2 * Block multiqueue core code
4 * Copyright (C) 2013-2014 Jens Axboe
5 * Copyright (C) 2013-2014 Christoph Hellwig
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/backing-dev.h>
10 #include <linux/bio.h>
11 #include <linux/blkdev.h>
12 #include <linux/kmemleak.h>
14 #include <linux/init.h>
15 #include <linux/slab.h>
16 #include <linux/workqueue.h>
17 #include <linux/smp.h>
18 #include <linux/llist.h>
19 #include <linux/list_sort.h>
20 #include <linux/cpu.h>
21 #include <linux/cache.h>
22 #include <linux/sched/sysctl.h>
23 #include <linux/sched/topology.h>
24 #include <linux/sched/signal.h>
25 #include <linux/delay.h>
26 #include <linux/crash_dump.h>
27 #include <linux/prefetch.h>
29 #include <trace/events/block.h>
31 #include <linux/blk-mq.h>
34 #include "blk-mq-debugfs.h"
35 #include "blk-mq-tag.h"
38 #include "blk-mq-sched.h"
40 static void blk_mq_poll_stats_start(struct request_queue
*q
);
41 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
);
43 static int blk_mq_poll_stats_bkt(const struct request
*rq
)
45 int ddir
, bytes
, bucket
;
47 ddir
= rq_data_dir(rq
);
48 bytes
= blk_rq_bytes(rq
);
50 bucket
= ddir
+ 2*(ilog2(bytes
) - 9);
54 else if (bucket
>= BLK_MQ_POLL_STATS_BKTS
)
55 return ddir
+ BLK_MQ_POLL_STATS_BKTS
- 2;
61 * Check if any of the ctx's have pending work in this hardware queue
63 bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
65 return sbitmap_any_bit_set(&hctx
->ctx_map
) ||
66 !list_empty_careful(&hctx
->dispatch
) ||
67 blk_mq_sched_has_work(hctx
);
71 * Mark this ctx as having pending work in this hardware queue
73 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
74 struct blk_mq_ctx
*ctx
)
76 if (!sbitmap_test_bit(&hctx
->ctx_map
, ctx
->index_hw
))
77 sbitmap_set_bit(&hctx
->ctx_map
, ctx
->index_hw
);
80 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
81 struct blk_mq_ctx
*ctx
)
83 sbitmap_clear_bit(&hctx
->ctx_map
, ctx
->index_hw
);
86 void blk_freeze_queue_start(struct request_queue
*q
)
90 freeze_depth
= atomic_inc_return(&q
->mq_freeze_depth
);
91 if (freeze_depth
== 1) {
92 percpu_ref_kill(&q
->q_usage_counter
);
93 blk_mq_run_hw_queues(q
, false);
96 EXPORT_SYMBOL_GPL(blk_freeze_queue_start
);
98 void blk_mq_freeze_queue_wait(struct request_queue
*q
)
100 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->q_usage_counter
));
102 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait
);
104 int blk_mq_freeze_queue_wait_timeout(struct request_queue
*q
,
105 unsigned long timeout
)
107 return wait_event_timeout(q
->mq_freeze_wq
,
108 percpu_ref_is_zero(&q
->q_usage_counter
),
111 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout
);
114 * Guarantee no request is in use, so we can change any data structure of
115 * the queue afterward.
117 void blk_freeze_queue(struct request_queue
*q
)
120 * In the !blk_mq case we are only calling this to kill the
121 * q_usage_counter, otherwise this increases the freeze depth
122 * and waits for it to return to zero. For this reason there is
123 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
124 * exported to drivers as the only user for unfreeze is blk_mq.
126 blk_freeze_queue_start(q
);
127 blk_mq_freeze_queue_wait(q
);
130 void blk_mq_freeze_queue(struct request_queue
*q
)
133 * ...just an alias to keep freeze and unfreeze actions balanced
134 * in the blk_mq_* namespace
138 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
140 void blk_mq_unfreeze_queue(struct request_queue
*q
)
144 freeze_depth
= atomic_dec_return(&q
->mq_freeze_depth
);
145 WARN_ON_ONCE(freeze_depth
< 0);
147 percpu_ref_reinit(&q
->q_usage_counter
);
148 wake_up_all(&q
->mq_freeze_wq
);
151 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
154 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
155 * mpt3sas driver such that this function can be removed.
157 void blk_mq_quiesce_queue_nowait(struct request_queue
*q
)
161 spin_lock_irqsave(q
->queue_lock
, flags
);
162 queue_flag_set(QUEUE_FLAG_QUIESCED
, q
);
163 spin_unlock_irqrestore(q
->queue_lock
, flags
);
165 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait
);
168 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
171 * Note: this function does not prevent that the struct request end_io()
172 * callback function is invoked. Once this function is returned, we make
173 * sure no dispatch can happen until the queue is unquiesced via
174 * blk_mq_unquiesce_queue().
176 void blk_mq_quiesce_queue(struct request_queue
*q
)
178 struct blk_mq_hw_ctx
*hctx
;
182 blk_mq_quiesce_queue_nowait(q
);
184 queue_for_each_hw_ctx(q
, hctx
, i
) {
185 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
186 synchronize_srcu(hctx
->queue_rq_srcu
);
193 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue
);
196 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
199 * This function recovers queue into the state before quiescing
200 * which is done by blk_mq_quiesce_queue.
202 void blk_mq_unquiesce_queue(struct request_queue
*q
)
206 spin_lock_irqsave(q
->queue_lock
, flags
);
207 queue_flag_clear(QUEUE_FLAG_QUIESCED
, q
);
208 spin_unlock_irqrestore(q
->queue_lock
, flags
);
210 /* dispatch requests which are inserted during quiescing */
211 blk_mq_run_hw_queues(q
, true);
213 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue
);
215 void blk_mq_wake_waiters(struct request_queue
*q
)
217 struct blk_mq_hw_ctx
*hctx
;
220 queue_for_each_hw_ctx(q
, hctx
, i
)
221 if (blk_mq_hw_queue_mapped(hctx
))
222 blk_mq_tag_wakeup_all(hctx
->tags
, true);
225 * If we are called because the queue has now been marked as
226 * dying, we need to ensure that processes currently waiting on
227 * the queue are notified as well.
229 wake_up_all(&q
->mq_freeze_wq
);
232 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
234 return blk_mq_has_free_tags(hctx
->tags
);
236 EXPORT_SYMBOL(blk_mq_can_queue
);
238 static struct request
*blk_mq_rq_ctx_init(struct blk_mq_alloc_data
*data
,
239 unsigned int tag
, unsigned int op
)
241 struct blk_mq_tags
*tags
= blk_mq_tags_from_data(data
);
242 struct request
*rq
= tags
->static_rqs
[tag
];
246 if (data
->flags
& BLK_MQ_REQ_INTERNAL
) {
248 rq
->internal_tag
= tag
;
250 if (blk_mq_tag_busy(data
->hctx
)) {
251 rq
->rq_flags
= RQF_MQ_INFLIGHT
;
252 atomic_inc(&data
->hctx
->nr_active
);
255 rq
->internal_tag
= -1;
256 data
->hctx
->tags
->rqs
[rq
->tag
] = rq
;
259 INIT_LIST_HEAD(&rq
->queuelist
);
260 /* csd/requeue_work/fifo_time is initialized before use */
262 rq
->mq_ctx
= data
->ctx
;
264 if (blk_queue_io_stat(data
->q
))
265 rq
->rq_flags
|= RQF_IO_STAT
;
266 /* do not touch atomic flags, it needs atomic ops against the timer */
268 INIT_HLIST_NODE(&rq
->hash
);
269 RB_CLEAR_NODE(&rq
->rb_node
);
272 rq
->start_time
= jiffies
;
273 #ifdef CONFIG_BLK_CGROUP
275 set_start_time_ns(rq
);
276 rq
->io_start_time_ns
= 0;
278 rq
->nr_phys_segments
= 0;
279 #if defined(CONFIG_BLK_DEV_INTEGRITY)
280 rq
->nr_integrity_segments
= 0;
283 /* tag was already set */
286 INIT_LIST_HEAD(&rq
->timeout_list
);
290 rq
->end_io_data
= NULL
;
293 data
->ctx
->rq_dispatched
[op_is_sync(op
)]++;
297 static struct request
*blk_mq_get_request(struct request_queue
*q
,
298 struct bio
*bio
, unsigned int op
,
299 struct blk_mq_alloc_data
*data
)
301 struct elevator_queue
*e
= q
->elevator
;
304 struct blk_mq_ctx
*local_ctx
= NULL
;
306 blk_queue_enter_live(q
);
308 if (likely(!data
->ctx
))
309 data
->ctx
= local_ctx
= blk_mq_get_ctx(q
);
310 if (likely(!data
->hctx
))
311 data
->hctx
= blk_mq_map_queue(q
, data
->ctx
->cpu
);
313 data
->flags
|= BLK_MQ_REQ_NOWAIT
;
316 data
->flags
|= BLK_MQ_REQ_INTERNAL
;
319 * Flush requests are special and go directly to the
322 if (!op_is_flush(op
) && e
->type
->ops
.mq
.limit_depth
)
323 e
->type
->ops
.mq
.limit_depth(op
, data
);
326 tag
= blk_mq_get_tag(data
);
327 if (tag
== BLK_MQ_TAG_FAIL
) {
329 blk_mq_put_ctx(local_ctx
);
336 rq
= blk_mq_rq_ctx_init(data
, tag
, op
);
337 if (!op_is_flush(op
)) {
339 if (e
&& e
->type
->ops
.mq
.prepare_request
) {
340 if (e
->type
->icq_cache
&& rq_ioc(bio
))
341 blk_mq_sched_assign_ioc(rq
, bio
);
343 e
->type
->ops
.mq
.prepare_request(rq
, bio
);
344 rq
->rq_flags
|= RQF_ELVPRIV
;
347 data
->hctx
->queued
++;
351 struct request
*blk_mq_alloc_request(struct request_queue
*q
, unsigned int op
,
354 struct blk_mq_alloc_data alloc_data
= { .flags
= flags
};
358 ret
= blk_queue_enter(q
, flags
& BLK_MQ_REQ_NOWAIT
);
362 rq
= blk_mq_get_request(q
, NULL
, op
, &alloc_data
);
365 return ERR_PTR(-EWOULDBLOCK
);
367 blk_mq_put_ctx(alloc_data
.ctx
);
371 rq
->__sector
= (sector_t
) -1;
372 rq
->bio
= rq
->biotail
= NULL
;
375 EXPORT_SYMBOL(blk_mq_alloc_request
);
377 struct request
*blk_mq_alloc_request_hctx(struct request_queue
*q
,
378 unsigned int op
, unsigned int flags
, unsigned int hctx_idx
)
380 struct blk_mq_alloc_data alloc_data
= { .flags
= flags
};
386 * If the tag allocator sleeps we could get an allocation for a
387 * different hardware context. No need to complicate the low level
388 * allocator for this for the rare use case of a command tied to
391 if (WARN_ON_ONCE(!(flags
& BLK_MQ_REQ_NOWAIT
)))
392 return ERR_PTR(-EINVAL
);
394 if (hctx_idx
>= q
->nr_hw_queues
)
395 return ERR_PTR(-EIO
);
397 ret
= blk_queue_enter(q
, true);
402 * Check if the hardware context is actually mapped to anything.
403 * If not tell the caller that it should skip this queue.
405 alloc_data
.hctx
= q
->queue_hw_ctx
[hctx_idx
];
406 if (!blk_mq_hw_queue_mapped(alloc_data
.hctx
)) {
408 return ERR_PTR(-EXDEV
);
410 cpu
= cpumask_first(alloc_data
.hctx
->cpumask
);
411 alloc_data
.ctx
= __blk_mq_get_ctx(q
, cpu
);
413 rq
= blk_mq_get_request(q
, NULL
, op
, &alloc_data
);
416 return ERR_PTR(-EWOULDBLOCK
);
422 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx
);
424 void blk_mq_free_request(struct request
*rq
)
426 struct request_queue
*q
= rq
->q
;
427 struct elevator_queue
*e
= q
->elevator
;
428 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
429 struct blk_mq_hw_ctx
*hctx
= blk_mq_map_queue(q
, ctx
->cpu
);
430 const int sched_tag
= rq
->internal_tag
;
432 if (rq
->rq_flags
& RQF_ELVPRIV
) {
433 if (e
&& e
->type
->ops
.mq
.finish_request
)
434 e
->type
->ops
.mq
.finish_request(rq
);
436 put_io_context(rq
->elv
.icq
->ioc
);
441 ctx
->rq_completed
[rq_is_sync(rq
)]++;
442 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
)
443 atomic_dec(&hctx
->nr_active
);
445 wbt_done(q
->rq_wb
, &rq
->issue_stat
);
447 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
448 clear_bit(REQ_ATOM_POLL_SLEPT
, &rq
->atomic_flags
);
450 blk_mq_put_tag(hctx
, hctx
->tags
, ctx
, rq
->tag
);
452 blk_mq_put_tag(hctx
, hctx
->sched_tags
, ctx
, sched_tag
);
453 blk_mq_sched_restart(hctx
);
456 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
458 inline void __blk_mq_end_request(struct request
*rq
, blk_status_t error
)
460 blk_account_io_done(rq
);
463 wbt_done(rq
->q
->rq_wb
, &rq
->issue_stat
);
464 rq
->end_io(rq
, error
);
466 if (unlikely(blk_bidi_rq(rq
)))
467 blk_mq_free_request(rq
->next_rq
);
468 blk_mq_free_request(rq
);
471 EXPORT_SYMBOL(__blk_mq_end_request
);
473 void blk_mq_end_request(struct request
*rq
, blk_status_t error
)
475 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
477 __blk_mq_end_request(rq
, error
);
479 EXPORT_SYMBOL(blk_mq_end_request
);
481 static void __blk_mq_complete_request_remote(void *data
)
483 struct request
*rq
= data
;
485 rq
->q
->softirq_done_fn(rq
);
488 static void __blk_mq_complete_request(struct request
*rq
)
490 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
494 if (rq
->internal_tag
!= -1)
495 blk_mq_sched_completed_request(rq
);
496 if (rq
->rq_flags
& RQF_STATS
) {
497 blk_mq_poll_stats_start(rq
->q
);
501 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
502 rq
->q
->softirq_done_fn(rq
);
507 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
508 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
510 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
511 rq
->csd
.func
= __blk_mq_complete_request_remote
;
514 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
516 rq
->q
->softirq_done_fn(rq
);
522 * blk_mq_complete_request - end I/O on a request
523 * @rq: the request being processed
526 * Ends all I/O on a request. It does not handle partial completions.
527 * The actual completion happens out-of-order, through a IPI handler.
529 void blk_mq_complete_request(struct request
*rq
)
531 struct request_queue
*q
= rq
->q
;
533 if (unlikely(blk_should_fake_timeout(q
)))
535 if (!blk_mark_rq_complete(rq
))
536 __blk_mq_complete_request(rq
);
538 EXPORT_SYMBOL(blk_mq_complete_request
);
540 int blk_mq_request_started(struct request
*rq
)
542 return test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
544 EXPORT_SYMBOL_GPL(blk_mq_request_started
);
546 void blk_mq_start_request(struct request
*rq
)
548 struct request_queue
*q
= rq
->q
;
550 blk_mq_sched_started_request(rq
);
552 trace_block_rq_issue(q
, rq
);
554 if (test_bit(QUEUE_FLAG_STATS
, &q
->queue_flags
)) {
555 blk_stat_set_issue(&rq
->issue_stat
, blk_rq_sectors(rq
));
556 rq
->rq_flags
|= RQF_STATS
;
557 wbt_issue(q
->rq_wb
, &rq
->issue_stat
);
563 * Ensure that ->deadline is visible before set the started
564 * flag and clear the completed flag.
566 smp_mb__before_atomic();
569 * Mark us as started and clear complete. Complete might have been
570 * set if requeue raced with timeout, which then marked it as
571 * complete. So be sure to clear complete again when we start
572 * the request, otherwise we'll ignore the completion event.
574 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
575 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
576 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
577 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
579 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
581 * Make sure space for the drain appears. We know we can do
582 * this because max_hw_segments has been adjusted to be one
583 * fewer than the device can handle.
585 rq
->nr_phys_segments
++;
588 EXPORT_SYMBOL(blk_mq_start_request
);
591 * When we reach here because queue is busy, REQ_ATOM_COMPLETE
592 * flag isn't set yet, so there may be race with timeout handler,
593 * but given rq->deadline is just set in .queue_rq() under
594 * this situation, the race won't be possible in reality because
595 * rq->timeout should be set as big enough to cover the window
596 * between blk_mq_start_request() called from .queue_rq() and
597 * clearing REQ_ATOM_STARTED here.
599 static void __blk_mq_requeue_request(struct request
*rq
)
601 struct request_queue
*q
= rq
->q
;
603 trace_block_rq_requeue(q
, rq
);
604 wbt_requeue(q
->rq_wb
, &rq
->issue_stat
);
605 blk_mq_sched_requeue_request(rq
);
607 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
608 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
609 rq
->nr_phys_segments
--;
613 void blk_mq_requeue_request(struct request
*rq
, bool kick_requeue_list
)
615 __blk_mq_requeue_request(rq
);
617 BUG_ON(blk_queued_rq(rq
));
618 blk_mq_add_to_requeue_list(rq
, true, kick_requeue_list
);
620 EXPORT_SYMBOL(blk_mq_requeue_request
);
622 static void blk_mq_requeue_work(struct work_struct
*work
)
624 struct request_queue
*q
=
625 container_of(work
, struct request_queue
, requeue_work
.work
);
627 struct request
*rq
, *next
;
630 spin_lock_irqsave(&q
->requeue_lock
, flags
);
631 list_splice_init(&q
->requeue_list
, &rq_list
);
632 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
634 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
635 if (!(rq
->rq_flags
& RQF_SOFTBARRIER
))
638 rq
->rq_flags
&= ~RQF_SOFTBARRIER
;
639 list_del_init(&rq
->queuelist
);
640 blk_mq_sched_insert_request(rq
, true, false, false, true);
643 while (!list_empty(&rq_list
)) {
644 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
645 list_del_init(&rq
->queuelist
);
646 blk_mq_sched_insert_request(rq
, false, false, false, true);
649 blk_mq_run_hw_queues(q
, false);
652 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
,
653 bool kick_requeue_list
)
655 struct request_queue
*q
= rq
->q
;
659 * We abuse this flag that is otherwise used by the I/O scheduler to
660 * request head insertation from the workqueue.
662 BUG_ON(rq
->rq_flags
& RQF_SOFTBARRIER
);
664 spin_lock_irqsave(&q
->requeue_lock
, flags
);
666 rq
->rq_flags
|= RQF_SOFTBARRIER
;
667 list_add(&rq
->queuelist
, &q
->requeue_list
);
669 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
671 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
673 if (kick_requeue_list
)
674 blk_mq_kick_requeue_list(q
);
676 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
678 void blk_mq_kick_requeue_list(struct request_queue
*q
)
680 kblockd_schedule_delayed_work(&q
->requeue_work
, 0);
682 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
684 void blk_mq_delay_kick_requeue_list(struct request_queue
*q
,
687 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND
, &q
->requeue_work
,
688 msecs_to_jiffies(msecs
));
690 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list
);
692 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
694 if (tag
< tags
->nr_tags
) {
695 prefetch(tags
->rqs
[tag
]);
696 return tags
->rqs
[tag
];
701 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
703 struct blk_mq_timeout_data
{
705 unsigned int next_set
;
708 void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
710 const struct blk_mq_ops
*ops
= req
->q
->mq_ops
;
711 enum blk_eh_timer_return ret
= BLK_EH_RESET_TIMER
;
714 * We know that complete is set at this point. If STARTED isn't set
715 * anymore, then the request isn't active and the "timeout" should
716 * just be ignored. This can happen due to the bitflag ordering.
717 * Timeout first checks if STARTED is set, and if it is, assumes
718 * the request is active. But if we race with completion, then
719 * both flags will get cleared. So check here again, and ignore
720 * a timeout event with a request that isn't active.
722 if (!test_bit(REQ_ATOM_STARTED
, &req
->atomic_flags
))
726 ret
= ops
->timeout(req
, reserved
);
730 __blk_mq_complete_request(req
);
732 case BLK_EH_RESET_TIMER
:
734 blk_clear_rq_complete(req
);
736 case BLK_EH_NOT_HANDLED
:
739 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
744 static void blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
745 struct request
*rq
, void *priv
, bool reserved
)
747 struct blk_mq_timeout_data
*data
= priv
;
749 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
753 * The rq being checked may have been freed and reallocated
754 * out already here, we avoid this race by checking rq->deadline
755 * and REQ_ATOM_COMPLETE flag together:
757 * - if rq->deadline is observed as new value because of
758 * reusing, the rq won't be timed out because of timing.
759 * - if rq->deadline is observed as previous value,
760 * REQ_ATOM_COMPLETE flag won't be cleared in reuse path
761 * because we put a barrier between setting rq->deadline
762 * and clearing the flag in blk_mq_start_request(), so
763 * this rq won't be timed out too.
765 if (time_after_eq(jiffies
, rq
->deadline
)) {
766 if (!blk_mark_rq_complete(rq
))
767 blk_mq_rq_timed_out(rq
, reserved
);
768 } else if (!data
->next_set
|| time_after(data
->next
, rq
->deadline
)) {
769 data
->next
= rq
->deadline
;
774 static void blk_mq_timeout_work(struct work_struct
*work
)
776 struct request_queue
*q
=
777 container_of(work
, struct request_queue
, timeout_work
);
778 struct blk_mq_timeout_data data
= {
784 /* A deadlock might occur if a request is stuck requiring a
785 * timeout at the same time a queue freeze is waiting
786 * completion, since the timeout code would not be able to
787 * acquire the queue reference here.
789 * That's why we don't use blk_queue_enter here; instead, we use
790 * percpu_ref_tryget directly, because we need to be able to
791 * obtain a reference even in the short window between the queue
792 * starting to freeze, by dropping the first reference in
793 * blk_freeze_queue_start, and the moment the last request is
794 * consumed, marked by the instant q_usage_counter reaches
797 if (!percpu_ref_tryget(&q
->q_usage_counter
))
800 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_expired
, &data
);
803 data
.next
= blk_rq_timeout(round_jiffies_up(data
.next
));
804 mod_timer(&q
->timeout
, data
.next
);
806 struct blk_mq_hw_ctx
*hctx
;
808 queue_for_each_hw_ctx(q
, hctx
, i
) {
809 /* the hctx may be unmapped, so check it here */
810 if (blk_mq_hw_queue_mapped(hctx
))
811 blk_mq_tag_idle(hctx
);
817 struct flush_busy_ctx_data
{
818 struct blk_mq_hw_ctx
*hctx
;
819 struct list_head
*list
;
822 static bool flush_busy_ctx(struct sbitmap
*sb
, unsigned int bitnr
, void *data
)
824 struct flush_busy_ctx_data
*flush_data
= data
;
825 struct blk_mq_hw_ctx
*hctx
= flush_data
->hctx
;
826 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
828 sbitmap_clear_bit(sb
, bitnr
);
829 spin_lock(&ctx
->lock
);
830 list_splice_tail_init(&ctx
->rq_list
, flush_data
->list
);
831 spin_unlock(&ctx
->lock
);
836 * Process software queues that have been marked busy, splicing them
837 * to the for-dispatch
839 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
841 struct flush_busy_ctx_data data
= {
846 sbitmap_for_each_set(&hctx
->ctx_map
, flush_busy_ctx
, &data
);
848 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs
);
850 static inline unsigned int queued_to_index(unsigned int queued
)
855 return min(BLK_MQ_MAX_DISPATCH_ORDER
- 1, ilog2(queued
) + 1);
858 bool blk_mq_get_driver_tag(struct request
*rq
, struct blk_mq_hw_ctx
**hctx
,
861 struct blk_mq_alloc_data data
= {
863 .hctx
= blk_mq_map_queue(rq
->q
, rq
->mq_ctx
->cpu
),
864 .flags
= wait
? 0 : BLK_MQ_REQ_NOWAIT
,
867 might_sleep_if(wait
);
872 if (blk_mq_tag_is_reserved(data
.hctx
->sched_tags
, rq
->internal_tag
))
873 data
.flags
|= BLK_MQ_REQ_RESERVED
;
875 rq
->tag
= blk_mq_get_tag(&data
);
877 if (blk_mq_tag_busy(data
.hctx
)) {
878 rq
->rq_flags
|= RQF_MQ_INFLIGHT
;
879 atomic_inc(&data
.hctx
->nr_active
);
881 data
.hctx
->tags
->rqs
[rq
->tag
] = rq
;
887 return rq
->tag
!= -1;
890 static void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx
*hctx
,
893 blk_mq_put_tag(hctx
, hctx
->tags
, rq
->mq_ctx
, rq
->tag
);
896 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
) {
897 rq
->rq_flags
&= ~RQF_MQ_INFLIGHT
;
898 atomic_dec(&hctx
->nr_active
);
902 static void blk_mq_put_driver_tag_hctx(struct blk_mq_hw_ctx
*hctx
,
905 if (rq
->tag
== -1 || rq
->internal_tag
== -1)
908 __blk_mq_put_driver_tag(hctx
, rq
);
911 static void blk_mq_put_driver_tag(struct request
*rq
)
913 struct blk_mq_hw_ctx
*hctx
;
915 if (rq
->tag
== -1 || rq
->internal_tag
== -1)
918 hctx
= blk_mq_map_queue(rq
->q
, rq
->mq_ctx
->cpu
);
919 __blk_mq_put_driver_tag(hctx
, rq
);
923 * If we fail getting a driver tag because all the driver tags are already
924 * assigned and on the dispatch list, BUT the first entry does not have a
925 * tag, then we could deadlock. For that case, move entries with assigned
926 * driver tags to the front, leaving the set of tagged requests in the
927 * same order, and the untagged set in the same order.
929 static bool reorder_tags_to_front(struct list_head
*list
)
931 struct request
*rq
, *tmp
, *first
= NULL
;
933 list_for_each_entry_safe_reverse(rq
, tmp
, list
, queuelist
) {
937 list_move(&rq
->queuelist
, list
);
943 return first
!= NULL
;
946 static int blk_mq_dispatch_wake(wait_queue_entry_t
*wait
, unsigned mode
, int flags
,
949 struct blk_mq_hw_ctx
*hctx
;
951 hctx
= container_of(wait
, struct blk_mq_hw_ctx
, dispatch_wait
);
953 list_del(&wait
->entry
);
954 clear_bit_unlock(BLK_MQ_S_TAG_WAITING
, &hctx
->state
);
955 blk_mq_run_hw_queue(hctx
, true);
959 static bool blk_mq_dispatch_wait_add(struct blk_mq_hw_ctx
*hctx
)
961 struct sbq_wait_state
*ws
;
964 * The TAG_WAITING bit serves as a lock protecting hctx->dispatch_wait.
965 * The thread which wins the race to grab this bit adds the hardware
966 * queue to the wait queue.
968 if (test_bit(BLK_MQ_S_TAG_WAITING
, &hctx
->state
) ||
969 test_and_set_bit_lock(BLK_MQ_S_TAG_WAITING
, &hctx
->state
))
972 init_waitqueue_func_entry(&hctx
->dispatch_wait
, blk_mq_dispatch_wake
);
973 ws
= bt_wait_ptr(&hctx
->tags
->bitmap_tags
, hctx
);
976 * As soon as this returns, it's no longer safe to fiddle with
977 * hctx->dispatch_wait, since a completion can wake up the wait queue
978 * and unlock the bit.
980 add_wait_queue(&ws
->wait
, &hctx
->dispatch_wait
);
984 bool blk_mq_dispatch_rq_list(struct request_queue
*q
, struct list_head
*list
)
986 struct blk_mq_hw_ctx
*hctx
;
990 if (list_empty(list
))
994 * Now process all the entries, sending them to the driver.
998 struct blk_mq_queue_data bd
;
1001 rq
= list_first_entry(list
, struct request
, queuelist
);
1002 if (!blk_mq_get_driver_tag(rq
, &hctx
, false)) {
1003 if (!queued
&& reorder_tags_to_front(list
))
1007 * The initial allocation attempt failed, so we need to
1008 * rerun the hardware queue when a tag is freed.
1010 if (!blk_mq_dispatch_wait_add(hctx
))
1014 * It's possible that a tag was freed in the window
1015 * between the allocation failure and adding the
1016 * hardware queue to the wait queue.
1018 if (!blk_mq_get_driver_tag(rq
, &hctx
, false))
1022 list_del_init(&rq
->queuelist
);
1027 * Flag last if we have no more requests, or if we have more
1028 * but can't assign a driver tag to it.
1030 if (list_empty(list
))
1033 struct request
*nxt
;
1035 nxt
= list_first_entry(list
, struct request
, queuelist
);
1036 bd
.last
= !blk_mq_get_driver_tag(nxt
, NULL
, false);
1039 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1040 if (ret
== BLK_STS_RESOURCE
) {
1041 blk_mq_put_driver_tag_hctx(hctx
, rq
);
1042 list_add(&rq
->queuelist
, list
);
1043 __blk_mq_requeue_request(rq
);
1047 if (unlikely(ret
!= BLK_STS_OK
)) {
1049 blk_mq_end_request(rq
, BLK_STS_IOERR
);
1054 } while (!list_empty(list
));
1056 hctx
->dispatched
[queued_to_index(queued
)]++;
1059 * Any items that need requeuing? Stuff them into hctx->dispatch,
1060 * that is where we will continue on next queue run.
1062 if (!list_empty(list
)) {
1064 * If an I/O scheduler has been configured and we got a driver
1065 * tag for the next request already, free it again.
1067 rq
= list_first_entry(list
, struct request
, queuelist
);
1068 blk_mq_put_driver_tag(rq
);
1070 spin_lock(&hctx
->lock
);
1071 list_splice_init(list
, &hctx
->dispatch
);
1072 spin_unlock(&hctx
->lock
);
1075 * If SCHED_RESTART was set by the caller of this function and
1076 * it is no longer set that means that it was cleared by another
1077 * thread and hence that a queue rerun is needed.
1079 * If TAG_WAITING is set that means that an I/O scheduler has
1080 * been configured and another thread is waiting for a driver
1081 * tag. To guarantee fairness, do not rerun this hardware queue
1082 * but let the other thread grab the driver tag.
1084 * If no I/O scheduler has been configured it is possible that
1085 * the hardware queue got stopped and restarted before requests
1086 * were pushed back onto the dispatch list. Rerun the queue to
1087 * avoid starvation. Notes:
1088 * - blk_mq_run_hw_queue() checks whether or not a queue has
1089 * been stopped before rerunning a queue.
1090 * - Some but not all block drivers stop a queue before
1091 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
1094 if (!blk_mq_sched_needs_restart(hctx
) &&
1095 !test_bit(BLK_MQ_S_TAG_WAITING
, &hctx
->state
))
1096 blk_mq_run_hw_queue(hctx
, true);
1099 return (queued
+ errors
) != 0;
1102 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1106 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
) &&
1107 cpu_online(hctx
->next_cpu
));
1109 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1111 blk_mq_sched_dispatch_requests(hctx
);
1116 srcu_idx
= srcu_read_lock(hctx
->queue_rq_srcu
);
1117 blk_mq_sched_dispatch_requests(hctx
);
1118 srcu_read_unlock(hctx
->queue_rq_srcu
, srcu_idx
);
1123 * It'd be great if the workqueue API had a way to pass
1124 * in a mask and had some smarts for more clever placement.
1125 * For now we just round-robin here, switching for every
1126 * BLK_MQ_CPU_WORK_BATCH queued items.
1128 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
1130 if (hctx
->queue
->nr_hw_queues
== 1)
1131 return WORK_CPU_UNBOUND
;
1133 if (--hctx
->next_cpu_batch
<= 0) {
1136 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
1137 if (next_cpu
>= nr_cpu_ids
)
1138 next_cpu
= cpumask_first(hctx
->cpumask
);
1140 hctx
->next_cpu
= next_cpu
;
1141 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1144 return hctx
->next_cpu
;
1147 static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
,
1148 unsigned long msecs
)
1150 if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx
)))
1153 if (unlikely(blk_mq_hctx_stopped(hctx
)))
1156 if (!async
&& !(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1157 int cpu
= get_cpu();
1158 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
1159 __blk_mq_run_hw_queue(hctx
);
1167 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
1169 msecs_to_jiffies(msecs
));
1172 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1174 __blk_mq_delay_run_hw_queue(hctx
, true, msecs
);
1176 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue
);
1178 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1180 __blk_mq_delay_run_hw_queue(hctx
, async
, 0);
1182 EXPORT_SYMBOL(blk_mq_run_hw_queue
);
1184 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
1186 struct blk_mq_hw_ctx
*hctx
;
1189 queue_for_each_hw_ctx(q
, hctx
, i
) {
1190 if (!blk_mq_hctx_has_pending(hctx
) ||
1191 blk_mq_hctx_stopped(hctx
))
1194 blk_mq_run_hw_queue(hctx
, async
);
1197 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
1200 * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
1201 * @q: request queue.
1203 * The caller is responsible for serializing this function against
1204 * blk_mq_{start,stop}_hw_queue().
1206 bool blk_mq_queue_stopped(struct request_queue
*q
)
1208 struct blk_mq_hw_ctx
*hctx
;
1211 queue_for_each_hw_ctx(q
, hctx
, i
)
1212 if (blk_mq_hctx_stopped(hctx
))
1217 EXPORT_SYMBOL(blk_mq_queue_stopped
);
1220 * This function is often used for pausing .queue_rq() by driver when
1221 * there isn't enough resource or some conditions aren't satisfied, and
1222 * BLK_MQ_RQ_QUEUE_BUSY is usually returned.
1224 * We do not guarantee that dispatch can be drained or blocked
1225 * after blk_mq_stop_hw_queue() returns. Please use
1226 * blk_mq_quiesce_queue() for that requirement.
1228 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1230 cancel_delayed_work(&hctx
->run_work
);
1232 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1234 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
1237 * This function is often used for pausing .queue_rq() by driver when
1238 * there isn't enough resource or some conditions aren't satisfied, and
1239 * BLK_MQ_RQ_QUEUE_BUSY is usually returned.
1241 * We do not guarantee that dispatch can be drained or blocked
1242 * after blk_mq_stop_hw_queues() returns. Please use
1243 * blk_mq_quiesce_queue() for that requirement.
1245 void blk_mq_stop_hw_queues(struct request_queue
*q
)
1247 struct blk_mq_hw_ctx
*hctx
;
1250 queue_for_each_hw_ctx(q
, hctx
, i
)
1251 blk_mq_stop_hw_queue(hctx
);
1253 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
1255 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1257 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1259 blk_mq_run_hw_queue(hctx
, false);
1261 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
1263 void blk_mq_start_hw_queues(struct request_queue
*q
)
1265 struct blk_mq_hw_ctx
*hctx
;
1268 queue_for_each_hw_ctx(q
, hctx
, i
)
1269 blk_mq_start_hw_queue(hctx
);
1271 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
1273 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1275 if (!blk_mq_hctx_stopped(hctx
))
1278 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1279 blk_mq_run_hw_queue(hctx
, async
);
1281 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue
);
1283 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
1285 struct blk_mq_hw_ctx
*hctx
;
1288 queue_for_each_hw_ctx(q
, hctx
, i
)
1289 blk_mq_start_stopped_hw_queue(hctx
, async
);
1291 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
1293 static void blk_mq_run_work_fn(struct work_struct
*work
)
1295 struct blk_mq_hw_ctx
*hctx
;
1297 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
1300 * If we are stopped, don't run the queue. The exception is if
1301 * BLK_MQ_S_START_ON_RUN is set. For that case, we auto-clear
1302 * the STOPPED bit and run it.
1304 if (test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)) {
1305 if (!test_bit(BLK_MQ_S_START_ON_RUN
, &hctx
->state
))
1308 clear_bit(BLK_MQ_S_START_ON_RUN
, &hctx
->state
);
1309 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1312 __blk_mq_run_hw_queue(hctx
);
1316 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1318 if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx
)))
1322 * Stop the hw queue, then modify currently delayed work.
1323 * This should prevent us from running the queue prematurely.
1324 * Mark the queue as auto-clearing STOPPED when it runs.
1326 blk_mq_stop_hw_queue(hctx
);
1327 set_bit(BLK_MQ_S_START_ON_RUN
, &hctx
->state
);
1328 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
1330 msecs_to_jiffies(msecs
));
1332 EXPORT_SYMBOL(blk_mq_delay_queue
);
1334 static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx
*hctx
,
1338 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1340 lockdep_assert_held(&ctx
->lock
);
1342 trace_block_rq_insert(hctx
->queue
, rq
);
1345 list_add(&rq
->queuelist
, &ctx
->rq_list
);
1347 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
1350 void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
1353 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1355 lockdep_assert_held(&ctx
->lock
);
1357 __blk_mq_insert_req_list(hctx
, rq
, at_head
);
1358 blk_mq_hctx_mark_pending(hctx
, ctx
);
1361 void blk_mq_insert_requests(struct blk_mq_hw_ctx
*hctx
, struct blk_mq_ctx
*ctx
,
1362 struct list_head
*list
)
1366 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1369 spin_lock(&ctx
->lock
);
1370 while (!list_empty(list
)) {
1373 rq
= list_first_entry(list
, struct request
, queuelist
);
1374 BUG_ON(rq
->mq_ctx
!= ctx
);
1375 list_del_init(&rq
->queuelist
);
1376 __blk_mq_insert_req_list(hctx
, rq
, false);
1378 blk_mq_hctx_mark_pending(hctx
, ctx
);
1379 spin_unlock(&ctx
->lock
);
1382 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1384 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1385 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1387 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1388 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1389 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1392 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1394 struct blk_mq_ctx
*this_ctx
;
1395 struct request_queue
*this_q
;
1398 LIST_HEAD(ctx_list
);
1401 list_splice_init(&plug
->mq_list
, &list
);
1403 list_sort(NULL
, &list
, plug_ctx_cmp
);
1409 while (!list_empty(&list
)) {
1410 rq
= list_entry_rq(list
.next
);
1411 list_del_init(&rq
->queuelist
);
1413 if (rq
->mq_ctx
!= this_ctx
) {
1415 trace_block_unplug(this_q
, depth
, from_schedule
);
1416 blk_mq_sched_insert_requests(this_q
, this_ctx
,
1421 this_ctx
= rq
->mq_ctx
;
1427 list_add_tail(&rq
->queuelist
, &ctx_list
);
1431 * If 'this_ctx' is set, we know we have entries to complete
1432 * on 'ctx_list'. Do those.
1435 trace_block_unplug(this_q
, depth
, from_schedule
);
1436 blk_mq_sched_insert_requests(this_q
, this_ctx
, &ctx_list
,
1441 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1443 blk_init_request_from_bio(rq
, bio
);
1445 blk_account_io_start(rq
, true);
1448 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1450 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1451 !blk_queue_nomerges(hctx
->queue
);
1454 static inline void blk_mq_queue_io(struct blk_mq_hw_ctx
*hctx
,
1455 struct blk_mq_ctx
*ctx
,
1458 spin_lock(&ctx
->lock
);
1459 __blk_mq_insert_request(hctx
, rq
, false);
1460 spin_unlock(&ctx
->lock
);
1463 static blk_qc_t
request_to_qc_t(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
1466 return blk_tag_to_qc_t(rq
->tag
, hctx
->queue_num
, false);
1468 return blk_tag_to_qc_t(rq
->internal_tag
, hctx
->queue_num
, true);
1471 static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1473 blk_qc_t
*cookie
, bool may_sleep
)
1475 struct request_queue
*q
= rq
->q
;
1476 struct blk_mq_queue_data bd
= {
1480 blk_qc_t new_cookie
;
1482 bool run_queue
= true;
1484 /* RCU or SRCU read lock is needed before checking quiesced flag */
1485 if (blk_mq_hctx_stopped(hctx
) || blk_queue_quiesced(q
)) {
1493 if (!blk_mq_get_driver_tag(rq
, NULL
, false))
1496 new_cookie
= request_to_qc_t(hctx
, rq
);
1499 * For OK queue, we are done. For error, kill it. Any other
1500 * error (busy), just add it to our list as we previously
1503 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1506 *cookie
= new_cookie
;
1508 case BLK_STS_RESOURCE
:
1509 __blk_mq_requeue_request(rq
);
1512 *cookie
= BLK_QC_T_NONE
;
1513 blk_mq_end_request(rq
, ret
);
1518 blk_mq_sched_insert_request(rq
, false, run_queue
, false, may_sleep
);
1521 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1522 struct request
*rq
, blk_qc_t
*cookie
)
1524 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1526 __blk_mq_try_issue_directly(hctx
, rq
, cookie
, false);
1529 unsigned int srcu_idx
;
1533 srcu_idx
= srcu_read_lock(hctx
->queue_rq_srcu
);
1534 __blk_mq_try_issue_directly(hctx
, rq
, cookie
, true);
1535 srcu_read_unlock(hctx
->queue_rq_srcu
, srcu_idx
);
1539 static blk_qc_t
blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1541 const int is_sync
= op_is_sync(bio
->bi_opf
);
1542 const int is_flush_fua
= op_is_flush(bio
->bi_opf
);
1543 struct blk_mq_alloc_data data
= { .flags
= 0 };
1545 unsigned int request_count
= 0;
1546 struct blk_plug
*plug
;
1547 struct request
*same_queue_rq
= NULL
;
1549 unsigned int wb_acct
;
1551 blk_queue_bounce(q
, &bio
);
1553 blk_queue_split(q
, &bio
);
1555 if (!bio_integrity_prep(bio
))
1556 return BLK_QC_T_NONE
;
1558 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
1559 blk_attempt_plug_merge(q
, bio
, &request_count
, &same_queue_rq
))
1560 return BLK_QC_T_NONE
;
1562 if (blk_mq_sched_bio_merge(q
, bio
))
1563 return BLK_QC_T_NONE
;
1565 wb_acct
= wbt_wait(q
->rq_wb
, bio
, NULL
);
1567 trace_block_getrq(q
, bio
, bio
->bi_opf
);
1569 rq
= blk_mq_get_request(q
, bio
, bio
->bi_opf
, &data
);
1570 if (unlikely(!rq
)) {
1571 __wbt_done(q
->rq_wb
, wb_acct
);
1572 if (bio
->bi_opf
& REQ_NOWAIT
)
1573 bio_wouldblock_error(bio
);
1574 return BLK_QC_T_NONE
;
1577 wbt_track(&rq
->issue_stat
, wb_acct
);
1579 cookie
= request_to_qc_t(data
.hctx
, rq
);
1581 plug
= current
->plug
;
1582 if (unlikely(is_flush_fua
)) {
1583 blk_mq_put_ctx(data
.ctx
);
1584 blk_mq_bio_to_request(rq
, bio
);
1586 blk_mq_sched_insert_request(rq
, false, true, true,
1589 blk_insert_flush(rq
);
1590 blk_mq_run_hw_queue(data
.hctx
, true);
1592 } else if (plug
&& q
->nr_hw_queues
== 1) {
1593 struct request
*last
= NULL
;
1595 blk_mq_put_ctx(data
.ctx
);
1596 blk_mq_bio_to_request(rq
, bio
);
1599 * @request_count may become stale because of schedule
1600 * out, so check the list again.
1602 if (list_empty(&plug
->mq_list
))
1604 else if (blk_queue_nomerges(q
))
1605 request_count
= blk_plug_queued_count(q
);
1608 trace_block_plug(q
);
1610 last
= list_entry_rq(plug
->mq_list
.prev
);
1612 if (request_count
>= BLK_MAX_REQUEST_COUNT
|| (last
&&
1613 blk_rq_bytes(last
) >= BLK_PLUG_FLUSH_SIZE
)) {
1614 blk_flush_plug_list(plug
, false);
1615 trace_block_plug(q
);
1618 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1619 } else if (plug
&& !blk_queue_nomerges(q
)) {
1620 blk_mq_bio_to_request(rq
, bio
);
1623 * We do limited plugging. If the bio can be merged, do that.
1624 * Otherwise the existing request in the plug list will be
1625 * issued. So the plug list will have one request at most
1626 * The plug list might get flushed before this. If that happens,
1627 * the plug list is empty, and same_queue_rq is invalid.
1629 if (list_empty(&plug
->mq_list
))
1630 same_queue_rq
= NULL
;
1632 list_del_init(&same_queue_rq
->queuelist
);
1633 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1635 blk_mq_put_ctx(data
.ctx
);
1637 if (same_queue_rq
) {
1638 data
.hctx
= blk_mq_map_queue(q
,
1639 same_queue_rq
->mq_ctx
->cpu
);
1640 blk_mq_try_issue_directly(data
.hctx
, same_queue_rq
,
1643 } else if (q
->nr_hw_queues
> 1 && is_sync
) {
1644 blk_mq_put_ctx(data
.ctx
);
1645 blk_mq_bio_to_request(rq
, bio
);
1646 blk_mq_try_issue_directly(data
.hctx
, rq
, &cookie
);
1647 } else if (q
->elevator
) {
1648 blk_mq_put_ctx(data
.ctx
);
1649 blk_mq_bio_to_request(rq
, bio
);
1650 blk_mq_sched_insert_request(rq
, false, true, true, true);
1652 blk_mq_put_ctx(data
.ctx
);
1653 blk_mq_bio_to_request(rq
, bio
);
1654 blk_mq_queue_io(data
.hctx
, data
.ctx
, rq
);
1655 blk_mq_run_hw_queue(data
.hctx
, true);
1661 void blk_mq_free_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
1662 unsigned int hctx_idx
)
1666 if (tags
->rqs
&& set
->ops
->exit_request
) {
1669 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1670 struct request
*rq
= tags
->static_rqs
[i
];
1674 set
->ops
->exit_request(set
, rq
, hctx_idx
);
1675 tags
->static_rqs
[i
] = NULL
;
1679 while (!list_empty(&tags
->page_list
)) {
1680 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1681 list_del_init(&page
->lru
);
1683 * Remove kmemleak object previously allocated in
1684 * blk_mq_init_rq_map().
1686 kmemleak_free(page_address(page
));
1687 __free_pages(page
, page
->private);
1691 void blk_mq_free_rq_map(struct blk_mq_tags
*tags
)
1695 kfree(tags
->static_rqs
);
1696 tags
->static_rqs
= NULL
;
1698 blk_mq_free_tags(tags
);
1701 struct blk_mq_tags
*blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
,
1702 unsigned int hctx_idx
,
1703 unsigned int nr_tags
,
1704 unsigned int reserved_tags
)
1706 struct blk_mq_tags
*tags
;
1709 node
= blk_mq_hw_queue_to_node(set
->mq_map
, hctx_idx
);
1710 if (node
== NUMA_NO_NODE
)
1711 node
= set
->numa_node
;
1713 tags
= blk_mq_init_tags(nr_tags
, reserved_tags
, node
,
1714 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
1718 tags
->rqs
= kzalloc_node(nr_tags
* sizeof(struct request
*),
1719 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
1722 blk_mq_free_tags(tags
);
1726 tags
->static_rqs
= kzalloc_node(nr_tags
* sizeof(struct request
*),
1727 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
1729 if (!tags
->static_rqs
) {
1731 blk_mq_free_tags(tags
);
1738 static size_t order_to_size(unsigned int order
)
1740 return (size_t)PAGE_SIZE
<< order
;
1743 int blk_mq_alloc_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
1744 unsigned int hctx_idx
, unsigned int depth
)
1746 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1747 size_t rq_size
, left
;
1750 node
= blk_mq_hw_queue_to_node(set
->mq_map
, hctx_idx
);
1751 if (node
== NUMA_NO_NODE
)
1752 node
= set
->numa_node
;
1754 INIT_LIST_HEAD(&tags
->page_list
);
1757 * rq_size is the size of the request plus driver payload, rounded
1758 * to the cacheline size
1760 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1762 left
= rq_size
* depth
;
1764 for (i
= 0; i
< depth
; ) {
1765 int this_order
= max_order
;
1770 while (this_order
&& left
< order_to_size(this_order
- 1))
1774 page
= alloc_pages_node(node
,
1775 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
1781 if (order_to_size(this_order
) < rq_size
)
1788 page
->private = this_order
;
1789 list_add_tail(&page
->lru
, &tags
->page_list
);
1791 p
= page_address(page
);
1793 * Allow kmemleak to scan these pages as they contain pointers
1794 * to additional allocations like via ops->init_request().
1796 kmemleak_alloc(p
, order_to_size(this_order
), 1, GFP_NOIO
);
1797 entries_per_page
= order_to_size(this_order
) / rq_size
;
1798 to_do
= min(entries_per_page
, depth
- i
);
1799 left
-= to_do
* rq_size
;
1800 for (j
= 0; j
< to_do
; j
++) {
1801 struct request
*rq
= p
;
1803 tags
->static_rqs
[i
] = rq
;
1804 if (set
->ops
->init_request
) {
1805 if (set
->ops
->init_request(set
, rq
, hctx_idx
,
1807 tags
->static_rqs
[i
] = NULL
;
1819 blk_mq_free_rqs(set
, tags
, hctx_idx
);
1824 * 'cpu' is going away. splice any existing rq_list entries from this
1825 * software queue to the hw queue dispatch list, and ensure that it
1828 static int blk_mq_hctx_notify_dead(unsigned int cpu
, struct hlist_node
*node
)
1830 struct blk_mq_hw_ctx
*hctx
;
1831 struct blk_mq_ctx
*ctx
;
1834 hctx
= hlist_entry_safe(node
, struct blk_mq_hw_ctx
, cpuhp_dead
);
1835 ctx
= __blk_mq_get_ctx(hctx
->queue
, cpu
);
1837 spin_lock(&ctx
->lock
);
1838 if (!list_empty(&ctx
->rq_list
)) {
1839 list_splice_init(&ctx
->rq_list
, &tmp
);
1840 blk_mq_hctx_clear_pending(hctx
, ctx
);
1842 spin_unlock(&ctx
->lock
);
1844 if (list_empty(&tmp
))
1847 spin_lock(&hctx
->lock
);
1848 list_splice_tail_init(&tmp
, &hctx
->dispatch
);
1849 spin_unlock(&hctx
->lock
);
1851 blk_mq_run_hw_queue(hctx
, true);
1855 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx
*hctx
)
1857 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD
,
1861 /* hctx->ctxs will be freed in queue's release handler */
1862 static void blk_mq_exit_hctx(struct request_queue
*q
,
1863 struct blk_mq_tag_set
*set
,
1864 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1866 blk_mq_debugfs_unregister_hctx(hctx
);
1868 blk_mq_tag_idle(hctx
);
1870 if (set
->ops
->exit_request
)
1871 set
->ops
->exit_request(set
, hctx
->fq
->flush_rq
, hctx_idx
);
1873 blk_mq_sched_exit_hctx(q
, hctx
, hctx_idx
);
1875 if (set
->ops
->exit_hctx
)
1876 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1878 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
1879 cleanup_srcu_struct(hctx
->queue_rq_srcu
);
1881 blk_mq_remove_cpuhp(hctx
);
1882 blk_free_flush_queue(hctx
->fq
);
1883 sbitmap_free(&hctx
->ctx_map
);
1886 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1887 struct blk_mq_tag_set
*set
, int nr_queue
)
1889 struct blk_mq_hw_ctx
*hctx
;
1892 queue_for_each_hw_ctx(q
, hctx
, i
) {
1895 blk_mq_exit_hctx(q
, set
, hctx
, i
);
1899 static int blk_mq_init_hctx(struct request_queue
*q
,
1900 struct blk_mq_tag_set
*set
,
1901 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
1905 node
= hctx
->numa_node
;
1906 if (node
== NUMA_NO_NODE
)
1907 node
= hctx
->numa_node
= set
->numa_node
;
1909 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1910 spin_lock_init(&hctx
->lock
);
1911 INIT_LIST_HEAD(&hctx
->dispatch
);
1913 hctx
->flags
= set
->flags
& ~BLK_MQ_F_TAG_SHARED
;
1915 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD
, &hctx
->cpuhp_dead
);
1917 hctx
->tags
= set
->tags
[hctx_idx
];
1920 * Allocate space for all possible cpus to avoid allocation at
1923 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1926 goto unregister_cpu_notifier
;
1928 if (sbitmap_init_node(&hctx
->ctx_map
, nr_cpu_ids
, ilog2(8), GFP_KERNEL
,
1934 if (set
->ops
->init_hctx
&&
1935 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
1938 if (blk_mq_sched_init_hctx(q
, hctx
, hctx_idx
))
1941 hctx
->fq
= blk_alloc_flush_queue(q
, hctx
->numa_node
, set
->cmd_size
);
1943 goto sched_exit_hctx
;
1945 if (set
->ops
->init_request
&&
1946 set
->ops
->init_request(set
, hctx
->fq
->flush_rq
, hctx_idx
,
1950 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
1951 init_srcu_struct(hctx
->queue_rq_srcu
);
1953 blk_mq_debugfs_register_hctx(q
, hctx
);
1960 blk_mq_sched_exit_hctx(q
, hctx
, hctx_idx
);
1962 if (set
->ops
->exit_hctx
)
1963 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1965 sbitmap_free(&hctx
->ctx_map
);
1968 unregister_cpu_notifier
:
1969 blk_mq_remove_cpuhp(hctx
);
1973 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1974 unsigned int nr_hw_queues
)
1978 for_each_possible_cpu(i
) {
1979 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1980 struct blk_mq_hw_ctx
*hctx
;
1983 spin_lock_init(&__ctx
->lock
);
1984 INIT_LIST_HEAD(&__ctx
->rq_list
);
1987 /* If the cpu isn't present, the cpu is mapped to first hctx */
1988 if (!cpu_present(i
))
1991 hctx
= blk_mq_map_queue(q
, i
);
1994 * Set local node, IFF we have more than one hw queue. If
1995 * not, we remain on the home node of the device
1997 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1998 hctx
->numa_node
= local_memory_node(cpu_to_node(i
));
2002 static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
, int hctx_idx
)
2006 set
->tags
[hctx_idx
] = blk_mq_alloc_rq_map(set
, hctx_idx
,
2007 set
->queue_depth
, set
->reserved_tags
);
2008 if (!set
->tags
[hctx_idx
])
2011 ret
= blk_mq_alloc_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
,
2016 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2017 set
->tags
[hctx_idx
] = NULL
;
2021 static void blk_mq_free_map_and_requests(struct blk_mq_tag_set
*set
,
2022 unsigned int hctx_idx
)
2024 if (set
->tags
[hctx_idx
]) {
2025 blk_mq_free_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
);
2026 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2027 set
->tags
[hctx_idx
] = NULL
;
2031 static void blk_mq_map_swqueue(struct request_queue
*q
)
2033 unsigned int i
, hctx_idx
;
2034 struct blk_mq_hw_ctx
*hctx
;
2035 struct blk_mq_ctx
*ctx
;
2036 struct blk_mq_tag_set
*set
= q
->tag_set
;
2039 * Avoid others reading imcomplete hctx->cpumask through sysfs
2041 mutex_lock(&q
->sysfs_lock
);
2043 queue_for_each_hw_ctx(q
, hctx
, i
) {
2044 cpumask_clear(hctx
->cpumask
);
2049 * Map software to hardware queues.
2051 * If the cpu isn't present, the cpu is mapped to first hctx.
2053 for_each_present_cpu(i
) {
2054 hctx_idx
= q
->mq_map
[i
];
2055 /* unmapped hw queue can be remapped after CPU topo changed */
2056 if (!set
->tags
[hctx_idx
] &&
2057 !__blk_mq_alloc_rq_map(set
, hctx_idx
)) {
2059 * If tags initialization fail for some hctx,
2060 * that hctx won't be brought online. In this
2061 * case, remap the current ctx to hctx[0] which
2062 * is guaranteed to always have tags allocated
2067 ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
2068 hctx
= blk_mq_map_queue(q
, i
);
2070 cpumask_set_cpu(i
, hctx
->cpumask
);
2071 ctx
->index_hw
= hctx
->nr_ctx
;
2072 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
2075 mutex_unlock(&q
->sysfs_lock
);
2077 queue_for_each_hw_ctx(q
, hctx
, i
) {
2079 * If no software queues are mapped to this hardware queue,
2080 * disable it and free the request entries.
2082 if (!hctx
->nr_ctx
) {
2083 /* Never unmap queue 0. We need it as a
2084 * fallback in case of a new remap fails
2087 if (i
&& set
->tags
[i
])
2088 blk_mq_free_map_and_requests(set
, i
);
2094 hctx
->tags
= set
->tags
[i
];
2095 WARN_ON(!hctx
->tags
);
2098 * Set the map size to the number of mapped software queues.
2099 * This is more accurate and more efficient than looping
2100 * over all possibly mapped software queues.
2102 sbitmap_resize(&hctx
->ctx_map
, hctx
->nr_ctx
);
2105 * Initialize batch roundrobin counts
2107 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
2108 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
2113 * Caller needs to ensure that we're either frozen/quiesced, or that
2114 * the queue isn't live yet.
2116 static void queue_set_hctx_shared(struct request_queue
*q
, bool shared
)
2118 struct blk_mq_hw_ctx
*hctx
;
2121 queue_for_each_hw_ctx(q
, hctx
, i
) {
2123 if (test_bit(BLK_MQ_S_SCHED_RESTART
, &hctx
->state
))
2124 atomic_inc(&q
->shared_hctx_restart
);
2125 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
2127 if (test_bit(BLK_MQ_S_SCHED_RESTART
, &hctx
->state
))
2128 atomic_dec(&q
->shared_hctx_restart
);
2129 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2134 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
,
2137 struct request_queue
*q
;
2139 lockdep_assert_held(&set
->tag_list_lock
);
2141 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
2142 blk_mq_freeze_queue(q
);
2143 queue_set_hctx_shared(q
, shared
);
2144 blk_mq_unfreeze_queue(q
);
2148 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
2150 struct blk_mq_tag_set
*set
= q
->tag_set
;
2152 mutex_lock(&set
->tag_list_lock
);
2153 list_del_rcu(&q
->tag_set_list
);
2154 INIT_LIST_HEAD(&q
->tag_set_list
);
2155 if (list_is_singular(&set
->tag_list
)) {
2156 /* just transitioned to unshared */
2157 set
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2158 /* update existing queue */
2159 blk_mq_update_tag_set_depth(set
, false);
2161 mutex_unlock(&set
->tag_list_lock
);
2166 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
2167 struct request_queue
*q
)
2171 mutex_lock(&set
->tag_list_lock
);
2173 /* Check to see if we're transitioning to shared (from 1 to 2 queues). */
2174 if (!list_empty(&set
->tag_list
) && !(set
->flags
& BLK_MQ_F_TAG_SHARED
)) {
2175 set
->flags
|= BLK_MQ_F_TAG_SHARED
;
2176 /* update existing queue */
2177 blk_mq_update_tag_set_depth(set
, true);
2179 if (set
->flags
& BLK_MQ_F_TAG_SHARED
)
2180 queue_set_hctx_shared(q
, true);
2181 list_add_tail_rcu(&q
->tag_set_list
, &set
->tag_list
);
2183 mutex_unlock(&set
->tag_list_lock
);
2187 * It is the actual release handler for mq, but we do it from
2188 * request queue's release handler for avoiding use-after-free
2189 * and headache because q->mq_kobj shouldn't have been introduced,
2190 * but we can't group ctx/kctx kobj without it.
2192 void blk_mq_release(struct request_queue
*q
)
2194 struct blk_mq_hw_ctx
*hctx
;
2197 /* hctx kobj stays in hctx */
2198 queue_for_each_hw_ctx(q
, hctx
, i
) {
2201 kobject_put(&hctx
->kobj
);
2206 kfree(q
->queue_hw_ctx
);
2209 * release .mq_kobj and sw queue's kobject now because
2210 * both share lifetime with request queue.
2212 blk_mq_sysfs_deinit(q
);
2214 free_percpu(q
->queue_ctx
);
2217 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
2219 struct request_queue
*uninit_q
, *q
;
2221 uninit_q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
2223 return ERR_PTR(-ENOMEM
);
2225 q
= blk_mq_init_allocated_queue(set
, uninit_q
);
2227 blk_cleanup_queue(uninit_q
);
2231 EXPORT_SYMBOL(blk_mq_init_queue
);
2233 static int blk_mq_hw_ctx_size(struct blk_mq_tag_set
*tag_set
)
2235 int hw_ctx_size
= sizeof(struct blk_mq_hw_ctx
);
2237 BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx
, queue_rq_srcu
),
2238 __alignof__(struct blk_mq_hw_ctx
)) !=
2239 sizeof(struct blk_mq_hw_ctx
));
2241 if (tag_set
->flags
& BLK_MQ_F_BLOCKING
)
2242 hw_ctx_size
+= sizeof(struct srcu_struct
);
2247 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set
*set
,
2248 struct request_queue
*q
)
2251 struct blk_mq_hw_ctx
**hctxs
= q
->queue_hw_ctx
;
2253 blk_mq_sysfs_unregister(q
);
2254 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2260 node
= blk_mq_hw_queue_to_node(q
->mq_map
, i
);
2261 hctxs
[i
] = kzalloc_node(blk_mq_hw_ctx_size(set
),
2266 if (!zalloc_cpumask_var_node(&hctxs
[i
]->cpumask
, GFP_KERNEL
,
2273 atomic_set(&hctxs
[i
]->nr_active
, 0);
2274 hctxs
[i
]->numa_node
= node
;
2275 hctxs
[i
]->queue_num
= i
;
2277 if (blk_mq_init_hctx(q
, set
, hctxs
[i
], i
)) {
2278 free_cpumask_var(hctxs
[i
]->cpumask
);
2283 blk_mq_hctx_kobj_init(hctxs
[i
]);
2285 for (j
= i
; j
< q
->nr_hw_queues
; j
++) {
2286 struct blk_mq_hw_ctx
*hctx
= hctxs
[j
];
2290 blk_mq_free_map_and_requests(set
, j
);
2291 blk_mq_exit_hctx(q
, set
, hctx
, j
);
2292 kobject_put(&hctx
->kobj
);
2297 q
->nr_hw_queues
= i
;
2298 blk_mq_sysfs_register(q
);
2301 struct request_queue
*blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
2302 struct request_queue
*q
)
2304 /* mark the queue as mq asap */
2305 q
->mq_ops
= set
->ops
;
2307 q
->poll_cb
= blk_stat_alloc_callback(blk_mq_poll_stats_fn
,
2308 blk_mq_poll_stats_bkt
,
2309 BLK_MQ_POLL_STATS_BKTS
, q
);
2313 q
->queue_ctx
= alloc_percpu(struct blk_mq_ctx
);
2317 /* init q->mq_kobj and sw queues' kobjects */
2318 blk_mq_sysfs_init(q
);
2320 q
->queue_hw_ctx
= kzalloc_node(nr_cpu_ids
* sizeof(*(q
->queue_hw_ctx
)),
2321 GFP_KERNEL
, set
->numa_node
);
2322 if (!q
->queue_hw_ctx
)
2325 q
->mq_map
= set
->mq_map
;
2327 blk_mq_realloc_hw_ctxs(set
, q
);
2328 if (!q
->nr_hw_queues
)
2331 INIT_WORK(&q
->timeout_work
, blk_mq_timeout_work
);
2332 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
2334 q
->nr_queues
= nr_cpu_ids
;
2336 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
2338 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
2339 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
2341 q
->sg_reserved_size
= INT_MAX
;
2343 INIT_DELAYED_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
2344 INIT_LIST_HEAD(&q
->requeue_list
);
2345 spin_lock_init(&q
->requeue_lock
);
2347 blk_queue_make_request(q
, blk_mq_make_request
);
2350 * Do this after blk_queue_make_request() overrides it...
2352 q
->nr_requests
= set
->queue_depth
;
2355 * Default to classic polling
2359 if (set
->ops
->complete
)
2360 blk_queue_softirq_done(q
, set
->ops
->complete
);
2362 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
2363 blk_mq_add_queue_tag_set(set
, q
);
2364 blk_mq_map_swqueue(q
);
2366 if (!(set
->flags
& BLK_MQ_F_NO_SCHED
)) {
2369 ret
= blk_mq_sched_init(q
);
2371 return ERR_PTR(ret
);
2377 kfree(q
->queue_hw_ctx
);
2379 free_percpu(q
->queue_ctx
);
2382 return ERR_PTR(-ENOMEM
);
2384 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
2386 void blk_mq_free_queue(struct request_queue
*q
)
2388 struct blk_mq_tag_set
*set
= q
->tag_set
;
2390 blk_mq_del_queue_tag_set(q
);
2391 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
2394 /* Basically redo blk_mq_init_queue with queue frozen */
2395 static void blk_mq_queue_reinit(struct request_queue
*q
)
2397 WARN_ON_ONCE(!atomic_read(&q
->mq_freeze_depth
));
2399 blk_mq_debugfs_unregister_hctxs(q
);
2400 blk_mq_sysfs_unregister(q
);
2403 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
2404 * we should change hctx numa_node according to new topology (this
2405 * involves free and re-allocate memory, worthy doing?)
2408 blk_mq_map_swqueue(q
);
2410 blk_mq_sysfs_register(q
);
2411 blk_mq_debugfs_register_hctxs(q
);
2414 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2418 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
2419 if (!__blk_mq_alloc_rq_map(set
, i
))
2426 blk_mq_free_rq_map(set
->tags
[i
]);
2432 * Allocate the request maps associated with this tag_set. Note that this
2433 * may reduce the depth asked for, if memory is tight. set->queue_depth
2434 * will be updated to reflect the allocated depth.
2436 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2441 depth
= set
->queue_depth
;
2443 err
= __blk_mq_alloc_rq_maps(set
);
2447 set
->queue_depth
>>= 1;
2448 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
2452 } while (set
->queue_depth
);
2454 if (!set
->queue_depth
|| err
) {
2455 pr_err("blk-mq: failed to allocate request map\n");
2459 if (depth
!= set
->queue_depth
)
2460 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2461 depth
, set
->queue_depth
);
2466 static int blk_mq_update_queue_map(struct blk_mq_tag_set
*set
)
2468 if (set
->ops
->map_queues
)
2469 return set
->ops
->map_queues(set
);
2471 return blk_mq_map_queues(set
);
2475 * Alloc a tag set to be associated with one or more request queues.
2476 * May fail with EINVAL for various error conditions. May adjust the
2477 * requested depth down, if if it too large. In that case, the set
2478 * value will be stored in set->queue_depth.
2480 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2484 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
2486 if (!set
->nr_hw_queues
)
2488 if (!set
->queue_depth
)
2490 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2493 if (!set
->ops
->queue_rq
)
2496 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2497 pr_info("blk-mq: reduced tag depth to %u\n",
2499 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2503 * If a crashdump is active, then we are potentially in a very
2504 * memory constrained environment. Limit us to 1 queue and
2505 * 64 tags to prevent using too much memory.
2507 if (is_kdump_kernel()) {
2508 set
->nr_hw_queues
= 1;
2509 set
->queue_depth
= min(64U, set
->queue_depth
);
2512 * There is no use for more h/w queues than cpus.
2514 if (set
->nr_hw_queues
> nr_cpu_ids
)
2515 set
->nr_hw_queues
= nr_cpu_ids
;
2517 set
->tags
= kzalloc_node(nr_cpu_ids
* sizeof(struct blk_mq_tags
*),
2518 GFP_KERNEL
, set
->numa_node
);
2523 set
->mq_map
= kzalloc_node(sizeof(*set
->mq_map
) * nr_cpu_ids
,
2524 GFP_KERNEL
, set
->numa_node
);
2528 ret
= blk_mq_update_queue_map(set
);
2530 goto out_free_mq_map
;
2532 ret
= blk_mq_alloc_rq_maps(set
);
2534 goto out_free_mq_map
;
2536 mutex_init(&set
->tag_list_lock
);
2537 INIT_LIST_HEAD(&set
->tag_list
);
2549 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2551 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2555 for (i
= 0; i
< nr_cpu_ids
; i
++)
2556 blk_mq_free_map_and_requests(set
, i
);
2564 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2566 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2568 struct blk_mq_tag_set
*set
= q
->tag_set
;
2569 struct blk_mq_hw_ctx
*hctx
;
2575 blk_mq_freeze_queue(q
);
2578 queue_for_each_hw_ctx(q
, hctx
, i
) {
2582 * If we're using an MQ scheduler, just update the scheduler
2583 * queue depth. This is similar to what the old code would do.
2585 if (!hctx
->sched_tags
) {
2586 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->tags
,
2587 min(nr
, set
->queue_depth
),
2590 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->sched_tags
,
2598 q
->nr_requests
= nr
;
2600 blk_mq_unfreeze_queue(q
);
2605 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
,
2608 struct request_queue
*q
;
2610 lockdep_assert_held(&set
->tag_list_lock
);
2612 if (nr_hw_queues
> nr_cpu_ids
)
2613 nr_hw_queues
= nr_cpu_ids
;
2614 if (nr_hw_queues
< 1 || nr_hw_queues
== set
->nr_hw_queues
)
2617 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
2618 blk_mq_freeze_queue(q
);
2620 set
->nr_hw_queues
= nr_hw_queues
;
2621 blk_mq_update_queue_map(set
);
2622 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
2623 blk_mq_realloc_hw_ctxs(set
, q
);
2624 blk_mq_queue_reinit(q
);
2627 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
2628 blk_mq_unfreeze_queue(q
);
2631 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
, int nr_hw_queues
)
2633 mutex_lock(&set
->tag_list_lock
);
2634 __blk_mq_update_nr_hw_queues(set
, nr_hw_queues
);
2635 mutex_unlock(&set
->tag_list_lock
);
2637 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues
);
2639 /* Enable polling stats and return whether they were already enabled. */
2640 static bool blk_poll_stats_enable(struct request_queue
*q
)
2642 if (test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
2643 test_and_set_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
))
2645 blk_stat_add_callback(q
, q
->poll_cb
);
2649 static void blk_mq_poll_stats_start(struct request_queue
*q
)
2652 * We don't arm the callback if polling stats are not enabled or the
2653 * callback is already active.
2655 if (!test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
2656 blk_stat_is_active(q
->poll_cb
))
2659 blk_stat_activate_msecs(q
->poll_cb
, 100);
2662 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
)
2664 struct request_queue
*q
= cb
->data
;
2667 for (bucket
= 0; bucket
< BLK_MQ_POLL_STATS_BKTS
; bucket
++) {
2668 if (cb
->stat
[bucket
].nr_samples
)
2669 q
->poll_stat
[bucket
] = cb
->stat
[bucket
];
2673 static unsigned long blk_mq_poll_nsecs(struct request_queue
*q
,
2674 struct blk_mq_hw_ctx
*hctx
,
2677 unsigned long ret
= 0;
2681 * If stats collection isn't on, don't sleep but turn it on for
2684 if (!blk_poll_stats_enable(q
))
2688 * As an optimistic guess, use half of the mean service time
2689 * for this type of request. We can (and should) make this smarter.
2690 * For instance, if the completion latencies are tight, we can
2691 * get closer than just half the mean. This is especially
2692 * important on devices where the completion latencies are longer
2693 * than ~10 usec. We do use the stats for the relevant IO size
2694 * if available which does lead to better estimates.
2696 bucket
= blk_mq_poll_stats_bkt(rq
);
2700 if (q
->poll_stat
[bucket
].nr_samples
)
2701 ret
= (q
->poll_stat
[bucket
].mean
+ 1) / 2;
2706 static bool blk_mq_poll_hybrid_sleep(struct request_queue
*q
,
2707 struct blk_mq_hw_ctx
*hctx
,
2710 struct hrtimer_sleeper hs
;
2711 enum hrtimer_mode mode
;
2715 if (test_bit(REQ_ATOM_POLL_SLEPT
, &rq
->atomic_flags
))
2721 * -1: don't ever hybrid sleep
2722 * 0: use half of prev avg
2723 * >0: use this specific value
2725 if (q
->poll_nsec
== -1)
2727 else if (q
->poll_nsec
> 0)
2728 nsecs
= q
->poll_nsec
;
2730 nsecs
= blk_mq_poll_nsecs(q
, hctx
, rq
);
2735 set_bit(REQ_ATOM_POLL_SLEPT
, &rq
->atomic_flags
);
2738 * This will be replaced with the stats tracking code, using
2739 * 'avg_completion_time / 2' as the pre-sleep target.
2743 mode
= HRTIMER_MODE_REL
;
2744 hrtimer_init_on_stack(&hs
.timer
, CLOCK_MONOTONIC
, mode
);
2745 hrtimer_set_expires(&hs
.timer
, kt
);
2747 hrtimer_init_sleeper(&hs
, current
);
2749 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
2751 set_current_state(TASK_UNINTERRUPTIBLE
);
2752 hrtimer_start_expires(&hs
.timer
, mode
);
2755 hrtimer_cancel(&hs
.timer
);
2756 mode
= HRTIMER_MODE_ABS
;
2757 } while (hs
.task
&& !signal_pending(current
));
2759 __set_current_state(TASK_RUNNING
);
2760 destroy_hrtimer_on_stack(&hs
.timer
);
2764 static bool __blk_mq_poll(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
2766 struct request_queue
*q
= hctx
->queue
;
2770 * If we sleep, have the caller restart the poll loop to reset
2771 * the state. Like for the other success return cases, the
2772 * caller is responsible for checking if the IO completed. If
2773 * the IO isn't complete, we'll get called again and will go
2774 * straight to the busy poll loop.
2776 if (blk_mq_poll_hybrid_sleep(q
, hctx
, rq
))
2779 hctx
->poll_considered
++;
2781 state
= current
->state
;
2782 while (!need_resched()) {
2785 hctx
->poll_invoked
++;
2787 ret
= q
->mq_ops
->poll(hctx
, rq
->tag
);
2789 hctx
->poll_success
++;
2790 set_current_state(TASK_RUNNING
);
2794 if (signal_pending_state(state
, current
))
2795 set_current_state(TASK_RUNNING
);
2797 if (current
->state
== TASK_RUNNING
)
2807 bool blk_mq_poll(struct request_queue
*q
, blk_qc_t cookie
)
2809 struct blk_mq_hw_ctx
*hctx
;
2810 struct blk_plug
*plug
;
2813 if (!q
->mq_ops
|| !q
->mq_ops
->poll
|| !blk_qc_t_valid(cookie
) ||
2814 !test_bit(QUEUE_FLAG_POLL
, &q
->queue_flags
))
2817 plug
= current
->plug
;
2819 blk_flush_plug_list(plug
, false);
2821 hctx
= q
->queue_hw_ctx
[blk_qc_t_to_queue_num(cookie
)];
2822 if (!blk_qc_t_is_internal(cookie
))
2823 rq
= blk_mq_tag_to_rq(hctx
->tags
, blk_qc_t_to_tag(cookie
));
2825 rq
= blk_mq_tag_to_rq(hctx
->sched_tags
, blk_qc_t_to_tag(cookie
));
2827 * With scheduling, if the request has completed, we'll
2828 * get a NULL return here, as we clear the sched tag when
2829 * that happens. The request still remains valid, like always,
2830 * so we should be safe with just the NULL check.
2836 return __blk_mq_poll(hctx
, rq
);
2838 EXPORT_SYMBOL_GPL(blk_mq_poll
);
2840 static int __init
blk_mq_init(void)
2842 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD
, "block/mq:dead", NULL
,
2843 blk_mq_hctx_notify_dead
);
2846 subsys_initcall(blk_mq_init
);