1 // SPDX-License-Identifier: GPL-2.0
3 * Block multiqueue core code
5 * Copyright (C) 2013-2014 Jens Axboe
6 * Copyright (C) 2013-2014 Christoph Hellwig
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/backing-dev.h>
11 #include <linux/bio.h>
12 #include <linux/blkdev.h>
13 #include <linux/blk-integrity.h>
14 #include <linux/kmemleak.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/workqueue.h>
19 #include <linux/smp.h>
20 #include <linux/interrupt.h>
21 #include <linux/llist.h>
22 #include <linux/cpu.h>
23 #include <linux/cache.h>
24 #include <linux/sched/sysctl.h>
25 #include <linux/sched/topology.h>
26 #include <linux/sched/signal.h>
27 #include <linux/delay.h>
28 #include <linux/crash_dump.h>
29 #include <linux/prefetch.h>
30 #include <linux/blk-crypto.h>
32 #include <trace/events/block.h>
34 #include <linux/blk-mq.h>
35 #include <linux/t10-pi.h>
38 #include "blk-mq-debugfs.h"
39 #include "blk-mq-tag.h"
42 #include "blk-mq-sched.h"
43 #include "blk-rq-qos.h"
45 static DEFINE_PER_CPU(struct llist_head
, blk_cpu_done
);
47 static void blk_mq_poll_stats_start(struct request_queue
*q
);
48 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
);
50 static int blk_mq_poll_stats_bkt(const struct request
*rq
)
52 int ddir
, sectors
, bucket
;
54 ddir
= rq_data_dir(rq
);
55 sectors
= blk_rq_stats_sectors(rq
);
57 bucket
= ddir
+ 2 * ilog2(sectors
);
61 else if (bucket
>= BLK_MQ_POLL_STATS_BKTS
)
62 return ddir
+ BLK_MQ_POLL_STATS_BKTS
- 2;
67 #define BLK_QC_T_SHIFT 16
68 #define BLK_QC_T_INTERNAL (1U << 31)
70 static inline struct blk_mq_hw_ctx
*blk_qc_to_hctx(struct request_queue
*q
,
73 return q
->queue_hw_ctx
[(qc
& ~BLK_QC_T_INTERNAL
) >> BLK_QC_T_SHIFT
];
76 static inline struct request
*blk_qc_to_rq(struct blk_mq_hw_ctx
*hctx
,
79 unsigned int tag
= qc
& ((1U << BLK_QC_T_SHIFT
) - 1);
81 if (qc
& BLK_QC_T_INTERNAL
)
82 return blk_mq_tag_to_rq(hctx
->sched_tags
, tag
);
83 return blk_mq_tag_to_rq(hctx
->tags
, tag
);
86 static inline blk_qc_t
blk_rq_to_qc(struct request
*rq
)
88 return (rq
->mq_hctx
->queue_num
<< BLK_QC_T_SHIFT
) |
90 rq
->tag
: (rq
->internal_tag
| BLK_QC_T_INTERNAL
));
94 * Check if any of the ctx, dispatch list or elevator
95 * have pending work in this hardware queue.
97 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
99 return !list_empty_careful(&hctx
->dispatch
) ||
100 sbitmap_any_bit_set(&hctx
->ctx_map
) ||
101 blk_mq_sched_has_work(hctx
);
105 * Mark this ctx as having pending work in this hardware queue
107 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
108 struct blk_mq_ctx
*ctx
)
110 const int bit
= ctx
->index_hw
[hctx
->type
];
112 if (!sbitmap_test_bit(&hctx
->ctx_map
, bit
))
113 sbitmap_set_bit(&hctx
->ctx_map
, bit
);
116 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
117 struct blk_mq_ctx
*ctx
)
119 const int bit
= ctx
->index_hw
[hctx
->type
];
121 sbitmap_clear_bit(&hctx
->ctx_map
, bit
);
125 struct block_device
*part
;
126 unsigned int inflight
[2];
129 static bool blk_mq_check_inflight(struct blk_mq_hw_ctx
*hctx
,
130 struct request
*rq
, void *priv
,
133 struct mq_inflight
*mi
= priv
;
135 if ((!mi
->part
->bd_partno
|| rq
->part
== mi
->part
) &&
136 blk_mq_rq_state(rq
) == MQ_RQ_IN_FLIGHT
)
137 mi
->inflight
[rq_data_dir(rq
)]++;
142 unsigned int blk_mq_in_flight(struct request_queue
*q
,
143 struct block_device
*part
)
145 struct mq_inflight mi
= { .part
= part
};
147 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
149 return mi
.inflight
[0] + mi
.inflight
[1];
152 void blk_mq_in_flight_rw(struct request_queue
*q
, struct block_device
*part
,
153 unsigned int inflight
[2])
155 struct mq_inflight mi
= { .part
= part
};
157 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
158 inflight
[0] = mi
.inflight
[0];
159 inflight
[1] = mi
.inflight
[1];
162 void blk_freeze_queue_start(struct request_queue
*q
)
164 mutex_lock(&q
->mq_freeze_lock
);
165 if (++q
->mq_freeze_depth
== 1) {
166 percpu_ref_kill(&q
->q_usage_counter
);
167 mutex_unlock(&q
->mq_freeze_lock
);
169 blk_mq_run_hw_queues(q
, false);
171 mutex_unlock(&q
->mq_freeze_lock
);
174 EXPORT_SYMBOL_GPL(blk_freeze_queue_start
);
176 void blk_mq_freeze_queue_wait(struct request_queue
*q
)
178 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->q_usage_counter
));
180 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait
);
182 int blk_mq_freeze_queue_wait_timeout(struct request_queue
*q
,
183 unsigned long timeout
)
185 return wait_event_timeout(q
->mq_freeze_wq
,
186 percpu_ref_is_zero(&q
->q_usage_counter
),
189 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout
);
192 * Guarantee no request is in use, so we can change any data structure of
193 * the queue afterward.
195 void blk_freeze_queue(struct request_queue
*q
)
198 * In the !blk_mq case we are only calling this to kill the
199 * q_usage_counter, otherwise this increases the freeze depth
200 * and waits for it to return to zero. For this reason there is
201 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
202 * exported to drivers as the only user for unfreeze is blk_mq.
204 blk_freeze_queue_start(q
);
205 blk_mq_freeze_queue_wait(q
);
208 void blk_mq_freeze_queue(struct request_queue
*q
)
211 * ...just an alias to keep freeze and unfreeze actions balanced
212 * in the blk_mq_* namespace
216 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
218 void __blk_mq_unfreeze_queue(struct request_queue
*q
, bool force_atomic
)
220 mutex_lock(&q
->mq_freeze_lock
);
222 q
->q_usage_counter
.data
->force_atomic
= true;
223 q
->mq_freeze_depth
--;
224 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
225 if (!q
->mq_freeze_depth
) {
226 percpu_ref_resurrect(&q
->q_usage_counter
);
227 wake_up_all(&q
->mq_freeze_wq
);
229 mutex_unlock(&q
->mq_freeze_lock
);
232 void blk_mq_unfreeze_queue(struct request_queue
*q
)
234 __blk_mq_unfreeze_queue(q
, false);
236 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
239 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
240 * mpt3sas driver such that this function can be removed.
242 void blk_mq_quiesce_queue_nowait(struct request_queue
*q
)
246 spin_lock_irqsave(&q
->queue_lock
, flags
);
247 if (!q
->quiesce_depth
++)
248 blk_queue_flag_set(QUEUE_FLAG_QUIESCED
, q
);
249 spin_unlock_irqrestore(&q
->queue_lock
, flags
);
251 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait
);
254 * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
257 * Note: it is driver's responsibility for making sure that quiesce has
260 void blk_mq_wait_quiesce_done(struct request_queue
*q
)
262 struct blk_mq_hw_ctx
*hctx
;
266 queue_for_each_hw_ctx(q
, hctx
, i
) {
267 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
268 synchronize_srcu(hctx
->srcu
);
275 EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done
);
278 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
281 * Note: this function does not prevent that the struct request end_io()
282 * callback function is invoked. Once this function is returned, we make
283 * sure no dispatch can happen until the queue is unquiesced via
284 * blk_mq_unquiesce_queue().
286 void blk_mq_quiesce_queue(struct request_queue
*q
)
288 blk_mq_quiesce_queue_nowait(q
);
289 blk_mq_wait_quiesce_done(q
);
291 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue
);
294 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
297 * This function recovers queue into the state before quiescing
298 * which is done by blk_mq_quiesce_queue.
300 void blk_mq_unquiesce_queue(struct request_queue
*q
)
303 bool run_queue
= false;
305 spin_lock_irqsave(&q
->queue_lock
, flags
);
306 if (WARN_ON_ONCE(q
->quiesce_depth
<= 0)) {
308 } else if (!--q
->quiesce_depth
) {
309 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED
, q
);
312 spin_unlock_irqrestore(&q
->queue_lock
, flags
);
314 /* dispatch requests which are inserted during quiescing */
316 blk_mq_run_hw_queues(q
, true);
318 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue
);
320 void blk_mq_wake_waiters(struct request_queue
*q
)
322 struct blk_mq_hw_ctx
*hctx
;
325 queue_for_each_hw_ctx(q
, hctx
, i
)
326 if (blk_mq_hw_queue_mapped(hctx
))
327 blk_mq_tag_wakeup_all(hctx
->tags
, true);
330 static struct request
*blk_mq_rq_ctx_init(struct blk_mq_alloc_data
*data
,
331 struct blk_mq_tags
*tags
, unsigned int tag
, u64 alloc_time_ns
)
333 struct blk_mq_ctx
*ctx
= data
->ctx
;
334 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
335 struct request_queue
*q
= data
->q
;
336 struct request
*rq
= tags
->static_rqs
[tag
];
341 rq
->cmd_flags
= data
->cmd_flags
;
343 if (data
->flags
& BLK_MQ_REQ_PM
)
344 data
->rq_flags
|= RQF_PM
;
345 if (blk_queue_io_stat(q
))
346 data
->rq_flags
|= RQF_IO_STAT
;
347 rq
->rq_flags
= data
->rq_flags
;
349 if (!(data
->rq_flags
& RQF_ELV
)) {
351 rq
->internal_tag
= BLK_MQ_NO_TAG
;
353 rq
->tag
= BLK_MQ_NO_TAG
;
354 rq
->internal_tag
= tag
;
358 if (blk_mq_need_time_stamp(rq
))
359 rq
->start_time_ns
= ktime_get_ns();
361 rq
->start_time_ns
= 0;
364 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
365 rq
->alloc_time_ns
= alloc_time_ns
;
367 rq
->io_start_time_ns
= 0;
368 rq
->stats_sectors
= 0;
369 rq
->nr_phys_segments
= 0;
370 #if defined(CONFIG_BLK_DEV_INTEGRITY)
371 rq
->nr_integrity_segments
= 0;
374 rq
->end_io_data
= NULL
;
376 blk_crypto_rq_set_defaults(rq
);
377 INIT_LIST_HEAD(&rq
->queuelist
);
378 /* tag was already set */
379 WRITE_ONCE(rq
->deadline
, 0);
380 refcount_set(&rq
->ref
, 1);
382 if (rq
->rq_flags
& RQF_ELV
) {
383 struct elevator_queue
*e
= data
->q
->elevator
;
386 INIT_HLIST_NODE(&rq
->hash
);
387 RB_CLEAR_NODE(&rq
->rb_node
);
389 if (!op_is_flush(data
->cmd_flags
) &&
390 e
->type
->ops
.prepare_request
) {
391 if (e
->type
->icq_cache
)
392 blk_mq_sched_assign_ioc(rq
);
394 e
->type
->ops
.prepare_request(rq
);
395 rq
->rq_flags
|= RQF_ELVPRIV
;
402 static inline struct request
*
403 __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data
*data
,
406 unsigned int tag
, tag_offset
;
407 struct blk_mq_tags
*tags
;
409 unsigned long tag_mask
;
412 tag_mask
= blk_mq_get_tags(data
, data
->nr_tags
, &tag_offset
);
413 if (unlikely(!tag_mask
))
416 tags
= blk_mq_tags_from_data(data
);
417 for (i
= 0; tag_mask
; i
++) {
418 if (!(tag_mask
& (1UL << i
)))
420 tag
= tag_offset
+ i
;
421 prefetch(tags
->static_rqs
[tag
]);
422 tag_mask
&= ~(1UL << i
);
423 rq
= blk_mq_rq_ctx_init(data
, tags
, tag
, alloc_time_ns
);
424 rq_list_add(data
->cached_rq
, rq
);
427 /* caller already holds a reference, add for remainder */
428 percpu_ref_get_many(&data
->q
->q_usage_counter
, nr
- 1);
431 return rq_list_pop(data
->cached_rq
);
434 static struct request
*__blk_mq_alloc_requests(struct blk_mq_alloc_data
*data
)
436 struct request_queue
*q
= data
->q
;
437 u64 alloc_time_ns
= 0;
441 /* alloc_time includes depth and tag waits */
442 if (blk_queue_rq_alloc_time(q
))
443 alloc_time_ns
= ktime_get_ns();
445 if (data
->cmd_flags
& REQ_NOWAIT
)
446 data
->flags
|= BLK_MQ_REQ_NOWAIT
;
449 struct elevator_queue
*e
= q
->elevator
;
451 data
->rq_flags
|= RQF_ELV
;
454 * Flush/passthrough requests are special and go directly to the
455 * dispatch list. Don't include reserved tags in the
456 * limiting, as it isn't useful.
458 if (!op_is_flush(data
->cmd_flags
) &&
459 !blk_op_is_passthrough(data
->cmd_flags
) &&
460 e
->type
->ops
.limit_depth
&&
461 !(data
->flags
& BLK_MQ_REQ_RESERVED
))
462 e
->type
->ops
.limit_depth(data
->cmd_flags
, data
);
466 data
->ctx
= blk_mq_get_ctx(q
);
467 data
->hctx
= blk_mq_map_queue(q
, data
->cmd_flags
, data
->ctx
);
468 if (!(data
->rq_flags
& RQF_ELV
))
469 blk_mq_tag_busy(data
->hctx
);
472 * Try batched alloc if we want more than 1 tag.
474 if (data
->nr_tags
> 1) {
475 rq
= __blk_mq_alloc_requests_batch(data
, alloc_time_ns
);
482 * Waiting allocations only fail because of an inactive hctx. In that
483 * case just retry the hctx assignment and tag allocation as CPU hotplug
484 * should have migrated us to an online CPU by now.
486 tag
= blk_mq_get_tag(data
);
487 if (tag
== BLK_MQ_NO_TAG
) {
488 if (data
->flags
& BLK_MQ_REQ_NOWAIT
)
491 * Give up the CPU and sleep for a random short time to
492 * ensure that thread using a realtime scheduling class
493 * are migrated off the CPU, and thus off the hctx that
500 return blk_mq_rq_ctx_init(data
, blk_mq_tags_from_data(data
), tag
,
504 struct request
*blk_mq_alloc_request(struct request_queue
*q
, unsigned int op
,
505 blk_mq_req_flags_t flags
)
507 struct blk_mq_alloc_data data
= {
516 ret
= blk_queue_enter(q
, flags
);
520 rq
= __blk_mq_alloc_requests(&data
);
524 rq
->__sector
= (sector_t
) -1;
525 rq
->bio
= rq
->biotail
= NULL
;
529 return ERR_PTR(-EWOULDBLOCK
);
531 EXPORT_SYMBOL(blk_mq_alloc_request
);
533 struct request
*blk_mq_alloc_request_hctx(struct request_queue
*q
,
534 unsigned int op
, blk_mq_req_flags_t flags
, unsigned int hctx_idx
)
536 struct blk_mq_alloc_data data
= {
542 u64 alloc_time_ns
= 0;
547 /* alloc_time includes depth and tag waits */
548 if (blk_queue_rq_alloc_time(q
))
549 alloc_time_ns
= ktime_get_ns();
552 * If the tag allocator sleeps we could get an allocation for a
553 * different hardware context. No need to complicate the low level
554 * allocator for this for the rare use case of a command tied to
557 if (WARN_ON_ONCE(!(flags
& (BLK_MQ_REQ_NOWAIT
| BLK_MQ_REQ_RESERVED
))))
558 return ERR_PTR(-EINVAL
);
560 if (hctx_idx
>= q
->nr_hw_queues
)
561 return ERR_PTR(-EIO
);
563 ret
= blk_queue_enter(q
, flags
);
568 * Check if the hardware context is actually mapped to anything.
569 * If not tell the caller that it should skip this queue.
572 data
.hctx
= q
->queue_hw_ctx
[hctx_idx
];
573 if (!blk_mq_hw_queue_mapped(data
.hctx
))
575 cpu
= cpumask_first_and(data
.hctx
->cpumask
, cpu_online_mask
);
576 data
.ctx
= __blk_mq_get_ctx(q
, cpu
);
579 blk_mq_tag_busy(data
.hctx
);
581 data
.rq_flags
|= RQF_ELV
;
584 tag
= blk_mq_get_tag(&data
);
585 if (tag
== BLK_MQ_NO_TAG
)
587 return blk_mq_rq_ctx_init(&data
, blk_mq_tags_from_data(&data
), tag
,
594 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx
);
596 static void __blk_mq_free_request(struct request
*rq
)
598 struct request_queue
*q
= rq
->q
;
599 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
600 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
601 const int sched_tag
= rq
->internal_tag
;
603 blk_crypto_free_request(rq
);
604 blk_pm_mark_last_busy(rq
);
606 if (rq
->tag
!= BLK_MQ_NO_TAG
)
607 blk_mq_put_tag(hctx
->tags
, ctx
, rq
->tag
);
608 if (sched_tag
!= BLK_MQ_NO_TAG
)
609 blk_mq_put_tag(hctx
->sched_tags
, ctx
, sched_tag
);
610 blk_mq_sched_restart(hctx
);
614 void blk_mq_free_request(struct request
*rq
)
616 struct request_queue
*q
= rq
->q
;
617 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
619 if (rq
->rq_flags
& RQF_ELVPRIV
) {
620 struct elevator_queue
*e
= q
->elevator
;
622 if (e
->type
->ops
.finish_request
)
623 e
->type
->ops
.finish_request(rq
);
625 put_io_context(rq
->elv
.icq
->ioc
);
630 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
)
631 __blk_mq_dec_active_requests(hctx
);
633 if (unlikely(laptop_mode
&& !blk_rq_is_passthrough(rq
)))
634 laptop_io_completion(q
->disk
->bdi
);
638 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
639 if (refcount_dec_and_test(&rq
->ref
))
640 __blk_mq_free_request(rq
);
642 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
644 void blk_mq_free_plug_rqs(struct blk_plug
*plug
)
648 while ((rq
= rq_list_pop(&plug
->cached_rq
)) != NULL
)
649 blk_mq_free_request(rq
);
652 static void req_bio_endio(struct request
*rq
, struct bio
*bio
,
653 unsigned int nbytes
, blk_status_t error
)
655 if (unlikely(error
)) {
656 bio
->bi_status
= error
;
657 } else if (req_op(rq
) == REQ_OP_ZONE_APPEND
) {
659 * Partial zone append completions cannot be supported as the
660 * BIO fragments may end up not being written sequentially.
662 if (bio
->bi_iter
.bi_size
!= nbytes
)
663 bio
->bi_status
= BLK_STS_IOERR
;
665 bio
->bi_iter
.bi_sector
= rq
->__sector
;
668 bio_advance(bio
, nbytes
);
670 if (unlikely(rq
->rq_flags
& RQF_QUIET
))
671 bio_set_flag(bio
, BIO_QUIET
);
672 /* don't actually finish bio if it's part of flush sequence */
673 if (bio
->bi_iter
.bi_size
== 0 && !(rq
->rq_flags
& RQF_FLUSH_SEQ
))
677 static void blk_account_io_completion(struct request
*req
, unsigned int bytes
)
679 if (req
->part
&& blk_do_io_stat(req
)) {
680 const int sgrp
= op_stat_group(req_op(req
));
683 part_stat_add(req
->part
, sectors
[sgrp
], bytes
>> 9);
689 * blk_update_request - Complete multiple bytes without completing the request
690 * @req: the request being processed
691 * @error: block status code
692 * @nr_bytes: number of bytes to complete for @req
695 * Ends I/O on a number of bytes attached to @req, but doesn't complete
696 * the request structure even if @req doesn't have leftover.
697 * If @req has leftover, sets it up for the next range of segments.
699 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
700 * %false return from this function.
703 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
704 * except in the consistency check at the end of this function.
707 * %false - this request doesn't have any more data
708 * %true - this request has more data
710 bool blk_update_request(struct request
*req
, blk_status_t error
,
711 unsigned int nr_bytes
)
715 trace_block_rq_complete(req
, error
, nr_bytes
);
720 #ifdef CONFIG_BLK_DEV_INTEGRITY
721 if (blk_integrity_rq(req
) && req_op(req
) == REQ_OP_READ
&&
723 req
->q
->integrity
.profile
->complete_fn(req
, nr_bytes
);
726 if (unlikely(error
&& !blk_rq_is_passthrough(req
) &&
727 !(req
->rq_flags
& RQF_QUIET
)))
728 blk_print_req_error(req
, error
);
730 blk_account_io_completion(req
, nr_bytes
);
734 struct bio
*bio
= req
->bio
;
735 unsigned bio_bytes
= min(bio
->bi_iter
.bi_size
, nr_bytes
);
737 if (bio_bytes
== bio
->bi_iter
.bi_size
)
738 req
->bio
= bio
->bi_next
;
740 /* Completion has already been traced */
741 bio_clear_flag(bio
, BIO_TRACE_COMPLETION
);
742 req_bio_endio(req
, bio
, bio_bytes
, error
);
744 total_bytes
+= bio_bytes
;
745 nr_bytes
-= bio_bytes
;
756 * Reset counters so that the request stacking driver
757 * can find how many bytes remain in the request
764 req
->__data_len
-= total_bytes
;
766 /* update sector only for requests with clear definition of sector */
767 if (!blk_rq_is_passthrough(req
))
768 req
->__sector
+= total_bytes
>> 9;
770 /* mixed attributes always follow the first bio */
771 if (req
->rq_flags
& RQF_MIXED_MERGE
) {
772 req
->cmd_flags
&= ~REQ_FAILFAST_MASK
;
773 req
->cmd_flags
|= req
->bio
->bi_opf
& REQ_FAILFAST_MASK
;
776 if (!(req
->rq_flags
& RQF_SPECIAL_PAYLOAD
)) {
778 * If total number of sectors is less than the first segment
779 * size, something has gone terribly wrong.
781 if (blk_rq_bytes(req
) < blk_rq_cur_bytes(req
)) {
782 blk_dump_rq_flags(req
, "request botched");
783 req
->__data_len
= blk_rq_cur_bytes(req
);
786 /* recalculate the number of segments */
787 req
->nr_phys_segments
= blk_recalc_rq_segments(req
);
792 EXPORT_SYMBOL_GPL(blk_update_request
);
794 static inline void __blk_mq_end_request_acct(struct request
*rq
, u64 now
)
796 if (rq
->rq_flags
& RQF_STATS
) {
797 blk_mq_poll_stats_start(rq
->q
);
798 blk_stat_add(rq
, now
);
801 blk_mq_sched_completed_request(rq
, now
);
802 blk_account_io_done(rq
, now
);
805 inline void __blk_mq_end_request(struct request
*rq
, blk_status_t error
)
807 if (blk_mq_need_time_stamp(rq
))
808 __blk_mq_end_request_acct(rq
, ktime_get_ns());
811 rq_qos_done(rq
->q
, rq
);
812 rq
->end_io(rq
, error
);
814 blk_mq_free_request(rq
);
817 EXPORT_SYMBOL(__blk_mq_end_request
);
819 void blk_mq_end_request(struct request
*rq
, blk_status_t error
)
821 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
823 __blk_mq_end_request(rq
, error
);
825 EXPORT_SYMBOL(blk_mq_end_request
);
827 #define TAG_COMP_BATCH 32
829 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx
*hctx
,
830 int *tag_array
, int nr_tags
)
832 struct request_queue
*q
= hctx
->queue
;
835 * All requests should have been marked as RQF_MQ_INFLIGHT, so
836 * update hctx->nr_active in batch
838 if (hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)
839 __blk_mq_sub_active_requests(hctx
, nr_tags
);
841 blk_mq_put_tags(hctx
->tags
, tag_array
, nr_tags
);
842 percpu_ref_put_many(&q
->q_usage_counter
, nr_tags
);
845 void blk_mq_end_request_batch(struct io_comp_batch
*iob
)
847 int tags
[TAG_COMP_BATCH
], nr_tags
= 0;
848 struct blk_mq_hw_ctx
*cur_hctx
= NULL
;
853 now
= ktime_get_ns();
855 while ((rq
= rq_list_pop(&iob
->req_list
)) != NULL
) {
857 prefetch(rq
->rq_next
);
859 blk_update_request(rq
, BLK_STS_OK
, blk_rq_bytes(rq
));
861 __blk_mq_end_request_acct(rq
, now
);
863 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
864 if (!refcount_dec_and_test(&rq
->ref
))
867 blk_crypto_free_request(rq
);
868 blk_pm_mark_last_busy(rq
);
869 rq_qos_done(rq
->q
, rq
);
871 if (nr_tags
== TAG_COMP_BATCH
|| cur_hctx
!= rq
->mq_hctx
) {
873 blk_mq_flush_tag_batch(cur_hctx
, tags
, nr_tags
);
875 cur_hctx
= rq
->mq_hctx
;
877 tags
[nr_tags
++] = rq
->tag
;
881 blk_mq_flush_tag_batch(cur_hctx
, tags
, nr_tags
);
883 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch
);
885 static void blk_complete_reqs(struct llist_head
*list
)
887 struct llist_node
*entry
= llist_reverse_order(llist_del_all(list
));
888 struct request
*rq
, *next
;
890 llist_for_each_entry_safe(rq
, next
, entry
, ipi_list
)
891 rq
->q
->mq_ops
->complete(rq
);
894 static __latent_entropy
void blk_done_softirq(struct softirq_action
*h
)
896 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done
));
899 static int blk_softirq_cpu_dead(unsigned int cpu
)
901 blk_complete_reqs(&per_cpu(blk_cpu_done
, cpu
));
905 static void __blk_mq_complete_request_remote(void *data
)
907 __raise_softirq_irqoff(BLOCK_SOFTIRQ
);
910 static inline bool blk_mq_complete_need_ipi(struct request
*rq
)
912 int cpu
= raw_smp_processor_id();
914 if (!IS_ENABLED(CONFIG_SMP
) ||
915 !test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
))
918 * With force threaded interrupts enabled, raising softirq from an SMP
919 * function call will always result in waking the ksoftirqd thread.
920 * This is probably worse than completing the request on a different
923 if (force_irqthreads())
926 /* same CPU or cache domain? Complete locally */
927 if (cpu
== rq
->mq_ctx
->cpu
||
928 (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
) &&
929 cpus_share_cache(cpu
, rq
->mq_ctx
->cpu
)))
932 /* don't try to IPI to an offline CPU */
933 return cpu_online(rq
->mq_ctx
->cpu
);
936 static void blk_mq_complete_send_ipi(struct request
*rq
)
938 struct llist_head
*list
;
941 cpu
= rq
->mq_ctx
->cpu
;
942 list
= &per_cpu(blk_cpu_done
, cpu
);
943 if (llist_add(&rq
->ipi_list
, list
)) {
944 INIT_CSD(&rq
->csd
, __blk_mq_complete_request_remote
, rq
);
945 smp_call_function_single_async(cpu
, &rq
->csd
);
949 static void blk_mq_raise_softirq(struct request
*rq
)
951 struct llist_head
*list
;
954 list
= this_cpu_ptr(&blk_cpu_done
);
955 if (llist_add(&rq
->ipi_list
, list
))
956 raise_softirq(BLOCK_SOFTIRQ
);
960 bool blk_mq_complete_request_remote(struct request
*rq
)
962 WRITE_ONCE(rq
->state
, MQ_RQ_COMPLETE
);
965 * For a polled request, always complete locallly, it's pointless
966 * to redirect the completion.
968 if (rq
->cmd_flags
& REQ_POLLED
)
971 if (blk_mq_complete_need_ipi(rq
)) {
972 blk_mq_complete_send_ipi(rq
);
976 if (rq
->q
->nr_hw_queues
== 1) {
977 blk_mq_raise_softirq(rq
);
982 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote
);
985 * blk_mq_complete_request - end I/O on a request
986 * @rq: the request being processed
989 * Complete a request by scheduling the ->complete_rq operation.
991 void blk_mq_complete_request(struct request
*rq
)
993 if (!blk_mq_complete_request_remote(rq
))
994 rq
->q
->mq_ops
->complete(rq
);
996 EXPORT_SYMBOL(blk_mq_complete_request
);
998 static void hctx_unlock(struct blk_mq_hw_ctx
*hctx
, int srcu_idx
)
999 __releases(hctx
->srcu
)
1001 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
))
1004 srcu_read_unlock(hctx
->srcu
, srcu_idx
);
1007 static void hctx_lock(struct blk_mq_hw_ctx
*hctx
, int *srcu_idx
)
1008 __acquires(hctx
->srcu
)
1010 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1011 /* shut up gcc false positive */
1015 *srcu_idx
= srcu_read_lock(hctx
->srcu
);
1019 * blk_mq_start_request - Start processing a request
1020 * @rq: Pointer to request to be started
1022 * Function used by device drivers to notify the block layer that a request
1023 * is going to be processed now, so blk layer can do proper initializations
1024 * such as starting the timeout timer.
1026 void blk_mq_start_request(struct request
*rq
)
1028 struct request_queue
*q
= rq
->q
;
1030 trace_block_rq_issue(rq
);
1032 if (test_bit(QUEUE_FLAG_STATS
, &q
->queue_flags
)) {
1034 #ifdef CONFIG_BLK_CGROUP
1036 start_time
= bio_issue_time(&rq
->bio
->bi_issue
);
1039 start_time
= ktime_get_ns();
1040 rq
->io_start_time_ns
= start_time
;
1041 rq
->stats_sectors
= blk_rq_sectors(rq
);
1042 rq
->rq_flags
|= RQF_STATS
;
1043 rq_qos_issue(q
, rq
);
1046 WARN_ON_ONCE(blk_mq_rq_state(rq
) != MQ_RQ_IDLE
);
1049 WRITE_ONCE(rq
->state
, MQ_RQ_IN_FLIGHT
);
1051 #ifdef CONFIG_BLK_DEV_INTEGRITY
1052 if (blk_integrity_rq(rq
) && req_op(rq
) == REQ_OP_WRITE
)
1053 q
->integrity
.profile
->prepare_fn(rq
);
1055 if (rq
->bio
&& rq
->bio
->bi_opf
& REQ_POLLED
)
1056 WRITE_ONCE(rq
->bio
->bi_cookie
, blk_rq_to_qc(rq
));
1058 EXPORT_SYMBOL(blk_mq_start_request
);
1060 static void __blk_mq_requeue_request(struct request
*rq
)
1062 struct request_queue
*q
= rq
->q
;
1064 blk_mq_put_driver_tag(rq
);
1066 trace_block_rq_requeue(rq
);
1067 rq_qos_requeue(q
, rq
);
1069 if (blk_mq_request_started(rq
)) {
1070 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
1071 rq
->rq_flags
&= ~RQF_TIMED_OUT
;
1075 void blk_mq_requeue_request(struct request
*rq
, bool kick_requeue_list
)
1077 __blk_mq_requeue_request(rq
);
1079 /* this request will be re-inserted to io scheduler queue */
1080 blk_mq_sched_requeue_request(rq
);
1082 blk_mq_add_to_requeue_list(rq
, true, kick_requeue_list
);
1084 EXPORT_SYMBOL(blk_mq_requeue_request
);
1086 static void blk_mq_requeue_work(struct work_struct
*work
)
1088 struct request_queue
*q
=
1089 container_of(work
, struct request_queue
, requeue_work
.work
);
1091 struct request
*rq
, *next
;
1093 spin_lock_irq(&q
->requeue_lock
);
1094 list_splice_init(&q
->requeue_list
, &rq_list
);
1095 spin_unlock_irq(&q
->requeue_lock
);
1097 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
1098 if (!(rq
->rq_flags
& (RQF_SOFTBARRIER
| RQF_DONTPREP
)))
1101 rq
->rq_flags
&= ~RQF_SOFTBARRIER
;
1102 list_del_init(&rq
->queuelist
);
1104 * If RQF_DONTPREP, rq has contained some driver specific
1105 * data, so insert it to hctx dispatch list to avoid any
1108 if (rq
->rq_flags
& RQF_DONTPREP
)
1109 blk_mq_request_bypass_insert(rq
, false, false);
1111 blk_mq_sched_insert_request(rq
, true, false, false);
1114 while (!list_empty(&rq_list
)) {
1115 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
1116 list_del_init(&rq
->queuelist
);
1117 blk_mq_sched_insert_request(rq
, false, false, false);
1120 blk_mq_run_hw_queues(q
, false);
1123 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
,
1124 bool kick_requeue_list
)
1126 struct request_queue
*q
= rq
->q
;
1127 unsigned long flags
;
1130 * We abuse this flag that is otherwise used by the I/O scheduler to
1131 * request head insertion from the workqueue.
1133 BUG_ON(rq
->rq_flags
& RQF_SOFTBARRIER
);
1135 spin_lock_irqsave(&q
->requeue_lock
, flags
);
1137 rq
->rq_flags
|= RQF_SOFTBARRIER
;
1138 list_add(&rq
->queuelist
, &q
->requeue_list
);
1140 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
1142 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
1144 if (kick_requeue_list
)
1145 blk_mq_kick_requeue_list(q
);
1148 void blk_mq_kick_requeue_list(struct request_queue
*q
)
1150 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
, 0);
1152 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
1154 void blk_mq_delay_kick_requeue_list(struct request_queue
*q
,
1155 unsigned long msecs
)
1157 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
,
1158 msecs_to_jiffies(msecs
));
1160 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list
);
1162 static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
1163 void *priv
, bool reserved
)
1166 * If we find a request that isn't idle and the queue matches,
1167 * we know the queue is busy. Return false to stop the iteration.
1169 if (blk_mq_request_started(rq
) && rq
->q
== hctx
->queue
) {
1179 bool blk_mq_queue_inflight(struct request_queue
*q
)
1183 blk_mq_queue_tag_busy_iter(q
, blk_mq_rq_inflight
, &busy
);
1186 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight
);
1188 static void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
1190 req
->rq_flags
|= RQF_TIMED_OUT
;
1191 if (req
->q
->mq_ops
->timeout
) {
1192 enum blk_eh_timer_return ret
;
1194 ret
= req
->q
->mq_ops
->timeout(req
, reserved
);
1195 if (ret
== BLK_EH_DONE
)
1197 WARN_ON_ONCE(ret
!= BLK_EH_RESET_TIMER
);
1203 static bool blk_mq_req_expired(struct request
*rq
, unsigned long *next
)
1205 unsigned long deadline
;
1207 if (blk_mq_rq_state(rq
) != MQ_RQ_IN_FLIGHT
)
1209 if (rq
->rq_flags
& RQF_TIMED_OUT
)
1212 deadline
= READ_ONCE(rq
->deadline
);
1213 if (time_after_eq(jiffies
, deadline
))
1218 else if (time_after(*next
, deadline
))
1223 void blk_mq_put_rq_ref(struct request
*rq
)
1225 if (is_flush_rq(rq
))
1227 else if (refcount_dec_and_test(&rq
->ref
))
1228 __blk_mq_free_request(rq
);
1231 static bool blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
1232 struct request
*rq
, void *priv
, bool reserved
)
1234 unsigned long *next
= priv
;
1237 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1238 * be reallocated underneath the timeout handler's processing, then
1239 * the expire check is reliable. If the request is not expired, then
1240 * it was completed and reallocated as a new request after returning
1241 * from blk_mq_check_expired().
1243 if (blk_mq_req_expired(rq
, next
))
1244 blk_mq_rq_timed_out(rq
, reserved
);
1248 static void blk_mq_timeout_work(struct work_struct
*work
)
1250 struct request_queue
*q
=
1251 container_of(work
, struct request_queue
, timeout_work
);
1252 unsigned long next
= 0;
1253 struct blk_mq_hw_ctx
*hctx
;
1256 /* A deadlock might occur if a request is stuck requiring a
1257 * timeout at the same time a queue freeze is waiting
1258 * completion, since the timeout code would not be able to
1259 * acquire the queue reference here.
1261 * That's why we don't use blk_queue_enter here; instead, we use
1262 * percpu_ref_tryget directly, because we need to be able to
1263 * obtain a reference even in the short window between the queue
1264 * starting to freeze, by dropping the first reference in
1265 * blk_freeze_queue_start, and the moment the last request is
1266 * consumed, marked by the instant q_usage_counter reaches
1269 if (!percpu_ref_tryget(&q
->q_usage_counter
))
1272 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_expired
, &next
);
1275 mod_timer(&q
->timeout
, next
);
1278 * Request timeouts are handled as a forward rolling timer. If
1279 * we end up here it means that no requests are pending and
1280 * also that no request has been pending for a while. Mark
1281 * each hctx as idle.
1283 queue_for_each_hw_ctx(q
, hctx
, i
) {
1284 /* the hctx may be unmapped, so check it here */
1285 if (blk_mq_hw_queue_mapped(hctx
))
1286 blk_mq_tag_idle(hctx
);
1292 struct flush_busy_ctx_data
{
1293 struct blk_mq_hw_ctx
*hctx
;
1294 struct list_head
*list
;
1297 static bool flush_busy_ctx(struct sbitmap
*sb
, unsigned int bitnr
, void *data
)
1299 struct flush_busy_ctx_data
*flush_data
= data
;
1300 struct blk_mq_hw_ctx
*hctx
= flush_data
->hctx
;
1301 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
1302 enum hctx_type type
= hctx
->type
;
1304 spin_lock(&ctx
->lock
);
1305 list_splice_tail_init(&ctx
->rq_lists
[type
], flush_data
->list
);
1306 sbitmap_clear_bit(sb
, bitnr
);
1307 spin_unlock(&ctx
->lock
);
1312 * Process software queues that have been marked busy, splicing them
1313 * to the for-dispatch
1315 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
1317 struct flush_busy_ctx_data data
= {
1322 sbitmap_for_each_set(&hctx
->ctx_map
, flush_busy_ctx
, &data
);
1324 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs
);
1326 struct dispatch_rq_data
{
1327 struct blk_mq_hw_ctx
*hctx
;
1331 static bool dispatch_rq_from_ctx(struct sbitmap
*sb
, unsigned int bitnr
,
1334 struct dispatch_rq_data
*dispatch_data
= data
;
1335 struct blk_mq_hw_ctx
*hctx
= dispatch_data
->hctx
;
1336 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
1337 enum hctx_type type
= hctx
->type
;
1339 spin_lock(&ctx
->lock
);
1340 if (!list_empty(&ctx
->rq_lists
[type
])) {
1341 dispatch_data
->rq
= list_entry_rq(ctx
->rq_lists
[type
].next
);
1342 list_del_init(&dispatch_data
->rq
->queuelist
);
1343 if (list_empty(&ctx
->rq_lists
[type
]))
1344 sbitmap_clear_bit(sb
, bitnr
);
1346 spin_unlock(&ctx
->lock
);
1348 return !dispatch_data
->rq
;
1351 struct request
*blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx
*hctx
,
1352 struct blk_mq_ctx
*start
)
1354 unsigned off
= start
? start
->index_hw
[hctx
->type
] : 0;
1355 struct dispatch_rq_data data
= {
1360 __sbitmap_for_each_set(&hctx
->ctx_map
, off
,
1361 dispatch_rq_from_ctx
, &data
);
1366 static bool __blk_mq_alloc_driver_tag(struct request
*rq
)
1368 struct sbitmap_queue
*bt
= &rq
->mq_hctx
->tags
->bitmap_tags
;
1369 unsigned int tag_offset
= rq
->mq_hctx
->tags
->nr_reserved_tags
;
1372 blk_mq_tag_busy(rq
->mq_hctx
);
1374 if (blk_mq_tag_is_reserved(rq
->mq_hctx
->sched_tags
, rq
->internal_tag
)) {
1375 bt
= &rq
->mq_hctx
->tags
->breserved_tags
;
1378 if (!hctx_may_queue(rq
->mq_hctx
, bt
))
1382 tag
= __sbitmap_queue_get(bt
);
1383 if (tag
== BLK_MQ_NO_TAG
)
1386 rq
->tag
= tag
+ tag_offset
;
1390 bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
1392 if (rq
->tag
== BLK_MQ_NO_TAG
&& !__blk_mq_alloc_driver_tag(rq
))
1395 if ((hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
) &&
1396 !(rq
->rq_flags
& RQF_MQ_INFLIGHT
)) {
1397 rq
->rq_flags
|= RQF_MQ_INFLIGHT
;
1398 __blk_mq_inc_active_requests(hctx
);
1400 hctx
->tags
->rqs
[rq
->tag
] = rq
;
1404 static int blk_mq_dispatch_wake(wait_queue_entry_t
*wait
, unsigned mode
,
1405 int flags
, void *key
)
1407 struct blk_mq_hw_ctx
*hctx
;
1409 hctx
= container_of(wait
, struct blk_mq_hw_ctx
, dispatch_wait
);
1411 spin_lock(&hctx
->dispatch_wait_lock
);
1412 if (!list_empty(&wait
->entry
)) {
1413 struct sbitmap_queue
*sbq
;
1415 list_del_init(&wait
->entry
);
1416 sbq
= &hctx
->tags
->bitmap_tags
;
1417 atomic_dec(&sbq
->ws_active
);
1419 spin_unlock(&hctx
->dispatch_wait_lock
);
1421 blk_mq_run_hw_queue(hctx
, true);
1426 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1427 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1428 * restart. For both cases, take care to check the condition again after
1429 * marking us as waiting.
1431 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx
*hctx
,
1434 struct sbitmap_queue
*sbq
= &hctx
->tags
->bitmap_tags
;
1435 struct wait_queue_head
*wq
;
1436 wait_queue_entry_t
*wait
;
1439 if (!(hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)) {
1440 blk_mq_sched_mark_restart_hctx(hctx
);
1443 * It's possible that a tag was freed in the window between the
1444 * allocation failure and adding the hardware queue to the wait
1447 * Don't clear RESTART here, someone else could have set it.
1448 * At most this will cost an extra queue run.
1450 return blk_mq_get_driver_tag(rq
);
1453 wait
= &hctx
->dispatch_wait
;
1454 if (!list_empty_careful(&wait
->entry
))
1457 wq
= &bt_wait_ptr(sbq
, hctx
)->wait
;
1459 spin_lock_irq(&wq
->lock
);
1460 spin_lock(&hctx
->dispatch_wait_lock
);
1461 if (!list_empty(&wait
->entry
)) {
1462 spin_unlock(&hctx
->dispatch_wait_lock
);
1463 spin_unlock_irq(&wq
->lock
);
1467 atomic_inc(&sbq
->ws_active
);
1468 wait
->flags
&= ~WQ_FLAG_EXCLUSIVE
;
1469 __add_wait_queue(wq
, wait
);
1472 * It's possible that a tag was freed in the window between the
1473 * allocation failure and adding the hardware queue to the wait
1476 ret
= blk_mq_get_driver_tag(rq
);
1478 spin_unlock(&hctx
->dispatch_wait_lock
);
1479 spin_unlock_irq(&wq
->lock
);
1484 * We got a tag, remove ourselves from the wait queue to ensure
1485 * someone else gets the wakeup.
1487 list_del_init(&wait
->entry
);
1488 atomic_dec(&sbq
->ws_active
);
1489 spin_unlock(&hctx
->dispatch_wait_lock
);
1490 spin_unlock_irq(&wq
->lock
);
1495 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1496 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1498 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1499 * - EWMA is one simple way to compute running average value
1500 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1501 * - take 4 as factor for avoiding to get too small(0) result, and this
1502 * factor doesn't matter because EWMA decreases exponentially
1504 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx
*hctx
, bool busy
)
1508 ewma
= hctx
->dispatch_busy
;
1513 ewma
*= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
- 1;
1515 ewma
+= 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR
;
1516 ewma
/= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
;
1518 hctx
->dispatch_busy
= ewma
;
1521 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1523 static void blk_mq_handle_dev_resource(struct request
*rq
,
1524 struct list_head
*list
)
1526 struct request
*next
=
1527 list_first_entry_or_null(list
, struct request
, queuelist
);
1530 * If an I/O scheduler has been configured and we got a driver tag for
1531 * the next request already, free it.
1534 blk_mq_put_driver_tag(next
);
1536 list_add(&rq
->queuelist
, list
);
1537 __blk_mq_requeue_request(rq
);
1540 static void blk_mq_handle_zone_resource(struct request
*rq
,
1541 struct list_head
*zone_list
)
1544 * If we end up here it is because we cannot dispatch a request to a
1545 * specific zone due to LLD level zone-write locking or other zone
1546 * related resource not being available. In this case, set the request
1547 * aside in zone_list for retrying it later.
1549 list_add(&rq
->queuelist
, zone_list
);
1550 __blk_mq_requeue_request(rq
);
1553 enum prep_dispatch
{
1555 PREP_DISPATCH_NO_TAG
,
1556 PREP_DISPATCH_NO_BUDGET
,
1559 static enum prep_dispatch
blk_mq_prep_dispatch_rq(struct request
*rq
,
1562 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
1563 int budget_token
= -1;
1566 budget_token
= blk_mq_get_dispatch_budget(rq
->q
);
1567 if (budget_token
< 0) {
1568 blk_mq_put_driver_tag(rq
);
1569 return PREP_DISPATCH_NO_BUDGET
;
1571 blk_mq_set_rq_budget_token(rq
, budget_token
);
1574 if (!blk_mq_get_driver_tag(rq
)) {
1576 * The initial allocation attempt failed, so we need to
1577 * rerun the hardware queue when a tag is freed. The
1578 * waitqueue takes care of that. If the queue is run
1579 * before we add this entry back on the dispatch list,
1580 * we'll re-run it below.
1582 if (!blk_mq_mark_tag_wait(hctx
, rq
)) {
1584 * All budgets not got from this function will be put
1585 * together during handling partial dispatch
1588 blk_mq_put_dispatch_budget(rq
->q
, budget_token
);
1589 return PREP_DISPATCH_NO_TAG
;
1593 return PREP_DISPATCH_OK
;
1596 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1597 static void blk_mq_release_budgets(struct request_queue
*q
,
1598 struct list_head
*list
)
1602 list_for_each_entry(rq
, list
, queuelist
) {
1603 int budget_token
= blk_mq_get_rq_budget_token(rq
);
1605 if (budget_token
>= 0)
1606 blk_mq_put_dispatch_budget(q
, budget_token
);
1611 * Returns true if we did some work AND can potentially do more.
1613 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
,
1614 unsigned int nr_budgets
)
1616 enum prep_dispatch prep
;
1617 struct request_queue
*q
= hctx
->queue
;
1618 struct request
*rq
, *nxt
;
1620 blk_status_t ret
= BLK_STS_OK
;
1621 LIST_HEAD(zone_list
);
1622 bool needs_resource
= false;
1624 if (list_empty(list
))
1628 * Now process all the entries, sending them to the driver.
1630 errors
= queued
= 0;
1632 struct blk_mq_queue_data bd
;
1634 rq
= list_first_entry(list
, struct request
, queuelist
);
1636 WARN_ON_ONCE(hctx
!= rq
->mq_hctx
);
1637 prep
= blk_mq_prep_dispatch_rq(rq
, !nr_budgets
);
1638 if (prep
!= PREP_DISPATCH_OK
)
1641 list_del_init(&rq
->queuelist
);
1646 * Flag last if we have no more requests, or if we have more
1647 * but can't assign a driver tag to it.
1649 if (list_empty(list
))
1652 nxt
= list_first_entry(list
, struct request
, queuelist
);
1653 bd
.last
= !blk_mq_get_driver_tag(nxt
);
1657 * once the request is queued to lld, no need to cover the
1662 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1667 case BLK_STS_RESOURCE
:
1668 needs_resource
= true;
1670 case BLK_STS_DEV_RESOURCE
:
1671 blk_mq_handle_dev_resource(rq
, list
);
1673 case BLK_STS_ZONE_RESOURCE
:
1675 * Move the request to zone_list and keep going through
1676 * the dispatch list to find more requests the drive can
1679 blk_mq_handle_zone_resource(rq
, &zone_list
);
1680 needs_resource
= true;
1684 blk_mq_end_request(rq
, ret
);
1686 } while (!list_empty(list
));
1688 if (!list_empty(&zone_list
))
1689 list_splice_tail_init(&zone_list
, list
);
1691 /* If we didn't flush the entire list, we could have told the driver
1692 * there was more coming, but that turned out to be a lie.
1694 if ((!list_empty(list
) || errors
) && q
->mq_ops
->commit_rqs
&& queued
)
1695 q
->mq_ops
->commit_rqs(hctx
);
1697 * Any items that need requeuing? Stuff them into hctx->dispatch,
1698 * that is where we will continue on next queue run.
1700 if (!list_empty(list
)) {
1702 /* For non-shared tags, the RESTART check will suffice */
1703 bool no_tag
= prep
== PREP_DISPATCH_NO_TAG
&&
1704 (hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
);
1707 blk_mq_release_budgets(q
, list
);
1709 spin_lock(&hctx
->lock
);
1710 list_splice_tail_init(list
, &hctx
->dispatch
);
1711 spin_unlock(&hctx
->lock
);
1714 * Order adding requests to hctx->dispatch and checking
1715 * SCHED_RESTART flag. The pair of this smp_mb() is the one
1716 * in blk_mq_sched_restart(). Avoid restart code path to
1717 * miss the new added requests to hctx->dispatch, meantime
1718 * SCHED_RESTART is observed here.
1723 * If SCHED_RESTART was set by the caller of this function and
1724 * it is no longer set that means that it was cleared by another
1725 * thread and hence that a queue rerun is needed.
1727 * If 'no_tag' is set, that means that we failed getting
1728 * a driver tag with an I/O scheduler attached. If our dispatch
1729 * waitqueue is no longer active, ensure that we run the queue
1730 * AFTER adding our entries back to the list.
1732 * If no I/O scheduler has been configured it is possible that
1733 * the hardware queue got stopped and restarted before requests
1734 * were pushed back onto the dispatch list. Rerun the queue to
1735 * avoid starvation. Notes:
1736 * - blk_mq_run_hw_queue() checks whether or not a queue has
1737 * been stopped before rerunning a queue.
1738 * - Some but not all block drivers stop a queue before
1739 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
1742 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
1743 * bit is set, run queue after a delay to avoid IO stalls
1744 * that could otherwise occur if the queue is idle. We'll do
1745 * similar if we couldn't get budget or couldn't lock a zone
1746 * and SCHED_RESTART is set.
1748 needs_restart
= blk_mq_sched_needs_restart(hctx
);
1749 if (prep
== PREP_DISPATCH_NO_BUDGET
)
1750 needs_resource
= true;
1751 if (!needs_restart
||
1752 (no_tag
&& list_empty_careful(&hctx
->dispatch_wait
.entry
)))
1753 blk_mq_run_hw_queue(hctx
, true);
1754 else if (needs_restart
&& needs_resource
)
1755 blk_mq_delay_run_hw_queue(hctx
, BLK_MQ_RESOURCE_DELAY
);
1757 blk_mq_update_dispatch_busy(hctx
, true);
1760 blk_mq_update_dispatch_busy(hctx
, false);
1762 return (queued
+ errors
) != 0;
1766 * __blk_mq_run_hw_queue - Run a hardware queue.
1767 * @hctx: Pointer to the hardware queue to run.
1769 * Send pending requests to the hardware.
1771 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1776 * We can't run the queue inline with ints disabled. Ensure that
1777 * we catch bad users of this early.
1779 WARN_ON_ONCE(in_interrupt());
1781 might_sleep_if(hctx
->flags
& BLK_MQ_F_BLOCKING
);
1783 hctx_lock(hctx
, &srcu_idx
);
1784 blk_mq_sched_dispatch_requests(hctx
);
1785 hctx_unlock(hctx
, srcu_idx
);
1788 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx
*hctx
)
1790 int cpu
= cpumask_first_and(hctx
->cpumask
, cpu_online_mask
);
1792 if (cpu
>= nr_cpu_ids
)
1793 cpu
= cpumask_first(hctx
->cpumask
);
1798 * It'd be great if the workqueue API had a way to pass
1799 * in a mask and had some smarts for more clever placement.
1800 * For now we just round-robin here, switching for every
1801 * BLK_MQ_CPU_WORK_BATCH queued items.
1803 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
1806 int next_cpu
= hctx
->next_cpu
;
1808 if (hctx
->queue
->nr_hw_queues
== 1)
1809 return WORK_CPU_UNBOUND
;
1811 if (--hctx
->next_cpu_batch
<= 0) {
1813 next_cpu
= cpumask_next_and(next_cpu
, hctx
->cpumask
,
1815 if (next_cpu
>= nr_cpu_ids
)
1816 next_cpu
= blk_mq_first_mapped_cpu(hctx
);
1817 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1821 * Do unbound schedule if we can't find a online CPU for this hctx,
1822 * and it should only happen in the path of handling CPU DEAD.
1824 if (!cpu_online(next_cpu
)) {
1831 * Make sure to re-select CPU next time once after CPUs
1832 * in hctx->cpumask become online again.
1834 hctx
->next_cpu
= next_cpu
;
1835 hctx
->next_cpu_batch
= 1;
1836 return WORK_CPU_UNBOUND
;
1839 hctx
->next_cpu
= next_cpu
;
1844 * __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue.
1845 * @hctx: Pointer to the hardware queue to run.
1846 * @async: If we want to run the queue asynchronously.
1847 * @msecs: Milliseconds of delay to wait before running the queue.
1849 * If !@async, try to run the queue now. Else, run the queue asynchronously and
1850 * with a delay of @msecs.
1852 static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
,
1853 unsigned long msecs
)
1855 if (unlikely(blk_mq_hctx_stopped(hctx
)))
1858 if (!async
&& !(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1859 int cpu
= get_cpu();
1860 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
1861 __blk_mq_run_hw_queue(hctx
);
1869 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx
), &hctx
->run_work
,
1870 msecs_to_jiffies(msecs
));
1874 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
1875 * @hctx: Pointer to the hardware queue to run.
1876 * @msecs: Milliseconds of delay to wait before running the queue.
1878 * Run a hardware queue asynchronously with a delay of @msecs.
1880 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1882 __blk_mq_delay_run_hw_queue(hctx
, true, msecs
);
1884 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue
);
1887 * blk_mq_run_hw_queue - Start to run a hardware queue.
1888 * @hctx: Pointer to the hardware queue to run.
1889 * @async: If we want to run the queue asynchronously.
1891 * Check if the request queue is not in a quiesced state and if there are
1892 * pending requests to be sent. If this is true, run the queue to send requests
1895 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1901 * When queue is quiesced, we may be switching io scheduler, or
1902 * updating nr_hw_queues, or other things, and we can't run queue
1903 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
1905 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
1908 hctx_lock(hctx
, &srcu_idx
);
1909 need_run
= !blk_queue_quiesced(hctx
->queue
) &&
1910 blk_mq_hctx_has_pending(hctx
);
1911 hctx_unlock(hctx
, srcu_idx
);
1914 __blk_mq_delay_run_hw_queue(hctx
, async
, 0);
1916 EXPORT_SYMBOL(blk_mq_run_hw_queue
);
1919 * Is the request queue handled by an IO scheduler that does not respect
1920 * hardware queues when dispatching?
1922 static bool blk_mq_has_sqsched(struct request_queue
*q
)
1924 struct elevator_queue
*e
= q
->elevator
;
1926 if (e
&& e
->type
->ops
.dispatch_request
&&
1927 !(e
->type
->elevator_features
& ELEVATOR_F_MQ_AWARE
))
1933 * Return prefered queue to dispatch from (if any) for non-mq aware IO
1936 static struct blk_mq_hw_ctx
*blk_mq_get_sq_hctx(struct request_queue
*q
)
1938 struct blk_mq_hw_ctx
*hctx
;
1941 * If the IO scheduler does not respect hardware queues when
1942 * dispatching, we just don't bother with multiple HW queues and
1943 * dispatch from hctx for the current CPU since running multiple queues
1944 * just causes lock contention inside the scheduler and pointless cache
1947 hctx
= blk_mq_map_queue_type(q
, HCTX_TYPE_DEFAULT
,
1948 raw_smp_processor_id());
1949 if (!blk_mq_hctx_stopped(hctx
))
1955 * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
1956 * @q: Pointer to the request queue to run.
1957 * @async: If we want to run the queue asynchronously.
1959 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
1961 struct blk_mq_hw_ctx
*hctx
, *sq_hctx
;
1965 if (blk_mq_has_sqsched(q
))
1966 sq_hctx
= blk_mq_get_sq_hctx(q
);
1967 queue_for_each_hw_ctx(q
, hctx
, i
) {
1968 if (blk_mq_hctx_stopped(hctx
))
1971 * Dispatch from this hctx either if there's no hctx preferred
1972 * by IO scheduler or if it has requests that bypass the
1975 if (!sq_hctx
|| sq_hctx
== hctx
||
1976 !list_empty_careful(&hctx
->dispatch
))
1977 blk_mq_run_hw_queue(hctx
, async
);
1980 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
1983 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
1984 * @q: Pointer to the request queue to run.
1985 * @msecs: Milliseconds of delay to wait before running the queues.
1987 void blk_mq_delay_run_hw_queues(struct request_queue
*q
, unsigned long msecs
)
1989 struct blk_mq_hw_ctx
*hctx
, *sq_hctx
;
1993 if (blk_mq_has_sqsched(q
))
1994 sq_hctx
= blk_mq_get_sq_hctx(q
);
1995 queue_for_each_hw_ctx(q
, hctx
, i
) {
1996 if (blk_mq_hctx_stopped(hctx
))
1999 * Dispatch from this hctx either if there's no hctx preferred
2000 * by IO scheduler or if it has requests that bypass the
2003 if (!sq_hctx
|| sq_hctx
== hctx
||
2004 !list_empty_careful(&hctx
->dispatch
))
2005 blk_mq_delay_run_hw_queue(hctx
, msecs
);
2008 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues
);
2011 * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
2012 * @q: request queue.
2014 * The caller is responsible for serializing this function against
2015 * blk_mq_{start,stop}_hw_queue().
2017 bool blk_mq_queue_stopped(struct request_queue
*q
)
2019 struct blk_mq_hw_ctx
*hctx
;
2022 queue_for_each_hw_ctx(q
, hctx
, i
)
2023 if (blk_mq_hctx_stopped(hctx
))
2028 EXPORT_SYMBOL(blk_mq_queue_stopped
);
2031 * This function is often used for pausing .queue_rq() by driver when
2032 * there isn't enough resource or some conditions aren't satisfied, and
2033 * BLK_STS_RESOURCE is usually returned.
2035 * We do not guarantee that dispatch can be drained or blocked
2036 * after blk_mq_stop_hw_queue() returns. Please use
2037 * blk_mq_quiesce_queue() for that requirement.
2039 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
2041 cancel_delayed_work(&hctx
->run_work
);
2043 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
2045 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
2048 * This function is often used for pausing .queue_rq() by driver when
2049 * there isn't enough resource or some conditions aren't satisfied, and
2050 * BLK_STS_RESOURCE is usually returned.
2052 * We do not guarantee that dispatch can be drained or blocked
2053 * after blk_mq_stop_hw_queues() returns. Please use
2054 * blk_mq_quiesce_queue() for that requirement.
2056 void blk_mq_stop_hw_queues(struct request_queue
*q
)
2058 struct blk_mq_hw_ctx
*hctx
;
2061 queue_for_each_hw_ctx(q
, hctx
, i
)
2062 blk_mq_stop_hw_queue(hctx
);
2064 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
2066 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
2068 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
2070 blk_mq_run_hw_queue(hctx
, false);
2072 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
2074 void blk_mq_start_hw_queues(struct request_queue
*q
)
2076 struct blk_mq_hw_ctx
*hctx
;
2079 queue_for_each_hw_ctx(q
, hctx
, i
)
2080 blk_mq_start_hw_queue(hctx
);
2082 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
2084 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
2086 if (!blk_mq_hctx_stopped(hctx
))
2089 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
2090 blk_mq_run_hw_queue(hctx
, async
);
2092 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue
);
2094 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
2096 struct blk_mq_hw_ctx
*hctx
;
2099 queue_for_each_hw_ctx(q
, hctx
, i
)
2100 blk_mq_start_stopped_hw_queue(hctx
, async
);
2102 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
2104 static void blk_mq_run_work_fn(struct work_struct
*work
)
2106 struct blk_mq_hw_ctx
*hctx
;
2108 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
2111 * If we are stopped, don't run the queue.
2113 if (blk_mq_hctx_stopped(hctx
))
2116 __blk_mq_run_hw_queue(hctx
);
2119 static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx
*hctx
,
2123 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
2124 enum hctx_type type
= hctx
->type
;
2126 lockdep_assert_held(&ctx
->lock
);
2128 trace_block_rq_insert(rq
);
2131 list_add(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
2133 list_add_tail(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
2136 void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
2139 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
2141 lockdep_assert_held(&ctx
->lock
);
2143 __blk_mq_insert_req_list(hctx
, rq
, at_head
);
2144 blk_mq_hctx_mark_pending(hctx
, ctx
);
2148 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2149 * @rq: Pointer to request to be inserted.
2150 * @at_head: true if the request should be inserted at the head of the list.
2151 * @run_queue: If we should run the hardware queue after inserting the request.
2153 * Should only be used carefully, when the caller knows we want to
2154 * bypass a potential IO scheduler on the target device.
2156 void blk_mq_request_bypass_insert(struct request
*rq
, bool at_head
,
2159 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
2161 spin_lock(&hctx
->lock
);
2163 list_add(&rq
->queuelist
, &hctx
->dispatch
);
2165 list_add_tail(&rq
->queuelist
, &hctx
->dispatch
);
2166 spin_unlock(&hctx
->lock
);
2169 blk_mq_run_hw_queue(hctx
, false);
2172 void blk_mq_insert_requests(struct blk_mq_hw_ctx
*hctx
, struct blk_mq_ctx
*ctx
,
2173 struct list_head
*list
)
2177 enum hctx_type type
= hctx
->type
;
2180 * preemption doesn't flush plug list, so it's possible ctx->cpu is
2183 list_for_each_entry(rq
, list
, queuelist
) {
2184 BUG_ON(rq
->mq_ctx
!= ctx
);
2185 trace_block_rq_insert(rq
);
2188 spin_lock(&ctx
->lock
);
2189 list_splice_tail_init(list
, &ctx
->rq_lists
[type
]);
2190 blk_mq_hctx_mark_pending(hctx
, ctx
);
2191 spin_unlock(&ctx
->lock
);
2194 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx
*hctx
, int *queued
,
2197 if (hctx
->queue
->mq_ops
->commit_rqs
) {
2198 trace_block_unplug(hctx
->queue
, *queued
, !from_schedule
);
2199 hctx
->queue
->mq_ops
->commit_rqs(hctx
);
2204 static void blk_mq_plug_issue_direct(struct blk_plug
*plug
, bool from_schedule
)
2206 struct blk_mq_hw_ctx
*hctx
= NULL
;
2211 while ((rq
= rq_list_pop(&plug
->mq_list
))) {
2212 bool last
= rq_list_empty(plug
->mq_list
);
2215 if (hctx
!= rq
->mq_hctx
) {
2217 blk_mq_commit_rqs(hctx
, &queued
, from_schedule
);
2221 ret
= blk_mq_request_issue_directly(rq
, last
);
2226 case BLK_STS_RESOURCE
:
2227 case BLK_STS_DEV_RESOURCE
:
2228 blk_mq_request_bypass_insert(rq
, false, last
);
2229 blk_mq_commit_rqs(hctx
, &queued
, from_schedule
);
2232 blk_mq_end_request(rq
, ret
);
2239 * If we didn't flush the entire list, we could have told the driver
2240 * there was more coming, but that turned out to be a lie.
2243 blk_mq_commit_rqs(hctx
, &queued
, from_schedule
);
2246 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
2248 struct blk_mq_hw_ctx
*this_hctx
;
2249 struct blk_mq_ctx
*this_ctx
;
2253 if (rq_list_empty(plug
->mq_list
))
2257 if (!plug
->multiple_queues
&& !plug
->has_elevator
&& !from_schedule
) {
2258 blk_mq_plug_issue_direct(plug
, false);
2259 if (rq_list_empty(plug
->mq_list
))
2269 rq
= rq_list_pop(&plug
->mq_list
);
2272 this_hctx
= rq
->mq_hctx
;
2273 this_ctx
= rq
->mq_ctx
;
2274 } else if (this_hctx
!= rq
->mq_hctx
|| this_ctx
!= rq
->mq_ctx
) {
2275 trace_block_unplug(this_hctx
->queue
, depth
,
2277 blk_mq_sched_insert_requests(this_hctx
, this_ctx
,
2278 &list
, from_schedule
);
2280 this_hctx
= rq
->mq_hctx
;
2281 this_ctx
= rq
->mq_ctx
;
2285 list_add(&rq
->queuelist
, &list
);
2287 } while (!rq_list_empty(plug
->mq_list
));
2289 if (!list_empty(&list
)) {
2290 trace_block_unplug(this_hctx
->queue
, depth
, !from_schedule
);
2291 blk_mq_sched_insert_requests(this_hctx
, this_ctx
, &list
,
2296 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
,
2297 unsigned int nr_segs
)
2301 if (bio
->bi_opf
& REQ_RAHEAD
)
2302 rq
->cmd_flags
|= REQ_FAILFAST_MASK
;
2304 rq
->__sector
= bio
->bi_iter
.bi_sector
;
2305 rq
->write_hint
= bio
->bi_write_hint
;
2306 blk_rq_bio_prep(rq
, bio
, nr_segs
);
2308 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2309 err
= blk_crypto_rq_bio_prep(rq
, bio
, GFP_NOIO
);
2312 blk_account_io_start(rq
);
2315 static blk_status_t
__blk_mq_issue_directly(struct blk_mq_hw_ctx
*hctx
,
2316 struct request
*rq
, bool last
)
2318 struct request_queue
*q
= rq
->q
;
2319 struct blk_mq_queue_data bd
= {
2326 * For OK queue, we are done. For error, caller may kill it.
2327 * Any other error (busy), just add it to our list as we
2328 * previously would have done.
2330 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
2333 blk_mq_update_dispatch_busy(hctx
, false);
2335 case BLK_STS_RESOURCE
:
2336 case BLK_STS_DEV_RESOURCE
:
2337 blk_mq_update_dispatch_busy(hctx
, true);
2338 __blk_mq_requeue_request(rq
);
2341 blk_mq_update_dispatch_busy(hctx
, false);
2348 static blk_status_t
__blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
2350 bool bypass_insert
, bool last
)
2352 struct request_queue
*q
= rq
->q
;
2353 bool run_queue
= true;
2357 * RCU or SRCU read lock is needed before checking quiesced flag.
2359 * When queue is stopped or quiesced, ignore 'bypass_insert' from
2360 * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
2361 * and avoid driver to try to dispatch again.
2363 if (blk_mq_hctx_stopped(hctx
) || blk_queue_quiesced(q
)) {
2365 bypass_insert
= false;
2369 if ((rq
->rq_flags
& RQF_ELV
) && !bypass_insert
)
2372 budget_token
= blk_mq_get_dispatch_budget(q
);
2373 if (budget_token
< 0)
2376 blk_mq_set_rq_budget_token(rq
, budget_token
);
2378 if (!blk_mq_get_driver_tag(rq
)) {
2379 blk_mq_put_dispatch_budget(q
, budget_token
);
2383 return __blk_mq_issue_directly(hctx
, rq
, last
);
2386 return BLK_STS_RESOURCE
;
2388 blk_mq_sched_insert_request(rq
, false, run_queue
, false);
2394 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2395 * @hctx: Pointer of the associated hardware queue.
2396 * @rq: Pointer to request to be sent.
2398 * If the device has enough resources to accept a new request now, send the
2399 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2400 * we can try send it another time in the future. Requests inserted at this
2401 * queue have higher priority.
2403 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
2409 might_sleep_if(hctx
->flags
& BLK_MQ_F_BLOCKING
);
2411 hctx_lock(hctx
, &srcu_idx
);
2413 ret
= __blk_mq_try_issue_directly(hctx
, rq
, false, true);
2414 if (ret
== BLK_STS_RESOURCE
|| ret
== BLK_STS_DEV_RESOURCE
)
2415 blk_mq_request_bypass_insert(rq
, false, true);
2416 else if (ret
!= BLK_STS_OK
)
2417 blk_mq_end_request(rq
, ret
);
2419 hctx_unlock(hctx
, srcu_idx
);
2422 blk_status_t
blk_mq_request_issue_directly(struct request
*rq
, bool last
)
2426 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
2428 hctx_lock(hctx
, &srcu_idx
);
2429 ret
= __blk_mq_try_issue_directly(hctx
, rq
, true, last
);
2430 hctx_unlock(hctx
, srcu_idx
);
2435 void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx
*hctx
,
2436 struct list_head
*list
)
2441 while (!list_empty(list
)) {
2443 struct request
*rq
= list_first_entry(list
, struct request
,
2446 list_del_init(&rq
->queuelist
);
2447 ret
= blk_mq_request_issue_directly(rq
, list_empty(list
));
2448 if (ret
!= BLK_STS_OK
) {
2449 if (ret
== BLK_STS_RESOURCE
||
2450 ret
== BLK_STS_DEV_RESOURCE
) {
2451 blk_mq_request_bypass_insert(rq
, false,
2455 blk_mq_end_request(rq
, ret
);
2462 * If we didn't flush the entire list, we could have told
2463 * the driver there was more coming, but that turned out to
2466 if ((!list_empty(list
) || errors
) &&
2467 hctx
->queue
->mq_ops
->commit_rqs
&& queued
)
2468 hctx
->queue
->mq_ops
->commit_rqs(hctx
);
2471 static void blk_add_rq_to_plug(struct blk_plug
*plug
, struct request
*rq
)
2473 if (!plug
->multiple_queues
) {
2474 struct request
*nxt
= rq_list_peek(&plug
->mq_list
);
2476 if (nxt
&& nxt
->q
!= rq
->q
)
2477 plug
->multiple_queues
= true;
2479 if (!plug
->has_elevator
&& (rq
->rq_flags
& RQF_ELV
))
2480 plug
->has_elevator
= true;
2482 rq_list_add(&plug
->mq_list
, rq
);
2487 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
2488 * queues. This is important for md arrays to benefit from merging
2491 static inline unsigned short blk_plug_max_rq_count(struct blk_plug
*plug
)
2493 if (plug
->multiple_queues
)
2494 return BLK_MAX_REQUEST_COUNT
* 2;
2495 return BLK_MAX_REQUEST_COUNT
;
2498 static bool blk_attempt_bio_merge(struct request_queue
*q
, struct bio
*bio
,
2499 unsigned int nr_segs
, bool *same_queue_rq
)
2501 if (!blk_queue_nomerges(q
) && bio_mergeable(bio
)) {
2502 if (blk_attempt_plug_merge(q
, bio
, nr_segs
, same_queue_rq
))
2504 if (blk_mq_sched_bio_merge(q
, bio
, nr_segs
))
2510 static struct request
*blk_mq_get_new_requests(struct request_queue
*q
,
2511 struct blk_plug
*plug
,
2514 bool *same_queue_rq
)
2516 struct blk_mq_alloc_data data
= {
2519 .cmd_flags
= bio
->bi_opf
,
2523 if (unlikely(bio_queue_enter(bio
)))
2525 if (unlikely(!submit_bio_checks(bio
)))
2527 if (blk_attempt_bio_merge(q
, bio
, nsegs
, same_queue_rq
))
2530 rq_qos_throttle(q
, bio
);
2533 data
.nr_tags
= plug
->nr_ios
;
2535 data
.cached_rq
= &plug
->cached_rq
;
2538 rq
= __blk_mq_alloc_requests(&data
);
2542 rq_qos_cleanup(q
, bio
);
2543 if (bio
->bi_opf
& REQ_NOWAIT
)
2544 bio_wouldblock_error(bio
);
2550 static inline struct request
*blk_mq_get_request(struct request_queue
*q
,
2551 struct blk_plug
*plug
,
2554 bool *same_queue_rq
)
2559 rq
= rq_list_peek(&plug
->cached_rq
);
2560 if (rq
&& rq
->q
== q
) {
2561 if (unlikely(!submit_bio_checks(bio
)))
2563 if (blk_attempt_bio_merge(q
, bio
, nsegs
, same_queue_rq
))
2565 plug
->cached_rq
= rq_list_next(rq
);
2566 INIT_LIST_HEAD(&rq
->queuelist
);
2567 rq_qos_throttle(q
, bio
);
2572 return blk_mq_get_new_requests(q
, plug
, bio
, nsegs
, same_queue_rq
);
2576 * blk_mq_submit_bio - Create and send a request to block device.
2577 * @bio: Bio pointer.
2579 * Builds up a request structure from @q and @bio and send to the device. The
2580 * request may not be queued directly to hardware if:
2581 * * This request can be merged with another one
2582 * * We want to place request at plug queue for possible future merging
2583 * * There is an IO scheduler active at this queue
2585 * It will not queue the request if there is an error with the bio, or at the
2588 void blk_mq_submit_bio(struct bio
*bio
)
2590 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
2591 const int is_sync
= op_is_sync(bio
->bi_opf
);
2593 struct blk_plug
*plug
;
2594 bool same_queue_rq
= false;
2595 unsigned int nr_segs
= 1;
2598 if (unlikely(!blk_crypto_bio_prep(&bio
)))
2601 blk_queue_bounce(q
, &bio
);
2602 if (blk_may_split(q
, bio
))
2603 __blk_queue_split(q
, &bio
, &nr_segs
);
2605 if (!bio_integrity_prep(bio
))
2608 plug
= blk_mq_plug(q
, bio
);
2609 rq
= blk_mq_get_request(q
, plug
, bio
, nr_segs
, &same_queue_rq
);
2613 trace_block_getrq(bio
);
2615 rq_qos_track(q
, rq
, bio
);
2617 blk_mq_bio_to_request(rq
, bio
, nr_segs
);
2619 ret
= blk_crypto_init_request(rq
);
2620 if (ret
!= BLK_STS_OK
) {
2621 bio
->bi_status
= ret
;
2623 blk_mq_free_request(rq
);
2627 if (op_is_flush(bio
->bi_opf
) && blk_insert_flush(rq
))
2630 if (plug
&& (q
->nr_hw_queues
== 1 ||
2631 blk_mq_is_shared_tags(rq
->mq_hctx
->flags
) ||
2632 q
->mq_ops
->commit_rqs
|| !blk_queue_nonrot(q
))) {
2634 * Use plugging if we have a ->commit_rqs() hook as well, as
2635 * we know the driver uses bd->last in a smart fashion.
2637 * Use normal plugging if this disk is slow HDD, as sequential
2638 * IO may benefit a lot from plug merging.
2640 unsigned int request_count
= plug
->rq_count
;
2641 struct request
*last
= NULL
;
2643 if (!request_count
) {
2644 trace_block_plug(q
);
2645 } else if (!blk_queue_nomerges(q
)) {
2646 last
= rq_list_peek(&plug
->mq_list
);
2647 if (blk_rq_bytes(last
) < BLK_PLUG_FLUSH_SIZE
)
2651 if (request_count
>= blk_plug_max_rq_count(plug
) || last
) {
2652 blk_mq_flush_plug_list(plug
, false);
2653 trace_block_plug(q
);
2656 blk_add_rq_to_plug(plug
, rq
);
2657 } else if (rq
->rq_flags
& RQF_ELV
) {
2658 /* Insert the request at the IO scheduler queue */
2659 blk_mq_sched_insert_request(rq
, false, true, true);
2660 } else if (plug
&& !blk_queue_nomerges(q
)) {
2661 struct request
*next_rq
= NULL
;
2664 * We do limited plugging. If the bio can be merged, do that.
2665 * Otherwise the existing request in the plug list will be
2666 * issued. So the plug list will have one request at most
2667 * The plug list might get flushed before this. If that happens,
2668 * the plug list is empty, and same_queue_rq is invalid.
2670 if (same_queue_rq
) {
2671 next_rq
= rq_list_pop(&plug
->mq_list
);
2674 blk_add_rq_to_plug(plug
, rq
);
2675 trace_block_plug(q
);
2678 trace_block_unplug(q
, 1, true);
2679 blk_mq_try_issue_directly(next_rq
->mq_hctx
, next_rq
);
2681 } else if ((q
->nr_hw_queues
> 1 && is_sync
) ||
2682 !rq
->mq_hctx
->dispatch_busy
) {
2684 * There is no scheduler and we can try to send directly
2687 blk_mq_try_issue_directly(rq
->mq_hctx
, rq
);
2690 blk_mq_sched_insert_request(rq
, false, true, true);
2694 static size_t order_to_size(unsigned int order
)
2696 return (size_t)PAGE_SIZE
<< order
;
2699 /* called before freeing request pool in @tags */
2700 static void blk_mq_clear_rq_mapping(struct blk_mq_tags
*drv_tags
,
2701 struct blk_mq_tags
*tags
)
2704 unsigned long flags
;
2706 /* There is no need to clear a driver tags own mapping */
2707 if (drv_tags
== tags
)
2710 list_for_each_entry(page
, &tags
->page_list
, lru
) {
2711 unsigned long start
= (unsigned long)page_address(page
);
2712 unsigned long end
= start
+ order_to_size(page
->private);
2715 for (i
= 0; i
< drv_tags
->nr_tags
; i
++) {
2716 struct request
*rq
= drv_tags
->rqs
[i
];
2717 unsigned long rq_addr
= (unsigned long)rq
;
2719 if (rq_addr
>= start
&& rq_addr
< end
) {
2720 WARN_ON_ONCE(refcount_read(&rq
->ref
) != 0);
2721 cmpxchg(&drv_tags
->rqs
[i
], rq
, NULL
);
2727 * Wait until all pending iteration is done.
2729 * Request reference is cleared and it is guaranteed to be observed
2730 * after the ->lock is released.
2732 spin_lock_irqsave(&drv_tags
->lock
, flags
);
2733 spin_unlock_irqrestore(&drv_tags
->lock
, flags
);
2736 void blk_mq_free_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
2737 unsigned int hctx_idx
)
2739 struct blk_mq_tags
*drv_tags
;
2742 if (blk_mq_is_shared_tags(set
->flags
))
2743 drv_tags
= set
->shared_tags
;
2745 drv_tags
= set
->tags
[hctx_idx
];
2747 if (tags
->static_rqs
&& set
->ops
->exit_request
) {
2750 for (i
= 0; i
< tags
->nr_tags
; i
++) {
2751 struct request
*rq
= tags
->static_rqs
[i
];
2755 set
->ops
->exit_request(set
, rq
, hctx_idx
);
2756 tags
->static_rqs
[i
] = NULL
;
2760 blk_mq_clear_rq_mapping(drv_tags
, tags
);
2762 while (!list_empty(&tags
->page_list
)) {
2763 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
2764 list_del_init(&page
->lru
);
2766 * Remove kmemleak object previously allocated in
2767 * blk_mq_alloc_rqs().
2769 kmemleak_free(page_address(page
));
2770 __free_pages(page
, page
->private);
2774 void blk_mq_free_rq_map(struct blk_mq_tags
*tags
)
2778 kfree(tags
->static_rqs
);
2779 tags
->static_rqs
= NULL
;
2781 blk_mq_free_tags(tags
);
2784 static struct blk_mq_tags
*blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
,
2785 unsigned int hctx_idx
,
2786 unsigned int nr_tags
,
2787 unsigned int reserved_tags
)
2789 struct blk_mq_tags
*tags
;
2792 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], hctx_idx
);
2793 if (node
== NUMA_NO_NODE
)
2794 node
= set
->numa_node
;
2796 tags
= blk_mq_init_tags(nr_tags
, reserved_tags
, node
,
2797 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
2801 tags
->rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
2802 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
2805 blk_mq_free_tags(tags
);
2809 tags
->static_rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
2810 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
2812 if (!tags
->static_rqs
) {
2814 blk_mq_free_tags(tags
);
2821 static int blk_mq_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
2822 unsigned int hctx_idx
, int node
)
2826 if (set
->ops
->init_request
) {
2827 ret
= set
->ops
->init_request(set
, rq
, hctx_idx
, node
);
2832 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
2836 static int blk_mq_alloc_rqs(struct blk_mq_tag_set
*set
,
2837 struct blk_mq_tags
*tags
,
2838 unsigned int hctx_idx
, unsigned int depth
)
2840 unsigned int i
, j
, entries_per_page
, max_order
= 4;
2841 size_t rq_size
, left
;
2844 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], hctx_idx
);
2845 if (node
== NUMA_NO_NODE
)
2846 node
= set
->numa_node
;
2848 INIT_LIST_HEAD(&tags
->page_list
);
2851 * rq_size is the size of the request plus driver payload, rounded
2852 * to the cacheline size
2854 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
2856 left
= rq_size
* depth
;
2858 for (i
= 0; i
< depth
; ) {
2859 int this_order
= max_order
;
2864 while (this_order
&& left
< order_to_size(this_order
- 1))
2868 page
= alloc_pages_node(node
,
2869 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
2875 if (order_to_size(this_order
) < rq_size
)
2882 page
->private = this_order
;
2883 list_add_tail(&page
->lru
, &tags
->page_list
);
2885 p
= page_address(page
);
2887 * Allow kmemleak to scan these pages as they contain pointers
2888 * to additional allocations like via ops->init_request().
2890 kmemleak_alloc(p
, order_to_size(this_order
), 1, GFP_NOIO
);
2891 entries_per_page
= order_to_size(this_order
) / rq_size
;
2892 to_do
= min(entries_per_page
, depth
- i
);
2893 left
-= to_do
* rq_size
;
2894 for (j
= 0; j
< to_do
; j
++) {
2895 struct request
*rq
= p
;
2897 tags
->static_rqs
[i
] = rq
;
2898 if (blk_mq_init_request(set
, rq
, hctx_idx
, node
)) {
2899 tags
->static_rqs
[i
] = NULL
;
2910 blk_mq_free_rqs(set
, tags
, hctx_idx
);
2914 struct rq_iter_data
{
2915 struct blk_mq_hw_ctx
*hctx
;
2919 static bool blk_mq_has_request(struct request
*rq
, void *data
, bool reserved
)
2921 struct rq_iter_data
*iter_data
= data
;
2923 if (rq
->mq_hctx
!= iter_data
->hctx
)
2925 iter_data
->has_rq
= true;
2929 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx
*hctx
)
2931 struct blk_mq_tags
*tags
= hctx
->sched_tags
?
2932 hctx
->sched_tags
: hctx
->tags
;
2933 struct rq_iter_data data
= {
2937 blk_mq_all_tag_iter(tags
, blk_mq_has_request
, &data
);
2941 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu
,
2942 struct blk_mq_hw_ctx
*hctx
)
2944 if (cpumask_next_and(-1, hctx
->cpumask
, cpu_online_mask
) != cpu
)
2946 if (cpumask_next_and(cpu
, hctx
->cpumask
, cpu_online_mask
) < nr_cpu_ids
)
2951 static int blk_mq_hctx_notify_offline(unsigned int cpu
, struct hlist_node
*node
)
2953 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
2954 struct blk_mq_hw_ctx
, cpuhp_online
);
2956 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
) ||
2957 !blk_mq_last_cpu_in_hctx(cpu
, hctx
))
2961 * Prevent new request from being allocated on the current hctx.
2963 * The smp_mb__after_atomic() Pairs with the implied barrier in
2964 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
2965 * seen once we return from the tag allocator.
2967 set_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
2968 smp_mb__after_atomic();
2971 * Try to grab a reference to the queue and wait for any outstanding
2972 * requests. If we could not grab a reference the queue has been
2973 * frozen and there are no requests.
2975 if (percpu_ref_tryget(&hctx
->queue
->q_usage_counter
)) {
2976 while (blk_mq_hctx_has_requests(hctx
))
2978 percpu_ref_put(&hctx
->queue
->q_usage_counter
);
2984 static int blk_mq_hctx_notify_online(unsigned int cpu
, struct hlist_node
*node
)
2986 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
2987 struct blk_mq_hw_ctx
, cpuhp_online
);
2989 if (cpumask_test_cpu(cpu
, hctx
->cpumask
))
2990 clear_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
2995 * 'cpu' is going away. splice any existing rq_list entries from this
2996 * software queue to the hw queue dispatch list, and ensure that it
2999 static int blk_mq_hctx_notify_dead(unsigned int cpu
, struct hlist_node
*node
)
3001 struct blk_mq_hw_ctx
*hctx
;
3002 struct blk_mq_ctx
*ctx
;
3004 enum hctx_type type
;
3006 hctx
= hlist_entry_safe(node
, struct blk_mq_hw_ctx
, cpuhp_dead
);
3007 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
))
3010 ctx
= __blk_mq_get_ctx(hctx
->queue
, cpu
);
3013 spin_lock(&ctx
->lock
);
3014 if (!list_empty(&ctx
->rq_lists
[type
])) {
3015 list_splice_init(&ctx
->rq_lists
[type
], &tmp
);
3016 blk_mq_hctx_clear_pending(hctx
, ctx
);
3018 spin_unlock(&ctx
->lock
);
3020 if (list_empty(&tmp
))
3023 spin_lock(&hctx
->lock
);
3024 list_splice_tail_init(&tmp
, &hctx
->dispatch
);
3025 spin_unlock(&hctx
->lock
);
3027 blk_mq_run_hw_queue(hctx
, true);
3031 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx
*hctx
)
3033 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
3034 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
3035 &hctx
->cpuhp_online
);
3036 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD
,
3041 * Before freeing hw queue, clearing the flush request reference in
3042 * tags->rqs[] for avoiding potential UAF.
3044 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags
*tags
,
3045 unsigned int queue_depth
, struct request
*flush_rq
)
3048 unsigned long flags
;
3050 /* The hw queue may not be mapped yet */
3054 WARN_ON_ONCE(refcount_read(&flush_rq
->ref
) != 0);
3056 for (i
= 0; i
< queue_depth
; i
++)
3057 cmpxchg(&tags
->rqs
[i
], flush_rq
, NULL
);
3060 * Wait until all pending iteration is done.
3062 * Request reference is cleared and it is guaranteed to be observed
3063 * after the ->lock is released.
3065 spin_lock_irqsave(&tags
->lock
, flags
);
3066 spin_unlock_irqrestore(&tags
->lock
, flags
);
3069 /* hctx->ctxs will be freed in queue's release handler */
3070 static void blk_mq_exit_hctx(struct request_queue
*q
,
3071 struct blk_mq_tag_set
*set
,
3072 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
3074 struct request
*flush_rq
= hctx
->fq
->flush_rq
;
3076 if (blk_mq_hw_queue_mapped(hctx
))
3077 blk_mq_tag_idle(hctx
);
3079 blk_mq_clear_flush_rq_mapping(set
->tags
[hctx_idx
],
3080 set
->queue_depth
, flush_rq
);
3081 if (set
->ops
->exit_request
)
3082 set
->ops
->exit_request(set
, flush_rq
, hctx_idx
);
3084 if (set
->ops
->exit_hctx
)
3085 set
->ops
->exit_hctx(hctx
, hctx_idx
);
3087 blk_mq_remove_cpuhp(hctx
);
3089 spin_lock(&q
->unused_hctx_lock
);
3090 list_add(&hctx
->hctx_list
, &q
->unused_hctx_list
);
3091 spin_unlock(&q
->unused_hctx_lock
);
3094 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
3095 struct blk_mq_tag_set
*set
, int nr_queue
)
3097 struct blk_mq_hw_ctx
*hctx
;
3100 queue_for_each_hw_ctx(q
, hctx
, i
) {
3103 blk_mq_debugfs_unregister_hctx(hctx
);
3104 blk_mq_exit_hctx(q
, set
, hctx
, i
);
3108 static int blk_mq_hw_ctx_size(struct blk_mq_tag_set
*tag_set
)
3110 int hw_ctx_size
= sizeof(struct blk_mq_hw_ctx
);
3112 BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx
, srcu
),
3113 __alignof__(struct blk_mq_hw_ctx
)) !=
3114 sizeof(struct blk_mq_hw_ctx
));
3116 if (tag_set
->flags
& BLK_MQ_F_BLOCKING
)
3117 hw_ctx_size
+= sizeof(struct srcu_struct
);
3122 static int blk_mq_init_hctx(struct request_queue
*q
,
3123 struct blk_mq_tag_set
*set
,
3124 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
3126 hctx
->queue_num
= hctx_idx
;
3128 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
3129 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
3130 &hctx
->cpuhp_online
);
3131 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD
, &hctx
->cpuhp_dead
);
3133 hctx
->tags
= set
->tags
[hctx_idx
];
3135 if (set
->ops
->init_hctx
&&
3136 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
3137 goto unregister_cpu_notifier
;
3139 if (blk_mq_init_request(set
, hctx
->fq
->flush_rq
, hctx_idx
,
3145 if (set
->ops
->exit_hctx
)
3146 set
->ops
->exit_hctx(hctx
, hctx_idx
);
3147 unregister_cpu_notifier
:
3148 blk_mq_remove_cpuhp(hctx
);
3152 static struct blk_mq_hw_ctx
*
3153 blk_mq_alloc_hctx(struct request_queue
*q
, struct blk_mq_tag_set
*set
,
3156 struct blk_mq_hw_ctx
*hctx
;
3157 gfp_t gfp
= GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
;
3159 hctx
= kzalloc_node(blk_mq_hw_ctx_size(set
), gfp
, node
);
3161 goto fail_alloc_hctx
;
3163 if (!zalloc_cpumask_var_node(&hctx
->cpumask
, gfp
, node
))
3166 atomic_set(&hctx
->nr_active
, 0);
3167 if (node
== NUMA_NO_NODE
)
3168 node
= set
->numa_node
;
3169 hctx
->numa_node
= node
;
3171 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
3172 spin_lock_init(&hctx
->lock
);
3173 INIT_LIST_HEAD(&hctx
->dispatch
);
3175 hctx
->flags
= set
->flags
& ~BLK_MQ_F_TAG_QUEUE_SHARED
;
3177 INIT_LIST_HEAD(&hctx
->hctx_list
);
3180 * Allocate space for all possible cpus to avoid allocation at
3183 hctx
->ctxs
= kmalloc_array_node(nr_cpu_ids
, sizeof(void *),
3188 if (sbitmap_init_node(&hctx
->ctx_map
, nr_cpu_ids
, ilog2(8),
3189 gfp
, node
, false, false))
3193 spin_lock_init(&hctx
->dispatch_wait_lock
);
3194 init_waitqueue_func_entry(&hctx
->dispatch_wait
, blk_mq_dispatch_wake
);
3195 INIT_LIST_HEAD(&hctx
->dispatch_wait
.entry
);
3197 hctx
->fq
= blk_alloc_flush_queue(hctx
->numa_node
, set
->cmd_size
, gfp
);
3201 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
3202 init_srcu_struct(hctx
->srcu
);
3203 blk_mq_hctx_kobj_init(hctx
);
3208 sbitmap_free(&hctx
->ctx_map
);
3212 free_cpumask_var(hctx
->cpumask
);
3219 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
3220 unsigned int nr_hw_queues
)
3222 struct blk_mq_tag_set
*set
= q
->tag_set
;
3225 for_each_possible_cpu(i
) {
3226 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
3227 struct blk_mq_hw_ctx
*hctx
;
3231 spin_lock_init(&__ctx
->lock
);
3232 for (k
= HCTX_TYPE_DEFAULT
; k
< HCTX_MAX_TYPES
; k
++)
3233 INIT_LIST_HEAD(&__ctx
->rq_lists
[k
]);
3238 * Set local node, IFF we have more than one hw queue. If
3239 * not, we remain on the home node of the device
3241 for (j
= 0; j
< set
->nr_maps
; j
++) {
3242 hctx
= blk_mq_map_queue_type(q
, j
, i
);
3243 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
3244 hctx
->numa_node
= cpu_to_node(i
);
3249 struct blk_mq_tags
*blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set
*set
,
3250 unsigned int hctx_idx
,
3253 struct blk_mq_tags
*tags
;
3256 tags
= blk_mq_alloc_rq_map(set
, hctx_idx
, depth
, set
->reserved_tags
);
3260 ret
= blk_mq_alloc_rqs(set
, tags
, hctx_idx
, depth
);
3262 blk_mq_free_rq_map(tags
);
3269 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set
*set
,
3272 if (blk_mq_is_shared_tags(set
->flags
)) {
3273 set
->tags
[hctx_idx
] = set
->shared_tags
;
3278 set
->tags
[hctx_idx
] = blk_mq_alloc_map_and_rqs(set
, hctx_idx
,
3281 return set
->tags
[hctx_idx
];
3284 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set
*set
,
3285 struct blk_mq_tags
*tags
,
3286 unsigned int hctx_idx
)
3289 blk_mq_free_rqs(set
, tags
, hctx_idx
);
3290 blk_mq_free_rq_map(tags
);
3294 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set
*set
,
3295 unsigned int hctx_idx
)
3297 if (!blk_mq_is_shared_tags(set
->flags
))
3298 blk_mq_free_map_and_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
);
3300 set
->tags
[hctx_idx
] = NULL
;
3303 static void blk_mq_map_swqueue(struct request_queue
*q
)
3305 unsigned int i
, j
, hctx_idx
;
3306 struct blk_mq_hw_ctx
*hctx
;
3307 struct blk_mq_ctx
*ctx
;
3308 struct blk_mq_tag_set
*set
= q
->tag_set
;
3310 queue_for_each_hw_ctx(q
, hctx
, i
) {
3311 cpumask_clear(hctx
->cpumask
);
3313 hctx
->dispatch_from
= NULL
;
3317 * Map software to hardware queues.
3319 * If the cpu isn't present, the cpu is mapped to first hctx.
3321 for_each_possible_cpu(i
) {
3323 ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
3324 for (j
= 0; j
< set
->nr_maps
; j
++) {
3325 if (!set
->map
[j
].nr_queues
) {
3326 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
3327 HCTX_TYPE_DEFAULT
, i
);
3330 hctx_idx
= set
->map
[j
].mq_map
[i
];
3331 /* unmapped hw queue can be remapped after CPU topo changed */
3332 if (!set
->tags
[hctx_idx
] &&
3333 !__blk_mq_alloc_map_and_rqs(set
, hctx_idx
)) {
3335 * If tags initialization fail for some hctx,
3336 * that hctx won't be brought online. In this
3337 * case, remap the current ctx to hctx[0] which
3338 * is guaranteed to always have tags allocated
3340 set
->map
[j
].mq_map
[i
] = 0;
3343 hctx
= blk_mq_map_queue_type(q
, j
, i
);
3344 ctx
->hctxs
[j
] = hctx
;
3346 * If the CPU is already set in the mask, then we've
3347 * mapped this one already. This can happen if
3348 * devices share queues across queue maps.
3350 if (cpumask_test_cpu(i
, hctx
->cpumask
))
3353 cpumask_set_cpu(i
, hctx
->cpumask
);
3355 ctx
->index_hw
[hctx
->type
] = hctx
->nr_ctx
;
3356 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
3359 * If the nr_ctx type overflows, we have exceeded the
3360 * amount of sw queues we can support.
3362 BUG_ON(!hctx
->nr_ctx
);
3365 for (; j
< HCTX_MAX_TYPES
; j
++)
3366 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
3367 HCTX_TYPE_DEFAULT
, i
);
3370 queue_for_each_hw_ctx(q
, hctx
, i
) {
3372 * If no software queues are mapped to this hardware queue,
3373 * disable it and free the request entries.
3375 if (!hctx
->nr_ctx
) {
3376 /* Never unmap queue 0. We need it as a
3377 * fallback in case of a new remap fails
3381 __blk_mq_free_map_and_rqs(set
, i
);
3387 hctx
->tags
= set
->tags
[i
];
3388 WARN_ON(!hctx
->tags
);
3391 * Set the map size to the number of mapped software queues.
3392 * This is more accurate and more efficient than looping
3393 * over all possibly mapped software queues.
3395 sbitmap_resize(&hctx
->ctx_map
, hctx
->nr_ctx
);
3398 * Initialize batch roundrobin counts
3400 hctx
->next_cpu
= blk_mq_first_mapped_cpu(hctx
);
3401 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
3406 * Caller needs to ensure that we're either frozen/quiesced, or that
3407 * the queue isn't live yet.
3409 static void queue_set_hctx_shared(struct request_queue
*q
, bool shared
)
3411 struct blk_mq_hw_ctx
*hctx
;
3414 queue_for_each_hw_ctx(q
, hctx
, i
) {
3416 hctx
->flags
|= BLK_MQ_F_TAG_QUEUE_SHARED
;
3418 blk_mq_tag_idle(hctx
);
3419 hctx
->flags
&= ~BLK_MQ_F_TAG_QUEUE_SHARED
;
3424 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set
*set
,
3427 struct request_queue
*q
;
3429 lockdep_assert_held(&set
->tag_list_lock
);
3431 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3432 blk_mq_freeze_queue(q
);
3433 queue_set_hctx_shared(q
, shared
);
3434 blk_mq_unfreeze_queue(q
);
3438 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
3440 struct blk_mq_tag_set
*set
= q
->tag_set
;
3442 mutex_lock(&set
->tag_list_lock
);
3443 list_del(&q
->tag_set_list
);
3444 if (list_is_singular(&set
->tag_list
)) {
3445 /* just transitioned to unshared */
3446 set
->flags
&= ~BLK_MQ_F_TAG_QUEUE_SHARED
;
3447 /* update existing queue */
3448 blk_mq_update_tag_set_shared(set
, false);
3450 mutex_unlock(&set
->tag_list_lock
);
3451 INIT_LIST_HEAD(&q
->tag_set_list
);
3454 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
3455 struct request_queue
*q
)
3457 mutex_lock(&set
->tag_list_lock
);
3460 * Check to see if we're transitioning to shared (from 1 to 2 queues).
3462 if (!list_empty(&set
->tag_list
) &&
3463 !(set
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)) {
3464 set
->flags
|= BLK_MQ_F_TAG_QUEUE_SHARED
;
3465 /* update existing queue */
3466 blk_mq_update_tag_set_shared(set
, true);
3468 if (set
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)
3469 queue_set_hctx_shared(q
, true);
3470 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
3472 mutex_unlock(&set
->tag_list_lock
);
3475 /* All allocations will be freed in release handler of q->mq_kobj */
3476 static int blk_mq_alloc_ctxs(struct request_queue
*q
)
3478 struct blk_mq_ctxs
*ctxs
;
3481 ctxs
= kzalloc(sizeof(*ctxs
), GFP_KERNEL
);
3485 ctxs
->queue_ctx
= alloc_percpu(struct blk_mq_ctx
);
3486 if (!ctxs
->queue_ctx
)
3489 for_each_possible_cpu(cpu
) {
3490 struct blk_mq_ctx
*ctx
= per_cpu_ptr(ctxs
->queue_ctx
, cpu
);
3494 q
->mq_kobj
= &ctxs
->kobj
;
3495 q
->queue_ctx
= ctxs
->queue_ctx
;
3504 * It is the actual release handler for mq, but we do it from
3505 * request queue's release handler for avoiding use-after-free
3506 * and headache because q->mq_kobj shouldn't have been introduced,
3507 * but we can't group ctx/kctx kobj without it.
3509 void blk_mq_release(struct request_queue
*q
)
3511 struct blk_mq_hw_ctx
*hctx
, *next
;
3514 queue_for_each_hw_ctx(q
, hctx
, i
)
3515 WARN_ON_ONCE(hctx
&& list_empty(&hctx
->hctx_list
));
3517 /* all hctx are in .unused_hctx_list now */
3518 list_for_each_entry_safe(hctx
, next
, &q
->unused_hctx_list
, hctx_list
) {
3519 list_del_init(&hctx
->hctx_list
);
3520 kobject_put(&hctx
->kobj
);
3523 kfree(q
->queue_hw_ctx
);
3526 * release .mq_kobj and sw queue's kobject now because
3527 * both share lifetime with request queue.
3529 blk_mq_sysfs_deinit(q
);
3532 static struct request_queue
*blk_mq_init_queue_data(struct blk_mq_tag_set
*set
,
3535 struct request_queue
*q
;
3538 q
= blk_alloc_queue(set
->numa_node
);
3540 return ERR_PTR(-ENOMEM
);
3541 q
->queuedata
= queuedata
;
3542 ret
= blk_mq_init_allocated_queue(set
, q
);
3544 blk_cleanup_queue(q
);
3545 return ERR_PTR(ret
);
3550 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
3552 return blk_mq_init_queue_data(set
, NULL
);
3554 EXPORT_SYMBOL(blk_mq_init_queue
);
3556 struct gendisk
*__blk_mq_alloc_disk(struct blk_mq_tag_set
*set
, void *queuedata
,
3557 struct lock_class_key
*lkclass
)
3559 struct request_queue
*q
;
3560 struct gendisk
*disk
;
3562 q
= blk_mq_init_queue_data(set
, queuedata
);
3566 disk
= __alloc_disk_node(q
, set
->numa_node
, lkclass
);
3568 blk_cleanup_queue(q
);
3569 return ERR_PTR(-ENOMEM
);
3573 EXPORT_SYMBOL(__blk_mq_alloc_disk
);
3575 static struct blk_mq_hw_ctx
*blk_mq_alloc_and_init_hctx(
3576 struct blk_mq_tag_set
*set
, struct request_queue
*q
,
3577 int hctx_idx
, int node
)
3579 struct blk_mq_hw_ctx
*hctx
= NULL
, *tmp
;
3581 /* reuse dead hctx first */
3582 spin_lock(&q
->unused_hctx_lock
);
3583 list_for_each_entry(tmp
, &q
->unused_hctx_list
, hctx_list
) {
3584 if (tmp
->numa_node
== node
) {
3590 list_del_init(&hctx
->hctx_list
);
3591 spin_unlock(&q
->unused_hctx_lock
);
3594 hctx
= blk_mq_alloc_hctx(q
, set
, node
);
3598 if (blk_mq_init_hctx(q
, set
, hctx
, hctx_idx
))
3604 kobject_put(&hctx
->kobj
);
3609 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set
*set
,
3610 struct request_queue
*q
)
3613 struct blk_mq_hw_ctx
**hctxs
= q
->queue_hw_ctx
;
3615 if (q
->nr_hw_queues
< set
->nr_hw_queues
) {
3616 struct blk_mq_hw_ctx
**new_hctxs
;
3618 new_hctxs
= kcalloc_node(set
->nr_hw_queues
,
3619 sizeof(*new_hctxs
), GFP_KERNEL
,
3624 memcpy(new_hctxs
, hctxs
, q
->nr_hw_queues
*
3626 q
->queue_hw_ctx
= new_hctxs
;
3631 /* protect against switching io scheduler */
3632 mutex_lock(&q
->sysfs_lock
);
3633 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
3635 struct blk_mq_hw_ctx
*hctx
;
3637 node
= blk_mq_hw_queue_to_node(&set
->map
[HCTX_TYPE_DEFAULT
], i
);
3639 * If the hw queue has been mapped to another numa node,
3640 * we need to realloc the hctx. If allocation fails, fallback
3641 * to use the previous one.
3643 if (hctxs
[i
] && (hctxs
[i
]->numa_node
== node
))
3646 hctx
= blk_mq_alloc_and_init_hctx(set
, q
, i
, node
);
3649 blk_mq_exit_hctx(q
, set
, hctxs
[i
], i
);
3653 pr_warn("Allocate new hctx on node %d fails,\
3654 fallback to previous one on node %d\n",
3655 node
, hctxs
[i
]->numa_node
);
3661 * Increasing nr_hw_queues fails. Free the newly allocated
3662 * hctxs and keep the previous q->nr_hw_queues.
3664 if (i
!= set
->nr_hw_queues
) {
3665 j
= q
->nr_hw_queues
;
3669 end
= q
->nr_hw_queues
;
3670 q
->nr_hw_queues
= set
->nr_hw_queues
;
3673 for (; j
< end
; j
++) {
3674 struct blk_mq_hw_ctx
*hctx
= hctxs
[j
];
3677 blk_mq_exit_hctx(q
, set
, hctx
, j
);
3681 mutex_unlock(&q
->sysfs_lock
);
3684 int blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
3685 struct request_queue
*q
)
3687 /* mark the queue as mq asap */
3688 q
->mq_ops
= set
->ops
;
3690 q
->poll_cb
= blk_stat_alloc_callback(blk_mq_poll_stats_fn
,
3691 blk_mq_poll_stats_bkt
,
3692 BLK_MQ_POLL_STATS_BKTS
, q
);
3696 if (blk_mq_alloc_ctxs(q
))
3699 /* init q->mq_kobj and sw queues' kobjects */
3700 blk_mq_sysfs_init(q
);
3702 INIT_LIST_HEAD(&q
->unused_hctx_list
);
3703 spin_lock_init(&q
->unused_hctx_lock
);
3705 blk_mq_realloc_hw_ctxs(set
, q
);
3706 if (!q
->nr_hw_queues
)
3709 INIT_WORK(&q
->timeout_work
, blk_mq_timeout_work
);
3710 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
3714 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
3715 if (set
->nr_maps
> HCTX_TYPE_POLL
&&
3716 set
->map
[HCTX_TYPE_POLL
].nr_queues
)
3717 blk_queue_flag_set(QUEUE_FLAG_POLL
, q
);
3719 INIT_DELAYED_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
3720 INIT_LIST_HEAD(&q
->requeue_list
);
3721 spin_lock_init(&q
->requeue_lock
);
3723 q
->nr_requests
= set
->queue_depth
;
3726 * Default to classic polling
3728 q
->poll_nsec
= BLK_MQ_POLL_CLASSIC
;
3730 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
3731 blk_mq_add_queue_tag_set(set
, q
);
3732 blk_mq_map_swqueue(q
);
3736 kfree(q
->queue_hw_ctx
);
3737 q
->nr_hw_queues
= 0;
3738 blk_mq_sysfs_deinit(q
);
3740 blk_stat_free_callback(q
->poll_cb
);
3746 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
3748 /* tags can _not_ be used after returning from blk_mq_exit_queue */
3749 void blk_mq_exit_queue(struct request_queue
*q
)
3751 struct blk_mq_tag_set
*set
= q
->tag_set
;
3753 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
3754 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
3755 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
3756 blk_mq_del_queue_tag_set(q
);
3759 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
3763 if (blk_mq_is_shared_tags(set
->flags
)) {
3764 set
->shared_tags
= blk_mq_alloc_map_and_rqs(set
,
3767 if (!set
->shared_tags
)
3771 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
3772 if (!__blk_mq_alloc_map_and_rqs(set
, i
))
3781 __blk_mq_free_map_and_rqs(set
, i
);
3783 if (blk_mq_is_shared_tags(set
->flags
)) {
3784 blk_mq_free_map_and_rqs(set
, set
->shared_tags
,
3785 BLK_MQ_NO_HCTX_IDX
);
3792 * Allocate the request maps associated with this tag_set. Note that this
3793 * may reduce the depth asked for, if memory is tight. set->queue_depth
3794 * will be updated to reflect the allocated depth.
3796 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set
*set
)
3801 depth
= set
->queue_depth
;
3803 err
= __blk_mq_alloc_rq_maps(set
);
3807 set
->queue_depth
>>= 1;
3808 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
3812 } while (set
->queue_depth
);
3814 if (!set
->queue_depth
|| err
) {
3815 pr_err("blk-mq: failed to allocate request map\n");
3819 if (depth
!= set
->queue_depth
)
3820 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
3821 depth
, set
->queue_depth
);
3826 static int blk_mq_update_queue_map(struct blk_mq_tag_set
*set
)
3829 * blk_mq_map_queues() and multiple .map_queues() implementations
3830 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
3831 * number of hardware queues.
3833 if (set
->nr_maps
== 1)
3834 set
->map
[HCTX_TYPE_DEFAULT
].nr_queues
= set
->nr_hw_queues
;
3836 if (set
->ops
->map_queues
&& !is_kdump_kernel()) {
3840 * transport .map_queues is usually done in the following
3843 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
3844 * mask = get_cpu_mask(queue)
3845 * for_each_cpu(cpu, mask)
3846 * set->map[x].mq_map[cpu] = queue;
3849 * When we need to remap, the table has to be cleared for
3850 * killing stale mapping since one CPU may not be mapped
3853 for (i
= 0; i
< set
->nr_maps
; i
++)
3854 blk_mq_clear_mq_map(&set
->map
[i
]);
3856 return set
->ops
->map_queues(set
);
3858 BUG_ON(set
->nr_maps
> 1);
3859 return blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
3863 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set
*set
,
3864 int cur_nr_hw_queues
, int new_nr_hw_queues
)
3866 struct blk_mq_tags
**new_tags
;
3868 if (cur_nr_hw_queues
>= new_nr_hw_queues
)
3871 new_tags
= kcalloc_node(new_nr_hw_queues
, sizeof(struct blk_mq_tags
*),
3872 GFP_KERNEL
, set
->numa_node
);
3877 memcpy(new_tags
, set
->tags
, cur_nr_hw_queues
*
3878 sizeof(*set
->tags
));
3880 set
->tags
= new_tags
;
3881 set
->nr_hw_queues
= new_nr_hw_queues
;
3886 static int blk_mq_alloc_tag_set_tags(struct blk_mq_tag_set
*set
,
3887 int new_nr_hw_queues
)
3889 return blk_mq_realloc_tag_set_tags(set
, 0, new_nr_hw_queues
);
3893 * Alloc a tag set to be associated with one or more request queues.
3894 * May fail with EINVAL for various error conditions. May adjust the
3895 * requested depth down, if it's too large. In that case, the set
3896 * value will be stored in set->queue_depth.
3898 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
3902 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
3904 if (!set
->nr_hw_queues
)
3906 if (!set
->queue_depth
)
3908 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
3911 if (!set
->ops
->queue_rq
)
3914 if (!set
->ops
->get_budget
^ !set
->ops
->put_budget
)
3917 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
3918 pr_info("blk-mq: reduced tag depth to %u\n",
3920 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
3925 else if (set
->nr_maps
> HCTX_MAX_TYPES
)
3929 * If a crashdump is active, then we are potentially in a very
3930 * memory constrained environment. Limit us to 1 queue and
3931 * 64 tags to prevent using too much memory.
3933 if (is_kdump_kernel()) {
3934 set
->nr_hw_queues
= 1;
3936 set
->queue_depth
= min(64U, set
->queue_depth
);
3939 * There is no use for more h/w queues than cpus if we just have
3942 if (set
->nr_maps
== 1 && set
->nr_hw_queues
> nr_cpu_ids
)
3943 set
->nr_hw_queues
= nr_cpu_ids
;
3945 if (blk_mq_alloc_tag_set_tags(set
, set
->nr_hw_queues
) < 0)
3949 for (i
= 0; i
< set
->nr_maps
; i
++) {
3950 set
->map
[i
].mq_map
= kcalloc_node(nr_cpu_ids
,
3951 sizeof(set
->map
[i
].mq_map
[0]),
3952 GFP_KERNEL
, set
->numa_node
);
3953 if (!set
->map
[i
].mq_map
)
3954 goto out_free_mq_map
;
3955 set
->map
[i
].nr_queues
= is_kdump_kernel() ? 1 : set
->nr_hw_queues
;
3958 ret
= blk_mq_update_queue_map(set
);
3960 goto out_free_mq_map
;
3962 ret
= blk_mq_alloc_set_map_and_rqs(set
);
3964 goto out_free_mq_map
;
3966 mutex_init(&set
->tag_list_lock
);
3967 INIT_LIST_HEAD(&set
->tag_list
);
3972 for (i
= 0; i
< set
->nr_maps
; i
++) {
3973 kfree(set
->map
[i
].mq_map
);
3974 set
->map
[i
].mq_map
= NULL
;
3980 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
3982 /* allocate and initialize a tagset for a simple single-queue device */
3983 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set
*set
,
3984 const struct blk_mq_ops
*ops
, unsigned int queue_depth
,
3985 unsigned int set_flags
)
3987 memset(set
, 0, sizeof(*set
));
3989 set
->nr_hw_queues
= 1;
3991 set
->queue_depth
= queue_depth
;
3992 set
->numa_node
= NUMA_NO_NODE
;
3993 set
->flags
= set_flags
;
3994 return blk_mq_alloc_tag_set(set
);
3996 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set
);
3998 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
4002 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
4003 __blk_mq_free_map_and_rqs(set
, i
);
4005 if (blk_mq_is_shared_tags(set
->flags
)) {
4006 blk_mq_free_map_and_rqs(set
, set
->shared_tags
,
4007 BLK_MQ_NO_HCTX_IDX
);
4010 for (j
= 0; j
< set
->nr_maps
; j
++) {
4011 kfree(set
->map
[j
].mq_map
);
4012 set
->map
[j
].mq_map
= NULL
;
4018 EXPORT_SYMBOL(blk_mq_free_tag_set
);
4020 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
4022 struct blk_mq_tag_set
*set
= q
->tag_set
;
4023 struct blk_mq_hw_ctx
*hctx
;
4029 if (q
->nr_requests
== nr
)
4032 blk_mq_freeze_queue(q
);
4033 blk_mq_quiesce_queue(q
);
4036 queue_for_each_hw_ctx(q
, hctx
, i
) {
4040 * If we're using an MQ scheduler, just update the scheduler
4041 * queue depth. This is similar to what the old code would do.
4043 if (hctx
->sched_tags
) {
4044 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->sched_tags
,
4047 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->tags
, nr
,
4052 if (q
->elevator
&& q
->elevator
->type
->ops
.depth_updated
)
4053 q
->elevator
->type
->ops
.depth_updated(hctx
);
4056 q
->nr_requests
= nr
;
4057 if (blk_mq_is_shared_tags(set
->flags
)) {
4059 blk_mq_tag_update_sched_shared_tags(q
);
4061 blk_mq_tag_resize_shared_tags(set
, nr
);
4065 blk_mq_unquiesce_queue(q
);
4066 blk_mq_unfreeze_queue(q
);
4072 * request_queue and elevator_type pair.
4073 * It is just used by __blk_mq_update_nr_hw_queues to cache
4074 * the elevator_type associated with a request_queue.
4076 struct blk_mq_qe_pair
{
4077 struct list_head node
;
4078 struct request_queue
*q
;
4079 struct elevator_type
*type
;
4083 * Cache the elevator_type in qe pair list and switch the
4084 * io scheduler to 'none'
4086 static bool blk_mq_elv_switch_none(struct list_head
*head
,
4087 struct request_queue
*q
)
4089 struct blk_mq_qe_pair
*qe
;
4094 qe
= kmalloc(sizeof(*qe
), GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
);
4098 INIT_LIST_HEAD(&qe
->node
);
4100 qe
->type
= q
->elevator
->type
;
4101 list_add(&qe
->node
, head
);
4103 mutex_lock(&q
->sysfs_lock
);
4105 * After elevator_switch_mq, the previous elevator_queue will be
4106 * released by elevator_release. The reference of the io scheduler
4107 * module get by elevator_get will also be put. So we need to get
4108 * a reference of the io scheduler module here to prevent it to be
4111 __module_get(qe
->type
->elevator_owner
);
4112 elevator_switch_mq(q
, NULL
);
4113 mutex_unlock(&q
->sysfs_lock
);
4118 static void blk_mq_elv_switch_back(struct list_head
*head
,
4119 struct request_queue
*q
)
4121 struct blk_mq_qe_pair
*qe
;
4122 struct elevator_type
*t
= NULL
;
4124 list_for_each_entry(qe
, head
, node
)
4133 list_del(&qe
->node
);
4136 mutex_lock(&q
->sysfs_lock
);
4137 elevator_switch_mq(q
, t
);
4138 mutex_unlock(&q
->sysfs_lock
);
4141 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
,
4144 struct request_queue
*q
;
4146 int prev_nr_hw_queues
;
4148 lockdep_assert_held(&set
->tag_list_lock
);
4150 if (set
->nr_maps
== 1 && nr_hw_queues
> nr_cpu_ids
)
4151 nr_hw_queues
= nr_cpu_ids
;
4152 if (nr_hw_queues
< 1)
4154 if (set
->nr_maps
== 1 && nr_hw_queues
== set
->nr_hw_queues
)
4157 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4158 blk_mq_freeze_queue(q
);
4160 * Switch IO scheduler to 'none', cleaning up the data associated
4161 * with the previous scheduler. We will switch back once we are done
4162 * updating the new sw to hw queue mappings.
4164 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4165 if (!blk_mq_elv_switch_none(&head
, q
))
4168 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
4169 blk_mq_debugfs_unregister_hctxs(q
);
4170 blk_mq_sysfs_unregister(q
);
4173 prev_nr_hw_queues
= set
->nr_hw_queues
;
4174 if (blk_mq_realloc_tag_set_tags(set
, set
->nr_hw_queues
, nr_hw_queues
) <
4178 set
->nr_hw_queues
= nr_hw_queues
;
4180 blk_mq_update_queue_map(set
);
4181 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
4182 blk_mq_realloc_hw_ctxs(set
, q
);
4183 if (q
->nr_hw_queues
!= set
->nr_hw_queues
) {
4184 int i
= prev_nr_hw_queues
;
4186 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4187 nr_hw_queues
, prev_nr_hw_queues
);
4188 for (; i
< set
->nr_hw_queues
; i
++)
4189 __blk_mq_free_map_and_rqs(set
, i
);
4191 set
->nr_hw_queues
= prev_nr_hw_queues
;
4192 blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
4195 blk_mq_map_swqueue(q
);
4199 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
4200 blk_mq_sysfs_register(q
);
4201 blk_mq_debugfs_register_hctxs(q
);
4205 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4206 blk_mq_elv_switch_back(&head
, q
);
4208 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4209 blk_mq_unfreeze_queue(q
);
4212 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
, int nr_hw_queues
)
4214 mutex_lock(&set
->tag_list_lock
);
4215 __blk_mq_update_nr_hw_queues(set
, nr_hw_queues
);
4216 mutex_unlock(&set
->tag_list_lock
);
4218 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues
);
4220 /* Enable polling stats and return whether they were already enabled. */
4221 static bool blk_poll_stats_enable(struct request_queue
*q
)
4223 if (test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
4224 blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS
, q
))
4226 blk_stat_add_callback(q
, q
->poll_cb
);
4230 static void blk_mq_poll_stats_start(struct request_queue
*q
)
4233 * We don't arm the callback if polling stats are not enabled or the
4234 * callback is already active.
4236 if (!test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
4237 blk_stat_is_active(q
->poll_cb
))
4240 blk_stat_activate_msecs(q
->poll_cb
, 100);
4243 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
)
4245 struct request_queue
*q
= cb
->data
;
4248 for (bucket
= 0; bucket
< BLK_MQ_POLL_STATS_BKTS
; bucket
++) {
4249 if (cb
->stat
[bucket
].nr_samples
)
4250 q
->poll_stat
[bucket
] = cb
->stat
[bucket
];
4254 static unsigned long blk_mq_poll_nsecs(struct request_queue
*q
,
4257 unsigned long ret
= 0;
4261 * If stats collection isn't on, don't sleep but turn it on for
4264 if (!blk_poll_stats_enable(q
))
4268 * As an optimistic guess, use half of the mean service time
4269 * for this type of request. We can (and should) make this smarter.
4270 * For instance, if the completion latencies are tight, we can
4271 * get closer than just half the mean. This is especially
4272 * important on devices where the completion latencies are longer
4273 * than ~10 usec. We do use the stats for the relevant IO size
4274 * if available which does lead to better estimates.
4276 bucket
= blk_mq_poll_stats_bkt(rq
);
4280 if (q
->poll_stat
[bucket
].nr_samples
)
4281 ret
= (q
->poll_stat
[bucket
].mean
+ 1) / 2;
4286 static bool blk_mq_poll_hybrid(struct request_queue
*q
, blk_qc_t qc
)
4288 struct blk_mq_hw_ctx
*hctx
= blk_qc_to_hctx(q
, qc
);
4289 struct request
*rq
= blk_qc_to_rq(hctx
, qc
);
4290 struct hrtimer_sleeper hs
;
4291 enum hrtimer_mode mode
;
4296 * If a request has completed on queue that uses an I/O scheduler, we
4297 * won't get back a request from blk_qc_to_rq.
4299 if (!rq
|| (rq
->rq_flags
& RQF_MQ_POLL_SLEPT
))
4303 * If we get here, hybrid polling is enabled. Hence poll_nsec can be:
4305 * 0: use half of prev avg
4306 * >0: use this specific value
4308 if (q
->poll_nsec
> 0)
4309 nsecs
= q
->poll_nsec
;
4311 nsecs
= blk_mq_poll_nsecs(q
, rq
);
4316 rq
->rq_flags
|= RQF_MQ_POLL_SLEPT
;
4319 * This will be replaced with the stats tracking code, using
4320 * 'avg_completion_time / 2' as the pre-sleep target.
4324 mode
= HRTIMER_MODE_REL
;
4325 hrtimer_init_sleeper_on_stack(&hs
, CLOCK_MONOTONIC
, mode
);
4326 hrtimer_set_expires(&hs
.timer
, kt
);
4329 if (blk_mq_rq_state(rq
) == MQ_RQ_COMPLETE
)
4331 set_current_state(TASK_UNINTERRUPTIBLE
);
4332 hrtimer_sleeper_start_expires(&hs
, mode
);
4335 hrtimer_cancel(&hs
.timer
);
4336 mode
= HRTIMER_MODE_ABS
;
4337 } while (hs
.task
&& !signal_pending(current
));
4339 __set_current_state(TASK_RUNNING
);
4340 destroy_hrtimer_on_stack(&hs
.timer
);
4343 * If we sleep, have the caller restart the poll loop to reset the
4344 * state. Like for the other success return cases, the caller is
4345 * responsible for checking if the IO completed. If the IO isn't
4346 * complete, we'll get called again and will go straight to the busy
4352 static int blk_mq_poll_classic(struct request_queue
*q
, blk_qc_t cookie
,
4353 struct io_comp_batch
*iob
, unsigned int flags
)
4355 struct blk_mq_hw_ctx
*hctx
= blk_qc_to_hctx(q
, cookie
);
4356 long state
= get_current_state();
4360 ret
= q
->mq_ops
->poll(hctx
, iob
);
4362 __set_current_state(TASK_RUNNING
);
4366 if (signal_pending_state(state
, current
))
4367 __set_current_state(TASK_RUNNING
);
4368 if (task_is_running(current
))
4371 if (ret
< 0 || (flags
& BLK_POLL_ONESHOT
))
4374 } while (!need_resched());
4376 __set_current_state(TASK_RUNNING
);
4380 int blk_mq_poll(struct request_queue
*q
, blk_qc_t cookie
, struct io_comp_batch
*iob
,
4383 if (!(flags
& BLK_POLL_NOSLEEP
) &&
4384 q
->poll_nsec
!= BLK_MQ_POLL_CLASSIC
) {
4385 if (blk_mq_poll_hybrid(q
, cookie
))
4388 return blk_mq_poll_classic(q
, cookie
, iob
, flags
);
4391 unsigned int blk_mq_rq_cpu(struct request
*rq
)
4393 return rq
->mq_ctx
->cpu
;
4395 EXPORT_SYMBOL(blk_mq_rq_cpu
);
4397 static int __init
blk_mq_init(void)
4401 for_each_possible_cpu(i
)
4402 init_llist_head(&per_cpu(blk_cpu_done
, i
));
4403 open_softirq(BLOCK_SOFTIRQ
, blk_done_softirq
);
4405 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD
,
4406 "block/softirq:dead", NULL
,
4407 blk_softirq_cpu_dead
);
4408 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD
, "block/mq:dead", NULL
,
4409 blk_mq_hctx_notify_dead
);
4410 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE
, "block/mq:online",
4411 blk_mq_hctx_notify_online
,
4412 blk_mq_hctx_notify_offline
);
4415 subsys_initcall(blk_mq_init
);