1 #include <linux/kernel.h>
2 #include <linux/module.h>
3 #include <linux/backing-dev.h>
5 #include <linux/blkdev.h>
7 #include <linux/init.h>
8 #include <linux/slab.h>
9 #include <linux/workqueue.h>
10 #include <linux/smp.h>
11 #include <linux/llist.h>
12 #include <linux/list_sort.h>
13 #include <linux/cpu.h>
14 #include <linux/cache.h>
15 #include <linux/sched/sysctl.h>
16 #include <linux/delay.h>
18 #include <trace/events/block.h>
20 #include <linux/blk-mq.h>
23 #include "blk-mq-tag.h"
25 static DEFINE_MUTEX(all_q_mutex
);
26 static LIST_HEAD(all_q_list
);
28 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
30 DEFINE_PER_CPU(struct llist_head
, ipi_lists
);
32 static struct blk_mq_ctx
*__blk_mq_get_ctx(struct request_queue
*q
,
35 return per_cpu_ptr(q
->queue_ctx
, cpu
);
39 * This assumes per-cpu software queueing queues. They could be per-node
40 * as well, for instance. For now this is hardcoded as-is. Note that we don't
41 * care about preemption, since we know the ctx's are persistent. This does
42 * mean that we can't rely on ctx always matching the currently running CPU.
44 static struct blk_mq_ctx
*blk_mq_get_ctx(struct request_queue
*q
)
46 return __blk_mq_get_ctx(q
, get_cpu());
49 static void blk_mq_put_ctx(struct blk_mq_ctx
*ctx
)
55 * Check if any of the ctx's have pending work in this hardware queue
57 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
61 for (i
= 0; i
< hctx
->nr_ctx_map
; i
++)
69 * Mark this ctx as having pending work in this hardware queue
71 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
72 struct blk_mq_ctx
*ctx
)
74 if (!test_bit(ctx
->index_hw
, hctx
->ctx_map
))
75 set_bit(ctx
->index_hw
, hctx
->ctx_map
);
78 static struct request
*blk_mq_alloc_rq(struct blk_mq_hw_ctx
*hctx
, gfp_t gfp
,
84 tag
= blk_mq_get_tag(hctx
->tags
, gfp
, reserved
);
85 if (tag
!= BLK_MQ_TAG_FAIL
) {
95 static int blk_mq_queue_enter(struct request_queue
*q
)
99 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
101 /* we have problems to freeze the queue if it's initializing */
102 if (!blk_queue_bypass(q
) || !blk_queue_init_done(q
))
105 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
107 spin_lock_irq(q
->queue_lock
);
108 ret
= wait_event_interruptible_lock_irq(q
->mq_freeze_wq
,
109 !blk_queue_bypass(q
), *q
->queue_lock
);
110 /* inc usage with lock hold to avoid freeze_queue runs here */
112 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
113 spin_unlock_irq(q
->queue_lock
);
118 static void blk_mq_queue_exit(struct request_queue
*q
)
120 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
124 * Guarantee no request is in use, so we can change any data structure of
125 * the queue afterward.
127 static void blk_mq_freeze_queue(struct request_queue
*q
)
131 spin_lock_irq(q
->queue_lock
);
132 drain
= !q
->bypass_depth
++;
133 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
134 spin_unlock_irq(q
->queue_lock
);
142 spin_lock_irq(q
->queue_lock
);
143 count
= percpu_counter_sum(&q
->mq_usage_counter
);
144 spin_unlock_irq(q
->queue_lock
);
148 blk_mq_run_queues(q
, false);
153 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
157 spin_lock_irq(q
->queue_lock
);
158 if (!--q
->bypass_depth
) {
159 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
162 WARN_ON_ONCE(q
->bypass_depth
< 0);
163 spin_unlock_irq(q
->queue_lock
);
165 wake_up_all(&q
->mq_freeze_wq
);
168 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
170 return blk_mq_has_free_tags(hctx
->tags
);
172 EXPORT_SYMBOL(blk_mq_can_queue
);
174 static void blk_mq_rq_ctx_init(struct blk_mq_ctx
*ctx
, struct request
*rq
,
175 unsigned int rw_flags
)
178 rq
->cmd_flags
= rw_flags
;
179 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
182 static struct request
*__blk_mq_alloc_request(struct blk_mq_hw_ctx
*hctx
,
183 gfp_t gfp
, bool reserved
)
185 return blk_mq_alloc_rq(hctx
, gfp
, reserved
);
188 static struct request
*blk_mq_alloc_request_pinned(struct request_queue
*q
,
195 struct blk_mq_ctx
*ctx
= blk_mq_get_ctx(q
);
196 struct blk_mq_hw_ctx
*hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
198 rq
= __blk_mq_alloc_request(hctx
, gfp
& ~__GFP_WAIT
, reserved
);
200 blk_mq_rq_ctx_init(ctx
, rq
, rw
);
202 } else if (!(gfp
& __GFP_WAIT
))
206 __blk_mq_run_hw_queue(hctx
);
207 blk_mq_wait_for_tags(hctx
->tags
);
213 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
,
214 gfp_t gfp
, bool reserved
)
218 if (blk_mq_queue_enter(q
))
221 rq
= blk_mq_alloc_request_pinned(q
, rw
, gfp
, reserved
);
222 blk_mq_put_ctx(rq
->mq_ctx
);
226 struct request
*blk_mq_alloc_reserved_request(struct request_queue
*q
, int rw
,
231 if (blk_mq_queue_enter(q
))
234 rq
= blk_mq_alloc_request_pinned(q
, rw
, gfp
, true);
235 blk_mq_put_ctx(rq
->mq_ctx
);
238 EXPORT_SYMBOL(blk_mq_alloc_reserved_request
);
241 * Re-init and set pdu, if we have it
243 static void blk_mq_rq_init(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
245 blk_rq_init(hctx
->queue
, rq
);
248 rq
->special
= blk_mq_rq_to_pdu(rq
);
251 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
252 struct blk_mq_ctx
*ctx
, struct request
*rq
)
254 const int tag
= rq
->tag
;
255 struct request_queue
*q
= rq
->q
;
257 blk_mq_rq_init(hctx
, rq
);
258 blk_mq_put_tag(hctx
->tags
, tag
);
260 blk_mq_queue_exit(q
);
263 void blk_mq_free_request(struct request
*rq
)
265 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
266 struct blk_mq_hw_ctx
*hctx
;
267 struct request_queue
*q
= rq
->q
;
269 ctx
->rq_completed
[rq_is_sync(rq
)]++;
271 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
272 __blk_mq_free_request(hctx
, ctx
, rq
);
275 static void blk_mq_bio_endio(struct request
*rq
, struct bio
*bio
, int error
)
278 clear_bit(BIO_UPTODATE
, &bio
->bi_flags
);
279 else if (!test_bit(BIO_UPTODATE
, &bio
->bi_flags
))
282 if (unlikely(rq
->cmd_flags
& REQ_QUIET
))
283 set_bit(BIO_QUIET
, &bio
->bi_flags
);
285 /* don't actually finish bio if it's part of flush sequence */
286 if (!(rq
->cmd_flags
& REQ_FLUSH_SEQ
))
287 bio_endio(bio
, error
);
290 void blk_mq_complete_request(struct request
*rq
, int error
)
292 struct bio
*bio
= rq
->bio
;
293 unsigned int bytes
= 0;
295 trace_block_rq_complete(rq
->q
, rq
);
298 struct bio
*next
= bio
->bi_next
;
301 bytes
+= bio
->bi_size
;
302 blk_mq_bio_endio(rq
, bio
, error
);
306 blk_account_io_completion(rq
, bytes
);
309 rq
->end_io(rq
, error
);
311 blk_mq_free_request(rq
);
313 blk_account_io_done(rq
);
316 void __blk_mq_end_io(struct request
*rq
, int error
)
318 if (!blk_mark_rq_complete(rq
))
319 blk_mq_complete_request(rq
, error
);
322 #if defined(CONFIG_SMP)
325 * Called with interrupts disabled.
327 static void ipi_end_io(void *data
)
329 struct llist_head
*list
= &per_cpu(ipi_lists
, smp_processor_id());
330 struct llist_node
*entry
, *next
;
333 entry
= llist_del_all(list
);
337 rq
= llist_entry(entry
, struct request
, ll_list
);
338 __blk_mq_end_io(rq
, rq
->errors
);
343 static int ipi_remote_cpu(struct blk_mq_ctx
*ctx
, const int cpu
,
344 struct request
*rq
, const int error
)
346 struct call_single_data
*data
= &rq
->csd
;
349 rq
->ll_list
.next
= NULL
;
352 * If the list is non-empty, an existing IPI must already
353 * be "in flight". If that is the case, we need not schedule
356 if (llist_add(&rq
->ll_list
, &per_cpu(ipi_lists
, ctx
->cpu
))) {
357 data
->func
= ipi_end_io
;
359 __smp_call_function_single(ctx
->cpu
, data
, 0);
364 #else /* CONFIG_SMP */
365 static int ipi_remote_cpu(struct blk_mq_ctx
*ctx
, const int cpu
,
366 struct request
*rq
, const int error
)
373 * End IO on this request on a multiqueue enabled driver. We'll either do
374 * it directly inline, or punt to a local IPI handler on the matching
377 void blk_mq_end_io(struct request
*rq
, int error
)
379 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
382 if (!ctx
->ipi_redirect
)
383 return __blk_mq_end_io(rq
, error
);
387 if (cpu
== ctx
->cpu
|| !cpu_online(ctx
->cpu
) ||
388 !ipi_remote_cpu(ctx
, cpu
, rq
, error
))
389 __blk_mq_end_io(rq
, error
);
393 EXPORT_SYMBOL(blk_mq_end_io
);
395 static void blk_mq_start_request(struct request
*rq
)
397 struct request_queue
*q
= rq
->q
;
399 trace_block_rq_issue(q
, rq
);
402 * Just mark start time and set the started bit. Due to memory
403 * ordering, we know we'll see the correct deadline as long as
404 * REQ_ATOMIC_STARTED is seen.
406 rq
->deadline
= jiffies
+ q
->rq_timeout
;
407 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
410 static void blk_mq_requeue_request(struct request
*rq
)
412 struct request_queue
*q
= rq
->q
;
414 trace_block_rq_requeue(q
, rq
);
415 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
418 struct blk_mq_timeout_data
{
419 struct blk_mq_hw_ctx
*hctx
;
421 unsigned int *next_set
;
424 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
426 struct blk_mq_timeout_data
*data
= __data
;
427 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
430 /* It may not be in flight yet (this is where
431 * the REQ_ATOMIC_STARTED flag comes in). The requests are
432 * statically allocated, so we know it's always safe to access the
433 * memory associated with a bit offset into ->rqs[].
439 tag
= find_next_zero_bit(free_tags
, hctx
->queue_depth
, tag
);
440 if (tag
>= hctx
->queue_depth
)
443 rq
= hctx
->rqs
[tag
++];
445 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
448 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
452 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
454 unsigned int *next_set
)
456 struct blk_mq_timeout_data data
= {
459 .next_set
= next_set
,
463 * Ask the tagging code to iterate busy requests, so we can
464 * check them for timeout.
466 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
469 static void blk_mq_rq_timer(unsigned long data
)
471 struct request_queue
*q
= (struct request_queue
*) data
;
472 struct blk_mq_hw_ctx
*hctx
;
473 unsigned long next
= 0;
476 queue_for_each_hw_ctx(q
, hctx
, i
)
477 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
480 mod_timer(&q
->timeout
, round_jiffies_up(next
));
484 * Reverse check our software queue for entries that we could potentially
485 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
486 * too much time checking for merges.
488 static bool blk_mq_attempt_merge(struct request_queue
*q
,
489 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
494 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
500 if (!blk_rq_merge_ok(rq
, bio
))
503 el_ret
= blk_try_merge(rq
, bio
);
504 if (el_ret
== ELEVATOR_BACK_MERGE
) {
505 if (bio_attempt_back_merge(q
, rq
, bio
)) {
510 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
511 if (bio_attempt_front_merge(q
, rq
, bio
)) {
522 void blk_mq_add_timer(struct request
*rq
)
524 __blk_add_timer(rq
, NULL
);
528 * Run this hardware queue, pulling any software queues mapped to it in.
529 * Note that this function currently has various problems around ordering
530 * of IO. In particular, we'd like FIFO behaviour on handling existing
531 * items on the hctx->dispatch list. Ignore that for now.
533 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
535 struct request_queue
*q
= hctx
->queue
;
536 struct blk_mq_ctx
*ctx
;
541 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->flags
)))
547 * Touch any software queue that has pending entries.
549 for_each_set_bit(bit
, hctx
->ctx_map
, hctx
->nr_ctx
) {
550 clear_bit(bit
, hctx
->ctx_map
);
551 ctx
= hctx
->ctxs
[bit
];
552 BUG_ON(bit
!= ctx
->index_hw
);
554 spin_lock(&ctx
->lock
);
555 list_splice_tail_init(&ctx
->rq_list
, &rq_list
);
556 spin_unlock(&ctx
->lock
);
560 * If we have previous entries on our dispatch list, grab them
561 * and stuff them at the front for more fair dispatch.
563 if (!list_empty_careful(&hctx
->dispatch
)) {
564 spin_lock(&hctx
->lock
);
565 if (!list_empty(&hctx
->dispatch
))
566 list_splice_init(&hctx
->dispatch
, &rq_list
);
567 spin_unlock(&hctx
->lock
);
571 * Delete and return all entries from our dispatch list
576 * Now process all the entries, sending them to the driver.
578 while (!list_empty(&rq_list
)) {
581 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
582 list_del_init(&rq
->queuelist
);
583 blk_mq_start_request(rq
);
586 * Last request in the series. Flag it as such, this
587 * enables drivers to know when IO should be kicked off,
588 * if they don't do it on a per-request basis.
590 * Note: the flag isn't the only condition drivers
591 * should do kick off. If drive is busy, the last
592 * request might not have the bit set.
594 if (list_empty(&rq_list
))
595 rq
->cmd_flags
|= REQ_END
;
597 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
599 case BLK_MQ_RQ_QUEUE_OK
:
602 case BLK_MQ_RQ_QUEUE_BUSY
:
604 * FIXME: we should have a mechanism to stop the queue
605 * like blk_stop_queue, otherwise we will waste cpu
608 list_add(&rq
->queuelist
, &rq_list
);
609 blk_mq_requeue_request(rq
);
612 pr_err("blk-mq: bad return on queue: %d\n", ret
);
614 case BLK_MQ_RQ_QUEUE_ERROR
:
615 blk_mq_end_io(rq
, rq
->errors
);
619 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
624 hctx
->dispatched
[0]++;
625 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
626 hctx
->dispatched
[ilog2(queued
) + 1]++;
629 * Any items that need requeuing? Stuff them into hctx->dispatch,
630 * that is where we will continue on next queue run.
632 if (!list_empty(&rq_list
)) {
633 spin_lock(&hctx
->lock
);
634 list_splice(&rq_list
, &hctx
->dispatch
);
635 spin_unlock(&hctx
->lock
);
639 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
641 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->flags
)))
645 __blk_mq_run_hw_queue(hctx
);
647 struct request_queue
*q
= hctx
->queue
;
649 kblockd_schedule_delayed_work(q
, &hctx
->delayed_work
, 0);
653 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
655 struct blk_mq_hw_ctx
*hctx
;
658 queue_for_each_hw_ctx(q
, hctx
, i
) {
659 if ((!blk_mq_hctx_has_pending(hctx
) &&
660 list_empty_careful(&hctx
->dispatch
)) ||
661 test_bit(BLK_MQ_S_STOPPED
, &hctx
->flags
))
664 blk_mq_run_hw_queue(hctx
, async
);
667 EXPORT_SYMBOL(blk_mq_run_queues
);
669 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
671 cancel_delayed_work(&hctx
->delayed_work
);
672 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
674 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
676 void blk_mq_stop_hw_queues(struct request_queue
*q
)
678 struct blk_mq_hw_ctx
*hctx
;
681 queue_for_each_hw_ctx(q
, hctx
, i
)
682 blk_mq_stop_hw_queue(hctx
);
684 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
686 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
688 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
689 __blk_mq_run_hw_queue(hctx
);
691 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
693 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
)
695 struct blk_mq_hw_ctx
*hctx
;
698 queue_for_each_hw_ctx(q
, hctx
, i
) {
699 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
702 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
703 blk_mq_run_hw_queue(hctx
, true);
706 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
708 static void blk_mq_work_fn(struct work_struct
*work
)
710 struct blk_mq_hw_ctx
*hctx
;
712 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delayed_work
.work
);
713 __blk_mq_run_hw_queue(hctx
);
716 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
719 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
721 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
722 blk_mq_hctx_mark_pending(hctx
, ctx
);
725 * We do this early, to ensure we are on the right CPU.
727 blk_mq_add_timer(rq
);
730 void blk_mq_insert_request(struct request_queue
*q
, struct request
*rq
,
733 struct blk_mq_hw_ctx
*hctx
;
734 struct blk_mq_ctx
*ctx
, *current_ctx
;
737 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
739 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
)) {
740 blk_insert_flush(rq
);
742 current_ctx
= blk_mq_get_ctx(q
);
744 if (!cpu_online(ctx
->cpu
)) {
746 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
749 spin_lock(&ctx
->lock
);
750 __blk_mq_insert_request(hctx
, rq
);
751 spin_unlock(&ctx
->lock
);
753 blk_mq_put_ctx(current_ctx
);
757 __blk_mq_run_hw_queue(hctx
);
759 EXPORT_SYMBOL(blk_mq_insert_request
);
762 * This is a special version of blk_mq_insert_request to bypass FLUSH request
763 * check. Should only be used internally.
765 void blk_mq_run_request(struct request
*rq
, bool run_queue
, bool async
)
767 struct request_queue
*q
= rq
->q
;
768 struct blk_mq_hw_ctx
*hctx
;
769 struct blk_mq_ctx
*ctx
, *current_ctx
;
771 current_ctx
= blk_mq_get_ctx(q
);
774 if (!cpu_online(ctx
->cpu
)) {
778 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
780 /* ctx->cpu might be offline */
781 spin_lock(&ctx
->lock
);
782 __blk_mq_insert_request(hctx
, rq
);
783 spin_unlock(&ctx
->lock
);
785 blk_mq_put_ctx(current_ctx
);
788 blk_mq_run_hw_queue(hctx
, async
);
791 static void blk_mq_insert_requests(struct request_queue
*q
,
792 struct blk_mq_ctx
*ctx
,
793 struct list_head
*list
,
798 struct blk_mq_hw_ctx
*hctx
;
799 struct blk_mq_ctx
*current_ctx
;
801 trace_block_unplug(q
, depth
, !from_schedule
);
803 current_ctx
= blk_mq_get_ctx(q
);
805 if (!cpu_online(ctx
->cpu
))
807 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
810 * preemption doesn't flush plug list, so it's possible ctx->cpu is
813 spin_lock(&ctx
->lock
);
814 while (!list_empty(list
)) {
817 rq
= list_first_entry(list
, struct request
, queuelist
);
818 list_del_init(&rq
->queuelist
);
820 __blk_mq_insert_request(hctx
, rq
);
822 spin_unlock(&ctx
->lock
);
824 blk_mq_put_ctx(current_ctx
);
826 blk_mq_run_hw_queue(hctx
, from_schedule
);
829 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
831 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
832 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
834 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
835 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
836 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
839 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
841 struct blk_mq_ctx
*this_ctx
;
842 struct request_queue
*this_q
;
848 list_splice_init(&plug
->mq_list
, &list
);
850 list_sort(NULL
, &list
, plug_ctx_cmp
);
856 while (!list_empty(&list
)) {
857 rq
= list_entry_rq(list
.next
);
858 list_del_init(&rq
->queuelist
);
860 if (rq
->mq_ctx
!= this_ctx
) {
862 blk_mq_insert_requests(this_q
, this_ctx
,
867 this_ctx
= rq
->mq_ctx
;
873 list_add_tail(&rq
->queuelist
, &ctx_list
);
877 * If 'this_ctx' is set, we know we have entries to complete
878 * on 'ctx_list'. Do those.
881 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
886 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
888 init_request_from_bio(rq
, bio
);
889 blk_account_io_start(rq
, 1);
892 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
894 struct blk_mq_hw_ctx
*hctx
;
895 struct blk_mq_ctx
*ctx
;
896 const int is_sync
= rw_is_sync(bio
->bi_rw
);
897 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
898 int rw
= bio_data_dir(bio
);
900 unsigned int use_plug
, request_count
= 0;
903 * If we have multiple hardware queues, just go directly to
904 * one of those for sync IO.
906 use_plug
= !is_flush_fua
&& ((q
->nr_hw_queues
== 1) || !is_sync
);
908 blk_queue_bounce(q
, &bio
);
910 if (use_plug
&& blk_attempt_plug_merge(q
, bio
, &request_count
))
913 if (blk_mq_queue_enter(q
)) {
914 bio_endio(bio
, -EIO
);
918 ctx
= blk_mq_get_ctx(q
);
919 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
921 trace_block_getrq(q
, bio
, rw
);
922 rq
= __blk_mq_alloc_request(hctx
, GFP_ATOMIC
, false);
924 blk_mq_rq_ctx_init(ctx
, rq
, rw
);
927 trace_block_sleeprq(q
, bio
, rw
);
928 rq
= blk_mq_alloc_request_pinned(q
, rw
, __GFP_WAIT
|GFP_ATOMIC
,
931 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
936 if (unlikely(is_flush_fua
)) {
937 blk_mq_bio_to_request(rq
, bio
);
939 blk_insert_flush(rq
);
944 * A task plug currently exists. Since this is completely lockless,
945 * utilize that to temporarily store requests until the task is
946 * either done or scheduled away.
949 struct blk_plug
*plug
= current
->plug
;
952 blk_mq_bio_to_request(rq
, bio
);
953 if (list_empty(&plug
->mq_list
))
955 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
956 blk_flush_plug_list(plug
, false);
959 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
965 spin_lock(&ctx
->lock
);
967 if ((hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
968 blk_mq_attempt_merge(q
, ctx
, bio
))
969 __blk_mq_free_request(hctx
, ctx
, rq
);
971 blk_mq_bio_to_request(rq
, bio
);
972 __blk_mq_insert_request(hctx
, rq
);
975 spin_unlock(&ctx
->lock
);
979 * For a SYNC request, send it to the hardware immediately. For an
980 * ASYNC request, just ensure that we run it later on. The latter
981 * allows for merging opportunities and more efficient dispatching.
984 blk_mq_run_hw_queue(hctx
, !is_sync
|| is_flush_fua
);
988 * Default mapping to a software queue, since we use one per CPU.
990 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
992 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
994 EXPORT_SYMBOL(blk_mq_map_queue
);
996 struct blk_mq_hw_ctx
*blk_mq_alloc_single_hw_queue(struct blk_mq_reg
*reg
,
997 unsigned int hctx_index
)
999 return kmalloc_node(sizeof(struct blk_mq_hw_ctx
),
1000 GFP_KERNEL
| __GFP_ZERO
, reg
->numa_node
);
1002 EXPORT_SYMBOL(blk_mq_alloc_single_hw_queue
);
1004 void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx
*hctx
,
1005 unsigned int hctx_index
)
1009 EXPORT_SYMBOL(blk_mq_free_single_hw_queue
);
1011 static void blk_mq_hctx_notify(void *data
, unsigned long action
,
1014 struct blk_mq_hw_ctx
*hctx
= data
;
1015 struct blk_mq_ctx
*ctx
;
1018 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
1022 * Move ctx entries to new CPU, if this one is going away.
1024 ctx
= __blk_mq_get_ctx(hctx
->queue
, cpu
);
1026 spin_lock(&ctx
->lock
);
1027 if (!list_empty(&ctx
->rq_list
)) {
1028 list_splice_init(&ctx
->rq_list
, &tmp
);
1029 clear_bit(ctx
->index_hw
, hctx
->ctx_map
);
1031 spin_unlock(&ctx
->lock
);
1033 if (list_empty(&tmp
))
1036 ctx
= blk_mq_get_ctx(hctx
->queue
);
1037 spin_lock(&ctx
->lock
);
1039 while (!list_empty(&tmp
)) {
1042 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1044 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1047 blk_mq_hctx_mark_pending(hctx
, ctx
);
1049 spin_unlock(&ctx
->lock
);
1050 blk_mq_put_ctx(ctx
);
1053 static void blk_mq_init_hw_commands(struct blk_mq_hw_ctx
*hctx
,
1054 void (*init
)(void *, struct blk_mq_hw_ctx
*,
1055 struct request
*, unsigned int),
1060 for (i
= 0; i
< hctx
->queue_depth
; i
++) {
1061 struct request
*rq
= hctx
->rqs
[i
];
1063 init(data
, hctx
, rq
, i
);
1067 void blk_mq_init_commands(struct request_queue
*q
,
1068 void (*init
)(void *, struct blk_mq_hw_ctx
*,
1069 struct request
*, unsigned int),
1072 struct blk_mq_hw_ctx
*hctx
;
1075 queue_for_each_hw_ctx(q
, hctx
, i
)
1076 blk_mq_init_hw_commands(hctx
, init
, data
);
1078 EXPORT_SYMBOL(blk_mq_init_commands
);
1080 static void blk_mq_free_rq_map(struct blk_mq_hw_ctx
*hctx
)
1084 while (!list_empty(&hctx
->page_list
)) {
1085 page
= list_first_entry(&hctx
->page_list
, struct page
, list
);
1086 list_del_init(&page
->list
);
1087 __free_pages(page
, page
->private);
1093 blk_mq_free_tags(hctx
->tags
);
1096 static size_t order_to_size(unsigned int order
)
1098 size_t ret
= PAGE_SIZE
;
1106 static int blk_mq_init_rq_map(struct blk_mq_hw_ctx
*hctx
,
1107 unsigned int reserved_tags
, int node
)
1109 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1110 size_t rq_size
, left
;
1112 INIT_LIST_HEAD(&hctx
->page_list
);
1114 hctx
->rqs
= kmalloc_node(hctx
->queue_depth
* sizeof(struct request
*),
1120 * rq_size is the size of the request plus driver payload, rounded
1121 * to the cacheline size
1123 rq_size
= round_up(sizeof(struct request
) + hctx
->cmd_size
,
1125 left
= rq_size
* hctx
->queue_depth
;
1127 for (i
= 0; i
< hctx
->queue_depth
;) {
1128 int this_order
= max_order
;
1133 while (left
< order_to_size(this_order
- 1) && this_order
)
1137 page
= alloc_pages_node(node
, GFP_KERNEL
, this_order
);
1142 if (order_to_size(this_order
) < rq_size
)
1149 page
->private = this_order
;
1150 list_add_tail(&page
->list
, &hctx
->page_list
);
1152 p
= page_address(page
);
1153 entries_per_page
= order_to_size(this_order
) / rq_size
;
1154 to_do
= min(entries_per_page
, hctx
->queue_depth
- i
);
1155 left
-= to_do
* rq_size
;
1156 for (j
= 0; j
< to_do
; j
++) {
1158 blk_mq_rq_init(hctx
, hctx
->rqs
[i
]);
1164 if (i
< (reserved_tags
+ BLK_MQ_TAG_MIN
))
1166 else if (i
!= hctx
->queue_depth
) {
1167 hctx
->queue_depth
= i
;
1168 pr_warn("%s: queue depth set to %u because of low memory\n",
1172 hctx
->tags
= blk_mq_init_tags(hctx
->queue_depth
, reserved_tags
, node
);
1175 blk_mq_free_rq_map(hctx
);
1182 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1183 struct blk_mq_reg
*reg
, void *driver_data
)
1185 struct blk_mq_hw_ctx
*hctx
;
1189 * Initialize hardware queues
1191 queue_for_each_hw_ctx(q
, hctx
, i
) {
1192 unsigned int num_maps
;
1195 node
= hctx
->numa_node
;
1196 if (node
== NUMA_NO_NODE
)
1197 node
= hctx
->numa_node
= reg
->numa_node
;
1199 INIT_DELAYED_WORK(&hctx
->delayed_work
, blk_mq_work_fn
);
1200 spin_lock_init(&hctx
->lock
);
1201 INIT_LIST_HEAD(&hctx
->dispatch
);
1203 hctx
->queue_num
= i
;
1204 hctx
->flags
= reg
->flags
;
1205 hctx
->queue_depth
= reg
->queue_depth
;
1206 hctx
->cmd_size
= reg
->cmd_size
;
1208 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1209 blk_mq_hctx_notify
, hctx
);
1210 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1212 if (blk_mq_init_rq_map(hctx
, reg
->reserved_tags
, node
))
1216 * Allocate space for all possible cpus to avoid allocation in
1219 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1224 num_maps
= ALIGN(nr_cpu_ids
, BITS_PER_LONG
) / BITS_PER_LONG
;
1225 hctx
->ctx_map
= kzalloc_node(num_maps
* sizeof(unsigned long),
1230 hctx
->nr_ctx_map
= num_maps
;
1233 if (reg
->ops
->init_hctx
&&
1234 reg
->ops
->init_hctx(hctx
, driver_data
, i
))
1238 if (i
== q
->nr_hw_queues
)
1244 queue_for_each_hw_ctx(q
, hctx
, j
) {
1248 if (reg
->ops
->exit_hctx
)
1249 reg
->ops
->exit_hctx(hctx
, j
);
1251 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1252 blk_mq_free_rq_map(hctx
);
1259 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1260 unsigned int nr_hw_queues
)
1264 for_each_possible_cpu(i
) {
1265 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1266 struct blk_mq_hw_ctx
*hctx
;
1268 memset(__ctx
, 0, sizeof(*__ctx
));
1270 spin_lock_init(&__ctx
->lock
);
1271 INIT_LIST_HEAD(&__ctx
->rq_list
);
1274 /* If the cpu isn't online, the cpu is mapped to first hctx */
1275 hctx
= q
->mq_ops
->map_queue(q
, i
);
1282 * Set local node, IFF we have more than one hw queue. If
1283 * not, we remain on the home node of the device
1285 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1286 hctx
->numa_node
= cpu_to_node(i
);
1290 static void blk_mq_map_swqueue(struct request_queue
*q
)
1293 struct blk_mq_hw_ctx
*hctx
;
1294 struct blk_mq_ctx
*ctx
;
1296 queue_for_each_hw_ctx(q
, hctx
, i
) {
1301 * Map software to hardware queues
1303 queue_for_each_ctx(q
, ctx
, i
) {
1304 /* If the cpu isn't online, the cpu is mapped to first hctx */
1305 hctx
= q
->mq_ops
->map_queue(q
, i
);
1306 ctx
->index_hw
= hctx
->nr_ctx
;
1307 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1311 struct request_queue
*blk_mq_init_queue(struct blk_mq_reg
*reg
,
1314 struct blk_mq_hw_ctx
**hctxs
;
1315 struct blk_mq_ctx
*ctx
;
1316 struct request_queue
*q
;
1319 if (!reg
->nr_hw_queues
||
1320 !reg
->ops
->queue_rq
|| !reg
->ops
->map_queue
||
1321 !reg
->ops
->alloc_hctx
|| !reg
->ops
->free_hctx
)
1322 return ERR_PTR(-EINVAL
);
1324 if (!reg
->queue_depth
)
1325 reg
->queue_depth
= BLK_MQ_MAX_DEPTH
;
1326 else if (reg
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
1327 pr_err("blk-mq: queuedepth too large (%u)\n", reg
->queue_depth
);
1328 reg
->queue_depth
= BLK_MQ_MAX_DEPTH
;
1332 * Set aside a tag for flush requests. It will only be used while
1333 * another flush request is in progress but outside the driver.
1335 * TODO: only allocate if flushes are supported
1338 reg
->reserved_tags
++;
1340 if (reg
->queue_depth
< (reg
->reserved_tags
+ BLK_MQ_TAG_MIN
))
1341 return ERR_PTR(-EINVAL
);
1343 ctx
= alloc_percpu(struct blk_mq_ctx
);
1345 return ERR_PTR(-ENOMEM
);
1347 hctxs
= kmalloc_node(reg
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1353 for (i
= 0; i
< reg
->nr_hw_queues
; i
++) {
1354 hctxs
[i
] = reg
->ops
->alloc_hctx(reg
, i
);
1358 hctxs
[i
]->numa_node
= NUMA_NO_NODE
;
1359 hctxs
[i
]->queue_num
= i
;
1362 q
= blk_alloc_queue_node(GFP_KERNEL
, reg
->numa_node
);
1366 q
->mq_map
= blk_mq_make_queue_map(reg
);
1370 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1371 blk_queue_rq_timeout(q
, 30000);
1373 q
->nr_queues
= nr_cpu_ids
;
1374 q
->nr_hw_queues
= reg
->nr_hw_queues
;
1377 q
->queue_hw_ctx
= hctxs
;
1379 q
->mq_ops
= reg
->ops
;
1381 blk_queue_make_request(q
, blk_mq_make_request
);
1382 blk_queue_rq_timed_out(q
, reg
->ops
->timeout
);
1384 blk_queue_rq_timeout(q
, reg
->timeout
);
1386 blk_mq_init_flush(q
);
1387 blk_mq_init_cpu_queues(q
, reg
->nr_hw_queues
);
1389 if (blk_mq_init_hw_queues(q
, reg
, driver_data
))
1392 blk_mq_map_swqueue(q
);
1394 mutex_lock(&all_q_mutex
);
1395 list_add_tail(&q
->all_q_node
, &all_q_list
);
1396 mutex_unlock(&all_q_mutex
);
1402 blk_cleanup_queue(q
);
1404 for (i
= 0; i
< reg
->nr_hw_queues
; i
++) {
1407 reg
->ops
->free_hctx(hctxs
[i
], i
);
1412 return ERR_PTR(-ENOMEM
);
1414 EXPORT_SYMBOL(blk_mq_init_queue
);
1416 void blk_mq_free_queue(struct request_queue
*q
)
1418 struct blk_mq_hw_ctx
*hctx
;
1421 queue_for_each_hw_ctx(q
, hctx
, i
) {
1422 cancel_delayed_work_sync(&hctx
->delayed_work
);
1423 kfree(hctx
->ctx_map
);
1425 blk_mq_free_rq_map(hctx
);
1426 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1427 if (q
->mq_ops
->exit_hctx
)
1428 q
->mq_ops
->exit_hctx(hctx
, i
);
1429 q
->mq_ops
->free_hctx(hctx
, i
);
1432 free_percpu(q
->queue_ctx
);
1433 kfree(q
->queue_hw_ctx
);
1436 q
->queue_ctx
= NULL
;
1437 q
->queue_hw_ctx
= NULL
;
1440 mutex_lock(&all_q_mutex
);
1441 list_del_init(&q
->all_q_node
);
1442 mutex_unlock(&all_q_mutex
);
1444 EXPORT_SYMBOL(blk_mq_free_queue
);
1446 /* Basically redo blk_mq_init_queue with queue frozen */
1447 static void blk_mq_queue_reinit(struct request_queue
*q
)
1449 blk_mq_freeze_queue(q
);
1451 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1454 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1455 * we should change hctx numa_node according to new topology (this
1456 * involves free and re-allocate memory, worthy doing?)
1459 blk_mq_map_swqueue(q
);
1461 blk_mq_unfreeze_queue(q
);
1464 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1465 unsigned long action
, void *hcpu
)
1467 struct request_queue
*q
;
1470 * Before new mapping is established, hotadded cpu might already start
1471 * handling requests. This doesn't break anything as we map offline
1472 * CPUs to first hardware queue. We will re-init queue below to get
1475 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1476 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1479 mutex_lock(&all_q_mutex
);
1480 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1481 blk_mq_queue_reinit(q
);
1482 mutex_unlock(&all_q_mutex
);
1486 static int __init
blk_mq_init(void)
1490 for_each_possible_cpu(i
)
1491 init_llist_head(&per_cpu(ipi_lists
, i
));
1495 /* Must be called after percpu_counter_hotcpu_callback() */
1496 hotcpu_notifier(blk_mq_queue_reinit_notify
, -10);
1500 subsys_initcall(blk_mq_init
);