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 void blk_mq_poll_stats_start(struct request_queue
*q
);
45 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
);
47 static int blk_mq_poll_stats_bkt(const struct request
*rq
)
49 int ddir
, sectors
, bucket
;
51 ddir
= rq_data_dir(rq
);
52 sectors
= blk_rq_stats_sectors(rq
);
54 bucket
= ddir
+ 2 * ilog2(sectors
);
58 else if (bucket
>= BLK_MQ_POLL_STATS_BKTS
)
59 return ddir
+ BLK_MQ_POLL_STATS_BKTS
- 2;
65 * Check if any of the ctx, dispatch list or elevator
66 * have pending work in this hardware queue.
68 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
70 return !list_empty_careful(&hctx
->dispatch
) ||
71 sbitmap_any_bit_set(&hctx
->ctx_map
) ||
72 blk_mq_sched_has_work(hctx
);
76 * Mark this ctx as having pending work in this hardware queue
78 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
79 struct blk_mq_ctx
*ctx
)
81 const int bit
= ctx
->index_hw
[hctx
->type
];
83 if (!sbitmap_test_bit(&hctx
->ctx_map
, bit
))
84 sbitmap_set_bit(&hctx
->ctx_map
, bit
);
87 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
88 struct blk_mq_ctx
*ctx
)
90 const int bit
= ctx
->index_hw
[hctx
->type
];
92 sbitmap_clear_bit(&hctx
->ctx_map
, bit
);
96 struct hd_struct
*part
;
97 unsigned int inflight
[2];
100 static bool blk_mq_check_inflight(struct blk_mq_hw_ctx
*hctx
,
101 struct request
*rq
, void *priv
,
104 struct mq_inflight
*mi
= priv
;
106 if (rq
->part
== mi
->part
)
107 mi
->inflight
[rq_data_dir(rq
)]++;
112 unsigned int blk_mq_in_flight(struct request_queue
*q
, struct hd_struct
*part
)
114 struct mq_inflight mi
= { .part
= part
};
116 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
118 return mi
.inflight
[0] + mi
.inflight
[1];
121 void blk_mq_in_flight_rw(struct request_queue
*q
, struct hd_struct
*part
,
122 unsigned int inflight
[2])
124 struct mq_inflight mi
= { .part
= part
};
126 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
127 inflight
[0] = mi
.inflight
[0];
128 inflight
[1] = mi
.inflight
[1];
131 void blk_freeze_queue_start(struct request_queue
*q
)
133 mutex_lock(&q
->mq_freeze_lock
);
134 if (++q
->mq_freeze_depth
== 1) {
135 percpu_ref_kill(&q
->q_usage_counter
);
136 mutex_unlock(&q
->mq_freeze_lock
);
138 blk_mq_run_hw_queues(q
, false);
140 mutex_unlock(&q
->mq_freeze_lock
);
143 EXPORT_SYMBOL_GPL(blk_freeze_queue_start
);
145 void blk_mq_freeze_queue_wait(struct request_queue
*q
)
147 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->q_usage_counter
));
149 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait
);
151 int blk_mq_freeze_queue_wait_timeout(struct request_queue
*q
,
152 unsigned long timeout
)
154 return wait_event_timeout(q
->mq_freeze_wq
,
155 percpu_ref_is_zero(&q
->q_usage_counter
),
158 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout
);
161 * Guarantee no request is in use, so we can change any data structure of
162 * the queue afterward.
164 void blk_freeze_queue(struct request_queue
*q
)
167 * In the !blk_mq case we are only calling this to kill the
168 * q_usage_counter, otherwise this increases the freeze depth
169 * and waits for it to return to zero. For this reason there is
170 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
171 * exported to drivers as the only user for unfreeze is blk_mq.
173 blk_freeze_queue_start(q
);
174 blk_mq_freeze_queue_wait(q
);
177 void blk_mq_freeze_queue(struct request_queue
*q
)
180 * ...just an alias to keep freeze and unfreeze actions balanced
181 * in the blk_mq_* namespace
185 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
187 void blk_mq_unfreeze_queue(struct request_queue
*q
)
189 mutex_lock(&q
->mq_freeze_lock
);
190 q
->mq_freeze_depth
--;
191 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
192 if (!q
->mq_freeze_depth
) {
193 percpu_ref_resurrect(&q
->q_usage_counter
);
194 wake_up_all(&q
->mq_freeze_wq
);
196 mutex_unlock(&q
->mq_freeze_lock
);
198 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
201 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
202 * mpt3sas driver such that this function can be removed.
204 void blk_mq_quiesce_queue_nowait(struct request_queue
*q
)
206 blk_queue_flag_set(QUEUE_FLAG_QUIESCED
, q
);
208 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait
);
211 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
214 * Note: this function does not prevent that the struct request end_io()
215 * callback function is invoked. Once this function is returned, we make
216 * sure no dispatch can happen until the queue is unquiesced via
217 * blk_mq_unquiesce_queue().
219 void blk_mq_quiesce_queue(struct request_queue
*q
)
221 struct blk_mq_hw_ctx
*hctx
;
225 blk_mq_quiesce_queue_nowait(q
);
227 queue_for_each_hw_ctx(q
, hctx
, i
) {
228 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
229 synchronize_srcu(hctx
->srcu
);
236 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue
);
239 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
242 * This function recovers queue into the state before quiescing
243 * which is done by blk_mq_quiesce_queue.
245 void blk_mq_unquiesce_queue(struct request_queue
*q
)
247 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED
, q
);
249 /* dispatch requests which are inserted during quiescing */
250 blk_mq_run_hw_queues(q
, true);
252 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue
);
254 void blk_mq_wake_waiters(struct request_queue
*q
)
256 struct blk_mq_hw_ctx
*hctx
;
259 queue_for_each_hw_ctx(q
, hctx
, i
)
260 if (blk_mq_hw_queue_mapped(hctx
))
261 blk_mq_tag_wakeup_all(hctx
->tags
, true);
265 * Only need start/end time stamping if we have iostat or
266 * blk stats enabled, or using an IO scheduler.
268 static inline bool blk_mq_need_time_stamp(struct request
*rq
)
270 return (rq
->rq_flags
& (RQF_IO_STAT
| RQF_STATS
)) || rq
->q
->elevator
;
273 static struct request
*blk_mq_rq_ctx_init(struct blk_mq_alloc_data
*data
,
274 unsigned int tag
, u64 alloc_time_ns
)
276 struct blk_mq_tags
*tags
= blk_mq_tags_from_data(data
);
277 struct request
*rq
= tags
->static_rqs
[tag
];
278 req_flags_t rq_flags
= 0;
280 if (data
->flags
& BLK_MQ_REQ_INTERNAL
) {
281 rq
->tag
= BLK_MQ_NO_TAG
;
282 rq
->internal_tag
= tag
;
284 if (data
->hctx
->flags
& BLK_MQ_F_TAG_SHARED
) {
285 rq_flags
= RQF_MQ_INFLIGHT
;
286 atomic_inc(&data
->hctx
->nr_active
);
289 rq
->internal_tag
= BLK_MQ_NO_TAG
;
290 data
->hctx
->tags
->rqs
[rq
->tag
] = rq
;
293 /* csd/requeue_work/fifo_time is initialized before use */
295 rq
->mq_ctx
= data
->ctx
;
296 rq
->mq_hctx
= data
->hctx
;
297 rq
->rq_flags
= rq_flags
;
298 rq
->cmd_flags
= data
->cmd_flags
;
299 if (data
->flags
& BLK_MQ_REQ_PREEMPT
)
300 rq
->rq_flags
|= RQF_PREEMPT
;
301 if (blk_queue_io_stat(data
->q
))
302 rq
->rq_flags
|= RQF_IO_STAT
;
303 INIT_LIST_HEAD(&rq
->queuelist
);
304 INIT_HLIST_NODE(&rq
->hash
);
305 RB_CLEAR_NODE(&rq
->rb_node
);
308 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
309 rq
->alloc_time_ns
= alloc_time_ns
;
311 if (blk_mq_need_time_stamp(rq
))
312 rq
->start_time_ns
= ktime_get_ns();
314 rq
->start_time_ns
= 0;
315 rq
->io_start_time_ns
= 0;
316 rq
->stats_sectors
= 0;
317 rq
->nr_phys_segments
= 0;
318 #if defined(CONFIG_BLK_DEV_INTEGRITY)
319 rq
->nr_integrity_segments
= 0;
321 blk_crypto_rq_set_defaults(rq
);
322 /* tag was already set */
323 WRITE_ONCE(rq
->deadline
, 0);
328 rq
->end_io_data
= NULL
;
330 data
->ctx
->rq_dispatched
[op_is_sync(data
->cmd_flags
)]++;
331 refcount_set(&rq
->ref
, 1);
333 if (!op_is_flush(data
->cmd_flags
)) {
334 struct elevator_queue
*e
= data
->q
->elevator
;
337 if (e
&& e
->type
->ops
.prepare_request
) {
338 if (e
->type
->icq_cache
)
339 blk_mq_sched_assign_ioc(rq
);
341 e
->type
->ops
.prepare_request(rq
);
342 rq
->rq_flags
|= RQF_ELVPRIV
;
346 data
->hctx
->queued
++;
350 static struct request
*__blk_mq_alloc_request(struct blk_mq_alloc_data
*data
)
352 struct request_queue
*q
= data
->q
;
353 struct elevator_queue
*e
= q
->elevator
;
354 u64 alloc_time_ns
= 0;
357 /* alloc_time includes depth and tag waits */
358 if (blk_queue_rq_alloc_time(q
))
359 alloc_time_ns
= ktime_get_ns();
361 if (data
->cmd_flags
& REQ_NOWAIT
)
362 data
->flags
|= BLK_MQ_REQ_NOWAIT
;
365 data
->flags
|= BLK_MQ_REQ_INTERNAL
;
368 * Flush requests are special and go directly to the
369 * dispatch list. Don't include reserved tags in the
370 * limiting, as it isn't useful.
372 if (!op_is_flush(data
->cmd_flags
) &&
373 e
->type
->ops
.limit_depth
&&
374 !(data
->flags
& BLK_MQ_REQ_RESERVED
))
375 e
->type
->ops
.limit_depth(data
->cmd_flags
, data
);
379 data
->ctx
= blk_mq_get_ctx(q
);
380 data
->hctx
= blk_mq_map_queue(q
, data
->cmd_flags
, data
->ctx
);
381 if (!(data
->flags
& BLK_MQ_REQ_INTERNAL
))
382 blk_mq_tag_busy(data
->hctx
);
385 * Waiting allocations only fail because of an inactive hctx. In that
386 * case just retry the hctx assignment and tag allocation as CPU hotplug
387 * should have migrated us to an online CPU by now.
389 tag
= blk_mq_get_tag(data
);
390 if (tag
== BLK_MQ_NO_TAG
) {
391 if (data
->flags
& BLK_MQ_REQ_NOWAIT
)
395 * Give up the CPU and sleep for a random short time to ensure
396 * that thread using a realtime scheduling class are migrated
397 * off the the CPU, and thus off the hctx that is going away.
402 return blk_mq_rq_ctx_init(data
, tag
, alloc_time_ns
);
405 struct request
*blk_mq_alloc_request(struct request_queue
*q
, unsigned int op
,
406 blk_mq_req_flags_t flags
)
408 struct blk_mq_alloc_data data
= {
416 ret
= blk_queue_enter(q
, flags
);
420 rq
= __blk_mq_alloc_request(&data
);
424 rq
->__sector
= (sector_t
) -1;
425 rq
->bio
= rq
->biotail
= NULL
;
429 return ERR_PTR(-EWOULDBLOCK
);
431 EXPORT_SYMBOL(blk_mq_alloc_request
);
433 struct request
*blk_mq_alloc_request_hctx(struct request_queue
*q
,
434 unsigned int op
, blk_mq_req_flags_t flags
, unsigned int hctx_idx
)
436 struct blk_mq_alloc_data data
= {
441 u64 alloc_time_ns
= 0;
446 /* alloc_time includes depth and tag waits */
447 if (blk_queue_rq_alloc_time(q
))
448 alloc_time_ns
= ktime_get_ns();
451 * If the tag allocator sleeps we could get an allocation for a
452 * different hardware context. No need to complicate the low level
453 * allocator for this for the rare use case of a command tied to
456 if (WARN_ON_ONCE(!(flags
& (BLK_MQ_REQ_NOWAIT
| BLK_MQ_REQ_RESERVED
))))
457 return ERR_PTR(-EINVAL
);
459 if (hctx_idx
>= q
->nr_hw_queues
)
460 return ERR_PTR(-EIO
);
462 ret
= blk_queue_enter(q
, flags
);
467 * Check if the hardware context is actually mapped to anything.
468 * If not tell the caller that it should skip this queue.
471 data
.hctx
= q
->queue_hw_ctx
[hctx_idx
];
472 if (!blk_mq_hw_queue_mapped(data
.hctx
))
474 cpu
= cpumask_first_and(data
.hctx
->cpumask
, cpu_online_mask
);
475 data
.ctx
= __blk_mq_get_ctx(q
, cpu
);
478 data
.flags
|= BLK_MQ_REQ_INTERNAL
;
480 blk_mq_tag_busy(data
.hctx
);
483 tag
= blk_mq_get_tag(&data
);
484 if (tag
== BLK_MQ_NO_TAG
)
486 return blk_mq_rq_ctx_init(&data
, tag
, alloc_time_ns
);
492 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx
);
494 static void __blk_mq_free_request(struct request
*rq
)
496 struct request_queue
*q
= rq
->q
;
497 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
498 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
499 const int sched_tag
= rq
->internal_tag
;
501 blk_crypto_free_request(rq
);
502 blk_pm_mark_last_busy(rq
);
504 if (rq
->tag
!= BLK_MQ_NO_TAG
)
505 blk_mq_put_tag(hctx
->tags
, ctx
, rq
->tag
);
506 if (sched_tag
!= BLK_MQ_NO_TAG
)
507 blk_mq_put_tag(hctx
->sched_tags
, ctx
, sched_tag
);
508 blk_mq_sched_restart(hctx
);
512 void blk_mq_free_request(struct request
*rq
)
514 struct request_queue
*q
= rq
->q
;
515 struct elevator_queue
*e
= q
->elevator
;
516 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
517 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
519 if (rq
->rq_flags
& RQF_ELVPRIV
) {
520 if (e
&& e
->type
->ops
.finish_request
)
521 e
->type
->ops
.finish_request(rq
);
523 put_io_context(rq
->elv
.icq
->ioc
);
528 ctx
->rq_completed
[rq_is_sync(rq
)]++;
529 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
)
530 atomic_dec(&hctx
->nr_active
);
532 if (unlikely(laptop_mode
&& !blk_rq_is_passthrough(rq
)))
533 laptop_io_completion(q
->backing_dev_info
);
537 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
538 if (refcount_dec_and_test(&rq
->ref
))
539 __blk_mq_free_request(rq
);
541 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
543 inline void __blk_mq_end_request(struct request
*rq
, blk_status_t error
)
547 if (blk_mq_need_time_stamp(rq
))
548 now
= ktime_get_ns();
550 if (rq
->rq_flags
& RQF_STATS
) {
551 blk_mq_poll_stats_start(rq
->q
);
552 blk_stat_add(rq
, now
);
555 if (rq
->internal_tag
!= BLK_MQ_NO_TAG
)
556 blk_mq_sched_completed_request(rq
, now
);
558 blk_account_io_done(rq
, now
);
561 rq_qos_done(rq
->q
, rq
);
562 rq
->end_io(rq
, error
);
564 blk_mq_free_request(rq
);
567 EXPORT_SYMBOL(__blk_mq_end_request
);
569 void blk_mq_end_request(struct request
*rq
, blk_status_t error
)
571 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
573 __blk_mq_end_request(rq
, error
);
575 EXPORT_SYMBOL(blk_mq_end_request
);
577 static void __blk_mq_complete_request_remote(void *data
)
579 struct request
*rq
= data
;
580 struct request_queue
*q
= rq
->q
;
582 q
->mq_ops
->complete(rq
);
586 * blk_mq_force_complete_rq() - Force complete the request, bypassing any error
587 * injection that could drop the completion.
588 * @rq: Request to be force completed
590 * Drivers should use blk_mq_complete_request() to complete requests in their
591 * normal IO path. For timeout error recovery, drivers may call this forced
592 * completion routine after they've reclaimed timed out requests to bypass
593 * potentially subsequent fake timeouts.
595 void blk_mq_force_complete_rq(struct request
*rq
)
597 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
598 struct request_queue
*q
= rq
->q
;
602 WRITE_ONCE(rq
->state
, MQ_RQ_COMPLETE
);
604 * Most of single queue controllers, there is only one irq vector
605 * for handling IO completion, and the only irq's affinity is set
606 * as all possible CPUs. On most of ARCHs, this affinity means the
607 * irq is handled on one specific CPU.
609 * So complete IO reqeust in softirq context in case of single queue
610 * for not degrading IO performance by irqsoff latency.
612 if (q
->nr_hw_queues
== 1) {
613 __blk_complete_request(rq
);
618 * For a polled request, always complete locallly, it's pointless
619 * to redirect the completion.
621 if ((rq
->cmd_flags
& REQ_HIPRI
) ||
622 !test_bit(QUEUE_FLAG_SAME_COMP
, &q
->queue_flags
)) {
623 q
->mq_ops
->complete(rq
);
628 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &q
->queue_flags
))
629 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
631 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
632 rq
->csd
.func
= __blk_mq_complete_request_remote
;
635 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
637 q
->mq_ops
->complete(rq
);
641 EXPORT_SYMBOL_GPL(blk_mq_force_complete_rq
);
643 static void hctx_unlock(struct blk_mq_hw_ctx
*hctx
, int srcu_idx
)
644 __releases(hctx
->srcu
)
646 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
))
649 srcu_read_unlock(hctx
->srcu
, srcu_idx
);
652 static void hctx_lock(struct blk_mq_hw_ctx
*hctx
, int *srcu_idx
)
653 __acquires(hctx
->srcu
)
655 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
656 /* shut up gcc false positive */
660 *srcu_idx
= srcu_read_lock(hctx
->srcu
);
664 * blk_mq_complete_request - end I/O on a request
665 * @rq: the request being processed
668 * Ends all I/O on a request. It does not handle partial completions.
669 * The actual completion happens out-of-order, through a IPI handler.
671 bool blk_mq_complete_request(struct request
*rq
)
673 if (unlikely(blk_should_fake_timeout(rq
->q
)))
675 blk_mq_force_complete_rq(rq
);
678 EXPORT_SYMBOL(blk_mq_complete_request
);
681 * blk_mq_start_request - Start processing a request
682 * @rq: Pointer to request to be started
684 * Function used by device drivers to notify the block layer that a request
685 * is going to be processed now, so blk layer can do proper initializations
686 * such as starting the timeout timer.
688 void blk_mq_start_request(struct request
*rq
)
690 struct request_queue
*q
= rq
->q
;
692 trace_block_rq_issue(q
, rq
);
694 if (test_bit(QUEUE_FLAG_STATS
, &q
->queue_flags
)) {
695 rq
->io_start_time_ns
= ktime_get_ns();
696 rq
->stats_sectors
= blk_rq_sectors(rq
);
697 rq
->rq_flags
|= RQF_STATS
;
701 WARN_ON_ONCE(blk_mq_rq_state(rq
) != MQ_RQ_IDLE
);
704 WRITE_ONCE(rq
->state
, MQ_RQ_IN_FLIGHT
);
706 #ifdef CONFIG_BLK_DEV_INTEGRITY
707 if (blk_integrity_rq(rq
) && req_op(rq
) == REQ_OP_WRITE
)
708 q
->integrity
.profile
->prepare_fn(rq
);
711 EXPORT_SYMBOL(blk_mq_start_request
);
713 static void __blk_mq_requeue_request(struct request
*rq
)
715 struct request_queue
*q
= rq
->q
;
717 blk_mq_put_driver_tag(rq
);
719 trace_block_rq_requeue(q
, rq
);
720 rq_qos_requeue(q
, rq
);
722 if (blk_mq_request_started(rq
)) {
723 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
724 rq
->rq_flags
&= ~RQF_TIMED_OUT
;
728 void blk_mq_requeue_request(struct request
*rq
, bool kick_requeue_list
)
730 __blk_mq_requeue_request(rq
);
732 /* this request will be re-inserted to io scheduler queue */
733 blk_mq_sched_requeue_request(rq
);
735 BUG_ON(!list_empty(&rq
->queuelist
));
736 blk_mq_add_to_requeue_list(rq
, true, kick_requeue_list
);
738 EXPORT_SYMBOL(blk_mq_requeue_request
);
740 static void blk_mq_requeue_work(struct work_struct
*work
)
742 struct request_queue
*q
=
743 container_of(work
, struct request_queue
, requeue_work
.work
);
745 struct request
*rq
, *next
;
747 spin_lock_irq(&q
->requeue_lock
);
748 list_splice_init(&q
->requeue_list
, &rq_list
);
749 spin_unlock_irq(&q
->requeue_lock
);
751 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
752 if (!(rq
->rq_flags
& (RQF_SOFTBARRIER
| RQF_DONTPREP
)))
755 rq
->rq_flags
&= ~RQF_SOFTBARRIER
;
756 list_del_init(&rq
->queuelist
);
758 * If RQF_DONTPREP, rq has contained some driver specific
759 * data, so insert it to hctx dispatch list to avoid any
762 if (rq
->rq_flags
& RQF_DONTPREP
)
763 blk_mq_request_bypass_insert(rq
, false, false);
765 blk_mq_sched_insert_request(rq
, true, false, false);
768 while (!list_empty(&rq_list
)) {
769 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
770 list_del_init(&rq
->queuelist
);
771 blk_mq_sched_insert_request(rq
, false, false, false);
774 blk_mq_run_hw_queues(q
, false);
777 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
,
778 bool kick_requeue_list
)
780 struct request_queue
*q
= rq
->q
;
784 * We abuse this flag that is otherwise used by the I/O scheduler to
785 * request head insertion from the workqueue.
787 BUG_ON(rq
->rq_flags
& RQF_SOFTBARRIER
);
789 spin_lock_irqsave(&q
->requeue_lock
, flags
);
791 rq
->rq_flags
|= RQF_SOFTBARRIER
;
792 list_add(&rq
->queuelist
, &q
->requeue_list
);
794 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
796 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
798 if (kick_requeue_list
)
799 blk_mq_kick_requeue_list(q
);
802 void blk_mq_kick_requeue_list(struct request_queue
*q
)
804 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
, 0);
806 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
808 void blk_mq_delay_kick_requeue_list(struct request_queue
*q
,
811 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
,
812 msecs_to_jiffies(msecs
));
814 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list
);
816 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
818 if (tag
< tags
->nr_tags
) {
819 prefetch(tags
->rqs
[tag
]);
820 return tags
->rqs
[tag
];
825 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
827 static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
828 void *priv
, bool reserved
)
831 * If we find a request that is inflight and the queue matches,
832 * we know the queue is busy. Return false to stop the iteration.
834 if (rq
->state
== MQ_RQ_IN_FLIGHT
&& rq
->q
== hctx
->queue
) {
844 bool blk_mq_queue_inflight(struct request_queue
*q
)
848 blk_mq_queue_tag_busy_iter(q
, blk_mq_rq_inflight
, &busy
);
851 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight
);
853 static void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
855 req
->rq_flags
|= RQF_TIMED_OUT
;
856 if (req
->q
->mq_ops
->timeout
) {
857 enum blk_eh_timer_return ret
;
859 ret
= req
->q
->mq_ops
->timeout(req
, reserved
);
860 if (ret
== BLK_EH_DONE
)
862 WARN_ON_ONCE(ret
!= BLK_EH_RESET_TIMER
);
868 static bool blk_mq_req_expired(struct request
*rq
, unsigned long *next
)
870 unsigned long deadline
;
872 if (blk_mq_rq_state(rq
) != MQ_RQ_IN_FLIGHT
)
874 if (rq
->rq_flags
& RQF_TIMED_OUT
)
877 deadline
= READ_ONCE(rq
->deadline
);
878 if (time_after_eq(jiffies
, deadline
))
883 else if (time_after(*next
, deadline
))
888 static bool blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
889 struct request
*rq
, void *priv
, bool reserved
)
891 unsigned long *next
= priv
;
894 * Just do a quick check if it is expired before locking the request in
895 * so we're not unnecessarilly synchronizing across CPUs.
897 if (!blk_mq_req_expired(rq
, next
))
901 * We have reason to believe the request may be expired. Take a
902 * reference on the request to lock this request lifetime into its
903 * currently allocated context to prevent it from being reallocated in
904 * the event the completion by-passes this timeout handler.
906 * If the reference was already released, then the driver beat the
907 * timeout handler to posting a natural completion.
909 if (!refcount_inc_not_zero(&rq
->ref
))
913 * The request is now locked and cannot be reallocated underneath the
914 * timeout handler's processing. Re-verify this exact request is truly
915 * expired; if it is not expired, then the request was completed and
916 * reallocated as a new request.
918 if (blk_mq_req_expired(rq
, next
))
919 blk_mq_rq_timed_out(rq
, reserved
);
921 if (is_flush_rq(rq
, hctx
))
923 else if (refcount_dec_and_test(&rq
->ref
))
924 __blk_mq_free_request(rq
);
929 static void blk_mq_timeout_work(struct work_struct
*work
)
931 struct request_queue
*q
=
932 container_of(work
, struct request_queue
, timeout_work
);
933 unsigned long next
= 0;
934 struct blk_mq_hw_ctx
*hctx
;
937 /* A deadlock might occur if a request is stuck requiring a
938 * timeout at the same time a queue freeze is waiting
939 * completion, since the timeout code would not be able to
940 * acquire the queue reference here.
942 * That's why we don't use blk_queue_enter here; instead, we use
943 * percpu_ref_tryget directly, because we need to be able to
944 * obtain a reference even in the short window between the queue
945 * starting to freeze, by dropping the first reference in
946 * blk_freeze_queue_start, and the moment the last request is
947 * consumed, marked by the instant q_usage_counter reaches
950 if (!percpu_ref_tryget(&q
->q_usage_counter
))
953 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_expired
, &next
);
956 mod_timer(&q
->timeout
, next
);
959 * Request timeouts are handled as a forward rolling timer. If
960 * we end up here it means that no requests are pending and
961 * also that no request has been pending for a while. Mark
964 queue_for_each_hw_ctx(q
, hctx
, i
) {
965 /* the hctx may be unmapped, so check it here */
966 if (blk_mq_hw_queue_mapped(hctx
))
967 blk_mq_tag_idle(hctx
);
973 struct flush_busy_ctx_data
{
974 struct blk_mq_hw_ctx
*hctx
;
975 struct list_head
*list
;
978 static bool flush_busy_ctx(struct sbitmap
*sb
, unsigned int bitnr
, void *data
)
980 struct flush_busy_ctx_data
*flush_data
= data
;
981 struct blk_mq_hw_ctx
*hctx
= flush_data
->hctx
;
982 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
983 enum hctx_type type
= hctx
->type
;
985 spin_lock(&ctx
->lock
);
986 list_splice_tail_init(&ctx
->rq_lists
[type
], flush_data
->list
);
987 sbitmap_clear_bit(sb
, bitnr
);
988 spin_unlock(&ctx
->lock
);
993 * Process software queues that have been marked busy, splicing them
994 * to the for-dispatch
996 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
998 struct flush_busy_ctx_data data
= {
1003 sbitmap_for_each_set(&hctx
->ctx_map
, flush_busy_ctx
, &data
);
1005 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs
);
1007 struct dispatch_rq_data
{
1008 struct blk_mq_hw_ctx
*hctx
;
1012 static bool dispatch_rq_from_ctx(struct sbitmap
*sb
, unsigned int bitnr
,
1015 struct dispatch_rq_data
*dispatch_data
= data
;
1016 struct blk_mq_hw_ctx
*hctx
= dispatch_data
->hctx
;
1017 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
1018 enum hctx_type type
= hctx
->type
;
1020 spin_lock(&ctx
->lock
);
1021 if (!list_empty(&ctx
->rq_lists
[type
])) {
1022 dispatch_data
->rq
= list_entry_rq(ctx
->rq_lists
[type
].next
);
1023 list_del_init(&dispatch_data
->rq
->queuelist
);
1024 if (list_empty(&ctx
->rq_lists
[type
]))
1025 sbitmap_clear_bit(sb
, bitnr
);
1027 spin_unlock(&ctx
->lock
);
1029 return !dispatch_data
->rq
;
1032 struct request
*blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx
*hctx
,
1033 struct blk_mq_ctx
*start
)
1035 unsigned off
= start
? start
->index_hw
[hctx
->type
] : 0;
1036 struct dispatch_rq_data data
= {
1041 __sbitmap_for_each_set(&hctx
->ctx_map
, off
,
1042 dispatch_rq_from_ctx
, &data
);
1047 static inline unsigned int queued_to_index(unsigned int queued
)
1052 return min(BLK_MQ_MAX_DISPATCH_ORDER
- 1, ilog2(queued
) + 1);
1055 static int blk_mq_dispatch_wake(wait_queue_entry_t
*wait
, unsigned mode
,
1056 int flags
, void *key
)
1058 struct blk_mq_hw_ctx
*hctx
;
1060 hctx
= container_of(wait
, struct blk_mq_hw_ctx
, dispatch_wait
);
1062 spin_lock(&hctx
->dispatch_wait_lock
);
1063 if (!list_empty(&wait
->entry
)) {
1064 struct sbitmap_queue
*sbq
;
1066 list_del_init(&wait
->entry
);
1067 sbq
= &hctx
->tags
->bitmap_tags
;
1068 atomic_dec(&sbq
->ws_active
);
1070 spin_unlock(&hctx
->dispatch_wait_lock
);
1072 blk_mq_run_hw_queue(hctx
, true);
1077 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1078 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1079 * restart. For both cases, take care to check the condition again after
1080 * marking us as waiting.
1082 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx
*hctx
,
1085 struct sbitmap_queue
*sbq
= &hctx
->tags
->bitmap_tags
;
1086 struct wait_queue_head
*wq
;
1087 wait_queue_entry_t
*wait
;
1090 if (!(hctx
->flags
& BLK_MQ_F_TAG_SHARED
)) {
1091 blk_mq_sched_mark_restart_hctx(hctx
);
1094 * It's possible that a tag was freed in the window between the
1095 * allocation failure and adding the hardware queue to the wait
1098 * Don't clear RESTART here, someone else could have set it.
1099 * At most this will cost an extra queue run.
1101 return blk_mq_get_driver_tag(rq
);
1104 wait
= &hctx
->dispatch_wait
;
1105 if (!list_empty_careful(&wait
->entry
))
1108 wq
= &bt_wait_ptr(sbq
, hctx
)->wait
;
1110 spin_lock_irq(&wq
->lock
);
1111 spin_lock(&hctx
->dispatch_wait_lock
);
1112 if (!list_empty(&wait
->entry
)) {
1113 spin_unlock(&hctx
->dispatch_wait_lock
);
1114 spin_unlock_irq(&wq
->lock
);
1118 atomic_inc(&sbq
->ws_active
);
1119 wait
->flags
&= ~WQ_FLAG_EXCLUSIVE
;
1120 __add_wait_queue(wq
, wait
);
1123 * It's possible that a tag was freed in the window between the
1124 * allocation failure and adding the hardware queue to the wait
1127 ret
= blk_mq_get_driver_tag(rq
);
1129 spin_unlock(&hctx
->dispatch_wait_lock
);
1130 spin_unlock_irq(&wq
->lock
);
1135 * We got a tag, remove ourselves from the wait queue to ensure
1136 * someone else gets the wakeup.
1138 list_del_init(&wait
->entry
);
1139 atomic_dec(&sbq
->ws_active
);
1140 spin_unlock(&hctx
->dispatch_wait_lock
);
1141 spin_unlock_irq(&wq
->lock
);
1146 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1147 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1149 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1150 * - EWMA is one simple way to compute running average value
1151 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1152 * - take 4 as factor for avoiding to get too small(0) result, and this
1153 * factor doesn't matter because EWMA decreases exponentially
1155 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx
*hctx
, bool busy
)
1159 if (hctx
->queue
->elevator
)
1162 ewma
= hctx
->dispatch_busy
;
1167 ewma
*= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
- 1;
1169 ewma
+= 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR
;
1170 ewma
/= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
;
1172 hctx
->dispatch_busy
= ewma
;
1175 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1177 static void blk_mq_handle_dev_resource(struct request
*rq
,
1178 struct list_head
*list
)
1180 struct request
*next
=
1181 list_first_entry_or_null(list
, struct request
, queuelist
);
1184 * If an I/O scheduler has been configured and we got a driver tag for
1185 * the next request already, free it.
1188 blk_mq_put_driver_tag(next
);
1190 list_add(&rq
->queuelist
, list
);
1191 __blk_mq_requeue_request(rq
);
1194 static void blk_mq_handle_zone_resource(struct request
*rq
,
1195 struct list_head
*zone_list
)
1198 * If we end up here it is because we cannot dispatch a request to a
1199 * specific zone due to LLD level zone-write locking or other zone
1200 * related resource not being available. In this case, set the request
1201 * aside in zone_list for retrying it later.
1203 list_add(&rq
->queuelist
, zone_list
);
1204 __blk_mq_requeue_request(rq
);
1208 * Returns true if we did some work AND can potentially do more.
1210 bool blk_mq_dispatch_rq_list(struct request_queue
*q
, struct list_head
*list
,
1213 struct blk_mq_hw_ctx
*hctx
;
1214 struct request
*rq
, *nxt
;
1215 bool no_tag
= false;
1217 blk_status_t ret
= BLK_STS_OK
;
1218 bool no_budget_avail
= false;
1219 LIST_HEAD(zone_list
);
1221 if (list_empty(list
))
1224 WARN_ON(!list_is_singular(list
) && got_budget
);
1227 * Now process all the entries, sending them to the driver.
1229 errors
= queued
= 0;
1231 struct blk_mq_queue_data bd
;
1233 rq
= list_first_entry(list
, struct request
, queuelist
);
1236 if (!got_budget
&& !blk_mq_get_dispatch_budget(hctx
)) {
1237 blk_mq_put_driver_tag(rq
);
1238 no_budget_avail
= true;
1242 if (!blk_mq_get_driver_tag(rq
)) {
1244 * The initial allocation attempt failed, so we need to
1245 * rerun the hardware queue when a tag is freed. The
1246 * waitqueue takes care of that. If the queue is run
1247 * before we add this entry back on the dispatch list,
1248 * we'll re-run it below.
1250 if (!blk_mq_mark_tag_wait(hctx
, rq
)) {
1251 blk_mq_put_dispatch_budget(hctx
);
1253 * For non-shared tags, the RESTART check
1256 if (hctx
->flags
& BLK_MQ_F_TAG_SHARED
)
1262 list_del_init(&rq
->queuelist
);
1267 * Flag last if we have no more requests, or if we have more
1268 * but can't assign a driver tag to it.
1270 if (list_empty(list
))
1273 nxt
= list_first_entry(list
, struct request
, queuelist
);
1274 bd
.last
= !blk_mq_get_driver_tag(nxt
);
1277 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1278 if (ret
== BLK_STS_RESOURCE
|| ret
== BLK_STS_DEV_RESOURCE
) {
1279 blk_mq_handle_dev_resource(rq
, list
);
1281 } else if (ret
== BLK_STS_ZONE_RESOURCE
) {
1283 * Move the request to zone_list and keep going through
1284 * the dispatch list to find more requests the drive can
1287 blk_mq_handle_zone_resource(rq
, &zone_list
);
1288 if (list_empty(list
))
1293 if (unlikely(ret
!= BLK_STS_OK
)) {
1295 blk_mq_end_request(rq
, BLK_STS_IOERR
);
1300 } while (!list_empty(list
));
1302 if (!list_empty(&zone_list
))
1303 list_splice_tail_init(&zone_list
, list
);
1305 hctx
->dispatched
[queued_to_index(queued
)]++;
1308 * Any items that need requeuing? Stuff them into hctx->dispatch,
1309 * that is where we will continue on next queue run.
1311 if (!list_empty(list
)) {
1315 * If we didn't flush the entire list, we could have told
1316 * the driver there was more coming, but that turned out to
1319 if (q
->mq_ops
->commit_rqs
&& queued
)
1320 q
->mq_ops
->commit_rqs(hctx
);
1322 spin_lock(&hctx
->lock
);
1323 list_splice_tail_init(list
, &hctx
->dispatch
);
1324 spin_unlock(&hctx
->lock
);
1327 * If SCHED_RESTART was set by the caller of this function and
1328 * it is no longer set that means that it was cleared by another
1329 * thread and hence that a queue rerun is needed.
1331 * If 'no_tag' is set, that means that we failed getting
1332 * a driver tag with an I/O scheduler attached. If our dispatch
1333 * waitqueue is no longer active, ensure that we run the queue
1334 * AFTER adding our entries back to the list.
1336 * If no I/O scheduler has been configured it is possible that
1337 * the hardware queue got stopped and restarted before requests
1338 * were pushed back onto the dispatch list. Rerun the queue to
1339 * avoid starvation. Notes:
1340 * - blk_mq_run_hw_queue() checks whether or not a queue has
1341 * been stopped before rerunning a queue.
1342 * - Some but not all block drivers stop a queue before
1343 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
1346 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
1347 * bit is set, run queue after a delay to avoid IO stalls
1348 * that could otherwise occur if the queue is idle. We'll do
1349 * similar if we couldn't get budget and SCHED_RESTART is set.
1351 needs_restart
= blk_mq_sched_needs_restart(hctx
);
1352 if (!needs_restart
||
1353 (no_tag
&& list_empty_careful(&hctx
->dispatch_wait
.entry
)))
1354 blk_mq_run_hw_queue(hctx
, true);
1355 else if (needs_restart
&& (ret
== BLK_STS_RESOURCE
||
1357 blk_mq_delay_run_hw_queue(hctx
, BLK_MQ_RESOURCE_DELAY
);
1359 blk_mq_update_dispatch_busy(hctx
, true);
1362 blk_mq_update_dispatch_busy(hctx
, false);
1365 * If the host/device is unable to accept more work, inform the
1368 if (ret
== BLK_STS_RESOURCE
|| ret
== BLK_STS_DEV_RESOURCE
)
1371 return (queued
+ errors
) != 0;
1375 * __blk_mq_run_hw_queue - Run a hardware queue.
1376 * @hctx: Pointer to the hardware queue to run.
1378 * Send pending requests to the hardware.
1380 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1385 * We should be running this queue from one of the CPUs that
1388 * There are at least two related races now between setting
1389 * hctx->next_cpu from blk_mq_hctx_next_cpu() and running
1390 * __blk_mq_run_hw_queue():
1392 * - hctx->next_cpu is found offline in blk_mq_hctx_next_cpu(),
1393 * but later it becomes online, then this warning is harmless
1396 * - hctx->next_cpu is found online in blk_mq_hctx_next_cpu(),
1397 * but later it becomes offline, then the warning can't be
1398 * triggered, and we depend on blk-mq timeout handler to
1399 * handle dispatched requests to this hctx
1401 if (!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
) &&
1402 cpu_online(hctx
->next_cpu
)) {
1403 printk(KERN_WARNING
"run queue from wrong CPU %d, hctx %s\n",
1404 raw_smp_processor_id(),
1405 cpumask_empty(hctx
->cpumask
) ? "inactive": "active");
1410 * We can't run the queue inline with ints disabled. Ensure that
1411 * we catch bad users of this early.
1413 WARN_ON_ONCE(in_interrupt());
1415 might_sleep_if(hctx
->flags
& BLK_MQ_F_BLOCKING
);
1417 hctx_lock(hctx
, &srcu_idx
);
1418 blk_mq_sched_dispatch_requests(hctx
);
1419 hctx_unlock(hctx
, srcu_idx
);
1422 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx
*hctx
)
1424 int cpu
= cpumask_first_and(hctx
->cpumask
, cpu_online_mask
);
1426 if (cpu
>= nr_cpu_ids
)
1427 cpu
= cpumask_first(hctx
->cpumask
);
1432 * It'd be great if the workqueue API had a way to pass
1433 * in a mask and had some smarts for more clever placement.
1434 * For now we just round-robin here, switching for every
1435 * BLK_MQ_CPU_WORK_BATCH queued items.
1437 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
1440 int next_cpu
= hctx
->next_cpu
;
1442 if (hctx
->queue
->nr_hw_queues
== 1)
1443 return WORK_CPU_UNBOUND
;
1445 if (--hctx
->next_cpu_batch
<= 0) {
1447 next_cpu
= cpumask_next_and(next_cpu
, hctx
->cpumask
,
1449 if (next_cpu
>= nr_cpu_ids
)
1450 next_cpu
= blk_mq_first_mapped_cpu(hctx
);
1451 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1455 * Do unbound schedule if we can't find a online CPU for this hctx,
1456 * and it should only happen in the path of handling CPU DEAD.
1458 if (!cpu_online(next_cpu
)) {
1465 * Make sure to re-select CPU next time once after CPUs
1466 * in hctx->cpumask become online again.
1468 hctx
->next_cpu
= next_cpu
;
1469 hctx
->next_cpu_batch
= 1;
1470 return WORK_CPU_UNBOUND
;
1473 hctx
->next_cpu
= next_cpu
;
1478 * __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue.
1479 * @hctx: Pointer to the hardware queue to run.
1480 * @async: If we want to run the queue asynchronously.
1481 * @msecs: Microseconds of delay to wait before running the queue.
1483 * If !@async, try to run the queue now. Else, run the queue asynchronously and
1484 * with a delay of @msecs.
1486 static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
,
1487 unsigned long msecs
)
1489 if (unlikely(blk_mq_hctx_stopped(hctx
)))
1492 if (!async
&& !(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1493 int cpu
= get_cpu();
1494 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
1495 __blk_mq_run_hw_queue(hctx
);
1503 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx
), &hctx
->run_work
,
1504 msecs_to_jiffies(msecs
));
1508 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
1509 * @hctx: Pointer to the hardware queue to run.
1510 * @msecs: Microseconds of delay to wait before running the queue.
1512 * Run a hardware queue asynchronously with a delay of @msecs.
1514 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1516 __blk_mq_delay_run_hw_queue(hctx
, true, msecs
);
1518 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue
);
1521 * blk_mq_run_hw_queue - Start to run a hardware queue.
1522 * @hctx: Pointer to the hardware queue to run.
1523 * @async: If we want to run the queue asynchronously.
1525 * Check if the request queue is not in a quiesced state and if there are
1526 * pending requests to be sent. If this is true, run the queue to send requests
1529 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1535 * When queue is quiesced, we may be switching io scheduler, or
1536 * updating nr_hw_queues, or other things, and we can't run queue
1537 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
1539 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
1542 hctx_lock(hctx
, &srcu_idx
);
1543 need_run
= !blk_queue_quiesced(hctx
->queue
) &&
1544 blk_mq_hctx_has_pending(hctx
);
1545 hctx_unlock(hctx
, srcu_idx
);
1548 __blk_mq_delay_run_hw_queue(hctx
, async
, 0);
1550 EXPORT_SYMBOL(blk_mq_run_hw_queue
);
1553 * blk_mq_run_hw_queue - Run all hardware queues in a request queue.
1554 * @q: Pointer to the request queue to run.
1555 * @async: If we want to run the queue asynchronously.
1557 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
1559 struct blk_mq_hw_ctx
*hctx
;
1562 queue_for_each_hw_ctx(q
, hctx
, i
) {
1563 if (blk_mq_hctx_stopped(hctx
))
1566 blk_mq_run_hw_queue(hctx
, async
);
1569 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
1572 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
1573 * @q: Pointer to the request queue to run.
1574 * @msecs: Microseconds of delay to wait before running the queues.
1576 void blk_mq_delay_run_hw_queues(struct request_queue
*q
, unsigned long msecs
)
1578 struct blk_mq_hw_ctx
*hctx
;
1581 queue_for_each_hw_ctx(q
, hctx
, i
) {
1582 if (blk_mq_hctx_stopped(hctx
))
1585 blk_mq_delay_run_hw_queue(hctx
, msecs
);
1588 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues
);
1591 * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
1592 * @q: request queue.
1594 * The caller is responsible for serializing this function against
1595 * blk_mq_{start,stop}_hw_queue().
1597 bool blk_mq_queue_stopped(struct request_queue
*q
)
1599 struct blk_mq_hw_ctx
*hctx
;
1602 queue_for_each_hw_ctx(q
, hctx
, i
)
1603 if (blk_mq_hctx_stopped(hctx
))
1608 EXPORT_SYMBOL(blk_mq_queue_stopped
);
1611 * This function is often used for pausing .queue_rq() by driver when
1612 * there isn't enough resource or some conditions aren't satisfied, and
1613 * BLK_STS_RESOURCE is usually returned.
1615 * We do not guarantee that dispatch can be drained or blocked
1616 * after blk_mq_stop_hw_queue() returns. Please use
1617 * blk_mq_quiesce_queue() for that requirement.
1619 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1621 cancel_delayed_work(&hctx
->run_work
);
1623 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1625 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
1628 * This function is often used for pausing .queue_rq() by driver when
1629 * there isn't enough resource or some conditions aren't satisfied, and
1630 * BLK_STS_RESOURCE is usually returned.
1632 * We do not guarantee that dispatch can be drained or blocked
1633 * after blk_mq_stop_hw_queues() returns. Please use
1634 * blk_mq_quiesce_queue() for that requirement.
1636 void blk_mq_stop_hw_queues(struct request_queue
*q
)
1638 struct blk_mq_hw_ctx
*hctx
;
1641 queue_for_each_hw_ctx(q
, hctx
, i
)
1642 blk_mq_stop_hw_queue(hctx
);
1644 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
1646 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1648 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1650 blk_mq_run_hw_queue(hctx
, false);
1652 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
1654 void blk_mq_start_hw_queues(struct request_queue
*q
)
1656 struct blk_mq_hw_ctx
*hctx
;
1659 queue_for_each_hw_ctx(q
, hctx
, i
)
1660 blk_mq_start_hw_queue(hctx
);
1662 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
1664 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1666 if (!blk_mq_hctx_stopped(hctx
))
1669 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1670 blk_mq_run_hw_queue(hctx
, async
);
1672 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue
);
1674 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
1676 struct blk_mq_hw_ctx
*hctx
;
1679 queue_for_each_hw_ctx(q
, hctx
, i
)
1680 blk_mq_start_stopped_hw_queue(hctx
, async
);
1682 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
1684 static void blk_mq_run_work_fn(struct work_struct
*work
)
1686 struct blk_mq_hw_ctx
*hctx
;
1688 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
1691 * If we are stopped, don't run the queue.
1693 if (test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
1696 __blk_mq_run_hw_queue(hctx
);
1699 static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx
*hctx
,
1703 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1704 enum hctx_type type
= hctx
->type
;
1706 lockdep_assert_held(&ctx
->lock
);
1708 trace_block_rq_insert(hctx
->queue
, rq
);
1711 list_add(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
1713 list_add_tail(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
1716 void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
1719 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1721 lockdep_assert_held(&ctx
->lock
);
1723 __blk_mq_insert_req_list(hctx
, rq
, at_head
);
1724 blk_mq_hctx_mark_pending(hctx
, ctx
);
1728 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
1729 * @rq: Pointer to request to be inserted.
1730 * @run_queue: If we should run the hardware queue after inserting the request.
1732 * Should only be used carefully, when the caller knows we want to
1733 * bypass a potential IO scheduler on the target device.
1735 void blk_mq_request_bypass_insert(struct request
*rq
, bool at_head
,
1738 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
1740 spin_lock(&hctx
->lock
);
1742 list_add(&rq
->queuelist
, &hctx
->dispatch
);
1744 list_add_tail(&rq
->queuelist
, &hctx
->dispatch
);
1745 spin_unlock(&hctx
->lock
);
1748 blk_mq_run_hw_queue(hctx
, false);
1751 void blk_mq_insert_requests(struct blk_mq_hw_ctx
*hctx
, struct blk_mq_ctx
*ctx
,
1752 struct list_head
*list
)
1756 enum hctx_type type
= hctx
->type
;
1759 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1762 list_for_each_entry(rq
, list
, queuelist
) {
1763 BUG_ON(rq
->mq_ctx
!= ctx
);
1764 trace_block_rq_insert(hctx
->queue
, rq
);
1767 spin_lock(&ctx
->lock
);
1768 list_splice_tail_init(list
, &ctx
->rq_lists
[type
]);
1769 blk_mq_hctx_mark_pending(hctx
, ctx
);
1770 spin_unlock(&ctx
->lock
);
1773 static int plug_rq_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1775 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1776 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1778 if (rqa
->mq_ctx
!= rqb
->mq_ctx
)
1779 return rqa
->mq_ctx
> rqb
->mq_ctx
;
1780 if (rqa
->mq_hctx
!= rqb
->mq_hctx
)
1781 return rqa
->mq_hctx
> rqb
->mq_hctx
;
1783 return blk_rq_pos(rqa
) > blk_rq_pos(rqb
);
1786 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1790 if (list_empty(&plug
->mq_list
))
1792 list_splice_init(&plug
->mq_list
, &list
);
1794 if (plug
->rq_count
> 2 && plug
->multiple_queues
)
1795 list_sort(NULL
, &list
, plug_rq_cmp
);
1800 struct list_head rq_list
;
1801 struct request
*rq
, *head_rq
= list_entry_rq(list
.next
);
1802 struct list_head
*pos
= &head_rq
->queuelist
; /* skip first */
1803 struct blk_mq_hw_ctx
*this_hctx
= head_rq
->mq_hctx
;
1804 struct blk_mq_ctx
*this_ctx
= head_rq
->mq_ctx
;
1805 unsigned int depth
= 1;
1807 list_for_each_continue(pos
, &list
) {
1808 rq
= list_entry_rq(pos
);
1810 if (rq
->mq_hctx
!= this_hctx
|| rq
->mq_ctx
!= this_ctx
)
1815 list_cut_before(&rq_list
, &list
, pos
);
1816 trace_block_unplug(head_rq
->q
, depth
, !from_schedule
);
1817 blk_mq_sched_insert_requests(this_hctx
, this_ctx
, &rq_list
,
1819 } while(!list_empty(&list
));
1822 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
,
1823 unsigned int nr_segs
)
1825 if (bio
->bi_opf
& REQ_RAHEAD
)
1826 rq
->cmd_flags
|= REQ_FAILFAST_MASK
;
1828 rq
->__sector
= bio
->bi_iter
.bi_sector
;
1829 rq
->write_hint
= bio
->bi_write_hint
;
1830 blk_rq_bio_prep(rq
, bio
, nr_segs
);
1831 blk_crypto_rq_bio_prep(rq
, bio
, GFP_NOIO
);
1833 blk_account_io_start(rq
);
1836 static blk_status_t
__blk_mq_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1838 blk_qc_t
*cookie
, bool last
)
1840 struct request_queue
*q
= rq
->q
;
1841 struct blk_mq_queue_data bd
= {
1845 blk_qc_t new_cookie
;
1848 new_cookie
= request_to_qc_t(hctx
, rq
);
1851 * For OK queue, we are done. For error, caller may kill it.
1852 * Any other error (busy), just add it to our list as we
1853 * previously would have done.
1855 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1858 blk_mq_update_dispatch_busy(hctx
, false);
1859 *cookie
= new_cookie
;
1861 case BLK_STS_RESOURCE
:
1862 case BLK_STS_DEV_RESOURCE
:
1863 blk_mq_update_dispatch_busy(hctx
, true);
1864 __blk_mq_requeue_request(rq
);
1867 blk_mq_update_dispatch_busy(hctx
, false);
1868 *cookie
= BLK_QC_T_NONE
;
1875 static blk_status_t
__blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1878 bool bypass_insert
, bool last
)
1880 struct request_queue
*q
= rq
->q
;
1881 bool run_queue
= true;
1884 * RCU or SRCU read lock is needed before checking quiesced flag.
1886 * When queue is stopped or quiesced, ignore 'bypass_insert' from
1887 * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
1888 * and avoid driver to try to dispatch again.
1890 if (blk_mq_hctx_stopped(hctx
) || blk_queue_quiesced(q
)) {
1892 bypass_insert
= false;
1896 if (q
->elevator
&& !bypass_insert
)
1899 if (!blk_mq_get_dispatch_budget(hctx
))
1902 if (!blk_mq_get_driver_tag(rq
)) {
1903 blk_mq_put_dispatch_budget(hctx
);
1907 return __blk_mq_issue_directly(hctx
, rq
, cookie
, last
);
1910 return BLK_STS_RESOURCE
;
1912 blk_mq_request_bypass_insert(rq
, false, run_queue
);
1917 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
1918 * @hctx: Pointer of the associated hardware queue.
1919 * @rq: Pointer to request to be sent.
1920 * @cookie: Request queue cookie.
1922 * If the device has enough resources to accept a new request now, send the
1923 * request directly to device driver. Else, insert at hctx->dispatch queue, so
1924 * we can try send it another time in the future. Requests inserted at this
1925 * queue have higher priority.
1927 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1928 struct request
*rq
, blk_qc_t
*cookie
)
1933 might_sleep_if(hctx
->flags
& BLK_MQ_F_BLOCKING
);
1935 hctx_lock(hctx
, &srcu_idx
);
1937 ret
= __blk_mq_try_issue_directly(hctx
, rq
, cookie
, false, true);
1938 if (ret
== BLK_STS_RESOURCE
|| ret
== BLK_STS_DEV_RESOURCE
)
1939 blk_mq_request_bypass_insert(rq
, false, true);
1940 else if (ret
!= BLK_STS_OK
)
1941 blk_mq_end_request(rq
, ret
);
1943 hctx_unlock(hctx
, srcu_idx
);
1946 blk_status_t
blk_mq_request_issue_directly(struct request
*rq
, bool last
)
1950 blk_qc_t unused_cookie
;
1951 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
1953 hctx_lock(hctx
, &srcu_idx
);
1954 ret
= __blk_mq_try_issue_directly(hctx
, rq
, &unused_cookie
, true, last
);
1955 hctx_unlock(hctx
, srcu_idx
);
1960 void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx
*hctx
,
1961 struct list_head
*list
)
1965 while (!list_empty(list
)) {
1967 struct request
*rq
= list_first_entry(list
, struct request
,
1970 list_del_init(&rq
->queuelist
);
1971 ret
= blk_mq_request_issue_directly(rq
, list_empty(list
));
1972 if (ret
!= BLK_STS_OK
) {
1973 if (ret
== BLK_STS_RESOURCE
||
1974 ret
== BLK_STS_DEV_RESOURCE
) {
1975 blk_mq_request_bypass_insert(rq
, false,
1979 blk_mq_end_request(rq
, ret
);
1985 * If we didn't flush the entire list, we could have told
1986 * the driver there was more coming, but that turned out to
1989 if (!list_empty(list
) && hctx
->queue
->mq_ops
->commit_rqs
&& queued
)
1990 hctx
->queue
->mq_ops
->commit_rqs(hctx
);
1993 static void blk_add_rq_to_plug(struct blk_plug
*plug
, struct request
*rq
)
1995 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1997 if (!plug
->multiple_queues
&& !list_is_singular(&plug
->mq_list
)) {
1998 struct request
*tmp
;
2000 tmp
= list_first_entry(&plug
->mq_list
, struct request
,
2002 if (tmp
->q
!= rq
->q
)
2003 plug
->multiple_queues
= true;
2008 * blk_mq_make_request - Create and send a request to block device.
2009 * @q: Request queue pointer.
2010 * @bio: Bio pointer.
2012 * Builds up a request structure from @q and @bio and send to the device. The
2013 * request may not be queued directly to hardware if:
2014 * * This request can be merged with another one
2015 * * We want to place request at plug queue for possible future merging
2016 * * There is an IO scheduler active at this queue
2018 * It will not queue the request if there is an error with the bio, or at the
2021 * Returns: Request queue cookie.
2023 blk_qc_t
blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
2025 const int is_sync
= op_is_sync(bio
->bi_opf
);
2026 const int is_flush_fua
= op_is_flush(bio
->bi_opf
);
2027 struct blk_mq_alloc_data data
= {
2031 struct blk_plug
*plug
;
2032 struct request
*same_queue_rq
= NULL
;
2033 unsigned int nr_segs
;
2037 blk_queue_bounce(q
, &bio
);
2038 __blk_queue_split(q
, &bio
, &nr_segs
);
2040 if (!bio_integrity_prep(bio
))
2043 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
2044 blk_attempt_plug_merge(q
, bio
, nr_segs
, &same_queue_rq
))
2047 if (blk_mq_sched_bio_merge(q
, bio
, nr_segs
))
2050 rq_qos_throttle(q
, bio
);
2052 data
.cmd_flags
= bio
->bi_opf
;
2053 rq
= __blk_mq_alloc_request(&data
);
2054 if (unlikely(!rq
)) {
2055 rq_qos_cleanup(q
, bio
);
2056 if (bio
->bi_opf
& REQ_NOWAIT
)
2057 bio_wouldblock_error(bio
);
2061 trace_block_getrq(q
, bio
, bio
->bi_opf
);
2063 rq_qos_track(q
, rq
, bio
);
2065 cookie
= request_to_qc_t(data
.hctx
, rq
);
2067 blk_mq_bio_to_request(rq
, bio
, nr_segs
);
2069 ret
= blk_crypto_init_request(rq
);
2070 if (ret
!= BLK_STS_OK
) {
2071 bio
->bi_status
= ret
;
2073 blk_mq_free_request(rq
);
2074 return BLK_QC_T_NONE
;
2077 plug
= blk_mq_plug(q
, bio
);
2078 if (unlikely(is_flush_fua
)) {
2079 /* Bypass scheduler for flush requests */
2080 blk_insert_flush(rq
);
2081 blk_mq_run_hw_queue(data
.hctx
, true);
2082 } else if (plug
&& (q
->nr_hw_queues
== 1 || q
->mq_ops
->commit_rqs
||
2083 !blk_queue_nonrot(q
))) {
2085 * Use plugging if we have a ->commit_rqs() hook as well, as
2086 * we know the driver uses bd->last in a smart fashion.
2088 * Use normal plugging if this disk is slow HDD, as sequential
2089 * IO may benefit a lot from plug merging.
2091 unsigned int request_count
= plug
->rq_count
;
2092 struct request
*last
= NULL
;
2095 trace_block_plug(q
);
2097 last
= list_entry_rq(plug
->mq_list
.prev
);
2099 if (request_count
>= BLK_MAX_REQUEST_COUNT
|| (last
&&
2100 blk_rq_bytes(last
) >= BLK_PLUG_FLUSH_SIZE
)) {
2101 blk_flush_plug_list(plug
, false);
2102 trace_block_plug(q
);
2105 blk_add_rq_to_plug(plug
, rq
);
2106 } else if (q
->elevator
) {
2107 /* Insert the request at the IO scheduler queue */
2108 blk_mq_sched_insert_request(rq
, false, true, true);
2109 } else if (plug
&& !blk_queue_nomerges(q
)) {
2111 * We do limited plugging. If the bio can be merged, do that.
2112 * Otherwise the existing request in the plug list will be
2113 * issued. So the plug list will have one request at most
2114 * The plug list might get flushed before this. If that happens,
2115 * the plug list is empty, and same_queue_rq is invalid.
2117 if (list_empty(&plug
->mq_list
))
2118 same_queue_rq
= NULL
;
2119 if (same_queue_rq
) {
2120 list_del_init(&same_queue_rq
->queuelist
);
2123 blk_add_rq_to_plug(plug
, rq
);
2124 trace_block_plug(q
);
2126 if (same_queue_rq
) {
2127 data
.hctx
= same_queue_rq
->mq_hctx
;
2128 trace_block_unplug(q
, 1, true);
2129 blk_mq_try_issue_directly(data
.hctx
, same_queue_rq
,
2132 } else if ((q
->nr_hw_queues
> 1 && is_sync
) ||
2133 !data
.hctx
->dispatch_busy
) {
2135 * There is no scheduler and we can try to send directly
2138 blk_mq_try_issue_directly(data
.hctx
, rq
, &cookie
);
2141 blk_mq_sched_insert_request(rq
, false, true, true);
2147 return BLK_QC_T_NONE
;
2149 EXPORT_SYMBOL_GPL(blk_mq_make_request
); /* only for request based dm */
2151 void blk_mq_free_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
2152 unsigned int hctx_idx
)
2156 if (tags
->rqs
&& set
->ops
->exit_request
) {
2159 for (i
= 0; i
< tags
->nr_tags
; i
++) {
2160 struct request
*rq
= tags
->static_rqs
[i
];
2164 set
->ops
->exit_request(set
, rq
, hctx_idx
);
2165 tags
->static_rqs
[i
] = NULL
;
2169 while (!list_empty(&tags
->page_list
)) {
2170 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
2171 list_del_init(&page
->lru
);
2173 * Remove kmemleak object previously allocated in
2174 * blk_mq_alloc_rqs().
2176 kmemleak_free(page_address(page
));
2177 __free_pages(page
, page
->private);
2181 void blk_mq_free_rq_map(struct blk_mq_tags
*tags
)
2185 kfree(tags
->static_rqs
);
2186 tags
->static_rqs
= NULL
;
2188 blk_mq_free_tags(tags
);
2191 struct blk_mq_tags
*blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
,
2192 unsigned int hctx_idx
,
2193 unsigned int nr_tags
,
2194 unsigned int reserved_tags
)
2196 struct blk_mq_tags
*tags
;
2199 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], hctx_idx
);
2200 if (node
== NUMA_NO_NODE
)
2201 node
= set
->numa_node
;
2203 tags
= blk_mq_init_tags(nr_tags
, reserved_tags
, node
,
2204 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
2208 tags
->rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
2209 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
2212 blk_mq_free_tags(tags
);
2216 tags
->static_rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
2217 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
2219 if (!tags
->static_rqs
) {
2221 blk_mq_free_tags(tags
);
2228 static size_t order_to_size(unsigned int order
)
2230 return (size_t)PAGE_SIZE
<< order
;
2233 static int blk_mq_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
2234 unsigned int hctx_idx
, int node
)
2238 if (set
->ops
->init_request
) {
2239 ret
= set
->ops
->init_request(set
, rq
, hctx_idx
, node
);
2244 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
2248 int blk_mq_alloc_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
2249 unsigned int hctx_idx
, unsigned int depth
)
2251 unsigned int i
, j
, entries_per_page
, max_order
= 4;
2252 size_t rq_size
, left
;
2255 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], hctx_idx
);
2256 if (node
== NUMA_NO_NODE
)
2257 node
= set
->numa_node
;
2259 INIT_LIST_HEAD(&tags
->page_list
);
2262 * rq_size is the size of the request plus driver payload, rounded
2263 * to the cacheline size
2265 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
2267 left
= rq_size
* depth
;
2269 for (i
= 0; i
< depth
; ) {
2270 int this_order
= max_order
;
2275 while (this_order
&& left
< order_to_size(this_order
- 1))
2279 page
= alloc_pages_node(node
,
2280 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
2286 if (order_to_size(this_order
) < rq_size
)
2293 page
->private = this_order
;
2294 list_add_tail(&page
->lru
, &tags
->page_list
);
2296 p
= page_address(page
);
2298 * Allow kmemleak to scan these pages as they contain pointers
2299 * to additional allocations like via ops->init_request().
2301 kmemleak_alloc(p
, order_to_size(this_order
), 1, GFP_NOIO
);
2302 entries_per_page
= order_to_size(this_order
) / rq_size
;
2303 to_do
= min(entries_per_page
, depth
- i
);
2304 left
-= to_do
* rq_size
;
2305 for (j
= 0; j
< to_do
; j
++) {
2306 struct request
*rq
= p
;
2308 tags
->static_rqs
[i
] = rq
;
2309 if (blk_mq_init_request(set
, rq
, hctx_idx
, node
)) {
2310 tags
->static_rqs
[i
] = NULL
;
2321 blk_mq_free_rqs(set
, tags
, hctx_idx
);
2325 struct rq_iter_data
{
2326 struct blk_mq_hw_ctx
*hctx
;
2330 static bool blk_mq_has_request(struct request
*rq
, void *data
, bool reserved
)
2332 struct rq_iter_data
*iter_data
= data
;
2334 if (rq
->mq_hctx
!= iter_data
->hctx
)
2336 iter_data
->has_rq
= true;
2340 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx
*hctx
)
2342 struct blk_mq_tags
*tags
= hctx
->sched_tags
?
2343 hctx
->sched_tags
: hctx
->tags
;
2344 struct rq_iter_data data
= {
2348 blk_mq_all_tag_iter(tags
, blk_mq_has_request
, &data
);
2352 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu
,
2353 struct blk_mq_hw_ctx
*hctx
)
2355 if (cpumask_next_and(-1, hctx
->cpumask
, cpu_online_mask
) != cpu
)
2357 if (cpumask_next_and(cpu
, hctx
->cpumask
, cpu_online_mask
) < nr_cpu_ids
)
2362 static int blk_mq_hctx_notify_offline(unsigned int cpu
, struct hlist_node
*node
)
2364 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
2365 struct blk_mq_hw_ctx
, cpuhp_online
);
2367 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
) ||
2368 !blk_mq_last_cpu_in_hctx(cpu
, hctx
))
2372 * Prevent new request from being allocated on the current hctx.
2374 * The smp_mb__after_atomic() Pairs with the implied barrier in
2375 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
2376 * seen once we return from the tag allocator.
2378 set_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
2379 smp_mb__after_atomic();
2382 * Try to grab a reference to the queue and wait for any outstanding
2383 * requests. If we could not grab a reference the queue has been
2384 * frozen and there are no requests.
2386 if (percpu_ref_tryget(&hctx
->queue
->q_usage_counter
)) {
2387 while (blk_mq_hctx_has_requests(hctx
))
2389 percpu_ref_put(&hctx
->queue
->q_usage_counter
);
2395 static int blk_mq_hctx_notify_online(unsigned int cpu
, struct hlist_node
*node
)
2397 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
2398 struct blk_mq_hw_ctx
, cpuhp_online
);
2400 if (cpumask_test_cpu(cpu
, hctx
->cpumask
))
2401 clear_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
2406 * 'cpu' is going away. splice any existing rq_list entries from this
2407 * software queue to the hw queue dispatch list, and ensure that it
2410 static int blk_mq_hctx_notify_dead(unsigned int cpu
, struct hlist_node
*node
)
2412 struct blk_mq_hw_ctx
*hctx
;
2413 struct blk_mq_ctx
*ctx
;
2415 enum hctx_type type
;
2417 hctx
= hlist_entry_safe(node
, struct blk_mq_hw_ctx
, cpuhp_dead
);
2418 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
))
2421 ctx
= __blk_mq_get_ctx(hctx
->queue
, cpu
);
2424 spin_lock(&ctx
->lock
);
2425 if (!list_empty(&ctx
->rq_lists
[type
])) {
2426 list_splice_init(&ctx
->rq_lists
[type
], &tmp
);
2427 blk_mq_hctx_clear_pending(hctx
, ctx
);
2429 spin_unlock(&ctx
->lock
);
2431 if (list_empty(&tmp
))
2434 spin_lock(&hctx
->lock
);
2435 list_splice_tail_init(&tmp
, &hctx
->dispatch
);
2436 spin_unlock(&hctx
->lock
);
2438 blk_mq_run_hw_queue(hctx
, true);
2442 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx
*hctx
)
2444 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
2445 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
2446 &hctx
->cpuhp_online
);
2447 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD
,
2451 /* hctx->ctxs will be freed in queue's release handler */
2452 static void blk_mq_exit_hctx(struct request_queue
*q
,
2453 struct blk_mq_tag_set
*set
,
2454 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
2456 if (blk_mq_hw_queue_mapped(hctx
))
2457 blk_mq_tag_idle(hctx
);
2459 if (set
->ops
->exit_request
)
2460 set
->ops
->exit_request(set
, hctx
->fq
->flush_rq
, hctx_idx
);
2462 if (set
->ops
->exit_hctx
)
2463 set
->ops
->exit_hctx(hctx
, hctx_idx
);
2465 blk_mq_remove_cpuhp(hctx
);
2467 spin_lock(&q
->unused_hctx_lock
);
2468 list_add(&hctx
->hctx_list
, &q
->unused_hctx_list
);
2469 spin_unlock(&q
->unused_hctx_lock
);
2472 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
2473 struct blk_mq_tag_set
*set
, int nr_queue
)
2475 struct blk_mq_hw_ctx
*hctx
;
2478 queue_for_each_hw_ctx(q
, hctx
, i
) {
2481 blk_mq_debugfs_unregister_hctx(hctx
);
2482 blk_mq_exit_hctx(q
, set
, hctx
, i
);
2486 static int blk_mq_hw_ctx_size(struct blk_mq_tag_set
*tag_set
)
2488 int hw_ctx_size
= sizeof(struct blk_mq_hw_ctx
);
2490 BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx
, srcu
),
2491 __alignof__(struct blk_mq_hw_ctx
)) !=
2492 sizeof(struct blk_mq_hw_ctx
));
2494 if (tag_set
->flags
& BLK_MQ_F_BLOCKING
)
2495 hw_ctx_size
+= sizeof(struct srcu_struct
);
2500 static int blk_mq_init_hctx(struct request_queue
*q
,
2501 struct blk_mq_tag_set
*set
,
2502 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
2504 hctx
->queue_num
= hctx_idx
;
2506 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
2507 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
2508 &hctx
->cpuhp_online
);
2509 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD
, &hctx
->cpuhp_dead
);
2511 hctx
->tags
= set
->tags
[hctx_idx
];
2513 if (set
->ops
->init_hctx
&&
2514 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
2515 goto unregister_cpu_notifier
;
2517 if (blk_mq_init_request(set
, hctx
->fq
->flush_rq
, hctx_idx
,
2523 if (set
->ops
->exit_hctx
)
2524 set
->ops
->exit_hctx(hctx
, hctx_idx
);
2525 unregister_cpu_notifier
:
2526 blk_mq_remove_cpuhp(hctx
);
2530 static struct blk_mq_hw_ctx
*
2531 blk_mq_alloc_hctx(struct request_queue
*q
, struct blk_mq_tag_set
*set
,
2534 struct blk_mq_hw_ctx
*hctx
;
2535 gfp_t gfp
= GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
;
2537 hctx
= kzalloc_node(blk_mq_hw_ctx_size(set
), gfp
, node
);
2539 goto fail_alloc_hctx
;
2541 if (!zalloc_cpumask_var_node(&hctx
->cpumask
, gfp
, node
))
2544 atomic_set(&hctx
->nr_active
, 0);
2545 if (node
== NUMA_NO_NODE
)
2546 node
= set
->numa_node
;
2547 hctx
->numa_node
= node
;
2549 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
2550 spin_lock_init(&hctx
->lock
);
2551 INIT_LIST_HEAD(&hctx
->dispatch
);
2553 hctx
->flags
= set
->flags
& ~BLK_MQ_F_TAG_SHARED
;
2555 INIT_LIST_HEAD(&hctx
->hctx_list
);
2558 * Allocate space for all possible cpus to avoid allocation at
2561 hctx
->ctxs
= kmalloc_array_node(nr_cpu_ids
, sizeof(void *),
2566 if (sbitmap_init_node(&hctx
->ctx_map
, nr_cpu_ids
, ilog2(8),
2571 spin_lock_init(&hctx
->dispatch_wait_lock
);
2572 init_waitqueue_func_entry(&hctx
->dispatch_wait
, blk_mq_dispatch_wake
);
2573 INIT_LIST_HEAD(&hctx
->dispatch_wait
.entry
);
2575 hctx
->fq
= blk_alloc_flush_queue(hctx
->numa_node
, set
->cmd_size
, gfp
);
2579 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
2580 init_srcu_struct(hctx
->srcu
);
2581 blk_mq_hctx_kobj_init(hctx
);
2586 sbitmap_free(&hctx
->ctx_map
);
2590 free_cpumask_var(hctx
->cpumask
);
2597 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
2598 unsigned int nr_hw_queues
)
2600 struct blk_mq_tag_set
*set
= q
->tag_set
;
2603 for_each_possible_cpu(i
) {
2604 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
2605 struct blk_mq_hw_ctx
*hctx
;
2609 spin_lock_init(&__ctx
->lock
);
2610 for (k
= HCTX_TYPE_DEFAULT
; k
< HCTX_MAX_TYPES
; k
++)
2611 INIT_LIST_HEAD(&__ctx
->rq_lists
[k
]);
2616 * Set local node, IFF we have more than one hw queue. If
2617 * not, we remain on the home node of the device
2619 for (j
= 0; j
< set
->nr_maps
; j
++) {
2620 hctx
= blk_mq_map_queue_type(q
, j
, i
);
2621 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
2622 hctx
->numa_node
= local_memory_node(cpu_to_node(i
));
2627 static bool __blk_mq_alloc_map_and_request(struct blk_mq_tag_set
*set
,
2632 set
->tags
[hctx_idx
] = blk_mq_alloc_rq_map(set
, hctx_idx
,
2633 set
->queue_depth
, set
->reserved_tags
);
2634 if (!set
->tags
[hctx_idx
])
2637 ret
= blk_mq_alloc_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
,
2642 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2643 set
->tags
[hctx_idx
] = NULL
;
2647 static void blk_mq_free_map_and_requests(struct blk_mq_tag_set
*set
,
2648 unsigned int hctx_idx
)
2650 if (set
->tags
&& set
->tags
[hctx_idx
]) {
2651 blk_mq_free_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
);
2652 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2653 set
->tags
[hctx_idx
] = NULL
;
2657 static void blk_mq_map_swqueue(struct request_queue
*q
)
2659 unsigned int i
, j
, hctx_idx
;
2660 struct blk_mq_hw_ctx
*hctx
;
2661 struct blk_mq_ctx
*ctx
;
2662 struct blk_mq_tag_set
*set
= q
->tag_set
;
2664 queue_for_each_hw_ctx(q
, hctx
, i
) {
2665 cpumask_clear(hctx
->cpumask
);
2667 hctx
->dispatch_from
= NULL
;
2671 * Map software to hardware queues.
2673 * If the cpu isn't present, the cpu is mapped to first hctx.
2675 for_each_possible_cpu(i
) {
2677 ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
2678 for (j
= 0; j
< set
->nr_maps
; j
++) {
2679 if (!set
->map
[j
].nr_queues
) {
2680 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
2681 HCTX_TYPE_DEFAULT
, i
);
2684 hctx_idx
= set
->map
[j
].mq_map
[i
];
2685 /* unmapped hw queue can be remapped after CPU topo changed */
2686 if (!set
->tags
[hctx_idx
] &&
2687 !__blk_mq_alloc_map_and_request(set
, hctx_idx
)) {
2689 * If tags initialization fail for some hctx,
2690 * that hctx won't be brought online. In this
2691 * case, remap the current ctx to hctx[0] which
2692 * is guaranteed to always have tags allocated
2694 set
->map
[j
].mq_map
[i
] = 0;
2697 hctx
= blk_mq_map_queue_type(q
, j
, i
);
2698 ctx
->hctxs
[j
] = hctx
;
2700 * If the CPU is already set in the mask, then we've
2701 * mapped this one already. This can happen if
2702 * devices share queues across queue maps.
2704 if (cpumask_test_cpu(i
, hctx
->cpumask
))
2707 cpumask_set_cpu(i
, hctx
->cpumask
);
2709 ctx
->index_hw
[hctx
->type
] = hctx
->nr_ctx
;
2710 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
2713 * If the nr_ctx type overflows, we have exceeded the
2714 * amount of sw queues we can support.
2716 BUG_ON(!hctx
->nr_ctx
);
2719 for (; j
< HCTX_MAX_TYPES
; j
++)
2720 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
2721 HCTX_TYPE_DEFAULT
, i
);
2724 queue_for_each_hw_ctx(q
, hctx
, i
) {
2726 * If no software queues are mapped to this hardware queue,
2727 * disable it and free the request entries.
2729 if (!hctx
->nr_ctx
) {
2730 /* Never unmap queue 0. We need it as a
2731 * fallback in case of a new remap fails
2734 if (i
&& set
->tags
[i
])
2735 blk_mq_free_map_and_requests(set
, i
);
2741 hctx
->tags
= set
->tags
[i
];
2742 WARN_ON(!hctx
->tags
);
2745 * Set the map size to the number of mapped software queues.
2746 * This is more accurate and more efficient than looping
2747 * over all possibly mapped software queues.
2749 sbitmap_resize(&hctx
->ctx_map
, hctx
->nr_ctx
);
2752 * Initialize batch roundrobin counts
2754 hctx
->next_cpu
= blk_mq_first_mapped_cpu(hctx
);
2755 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
2760 * Caller needs to ensure that we're either frozen/quiesced, or that
2761 * the queue isn't live yet.
2763 static void queue_set_hctx_shared(struct request_queue
*q
, bool shared
)
2765 struct blk_mq_hw_ctx
*hctx
;
2768 queue_for_each_hw_ctx(q
, hctx
, i
) {
2770 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
2772 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2776 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
,
2779 struct request_queue
*q
;
2781 lockdep_assert_held(&set
->tag_list_lock
);
2783 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
2784 blk_mq_freeze_queue(q
);
2785 queue_set_hctx_shared(q
, shared
);
2786 blk_mq_unfreeze_queue(q
);
2790 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
2792 struct blk_mq_tag_set
*set
= q
->tag_set
;
2794 mutex_lock(&set
->tag_list_lock
);
2795 list_del_rcu(&q
->tag_set_list
);
2796 if (list_is_singular(&set
->tag_list
)) {
2797 /* just transitioned to unshared */
2798 set
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2799 /* update existing queue */
2800 blk_mq_update_tag_set_depth(set
, false);
2802 mutex_unlock(&set
->tag_list_lock
);
2803 INIT_LIST_HEAD(&q
->tag_set_list
);
2806 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
2807 struct request_queue
*q
)
2809 mutex_lock(&set
->tag_list_lock
);
2812 * Check to see if we're transitioning to shared (from 1 to 2 queues).
2814 if (!list_empty(&set
->tag_list
) &&
2815 !(set
->flags
& BLK_MQ_F_TAG_SHARED
)) {
2816 set
->flags
|= BLK_MQ_F_TAG_SHARED
;
2817 /* update existing queue */
2818 blk_mq_update_tag_set_depth(set
, true);
2820 if (set
->flags
& BLK_MQ_F_TAG_SHARED
)
2821 queue_set_hctx_shared(q
, true);
2822 list_add_tail_rcu(&q
->tag_set_list
, &set
->tag_list
);
2824 mutex_unlock(&set
->tag_list_lock
);
2827 /* All allocations will be freed in release handler of q->mq_kobj */
2828 static int blk_mq_alloc_ctxs(struct request_queue
*q
)
2830 struct blk_mq_ctxs
*ctxs
;
2833 ctxs
= kzalloc(sizeof(*ctxs
), GFP_KERNEL
);
2837 ctxs
->queue_ctx
= alloc_percpu(struct blk_mq_ctx
);
2838 if (!ctxs
->queue_ctx
)
2841 for_each_possible_cpu(cpu
) {
2842 struct blk_mq_ctx
*ctx
= per_cpu_ptr(ctxs
->queue_ctx
, cpu
);
2846 q
->mq_kobj
= &ctxs
->kobj
;
2847 q
->queue_ctx
= ctxs
->queue_ctx
;
2856 * It is the actual release handler for mq, but we do it from
2857 * request queue's release handler for avoiding use-after-free
2858 * and headache because q->mq_kobj shouldn't have been introduced,
2859 * but we can't group ctx/kctx kobj without it.
2861 void blk_mq_release(struct request_queue
*q
)
2863 struct blk_mq_hw_ctx
*hctx
, *next
;
2866 queue_for_each_hw_ctx(q
, hctx
, i
)
2867 WARN_ON_ONCE(hctx
&& list_empty(&hctx
->hctx_list
));
2869 /* all hctx are in .unused_hctx_list now */
2870 list_for_each_entry_safe(hctx
, next
, &q
->unused_hctx_list
, hctx_list
) {
2871 list_del_init(&hctx
->hctx_list
);
2872 kobject_put(&hctx
->kobj
);
2875 kfree(q
->queue_hw_ctx
);
2878 * release .mq_kobj and sw queue's kobject now because
2879 * both share lifetime with request queue.
2881 blk_mq_sysfs_deinit(q
);
2884 struct request_queue
*blk_mq_init_queue_data(struct blk_mq_tag_set
*set
,
2887 struct request_queue
*uninit_q
, *q
;
2889 uninit_q
= __blk_alloc_queue(set
->numa_node
);
2891 return ERR_PTR(-ENOMEM
);
2892 uninit_q
->queuedata
= queuedata
;
2895 * Initialize the queue without an elevator. device_add_disk() will do
2896 * the initialization.
2898 q
= blk_mq_init_allocated_queue(set
, uninit_q
, false);
2900 blk_cleanup_queue(uninit_q
);
2904 EXPORT_SYMBOL_GPL(blk_mq_init_queue_data
);
2906 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
2908 return blk_mq_init_queue_data(set
, NULL
);
2910 EXPORT_SYMBOL(blk_mq_init_queue
);
2913 * Helper for setting up a queue with mq ops, given queue depth, and
2914 * the passed in mq ops flags.
2916 struct request_queue
*blk_mq_init_sq_queue(struct blk_mq_tag_set
*set
,
2917 const struct blk_mq_ops
*ops
,
2918 unsigned int queue_depth
,
2919 unsigned int set_flags
)
2921 struct request_queue
*q
;
2924 memset(set
, 0, sizeof(*set
));
2926 set
->nr_hw_queues
= 1;
2928 set
->queue_depth
= queue_depth
;
2929 set
->numa_node
= NUMA_NO_NODE
;
2930 set
->flags
= set_flags
;
2932 ret
= blk_mq_alloc_tag_set(set
);
2934 return ERR_PTR(ret
);
2936 q
= blk_mq_init_queue(set
);
2938 blk_mq_free_tag_set(set
);
2944 EXPORT_SYMBOL(blk_mq_init_sq_queue
);
2946 static struct blk_mq_hw_ctx
*blk_mq_alloc_and_init_hctx(
2947 struct blk_mq_tag_set
*set
, struct request_queue
*q
,
2948 int hctx_idx
, int node
)
2950 struct blk_mq_hw_ctx
*hctx
= NULL
, *tmp
;
2952 /* reuse dead hctx first */
2953 spin_lock(&q
->unused_hctx_lock
);
2954 list_for_each_entry(tmp
, &q
->unused_hctx_list
, hctx_list
) {
2955 if (tmp
->numa_node
== node
) {
2961 list_del_init(&hctx
->hctx_list
);
2962 spin_unlock(&q
->unused_hctx_lock
);
2965 hctx
= blk_mq_alloc_hctx(q
, set
, node
);
2969 if (blk_mq_init_hctx(q
, set
, hctx
, hctx_idx
))
2975 kobject_put(&hctx
->kobj
);
2980 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set
*set
,
2981 struct request_queue
*q
)
2984 struct blk_mq_hw_ctx
**hctxs
= q
->queue_hw_ctx
;
2986 if (q
->nr_hw_queues
< set
->nr_hw_queues
) {
2987 struct blk_mq_hw_ctx
**new_hctxs
;
2989 new_hctxs
= kcalloc_node(set
->nr_hw_queues
,
2990 sizeof(*new_hctxs
), GFP_KERNEL
,
2995 memcpy(new_hctxs
, hctxs
, q
->nr_hw_queues
*
2997 q
->queue_hw_ctx
= new_hctxs
;
3002 /* protect against switching io scheduler */
3003 mutex_lock(&q
->sysfs_lock
);
3004 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
3006 struct blk_mq_hw_ctx
*hctx
;
3008 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], i
);
3010 * If the hw queue has been mapped to another numa node,
3011 * we need to realloc the hctx. If allocation fails, fallback
3012 * to use the previous one.
3014 if (hctxs
[i
] && (hctxs
[i
]->numa_node
== node
))
3017 hctx
= blk_mq_alloc_and_init_hctx(set
, q
, i
, node
);
3020 blk_mq_exit_hctx(q
, set
, hctxs
[i
], i
);
3024 pr_warn("Allocate new hctx on node %d fails,\
3025 fallback to previous one on node %d\n",
3026 node
, hctxs
[i
]->numa_node
);
3032 * Increasing nr_hw_queues fails. Free the newly allocated
3033 * hctxs and keep the previous q->nr_hw_queues.
3035 if (i
!= set
->nr_hw_queues
) {
3036 j
= q
->nr_hw_queues
;
3040 end
= q
->nr_hw_queues
;
3041 q
->nr_hw_queues
= set
->nr_hw_queues
;
3044 for (; j
< end
; j
++) {
3045 struct blk_mq_hw_ctx
*hctx
= hctxs
[j
];
3049 blk_mq_free_map_and_requests(set
, j
);
3050 blk_mq_exit_hctx(q
, set
, hctx
, j
);
3054 mutex_unlock(&q
->sysfs_lock
);
3057 struct request_queue
*blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
3058 struct request_queue
*q
,
3061 /* mark the queue as mq asap */
3062 q
->mq_ops
= set
->ops
;
3064 q
->poll_cb
= blk_stat_alloc_callback(blk_mq_poll_stats_fn
,
3065 blk_mq_poll_stats_bkt
,
3066 BLK_MQ_POLL_STATS_BKTS
, q
);
3070 if (blk_mq_alloc_ctxs(q
))
3073 /* init q->mq_kobj and sw queues' kobjects */
3074 blk_mq_sysfs_init(q
);
3076 INIT_LIST_HEAD(&q
->unused_hctx_list
);
3077 spin_lock_init(&q
->unused_hctx_lock
);
3079 blk_mq_realloc_hw_ctxs(set
, q
);
3080 if (!q
->nr_hw_queues
)
3083 INIT_WORK(&q
->timeout_work
, blk_mq_timeout_work
);
3084 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
3088 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
3089 if (set
->nr_maps
> HCTX_TYPE_POLL
&&
3090 set
->map
[HCTX_TYPE_POLL
].nr_queues
)
3091 blk_queue_flag_set(QUEUE_FLAG_POLL
, q
);
3093 q
->sg_reserved_size
= INT_MAX
;
3095 INIT_DELAYED_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
3096 INIT_LIST_HEAD(&q
->requeue_list
);
3097 spin_lock_init(&q
->requeue_lock
);
3099 q
->nr_requests
= set
->queue_depth
;
3102 * Default to classic polling
3104 q
->poll_nsec
= BLK_MQ_POLL_CLASSIC
;
3106 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
3107 blk_mq_add_queue_tag_set(set
, q
);
3108 blk_mq_map_swqueue(q
);
3111 elevator_init_mq(q
);
3116 kfree(q
->queue_hw_ctx
);
3117 q
->nr_hw_queues
= 0;
3118 blk_mq_sysfs_deinit(q
);
3120 blk_stat_free_callback(q
->poll_cb
);
3124 return ERR_PTR(-ENOMEM
);
3126 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
3128 /* tags can _not_ be used after returning from blk_mq_exit_queue */
3129 void blk_mq_exit_queue(struct request_queue
*q
)
3131 struct blk_mq_tag_set
*set
= q
->tag_set
;
3133 blk_mq_del_queue_tag_set(q
);
3134 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
3137 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
3141 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
3142 if (!__blk_mq_alloc_map_and_request(set
, i
))
3149 blk_mq_free_map_and_requests(set
, i
);
3155 * Allocate the request maps associated with this tag_set. Note that this
3156 * may reduce the depth asked for, if memory is tight. set->queue_depth
3157 * will be updated to reflect the allocated depth.
3159 static int blk_mq_alloc_map_and_requests(struct blk_mq_tag_set
*set
)
3164 depth
= set
->queue_depth
;
3166 err
= __blk_mq_alloc_rq_maps(set
);
3170 set
->queue_depth
>>= 1;
3171 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
3175 } while (set
->queue_depth
);
3177 if (!set
->queue_depth
|| err
) {
3178 pr_err("blk-mq: failed to allocate request map\n");
3182 if (depth
!= set
->queue_depth
)
3183 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
3184 depth
, set
->queue_depth
);
3189 static int blk_mq_update_queue_map(struct blk_mq_tag_set
*set
)
3192 * blk_mq_map_queues() and multiple .map_queues() implementations
3193 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
3194 * number of hardware queues.
3196 if (set
->nr_maps
== 1)
3197 set
->map
[HCTX_TYPE_DEFAULT
].nr_queues
= set
->nr_hw_queues
;
3199 if (set
->ops
->map_queues
&& !is_kdump_kernel()) {
3203 * transport .map_queues is usually done in the following
3206 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
3207 * mask = get_cpu_mask(queue)
3208 * for_each_cpu(cpu, mask)
3209 * set->map[x].mq_map[cpu] = queue;
3212 * When we need to remap, the table has to be cleared for
3213 * killing stale mapping since one CPU may not be mapped
3216 for (i
= 0; i
< set
->nr_maps
; i
++)
3217 blk_mq_clear_mq_map(&set
->map
[i
]);
3219 return set
->ops
->map_queues(set
);
3221 BUG_ON(set
->nr_maps
> 1);
3222 return blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
3226 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set
*set
,
3227 int cur_nr_hw_queues
, int new_nr_hw_queues
)
3229 struct blk_mq_tags
**new_tags
;
3231 if (cur_nr_hw_queues
>= new_nr_hw_queues
)
3234 new_tags
= kcalloc_node(new_nr_hw_queues
, sizeof(struct blk_mq_tags
*),
3235 GFP_KERNEL
, set
->numa_node
);
3240 memcpy(new_tags
, set
->tags
, cur_nr_hw_queues
*
3241 sizeof(*set
->tags
));
3243 set
->tags
= new_tags
;
3244 set
->nr_hw_queues
= new_nr_hw_queues
;
3250 * Alloc a tag set to be associated with one or more request queues.
3251 * May fail with EINVAL for various error conditions. May adjust the
3252 * requested depth down, if it's too large. In that case, the set
3253 * value will be stored in set->queue_depth.
3255 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
3259 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
3261 if (!set
->nr_hw_queues
)
3263 if (!set
->queue_depth
)
3265 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
3268 if (!set
->ops
->queue_rq
)
3271 if (!set
->ops
->get_budget
^ !set
->ops
->put_budget
)
3274 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
3275 pr_info("blk-mq: reduced tag depth to %u\n",
3277 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
3282 else if (set
->nr_maps
> HCTX_MAX_TYPES
)
3286 * If a crashdump is active, then we are potentially in a very
3287 * memory constrained environment. Limit us to 1 queue and
3288 * 64 tags to prevent using too much memory.
3290 if (is_kdump_kernel()) {
3291 set
->nr_hw_queues
= 1;
3293 set
->queue_depth
= min(64U, set
->queue_depth
);
3296 * There is no use for more h/w queues than cpus if we just have
3299 if (set
->nr_maps
== 1 && set
->nr_hw_queues
> nr_cpu_ids
)
3300 set
->nr_hw_queues
= nr_cpu_ids
;
3302 if (blk_mq_realloc_tag_set_tags(set
, 0, set
->nr_hw_queues
) < 0)
3306 for (i
= 0; i
< set
->nr_maps
; i
++) {
3307 set
->map
[i
].mq_map
= kcalloc_node(nr_cpu_ids
,
3308 sizeof(set
->map
[i
].mq_map
[0]),
3309 GFP_KERNEL
, set
->numa_node
);
3310 if (!set
->map
[i
].mq_map
)
3311 goto out_free_mq_map
;
3312 set
->map
[i
].nr_queues
= is_kdump_kernel() ? 1 : set
->nr_hw_queues
;
3315 ret
= blk_mq_update_queue_map(set
);
3317 goto out_free_mq_map
;
3319 ret
= blk_mq_alloc_map_and_requests(set
);
3321 goto out_free_mq_map
;
3323 mutex_init(&set
->tag_list_lock
);
3324 INIT_LIST_HEAD(&set
->tag_list
);
3329 for (i
= 0; i
< set
->nr_maps
; i
++) {
3330 kfree(set
->map
[i
].mq_map
);
3331 set
->map
[i
].mq_map
= NULL
;
3337 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
3339 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
3343 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
3344 blk_mq_free_map_and_requests(set
, i
);
3346 for (j
= 0; j
< set
->nr_maps
; j
++) {
3347 kfree(set
->map
[j
].mq_map
);
3348 set
->map
[j
].mq_map
= NULL
;
3354 EXPORT_SYMBOL(blk_mq_free_tag_set
);
3356 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
3358 struct blk_mq_tag_set
*set
= q
->tag_set
;
3359 struct blk_mq_hw_ctx
*hctx
;
3365 if (q
->nr_requests
== nr
)
3368 blk_mq_freeze_queue(q
);
3369 blk_mq_quiesce_queue(q
);
3372 queue_for_each_hw_ctx(q
, hctx
, i
) {
3376 * If we're using an MQ scheduler, just update the scheduler
3377 * queue depth. This is similar to what the old code would do.
3379 if (!hctx
->sched_tags
) {
3380 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->tags
, nr
,
3383 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->sched_tags
,
3388 if (q
->elevator
&& q
->elevator
->type
->ops
.depth_updated
)
3389 q
->elevator
->type
->ops
.depth_updated(hctx
);
3393 q
->nr_requests
= nr
;
3395 blk_mq_unquiesce_queue(q
);
3396 blk_mq_unfreeze_queue(q
);
3402 * request_queue and elevator_type pair.
3403 * It is just used by __blk_mq_update_nr_hw_queues to cache
3404 * the elevator_type associated with a request_queue.
3406 struct blk_mq_qe_pair
{
3407 struct list_head node
;
3408 struct request_queue
*q
;
3409 struct elevator_type
*type
;
3413 * Cache the elevator_type in qe pair list and switch the
3414 * io scheduler to 'none'
3416 static bool blk_mq_elv_switch_none(struct list_head
*head
,
3417 struct request_queue
*q
)
3419 struct blk_mq_qe_pair
*qe
;
3424 qe
= kmalloc(sizeof(*qe
), GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
);
3428 INIT_LIST_HEAD(&qe
->node
);
3430 qe
->type
= q
->elevator
->type
;
3431 list_add(&qe
->node
, head
);
3433 mutex_lock(&q
->sysfs_lock
);
3435 * After elevator_switch_mq, the previous elevator_queue will be
3436 * released by elevator_release. The reference of the io scheduler
3437 * module get by elevator_get will also be put. So we need to get
3438 * a reference of the io scheduler module here to prevent it to be
3441 __module_get(qe
->type
->elevator_owner
);
3442 elevator_switch_mq(q
, NULL
);
3443 mutex_unlock(&q
->sysfs_lock
);
3448 static void blk_mq_elv_switch_back(struct list_head
*head
,
3449 struct request_queue
*q
)
3451 struct blk_mq_qe_pair
*qe
;
3452 struct elevator_type
*t
= NULL
;
3454 list_for_each_entry(qe
, head
, node
)
3463 list_del(&qe
->node
);
3466 mutex_lock(&q
->sysfs_lock
);
3467 elevator_switch_mq(q
, t
);
3468 mutex_unlock(&q
->sysfs_lock
);
3471 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
,
3474 struct request_queue
*q
;
3476 int prev_nr_hw_queues
;
3478 lockdep_assert_held(&set
->tag_list_lock
);
3480 if (set
->nr_maps
== 1 && nr_hw_queues
> nr_cpu_ids
)
3481 nr_hw_queues
= nr_cpu_ids
;
3482 if (nr_hw_queues
< 1)
3484 if (set
->nr_maps
== 1 && nr_hw_queues
== set
->nr_hw_queues
)
3487 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3488 blk_mq_freeze_queue(q
);
3490 * Switch IO scheduler to 'none', cleaning up the data associated
3491 * with the previous scheduler. We will switch back once we are done
3492 * updating the new sw to hw queue mappings.
3494 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3495 if (!blk_mq_elv_switch_none(&head
, q
))
3498 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3499 blk_mq_debugfs_unregister_hctxs(q
);
3500 blk_mq_sysfs_unregister(q
);
3503 prev_nr_hw_queues
= set
->nr_hw_queues
;
3504 if (blk_mq_realloc_tag_set_tags(set
, set
->nr_hw_queues
, nr_hw_queues
) <
3508 set
->nr_hw_queues
= nr_hw_queues
;
3510 blk_mq_update_queue_map(set
);
3511 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3512 blk_mq_realloc_hw_ctxs(set
, q
);
3513 if (q
->nr_hw_queues
!= set
->nr_hw_queues
) {
3514 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
3515 nr_hw_queues
, prev_nr_hw_queues
);
3516 set
->nr_hw_queues
= prev_nr_hw_queues
;
3517 blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
3520 blk_mq_map_swqueue(q
);
3524 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3525 blk_mq_sysfs_register(q
);
3526 blk_mq_debugfs_register_hctxs(q
);
3530 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3531 blk_mq_elv_switch_back(&head
, q
);
3533 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
3534 blk_mq_unfreeze_queue(q
);
3537 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
, int nr_hw_queues
)
3539 mutex_lock(&set
->tag_list_lock
);
3540 __blk_mq_update_nr_hw_queues(set
, nr_hw_queues
);
3541 mutex_unlock(&set
->tag_list_lock
);
3543 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues
);
3545 /* Enable polling stats and return whether they were already enabled. */
3546 static bool blk_poll_stats_enable(struct request_queue
*q
)
3548 if (test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
3549 blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS
, q
))
3551 blk_stat_add_callback(q
, q
->poll_cb
);
3555 static void blk_mq_poll_stats_start(struct request_queue
*q
)
3558 * We don't arm the callback if polling stats are not enabled or the
3559 * callback is already active.
3561 if (!test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
3562 blk_stat_is_active(q
->poll_cb
))
3565 blk_stat_activate_msecs(q
->poll_cb
, 100);
3568 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
)
3570 struct request_queue
*q
= cb
->data
;
3573 for (bucket
= 0; bucket
< BLK_MQ_POLL_STATS_BKTS
; bucket
++) {
3574 if (cb
->stat
[bucket
].nr_samples
)
3575 q
->poll_stat
[bucket
] = cb
->stat
[bucket
];
3579 static unsigned long blk_mq_poll_nsecs(struct request_queue
*q
,
3582 unsigned long ret
= 0;
3586 * If stats collection isn't on, don't sleep but turn it on for
3589 if (!blk_poll_stats_enable(q
))
3593 * As an optimistic guess, use half of the mean service time
3594 * for this type of request. We can (and should) make this smarter.
3595 * For instance, if the completion latencies are tight, we can
3596 * get closer than just half the mean. This is especially
3597 * important on devices where the completion latencies are longer
3598 * than ~10 usec. We do use the stats for the relevant IO size
3599 * if available which does lead to better estimates.
3601 bucket
= blk_mq_poll_stats_bkt(rq
);
3605 if (q
->poll_stat
[bucket
].nr_samples
)
3606 ret
= (q
->poll_stat
[bucket
].mean
+ 1) / 2;
3611 static bool blk_mq_poll_hybrid_sleep(struct request_queue
*q
,
3614 struct hrtimer_sleeper hs
;
3615 enum hrtimer_mode mode
;
3619 if (rq
->rq_flags
& RQF_MQ_POLL_SLEPT
)
3623 * If we get here, hybrid polling is enabled. Hence poll_nsec can be:
3625 * 0: use half of prev avg
3626 * >0: use this specific value
3628 if (q
->poll_nsec
> 0)
3629 nsecs
= q
->poll_nsec
;
3631 nsecs
= blk_mq_poll_nsecs(q
, rq
);
3636 rq
->rq_flags
|= RQF_MQ_POLL_SLEPT
;
3639 * This will be replaced with the stats tracking code, using
3640 * 'avg_completion_time / 2' as the pre-sleep target.
3644 mode
= HRTIMER_MODE_REL
;
3645 hrtimer_init_sleeper_on_stack(&hs
, CLOCK_MONOTONIC
, mode
);
3646 hrtimer_set_expires(&hs
.timer
, kt
);
3649 if (blk_mq_rq_state(rq
) == MQ_RQ_COMPLETE
)
3651 set_current_state(TASK_UNINTERRUPTIBLE
);
3652 hrtimer_sleeper_start_expires(&hs
, mode
);
3655 hrtimer_cancel(&hs
.timer
);
3656 mode
= HRTIMER_MODE_ABS
;
3657 } while (hs
.task
&& !signal_pending(current
));
3659 __set_current_state(TASK_RUNNING
);
3660 destroy_hrtimer_on_stack(&hs
.timer
);
3664 static bool blk_mq_poll_hybrid(struct request_queue
*q
,
3665 struct blk_mq_hw_ctx
*hctx
, blk_qc_t cookie
)
3669 if (q
->poll_nsec
== BLK_MQ_POLL_CLASSIC
)
3672 if (!blk_qc_t_is_internal(cookie
))
3673 rq
= blk_mq_tag_to_rq(hctx
->tags
, blk_qc_t_to_tag(cookie
));
3675 rq
= blk_mq_tag_to_rq(hctx
->sched_tags
, blk_qc_t_to_tag(cookie
));
3677 * With scheduling, if the request has completed, we'll
3678 * get a NULL return here, as we clear the sched tag when
3679 * that happens. The request still remains valid, like always,
3680 * so we should be safe with just the NULL check.
3686 return blk_mq_poll_hybrid_sleep(q
, rq
);
3690 * blk_poll - poll for IO completions
3692 * @cookie: cookie passed back at IO submission time
3693 * @spin: whether to spin for completions
3696 * Poll for completions on the passed in queue. Returns number of
3697 * completed entries found. If @spin is true, then blk_poll will continue
3698 * looping until at least one completion is found, unless the task is
3699 * otherwise marked running (or we need to reschedule).
3701 int blk_poll(struct request_queue
*q
, blk_qc_t cookie
, bool spin
)
3703 struct blk_mq_hw_ctx
*hctx
;
3706 if (!blk_qc_t_valid(cookie
) ||
3707 !test_bit(QUEUE_FLAG_POLL
, &q
->queue_flags
))
3711 blk_flush_plug_list(current
->plug
, false);
3713 hctx
= q
->queue_hw_ctx
[blk_qc_t_to_queue_num(cookie
)];
3716 * If we sleep, have the caller restart the poll loop to reset
3717 * the state. Like for the other success return cases, the
3718 * caller is responsible for checking if the IO completed. If
3719 * the IO isn't complete, we'll get called again and will go
3720 * straight to the busy poll loop.
3722 if (blk_mq_poll_hybrid(q
, hctx
, cookie
))
3725 hctx
->poll_considered
++;
3727 state
= current
->state
;
3731 hctx
->poll_invoked
++;
3733 ret
= q
->mq_ops
->poll(hctx
);
3735 hctx
->poll_success
++;
3736 __set_current_state(TASK_RUNNING
);
3740 if (signal_pending_state(state
, current
))
3741 __set_current_state(TASK_RUNNING
);
3743 if (current
->state
== TASK_RUNNING
)
3745 if (ret
< 0 || !spin
)
3748 } while (!need_resched());
3750 __set_current_state(TASK_RUNNING
);
3753 EXPORT_SYMBOL_GPL(blk_poll
);
3755 unsigned int blk_mq_rq_cpu(struct request
*rq
)
3757 return rq
->mq_ctx
->cpu
;
3759 EXPORT_SYMBOL(blk_mq_rq_cpu
);
3761 static int __init
blk_mq_init(void)
3763 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD
, "block/mq:dead", NULL
,
3764 blk_mq_hctx_notify_dead
);
3765 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE
, "block/mq:online",
3766 blk_mq_hctx_notify_online
,
3767 blk_mq_hctx_notify_offline
);
3770 subsys_initcall(blk_mq_init
);