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/kmemleak.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <linux/workqueue.h>
18 #include <linux/smp.h>
19 #include <linux/llist.h>
20 #include <linux/list_sort.h>
21 #include <linux/cpu.h>
22 #include <linux/cache.h>
23 #include <linux/sched/sysctl.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>
31 #include <trace/events/block.h>
33 #include <linux/blk-mq.h>
34 #include <linux/t10-pi.h>
37 #include "blk-mq-debugfs.h"
38 #include "blk-mq-tag.h"
41 #include "blk-mq-sched.h"
42 #include "blk-rq-qos.h"
44 static DEFINE_PER_CPU(struct list_head
, blk_cpu_done
);
46 static void blk_mq_poll_stats_start(struct request_queue
*q
);
47 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
);
49 static int blk_mq_poll_stats_bkt(const struct request
*rq
)
51 int ddir
, sectors
, bucket
;
53 ddir
= rq_data_dir(rq
);
54 sectors
= blk_rq_stats_sectors(rq
);
56 bucket
= ddir
+ 2 * ilog2(sectors
);
60 else if (bucket
>= BLK_MQ_POLL_STATS_BKTS
)
61 return ddir
+ BLK_MQ_POLL_STATS_BKTS
- 2;
67 * Check if any of the ctx, dispatch list or elevator
68 * have pending work in this hardware queue.
70 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
72 return !list_empty_careful(&hctx
->dispatch
) ||
73 sbitmap_any_bit_set(&hctx
->ctx_map
) ||
74 blk_mq_sched_has_work(hctx
);
78 * Mark this ctx as having pending work in this hardware queue
80 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
81 struct blk_mq_ctx
*ctx
)
83 const int bit
= ctx
->index_hw
[hctx
->type
];
85 if (!sbitmap_test_bit(&hctx
->ctx_map
, bit
))
86 sbitmap_set_bit(&hctx
->ctx_map
, bit
);
89 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
90 struct blk_mq_ctx
*ctx
)
92 const int bit
= ctx
->index_hw
[hctx
->type
];
94 sbitmap_clear_bit(&hctx
->ctx_map
, bit
);
98 struct hd_struct
*part
;
99 unsigned int inflight
[2];
102 static bool blk_mq_check_inflight(struct blk_mq_hw_ctx
*hctx
,
103 struct request
*rq
, void *priv
,
106 struct mq_inflight
*mi
= priv
;
108 if (rq
->part
== mi
->part
)
109 mi
->inflight
[rq_data_dir(rq
)]++;
114 unsigned int blk_mq_in_flight(struct request_queue
*q
, struct hd_struct
*part
)
116 struct mq_inflight mi
= { .part
= part
};
118 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
120 return mi
.inflight
[0] + mi
.inflight
[1];
123 void blk_mq_in_flight_rw(struct request_queue
*q
, struct hd_struct
*part
,
124 unsigned int inflight
[2])
126 struct mq_inflight mi
= { .part
= part
};
128 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
129 inflight
[0] = mi
.inflight
[0];
130 inflight
[1] = mi
.inflight
[1];
133 void blk_freeze_queue_start(struct request_queue
*q
)
135 mutex_lock(&q
->mq_freeze_lock
);
136 if (++q
->mq_freeze_depth
== 1) {
137 percpu_ref_kill(&q
->q_usage_counter
);
138 mutex_unlock(&q
->mq_freeze_lock
);
140 blk_mq_run_hw_queues(q
, false);
142 mutex_unlock(&q
->mq_freeze_lock
);
145 EXPORT_SYMBOL_GPL(blk_freeze_queue_start
);
147 void blk_mq_freeze_queue_wait(struct request_queue
*q
)
149 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->q_usage_counter
));
151 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait
);
153 int blk_mq_freeze_queue_wait_timeout(struct request_queue
*q
,
154 unsigned long timeout
)
156 return wait_event_timeout(q
->mq_freeze_wq
,
157 percpu_ref_is_zero(&q
->q_usage_counter
),
160 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout
);
163 * Guarantee no request is in use, so we can change any data structure of
164 * the queue afterward.
166 void blk_freeze_queue(struct request_queue
*q
)
169 * In the !blk_mq case we are only calling this to kill the
170 * q_usage_counter, otherwise this increases the freeze depth
171 * and waits for it to return to zero. For this reason there is
172 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
173 * exported to drivers as the only user for unfreeze is blk_mq.
175 blk_freeze_queue_start(q
);
176 blk_mq_freeze_queue_wait(q
);
179 void blk_mq_freeze_queue(struct request_queue
*q
)
182 * ...just an alias to keep freeze and unfreeze actions balanced
183 * in the blk_mq_* namespace
187 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
189 void blk_mq_unfreeze_queue(struct request_queue
*q
)
191 mutex_lock(&q
->mq_freeze_lock
);
192 q
->mq_freeze_depth
--;
193 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
194 if (!q
->mq_freeze_depth
) {
195 percpu_ref_resurrect(&q
->q_usage_counter
);
196 wake_up_all(&q
->mq_freeze_wq
);
198 mutex_unlock(&q
->mq_freeze_lock
);
200 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
203 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
204 * mpt3sas driver such that this function can be removed.
206 void blk_mq_quiesce_queue_nowait(struct request_queue
*q
)
208 blk_queue_flag_set(QUEUE_FLAG_QUIESCED
, q
);
210 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait
);
213 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
216 * Note: this function does not prevent that the struct request end_io()
217 * callback function is invoked. Once this function is returned, we make
218 * sure no dispatch can happen until the queue is unquiesced via
219 * blk_mq_unquiesce_queue().
221 void blk_mq_quiesce_queue(struct request_queue
*q
)
223 struct blk_mq_hw_ctx
*hctx
;
227 blk_mq_quiesce_queue_nowait(q
);
229 queue_for_each_hw_ctx(q
, hctx
, i
) {
230 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
231 synchronize_srcu(hctx
->srcu
);
238 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue
);
241 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
244 * This function recovers queue into the state before quiescing
245 * which is done by blk_mq_quiesce_queue.
247 void blk_mq_unquiesce_queue(struct request_queue
*q
)
249 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED
, q
);
251 /* dispatch requests which are inserted during quiescing */
252 blk_mq_run_hw_queues(q
, true);
254 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue
);
256 void blk_mq_wake_waiters(struct request_queue
*q
)
258 struct blk_mq_hw_ctx
*hctx
;
261 queue_for_each_hw_ctx(q
, hctx
, i
)
262 if (blk_mq_hw_queue_mapped(hctx
))
263 blk_mq_tag_wakeup_all(hctx
->tags
, true);
267 * Only need start/end time stamping if we have iostat or
268 * blk stats enabled, or using an IO scheduler.
270 static inline bool blk_mq_need_time_stamp(struct request
*rq
)
272 return (rq
->rq_flags
& (RQF_IO_STAT
| RQF_STATS
)) || rq
->q
->elevator
;
275 static struct request
*blk_mq_rq_ctx_init(struct blk_mq_alloc_data
*data
,
276 unsigned int tag
, u64 alloc_time_ns
)
278 struct blk_mq_tags
*tags
= blk_mq_tags_from_data(data
);
279 struct request
*rq
= tags
->static_rqs
[tag
];
281 if (data
->q
->elevator
) {
282 rq
->tag
= BLK_MQ_NO_TAG
;
283 rq
->internal_tag
= tag
;
286 rq
->internal_tag
= BLK_MQ_NO_TAG
;
289 /* csd/requeue_work/fifo_time is initialized before use */
291 rq
->mq_ctx
= data
->ctx
;
292 rq
->mq_hctx
= data
->hctx
;
294 rq
->cmd_flags
= data
->cmd_flags
;
295 if (data
->flags
& BLK_MQ_REQ_PREEMPT
)
296 rq
->rq_flags
|= RQF_PREEMPT
;
297 if (blk_queue_io_stat(data
->q
))
298 rq
->rq_flags
|= RQF_IO_STAT
;
299 INIT_LIST_HEAD(&rq
->queuelist
);
300 INIT_HLIST_NODE(&rq
->hash
);
301 RB_CLEAR_NODE(&rq
->rb_node
);
304 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
305 rq
->alloc_time_ns
= alloc_time_ns
;
307 if (blk_mq_need_time_stamp(rq
))
308 rq
->start_time_ns
= ktime_get_ns();
310 rq
->start_time_ns
= 0;
311 rq
->io_start_time_ns
= 0;
312 rq
->stats_sectors
= 0;
313 rq
->nr_phys_segments
= 0;
314 #if defined(CONFIG_BLK_DEV_INTEGRITY)
315 rq
->nr_integrity_segments
= 0;
317 blk_crypto_rq_set_defaults(rq
);
318 /* tag was already set */
319 WRITE_ONCE(rq
->deadline
, 0);
324 rq
->end_io_data
= NULL
;
326 data
->ctx
->rq_dispatched
[op_is_sync(data
->cmd_flags
)]++;
327 refcount_set(&rq
->ref
, 1);
329 if (!op_is_flush(data
->cmd_flags
)) {
330 struct elevator_queue
*e
= data
->q
->elevator
;
333 if (e
&& e
->type
->ops
.prepare_request
) {
334 if (e
->type
->icq_cache
)
335 blk_mq_sched_assign_ioc(rq
);
337 e
->type
->ops
.prepare_request(rq
);
338 rq
->rq_flags
|= RQF_ELVPRIV
;
342 data
->hctx
->queued
++;
346 static struct request
*__blk_mq_alloc_request(struct blk_mq_alloc_data
*data
)
348 struct request_queue
*q
= data
->q
;
349 struct elevator_queue
*e
= q
->elevator
;
350 u64 alloc_time_ns
= 0;
353 /* alloc_time includes depth and tag waits */
354 if (blk_queue_rq_alloc_time(q
))
355 alloc_time_ns
= ktime_get_ns();
357 if (data
->cmd_flags
& REQ_NOWAIT
)
358 data
->flags
|= BLK_MQ_REQ_NOWAIT
;
362 * Flush requests are special and go directly to the
363 * dispatch list. Don't include reserved tags in the
364 * limiting, as it isn't useful.
366 if (!op_is_flush(data
->cmd_flags
) &&
367 e
->type
->ops
.limit_depth
&&
368 !(data
->flags
& BLK_MQ_REQ_RESERVED
))
369 e
->type
->ops
.limit_depth(data
->cmd_flags
, data
);
373 data
->ctx
= blk_mq_get_ctx(q
);
374 data
->hctx
= blk_mq_map_queue(q
, data
->cmd_flags
, data
->ctx
);
376 blk_mq_tag_busy(data
->hctx
);
379 * Waiting allocations only fail because of an inactive hctx. In that
380 * case just retry the hctx assignment and tag allocation as CPU hotplug
381 * should have migrated us to an online CPU by now.
383 tag
= blk_mq_get_tag(data
);
384 if (tag
== BLK_MQ_NO_TAG
) {
385 if (data
->flags
& BLK_MQ_REQ_NOWAIT
)
389 * Give up the CPU and sleep for a random short time to ensure
390 * that thread using a realtime scheduling class are migrated
391 * off the CPU, and thus off the hctx that is going away.
396 return blk_mq_rq_ctx_init(data
, tag
, alloc_time_ns
);
399 struct request
*blk_mq_alloc_request(struct request_queue
*q
, unsigned int op
,
400 blk_mq_req_flags_t flags
)
402 struct blk_mq_alloc_data data
= {
410 ret
= blk_queue_enter(q
, flags
);
414 rq
= __blk_mq_alloc_request(&data
);
418 rq
->__sector
= (sector_t
) -1;
419 rq
->bio
= rq
->biotail
= NULL
;
423 return ERR_PTR(-EWOULDBLOCK
);
425 EXPORT_SYMBOL(blk_mq_alloc_request
);
427 struct request
*blk_mq_alloc_request_hctx(struct request_queue
*q
,
428 unsigned int op
, blk_mq_req_flags_t flags
, unsigned int hctx_idx
)
430 struct blk_mq_alloc_data data
= {
435 u64 alloc_time_ns
= 0;
440 /* alloc_time includes depth and tag waits */
441 if (blk_queue_rq_alloc_time(q
))
442 alloc_time_ns
= ktime_get_ns();
445 * If the tag allocator sleeps we could get an allocation for a
446 * different hardware context. No need to complicate the low level
447 * allocator for this for the rare use case of a command tied to
450 if (WARN_ON_ONCE(!(flags
& (BLK_MQ_REQ_NOWAIT
| BLK_MQ_REQ_RESERVED
))))
451 return ERR_PTR(-EINVAL
);
453 if (hctx_idx
>= q
->nr_hw_queues
)
454 return ERR_PTR(-EIO
);
456 ret
= blk_queue_enter(q
, flags
);
461 * Check if the hardware context is actually mapped to anything.
462 * If not tell the caller that it should skip this queue.
465 data
.hctx
= q
->queue_hw_ctx
[hctx_idx
];
466 if (!blk_mq_hw_queue_mapped(data
.hctx
))
468 cpu
= cpumask_first_and(data
.hctx
->cpumask
, cpu_online_mask
);
469 data
.ctx
= __blk_mq_get_ctx(q
, cpu
);
472 blk_mq_tag_busy(data
.hctx
);
475 tag
= blk_mq_get_tag(&data
);
476 if (tag
== BLK_MQ_NO_TAG
)
478 return blk_mq_rq_ctx_init(&data
, tag
, alloc_time_ns
);
484 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx
);
486 static void __blk_mq_free_request(struct request
*rq
)
488 struct request_queue
*q
= rq
->q
;
489 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
490 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
491 const int sched_tag
= rq
->internal_tag
;
493 blk_crypto_free_request(rq
);
494 blk_pm_mark_last_busy(rq
);
496 if (rq
->tag
!= BLK_MQ_NO_TAG
)
497 blk_mq_put_tag(hctx
->tags
, ctx
, rq
->tag
);
498 if (sched_tag
!= BLK_MQ_NO_TAG
)
499 blk_mq_put_tag(hctx
->sched_tags
, ctx
, sched_tag
);
500 blk_mq_sched_restart(hctx
);
504 void blk_mq_free_request(struct request
*rq
)
506 struct request_queue
*q
= rq
->q
;
507 struct elevator_queue
*e
= q
->elevator
;
508 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
509 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
511 if (rq
->rq_flags
& RQF_ELVPRIV
) {
512 if (e
&& e
->type
->ops
.finish_request
)
513 e
->type
->ops
.finish_request(rq
);
515 put_io_context(rq
->elv
.icq
->ioc
);
520 ctx
->rq_completed
[rq_is_sync(rq
)]++;
521 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
)
522 atomic_dec(&hctx
->nr_active
);
524 if (unlikely(laptop_mode
&& !blk_rq_is_passthrough(rq
)))
525 laptop_io_completion(q
->backing_dev_info
);
529 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
530 if (refcount_dec_and_test(&rq
->ref
))
531 __blk_mq_free_request(rq
);
533 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
535 inline void __blk_mq_end_request(struct request
*rq
, blk_status_t error
)
539 if (blk_mq_need_time_stamp(rq
))
540 now
= ktime_get_ns();
542 if (rq
->rq_flags
& RQF_STATS
) {
543 blk_mq_poll_stats_start(rq
->q
);
544 blk_stat_add(rq
, now
);
547 blk_mq_sched_completed_request(rq
, now
);
549 blk_account_io_done(rq
, now
);
552 rq_qos_done(rq
->q
, rq
);
553 rq
->end_io(rq
, error
);
555 blk_mq_free_request(rq
);
558 EXPORT_SYMBOL(__blk_mq_end_request
);
560 void blk_mq_end_request(struct request
*rq
, blk_status_t error
)
562 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
564 __blk_mq_end_request(rq
, error
);
566 EXPORT_SYMBOL(blk_mq_end_request
);
569 * Softirq action handler - move entries to local list and loop over them
570 * while passing them to the queue registered handler.
572 static __latent_entropy
void blk_done_softirq(struct softirq_action
*h
)
574 struct list_head
*cpu_list
, local_list
;
577 cpu_list
= this_cpu_ptr(&blk_cpu_done
);
578 list_replace_init(cpu_list
, &local_list
);
581 while (!list_empty(&local_list
)) {
584 rq
= list_entry(local_list
.next
, struct request
, ipi_list
);
585 list_del_init(&rq
->ipi_list
);
586 rq
->q
->mq_ops
->complete(rq
);
590 static void blk_mq_trigger_softirq(struct request
*rq
)
592 struct list_head
*list
;
595 local_irq_save(flags
);
596 list
= this_cpu_ptr(&blk_cpu_done
);
597 list_add_tail(&rq
->ipi_list
, list
);
600 * If the list only contains our just added request, signal a raise of
601 * the softirq. If there are already entries there, someone already
602 * raised the irq but it hasn't run yet.
604 if (list
->next
== &rq
->ipi_list
)
605 raise_softirq_irqoff(BLOCK_SOFTIRQ
);
606 local_irq_restore(flags
);
609 static int blk_softirq_cpu_dead(unsigned int cpu
)
612 * If a CPU goes away, splice its entries to the current CPU
613 * and trigger a run of the softirq
616 list_splice_init(&per_cpu(blk_cpu_done
, cpu
),
617 this_cpu_ptr(&blk_cpu_done
));
618 raise_softirq_irqoff(BLOCK_SOFTIRQ
);
625 static void __blk_mq_complete_request_remote(void *data
)
627 struct request
*rq
= data
;
630 * For most of single queue controllers, there is only one irq vector
631 * for handling I/O completion, and the only irq's affinity is set
632 * to all possible CPUs. On most of ARCHs, this affinity means the irq
633 * is handled on one specific CPU.
635 * So complete I/O requests in softirq context in case of single queue
636 * devices to avoid degrading I/O performance due to irqsoff latency.
638 if (rq
->q
->nr_hw_queues
== 1)
639 blk_mq_trigger_softirq(rq
);
641 rq
->q
->mq_ops
->complete(rq
);
644 static inline bool blk_mq_complete_need_ipi(struct request
*rq
)
646 int cpu
= raw_smp_processor_id();
648 if (!IS_ENABLED(CONFIG_SMP
) ||
649 !test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
))
652 /* same CPU or cache domain? Complete locally */
653 if (cpu
== rq
->mq_ctx
->cpu
||
654 (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
) &&
655 cpus_share_cache(cpu
, rq
->mq_ctx
->cpu
)))
658 /* don't try to IPI to an offline CPU */
659 return cpu_online(rq
->mq_ctx
->cpu
);
662 bool blk_mq_complete_request_remote(struct request
*rq
)
664 WRITE_ONCE(rq
->state
, MQ_RQ_COMPLETE
);
667 * For a polled request, always complete locallly, it's pointless
668 * to redirect the completion.
670 if (rq
->cmd_flags
& REQ_HIPRI
)
673 if (blk_mq_complete_need_ipi(rq
)) {
674 rq
->csd
.func
= __blk_mq_complete_request_remote
;
677 smp_call_function_single_async(rq
->mq_ctx
->cpu
, &rq
->csd
);
679 if (rq
->q
->nr_hw_queues
> 1)
681 blk_mq_trigger_softirq(rq
);
686 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote
);
689 * blk_mq_complete_request - end I/O on a request
690 * @rq: the request being processed
693 * Complete a request by scheduling the ->complete_rq operation.
695 void blk_mq_complete_request(struct request
*rq
)
697 if (!blk_mq_complete_request_remote(rq
))
698 rq
->q
->mq_ops
->complete(rq
);
700 EXPORT_SYMBOL(blk_mq_complete_request
);
702 static void hctx_unlock(struct blk_mq_hw_ctx
*hctx
, int srcu_idx
)
703 __releases(hctx
->srcu
)
705 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
))
708 srcu_read_unlock(hctx
->srcu
, srcu_idx
);
711 static void hctx_lock(struct blk_mq_hw_ctx
*hctx
, int *srcu_idx
)
712 __acquires(hctx
->srcu
)
714 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
715 /* shut up gcc false positive */
719 *srcu_idx
= srcu_read_lock(hctx
->srcu
);
723 * blk_mq_start_request - Start processing a request
724 * @rq: Pointer to request to be started
726 * Function used by device drivers to notify the block layer that a request
727 * is going to be processed now, so blk layer can do proper initializations
728 * such as starting the timeout timer.
730 void blk_mq_start_request(struct request
*rq
)
732 struct request_queue
*q
= rq
->q
;
734 trace_block_rq_issue(q
, rq
);
736 if (test_bit(QUEUE_FLAG_STATS
, &q
->queue_flags
)) {
737 rq
->io_start_time_ns
= ktime_get_ns();
738 rq
->stats_sectors
= blk_rq_sectors(rq
);
739 rq
->rq_flags
|= RQF_STATS
;
743 WARN_ON_ONCE(blk_mq_rq_state(rq
) != MQ_RQ_IDLE
);
746 WRITE_ONCE(rq
->state
, MQ_RQ_IN_FLIGHT
);
748 #ifdef CONFIG_BLK_DEV_INTEGRITY
749 if (blk_integrity_rq(rq
) && req_op(rq
) == REQ_OP_WRITE
)
750 q
->integrity
.profile
->prepare_fn(rq
);
753 EXPORT_SYMBOL(blk_mq_start_request
);
755 static void __blk_mq_requeue_request(struct request
*rq
)
757 struct request_queue
*q
= rq
->q
;
759 blk_mq_put_driver_tag(rq
);
761 trace_block_rq_requeue(q
, rq
);
762 rq_qos_requeue(q
, rq
);
764 if (blk_mq_request_started(rq
)) {
765 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
766 rq
->rq_flags
&= ~RQF_TIMED_OUT
;
770 void blk_mq_requeue_request(struct request
*rq
, bool kick_requeue_list
)
772 __blk_mq_requeue_request(rq
);
774 /* this request will be re-inserted to io scheduler queue */
775 blk_mq_sched_requeue_request(rq
);
777 BUG_ON(!list_empty(&rq
->queuelist
));
778 blk_mq_add_to_requeue_list(rq
, true, kick_requeue_list
);
780 EXPORT_SYMBOL(blk_mq_requeue_request
);
782 static void blk_mq_requeue_work(struct work_struct
*work
)
784 struct request_queue
*q
=
785 container_of(work
, struct request_queue
, requeue_work
.work
);
787 struct request
*rq
, *next
;
789 spin_lock_irq(&q
->requeue_lock
);
790 list_splice_init(&q
->requeue_list
, &rq_list
);
791 spin_unlock_irq(&q
->requeue_lock
);
793 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
794 if (!(rq
->rq_flags
& (RQF_SOFTBARRIER
| RQF_DONTPREP
)))
797 rq
->rq_flags
&= ~RQF_SOFTBARRIER
;
798 list_del_init(&rq
->queuelist
);
800 * If RQF_DONTPREP, rq has contained some driver specific
801 * data, so insert it to hctx dispatch list to avoid any
804 if (rq
->rq_flags
& RQF_DONTPREP
)
805 blk_mq_request_bypass_insert(rq
, false, false);
807 blk_mq_sched_insert_request(rq
, true, false, false);
810 while (!list_empty(&rq_list
)) {
811 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
812 list_del_init(&rq
->queuelist
);
813 blk_mq_sched_insert_request(rq
, false, false, false);
816 blk_mq_run_hw_queues(q
, false);
819 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
,
820 bool kick_requeue_list
)
822 struct request_queue
*q
= rq
->q
;
826 * We abuse this flag that is otherwise used by the I/O scheduler to
827 * request head insertion from the workqueue.
829 BUG_ON(rq
->rq_flags
& RQF_SOFTBARRIER
);
831 spin_lock_irqsave(&q
->requeue_lock
, flags
);
833 rq
->rq_flags
|= RQF_SOFTBARRIER
;
834 list_add(&rq
->queuelist
, &q
->requeue_list
);
836 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
838 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
840 if (kick_requeue_list
)
841 blk_mq_kick_requeue_list(q
);
844 void blk_mq_kick_requeue_list(struct request_queue
*q
)
846 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
, 0);
848 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
850 void blk_mq_delay_kick_requeue_list(struct request_queue
*q
,
853 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
,
854 msecs_to_jiffies(msecs
));
856 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list
);
858 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
860 if (tag
< tags
->nr_tags
) {
861 prefetch(tags
->rqs
[tag
]);
862 return tags
->rqs
[tag
];
867 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
869 static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
870 void *priv
, bool reserved
)
873 * If we find a request that isn't idle and the queue matches,
874 * we know the queue is busy. Return false to stop the iteration.
876 if (blk_mq_request_started(rq
) && rq
->q
== hctx
->queue
) {
886 bool blk_mq_queue_inflight(struct request_queue
*q
)
890 blk_mq_queue_tag_busy_iter(q
, blk_mq_rq_inflight
, &busy
);
893 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight
);
895 static void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
897 req
->rq_flags
|= RQF_TIMED_OUT
;
898 if (req
->q
->mq_ops
->timeout
) {
899 enum blk_eh_timer_return ret
;
901 ret
= req
->q
->mq_ops
->timeout(req
, reserved
);
902 if (ret
== BLK_EH_DONE
)
904 WARN_ON_ONCE(ret
!= BLK_EH_RESET_TIMER
);
910 static bool blk_mq_req_expired(struct request
*rq
, unsigned long *next
)
912 unsigned long deadline
;
914 if (blk_mq_rq_state(rq
) != MQ_RQ_IN_FLIGHT
)
916 if (rq
->rq_flags
& RQF_TIMED_OUT
)
919 deadline
= READ_ONCE(rq
->deadline
);
920 if (time_after_eq(jiffies
, deadline
))
925 else if (time_after(*next
, deadline
))
930 static bool blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
931 struct request
*rq
, void *priv
, bool reserved
)
933 unsigned long *next
= priv
;
936 * Just do a quick check if it is expired before locking the request in
937 * so we're not unnecessarilly synchronizing across CPUs.
939 if (!blk_mq_req_expired(rq
, next
))
943 * We have reason to believe the request may be expired. Take a
944 * reference on the request to lock this request lifetime into its
945 * currently allocated context to prevent it from being reallocated in
946 * the event the completion by-passes this timeout handler.
948 * If the reference was already released, then the driver beat the
949 * timeout handler to posting a natural completion.
951 if (!refcount_inc_not_zero(&rq
->ref
))
955 * The request is now locked and cannot be reallocated underneath the
956 * timeout handler's processing. Re-verify this exact request is truly
957 * expired; if it is not expired, then the request was completed and
958 * reallocated as a new request.
960 if (blk_mq_req_expired(rq
, next
))
961 blk_mq_rq_timed_out(rq
, reserved
);
963 if (is_flush_rq(rq
, hctx
))
965 else if (refcount_dec_and_test(&rq
->ref
))
966 __blk_mq_free_request(rq
);
971 static void blk_mq_timeout_work(struct work_struct
*work
)
973 struct request_queue
*q
=
974 container_of(work
, struct request_queue
, timeout_work
);
975 unsigned long next
= 0;
976 struct blk_mq_hw_ctx
*hctx
;
979 /* A deadlock might occur if a request is stuck requiring a
980 * timeout at the same time a queue freeze is waiting
981 * completion, since the timeout code would not be able to
982 * acquire the queue reference here.
984 * That's why we don't use blk_queue_enter here; instead, we use
985 * percpu_ref_tryget directly, because we need to be able to
986 * obtain a reference even in the short window between the queue
987 * starting to freeze, by dropping the first reference in
988 * blk_freeze_queue_start, and the moment the last request is
989 * consumed, marked by the instant q_usage_counter reaches
992 if (!percpu_ref_tryget(&q
->q_usage_counter
))
995 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_expired
, &next
);
998 mod_timer(&q
->timeout
, next
);
1001 * Request timeouts are handled as a forward rolling timer. If
1002 * we end up here it means that no requests are pending and
1003 * also that no request has been pending for a while. Mark
1004 * each hctx as idle.
1006 queue_for_each_hw_ctx(q
, hctx
, i
) {
1007 /* the hctx may be unmapped, so check it here */
1008 if (blk_mq_hw_queue_mapped(hctx
))
1009 blk_mq_tag_idle(hctx
);
1015 struct flush_busy_ctx_data
{
1016 struct blk_mq_hw_ctx
*hctx
;
1017 struct list_head
*list
;
1020 static bool flush_busy_ctx(struct sbitmap
*sb
, unsigned int bitnr
, void *data
)
1022 struct flush_busy_ctx_data
*flush_data
= data
;
1023 struct blk_mq_hw_ctx
*hctx
= flush_data
->hctx
;
1024 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
1025 enum hctx_type type
= hctx
->type
;
1027 spin_lock(&ctx
->lock
);
1028 list_splice_tail_init(&ctx
->rq_lists
[type
], flush_data
->list
);
1029 sbitmap_clear_bit(sb
, bitnr
);
1030 spin_unlock(&ctx
->lock
);
1035 * Process software queues that have been marked busy, splicing them
1036 * to the for-dispatch
1038 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
1040 struct flush_busy_ctx_data data
= {
1045 sbitmap_for_each_set(&hctx
->ctx_map
, flush_busy_ctx
, &data
);
1047 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs
);
1049 struct dispatch_rq_data
{
1050 struct blk_mq_hw_ctx
*hctx
;
1054 static bool dispatch_rq_from_ctx(struct sbitmap
*sb
, unsigned int bitnr
,
1057 struct dispatch_rq_data
*dispatch_data
= data
;
1058 struct blk_mq_hw_ctx
*hctx
= dispatch_data
->hctx
;
1059 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
1060 enum hctx_type type
= hctx
->type
;
1062 spin_lock(&ctx
->lock
);
1063 if (!list_empty(&ctx
->rq_lists
[type
])) {
1064 dispatch_data
->rq
= list_entry_rq(ctx
->rq_lists
[type
].next
);
1065 list_del_init(&dispatch_data
->rq
->queuelist
);
1066 if (list_empty(&ctx
->rq_lists
[type
]))
1067 sbitmap_clear_bit(sb
, bitnr
);
1069 spin_unlock(&ctx
->lock
);
1071 return !dispatch_data
->rq
;
1074 struct request
*blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx
*hctx
,
1075 struct blk_mq_ctx
*start
)
1077 unsigned off
= start
? start
->index_hw
[hctx
->type
] : 0;
1078 struct dispatch_rq_data data
= {
1083 __sbitmap_for_each_set(&hctx
->ctx_map
, off
,
1084 dispatch_rq_from_ctx
, &data
);
1089 static inline unsigned int queued_to_index(unsigned int queued
)
1094 return min(BLK_MQ_MAX_DISPATCH_ORDER
- 1, ilog2(queued
) + 1);
1097 static bool __blk_mq_get_driver_tag(struct request
*rq
)
1099 struct sbitmap_queue
*bt
= &rq
->mq_hctx
->tags
->bitmap_tags
;
1100 unsigned int tag_offset
= rq
->mq_hctx
->tags
->nr_reserved_tags
;
1103 blk_mq_tag_busy(rq
->mq_hctx
);
1105 if (blk_mq_tag_is_reserved(rq
->mq_hctx
->sched_tags
, rq
->internal_tag
)) {
1106 bt
= &rq
->mq_hctx
->tags
->breserved_tags
;
1110 if (!hctx_may_queue(rq
->mq_hctx
, bt
))
1112 tag
= __sbitmap_queue_get(bt
);
1113 if (tag
== BLK_MQ_NO_TAG
)
1116 rq
->tag
= tag
+ tag_offset
;
1120 static bool blk_mq_get_driver_tag(struct request
*rq
)
1122 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
1124 if (rq
->tag
== BLK_MQ_NO_TAG
&& !__blk_mq_get_driver_tag(rq
))
1127 if ((hctx
->flags
& BLK_MQ_F_TAG_SHARED
) &&
1128 !(rq
->rq_flags
& RQF_MQ_INFLIGHT
)) {
1129 rq
->rq_flags
|= RQF_MQ_INFLIGHT
;
1130 atomic_inc(&hctx
->nr_active
);
1132 hctx
->tags
->rqs
[rq
->tag
] = rq
;
1136 static int blk_mq_dispatch_wake(wait_queue_entry_t
*wait
, unsigned mode
,
1137 int flags
, void *key
)
1139 struct blk_mq_hw_ctx
*hctx
;
1141 hctx
= container_of(wait
, struct blk_mq_hw_ctx
, dispatch_wait
);
1143 spin_lock(&hctx
->dispatch_wait_lock
);
1144 if (!list_empty(&wait
->entry
)) {
1145 struct sbitmap_queue
*sbq
;
1147 list_del_init(&wait
->entry
);
1148 sbq
= &hctx
->tags
->bitmap_tags
;
1149 atomic_dec(&sbq
->ws_active
);
1151 spin_unlock(&hctx
->dispatch_wait_lock
);
1153 blk_mq_run_hw_queue(hctx
, true);
1158 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1159 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1160 * restart. For both cases, take care to check the condition again after
1161 * marking us as waiting.
1163 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx
*hctx
,
1166 struct sbitmap_queue
*sbq
= &hctx
->tags
->bitmap_tags
;
1167 struct wait_queue_head
*wq
;
1168 wait_queue_entry_t
*wait
;
1171 if (!(hctx
->flags
& BLK_MQ_F_TAG_SHARED
)) {
1172 blk_mq_sched_mark_restart_hctx(hctx
);
1175 * It's possible that a tag was freed in the window between the
1176 * allocation failure and adding the hardware queue to the wait
1179 * Don't clear RESTART here, someone else could have set it.
1180 * At most this will cost an extra queue run.
1182 return blk_mq_get_driver_tag(rq
);
1185 wait
= &hctx
->dispatch_wait
;
1186 if (!list_empty_careful(&wait
->entry
))
1189 wq
= &bt_wait_ptr(sbq
, hctx
)->wait
;
1191 spin_lock_irq(&wq
->lock
);
1192 spin_lock(&hctx
->dispatch_wait_lock
);
1193 if (!list_empty(&wait
->entry
)) {
1194 spin_unlock(&hctx
->dispatch_wait_lock
);
1195 spin_unlock_irq(&wq
->lock
);
1199 atomic_inc(&sbq
->ws_active
);
1200 wait
->flags
&= ~WQ_FLAG_EXCLUSIVE
;
1201 __add_wait_queue(wq
, wait
);
1204 * It's possible that a tag was freed in the window between the
1205 * allocation failure and adding the hardware queue to the wait
1208 ret
= blk_mq_get_driver_tag(rq
);
1210 spin_unlock(&hctx
->dispatch_wait_lock
);
1211 spin_unlock_irq(&wq
->lock
);
1216 * We got a tag, remove ourselves from the wait queue to ensure
1217 * someone else gets the wakeup.
1219 list_del_init(&wait
->entry
);
1220 atomic_dec(&sbq
->ws_active
);
1221 spin_unlock(&hctx
->dispatch_wait_lock
);
1222 spin_unlock_irq(&wq
->lock
);
1227 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1228 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1230 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1231 * - EWMA is one simple way to compute running average value
1232 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1233 * - take 4 as factor for avoiding to get too small(0) result, and this
1234 * factor doesn't matter because EWMA decreases exponentially
1236 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx
*hctx
, bool busy
)
1240 if (hctx
->queue
->elevator
)
1243 ewma
= hctx
->dispatch_busy
;
1248 ewma
*= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
- 1;
1250 ewma
+= 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR
;
1251 ewma
/= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
;
1253 hctx
->dispatch_busy
= ewma
;
1256 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1258 static void blk_mq_handle_dev_resource(struct request
*rq
,
1259 struct list_head
*list
)
1261 struct request
*next
=
1262 list_first_entry_or_null(list
, struct request
, queuelist
);
1265 * If an I/O scheduler has been configured and we got a driver tag for
1266 * the next request already, free it.
1269 blk_mq_put_driver_tag(next
);
1271 list_add(&rq
->queuelist
, list
);
1272 __blk_mq_requeue_request(rq
);
1275 static void blk_mq_handle_zone_resource(struct request
*rq
,
1276 struct list_head
*zone_list
)
1279 * If we end up here it is because we cannot dispatch a request to a
1280 * specific zone due to LLD level zone-write locking or other zone
1281 * related resource not being available. In this case, set the request
1282 * aside in zone_list for retrying it later.
1284 list_add(&rq
->queuelist
, zone_list
);
1285 __blk_mq_requeue_request(rq
);
1288 enum prep_dispatch
{
1290 PREP_DISPATCH_NO_TAG
,
1291 PREP_DISPATCH_NO_BUDGET
,
1294 static enum prep_dispatch
blk_mq_prep_dispatch_rq(struct request
*rq
,
1297 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
1299 if (need_budget
&& !blk_mq_get_dispatch_budget(rq
->q
)) {
1300 blk_mq_put_driver_tag(rq
);
1301 return PREP_DISPATCH_NO_BUDGET
;
1304 if (!blk_mq_get_driver_tag(rq
)) {
1306 * The initial allocation attempt failed, so we need to
1307 * rerun the hardware queue when a tag is freed. The
1308 * waitqueue takes care of that. If the queue is run
1309 * before we add this entry back on the dispatch list,
1310 * we'll re-run it below.
1312 if (!blk_mq_mark_tag_wait(hctx
, rq
)) {
1314 * All budgets not got from this function will be put
1315 * together during handling partial dispatch
1318 blk_mq_put_dispatch_budget(rq
->q
);
1319 return PREP_DISPATCH_NO_TAG
;
1323 return PREP_DISPATCH_OK
;
1326 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1327 static void blk_mq_release_budgets(struct request_queue
*q
,
1328 unsigned int nr_budgets
)
1332 for (i
= 0; i
< nr_budgets
; i
++)
1333 blk_mq_put_dispatch_budget(q
);
1337 * Returns true if we did some work AND can potentially do more.
1339 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
,
1340 unsigned int nr_budgets
)
1342 enum prep_dispatch prep
;
1343 struct request_queue
*q
= hctx
->queue
;
1344 struct request
*rq
, *nxt
;
1346 blk_status_t ret
= BLK_STS_OK
;
1347 LIST_HEAD(zone_list
);
1349 if (list_empty(list
))
1353 * Now process all the entries, sending them to the driver.
1355 errors
= queued
= 0;
1357 struct blk_mq_queue_data bd
;
1359 rq
= list_first_entry(list
, struct request
, queuelist
);
1361 WARN_ON_ONCE(hctx
!= rq
->mq_hctx
);
1362 prep
= blk_mq_prep_dispatch_rq(rq
, !nr_budgets
);
1363 if (prep
!= PREP_DISPATCH_OK
)
1366 list_del_init(&rq
->queuelist
);
1371 * Flag last if we have no more requests, or if we have more
1372 * but can't assign a driver tag to it.
1374 if (list_empty(list
))
1377 nxt
= list_first_entry(list
, struct request
, queuelist
);
1378 bd
.last
= !blk_mq_get_driver_tag(nxt
);
1382 * once the request is queued to lld, no need to cover the
1387 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1392 case BLK_STS_RESOURCE
:
1393 case BLK_STS_DEV_RESOURCE
:
1394 blk_mq_handle_dev_resource(rq
, list
);
1396 case BLK_STS_ZONE_RESOURCE
:
1398 * Move the request to zone_list and keep going through
1399 * the dispatch list to find more requests the drive can
1402 blk_mq_handle_zone_resource(rq
, &zone_list
);
1406 blk_mq_end_request(rq
, BLK_STS_IOERR
);
1408 } while (!list_empty(list
));
1410 if (!list_empty(&zone_list
))
1411 list_splice_tail_init(&zone_list
, list
);
1413 hctx
->dispatched
[queued_to_index(queued
)]++;
1416 * Any items that need requeuing? Stuff them into hctx->dispatch,
1417 * that is where we will continue on next queue run.
1419 if (!list_empty(list
)) {
1421 /* For non-shared tags, the RESTART check will suffice */
1422 bool no_tag
= prep
== PREP_DISPATCH_NO_TAG
&&
1423 (hctx
->flags
& BLK_MQ_F_TAG_SHARED
);
1424 bool no_budget_avail
= prep
== PREP_DISPATCH_NO_BUDGET
;
1426 blk_mq_release_budgets(q
, nr_budgets
);
1429 * If we didn't flush the entire list, we could have told
1430 * the driver there was more coming, but that turned out to
1433 if (q
->mq_ops
->commit_rqs
&& queued
)
1434 q
->mq_ops
->commit_rqs(hctx
);
1436 spin_lock(&hctx
->lock
);
1437 list_splice_tail_init(list
, &hctx
->dispatch
);
1438 spin_unlock(&hctx
->lock
);
1441 * Order adding requests to hctx->dispatch and checking
1442 * SCHED_RESTART flag. The pair of this smp_mb() is the one
1443 * in blk_mq_sched_restart(). Avoid restart code path to
1444 * miss the new added requests to hctx->dispatch, meantime
1445 * SCHED_RESTART is observed here.
1450 * If SCHED_RESTART was set by the caller of this function and
1451 * it is no longer set that means that it was cleared by another
1452 * thread and hence that a queue rerun is needed.
1454 * If 'no_tag' is set, that means that we failed getting
1455 * a driver tag with an I/O scheduler attached. If our dispatch
1456 * waitqueue is no longer active, ensure that we run the queue
1457 * AFTER adding our entries back to the list.
1459 * If no I/O scheduler has been configured it is possible that
1460 * the hardware queue got stopped and restarted before requests
1461 * were pushed back onto the dispatch list. Rerun the queue to
1462 * avoid starvation. Notes:
1463 * - blk_mq_run_hw_queue() checks whether or not a queue has
1464 * been stopped before rerunning a queue.
1465 * - Some but not all block drivers stop a queue before
1466 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
1469 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
1470 * bit is set, run queue after a delay to avoid IO stalls
1471 * that could otherwise occur if the queue is idle. We'll do
1472 * similar if we couldn't get budget and SCHED_RESTART is set.
1474 needs_restart
= blk_mq_sched_needs_restart(hctx
);
1475 if (!needs_restart
||
1476 (no_tag
&& list_empty_careful(&hctx
->dispatch_wait
.entry
)))
1477 blk_mq_run_hw_queue(hctx
, true);
1478 else if (needs_restart
&& (ret
== BLK_STS_RESOURCE
||
1480 blk_mq_delay_run_hw_queue(hctx
, BLK_MQ_RESOURCE_DELAY
);
1482 blk_mq_update_dispatch_busy(hctx
, true);
1485 blk_mq_update_dispatch_busy(hctx
, false);
1487 return (queued
+ errors
) != 0;
1491 * __blk_mq_run_hw_queue - Run a hardware queue.
1492 * @hctx: Pointer to the hardware queue to run.
1494 * Send pending requests to the hardware.
1496 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1501 * We should be running this queue from one of the CPUs that
1504 * There are at least two related races now between setting
1505 * hctx->next_cpu from blk_mq_hctx_next_cpu() and running
1506 * __blk_mq_run_hw_queue():
1508 * - hctx->next_cpu is found offline in blk_mq_hctx_next_cpu(),
1509 * but later it becomes online, then this warning is harmless
1512 * - hctx->next_cpu is found online in blk_mq_hctx_next_cpu(),
1513 * but later it becomes offline, then the warning can't be
1514 * triggered, and we depend on blk-mq timeout handler to
1515 * handle dispatched requests to this hctx
1517 if (!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
) &&
1518 cpu_online(hctx
->next_cpu
)) {
1519 printk(KERN_WARNING
"run queue from wrong CPU %d, hctx %s\n",
1520 raw_smp_processor_id(),
1521 cpumask_empty(hctx
->cpumask
) ? "inactive": "active");
1526 * We can't run the queue inline with ints disabled. Ensure that
1527 * we catch bad users of this early.
1529 WARN_ON_ONCE(in_interrupt());
1531 might_sleep_if(hctx
->flags
& BLK_MQ_F_BLOCKING
);
1533 hctx_lock(hctx
, &srcu_idx
);
1534 blk_mq_sched_dispatch_requests(hctx
);
1535 hctx_unlock(hctx
, srcu_idx
);
1538 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx
*hctx
)
1540 int cpu
= cpumask_first_and(hctx
->cpumask
, cpu_online_mask
);
1542 if (cpu
>= nr_cpu_ids
)
1543 cpu
= cpumask_first(hctx
->cpumask
);
1548 * It'd be great if the workqueue API had a way to pass
1549 * in a mask and had some smarts for more clever placement.
1550 * For now we just round-robin here, switching for every
1551 * BLK_MQ_CPU_WORK_BATCH queued items.
1553 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
1556 int next_cpu
= hctx
->next_cpu
;
1558 if (hctx
->queue
->nr_hw_queues
== 1)
1559 return WORK_CPU_UNBOUND
;
1561 if (--hctx
->next_cpu_batch
<= 0) {
1563 next_cpu
= cpumask_next_and(next_cpu
, hctx
->cpumask
,
1565 if (next_cpu
>= nr_cpu_ids
)
1566 next_cpu
= blk_mq_first_mapped_cpu(hctx
);
1567 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1571 * Do unbound schedule if we can't find a online CPU for this hctx,
1572 * and it should only happen in the path of handling CPU DEAD.
1574 if (!cpu_online(next_cpu
)) {
1581 * Make sure to re-select CPU next time once after CPUs
1582 * in hctx->cpumask become online again.
1584 hctx
->next_cpu
= next_cpu
;
1585 hctx
->next_cpu_batch
= 1;
1586 return WORK_CPU_UNBOUND
;
1589 hctx
->next_cpu
= next_cpu
;
1594 * __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue.
1595 * @hctx: Pointer to the hardware queue to run.
1596 * @async: If we want to run the queue asynchronously.
1597 * @msecs: Microseconds of delay to wait before running the queue.
1599 * If !@async, try to run the queue now. Else, run the queue asynchronously and
1600 * with a delay of @msecs.
1602 static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
,
1603 unsigned long msecs
)
1605 if (unlikely(blk_mq_hctx_stopped(hctx
)))
1608 if (!async
&& !(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1609 int cpu
= get_cpu();
1610 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
1611 __blk_mq_run_hw_queue(hctx
);
1619 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx
), &hctx
->run_work
,
1620 msecs_to_jiffies(msecs
));
1624 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
1625 * @hctx: Pointer to the hardware queue to run.
1626 * @msecs: Microseconds of delay to wait before running the queue.
1628 * Run a hardware queue asynchronously with a delay of @msecs.
1630 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1632 __blk_mq_delay_run_hw_queue(hctx
, true, msecs
);
1634 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue
);
1637 * blk_mq_run_hw_queue - Start to run a hardware queue.
1638 * @hctx: Pointer to the hardware queue to run.
1639 * @async: If we want to run the queue asynchronously.
1641 * Check if the request queue is not in a quiesced state and if there are
1642 * pending requests to be sent. If this is true, run the queue to send requests
1645 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1651 * When queue is quiesced, we may be switching io scheduler, or
1652 * updating nr_hw_queues, or other things, and we can't run queue
1653 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
1655 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
1658 hctx_lock(hctx
, &srcu_idx
);
1659 need_run
= !blk_queue_quiesced(hctx
->queue
) &&
1660 blk_mq_hctx_has_pending(hctx
);
1661 hctx_unlock(hctx
, srcu_idx
);
1664 __blk_mq_delay_run_hw_queue(hctx
, async
, 0);
1666 EXPORT_SYMBOL(blk_mq_run_hw_queue
);
1669 * blk_mq_run_hw_queue - Run all hardware queues in a request queue.
1670 * @q: Pointer to the request queue to run.
1671 * @async: If we want to run the queue asynchronously.
1673 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
1675 struct blk_mq_hw_ctx
*hctx
;
1678 queue_for_each_hw_ctx(q
, hctx
, i
) {
1679 if (blk_mq_hctx_stopped(hctx
))
1682 blk_mq_run_hw_queue(hctx
, async
);
1685 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
1688 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
1689 * @q: Pointer to the request queue to run.
1690 * @msecs: Microseconds of delay to wait before running the queues.
1692 void blk_mq_delay_run_hw_queues(struct request_queue
*q
, unsigned long msecs
)
1694 struct blk_mq_hw_ctx
*hctx
;
1697 queue_for_each_hw_ctx(q
, hctx
, i
) {
1698 if (blk_mq_hctx_stopped(hctx
))
1701 blk_mq_delay_run_hw_queue(hctx
, msecs
);
1704 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues
);
1707 * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
1708 * @q: request queue.
1710 * The caller is responsible for serializing this function against
1711 * blk_mq_{start,stop}_hw_queue().
1713 bool blk_mq_queue_stopped(struct request_queue
*q
)
1715 struct blk_mq_hw_ctx
*hctx
;
1718 queue_for_each_hw_ctx(q
, hctx
, i
)
1719 if (blk_mq_hctx_stopped(hctx
))
1724 EXPORT_SYMBOL(blk_mq_queue_stopped
);
1727 * This function is often used for pausing .queue_rq() by driver when
1728 * there isn't enough resource or some conditions aren't satisfied, and
1729 * BLK_STS_RESOURCE is usually returned.
1731 * We do not guarantee that dispatch can be drained or blocked
1732 * after blk_mq_stop_hw_queue() returns. Please use
1733 * blk_mq_quiesce_queue() for that requirement.
1735 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1737 cancel_delayed_work(&hctx
->run_work
);
1739 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1741 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
1744 * This function is often used for pausing .queue_rq() by driver when
1745 * there isn't enough resource or some conditions aren't satisfied, and
1746 * BLK_STS_RESOURCE is usually returned.
1748 * We do not guarantee that dispatch can be drained or blocked
1749 * after blk_mq_stop_hw_queues() returns. Please use
1750 * blk_mq_quiesce_queue() for that requirement.
1752 void blk_mq_stop_hw_queues(struct request_queue
*q
)
1754 struct blk_mq_hw_ctx
*hctx
;
1757 queue_for_each_hw_ctx(q
, hctx
, i
)
1758 blk_mq_stop_hw_queue(hctx
);
1760 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
1762 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1764 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1766 blk_mq_run_hw_queue(hctx
, false);
1768 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
1770 void blk_mq_start_hw_queues(struct request_queue
*q
)
1772 struct blk_mq_hw_ctx
*hctx
;
1775 queue_for_each_hw_ctx(q
, hctx
, i
)
1776 blk_mq_start_hw_queue(hctx
);
1778 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
1780 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1782 if (!blk_mq_hctx_stopped(hctx
))
1785 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1786 blk_mq_run_hw_queue(hctx
, async
);
1788 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue
);
1790 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
1792 struct blk_mq_hw_ctx
*hctx
;
1795 queue_for_each_hw_ctx(q
, hctx
, i
)
1796 blk_mq_start_stopped_hw_queue(hctx
, async
);
1798 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
1800 static void blk_mq_run_work_fn(struct work_struct
*work
)
1802 struct blk_mq_hw_ctx
*hctx
;
1804 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
1807 * If we are stopped, don't run the queue.
1809 if (test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
1812 __blk_mq_run_hw_queue(hctx
);
1815 static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx
*hctx
,
1819 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1820 enum hctx_type type
= hctx
->type
;
1822 lockdep_assert_held(&ctx
->lock
);
1824 trace_block_rq_insert(hctx
->queue
, rq
);
1827 list_add(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
1829 list_add_tail(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
1832 void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
1835 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1837 lockdep_assert_held(&ctx
->lock
);
1839 __blk_mq_insert_req_list(hctx
, rq
, at_head
);
1840 blk_mq_hctx_mark_pending(hctx
, ctx
);
1844 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
1845 * @rq: Pointer to request to be inserted.
1846 * @at_head: true if the request should be inserted at the head of the list.
1847 * @run_queue: If we should run the hardware queue after inserting the request.
1849 * Should only be used carefully, when the caller knows we want to
1850 * bypass a potential IO scheduler on the target device.
1852 void blk_mq_request_bypass_insert(struct request
*rq
, bool at_head
,
1855 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
1857 spin_lock(&hctx
->lock
);
1859 list_add(&rq
->queuelist
, &hctx
->dispatch
);
1861 list_add_tail(&rq
->queuelist
, &hctx
->dispatch
);
1862 spin_unlock(&hctx
->lock
);
1865 blk_mq_run_hw_queue(hctx
, false);
1868 void blk_mq_insert_requests(struct blk_mq_hw_ctx
*hctx
, struct blk_mq_ctx
*ctx
,
1869 struct list_head
*list
)
1873 enum hctx_type type
= hctx
->type
;
1876 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1879 list_for_each_entry(rq
, list
, queuelist
) {
1880 BUG_ON(rq
->mq_ctx
!= ctx
);
1881 trace_block_rq_insert(hctx
->queue
, rq
);
1884 spin_lock(&ctx
->lock
);
1885 list_splice_tail_init(list
, &ctx
->rq_lists
[type
]);
1886 blk_mq_hctx_mark_pending(hctx
, ctx
);
1887 spin_unlock(&ctx
->lock
);
1890 static int plug_rq_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1892 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1893 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1895 if (rqa
->mq_ctx
!= rqb
->mq_ctx
)
1896 return rqa
->mq_ctx
> rqb
->mq_ctx
;
1897 if (rqa
->mq_hctx
!= rqb
->mq_hctx
)
1898 return rqa
->mq_hctx
> rqb
->mq_hctx
;
1900 return blk_rq_pos(rqa
) > blk_rq_pos(rqb
);
1903 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1907 if (list_empty(&plug
->mq_list
))
1909 list_splice_init(&plug
->mq_list
, &list
);
1911 if (plug
->rq_count
> 2 && plug
->multiple_queues
)
1912 list_sort(NULL
, &list
, plug_rq_cmp
);
1917 struct list_head rq_list
;
1918 struct request
*rq
, *head_rq
= list_entry_rq(list
.next
);
1919 struct list_head
*pos
= &head_rq
->queuelist
; /* skip first */
1920 struct blk_mq_hw_ctx
*this_hctx
= head_rq
->mq_hctx
;
1921 struct blk_mq_ctx
*this_ctx
= head_rq
->mq_ctx
;
1922 unsigned int depth
= 1;
1924 list_for_each_continue(pos
, &list
) {
1925 rq
= list_entry_rq(pos
);
1927 if (rq
->mq_hctx
!= this_hctx
|| rq
->mq_ctx
!= this_ctx
)
1932 list_cut_before(&rq_list
, &list
, pos
);
1933 trace_block_unplug(head_rq
->q
, depth
, !from_schedule
);
1934 blk_mq_sched_insert_requests(this_hctx
, this_ctx
, &rq_list
,
1936 } while(!list_empty(&list
));
1939 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
,
1940 unsigned int nr_segs
)
1942 if (bio
->bi_opf
& REQ_RAHEAD
)
1943 rq
->cmd_flags
|= REQ_FAILFAST_MASK
;
1945 rq
->__sector
= bio
->bi_iter
.bi_sector
;
1946 rq
->write_hint
= bio
->bi_write_hint
;
1947 blk_rq_bio_prep(rq
, bio
, nr_segs
);
1948 blk_crypto_rq_bio_prep(rq
, bio
, GFP_NOIO
);
1950 blk_account_io_start(rq
);
1953 static blk_status_t
__blk_mq_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1955 blk_qc_t
*cookie
, bool last
)
1957 struct request_queue
*q
= rq
->q
;
1958 struct blk_mq_queue_data bd
= {
1962 blk_qc_t new_cookie
;
1965 new_cookie
= request_to_qc_t(hctx
, rq
);
1968 * For OK queue, we are done. For error, caller may kill it.
1969 * Any other error (busy), just add it to our list as we
1970 * previously would have done.
1972 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1975 blk_mq_update_dispatch_busy(hctx
, false);
1976 *cookie
= new_cookie
;
1978 case BLK_STS_RESOURCE
:
1979 case BLK_STS_DEV_RESOURCE
:
1980 blk_mq_update_dispatch_busy(hctx
, true);
1981 __blk_mq_requeue_request(rq
);
1984 blk_mq_update_dispatch_busy(hctx
, false);
1985 *cookie
= BLK_QC_T_NONE
;
1992 static blk_status_t
__blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1995 bool bypass_insert
, bool last
)
1997 struct request_queue
*q
= rq
->q
;
1998 bool run_queue
= true;
2001 * RCU or SRCU read lock is needed before checking quiesced flag.
2003 * When queue is stopped or quiesced, ignore 'bypass_insert' from
2004 * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
2005 * and avoid driver to try to dispatch again.
2007 if (blk_mq_hctx_stopped(hctx
) || blk_queue_quiesced(q
)) {
2009 bypass_insert
= false;
2013 if (q
->elevator
&& !bypass_insert
)
2016 if (!blk_mq_get_dispatch_budget(q
))
2019 if (!blk_mq_get_driver_tag(rq
)) {
2020 blk_mq_put_dispatch_budget(q
);
2024 return __blk_mq_issue_directly(hctx
, rq
, cookie
, last
);
2027 return BLK_STS_RESOURCE
;
2029 blk_mq_request_bypass_insert(rq
, false, run_queue
);
2034 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2035 * @hctx: Pointer of the associated hardware queue.
2036 * @rq: Pointer to request to be sent.
2037 * @cookie: Request queue cookie.
2039 * If the device has enough resources to accept a new request now, send the
2040 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2041 * we can try send it another time in the future. Requests inserted at this
2042 * queue have higher priority.
2044 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
2045 struct request
*rq
, blk_qc_t
*cookie
)
2050 might_sleep_if(hctx
->flags
& BLK_MQ_F_BLOCKING
);
2052 hctx_lock(hctx
, &srcu_idx
);
2054 ret
= __blk_mq_try_issue_directly(hctx
, rq
, cookie
, false, true);
2055 if (ret
== BLK_STS_RESOURCE
|| ret
== BLK_STS_DEV_RESOURCE
)
2056 blk_mq_request_bypass_insert(rq
, false, true);
2057 else if (ret
!= BLK_STS_OK
)
2058 blk_mq_end_request(rq
, ret
);
2060 hctx_unlock(hctx
, srcu_idx
);
2063 blk_status_t
blk_mq_request_issue_directly(struct request
*rq
, bool last
)
2067 blk_qc_t unused_cookie
;
2068 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
2070 hctx_lock(hctx
, &srcu_idx
);
2071 ret
= __blk_mq_try_issue_directly(hctx
, rq
, &unused_cookie
, true, last
);
2072 hctx_unlock(hctx
, srcu_idx
);
2077 void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx
*hctx
,
2078 struct list_head
*list
)
2082 while (!list_empty(list
)) {
2084 struct request
*rq
= list_first_entry(list
, struct request
,
2087 list_del_init(&rq
->queuelist
);
2088 ret
= blk_mq_request_issue_directly(rq
, list_empty(list
));
2089 if (ret
!= BLK_STS_OK
) {
2090 if (ret
== BLK_STS_RESOURCE
||
2091 ret
== BLK_STS_DEV_RESOURCE
) {
2092 blk_mq_request_bypass_insert(rq
, false,
2096 blk_mq_end_request(rq
, ret
);
2102 * If we didn't flush the entire list, we could have told
2103 * the driver there was more coming, but that turned out to
2106 if (!list_empty(list
) && hctx
->queue
->mq_ops
->commit_rqs
&& queued
)
2107 hctx
->queue
->mq_ops
->commit_rqs(hctx
);
2110 static void blk_add_rq_to_plug(struct blk_plug
*plug
, struct request
*rq
)
2112 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
2114 if (!plug
->multiple_queues
&& !list_is_singular(&plug
->mq_list
)) {
2115 struct request
*tmp
;
2117 tmp
= list_first_entry(&plug
->mq_list
, struct request
,
2119 if (tmp
->q
!= rq
->q
)
2120 plug
->multiple_queues
= true;
2125 * blk_mq_submit_bio - Create and send a request to block device.
2126 * @bio: Bio pointer.
2128 * Builds up a request structure from @q and @bio and send to the device. The
2129 * request may not be queued directly to hardware if:
2130 * * This request can be merged with another one
2131 * * We want to place request at plug queue for possible future merging
2132 * * There is an IO scheduler active at this queue
2134 * It will not queue the request if there is an error with the bio, or at the
2137 * Returns: Request queue cookie.
2139 blk_qc_t
blk_mq_submit_bio(struct bio
*bio
)
2141 struct request_queue
*q
= bio
->bi_disk
->queue
;
2142 const int is_sync
= op_is_sync(bio
->bi_opf
);
2143 const int is_flush_fua
= op_is_flush(bio
->bi_opf
);
2144 struct blk_mq_alloc_data data
= {
2148 struct blk_plug
*plug
;
2149 struct request
*same_queue_rq
= NULL
;
2150 unsigned int nr_segs
;
2154 blk_queue_bounce(q
, &bio
);
2155 __blk_queue_split(&bio
, &nr_segs
);
2157 if (!bio_integrity_prep(bio
))
2160 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
2161 blk_attempt_plug_merge(q
, bio
, nr_segs
, &same_queue_rq
))
2164 if (blk_mq_sched_bio_merge(q
, bio
, nr_segs
))
2167 rq_qos_throttle(q
, bio
);
2169 data
.cmd_flags
= bio
->bi_opf
;
2170 rq
= __blk_mq_alloc_request(&data
);
2171 if (unlikely(!rq
)) {
2172 rq_qos_cleanup(q
, bio
);
2173 if (bio
->bi_opf
& REQ_NOWAIT
)
2174 bio_wouldblock_error(bio
);
2178 trace_block_getrq(q
, bio
, bio
->bi_opf
);
2180 rq_qos_track(q
, rq
, bio
);
2182 cookie
= request_to_qc_t(data
.hctx
, rq
);
2184 blk_mq_bio_to_request(rq
, bio
, nr_segs
);
2186 ret
= blk_crypto_init_request(rq
);
2187 if (ret
!= BLK_STS_OK
) {
2188 bio
->bi_status
= ret
;
2190 blk_mq_free_request(rq
);
2191 return BLK_QC_T_NONE
;
2194 plug
= blk_mq_plug(q
, bio
);
2195 if (unlikely(is_flush_fua
)) {
2196 /* Bypass scheduler for flush requests */
2197 blk_insert_flush(rq
);
2198 blk_mq_run_hw_queue(data
.hctx
, true);
2199 } else if (plug
&& (q
->nr_hw_queues
== 1 || q
->mq_ops
->commit_rqs
||
2200 !blk_queue_nonrot(q
))) {
2202 * Use plugging if we have a ->commit_rqs() hook as well, as
2203 * we know the driver uses bd->last in a smart fashion.
2205 * Use normal plugging if this disk is slow HDD, as sequential
2206 * IO may benefit a lot from plug merging.
2208 unsigned int request_count
= plug
->rq_count
;
2209 struct request
*last
= NULL
;
2212 trace_block_plug(q
);
2214 last
= list_entry_rq(plug
->mq_list
.prev
);
2216 if (request_count
>= BLK_MAX_REQUEST_COUNT
|| (last
&&
2217 blk_rq_bytes(last
) >= BLK_PLUG_FLUSH_SIZE
)) {
2218 blk_flush_plug_list(plug
, false);
2219 trace_block_plug(q
);
2222 blk_add_rq_to_plug(plug
, rq
);
2223 } else if (q
->elevator
) {
2224 /* Insert the request at the IO scheduler queue */
2225 blk_mq_sched_insert_request(rq
, false, true, true);
2226 } else if (plug
&& !blk_queue_nomerges(q
)) {
2228 * We do limited plugging. If the bio can be merged, do that.
2229 * Otherwise the existing request in the plug list will be
2230 * issued. So the plug list will have one request at most
2231 * The plug list might get flushed before this. If that happens,
2232 * the plug list is empty, and same_queue_rq is invalid.
2234 if (list_empty(&plug
->mq_list
))
2235 same_queue_rq
= NULL
;
2236 if (same_queue_rq
) {
2237 list_del_init(&same_queue_rq
->queuelist
);
2240 blk_add_rq_to_plug(plug
, rq
);
2241 trace_block_plug(q
);
2243 if (same_queue_rq
) {
2244 data
.hctx
= same_queue_rq
->mq_hctx
;
2245 trace_block_unplug(q
, 1, true);
2246 blk_mq_try_issue_directly(data
.hctx
, same_queue_rq
,
2249 } else if ((q
->nr_hw_queues
> 1 && is_sync
) ||
2250 !data
.hctx
->dispatch_busy
) {
2252 * There is no scheduler and we can try to send directly
2255 blk_mq_try_issue_directly(data
.hctx
, rq
, &cookie
);
2258 blk_mq_sched_insert_request(rq
, false, true, true);
2264 return BLK_QC_T_NONE
;
2266 EXPORT_SYMBOL_GPL(blk_mq_submit_bio
); /* only for request based dm */
2268 void blk_mq_free_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
2269 unsigned int hctx_idx
)
2273 if (tags
->rqs
&& set
->ops
->exit_request
) {
2276 for (i
= 0; i
< tags
->nr_tags
; i
++) {
2277 struct request
*rq
= tags
->static_rqs
[i
];
2281 set
->ops
->exit_request(set
, rq
, hctx_idx
);
2282 tags
->static_rqs
[i
] = NULL
;
2286 while (!list_empty(&tags
->page_list
)) {
2287 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
2288 list_del_init(&page
->lru
);
2290 * Remove kmemleak object previously allocated in
2291 * blk_mq_alloc_rqs().
2293 kmemleak_free(page_address(page
));
2294 __free_pages(page
, page
->private);
2298 void blk_mq_free_rq_map(struct blk_mq_tags
*tags
)
2302 kfree(tags
->static_rqs
);
2303 tags
->static_rqs
= NULL
;
2305 blk_mq_free_tags(tags
);
2308 struct blk_mq_tags
*blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
,
2309 unsigned int hctx_idx
,
2310 unsigned int nr_tags
,
2311 unsigned int reserved_tags
)
2313 struct blk_mq_tags
*tags
;
2316 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], hctx_idx
);
2317 if (node
== NUMA_NO_NODE
)
2318 node
= set
->numa_node
;
2320 tags
= blk_mq_init_tags(nr_tags
, reserved_tags
, node
,
2321 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
2325 tags
->rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
2326 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
2329 blk_mq_free_tags(tags
);
2333 tags
->static_rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
2334 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
2336 if (!tags
->static_rqs
) {
2338 blk_mq_free_tags(tags
);
2345 static size_t order_to_size(unsigned int order
)
2347 return (size_t)PAGE_SIZE
<< order
;
2350 static int blk_mq_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
2351 unsigned int hctx_idx
, int node
)
2355 if (set
->ops
->init_request
) {
2356 ret
= set
->ops
->init_request(set
, rq
, hctx_idx
, node
);
2361 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
2365 int blk_mq_alloc_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
2366 unsigned int hctx_idx
, unsigned int depth
)
2368 unsigned int i
, j
, entries_per_page
, max_order
= 4;
2369 size_t rq_size
, left
;
2372 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], hctx_idx
);
2373 if (node
== NUMA_NO_NODE
)
2374 node
= set
->numa_node
;
2376 INIT_LIST_HEAD(&tags
->page_list
);
2379 * rq_size is the size of the request plus driver payload, rounded
2380 * to the cacheline size
2382 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
2384 left
= rq_size
* depth
;
2386 for (i
= 0; i
< depth
; ) {
2387 int this_order
= max_order
;
2392 while (this_order
&& left
< order_to_size(this_order
- 1))
2396 page
= alloc_pages_node(node
,
2397 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
2403 if (order_to_size(this_order
) < rq_size
)
2410 page
->private = this_order
;
2411 list_add_tail(&page
->lru
, &tags
->page_list
);
2413 p
= page_address(page
);
2415 * Allow kmemleak to scan these pages as they contain pointers
2416 * to additional allocations like via ops->init_request().
2418 kmemleak_alloc(p
, order_to_size(this_order
), 1, GFP_NOIO
);
2419 entries_per_page
= order_to_size(this_order
) / rq_size
;
2420 to_do
= min(entries_per_page
, depth
- i
);
2421 left
-= to_do
* rq_size
;
2422 for (j
= 0; j
< to_do
; j
++) {
2423 struct request
*rq
= p
;
2425 tags
->static_rqs
[i
] = rq
;
2426 if (blk_mq_init_request(set
, rq
, hctx_idx
, node
)) {
2427 tags
->static_rqs
[i
] = NULL
;
2438 blk_mq_free_rqs(set
, tags
, hctx_idx
);
2442 struct rq_iter_data
{
2443 struct blk_mq_hw_ctx
*hctx
;
2447 static bool blk_mq_has_request(struct request
*rq
, void *data
, bool reserved
)
2449 struct rq_iter_data
*iter_data
= data
;
2451 if (rq
->mq_hctx
!= iter_data
->hctx
)
2453 iter_data
->has_rq
= true;
2457 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx
*hctx
)
2459 struct blk_mq_tags
*tags
= hctx
->sched_tags
?
2460 hctx
->sched_tags
: hctx
->tags
;
2461 struct rq_iter_data data
= {
2465 blk_mq_all_tag_iter(tags
, blk_mq_has_request
, &data
);
2469 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu
,
2470 struct blk_mq_hw_ctx
*hctx
)
2472 if (cpumask_next_and(-1, hctx
->cpumask
, cpu_online_mask
) != cpu
)
2474 if (cpumask_next_and(cpu
, hctx
->cpumask
, cpu_online_mask
) < nr_cpu_ids
)
2479 static int blk_mq_hctx_notify_offline(unsigned int cpu
, struct hlist_node
*node
)
2481 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
2482 struct blk_mq_hw_ctx
, cpuhp_online
);
2484 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
) ||
2485 !blk_mq_last_cpu_in_hctx(cpu
, hctx
))
2489 * Prevent new request from being allocated on the current hctx.
2491 * The smp_mb__after_atomic() Pairs with the implied barrier in
2492 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
2493 * seen once we return from the tag allocator.
2495 set_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
2496 smp_mb__after_atomic();
2499 * Try to grab a reference to the queue and wait for any outstanding
2500 * requests. If we could not grab a reference the queue has been
2501 * frozen and there are no requests.
2503 if (percpu_ref_tryget(&hctx
->queue
->q_usage_counter
)) {
2504 while (blk_mq_hctx_has_requests(hctx
))
2506 percpu_ref_put(&hctx
->queue
->q_usage_counter
);
2512 static int blk_mq_hctx_notify_online(unsigned int cpu
, struct hlist_node
*node
)
2514 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
2515 struct blk_mq_hw_ctx
, cpuhp_online
);
2517 if (cpumask_test_cpu(cpu
, hctx
->cpumask
))
2518 clear_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
2523 * 'cpu' is going away. splice any existing rq_list entries from this
2524 * software queue to the hw queue dispatch list, and ensure that it
2527 static int blk_mq_hctx_notify_dead(unsigned int cpu
, struct hlist_node
*node
)
2529 struct blk_mq_hw_ctx
*hctx
;
2530 struct blk_mq_ctx
*ctx
;
2532 enum hctx_type type
;
2534 hctx
= hlist_entry_safe(node
, struct blk_mq_hw_ctx
, cpuhp_dead
);
2535 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
))
2538 ctx
= __blk_mq_get_ctx(hctx
->queue
, cpu
);
2541 spin_lock(&ctx
->lock
);
2542 if (!list_empty(&ctx
->rq_lists
[type
])) {
2543 list_splice_init(&ctx
->rq_lists
[type
], &tmp
);
2544 blk_mq_hctx_clear_pending(hctx
, ctx
);
2546 spin_unlock(&ctx
->lock
);
2548 if (list_empty(&tmp
))
2551 spin_lock(&hctx
->lock
);
2552 list_splice_tail_init(&tmp
, &hctx
->dispatch
);
2553 spin_unlock(&hctx
->lock
);
2555 blk_mq_run_hw_queue(hctx
, true);
2559 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx
*hctx
)
2561 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
2562 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
2563 &hctx
->cpuhp_online
);
2564 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD
,
2568 /* hctx->ctxs will be freed in queue's release handler */
2569 static void blk_mq_exit_hctx(struct request_queue
*q
,
2570 struct blk_mq_tag_set
*set
,
2571 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
2573 if (blk_mq_hw_queue_mapped(hctx
))
2574 blk_mq_tag_idle(hctx
);
2576 if (set
->ops
->exit_request
)
2577 set
->ops
->exit_request(set
, hctx
->fq
->flush_rq
, hctx_idx
);
2579 if (set
->ops
->exit_hctx
)
2580 set
->ops
->exit_hctx(hctx
, hctx_idx
);
2582 blk_mq_remove_cpuhp(hctx
);
2584 spin_lock(&q
->unused_hctx_lock
);
2585 list_add(&hctx
->hctx_list
, &q
->unused_hctx_list
);
2586 spin_unlock(&q
->unused_hctx_lock
);
2589 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
2590 struct blk_mq_tag_set
*set
, int nr_queue
)
2592 struct blk_mq_hw_ctx
*hctx
;
2595 queue_for_each_hw_ctx(q
, hctx
, i
) {
2598 blk_mq_debugfs_unregister_hctx(hctx
);
2599 blk_mq_exit_hctx(q
, set
, hctx
, i
);
2603 static int blk_mq_hw_ctx_size(struct blk_mq_tag_set
*tag_set
)
2605 int hw_ctx_size
= sizeof(struct blk_mq_hw_ctx
);
2607 BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx
, srcu
),
2608 __alignof__(struct blk_mq_hw_ctx
)) !=
2609 sizeof(struct blk_mq_hw_ctx
));
2611 if (tag_set
->flags
& BLK_MQ_F_BLOCKING
)
2612 hw_ctx_size
+= sizeof(struct srcu_struct
);
2617 static int blk_mq_init_hctx(struct request_queue
*q
,
2618 struct blk_mq_tag_set
*set
,
2619 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
2621 hctx
->queue_num
= hctx_idx
;
2623 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
2624 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
2625 &hctx
->cpuhp_online
);
2626 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD
, &hctx
->cpuhp_dead
);
2628 hctx
->tags
= set
->tags
[hctx_idx
];
2630 if (set
->ops
->init_hctx
&&
2631 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
2632 goto unregister_cpu_notifier
;
2634 if (blk_mq_init_request(set
, hctx
->fq
->flush_rq
, hctx_idx
,
2640 if (set
->ops
->exit_hctx
)
2641 set
->ops
->exit_hctx(hctx
, hctx_idx
);
2642 unregister_cpu_notifier
:
2643 blk_mq_remove_cpuhp(hctx
);
2647 static struct blk_mq_hw_ctx
*
2648 blk_mq_alloc_hctx(struct request_queue
*q
, struct blk_mq_tag_set
*set
,
2651 struct blk_mq_hw_ctx
*hctx
;
2652 gfp_t gfp
= GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
;
2654 hctx
= kzalloc_node(blk_mq_hw_ctx_size(set
), gfp
, node
);
2656 goto fail_alloc_hctx
;
2658 if (!zalloc_cpumask_var_node(&hctx
->cpumask
, gfp
, node
))
2661 atomic_set(&hctx
->nr_active
, 0);
2662 if (node
== NUMA_NO_NODE
)
2663 node
= set
->numa_node
;
2664 hctx
->numa_node
= node
;
2666 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
2667 spin_lock_init(&hctx
->lock
);
2668 INIT_LIST_HEAD(&hctx
->dispatch
);
2670 hctx
->flags
= set
->flags
& ~BLK_MQ_F_TAG_SHARED
;
2672 INIT_LIST_HEAD(&hctx
->hctx_list
);
2675 * Allocate space for all possible cpus to avoid allocation at
2678 hctx
->ctxs
= kmalloc_array_node(nr_cpu_ids
, sizeof(void *),
2683 if (sbitmap_init_node(&hctx
->ctx_map
, nr_cpu_ids
, ilog2(8),
2688 spin_lock_init(&hctx
->dispatch_wait_lock
);
2689 init_waitqueue_func_entry(&hctx
->dispatch_wait
, blk_mq_dispatch_wake
);
2690 INIT_LIST_HEAD(&hctx
->dispatch_wait
.entry
);
2692 hctx
->fq
= blk_alloc_flush_queue(hctx
->numa_node
, set
->cmd_size
, gfp
);
2696 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
2697 init_srcu_struct(hctx
->srcu
);
2698 blk_mq_hctx_kobj_init(hctx
);
2703 sbitmap_free(&hctx
->ctx_map
);
2707 free_cpumask_var(hctx
->cpumask
);
2714 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
2715 unsigned int nr_hw_queues
)
2717 struct blk_mq_tag_set
*set
= q
->tag_set
;
2720 for_each_possible_cpu(i
) {
2721 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
2722 struct blk_mq_hw_ctx
*hctx
;
2726 spin_lock_init(&__ctx
->lock
);
2727 for (k
= HCTX_TYPE_DEFAULT
; k
< HCTX_MAX_TYPES
; k
++)
2728 INIT_LIST_HEAD(&__ctx
->rq_lists
[k
]);
2733 * Set local node, IFF we have more than one hw queue. If
2734 * not, we remain on the home node of the device
2736 for (j
= 0; j
< set
->nr_maps
; j
++) {
2737 hctx
= blk_mq_map_queue_type(q
, j
, i
);
2738 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
2739 hctx
->numa_node
= local_memory_node(cpu_to_node(i
));
2744 static bool __blk_mq_alloc_map_and_request(struct blk_mq_tag_set
*set
,
2749 set
->tags
[hctx_idx
] = blk_mq_alloc_rq_map(set
, hctx_idx
,
2750 set
->queue_depth
, set
->reserved_tags
);
2751 if (!set
->tags
[hctx_idx
])
2754 ret
= blk_mq_alloc_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
,
2759 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2760 set
->tags
[hctx_idx
] = NULL
;
2764 static void blk_mq_free_map_and_requests(struct blk_mq_tag_set
*set
,
2765 unsigned int hctx_idx
)
2767 if (set
->tags
&& set
->tags
[hctx_idx
]) {
2768 blk_mq_free_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
);
2769 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2770 set
->tags
[hctx_idx
] = NULL
;
2774 static void blk_mq_map_swqueue(struct request_queue
*q
)
2776 unsigned int i
, j
, hctx_idx
;
2777 struct blk_mq_hw_ctx
*hctx
;
2778 struct blk_mq_ctx
*ctx
;
2779 struct blk_mq_tag_set
*set
= q
->tag_set
;
2781 queue_for_each_hw_ctx(q
, hctx
, i
) {
2782 cpumask_clear(hctx
->cpumask
);
2784 hctx
->dispatch_from
= NULL
;
2788 * Map software to hardware queues.
2790 * If the cpu isn't present, the cpu is mapped to first hctx.
2792 for_each_possible_cpu(i
) {
2794 ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
2795 for (j
= 0; j
< set
->nr_maps
; j
++) {
2796 if (!set
->map
[j
].nr_queues
) {
2797 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
2798 HCTX_TYPE_DEFAULT
, i
);
2801 hctx_idx
= set
->map
[j
].mq_map
[i
];
2802 /* unmapped hw queue can be remapped after CPU topo changed */
2803 if (!set
->tags
[hctx_idx
] &&
2804 !__blk_mq_alloc_map_and_request(set
, hctx_idx
)) {
2806 * If tags initialization fail for some hctx,
2807 * that hctx won't be brought online. In this
2808 * case, remap the current ctx to hctx[0] which
2809 * is guaranteed to always have tags allocated
2811 set
->map
[j
].mq_map
[i
] = 0;
2814 hctx
= blk_mq_map_queue_type(q
, j
, i
);
2815 ctx
->hctxs
[j
] = hctx
;
2817 * If the CPU is already set in the mask, then we've
2818 * mapped this one already. This can happen if
2819 * devices share queues across queue maps.
2821 if (cpumask_test_cpu(i
, hctx
->cpumask
))
2824 cpumask_set_cpu(i
, hctx
->cpumask
);
2826 ctx
->index_hw
[hctx
->type
] = hctx
->nr_ctx
;
2827 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
2830 * If the nr_ctx type overflows, we have exceeded the
2831 * amount of sw queues we can support.
2833 BUG_ON(!hctx
->nr_ctx
);
2836 for (; j
< HCTX_MAX_TYPES
; j
++)
2837 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
2838 HCTX_TYPE_DEFAULT
, i
);
2841 queue_for_each_hw_ctx(q
, hctx
, i
) {
2843 * If no software queues are mapped to this hardware queue,
2844 * disable it and free the request entries.
2846 if (!hctx
->nr_ctx
) {
2847 /* Never unmap queue 0. We need it as a
2848 * fallback in case of a new remap fails
2851 if (i
&& set
->tags
[i
])
2852 blk_mq_free_map_and_requests(set
, i
);
2858 hctx
->tags
= set
->tags
[i
];
2859 WARN_ON(!hctx
->tags
);
2862 * Set the map size to the number of mapped software queues.
2863 * This is more accurate and more efficient than looping
2864 * over all possibly mapped software queues.
2866 sbitmap_resize(&hctx
->ctx_map
, hctx
->nr_ctx
);
2869 * Initialize batch roundrobin counts
2871 hctx
->next_cpu
= blk_mq_first_mapped_cpu(hctx
);
2872 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
2877 * Caller needs to ensure that we're either frozen/quiesced, or that
2878 * the queue isn't live yet.
2880 static void queue_set_hctx_shared(struct request_queue
*q
, bool shared
)
2882 struct blk_mq_hw_ctx
*hctx
;
2885 queue_for_each_hw_ctx(q
, hctx
, i
) {
2887 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
2889 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2893 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
,
2896 struct request_queue
*q
;
2898 lockdep_assert_held(&set
->tag_list_lock
);
2900 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
2901 blk_mq_freeze_queue(q
);
2902 queue_set_hctx_shared(q
, shared
);
2903 blk_mq_unfreeze_queue(q
);
2907 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
2909 struct blk_mq_tag_set
*set
= q
->tag_set
;
2911 mutex_lock(&set
->tag_list_lock
);
2912 list_del(&q
->tag_set_list
);
2913 if (list_is_singular(&set
->tag_list
)) {
2914 /* just transitioned to unshared */
2915 set
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2916 /* update existing queue */
2917 blk_mq_update_tag_set_depth(set
, false);
2919 mutex_unlock(&set
->tag_list_lock
);
2920 INIT_LIST_HEAD(&q
->tag_set_list
);
2923 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
2924 struct request_queue
*q
)
2926 mutex_lock(&set
->tag_list_lock
);
2929 * Check to see if we're transitioning to shared (from 1 to 2 queues).
2931 if (!list_empty(&set
->tag_list
) &&
2932 !(set
->flags
& BLK_MQ_F_TAG_SHARED
)) {
2933 set
->flags
|= BLK_MQ_F_TAG_SHARED
;
2934 /* update existing queue */
2935 blk_mq_update_tag_set_depth(set
, true);
2937 if (set
->flags
& BLK_MQ_F_TAG_SHARED
)
2938 queue_set_hctx_shared(q
, true);
2939 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
2941 mutex_unlock(&set
->tag_list_lock
);
2944 /* All allocations will be freed in release handler of q->mq_kobj */
2945 static int blk_mq_alloc_ctxs(struct request_queue
*q
)
2947 struct blk_mq_ctxs
*ctxs
;
2950 ctxs
= kzalloc(sizeof(*ctxs
), GFP_KERNEL
);
2954 ctxs
->queue_ctx
= alloc_percpu(struct blk_mq_ctx
);
2955 if (!ctxs
->queue_ctx
)
2958 for_each_possible_cpu(cpu
) {
2959 struct blk_mq_ctx
*ctx
= per_cpu_ptr(ctxs
->queue_ctx
, cpu
);
2963 q
->mq_kobj
= &ctxs
->kobj
;
2964 q
->queue_ctx
= ctxs
->queue_ctx
;
2973 * It is the actual release handler for mq, but we do it from
2974 * request queue's release handler for avoiding use-after-free
2975 * and headache because q->mq_kobj shouldn't have been introduced,
2976 * but we can't group ctx/kctx kobj without it.
2978 void blk_mq_release(struct request_queue
*q
)
2980 struct blk_mq_hw_ctx
*hctx
, *next
;
2983 queue_for_each_hw_ctx(q
, hctx
, i
)
2984 WARN_ON_ONCE(hctx
&& list_empty(&hctx
->hctx_list
));
2986 /* all hctx are in .unused_hctx_list now */
2987 list_for_each_entry_safe(hctx
, next
, &q
->unused_hctx_list
, hctx_list
) {
2988 list_del_init(&hctx
->hctx_list
);
2989 kobject_put(&hctx
->kobj
);
2992 kfree(q
->queue_hw_ctx
);
2995 * release .mq_kobj and sw queue's kobject now because
2996 * both share lifetime with request queue.
2998 blk_mq_sysfs_deinit(q
);
3001 struct request_queue
*blk_mq_init_queue_data(struct blk_mq_tag_set
*set
,
3004 struct request_queue
*uninit_q
, *q
;
3006 uninit_q
= blk_alloc_queue(set
->numa_node
);
3008 return ERR_PTR(-ENOMEM
);
3009 uninit_q
->queuedata
= queuedata
;
3012 * Initialize the queue without an elevator. device_add_disk() will do
3013 * the initialization.
3015 q
= blk_mq_init_allocated_queue(set
, uninit_q
, false);
3017 blk_cleanup_queue(uninit_q
);
3021 EXPORT_SYMBOL_GPL(blk_mq_init_queue_data
);
3023 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
3025 return blk_mq_init_queue_data(set
, NULL
);
3027 EXPORT_SYMBOL(blk_mq_init_queue
);
3030 * Helper for setting up a queue with mq ops, given queue depth, and
3031 * the passed in mq ops flags.
3033 struct request_queue
*blk_mq_init_sq_queue(struct blk_mq_tag_set
*set
,
3034 const struct blk_mq_ops
*ops
,
3035 unsigned int queue_depth
,
3036 unsigned int set_flags
)
3038 struct request_queue
*q
;
3041 memset(set
, 0, sizeof(*set
));
3043 set
->nr_hw_queues
= 1;
3045 set
->queue_depth
= queue_depth
;
3046 set
->numa_node
= NUMA_NO_NODE
;
3047 set
->flags
= set_flags
;
3049 ret
= blk_mq_alloc_tag_set(set
);
3051 return ERR_PTR(ret
);
3053 q
= blk_mq_init_queue(set
);
3055 blk_mq_free_tag_set(set
);
3061 EXPORT_SYMBOL(blk_mq_init_sq_queue
);
3063 static struct blk_mq_hw_ctx
*blk_mq_alloc_and_init_hctx(
3064 struct blk_mq_tag_set
*set
, struct request_queue
*q
,
3065 int hctx_idx
, int node
)
3067 struct blk_mq_hw_ctx
*hctx
= NULL
, *tmp
;
3069 /* reuse dead hctx first */
3070 spin_lock(&q
->unused_hctx_lock
);
3071 list_for_each_entry(tmp
, &q
->unused_hctx_list
, hctx_list
) {
3072 if (tmp
->numa_node
== node
) {
3078 list_del_init(&hctx
->hctx_list
);
3079 spin_unlock(&q
->unused_hctx_lock
);
3082 hctx
= blk_mq_alloc_hctx(q
, set
, node
);
3086 if (blk_mq_init_hctx(q
, set
, hctx
, hctx_idx
))
3092 kobject_put(&hctx
->kobj
);
3097 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set
*set
,
3098 struct request_queue
*q
)
3101 struct blk_mq_hw_ctx
**hctxs
= q
->queue_hw_ctx
;
3103 if (q
->nr_hw_queues
< set
->nr_hw_queues
) {
3104 struct blk_mq_hw_ctx
**new_hctxs
;
3106 new_hctxs
= kcalloc_node(set
->nr_hw_queues
,
3107 sizeof(*new_hctxs
), GFP_KERNEL
,
3112 memcpy(new_hctxs
, hctxs
, q
->nr_hw_queues
*
3114 q
->queue_hw_ctx
= new_hctxs
;
3119 /* protect against switching io scheduler */
3120 mutex_lock(&q
->sysfs_lock
);
3121 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
3123 struct blk_mq_hw_ctx
*hctx
;
3125 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], i
);
3127 * If the hw queue has been mapped to another numa node,
3128 * we need to realloc the hctx. If allocation fails, fallback
3129 * to use the previous one.
3131 if (hctxs
[i
] && (hctxs
[i
]->numa_node
== node
))
3134 hctx
= blk_mq_alloc_and_init_hctx(set
, q
, i
, node
);
3137 blk_mq_exit_hctx(q
, set
, hctxs
[i
], i
);
3141 pr_warn("Allocate new hctx on node %d fails,\
3142 fallback to previous one on node %d\n",
3143 node
, hctxs
[i
]->numa_node
);
3149 * Increasing nr_hw_queues fails. Free the newly allocated
3150 * hctxs and keep the previous q->nr_hw_queues.
3152 if (i
!= set
->nr_hw_queues
) {
3153 j
= q
->nr_hw_queues
;
3157 end
= q
->nr_hw_queues
;
3158 q
->nr_hw_queues
= set
->nr_hw_queues
;
3161 for (; j
< end
; j
++) {
3162 struct blk_mq_hw_ctx
*hctx
= hctxs
[j
];
3166 blk_mq_free_map_and_requests(set
, j
);
3167 blk_mq_exit_hctx(q
, set
, hctx
, j
);
3171 mutex_unlock(&q
->sysfs_lock
);
3174 struct request_queue
*blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
3175 struct request_queue
*q
,
3178 /* mark the queue as mq asap */
3179 q
->mq_ops
= set
->ops
;
3181 q
->poll_cb
= blk_stat_alloc_callback(blk_mq_poll_stats_fn
,
3182 blk_mq_poll_stats_bkt
,
3183 BLK_MQ_POLL_STATS_BKTS
, q
);
3187 if (blk_mq_alloc_ctxs(q
))
3190 /* init q->mq_kobj and sw queues' kobjects */
3191 blk_mq_sysfs_init(q
);
3193 INIT_LIST_HEAD(&q
->unused_hctx_list
);
3194 spin_lock_init(&q
->unused_hctx_lock
);
3196 blk_mq_realloc_hw_ctxs(set
, q
);
3197 if (!q
->nr_hw_queues
)
3200 INIT_WORK(&q
->timeout_work
, blk_mq_timeout_work
);
3201 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
3205 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
3206 if (set
->nr_maps
> HCTX_TYPE_POLL
&&
3207 set
->map
[HCTX_TYPE_POLL
].nr_queues
)
3208 blk_queue_flag_set(QUEUE_FLAG_POLL
, q
);
3210 q
->sg_reserved_size
= INT_MAX
;
3212 INIT_DELAYED_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
3213 INIT_LIST_HEAD(&q
->requeue_list
);
3214 spin_lock_init(&q
->requeue_lock
);
3216 q
->nr_requests
= set
->queue_depth
;
3219 * Default to classic polling
3221 q
->poll_nsec
= BLK_MQ_POLL_CLASSIC
;
3223 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
3224 blk_mq_add_queue_tag_set(set
, q
);
3225 blk_mq_map_swqueue(q
);
3228 elevator_init_mq(q
);
3233 kfree(q
->queue_hw_ctx
);
3234 q
->nr_hw_queues
= 0;
3235 blk_mq_sysfs_deinit(q
);
3237 blk_stat_free_callback(q
->poll_cb
);
3241 return ERR_PTR(-ENOMEM
);
3243 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
3245 /* tags can _not_ be used after returning from blk_mq_exit_queue */
3246 void blk_mq_exit_queue(struct request_queue
*q
)
3248 struct blk_mq_tag_set
*set
= q
->tag_set
;
3250 blk_mq_del_queue_tag_set(q
);
3251 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
3254 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
3258 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
3259 if (!__blk_mq_alloc_map_and_request(set
, i
))
3266 blk_mq_free_map_and_requests(set
, i
);
3272 * Allocate the request maps associated with this tag_set. Note that this
3273 * may reduce the depth asked for, if memory is tight. set->queue_depth
3274 * will be updated to reflect the allocated depth.
3276 static int blk_mq_alloc_map_and_requests(struct blk_mq_tag_set
*set
)
3281 depth
= set
->queue_depth
;
3283 err
= __blk_mq_alloc_rq_maps(set
);
3287 set
->queue_depth
>>= 1;
3288 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
3292 } while (set
->queue_depth
);
3294 if (!set
->queue_depth
|| err
) {
3295 pr_err("blk-mq: failed to allocate request map\n");
3299 if (depth
!= set
->queue_depth
)
3300 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
3301 depth
, set
->queue_depth
);
3306 static int blk_mq_update_queue_map(struct blk_mq_tag_set
*set
)
3309 * blk_mq_map_queues() and multiple .map_queues() implementations
3310 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
3311 * number of hardware queues.
3313 if (set
->nr_maps
== 1)
3314 set
->map
[HCTX_TYPE_DEFAULT
].nr_queues
= set
->nr_hw_queues
;
3316 if (set
->ops
->map_queues
&& !is_kdump_kernel()) {
3320 * transport .map_queues is usually done in the following
3323 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
3324 * mask = get_cpu_mask(queue)
3325 * for_each_cpu(cpu, mask)
3326 * set->map[x].mq_map[cpu] = queue;
3329 * When we need to remap, the table has to be cleared for
3330 * killing stale mapping since one CPU may not be mapped
3333 for (i
= 0; i
< set
->nr_maps
; i
++)
3334 blk_mq_clear_mq_map(&set
->map
[i
]);
3336 return set
->ops
->map_queues(set
);
3338 BUG_ON(set
->nr_maps
> 1);
3339 return blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
3343 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set
*set
,
3344 int cur_nr_hw_queues
, int new_nr_hw_queues
)
3346 struct blk_mq_tags
**new_tags
;
3348 if (cur_nr_hw_queues
>= new_nr_hw_queues
)
3351 new_tags
= kcalloc_node(new_nr_hw_queues
, sizeof(struct blk_mq_tags
*),
3352 GFP_KERNEL
, set
->numa_node
);
3357 memcpy(new_tags
, set
->tags
, cur_nr_hw_queues
*
3358 sizeof(*set
->tags
));
3360 set
->tags
= new_tags
;
3361 set
->nr_hw_queues
= new_nr_hw_queues
;
3367 * Alloc a tag set to be associated with one or more request queues.
3368 * May fail with EINVAL for various error conditions. May adjust the
3369 * requested depth down, if it's too large. In that case, the set
3370 * value will be stored in set->queue_depth.
3372 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
3376 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
3378 if (!set
->nr_hw_queues
)
3380 if (!set
->queue_depth
)
3382 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
3385 if (!set
->ops
->queue_rq
)
3388 if (!set
->ops
->get_budget
^ !set
->ops
->put_budget
)
3391 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
3392 pr_info("blk-mq: reduced tag depth to %u\n",
3394 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
3399 else if (set
->nr_maps
> HCTX_MAX_TYPES
)
3403 * If a crashdump is active, then we are potentially in a very
3404 * memory constrained environment. Limit us to 1 queue and
3405 * 64 tags to prevent using too much memory.
3407 if (is_kdump_kernel()) {
3408 set
->nr_hw_queues
= 1;
3410 set
->queue_depth
= min(64U, set
->queue_depth
);
3413 * There is no use for more h/w queues than cpus if we just have
3416 if (set
->nr_maps
== 1 && set
->nr_hw_queues
> nr_cpu_ids
)
3417 set
->nr_hw_queues
= nr_cpu_ids
;
3419 if (blk_mq_realloc_tag_set_tags(set
, 0, set
->nr_hw_queues
) < 0)
3423 for (i
= 0; i
< set
->nr_maps
; i
++) {
3424 set
->map
[i
].mq_map
= kcalloc_node(nr_cpu_ids
,
3425 sizeof(set
->map
[i
].mq_map
[0]),
3426 GFP_KERNEL
, set
->numa_node
);
3427 if (!set
->map
[i
].mq_map
)
3428 goto out_free_mq_map
;
3429 set
->map
[i
].nr_queues
= is_kdump_kernel() ? 1 : set
->nr_hw_queues
;
3432 ret
= blk_mq_update_queue_map(set
);
3434 goto out_free_mq_map
;
3436 ret
= blk_mq_alloc_map_and_requests(set
);
3438 goto out_free_mq_map
;
3440 mutex_init(&set
->tag_list_lock
);
3441 INIT_LIST_HEAD(&set
->tag_list
);
3446 for (i
= 0; i
< set
->nr_maps
; i
++) {
3447 kfree(set
->map
[i
].mq_map
);
3448 set
->map
[i
].mq_map
= NULL
;
3454 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
3456 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
3460 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
3461 blk_mq_free_map_and_requests(set
, i
);
3463 for (j
= 0; j
< set
->nr_maps
; j
++) {
3464 kfree(set
->map
[j
].mq_map
);
3465 set
->map
[j
].mq_map
= NULL
;
3471 EXPORT_SYMBOL(blk_mq_free_tag_set
);
3473 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
3475 struct blk_mq_tag_set
*set
= q
->tag_set
;
3476 struct blk_mq_hw_ctx
*hctx
;
3482 if (q
->nr_requests
== nr
)
3485 blk_mq_freeze_queue(q
);
3486 blk_mq_quiesce_queue(q
);
3489 queue_for_each_hw_ctx(q
, hctx
, i
) {
3493 * If we're using an MQ scheduler, just update the scheduler
3494 * queue depth. This is similar to what the old code would do.
3496 if (!hctx
->sched_tags
) {
3497 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->tags
, nr
,
3500 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->sched_tags
,
3505 if (q
->elevator
&& q
->elevator
->type
->ops
.depth_updated
)
3506 q
->elevator
->type
->ops
.depth_updated(hctx
);
3510 q
->nr_requests
= nr
;
3512 blk_mq_unquiesce_queue(q
);
3513 blk_mq_unfreeze_queue(q
);
3519 * request_queue and elevator_type pair.
3520 * It is just used by __blk_mq_update_nr_hw_queues to cache
3521 * the elevator_type associated with a request_queue.
3523 struct blk_mq_qe_pair
{
3524 struct list_head node
;
3525 struct request_queue
*q
;
3526 struct elevator_type
*type
;
3530 * Cache the elevator_type in qe pair list and switch the
3531 * io scheduler to 'none'
3533 static bool blk_mq_elv_switch_none(struct list_head
*head
,
3534 struct request_queue
*q
)
3536 struct blk_mq_qe_pair
*qe
;
3541 qe
= kmalloc(sizeof(*qe
), GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
);
3545 INIT_LIST_HEAD(&qe
->node
);
3547 qe
->type
= q
->elevator
->type
;
3548 list_add(&qe
->node
, head
);
3550 mutex_lock(&q
->sysfs_lock
);
3552 * After elevator_switch_mq, the previous elevator_queue will be
3553 * released by elevator_release. The reference of the io scheduler
3554 * module get by elevator_get will also be put. So we need to get
3555 * a reference of the io scheduler module here to prevent it to be
3558 __module_get(qe
->type
->elevator_owner
);
3559 elevator_switch_mq(q
, NULL
);
3560 mutex_unlock(&q
->sysfs_lock
);
3565 static void blk_mq_elv_switch_back(struct list_head
*head
,
3566 struct request_queue
*q
)
3568 struct blk_mq_qe_pair
*qe
;
3569 struct elevator_type
*t
= NULL
;
3571 list_for_each_entry(qe
, head
, node
)
3580 list_del(&qe
->node
);
3583 mutex_lock(&q
->sysfs_lock
);
3584 elevator_switch_mq(q
, t
);
3585 mutex_unlock(&q
->sysfs_lock
);
3588 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
,
3591 struct request_queue
*q
;
3593 int prev_nr_hw_queues
;
3595 lockdep_assert_held(&set
->tag_list_lock
);
3597 if (set
->nr_maps
== 1 && nr_hw_queues
> nr_cpu_ids
)
3598 nr_hw_queues
= nr_cpu_ids
;
3599 if (nr_hw_queues
< 1)
3601 if (set
->nr_maps
== 1 && nr_hw_queues
== set
->nr_hw_queues
)
3604 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3605 blk_mq_freeze_queue(q
);
3607 * Switch IO scheduler to 'none', cleaning up the data associated
3608 * with the previous scheduler. We will switch back once we are done
3609 * updating the new sw to hw queue mappings.
3611 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3612 if (!blk_mq_elv_switch_none(&head
, q
))
3615 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3616 blk_mq_debugfs_unregister_hctxs(q
);
3617 blk_mq_sysfs_unregister(q
);
3620 prev_nr_hw_queues
= set
->nr_hw_queues
;
3621 if (blk_mq_realloc_tag_set_tags(set
, set
->nr_hw_queues
, nr_hw_queues
) <
3625 set
->nr_hw_queues
= nr_hw_queues
;
3627 blk_mq_update_queue_map(set
);
3628 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3629 blk_mq_realloc_hw_ctxs(set
, q
);
3630 if (q
->nr_hw_queues
!= set
->nr_hw_queues
) {
3631 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
3632 nr_hw_queues
, prev_nr_hw_queues
);
3633 set
->nr_hw_queues
= prev_nr_hw_queues
;
3634 blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
3637 blk_mq_map_swqueue(q
);
3641 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3642 blk_mq_sysfs_register(q
);
3643 blk_mq_debugfs_register_hctxs(q
);
3647 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3648 blk_mq_elv_switch_back(&head
, q
);
3650 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3651 blk_mq_unfreeze_queue(q
);
3654 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
, int nr_hw_queues
)
3656 mutex_lock(&set
->tag_list_lock
);
3657 __blk_mq_update_nr_hw_queues(set
, nr_hw_queues
);
3658 mutex_unlock(&set
->tag_list_lock
);
3660 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues
);
3662 /* Enable polling stats and return whether they were already enabled. */
3663 static bool blk_poll_stats_enable(struct request_queue
*q
)
3665 if (test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
3666 blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS
, q
))
3668 blk_stat_add_callback(q
, q
->poll_cb
);
3672 static void blk_mq_poll_stats_start(struct request_queue
*q
)
3675 * We don't arm the callback if polling stats are not enabled or the
3676 * callback is already active.
3678 if (!test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
3679 blk_stat_is_active(q
->poll_cb
))
3682 blk_stat_activate_msecs(q
->poll_cb
, 100);
3685 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
)
3687 struct request_queue
*q
= cb
->data
;
3690 for (bucket
= 0; bucket
< BLK_MQ_POLL_STATS_BKTS
; bucket
++) {
3691 if (cb
->stat
[bucket
].nr_samples
)
3692 q
->poll_stat
[bucket
] = cb
->stat
[bucket
];
3696 static unsigned long blk_mq_poll_nsecs(struct request_queue
*q
,
3699 unsigned long ret
= 0;
3703 * If stats collection isn't on, don't sleep but turn it on for
3706 if (!blk_poll_stats_enable(q
))
3710 * As an optimistic guess, use half of the mean service time
3711 * for this type of request. We can (and should) make this smarter.
3712 * For instance, if the completion latencies are tight, we can
3713 * get closer than just half the mean. This is especially
3714 * important on devices where the completion latencies are longer
3715 * than ~10 usec. We do use the stats for the relevant IO size
3716 * if available which does lead to better estimates.
3718 bucket
= blk_mq_poll_stats_bkt(rq
);
3722 if (q
->poll_stat
[bucket
].nr_samples
)
3723 ret
= (q
->poll_stat
[bucket
].mean
+ 1) / 2;
3728 static bool blk_mq_poll_hybrid_sleep(struct request_queue
*q
,
3731 struct hrtimer_sleeper hs
;
3732 enum hrtimer_mode mode
;
3736 if (rq
->rq_flags
& RQF_MQ_POLL_SLEPT
)
3740 * If we get here, hybrid polling is enabled. Hence poll_nsec can be:
3742 * 0: use half of prev avg
3743 * >0: use this specific value
3745 if (q
->poll_nsec
> 0)
3746 nsecs
= q
->poll_nsec
;
3748 nsecs
= blk_mq_poll_nsecs(q
, rq
);
3753 rq
->rq_flags
|= RQF_MQ_POLL_SLEPT
;
3756 * This will be replaced with the stats tracking code, using
3757 * 'avg_completion_time / 2' as the pre-sleep target.
3761 mode
= HRTIMER_MODE_REL
;
3762 hrtimer_init_sleeper_on_stack(&hs
, CLOCK_MONOTONIC
, mode
);
3763 hrtimer_set_expires(&hs
.timer
, kt
);
3766 if (blk_mq_rq_state(rq
) == MQ_RQ_COMPLETE
)
3768 set_current_state(TASK_UNINTERRUPTIBLE
);
3769 hrtimer_sleeper_start_expires(&hs
, mode
);
3772 hrtimer_cancel(&hs
.timer
);
3773 mode
= HRTIMER_MODE_ABS
;
3774 } while (hs
.task
&& !signal_pending(current
));
3776 __set_current_state(TASK_RUNNING
);
3777 destroy_hrtimer_on_stack(&hs
.timer
);
3781 static bool blk_mq_poll_hybrid(struct request_queue
*q
,
3782 struct blk_mq_hw_ctx
*hctx
, blk_qc_t cookie
)
3786 if (q
->poll_nsec
== BLK_MQ_POLL_CLASSIC
)
3789 if (!blk_qc_t_is_internal(cookie
))
3790 rq
= blk_mq_tag_to_rq(hctx
->tags
, blk_qc_t_to_tag(cookie
));
3792 rq
= blk_mq_tag_to_rq(hctx
->sched_tags
, blk_qc_t_to_tag(cookie
));
3794 * With scheduling, if the request has completed, we'll
3795 * get a NULL return here, as we clear the sched tag when
3796 * that happens. The request still remains valid, like always,
3797 * so we should be safe with just the NULL check.
3803 return blk_mq_poll_hybrid_sleep(q
, rq
);
3807 * blk_poll - poll for IO completions
3809 * @cookie: cookie passed back at IO submission time
3810 * @spin: whether to spin for completions
3813 * Poll for completions on the passed in queue. Returns number of
3814 * completed entries found. If @spin is true, then blk_poll will continue
3815 * looping until at least one completion is found, unless the task is
3816 * otherwise marked running (or we need to reschedule).
3818 int blk_poll(struct request_queue
*q
, blk_qc_t cookie
, bool spin
)
3820 struct blk_mq_hw_ctx
*hctx
;
3823 if (!blk_qc_t_valid(cookie
) ||
3824 !test_bit(QUEUE_FLAG_POLL
, &q
->queue_flags
))
3828 blk_flush_plug_list(current
->plug
, false);
3830 hctx
= q
->queue_hw_ctx
[blk_qc_t_to_queue_num(cookie
)];
3833 * If we sleep, have the caller restart the poll loop to reset
3834 * the state. Like for the other success return cases, the
3835 * caller is responsible for checking if the IO completed. If
3836 * the IO isn't complete, we'll get called again and will go
3837 * straight to the busy poll loop.
3839 if (blk_mq_poll_hybrid(q
, hctx
, cookie
))
3842 hctx
->poll_considered
++;
3844 state
= current
->state
;
3848 hctx
->poll_invoked
++;
3850 ret
= q
->mq_ops
->poll(hctx
);
3852 hctx
->poll_success
++;
3853 __set_current_state(TASK_RUNNING
);
3857 if (signal_pending_state(state
, current
))
3858 __set_current_state(TASK_RUNNING
);
3860 if (current
->state
== TASK_RUNNING
)
3862 if (ret
< 0 || !spin
)
3865 } while (!need_resched());
3867 __set_current_state(TASK_RUNNING
);
3870 EXPORT_SYMBOL_GPL(blk_poll
);
3872 unsigned int blk_mq_rq_cpu(struct request
*rq
)
3874 return rq
->mq_ctx
->cpu
;
3876 EXPORT_SYMBOL(blk_mq_rq_cpu
);
3878 static int __init
blk_mq_init(void)
3882 for_each_possible_cpu(i
)
3883 INIT_LIST_HEAD(&per_cpu(blk_cpu_done
, i
));
3884 open_softirq(BLOCK_SOFTIRQ
, blk_done_softirq
);
3886 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD
,
3887 "block/softirq:dead", NULL
,
3888 blk_softirq_cpu_dead
);
3889 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD
, "block/mq:dead", NULL
,
3890 blk_mq_hctx_notify_dead
);
3891 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE
, "block/mq:online",
3892 blk_mq_hctx_notify_online
,
3893 blk_mq_hctx_notify_offline
);
3896 subsys_initcall(blk_mq_init
);