q->flush_list, &flush_list);
1454 spin_unlock_irq(&q->requeue_lock);
1456 while (!list_empty(&rq_list)) {
1457 rq = list_entry(rq_list.next, struct request, queuelist);
1459 * If RQF_DONTPREP ist set, the request has been started by the
1460 * driver already and might have driver-specific data allocated
1461 * already. Insert it into the hctx dispatch list to avoid
1462 * block layer merges for the request.
1464 if (rq->rq_flags & RQF_DONTPREP) {
1465 list_del_init(&rq->queuelist);
1466 blk_mq_request_bypass_insert(rq, 0);
1468 list_del_init(&rq->queuelist);
1469 blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
1473 while (!list_empty(&flush_list)) {
1474 rq = list_entry(flush_list.next, struct request, queuelist);
1475 list_del_init(&rq->queuelist);
1476 blk_mq_insert_request(rq, 0);
1479 blk_mq_run_hw_queues(q, false);
1482 void blk_mq_kick_requeue_list(struct request_queue *q)
1484 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
1486 EXPORT_SYMBOL(blk_mq_kick_requeue_list);
1488 void blk_mq_delay_kick_requeue_list(struct request_queue *q,
1489 unsigned long msecs)
1491 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
1492 msecs_to_jiffies(msecs));
1494 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
1496 static bool blk_is_flush_data_rq(struct request *rq)
1498 return (rq->rq_flags & RQF_FLUSH_SEQ) && !is_flush_rq(rq);
1501 static bool blk_mq_rq_inflight(struct request *rq, void *priv)
1504 * If we find a request that isn't idle we know the queue is busy
1505 * as it's checked in the iter.
1506 * Return false to stop the iteration.
1508 * In case of queue quiesce, if one flush data request is completed,
1509 * don't count it as inflight given the flush sequence is suspended,
1510 * and the original flush data request is invisible to driver, just
1511 * like other pending requests because of quiesce
1513 if (blk_mq_request_started(rq) && !(blk_queue_quiesced(rq->q) &&
1514 blk_is_flush_data_rq(rq) &&
1515 blk_mq_request_completed(rq))) {
1525 bool blk_mq_queue_inflight(struct request_queue *q)
1529 blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
1532 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
1534 static void blk_mq_rq_timed_out(struct request *req)
1536 req->rq_flags |= RQF_TIMED_OUT;
1537 if (req->q->mq_ops->timeout) {
1538 enum blk_eh_timer_return ret;
1540 ret = req->q->mq_ops->timeout(req);
1541 if (ret == BLK_EH_DONE)
1543 WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
1549 struct blk_expired_data {
1550 bool has_timedout_rq;
1552 unsigned long timeout_start;
1555 static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired)
1557 unsigned long deadline;
1559 if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
1561 if (rq->rq_flags & RQF_TIMED_OUT)
1564 deadline = READ_ONCE(rq->deadline);
1565 if (time_after_eq(expired->timeout_start, deadline))
1568 if (expired->next == 0)
1569 expired->next = deadline;
1570 else if (time_after(expired->next, deadline))
1571 expired->next = deadline;
1575 void blk_mq_put_rq_ref(struct request *rq)
1577 if (is_flush_rq(rq)) {
1578 if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
1579 blk_mq_free_request(rq);
1580 } else if (req_ref_put_and_test(rq)) {
1581 __blk_mq_free_request(rq);
1585 static bool blk_mq_check_expired(struct request *rq, void *priv)
1587 struct blk_expired_data *expired = priv;
1590 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1591 * be reallocated underneath the timeout handler's processing, then
1592 * the expire check is reliable. If the request is not expired, then
1593 * it was completed and reallocated as a new request after returning
1594 * from blk_mq_check_expired().
1596 if (blk_mq_req_expired(rq, expired)) {
1597 expired->has_timedout_rq = true;
1603 static bool blk_mq_handle_expired(struct request *rq, void *priv)
1605 struct blk_expired_data *expired = priv;
1607 if (blk_mq_req_expired(rq, expired))
1608 blk_mq_rq_timed_out(rq);
1612 static void blk_mq_timeout_work(struct work_struct *work)
1614 struct request_queue *q =
1615 container_of(work, struct request_queue, timeout_work);
1616 struct blk_expired_data expired = {
1617 .timeout_start = jiffies,
1619 struct blk_mq_hw_ctx *hctx;
1622 /* A deadlock might occur if a request is stuck requiring a
1623 * timeout at the same time a queue freeze is waiting
1624 * completion, since the timeout code would not be able to
1625 * acquire the queue reference here.
1627 * That's why we don't use blk_queue_enter here; instead, we use
1628 * percpu_ref_tryget directly, because we need to be able to
1629 * obtain a reference even in the short window between the queue
1630 * starting to freeze, by dropping the first reference in
1631 * blk_freeze_queue_start, and the moment the last request is
1632 * consumed, marked by the instant q_usage_counter reaches
1635 if (!percpu_ref_tryget(&q->q_usage_counter))
1638 /* check if there is any timed-out request */
1639 blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
1640 if (expired.has_timedout_rq) {
1642 * Before walking tags, we must ensure any submit started
1643 * before the current time has finished. Since the submit
1644 * uses srcu or rcu, wait for a synchronization point to
1645 * ensure all running submits have finished
1647 blk_mq_wait_quiesce_done(q->tag_set);
1650 blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired);
1653 if (expired.next != 0) {
1654 mod_timer(&q->timeout, expired.next);
1657 * Request timeouts are handled as a forward rolling timer. If
1658 * we end up here it means that no requests are pending and
1659 * also that no request has been pending for a while. Mark
1660 * each hctx as idle.
1662 queue_for_each_hw_ctx(q, hctx, i) {
1663 /* the hctx may be unmapped, so check it here */
1664 if (blk_mq_hw_queue_mapped(hctx))
1665 blk_mq_tag_idle(hctx);
1671 struct flush_busy_ctx_data {
1672 struct blk_mq_hw_ctx *hctx;
1673 struct list_head *list;
1676 static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
1678 struct flush_busy_ctx_data *flush_data = data;
1679 struct blk_mq_hw_ctx *hctx = flush_data->hctx;
1680 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1681 enum hctx_type type = hctx->type;
1683 spin_lock(&ctx->lock);
1684 list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
1685 sbitmap_clear_bit(sb, bitnr);
1686 spin_unlock(&ctx->lock);
1691 * Process software queues that have been marked busy, splicing them
1692 * to the for-dispatch
1694 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
1696 struct flush_busy_ctx_data data = {
1701 sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
1703 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
1705 struct dispatch_rq_data {
1706 struct blk_mq_hw_ctx *hctx;
1710 static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
1713 struct dispatch_rq_data *dispatch_data = data;
1714 struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
1715 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1716 enum hctx_type type = hctx->type;
1718 spin_lock(&ctx->lock);
1719 if (!list_empty(&ctx->rq_lists[type])) {
1720 dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
1721 list_del_init(&dispatch_data->rq->queuelist);
1722 if (list_empty(&ctx->rq_lists[type]))
1723 sbitmap_clear_bit(sb, bitnr);
1725 spin_unlock(&ctx->lock);
1727 return !dispatch_data->rq;
1730 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
1731 struct blk_mq_ctx *start)
1733 unsigned off = start ? start->index_hw[hctx->type] : 0;
1734 struct dispatch_rq_data data = {
1739 __sbitmap_for_each_set(&hctx->ctx_map, off,
1740 dispatch_rq_from_ctx, &data);
1745 bool __blk_mq_alloc_driver_tag(struct request *rq)
1747 struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
1748 unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
1751 blk_mq_tag_busy(rq->mq_hctx);
1753 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
1754 bt = &rq->mq_hctx->tags->breserved_tags;
1757 if (!hctx_may_queue(rq->mq_hctx, bt))
1761 tag = __sbitmap_queue_get(bt);
1762 if (tag == BLK_MQ_NO_TAG)
1765 rq->tag = tag + tag_offset;
1766 blk_mq_inc_active_requests(rq->mq_hctx);
1770 static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
1771 int flags, void *key)
1773 struct blk_mq_hw_ctx *hctx;
1775 hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
1777 spin_lock(&hctx->dispatch_wait_lock);
1778 if (!list_empty(&wait->entry)) {
1779 struct sbitmap_queue *sbq;
1781 list_del_init(&wait->entry);
1782 sbq = &hctx->tags->bitmap_tags;
1783 atomic_dec(&sbq->ws_active);
1785 spin_unlock(&hctx->dispatch_wait_lock);
1787 blk_mq_run_hw_queue(hctx, true);
1792 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1793 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1794 * restart. For both cases, take care to check the condition again after
1795 * marking us as waiting.
1797 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
1800 struct sbitmap_queue *sbq;
1801 struct wait_queue_head *wq;
1802 wait_queue_entry_t *wait;
1805 if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
1806 !(blk_mq_is_shared_tags(hctx->flags))) {
1807 blk_mq_sched_mark_restart_hctx(hctx);
1810 * It's possible that a tag was freed in the window between the
1811 * allocation failure and adding the hardware queue to the wait
1814 * Don't clear RESTART here, someone else could have set it.
1815 * At most this will cost an extra queue run.
1817 return blk_mq_get_driver_tag(rq);
1820 wait = &hctx->dispatch_wait;
1821 if (!list_empty_careful(&wait->entry))
1824 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag))
1825 sbq = &hctx->tags->breserved_tags;
1827 sbq = &hctx->tags->bitmap_tags;
1828 wq = &bt_wait_ptr(sbq, hctx)->wait;
1830 spin_lock_irq(&wq->lock);
1831 spin_lock(&hctx->dispatch_wait_lock);
1832 if (!list_empty(&wait->entry)) {
1833 spin_unlock(&hctx->dispatch_wait_lock);
1834 spin_unlock_irq(&wq->lock);
1838 atomic_inc(&sbq->ws_active);
1839 wait->flags &= ~WQ_FLAG_EXCLUSIVE;
1840 __add_wait_queue(wq, wait);
1843 * Add one explicit barrier since blk_mq_get_driver_tag() may
1844 * not imply barrier in case of failure.
1846 * Order adding us to wait queue and allocating driver tag.
1848 * The pair is the one implied in sbitmap_queue_wake_up() which
1849 * orders clearing sbitmap tag bits and waitqueue_active() in
1850 * __sbitmap_queue_wake_up(), since waitqueue_active() is lockless
1852 * Otherwise, re-order of adding wait queue and getting driver tag
1853 * may cause __sbitmap_queue_wake_up() to wake up nothing because
1854 * the waitqueue_active() may not observe us in wait queue.
1859 * It's possible that a tag was freed in the window between the
1860 * allocation failure and adding the hardware queue to the wait
1863 ret = blk_mq_get_driver_tag(rq);
1865 spin_unlock(&hctx->dispatch_wait_lock);
1866 spin_unlock_irq(&wq->lock);
1871 * We got a tag, remove ourselves from the wait queue to ensure
1872 * someone else gets the wakeup.
1874 list_del_init(&wait->entry);
1875 atomic_dec(&sbq->ws_active);
1876 spin_unlock(&hctx->dispatch_wait_lock);
1877 spin_unlock_irq(&wq->lock);
1882 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1883 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1885 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1886 * - EWMA is one simple way to compute running average value
1887 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1888 * - take 4 as factor for avoiding to get too small(0) result, and this
1889 * factor doesn't matter because EWMA decreases exponentially
1891 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
1895 ewma = hctx->dispatch_busy;
1900 ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
1902 ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
1903 ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
1905 hctx->dispatch_busy = ewma;
1908 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1910 static void blk_mq_handle_dev_resource(struct request *rq,
1911 struct list_head *list)
1913 list_add(&rq->queuelist, list);
1914 __blk_mq_requeue_request(rq);
1917 enum prep_dispatch {
1919 PREP_DISPATCH_NO_TAG,
1920 PREP_DISPATCH_NO_BUDGET,
1923 static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
1926 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1927 int budget_token = -1;
1930 budget_token = blk_mq_get_dispatch_budget(rq->q);
1931 if (budget_token < 0) {
1932 blk_mq_put_driver_tag(rq);
1933 return PREP_DISPATCH_NO_BUDGET;
1935 blk_mq_set_rq_budget_token(rq, budget_token);
1938 if (!blk_mq_get_driver_tag(rq)) {
1940 * The initial allocation attempt failed, so we need to
1941 * rerun the hardware queue when a tag is freed. The
1942 * waitqueue takes care of that. If the queue is run
1943 * before we add this entry back on the dispatch list,
1944 * we'll re-run it below.
1946 if (!blk_mq_mark_tag_wait(hctx, rq)) {
1948 * All budgets not got from this function will be put
1949 * together during handling partial dispatch
1952 blk_mq_put_dispatch_budget(rq->q, budget_token);
1953 return PREP_DISPATCH_NO_TAG;
1957 return PREP_DISPATCH_OK;
1960 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1961 static void blk_mq_release_budgets(struct request_queue *q,
1962 struct list_head *list)
1966 list_for_each_entry(rq, list, queuelist) {
1967 int budget_token = blk_mq_get_rq_budget_token(rq);
1969 if (budget_token >= 0)
1970 blk_mq_put_dispatch_budget(q, budget_token);
1975 * blk_mq_commit_rqs will notify driver using bd->last that there is no
1976 * more requests. (See comment in struct blk_mq_ops for commit_rqs for
1978 * Attention, we should explicitly call this in unusual cases:
1979 * 1) did not queue everything initially scheduled to queue
1980 * 2) the last attempt to queue a request failed
1982 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued,
1985 if (hctx->queue->mq_ops->commit_rqs && queued) {
1986 trace_block_unplug(hctx->queue, queued, !from_schedule);
1987 hctx->queue->mq_ops->commit_rqs(hctx);
1992 * Returns true if we did some work AND can potentially do more.
1994 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
1995 unsigned int nr_budgets)
1997 enum prep_dispatch prep;
1998 struct request_queue *q = hctx->queue;
2001 blk_status_t ret = BLK_STS_OK;
2002 bool needs_resource = false;
2004 if (list_empty(list))
2008 * Now process all the entries, sending them to the driver.
2012 struct blk_mq_queue_data bd;
2014 rq = list_first_entry(list, struct request, queuelist);
2016 WARN_ON_ONCE(hctx != rq->mq_hctx);
2017 prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
2018 if (prep != PREP_DISPATCH_OK)
2021 list_del_init(&rq->queuelist);
2024 bd.last = list_empty(list);
2027 * once the request is queued to lld, no need to cover the
2032 ret = q->mq_ops->queue_rq(hctx, &bd);
2037 case BLK_STS_RESOURCE:
2038 needs_resource = true;
2040 case BLK_STS_DEV_RESOURCE:
2041 blk_mq_handle_dev_resource(rq, list);
2044 blk_mq_end_request(rq, ret);
2046 } while (!list_empty(list));
2048 /* If we didn't flush the entire list, we could have told the driver
2049 * there was more coming, but that turned out to be a lie.
2051 if (!list_empty(list) || ret != BLK_STS_OK)
2052 blk_mq_commit_rqs(hctx, queued, false);
2055 * Any items that need requeuing? Stuff them into hctx->dispatch,
2056 * that is where we will continue on next queue run.
2058 if (!list_empty(list)) {
2060 /* For non-shared tags, the RESTART check will suffice */
2061 bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
2062 ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||
2063 blk_mq_is_shared_tags(hctx->flags));
2066 blk_mq_release_budgets(q, list);
2068 spin_lock(&hctx->lock);
2069 list_splice_tail_init(list, &hctx->dispatch);
2070 spin_unlock(&hctx->lock);
2073 * Order adding requests to hctx->dispatch and checking
2074 * SCHED_RESTART flag. The pair of this smp_mb() is the one
2075 * in blk_mq_sched_restart(). Avoid restart code path to
2076 * miss the new added requests to hctx->dispatch, meantime
2077 * SCHED_RESTART is observed here.
2082 * If SCHED_RESTART was set by the caller of this function and
2083 * it is no longer set that means that it was cleared by another
2084 * thread and hence that a queue rerun is needed.
2086 * If 'no_tag' is set, that means that we failed getting
2087 * a driver tag with an I/O scheduler attached. If our dispatch
2088 * waitqueue is no longer active, ensure that we run the queue
2089 * AFTER adding our entries back to the list.
2091 * If no I/O scheduler has been configured it is possible that
2092 * the hardware queue got stopped and restarted before requests
2093 * were pushed back onto the dispatch list. Rerun the queue to
2094 * avoid starvation. Notes:
2095 * - blk_mq_run_hw_queue() checks whether or not a queue has
2096 * been stopped before rerunning a queue.
2097 * - Some but not all block drivers stop a queue before
2098 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
2101 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
2102 * bit is set, run queue after a delay to avoid IO stalls
2103 * that could otherwise occur if the queue is idle. We'll do
2104 * similar if we couldn't get budget or couldn't lock a zone
2105 * and SCHED_RESTART is set.
2107 needs_restart = blk_mq_sched_needs_restart(hctx);
2108 if (prep == PREP_DISPATCH_NO_BUDGET)
2109 needs_resource = true;
2110 if (!needs_restart ||
2111 (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
2112 blk_mq_run_hw_queue(hctx, true);
2113 else if (needs_resource)
2114 blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
2116 blk_mq_update_dispatch_busy(hctx, true);
2120 blk_mq_update_dispatch_busy(hctx, false);
2124 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
2126 int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
2128 if (cpu >= nr_cpu_ids)
2129 cpu = cpumask_first(hctx->cpumask);
2134 * ->next_cpu is always calculated from hctx->cpumask, so simply use
2135 * it for speeding up the check
2137 static bool blk_mq_hctx_empty_cpumask(struct blk_mq_hw_ctx *hctx)
2139 return hctx->next_cpu >= nr_cpu_ids;
2143 * It'd be great if the workqueue API had a way to pass
2144 * in a mask and had some smarts for more clever placement.
2145 * For now we just round-robin here, switching for every
2146 * BLK_MQ_CPU_WORK_BATCH queued items.
2148 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
2151 int next_cpu = hctx->next_cpu;
2153 /* Switch to unbound if no allowable CPUs in this hctx */
2154 if (hctx->queue->nr_hw_queues == 1 || blk_mq_hctx_empty_cpumask(hctx))
2155 return WORK_CPU_UNBOUND;
2157 if (--hctx->next_cpu_batch <= 0) {
2159 next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
2161 if (next_cpu >= nr_cpu_ids)
2162 next_cpu = blk_mq_first_mapped_cpu(hctx);
2163 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
2167 * Do unbound schedule if we can't find a online CPU for this hctx,
2168 * and it should only happen in the path of handling CPU DEAD.
2170 if (!cpu_online(next_cpu)) {
2177 * Make sure to re-select CPU next time once after CPUs
2178 * in hctx->cpumask become online again.
2180 hctx->next_cpu = next_cpu;
2181 hctx->next_cpu_batch = 1;
2182 return WORK_CPU_UNBOUND;
2185 hctx->next_cpu = next_cpu;
2190 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
2191 * @hctx: Pointer to the hardware queue to run.
2192 * @msecs: Milliseconds of delay to wait before running the queue.
2194 * Run a hardware queue asynchronously with a delay of @msecs.
2196 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
2198 if (unlikely(blk_mq_hctx_stopped(hctx)))
2200 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
2201 msecs_to_jiffies(msecs));
2203 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
2206 * blk_mq_run_hw_queue - Start to run a hardware queue.
2207 * @hctx: Pointer to the hardware queue to run.
2208 * @async: If we want to run the queue asynchronously.
2210 * Check if the request queue is not in a quiesced state and if there are
2211 * pending requests to be sent. If this is true, run the queue to send requests
2214 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2219 * We can't run the queue inline with interrupts disabled.
2221 WARN_ON_ONCE(!async && in_interrupt());
2223 might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING);
2226 * When queue is quiesced, we may be switching io scheduler, or
2227 * updating nr_hw_queues, or other things, and we can't run queue
2228 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
2230 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
2233 __blk_mq_run_dispatch_ops(hctx->queue, false,
2234 need_run = !blk_queue_quiesced(hctx->queue) &&
2235 blk_mq_hctx_has_pending(hctx));
2240 if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) {
2241 blk_mq_delay_run_hw_queue(hctx, 0);
2245 blk_mq_run_dispatch_ops(hctx->queue,
2246 blk_mq_sched_dispatch_requests(hctx));
2248 EXPORT_SYMBOL(blk_mq_run_hw_queue);
2251 * Return prefered queue to dispatch from (if any) for non-mq aware IO
2254 static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
2256 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
2258 * If the IO scheduler does not respect hardware queues when
2259 * dispatching, we just don't bother with multiple HW queues and
2260 * dispatch from hctx for the current CPU since running multiple queues
2261 * just causes lock contention inside the scheduler and pointless cache
2264 struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT];
2266 if (!blk_mq_hctx_stopped(hctx))
2272 * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
2273 * @q: Pointer to the request queue to run.
2274 * @async: If we want to run the queue asynchronously.
2276 void blk_mq_run_hw_queues(struct request_queue *q, bool async)
2278 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2282 if (blk_queue_sq_sched(q))
2283 sq_hctx = blk_mq_get_sq_hctx(q);
2284 queue_for_each_hw_ctx(q, hctx, i) {
2285 if (blk_mq_hctx_stopped(hctx))
2288 * Dispatch from this hctx either if there's no hctx preferred
2289 * by IO scheduler or if it has requests that bypass the
2292 if (!sq_hctx || sq_hctx == hctx ||
2293 !list_empty_careful(&hctx->dispatch))
2294 blk_mq_run_hw_queue(hctx, async);
2297 EXPORT_SYMBOL(blk_mq_run_hw_queues);
2300 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
2301 * @q: Pointer to the request queue to run.
2302 * @msecs: Milliseconds of delay to wait before running the queues.
2304 void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
2306 struct blk_mq_hw_ctx *hctx, *sq_hctx;
2310 if (blk_queue_sq_sched(q))
2311 sq_hctx = blk_mq_get_sq_hctx(q);
2312 queue_for_each_hw_ctx(q, hctx, i) {
2313 if (blk_mq_hctx_stopped(hctx))
2316 * If there is already a run_work pending, leave the
2317 * pending delay untouched. Otherwise, a hctx can stall
2318 * if another hctx is re-delaying the other's work
2319 * before the work executes.
2321 if (delayed_work_pending(&hctx->run_work))
2324 * Dispatch from this hctx either if there's no hctx preferred
2325 * by IO scheduler or if it has requests that bypass the
2328 if (!sq_hctx || sq_hctx == hctx ||
2329 !list_empty_careful(&hctx->dispatch))
2330 blk_mq_delay_run_hw_queue(hctx, msecs);
2333 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
2336 * This function is often used for pausing .queue_rq() by driver when
2337 * there isn't enough resource or some conditions aren't satisfied, and
2338 * BLK_STS_RESOURCE is usually returned.
2340 * We do not guarantee that dispatch can be drained or blocked
2341 * after blk_mq_stop_hw_queue() returns. Please use
2342 * blk_mq_quiesce_queue() for that requirement.
2344 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
2346 cancel_delayed_work(&hctx->run_work);
2348 set_bit(BLK_MQ_S_STOPPED, &hctx->state);
2350 EXPORT_SYMBOL(blk_mq_stop_hw_queue);
2353 * This function is often used for pausing .queue_rq() by driver when
2354 * there isn't enough resource or some conditions aren't satisfied, and
2355 * BLK_STS_RESOURCE is usually returned.
2357 * We do not guarantee that dispatch can be drained or blocked
2358 * after blk_mq_stop_hw_queues() returns. Please use
2359 * blk_mq_quiesce_queue() for that requirement.
2361 void blk_mq_stop_hw_queues(struct request_queue *q)
2363 struct blk_mq_hw_ctx *hctx;
2366 queue_for_each_hw_ctx(q, hctx, i)
2367 blk_mq_stop_hw_queue(hctx);
2369 EXPORT_SYMBOL(blk_mq_stop_hw_queues);
2371 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
2373 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2375 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING);
2377 EXPORT_SYMBOL(blk_mq_start_hw_queue);
2379 void blk_mq_start_hw_queues(struct request_queue *q)
2381 struct blk_mq_hw_ctx *hctx;
2384 queue_for_each_hw_ctx(q, hctx, i)
2385 blk_mq_start_hw_queue(hctx);
2387 EXPORT_SYMBOL(blk_mq_start_hw_queues);
2389 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2391 if (!blk_mq_hctx_stopped(hctx))
2394 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2395 blk_mq_run_hw_queue(hctx, async);
2397 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
2399 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
2401 struct blk_mq_hw_ctx *hctx;
2404 queue_for_each_hw_ctx(q, hctx, i)
2405 blk_mq_start_stopped_hw_queue(hctx, async ||
2406 (hctx->flags & BLK_MQ_F_BLOCKING));
2408 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
2410 static void blk_mq_run_work_fn(struct work_struct *work)
2412 struct blk_mq_hw_ctx *hctx =
2413 container_of(work, struct blk_mq_hw_ctx, run_work.work);
2415 blk_mq_run_dispatch_ops(hctx->queue,
2416 blk_mq_sched_dispatch_requests(hctx));
2420 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2421 * @rq: Pointer to request to be inserted.
2422 * @flags: BLK_MQ_INSERT_*
2424 * Should only be used carefully, when the caller knows we want to
2425 * bypass a potential IO scheduler on the target device.
2427 static void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags)
2429 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2431 spin_lock(&hctx->lock);
2432 if (flags & BLK_MQ_INSERT_AT_HEAD)
2433 list_add(&rq->queuelist, &hctx->dispatch);
2435 list_add_tail(&rq->queuelist, &hctx->dispatch);
2436 spin_unlock(&hctx->lock);
2439 static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
2440 struct blk_mq_ctx *ctx, struct list_head *list,
2441 bool run_queue_async)
2444 enum hctx_type type = hctx->type;
2447 * Try to issue requests directly if the hw queue isn't busy to save an
2448 * extra enqueue & dequeue to the sw queue.
2450 if (!hctx->dispatch_busy && !run_queue_async) {
2451 blk_mq_run_dispatch_ops(hctx->queue,
2452 blk_mq_try_issue_list_directly(hctx, list));
2453 if (list_empty(list))
2458 * preemption doesn't flush plug list, so it's possible ctx->cpu is
2461 list_for_each_entry(rq, list, queuelist) {
2462 BUG_ON(rq->mq_ctx != ctx);
2463 trace_block_rq_insert(rq);
2464 if (rq->cmd_flags & REQ_NOWAIT)
2465 run_queue_async = true;
2468 spin_lock(&ctx->lock);
2469 list_splice_tail_init(list, &ctx->rq_lists[type]);
2470 blk_mq_hctx_mark_pending(hctx, ctx);
2471 spin_unlock(&ctx->lock);
2473 blk_mq_run_hw_queue(hctx, run_queue_async);
2476 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
2478 struct request_queue *q = rq->q;
2479 struct blk_mq_ctx *ctx = rq->mq_ctx;
2480 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2482 if (blk_rq_is_passthrough(rq)) {
2484 * Passthrough request have to be added to hctx->dispatch
2485 * directly. The device may be in a situation where it can't
2486 * handle FS request, and always returns BLK_STS_RESOURCE for
2487 * them, which gets them added to hctx->dispatch.
2489 * If a passthrough request is required to unblock the queues,
2490 * and it is added to the scheduler queue, there is no chance to
2491 * dispatch it given we prioritize requests in hctx->dispatch.
2493 blk_mq_request_bypass_insert(rq, flags);
2494 } else if (req_op(rq) == REQ_OP_FLUSH) {
2496 * Firstly normal IO request is inserted to scheduler queue or
2497 * sw queue, meantime we add flush request to dispatch queue(
2498 * hctx->dispatch) directly and there is at most one in-flight
2499 * flush request for each hw queue, so it doesn't matter to add
2500 * flush request to tail or front of the dispatch queue.
2502 * Secondly in case of NCQ, flush request belongs to non-NCQ
2503 * command, and queueing it will fail when there is any
2504 * in-flight normal IO request(NCQ command). When adding flush
2505 * rq to the front of hctx->dispatch, it is easier to introduce
2506 * extra time to flush rq's latency because of S_SCHED_RESTART
2507 * compared with adding to the tail of dispatch queue, then
2508 * chance of flush merge is increased, and less flush requests
2509 * will be issued to controller. It is observed that ~10% time
2510 * is saved in blktests block/004 on disk attached to AHCI/NCQ
2511 * drive when adding flush rq to the front of hctx->dispatch.
2513 * Simply queue flush rq to the front of hctx->dispatch so that
2514 * intensive flush workloads can benefit in case of NCQ HW.
2516 blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD);
2517 } else if (q->elevator) {
2520 WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG);
2522 list_add(&rq->queuelist, &list);
2523 q->elevator->type->ops.insert_requests(hctx, &list, flags);
2525 trace_block_rq_insert(rq);
2527 spin_lock(&ctx->lock);
2528 if (flags & BLK_MQ_INSERT_AT_HEAD)
2529 list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]);
2531 list_add_tail(&rq->queuelist,
2532 &ctx->rq_lists[hctx->type]);
2533 blk_mq_hctx_mark_pending(hctx, ctx);
2534 spin_unlock(&ctx->lock);
2538 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
2539 unsigned int nr_segs)
2543 if (bio->bi_opf & REQ_RAHEAD)
2544 rq->cmd_flags |= REQ_FAILFAST_MASK;
2546 rq->__sector = bio->bi_iter.bi_sector;
2547 rq->write_hint = bio->bi_write_hint;
2548 blk_rq_bio_prep(rq, bio, nr_segs);
2550 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2551 err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
2554 blk_account_io_start(rq);
2557 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
2558 struct request *rq, bool last)
2560 struct request_queue *q = rq->q;
2561 struct blk_mq_queue_data bd = {
2568 * For OK queue, we are done. For error, caller may kill it.
2569 * Any other error (busy), just add it to our list as we
2570 * previously would have done.
2572 ret = q->mq_ops->queue_rq(hctx, &bd);
2575 blk_mq_update_dispatch_busy(hctx, false);
2577 case BLK_STS_RESOURCE:
2578 case BLK_STS_DEV_RESOURCE:
2579 blk_mq_update_dispatch_busy(hctx, true);
2580 __blk_mq_requeue_request(rq);
2583 blk_mq_update_dispatch_busy(hctx, false);
2590 static bool blk_mq_get_budget_and_tag(struct request *rq)
2594 budget_token = blk_mq_get_dispatch_budget(rq->q);
2595 if (budget_token < 0)
2597 blk_mq_set_rq_budget_token(rq, budget_token);
2598 if (!blk_mq_get_driver_tag(rq)) {
2599 blk_mq_put_dispatch_budget(rq->q, budget_token);
2606 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2607 * @hctx: Pointer of the associated hardware queue.
2608 * @rq: Pointer to request to be sent.
2610 * If the device has enough resources to accept a new request now, send the
2611 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2612 * we can try send it another time in the future. Requests inserted at this
2613 * queue have higher priority.
2615 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
2620 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2621 blk_mq_insert_request(rq, 0);
2625 if ((rq->rq_flags & RQF_USE_SCHED) || !blk_mq_get_budget_and_tag(rq)) {
2626 blk_mq_insert_request(rq, 0);
2627 blk_mq_run_hw_queue(hctx, rq->cmd_flags & REQ_NOWAIT);
2631 ret = __blk_mq_issue_directly(hctx, rq, true);
2635 case BLK_STS_RESOURCE:
2636 case BLK_STS_DEV_RESOURCE:
2637 blk_mq_request_bypass_insert(rq, 0);
2638 blk_mq_run_hw_queue(hctx, false);
2641 blk_mq_end_request(rq, ret);
2646 static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
2648 struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2650 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2651 blk_mq_insert_request(rq, 0);
2655 if (!blk_mq_get_budget_and_tag(rq))
2656 return BLK_STS_RESOURCE;
2657 return __blk_mq_issue_directly(hctx, rq, last);
2660 static void blk_mq_plug_issue_direct(struct blk_plug *plug)
2662 struct blk_mq_hw_ctx *hctx = NULL;
2665 blk_status_t ret = BLK_STS_OK;
2667 while ((rq = rq_list_pop(&plug->mq_list))) {
2668 bool last = rq_list_empty(plug->mq_list);
2670 if (hctx != rq->mq_hctx) {
2672 blk_mq_commit_rqs(hctx, queued, false);
2678 ret = blk_mq_request_issue_directly(rq, last);
2683 case BLK_STS_RESOURCE:
2684 case BLK_STS_DEV_RESOURCE:
2685 blk_mq_request_bypass_insert(rq, 0);
2686 blk_mq_run_hw_queue(hctx, false);
2689 blk_mq_end_request(rq, ret);
2695 if (ret != BLK_STS_OK)
2696 blk_mq_commit_rqs(hctx, queued, false);
2699 static void __blk_mq_flush_plug_list(struct request_queue *q,
2700 struct blk_plug *plug)
2702 if (blk_queue_quiesced(q))
2704 q->mq_ops->queue_rqs(&plug->mq_list);
2707 static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
2709 struct blk_mq_hw_ctx *this_hctx = NULL;
2710 struct blk_mq_ctx *this_ctx = NULL;
2711 struct request *requeue_list = NULL;
2712 struct request **requeue_lastp = &requeue_list;
2713 unsigned int depth = 0;
2714 bool is_passthrough = false;
2718 struct request *rq = rq_list_pop(&plug->mq_list);
2721 this_hctx = rq->mq_hctx;
2722 this_ctx = rq->mq_ctx;
2723 is_passthrough = blk_rq_is_passthrough(rq);
2724 } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx ||
2725 is_passthrough != blk_rq_is_passthrough(rq)) {
2726 rq_list_add_tail(&requeue_lastp, rq);
2729 list_add(&rq->queuelist, &list);
2731 } while (!rq_list_empty(plug->mq_list));
2733 plug->mq_list = requeue_list;
2734 trace_block_unplug(this_hctx->queue, depth, !from_sched);
2736 percpu_ref_get(&this_hctx->queue->q_usage_counter);
2737 /* passthrough requests should never be issued to the I/O scheduler */
2738 if (is_passthrough) {
2739 spin_lock(&this_hctx->lock);
2740 list_splice_tail_init(&list, &this_hctx->dispatch);
2741 spin_unlock(&this_hctx->lock);
2742 blk_mq_run_hw_queue(this_hctx, from_sched);
2743 } else if (this_hctx->queue->elevator) {
2744 this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
2746 blk_mq_run_hw_queue(this_hctx, from_sched);
2748 blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched);
2750 percpu_ref_put(&this_hctx->queue->q_usage_counter);
2753 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
2759 * We may have been called recursively midway through handling
2760 * plug->mq_list via a schedule() in the driver's queue_rq() callback.
2761 * To avoid mq_list changing under our feet, clear rq_count early and
2762 * bail out specifically if rq_count is 0 rather than checking
2763 * whether the mq_list is empty.
2765 if (plug->rq_count == 0)
2767 depth = plug->rq_count;
2770 if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
2771 struct request_queue *q;
2773 rq = rq_list_peek(&plug->mq_list);
2775 trace_block_unplug(q, depth, true);
2778 * Peek first request and see if we have a ->queue_rqs() hook.
2779 * If we do, we can dispatch the whole plug list in one go. We
2780 * already know at this point that all requests belong to the
2781 * same queue, caller must ensure that's the case.
2783 if (q->mq_ops->queue_rqs) {
2784 blk_mq_run_dispatch_ops(q,
2785 __blk_mq_flush_plug_list(q, plug));
2786 if (rq_list_empty(plug->mq_list))
2790 blk_mq_run_dispatch_ops(q,
2791 blk_mq_plug_issue_direct(plug));
2792 if (rq_list_empty(plug->mq_list))
2797 blk_mq_dispatch_plug_list(plug, from_schedule);
2798 } while (!rq_list_empty(plug->mq_list));
2801 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
2802 struct list_head *list)
2805 blk_status_t ret = BLK_STS_OK;
2807 while (!list_empty(list)) {
2808 struct request *rq = list_first_entry(list, struct request,
2811 list_del_init(&rq->queuelist);
2812 ret = blk_mq_request_issue_directly(rq, list_empty(list));
2817 case BLK_STS_RESOURCE:
2818 case BLK_STS_DEV_RESOURCE:
2819 blk_mq_request_bypass_insert(rq, 0);
2820 if (list_empty(list))
2821 blk_mq_run_hw_queue(hctx, false);
2824 blk_mq_end_request(rq, ret);
2830 if (ret != BLK_STS_OK)
2831 blk_mq_commit_rqs(hctx, queued, false);
2834 static bool blk_mq_attempt_bio_merge(struct request_queue *q,
2835 struct bio *bio, unsigned int nr_segs)
2837 if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
2838 if (blk_attempt_plug_merge(q, bio, nr_segs))
2840 if (blk_mq_sched_bio_merge(q, bio, nr_segs))
2846 static struct request *blk_mq_get_new_requests(struct request_queue *q,
2847 struct blk_plug *plug,
2851 struct blk_mq_alloc_data data = {
2854 .cmd_flags = bio->bi_opf,
2858 rq_qos_throttle(q, bio);
2861 data.nr_tags = plug->nr_ios;
2863 data.cached_rq = &plug->cached_rq;
2866 rq = __blk_mq_alloc_requests(&data);
2869 rq_qos_cleanup(q, bio);
2870 if (bio->bi_opf & REQ_NOWAIT)
2871 bio_wouldblock_error(bio);
2876 * Check if there is a suitable cached request and return it.
2878 static struct request *blk_mq_peek_cached_request(struct blk_plug *plug,
2879 struct request_queue *q, blk_opf_t opf)
2881 enum hctx_type type = blk_mq_get_hctx_type(opf);
2886 rq = rq_list_peek(&plug->cached_rq);
2887 if (!rq || rq->q != q)
2889 if (type != rq->mq_hctx->type &&
2890 (type != HCTX_TYPE_READ || rq->mq_hctx->type != HCTX_TYPE_DEFAULT))
2892 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf))
2897 static void blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug,
2900 WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq);
2903 * If any qos ->throttle() end up blocking, we will have flushed the
2904 * plug and hence killed the cached_rq list as well. Pop this entry
2905 * before we throttle.
2907 plug->cached_rq = rq_list_next(rq);
2908 rq_qos_throttle(rq->q, bio);
2910 blk_mq_rq_time_init(rq, 0);
2911 rq->cmd_flags = bio->bi_opf;
2912 INIT_LIST_HEAD(&rq->queuelist);
2915 static bool bio_unaligned(const struct bio *bio, struct request_queue *q)
2917 unsigned int bs_mask = queue_logical_block_size(q) - 1;
2919 /* .bi_sector of any zero sized bio need to be initialized */
2920 if ((bio->bi_iter.bi_size & bs_mask) ||
2921 ((bio->bi_iter.bi_sector << SECTOR_SHIFT) & bs_mask))
2927 * blk_mq_submit_bio - Create and send a request to block device.
2928 * @bio: Bio pointer.
2930 * Builds up a request structure from @q and @bio and send to the device. The
2931 * request may not be queued directly to hardware if:
2932 * * This request can be merged with another one
2933 * * We want to place request at plug queue for possible future merging
2934 * * There is an IO scheduler active at this queue
2936 * It will not queue the request if there is an error with the bio, or at the
2939 void blk_mq_submit_bio(struct bio *bio)
2941 struct request_queue *q = bdev_get_queue(bio->bi_bdev);
2942 struct blk_plug *plug = current->plug;
2943 const int is_sync = op_is_sync(bio->bi_opf);
2944 struct blk_mq_hw_ctx *hctx;
2945 unsigned int nr_segs;
2950 * If the plug has a cached request for this queue, try to use it.
2952 rq = blk_mq_peek_cached_request(plug, q, bio->bi_opf);
2955 * A BIO that was released from a zone write plug has already been
2956 * through the preparation in this function, already holds a reference
2957 * on the queue usage counter, and is the only write BIO in-flight for
2958 * the target zone. Go straight to preparing a request for it.
2960 if (bio_zone_write_plugging(bio)) {
2961 nr_segs = bio->__bi_nr_segments;
2967 bio = blk_queue_bounce(bio, q);
2970 * The cached request already holds a q_usage_counter reference and we
2971 * don't have to acquire a new one if we use it.
2974 if (unlikely(bio_queue_enter(bio)))
2979 * Device reconfiguration may change logical block size, so alignment
2980 * check has to be done with queue usage counter held
2982 if (unlikely(bio_unaligned(bio, q))) {
2987 bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
2991 if (!bio_integrity_prep(bio))
2994 if (blk_mq_attempt_bio_merge(q, bio, nr_segs))
2997 if (blk_queue_is_zoned(q) && blk_zone_plug_bio(bio, nr_segs))
3002 rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
3006 blk_mq_use_cached_rq(rq, plug, bio);
3009 trace_block_getrq(bio);
3011 rq_qos_track(q, rq, bio);
3013 blk_mq_bio_to_request(rq, bio, nr_segs);
3015 ret = blk_crypto_rq_get_keyslot(rq);
3016 if (ret != BLK_STS_OK) {
3017 bio->bi_status = ret;
3019 blk_mq_free_request(rq);
3023 if (bio_zone_write_plugging(bio))
3024 blk_zone_write_plug_init_request(rq);
3026 if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq))
3030 blk_add_rq_to_plug(plug, rq);
3035 if ((rq->rq_flags & RQF_USE_SCHED) ||
3036 (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) {
3037 blk_mq_insert_request(rq, 0);
3038 blk_mq_run_hw_queue(hctx, true);
3040 blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq));
3046 * Don't drop the queue reference if we were trying to use a cached
3047 * request and thus didn't acquire one.
3053 #ifdef CONFIG_BLK_MQ_STACKING
3055 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
3056 * @rq: the request being queued
3058 blk_status_t blk_insert_cloned_request(struct request *rq)
3060 struct request_queue *q = rq->q;
3061 unsigned int max_sectors = blk_queue_get_max_sectors(rq);
3062 unsigned int max_segments = blk_rq_get_max_segments(rq);
3065 if (blk_rq_sectors(rq) > max_sectors) {
3067 * SCSI device does not have a good way to return if
3068 * Write Same/Zero is actually supported. If a device rejects
3069 * a non-read/write command (discard, write same,etc.) the
3070 * low-level device driver will set the relevant queue limit to
3071 * 0 to prevent blk-lib from issuing more of the offending
3072 * operations. Commands queued prior to the queue limit being
3073 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
3074 * errors being propagated to upper layers.
3076 if (max_sectors == 0)
3077 return BLK_STS_NOTSUPP;
3079 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
3080 __func__, blk_rq_sectors(rq), max_sectors);
3081 return BLK_STS_IOERR;
3085 * The queue settings related to segment counting may differ from the
3088 rq->nr_phys_segments = blk_recalc_rq_segments(rq);
3089 if (rq->nr_phys_segments > max_segments) {
3090 printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n",
3091 __func__, rq->nr_phys_segments, max_segments);
3092 return BLK_STS_IOERR;
3095 if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq)))
3096 return BLK_STS_IOERR;
3098 ret = blk_crypto_rq_get_keyslot(rq);
3099 if (ret != BLK_STS_OK)
3102 blk_account_io_start(rq);
3105 * Since we have a scheduler attached on the top device,
3106 * bypass a potential scheduler on the bottom device for
3109 blk_mq_run_dispatch_ops(q,
3110 ret = blk_mq_request_issue_directly(rq, true));
3112 blk_account_io_done(rq, blk_time_get_ns());
3115 EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
3118 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3119 * @rq: the clone request to be cleaned up
3122 * Free all bios in @rq for a cloned request.
3124 void blk_rq_unprep_clone(struct request *rq)
3128 while ((bio = rq->bio) != NULL) {
3129 rq->bio = bio->bi_next;
3134 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
3137 * blk_rq_prep_clone - Helper function to setup clone request
3138 * @rq: the request to be setup
3139 * @rq_src: original request to be cloned
3140 * @bs: bio_set that bios for clone are allocated from
3141 * @gfp_mask: memory allocation mask for bio
3142 * @bio_ctr: setup function to be called for each clone bio.
3143 * Returns %0 for success, non %0 for failure.
3144 * @data: private data to be passed to @bio_ctr
3147 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3148 * Also, pages which the original bios are pointing to are not copied
3149 * and the cloned bios just point same pages.
3150 * So cloned bios must be completed before original bios, which means
3151 * the caller must complete @rq before @rq_src.
3153 int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
3154 struct bio_set *bs, gfp_t gfp_mask,
3155 int (*bio_ctr)(struct bio *, struct bio *, void *),
3158 struct bio *bio, *bio_src;
3163 __rq_for_each_bio(bio_src, rq_src) {
3164 bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask,
3169 if (bio_ctr && bio_ctr(bio, bio_src, data))
3173 rq->biotail->bi_next = bio;
3176 rq->bio = rq->biotail = bio;
3181 /* Copy attributes of the original request to the clone request. */
3182 rq->__sector = blk_rq_pos(rq_src);
3183 rq->__data_len = blk_rq_bytes(rq_src);
3184 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
3185 rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
3186 rq->special_vec = rq_src->special_vec;
3188 rq->nr_phys_segments = rq_src->nr_phys_segments;
3189 rq->ioprio = rq_src->ioprio;
3190 rq->write_hint = rq_src->write_hint;
3192 if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
3200 blk_rq_unprep_clone(rq);
3204 EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3205 #endif /* CONFIG_BLK_MQ_STACKING */
3208 * Steal bios from a request and add them to a bio list.
3209 * The request must not have been partially completed before.
3211 void blk_steal_bios(struct bio_list *list, struct request *rq)
3215 list->tail->bi_next = rq->bio;
3217 list->head = rq->bio;
3218 list->tail = rq->biotail;
3226 EXPORT_SYMBOL_GPL(blk_steal_bios);
3228 static size_t order_to_size(unsigned int order)
3230 return (size_t)PAGE_SIZE << order;
3233 /* called before freeing request pool in @tags */
3234 static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
3235 struct blk_mq_tags *tags)
3238 unsigned long flags;
3241 * There is no need to clear mapping if driver tags is not initialized
3242 * or the mapping belongs to the driver tags.
3244 if (!drv_tags || drv_tags == tags)
3247 list_for_each_entry(page, &tags->page_list, lru) {
3248 unsigned long start = (unsigned long)page_address(page);
3249 unsigned long end = start + order_to_size(page->private);
3252 for (i = 0; i < drv_tags->nr_tags; i++) {
3253 struct request *rq = drv_tags->rqs[i];
3254 unsigned long rq_addr = (unsigned long)rq;
3256 if (rq_addr >= start && rq_addr < end) {
3257 WARN_ON_ONCE(req_ref_read(rq) != 0);
3258 cmpxchg(&drv_tags->rqs[i], rq, NULL);
3264 * Wait until all pending iteration is done.
3266 * Request reference is cleared and it is guaranteed to be observed
3267 * after the ->lock is released.
3269 spin_lock_irqsave(&drv_tags->lock, flags);
3270 spin_unlock_irqrestore(&drv_tags->lock, flags);
3273 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
3274 unsigned int hctx_idx)
3276 struct blk_mq_tags *drv_tags;
3279 if (list_empty(&tags->page_list))
3282 if (blk_mq_is_shared_tags(set->flags))
3283 drv_tags = set->shared_tags;
3285 drv_tags = set->tags[hctx_idx];
3287 if (tags->static_rqs && set->ops->exit_request) {
3290 for (i = 0; i < tags->nr_tags; i++) {
3291 struct request *rq = tags->static_rqs[i];
3295 set->ops->exit_request(set, rq, hctx_idx);
3296 tags->static_rqs[i] = NULL;
3300 blk_mq_clear_rq_mapping(drv_tags, tags);
3302 while (!list_empty(&tags->page_list)) {
3303 page = list_first_entry(&tags->page_list, struct page, lru);
3304 list_del_init(&page->lru);
3306 * Remove kmemleak object previously allocated in
3307 * blk_mq_alloc_rqs().
3309 kmemleak_free(page_address(page));
3310 __free_pages(page, page->private);
3314 void blk_mq_free_rq_map(struct blk_mq_tags *tags)
3318 kfree(tags->static_rqs);
3319 tags->static_rqs = NULL;
3321 blk_mq_free_tags(tags);
3324 static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set,
3325 unsigned int hctx_idx)
3329 for (i = 0; i < set->nr_maps; i++) {
3330 unsigned int start = set->map[i].queue_offset;
3331 unsigned int end = start + set->map[i].nr_queues;
3333 if (hctx_idx >= start && hctx_idx < end)
3337 if (i >= set->nr_maps)
3338 i = HCTX_TYPE_DEFAULT;
3343 static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set,
3344 unsigned int hctx_idx)
3346 enum hctx_type type = hctx_idx_to_type(set, hctx_idx);
3348 return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx);
3351 static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
3352 unsigned int hctx_idx,
3353 unsigned int nr_tags,
3354 unsigned int reserved_tags)
3356 int node = blk_mq_get_hctx_node(set, hctx_idx);
3357 struct blk_mq_tags *tags;
3359 if (node == NUMA_NO_NODE)
3360 node = set->numa_node;
3362 tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
3363 BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
3367 tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3368 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3373 tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3374 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3376 if (!tags->static_rqs)
3384 blk_mq_free_tags(tags);
3388 static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
3389 unsigned int hctx_idx, int node)
3393 if (set->ops->init_request) {
3394 ret = set->ops->init_request(set, rq, hctx_idx, node);
3399 WRITE_ONCE(rq->state, MQ_RQ_IDLE);
3403 static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
3404 struct blk_mq_tags *tags,
3405 unsigned int hctx_idx, unsigned int depth)
3407 unsigned int i, j, entries_per_page, max_order = 4;
3408 int node = blk_mq_get_hctx_node(set, hctx_idx);
3409 size_t rq_size, left;
3411 if (node == NUMA_NO_NODE)
3412 node = set->numa_node;
3414 INIT_LIST_HEAD(&tags->page_list);
3417 * rq_size is the size of the request plus driver payload, rounded
3418 * to the cacheline size
3420 rq_size = round_up(sizeof(struct request) + set->cmd_size,
3422 left = rq_size * depth;
3424 for (i = 0; i < depth; ) {
3425 int this_order = max_order;
3430 while (this_order && left < order_to_size(this_order - 1))
3434 page = alloc_pages_node(node,
3435 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
3441 if (order_to_size(this_order) < rq_size)
3448 page->private = this_order;
3449 list_add_tail(&page->lru, &tags->page_list);
3451 p = page_address(page);
3453 * Allow kmemleak to scan these pages as they contain pointers
3454 * to additional allocations like via ops->init_request().
3456 kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
3457 entries_per_page = order_to_size(this_order) / rq_size;
3458 to_do = min(entries_per_page, depth - i);
3459 left -= to_do * rq_size;
3460 for (j = 0; j < to_do; j++) {
3461 struct request *rq = p;
3463 tags->static_rqs[i] = rq;
3464 if (blk_mq_init_request(set, rq, hctx_idx, node)) {
3465 tags->static_rqs[i] = NULL;
3476 blk_mq_free_rqs(set, tags, hctx_idx);
3480 struct rq_iter_data {
3481 struct blk_mq_hw_ctx *hctx;
3485 static bool blk_mq_has_request(struct request *rq, void *data)
3487 struct rq_iter_data *iter_data = data;
3489 if (rq->mq_hctx != iter_data->hctx)
3491 iter_data->has_rq = true;
3495 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
3497 struct blk_mq_tags *tags = hctx->sched_tags ?
3498 hctx->sched_tags : hctx->tags;
3499 struct rq_iter_data data = {
3503 blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
3507 static bool blk_mq_hctx_has_online_cpu(struct blk_mq_hw_ctx *hctx,
3508 unsigned int this_cpu)
3510 enum hctx_type type = hctx->type;
3514 * hctx->cpumask has to rule out isolated CPUs, but userspace still
3515 * might submit IOs on these isolated CPUs, so use the queue map to
3516 * check if all CPUs mapped to this hctx are offline
3518 for_each_online_cpu(cpu) {
3519 struct blk_mq_hw_ctx *h = blk_mq_map_queue_type(hctx->queue,
3525 /* this hctx has at least one online CPU */
3526 if (this_cpu != cpu)
3533 static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
3535 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3536 struct blk_mq_hw_ctx, cpuhp_online);
3538 if (blk_mq_hctx_has_online_cpu(hctx, cpu))
3542 * Prevent new request from being allocated on the current hctx.
3544 * The smp_mb__after_atomic() Pairs with the implied barrier in
3545 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
3546 * seen once we return from the tag allocator.
3548 set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3549 smp_mb__after_atomic();
3552 * Try to grab a reference to the queue and wait for any outstanding
3553 * requests. If we could not grab a reference the queue has been
3554 * frozen and there are no requests.
3556 if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
3557 while (blk_mq_hctx_has_requests(hctx))
3559 percpu_ref_put(&hctx->queue->q_usage_counter);
3566 * Check if one CPU is mapped to the specified hctx
3568 * Isolated CPUs have been ruled out from hctx->cpumask, which is supposed
3569 * to be used for scheduling kworker only. For other usage, please call this
3570 * helper for checking if one CPU belongs to the specified hctx
3572 static bool blk_mq_cpu_mapped_to_hctx(unsigned int cpu,
3573 const struct blk_mq_hw_ctx *hctx)
3575 struct blk_mq_hw_ctx *mapped_hctx = blk_mq_map_queue_type(hctx->queue,
3578 return mapped_hctx == hctx;
3581 static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
3583 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3584 struct blk_mq_hw_ctx, cpuhp_online);
3586 if (blk_mq_cpu_mapped_to_hctx(cpu, hctx))
3587 clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3592 * 'cpu' is going away. splice any existing rq_list entries from this
3593 * software queue to the hw queue dispatch list, and ensure that it
3596 static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
3598 struct blk_mq_hw_ctx *hctx;
3599 struct blk_mq_ctx *ctx;
3601 enum hctx_type type;
3603 hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
3604 if (!blk_mq_cpu_mapped_to_hctx(cpu, hctx))
3607 ctx = __blk_mq_get_ctx(hctx->queue, cpu);
3610 spin_lock(&ctx->lock);
3611 if (!list_empty(&ctx->rq_lists[type])) {
3612 list_splice_init(&ctx->rq_lists[type], &tmp);
3613 blk_mq_hctx_clear_pending(hctx, ctx);
3615 spin_unlock(&ctx->lock);
3617 if (list_empty(&tmp))
3620 spin_lock(&hctx->lock);
3621 list_splice_tail_init(&tmp, &hctx->dispatch);
3622 spin_unlock(&hctx->lock);
3624 blk_mq_run_hw_queue(hctx, true);
3628 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
3630 if (!(hctx->flags & BLK_MQ_F_STACKING))
3631 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3632 &hctx->cpuhp_online);
3633 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
3638 * Before freeing hw queue, clearing the flush request reference in
3639 * tags->rqs[] for avoiding potential UAF.
3641 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
3642 unsigned int queue_depth, struct request *flush_rq)
3645 unsigned long flags;
3647 /* The hw queue may not be mapped yet */
3651 WARN_ON_ONCE(req_ref_read(flush_rq) != 0);
3653 for (i = 0; i < queue_depth; i++)
3654 cmpxchg(&tags->rqs[i], flush_rq, NULL);
3657 * Wait until all pending iteration is done.
3659 * Request reference is cleared and it is guaranteed to be observed
3660 * after the ->lock is released.
3662 spin_lock_irqsave(&tags->lock, flags);
3663 spin_unlock_irqrestore(&tags->lock, flags);
3666 /* hctx->ctxs will be freed in queue's release handler */
3667 static void blk_mq_exit_hctx(struct request_queue *q,
3668 struct blk_mq_tag_set *set,
3669 struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
3671 struct request *flush_rq = hctx->fq->flush_rq;
3673 if (blk_mq_hw_queue_mapped(hctx))
3674 blk_mq_tag_idle(hctx);
3676 if (blk_queue_init_done(q))
3677 blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
3678 set->queue_depth, flush_rq);
3679 if (set->ops->exit_request)
3680 set->ops->exit_request(set, flush_rq, hctx_idx);
3682 if (set->ops->exit_hctx)
3683 set->ops->exit_hctx(hctx, hctx_idx);
3685 blk_mq_remove_cpuhp(hctx);
3687 xa_erase(&q->hctx_table, hctx_idx);
3689 spin_lock(&q->unused_hctx_lock);
3690 list_add(&hctx->hctx_list, &q->unused_hctx_list);
3691 spin_unlock(&q->unused_hctx_lock);
3694 static void blk_mq_exit_hw_queues(struct request_queue *q,
3695 struct blk_mq_tag_set *set, int nr_queue)
3697 struct blk_mq_hw_ctx *hctx;
3700 queue_for_each_hw_ctx(q, hctx, i) {
3703 blk_mq_exit_hctx(q, set, hctx, i);
3707 static int blk_mq_init_hctx(struct request_queue *q,
3708 struct blk_mq_tag_set *set,
3709 struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
3711 hctx->queue_num = hctx_idx;
3713 if (!(hctx->flags & BLK_MQ_F_STACKING))
3714 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3715 &hctx->cpuhp_online);
3716 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
3718 hctx->tags = set->tags[hctx_idx];
3720 if (set->ops->init_hctx &&
3721 set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
3722 goto unregister_cpu_notifier;
3724 if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
3728 if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL))
3734 if (set->ops->exit_request)
3735 set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
3737 if (set->ops->exit_hctx)
3738 set->ops->exit_hctx(hctx, hctx_idx);
3739 unregister_cpu_notifier:
3740 blk_mq_remove_cpuhp(hctx);
3744 static struct blk_mq_hw_ctx *
3745 blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
3748 struct blk_mq_hw_ctx *hctx;
3749 gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
3751 hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node);
3753 goto fail_alloc_hctx;
3755 if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
3758 atomic_set(&hctx->nr_active, 0);
3759 if (node == NUMA_NO_NODE)
3760 node = set->numa_node;
3761 hctx->numa_node = node;
3763 INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
3764 spin_lock_init(&hctx->lock);
3765 INIT_LIST_HEAD(&hctx->dispatch);
3767 hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
3769 INIT_LIST_HEAD(&hctx->hctx_list);
3772 * Allocate space for all possible cpus to avoid allocation at
3775 hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
3780 if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
3781 gfp, node, false, false))
3785 spin_lock_init(&hctx->dispatch_wait_lock);
3786 init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
3787 INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
3789 hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
3793 blk_mq_hctx_kobj_init(hctx);
3798 sbitmap_free(&hctx->ctx_map);
3802 free_cpumask_var(hctx->cpumask);
3809 static void blk_mq_init_cpu_queues(struct request_queue *q,
3810 unsigned int nr_hw_queues)
3812 struct blk_mq_tag_set *set = q->tag_set;
3815 for_each_possible_cpu(i) {
3816 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
3817 struct blk_mq_hw_ctx *hctx;
3821 spin_lock_init(&__ctx->lock);
3822 for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
3823 INIT_LIST_HEAD(&__ctx->rq_lists[k]);
3828 * Set local node, IFF we have more than one hw queue. If
3829 * not, we remain on the home node of the device
3831 for (j = 0; j < set->nr_maps; j++) {
3832 hctx = blk_mq_map_queue_type(q, j, i);
3833 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
3834 hctx->numa_node = cpu_to_node(i);
3839 struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3840 unsigned int hctx_idx,
3843 struct blk_mq_tags *tags;
3846 tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags);
3850 ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
3852 blk_mq_free_rq_map(tags);
3859 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3862 if (blk_mq_is_shared_tags(set->flags)) {
3863 set->tags[hctx_idx] = set->shared_tags;
3868 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
3871 return set->tags[hctx_idx];
3874 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3875 struct blk_mq_tags *tags,
3876 unsigned int hctx_idx)
3879 blk_mq_free_rqs(set, tags, hctx_idx);
3880 blk_mq_free_rq_map(tags);
3884 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3885 unsigned int hctx_idx)
3887 if (!blk_mq_is_shared_tags(set->flags))
3888 blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx);
3890 set->tags[hctx_idx] = NULL;
3893 static void blk_mq_map_swqueue(struct request_queue *q)
3895 unsigned int j, hctx_idx;
3897 struct blk_mq_hw_ctx *hctx;
3898 struct blk_mq_ctx *ctx;
3899 struct blk_mq_tag_set *set = q->tag_set;
3901 queue_for_each_hw_ctx(q, hctx, i) {
3902 cpumask_clear(hctx->cpumask);
3904 hctx->dispatch_from = NULL;
3908 * Map software to hardware queues.
3910 * If the cpu isn't present, the cpu is mapped to first hctx.
3912 for_each_possible_cpu(i) {
3914 ctx = per_cpu_ptr(q->queue_ctx, i);
3915 for (j = 0; j < set->nr_maps; j++) {
3916 if (!set->map[j].nr_queues) {
3917 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3918 HCTX_TYPE_DEFAULT, i);
3921 hctx_idx = set->map[j].mq_map[i];
3922 /* unmapped hw queue can be remapped after CPU topo changed */
3923 if (!set->tags[hctx_idx] &&
3924 !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
3926 * If tags initialization fail for some hctx,
3927 * that hctx won't be brought online. In this
3928 * case, remap the current ctx to hctx[0] which
3929 * is guaranteed to always have tags allocated
3931 set->map[j].mq_map[i] = 0;
3934 hctx = blk_mq_map_queue_type(q, j, i);
3935 ctx->hctxs[j] = hctx;
3937 * If the CPU is already set in the mask, then we've
3938 * mapped this one already. This can happen if
3939 * devices share queues across queue maps.
3941 if (cpumask_test_cpu(i, hctx->cpumask))
3944 cpumask_set_cpu(i, hctx->cpumask);
3946 ctx->index_hw[hctx->type] = hctx->nr_ctx;
3947 hctx->ctxs[hctx->nr_ctx++] = ctx;
3950 * If the nr_ctx type overflows, we have exceeded the
3951 * amount of sw queues we can support.
3953 BUG_ON(!hctx->nr_ctx);
3956 for (; j < HCTX_MAX_TYPES; j++)
3957 ctx->hctxs[j] = blk_mq_map_queue_type(q,
3958 HCTX_TYPE_DEFAULT, i);
3961 queue_for_each_hw_ctx(q, hctx, i) {
3965 * If no software queues are mapped to this hardware queue,
3966 * disable it and free the request entries.
3968 if (!hctx->nr_ctx) {
3969 /* Never unmap queue 0. We need it as a
3970 * fallback in case of a new remap fails
3974 __blk_mq_free_map_and_rqs(set, i);
3980 hctx->tags = set->tags[i];
3981 WARN_ON(!hctx->tags);
3984 * Set the map size to the number of mapped software queues.
3985 * This is more accurate and more efficient than looping
3986 * over all possibly mapped software queues.
3988 sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
3991 * Rule out isolated CPUs from hctx->cpumask to avoid
3992 * running block kworker on isolated CPUs
3994 for_each_cpu(cpu, hctx->cpumask) {
3995 if (cpu_is_isolated(cpu))
3996 cpumask_clear_cpu(cpu, hctx->cpumask);
4000 * Initialize batch roundrobin counts
4002 hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
4003 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
4008 * Caller needs to ensure that we're either frozen/quiesced, or that
4009 * the queue isn't live yet.
4011 static void queue_set_hctx_shared(struct request_queue *q, bool shared)
4013 struct blk_mq_hw_ctx *hctx;
4016 queue_for_each_hw_ctx(q, hctx, i) {
4018 hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
4020 blk_mq_tag_idle(hctx);
4021 hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
4026 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
4029 struct request_queue *q;
4031 lockdep_assert_held(&set->tag_list_lock);
4033 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4034 blk_mq_freeze_queue(q);
4035 queue_set_hctx_shared(q, shared);
4036 blk_mq_unfreeze_queue(q);
4040 static void blk_mq_del_queue_tag_set(struct request_queue *q)
4042 struct blk_mq_tag_set *set = q->tag_set;
4044 mutex_lock(&set->tag_list_lock);
4045 list_del(&q->tag_set_list);
4046 if (list_is_singular(&set->tag_list)) {
4047 /* just transitioned to unshared */
4048 set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
4049 /* update existing queue */
4050 blk_mq_update_tag_set_shared(set, false);
4052 mutex_unlock(&set->tag_list_lock);
4053 INIT_LIST_HEAD(&q->tag_set_list);
4056 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
4057 struct request_queue *q)
4059 mutex_lock(&set->tag_list_lock);
4062 * Check to see if we're transitioning to shared (from 1 to 2 queues).
4064 if (!list_empty(&set->tag_list) &&
4065 !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
4066 set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
4067 /* update existing queue */
4068 blk_mq_update_tag_set_shared(set, true);
4070 if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
4071 queue_set_hctx_shared(q, true);
4072 list_add_tail(&q->tag_set_list, &set->tag_list);
4074 mutex_unlock(&set->tag_list_lock);
4077 /* All allocations will be freed in release handler of q->mq_kobj */
4078 static int blk_mq_alloc_ctxs(struct request_queue *q)
4080 struct blk_mq_ctxs *ctxs;
4083 ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
4087 ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
4088 if (!ctxs->queue_ctx)
4091 for_each_possible_cpu(cpu) {
4092 struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
4096 q->mq_kobj = &ctxs->kobj;
4097 q->queue_ctx = ctxs->queue_ctx;
4106 * It is the actual release handler for mq, but we do it from
4107 * request queue's release handler for avoiding use-after-free
4108 * and headache because q->mq_kobj shouldn't have been introduced,
4109 * but we can't group ctx/kctx kobj without it.
4111 void blk_mq_release(struct request_queue *q)
4113 struct blk_mq_hw_ctx *hctx, *next;
4116 queue_for_each_hw_ctx(q, hctx, i)
4117 WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
4119 /* all hctx are in .unused_hctx_list now */
4120 list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
4121 list_del_init(&hctx->hctx_list);
4122 kobject_put(&hctx->kobj);
4125 xa_destroy(&q->hctx_table);
4128 * release .mq_kobj and sw queue's kobject now because
4129 * both share lifetime with request queue.
4131 blk_mq_sysfs_deinit(q);
4134 static bool blk_mq_can_poll(struct blk_mq_tag_set *set)
4136 return set->nr_maps > HCTX_TYPE_POLL &&
4137 set->map[HCTX_TYPE_POLL].nr_queues;
4140 struct request_queue *blk_mq_alloc_queue(struct blk_mq_tag_set *set,
4141 struct queue_limits *lim, void *queuedata)
4143 struct queue_limits default_lim = { };
4144 struct request_queue *q;
4149 lim->features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT;
4150 if (blk_mq_can_poll(set))
4151 lim->features |= BLK_FEAT_POLL;
4153 q = blk_alloc_queue(lim, set->numa_node);
4156 q->queuedata = queuedata;
4157 ret = blk_mq_init_allocated_queue(set, q);
4160 return ERR_PTR(ret);
4164 EXPORT_SYMBOL(blk_mq_alloc_queue);
4167 * blk_mq_destroy_queue - shutdown a request queue
4168 * @q: request queue to shutdown
4170 * This shuts down a request queue allocated by blk_mq_alloc_queue(). All future
4171 * requests will be failed with -ENODEV. The caller is responsible for dropping
4172 * the reference from blk_mq_alloc_queue() by calling blk_put_queue().
4174 * Context: can sleep
4176 void blk_mq_destroy_queue(struct request_queue *q)
4178 WARN_ON_ONCE(!queue_is_mq(q));
4179 WARN_ON_ONCE(blk_queue_registered(q));
4183 blk_queue_flag_set(QUEUE_FLAG_DYING, q);
4184 blk_queue_start_drain(q);
4185 blk_mq_freeze_queue_wait(q);
4188 blk_mq_cancel_work_sync(q);
4189 blk_mq_exit_queue(q);
4191 EXPORT_SYMBOL(blk_mq_destroy_queue);
4193 struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set,
4194 struct queue_limits *lim, void *queuedata,
4195 struct lock_class_key *lkclass)
4197 struct request_queue *q;
4198 struct gendisk *disk;
4200 q = blk_mq_alloc_queue(set, lim, queuedata);
4204 disk = __alloc_disk_node(q, set->numa_node, lkclass);
4206 blk_mq_destroy_queue(q);
4208 return ERR_PTR(-ENOMEM);
4210 set_bit(GD_OWNS_QUEUE, &disk->state);
4213 EXPORT_SYMBOL(__blk_mq_alloc_disk);
4215 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
4216 struct lock_class_key *lkclass)
4218 struct gendisk *disk;
4220 if (!blk_get_queue(q))
4222 disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass);
4227 EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue);
4229 static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
4230 struct blk_mq_tag_set *set, struct request_queue *q,
4231 int hctx_idx, int node)
4233 struct blk_mq_hw_ctx *hctx = NULL, *tmp;
4235 /* reuse dead hctx first */
4236 spin_lock(&q->unused_hctx_lock);
4237 list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
4238 if (tmp->numa_node == node) {
4244 list_del_init(&hctx->hctx_list);
4245 spin_unlock(&q->unused_hctx_lock);
4248 hctx = blk_mq_alloc_hctx(q, set, node);
4252 if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
4258 kobject_put(&hctx->kobj);
4263 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
4264 struct request_queue *q)
4266 struct blk_mq_hw_ctx *hctx;
4269 /* protect against switching io scheduler */
4270 mutex_lock(&q->sysfs_lock);
4271 for (i = 0; i < set->nr_hw_queues; i++) {
4273 int node = blk_mq_get_hctx_node(set, i);
4274 struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i);
4277 old_node = old_hctx->numa_node;
4278 blk_mq_exit_hctx(q, set, old_hctx, i);
4281 if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) {
4284 pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
4286 hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node);
4287 WARN_ON_ONCE(!hctx);
4291 * Increasing nr_hw_queues fails. Free the newly allocated
4292 * hctxs and keep the previous q->nr_hw_queues.
4294 if (i != set->nr_hw_queues) {
4295 j = q->nr_hw_queues;
4298 q->nr_hw_queues = set->nr_hw_queues;
4301 xa_for_each_start(&q->hctx_table, j, hctx, j)
4302 blk_mq_exit_hctx(q, set, hctx, j);
4303 mutex_unlock(&q->sysfs_lock);
4306 int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
4307 struct request_queue *q)
4309 /* mark the queue as mq asap */
4310 q->mq_ops = set->ops;
4312 if (blk_mq_alloc_ctxs(q))
4315 /* init q->mq_kobj and sw queues' kobjects */
4316 blk_mq_sysfs_init(q);
4318 INIT_LIST_HEAD(&q->unused_hctx_list);
4319 spin_lock_init(&q->unused_hctx_lock);
4321 xa_init(&q->hctx_table);
4323 blk_mq_realloc_hw_ctxs(set, q);
4324 if (!q->nr_hw_queues)
4327 INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
4328 blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
4332 q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
4334 INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
4335 INIT_LIST_HEAD(&q->flush_list);
4336 INIT_LIST_HEAD(&q->requeue_list);
4337 spin_lock_init(&q->requeue_lock);
4339 q->nr_requests = set->queue_depth;
4341 blk_mq_init_cpu_queues(q, set->nr_hw_queues);
4342 blk_mq_add_queue_tag_set(set, q);
4343 blk_mq_map_swqueue(q);
4352 EXPORT_SYMBOL(blk_mq_init_allocated_queue);
4354 /* tags can _not_ be used after returning from blk_mq_exit_queue */
4355 void blk_mq_exit_queue(struct request_queue *q)
4357 struct blk_mq_tag_set *set = q->tag_set;
4359 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
4360 blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
4361 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
4362 blk_mq_del_queue_tag_set(q);
4365 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
4369 if (blk_mq_is_shared_tags(set->flags)) {
4370 set->shared_tags = blk_mq_alloc_map_and_rqs(set,
4373 if (!set->shared_tags)
4377 for (i = 0; i < set->nr_hw_queues; i++) {
4378 if (!__blk_mq_alloc_map_and_rqs(set, i))
4387 __blk_mq_free_map_and_rqs(set, i);
4389 if (blk_mq_is_shared_tags(set->flags)) {
4390 blk_mq_free_map_and_rqs(set, set->shared_tags,
4391 BLK_MQ_NO_HCTX_IDX);
4398 * Allocate the request maps associated with this tag_set. Note that this
4399 * may reduce the depth asked for, if memory is tight. set->queue_depth
4400 * will be updated to reflect the allocated depth.
4402 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
4407 depth = set->queue_depth;
4409 err = __blk_mq_alloc_rq_maps(set);
4413 set->queue_depth >>= 1;
4414 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
4418 } while (set->queue_depth);
4420 if (!set->queue_depth || err) {
4421 pr_err("blk-mq: failed to allocate request map\n");
4425 if (depth != set->queue_depth)
4426 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
4427 depth, set->queue_depth);
4432 static void blk_mq_update_queue_map(struct blk_mq_tag_set *set)
4435 * blk_mq_map_queues() and multiple .map_queues() implementations
4436 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
4437 * number of hardware queues.
4439 if (set->nr_maps == 1)
4440 set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
4442 if (set->ops->map_queues) {
4446 * transport .map_queues is usually done in the following
4449 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
4450 * mask = get_cpu_mask(queue)
4451 * for_each_cpu(cpu, mask)
4452 * set->map[x].mq_map[cpu] = queue;
4455 * When we need to remap, the table has to be cleared for
4456 * killing stale mapping since one CPU may not be mapped
4459 for (i = 0; i < set->nr_maps; i++)
4460 blk_mq_clear_mq_map(&set->map[i]);
4462 set->ops->map_queues(set);
4464 BUG_ON(set->nr_maps > 1);
4465 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
4469 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
4470 int new_nr_hw_queues)
4472 struct blk_mq_tags **new_tags;
4475 if (set->nr_hw_queues >= new_nr_hw_queues)
4478 new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
4479 GFP_KERNEL, set->numa_node);
4484 memcpy(new_tags, set->tags, set->nr_hw_queues *
4485 sizeof(*set->tags));
4487 set->tags = new_tags;
4489 for (i = set->nr_hw_queues; i < new_nr_hw_queues; i++) {
4490 if (!__blk_mq_alloc_map_and_rqs(set, i)) {
4491 while (--i >= set->nr_hw_queues)
4492 __blk_mq_free_map_and_rqs(set, i);
4499 set->nr_hw_queues = new_nr_hw_queues;
4504 * Alloc a tag set to be associated with one or more request queues.
4505 * May fail with EINVAL for various error conditions. May adjust the
4506 * requested depth down, if it's too large. In that case, the set
4507 * value will be stored in set->queue_depth.
4509 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
4513 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
4515 if (!set->nr_hw_queues)
4517 if (!set->queue_depth)
4519 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
4522 if (!set->ops->queue_rq)
4525 if (!set->ops->get_budget ^ !set->ops->put_budget)
4528 if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
4529 pr_info("blk-mq: reduced tag depth to %u\n",
4531 set->queue_depth = BLK_MQ_MAX_DEPTH;
4536 else if (set->nr_maps > HCTX_MAX_TYPES)
4540 * If a crashdump is active, then we are potentially in a very
4541 * memory constrained environment. Limit us to 64 tags to prevent
4542 * using too much memory.
4544 if (is_kdump_kernel())
4545 set->queue_depth = min(64U, set->queue_depth);
4548 * There is no use for more h/w queues than cpus if we just have
4551 if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
4552 set->nr_hw_queues = nr_cpu_ids;
4554 if (set->flags & BLK_MQ_F_BLOCKING) {
4555 set->srcu = kmalloc(sizeof(*set->srcu), GFP_KERNEL);
4558 ret = init_srcu_struct(set->srcu);
4564 set->tags = kcalloc_node(set->nr_hw_queues,
4565 sizeof(struct blk_mq_tags *), GFP_KERNEL,
4568 goto out_cleanup_srcu;
4570 for (i = 0; i < set->nr_maps; i++) {
4571 set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
4572 sizeof(set->map[i].mq_map[0]),
4573 GFP_KERNEL, set->numa_node);
4574 if (!set->map[i].mq_map)
4575 goto out_free_mq_map;
4576 set->map[i].nr_queues = set->nr_hw_queues;
4579 blk_mq_update_queue_map(set);
4581 ret = blk_mq_alloc_set_map_and_rqs(set);
4583 goto out_free_mq_map;
4585 mutex_init(&set->tag_list_lock);
4586 INIT_LIST_HEAD(&set->tag_list);
4591 for (i = 0; i < set->nr_maps; i++) {
4592 kfree(set->map[i].mq_map);
4593 set->map[i].mq_map = NULL;
4598 if (set->flags & BLK_MQ_F_BLOCKING)
4599 cleanup_srcu_struct(set->srcu);
4601 if (set->flags & BLK_MQ_F_BLOCKING)
4605 EXPORT_SYMBOL(blk_mq_alloc_tag_set);
4607 /* allocate and initialize a tagset for a simple single-queue device */
4608 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set,
4609 const struct blk_mq_ops *ops, unsigned int queue_depth,
4610 unsigned int set_flags)
4612 memset(set, 0, sizeof(*set));
4614 set->nr_hw_queues = 1;
4616 set->queue_depth = queue_depth;
4617 set->numa_node = NUMA_NO_NODE;
4618 set->flags = set_flags;
4619 return blk_mq_alloc_tag_set(set);
4621 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set);
4623 void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
4627 for (i = 0; i < set->nr_hw_queues; i++)
4628 __blk_mq_free_map_and_rqs(set, i);
4630 if (blk_mq_is_shared_tags(set->flags)) {
4631 blk_mq_free_map_and_rqs(set, set->shared_tags,
4632 BLK_MQ_NO_HCTX_IDX);
4635 for (j = 0; j < set->nr_maps; j++) {
4636 kfree(set->map[j].mq_map);
4637 set->map[j].mq_map = NULL;
4642 if (set->flags & BLK_MQ_F_BLOCKING) {
4643 cleanup_srcu_struct(set->srcu);
4647 EXPORT_SYMBOL(blk_mq_free_tag_set);
4649 int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
4651 struct blk_mq_tag_set *set = q->tag_set;
4652 struct blk_mq_hw_ctx *hctx;
4656 if (WARN_ON_ONCE(!q->mq_freeze_depth))
4662 if (q->nr_requests == nr)
4665 blk_mq_quiesce_queue(q);
4668 queue_for_each_hw_ctx(q, hctx, i) {
4672 * If we're using an MQ scheduler, just update the scheduler
4673 * queue depth. This is similar to what the old code would do.
4675 if (hctx->sched_tags) {
4676 ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
4679 ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
4684 if (q->elevator && q->elevator->type->ops.depth_updated)
4685 q->elevator->type->ops.depth_updated(hctx);
4688 q->nr_requests = nr;
4689 if (blk_mq_is_shared_tags(set->flags)) {
4691 blk_mq_tag_update_sched_shared_tags(q);
4693 blk_mq_tag_resize_shared_tags(set, nr);
4697 blk_mq_unquiesce_queue(q);
4703 * request_queue and elevator_type pair.
4704 * It is just used by __blk_mq_update_nr_hw_queues to cache
4705 * the elevator_type associated with a request_queue.
4707 struct blk_mq_qe_pair {
4708 struct list_head node;
4709 struct request_queue *q;
4710 struct elevator_type *type;
4714 * Cache the elevator_type in qe pair list and switch the
4715 * io scheduler to 'none'
4717 static bool blk_mq_elv_switch_none(struct list_head *head,
4718 struct request_queue *q)
4720 struct blk_mq_qe_pair *qe;
4722 qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
4726 /* q->elevator needs protection from ->sysfs_lock */
4727 mutex_lock(&q->sysfs_lock);
4729 /* the check has to be done with holding sysfs_lock */
4735 INIT_LIST_HEAD(&qe->node);
4737 qe->type = q->elevator->type;
4738 /* keep a reference to the elevator module as we'll switch back */
4739 __elevator_get(qe->type);
4740 list_add(&qe->node, head);
4741 elevator_disable(q);
4743 mutex_unlock(&q->sysfs_lock);
4748 static struct blk_mq_qe_pair *blk_lookup_qe_pair(struct list_head *head,
4749 struct request_queue *q)
4751 struct blk_mq_qe_pair *qe;
4753 list_for_each_entry(qe, head, node)
4760 static void blk_mq_elv_switch_back(struct list_head *head,
4761 struct request_queue *q)
4763 struct blk_mq_qe_pair *qe;
4764 struct elevator_type *t;
4766 qe = blk_lookup_qe_pair(head, q);
4770 list_del(&qe->node);
4773 mutex_lock(&q->sysfs_lock);
4774 elevator_switch(q, t);
4775 /* drop the reference acquired in blk_mq_elv_switch_none */
4777 mutex_unlock(&q->sysfs_lock);
4780 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
4783 struct request_queue *q;
4785 int prev_nr_hw_queues = set->nr_hw_queues;
4788 lockdep_assert_held(&set->tag_list_lock);
4790 if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
4791 nr_hw_queues = nr_cpu_ids;
4792 if (nr_hw_queues < 1)
4794 if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
4797 list_for_each_entry(q, &set->tag_list, tag_set_list)
4798 blk_mq_freeze_queue(q);
4800 * Switch IO scheduler to 'none', cleaning up the data associated
4801 * with the previous scheduler. We will switch back once we are done
4802 * updating the new sw to hw queue mappings.
4804 list_for_each_entry(q, &set->tag_list, tag_set_list)
4805 if (!blk_mq_elv_switch_none(&head, q))
4808 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4809 blk_mq_debugfs_unregister_hctxs(q);
4810 blk_mq_sysfs_unregister_hctxs(q);
4813 if (blk_mq_realloc_tag_set_tags(set, nr_hw_queues) < 0)
4817 blk_mq_update_queue_map(set);
4818 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4819 struct queue_limits lim;
4821 blk_mq_realloc_hw_ctxs(set, q);
4823 if (q->nr_hw_queues != set->nr_hw_queues) {
4824 int i = prev_nr_hw_queues;
4826 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4827 nr_hw_queues, prev_nr_hw_queues);
4828 for (; i < set->nr_hw_queues; i++)
4829 __blk_mq_free_map_and_rqs(set, i);
4831 set->nr_hw_queues = prev_nr_hw_queues;
4834 lim = queue_limits_start_update(q);
4835 if (blk_mq_can_poll(set))
4836 lim.features |= BLK_FEAT_POLL;
4838 lim.features &= ~BLK_FEAT_POLL;
4839 if (queue_limits_commit_update(q, &lim) < 0)
4840 pr_warn("updating the poll flag failed\n");
4841 blk_mq_map_swqueue(q);
4845 list_for_each_entry(q, &set->tag_list, tag_set_list) {
4846 blk_mq_sysfs_register_hctxs(q);
4847 blk_mq_debugfs_register_hctxs(q);
4851 list_for_each_entry(q, &set->tag_list, tag_set_list)
4852 blk_mq_elv_switch_back(&head, q);
4854 list_for_each_entry(q, &set->tag_list, tag_set_list)
4855 blk_mq_unfreeze_queue(q);
4857 /* Free the excess tags when nr_hw_queues shrink. */
4858 for (i = set->nr_hw_queues; i < prev_nr_hw_queues; i++)
4859 __blk_mq_free_map_and_rqs(set, i);
4862 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
4864 mutex_lock(&set->tag_list_lock);
4865 __blk_mq_update_nr_hw_queues(set, nr_hw_queues);
4866 mutex_unlock(&set->tag_list_lock);
4868 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
4870 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
4871 struct io_comp_batch *iob, unsigned int flags)
4873 long state = get_current_state();
4877 ret = q->mq_ops->poll(hctx, iob);
4879 __set_current_state(TASK_RUNNING);
4883 if (signal_pending_state(state, current))
4884 __set_current_state(TASK_RUNNING);
4885 if (task_is_running(current))
4888 if (ret < 0 || (flags & BLK_POLL_ONESHOT))
4891 } while (!need_resched());
4893 __set_current_state(TASK_RUNNING);
4897 int blk_mq_poll(struct request_queue *q, blk_qc_t cookie,
4898 struct io_comp_batch *iob, unsigned int flags)
4900 struct blk_mq_hw_ctx *hctx = xa_load(&q->hctx_table, cookie);
4902 return blk_hctx_poll(q, hctx, iob, flags);
4905 int blk_rq_poll(struct request *rq, struct io_comp_batch *iob,
4906 unsigned int poll_flags)
4908 struct request_queue *q = rq->q;
4911 if (!blk_rq_is_poll(rq))
4913 if (!percpu_ref_tryget(&q->q_usage_counter))
4916 ret = blk_hctx_poll(q, rq->mq_hctx, iob, poll_flags);
4921 EXPORT_SYMBOL_GPL(blk_rq_poll);
4923 unsigned int blk_mq_rq_cpu(struct request *rq)
4925 return rq->mq_ctx->cpu;
4927 EXPORT_SYMBOL(blk_mq_rq_cpu);
4929 void blk_mq_cancel_work_sync(struct request_queue *q)
4931 struct blk_mq_hw_ctx *hctx;
4934 cancel_delayed_work_sync(&q->requeue_work);
4936 queue_for_each_hw_ctx(q, hctx, i)
4937 cancel_delayed_work_sync(&hctx->run_work);
4940 static int __init blk_mq_init(void)
4944 for_each_possible_cpu(i)
4945 init_llist_head(&per_cpu(blk_cpu_done, i));
4946 for_each_possible_cpu(i)
4947 INIT_CSD(&per_cpu(blk_cpu_csd, i),
4948 __blk_mq_complete_request_remote, NULL);
4949 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
4951 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
4952 "block/softirq:dead", NULL,
4953 blk_softirq_cpu_dead);
4954 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
4955 blk_mq_hctx_notify_dead);
4956 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
4957 blk_mq_hctx_notify_online,
4958 blk_mq_hctx_notify_offline);
4961 subsys_initcall(blk_mq_init);