1 // SPDX-License-Identifier: GPL-2.0
3 * Block multiqueue core code
5 * Copyright (C) 2013-2014 Jens Axboe
6 * Copyright (C) 2013-2014 Christoph Hellwig
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/backing-dev.h>
11 #include <linux/bio.h>
12 #include <linux/blkdev.h>
13 #include <linux/blk-integrity.h>
14 #include <linux/kmemleak.h>
16 #include <linux/init.h>
17 #include <linux/slab.h>
18 #include <linux/workqueue.h>
19 #include <linux/smp.h>
20 #include <linux/interrupt.h>
21 #include <linux/llist.h>
22 #include <linux/cpu.h>
23 #include <linux/cache.h>
24 #include <linux/sched/sysctl.h>
25 #include <linux/sched/topology.h>
26 #include <linux/sched/signal.h>
27 #include <linux/delay.h>
28 #include <linux/crash_dump.h>
29 #include <linux/prefetch.h>
30 #include <linux/blk-crypto.h>
31 #include <linux/part_stat.h>
33 #include <trace/events/block.h>
35 #include <linux/blk-mq.h>
36 #include <linux/t10-pi.h>
39 #include "blk-mq-debugfs.h"
40 #include "blk-mq-tag.h"
43 #include "blk-mq-sched.h"
44 #include "blk-rq-qos.h"
46 static DEFINE_PER_CPU(struct llist_head
, blk_cpu_done
);
48 static void blk_mq_poll_stats_start(struct request_queue
*q
);
49 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
);
51 static int blk_mq_poll_stats_bkt(const struct request
*rq
)
53 int ddir
, sectors
, bucket
;
55 ddir
= rq_data_dir(rq
);
56 sectors
= blk_rq_stats_sectors(rq
);
58 bucket
= ddir
+ 2 * ilog2(sectors
);
62 else if (bucket
>= BLK_MQ_POLL_STATS_BKTS
)
63 return ddir
+ BLK_MQ_POLL_STATS_BKTS
- 2;
68 #define BLK_QC_T_SHIFT 16
69 #define BLK_QC_T_INTERNAL (1U << 31)
71 static inline struct blk_mq_hw_ctx
*blk_qc_to_hctx(struct request_queue
*q
,
74 return xa_load(&q
->hctx_table
,
75 (qc
& ~BLK_QC_T_INTERNAL
) >> BLK_QC_T_SHIFT
);
78 static inline struct request
*blk_qc_to_rq(struct blk_mq_hw_ctx
*hctx
,
81 unsigned int tag
= qc
& ((1U << BLK_QC_T_SHIFT
) - 1);
83 if (qc
& BLK_QC_T_INTERNAL
)
84 return blk_mq_tag_to_rq(hctx
->sched_tags
, tag
);
85 return blk_mq_tag_to_rq(hctx
->tags
, tag
);
88 static inline blk_qc_t
blk_rq_to_qc(struct request
*rq
)
90 return (rq
->mq_hctx
->queue_num
<< BLK_QC_T_SHIFT
) |
92 rq
->tag
: (rq
->internal_tag
| BLK_QC_T_INTERNAL
));
96 * Check if any of the ctx, dispatch list or elevator
97 * have pending work in this hardware queue.
99 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
101 return !list_empty_careful(&hctx
->dispatch
) ||
102 sbitmap_any_bit_set(&hctx
->ctx_map
) ||
103 blk_mq_sched_has_work(hctx
);
107 * Mark this ctx as having pending work in this hardware queue
109 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
110 struct blk_mq_ctx
*ctx
)
112 const int bit
= ctx
->index_hw
[hctx
->type
];
114 if (!sbitmap_test_bit(&hctx
->ctx_map
, bit
))
115 sbitmap_set_bit(&hctx
->ctx_map
, bit
);
118 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
119 struct blk_mq_ctx
*ctx
)
121 const int bit
= ctx
->index_hw
[hctx
->type
];
123 sbitmap_clear_bit(&hctx
->ctx_map
, bit
);
127 struct block_device
*part
;
128 unsigned int inflight
[2];
131 static bool blk_mq_check_inflight(struct request
*rq
, void *priv
,
134 struct mq_inflight
*mi
= priv
;
136 if (rq
->part
&& blk_do_io_stat(rq
) &&
137 (!mi
->part
->bd_partno
|| rq
->part
== mi
->part
) &&
138 blk_mq_rq_state(rq
) == MQ_RQ_IN_FLIGHT
)
139 mi
->inflight
[rq_data_dir(rq
)]++;
144 unsigned int blk_mq_in_flight(struct request_queue
*q
,
145 struct block_device
*part
)
147 struct mq_inflight mi
= { .part
= part
};
149 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
151 return mi
.inflight
[0] + mi
.inflight
[1];
154 void blk_mq_in_flight_rw(struct request_queue
*q
, struct block_device
*part
,
155 unsigned int inflight
[2])
157 struct mq_inflight mi
= { .part
= part
};
159 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_inflight
, &mi
);
160 inflight
[0] = mi
.inflight
[0];
161 inflight
[1] = mi
.inflight
[1];
164 void blk_freeze_queue_start(struct request_queue
*q
)
166 mutex_lock(&q
->mq_freeze_lock
);
167 if (++q
->mq_freeze_depth
== 1) {
168 percpu_ref_kill(&q
->q_usage_counter
);
169 mutex_unlock(&q
->mq_freeze_lock
);
171 blk_mq_run_hw_queues(q
, false);
173 mutex_unlock(&q
->mq_freeze_lock
);
176 EXPORT_SYMBOL_GPL(blk_freeze_queue_start
);
178 void blk_mq_freeze_queue_wait(struct request_queue
*q
)
180 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->q_usage_counter
));
182 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait
);
184 int blk_mq_freeze_queue_wait_timeout(struct request_queue
*q
,
185 unsigned long timeout
)
187 return wait_event_timeout(q
->mq_freeze_wq
,
188 percpu_ref_is_zero(&q
->q_usage_counter
),
191 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout
);
194 * Guarantee no request is in use, so we can change any data structure of
195 * the queue afterward.
197 void blk_freeze_queue(struct request_queue
*q
)
200 * In the !blk_mq case we are only calling this to kill the
201 * q_usage_counter, otherwise this increases the freeze depth
202 * and waits for it to return to zero. For this reason there is
203 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
204 * exported to drivers as the only user for unfreeze is blk_mq.
206 blk_freeze_queue_start(q
);
207 blk_mq_freeze_queue_wait(q
);
210 void blk_mq_freeze_queue(struct request_queue
*q
)
213 * ...just an alias to keep freeze and unfreeze actions balanced
214 * in the blk_mq_* namespace
218 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
220 void __blk_mq_unfreeze_queue(struct request_queue
*q
, bool force_atomic
)
222 mutex_lock(&q
->mq_freeze_lock
);
224 q
->q_usage_counter
.data
->force_atomic
= true;
225 q
->mq_freeze_depth
--;
226 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
227 if (!q
->mq_freeze_depth
) {
228 percpu_ref_resurrect(&q
->q_usage_counter
);
229 wake_up_all(&q
->mq_freeze_wq
);
231 mutex_unlock(&q
->mq_freeze_lock
);
234 void blk_mq_unfreeze_queue(struct request_queue
*q
)
236 __blk_mq_unfreeze_queue(q
, false);
238 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
241 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
242 * mpt3sas driver such that this function can be removed.
244 void blk_mq_quiesce_queue_nowait(struct request_queue
*q
)
248 spin_lock_irqsave(&q
->queue_lock
, flags
);
249 if (!q
->quiesce_depth
++)
250 blk_queue_flag_set(QUEUE_FLAG_QUIESCED
, q
);
251 spin_unlock_irqrestore(&q
->queue_lock
, flags
);
253 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait
);
256 * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
259 * Note: it is driver's responsibility for making sure that quiesce has
262 void blk_mq_wait_quiesce_done(struct request_queue
*q
)
264 if (blk_queue_has_srcu(q
))
265 synchronize_srcu(q
->srcu
);
269 EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done
);
272 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
275 * Note: this function does not prevent that the struct request end_io()
276 * callback function is invoked. Once this function is returned, we make
277 * sure no dispatch can happen until the queue is unquiesced via
278 * blk_mq_unquiesce_queue().
280 void blk_mq_quiesce_queue(struct request_queue
*q
)
282 blk_mq_quiesce_queue_nowait(q
);
283 blk_mq_wait_quiesce_done(q
);
285 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue
);
288 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
291 * This function recovers queue into the state before quiescing
292 * which is done by blk_mq_quiesce_queue.
294 void blk_mq_unquiesce_queue(struct request_queue
*q
)
297 bool run_queue
= false;
299 spin_lock_irqsave(&q
->queue_lock
, flags
);
300 if (WARN_ON_ONCE(q
->quiesce_depth
<= 0)) {
302 } else if (!--q
->quiesce_depth
) {
303 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED
, q
);
306 spin_unlock_irqrestore(&q
->queue_lock
, flags
);
308 /* dispatch requests which are inserted during quiescing */
310 blk_mq_run_hw_queues(q
, true);
312 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue
);
314 void blk_mq_wake_waiters(struct request_queue
*q
)
316 struct blk_mq_hw_ctx
*hctx
;
319 queue_for_each_hw_ctx(q
, hctx
, i
)
320 if (blk_mq_hw_queue_mapped(hctx
))
321 blk_mq_tag_wakeup_all(hctx
->tags
, true);
324 void blk_rq_init(struct request_queue
*q
, struct request
*rq
)
326 memset(rq
, 0, sizeof(*rq
));
328 INIT_LIST_HEAD(&rq
->queuelist
);
330 rq
->__sector
= (sector_t
) -1;
331 INIT_HLIST_NODE(&rq
->hash
);
332 RB_CLEAR_NODE(&rq
->rb_node
);
333 rq
->tag
= BLK_MQ_NO_TAG
;
334 rq
->internal_tag
= BLK_MQ_NO_TAG
;
335 rq
->start_time_ns
= ktime_get_ns();
337 blk_crypto_rq_set_defaults(rq
);
339 EXPORT_SYMBOL(blk_rq_init
);
341 static struct request
*blk_mq_rq_ctx_init(struct blk_mq_alloc_data
*data
,
342 struct blk_mq_tags
*tags
, unsigned int tag
, u64 alloc_time_ns
)
344 struct blk_mq_ctx
*ctx
= data
->ctx
;
345 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
346 struct request_queue
*q
= data
->q
;
347 struct request
*rq
= tags
->static_rqs
[tag
];
352 rq
->cmd_flags
= data
->cmd_flags
;
354 if (data
->flags
& BLK_MQ_REQ_PM
)
355 data
->rq_flags
|= RQF_PM
;
356 if (blk_queue_io_stat(q
))
357 data
->rq_flags
|= RQF_IO_STAT
;
358 rq
->rq_flags
= data
->rq_flags
;
360 if (!(data
->rq_flags
& RQF_ELV
)) {
362 rq
->internal_tag
= BLK_MQ_NO_TAG
;
364 rq
->tag
= BLK_MQ_NO_TAG
;
365 rq
->internal_tag
= tag
;
369 if (blk_mq_need_time_stamp(rq
))
370 rq
->start_time_ns
= ktime_get_ns();
372 rq
->start_time_ns
= 0;
374 #ifdef CONFIG_BLK_RQ_ALLOC_TIME
375 rq
->alloc_time_ns
= alloc_time_ns
;
377 rq
->io_start_time_ns
= 0;
378 rq
->stats_sectors
= 0;
379 rq
->nr_phys_segments
= 0;
380 #if defined(CONFIG_BLK_DEV_INTEGRITY)
381 rq
->nr_integrity_segments
= 0;
384 rq
->end_io_data
= NULL
;
386 blk_crypto_rq_set_defaults(rq
);
387 INIT_LIST_HEAD(&rq
->queuelist
);
388 /* tag was already set */
389 WRITE_ONCE(rq
->deadline
, 0);
392 if (rq
->rq_flags
& RQF_ELV
) {
393 struct elevator_queue
*e
= data
->q
->elevator
;
395 INIT_HLIST_NODE(&rq
->hash
);
396 RB_CLEAR_NODE(&rq
->rb_node
);
398 if (!op_is_flush(data
->cmd_flags
) &&
399 e
->type
->ops
.prepare_request
) {
400 e
->type
->ops
.prepare_request(rq
);
401 rq
->rq_flags
|= RQF_ELVPRIV
;
408 static inline struct request
*
409 __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data
*data
,
412 unsigned int tag
, tag_offset
;
413 struct blk_mq_tags
*tags
;
415 unsigned long tag_mask
;
418 tag_mask
= blk_mq_get_tags(data
, data
->nr_tags
, &tag_offset
);
419 if (unlikely(!tag_mask
))
422 tags
= blk_mq_tags_from_data(data
);
423 for (i
= 0; tag_mask
; i
++) {
424 if (!(tag_mask
& (1UL << i
)))
426 tag
= tag_offset
+ i
;
427 prefetch(tags
->static_rqs
[tag
]);
428 tag_mask
&= ~(1UL << i
);
429 rq
= blk_mq_rq_ctx_init(data
, tags
, tag
, alloc_time_ns
);
430 rq_list_add(data
->cached_rq
, rq
);
433 /* caller already holds a reference, add for remainder */
434 percpu_ref_get_many(&data
->q
->q_usage_counter
, nr
- 1);
437 return rq_list_pop(data
->cached_rq
);
440 static struct request
*__blk_mq_alloc_requests(struct blk_mq_alloc_data
*data
)
442 struct request_queue
*q
= data
->q
;
443 u64 alloc_time_ns
= 0;
447 /* alloc_time includes depth and tag waits */
448 if (blk_queue_rq_alloc_time(q
))
449 alloc_time_ns
= ktime_get_ns();
451 if (data
->cmd_flags
& REQ_NOWAIT
)
452 data
->flags
|= BLK_MQ_REQ_NOWAIT
;
455 struct elevator_queue
*e
= q
->elevator
;
457 data
->rq_flags
|= RQF_ELV
;
460 * Flush/passthrough requests are special and go directly to the
461 * dispatch list. Don't include reserved tags in the
462 * limiting, as it isn't useful.
464 if (!op_is_flush(data
->cmd_flags
) &&
465 !blk_op_is_passthrough(data
->cmd_flags
) &&
466 e
->type
->ops
.limit_depth
&&
467 !(data
->flags
& BLK_MQ_REQ_RESERVED
))
468 e
->type
->ops
.limit_depth(data
->cmd_flags
, data
);
472 data
->ctx
= blk_mq_get_ctx(q
);
473 data
->hctx
= blk_mq_map_queue(q
, data
->cmd_flags
, data
->ctx
);
474 if (!(data
->rq_flags
& RQF_ELV
))
475 blk_mq_tag_busy(data
->hctx
);
478 * Try batched alloc if we want more than 1 tag.
480 if (data
->nr_tags
> 1) {
481 rq
= __blk_mq_alloc_requests_batch(data
, alloc_time_ns
);
488 * Waiting allocations only fail because of an inactive hctx. In that
489 * case just retry the hctx assignment and tag allocation as CPU hotplug
490 * should have migrated us to an online CPU by now.
492 tag
= blk_mq_get_tag(data
);
493 if (tag
== BLK_MQ_NO_TAG
) {
494 if (data
->flags
& BLK_MQ_REQ_NOWAIT
)
497 * Give up the CPU and sleep for a random short time to
498 * ensure that thread using a realtime scheduling class
499 * are migrated off the CPU, and thus off the hctx that
506 return blk_mq_rq_ctx_init(data
, blk_mq_tags_from_data(data
), tag
,
510 struct request
*blk_mq_alloc_request(struct request_queue
*q
, unsigned int op
,
511 blk_mq_req_flags_t flags
)
513 struct blk_mq_alloc_data data
= {
522 ret
= blk_queue_enter(q
, flags
);
526 rq
= __blk_mq_alloc_requests(&data
);
530 rq
->__sector
= (sector_t
) -1;
531 rq
->bio
= rq
->biotail
= NULL
;
535 return ERR_PTR(-EWOULDBLOCK
);
537 EXPORT_SYMBOL(blk_mq_alloc_request
);
539 struct request
*blk_mq_alloc_request_hctx(struct request_queue
*q
,
540 unsigned int op
, blk_mq_req_flags_t flags
, unsigned int hctx_idx
)
542 struct blk_mq_alloc_data data
= {
548 u64 alloc_time_ns
= 0;
553 /* alloc_time includes depth and tag waits */
554 if (blk_queue_rq_alloc_time(q
))
555 alloc_time_ns
= ktime_get_ns();
558 * If the tag allocator sleeps we could get an allocation for a
559 * different hardware context. No need to complicate the low level
560 * allocator for this for the rare use case of a command tied to
563 if (WARN_ON_ONCE(!(flags
& (BLK_MQ_REQ_NOWAIT
| BLK_MQ_REQ_RESERVED
))))
564 return ERR_PTR(-EINVAL
);
566 if (hctx_idx
>= q
->nr_hw_queues
)
567 return ERR_PTR(-EIO
);
569 ret
= blk_queue_enter(q
, flags
);
574 * Check if the hardware context is actually mapped to anything.
575 * If not tell the caller that it should skip this queue.
578 data
.hctx
= xa_load(&q
->hctx_table
, hctx_idx
);
579 if (!blk_mq_hw_queue_mapped(data
.hctx
))
581 cpu
= cpumask_first_and(data
.hctx
->cpumask
, cpu_online_mask
);
582 if (cpu
>= nr_cpu_ids
)
584 data
.ctx
= __blk_mq_get_ctx(q
, cpu
);
587 blk_mq_tag_busy(data
.hctx
);
589 data
.rq_flags
|= RQF_ELV
;
592 tag
= blk_mq_get_tag(&data
);
593 if (tag
== BLK_MQ_NO_TAG
)
595 return blk_mq_rq_ctx_init(&data
, blk_mq_tags_from_data(&data
), tag
,
602 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx
);
604 static void __blk_mq_free_request(struct request
*rq
)
606 struct request_queue
*q
= rq
->q
;
607 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
608 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
609 const int sched_tag
= rq
->internal_tag
;
611 blk_crypto_free_request(rq
);
612 blk_pm_mark_last_busy(rq
);
614 if (rq
->tag
!= BLK_MQ_NO_TAG
)
615 blk_mq_put_tag(hctx
->tags
, ctx
, rq
->tag
);
616 if (sched_tag
!= BLK_MQ_NO_TAG
)
617 blk_mq_put_tag(hctx
->sched_tags
, ctx
, sched_tag
);
618 blk_mq_sched_restart(hctx
);
622 void blk_mq_free_request(struct request
*rq
)
624 struct request_queue
*q
= rq
->q
;
625 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
627 if ((rq
->rq_flags
& RQF_ELVPRIV
) &&
628 q
->elevator
->type
->ops
.finish_request
)
629 q
->elevator
->type
->ops
.finish_request(rq
);
631 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
)
632 __blk_mq_dec_active_requests(hctx
);
634 if (unlikely(laptop_mode
&& !blk_rq_is_passthrough(rq
)))
635 laptop_io_completion(q
->disk
->bdi
);
639 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
640 if (req_ref_put_and_test(rq
))
641 __blk_mq_free_request(rq
);
643 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
645 void blk_mq_free_plug_rqs(struct blk_plug
*plug
)
649 while ((rq
= rq_list_pop(&plug
->cached_rq
)) != NULL
)
650 blk_mq_free_request(rq
);
653 void blk_dump_rq_flags(struct request
*rq
, char *msg
)
655 printk(KERN_INFO
"%s: dev %s: flags=%llx\n", msg
,
656 rq
->q
->disk
? rq
->q
->disk
->disk_name
: "?",
657 (unsigned long long) rq
->cmd_flags
);
659 printk(KERN_INFO
" sector %llu, nr/cnr %u/%u\n",
660 (unsigned long long)blk_rq_pos(rq
),
661 blk_rq_sectors(rq
), blk_rq_cur_sectors(rq
));
662 printk(KERN_INFO
" bio %p, biotail %p, len %u\n",
663 rq
->bio
, rq
->biotail
, blk_rq_bytes(rq
));
665 EXPORT_SYMBOL(blk_dump_rq_flags
);
667 static void req_bio_endio(struct request
*rq
, struct bio
*bio
,
668 unsigned int nbytes
, blk_status_t error
)
670 if (unlikely(error
)) {
671 bio
->bi_status
= error
;
672 } else if (req_op(rq
) == REQ_OP_ZONE_APPEND
) {
674 * Partial zone append completions cannot be supported as the
675 * BIO fragments may end up not being written sequentially.
677 if (bio
->bi_iter
.bi_size
!= nbytes
)
678 bio
->bi_status
= BLK_STS_IOERR
;
680 bio
->bi_iter
.bi_sector
= rq
->__sector
;
683 bio_advance(bio
, nbytes
);
685 if (unlikely(rq
->rq_flags
& RQF_QUIET
))
686 bio_set_flag(bio
, BIO_QUIET
);
687 /* don't actually finish bio if it's part of flush sequence */
688 if (bio
->bi_iter
.bi_size
== 0 && !(rq
->rq_flags
& RQF_FLUSH_SEQ
))
692 static void blk_account_io_completion(struct request
*req
, unsigned int bytes
)
694 if (req
->part
&& blk_do_io_stat(req
)) {
695 const int sgrp
= op_stat_group(req_op(req
));
698 part_stat_add(req
->part
, sectors
[sgrp
], bytes
>> 9);
703 static void blk_print_req_error(struct request
*req
, blk_status_t status
)
705 printk_ratelimited(KERN_ERR
706 "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
707 "phys_seg %u prio class %u\n",
708 blk_status_to_str(status
),
709 req
->q
->disk
? req
->q
->disk
->disk_name
: "?",
710 blk_rq_pos(req
), req_op(req
), blk_op_str(req_op(req
)),
711 req
->cmd_flags
& ~REQ_OP_MASK
,
712 req
->nr_phys_segments
,
713 IOPRIO_PRIO_CLASS(req
->ioprio
));
717 * Fully end IO on a request. Does not support partial completions, or
720 static void blk_complete_request(struct request
*req
)
722 const bool is_flush
= (req
->rq_flags
& RQF_FLUSH_SEQ
) != 0;
723 int total_bytes
= blk_rq_bytes(req
);
724 struct bio
*bio
= req
->bio
;
726 trace_block_rq_complete(req
, BLK_STS_OK
, total_bytes
);
731 #ifdef CONFIG_BLK_DEV_INTEGRITY
732 if (blk_integrity_rq(req
) && req_op(req
) == REQ_OP_READ
)
733 req
->q
->integrity
.profile
->complete_fn(req
, total_bytes
);
736 blk_account_io_completion(req
, total_bytes
);
739 struct bio
*next
= bio
->bi_next
;
741 /* Completion has already been traced */
742 bio_clear_flag(bio
, BIO_TRACE_COMPLETION
);
744 if (req_op(req
) == REQ_OP_ZONE_APPEND
)
745 bio
->bi_iter
.bi_sector
= req
->__sector
;
753 * Reset counters so that the request stacking driver
754 * can find how many bytes remain in the request
762 * blk_update_request - Complete multiple bytes without completing the request
763 * @req: the request being processed
764 * @error: block status code
765 * @nr_bytes: number of bytes to complete for @req
768 * Ends I/O on a number of bytes attached to @req, but doesn't complete
769 * the request structure even if @req doesn't have leftover.
770 * If @req has leftover, sets it up for the next range of segments.
772 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
773 * %false return from this function.
776 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
777 * except in the consistency check at the end of this function.
780 * %false - this request doesn't have any more data
781 * %true - this request has more data
783 bool blk_update_request(struct request
*req
, blk_status_t error
,
784 unsigned int nr_bytes
)
788 trace_block_rq_complete(req
, error
, nr_bytes
);
793 #ifdef CONFIG_BLK_DEV_INTEGRITY
794 if (blk_integrity_rq(req
) && req_op(req
) == REQ_OP_READ
&&
796 req
->q
->integrity
.profile
->complete_fn(req
, nr_bytes
);
799 if (unlikely(error
&& !blk_rq_is_passthrough(req
) &&
800 !(req
->rq_flags
& RQF_QUIET
)) &&
801 !test_bit(GD_DEAD
, &req
->q
->disk
->state
)) {
802 blk_print_req_error(req
, error
);
803 trace_block_rq_error(req
, error
, nr_bytes
);
806 blk_account_io_completion(req
, nr_bytes
);
810 struct bio
*bio
= req
->bio
;
811 unsigned bio_bytes
= min(bio
->bi_iter
.bi_size
, nr_bytes
);
813 if (bio_bytes
== bio
->bi_iter
.bi_size
)
814 req
->bio
= bio
->bi_next
;
816 /* Completion has already been traced */
817 bio_clear_flag(bio
, BIO_TRACE_COMPLETION
);
818 req_bio_endio(req
, bio
, bio_bytes
, error
);
820 total_bytes
+= bio_bytes
;
821 nr_bytes
-= bio_bytes
;
832 * Reset counters so that the request stacking driver
833 * can find how many bytes remain in the request
840 req
->__data_len
-= total_bytes
;
842 /* update sector only for requests with clear definition of sector */
843 if (!blk_rq_is_passthrough(req
))
844 req
->__sector
+= total_bytes
>> 9;
846 /* mixed attributes always follow the first bio */
847 if (req
->rq_flags
& RQF_MIXED_MERGE
) {
848 req
->cmd_flags
&= ~REQ_FAILFAST_MASK
;
849 req
->cmd_flags
|= req
->bio
->bi_opf
& REQ_FAILFAST_MASK
;
852 if (!(req
->rq_flags
& RQF_SPECIAL_PAYLOAD
)) {
854 * If total number of sectors is less than the first segment
855 * size, something has gone terribly wrong.
857 if (blk_rq_bytes(req
) < blk_rq_cur_bytes(req
)) {
858 blk_dump_rq_flags(req
, "request botched");
859 req
->__data_len
= blk_rq_cur_bytes(req
);
862 /* recalculate the number of segments */
863 req
->nr_phys_segments
= blk_recalc_rq_segments(req
);
868 EXPORT_SYMBOL_GPL(blk_update_request
);
870 static void __blk_account_io_done(struct request
*req
, u64 now
)
872 const int sgrp
= op_stat_group(req_op(req
));
875 update_io_ticks(req
->part
, jiffies
, true);
876 part_stat_inc(req
->part
, ios
[sgrp
]);
877 part_stat_add(req
->part
, nsecs
[sgrp
], now
- req
->start_time_ns
);
881 static inline void blk_account_io_done(struct request
*req
, u64 now
)
884 * Account IO completion. flush_rq isn't accounted as a
885 * normal IO on queueing nor completion. Accounting the
886 * containing request is enough.
888 if (blk_do_io_stat(req
) && req
->part
&&
889 !(req
->rq_flags
& RQF_FLUSH_SEQ
))
890 __blk_account_io_done(req
, now
);
893 static void __blk_account_io_start(struct request
*rq
)
896 * All non-passthrough requests are created from a bio with one
897 * exception: when a flush command that is part of a flush sequence
898 * generated by the state machine in blk-flush.c is cloned onto the
899 * lower device by dm-multipath we can get here without a bio.
902 rq
->part
= rq
->bio
->bi_bdev
;
904 rq
->part
= rq
->q
->disk
->part0
;
907 update_io_ticks(rq
->part
, jiffies
, false);
911 static inline void blk_account_io_start(struct request
*req
)
913 if (blk_do_io_stat(req
))
914 __blk_account_io_start(req
);
917 static inline void __blk_mq_end_request_acct(struct request
*rq
, u64 now
)
919 if (rq
->rq_flags
& RQF_STATS
) {
920 blk_mq_poll_stats_start(rq
->q
);
921 blk_stat_add(rq
, now
);
924 blk_mq_sched_completed_request(rq
, now
);
925 blk_account_io_done(rq
, now
);
928 inline void __blk_mq_end_request(struct request
*rq
, blk_status_t error
)
930 if (blk_mq_need_time_stamp(rq
))
931 __blk_mq_end_request_acct(rq
, ktime_get_ns());
934 rq_qos_done(rq
->q
, rq
);
935 rq
->end_io(rq
, error
);
937 blk_mq_free_request(rq
);
940 EXPORT_SYMBOL(__blk_mq_end_request
);
942 void blk_mq_end_request(struct request
*rq
, blk_status_t error
)
944 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
946 __blk_mq_end_request(rq
, error
);
948 EXPORT_SYMBOL(blk_mq_end_request
);
950 #define TAG_COMP_BATCH 32
952 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx
*hctx
,
953 int *tag_array
, int nr_tags
)
955 struct request_queue
*q
= hctx
->queue
;
958 * All requests should have been marked as RQF_MQ_INFLIGHT, so
959 * update hctx->nr_active in batch
961 if (hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)
962 __blk_mq_sub_active_requests(hctx
, nr_tags
);
964 blk_mq_put_tags(hctx
->tags
, tag_array
, nr_tags
);
965 percpu_ref_put_many(&q
->q_usage_counter
, nr_tags
);
968 void blk_mq_end_request_batch(struct io_comp_batch
*iob
)
970 int tags
[TAG_COMP_BATCH
], nr_tags
= 0;
971 struct blk_mq_hw_ctx
*cur_hctx
= NULL
;
976 now
= ktime_get_ns();
978 while ((rq
= rq_list_pop(&iob
->req_list
)) != NULL
) {
980 prefetch(rq
->rq_next
);
982 blk_complete_request(rq
);
984 __blk_mq_end_request_acct(rq
, now
);
986 rq_qos_done(rq
->q
, rq
);
988 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
989 if (!req_ref_put_and_test(rq
))
992 blk_crypto_free_request(rq
);
993 blk_pm_mark_last_busy(rq
);
995 if (nr_tags
== TAG_COMP_BATCH
|| cur_hctx
!= rq
->mq_hctx
) {
997 blk_mq_flush_tag_batch(cur_hctx
, tags
, nr_tags
);
999 cur_hctx
= rq
->mq_hctx
;
1001 tags
[nr_tags
++] = rq
->tag
;
1005 blk_mq_flush_tag_batch(cur_hctx
, tags
, nr_tags
);
1007 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch
);
1009 static void blk_complete_reqs(struct llist_head
*list
)
1011 struct llist_node
*entry
= llist_reverse_order(llist_del_all(list
));
1012 struct request
*rq
, *next
;
1014 llist_for_each_entry_safe(rq
, next
, entry
, ipi_list
)
1015 rq
->q
->mq_ops
->complete(rq
);
1018 static __latent_entropy
void blk_done_softirq(struct softirq_action
*h
)
1020 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done
));
1023 static int blk_softirq_cpu_dead(unsigned int cpu
)
1025 blk_complete_reqs(&per_cpu(blk_cpu_done
, cpu
));
1029 static void __blk_mq_complete_request_remote(void *data
)
1031 __raise_softirq_irqoff(BLOCK_SOFTIRQ
);
1034 static inline bool blk_mq_complete_need_ipi(struct request
*rq
)
1036 int cpu
= raw_smp_processor_id();
1038 if (!IS_ENABLED(CONFIG_SMP
) ||
1039 !test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
))
1042 * With force threaded interrupts enabled, raising softirq from an SMP
1043 * function call will always result in waking the ksoftirqd thread.
1044 * This is probably worse than completing the request on a different
1047 if (force_irqthreads())
1050 /* same CPU or cache domain? Complete locally */
1051 if (cpu
== rq
->mq_ctx
->cpu
||
1052 (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
) &&
1053 cpus_share_cache(cpu
, rq
->mq_ctx
->cpu
)))
1056 /* don't try to IPI to an offline CPU */
1057 return cpu_online(rq
->mq_ctx
->cpu
);
1060 static void blk_mq_complete_send_ipi(struct request
*rq
)
1062 struct llist_head
*list
;
1065 cpu
= rq
->mq_ctx
->cpu
;
1066 list
= &per_cpu(blk_cpu_done
, cpu
);
1067 if (llist_add(&rq
->ipi_list
, list
)) {
1068 INIT_CSD(&rq
->csd
, __blk_mq_complete_request_remote
, rq
);
1069 smp_call_function_single_async(cpu
, &rq
->csd
);
1073 static void blk_mq_raise_softirq(struct request
*rq
)
1075 struct llist_head
*list
;
1078 list
= this_cpu_ptr(&blk_cpu_done
);
1079 if (llist_add(&rq
->ipi_list
, list
))
1080 raise_softirq(BLOCK_SOFTIRQ
);
1084 bool blk_mq_complete_request_remote(struct request
*rq
)
1086 WRITE_ONCE(rq
->state
, MQ_RQ_COMPLETE
);
1089 * For a polled request, always complete locally, it's pointless
1090 * to redirect the completion.
1092 if (rq
->cmd_flags
& REQ_POLLED
)
1095 if (blk_mq_complete_need_ipi(rq
)) {
1096 blk_mq_complete_send_ipi(rq
);
1100 if (rq
->q
->nr_hw_queues
== 1) {
1101 blk_mq_raise_softirq(rq
);
1106 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote
);
1109 * blk_mq_complete_request - end I/O on a request
1110 * @rq: the request being processed
1113 * Complete a request by scheduling the ->complete_rq operation.
1115 void blk_mq_complete_request(struct request
*rq
)
1117 if (!blk_mq_complete_request_remote(rq
))
1118 rq
->q
->mq_ops
->complete(rq
);
1120 EXPORT_SYMBOL(blk_mq_complete_request
);
1123 * blk_mq_start_request - Start processing a request
1124 * @rq: Pointer to request to be started
1126 * Function used by device drivers to notify the block layer that a request
1127 * is going to be processed now, so blk layer can do proper initializations
1128 * such as starting the timeout timer.
1130 void blk_mq_start_request(struct request
*rq
)
1132 struct request_queue
*q
= rq
->q
;
1134 trace_block_rq_issue(rq
);
1136 if (test_bit(QUEUE_FLAG_STATS
, &q
->queue_flags
)) {
1137 rq
->io_start_time_ns
= ktime_get_ns();
1138 rq
->stats_sectors
= blk_rq_sectors(rq
);
1139 rq
->rq_flags
|= RQF_STATS
;
1140 rq_qos_issue(q
, rq
);
1143 WARN_ON_ONCE(blk_mq_rq_state(rq
) != MQ_RQ_IDLE
);
1146 WRITE_ONCE(rq
->state
, MQ_RQ_IN_FLIGHT
);
1148 #ifdef CONFIG_BLK_DEV_INTEGRITY
1149 if (blk_integrity_rq(rq
) && req_op(rq
) == REQ_OP_WRITE
)
1150 q
->integrity
.profile
->prepare_fn(rq
);
1152 if (rq
->bio
&& rq
->bio
->bi_opf
& REQ_POLLED
)
1153 WRITE_ONCE(rq
->bio
->bi_cookie
, blk_rq_to_qc(rq
));
1155 EXPORT_SYMBOL(blk_mq_start_request
);
1158 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
1159 * queues. This is important for md arrays to benefit from merging
1162 static inline unsigned short blk_plug_max_rq_count(struct blk_plug
*plug
)
1164 if (plug
->multiple_queues
)
1165 return BLK_MAX_REQUEST_COUNT
* 2;
1166 return BLK_MAX_REQUEST_COUNT
;
1169 static void blk_add_rq_to_plug(struct blk_plug
*plug
, struct request
*rq
)
1171 struct request
*last
= rq_list_peek(&plug
->mq_list
);
1173 if (!plug
->rq_count
) {
1174 trace_block_plug(rq
->q
);
1175 } else if (plug
->rq_count
>= blk_plug_max_rq_count(plug
) ||
1176 (!blk_queue_nomerges(rq
->q
) &&
1177 blk_rq_bytes(last
) >= BLK_PLUG_FLUSH_SIZE
)) {
1178 blk_mq_flush_plug_list(plug
, false);
1179 trace_block_plug(rq
->q
);
1182 if (!plug
->multiple_queues
&& last
&& last
->q
!= rq
->q
)
1183 plug
->multiple_queues
= true;
1184 if (!plug
->has_elevator
&& (rq
->rq_flags
& RQF_ELV
))
1185 plug
->has_elevator
= true;
1187 rq_list_add(&plug
->mq_list
, rq
);
1192 * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
1193 * @rq: request to insert
1194 * @at_head: insert request at head or tail of queue
1197 * Insert a fully prepared request at the back of the I/O scheduler queue
1198 * for execution. Don't wait for completion.
1201 * This function will invoke @done directly if the queue is dead.
1203 void blk_execute_rq_nowait(struct request
*rq
, bool at_head
)
1205 WARN_ON(irqs_disabled());
1206 WARN_ON(!blk_rq_is_passthrough(rq
));
1208 blk_account_io_start(rq
);
1210 blk_add_rq_to_plug(current
->plug
, rq
);
1212 blk_mq_sched_insert_request(rq
, at_head
, true, false);
1214 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait
);
1216 struct blk_rq_wait
{
1217 struct completion done
;
1221 static void blk_end_sync_rq(struct request
*rq
, blk_status_t ret
)
1223 struct blk_rq_wait
*wait
= rq
->end_io_data
;
1226 complete(&wait
->done
);
1229 static bool blk_rq_is_poll(struct request
*rq
)
1233 if (rq
->mq_hctx
->type
!= HCTX_TYPE_POLL
)
1235 if (WARN_ON_ONCE(!rq
->bio
))
1240 static void blk_rq_poll_completion(struct request
*rq
, struct completion
*wait
)
1243 bio_poll(rq
->bio
, NULL
, 0);
1245 } while (!completion_done(wait
));
1249 * blk_execute_rq - insert a request into queue for execution
1250 * @rq: request to insert
1251 * @at_head: insert request at head or tail of queue
1254 * Insert a fully prepared request at the back of the I/O scheduler queue
1255 * for execution and wait for completion.
1256 * Return: The blk_status_t result provided to blk_mq_end_request().
1258 blk_status_t
blk_execute_rq(struct request
*rq
, bool at_head
)
1260 struct blk_rq_wait wait
= {
1261 .done
= COMPLETION_INITIALIZER_ONSTACK(wait
.done
),
1264 WARN_ON(irqs_disabled());
1265 WARN_ON(!blk_rq_is_passthrough(rq
));
1267 rq
->end_io_data
= &wait
;
1268 rq
->end_io
= blk_end_sync_rq
;
1270 blk_account_io_start(rq
);
1271 blk_mq_sched_insert_request(rq
, at_head
, true, false);
1273 if (blk_rq_is_poll(rq
)) {
1274 blk_rq_poll_completion(rq
, &wait
.done
);
1277 * Prevent hang_check timer from firing at us during very long
1280 unsigned long hang_check
= sysctl_hung_task_timeout_secs
;
1283 while (!wait_for_completion_io_timeout(&wait
.done
,
1284 hang_check
* (HZ
/2)))
1287 wait_for_completion_io(&wait
.done
);
1292 EXPORT_SYMBOL(blk_execute_rq
);
1294 static void __blk_mq_requeue_request(struct request
*rq
)
1296 struct request_queue
*q
= rq
->q
;
1298 blk_mq_put_driver_tag(rq
);
1300 trace_block_rq_requeue(rq
);
1301 rq_qos_requeue(q
, rq
);
1303 if (blk_mq_request_started(rq
)) {
1304 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
1305 rq
->rq_flags
&= ~RQF_TIMED_OUT
;
1309 void blk_mq_requeue_request(struct request
*rq
, bool kick_requeue_list
)
1311 __blk_mq_requeue_request(rq
);
1313 /* this request will be re-inserted to io scheduler queue */
1314 blk_mq_sched_requeue_request(rq
);
1316 blk_mq_add_to_requeue_list(rq
, true, kick_requeue_list
);
1318 EXPORT_SYMBOL(blk_mq_requeue_request
);
1320 static void blk_mq_requeue_work(struct work_struct
*work
)
1322 struct request_queue
*q
=
1323 container_of(work
, struct request_queue
, requeue_work
.work
);
1325 struct request
*rq
, *next
;
1327 spin_lock_irq(&q
->requeue_lock
);
1328 list_splice_init(&q
->requeue_list
, &rq_list
);
1329 spin_unlock_irq(&q
->requeue_lock
);
1331 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
1332 if (!(rq
->rq_flags
& (RQF_SOFTBARRIER
| RQF_DONTPREP
)))
1335 rq
->rq_flags
&= ~RQF_SOFTBARRIER
;
1336 list_del_init(&rq
->queuelist
);
1338 * If RQF_DONTPREP, rq has contained some driver specific
1339 * data, so insert it to hctx dispatch list to avoid any
1342 if (rq
->rq_flags
& RQF_DONTPREP
)
1343 blk_mq_request_bypass_insert(rq
, false, false);
1345 blk_mq_sched_insert_request(rq
, true, false, false);
1348 while (!list_empty(&rq_list
)) {
1349 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
1350 list_del_init(&rq
->queuelist
);
1351 blk_mq_sched_insert_request(rq
, false, false, false);
1354 blk_mq_run_hw_queues(q
, false);
1357 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
,
1358 bool kick_requeue_list
)
1360 struct request_queue
*q
= rq
->q
;
1361 unsigned long flags
;
1364 * We abuse this flag that is otherwise used by the I/O scheduler to
1365 * request head insertion from the workqueue.
1367 BUG_ON(rq
->rq_flags
& RQF_SOFTBARRIER
);
1369 spin_lock_irqsave(&q
->requeue_lock
, flags
);
1371 rq
->rq_flags
|= RQF_SOFTBARRIER
;
1372 list_add(&rq
->queuelist
, &q
->requeue_list
);
1374 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
1376 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
1378 if (kick_requeue_list
)
1379 blk_mq_kick_requeue_list(q
);
1382 void blk_mq_kick_requeue_list(struct request_queue
*q
)
1384 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
, 0);
1386 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
1388 void blk_mq_delay_kick_requeue_list(struct request_queue
*q
,
1389 unsigned long msecs
)
1391 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
,
1392 msecs_to_jiffies(msecs
));
1394 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list
);
1396 static bool blk_mq_rq_inflight(struct request
*rq
, void *priv
,
1400 * If we find a request that isn't idle we know the queue is busy
1401 * as it's checked in the iter.
1402 * Return false to stop the iteration.
1404 if (blk_mq_request_started(rq
)) {
1414 bool blk_mq_queue_inflight(struct request_queue
*q
)
1418 blk_mq_queue_tag_busy_iter(q
, blk_mq_rq_inflight
, &busy
);
1421 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight
);
1423 static void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
1425 req
->rq_flags
|= RQF_TIMED_OUT
;
1426 if (req
->q
->mq_ops
->timeout
) {
1427 enum blk_eh_timer_return ret
;
1429 ret
= req
->q
->mq_ops
->timeout(req
, reserved
);
1430 if (ret
== BLK_EH_DONE
)
1432 WARN_ON_ONCE(ret
!= BLK_EH_RESET_TIMER
);
1438 static bool blk_mq_req_expired(struct request
*rq
, unsigned long *next
)
1440 unsigned long deadline
;
1442 if (blk_mq_rq_state(rq
) != MQ_RQ_IN_FLIGHT
)
1444 if (rq
->rq_flags
& RQF_TIMED_OUT
)
1447 deadline
= READ_ONCE(rq
->deadline
);
1448 if (time_after_eq(jiffies
, deadline
))
1453 else if (time_after(*next
, deadline
))
1458 void blk_mq_put_rq_ref(struct request
*rq
)
1460 if (is_flush_rq(rq
))
1462 else if (req_ref_put_and_test(rq
))
1463 __blk_mq_free_request(rq
);
1466 static bool blk_mq_check_expired(struct request
*rq
, void *priv
, bool reserved
)
1468 unsigned long *next
= priv
;
1471 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1472 * be reallocated underneath the timeout handler's processing, then
1473 * the expire check is reliable. If the request is not expired, then
1474 * it was completed and reallocated as a new request after returning
1475 * from blk_mq_check_expired().
1477 if (blk_mq_req_expired(rq
, next
))
1478 blk_mq_rq_timed_out(rq
, reserved
);
1482 static void blk_mq_timeout_work(struct work_struct
*work
)
1484 struct request_queue
*q
=
1485 container_of(work
, struct request_queue
, timeout_work
);
1486 unsigned long next
= 0;
1487 struct blk_mq_hw_ctx
*hctx
;
1490 /* A deadlock might occur if a request is stuck requiring a
1491 * timeout at the same time a queue freeze is waiting
1492 * completion, since the timeout code would not be able to
1493 * acquire the queue reference here.
1495 * That's why we don't use blk_queue_enter here; instead, we use
1496 * percpu_ref_tryget directly, because we need to be able to
1497 * obtain a reference even in the short window between the queue
1498 * starting to freeze, by dropping the first reference in
1499 * blk_freeze_queue_start, and the moment the last request is
1500 * consumed, marked by the instant q_usage_counter reaches
1503 if (!percpu_ref_tryget(&q
->q_usage_counter
))
1506 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_expired
, &next
);
1509 mod_timer(&q
->timeout
, next
);
1512 * Request timeouts are handled as a forward rolling timer. If
1513 * we end up here it means that no requests are pending and
1514 * also that no request has been pending for a while. Mark
1515 * each hctx as idle.
1517 queue_for_each_hw_ctx(q
, hctx
, i
) {
1518 /* the hctx may be unmapped, so check it here */
1519 if (blk_mq_hw_queue_mapped(hctx
))
1520 blk_mq_tag_idle(hctx
);
1526 struct flush_busy_ctx_data
{
1527 struct blk_mq_hw_ctx
*hctx
;
1528 struct list_head
*list
;
1531 static bool flush_busy_ctx(struct sbitmap
*sb
, unsigned int bitnr
, void *data
)
1533 struct flush_busy_ctx_data
*flush_data
= data
;
1534 struct blk_mq_hw_ctx
*hctx
= flush_data
->hctx
;
1535 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
1536 enum hctx_type type
= hctx
->type
;
1538 spin_lock(&ctx
->lock
);
1539 list_splice_tail_init(&ctx
->rq_lists
[type
], flush_data
->list
);
1540 sbitmap_clear_bit(sb
, bitnr
);
1541 spin_unlock(&ctx
->lock
);
1546 * Process software queues that have been marked busy, splicing them
1547 * to the for-dispatch
1549 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
1551 struct flush_busy_ctx_data data
= {
1556 sbitmap_for_each_set(&hctx
->ctx_map
, flush_busy_ctx
, &data
);
1558 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs
);
1560 struct dispatch_rq_data
{
1561 struct blk_mq_hw_ctx
*hctx
;
1565 static bool dispatch_rq_from_ctx(struct sbitmap
*sb
, unsigned int bitnr
,
1568 struct dispatch_rq_data
*dispatch_data
= data
;
1569 struct blk_mq_hw_ctx
*hctx
= dispatch_data
->hctx
;
1570 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
1571 enum hctx_type type
= hctx
->type
;
1573 spin_lock(&ctx
->lock
);
1574 if (!list_empty(&ctx
->rq_lists
[type
])) {
1575 dispatch_data
->rq
= list_entry_rq(ctx
->rq_lists
[type
].next
);
1576 list_del_init(&dispatch_data
->rq
->queuelist
);
1577 if (list_empty(&ctx
->rq_lists
[type
]))
1578 sbitmap_clear_bit(sb
, bitnr
);
1580 spin_unlock(&ctx
->lock
);
1582 return !dispatch_data
->rq
;
1585 struct request
*blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx
*hctx
,
1586 struct blk_mq_ctx
*start
)
1588 unsigned off
= start
? start
->index_hw
[hctx
->type
] : 0;
1589 struct dispatch_rq_data data
= {
1594 __sbitmap_for_each_set(&hctx
->ctx_map
, off
,
1595 dispatch_rq_from_ctx
, &data
);
1600 static bool __blk_mq_alloc_driver_tag(struct request
*rq
)
1602 struct sbitmap_queue
*bt
= &rq
->mq_hctx
->tags
->bitmap_tags
;
1603 unsigned int tag_offset
= rq
->mq_hctx
->tags
->nr_reserved_tags
;
1606 blk_mq_tag_busy(rq
->mq_hctx
);
1608 if (blk_mq_tag_is_reserved(rq
->mq_hctx
->sched_tags
, rq
->internal_tag
)) {
1609 bt
= &rq
->mq_hctx
->tags
->breserved_tags
;
1612 if (!hctx_may_queue(rq
->mq_hctx
, bt
))
1616 tag
= __sbitmap_queue_get(bt
);
1617 if (tag
== BLK_MQ_NO_TAG
)
1620 rq
->tag
= tag
+ tag_offset
;
1624 bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
1626 if (rq
->tag
== BLK_MQ_NO_TAG
&& !__blk_mq_alloc_driver_tag(rq
))
1629 if ((hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
) &&
1630 !(rq
->rq_flags
& RQF_MQ_INFLIGHT
)) {
1631 rq
->rq_flags
|= RQF_MQ_INFLIGHT
;
1632 __blk_mq_inc_active_requests(hctx
);
1634 hctx
->tags
->rqs
[rq
->tag
] = rq
;
1638 static int blk_mq_dispatch_wake(wait_queue_entry_t
*wait
, unsigned mode
,
1639 int flags
, void *key
)
1641 struct blk_mq_hw_ctx
*hctx
;
1643 hctx
= container_of(wait
, struct blk_mq_hw_ctx
, dispatch_wait
);
1645 spin_lock(&hctx
->dispatch_wait_lock
);
1646 if (!list_empty(&wait
->entry
)) {
1647 struct sbitmap_queue
*sbq
;
1649 list_del_init(&wait
->entry
);
1650 sbq
= &hctx
->tags
->bitmap_tags
;
1651 atomic_dec(&sbq
->ws_active
);
1653 spin_unlock(&hctx
->dispatch_wait_lock
);
1655 blk_mq_run_hw_queue(hctx
, true);
1660 * Mark us waiting for a tag. For shared tags, this involves hooking us into
1661 * the tag wakeups. For non-shared tags, we can simply mark us needing a
1662 * restart. For both cases, take care to check the condition again after
1663 * marking us as waiting.
1665 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx
*hctx
,
1668 struct sbitmap_queue
*sbq
= &hctx
->tags
->bitmap_tags
;
1669 struct wait_queue_head
*wq
;
1670 wait_queue_entry_t
*wait
;
1673 if (!(hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)) {
1674 blk_mq_sched_mark_restart_hctx(hctx
);
1677 * It's possible that a tag was freed in the window between the
1678 * allocation failure and adding the hardware queue to the wait
1681 * Don't clear RESTART here, someone else could have set it.
1682 * At most this will cost an extra queue run.
1684 return blk_mq_get_driver_tag(rq
);
1687 wait
= &hctx
->dispatch_wait
;
1688 if (!list_empty_careful(&wait
->entry
))
1691 wq
= &bt_wait_ptr(sbq
, hctx
)->wait
;
1693 spin_lock_irq(&wq
->lock
);
1694 spin_lock(&hctx
->dispatch_wait_lock
);
1695 if (!list_empty(&wait
->entry
)) {
1696 spin_unlock(&hctx
->dispatch_wait_lock
);
1697 spin_unlock_irq(&wq
->lock
);
1701 atomic_inc(&sbq
->ws_active
);
1702 wait
->flags
&= ~WQ_FLAG_EXCLUSIVE
;
1703 __add_wait_queue(wq
, wait
);
1706 * It's possible that a tag was freed in the window between the
1707 * allocation failure and adding the hardware queue to the wait
1710 ret
= blk_mq_get_driver_tag(rq
);
1712 spin_unlock(&hctx
->dispatch_wait_lock
);
1713 spin_unlock_irq(&wq
->lock
);
1718 * We got a tag, remove ourselves from the wait queue to ensure
1719 * someone else gets the wakeup.
1721 list_del_init(&wait
->entry
);
1722 atomic_dec(&sbq
->ws_active
);
1723 spin_unlock(&hctx
->dispatch_wait_lock
);
1724 spin_unlock_irq(&wq
->lock
);
1729 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1730 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1732 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1733 * - EWMA is one simple way to compute running average value
1734 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1735 * - take 4 as factor for avoiding to get too small(0) result, and this
1736 * factor doesn't matter because EWMA decreases exponentially
1738 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx
*hctx
, bool busy
)
1742 ewma
= hctx
->dispatch_busy
;
1747 ewma
*= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
- 1;
1749 ewma
+= 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR
;
1750 ewma
/= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT
;
1752 hctx
->dispatch_busy
= ewma
;
1755 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1757 static void blk_mq_handle_dev_resource(struct request
*rq
,
1758 struct list_head
*list
)
1760 struct request
*next
=
1761 list_first_entry_or_null(list
, struct request
, queuelist
);
1764 * If an I/O scheduler has been configured and we got a driver tag for
1765 * the next request already, free it.
1768 blk_mq_put_driver_tag(next
);
1770 list_add(&rq
->queuelist
, list
);
1771 __blk_mq_requeue_request(rq
);
1774 static void blk_mq_handle_zone_resource(struct request
*rq
,
1775 struct list_head
*zone_list
)
1778 * If we end up here it is because we cannot dispatch a request to a
1779 * specific zone due to LLD level zone-write locking or other zone
1780 * related resource not being available. In this case, set the request
1781 * aside in zone_list for retrying it later.
1783 list_add(&rq
->queuelist
, zone_list
);
1784 __blk_mq_requeue_request(rq
);
1787 enum prep_dispatch
{
1789 PREP_DISPATCH_NO_TAG
,
1790 PREP_DISPATCH_NO_BUDGET
,
1793 static enum prep_dispatch
blk_mq_prep_dispatch_rq(struct request
*rq
,
1796 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
1797 int budget_token
= -1;
1800 budget_token
= blk_mq_get_dispatch_budget(rq
->q
);
1801 if (budget_token
< 0) {
1802 blk_mq_put_driver_tag(rq
);
1803 return PREP_DISPATCH_NO_BUDGET
;
1805 blk_mq_set_rq_budget_token(rq
, budget_token
);
1808 if (!blk_mq_get_driver_tag(rq
)) {
1810 * The initial allocation attempt failed, so we need to
1811 * rerun the hardware queue when a tag is freed. The
1812 * waitqueue takes care of that. If the queue is run
1813 * before we add this entry back on the dispatch list,
1814 * we'll re-run it below.
1816 if (!blk_mq_mark_tag_wait(hctx
, rq
)) {
1818 * All budgets not got from this function will be put
1819 * together during handling partial dispatch
1822 blk_mq_put_dispatch_budget(rq
->q
, budget_token
);
1823 return PREP_DISPATCH_NO_TAG
;
1827 return PREP_DISPATCH_OK
;
1830 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1831 static void blk_mq_release_budgets(struct request_queue
*q
,
1832 struct list_head
*list
)
1836 list_for_each_entry(rq
, list
, queuelist
) {
1837 int budget_token
= blk_mq_get_rq_budget_token(rq
);
1839 if (budget_token
>= 0)
1840 blk_mq_put_dispatch_budget(q
, budget_token
);
1845 * Returns true if we did some work AND can potentially do more.
1847 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
,
1848 unsigned int nr_budgets
)
1850 enum prep_dispatch prep
;
1851 struct request_queue
*q
= hctx
->queue
;
1852 struct request
*rq
, *nxt
;
1854 blk_status_t ret
= BLK_STS_OK
;
1855 LIST_HEAD(zone_list
);
1856 bool needs_resource
= false;
1858 if (list_empty(list
))
1862 * Now process all the entries, sending them to the driver.
1864 errors
= queued
= 0;
1866 struct blk_mq_queue_data bd
;
1868 rq
= list_first_entry(list
, struct request
, queuelist
);
1870 WARN_ON_ONCE(hctx
!= rq
->mq_hctx
);
1871 prep
= blk_mq_prep_dispatch_rq(rq
, !nr_budgets
);
1872 if (prep
!= PREP_DISPATCH_OK
)
1875 list_del_init(&rq
->queuelist
);
1880 * Flag last if we have no more requests, or if we have more
1881 * but can't assign a driver tag to it.
1883 if (list_empty(list
))
1886 nxt
= list_first_entry(list
, struct request
, queuelist
);
1887 bd
.last
= !blk_mq_get_driver_tag(nxt
);
1891 * once the request is queued to lld, no need to cover the
1896 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1901 case BLK_STS_RESOURCE
:
1902 needs_resource
= true;
1904 case BLK_STS_DEV_RESOURCE
:
1905 blk_mq_handle_dev_resource(rq
, list
);
1907 case BLK_STS_ZONE_RESOURCE
:
1909 * Move the request to zone_list and keep going through
1910 * the dispatch list to find more requests the drive can
1913 blk_mq_handle_zone_resource(rq
, &zone_list
);
1914 needs_resource
= true;
1918 blk_mq_end_request(rq
, ret
);
1920 } while (!list_empty(list
));
1922 if (!list_empty(&zone_list
))
1923 list_splice_tail_init(&zone_list
, list
);
1925 /* If we didn't flush the entire list, we could have told the driver
1926 * there was more coming, but that turned out to be a lie.
1928 if ((!list_empty(list
) || errors
) && q
->mq_ops
->commit_rqs
&& queued
)
1929 q
->mq_ops
->commit_rqs(hctx
);
1931 * Any items that need requeuing? Stuff them into hctx->dispatch,
1932 * that is where we will continue on next queue run.
1934 if (!list_empty(list
)) {
1936 /* For non-shared tags, the RESTART check will suffice */
1937 bool no_tag
= prep
== PREP_DISPATCH_NO_TAG
&&
1938 (hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
);
1941 blk_mq_release_budgets(q
, list
);
1943 spin_lock(&hctx
->lock
);
1944 list_splice_tail_init(list
, &hctx
->dispatch
);
1945 spin_unlock(&hctx
->lock
);
1948 * Order adding requests to hctx->dispatch and checking
1949 * SCHED_RESTART flag. The pair of this smp_mb() is the one
1950 * in blk_mq_sched_restart(). Avoid restart code path to
1951 * miss the new added requests to hctx->dispatch, meantime
1952 * SCHED_RESTART is observed here.
1957 * If SCHED_RESTART was set by the caller of this function and
1958 * it is no longer set that means that it was cleared by another
1959 * thread and hence that a queue rerun is needed.
1961 * If 'no_tag' is set, that means that we failed getting
1962 * a driver tag with an I/O scheduler attached. If our dispatch
1963 * waitqueue is no longer active, ensure that we run the queue
1964 * AFTER adding our entries back to the list.
1966 * If no I/O scheduler has been configured it is possible that
1967 * the hardware queue got stopped and restarted before requests
1968 * were pushed back onto the dispatch list. Rerun the queue to
1969 * avoid starvation. Notes:
1970 * - blk_mq_run_hw_queue() checks whether or not a queue has
1971 * been stopped before rerunning a queue.
1972 * - Some but not all block drivers stop a queue before
1973 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
1976 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
1977 * bit is set, run queue after a delay to avoid IO stalls
1978 * that could otherwise occur if the queue is idle. We'll do
1979 * similar if we couldn't get budget or couldn't lock a zone
1980 * and SCHED_RESTART is set.
1982 needs_restart
= blk_mq_sched_needs_restart(hctx
);
1983 if (prep
== PREP_DISPATCH_NO_BUDGET
)
1984 needs_resource
= true;
1985 if (!needs_restart
||
1986 (no_tag
&& list_empty_careful(&hctx
->dispatch_wait
.entry
)))
1987 blk_mq_run_hw_queue(hctx
, true);
1988 else if (needs_restart
&& needs_resource
)
1989 blk_mq_delay_run_hw_queue(hctx
, BLK_MQ_RESOURCE_DELAY
);
1991 blk_mq_update_dispatch_busy(hctx
, true);
1994 blk_mq_update_dispatch_busy(hctx
, false);
1996 return (queued
+ errors
) != 0;
2000 * __blk_mq_run_hw_queue - Run a hardware queue.
2001 * @hctx: Pointer to the hardware queue to run.
2003 * Send pending requests to the hardware.
2005 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
2008 * We can't run the queue inline with ints disabled. Ensure that
2009 * we catch bad users of this early.
2011 WARN_ON_ONCE(in_interrupt());
2013 blk_mq_run_dispatch_ops(hctx
->queue
,
2014 blk_mq_sched_dispatch_requests(hctx
));
2017 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx
*hctx
)
2019 int cpu
= cpumask_first_and(hctx
->cpumask
, cpu_online_mask
);
2021 if (cpu
>= nr_cpu_ids
)
2022 cpu
= cpumask_first(hctx
->cpumask
);
2027 * It'd be great if the workqueue API had a way to pass
2028 * in a mask and had some smarts for more clever placement.
2029 * For now we just round-robin here, switching for every
2030 * BLK_MQ_CPU_WORK_BATCH queued items.
2032 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
2035 int next_cpu
= hctx
->next_cpu
;
2037 if (hctx
->queue
->nr_hw_queues
== 1)
2038 return WORK_CPU_UNBOUND
;
2040 if (--hctx
->next_cpu_batch
<= 0) {
2042 next_cpu
= cpumask_next_and(next_cpu
, hctx
->cpumask
,
2044 if (next_cpu
>= nr_cpu_ids
)
2045 next_cpu
= blk_mq_first_mapped_cpu(hctx
);
2046 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
2050 * Do unbound schedule if we can't find a online CPU for this hctx,
2051 * and it should only happen in the path of handling CPU DEAD.
2053 if (!cpu_online(next_cpu
)) {
2060 * Make sure to re-select CPU next time once after CPUs
2061 * in hctx->cpumask become online again.
2063 hctx
->next_cpu
= next_cpu
;
2064 hctx
->next_cpu_batch
= 1;
2065 return WORK_CPU_UNBOUND
;
2068 hctx
->next_cpu
= next_cpu
;
2073 * __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue.
2074 * @hctx: Pointer to the hardware queue to run.
2075 * @async: If we want to run the queue asynchronously.
2076 * @msecs: Milliseconds of delay to wait before running the queue.
2078 * If !@async, try to run the queue now. Else, run the queue asynchronously and
2079 * with a delay of @msecs.
2081 static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
,
2082 unsigned long msecs
)
2084 if (unlikely(blk_mq_hctx_stopped(hctx
)))
2087 if (!async
&& !(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
2088 int cpu
= get_cpu();
2089 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
2090 __blk_mq_run_hw_queue(hctx
);
2098 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx
), &hctx
->run_work
,
2099 msecs_to_jiffies(msecs
));
2103 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
2104 * @hctx: Pointer to the hardware queue to run.
2105 * @msecs: Milliseconds of delay to wait before running the queue.
2107 * Run a hardware queue asynchronously with a delay of @msecs.
2109 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
2111 __blk_mq_delay_run_hw_queue(hctx
, true, msecs
);
2113 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue
);
2116 * blk_mq_run_hw_queue - Start to run a hardware queue.
2117 * @hctx: Pointer to the hardware queue to run.
2118 * @async: If we want to run the queue asynchronously.
2120 * Check if the request queue is not in a quiesced state and if there are
2121 * pending requests to be sent. If this is true, run the queue to send requests
2124 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
2129 * When queue is quiesced, we may be switching io scheduler, or
2130 * updating nr_hw_queues, or other things, and we can't run queue
2131 * any more, even __blk_mq_hctx_has_pending() can't be called safely.
2133 * And queue will be rerun in blk_mq_unquiesce_queue() if it is
2136 __blk_mq_run_dispatch_ops(hctx
->queue
, false,
2137 need_run
= !blk_queue_quiesced(hctx
->queue
) &&
2138 blk_mq_hctx_has_pending(hctx
));
2141 __blk_mq_delay_run_hw_queue(hctx
, async
, 0);
2143 EXPORT_SYMBOL(blk_mq_run_hw_queue
);
2146 * Return prefered queue to dispatch from (if any) for non-mq aware IO
2149 static struct blk_mq_hw_ctx
*blk_mq_get_sq_hctx(struct request_queue
*q
)
2151 struct blk_mq_ctx
*ctx
= blk_mq_get_ctx(q
);
2153 * If the IO scheduler does not respect hardware queues when
2154 * dispatching, we just don't bother with multiple HW queues and
2155 * dispatch from hctx for the current CPU since running multiple queues
2156 * just causes lock contention inside the scheduler and pointless cache
2159 struct blk_mq_hw_ctx
*hctx
= blk_mq_map_queue(q
, 0, ctx
);
2161 if (!blk_mq_hctx_stopped(hctx
))
2167 * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
2168 * @q: Pointer to the request queue to run.
2169 * @async: If we want to run the queue asynchronously.
2171 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
2173 struct blk_mq_hw_ctx
*hctx
, *sq_hctx
;
2177 if (blk_queue_sq_sched(q
))
2178 sq_hctx
= blk_mq_get_sq_hctx(q
);
2179 queue_for_each_hw_ctx(q
, hctx
, i
) {
2180 if (blk_mq_hctx_stopped(hctx
))
2183 * Dispatch from this hctx either if there's no hctx preferred
2184 * by IO scheduler or if it has requests that bypass the
2187 if (!sq_hctx
|| sq_hctx
== hctx
||
2188 !list_empty_careful(&hctx
->dispatch
))
2189 blk_mq_run_hw_queue(hctx
, async
);
2192 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
2195 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
2196 * @q: Pointer to the request queue to run.
2197 * @msecs: Milliseconds of delay to wait before running the queues.
2199 void blk_mq_delay_run_hw_queues(struct request_queue
*q
, unsigned long msecs
)
2201 struct blk_mq_hw_ctx
*hctx
, *sq_hctx
;
2205 if (blk_queue_sq_sched(q
))
2206 sq_hctx
= blk_mq_get_sq_hctx(q
);
2207 queue_for_each_hw_ctx(q
, hctx
, i
) {
2208 if (blk_mq_hctx_stopped(hctx
))
2211 * If there is already a run_work pending, leave the
2212 * pending delay untouched. Otherwise, a hctx can stall
2213 * if another hctx is re-delaying the other's work
2214 * before the work executes.
2216 if (delayed_work_pending(&hctx
->run_work
))
2219 * Dispatch from this hctx either if there's no hctx preferred
2220 * by IO scheduler or if it has requests that bypass the
2223 if (!sq_hctx
|| sq_hctx
== hctx
||
2224 !list_empty_careful(&hctx
->dispatch
))
2225 blk_mq_delay_run_hw_queue(hctx
, msecs
);
2228 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues
);
2231 * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
2232 * @q: request queue.
2234 * The caller is responsible for serializing this function against
2235 * blk_mq_{start,stop}_hw_queue().
2237 bool blk_mq_queue_stopped(struct request_queue
*q
)
2239 struct blk_mq_hw_ctx
*hctx
;
2242 queue_for_each_hw_ctx(q
, hctx
, i
)
2243 if (blk_mq_hctx_stopped(hctx
))
2248 EXPORT_SYMBOL(blk_mq_queue_stopped
);
2251 * This function is often used for pausing .queue_rq() by driver when
2252 * there isn't enough resource or some conditions aren't satisfied, and
2253 * BLK_STS_RESOURCE is usually returned.
2255 * We do not guarantee that dispatch can be drained or blocked
2256 * after blk_mq_stop_hw_queue() returns. Please use
2257 * blk_mq_quiesce_queue() for that requirement.
2259 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
2261 cancel_delayed_work(&hctx
->run_work
);
2263 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
2265 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
2268 * This function is often used for pausing .queue_rq() by driver when
2269 * there isn't enough resource or some conditions aren't satisfied, and
2270 * BLK_STS_RESOURCE is usually returned.
2272 * We do not guarantee that dispatch can be drained or blocked
2273 * after blk_mq_stop_hw_queues() returns. Please use
2274 * blk_mq_quiesce_queue() for that requirement.
2276 void blk_mq_stop_hw_queues(struct request_queue
*q
)
2278 struct blk_mq_hw_ctx
*hctx
;
2281 queue_for_each_hw_ctx(q
, hctx
, i
)
2282 blk_mq_stop_hw_queue(hctx
);
2284 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
2286 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
2288 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
2290 blk_mq_run_hw_queue(hctx
, false);
2292 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
2294 void blk_mq_start_hw_queues(struct request_queue
*q
)
2296 struct blk_mq_hw_ctx
*hctx
;
2299 queue_for_each_hw_ctx(q
, hctx
, i
)
2300 blk_mq_start_hw_queue(hctx
);
2302 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
2304 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
2306 if (!blk_mq_hctx_stopped(hctx
))
2309 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
2310 blk_mq_run_hw_queue(hctx
, async
);
2312 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue
);
2314 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
2316 struct blk_mq_hw_ctx
*hctx
;
2319 queue_for_each_hw_ctx(q
, hctx
, i
)
2320 blk_mq_start_stopped_hw_queue(hctx
, async
);
2322 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
2324 static void blk_mq_run_work_fn(struct work_struct
*work
)
2326 struct blk_mq_hw_ctx
*hctx
;
2328 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
2331 * If we are stopped, don't run the queue.
2333 if (blk_mq_hctx_stopped(hctx
))
2336 __blk_mq_run_hw_queue(hctx
);
2339 static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx
*hctx
,
2343 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
2344 enum hctx_type type
= hctx
->type
;
2346 lockdep_assert_held(&ctx
->lock
);
2348 trace_block_rq_insert(rq
);
2351 list_add(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
2353 list_add_tail(&rq
->queuelist
, &ctx
->rq_lists
[type
]);
2356 void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
2359 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
2361 lockdep_assert_held(&ctx
->lock
);
2363 __blk_mq_insert_req_list(hctx
, rq
, at_head
);
2364 blk_mq_hctx_mark_pending(hctx
, ctx
);
2368 * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2369 * @rq: Pointer to request to be inserted.
2370 * @at_head: true if the request should be inserted at the head of the list.
2371 * @run_queue: If we should run the hardware queue after inserting the request.
2373 * Should only be used carefully, when the caller knows we want to
2374 * bypass a potential IO scheduler on the target device.
2376 void blk_mq_request_bypass_insert(struct request
*rq
, bool at_head
,
2379 struct blk_mq_hw_ctx
*hctx
= rq
->mq_hctx
;
2381 spin_lock(&hctx
->lock
);
2383 list_add(&rq
->queuelist
, &hctx
->dispatch
);
2385 list_add_tail(&rq
->queuelist
, &hctx
->dispatch
);
2386 spin_unlock(&hctx
->lock
);
2389 blk_mq_run_hw_queue(hctx
, false);
2392 void blk_mq_insert_requests(struct blk_mq_hw_ctx
*hctx
, struct blk_mq_ctx
*ctx
,
2393 struct list_head
*list
)
2397 enum hctx_type type
= hctx
->type
;
2400 * preemption doesn't flush plug list, so it's possible ctx->cpu is
2403 list_for_each_entry(rq
, list
, queuelist
) {
2404 BUG_ON(rq
->mq_ctx
!= ctx
);
2405 trace_block_rq_insert(rq
);
2408 spin_lock(&ctx
->lock
);
2409 list_splice_tail_init(list
, &ctx
->rq_lists
[type
]);
2410 blk_mq_hctx_mark_pending(hctx
, ctx
);
2411 spin_unlock(&ctx
->lock
);
2414 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx
*hctx
, int *queued
,
2417 if (hctx
->queue
->mq_ops
->commit_rqs
) {
2418 trace_block_unplug(hctx
->queue
, *queued
, !from_schedule
);
2419 hctx
->queue
->mq_ops
->commit_rqs(hctx
);
2424 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
,
2425 unsigned int nr_segs
)
2429 if (bio
->bi_opf
& REQ_RAHEAD
)
2430 rq
->cmd_flags
|= REQ_FAILFAST_MASK
;
2432 rq
->__sector
= bio
->bi_iter
.bi_sector
;
2433 blk_rq_bio_prep(rq
, bio
, nr_segs
);
2435 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2436 err
= blk_crypto_rq_bio_prep(rq
, bio
, GFP_NOIO
);
2439 blk_account_io_start(rq
);
2442 static blk_status_t
__blk_mq_issue_directly(struct blk_mq_hw_ctx
*hctx
,
2443 struct request
*rq
, bool last
)
2445 struct request_queue
*q
= rq
->q
;
2446 struct blk_mq_queue_data bd
= {
2453 * For OK queue, we are done. For error, caller may kill it.
2454 * Any other error (busy), just add it to our list as we
2455 * previously would have done.
2457 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
2460 blk_mq_update_dispatch_busy(hctx
, false);
2462 case BLK_STS_RESOURCE
:
2463 case BLK_STS_DEV_RESOURCE
:
2464 blk_mq_update_dispatch_busy(hctx
, true);
2465 __blk_mq_requeue_request(rq
);
2468 blk_mq_update_dispatch_busy(hctx
, false);
2475 static blk_status_t
__blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
2477 bool bypass_insert
, bool last
)
2479 struct request_queue
*q
= rq
->q
;
2480 bool run_queue
= true;
2484 * RCU or SRCU read lock is needed before checking quiesced flag.
2486 * When queue is stopped or quiesced, ignore 'bypass_insert' from
2487 * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller,
2488 * and avoid driver to try to dispatch again.
2490 if (blk_mq_hctx_stopped(hctx
) || blk_queue_quiesced(q
)) {
2492 bypass_insert
= false;
2496 if ((rq
->rq_flags
& RQF_ELV
) && !bypass_insert
)
2499 budget_token
= blk_mq_get_dispatch_budget(q
);
2500 if (budget_token
< 0)
2503 blk_mq_set_rq_budget_token(rq
, budget_token
);
2505 if (!blk_mq_get_driver_tag(rq
)) {
2506 blk_mq_put_dispatch_budget(q
, budget_token
);
2510 return __blk_mq_issue_directly(hctx
, rq
, last
);
2513 return BLK_STS_RESOURCE
;
2515 blk_mq_sched_insert_request(rq
, false, run_queue
, false);
2521 * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2522 * @hctx: Pointer of the associated hardware queue.
2523 * @rq: Pointer to request to be sent.
2525 * If the device has enough resources to accept a new request now, send the
2526 * request directly to device driver. Else, insert at hctx->dispatch queue, so
2527 * we can try send it another time in the future. Requests inserted at this
2528 * queue have higher priority.
2530 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
2534 __blk_mq_try_issue_directly(hctx
, rq
, false, true);
2536 if (ret
== BLK_STS_RESOURCE
|| ret
== BLK_STS_DEV_RESOURCE
)
2537 blk_mq_request_bypass_insert(rq
, false, true);
2538 else if (ret
!= BLK_STS_OK
)
2539 blk_mq_end_request(rq
, ret
);
2542 static blk_status_t
blk_mq_request_issue_directly(struct request
*rq
, bool last
)
2544 return __blk_mq_try_issue_directly(rq
->mq_hctx
, rq
, true, last
);
2547 static void blk_mq_plug_issue_direct(struct blk_plug
*plug
, bool from_schedule
)
2549 struct blk_mq_hw_ctx
*hctx
= NULL
;
2554 while ((rq
= rq_list_pop(&plug
->mq_list
))) {
2555 bool last
= rq_list_empty(plug
->mq_list
);
2558 if (hctx
!= rq
->mq_hctx
) {
2560 blk_mq_commit_rqs(hctx
, &queued
, from_schedule
);
2564 ret
= blk_mq_request_issue_directly(rq
, last
);
2569 case BLK_STS_RESOURCE
:
2570 case BLK_STS_DEV_RESOURCE
:
2571 blk_mq_request_bypass_insert(rq
, false, last
);
2572 blk_mq_commit_rqs(hctx
, &queued
, from_schedule
);
2575 blk_mq_end_request(rq
, ret
);
2582 * If we didn't flush the entire list, we could have told the driver
2583 * there was more coming, but that turned out to be a lie.
2586 blk_mq_commit_rqs(hctx
, &queued
, from_schedule
);
2589 static void __blk_mq_flush_plug_list(struct request_queue
*q
,
2590 struct blk_plug
*plug
)
2592 if (blk_queue_quiesced(q
))
2594 q
->mq_ops
->queue_rqs(&plug
->mq_list
);
2597 static void blk_mq_dispatch_plug_list(struct blk_plug
*plug
, bool from_sched
)
2599 struct blk_mq_hw_ctx
*this_hctx
= NULL
;
2600 struct blk_mq_ctx
*this_ctx
= NULL
;
2601 struct request
*requeue_list
= NULL
;
2602 unsigned int depth
= 0;
2606 struct request
*rq
= rq_list_pop(&plug
->mq_list
);
2609 this_hctx
= rq
->mq_hctx
;
2610 this_ctx
= rq
->mq_ctx
;
2611 } else if (this_hctx
!= rq
->mq_hctx
|| this_ctx
!= rq
->mq_ctx
) {
2612 rq_list_add(&requeue_list
, rq
);
2615 list_add_tail(&rq
->queuelist
, &list
);
2617 } while (!rq_list_empty(plug
->mq_list
));
2619 plug
->mq_list
= requeue_list
;
2620 trace_block_unplug(this_hctx
->queue
, depth
, !from_sched
);
2621 blk_mq_sched_insert_requests(this_hctx
, this_ctx
, &list
, from_sched
);
2624 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
2628 if (rq_list_empty(plug
->mq_list
))
2632 if (!plug
->multiple_queues
&& !plug
->has_elevator
&& !from_schedule
) {
2633 struct request_queue
*q
;
2635 rq
= rq_list_peek(&plug
->mq_list
);
2639 * Peek first request and see if we have a ->queue_rqs() hook.
2640 * If we do, we can dispatch the whole plug list in one go. We
2641 * already know at this point that all requests belong to the
2642 * same queue, caller must ensure that's the case.
2644 * Since we pass off the full list to the driver at this point,
2645 * we do not increment the active request count for the queue.
2646 * Bypass shared tags for now because of that.
2648 if (q
->mq_ops
->queue_rqs
&&
2649 !(rq
->mq_hctx
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)) {
2650 blk_mq_run_dispatch_ops(q
,
2651 __blk_mq_flush_plug_list(q
, plug
));
2652 if (rq_list_empty(plug
->mq_list
))
2656 blk_mq_run_dispatch_ops(q
,
2657 blk_mq_plug_issue_direct(plug
, false));
2658 if (rq_list_empty(plug
->mq_list
))
2663 blk_mq_dispatch_plug_list(plug
, from_schedule
);
2664 } while (!rq_list_empty(plug
->mq_list
));
2667 void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx
*hctx
,
2668 struct list_head
*list
)
2673 while (!list_empty(list
)) {
2675 struct request
*rq
= list_first_entry(list
, struct request
,
2678 list_del_init(&rq
->queuelist
);
2679 ret
= blk_mq_request_issue_directly(rq
, list_empty(list
));
2680 if (ret
!= BLK_STS_OK
) {
2681 if (ret
== BLK_STS_RESOURCE
||
2682 ret
== BLK_STS_DEV_RESOURCE
) {
2683 blk_mq_request_bypass_insert(rq
, false,
2687 blk_mq_end_request(rq
, ret
);
2694 * If we didn't flush the entire list, we could have told
2695 * the driver there was more coming, but that turned out to
2698 if ((!list_empty(list
) || errors
) &&
2699 hctx
->queue
->mq_ops
->commit_rqs
&& queued
)
2700 hctx
->queue
->mq_ops
->commit_rqs(hctx
);
2703 static bool blk_mq_attempt_bio_merge(struct request_queue
*q
,
2704 struct bio
*bio
, unsigned int nr_segs
)
2706 if (!blk_queue_nomerges(q
) && bio_mergeable(bio
)) {
2707 if (blk_attempt_plug_merge(q
, bio
, nr_segs
))
2709 if (blk_mq_sched_bio_merge(q
, bio
, nr_segs
))
2715 static struct request
*blk_mq_get_new_requests(struct request_queue
*q
,
2716 struct blk_plug
*plug
,
2720 struct blk_mq_alloc_data data
= {
2723 .cmd_flags
= bio
->bi_opf
,
2727 if (unlikely(bio_queue_enter(bio
)))
2730 if (blk_mq_attempt_bio_merge(q
, bio
, nsegs
))
2733 rq_qos_throttle(q
, bio
);
2736 data
.nr_tags
= plug
->nr_ios
;
2738 data
.cached_rq
= &plug
->cached_rq
;
2741 rq
= __blk_mq_alloc_requests(&data
);
2744 rq_qos_cleanup(q
, bio
);
2745 if (bio
->bi_opf
& REQ_NOWAIT
)
2746 bio_wouldblock_error(bio
);
2752 static inline struct request
*blk_mq_get_cached_request(struct request_queue
*q
,
2753 struct blk_plug
*plug
, struct bio
**bio
, unsigned int nsegs
)
2759 rq
= rq_list_peek(&plug
->cached_rq
);
2760 if (!rq
|| rq
->q
!= q
)
2763 if (blk_mq_attempt_bio_merge(q
, *bio
, nsegs
)) {
2768 if (blk_mq_get_hctx_type((*bio
)->bi_opf
) != rq
->mq_hctx
->type
)
2770 if (op_is_flush(rq
->cmd_flags
) != op_is_flush((*bio
)->bi_opf
))
2774 * If any qos ->throttle() end up blocking, we will have flushed the
2775 * plug and hence killed the cached_rq list as well. Pop this entry
2776 * before we throttle.
2778 plug
->cached_rq
= rq_list_next(rq
);
2779 rq_qos_throttle(q
, *bio
);
2781 rq
->cmd_flags
= (*bio
)->bi_opf
;
2782 INIT_LIST_HEAD(&rq
->queuelist
);
2787 * blk_mq_submit_bio - Create and send a request to block device.
2788 * @bio: Bio pointer.
2790 * Builds up a request structure from @q and @bio and send to the device. The
2791 * request may not be queued directly to hardware if:
2792 * * This request can be merged with another one
2793 * * We want to place request at plug queue for possible future merging
2794 * * There is an IO scheduler active at this queue
2796 * It will not queue the request if there is an error with the bio, or at the
2799 void blk_mq_submit_bio(struct bio
*bio
)
2801 struct request_queue
*q
= bdev_get_queue(bio
->bi_bdev
);
2802 struct blk_plug
*plug
= blk_mq_plug(q
, bio
);
2803 const int is_sync
= op_is_sync(bio
->bi_opf
);
2805 unsigned int nr_segs
= 1;
2808 blk_queue_bounce(q
, &bio
);
2809 if (blk_may_split(q
, bio
))
2810 __blk_queue_split(q
, &bio
, &nr_segs
);
2812 if (!bio_integrity_prep(bio
))
2815 rq
= blk_mq_get_cached_request(q
, plug
, &bio
, nr_segs
);
2819 rq
= blk_mq_get_new_requests(q
, plug
, bio
, nr_segs
);
2824 trace_block_getrq(bio
);
2826 rq_qos_track(q
, rq
, bio
);
2828 blk_mq_bio_to_request(rq
, bio
, nr_segs
);
2830 ret
= blk_crypto_init_request(rq
);
2831 if (ret
!= BLK_STS_OK
) {
2832 bio
->bi_status
= ret
;
2834 blk_mq_free_request(rq
);
2838 if (op_is_flush(bio
->bi_opf
)) {
2839 blk_insert_flush(rq
);
2844 blk_add_rq_to_plug(plug
, rq
);
2845 else if ((rq
->rq_flags
& RQF_ELV
) ||
2846 (rq
->mq_hctx
->dispatch_busy
&&
2847 (q
->nr_hw_queues
== 1 || !is_sync
)))
2848 blk_mq_sched_insert_request(rq
, false, true, true);
2850 blk_mq_run_dispatch_ops(rq
->q
,
2851 blk_mq_try_issue_directly(rq
->mq_hctx
, rq
));
2854 #ifdef CONFIG_BLK_MQ_STACKING
2856 * blk_insert_cloned_request - Helper for stacking drivers to submit a request
2857 * @rq: the request being queued
2859 blk_status_t
blk_insert_cloned_request(struct request
*rq
)
2861 struct request_queue
*q
= rq
->q
;
2862 unsigned int max_sectors
= blk_queue_get_max_sectors(q
, req_op(rq
));
2865 if (blk_rq_sectors(rq
) > max_sectors
) {
2867 * SCSI device does not have a good way to return if
2868 * Write Same/Zero is actually supported. If a device rejects
2869 * a non-read/write command (discard, write same,etc.) the
2870 * low-level device driver will set the relevant queue limit to
2871 * 0 to prevent blk-lib from issuing more of the offending
2872 * operations. Commands queued prior to the queue limit being
2873 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
2874 * errors being propagated to upper layers.
2876 if (max_sectors
== 0)
2877 return BLK_STS_NOTSUPP
;
2879 printk(KERN_ERR
"%s: over max size limit. (%u > %u)\n",
2880 __func__
, blk_rq_sectors(rq
), max_sectors
);
2881 return BLK_STS_IOERR
;
2885 * The queue settings related to segment counting may differ from the
2888 rq
->nr_phys_segments
= blk_recalc_rq_segments(rq
);
2889 if (rq
->nr_phys_segments
> queue_max_segments(q
)) {
2890 printk(KERN_ERR
"%s: over max segments limit. (%hu > %hu)\n",
2891 __func__
, rq
->nr_phys_segments
, queue_max_segments(q
));
2892 return BLK_STS_IOERR
;
2895 if (q
->disk
&& should_fail_request(q
->disk
->part0
, blk_rq_bytes(rq
)))
2896 return BLK_STS_IOERR
;
2898 if (blk_crypto_insert_cloned_request(rq
))
2899 return BLK_STS_IOERR
;
2901 blk_account_io_start(rq
);
2904 * Since we have a scheduler attached on the top device,
2905 * bypass a potential scheduler on the bottom device for
2908 blk_mq_run_dispatch_ops(q
,
2909 ret
= blk_mq_request_issue_directly(rq
, true));
2911 blk_account_io_done(rq
, ktime_get_ns());
2914 EXPORT_SYMBOL_GPL(blk_insert_cloned_request
);
2917 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
2918 * @rq: the clone request to be cleaned up
2921 * Free all bios in @rq for a cloned request.
2923 void blk_rq_unprep_clone(struct request
*rq
)
2927 while ((bio
= rq
->bio
) != NULL
) {
2928 rq
->bio
= bio
->bi_next
;
2933 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone
);
2936 * blk_rq_prep_clone - Helper function to setup clone request
2937 * @rq: the request to be setup
2938 * @rq_src: original request to be cloned
2939 * @bs: bio_set that bios for clone are allocated from
2940 * @gfp_mask: memory allocation mask for bio
2941 * @bio_ctr: setup function to be called for each clone bio.
2942 * Returns %0 for success, non %0 for failure.
2943 * @data: private data to be passed to @bio_ctr
2946 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
2947 * Also, pages which the original bios are pointing to are not copied
2948 * and the cloned bios just point same pages.
2949 * So cloned bios must be completed before original bios, which means
2950 * the caller must complete @rq before @rq_src.
2952 int blk_rq_prep_clone(struct request
*rq
, struct request
*rq_src
,
2953 struct bio_set
*bs
, gfp_t gfp_mask
,
2954 int (*bio_ctr
)(struct bio
*, struct bio
*, void *),
2957 struct bio
*bio
, *bio_src
;
2962 __rq_for_each_bio(bio_src
, rq_src
) {
2963 bio
= bio_alloc_clone(rq
->q
->disk
->part0
, bio_src
, gfp_mask
,
2968 if (bio_ctr
&& bio_ctr(bio
, bio_src
, data
))
2972 rq
->biotail
->bi_next
= bio
;
2975 rq
->bio
= rq
->biotail
= bio
;
2980 /* Copy attributes of the original request to the clone request. */
2981 rq
->__sector
= blk_rq_pos(rq_src
);
2982 rq
->__data_len
= blk_rq_bytes(rq_src
);
2983 if (rq_src
->rq_flags
& RQF_SPECIAL_PAYLOAD
) {
2984 rq
->rq_flags
|= RQF_SPECIAL_PAYLOAD
;
2985 rq
->special_vec
= rq_src
->special_vec
;
2987 rq
->nr_phys_segments
= rq_src
->nr_phys_segments
;
2988 rq
->ioprio
= rq_src
->ioprio
;
2990 if (rq
->bio
&& blk_crypto_rq_bio_prep(rq
, rq
->bio
, gfp_mask
) < 0)
2998 blk_rq_unprep_clone(rq
);
3002 EXPORT_SYMBOL_GPL(blk_rq_prep_clone
);
3003 #endif /* CONFIG_BLK_MQ_STACKING */
3006 * Steal bios from a request and add them to a bio list.
3007 * The request must not have been partially completed before.
3009 void blk_steal_bios(struct bio_list
*list
, struct request
*rq
)
3013 list
->tail
->bi_next
= rq
->bio
;
3015 list
->head
= rq
->bio
;
3016 list
->tail
= rq
->biotail
;
3024 EXPORT_SYMBOL_GPL(blk_steal_bios
);
3026 static size_t order_to_size(unsigned int order
)
3028 return (size_t)PAGE_SIZE
<< order
;
3031 /* called before freeing request pool in @tags */
3032 static void blk_mq_clear_rq_mapping(struct blk_mq_tags
*drv_tags
,
3033 struct blk_mq_tags
*tags
)
3036 unsigned long flags
;
3038 /* There is no need to clear a driver tags own mapping */
3039 if (drv_tags
== tags
)
3042 list_for_each_entry(page
, &tags
->page_list
, lru
) {
3043 unsigned long start
= (unsigned long)page_address(page
);
3044 unsigned long end
= start
+ order_to_size(page
->private);
3047 for (i
= 0; i
< drv_tags
->nr_tags
; i
++) {
3048 struct request
*rq
= drv_tags
->rqs
[i
];
3049 unsigned long rq_addr
= (unsigned long)rq
;
3051 if (rq_addr
>= start
&& rq_addr
< end
) {
3052 WARN_ON_ONCE(req_ref_read(rq
) != 0);
3053 cmpxchg(&drv_tags
->rqs
[i
], rq
, NULL
);
3059 * Wait until all pending iteration is done.
3061 * Request reference is cleared and it is guaranteed to be observed
3062 * after the ->lock is released.
3064 spin_lock_irqsave(&drv_tags
->lock
, flags
);
3065 spin_unlock_irqrestore(&drv_tags
->lock
, flags
);
3068 void blk_mq_free_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
3069 unsigned int hctx_idx
)
3071 struct blk_mq_tags
*drv_tags
;
3074 if (list_empty(&tags
->page_list
))
3077 if (blk_mq_is_shared_tags(set
->flags
))
3078 drv_tags
= set
->shared_tags
;
3080 drv_tags
= set
->tags
[hctx_idx
];
3082 if (tags
->static_rqs
&& set
->ops
->exit_request
) {
3085 for (i
= 0; i
< tags
->nr_tags
; i
++) {
3086 struct request
*rq
= tags
->static_rqs
[i
];
3090 set
->ops
->exit_request(set
, rq
, hctx_idx
);
3091 tags
->static_rqs
[i
] = NULL
;
3095 blk_mq_clear_rq_mapping(drv_tags
, tags
);
3097 while (!list_empty(&tags
->page_list
)) {
3098 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
3099 list_del_init(&page
->lru
);
3101 * Remove kmemleak object previously allocated in
3102 * blk_mq_alloc_rqs().
3104 kmemleak_free(page_address(page
));
3105 __free_pages(page
, page
->private);
3109 void blk_mq_free_rq_map(struct blk_mq_tags
*tags
)
3113 kfree(tags
->static_rqs
);
3114 tags
->static_rqs
= NULL
;
3116 blk_mq_free_tags(tags
);
3119 static enum hctx_type
hctx_idx_to_type(struct blk_mq_tag_set
*set
,
3120 unsigned int hctx_idx
)
3124 for (i
= 0; i
< set
->nr_maps
; i
++) {
3125 unsigned int start
= set
->map
[i
].queue_offset
;
3126 unsigned int end
= start
+ set
->map
[i
].nr_queues
;
3128 if (hctx_idx
>= start
&& hctx_idx
< end
)
3132 if (i
>= set
->nr_maps
)
3133 i
= HCTX_TYPE_DEFAULT
;
3138 static int blk_mq_get_hctx_node(struct blk_mq_tag_set
*set
,
3139 unsigned int hctx_idx
)
3141 enum hctx_type type
= hctx_idx_to_type(set
, hctx_idx
);
3143 return blk_mq_hw_queue_to_node(&set
->map
[type
], hctx_idx
);
3146 static struct blk_mq_tags
*blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
,
3147 unsigned int hctx_idx
,
3148 unsigned int nr_tags
,
3149 unsigned int reserved_tags
)
3151 int node
= blk_mq_get_hctx_node(set
, hctx_idx
);
3152 struct blk_mq_tags
*tags
;
3154 if (node
== NUMA_NO_NODE
)
3155 node
= set
->numa_node
;
3157 tags
= blk_mq_init_tags(nr_tags
, reserved_tags
, node
,
3158 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
3162 tags
->rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
3163 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
3166 blk_mq_free_tags(tags
);
3170 tags
->static_rqs
= kcalloc_node(nr_tags
, sizeof(struct request
*),
3171 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
3173 if (!tags
->static_rqs
) {
3175 blk_mq_free_tags(tags
);
3182 static int blk_mq_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
3183 unsigned int hctx_idx
, int node
)
3187 if (set
->ops
->init_request
) {
3188 ret
= set
->ops
->init_request(set
, rq
, hctx_idx
, node
);
3193 WRITE_ONCE(rq
->state
, MQ_RQ_IDLE
);
3197 static int blk_mq_alloc_rqs(struct blk_mq_tag_set
*set
,
3198 struct blk_mq_tags
*tags
,
3199 unsigned int hctx_idx
, unsigned int depth
)
3201 unsigned int i
, j
, entries_per_page
, max_order
= 4;
3202 int node
= blk_mq_get_hctx_node(set
, hctx_idx
);
3203 size_t rq_size
, left
;
3205 if (node
== NUMA_NO_NODE
)
3206 node
= set
->numa_node
;
3208 INIT_LIST_HEAD(&tags
->page_list
);
3211 * rq_size is the size of the request plus driver payload, rounded
3212 * to the cacheline size
3214 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
3216 left
= rq_size
* depth
;
3218 for (i
= 0; i
< depth
; ) {
3219 int this_order
= max_order
;
3224 while (this_order
&& left
< order_to_size(this_order
- 1))
3228 page
= alloc_pages_node(node
,
3229 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
3235 if (order_to_size(this_order
) < rq_size
)
3242 page
->private = this_order
;
3243 list_add_tail(&page
->lru
, &tags
->page_list
);
3245 p
= page_address(page
);
3247 * Allow kmemleak to scan these pages as they contain pointers
3248 * to additional allocations like via ops->init_request().
3250 kmemleak_alloc(p
, order_to_size(this_order
), 1, GFP_NOIO
);
3251 entries_per_page
= order_to_size(this_order
) / rq_size
;
3252 to_do
= min(entries_per_page
, depth
- i
);
3253 left
-= to_do
* rq_size
;
3254 for (j
= 0; j
< to_do
; j
++) {
3255 struct request
*rq
= p
;
3257 tags
->static_rqs
[i
] = rq
;
3258 if (blk_mq_init_request(set
, rq
, hctx_idx
, node
)) {
3259 tags
->static_rqs
[i
] = NULL
;
3270 blk_mq_free_rqs(set
, tags
, hctx_idx
);
3274 struct rq_iter_data
{
3275 struct blk_mq_hw_ctx
*hctx
;
3279 static bool blk_mq_has_request(struct request
*rq
, void *data
, bool reserved
)
3281 struct rq_iter_data
*iter_data
= data
;
3283 if (rq
->mq_hctx
!= iter_data
->hctx
)
3285 iter_data
->has_rq
= true;
3289 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx
*hctx
)
3291 struct blk_mq_tags
*tags
= hctx
->sched_tags
?
3292 hctx
->sched_tags
: hctx
->tags
;
3293 struct rq_iter_data data
= {
3297 blk_mq_all_tag_iter(tags
, blk_mq_has_request
, &data
);
3301 static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu
,
3302 struct blk_mq_hw_ctx
*hctx
)
3304 if (cpumask_first_and(hctx
->cpumask
, cpu_online_mask
) != cpu
)
3306 if (cpumask_next_and(cpu
, hctx
->cpumask
, cpu_online_mask
) < nr_cpu_ids
)
3311 static int blk_mq_hctx_notify_offline(unsigned int cpu
, struct hlist_node
*node
)
3313 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
3314 struct blk_mq_hw_ctx
, cpuhp_online
);
3316 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
) ||
3317 !blk_mq_last_cpu_in_hctx(cpu
, hctx
))
3321 * Prevent new request from being allocated on the current hctx.
3323 * The smp_mb__after_atomic() Pairs with the implied barrier in
3324 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
3325 * seen once we return from the tag allocator.
3327 set_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
3328 smp_mb__after_atomic();
3331 * Try to grab a reference to the queue and wait for any outstanding
3332 * requests. If we could not grab a reference the queue has been
3333 * frozen and there are no requests.
3335 if (percpu_ref_tryget(&hctx
->queue
->q_usage_counter
)) {
3336 while (blk_mq_hctx_has_requests(hctx
))
3338 percpu_ref_put(&hctx
->queue
->q_usage_counter
);
3344 static int blk_mq_hctx_notify_online(unsigned int cpu
, struct hlist_node
*node
)
3346 struct blk_mq_hw_ctx
*hctx
= hlist_entry_safe(node
,
3347 struct blk_mq_hw_ctx
, cpuhp_online
);
3349 if (cpumask_test_cpu(cpu
, hctx
->cpumask
))
3350 clear_bit(BLK_MQ_S_INACTIVE
, &hctx
->state
);
3355 * 'cpu' is going away. splice any existing rq_list entries from this
3356 * software queue to the hw queue dispatch list, and ensure that it
3359 static int blk_mq_hctx_notify_dead(unsigned int cpu
, struct hlist_node
*node
)
3361 struct blk_mq_hw_ctx
*hctx
;
3362 struct blk_mq_ctx
*ctx
;
3364 enum hctx_type type
;
3366 hctx
= hlist_entry_safe(node
, struct blk_mq_hw_ctx
, cpuhp_dead
);
3367 if (!cpumask_test_cpu(cpu
, hctx
->cpumask
))
3370 ctx
= __blk_mq_get_ctx(hctx
->queue
, cpu
);
3373 spin_lock(&ctx
->lock
);
3374 if (!list_empty(&ctx
->rq_lists
[type
])) {
3375 list_splice_init(&ctx
->rq_lists
[type
], &tmp
);
3376 blk_mq_hctx_clear_pending(hctx
, ctx
);
3378 spin_unlock(&ctx
->lock
);
3380 if (list_empty(&tmp
))
3383 spin_lock(&hctx
->lock
);
3384 list_splice_tail_init(&tmp
, &hctx
->dispatch
);
3385 spin_unlock(&hctx
->lock
);
3387 blk_mq_run_hw_queue(hctx
, true);
3391 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx
*hctx
)
3393 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
3394 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
3395 &hctx
->cpuhp_online
);
3396 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD
,
3401 * Before freeing hw queue, clearing the flush request reference in
3402 * tags->rqs[] for avoiding potential UAF.
3404 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags
*tags
,
3405 unsigned int queue_depth
, struct request
*flush_rq
)
3408 unsigned long flags
;
3410 /* The hw queue may not be mapped yet */
3414 WARN_ON_ONCE(req_ref_read(flush_rq
) != 0);
3416 for (i
= 0; i
< queue_depth
; i
++)
3417 cmpxchg(&tags
->rqs
[i
], flush_rq
, NULL
);
3420 * Wait until all pending iteration is done.
3422 * Request reference is cleared and it is guaranteed to be observed
3423 * after the ->lock is released.
3425 spin_lock_irqsave(&tags
->lock
, flags
);
3426 spin_unlock_irqrestore(&tags
->lock
, flags
);
3429 /* hctx->ctxs will be freed in queue's release handler */
3430 static void blk_mq_exit_hctx(struct request_queue
*q
,
3431 struct blk_mq_tag_set
*set
,
3432 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
3434 struct request
*flush_rq
= hctx
->fq
->flush_rq
;
3436 if (blk_mq_hw_queue_mapped(hctx
))
3437 blk_mq_tag_idle(hctx
);
3439 if (blk_queue_init_done(q
))
3440 blk_mq_clear_flush_rq_mapping(set
->tags
[hctx_idx
],
3441 set
->queue_depth
, flush_rq
);
3442 if (set
->ops
->exit_request
)
3443 set
->ops
->exit_request(set
, flush_rq
, hctx_idx
);
3445 if (set
->ops
->exit_hctx
)
3446 set
->ops
->exit_hctx(hctx
, hctx_idx
);
3448 blk_mq_remove_cpuhp(hctx
);
3450 xa_erase(&q
->hctx_table
, hctx_idx
);
3452 spin_lock(&q
->unused_hctx_lock
);
3453 list_add(&hctx
->hctx_list
, &q
->unused_hctx_list
);
3454 spin_unlock(&q
->unused_hctx_lock
);
3457 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
3458 struct blk_mq_tag_set
*set
, int nr_queue
)
3460 struct blk_mq_hw_ctx
*hctx
;
3463 queue_for_each_hw_ctx(q
, hctx
, i
) {
3466 blk_mq_exit_hctx(q
, set
, hctx
, i
);
3470 static int blk_mq_init_hctx(struct request_queue
*q
,
3471 struct blk_mq_tag_set
*set
,
3472 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
3474 hctx
->queue_num
= hctx_idx
;
3476 if (!(hctx
->flags
& BLK_MQ_F_STACKING
))
3477 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE
,
3478 &hctx
->cpuhp_online
);
3479 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD
, &hctx
->cpuhp_dead
);
3481 hctx
->tags
= set
->tags
[hctx_idx
];
3483 if (set
->ops
->init_hctx
&&
3484 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
3485 goto unregister_cpu_notifier
;
3487 if (blk_mq_init_request(set
, hctx
->fq
->flush_rq
, hctx_idx
,
3491 if (xa_insert(&q
->hctx_table
, hctx_idx
, hctx
, GFP_KERNEL
))
3497 if (set
->ops
->exit_request
)
3498 set
->ops
->exit_request(set
, hctx
->fq
->flush_rq
, hctx_idx
);
3500 if (set
->ops
->exit_hctx
)
3501 set
->ops
->exit_hctx(hctx
, hctx_idx
);
3502 unregister_cpu_notifier
:
3503 blk_mq_remove_cpuhp(hctx
);
3507 static struct blk_mq_hw_ctx
*
3508 blk_mq_alloc_hctx(struct request_queue
*q
, struct blk_mq_tag_set
*set
,
3511 struct blk_mq_hw_ctx
*hctx
;
3512 gfp_t gfp
= GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
;
3514 hctx
= kzalloc_node(sizeof(struct blk_mq_hw_ctx
), gfp
, node
);
3516 goto fail_alloc_hctx
;
3518 if (!zalloc_cpumask_var_node(&hctx
->cpumask
, gfp
, node
))
3521 atomic_set(&hctx
->nr_active
, 0);
3522 if (node
== NUMA_NO_NODE
)
3523 node
= set
->numa_node
;
3524 hctx
->numa_node
= node
;
3526 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
3527 spin_lock_init(&hctx
->lock
);
3528 INIT_LIST_HEAD(&hctx
->dispatch
);
3530 hctx
->flags
= set
->flags
& ~BLK_MQ_F_TAG_QUEUE_SHARED
;
3532 INIT_LIST_HEAD(&hctx
->hctx_list
);
3535 * Allocate space for all possible cpus to avoid allocation at
3538 hctx
->ctxs
= kmalloc_array_node(nr_cpu_ids
, sizeof(void *),
3543 if (sbitmap_init_node(&hctx
->ctx_map
, nr_cpu_ids
, ilog2(8),
3544 gfp
, node
, false, false))
3548 spin_lock_init(&hctx
->dispatch_wait_lock
);
3549 init_waitqueue_func_entry(&hctx
->dispatch_wait
, blk_mq_dispatch_wake
);
3550 INIT_LIST_HEAD(&hctx
->dispatch_wait
.entry
);
3552 hctx
->fq
= blk_alloc_flush_queue(hctx
->numa_node
, set
->cmd_size
, gfp
);
3556 blk_mq_hctx_kobj_init(hctx
);
3561 sbitmap_free(&hctx
->ctx_map
);
3565 free_cpumask_var(hctx
->cpumask
);
3572 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
3573 unsigned int nr_hw_queues
)
3575 struct blk_mq_tag_set
*set
= q
->tag_set
;
3578 for_each_possible_cpu(i
) {
3579 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
3580 struct blk_mq_hw_ctx
*hctx
;
3584 spin_lock_init(&__ctx
->lock
);
3585 for (k
= HCTX_TYPE_DEFAULT
; k
< HCTX_MAX_TYPES
; k
++)
3586 INIT_LIST_HEAD(&__ctx
->rq_lists
[k
]);
3591 * Set local node, IFF we have more than one hw queue. If
3592 * not, we remain on the home node of the device
3594 for (j
= 0; j
< set
->nr_maps
; j
++) {
3595 hctx
= blk_mq_map_queue_type(q
, j
, i
);
3596 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
3597 hctx
->numa_node
= cpu_to_node(i
);
3602 struct blk_mq_tags
*blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set
*set
,
3603 unsigned int hctx_idx
,
3606 struct blk_mq_tags
*tags
;
3609 tags
= blk_mq_alloc_rq_map(set
, hctx_idx
, depth
, set
->reserved_tags
);
3613 ret
= blk_mq_alloc_rqs(set
, tags
, hctx_idx
, depth
);
3615 blk_mq_free_rq_map(tags
);
3622 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set
*set
,
3625 if (blk_mq_is_shared_tags(set
->flags
)) {
3626 set
->tags
[hctx_idx
] = set
->shared_tags
;
3631 set
->tags
[hctx_idx
] = blk_mq_alloc_map_and_rqs(set
, hctx_idx
,
3634 return set
->tags
[hctx_idx
];
3637 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set
*set
,
3638 struct blk_mq_tags
*tags
,
3639 unsigned int hctx_idx
)
3642 blk_mq_free_rqs(set
, tags
, hctx_idx
);
3643 blk_mq_free_rq_map(tags
);
3647 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set
*set
,
3648 unsigned int hctx_idx
)
3650 if (!blk_mq_is_shared_tags(set
->flags
))
3651 blk_mq_free_map_and_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
);
3653 set
->tags
[hctx_idx
] = NULL
;
3656 static void blk_mq_map_swqueue(struct request_queue
*q
)
3658 unsigned int j
, hctx_idx
;
3660 struct blk_mq_hw_ctx
*hctx
;
3661 struct blk_mq_ctx
*ctx
;
3662 struct blk_mq_tag_set
*set
= q
->tag_set
;
3664 queue_for_each_hw_ctx(q
, hctx
, i
) {
3665 cpumask_clear(hctx
->cpumask
);
3667 hctx
->dispatch_from
= NULL
;
3671 * Map software to hardware queues.
3673 * If the cpu isn't present, the cpu is mapped to first hctx.
3675 for_each_possible_cpu(i
) {
3677 ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
3678 for (j
= 0; j
< set
->nr_maps
; j
++) {
3679 if (!set
->map
[j
].nr_queues
) {
3680 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
3681 HCTX_TYPE_DEFAULT
, i
);
3684 hctx_idx
= set
->map
[j
].mq_map
[i
];
3685 /* unmapped hw queue can be remapped after CPU topo changed */
3686 if (!set
->tags
[hctx_idx
] &&
3687 !__blk_mq_alloc_map_and_rqs(set
, hctx_idx
)) {
3689 * If tags initialization fail for some hctx,
3690 * that hctx won't be brought online. In this
3691 * case, remap the current ctx to hctx[0] which
3692 * is guaranteed to always have tags allocated
3694 set
->map
[j
].mq_map
[i
] = 0;
3697 hctx
= blk_mq_map_queue_type(q
, j
, i
);
3698 ctx
->hctxs
[j
] = hctx
;
3700 * If the CPU is already set in the mask, then we've
3701 * mapped this one already. This can happen if
3702 * devices share queues across queue maps.
3704 if (cpumask_test_cpu(i
, hctx
->cpumask
))
3707 cpumask_set_cpu(i
, hctx
->cpumask
);
3709 ctx
->index_hw
[hctx
->type
] = hctx
->nr_ctx
;
3710 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
3713 * If the nr_ctx type overflows, we have exceeded the
3714 * amount of sw queues we can support.
3716 BUG_ON(!hctx
->nr_ctx
);
3719 for (; j
< HCTX_MAX_TYPES
; j
++)
3720 ctx
->hctxs
[j
] = blk_mq_map_queue_type(q
,
3721 HCTX_TYPE_DEFAULT
, i
);
3724 queue_for_each_hw_ctx(q
, hctx
, i
) {
3726 * If no software queues are mapped to this hardware queue,
3727 * disable it and free the request entries.
3729 if (!hctx
->nr_ctx
) {
3730 /* Never unmap queue 0. We need it as a
3731 * fallback in case of a new remap fails
3735 __blk_mq_free_map_and_rqs(set
, i
);
3741 hctx
->tags
= set
->tags
[i
];
3742 WARN_ON(!hctx
->tags
);
3745 * Set the map size to the number of mapped software queues.
3746 * This is more accurate and more efficient than looping
3747 * over all possibly mapped software queues.
3749 sbitmap_resize(&hctx
->ctx_map
, hctx
->nr_ctx
);
3752 * Initialize batch roundrobin counts
3754 hctx
->next_cpu
= blk_mq_first_mapped_cpu(hctx
);
3755 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
3760 * Caller needs to ensure that we're either frozen/quiesced, or that
3761 * the queue isn't live yet.
3763 static void queue_set_hctx_shared(struct request_queue
*q
, bool shared
)
3765 struct blk_mq_hw_ctx
*hctx
;
3768 queue_for_each_hw_ctx(q
, hctx
, i
) {
3770 hctx
->flags
|= BLK_MQ_F_TAG_QUEUE_SHARED
;
3772 blk_mq_tag_idle(hctx
);
3773 hctx
->flags
&= ~BLK_MQ_F_TAG_QUEUE_SHARED
;
3778 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set
*set
,
3781 struct request_queue
*q
;
3783 lockdep_assert_held(&set
->tag_list_lock
);
3785 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
3786 blk_mq_freeze_queue(q
);
3787 queue_set_hctx_shared(q
, shared
);
3788 blk_mq_unfreeze_queue(q
);
3792 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
3794 struct blk_mq_tag_set
*set
= q
->tag_set
;
3796 mutex_lock(&set
->tag_list_lock
);
3797 list_del(&q
->tag_set_list
);
3798 if (list_is_singular(&set
->tag_list
)) {
3799 /* just transitioned to unshared */
3800 set
->flags
&= ~BLK_MQ_F_TAG_QUEUE_SHARED
;
3801 /* update existing queue */
3802 blk_mq_update_tag_set_shared(set
, false);
3804 mutex_unlock(&set
->tag_list_lock
);
3805 INIT_LIST_HEAD(&q
->tag_set_list
);
3808 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
3809 struct request_queue
*q
)
3811 mutex_lock(&set
->tag_list_lock
);
3814 * Check to see if we're transitioning to shared (from 1 to 2 queues).
3816 if (!list_empty(&set
->tag_list
) &&
3817 !(set
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)) {
3818 set
->flags
|= BLK_MQ_F_TAG_QUEUE_SHARED
;
3819 /* update existing queue */
3820 blk_mq_update_tag_set_shared(set
, true);
3822 if (set
->flags
& BLK_MQ_F_TAG_QUEUE_SHARED
)
3823 queue_set_hctx_shared(q
, true);
3824 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
3826 mutex_unlock(&set
->tag_list_lock
);
3829 /* All allocations will be freed in release handler of q->mq_kobj */
3830 static int blk_mq_alloc_ctxs(struct request_queue
*q
)
3832 struct blk_mq_ctxs
*ctxs
;
3835 ctxs
= kzalloc(sizeof(*ctxs
), GFP_KERNEL
);
3839 ctxs
->queue_ctx
= alloc_percpu(struct blk_mq_ctx
);
3840 if (!ctxs
->queue_ctx
)
3843 for_each_possible_cpu(cpu
) {
3844 struct blk_mq_ctx
*ctx
= per_cpu_ptr(ctxs
->queue_ctx
, cpu
);
3848 q
->mq_kobj
= &ctxs
->kobj
;
3849 q
->queue_ctx
= ctxs
->queue_ctx
;
3858 * It is the actual release handler for mq, but we do it from
3859 * request queue's release handler for avoiding use-after-free
3860 * and headache because q->mq_kobj shouldn't have been introduced,
3861 * but we can't group ctx/kctx kobj without it.
3863 void blk_mq_release(struct request_queue
*q
)
3865 struct blk_mq_hw_ctx
*hctx
, *next
;
3868 queue_for_each_hw_ctx(q
, hctx
, i
)
3869 WARN_ON_ONCE(hctx
&& list_empty(&hctx
->hctx_list
));
3871 /* all hctx are in .unused_hctx_list now */
3872 list_for_each_entry_safe(hctx
, next
, &q
->unused_hctx_list
, hctx_list
) {
3873 list_del_init(&hctx
->hctx_list
);
3874 kobject_put(&hctx
->kobj
);
3877 xa_destroy(&q
->hctx_table
);
3880 * release .mq_kobj and sw queue's kobject now because
3881 * both share lifetime with request queue.
3883 blk_mq_sysfs_deinit(q
);
3886 static struct request_queue
*blk_mq_init_queue_data(struct blk_mq_tag_set
*set
,
3889 struct request_queue
*q
;
3892 q
= blk_alloc_queue(set
->numa_node
, set
->flags
& BLK_MQ_F_BLOCKING
);
3894 return ERR_PTR(-ENOMEM
);
3895 q
->queuedata
= queuedata
;
3896 ret
= blk_mq_init_allocated_queue(set
, q
);
3898 blk_cleanup_queue(q
);
3899 return ERR_PTR(ret
);
3904 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
3906 return blk_mq_init_queue_data(set
, NULL
);
3908 EXPORT_SYMBOL(blk_mq_init_queue
);
3910 struct gendisk
*__blk_mq_alloc_disk(struct blk_mq_tag_set
*set
, void *queuedata
,
3911 struct lock_class_key
*lkclass
)
3913 struct request_queue
*q
;
3914 struct gendisk
*disk
;
3916 q
= blk_mq_init_queue_data(set
, queuedata
);
3920 disk
= __alloc_disk_node(q
, set
->numa_node
, lkclass
);
3922 blk_cleanup_queue(q
);
3923 return ERR_PTR(-ENOMEM
);
3927 EXPORT_SYMBOL(__blk_mq_alloc_disk
);
3929 static struct blk_mq_hw_ctx
*blk_mq_alloc_and_init_hctx(
3930 struct blk_mq_tag_set
*set
, struct request_queue
*q
,
3931 int hctx_idx
, int node
)
3933 struct blk_mq_hw_ctx
*hctx
= NULL
, *tmp
;
3935 /* reuse dead hctx first */
3936 spin_lock(&q
->unused_hctx_lock
);
3937 list_for_each_entry(tmp
, &q
->unused_hctx_list
, hctx_list
) {
3938 if (tmp
->numa_node
== node
) {
3944 list_del_init(&hctx
->hctx_list
);
3945 spin_unlock(&q
->unused_hctx_lock
);
3948 hctx
= blk_mq_alloc_hctx(q
, set
, node
);
3952 if (blk_mq_init_hctx(q
, set
, hctx
, hctx_idx
))
3958 kobject_put(&hctx
->kobj
);
3963 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set
*set
,
3964 struct request_queue
*q
)
3966 struct blk_mq_hw_ctx
*hctx
;
3969 /* protect against switching io scheduler */
3970 mutex_lock(&q
->sysfs_lock
);
3971 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
3973 int node
= blk_mq_get_hctx_node(set
, i
);
3974 struct blk_mq_hw_ctx
*old_hctx
= xa_load(&q
->hctx_table
, i
);
3977 old_node
= old_hctx
->numa_node
;
3978 blk_mq_exit_hctx(q
, set
, old_hctx
, i
);
3981 if (!blk_mq_alloc_and_init_hctx(set
, q
, i
, node
)) {
3984 pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
3986 hctx
= blk_mq_alloc_and_init_hctx(set
, q
, i
, old_node
);
3987 WARN_ON_ONCE(!hctx
);
3991 * Increasing nr_hw_queues fails. Free the newly allocated
3992 * hctxs and keep the previous q->nr_hw_queues.
3994 if (i
!= set
->nr_hw_queues
) {
3995 j
= q
->nr_hw_queues
;
3998 q
->nr_hw_queues
= set
->nr_hw_queues
;
4001 xa_for_each_start(&q
->hctx_table
, j
, hctx
, j
)
4002 blk_mq_exit_hctx(q
, set
, hctx
, j
);
4003 mutex_unlock(&q
->sysfs_lock
);
4006 static void blk_mq_update_poll_flag(struct request_queue
*q
)
4008 struct blk_mq_tag_set
*set
= q
->tag_set
;
4010 if (set
->nr_maps
> HCTX_TYPE_POLL
&&
4011 set
->map
[HCTX_TYPE_POLL
].nr_queues
)
4012 blk_queue_flag_set(QUEUE_FLAG_POLL
, q
);
4014 blk_queue_flag_clear(QUEUE_FLAG_POLL
, q
);
4017 int blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
4018 struct request_queue
*q
)
4020 WARN_ON_ONCE(blk_queue_has_srcu(q
) !=
4021 !!(set
->flags
& BLK_MQ_F_BLOCKING
));
4023 /* mark the queue as mq asap */
4024 q
->mq_ops
= set
->ops
;
4026 q
->poll_cb
= blk_stat_alloc_callback(blk_mq_poll_stats_fn
,
4027 blk_mq_poll_stats_bkt
,
4028 BLK_MQ_POLL_STATS_BKTS
, q
);
4032 if (blk_mq_alloc_ctxs(q
))
4035 /* init q->mq_kobj and sw queues' kobjects */
4036 blk_mq_sysfs_init(q
);
4038 INIT_LIST_HEAD(&q
->unused_hctx_list
);
4039 spin_lock_init(&q
->unused_hctx_lock
);
4041 xa_init(&q
->hctx_table
);
4043 blk_mq_realloc_hw_ctxs(set
, q
);
4044 if (!q
->nr_hw_queues
)
4047 INIT_WORK(&q
->timeout_work
, blk_mq_timeout_work
);
4048 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
4052 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
4053 blk_mq_update_poll_flag(q
);
4055 INIT_DELAYED_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
4056 INIT_LIST_HEAD(&q
->requeue_list
);
4057 spin_lock_init(&q
->requeue_lock
);
4059 q
->nr_requests
= set
->queue_depth
;
4062 * Default to classic polling
4064 q
->poll_nsec
= BLK_MQ_POLL_CLASSIC
;
4066 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
4067 blk_mq_add_queue_tag_set(set
, q
);
4068 blk_mq_map_swqueue(q
);
4072 xa_destroy(&q
->hctx_table
);
4073 q
->nr_hw_queues
= 0;
4074 blk_mq_sysfs_deinit(q
);
4076 blk_stat_free_callback(q
->poll_cb
);
4082 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
4084 /* tags can _not_ be used after returning from blk_mq_exit_queue */
4085 void blk_mq_exit_queue(struct request_queue
*q
)
4087 struct blk_mq_tag_set
*set
= q
->tag_set
;
4089 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
4090 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
4091 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
4092 blk_mq_del_queue_tag_set(q
);
4095 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
4099 if (blk_mq_is_shared_tags(set
->flags
)) {
4100 set
->shared_tags
= blk_mq_alloc_map_and_rqs(set
,
4103 if (!set
->shared_tags
)
4107 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
4108 if (!__blk_mq_alloc_map_and_rqs(set
, i
))
4117 __blk_mq_free_map_and_rqs(set
, i
);
4119 if (blk_mq_is_shared_tags(set
->flags
)) {
4120 blk_mq_free_map_and_rqs(set
, set
->shared_tags
,
4121 BLK_MQ_NO_HCTX_IDX
);
4128 * Allocate the request maps associated with this tag_set. Note that this
4129 * may reduce the depth asked for, if memory is tight. set->queue_depth
4130 * will be updated to reflect the allocated depth.
4132 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set
*set
)
4137 depth
= set
->queue_depth
;
4139 err
= __blk_mq_alloc_rq_maps(set
);
4143 set
->queue_depth
>>= 1;
4144 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
4148 } while (set
->queue_depth
);
4150 if (!set
->queue_depth
|| err
) {
4151 pr_err("blk-mq: failed to allocate request map\n");
4155 if (depth
!= set
->queue_depth
)
4156 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
4157 depth
, set
->queue_depth
);
4162 static int blk_mq_update_queue_map(struct blk_mq_tag_set
*set
)
4165 * blk_mq_map_queues() and multiple .map_queues() implementations
4166 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
4167 * number of hardware queues.
4169 if (set
->nr_maps
== 1)
4170 set
->map
[HCTX_TYPE_DEFAULT
].nr_queues
= set
->nr_hw_queues
;
4172 if (set
->ops
->map_queues
&& !is_kdump_kernel()) {
4176 * transport .map_queues is usually done in the following
4179 * for (queue = 0; queue < set->nr_hw_queues; queue++) {
4180 * mask = get_cpu_mask(queue)
4181 * for_each_cpu(cpu, mask)
4182 * set->map[x].mq_map[cpu] = queue;
4185 * When we need to remap, the table has to be cleared for
4186 * killing stale mapping since one CPU may not be mapped
4189 for (i
= 0; i
< set
->nr_maps
; i
++)
4190 blk_mq_clear_mq_map(&set
->map
[i
]);
4192 return set
->ops
->map_queues(set
);
4194 BUG_ON(set
->nr_maps
> 1);
4195 return blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
4199 static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set
*set
,
4200 int cur_nr_hw_queues
, int new_nr_hw_queues
)
4202 struct blk_mq_tags
**new_tags
;
4204 if (cur_nr_hw_queues
>= new_nr_hw_queues
)
4207 new_tags
= kcalloc_node(new_nr_hw_queues
, sizeof(struct blk_mq_tags
*),
4208 GFP_KERNEL
, set
->numa_node
);
4213 memcpy(new_tags
, set
->tags
, cur_nr_hw_queues
*
4214 sizeof(*set
->tags
));
4216 set
->tags
= new_tags
;
4217 set
->nr_hw_queues
= new_nr_hw_queues
;
4222 static int blk_mq_alloc_tag_set_tags(struct blk_mq_tag_set
*set
,
4223 int new_nr_hw_queues
)
4225 return blk_mq_realloc_tag_set_tags(set
, 0, new_nr_hw_queues
);
4229 * Alloc a tag set to be associated with one or more request queues.
4230 * May fail with EINVAL for various error conditions. May adjust the
4231 * requested depth down, if it's too large. In that case, the set
4232 * value will be stored in set->queue_depth.
4234 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
4238 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
4240 if (!set
->nr_hw_queues
)
4242 if (!set
->queue_depth
)
4244 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
4247 if (!set
->ops
->queue_rq
)
4250 if (!set
->ops
->get_budget
^ !set
->ops
->put_budget
)
4253 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
4254 pr_info("blk-mq: reduced tag depth to %u\n",
4256 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
4261 else if (set
->nr_maps
> HCTX_MAX_TYPES
)
4265 * If a crashdump is active, then we are potentially in a very
4266 * memory constrained environment. Limit us to 1 queue and
4267 * 64 tags to prevent using too much memory.
4269 if (is_kdump_kernel()) {
4270 set
->nr_hw_queues
= 1;
4272 set
->queue_depth
= min(64U, set
->queue_depth
);
4275 * There is no use for more h/w queues than cpus if we just have
4278 if (set
->nr_maps
== 1 && set
->nr_hw_queues
> nr_cpu_ids
)
4279 set
->nr_hw_queues
= nr_cpu_ids
;
4281 if (blk_mq_alloc_tag_set_tags(set
, set
->nr_hw_queues
) < 0)
4285 for (i
= 0; i
< set
->nr_maps
; i
++) {
4286 set
->map
[i
].mq_map
= kcalloc_node(nr_cpu_ids
,
4287 sizeof(set
->map
[i
].mq_map
[0]),
4288 GFP_KERNEL
, set
->numa_node
);
4289 if (!set
->map
[i
].mq_map
)
4290 goto out_free_mq_map
;
4291 set
->map
[i
].nr_queues
= is_kdump_kernel() ? 1 : set
->nr_hw_queues
;
4294 ret
= blk_mq_update_queue_map(set
);
4296 goto out_free_mq_map
;
4298 ret
= blk_mq_alloc_set_map_and_rqs(set
);
4300 goto out_free_mq_map
;
4302 mutex_init(&set
->tag_list_lock
);
4303 INIT_LIST_HEAD(&set
->tag_list
);
4308 for (i
= 0; i
< set
->nr_maps
; i
++) {
4309 kfree(set
->map
[i
].mq_map
);
4310 set
->map
[i
].mq_map
= NULL
;
4316 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
4318 /* allocate and initialize a tagset for a simple single-queue device */
4319 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set
*set
,
4320 const struct blk_mq_ops
*ops
, unsigned int queue_depth
,
4321 unsigned int set_flags
)
4323 memset(set
, 0, sizeof(*set
));
4325 set
->nr_hw_queues
= 1;
4327 set
->queue_depth
= queue_depth
;
4328 set
->numa_node
= NUMA_NO_NODE
;
4329 set
->flags
= set_flags
;
4330 return blk_mq_alloc_tag_set(set
);
4332 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set
);
4334 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
4338 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
4339 __blk_mq_free_map_and_rqs(set
, i
);
4341 if (blk_mq_is_shared_tags(set
->flags
)) {
4342 blk_mq_free_map_and_rqs(set
, set
->shared_tags
,
4343 BLK_MQ_NO_HCTX_IDX
);
4346 for (j
= 0; j
< set
->nr_maps
; j
++) {
4347 kfree(set
->map
[j
].mq_map
);
4348 set
->map
[j
].mq_map
= NULL
;
4354 EXPORT_SYMBOL(blk_mq_free_tag_set
);
4356 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
4358 struct blk_mq_tag_set
*set
= q
->tag_set
;
4359 struct blk_mq_hw_ctx
*hctx
;
4366 if (q
->nr_requests
== nr
)
4369 blk_mq_freeze_queue(q
);
4370 blk_mq_quiesce_queue(q
);
4373 queue_for_each_hw_ctx(q
, hctx
, i
) {
4377 * If we're using an MQ scheduler, just update the scheduler
4378 * queue depth. This is similar to what the old code would do.
4380 if (hctx
->sched_tags
) {
4381 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->sched_tags
,
4384 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->tags
, nr
,
4389 if (q
->elevator
&& q
->elevator
->type
->ops
.depth_updated
)
4390 q
->elevator
->type
->ops
.depth_updated(hctx
);
4393 q
->nr_requests
= nr
;
4394 if (blk_mq_is_shared_tags(set
->flags
)) {
4396 blk_mq_tag_update_sched_shared_tags(q
);
4398 blk_mq_tag_resize_shared_tags(set
, nr
);
4402 blk_mq_unquiesce_queue(q
);
4403 blk_mq_unfreeze_queue(q
);
4409 * request_queue and elevator_type pair.
4410 * It is just used by __blk_mq_update_nr_hw_queues to cache
4411 * the elevator_type associated with a request_queue.
4413 struct blk_mq_qe_pair
{
4414 struct list_head node
;
4415 struct request_queue
*q
;
4416 struct elevator_type
*type
;
4420 * Cache the elevator_type in qe pair list and switch the
4421 * io scheduler to 'none'
4423 static bool blk_mq_elv_switch_none(struct list_head
*head
,
4424 struct request_queue
*q
)
4426 struct blk_mq_qe_pair
*qe
;
4431 qe
= kmalloc(sizeof(*qe
), GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
);
4435 /* q->elevator needs protection from ->sysfs_lock */
4436 mutex_lock(&q
->sysfs_lock
);
4438 INIT_LIST_HEAD(&qe
->node
);
4440 qe
->type
= q
->elevator
->type
;
4441 list_add(&qe
->node
, head
);
4444 * After elevator_switch_mq, the previous elevator_queue will be
4445 * released by elevator_release. The reference of the io scheduler
4446 * module get by elevator_get will also be put. So we need to get
4447 * a reference of the io scheduler module here to prevent it to be
4450 __module_get(qe
->type
->elevator_owner
);
4451 elevator_switch_mq(q
, NULL
);
4452 mutex_unlock(&q
->sysfs_lock
);
4457 static struct blk_mq_qe_pair
*blk_lookup_qe_pair(struct list_head
*head
,
4458 struct request_queue
*q
)
4460 struct blk_mq_qe_pair
*qe
;
4462 list_for_each_entry(qe
, head
, node
)
4469 static void blk_mq_elv_switch_back(struct list_head
*head
,
4470 struct request_queue
*q
)
4472 struct blk_mq_qe_pair
*qe
;
4473 struct elevator_type
*t
;
4475 qe
= blk_lookup_qe_pair(head
, q
);
4479 list_del(&qe
->node
);
4482 mutex_lock(&q
->sysfs_lock
);
4483 elevator_switch_mq(q
, t
);
4484 mutex_unlock(&q
->sysfs_lock
);
4487 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
,
4490 struct request_queue
*q
;
4492 int prev_nr_hw_queues
;
4494 lockdep_assert_held(&set
->tag_list_lock
);
4496 if (set
->nr_maps
== 1 && nr_hw_queues
> nr_cpu_ids
)
4497 nr_hw_queues
= nr_cpu_ids
;
4498 if (nr_hw_queues
< 1)
4500 if (set
->nr_maps
== 1 && nr_hw_queues
== set
->nr_hw_queues
)
4503 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4504 blk_mq_freeze_queue(q
);
4506 * Switch IO scheduler to 'none', cleaning up the data associated
4507 * with the previous scheduler. We will switch back once we are done
4508 * updating the new sw to hw queue mappings.
4510 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4511 if (!blk_mq_elv_switch_none(&head
, q
))
4514 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
4515 blk_mq_debugfs_unregister_hctxs(q
);
4516 blk_mq_sysfs_unregister(q
);
4519 prev_nr_hw_queues
= set
->nr_hw_queues
;
4520 if (blk_mq_realloc_tag_set_tags(set
, set
->nr_hw_queues
, nr_hw_queues
) <
4524 set
->nr_hw_queues
= nr_hw_queues
;
4526 blk_mq_update_queue_map(set
);
4527 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
4528 blk_mq_realloc_hw_ctxs(set
, q
);
4529 blk_mq_update_poll_flag(q
);
4530 if (q
->nr_hw_queues
!= set
->nr_hw_queues
) {
4531 int i
= prev_nr_hw_queues
;
4533 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4534 nr_hw_queues
, prev_nr_hw_queues
);
4535 for (; i
< set
->nr_hw_queues
; i
++)
4536 __blk_mq_free_map_and_rqs(set
, i
);
4538 set
->nr_hw_queues
= prev_nr_hw_queues
;
4539 blk_mq_map_queues(&set
->map
[HCTX_TYPE_DEFAULT
]);
4542 blk_mq_map_swqueue(q
);
4546 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
4547 blk_mq_sysfs_register(q
);
4548 blk_mq_debugfs_register_hctxs(q
);
4552 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4553 blk_mq_elv_switch_back(&head
, q
);
4555 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
4556 blk_mq_unfreeze_queue(q
);
4559 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
, int nr_hw_queues
)
4561 mutex_lock(&set
->tag_list_lock
);
4562 __blk_mq_update_nr_hw_queues(set
, nr_hw_queues
);
4563 mutex_unlock(&set
->tag_list_lock
);
4565 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues
);
4567 /* Enable polling stats and return whether they were already enabled. */
4568 static bool blk_poll_stats_enable(struct request_queue
*q
)
4573 return blk_stats_alloc_enable(q
);
4576 static void blk_mq_poll_stats_start(struct request_queue
*q
)
4579 * We don't arm the callback if polling stats are not enabled or the
4580 * callback is already active.
4582 if (!q
->poll_stat
|| blk_stat_is_active(q
->poll_cb
))
4585 blk_stat_activate_msecs(q
->poll_cb
, 100);
4588 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
)
4590 struct request_queue
*q
= cb
->data
;
4593 for (bucket
= 0; bucket
< BLK_MQ_POLL_STATS_BKTS
; bucket
++) {
4594 if (cb
->stat
[bucket
].nr_samples
)
4595 q
->poll_stat
[bucket
] = cb
->stat
[bucket
];
4599 static unsigned long blk_mq_poll_nsecs(struct request_queue
*q
,
4602 unsigned long ret
= 0;
4606 * If stats collection isn't on, don't sleep but turn it on for
4609 if (!blk_poll_stats_enable(q
))
4613 * As an optimistic guess, use half of the mean service time
4614 * for this type of request. We can (and should) make this smarter.
4615 * For instance, if the completion latencies are tight, we can
4616 * get closer than just half the mean. This is especially
4617 * important on devices where the completion latencies are longer
4618 * than ~10 usec. We do use the stats for the relevant IO size
4619 * if available which does lead to better estimates.
4621 bucket
= blk_mq_poll_stats_bkt(rq
);
4625 if (q
->poll_stat
[bucket
].nr_samples
)
4626 ret
= (q
->poll_stat
[bucket
].mean
+ 1) / 2;
4631 static bool blk_mq_poll_hybrid(struct request_queue
*q
, blk_qc_t qc
)
4633 struct blk_mq_hw_ctx
*hctx
= blk_qc_to_hctx(q
, qc
);
4634 struct request
*rq
= blk_qc_to_rq(hctx
, qc
);
4635 struct hrtimer_sleeper hs
;
4636 enum hrtimer_mode mode
;
4641 * If a request has completed on queue that uses an I/O scheduler, we
4642 * won't get back a request from blk_qc_to_rq.
4644 if (!rq
|| (rq
->rq_flags
& RQF_MQ_POLL_SLEPT
))
4648 * If we get here, hybrid polling is enabled. Hence poll_nsec can be:
4650 * 0: use half of prev avg
4651 * >0: use this specific value
4653 if (q
->poll_nsec
> 0)
4654 nsecs
= q
->poll_nsec
;
4656 nsecs
= blk_mq_poll_nsecs(q
, rq
);
4661 rq
->rq_flags
|= RQF_MQ_POLL_SLEPT
;
4664 * This will be replaced with the stats tracking code, using
4665 * 'avg_completion_time / 2' as the pre-sleep target.
4669 mode
= HRTIMER_MODE_REL
;
4670 hrtimer_init_sleeper_on_stack(&hs
, CLOCK_MONOTONIC
, mode
);
4671 hrtimer_set_expires(&hs
.timer
, kt
);
4674 if (blk_mq_rq_state(rq
) == MQ_RQ_COMPLETE
)
4676 set_current_state(TASK_UNINTERRUPTIBLE
);
4677 hrtimer_sleeper_start_expires(&hs
, mode
);
4680 hrtimer_cancel(&hs
.timer
);
4681 mode
= HRTIMER_MODE_ABS
;
4682 } while (hs
.task
&& !signal_pending(current
));
4684 __set_current_state(TASK_RUNNING
);
4685 destroy_hrtimer_on_stack(&hs
.timer
);
4688 * If we sleep, have the caller restart the poll loop to reset the
4689 * state. Like for the other success return cases, the caller is
4690 * responsible for checking if the IO completed. If the IO isn't
4691 * complete, we'll get called again and will go straight to the busy
4697 static int blk_mq_poll_classic(struct request_queue
*q
, blk_qc_t cookie
,
4698 struct io_comp_batch
*iob
, unsigned int flags
)
4700 struct blk_mq_hw_ctx
*hctx
= blk_qc_to_hctx(q
, cookie
);
4701 long state
= get_current_state();
4705 ret
= q
->mq_ops
->poll(hctx
, iob
);
4707 __set_current_state(TASK_RUNNING
);
4711 if (signal_pending_state(state
, current
))
4712 __set_current_state(TASK_RUNNING
);
4713 if (task_is_running(current
))
4716 if (ret
< 0 || (flags
& BLK_POLL_ONESHOT
))
4719 } while (!need_resched());
4721 __set_current_state(TASK_RUNNING
);
4725 int blk_mq_poll(struct request_queue
*q
, blk_qc_t cookie
, struct io_comp_batch
*iob
,
4728 if (!(flags
& BLK_POLL_NOSLEEP
) &&
4729 q
->poll_nsec
!= BLK_MQ_POLL_CLASSIC
) {
4730 if (blk_mq_poll_hybrid(q
, cookie
))
4733 return blk_mq_poll_classic(q
, cookie
, iob
, flags
);
4736 unsigned int blk_mq_rq_cpu(struct request
*rq
)
4738 return rq
->mq_ctx
->cpu
;
4740 EXPORT_SYMBOL(blk_mq_rq_cpu
);
4742 void blk_mq_cancel_work_sync(struct request_queue
*q
)
4744 if (queue_is_mq(q
)) {
4745 struct blk_mq_hw_ctx
*hctx
;
4748 cancel_delayed_work_sync(&q
->requeue_work
);
4750 queue_for_each_hw_ctx(q
, hctx
, i
)
4751 cancel_delayed_work_sync(&hctx
->run_work
);
4755 static int __init
blk_mq_init(void)
4759 for_each_possible_cpu(i
)
4760 init_llist_head(&per_cpu(blk_cpu_done
, i
));
4761 open_softirq(BLOCK_SOFTIRQ
, blk_done_softirq
);
4763 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD
,
4764 "block/softirq:dead", NULL
,
4765 blk_softirq_cpu_dead
);
4766 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD
, "block/mq:dead", NULL
,
4767 blk_mq_hctx_notify_dead
);
4768 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE
, "block/mq:online",
4769 blk_mq_hctx_notify_online
,
4770 blk_mq_hctx_notify_offline
);
4773 subsys_initcall(blk_mq_init
);