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>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/workqueue.h>
16 #include <linux/smp.h>
17 #include <linux/llist.h>
18 #include <linux/list_sort.h>
19 #include <linux/cpu.h>
20 #include <linux/cache.h>
21 #include <linux/sched/sysctl.h>
22 #include <linux/delay.h>
23 #include <linux/crash_dump.h>
25 #include <trace/events/block.h>
27 #include <linux/blk-mq.h>
30 #include "blk-mq-tag.h"
32 static DEFINE_MUTEX(all_q_mutex
);
33 static LIST_HEAD(all_q_list
);
35 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
38 * Check if any of the ctx's have pending work in this hardware queue
40 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
44 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++)
45 if (hctx
->ctx_map
.map
[i
].word
)
51 static inline struct blk_align_bitmap
*get_bm(struct blk_mq_hw_ctx
*hctx
,
52 struct blk_mq_ctx
*ctx
)
54 return &hctx
->ctx_map
.map
[ctx
->index_hw
/ hctx
->ctx_map
.bits_per_word
];
57 #define CTX_TO_BIT(hctx, ctx) \
58 ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
61 * Mark this ctx as having pending work in this hardware queue
63 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
64 struct blk_mq_ctx
*ctx
)
66 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
68 if (!test_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
))
69 set_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
72 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
73 struct blk_mq_ctx
*ctx
)
75 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
77 clear_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
80 static int blk_mq_queue_enter(struct request_queue
*q
)
85 if (percpu_ref_tryget_live(&q
->mq_usage_counter
))
88 ret
= wait_event_interruptible(q
->mq_freeze_wq
,
89 !q
->mq_freeze_depth
|| blk_queue_dying(q
));
90 if (blk_queue_dying(q
))
97 static void blk_mq_queue_exit(struct request_queue
*q
)
99 percpu_ref_put(&q
->mq_usage_counter
);
102 static void blk_mq_usage_counter_release(struct percpu_ref
*ref
)
104 struct request_queue
*q
=
105 container_of(ref
, struct request_queue
, mq_usage_counter
);
107 wake_up_all(&q
->mq_freeze_wq
);
111 * Guarantee no request is in use, so we can change any data structure of
112 * the queue afterward.
114 void blk_mq_freeze_queue(struct request_queue
*q
)
118 spin_lock_irq(q
->queue_lock
);
119 freeze
= !q
->mq_freeze_depth
++;
120 spin_unlock_irq(q
->queue_lock
);
123 percpu_ref_kill(&q
->mq_usage_counter
);
124 blk_mq_run_queues(q
, false);
126 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->mq_usage_counter
));
129 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
133 spin_lock_irq(q
->queue_lock
);
134 wake
= !--q
->mq_freeze_depth
;
135 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
136 spin_unlock_irq(q
->queue_lock
);
138 percpu_ref_reinit(&q
->mq_usage_counter
);
139 wake_up_all(&q
->mq_freeze_wq
);
143 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
145 return blk_mq_has_free_tags(hctx
->tags
);
147 EXPORT_SYMBOL(blk_mq_can_queue
);
149 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
150 struct request
*rq
, unsigned int rw_flags
)
152 if (blk_queue_io_stat(q
))
153 rw_flags
|= REQ_IO_STAT
;
155 INIT_LIST_HEAD(&rq
->queuelist
);
156 /* csd/requeue_work/fifo_time is initialized before use */
159 rq
->cmd_flags
|= rw_flags
;
160 /* do not touch atomic flags, it needs atomic ops against the timer */
162 INIT_HLIST_NODE(&rq
->hash
);
163 RB_CLEAR_NODE(&rq
->rb_node
);
166 rq
->start_time
= jiffies
;
167 #ifdef CONFIG_BLK_CGROUP
169 set_start_time_ns(rq
);
170 rq
->io_start_time_ns
= 0;
172 rq
->nr_phys_segments
= 0;
173 #if defined(CONFIG_BLK_DEV_INTEGRITY)
174 rq
->nr_integrity_segments
= 0;
177 /* tag was already set */
187 INIT_LIST_HEAD(&rq
->timeout_list
);
191 rq
->end_io_data
= NULL
;
194 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
197 static struct request
*
198 __blk_mq_alloc_request(struct blk_mq_alloc_data
*data
, int rw
)
203 tag
= blk_mq_get_tag(data
);
204 if (tag
!= BLK_MQ_TAG_FAIL
) {
205 rq
= data
->hctx
->tags
->rqs
[tag
];
207 if (blk_mq_tag_busy(data
->hctx
)) {
208 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
209 atomic_inc(&data
->hctx
->nr_active
);
213 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, rw
);
220 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
223 struct blk_mq_ctx
*ctx
;
224 struct blk_mq_hw_ctx
*hctx
;
226 struct blk_mq_alloc_data alloc_data
;
229 ret
= blk_mq_queue_enter(q
);
233 ctx
= blk_mq_get_ctx(q
);
234 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
235 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
& ~__GFP_WAIT
,
236 reserved
, ctx
, hctx
);
238 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
239 if (!rq
&& (gfp
& __GFP_WAIT
)) {
240 __blk_mq_run_hw_queue(hctx
);
243 ctx
= blk_mq_get_ctx(q
);
244 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
245 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
, reserved
, ctx
,
247 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
248 ctx
= alloc_data
.ctx
;
252 return ERR_PTR(-EWOULDBLOCK
);
255 EXPORT_SYMBOL(blk_mq_alloc_request
);
257 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
258 struct blk_mq_ctx
*ctx
, struct request
*rq
)
260 const int tag
= rq
->tag
;
261 struct request_queue
*q
= rq
->q
;
263 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
264 atomic_dec(&hctx
->nr_active
);
267 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
268 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
269 blk_mq_queue_exit(q
);
272 void blk_mq_free_hctx_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
274 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
276 ctx
->rq_completed
[rq_is_sync(rq
)]++;
277 __blk_mq_free_request(hctx
, ctx
, rq
);
280 EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request
);
282 void blk_mq_free_request(struct request
*rq
)
284 struct blk_mq_hw_ctx
*hctx
;
285 struct request_queue
*q
= rq
->q
;
287 hctx
= q
->mq_ops
->map_queue(q
, rq
->mq_ctx
->cpu
);
288 blk_mq_free_hctx_request(hctx
, rq
);
290 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
292 inline void __blk_mq_end_request(struct request
*rq
, int error
)
294 blk_account_io_done(rq
);
297 rq
->end_io(rq
, error
);
299 if (unlikely(blk_bidi_rq(rq
)))
300 blk_mq_free_request(rq
->next_rq
);
301 blk_mq_free_request(rq
);
304 EXPORT_SYMBOL(__blk_mq_end_request
);
306 void blk_mq_end_request(struct request
*rq
, int error
)
308 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
310 __blk_mq_end_request(rq
, error
);
312 EXPORT_SYMBOL(blk_mq_end_request
);
314 static void __blk_mq_complete_request_remote(void *data
)
316 struct request
*rq
= data
;
318 rq
->q
->softirq_done_fn(rq
);
321 static void blk_mq_ipi_complete_request(struct request
*rq
)
323 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
327 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
328 rq
->q
->softirq_done_fn(rq
);
333 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
334 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
336 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
337 rq
->csd
.func
= __blk_mq_complete_request_remote
;
340 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
342 rq
->q
->softirq_done_fn(rq
);
347 void __blk_mq_complete_request(struct request
*rq
)
349 struct request_queue
*q
= rq
->q
;
351 if (!q
->softirq_done_fn
)
352 blk_mq_end_request(rq
, rq
->errors
);
354 blk_mq_ipi_complete_request(rq
);
358 * blk_mq_complete_request - end I/O on a request
359 * @rq: the request being processed
362 * Ends all I/O on a request. It does not handle partial completions.
363 * The actual completion happens out-of-order, through a IPI handler.
365 void blk_mq_complete_request(struct request
*rq
)
367 struct request_queue
*q
= rq
->q
;
369 if (unlikely(blk_should_fake_timeout(q
)))
371 if (!blk_mark_rq_complete(rq
))
372 __blk_mq_complete_request(rq
);
374 EXPORT_SYMBOL(blk_mq_complete_request
);
376 void blk_mq_start_request(struct request
*rq
)
378 struct request_queue
*q
= rq
->q
;
380 trace_block_rq_issue(q
, rq
);
382 rq
->resid_len
= blk_rq_bytes(rq
);
383 if (unlikely(blk_bidi_rq(rq
)))
384 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
389 * Ensure that ->deadline is visible before set the started
390 * flag and clear the completed flag.
392 smp_mb__before_atomic();
395 * Mark us as started and clear complete. Complete might have been
396 * set if requeue raced with timeout, which then marked it as
397 * complete. So be sure to clear complete again when we start
398 * the request, otherwise we'll ignore the completion event.
400 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
401 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
402 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
403 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
405 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
407 * Make sure space for the drain appears. We know we can do
408 * this because max_hw_segments has been adjusted to be one
409 * fewer than the device can handle.
411 rq
->nr_phys_segments
++;
414 EXPORT_SYMBOL(blk_mq_start_request
);
416 static void __blk_mq_requeue_request(struct request
*rq
)
418 struct request_queue
*q
= rq
->q
;
420 trace_block_rq_requeue(q
, rq
);
422 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
423 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
424 rq
->nr_phys_segments
--;
428 void blk_mq_requeue_request(struct request
*rq
)
430 __blk_mq_requeue_request(rq
);
432 BUG_ON(blk_queued_rq(rq
));
433 blk_mq_add_to_requeue_list(rq
, true);
435 EXPORT_SYMBOL(blk_mq_requeue_request
);
437 static void blk_mq_requeue_work(struct work_struct
*work
)
439 struct request_queue
*q
=
440 container_of(work
, struct request_queue
, requeue_work
);
442 struct request
*rq
, *next
;
445 spin_lock_irqsave(&q
->requeue_lock
, flags
);
446 list_splice_init(&q
->requeue_list
, &rq_list
);
447 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
449 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
450 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
453 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
454 list_del_init(&rq
->queuelist
);
455 blk_mq_insert_request(rq
, true, false, false);
458 while (!list_empty(&rq_list
)) {
459 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
460 list_del_init(&rq
->queuelist
);
461 blk_mq_insert_request(rq
, false, false, false);
465 * Use the start variant of queue running here, so that running
466 * the requeue work will kick stopped queues.
468 blk_mq_start_hw_queues(q
);
471 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
473 struct request_queue
*q
= rq
->q
;
477 * We abuse this flag that is otherwise used by the I/O scheduler to
478 * request head insertation from the workqueue.
480 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
482 spin_lock_irqsave(&q
->requeue_lock
, flags
);
484 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
485 list_add(&rq
->queuelist
, &q
->requeue_list
);
487 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
489 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
491 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
493 void blk_mq_kick_requeue_list(struct request_queue
*q
)
495 kblockd_schedule_work(&q
->requeue_work
);
497 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
499 static inline bool is_flush_request(struct request
*rq
,
500 struct blk_flush_queue
*fq
, unsigned int tag
)
502 return ((rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
503 fq
->flush_rq
->tag
== tag
);
506 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
508 struct request
*rq
= tags
->rqs
[tag
];
509 /* mq_ctx of flush rq is always cloned from the corresponding req */
510 struct blk_flush_queue
*fq
= blk_get_flush_queue(rq
->q
, rq
->mq_ctx
);
512 if (!is_flush_request(rq
, fq
, tag
))
517 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
519 struct blk_mq_timeout_data
{
521 unsigned int next_set
;
524 void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
526 struct blk_mq_ops
*ops
= req
->q
->mq_ops
;
527 enum blk_eh_timer_return ret
= BLK_EH_RESET_TIMER
;
530 * We know that complete is set at this point. If STARTED isn't set
531 * anymore, then the request isn't active and the "timeout" should
532 * just be ignored. This can happen due to the bitflag ordering.
533 * Timeout first checks if STARTED is set, and if it is, assumes
534 * the request is active. But if we race with completion, then
535 * we both flags will get cleared. So check here again, and ignore
536 * a timeout event with a request that isn't active.
538 if (!test_bit(REQ_ATOM_STARTED
, &req
->atomic_flags
))
542 ret
= ops
->timeout(req
, reserved
);
546 __blk_mq_complete_request(req
);
548 case BLK_EH_RESET_TIMER
:
550 blk_clear_rq_complete(req
);
552 case BLK_EH_NOT_HANDLED
:
555 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
560 static void blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
561 struct request
*rq
, void *priv
, bool reserved
)
563 struct blk_mq_timeout_data
*data
= priv
;
565 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
568 if (time_after_eq(jiffies
, rq
->deadline
)) {
569 if (!blk_mark_rq_complete(rq
))
570 blk_mq_rq_timed_out(rq
, reserved
);
571 } else if (!data
->next_set
|| time_after(data
->next
, rq
->deadline
)) {
572 data
->next
= rq
->deadline
;
577 static void blk_mq_rq_timer(unsigned long priv
)
579 struct request_queue
*q
= (struct request_queue
*)priv
;
580 struct blk_mq_timeout_data data
= {
584 struct blk_mq_hw_ctx
*hctx
;
587 queue_for_each_hw_ctx(q
, hctx
, i
) {
589 * If not software queues are currently mapped to this
590 * hardware queue, there's nothing to check
592 if (!hctx
->nr_ctx
|| !hctx
->tags
)
595 blk_mq_tag_busy_iter(hctx
, blk_mq_check_expired
, &data
);
599 data
.next
= blk_rq_timeout(round_jiffies_up(data
.next
));
600 mod_timer(&q
->timeout
, data
.next
);
602 queue_for_each_hw_ctx(q
, hctx
, i
)
603 blk_mq_tag_idle(hctx
);
608 * Reverse check our software queue for entries that we could potentially
609 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
610 * too much time checking for merges.
612 static bool blk_mq_attempt_merge(struct request_queue
*q
,
613 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
618 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
624 if (!blk_rq_merge_ok(rq
, bio
))
627 el_ret
= blk_try_merge(rq
, bio
);
628 if (el_ret
== ELEVATOR_BACK_MERGE
) {
629 if (bio_attempt_back_merge(q
, rq
, bio
)) {
634 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
635 if (bio_attempt_front_merge(q
, rq
, bio
)) {
647 * Process software queues that have been marked busy, splicing them
648 * to the for-dispatch
650 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
652 struct blk_mq_ctx
*ctx
;
655 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
656 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
657 unsigned int off
, bit
;
663 off
= i
* hctx
->ctx_map
.bits_per_word
;
665 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
666 if (bit
>= bm
->depth
)
669 ctx
= hctx
->ctxs
[bit
+ off
];
670 clear_bit(bit
, &bm
->word
);
671 spin_lock(&ctx
->lock
);
672 list_splice_tail_init(&ctx
->rq_list
, list
);
673 spin_unlock(&ctx
->lock
);
681 * Run this hardware queue, pulling any software queues mapped to it in.
682 * Note that this function currently has various problems around ordering
683 * of IO. In particular, we'd like FIFO behaviour on handling existing
684 * items on the hctx->dispatch list. Ignore that for now.
686 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
688 struct request_queue
*q
= hctx
->queue
;
691 LIST_HEAD(driver_list
);
692 struct list_head
*dptr
;
695 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
697 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
703 * Touch any software queue that has pending entries.
705 flush_busy_ctxs(hctx
, &rq_list
);
708 * If we have previous entries on our dispatch list, grab them
709 * and stuff them at the front for more fair dispatch.
711 if (!list_empty_careful(&hctx
->dispatch
)) {
712 spin_lock(&hctx
->lock
);
713 if (!list_empty(&hctx
->dispatch
))
714 list_splice_init(&hctx
->dispatch
, &rq_list
);
715 spin_unlock(&hctx
->lock
);
719 * Start off with dptr being NULL, so we start the first request
720 * immediately, even if we have more pending.
725 * Now process all the entries, sending them to the driver.
728 while (!list_empty(&rq_list
)) {
729 struct blk_mq_queue_data bd
;
732 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
733 list_del_init(&rq
->queuelist
);
737 bd
.last
= list_empty(&rq_list
);
739 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
741 case BLK_MQ_RQ_QUEUE_OK
:
744 case BLK_MQ_RQ_QUEUE_BUSY
:
745 list_add(&rq
->queuelist
, &rq_list
);
746 __blk_mq_requeue_request(rq
);
749 pr_err("blk-mq: bad return on queue: %d\n", ret
);
750 case BLK_MQ_RQ_QUEUE_ERROR
:
752 blk_mq_end_request(rq
, rq
->errors
);
756 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
760 * We've done the first request. If we have more than 1
761 * left in the list, set dptr to defer issue.
763 if (!dptr
&& rq_list
.next
!= rq_list
.prev
)
768 hctx
->dispatched
[0]++;
769 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
770 hctx
->dispatched
[ilog2(queued
) + 1]++;
773 * Any items that need requeuing? Stuff them into hctx->dispatch,
774 * that is where we will continue on next queue run.
776 if (!list_empty(&rq_list
)) {
777 spin_lock(&hctx
->lock
);
778 list_splice(&rq_list
, &hctx
->dispatch
);
779 spin_unlock(&hctx
->lock
);
784 * It'd be great if the workqueue API had a way to pass
785 * in a mask and had some smarts for more clever placement.
786 * For now we just round-robin here, switching for every
787 * BLK_MQ_CPU_WORK_BATCH queued items.
789 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
791 int cpu
= hctx
->next_cpu
;
793 if (--hctx
->next_cpu_batch
<= 0) {
796 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
797 if (next_cpu
>= nr_cpu_ids
)
798 next_cpu
= cpumask_first(hctx
->cpumask
);
800 hctx
->next_cpu
= next_cpu
;
801 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
807 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
809 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
814 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
815 __blk_mq_run_hw_queue(hctx
);
823 if (hctx
->queue
->nr_hw_queues
== 1)
824 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
828 cpu
= blk_mq_hctx_next_cpu(hctx
);
829 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
833 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
835 struct blk_mq_hw_ctx
*hctx
;
838 queue_for_each_hw_ctx(q
, hctx
, i
) {
839 if ((!blk_mq_hctx_has_pending(hctx
) &&
840 list_empty_careful(&hctx
->dispatch
)) ||
841 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
844 blk_mq_run_hw_queue(hctx
, async
);
847 EXPORT_SYMBOL(blk_mq_run_queues
);
849 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
851 cancel_delayed_work(&hctx
->run_work
);
852 cancel_delayed_work(&hctx
->delay_work
);
853 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
855 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
857 void blk_mq_stop_hw_queues(struct request_queue
*q
)
859 struct blk_mq_hw_ctx
*hctx
;
862 queue_for_each_hw_ctx(q
, hctx
, i
)
863 blk_mq_stop_hw_queue(hctx
);
865 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
867 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
869 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
871 blk_mq_run_hw_queue(hctx
, false);
873 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
875 void blk_mq_start_hw_queues(struct request_queue
*q
)
877 struct blk_mq_hw_ctx
*hctx
;
880 queue_for_each_hw_ctx(q
, hctx
, i
)
881 blk_mq_start_hw_queue(hctx
);
883 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
886 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
888 struct blk_mq_hw_ctx
*hctx
;
891 queue_for_each_hw_ctx(q
, hctx
, i
) {
892 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
895 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
896 blk_mq_run_hw_queue(hctx
, async
);
899 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
901 static void blk_mq_run_work_fn(struct work_struct
*work
)
903 struct blk_mq_hw_ctx
*hctx
;
905 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
907 __blk_mq_run_hw_queue(hctx
);
910 static void blk_mq_delay_work_fn(struct work_struct
*work
)
912 struct blk_mq_hw_ctx
*hctx
;
914 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
916 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
917 __blk_mq_run_hw_queue(hctx
);
920 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
922 unsigned long tmo
= msecs_to_jiffies(msecs
);
924 if (hctx
->queue
->nr_hw_queues
== 1)
925 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
929 cpu
= blk_mq_hctx_next_cpu(hctx
);
930 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
933 EXPORT_SYMBOL(blk_mq_delay_queue
);
935 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
936 struct request
*rq
, bool at_head
)
938 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
940 trace_block_rq_insert(hctx
->queue
, rq
);
943 list_add(&rq
->queuelist
, &ctx
->rq_list
);
945 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
947 blk_mq_hctx_mark_pending(hctx
, ctx
);
950 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
953 struct request_queue
*q
= rq
->q
;
954 struct blk_mq_hw_ctx
*hctx
;
955 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
957 current_ctx
= blk_mq_get_ctx(q
);
958 if (!cpu_online(ctx
->cpu
))
959 rq
->mq_ctx
= ctx
= current_ctx
;
961 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
963 spin_lock(&ctx
->lock
);
964 __blk_mq_insert_request(hctx
, rq
, at_head
);
965 spin_unlock(&ctx
->lock
);
968 blk_mq_run_hw_queue(hctx
, async
);
970 blk_mq_put_ctx(current_ctx
);
973 static void blk_mq_insert_requests(struct request_queue
*q
,
974 struct blk_mq_ctx
*ctx
,
975 struct list_head
*list
,
980 struct blk_mq_hw_ctx
*hctx
;
981 struct blk_mq_ctx
*current_ctx
;
983 trace_block_unplug(q
, depth
, !from_schedule
);
985 current_ctx
= blk_mq_get_ctx(q
);
987 if (!cpu_online(ctx
->cpu
))
989 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
992 * preemption doesn't flush plug list, so it's possible ctx->cpu is
995 spin_lock(&ctx
->lock
);
996 while (!list_empty(list
)) {
999 rq
= list_first_entry(list
, struct request
, queuelist
);
1000 list_del_init(&rq
->queuelist
);
1002 __blk_mq_insert_request(hctx
, rq
, false);
1004 spin_unlock(&ctx
->lock
);
1006 blk_mq_run_hw_queue(hctx
, from_schedule
);
1007 blk_mq_put_ctx(current_ctx
);
1010 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1012 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1013 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1015 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1016 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1017 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1020 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1022 struct blk_mq_ctx
*this_ctx
;
1023 struct request_queue
*this_q
;
1026 LIST_HEAD(ctx_list
);
1029 list_splice_init(&plug
->mq_list
, &list
);
1031 list_sort(NULL
, &list
, plug_ctx_cmp
);
1037 while (!list_empty(&list
)) {
1038 rq
= list_entry_rq(list
.next
);
1039 list_del_init(&rq
->queuelist
);
1041 if (rq
->mq_ctx
!= this_ctx
) {
1043 blk_mq_insert_requests(this_q
, this_ctx
,
1048 this_ctx
= rq
->mq_ctx
;
1054 list_add_tail(&rq
->queuelist
, &ctx_list
);
1058 * If 'this_ctx' is set, we know we have entries to complete
1059 * on 'ctx_list'. Do those.
1062 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1067 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1069 init_request_from_bio(rq
, bio
);
1071 if (blk_do_io_stat(rq
))
1072 blk_account_io_start(rq
, 1);
1075 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1077 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1078 !blk_queue_nomerges(hctx
->queue
);
1081 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1082 struct blk_mq_ctx
*ctx
,
1083 struct request
*rq
, struct bio
*bio
)
1085 if (!hctx_allow_merges(hctx
)) {
1086 blk_mq_bio_to_request(rq
, bio
);
1087 spin_lock(&ctx
->lock
);
1089 __blk_mq_insert_request(hctx
, rq
, false);
1090 spin_unlock(&ctx
->lock
);
1093 struct request_queue
*q
= hctx
->queue
;
1095 spin_lock(&ctx
->lock
);
1096 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1097 blk_mq_bio_to_request(rq
, bio
);
1101 spin_unlock(&ctx
->lock
);
1102 __blk_mq_free_request(hctx
, ctx
, rq
);
1107 struct blk_map_ctx
{
1108 struct blk_mq_hw_ctx
*hctx
;
1109 struct blk_mq_ctx
*ctx
;
1112 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1114 struct blk_map_ctx
*data
)
1116 struct blk_mq_hw_ctx
*hctx
;
1117 struct blk_mq_ctx
*ctx
;
1119 int rw
= bio_data_dir(bio
);
1120 struct blk_mq_alloc_data alloc_data
;
1122 if (unlikely(blk_mq_queue_enter(q
))) {
1123 bio_endio(bio
, -EIO
);
1127 ctx
= blk_mq_get_ctx(q
);
1128 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1130 if (rw_is_sync(bio
->bi_rw
))
1133 trace_block_getrq(q
, bio
, rw
);
1134 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1136 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1137 if (unlikely(!rq
)) {
1138 __blk_mq_run_hw_queue(hctx
);
1139 blk_mq_put_ctx(ctx
);
1140 trace_block_sleeprq(q
, bio
, rw
);
1142 ctx
= blk_mq_get_ctx(q
);
1143 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1144 blk_mq_set_alloc_data(&alloc_data
, q
,
1145 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1146 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1147 ctx
= alloc_data
.ctx
;
1148 hctx
= alloc_data
.hctx
;
1158 * Multiple hardware queue variant. This will not use per-process plugs,
1159 * but will attempt to bypass the hctx queueing if we can go straight to
1160 * hardware for SYNC IO.
1162 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1164 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1165 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1166 struct blk_map_ctx data
;
1169 blk_queue_bounce(q
, &bio
);
1171 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1172 bio_endio(bio
, -EIO
);
1176 rq
= blk_mq_map_request(q
, bio
, &data
);
1180 if (unlikely(is_flush_fua
)) {
1181 blk_mq_bio_to_request(rq
, bio
);
1182 blk_insert_flush(rq
);
1187 * If the driver supports defer issued based on 'last', then
1188 * queue it up like normal since we can potentially save some
1191 if (is_sync
&& !(data
.hctx
->flags
& BLK_MQ_F_DEFER_ISSUE
)) {
1192 struct blk_mq_queue_data bd
= {
1199 blk_mq_bio_to_request(rq
, bio
);
1202 * For OK queue, we are done. For error, kill it. Any other
1203 * error (busy), just add it to our list as we previously
1206 ret
= q
->mq_ops
->queue_rq(data
.hctx
, &bd
);
1207 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1210 __blk_mq_requeue_request(rq
);
1212 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1214 blk_mq_end_request(rq
, rq
->errors
);
1220 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1222 * For a SYNC request, send it to the hardware immediately. For
1223 * an ASYNC request, just ensure that we run it later on. The
1224 * latter allows for merging opportunities and more efficient
1228 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1231 blk_mq_put_ctx(data
.ctx
);
1235 * Single hardware queue variant. This will attempt to use any per-process
1236 * plug for merging and IO deferral.
1238 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1240 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1241 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1242 unsigned int use_plug
, request_count
= 0;
1243 struct blk_map_ctx data
;
1247 * If we have multiple hardware queues, just go directly to
1248 * one of those for sync IO.
1250 use_plug
= !is_flush_fua
&& !is_sync
;
1252 blk_queue_bounce(q
, &bio
);
1254 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1255 bio_endio(bio
, -EIO
);
1259 if (use_plug
&& !blk_queue_nomerges(q
) &&
1260 blk_attempt_plug_merge(q
, bio
, &request_count
))
1263 rq
= blk_mq_map_request(q
, bio
, &data
);
1267 if (unlikely(is_flush_fua
)) {
1268 blk_mq_bio_to_request(rq
, bio
);
1269 blk_insert_flush(rq
);
1274 * A task plug currently exists. Since this is completely lockless,
1275 * utilize that to temporarily store requests until the task is
1276 * either done or scheduled away.
1279 struct blk_plug
*plug
= current
->plug
;
1282 blk_mq_bio_to_request(rq
, bio
);
1283 if (list_empty(&plug
->mq_list
))
1284 trace_block_plug(q
);
1285 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1286 blk_flush_plug_list(plug
, false);
1287 trace_block_plug(q
);
1289 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1290 blk_mq_put_ctx(data
.ctx
);
1295 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1297 * For a SYNC request, send it to the hardware immediately. For
1298 * an ASYNC request, just ensure that we run it later on. The
1299 * latter allows for merging opportunities and more efficient
1303 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1306 blk_mq_put_ctx(data
.ctx
);
1310 * Default mapping to a software queue, since we use one per CPU.
1312 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1314 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1316 EXPORT_SYMBOL(blk_mq_map_queue
);
1318 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1319 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1323 if (tags
->rqs
&& set
->ops
->exit_request
) {
1326 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1329 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1331 tags
->rqs
[i
] = NULL
;
1335 while (!list_empty(&tags
->page_list
)) {
1336 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1337 list_del_init(&page
->lru
);
1338 __free_pages(page
, page
->private);
1343 blk_mq_free_tags(tags
);
1346 static size_t order_to_size(unsigned int order
)
1348 return (size_t)PAGE_SIZE
<< order
;
1351 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1352 unsigned int hctx_idx
)
1354 struct blk_mq_tags
*tags
;
1355 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1356 size_t rq_size
, left
;
1358 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1363 INIT_LIST_HEAD(&tags
->page_list
);
1365 tags
->rqs
= kzalloc_node(set
->queue_depth
* sizeof(struct request
*),
1366 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1369 blk_mq_free_tags(tags
);
1374 * rq_size is the size of the request plus driver payload, rounded
1375 * to the cacheline size
1377 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1379 left
= rq_size
* set
->queue_depth
;
1381 for (i
= 0; i
< set
->queue_depth
; ) {
1382 int this_order
= max_order
;
1387 while (left
< order_to_size(this_order
- 1) && this_order
)
1391 page
= alloc_pages_node(set
->numa_node
,
1392 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1398 if (order_to_size(this_order
) < rq_size
)
1405 page
->private = this_order
;
1406 list_add_tail(&page
->lru
, &tags
->page_list
);
1408 p
= page_address(page
);
1409 entries_per_page
= order_to_size(this_order
) / rq_size
;
1410 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1411 left
-= to_do
* rq_size
;
1412 for (j
= 0; j
< to_do
; j
++) {
1414 tags
->rqs
[i
]->atomic_flags
= 0;
1415 tags
->rqs
[i
]->cmd_flags
= 0;
1416 if (set
->ops
->init_request
) {
1417 if (set
->ops
->init_request(set
->driver_data
,
1418 tags
->rqs
[i
], hctx_idx
, i
,
1420 tags
->rqs
[i
] = NULL
;
1433 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1437 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1442 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1444 unsigned int bpw
= 8, total
, num_maps
, i
;
1446 bitmap
->bits_per_word
= bpw
;
1448 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1449 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1454 bitmap
->map_size
= num_maps
;
1457 for (i
= 0; i
< num_maps
; i
++) {
1458 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1459 total
-= bitmap
->map
[i
].depth
;
1465 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1467 struct request_queue
*q
= hctx
->queue
;
1468 struct blk_mq_ctx
*ctx
;
1472 * Move ctx entries to new CPU, if this one is going away.
1474 ctx
= __blk_mq_get_ctx(q
, cpu
);
1476 spin_lock(&ctx
->lock
);
1477 if (!list_empty(&ctx
->rq_list
)) {
1478 list_splice_init(&ctx
->rq_list
, &tmp
);
1479 blk_mq_hctx_clear_pending(hctx
, ctx
);
1481 spin_unlock(&ctx
->lock
);
1483 if (list_empty(&tmp
))
1486 ctx
= blk_mq_get_ctx(q
);
1487 spin_lock(&ctx
->lock
);
1489 while (!list_empty(&tmp
)) {
1492 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1494 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1497 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1498 blk_mq_hctx_mark_pending(hctx
, ctx
);
1500 spin_unlock(&ctx
->lock
);
1502 blk_mq_run_hw_queue(hctx
, true);
1503 blk_mq_put_ctx(ctx
);
1507 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1509 struct request_queue
*q
= hctx
->queue
;
1510 struct blk_mq_tag_set
*set
= q
->tag_set
;
1512 if (set
->tags
[hctx
->queue_num
])
1515 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1516 if (!set
->tags
[hctx
->queue_num
])
1519 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1523 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1526 struct blk_mq_hw_ctx
*hctx
= data
;
1528 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1529 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1530 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1531 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1536 static void blk_mq_exit_hctx(struct request_queue
*q
,
1537 struct blk_mq_tag_set
*set
,
1538 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1540 unsigned flush_start_tag
= set
->queue_depth
;
1542 blk_mq_tag_idle(hctx
);
1544 if (set
->ops
->exit_request
)
1545 set
->ops
->exit_request(set
->driver_data
,
1546 hctx
->fq
->flush_rq
, hctx_idx
,
1547 flush_start_tag
+ hctx_idx
);
1549 if (set
->ops
->exit_hctx
)
1550 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1552 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1553 blk_free_flush_queue(hctx
->fq
);
1555 blk_mq_free_bitmap(&hctx
->ctx_map
);
1558 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1559 struct blk_mq_tag_set
*set
, int nr_queue
)
1561 struct blk_mq_hw_ctx
*hctx
;
1564 queue_for_each_hw_ctx(q
, hctx
, i
) {
1567 blk_mq_exit_hctx(q
, set
, hctx
, i
);
1571 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1572 struct blk_mq_tag_set
*set
)
1574 struct blk_mq_hw_ctx
*hctx
;
1577 queue_for_each_hw_ctx(q
, hctx
, i
) {
1578 free_cpumask_var(hctx
->cpumask
);
1583 static int blk_mq_init_hctx(struct request_queue
*q
,
1584 struct blk_mq_tag_set
*set
,
1585 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
1588 unsigned flush_start_tag
= set
->queue_depth
;
1590 node
= hctx
->numa_node
;
1591 if (node
== NUMA_NO_NODE
)
1592 node
= hctx
->numa_node
= set
->numa_node
;
1594 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1595 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1596 spin_lock_init(&hctx
->lock
);
1597 INIT_LIST_HEAD(&hctx
->dispatch
);
1599 hctx
->queue_num
= hctx_idx
;
1600 hctx
->flags
= set
->flags
;
1601 hctx
->cmd_size
= set
->cmd_size
;
1603 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1604 blk_mq_hctx_notify
, hctx
);
1605 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1607 hctx
->tags
= set
->tags
[hctx_idx
];
1610 * Allocate space for all possible cpus to avoid allocation at
1613 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1616 goto unregister_cpu_notifier
;
1618 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1623 if (set
->ops
->init_hctx
&&
1624 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
1627 hctx
->fq
= blk_alloc_flush_queue(q
, hctx
->numa_node
, set
->cmd_size
);
1631 if (set
->ops
->init_request
&&
1632 set
->ops
->init_request(set
->driver_data
,
1633 hctx
->fq
->flush_rq
, hctx_idx
,
1634 flush_start_tag
+ hctx_idx
, node
))
1642 if (set
->ops
->exit_hctx
)
1643 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1645 blk_mq_free_bitmap(&hctx
->ctx_map
);
1648 unregister_cpu_notifier
:
1649 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1654 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1655 struct blk_mq_tag_set
*set
)
1657 struct blk_mq_hw_ctx
*hctx
;
1661 * Initialize hardware queues
1663 queue_for_each_hw_ctx(q
, hctx
, i
) {
1664 if (blk_mq_init_hctx(q
, set
, hctx
, i
))
1668 if (i
== q
->nr_hw_queues
)
1674 blk_mq_exit_hw_queues(q
, set
, i
);
1679 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1680 unsigned int nr_hw_queues
)
1684 for_each_possible_cpu(i
) {
1685 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1686 struct blk_mq_hw_ctx
*hctx
;
1688 memset(__ctx
, 0, sizeof(*__ctx
));
1690 spin_lock_init(&__ctx
->lock
);
1691 INIT_LIST_HEAD(&__ctx
->rq_list
);
1694 /* If the cpu isn't online, the cpu is mapped to first hctx */
1698 hctx
= q
->mq_ops
->map_queue(q
, i
);
1699 cpumask_set_cpu(i
, hctx
->cpumask
);
1703 * Set local node, IFF we have more than one hw queue. If
1704 * not, we remain on the home node of the device
1706 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1707 hctx
->numa_node
= cpu_to_node(i
);
1711 static void blk_mq_map_swqueue(struct request_queue
*q
)
1714 struct blk_mq_hw_ctx
*hctx
;
1715 struct blk_mq_ctx
*ctx
;
1717 queue_for_each_hw_ctx(q
, hctx
, i
) {
1718 cpumask_clear(hctx
->cpumask
);
1723 * Map software to hardware queues
1725 queue_for_each_ctx(q
, ctx
, i
) {
1726 /* If the cpu isn't online, the cpu is mapped to first hctx */
1730 hctx
= q
->mq_ops
->map_queue(q
, i
);
1731 cpumask_set_cpu(i
, hctx
->cpumask
);
1732 ctx
->index_hw
= hctx
->nr_ctx
;
1733 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1736 queue_for_each_hw_ctx(q
, hctx
, i
) {
1738 * If no software queues are mapped to this hardware queue,
1739 * disable it and free the request entries.
1741 if (!hctx
->nr_ctx
) {
1742 struct blk_mq_tag_set
*set
= q
->tag_set
;
1745 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1746 set
->tags
[i
] = NULL
;
1753 * Initialize batch roundrobin counts
1755 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1756 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1760 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1762 struct blk_mq_hw_ctx
*hctx
;
1763 struct request_queue
*q
;
1767 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1772 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1773 blk_mq_freeze_queue(q
);
1775 queue_for_each_hw_ctx(q
, hctx
, i
) {
1777 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1779 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1781 blk_mq_unfreeze_queue(q
);
1785 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1787 struct blk_mq_tag_set
*set
= q
->tag_set
;
1789 mutex_lock(&set
->tag_list_lock
);
1790 list_del_init(&q
->tag_set_list
);
1791 blk_mq_update_tag_set_depth(set
);
1792 mutex_unlock(&set
->tag_list_lock
);
1795 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1796 struct request_queue
*q
)
1800 mutex_lock(&set
->tag_list_lock
);
1801 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1802 blk_mq_update_tag_set_depth(set
);
1803 mutex_unlock(&set
->tag_list_lock
);
1806 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1808 struct blk_mq_hw_ctx
**hctxs
;
1809 struct blk_mq_ctx __percpu
*ctx
;
1810 struct request_queue
*q
;
1814 ctx
= alloc_percpu(struct blk_mq_ctx
);
1816 return ERR_PTR(-ENOMEM
);
1819 * If a crashdump is active, then we are potentially in a very
1820 * memory constrained environment. Limit us to 1 queue and
1821 * 64 tags to prevent using too much memory.
1823 if (is_kdump_kernel()) {
1824 set
->nr_hw_queues
= 1;
1825 set
->queue_depth
= min(64U, set
->queue_depth
);
1828 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1834 map
= blk_mq_make_queue_map(set
);
1838 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1839 int node
= blk_mq_hw_queue_to_node(map
, i
);
1841 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1846 if (!zalloc_cpumask_var_node(&hctxs
[i
]->cpumask
, GFP_KERNEL
,
1850 atomic_set(&hctxs
[i
]->nr_active
, 0);
1851 hctxs
[i
]->numa_node
= node
;
1852 hctxs
[i
]->queue_num
= i
;
1855 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1860 * Init percpu_ref in atomic mode so that it's faster to shutdown.
1861 * See blk_register_queue() for details.
1863 if (percpu_ref_init(&q
->mq_usage_counter
, blk_mq_usage_counter_release
,
1864 PERCPU_REF_INIT_ATOMIC
, GFP_KERNEL
))
1867 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1868 blk_queue_rq_timeout(q
, 30000);
1870 q
->nr_queues
= nr_cpu_ids
;
1871 q
->nr_hw_queues
= set
->nr_hw_queues
;
1875 q
->queue_hw_ctx
= hctxs
;
1877 q
->mq_ops
= set
->ops
;
1878 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1880 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
1881 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
1883 q
->sg_reserved_size
= INT_MAX
;
1885 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1886 INIT_LIST_HEAD(&q
->requeue_list
);
1887 spin_lock_init(&q
->requeue_lock
);
1889 if (q
->nr_hw_queues
> 1)
1890 blk_queue_make_request(q
, blk_mq_make_request
);
1892 blk_queue_make_request(q
, blk_sq_make_request
);
1895 blk_queue_rq_timeout(q
, set
->timeout
);
1898 * Do this after blk_queue_make_request() overrides it...
1900 q
->nr_requests
= set
->queue_depth
;
1902 if (set
->ops
->complete
)
1903 blk_queue_softirq_done(q
, set
->ops
->complete
);
1905 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1907 if (blk_mq_init_hw_queues(q
, set
))
1910 mutex_lock(&all_q_mutex
);
1911 list_add_tail(&q
->all_q_node
, &all_q_list
);
1912 mutex_unlock(&all_q_mutex
);
1914 blk_mq_add_queue_tag_set(set
, q
);
1916 blk_mq_map_swqueue(q
);
1921 blk_cleanup_queue(q
);
1924 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1927 free_cpumask_var(hctxs
[i
]->cpumask
);
1934 return ERR_PTR(-ENOMEM
);
1936 EXPORT_SYMBOL(blk_mq_init_queue
);
1938 void blk_mq_free_queue(struct request_queue
*q
)
1940 struct blk_mq_tag_set
*set
= q
->tag_set
;
1942 blk_mq_del_queue_tag_set(q
);
1944 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1945 blk_mq_free_hw_queues(q
, set
);
1947 percpu_ref_exit(&q
->mq_usage_counter
);
1949 free_percpu(q
->queue_ctx
);
1950 kfree(q
->queue_hw_ctx
);
1953 q
->queue_ctx
= NULL
;
1954 q
->queue_hw_ctx
= NULL
;
1957 mutex_lock(&all_q_mutex
);
1958 list_del_init(&q
->all_q_node
);
1959 mutex_unlock(&all_q_mutex
);
1962 /* Basically redo blk_mq_init_queue with queue frozen */
1963 static void blk_mq_queue_reinit(struct request_queue
*q
)
1965 blk_mq_freeze_queue(q
);
1967 blk_mq_sysfs_unregister(q
);
1969 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1972 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1973 * we should change hctx numa_node according to new topology (this
1974 * involves free and re-allocate memory, worthy doing?)
1977 blk_mq_map_swqueue(q
);
1979 blk_mq_sysfs_register(q
);
1981 blk_mq_unfreeze_queue(q
);
1984 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1985 unsigned long action
, void *hcpu
)
1987 struct request_queue
*q
;
1990 * Before new mappings are established, hotadded cpu might already
1991 * start handling requests. This doesn't break anything as we map
1992 * offline CPUs to first hardware queue. We will re-init the queue
1993 * below to get optimal settings.
1995 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1996 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1999 mutex_lock(&all_q_mutex
);
2000 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2001 blk_mq_queue_reinit(q
);
2002 mutex_unlock(&all_q_mutex
);
2006 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2010 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2011 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
2020 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2026 * Allocate the request maps associated with this tag_set. Note that this
2027 * may reduce the depth asked for, if memory is tight. set->queue_depth
2028 * will be updated to reflect the allocated depth.
2030 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2035 depth
= set
->queue_depth
;
2037 err
= __blk_mq_alloc_rq_maps(set
);
2041 set
->queue_depth
>>= 1;
2042 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
2046 } while (set
->queue_depth
);
2048 if (!set
->queue_depth
|| err
) {
2049 pr_err("blk-mq: failed to allocate request map\n");
2053 if (depth
!= set
->queue_depth
)
2054 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2055 depth
, set
->queue_depth
);
2061 * Alloc a tag set to be associated with one or more request queues.
2062 * May fail with EINVAL for various error conditions. May adjust the
2063 * requested depth down, if if it too large. In that case, the set
2064 * value will be stored in set->queue_depth.
2066 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2068 if (!set
->nr_hw_queues
)
2070 if (!set
->queue_depth
)
2072 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2075 if (!set
->nr_hw_queues
|| !set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
2078 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2079 pr_info("blk-mq: reduced tag depth to %u\n",
2081 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2084 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
2085 sizeof(struct blk_mq_tags
*),
2086 GFP_KERNEL
, set
->numa_node
);
2090 if (blk_mq_alloc_rq_maps(set
))
2093 mutex_init(&set
->tag_list_lock
);
2094 INIT_LIST_HEAD(&set
->tag_list
);
2102 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2104 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2108 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2110 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2116 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2118 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2120 struct blk_mq_tag_set
*set
= q
->tag_set
;
2121 struct blk_mq_hw_ctx
*hctx
;
2124 if (!set
|| nr
> set
->queue_depth
)
2128 queue_for_each_hw_ctx(q
, hctx
, i
) {
2129 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2135 q
->nr_requests
= nr
;
2140 void blk_mq_disable_hotplug(void)
2142 mutex_lock(&all_q_mutex
);
2145 void blk_mq_enable_hotplug(void)
2147 mutex_unlock(&all_q_mutex
);
2150 static int __init
blk_mq_init(void)
2154 hotcpu_notifier(blk_mq_queue_reinit_notify
, 0);
2158 subsys_initcall(blk_mq_init
);