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-tag.h"
37 #include "blk-mq-sched.h"
39 static DEFINE_MUTEX(all_q_mutex
);
40 static LIST_HEAD(all_q_list
);
42 static void blk_mq_poll_stats_start(struct request_queue
*q
);
43 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
);
46 * Check if any of the ctx's have pending work in this hardware queue
48 bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
50 return sbitmap_any_bit_set(&hctx
->ctx_map
) ||
51 !list_empty_careful(&hctx
->dispatch
) ||
52 blk_mq_sched_has_work(hctx
);
56 * Mark this ctx as having pending work in this hardware queue
58 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
59 struct blk_mq_ctx
*ctx
)
61 if (!sbitmap_test_bit(&hctx
->ctx_map
, ctx
->index_hw
))
62 sbitmap_set_bit(&hctx
->ctx_map
, ctx
->index_hw
);
65 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
66 struct blk_mq_ctx
*ctx
)
68 sbitmap_clear_bit(&hctx
->ctx_map
, ctx
->index_hw
);
71 void blk_freeze_queue_start(struct request_queue
*q
)
75 freeze_depth
= atomic_inc_return(&q
->mq_freeze_depth
);
76 if (freeze_depth
== 1) {
77 percpu_ref_kill(&q
->q_usage_counter
);
78 blk_mq_run_hw_queues(q
, false);
81 EXPORT_SYMBOL_GPL(blk_freeze_queue_start
);
83 void blk_mq_freeze_queue_wait(struct request_queue
*q
)
85 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->q_usage_counter
));
87 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait
);
89 int blk_mq_freeze_queue_wait_timeout(struct request_queue
*q
,
90 unsigned long timeout
)
92 return wait_event_timeout(q
->mq_freeze_wq
,
93 percpu_ref_is_zero(&q
->q_usage_counter
),
96 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout
);
99 * Guarantee no request is in use, so we can change any data structure of
100 * the queue afterward.
102 void blk_freeze_queue(struct request_queue
*q
)
105 * In the !blk_mq case we are only calling this to kill the
106 * q_usage_counter, otherwise this increases the freeze depth
107 * and waits for it to return to zero. For this reason there is
108 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
109 * exported to drivers as the only user for unfreeze is blk_mq.
111 blk_freeze_queue_start(q
);
112 blk_mq_freeze_queue_wait(q
);
115 void blk_mq_freeze_queue(struct request_queue
*q
)
118 * ...just an alias to keep freeze and unfreeze actions balanced
119 * in the blk_mq_* namespace
123 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
125 void blk_mq_unfreeze_queue(struct request_queue
*q
)
129 freeze_depth
= atomic_dec_return(&q
->mq_freeze_depth
);
130 WARN_ON_ONCE(freeze_depth
< 0);
132 percpu_ref_reinit(&q
->q_usage_counter
);
133 wake_up_all(&q
->mq_freeze_wq
);
136 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
139 * blk_mq_quiesce_queue() - wait until all ongoing queue_rq calls have finished
142 * Note: this function does not prevent that the struct request end_io()
143 * callback function is invoked. Additionally, it is not prevented that
144 * new queue_rq() calls occur unless the queue has been stopped first.
146 void blk_mq_quiesce_queue(struct request_queue
*q
)
148 struct blk_mq_hw_ctx
*hctx
;
152 blk_mq_stop_hw_queues(q
);
154 queue_for_each_hw_ctx(q
, hctx
, i
) {
155 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
156 synchronize_srcu(&hctx
->queue_rq_srcu
);
163 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue
);
165 void blk_mq_wake_waiters(struct request_queue
*q
)
167 struct blk_mq_hw_ctx
*hctx
;
170 queue_for_each_hw_ctx(q
, hctx
, i
)
171 if (blk_mq_hw_queue_mapped(hctx
))
172 blk_mq_tag_wakeup_all(hctx
->tags
, true);
175 * If we are called because the queue has now been marked as
176 * dying, we need to ensure that processes currently waiting on
177 * the queue are notified as well.
179 wake_up_all(&q
->mq_freeze_wq
);
182 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
184 return blk_mq_has_free_tags(hctx
->tags
);
186 EXPORT_SYMBOL(blk_mq_can_queue
);
188 void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
189 struct request
*rq
, unsigned int op
)
191 INIT_LIST_HEAD(&rq
->queuelist
);
192 /* csd/requeue_work/fifo_time is initialized before use */
196 if (blk_queue_io_stat(q
))
197 rq
->rq_flags
|= RQF_IO_STAT
;
198 /* do not touch atomic flags, it needs atomic ops against the timer */
200 INIT_HLIST_NODE(&rq
->hash
);
201 RB_CLEAR_NODE(&rq
->rb_node
);
204 rq
->start_time
= jiffies
;
205 #ifdef CONFIG_BLK_CGROUP
207 set_start_time_ns(rq
);
208 rq
->io_start_time_ns
= 0;
210 rq
->nr_phys_segments
= 0;
211 #if defined(CONFIG_BLK_DEV_INTEGRITY)
212 rq
->nr_integrity_segments
= 0;
215 /* tag was already set */
219 INIT_LIST_HEAD(&rq
->timeout_list
);
223 rq
->end_io_data
= NULL
;
226 ctx
->rq_dispatched
[op_is_sync(op
)]++;
228 EXPORT_SYMBOL_GPL(blk_mq_rq_ctx_init
);
230 struct request
*__blk_mq_alloc_request(struct blk_mq_alloc_data
*data
,
236 tag
= blk_mq_get_tag(data
);
237 if (tag
!= BLK_MQ_TAG_FAIL
) {
238 struct blk_mq_tags
*tags
= blk_mq_tags_from_data(data
);
240 rq
= tags
->static_rqs
[tag
];
242 if (data
->flags
& BLK_MQ_REQ_INTERNAL
) {
244 rq
->internal_tag
= tag
;
246 if (blk_mq_tag_busy(data
->hctx
)) {
247 rq
->rq_flags
= RQF_MQ_INFLIGHT
;
248 atomic_inc(&data
->hctx
->nr_active
);
251 rq
->internal_tag
= -1;
252 data
->hctx
->tags
->rqs
[rq
->tag
] = rq
;
255 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, op
);
261 EXPORT_SYMBOL_GPL(__blk_mq_alloc_request
);
263 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
,
266 struct blk_mq_alloc_data alloc_data
= { .flags
= flags
};
270 ret
= blk_queue_enter(q
, flags
& BLK_MQ_REQ_NOWAIT
);
274 rq
= blk_mq_sched_get_request(q
, NULL
, rw
, &alloc_data
);
276 blk_mq_put_ctx(alloc_data
.ctx
);
280 return ERR_PTR(-EWOULDBLOCK
);
283 rq
->__sector
= (sector_t
) -1;
284 rq
->bio
= rq
->biotail
= NULL
;
287 EXPORT_SYMBOL(blk_mq_alloc_request
);
289 struct request
*blk_mq_alloc_request_hctx(struct request_queue
*q
, int rw
,
290 unsigned int flags
, unsigned int hctx_idx
)
292 struct blk_mq_alloc_data alloc_data
= { .flags
= flags
};
298 * If the tag allocator sleeps we could get an allocation for a
299 * different hardware context. No need to complicate the low level
300 * allocator for this for the rare use case of a command tied to
303 if (WARN_ON_ONCE(!(flags
& BLK_MQ_REQ_NOWAIT
)))
304 return ERR_PTR(-EINVAL
);
306 if (hctx_idx
>= q
->nr_hw_queues
)
307 return ERR_PTR(-EIO
);
309 ret
= blk_queue_enter(q
, true);
314 * Check if the hardware context is actually mapped to anything.
315 * If not tell the caller that it should skip this queue.
317 alloc_data
.hctx
= q
->queue_hw_ctx
[hctx_idx
];
318 if (!blk_mq_hw_queue_mapped(alloc_data
.hctx
)) {
320 return ERR_PTR(-EXDEV
);
322 cpu
= cpumask_first(alloc_data
.hctx
->cpumask
);
323 alloc_data
.ctx
= __blk_mq_get_ctx(q
, cpu
);
325 rq
= blk_mq_sched_get_request(q
, NULL
, rw
, &alloc_data
);
330 return ERR_PTR(-EWOULDBLOCK
);
334 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx
);
336 void __blk_mq_finish_request(struct blk_mq_hw_ctx
*hctx
, struct blk_mq_ctx
*ctx
,
339 const int sched_tag
= rq
->internal_tag
;
340 struct request_queue
*q
= rq
->q
;
342 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
)
343 atomic_dec(&hctx
->nr_active
);
345 wbt_done(q
->rq_wb
, &rq
->issue_stat
);
348 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
349 clear_bit(REQ_ATOM_POLL_SLEPT
, &rq
->atomic_flags
);
351 blk_mq_put_tag(hctx
, hctx
->tags
, ctx
, rq
->tag
);
353 blk_mq_put_tag(hctx
, hctx
->sched_tags
, ctx
, sched_tag
);
354 blk_mq_sched_restart(hctx
);
358 static void blk_mq_finish_hctx_request(struct blk_mq_hw_ctx
*hctx
,
361 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
363 ctx
->rq_completed
[rq_is_sync(rq
)]++;
364 __blk_mq_finish_request(hctx
, ctx
, rq
);
367 void blk_mq_finish_request(struct request
*rq
)
369 blk_mq_finish_hctx_request(blk_mq_map_queue(rq
->q
, rq
->mq_ctx
->cpu
), rq
);
371 EXPORT_SYMBOL_GPL(blk_mq_finish_request
);
373 void blk_mq_free_request(struct request
*rq
)
375 blk_mq_sched_put_request(rq
);
377 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
379 inline void __blk_mq_end_request(struct request
*rq
, int error
)
381 blk_account_io_done(rq
);
384 wbt_done(rq
->q
->rq_wb
, &rq
->issue_stat
);
385 rq
->end_io(rq
, error
);
387 if (unlikely(blk_bidi_rq(rq
)))
388 blk_mq_free_request(rq
->next_rq
);
389 blk_mq_free_request(rq
);
392 EXPORT_SYMBOL(__blk_mq_end_request
);
394 void blk_mq_end_request(struct request
*rq
, int error
)
396 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
398 __blk_mq_end_request(rq
, error
);
400 EXPORT_SYMBOL(blk_mq_end_request
);
402 static void __blk_mq_complete_request_remote(void *data
)
404 struct request
*rq
= data
;
406 rq
->q
->softirq_done_fn(rq
);
409 static void blk_mq_ipi_complete_request(struct request
*rq
)
411 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
415 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
416 rq
->q
->softirq_done_fn(rq
);
421 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
422 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
424 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
425 rq
->csd
.func
= __blk_mq_complete_request_remote
;
428 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
430 rq
->q
->softirq_done_fn(rq
);
435 static void blk_mq_stat_add(struct request
*rq
)
437 if (rq
->rq_flags
& RQF_STATS
) {
438 blk_mq_poll_stats_start(rq
->q
);
443 static void __blk_mq_complete_request(struct request
*rq
)
445 if (rq
->internal_tag
!= -1)
446 blk_mq_sched_completed_request(rq
);
448 blk_mq_ipi_complete_request(rq
);
452 * blk_mq_complete_request - end I/O on a request
453 * @rq: the request being processed
456 * Ends all I/O on a request. It does not handle partial completions.
457 * The actual completion happens out-of-order, through a IPI handler.
459 void blk_mq_complete_request(struct request
*rq
)
461 struct request_queue
*q
= rq
->q
;
463 if (unlikely(blk_should_fake_timeout(q
)))
465 if (!blk_mark_rq_complete(rq
))
466 __blk_mq_complete_request(rq
);
468 EXPORT_SYMBOL(blk_mq_complete_request
);
470 int blk_mq_request_started(struct request
*rq
)
472 return test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
474 EXPORT_SYMBOL_GPL(blk_mq_request_started
);
476 void blk_mq_start_request(struct request
*rq
)
478 struct request_queue
*q
= rq
->q
;
480 blk_mq_sched_started_request(rq
);
482 trace_block_rq_issue(q
, rq
);
484 if (test_bit(QUEUE_FLAG_STATS
, &q
->queue_flags
)) {
485 blk_stat_set_issue(&rq
->issue_stat
, blk_rq_sectors(rq
));
486 rq
->rq_flags
|= RQF_STATS
;
487 wbt_issue(q
->rq_wb
, &rq
->issue_stat
);
493 * Ensure that ->deadline is visible before set the started
494 * flag and clear the completed flag.
496 smp_mb__before_atomic();
499 * Mark us as started and clear complete. Complete might have been
500 * set if requeue raced with timeout, which then marked it as
501 * complete. So be sure to clear complete again when we start
502 * the request, otherwise we'll ignore the completion event.
504 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
505 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
506 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
507 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
509 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
511 * Make sure space for the drain appears. We know we can do
512 * this because max_hw_segments has been adjusted to be one
513 * fewer than the device can handle.
515 rq
->nr_phys_segments
++;
518 EXPORT_SYMBOL(blk_mq_start_request
);
521 * When we reach here because queue is busy, REQ_ATOM_COMPLETE
522 * flag isn't set yet, so there may be race with timeout handler,
523 * but given rq->deadline is just set in .queue_rq() under
524 * this situation, the race won't be possible in reality because
525 * rq->timeout should be set as big enough to cover the window
526 * between blk_mq_start_request() called from .queue_rq() and
527 * clearing REQ_ATOM_STARTED here.
529 static void __blk_mq_requeue_request(struct request
*rq
)
531 struct request_queue
*q
= rq
->q
;
533 trace_block_rq_requeue(q
, rq
);
534 wbt_requeue(q
->rq_wb
, &rq
->issue_stat
);
535 blk_mq_sched_requeue_request(rq
);
537 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
538 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
539 rq
->nr_phys_segments
--;
543 void blk_mq_requeue_request(struct request
*rq
, bool kick_requeue_list
)
545 __blk_mq_requeue_request(rq
);
547 BUG_ON(blk_queued_rq(rq
));
548 blk_mq_add_to_requeue_list(rq
, true, kick_requeue_list
);
550 EXPORT_SYMBOL(blk_mq_requeue_request
);
552 static void blk_mq_requeue_work(struct work_struct
*work
)
554 struct request_queue
*q
=
555 container_of(work
, struct request_queue
, requeue_work
.work
);
557 struct request
*rq
, *next
;
560 spin_lock_irqsave(&q
->requeue_lock
, flags
);
561 list_splice_init(&q
->requeue_list
, &rq_list
);
562 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
564 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
565 if (!(rq
->rq_flags
& RQF_SOFTBARRIER
))
568 rq
->rq_flags
&= ~RQF_SOFTBARRIER
;
569 list_del_init(&rq
->queuelist
);
570 blk_mq_sched_insert_request(rq
, true, false, false, true);
573 while (!list_empty(&rq_list
)) {
574 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
575 list_del_init(&rq
->queuelist
);
576 blk_mq_sched_insert_request(rq
, false, false, false, true);
579 blk_mq_run_hw_queues(q
, false);
582 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
,
583 bool kick_requeue_list
)
585 struct request_queue
*q
= rq
->q
;
589 * We abuse this flag that is otherwise used by the I/O scheduler to
590 * request head insertation from the workqueue.
592 BUG_ON(rq
->rq_flags
& RQF_SOFTBARRIER
);
594 spin_lock_irqsave(&q
->requeue_lock
, flags
);
596 rq
->rq_flags
|= RQF_SOFTBARRIER
;
597 list_add(&rq
->queuelist
, &q
->requeue_list
);
599 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
601 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
603 if (kick_requeue_list
)
604 blk_mq_kick_requeue_list(q
);
606 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
608 void blk_mq_kick_requeue_list(struct request_queue
*q
)
610 kblockd_schedule_delayed_work(&q
->requeue_work
, 0);
612 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
614 void blk_mq_delay_kick_requeue_list(struct request_queue
*q
,
617 kblockd_schedule_delayed_work(&q
->requeue_work
,
618 msecs_to_jiffies(msecs
));
620 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list
);
622 void blk_mq_abort_requeue_list(struct request_queue
*q
)
627 spin_lock_irqsave(&q
->requeue_lock
, flags
);
628 list_splice_init(&q
->requeue_list
, &rq_list
);
629 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
631 while (!list_empty(&rq_list
)) {
634 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
635 list_del_init(&rq
->queuelist
);
637 blk_mq_end_request(rq
, rq
->errors
);
640 EXPORT_SYMBOL(blk_mq_abort_requeue_list
);
642 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
644 if (tag
< tags
->nr_tags
) {
645 prefetch(tags
->rqs
[tag
]);
646 return tags
->rqs
[tag
];
651 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
653 struct blk_mq_timeout_data
{
655 unsigned int next_set
;
658 void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
660 const struct blk_mq_ops
*ops
= req
->q
->mq_ops
;
661 enum blk_eh_timer_return ret
= BLK_EH_RESET_TIMER
;
664 * We know that complete is set at this point. If STARTED isn't set
665 * anymore, then the request isn't active and the "timeout" should
666 * just be ignored. This can happen due to the bitflag ordering.
667 * Timeout first checks if STARTED is set, and if it is, assumes
668 * the request is active. But if we race with completion, then
669 * both flags will get cleared. So check here again, and ignore
670 * a timeout event with a request that isn't active.
672 if (!test_bit(REQ_ATOM_STARTED
, &req
->atomic_flags
))
676 ret
= ops
->timeout(req
, reserved
);
680 __blk_mq_complete_request(req
);
682 case BLK_EH_RESET_TIMER
:
684 blk_clear_rq_complete(req
);
686 case BLK_EH_NOT_HANDLED
:
689 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
694 static void blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
695 struct request
*rq
, void *priv
, bool reserved
)
697 struct blk_mq_timeout_data
*data
= priv
;
699 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
703 * The rq being checked may have been freed and reallocated
704 * out already here, we avoid this race by checking rq->deadline
705 * and REQ_ATOM_COMPLETE flag together:
707 * - if rq->deadline is observed as new value because of
708 * reusing, the rq won't be timed out because of timing.
709 * - if rq->deadline is observed as previous value,
710 * REQ_ATOM_COMPLETE flag won't be cleared in reuse path
711 * because we put a barrier between setting rq->deadline
712 * and clearing the flag in blk_mq_start_request(), so
713 * this rq won't be timed out too.
715 if (time_after_eq(jiffies
, rq
->deadline
)) {
716 if (!blk_mark_rq_complete(rq
))
717 blk_mq_rq_timed_out(rq
, reserved
);
718 } else if (!data
->next_set
|| time_after(data
->next
, rq
->deadline
)) {
719 data
->next
= rq
->deadline
;
724 static void blk_mq_timeout_work(struct work_struct
*work
)
726 struct request_queue
*q
=
727 container_of(work
, struct request_queue
, timeout_work
);
728 struct blk_mq_timeout_data data
= {
734 /* A deadlock might occur if a request is stuck requiring a
735 * timeout at the same time a queue freeze is waiting
736 * completion, since the timeout code would not be able to
737 * acquire the queue reference here.
739 * That's why we don't use blk_queue_enter here; instead, we use
740 * percpu_ref_tryget directly, because we need to be able to
741 * obtain a reference even in the short window between the queue
742 * starting to freeze, by dropping the first reference in
743 * blk_freeze_queue_start, and the moment the last request is
744 * consumed, marked by the instant q_usage_counter reaches
747 if (!percpu_ref_tryget(&q
->q_usage_counter
))
750 blk_mq_queue_tag_busy_iter(q
, blk_mq_check_expired
, &data
);
753 data
.next
= blk_rq_timeout(round_jiffies_up(data
.next
));
754 mod_timer(&q
->timeout
, data
.next
);
756 struct blk_mq_hw_ctx
*hctx
;
758 queue_for_each_hw_ctx(q
, hctx
, i
) {
759 /* the hctx may be unmapped, so check it here */
760 if (blk_mq_hw_queue_mapped(hctx
))
761 blk_mq_tag_idle(hctx
);
768 * Reverse check our software queue for entries that we could potentially
769 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
770 * too much time checking for merges.
772 static bool blk_mq_attempt_merge(struct request_queue
*q
,
773 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
778 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
784 if (!blk_rq_merge_ok(rq
, bio
))
787 switch (blk_try_merge(rq
, bio
)) {
788 case ELEVATOR_BACK_MERGE
:
789 if (blk_mq_sched_allow_merge(q
, rq
, bio
))
790 merged
= bio_attempt_back_merge(q
, rq
, bio
);
792 case ELEVATOR_FRONT_MERGE
:
793 if (blk_mq_sched_allow_merge(q
, rq
, bio
))
794 merged
= bio_attempt_front_merge(q
, rq
, bio
);
796 case ELEVATOR_DISCARD_MERGE
:
797 merged
= bio_attempt_discard_merge(q
, rq
, bio
);
811 struct flush_busy_ctx_data
{
812 struct blk_mq_hw_ctx
*hctx
;
813 struct list_head
*list
;
816 static bool flush_busy_ctx(struct sbitmap
*sb
, unsigned int bitnr
, void *data
)
818 struct flush_busy_ctx_data
*flush_data
= data
;
819 struct blk_mq_hw_ctx
*hctx
= flush_data
->hctx
;
820 struct blk_mq_ctx
*ctx
= hctx
->ctxs
[bitnr
];
822 sbitmap_clear_bit(sb
, bitnr
);
823 spin_lock(&ctx
->lock
);
824 list_splice_tail_init(&ctx
->rq_list
, flush_data
->list
);
825 spin_unlock(&ctx
->lock
);
830 * Process software queues that have been marked busy, splicing them
831 * to the for-dispatch
833 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
835 struct flush_busy_ctx_data data
= {
840 sbitmap_for_each_set(&hctx
->ctx_map
, flush_busy_ctx
, &data
);
842 EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs
);
844 static inline unsigned int queued_to_index(unsigned int queued
)
849 return min(BLK_MQ_MAX_DISPATCH_ORDER
- 1, ilog2(queued
) + 1);
852 bool blk_mq_get_driver_tag(struct request
*rq
, struct blk_mq_hw_ctx
**hctx
,
855 struct blk_mq_alloc_data data
= {
857 .hctx
= blk_mq_map_queue(rq
->q
, rq
->mq_ctx
->cpu
),
858 .flags
= wait
? 0 : BLK_MQ_REQ_NOWAIT
,
864 if (blk_mq_tag_is_reserved(data
.hctx
->sched_tags
, rq
->internal_tag
))
865 data
.flags
|= BLK_MQ_REQ_RESERVED
;
867 rq
->tag
= blk_mq_get_tag(&data
);
869 if (blk_mq_tag_busy(data
.hctx
)) {
870 rq
->rq_flags
|= RQF_MQ_INFLIGHT
;
871 atomic_inc(&data
.hctx
->nr_active
);
873 data
.hctx
->tags
->rqs
[rq
->tag
] = rq
;
879 return rq
->tag
!= -1;
882 static void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx
*hctx
,
885 blk_mq_put_tag(hctx
, hctx
->tags
, rq
->mq_ctx
, rq
->tag
);
888 if (rq
->rq_flags
& RQF_MQ_INFLIGHT
) {
889 rq
->rq_flags
&= ~RQF_MQ_INFLIGHT
;
890 atomic_dec(&hctx
->nr_active
);
894 static void blk_mq_put_driver_tag_hctx(struct blk_mq_hw_ctx
*hctx
,
897 if (rq
->tag
== -1 || rq
->internal_tag
== -1)
900 __blk_mq_put_driver_tag(hctx
, rq
);
903 static void blk_mq_put_driver_tag(struct request
*rq
)
905 struct blk_mq_hw_ctx
*hctx
;
907 if (rq
->tag
== -1 || rq
->internal_tag
== -1)
910 hctx
= blk_mq_map_queue(rq
->q
, rq
->mq_ctx
->cpu
);
911 __blk_mq_put_driver_tag(hctx
, rq
);
915 * If we fail getting a driver tag because all the driver tags are already
916 * assigned and on the dispatch list, BUT the first entry does not have a
917 * tag, then we could deadlock. For that case, move entries with assigned
918 * driver tags to the front, leaving the set of tagged requests in the
919 * same order, and the untagged set in the same order.
921 static bool reorder_tags_to_front(struct list_head
*list
)
923 struct request
*rq
, *tmp
, *first
= NULL
;
925 list_for_each_entry_safe_reverse(rq
, tmp
, list
, queuelist
) {
929 list_move(&rq
->queuelist
, list
);
935 return first
!= NULL
;
938 static int blk_mq_dispatch_wake(wait_queue_t
*wait
, unsigned mode
, int flags
,
941 struct blk_mq_hw_ctx
*hctx
;
943 hctx
= container_of(wait
, struct blk_mq_hw_ctx
, dispatch_wait
);
945 list_del(&wait
->task_list
);
946 clear_bit_unlock(BLK_MQ_S_TAG_WAITING
, &hctx
->state
);
947 blk_mq_run_hw_queue(hctx
, true);
951 static bool blk_mq_dispatch_wait_add(struct blk_mq_hw_ctx
*hctx
)
953 struct sbq_wait_state
*ws
;
956 * The TAG_WAITING bit serves as a lock protecting hctx->dispatch_wait.
957 * The thread which wins the race to grab this bit adds the hardware
958 * queue to the wait queue.
960 if (test_bit(BLK_MQ_S_TAG_WAITING
, &hctx
->state
) ||
961 test_and_set_bit_lock(BLK_MQ_S_TAG_WAITING
, &hctx
->state
))
964 init_waitqueue_func_entry(&hctx
->dispatch_wait
, blk_mq_dispatch_wake
);
965 ws
= bt_wait_ptr(&hctx
->tags
->bitmap_tags
, hctx
);
968 * As soon as this returns, it's no longer safe to fiddle with
969 * hctx->dispatch_wait, since a completion can wake up the wait queue
970 * and unlock the bit.
972 add_wait_queue(&ws
->wait
, &hctx
->dispatch_wait
);
976 bool blk_mq_dispatch_rq_list(struct request_queue
*q
, struct list_head
*list
)
978 struct blk_mq_hw_ctx
*hctx
;
980 int errors
, queued
, ret
= BLK_MQ_RQ_QUEUE_OK
;
982 if (list_empty(list
))
986 * Now process all the entries, sending them to the driver.
990 struct blk_mq_queue_data bd
;
992 rq
= list_first_entry(list
, struct request
, queuelist
);
993 if (!blk_mq_get_driver_tag(rq
, &hctx
, false)) {
994 if (!queued
&& reorder_tags_to_front(list
))
998 * The initial allocation attempt failed, so we need to
999 * rerun the hardware queue when a tag is freed.
1001 if (!blk_mq_dispatch_wait_add(hctx
))
1005 * It's possible that a tag was freed in the window
1006 * between the allocation failure and adding the
1007 * hardware queue to the wait queue.
1009 if (!blk_mq_get_driver_tag(rq
, &hctx
, false))
1013 list_del_init(&rq
->queuelist
);
1018 * Flag last if we have no more requests, or if we have more
1019 * but can't assign a driver tag to it.
1021 if (list_empty(list
))
1024 struct request
*nxt
;
1026 nxt
= list_first_entry(list
, struct request
, queuelist
);
1027 bd
.last
= !blk_mq_get_driver_tag(nxt
, NULL
, false);
1030 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1032 case BLK_MQ_RQ_QUEUE_OK
:
1035 case BLK_MQ_RQ_QUEUE_BUSY
:
1036 blk_mq_put_driver_tag_hctx(hctx
, rq
);
1037 list_add(&rq
->queuelist
, list
);
1038 __blk_mq_requeue_request(rq
);
1041 pr_err("blk-mq: bad return on queue: %d\n", ret
);
1042 case BLK_MQ_RQ_QUEUE_ERROR
:
1045 blk_mq_end_request(rq
, rq
->errors
);
1049 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
1051 } while (!list_empty(list
));
1053 hctx
->dispatched
[queued_to_index(queued
)]++;
1056 * Any items that need requeuing? Stuff them into hctx->dispatch,
1057 * that is where we will continue on next queue run.
1059 if (!list_empty(list
)) {
1061 * If an I/O scheduler has been configured and we got a driver
1062 * tag for the next request already, free it again.
1064 rq
= list_first_entry(list
, struct request
, queuelist
);
1065 blk_mq_put_driver_tag(rq
);
1067 spin_lock(&hctx
->lock
);
1068 list_splice_init(list
, &hctx
->dispatch
);
1069 spin_unlock(&hctx
->lock
);
1072 * If SCHED_RESTART was set by the caller of this function and
1073 * it is no longer set that means that it was cleared by another
1074 * thread and hence that a queue rerun is needed.
1076 * If TAG_WAITING is set that means that an I/O scheduler has
1077 * been configured and another thread is waiting for a driver
1078 * tag. To guarantee fairness, do not rerun this hardware queue
1079 * but let the other thread grab the driver tag.
1081 * If no I/O scheduler has been configured it is possible that
1082 * the hardware queue got stopped and restarted before requests
1083 * were pushed back onto the dispatch list. Rerun the queue to
1084 * avoid starvation. Notes:
1085 * - blk_mq_run_hw_queue() checks whether or not a queue has
1086 * been stopped before rerunning a queue.
1087 * - Some but not all block drivers stop a queue before
1088 * returning BLK_MQ_RQ_QUEUE_BUSY. Two exceptions are scsi-mq
1091 if (!blk_mq_sched_needs_restart(hctx
) &&
1092 !test_bit(BLK_MQ_S_TAG_WAITING
, &hctx
->state
))
1093 blk_mq_run_hw_queue(hctx
, true);
1096 return (queued
+ errors
) != 0;
1099 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1103 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
) &&
1104 cpu_online(hctx
->next_cpu
));
1106 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1108 blk_mq_sched_dispatch_requests(hctx
);
1113 srcu_idx
= srcu_read_lock(&hctx
->queue_rq_srcu
);
1114 blk_mq_sched_dispatch_requests(hctx
);
1115 srcu_read_unlock(&hctx
->queue_rq_srcu
, srcu_idx
);
1120 * It'd be great if the workqueue API had a way to pass
1121 * in a mask and had some smarts for more clever placement.
1122 * For now we just round-robin here, switching for every
1123 * BLK_MQ_CPU_WORK_BATCH queued items.
1125 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
1127 if (hctx
->queue
->nr_hw_queues
== 1)
1128 return WORK_CPU_UNBOUND
;
1130 if (--hctx
->next_cpu_batch
<= 0) {
1133 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
1134 if (next_cpu
>= nr_cpu_ids
)
1135 next_cpu
= cpumask_first(hctx
->cpumask
);
1137 hctx
->next_cpu
= next_cpu
;
1138 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1141 return hctx
->next_cpu
;
1144 static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
,
1145 unsigned long msecs
)
1147 if (unlikely(blk_mq_hctx_stopped(hctx
) ||
1148 !blk_mq_hw_queue_mapped(hctx
)))
1151 if (!async
&& !(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1152 int cpu
= get_cpu();
1153 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
1154 __blk_mq_run_hw_queue(hctx
);
1163 kblockd_schedule_work_on(blk_mq_hctx_next_cpu(hctx
),
1166 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
1167 &hctx
->delayed_run_work
,
1168 msecs_to_jiffies(msecs
));
1171 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1173 __blk_mq_delay_run_hw_queue(hctx
, true, msecs
);
1175 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue
);
1177 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1179 __blk_mq_delay_run_hw_queue(hctx
, async
, 0);
1181 EXPORT_SYMBOL(blk_mq_run_hw_queue
);
1183 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
1185 struct blk_mq_hw_ctx
*hctx
;
1188 queue_for_each_hw_ctx(q
, hctx
, i
) {
1189 if (!blk_mq_hctx_has_pending(hctx
) ||
1190 blk_mq_hctx_stopped(hctx
))
1193 blk_mq_run_hw_queue(hctx
, async
);
1196 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
1199 * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
1200 * @q: request queue.
1202 * The caller is responsible for serializing this function against
1203 * blk_mq_{start,stop}_hw_queue().
1205 bool blk_mq_queue_stopped(struct request_queue
*q
)
1207 struct blk_mq_hw_ctx
*hctx
;
1210 queue_for_each_hw_ctx(q
, hctx
, i
)
1211 if (blk_mq_hctx_stopped(hctx
))
1216 EXPORT_SYMBOL(blk_mq_queue_stopped
);
1218 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1220 cancel_work(&hctx
->run_work
);
1221 cancel_delayed_work(&hctx
->delay_work
);
1222 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1224 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
1226 void blk_mq_stop_hw_queues(struct request_queue
*q
)
1228 struct blk_mq_hw_ctx
*hctx
;
1231 queue_for_each_hw_ctx(q
, hctx
, i
)
1232 blk_mq_stop_hw_queue(hctx
);
1234 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
1236 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
1238 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1240 blk_mq_run_hw_queue(hctx
, false);
1242 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
1244 void blk_mq_start_hw_queues(struct request_queue
*q
)
1246 struct blk_mq_hw_ctx
*hctx
;
1249 queue_for_each_hw_ctx(q
, hctx
, i
)
1250 blk_mq_start_hw_queue(hctx
);
1252 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
1254 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
1256 if (!blk_mq_hctx_stopped(hctx
))
1259 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
1260 blk_mq_run_hw_queue(hctx
, async
);
1262 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue
);
1264 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
1266 struct blk_mq_hw_ctx
*hctx
;
1269 queue_for_each_hw_ctx(q
, hctx
, i
)
1270 blk_mq_start_stopped_hw_queue(hctx
, async
);
1272 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
1274 static void blk_mq_run_work_fn(struct work_struct
*work
)
1276 struct blk_mq_hw_ctx
*hctx
;
1278 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
);
1280 __blk_mq_run_hw_queue(hctx
);
1283 static void blk_mq_delayed_run_work_fn(struct work_struct
*work
)
1285 struct blk_mq_hw_ctx
*hctx
;
1287 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delayed_run_work
.work
);
1289 __blk_mq_run_hw_queue(hctx
);
1292 static void blk_mq_delay_work_fn(struct work_struct
*work
)
1294 struct blk_mq_hw_ctx
*hctx
;
1296 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
1298 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
1299 __blk_mq_run_hw_queue(hctx
);
1302 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1304 if (unlikely(!blk_mq_hw_queue_mapped(hctx
)))
1307 blk_mq_stop_hw_queue(hctx
);
1308 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
1309 &hctx
->delay_work
, msecs_to_jiffies(msecs
));
1311 EXPORT_SYMBOL(blk_mq_delay_queue
);
1313 static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx
*hctx
,
1317 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1319 trace_block_rq_insert(hctx
->queue
, rq
);
1322 list_add(&rq
->queuelist
, &ctx
->rq_list
);
1324 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
1327 void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
,
1330 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1332 __blk_mq_insert_req_list(hctx
, rq
, at_head
);
1333 blk_mq_hctx_mark_pending(hctx
, ctx
);
1336 void blk_mq_insert_requests(struct blk_mq_hw_ctx
*hctx
, struct blk_mq_ctx
*ctx
,
1337 struct list_head
*list
)
1341 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1344 spin_lock(&ctx
->lock
);
1345 while (!list_empty(list
)) {
1348 rq
= list_first_entry(list
, struct request
, queuelist
);
1349 BUG_ON(rq
->mq_ctx
!= ctx
);
1350 list_del_init(&rq
->queuelist
);
1351 __blk_mq_insert_req_list(hctx
, rq
, false);
1353 blk_mq_hctx_mark_pending(hctx
, ctx
);
1354 spin_unlock(&ctx
->lock
);
1357 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1359 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1360 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1362 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1363 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1364 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1367 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1369 struct blk_mq_ctx
*this_ctx
;
1370 struct request_queue
*this_q
;
1373 LIST_HEAD(ctx_list
);
1376 list_splice_init(&plug
->mq_list
, &list
);
1378 list_sort(NULL
, &list
, plug_ctx_cmp
);
1384 while (!list_empty(&list
)) {
1385 rq
= list_entry_rq(list
.next
);
1386 list_del_init(&rq
->queuelist
);
1388 if (rq
->mq_ctx
!= this_ctx
) {
1390 trace_block_unplug(this_q
, depth
, from_schedule
);
1391 blk_mq_sched_insert_requests(this_q
, this_ctx
,
1396 this_ctx
= rq
->mq_ctx
;
1402 list_add_tail(&rq
->queuelist
, &ctx_list
);
1406 * If 'this_ctx' is set, we know we have entries to complete
1407 * on 'ctx_list'. Do those.
1410 trace_block_unplug(this_q
, depth
, from_schedule
);
1411 blk_mq_sched_insert_requests(this_q
, this_ctx
, &ctx_list
,
1416 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1418 blk_init_request_from_bio(rq
, bio
);
1420 blk_account_io_start(rq
, true);
1423 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1425 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1426 !blk_queue_nomerges(hctx
->queue
);
1429 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1430 struct blk_mq_ctx
*ctx
,
1431 struct request
*rq
, struct bio
*bio
)
1433 if (!hctx_allow_merges(hctx
) || !bio_mergeable(bio
)) {
1434 blk_mq_bio_to_request(rq
, bio
);
1435 spin_lock(&ctx
->lock
);
1437 __blk_mq_insert_request(hctx
, rq
, false);
1438 spin_unlock(&ctx
->lock
);
1441 struct request_queue
*q
= hctx
->queue
;
1443 spin_lock(&ctx
->lock
);
1444 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1445 blk_mq_bio_to_request(rq
, bio
);
1449 spin_unlock(&ctx
->lock
);
1450 __blk_mq_finish_request(hctx
, ctx
, rq
);
1455 static blk_qc_t
request_to_qc_t(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
1458 return blk_tag_to_qc_t(rq
->tag
, hctx
->queue_num
, false);
1460 return blk_tag_to_qc_t(rq
->internal_tag
, hctx
->queue_num
, true);
1463 static void __blk_mq_try_issue_directly(struct request
*rq
, blk_qc_t
*cookie
,
1466 struct request_queue
*q
= rq
->q
;
1467 struct blk_mq_queue_data bd
= {
1471 struct blk_mq_hw_ctx
*hctx
;
1472 blk_qc_t new_cookie
;
1478 if (!blk_mq_get_driver_tag(rq
, &hctx
, false))
1481 new_cookie
= request_to_qc_t(hctx
, rq
);
1484 * For OK queue, we are done. For error, kill it. Any other
1485 * error (busy), just add it to our list as we previously
1488 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1489 if (ret
== BLK_MQ_RQ_QUEUE_OK
) {
1490 *cookie
= new_cookie
;
1494 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1495 *cookie
= BLK_QC_T_NONE
;
1497 blk_mq_end_request(rq
, rq
->errors
);
1501 __blk_mq_requeue_request(rq
);
1503 blk_mq_sched_insert_request(rq
, false, true, false, may_sleep
);
1506 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx
*hctx
,
1507 struct request
*rq
, blk_qc_t
*cookie
)
1509 if (!(hctx
->flags
& BLK_MQ_F_BLOCKING
)) {
1511 __blk_mq_try_issue_directly(rq
, cookie
, false);
1514 unsigned int srcu_idx
;
1518 srcu_idx
= srcu_read_lock(&hctx
->queue_rq_srcu
);
1519 __blk_mq_try_issue_directly(rq
, cookie
, true);
1520 srcu_read_unlock(&hctx
->queue_rq_srcu
, srcu_idx
);
1524 static blk_qc_t
blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1526 const int is_sync
= op_is_sync(bio
->bi_opf
);
1527 const int is_flush_fua
= op_is_flush(bio
->bi_opf
);
1528 struct blk_mq_alloc_data data
= { .flags
= 0 };
1530 unsigned int request_count
= 0;
1531 struct blk_plug
*plug
;
1532 struct request
*same_queue_rq
= NULL
;
1534 unsigned int wb_acct
;
1536 blk_queue_bounce(q
, &bio
);
1538 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1540 return BLK_QC_T_NONE
;
1543 blk_queue_split(q
, &bio
, q
->bio_split
);
1545 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
1546 blk_attempt_plug_merge(q
, bio
, &request_count
, &same_queue_rq
))
1547 return BLK_QC_T_NONE
;
1549 if (blk_mq_sched_bio_merge(q
, bio
))
1550 return BLK_QC_T_NONE
;
1552 wb_acct
= wbt_wait(q
->rq_wb
, bio
, NULL
);
1554 trace_block_getrq(q
, bio
, bio
->bi_opf
);
1556 rq
= blk_mq_sched_get_request(q
, bio
, bio
->bi_opf
, &data
);
1557 if (unlikely(!rq
)) {
1558 __wbt_done(q
->rq_wb
, wb_acct
);
1559 return BLK_QC_T_NONE
;
1562 wbt_track(&rq
->issue_stat
, wb_acct
);
1564 cookie
= request_to_qc_t(data
.hctx
, rq
);
1566 plug
= current
->plug
;
1567 if (unlikely(is_flush_fua
)) {
1568 blk_mq_bio_to_request(rq
, bio
);
1570 blk_mq_sched_insert_request(rq
, false, true, true,
1573 blk_insert_flush(rq
);
1574 blk_mq_run_hw_queue(data
.hctx
, true);
1576 } else if (plug
&& q
->nr_hw_queues
== 1) {
1577 struct request
*last
= NULL
;
1579 blk_mq_bio_to_request(rq
, bio
);
1582 * @request_count may become stale because of schedule
1583 * out, so check the list again.
1585 if (list_empty(&plug
->mq_list
))
1587 else if (blk_queue_nomerges(q
))
1588 request_count
= blk_plug_queued_count(q
);
1591 trace_block_plug(q
);
1593 last
= list_entry_rq(plug
->mq_list
.prev
);
1595 if (request_count
>= BLK_MAX_REQUEST_COUNT
|| (last
&&
1596 blk_rq_bytes(last
) >= BLK_PLUG_FLUSH_SIZE
)) {
1597 blk_flush_plug_list(plug
, false);
1598 trace_block_plug(q
);
1601 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1602 } else if (plug
&& !blk_queue_nomerges(q
)) {
1603 blk_mq_bio_to_request(rq
, bio
);
1606 * We do limited plugging. If the bio can be merged, do that.
1607 * Otherwise the existing request in the plug list will be
1608 * issued. So the plug list will have one request at most
1609 * The plug list might get flushed before this. If that happens,
1610 * the plug list is empty, and same_queue_rq is invalid.
1612 if (list_empty(&plug
->mq_list
))
1613 same_queue_rq
= NULL
;
1615 list_del_init(&same_queue_rq
->queuelist
);
1616 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1618 blk_mq_put_ctx(data
.ctx
);
1621 blk_mq_try_issue_directly(data
.hctx
, same_queue_rq
,
1625 } else if (q
->nr_hw_queues
> 1 && is_sync
) {
1626 blk_mq_put_ctx(data
.ctx
);
1627 blk_mq_bio_to_request(rq
, bio
);
1628 blk_mq_try_issue_directly(data
.hctx
, rq
, &cookie
);
1630 } else if (q
->elevator
) {
1631 blk_mq_bio_to_request(rq
, bio
);
1632 blk_mq_sched_insert_request(rq
, false, true, true, true);
1633 } else if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
))
1634 blk_mq_run_hw_queue(data
.hctx
, true);
1636 blk_mq_put_ctx(data
.ctx
);
1640 void blk_mq_free_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
1641 unsigned int hctx_idx
)
1645 if (tags
->rqs
&& set
->ops
->exit_request
) {
1648 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1649 struct request
*rq
= tags
->static_rqs
[i
];
1653 set
->ops
->exit_request(set
->driver_data
, rq
,
1655 tags
->static_rqs
[i
] = NULL
;
1659 while (!list_empty(&tags
->page_list
)) {
1660 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1661 list_del_init(&page
->lru
);
1663 * Remove kmemleak object previously allocated in
1664 * blk_mq_init_rq_map().
1666 kmemleak_free(page_address(page
));
1667 __free_pages(page
, page
->private);
1671 void blk_mq_free_rq_map(struct blk_mq_tags
*tags
)
1675 kfree(tags
->static_rqs
);
1676 tags
->static_rqs
= NULL
;
1678 blk_mq_free_tags(tags
);
1681 struct blk_mq_tags
*blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
,
1682 unsigned int hctx_idx
,
1683 unsigned int nr_tags
,
1684 unsigned int reserved_tags
)
1686 struct blk_mq_tags
*tags
;
1689 node
= blk_mq_hw_queue_to_node(set
->mq_map
, hctx_idx
);
1690 if (node
== NUMA_NO_NODE
)
1691 node
= set
->numa_node
;
1693 tags
= blk_mq_init_tags(nr_tags
, reserved_tags
, node
,
1694 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
1698 tags
->rqs
= kzalloc_node(nr_tags
* sizeof(struct request
*),
1699 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
1702 blk_mq_free_tags(tags
);
1706 tags
->static_rqs
= kzalloc_node(nr_tags
* sizeof(struct request
*),
1707 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
,
1709 if (!tags
->static_rqs
) {
1711 blk_mq_free_tags(tags
);
1718 static size_t order_to_size(unsigned int order
)
1720 return (size_t)PAGE_SIZE
<< order
;
1723 int blk_mq_alloc_rqs(struct blk_mq_tag_set
*set
, struct blk_mq_tags
*tags
,
1724 unsigned int hctx_idx
, unsigned int depth
)
1726 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1727 size_t rq_size
, left
;
1730 node
= blk_mq_hw_queue_to_node(set
->mq_map
, hctx_idx
);
1731 if (node
== NUMA_NO_NODE
)
1732 node
= set
->numa_node
;
1734 INIT_LIST_HEAD(&tags
->page_list
);
1737 * rq_size is the size of the request plus driver payload, rounded
1738 * to the cacheline size
1740 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1742 left
= rq_size
* depth
;
1744 for (i
= 0; i
< depth
; ) {
1745 int this_order
= max_order
;
1750 while (this_order
&& left
< order_to_size(this_order
- 1))
1754 page
= alloc_pages_node(node
,
1755 GFP_NOIO
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
1761 if (order_to_size(this_order
) < rq_size
)
1768 page
->private = this_order
;
1769 list_add_tail(&page
->lru
, &tags
->page_list
);
1771 p
= page_address(page
);
1773 * Allow kmemleak to scan these pages as they contain pointers
1774 * to additional allocations like via ops->init_request().
1776 kmemleak_alloc(p
, order_to_size(this_order
), 1, GFP_NOIO
);
1777 entries_per_page
= order_to_size(this_order
) / rq_size
;
1778 to_do
= min(entries_per_page
, depth
- i
);
1779 left
-= to_do
* rq_size
;
1780 for (j
= 0; j
< to_do
; j
++) {
1781 struct request
*rq
= p
;
1783 tags
->static_rqs
[i
] = rq
;
1784 if (set
->ops
->init_request
) {
1785 if (set
->ops
->init_request(set
->driver_data
,
1788 tags
->static_rqs
[i
] = NULL
;
1800 blk_mq_free_rqs(set
, tags
, hctx_idx
);
1805 * 'cpu' is going away. splice any existing rq_list entries from this
1806 * software queue to the hw queue dispatch list, and ensure that it
1809 static int blk_mq_hctx_notify_dead(unsigned int cpu
, struct hlist_node
*node
)
1811 struct blk_mq_hw_ctx
*hctx
;
1812 struct blk_mq_ctx
*ctx
;
1815 hctx
= hlist_entry_safe(node
, struct blk_mq_hw_ctx
, cpuhp_dead
);
1816 ctx
= __blk_mq_get_ctx(hctx
->queue
, cpu
);
1818 spin_lock(&ctx
->lock
);
1819 if (!list_empty(&ctx
->rq_list
)) {
1820 list_splice_init(&ctx
->rq_list
, &tmp
);
1821 blk_mq_hctx_clear_pending(hctx
, ctx
);
1823 spin_unlock(&ctx
->lock
);
1825 if (list_empty(&tmp
))
1828 spin_lock(&hctx
->lock
);
1829 list_splice_tail_init(&tmp
, &hctx
->dispatch
);
1830 spin_unlock(&hctx
->lock
);
1832 blk_mq_run_hw_queue(hctx
, true);
1836 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx
*hctx
)
1838 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD
,
1842 /* hctx->ctxs will be freed in queue's release handler */
1843 static void blk_mq_exit_hctx(struct request_queue
*q
,
1844 struct blk_mq_tag_set
*set
,
1845 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1847 unsigned flush_start_tag
= set
->queue_depth
;
1849 blk_mq_tag_idle(hctx
);
1851 if (set
->ops
->exit_request
)
1852 set
->ops
->exit_request(set
->driver_data
,
1853 hctx
->fq
->flush_rq
, hctx_idx
,
1854 flush_start_tag
+ hctx_idx
);
1856 blk_mq_sched_exit_hctx(q
, hctx
, hctx_idx
);
1858 if (set
->ops
->exit_hctx
)
1859 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1861 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
1862 cleanup_srcu_struct(&hctx
->queue_rq_srcu
);
1864 blk_mq_remove_cpuhp(hctx
);
1865 blk_free_flush_queue(hctx
->fq
);
1866 sbitmap_free(&hctx
->ctx_map
);
1869 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1870 struct blk_mq_tag_set
*set
, int nr_queue
)
1872 struct blk_mq_hw_ctx
*hctx
;
1875 queue_for_each_hw_ctx(q
, hctx
, i
) {
1878 blk_mq_exit_hctx(q
, set
, hctx
, i
);
1882 static int blk_mq_init_hctx(struct request_queue
*q
,
1883 struct blk_mq_tag_set
*set
,
1884 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
1887 unsigned flush_start_tag
= set
->queue_depth
;
1889 node
= hctx
->numa_node
;
1890 if (node
== NUMA_NO_NODE
)
1891 node
= hctx
->numa_node
= set
->numa_node
;
1893 INIT_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1894 INIT_DELAYED_WORK(&hctx
->delayed_run_work
, blk_mq_delayed_run_work_fn
);
1895 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1896 spin_lock_init(&hctx
->lock
);
1897 INIT_LIST_HEAD(&hctx
->dispatch
);
1899 hctx
->queue_num
= hctx_idx
;
1900 hctx
->flags
= set
->flags
& ~BLK_MQ_F_TAG_SHARED
;
1902 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD
, &hctx
->cpuhp_dead
);
1904 hctx
->tags
= set
->tags
[hctx_idx
];
1907 * Allocate space for all possible cpus to avoid allocation at
1910 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1913 goto unregister_cpu_notifier
;
1915 if (sbitmap_init_node(&hctx
->ctx_map
, nr_cpu_ids
, ilog2(8), GFP_KERNEL
,
1921 if (set
->ops
->init_hctx
&&
1922 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
1925 if (blk_mq_sched_init_hctx(q
, hctx
, hctx_idx
))
1928 hctx
->fq
= blk_alloc_flush_queue(q
, hctx
->numa_node
, set
->cmd_size
);
1930 goto sched_exit_hctx
;
1932 if (set
->ops
->init_request
&&
1933 set
->ops
->init_request(set
->driver_data
,
1934 hctx
->fq
->flush_rq
, hctx_idx
,
1935 flush_start_tag
+ hctx_idx
, node
))
1938 if (hctx
->flags
& BLK_MQ_F_BLOCKING
)
1939 init_srcu_struct(&hctx
->queue_rq_srcu
);
1946 blk_mq_sched_exit_hctx(q
, hctx
, hctx_idx
);
1948 if (set
->ops
->exit_hctx
)
1949 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1951 sbitmap_free(&hctx
->ctx_map
);
1954 unregister_cpu_notifier
:
1955 blk_mq_remove_cpuhp(hctx
);
1959 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1960 unsigned int nr_hw_queues
)
1964 for_each_possible_cpu(i
) {
1965 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1966 struct blk_mq_hw_ctx
*hctx
;
1969 spin_lock_init(&__ctx
->lock
);
1970 INIT_LIST_HEAD(&__ctx
->rq_list
);
1973 /* If the cpu isn't online, the cpu is mapped to first hctx */
1977 hctx
= blk_mq_map_queue(q
, i
);
1980 * Set local node, IFF we have more than one hw queue. If
1981 * not, we remain on the home node of the device
1983 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1984 hctx
->numa_node
= local_memory_node(cpu_to_node(i
));
1988 static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set
*set
, int hctx_idx
)
1992 set
->tags
[hctx_idx
] = blk_mq_alloc_rq_map(set
, hctx_idx
,
1993 set
->queue_depth
, set
->reserved_tags
);
1994 if (!set
->tags
[hctx_idx
])
1997 ret
= blk_mq_alloc_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
,
2002 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2003 set
->tags
[hctx_idx
] = NULL
;
2007 static void blk_mq_free_map_and_requests(struct blk_mq_tag_set
*set
,
2008 unsigned int hctx_idx
)
2010 if (set
->tags
[hctx_idx
]) {
2011 blk_mq_free_rqs(set
, set
->tags
[hctx_idx
], hctx_idx
);
2012 blk_mq_free_rq_map(set
->tags
[hctx_idx
]);
2013 set
->tags
[hctx_idx
] = NULL
;
2017 static void blk_mq_map_swqueue(struct request_queue
*q
,
2018 const struct cpumask
*online_mask
)
2020 unsigned int i
, hctx_idx
;
2021 struct blk_mq_hw_ctx
*hctx
;
2022 struct blk_mq_ctx
*ctx
;
2023 struct blk_mq_tag_set
*set
= q
->tag_set
;
2026 * Avoid others reading imcomplete hctx->cpumask through sysfs
2028 mutex_lock(&q
->sysfs_lock
);
2030 queue_for_each_hw_ctx(q
, hctx
, i
) {
2031 cpumask_clear(hctx
->cpumask
);
2036 * Map software to hardware queues
2038 for_each_possible_cpu(i
) {
2039 /* If the cpu isn't online, the cpu is mapped to first hctx */
2040 if (!cpumask_test_cpu(i
, online_mask
))
2043 hctx_idx
= q
->mq_map
[i
];
2044 /* unmapped hw queue can be remapped after CPU topo changed */
2045 if (!set
->tags
[hctx_idx
] &&
2046 !__blk_mq_alloc_rq_map(set
, hctx_idx
)) {
2048 * If tags initialization fail for some hctx,
2049 * that hctx won't be brought online. In this
2050 * case, remap the current ctx to hctx[0] which
2051 * is guaranteed to always have tags allocated
2056 ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
2057 hctx
= blk_mq_map_queue(q
, i
);
2059 cpumask_set_cpu(i
, hctx
->cpumask
);
2060 ctx
->index_hw
= hctx
->nr_ctx
;
2061 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
2064 mutex_unlock(&q
->sysfs_lock
);
2066 queue_for_each_hw_ctx(q
, hctx
, i
) {
2068 * If no software queues are mapped to this hardware queue,
2069 * disable it and free the request entries.
2071 if (!hctx
->nr_ctx
) {
2072 /* Never unmap queue 0. We need it as a
2073 * fallback in case of a new remap fails
2076 if (i
&& set
->tags
[i
])
2077 blk_mq_free_map_and_requests(set
, i
);
2083 hctx
->tags
= set
->tags
[i
];
2084 WARN_ON(!hctx
->tags
);
2087 * Set the map size to the number of mapped software queues.
2088 * This is more accurate and more efficient than looping
2089 * over all possibly mapped software queues.
2091 sbitmap_resize(&hctx
->ctx_map
, hctx
->nr_ctx
);
2094 * Initialize batch roundrobin counts
2096 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
2097 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
2101 static void queue_set_hctx_shared(struct request_queue
*q
, bool shared
)
2103 struct blk_mq_hw_ctx
*hctx
;
2106 queue_for_each_hw_ctx(q
, hctx
, i
) {
2108 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
2110 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2114 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
, bool shared
)
2116 struct request_queue
*q
;
2118 lockdep_assert_held(&set
->tag_list_lock
);
2120 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
2121 blk_mq_freeze_queue(q
);
2122 queue_set_hctx_shared(q
, shared
);
2123 blk_mq_unfreeze_queue(q
);
2127 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
2129 struct blk_mq_tag_set
*set
= q
->tag_set
;
2131 mutex_lock(&set
->tag_list_lock
);
2132 list_del_rcu(&q
->tag_set_list
);
2133 INIT_LIST_HEAD(&q
->tag_set_list
);
2134 if (list_is_singular(&set
->tag_list
)) {
2135 /* just transitioned to unshared */
2136 set
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
2137 /* update existing queue */
2138 blk_mq_update_tag_set_depth(set
, false);
2140 mutex_unlock(&set
->tag_list_lock
);
2145 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
2146 struct request_queue
*q
)
2150 mutex_lock(&set
->tag_list_lock
);
2152 /* Check to see if we're transitioning to shared (from 1 to 2 queues). */
2153 if (!list_empty(&set
->tag_list
) && !(set
->flags
& BLK_MQ_F_TAG_SHARED
)) {
2154 set
->flags
|= BLK_MQ_F_TAG_SHARED
;
2155 /* update existing queue */
2156 blk_mq_update_tag_set_depth(set
, true);
2158 if (set
->flags
& BLK_MQ_F_TAG_SHARED
)
2159 queue_set_hctx_shared(q
, true);
2160 list_add_tail_rcu(&q
->tag_set_list
, &set
->tag_list
);
2162 mutex_unlock(&set
->tag_list_lock
);
2166 * It is the actual release handler for mq, but we do it from
2167 * request queue's release handler for avoiding use-after-free
2168 * and headache because q->mq_kobj shouldn't have been introduced,
2169 * but we can't group ctx/kctx kobj without it.
2171 void blk_mq_release(struct request_queue
*q
)
2173 struct blk_mq_hw_ctx
*hctx
;
2176 /* hctx kobj stays in hctx */
2177 queue_for_each_hw_ctx(q
, hctx
, i
) {
2180 kobject_put(&hctx
->kobj
);
2185 kfree(q
->queue_hw_ctx
);
2188 * release .mq_kobj and sw queue's kobject now because
2189 * both share lifetime with request queue.
2191 blk_mq_sysfs_deinit(q
);
2193 free_percpu(q
->queue_ctx
);
2196 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
2198 struct request_queue
*uninit_q
, *q
;
2200 uninit_q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
2202 return ERR_PTR(-ENOMEM
);
2204 q
= blk_mq_init_allocated_queue(set
, uninit_q
);
2206 blk_cleanup_queue(uninit_q
);
2210 EXPORT_SYMBOL(blk_mq_init_queue
);
2212 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set
*set
,
2213 struct request_queue
*q
)
2216 struct blk_mq_hw_ctx
**hctxs
= q
->queue_hw_ctx
;
2218 blk_mq_sysfs_unregister(q
);
2219 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2225 node
= blk_mq_hw_queue_to_node(q
->mq_map
, i
);
2226 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
2231 if (!zalloc_cpumask_var_node(&hctxs
[i
]->cpumask
, GFP_KERNEL
,
2238 atomic_set(&hctxs
[i
]->nr_active
, 0);
2239 hctxs
[i
]->numa_node
= node
;
2240 hctxs
[i
]->queue_num
= i
;
2242 if (blk_mq_init_hctx(q
, set
, hctxs
[i
], i
)) {
2243 free_cpumask_var(hctxs
[i
]->cpumask
);
2248 blk_mq_hctx_kobj_init(hctxs
[i
]);
2250 for (j
= i
; j
< q
->nr_hw_queues
; j
++) {
2251 struct blk_mq_hw_ctx
*hctx
= hctxs
[j
];
2255 blk_mq_free_map_and_requests(set
, j
);
2256 blk_mq_exit_hctx(q
, set
, hctx
, j
);
2257 kobject_put(&hctx
->kobj
);
2262 q
->nr_hw_queues
= i
;
2263 blk_mq_sysfs_register(q
);
2266 struct request_queue
*blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
2267 struct request_queue
*q
)
2269 /* mark the queue as mq asap */
2270 q
->mq_ops
= set
->ops
;
2272 q
->poll_cb
= blk_stat_alloc_callback(blk_mq_poll_stats_fn
,
2273 blk_stat_rq_ddir
, 2, q
);
2277 q
->queue_ctx
= alloc_percpu(struct blk_mq_ctx
);
2281 /* init q->mq_kobj and sw queues' kobjects */
2282 blk_mq_sysfs_init(q
);
2284 q
->queue_hw_ctx
= kzalloc_node(nr_cpu_ids
* sizeof(*(q
->queue_hw_ctx
)),
2285 GFP_KERNEL
, set
->numa_node
);
2286 if (!q
->queue_hw_ctx
)
2289 q
->mq_map
= set
->mq_map
;
2291 blk_mq_realloc_hw_ctxs(set
, q
);
2292 if (!q
->nr_hw_queues
)
2295 INIT_WORK(&q
->timeout_work
, blk_mq_timeout_work
);
2296 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
2298 q
->nr_queues
= nr_cpu_ids
;
2300 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
2302 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
2303 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
2305 q
->sg_reserved_size
= INT_MAX
;
2307 INIT_DELAYED_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
2308 INIT_LIST_HEAD(&q
->requeue_list
);
2309 spin_lock_init(&q
->requeue_lock
);
2311 blk_queue_make_request(q
, blk_mq_make_request
);
2314 * Do this after blk_queue_make_request() overrides it...
2316 q
->nr_requests
= set
->queue_depth
;
2319 * Default to classic polling
2323 if (set
->ops
->complete
)
2324 blk_queue_softirq_done(q
, set
->ops
->complete
);
2326 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
2329 mutex_lock(&all_q_mutex
);
2331 list_add_tail(&q
->all_q_node
, &all_q_list
);
2332 blk_mq_add_queue_tag_set(set
, q
);
2333 blk_mq_map_swqueue(q
, cpu_online_mask
);
2335 mutex_unlock(&all_q_mutex
);
2338 if (!(set
->flags
& BLK_MQ_F_NO_SCHED
)) {
2341 ret
= blk_mq_sched_init(q
);
2343 return ERR_PTR(ret
);
2349 kfree(q
->queue_hw_ctx
);
2351 free_percpu(q
->queue_ctx
);
2354 return ERR_PTR(-ENOMEM
);
2356 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
2358 void blk_mq_free_queue(struct request_queue
*q
)
2360 struct blk_mq_tag_set
*set
= q
->tag_set
;
2362 mutex_lock(&all_q_mutex
);
2363 list_del_init(&q
->all_q_node
);
2364 mutex_unlock(&all_q_mutex
);
2366 blk_mq_del_queue_tag_set(q
);
2368 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
2371 /* Basically redo blk_mq_init_queue with queue frozen */
2372 static void blk_mq_queue_reinit(struct request_queue
*q
,
2373 const struct cpumask
*online_mask
)
2375 WARN_ON_ONCE(!atomic_read(&q
->mq_freeze_depth
));
2377 blk_mq_sysfs_unregister(q
);
2380 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
2381 * we should change hctx numa_node according to new topology (this
2382 * involves free and re-allocate memory, worthy doing?)
2385 blk_mq_map_swqueue(q
, online_mask
);
2387 blk_mq_sysfs_register(q
);
2391 * New online cpumask which is going to be set in this hotplug event.
2392 * Declare this cpumasks as global as cpu-hotplug operation is invoked
2393 * one-by-one and dynamically allocating this could result in a failure.
2395 static struct cpumask cpuhp_online_new
;
2397 static void blk_mq_queue_reinit_work(void)
2399 struct request_queue
*q
;
2401 mutex_lock(&all_q_mutex
);
2403 * We need to freeze and reinit all existing queues. Freezing
2404 * involves synchronous wait for an RCU grace period and doing it
2405 * one by one may take a long time. Start freezing all queues in
2406 * one swoop and then wait for the completions so that freezing can
2407 * take place in parallel.
2409 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2410 blk_freeze_queue_start(q
);
2411 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2412 blk_mq_freeze_queue_wait(q
);
2414 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2415 blk_mq_queue_reinit(q
, &cpuhp_online_new
);
2417 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2418 blk_mq_unfreeze_queue(q
);
2420 mutex_unlock(&all_q_mutex
);
2423 static int blk_mq_queue_reinit_dead(unsigned int cpu
)
2425 cpumask_copy(&cpuhp_online_new
, cpu_online_mask
);
2426 blk_mq_queue_reinit_work();
2431 * Before hotadded cpu starts handling requests, new mappings must be
2432 * established. Otherwise, these requests in hw queue might never be
2435 * For example, there is a single hw queue (hctx) and two CPU queues (ctx0
2436 * for CPU0, and ctx1 for CPU1).
2438 * Now CPU1 is just onlined and a request is inserted into ctx1->rq_list
2439 * and set bit0 in pending bitmap as ctx1->index_hw is still zero.
2441 * And then while running hw queue, blk_mq_flush_busy_ctxs() finds bit0 is set
2442 * in pending bitmap and tries to retrieve requests in hctx->ctxs[0]->rq_list.
2443 * But htx->ctxs[0] is a pointer to ctx0, so the request in ctx1->rq_list is
2446 static int blk_mq_queue_reinit_prepare(unsigned int cpu
)
2448 cpumask_copy(&cpuhp_online_new
, cpu_online_mask
);
2449 cpumask_set_cpu(cpu
, &cpuhp_online_new
);
2450 blk_mq_queue_reinit_work();
2454 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2458 for (i
= 0; i
< set
->nr_hw_queues
; i
++)
2459 if (!__blk_mq_alloc_rq_map(set
, i
))
2466 blk_mq_free_rq_map(set
->tags
[i
]);
2472 * Allocate the request maps associated with this tag_set. Note that this
2473 * may reduce the depth asked for, if memory is tight. set->queue_depth
2474 * will be updated to reflect the allocated depth.
2476 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2481 depth
= set
->queue_depth
;
2483 err
= __blk_mq_alloc_rq_maps(set
);
2487 set
->queue_depth
>>= 1;
2488 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
2492 } while (set
->queue_depth
);
2494 if (!set
->queue_depth
|| err
) {
2495 pr_err("blk-mq: failed to allocate request map\n");
2499 if (depth
!= set
->queue_depth
)
2500 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2501 depth
, set
->queue_depth
);
2506 static int blk_mq_update_queue_map(struct blk_mq_tag_set
*set
)
2508 if (set
->ops
->map_queues
)
2509 return set
->ops
->map_queues(set
);
2511 return blk_mq_map_queues(set
);
2515 * Alloc a tag set to be associated with one or more request queues.
2516 * May fail with EINVAL for various error conditions. May adjust the
2517 * requested depth down, if if it too large. In that case, the set
2518 * value will be stored in set->queue_depth.
2520 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2524 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
2526 if (!set
->nr_hw_queues
)
2528 if (!set
->queue_depth
)
2530 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2533 if (!set
->ops
->queue_rq
)
2536 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2537 pr_info("blk-mq: reduced tag depth to %u\n",
2539 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2543 * If a crashdump is active, then we are potentially in a very
2544 * memory constrained environment. Limit us to 1 queue and
2545 * 64 tags to prevent using too much memory.
2547 if (is_kdump_kernel()) {
2548 set
->nr_hw_queues
= 1;
2549 set
->queue_depth
= min(64U, set
->queue_depth
);
2552 * There is no use for more h/w queues than cpus.
2554 if (set
->nr_hw_queues
> nr_cpu_ids
)
2555 set
->nr_hw_queues
= nr_cpu_ids
;
2557 set
->tags
= kzalloc_node(nr_cpu_ids
* sizeof(struct blk_mq_tags
*),
2558 GFP_KERNEL
, set
->numa_node
);
2563 set
->mq_map
= kzalloc_node(sizeof(*set
->mq_map
) * nr_cpu_ids
,
2564 GFP_KERNEL
, set
->numa_node
);
2568 ret
= blk_mq_update_queue_map(set
);
2570 goto out_free_mq_map
;
2572 ret
= blk_mq_alloc_rq_maps(set
);
2574 goto out_free_mq_map
;
2576 mutex_init(&set
->tag_list_lock
);
2577 INIT_LIST_HEAD(&set
->tag_list
);
2589 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2591 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2595 for (i
= 0; i
< nr_cpu_ids
; i
++)
2596 blk_mq_free_map_and_requests(set
, i
);
2604 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2606 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2608 struct blk_mq_tag_set
*set
= q
->tag_set
;
2609 struct blk_mq_hw_ctx
*hctx
;
2615 blk_mq_freeze_queue(q
);
2616 blk_mq_quiesce_queue(q
);
2619 queue_for_each_hw_ctx(q
, hctx
, i
) {
2623 * If we're using an MQ scheduler, just update the scheduler
2624 * queue depth. This is similar to what the old code would do.
2626 if (!hctx
->sched_tags
) {
2627 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->tags
,
2628 min(nr
, set
->queue_depth
),
2631 ret
= blk_mq_tag_update_depth(hctx
, &hctx
->sched_tags
,
2639 q
->nr_requests
= nr
;
2641 blk_mq_unfreeze_queue(q
);
2642 blk_mq_start_stopped_hw_queues(q
, true);
2647 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set
*set
, int nr_hw_queues
)
2649 struct request_queue
*q
;
2651 lockdep_assert_held(&set
->tag_list_lock
);
2653 if (nr_hw_queues
> nr_cpu_ids
)
2654 nr_hw_queues
= nr_cpu_ids
;
2655 if (nr_hw_queues
< 1 || nr_hw_queues
== set
->nr_hw_queues
)
2658 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
2659 blk_mq_freeze_queue(q
);
2661 set
->nr_hw_queues
= nr_hw_queues
;
2662 blk_mq_update_queue_map(set
);
2663 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
2664 blk_mq_realloc_hw_ctxs(set
, q
);
2665 blk_mq_queue_reinit(q
, cpu_online_mask
);
2668 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
)
2669 blk_mq_unfreeze_queue(q
);
2671 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues
);
2673 /* Enable polling stats and return whether they were already enabled. */
2674 static bool blk_poll_stats_enable(struct request_queue
*q
)
2676 if (test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
2677 test_and_set_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
))
2679 blk_stat_add_callback(q
, q
->poll_cb
);
2683 static void blk_mq_poll_stats_start(struct request_queue
*q
)
2686 * We don't arm the callback if polling stats are not enabled or the
2687 * callback is already active.
2689 if (!test_bit(QUEUE_FLAG_POLL_STATS
, &q
->queue_flags
) ||
2690 blk_stat_is_active(q
->poll_cb
))
2693 blk_stat_activate_msecs(q
->poll_cb
, 100);
2696 static void blk_mq_poll_stats_fn(struct blk_stat_callback
*cb
)
2698 struct request_queue
*q
= cb
->data
;
2700 if (cb
->stat
[READ
].nr_samples
)
2701 q
->poll_stat
[READ
] = cb
->stat
[READ
];
2702 if (cb
->stat
[WRITE
].nr_samples
)
2703 q
->poll_stat
[WRITE
] = cb
->stat
[WRITE
];
2706 static unsigned long blk_mq_poll_nsecs(struct request_queue
*q
,
2707 struct blk_mq_hw_ctx
*hctx
,
2710 unsigned long ret
= 0;
2713 * If stats collection isn't on, don't sleep but turn it on for
2716 if (!blk_poll_stats_enable(q
))
2720 * As an optimistic guess, use half of the mean service time
2721 * for this type of request. We can (and should) make this smarter.
2722 * For instance, if the completion latencies are tight, we can
2723 * get closer than just half the mean. This is especially
2724 * important on devices where the completion latencies are longer
2727 if (req_op(rq
) == REQ_OP_READ
&& q
->poll_stat
[READ
].nr_samples
)
2728 ret
= (q
->poll_stat
[READ
].mean
+ 1) / 2;
2729 else if (req_op(rq
) == REQ_OP_WRITE
&& q
->poll_stat
[WRITE
].nr_samples
)
2730 ret
= (q
->poll_stat
[WRITE
].mean
+ 1) / 2;
2735 static bool blk_mq_poll_hybrid_sleep(struct request_queue
*q
,
2736 struct blk_mq_hw_ctx
*hctx
,
2739 struct hrtimer_sleeper hs
;
2740 enum hrtimer_mode mode
;
2744 if (test_bit(REQ_ATOM_POLL_SLEPT
, &rq
->atomic_flags
))
2750 * -1: don't ever hybrid sleep
2751 * 0: use half of prev avg
2752 * >0: use this specific value
2754 if (q
->poll_nsec
== -1)
2756 else if (q
->poll_nsec
> 0)
2757 nsecs
= q
->poll_nsec
;
2759 nsecs
= blk_mq_poll_nsecs(q
, hctx
, rq
);
2764 set_bit(REQ_ATOM_POLL_SLEPT
, &rq
->atomic_flags
);
2767 * This will be replaced with the stats tracking code, using
2768 * 'avg_completion_time / 2' as the pre-sleep target.
2772 mode
= HRTIMER_MODE_REL
;
2773 hrtimer_init_on_stack(&hs
.timer
, CLOCK_MONOTONIC
, mode
);
2774 hrtimer_set_expires(&hs
.timer
, kt
);
2776 hrtimer_init_sleeper(&hs
, current
);
2778 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
2780 set_current_state(TASK_UNINTERRUPTIBLE
);
2781 hrtimer_start_expires(&hs
.timer
, mode
);
2784 hrtimer_cancel(&hs
.timer
);
2785 mode
= HRTIMER_MODE_ABS
;
2786 } while (hs
.task
&& !signal_pending(current
));
2788 __set_current_state(TASK_RUNNING
);
2789 destroy_hrtimer_on_stack(&hs
.timer
);
2793 static bool __blk_mq_poll(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
2795 struct request_queue
*q
= hctx
->queue
;
2799 * If we sleep, have the caller restart the poll loop to reset
2800 * the state. Like for the other success return cases, the
2801 * caller is responsible for checking if the IO completed. If
2802 * the IO isn't complete, we'll get called again and will go
2803 * straight to the busy poll loop.
2805 if (blk_mq_poll_hybrid_sleep(q
, hctx
, rq
))
2808 hctx
->poll_considered
++;
2810 state
= current
->state
;
2811 while (!need_resched()) {
2814 hctx
->poll_invoked
++;
2816 ret
= q
->mq_ops
->poll(hctx
, rq
->tag
);
2818 hctx
->poll_success
++;
2819 set_current_state(TASK_RUNNING
);
2823 if (signal_pending_state(state
, current
))
2824 set_current_state(TASK_RUNNING
);
2826 if (current
->state
== TASK_RUNNING
)
2836 bool blk_mq_poll(struct request_queue
*q
, blk_qc_t cookie
)
2838 struct blk_mq_hw_ctx
*hctx
;
2839 struct blk_plug
*plug
;
2842 if (!q
->mq_ops
|| !q
->mq_ops
->poll
|| !blk_qc_t_valid(cookie
) ||
2843 !test_bit(QUEUE_FLAG_POLL
, &q
->queue_flags
))
2846 plug
= current
->plug
;
2848 blk_flush_plug_list(plug
, false);
2850 hctx
= q
->queue_hw_ctx
[blk_qc_t_to_queue_num(cookie
)];
2851 if (!blk_qc_t_is_internal(cookie
))
2852 rq
= blk_mq_tag_to_rq(hctx
->tags
, blk_qc_t_to_tag(cookie
));
2854 rq
= blk_mq_tag_to_rq(hctx
->sched_tags
, blk_qc_t_to_tag(cookie
));
2856 return __blk_mq_poll(hctx
, rq
);
2858 EXPORT_SYMBOL_GPL(blk_mq_poll
);
2860 void blk_mq_disable_hotplug(void)
2862 mutex_lock(&all_q_mutex
);
2865 void blk_mq_enable_hotplug(void)
2867 mutex_unlock(&all_q_mutex
);
2870 static int __init
blk_mq_init(void)
2872 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD
, "block/mq:dead", NULL
,
2873 blk_mq_hctx_notify_dead
);
2875 cpuhp_setup_state_nocalls(CPUHP_BLK_MQ_PREPARE
, "block/mq:prepare",
2876 blk_mq_queue_reinit_prepare
,
2877 blk_mq_queue_reinit_dead
);
2880 subsys_initcall(blk_mq_init
);