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 static struct blk_mq_ctx
*__blk_mq_get_ctx(struct request_queue
*q
,
33 return per_cpu_ptr(q
->queue_ctx
, cpu
);
37 * This assumes per-cpu software queueing queues. They could be per-node
38 * as well, for instance. For now this is hardcoded as-is. Note that we don't
39 * care about preemption, since we know the ctx's are persistent. This does
40 * mean that we can't rely on ctx always matching the currently running CPU.
42 static struct blk_mq_ctx
*blk_mq_get_ctx(struct request_queue
*q
)
44 return __blk_mq_get_ctx(q
, get_cpu());
47 static void blk_mq_put_ctx(struct blk_mq_ctx
*ctx
)
53 * Check if any of the ctx's have pending work in this hardware queue
55 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
59 for (i
= 0; i
< hctx
->nr_ctx_map
; i
++)
67 * Mark this ctx as having pending work in this hardware queue
69 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
70 struct blk_mq_ctx
*ctx
)
72 if (!test_bit(ctx
->index_hw
, hctx
->ctx_map
))
73 set_bit(ctx
->index_hw
, hctx
->ctx_map
);
76 static struct request
*__blk_mq_alloc_request(struct blk_mq_hw_ctx
*hctx
,
77 gfp_t gfp
, bool reserved
)
82 tag
= blk_mq_get_tag(hctx
->tags
, gfp
, reserved
);
83 if (tag
!= BLK_MQ_TAG_FAIL
) {
93 static int blk_mq_queue_enter(struct request_queue
*q
)
97 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
99 /* we have problems to freeze the queue if it's initializing */
100 if (!blk_queue_bypass(q
) || !blk_queue_init_done(q
))
103 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
105 spin_lock_irq(q
->queue_lock
);
106 ret
= wait_event_interruptible_lock_irq(q
->mq_freeze_wq
,
107 !blk_queue_bypass(q
) || blk_queue_dying(q
),
109 /* inc usage with lock hold to avoid freeze_queue runs here */
110 if (!ret
&& !blk_queue_dying(q
))
111 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
112 else if (blk_queue_dying(q
))
114 spin_unlock_irq(q
->queue_lock
);
119 static void blk_mq_queue_exit(struct request_queue
*q
)
121 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
124 static void __blk_mq_drain_queue(struct request_queue
*q
)
129 spin_lock_irq(q
->queue_lock
);
130 count
= percpu_counter_sum(&q
->mq_usage_counter
);
131 spin_unlock_irq(q
->queue_lock
);
135 blk_mq_run_queues(q
, false);
141 * Guarantee no request is in use, so we can change any data structure of
142 * the queue afterward.
144 static void blk_mq_freeze_queue(struct request_queue
*q
)
148 spin_lock_irq(q
->queue_lock
);
149 drain
= !q
->bypass_depth
++;
150 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
151 spin_unlock_irq(q
->queue_lock
);
154 __blk_mq_drain_queue(q
);
157 void blk_mq_drain_queue(struct request_queue
*q
)
159 __blk_mq_drain_queue(q
);
162 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
166 spin_lock_irq(q
->queue_lock
);
167 if (!--q
->bypass_depth
) {
168 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
171 WARN_ON_ONCE(q
->bypass_depth
< 0);
172 spin_unlock_irq(q
->queue_lock
);
174 wake_up_all(&q
->mq_freeze_wq
);
177 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
179 return blk_mq_has_free_tags(hctx
->tags
);
181 EXPORT_SYMBOL(blk_mq_can_queue
);
183 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
184 struct request
*rq
, unsigned int rw_flags
)
186 if (blk_queue_io_stat(q
))
187 rw_flags
|= REQ_IO_STAT
;
190 rq
->cmd_flags
= rw_flags
;
191 rq
->start_time
= jiffies
;
192 set_start_time_ns(rq
);
193 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
196 static struct request
*blk_mq_alloc_request_pinned(struct request_queue
*q
,
203 struct blk_mq_ctx
*ctx
= blk_mq_get_ctx(q
);
204 struct blk_mq_hw_ctx
*hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
206 rq
= __blk_mq_alloc_request(hctx
, gfp
& ~__GFP_WAIT
, reserved
);
208 blk_mq_rq_ctx_init(q
, ctx
, rq
, rw
);
213 if (!(gfp
& __GFP_WAIT
))
216 __blk_mq_run_hw_queue(hctx
);
217 blk_mq_wait_for_tags(hctx
->tags
);
223 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
)
227 if (blk_mq_queue_enter(q
))
230 rq
= blk_mq_alloc_request_pinned(q
, rw
, gfp
, false);
232 blk_mq_put_ctx(rq
->mq_ctx
);
236 struct request
*blk_mq_alloc_reserved_request(struct request_queue
*q
, int rw
,
241 if (blk_mq_queue_enter(q
))
244 rq
= blk_mq_alloc_request_pinned(q
, rw
, gfp
, true);
246 blk_mq_put_ctx(rq
->mq_ctx
);
249 EXPORT_SYMBOL(blk_mq_alloc_reserved_request
);
252 * Re-init and set pdu, if we have it
254 void blk_mq_rq_init(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
256 blk_rq_init(hctx
->queue
, rq
);
259 rq
->special
= blk_mq_rq_to_pdu(rq
);
262 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
263 struct blk_mq_ctx
*ctx
, struct request
*rq
)
265 const int tag
= rq
->tag
;
266 struct request_queue
*q
= rq
->q
;
268 blk_mq_rq_init(hctx
, rq
);
269 blk_mq_put_tag(hctx
->tags
, tag
);
271 blk_mq_queue_exit(q
);
274 void blk_mq_free_request(struct request
*rq
)
276 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
277 struct blk_mq_hw_ctx
*hctx
;
278 struct request_queue
*q
= rq
->q
;
280 ctx
->rq_completed
[rq_is_sync(rq
)]++;
282 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
283 __blk_mq_free_request(hctx
, ctx
, rq
);
286 bool blk_mq_end_io_partial(struct request
*rq
, int error
, unsigned int nr_bytes
)
288 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
291 blk_account_io_done(rq
);
294 rq
->end_io(rq
, error
);
296 blk_mq_free_request(rq
);
299 EXPORT_SYMBOL(blk_mq_end_io_partial
);
301 static void __blk_mq_complete_request_remote(void *data
)
303 struct request
*rq
= data
;
305 rq
->q
->softirq_done_fn(rq
);
308 void __blk_mq_complete_request(struct request
*rq
)
310 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
313 if (!ctx
->ipi_redirect
) {
314 rq
->q
->softirq_done_fn(rq
);
319 if (cpu
!= ctx
->cpu
&& cpu_online(ctx
->cpu
)) {
320 rq
->csd
.func
= __blk_mq_complete_request_remote
;
323 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
325 rq
->q
->softirq_done_fn(rq
);
331 * blk_mq_complete_request - end I/O on a request
332 * @rq: the request being processed
335 * Ends all I/O on a request. It does not handle partial completions.
336 * The actual completion happens out-of-order, through a IPI handler.
338 void blk_mq_complete_request(struct request
*rq
)
340 if (unlikely(blk_should_fake_timeout(rq
->q
)))
342 if (!blk_mark_rq_complete(rq
))
343 __blk_mq_complete_request(rq
);
345 EXPORT_SYMBOL(blk_mq_complete_request
);
347 static void blk_mq_start_request(struct request
*rq
, bool last
)
349 struct request_queue
*q
= rq
->q
;
351 trace_block_rq_issue(q
, rq
);
354 * Just mark start time and set the started bit. Due to memory
355 * ordering, we know we'll see the correct deadline as long as
356 * REQ_ATOMIC_STARTED is seen.
358 rq
->deadline
= jiffies
+ q
->rq_timeout
;
359 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
361 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
363 * Make sure space for the drain appears. We know we can do
364 * this because max_hw_segments has been adjusted to be one
365 * fewer than the device can handle.
367 rq
->nr_phys_segments
++;
371 * Flag the last request in the series so that drivers know when IO
372 * should be kicked off, if they don't do it on a per-request basis.
374 * Note: the flag isn't the only condition drivers should do kick off.
375 * If drive is busy, the last request might not have the bit set.
378 rq
->cmd_flags
|= REQ_END
;
381 static void blk_mq_requeue_request(struct request
*rq
)
383 struct request_queue
*q
= rq
->q
;
385 trace_block_rq_requeue(q
, rq
);
386 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
388 rq
->cmd_flags
&= ~REQ_END
;
390 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
391 rq
->nr_phys_segments
--;
394 struct blk_mq_timeout_data
{
395 struct blk_mq_hw_ctx
*hctx
;
397 unsigned int *next_set
;
400 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
402 struct blk_mq_timeout_data
*data
= __data
;
403 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
406 /* It may not be in flight yet (this is where
407 * the REQ_ATOMIC_STARTED flag comes in). The requests are
408 * statically allocated, so we know it's always safe to access the
409 * memory associated with a bit offset into ->rqs[].
415 tag
= find_next_zero_bit(free_tags
, hctx
->queue_depth
, tag
);
416 if (tag
>= hctx
->queue_depth
)
419 rq
= hctx
->rqs
[tag
++];
421 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
424 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
428 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
430 unsigned int *next_set
)
432 struct blk_mq_timeout_data data
= {
435 .next_set
= next_set
,
439 * Ask the tagging code to iterate busy requests, so we can
440 * check them for timeout.
442 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
445 static void blk_mq_rq_timer(unsigned long data
)
447 struct request_queue
*q
= (struct request_queue
*) data
;
448 struct blk_mq_hw_ctx
*hctx
;
449 unsigned long next
= 0;
452 queue_for_each_hw_ctx(q
, hctx
, i
)
453 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
456 mod_timer(&q
->timeout
, round_jiffies_up(next
));
460 * Reverse check our software queue for entries that we could potentially
461 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
462 * too much time checking for merges.
464 static bool blk_mq_attempt_merge(struct request_queue
*q
,
465 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
470 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
476 if (!blk_rq_merge_ok(rq
, bio
))
479 el_ret
= blk_try_merge(rq
, bio
);
480 if (el_ret
== ELEVATOR_BACK_MERGE
) {
481 if (bio_attempt_back_merge(q
, rq
, bio
)) {
486 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
487 if (bio_attempt_front_merge(q
, rq
, bio
)) {
498 void blk_mq_add_timer(struct request
*rq
)
500 __blk_add_timer(rq
, NULL
);
504 * Run this hardware queue, pulling any software queues mapped to it in.
505 * Note that this function currently has various problems around ordering
506 * of IO. In particular, we'd like FIFO behaviour on handling existing
507 * items on the hctx->dispatch list. Ignore that for now.
509 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
511 struct request_queue
*q
= hctx
->queue
;
512 struct blk_mq_ctx
*ctx
;
517 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
523 * Touch any software queue that has pending entries.
525 for_each_set_bit(bit
, hctx
->ctx_map
, hctx
->nr_ctx
) {
526 clear_bit(bit
, hctx
->ctx_map
);
527 ctx
= hctx
->ctxs
[bit
];
528 BUG_ON(bit
!= ctx
->index_hw
);
530 spin_lock(&ctx
->lock
);
531 list_splice_tail_init(&ctx
->rq_list
, &rq_list
);
532 spin_unlock(&ctx
->lock
);
536 * If we have previous entries on our dispatch list, grab them
537 * and stuff them at the front for more fair dispatch.
539 if (!list_empty_careful(&hctx
->dispatch
)) {
540 spin_lock(&hctx
->lock
);
541 if (!list_empty(&hctx
->dispatch
))
542 list_splice_init(&hctx
->dispatch
, &rq_list
);
543 spin_unlock(&hctx
->lock
);
547 * Delete and return all entries from our dispatch list
552 * Now process all the entries, sending them to the driver.
554 while (!list_empty(&rq_list
)) {
557 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
558 list_del_init(&rq
->queuelist
);
560 blk_mq_start_request(rq
, list_empty(&rq_list
));
562 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
564 case BLK_MQ_RQ_QUEUE_OK
:
567 case BLK_MQ_RQ_QUEUE_BUSY
:
569 * FIXME: we should have a mechanism to stop the queue
570 * like blk_stop_queue, otherwise we will waste cpu
573 list_add(&rq
->queuelist
, &rq_list
);
574 blk_mq_requeue_request(rq
);
577 pr_err("blk-mq: bad return on queue: %d\n", ret
);
578 case BLK_MQ_RQ_QUEUE_ERROR
:
580 blk_mq_end_io(rq
, rq
->errors
);
584 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
589 hctx
->dispatched
[0]++;
590 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
591 hctx
->dispatched
[ilog2(queued
) + 1]++;
594 * Any items that need requeuing? Stuff them into hctx->dispatch,
595 * that is where we will continue on next queue run.
597 if (!list_empty(&rq_list
)) {
598 spin_lock(&hctx
->lock
);
599 list_splice(&rq_list
, &hctx
->dispatch
);
600 spin_unlock(&hctx
->lock
);
604 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
606 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
610 __blk_mq_run_hw_queue(hctx
);
612 kblockd_schedule_delayed_work(&hctx
->delayed_work
, 0);
615 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
617 struct blk_mq_hw_ctx
*hctx
;
620 queue_for_each_hw_ctx(q
, hctx
, i
) {
621 if ((!blk_mq_hctx_has_pending(hctx
) &&
622 list_empty_careful(&hctx
->dispatch
)) ||
623 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
626 blk_mq_run_hw_queue(hctx
, async
);
629 EXPORT_SYMBOL(blk_mq_run_queues
);
631 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
633 cancel_delayed_work(&hctx
->delayed_work
);
634 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
636 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
638 void blk_mq_stop_hw_queues(struct request_queue
*q
)
640 struct blk_mq_hw_ctx
*hctx
;
643 queue_for_each_hw_ctx(q
, hctx
, i
)
644 blk_mq_stop_hw_queue(hctx
);
646 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
648 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
650 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
651 __blk_mq_run_hw_queue(hctx
);
653 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
655 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
)
657 struct blk_mq_hw_ctx
*hctx
;
660 queue_for_each_hw_ctx(q
, hctx
, i
) {
661 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
664 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
665 blk_mq_run_hw_queue(hctx
, true);
668 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
670 static void blk_mq_work_fn(struct work_struct
*work
)
672 struct blk_mq_hw_ctx
*hctx
;
674 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delayed_work
.work
);
675 __blk_mq_run_hw_queue(hctx
);
678 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
679 struct request
*rq
, bool at_head
)
681 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
683 trace_block_rq_insert(hctx
->queue
, rq
);
686 list_add(&rq
->queuelist
, &ctx
->rq_list
);
688 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
689 blk_mq_hctx_mark_pending(hctx
, ctx
);
692 * We do this early, to ensure we are on the right CPU.
694 blk_mq_add_timer(rq
);
697 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
700 struct request_queue
*q
= rq
->q
;
701 struct blk_mq_hw_ctx
*hctx
;
702 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
704 current_ctx
= blk_mq_get_ctx(q
);
705 if (!cpu_online(ctx
->cpu
))
706 rq
->mq_ctx
= ctx
= current_ctx
;
708 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
710 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
) &&
711 !(rq
->cmd_flags
& (REQ_FLUSH_SEQ
))) {
712 blk_insert_flush(rq
);
714 spin_lock(&ctx
->lock
);
715 __blk_mq_insert_request(hctx
, rq
, at_head
);
716 spin_unlock(&ctx
->lock
);
719 blk_mq_put_ctx(current_ctx
);
722 blk_mq_run_hw_queue(hctx
, async
);
725 static void blk_mq_insert_requests(struct request_queue
*q
,
726 struct blk_mq_ctx
*ctx
,
727 struct list_head
*list
,
732 struct blk_mq_hw_ctx
*hctx
;
733 struct blk_mq_ctx
*current_ctx
;
735 trace_block_unplug(q
, depth
, !from_schedule
);
737 current_ctx
= blk_mq_get_ctx(q
);
739 if (!cpu_online(ctx
->cpu
))
741 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
744 * preemption doesn't flush plug list, so it's possible ctx->cpu is
747 spin_lock(&ctx
->lock
);
748 while (!list_empty(list
)) {
751 rq
= list_first_entry(list
, struct request
, queuelist
);
752 list_del_init(&rq
->queuelist
);
754 __blk_mq_insert_request(hctx
, rq
, false);
756 spin_unlock(&ctx
->lock
);
758 blk_mq_put_ctx(current_ctx
);
760 blk_mq_run_hw_queue(hctx
, from_schedule
);
763 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
765 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
766 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
768 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
769 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
770 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
773 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
775 struct blk_mq_ctx
*this_ctx
;
776 struct request_queue
*this_q
;
782 list_splice_init(&plug
->mq_list
, &list
);
784 list_sort(NULL
, &list
, plug_ctx_cmp
);
790 while (!list_empty(&list
)) {
791 rq
= list_entry_rq(list
.next
);
792 list_del_init(&rq
->queuelist
);
794 if (rq
->mq_ctx
!= this_ctx
) {
796 blk_mq_insert_requests(this_q
, this_ctx
,
801 this_ctx
= rq
->mq_ctx
;
807 list_add_tail(&rq
->queuelist
, &ctx_list
);
811 * If 'this_ctx' is set, we know we have entries to complete
812 * on 'ctx_list'. Do those.
815 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
820 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
822 init_request_from_bio(rq
, bio
);
823 blk_account_io_start(rq
, 1);
826 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
828 struct blk_mq_hw_ctx
*hctx
;
829 struct blk_mq_ctx
*ctx
;
830 const int is_sync
= rw_is_sync(bio
->bi_rw
);
831 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
832 int rw
= bio_data_dir(bio
);
834 unsigned int use_plug
, request_count
= 0;
837 * If we have multiple hardware queues, just go directly to
838 * one of those for sync IO.
840 use_plug
= !is_flush_fua
&& ((q
->nr_hw_queues
== 1) || !is_sync
);
842 blk_queue_bounce(q
, &bio
);
844 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
845 bio_endio(bio
, -EIO
);
849 if (use_plug
&& blk_attempt_plug_merge(q
, bio
, &request_count
))
852 if (blk_mq_queue_enter(q
)) {
853 bio_endio(bio
, -EIO
);
857 ctx
= blk_mq_get_ctx(q
);
858 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
862 trace_block_getrq(q
, bio
, rw
);
863 rq
= __blk_mq_alloc_request(hctx
, GFP_ATOMIC
, false);
865 blk_mq_rq_ctx_init(q
, ctx
, rq
, rw
);
868 trace_block_sleeprq(q
, bio
, rw
);
869 rq
= blk_mq_alloc_request_pinned(q
, rw
, __GFP_WAIT
|GFP_ATOMIC
,
872 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
877 if (unlikely(is_flush_fua
)) {
878 blk_mq_bio_to_request(rq
, bio
);
880 blk_insert_flush(rq
);
885 * A task plug currently exists. Since this is completely lockless,
886 * utilize that to temporarily store requests until the task is
887 * either done or scheduled away.
890 struct blk_plug
*plug
= current
->plug
;
893 blk_mq_bio_to_request(rq
, bio
);
894 if (list_empty(&plug
->mq_list
))
896 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
897 blk_flush_plug_list(plug
, false);
900 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
906 spin_lock(&ctx
->lock
);
908 if ((hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
909 blk_mq_attempt_merge(q
, ctx
, bio
))
910 __blk_mq_free_request(hctx
, ctx
, rq
);
912 blk_mq_bio_to_request(rq
, bio
);
913 __blk_mq_insert_request(hctx
, rq
, false);
916 spin_unlock(&ctx
->lock
);
920 * For a SYNC request, send it to the hardware immediately. For an
921 * ASYNC request, just ensure that we run it later on. The latter
922 * allows for merging opportunities and more efficient dispatching.
925 blk_mq_run_hw_queue(hctx
, !is_sync
|| is_flush_fua
);
929 * Default mapping to a software queue, since we use one per CPU.
931 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
933 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
935 EXPORT_SYMBOL(blk_mq_map_queue
);
937 struct blk_mq_hw_ctx
*blk_mq_alloc_single_hw_queue(struct blk_mq_reg
*reg
,
938 unsigned int hctx_index
)
940 return kmalloc_node(sizeof(struct blk_mq_hw_ctx
),
941 GFP_KERNEL
| __GFP_ZERO
, reg
->numa_node
);
943 EXPORT_SYMBOL(blk_mq_alloc_single_hw_queue
);
945 void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx
*hctx
,
946 unsigned int hctx_index
)
950 EXPORT_SYMBOL(blk_mq_free_single_hw_queue
);
952 static void blk_mq_hctx_notify(void *data
, unsigned long action
,
955 struct blk_mq_hw_ctx
*hctx
= data
;
956 struct request_queue
*q
= hctx
->queue
;
957 struct blk_mq_ctx
*ctx
;
960 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
)
964 * Move ctx entries to new CPU, if this one is going away.
966 ctx
= __blk_mq_get_ctx(q
, cpu
);
968 spin_lock(&ctx
->lock
);
969 if (!list_empty(&ctx
->rq_list
)) {
970 list_splice_init(&ctx
->rq_list
, &tmp
);
971 clear_bit(ctx
->index_hw
, hctx
->ctx_map
);
973 spin_unlock(&ctx
->lock
);
975 if (list_empty(&tmp
))
978 ctx
= blk_mq_get_ctx(q
);
979 spin_lock(&ctx
->lock
);
981 while (!list_empty(&tmp
)) {
984 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
986 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
989 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
990 blk_mq_hctx_mark_pending(hctx
, ctx
);
992 spin_unlock(&ctx
->lock
);
995 blk_mq_run_hw_queue(hctx
, true);
998 static int blk_mq_init_hw_commands(struct blk_mq_hw_ctx
*hctx
,
999 int (*init
)(void *, struct blk_mq_hw_ctx
*,
1000 struct request
*, unsigned int),
1006 for (i
= 0; i
< hctx
->queue_depth
; i
++) {
1007 struct request
*rq
= hctx
->rqs
[i
];
1009 ret
= init(data
, hctx
, rq
, i
);
1017 int blk_mq_init_commands(struct request_queue
*q
,
1018 int (*init
)(void *, struct blk_mq_hw_ctx
*,
1019 struct request
*, unsigned int),
1022 struct blk_mq_hw_ctx
*hctx
;
1026 queue_for_each_hw_ctx(q
, hctx
, i
) {
1027 ret
= blk_mq_init_hw_commands(hctx
, init
, data
);
1034 EXPORT_SYMBOL(blk_mq_init_commands
);
1036 static void blk_mq_free_hw_commands(struct blk_mq_hw_ctx
*hctx
,
1037 void (*free
)(void *, struct blk_mq_hw_ctx
*,
1038 struct request
*, unsigned int),
1043 for (i
= 0; i
< hctx
->queue_depth
; i
++) {
1044 struct request
*rq
= hctx
->rqs
[i
];
1046 free(data
, hctx
, rq
, i
);
1050 void blk_mq_free_commands(struct request_queue
*q
,
1051 void (*free
)(void *, struct blk_mq_hw_ctx
*,
1052 struct request
*, unsigned int),
1055 struct blk_mq_hw_ctx
*hctx
;
1058 queue_for_each_hw_ctx(q
, hctx
, i
)
1059 blk_mq_free_hw_commands(hctx
, free
, data
);
1061 EXPORT_SYMBOL(blk_mq_free_commands
);
1063 static void blk_mq_free_rq_map(struct blk_mq_hw_ctx
*hctx
)
1067 while (!list_empty(&hctx
->page_list
)) {
1068 page
= list_first_entry(&hctx
->page_list
, struct page
, lru
);
1069 list_del_init(&page
->lru
);
1070 __free_pages(page
, page
->private);
1076 blk_mq_free_tags(hctx
->tags
);
1079 static size_t order_to_size(unsigned int order
)
1081 size_t ret
= PAGE_SIZE
;
1089 static int blk_mq_init_rq_map(struct blk_mq_hw_ctx
*hctx
,
1090 unsigned int reserved_tags
, int node
)
1092 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1093 size_t rq_size
, left
;
1095 INIT_LIST_HEAD(&hctx
->page_list
);
1097 hctx
->rqs
= kmalloc_node(hctx
->queue_depth
* sizeof(struct request
*),
1103 * rq_size is the size of the request plus driver payload, rounded
1104 * to the cacheline size
1106 rq_size
= round_up(sizeof(struct request
) + hctx
->cmd_size
,
1108 left
= rq_size
* hctx
->queue_depth
;
1110 for (i
= 0; i
< hctx
->queue_depth
;) {
1111 int this_order
= max_order
;
1116 while (left
< order_to_size(this_order
- 1) && this_order
)
1120 page
= alloc_pages_node(node
, GFP_KERNEL
, this_order
);
1125 if (order_to_size(this_order
) < rq_size
)
1132 page
->private = this_order
;
1133 list_add_tail(&page
->lru
, &hctx
->page_list
);
1135 p
= page_address(page
);
1136 entries_per_page
= order_to_size(this_order
) / rq_size
;
1137 to_do
= min(entries_per_page
, hctx
->queue_depth
- i
);
1138 left
-= to_do
* rq_size
;
1139 for (j
= 0; j
< to_do
; j
++) {
1141 blk_mq_rq_init(hctx
, hctx
->rqs
[i
]);
1147 if (i
< (reserved_tags
+ BLK_MQ_TAG_MIN
))
1149 else if (i
!= hctx
->queue_depth
) {
1150 hctx
->queue_depth
= i
;
1151 pr_warn("%s: queue depth set to %u because of low memory\n",
1155 hctx
->tags
= blk_mq_init_tags(hctx
->queue_depth
, reserved_tags
, node
);
1158 blk_mq_free_rq_map(hctx
);
1165 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1166 struct blk_mq_reg
*reg
, void *driver_data
)
1168 struct blk_mq_hw_ctx
*hctx
;
1172 * Initialize hardware queues
1174 queue_for_each_hw_ctx(q
, hctx
, i
) {
1175 unsigned int num_maps
;
1178 node
= hctx
->numa_node
;
1179 if (node
== NUMA_NO_NODE
)
1180 node
= hctx
->numa_node
= reg
->numa_node
;
1182 INIT_DELAYED_WORK(&hctx
->delayed_work
, blk_mq_work_fn
);
1183 spin_lock_init(&hctx
->lock
);
1184 INIT_LIST_HEAD(&hctx
->dispatch
);
1186 hctx
->queue_num
= i
;
1187 hctx
->flags
= reg
->flags
;
1188 hctx
->queue_depth
= reg
->queue_depth
;
1189 hctx
->cmd_size
= reg
->cmd_size
;
1191 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1192 blk_mq_hctx_notify
, hctx
);
1193 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1195 if (blk_mq_init_rq_map(hctx
, reg
->reserved_tags
, node
))
1199 * Allocate space for all possible cpus to avoid allocation in
1202 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1207 num_maps
= ALIGN(nr_cpu_ids
, BITS_PER_LONG
) / BITS_PER_LONG
;
1208 hctx
->ctx_map
= kzalloc_node(num_maps
* sizeof(unsigned long),
1213 hctx
->nr_ctx_map
= num_maps
;
1216 if (reg
->ops
->init_hctx
&&
1217 reg
->ops
->init_hctx(hctx
, driver_data
, i
))
1221 if (i
== q
->nr_hw_queues
)
1227 queue_for_each_hw_ctx(q
, hctx
, j
) {
1231 if (reg
->ops
->exit_hctx
)
1232 reg
->ops
->exit_hctx(hctx
, j
);
1234 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1235 blk_mq_free_rq_map(hctx
);
1242 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1243 unsigned int nr_hw_queues
)
1247 for_each_possible_cpu(i
) {
1248 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1249 struct blk_mq_hw_ctx
*hctx
;
1251 memset(__ctx
, 0, sizeof(*__ctx
));
1253 spin_lock_init(&__ctx
->lock
);
1254 INIT_LIST_HEAD(&__ctx
->rq_list
);
1257 /* If the cpu isn't online, the cpu is mapped to first hctx */
1258 hctx
= q
->mq_ops
->map_queue(q
, i
);
1265 * Set local node, IFF we have more than one hw queue. If
1266 * not, we remain on the home node of the device
1268 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1269 hctx
->numa_node
= cpu_to_node(i
);
1273 static void blk_mq_map_swqueue(struct request_queue
*q
)
1276 struct blk_mq_hw_ctx
*hctx
;
1277 struct blk_mq_ctx
*ctx
;
1279 queue_for_each_hw_ctx(q
, hctx
, i
) {
1284 * Map software to hardware queues
1286 queue_for_each_ctx(q
, ctx
, i
) {
1287 /* If the cpu isn't online, the cpu is mapped to first hctx */
1288 hctx
= q
->mq_ops
->map_queue(q
, i
);
1289 ctx
->index_hw
= hctx
->nr_ctx
;
1290 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1294 struct request_queue
*blk_mq_init_queue(struct blk_mq_reg
*reg
,
1297 struct blk_mq_hw_ctx
**hctxs
;
1298 struct blk_mq_ctx
*ctx
;
1299 struct request_queue
*q
;
1302 if (!reg
->nr_hw_queues
||
1303 !reg
->ops
->queue_rq
|| !reg
->ops
->map_queue
||
1304 !reg
->ops
->alloc_hctx
|| !reg
->ops
->free_hctx
)
1305 return ERR_PTR(-EINVAL
);
1307 if (!reg
->queue_depth
)
1308 reg
->queue_depth
= BLK_MQ_MAX_DEPTH
;
1309 else if (reg
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
1310 pr_err("blk-mq: queuedepth too large (%u)\n", reg
->queue_depth
);
1311 reg
->queue_depth
= BLK_MQ_MAX_DEPTH
;
1314 if (reg
->queue_depth
< (reg
->reserved_tags
+ BLK_MQ_TAG_MIN
))
1315 return ERR_PTR(-EINVAL
);
1317 ctx
= alloc_percpu(struct blk_mq_ctx
);
1319 return ERR_PTR(-ENOMEM
);
1321 hctxs
= kmalloc_node(reg
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1327 for (i
= 0; i
< reg
->nr_hw_queues
; i
++) {
1328 hctxs
[i
] = reg
->ops
->alloc_hctx(reg
, i
);
1332 hctxs
[i
]->numa_node
= NUMA_NO_NODE
;
1333 hctxs
[i
]->queue_num
= i
;
1336 q
= blk_alloc_queue_node(GFP_KERNEL
, reg
->numa_node
);
1340 q
->mq_map
= blk_mq_make_queue_map(reg
);
1344 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1345 blk_queue_rq_timeout(q
, 30000);
1347 q
->nr_queues
= nr_cpu_ids
;
1348 q
->nr_hw_queues
= reg
->nr_hw_queues
;
1351 q
->queue_hw_ctx
= hctxs
;
1353 q
->mq_ops
= reg
->ops
;
1354 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1356 q
->sg_reserved_size
= INT_MAX
;
1358 blk_queue_make_request(q
, blk_mq_make_request
);
1359 blk_queue_rq_timed_out(q
, reg
->ops
->timeout
);
1361 blk_queue_rq_timeout(q
, reg
->timeout
);
1363 if (reg
->ops
->complete
)
1364 blk_queue_softirq_done(q
, reg
->ops
->complete
);
1366 blk_mq_init_flush(q
);
1367 blk_mq_init_cpu_queues(q
, reg
->nr_hw_queues
);
1369 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) + reg
->cmd_size
,
1370 cache_line_size()), GFP_KERNEL
);
1374 if (blk_mq_init_hw_queues(q
, reg
, driver_data
))
1377 blk_mq_map_swqueue(q
);
1379 mutex_lock(&all_q_mutex
);
1380 list_add_tail(&q
->all_q_node
, &all_q_list
);
1381 mutex_unlock(&all_q_mutex
);
1390 blk_cleanup_queue(q
);
1392 for (i
= 0; i
< reg
->nr_hw_queues
; i
++) {
1395 reg
->ops
->free_hctx(hctxs
[i
], i
);
1400 return ERR_PTR(-ENOMEM
);
1402 EXPORT_SYMBOL(blk_mq_init_queue
);
1404 void blk_mq_free_queue(struct request_queue
*q
)
1406 struct blk_mq_hw_ctx
*hctx
;
1409 queue_for_each_hw_ctx(q
, hctx
, i
) {
1410 kfree(hctx
->ctx_map
);
1412 blk_mq_free_rq_map(hctx
);
1413 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1414 if (q
->mq_ops
->exit_hctx
)
1415 q
->mq_ops
->exit_hctx(hctx
, i
);
1416 q
->mq_ops
->free_hctx(hctx
, i
);
1419 free_percpu(q
->queue_ctx
);
1420 kfree(q
->queue_hw_ctx
);
1423 q
->queue_ctx
= NULL
;
1424 q
->queue_hw_ctx
= NULL
;
1427 mutex_lock(&all_q_mutex
);
1428 list_del_init(&q
->all_q_node
);
1429 mutex_unlock(&all_q_mutex
);
1432 /* Basically redo blk_mq_init_queue with queue frozen */
1433 static void blk_mq_queue_reinit(struct request_queue
*q
)
1435 blk_mq_freeze_queue(q
);
1437 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1440 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1441 * we should change hctx numa_node according to new topology (this
1442 * involves free and re-allocate memory, worthy doing?)
1445 blk_mq_map_swqueue(q
);
1447 blk_mq_unfreeze_queue(q
);
1450 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1451 unsigned long action
, void *hcpu
)
1453 struct request_queue
*q
;
1456 * Before new mapping is established, hotadded cpu might already start
1457 * handling requests. This doesn't break anything as we map offline
1458 * CPUs to first hardware queue. We will re-init queue below to get
1461 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1462 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1465 mutex_lock(&all_q_mutex
);
1466 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1467 blk_mq_queue_reinit(q
);
1468 mutex_unlock(&all_q_mutex
);
1472 void blk_mq_disable_hotplug(void)
1474 mutex_lock(&all_q_mutex
);
1477 void blk_mq_enable_hotplug(void)
1479 mutex_unlock(&all_q_mutex
);
1482 static int __init
blk_mq_init(void)
1486 /* Must be called after percpu_counter_hotcpu_callback() */
1487 hotcpu_notifier(blk_mq_queue_reinit_notify
, -10);
1491 subsys_initcall(blk_mq_init
);