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>
24 #include <trace/events/block.h>
26 #include <linux/blk-mq.h>
29 #include "blk-mq-tag.h"
31 static DEFINE_MUTEX(all_q_mutex
);
32 static LIST_HEAD(all_q_list
);
34 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
36 static struct blk_mq_ctx
*__blk_mq_get_ctx(struct request_queue
*q
,
39 return per_cpu_ptr(q
->queue_ctx
, cpu
);
43 * This assumes per-cpu software queueing queues. They could be per-node
44 * as well, for instance. For now this is hardcoded as-is. Note that we don't
45 * care about preemption, since we know the ctx's are persistent. This does
46 * mean that we can't rely on ctx always matching the currently running CPU.
48 static struct blk_mq_ctx
*blk_mq_get_ctx(struct request_queue
*q
)
50 return __blk_mq_get_ctx(q
, get_cpu());
53 static void blk_mq_put_ctx(struct blk_mq_ctx
*ctx
)
59 * Check if any of the ctx's have pending work in this hardware queue
61 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
65 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++)
66 if (hctx
->ctx_map
.map
[i
].word
)
72 static inline struct blk_align_bitmap
*get_bm(struct blk_mq_hw_ctx
*hctx
,
73 struct blk_mq_ctx
*ctx
)
75 return &hctx
->ctx_map
.map
[ctx
->index_hw
/ hctx
->ctx_map
.bits_per_word
];
78 #define CTX_TO_BIT(hctx, ctx) \
79 ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
82 * Mark this ctx as having pending work in this hardware queue
84 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
85 struct blk_mq_ctx
*ctx
)
87 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
89 if (!test_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
))
90 set_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
93 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
94 struct blk_mq_ctx
*ctx
)
96 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
98 clear_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
101 static int blk_mq_queue_enter(struct request_queue
*q
)
105 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
107 /* we have problems to freeze the queue if it's initializing */
108 if (!blk_queue_bypass(q
) || !blk_queue_init_done(q
))
111 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
113 spin_lock_irq(q
->queue_lock
);
114 ret
= wait_event_interruptible_lock_irq(q
->mq_freeze_wq
,
115 !blk_queue_bypass(q
) || blk_queue_dying(q
),
117 /* inc usage with lock hold to avoid freeze_queue runs here */
118 if (!ret
&& !blk_queue_dying(q
))
119 __percpu_counter_add(&q
->mq_usage_counter
, 1, 1000000);
120 else if (blk_queue_dying(q
))
122 spin_unlock_irq(q
->queue_lock
);
127 static void blk_mq_queue_exit(struct request_queue
*q
)
129 __percpu_counter_add(&q
->mq_usage_counter
, -1, 1000000);
132 static void __blk_mq_drain_queue(struct request_queue
*q
)
137 spin_lock_irq(q
->queue_lock
);
138 count
= percpu_counter_sum(&q
->mq_usage_counter
);
139 spin_unlock_irq(q
->queue_lock
);
143 blk_mq_run_queues(q
, false);
149 * Guarantee no request is in use, so we can change any data structure of
150 * the queue afterward.
152 static void blk_mq_freeze_queue(struct request_queue
*q
)
156 spin_lock_irq(q
->queue_lock
);
157 drain
= !q
->bypass_depth
++;
158 queue_flag_set(QUEUE_FLAG_BYPASS
, q
);
159 spin_unlock_irq(q
->queue_lock
);
162 __blk_mq_drain_queue(q
);
165 void blk_mq_drain_queue(struct request_queue
*q
)
167 __blk_mq_drain_queue(q
);
170 static void blk_mq_unfreeze_queue(struct request_queue
*q
)
174 spin_lock_irq(q
->queue_lock
);
175 if (!--q
->bypass_depth
) {
176 queue_flag_clear(QUEUE_FLAG_BYPASS
, q
);
179 WARN_ON_ONCE(q
->bypass_depth
< 0);
180 spin_unlock_irq(q
->queue_lock
);
182 wake_up_all(&q
->mq_freeze_wq
);
185 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
187 return blk_mq_has_free_tags(hctx
->tags
);
189 EXPORT_SYMBOL(blk_mq_can_queue
);
191 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
192 struct request
*rq
, unsigned int rw_flags
)
194 if (blk_queue_io_stat(q
))
195 rw_flags
|= REQ_IO_STAT
;
197 INIT_LIST_HEAD(&rq
->queuelist
);
198 /* csd/requeue_work/fifo_time is initialized before use */
201 rq
->cmd_flags
|= rw_flags
;
203 /* do not touch atomic flags, it needs atomic ops against the timer */
206 rq
->__sector
= (sector_t
) -1;
209 INIT_HLIST_NODE(&rq
->hash
);
210 RB_CLEAR_NODE(&rq
->rb_node
);
211 memset(&rq
->flush
, 0, max(sizeof(rq
->flush
), sizeof(rq
->elv
)));
214 rq
->start_time
= jiffies
;
215 #ifdef CONFIG_BLK_CGROUP
217 set_start_time_ns(rq
);
218 rq
->io_start_time_ns
= 0;
220 rq
->nr_phys_segments
= 0;
221 #if defined(CONFIG_BLK_DEV_INTEGRITY)
222 rq
->nr_integrity_segments
= 0;
226 /* tag was already set */
228 memset(rq
->__cmd
, 0, sizeof(rq
->__cmd
));
230 rq
->cmd_len
= BLK_MAX_CDB
;
238 INIT_LIST_HEAD(&rq
->timeout_list
);
242 rq
->end_io_data
= NULL
;
245 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
248 static struct request
*
249 __blk_mq_alloc_request(struct request_queue
*q
, struct blk_mq_hw_ctx
*hctx
,
250 struct blk_mq_ctx
*ctx
, int rw
, gfp_t gfp
, bool reserved
)
255 tag
= blk_mq_get_tag(hctx
, &ctx
->last_tag
, gfp
, reserved
);
256 if (tag
!= BLK_MQ_TAG_FAIL
) {
257 rq
= hctx
->tags
->rqs
[tag
];
260 if (blk_mq_tag_busy(hctx
)) {
261 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
262 atomic_inc(&hctx
->nr_active
);
266 blk_mq_rq_ctx_init(q
, ctx
, rq
, rw
);
273 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
276 struct blk_mq_ctx
*ctx
;
277 struct blk_mq_hw_ctx
*hctx
;
280 if (blk_mq_queue_enter(q
))
283 ctx
= blk_mq_get_ctx(q
);
284 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
286 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
, gfp
& ~__GFP_WAIT
,
288 if (!rq
&& (gfp
& __GFP_WAIT
)) {
289 __blk_mq_run_hw_queue(hctx
);
292 ctx
= blk_mq_get_ctx(q
);
293 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
294 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
, gfp
, reserved
);
299 EXPORT_SYMBOL(blk_mq_alloc_request
);
301 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
302 struct blk_mq_ctx
*ctx
, struct request
*rq
)
304 const int tag
= rq
->tag
;
305 struct request_queue
*q
= rq
->q
;
307 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
308 atomic_dec(&hctx
->nr_active
);
310 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
311 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
312 blk_mq_queue_exit(q
);
315 void blk_mq_free_request(struct request
*rq
)
317 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
318 struct blk_mq_hw_ctx
*hctx
;
319 struct request_queue
*q
= rq
->q
;
321 ctx
->rq_completed
[rq_is_sync(rq
)]++;
323 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
324 __blk_mq_free_request(hctx
, ctx
, rq
);
328 * Clone all relevant state from a request that has been put on hold in
329 * the flush state machine into the preallocated flush request that hangs
330 * off the request queue.
332 * For a driver the flush request should be invisible, that's why we are
333 * impersonating the original request here.
335 void blk_mq_clone_flush_request(struct request
*flush_rq
,
336 struct request
*orig_rq
)
338 struct blk_mq_hw_ctx
*hctx
=
339 orig_rq
->q
->mq_ops
->map_queue(orig_rq
->q
, orig_rq
->mq_ctx
->cpu
);
341 flush_rq
->mq_ctx
= orig_rq
->mq_ctx
;
342 flush_rq
->tag
= orig_rq
->tag
;
343 memcpy(blk_mq_rq_to_pdu(flush_rq
), blk_mq_rq_to_pdu(orig_rq
),
347 inline void __blk_mq_end_io(struct request
*rq
, int error
)
349 blk_account_io_done(rq
);
352 rq
->end_io(rq
, error
);
354 if (unlikely(blk_bidi_rq(rq
)))
355 blk_mq_free_request(rq
->next_rq
);
356 blk_mq_free_request(rq
);
359 EXPORT_SYMBOL(__blk_mq_end_io
);
361 void blk_mq_end_io(struct request
*rq
, int error
)
363 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
365 __blk_mq_end_io(rq
, error
);
367 EXPORT_SYMBOL(blk_mq_end_io
);
369 static void __blk_mq_complete_request_remote(void *data
)
371 struct request
*rq
= data
;
373 rq
->q
->softirq_done_fn(rq
);
376 void __blk_mq_complete_request(struct request
*rq
)
378 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
382 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
383 rq
->q
->softirq_done_fn(rq
);
388 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
389 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
391 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
392 rq
->csd
.func
= __blk_mq_complete_request_remote
;
395 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
397 rq
->q
->softirq_done_fn(rq
);
403 * blk_mq_complete_request - end I/O on a request
404 * @rq: the request being processed
407 * Ends all I/O on a request. It does not handle partial completions.
408 * The actual completion happens out-of-order, through a IPI handler.
410 void blk_mq_complete_request(struct request
*rq
)
412 struct request_queue
*q
= rq
->q
;
414 if (unlikely(blk_should_fake_timeout(q
)))
416 if (!blk_mark_rq_complete(rq
)) {
417 if (q
->softirq_done_fn
)
418 __blk_mq_complete_request(rq
);
420 blk_mq_end_io(rq
, rq
->errors
);
423 EXPORT_SYMBOL(blk_mq_complete_request
);
425 static void blk_mq_start_request(struct request
*rq
, bool last
)
427 struct request_queue
*q
= rq
->q
;
429 trace_block_rq_issue(q
, rq
);
431 rq
->resid_len
= blk_rq_bytes(rq
);
432 if (unlikely(blk_bidi_rq(rq
)))
433 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
436 * Just mark start time and set the started bit. Due to memory
437 * ordering, we know we'll see the correct deadline as long as
438 * REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
439 * unless one has been set in the request.
442 rq
->deadline
= jiffies
+ q
->rq_timeout
;
444 rq
->deadline
= jiffies
+ rq
->timeout
;
447 * Mark us as started and clear complete. Complete might have been
448 * set if requeue raced with timeout, which then marked it as
449 * complete. So be sure to clear complete again when we start
450 * the request, otherwise we'll ignore the completion event.
452 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
453 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
455 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
457 * Make sure space for the drain appears. We know we can do
458 * this because max_hw_segments has been adjusted to be one
459 * fewer than the device can handle.
461 rq
->nr_phys_segments
++;
465 * Flag the last request in the series so that drivers know when IO
466 * should be kicked off, if they don't do it on a per-request basis.
468 * Note: the flag isn't the only condition drivers should do kick off.
469 * If drive is busy, the last request might not have the bit set.
472 rq
->cmd_flags
|= REQ_END
;
475 static void __blk_mq_requeue_request(struct request
*rq
)
477 struct request_queue
*q
= rq
->q
;
479 trace_block_rq_requeue(q
, rq
);
480 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
482 rq
->cmd_flags
&= ~REQ_END
;
484 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
485 rq
->nr_phys_segments
--;
488 void blk_mq_requeue_request(struct request
*rq
)
490 __blk_mq_requeue_request(rq
);
491 blk_clear_rq_complete(rq
);
493 BUG_ON(blk_queued_rq(rq
));
494 blk_mq_add_to_requeue_list(rq
, true);
496 EXPORT_SYMBOL(blk_mq_requeue_request
);
498 static void blk_mq_requeue_work(struct work_struct
*work
)
500 struct request_queue
*q
=
501 container_of(work
, struct request_queue
, requeue_work
);
503 struct request
*rq
, *next
;
506 spin_lock_irqsave(&q
->requeue_lock
, flags
);
507 list_splice_init(&q
->requeue_list
, &rq_list
);
508 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
510 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
511 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
514 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
515 list_del_init(&rq
->queuelist
);
516 blk_mq_insert_request(rq
, true, false, false);
519 while (!list_empty(&rq_list
)) {
520 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
521 list_del_init(&rq
->queuelist
);
522 blk_mq_insert_request(rq
, false, false, false);
525 blk_mq_run_queues(q
, false);
528 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
530 struct request_queue
*q
= rq
->q
;
534 * We abuse this flag that is otherwise used by the I/O scheduler to
535 * request head insertation from the workqueue.
537 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
539 spin_lock_irqsave(&q
->requeue_lock
, flags
);
541 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
542 list_add(&rq
->queuelist
, &q
->requeue_list
);
544 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
546 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
548 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
550 void blk_mq_kick_requeue_list(struct request_queue
*q
)
552 kblockd_schedule_work(&q
->requeue_work
);
554 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
556 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
558 return tags
->rqs
[tag
];
560 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
562 struct blk_mq_timeout_data
{
563 struct blk_mq_hw_ctx
*hctx
;
565 unsigned int *next_set
;
568 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
570 struct blk_mq_timeout_data
*data
= __data
;
571 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
574 /* It may not be in flight yet (this is where
575 * the REQ_ATOMIC_STARTED flag comes in). The requests are
576 * statically allocated, so we know it's always safe to access the
577 * memory associated with a bit offset into ->rqs[].
583 tag
= find_next_zero_bit(free_tags
, hctx
->tags
->nr_tags
, tag
);
584 if (tag
>= hctx
->tags
->nr_tags
)
587 rq
= blk_mq_tag_to_rq(hctx
->tags
, tag
++);
588 if (rq
->q
!= hctx
->queue
)
590 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
593 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
597 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
599 unsigned int *next_set
)
601 struct blk_mq_timeout_data data
= {
604 .next_set
= next_set
,
608 * Ask the tagging code to iterate busy requests, so we can
609 * check them for timeout.
611 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
614 static enum blk_eh_timer_return
blk_mq_rq_timed_out(struct request
*rq
)
616 struct request_queue
*q
= rq
->q
;
619 * We know that complete is set at this point. If STARTED isn't set
620 * anymore, then the request isn't active and the "timeout" should
621 * just be ignored. This can happen due to the bitflag ordering.
622 * Timeout first checks if STARTED is set, and if it is, assumes
623 * the request is active. But if we race with completion, then
624 * we both flags will get cleared. So check here again, and ignore
625 * a timeout event with a request that isn't active.
627 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
628 return BLK_EH_NOT_HANDLED
;
630 if (!q
->mq_ops
->timeout
)
631 return BLK_EH_RESET_TIMER
;
633 return q
->mq_ops
->timeout(rq
);
636 static void blk_mq_rq_timer(unsigned long data
)
638 struct request_queue
*q
= (struct request_queue
*) data
;
639 struct blk_mq_hw_ctx
*hctx
;
640 unsigned long next
= 0;
643 queue_for_each_hw_ctx(q
, hctx
, i
) {
645 * If not software queues are currently mapped to this
646 * hardware queue, there's nothing to check
648 if (!hctx
->nr_ctx
|| !hctx
->tags
)
651 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
655 next
= blk_rq_timeout(round_jiffies_up(next
));
656 mod_timer(&q
->timeout
, next
);
658 queue_for_each_hw_ctx(q
, hctx
, i
)
659 blk_mq_tag_idle(hctx
);
664 * Reverse check our software queue for entries that we could potentially
665 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
666 * too much time checking for merges.
668 static bool blk_mq_attempt_merge(struct request_queue
*q
,
669 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
674 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
680 if (!blk_rq_merge_ok(rq
, bio
))
683 el_ret
= blk_try_merge(rq
, bio
);
684 if (el_ret
== ELEVATOR_BACK_MERGE
) {
685 if (bio_attempt_back_merge(q
, rq
, bio
)) {
690 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
691 if (bio_attempt_front_merge(q
, rq
, bio
)) {
703 * Process software queues that have been marked busy, splicing them
704 * to the for-dispatch
706 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
708 struct blk_mq_ctx
*ctx
;
711 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
712 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
713 unsigned int off
, bit
;
719 off
= i
* hctx
->ctx_map
.bits_per_word
;
721 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
722 if (bit
>= bm
->depth
)
725 ctx
= hctx
->ctxs
[bit
+ off
];
726 clear_bit(bit
, &bm
->word
);
727 spin_lock(&ctx
->lock
);
728 list_splice_tail_init(&ctx
->rq_list
, list
);
729 spin_unlock(&ctx
->lock
);
737 * Run this hardware queue, pulling any software queues mapped to it in.
738 * Note that this function currently has various problems around ordering
739 * of IO. In particular, we'd like FIFO behaviour on handling existing
740 * items on the hctx->dispatch list. Ignore that for now.
742 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
744 struct request_queue
*q
= hctx
->queue
;
749 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
751 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
757 * Touch any software queue that has pending entries.
759 flush_busy_ctxs(hctx
, &rq_list
);
762 * If we have previous entries on our dispatch list, grab them
763 * and stuff them at the front for more fair dispatch.
765 if (!list_empty_careful(&hctx
->dispatch
)) {
766 spin_lock(&hctx
->lock
);
767 if (!list_empty(&hctx
->dispatch
))
768 list_splice_init(&hctx
->dispatch
, &rq_list
);
769 spin_unlock(&hctx
->lock
);
773 * Now process all the entries, sending them to the driver.
776 while (!list_empty(&rq_list
)) {
779 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
780 list_del_init(&rq
->queuelist
);
782 blk_mq_start_request(rq
, list_empty(&rq_list
));
784 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
786 case BLK_MQ_RQ_QUEUE_OK
:
789 case BLK_MQ_RQ_QUEUE_BUSY
:
790 list_add(&rq
->queuelist
, &rq_list
);
791 __blk_mq_requeue_request(rq
);
794 pr_err("blk-mq: bad return on queue: %d\n", ret
);
795 case BLK_MQ_RQ_QUEUE_ERROR
:
797 blk_mq_end_io(rq
, rq
->errors
);
801 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
806 hctx
->dispatched
[0]++;
807 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
808 hctx
->dispatched
[ilog2(queued
) + 1]++;
811 * Any items that need requeuing? Stuff them into hctx->dispatch,
812 * that is where we will continue on next queue run.
814 if (!list_empty(&rq_list
)) {
815 spin_lock(&hctx
->lock
);
816 list_splice(&rq_list
, &hctx
->dispatch
);
817 spin_unlock(&hctx
->lock
);
822 * It'd be great if the workqueue API had a way to pass
823 * in a mask and had some smarts for more clever placement.
824 * For now we just round-robin here, switching for every
825 * BLK_MQ_CPU_WORK_BATCH queued items.
827 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
829 int cpu
= hctx
->next_cpu
;
831 if (--hctx
->next_cpu_batch
<= 0) {
834 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
835 if (next_cpu
>= nr_cpu_ids
)
836 next_cpu
= cpumask_first(hctx
->cpumask
);
838 hctx
->next_cpu
= next_cpu
;
839 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
845 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
847 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
850 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
851 __blk_mq_run_hw_queue(hctx
);
852 else if (hctx
->queue
->nr_hw_queues
== 1)
853 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
857 cpu
= blk_mq_hctx_next_cpu(hctx
);
858 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
862 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
864 struct blk_mq_hw_ctx
*hctx
;
867 queue_for_each_hw_ctx(q
, hctx
, i
) {
868 if ((!blk_mq_hctx_has_pending(hctx
) &&
869 list_empty_careful(&hctx
->dispatch
)) ||
870 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
874 blk_mq_run_hw_queue(hctx
, async
);
878 EXPORT_SYMBOL(blk_mq_run_queues
);
880 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
882 cancel_delayed_work(&hctx
->run_work
);
883 cancel_delayed_work(&hctx
->delay_work
);
884 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
886 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
888 void blk_mq_stop_hw_queues(struct request_queue
*q
)
890 struct blk_mq_hw_ctx
*hctx
;
893 queue_for_each_hw_ctx(q
, hctx
, i
)
894 blk_mq_stop_hw_queue(hctx
);
896 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
898 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
900 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
903 __blk_mq_run_hw_queue(hctx
);
906 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
908 void blk_mq_start_hw_queues(struct request_queue
*q
)
910 struct blk_mq_hw_ctx
*hctx
;
913 queue_for_each_hw_ctx(q
, hctx
, i
)
914 blk_mq_start_hw_queue(hctx
);
916 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
919 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
921 struct blk_mq_hw_ctx
*hctx
;
924 queue_for_each_hw_ctx(q
, hctx
, i
) {
925 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
928 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
930 blk_mq_run_hw_queue(hctx
, async
);
934 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
936 static void blk_mq_run_work_fn(struct work_struct
*work
)
938 struct blk_mq_hw_ctx
*hctx
;
940 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
942 __blk_mq_run_hw_queue(hctx
);
945 static void blk_mq_delay_work_fn(struct work_struct
*work
)
947 struct blk_mq_hw_ctx
*hctx
;
949 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
951 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
952 __blk_mq_run_hw_queue(hctx
);
955 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
957 unsigned long tmo
= msecs_to_jiffies(msecs
);
959 if (hctx
->queue
->nr_hw_queues
== 1)
960 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
964 cpu
= blk_mq_hctx_next_cpu(hctx
);
965 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
968 EXPORT_SYMBOL(blk_mq_delay_queue
);
970 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
971 struct request
*rq
, bool at_head
)
973 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
975 trace_block_rq_insert(hctx
->queue
, rq
);
978 list_add(&rq
->queuelist
, &ctx
->rq_list
);
980 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
982 blk_mq_hctx_mark_pending(hctx
, ctx
);
985 * We do this early, to ensure we are on the right CPU.
990 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
993 struct request_queue
*q
= rq
->q
;
994 struct blk_mq_hw_ctx
*hctx
;
995 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
997 current_ctx
= blk_mq_get_ctx(q
);
998 if (!cpu_online(ctx
->cpu
))
999 rq
->mq_ctx
= ctx
= current_ctx
;
1001 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1003 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
) &&
1004 !(rq
->cmd_flags
& (REQ_FLUSH_SEQ
))) {
1005 blk_insert_flush(rq
);
1007 spin_lock(&ctx
->lock
);
1008 __blk_mq_insert_request(hctx
, rq
, at_head
);
1009 spin_unlock(&ctx
->lock
);
1013 blk_mq_run_hw_queue(hctx
, async
);
1015 blk_mq_put_ctx(current_ctx
);
1018 static void blk_mq_insert_requests(struct request_queue
*q
,
1019 struct blk_mq_ctx
*ctx
,
1020 struct list_head
*list
,
1025 struct blk_mq_hw_ctx
*hctx
;
1026 struct blk_mq_ctx
*current_ctx
;
1028 trace_block_unplug(q
, depth
, !from_schedule
);
1030 current_ctx
= blk_mq_get_ctx(q
);
1032 if (!cpu_online(ctx
->cpu
))
1034 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1037 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1040 spin_lock(&ctx
->lock
);
1041 while (!list_empty(list
)) {
1044 rq
= list_first_entry(list
, struct request
, queuelist
);
1045 list_del_init(&rq
->queuelist
);
1047 __blk_mq_insert_request(hctx
, rq
, false);
1049 spin_unlock(&ctx
->lock
);
1051 blk_mq_run_hw_queue(hctx
, from_schedule
);
1052 blk_mq_put_ctx(current_ctx
);
1055 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1057 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1058 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1060 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1061 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1062 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1065 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1067 struct blk_mq_ctx
*this_ctx
;
1068 struct request_queue
*this_q
;
1071 LIST_HEAD(ctx_list
);
1074 list_splice_init(&plug
->mq_list
, &list
);
1076 list_sort(NULL
, &list
, plug_ctx_cmp
);
1082 while (!list_empty(&list
)) {
1083 rq
= list_entry_rq(list
.next
);
1084 list_del_init(&rq
->queuelist
);
1086 if (rq
->mq_ctx
!= this_ctx
) {
1088 blk_mq_insert_requests(this_q
, this_ctx
,
1093 this_ctx
= rq
->mq_ctx
;
1099 list_add_tail(&rq
->queuelist
, &ctx_list
);
1103 * If 'this_ctx' is set, we know we have entries to complete
1104 * on 'ctx_list'. Do those.
1107 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1112 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1114 init_request_from_bio(rq
, bio
);
1115 blk_account_io_start(rq
, 1);
1118 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1119 struct blk_mq_ctx
*ctx
,
1120 struct request
*rq
, struct bio
*bio
)
1122 struct request_queue
*q
= hctx
->queue
;
1124 if (!(hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
)) {
1125 blk_mq_bio_to_request(rq
, bio
);
1126 spin_lock(&ctx
->lock
);
1128 __blk_mq_insert_request(hctx
, rq
, false);
1129 spin_unlock(&ctx
->lock
);
1132 spin_lock(&ctx
->lock
);
1133 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1134 blk_mq_bio_to_request(rq
, bio
);
1138 spin_unlock(&ctx
->lock
);
1139 __blk_mq_free_request(hctx
, ctx
, rq
);
1144 struct blk_map_ctx
{
1145 struct blk_mq_hw_ctx
*hctx
;
1146 struct blk_mq_ctx
*ctx
;
1149 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1151 struct blk_map_ctx
*data
)
1153 struct blk_mq_hw_ctx
*hctx
;
1154 struct blk_mq_ctx
*ctx
;
1156 int rw
= bio_data_dir(bio
);
1158 if (unlikely(blk_mq_queue_enter(q
))) {
1159 bio_endio(bio
, -EIO
);
1163 ctx
= blk_mq_get_ctx(q
);
1164 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1166 if (rw_is_sync(bio
->bi_rw
))
1169 trace_block_getrq(q
, bio
, rw
);
1170 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
, GFP_ATOMIC
, false);
1171 if (unlikely(!rq
)) {
1172 __blk_mq_run_hw_queue(hctx
);
1173 blk_mq_put_ctx(ctx
);
1174 trace_block_sleeprq(q
, bio
, rw
);
1176 ctx
= blk_mq_get_ctx(q
);
1177 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1178 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
,
1179 __GFP_WAIT
|GFP_ATOMIC
, false);
1189 * Multiple hardware queue variant. This will not use per-process plugs,
1190 * but will attempt to bypass the hctx queueing if we can go straight to
1191 * hardware for SYNC IO.
1193 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1195 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1196 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1197 struct blk_map_ctx data
;
1200 blk_queue_bounce(q
, &bio
);
1202 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1203 bio_endio(bio
, -EIO
);
1207 rq
= blk_mq_map_request(q
, bio
, &data
);
1211 if (unlikely(is_flush_fua
)) {
1212 blk_mq_bio_to_request(rq
, bio
);
1213 blk_insert_flush(rq
);
1220 blk_mq_bio_to_request(rq
, bio
);
1221 blk_mq_start_request(rq
, true);
1224 * For OK queue, we are done. For error, kill it. Any other
1225 * error (busy), just add it to our list as we previously
1228 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
);
1229 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1232 __blk_mq_requeue_request(rq
);
1234 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1236 blk_mq_end_io(rq
, rq
->errors
);
1242 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1244 * For a SYNC request, send it to the hardware immediately. For
1245 * an ASYNC request, just ensure that we run it later on. The
1246 * latter allows for merging opportunities and more efficient
1250 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1253 blk_mq_put_ctx(data
.ctx
);
1257 * Single hardware queue variant. This will attempt to use any per-process
1258 * plug for merging and IO deferral.
1260 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1262 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1263 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1264 unsigned int use_plug
, request_count
= 0;
1265 struct blk_map_ctx data
;
1269 * If we have multiple hardware queues, just go directly to
1270 * one of those for sync IO.
1272 use_plug
= !is_flush_fua
&& !is_sync
;
1274 blk_queue_bounce(q
, &bio
);
1276 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1277 bio_endio(bio
, -EIO
);
1281 if (use_plug
&& !blk_queue_nomerges(q
) &&
1282 blk_attempt_plug_merge(q
, bio
, &request_count
))
1285 rq
= blk_mq_map_request(q
, bio
, &data
);
1287 if (unlikely(is_flush_fua
)) {
1288 blk_mq_bio_to_request(rq
, bio
);
1289 blk_insert_flush(rq
);
1294 * A task plug currently exists. Since this is completely lockless,
1295 * utilize that to temporarily store requests until the task is
1296 * either done or scheduled away.
1299 struct blk_plug
*plug
= current
->plug
;
1302 blk_mq_bio_to_request(rq
, bio
);
1303 if (list_empty(&plug
->mq_list
))
1304 trace_block_plug(q
);
1305 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1306 blk_flush_plug_list(plug
, false);
1307 trace_block_plug(q
);
1309 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1310 blk_mq_put_ctx(data
.ctx
);
1315 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1317 * For a SYNC request, send it to the hardware immediately. For
1318 * an ASYNC request, just ensure that we run it later on. The
1319 * latter allows for merging opportunities and more efficient
1323 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1326 blk_mq_put_ctx(data
.ctx
);
1330 * Default mapping to a software queue, since we use one per CPU.
1332 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1334 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1336 EXPORT_SYMBOL(blk_mq_map_queue
);
1338 struct blk_mq_hw_ctx
*blk_mq_alloc_single_hw_queue(struct blk_mq_tag_set
*set
,
1339 unsigned int hctx_index
,
1342 return kzalloc_node(sizeof(struct blk_mq_hw_ctx
), GFP_KERNEL
, node
);
1344 EXPORT_SYMBOL(blk_mq_alloc_single_hw_queue
);
1346 void blk_mq_free_single_hw_queue(struct blk_mq_hw_ctx
*hctx
,
1347 unsigned int hctx_index
)
1351 EXPORT_SYMBOL(blk_mq_free_single_hw_queue
);
1353 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1354 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1358 if (tags
->rqs
&& set
->ops
->exit_request
) {
1361 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1364 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1369 while (!list_empty(&tags
->page_list
)) {
1370 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1371 list_del_init(&page
->lru
);
1372 __free_pages(page
, page
->private);
1377 blk_mq_free_tags(tags
);
1380 static size_t order_to_size(unsigned int order
)
1382 return (size_t)PAGE_SIZE
<< order
;
1385 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1386 unsigned int hctx_idx
)
1388 struct blk_mq_tags
*tags
;
1389 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1390 size_t rq_size
, left
;
1392 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1397 INIT_LIST_HEAD(&tags
->page_list
);
1399 tags
->rqs
= kmalloc_node(set
->queue_depth
* sizeof(struct request
*),
1400 GFP_KERNEL
, set
->numa_node
);
1402 blk_mq_free_tags(tags
);
1407 * rq_size is the size of the request plus driver payload, rounded
1408 * to the cacheline size
1410 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1412 left
= rq_size
* set
->queue_depth
;
1414 for (i
= 0; i
< set
->queue_depth
; ) {
1415 int this_order
= max_order
;
1420 while (left
< order_to_size(this_order
- 1) && this_order
)
1424 page
= alloc_pages_node(set
->numa_node
, GFP_KERNEL
,
1430 if (order_to_size(this_order
) < rq_size
)
1437 page
->private = this_order
;
1438 list_add_tail(&page
->lru
, &tags
->page_list
);
1440 p
= page_address(page
);
1441 entries_per_page
= order_to_size(this_order
) / rq_size
;
1442 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1443 left
-= to_do
* rq_size
;
1444 for (j
= 0; j
< to_do
; j
++) {
1446 if (set
->ops
->init_request
) {
1447 if (set
->ops
->init_request(set
->driver_data
,
1448 tags
->rqs
[i
], hctx_idx
, i
,
1461 pr_warn("%s: failed to allocate requests\n", __func__
);
1462 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1466 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1471 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1473 unsigned int bpw
= 8, total
, num_maps
, i
;
1475 bitmap
->bits_per_word
= bpw
;
1477 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1478 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1483 bitmap
->map_size
= num_maps
;
1486 for (i
= 0; i
< num_maps
; i
++) {
1487 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1488 total
-= bitmap
->map
[i
].depth
;
1494 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1496 struct request_queue
*q
= hctx
->queue
;
1497 struct blk_mq_ctx
*ctx
;
1501 * Move ctx entries to new CPU, if this one is going away.
1503 ctx
= __blk_mq_get_ctx(q
, cpu
);
1505 spin_lock(&ctx
->lock
);
1506 if (!list_empty(&ctx
->rq_list
)) {
1507 list_splice_init(&ctx
->rq_list
, &tmp
);
1508 blk_mq_hctx_clear_pending(hctx
, ctx
);
1510 spin_unlock(&ctx
->lock
);
1512 if (list_empty(&tmp
))
1515 ctx
= blk_mq_get_ctx(q
);
1516 spin_lock(&ctx
->lock
);
1518 while (!list_empty(&tmp
)) {
1521 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1523 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1526 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1527 blk_mq_hctx_mark_pending(hctx
, ctx
);
1529 spin_unlock(&ctx
->lock
);
1531 blk_mq_run_hw_queue(hctx
, true);
1532 blk_mq_put_ctx(ctx
);
1536 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1538 struct request_queue
*q
= hctx
->queue
;
1539 struct blk_mq_tag_set
*set
= q
->tag_set
;
1541 if (set
->tags
[hctx
->queue_num
])
1544 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1545 if (!set
->tags
[hctx
->queue_num
])
1548 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1552 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1555 struct blk_mq_hw_ctx
*hctx
= data
;
1557 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1558 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1559 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1560 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1565 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1566 struct blk_mq_tag_set
*set
, int nr_queue
)
1568 struct blk_mq_hw_ctx
*hctx
;
1571 queue_for_each_hw_ctx(q
, hctx
, i
) {
1575 if (set
->ops
->exit_hctx
)
1576 set
->ops
->exit_hctx(hctx
, i
);
1578 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1580 blk_mq_free_bitmap(&hctx
->ctx_map
);
1585 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1586 struct blk_mq_tag_set
*set
)
1588 struct blk_mq_hw_ctx
*hctx
;
1591 queue_for_each_hw_ctx(q
, hctx
, i
) {
1592 free_cpumask_var(hctx
->cpumask
);
1593 set
->ops
->free_hctx(hctx
, i
);
1597 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1598 struct blk_mq_tag_set
*set
)
1600 struct blk_mq_hw_ctx
*hctx
;
1604 * Initialize hardware queues
1606 queue_for_each_hw_ctx(q
, hctx
, i
) {
1609 node
= hctx
->numa_node
;
1610 if (node
== NUMA_NO_NODE
)
1611 node
= hctx
->numa_node
= set
->numa_node
;
1613 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1614 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1615 spin_lock_init(&hctx
->lock
);
1616 INIT_LIST_HEAD(&hctx
->dispatch
);
1618 hctx
->queue_num
= i
;
1619 hctx
->flags
= set
->flags
;
1620 hctx
->cmd_size
= set
->cmd_size
;
1622 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1623 blk_mq_hctx_notify
, hctx
);
1624 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1626 hctx
->tags
= set
->tags
[i
];
1629 * Allocate space for all possible cpus to avoid allocation in
1632 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1637 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1642 if (set
->ops
->init_hctx
&&
1643 set
->ops
->init_hctx(hctx
, set
->driver_data
, i
))
1647 if (i
== q
->nr_hw_queues
)
1653 blk_mq_exit_hw_queues(q
, set
, i
);
1658 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1659 unsigned int nr_hw_queues
)
1663 for_each_possible_cpu(i
) {
1664 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1665 struct blk_mq_hw_ctx
*hctx
;
1667 memset(__ctx
, 0, sizeof(*__ctx
));
1669 spin_lock_init(&__ctx
->lock
);
1670 INIT_LIST_HEAD(&__ctx
->rq_list
);
1673 /* If the cpu isn't online, the cpu is mapped to first hctx */
1677 hctx
= q
->mq_ops
->map_queue(q
, i
);
1678 cpumask_set_cpu(i
, hctx
->cpumask
);
1682 * Set local node, IFF we have more than one hw queue. If
1683 * not, we remain on the home node of the device
1685 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1686 hctx
->numa_node
= cpu_to_node(i
);
1690 static void blk_mq_map_swqueue(struct request_queue
*q
)
1693 struct blk_mq_hw_ctx
*hctx
;
1694 struct blk_mq_ctx
*ctx
;
1696 queue_for_each_hw_ctx(q
, hctx
, i
) {
1697 cpumask_clear(hctx
->cpumask
);
1702 * Map software to hardware queues
1704 queue_for_each_ctx(q
, ctx
, i
) {
1705 /* If the cpu isn't online, the cpu is mapped to first hctx */
1709 hctx
= q
->mq_ops
->map_queue(q
, i
);
1710 cpumask_set_cpu(i
, hctx
->cpumask
);
1711 ctx
->index_hw
= hctx
->nr_ctx
;
1712 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1715 queue_for_each_hw_ctx(q
, hctx
, i
) {
1717 * If not software queues are mapped to this hardware queue,
1718 * disable it and free the request entries
1720 if (!hctx
->nr_ctx
) {
1721 struct blk_mq_tag_set
*set
= q
->tag_set
;
1724 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1725 set
->tags
[i
] = NULL
;
1732 * Initialize batch roundrobin counts
1734 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1735 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1739 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1741 struct blk_mq_hw_ctx
*hctx
;
1742 struct request_queue
*q
;
1746 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1751 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1752 blk_mq_freeze_queue(q
);
1754 queue_for_each_hw_ctx(q
, hctx
, i
) {
1756 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1758 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1760 blk_mq_unfreeze_queue(q
);
1764 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1766 struct blk_mq_tag_set
*set
= q
->tag_set
;
1768 blk_mq_freeze_queue(q
);
1770 mutex_lock(&set
->tag_list_lock
);
1771 list_del_init(&q
->tag_set_list
);
1772 blk_mq_update_tag_set_depth(set
);
1773 mutex_unlock(&set
->tag_list_lock
);
1775 blk_mq_unfreeze_queue(q
);
1778 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1779 struct request_queue
*q
)
1783 mutex_lock(&set
->tag_list_lock
);
1784 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1785 blk_mq_update_tag_set_depth(set
);
1786 mutex_unlock(&set
->tag_list_lock
);
1789 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1791 struct blk_mq_hw_ctx
**hctxs
;
1792 struct blk_mq_ctx
*ctx
;
1793 struct request_queue
*q
;
1797 ctx
= alloc_percpu(struct blk_mq_ctx
);
1799 return ERR_PTR(-ENOMEM
);
1801 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1807 map
= blk_mq_make_queue_map(set
);
1811 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1812 int node
= blk_mq_hw_queue_to_node(map
, i
);
1814 hctxs
[i
] = set
->ops
->alloc_hctx(set
, i
, node
);
1818 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1821 atomic_set(&hctxs
[i
]->nr_active
, 0);
1822 hctxs
[i
]->numa_node
= node
;
1823 hctxs
[i
]->queue_num
= i
;
1826 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1830 if (percpu_counter_init(&q
->mq_usage_counter
, 0))
1833 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1834 blk_queue_rq_timeout(q
, 30000);
1836 q
->nr_queues
= nr_cpu_ids
;
1837 q
->nr_hw_queues
= set
->nr_hw_queues
;
1841 q
->queue_hw_ctx
= hctxs
;
1843 q
->mq_ops
= set
->ops
;
1844 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1846 q
->sg_reserved_size
= INT_MAX
;
1848 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1849 INIT_LIST_HEAD(&q
->requeue_list
);
1850 spin_lock_init(&q
->requeue_lock
);
1852 if (q
->nr_hw_queues
> 1)
1853 blk_queue_make_request(q
, blk_mq_make_request
);
1855 blk_queue_make_request(q
, blk_sq_make_request
);
1857 blk_queue_rq_timed_out(q
, blk_mq_rq_timed_out
);
1859 blk_queue_rq_timeout(q
, set
->timeout
);
1862 * Do this after blk_queue_make_request() overrides it...
1864 q
->nr_requests
= set
->queue_depth
;
1866 if (set
->ops
->complete
)
1867 blk_queue_softirq_done(q
, set
->ops
->complete
);
1869 blk_mq_init_flush(q
);
1870 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1872 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) +
1873 set
->cmd_size
, cache_line_size()),
1878 if (blk_mq_init_hw_queues(q
, set
))
1881 mutex_lock(&all_q_mutex
);
1882 list_add_tail(&q
->all_q_node
, &all_q_list
);
1883 mutex_unlock(&all_q_mutex
);
1885 blk_mq_add_queue_tag_set(set
, q
);
1887 blk_mq_map_swqueue(q
);
1894 blk_cleanup_queue(q
);
1897 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1900 free_cpumask_var(hctxs
[i
]->cpumask
);
1901 set
->ops
->free_hctx(hctxs
[i
], i
);
1907 return ERR_PTR(-ENOMEM
);
1909 EXPORT_SYMBOL(blk_mq_init_queue
);
1911 void blk_mq_free_queue(struct request_queue
*q
)
1913 struct blk_mq_tag_set
*set
= q
->tag_set
;
1915 blk_mq_del_queue_tag_set(q
);
1917 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1918 blk_mq_free_hw_queues(q
, set
);
1920 percpu_counter_destroy(&q
->mq_usage_counter
);
1922 free_percpu(q
->queue_ctx
);
1923 kfree(q
->queue_hw_ctx
);
1926 q
->queue_ctx
= NULL
;
1927 q
->queue_hw_ctx
= NULL
;
1930 mutex_lock(&all_q_mutex
);
1931 list_del_init(&q
->all_q_node
);
1932 mutex_unlock(&all_q_mutex
);
1935 /* Basically redo blk_mq_init_queue with queue frozen */
1936 static void blk_mq_queue_reinit(struct request_queue
*q
)
1938 blk_mq_freeze_queue(q
);
1940 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1943 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1944 * we should change hctx numa_node according to new topology (this
1945 * involves free and re-allocate memory, worthy doing?)
1948 blk_mq_map_swqueue(q
);
1950 blk_mq_unfreeze_queue(q
);
1953 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1954 unsigned long action
, void *hcpu
)
1956 struct request_queue
*q
;
1959 * Before new mappings are established, hotadded cpu might already
1960 * start handling requests. This doesn't break anything as we map
1961 * offline CPUs to first hardware queue. We will re-init the queue
1962 * below to get optimal settings.
1964 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1965 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1968 mutex_lock(&all_q_mutex
);
1969 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1970 blk_mq_queue_reinit(q
);
1971 mutex_unlock(&all_q_mutex
);
1975 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
1979 if (!set
->nr_hw_queues
)
1981 if (!set
->queue_depth
|| set
->queue_depth
> BLK_MQ_MAX_DEPTH
)
1983 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
1986 if (!set
->nr_hw_queues
||
1987 !set
->ops
->queue_rq
|| !set
->ops
->map_queue
||
1988 !set
->ops
->alloc_hctx
|| !set
->ops
->free_hctx
)
1992 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
1993 sizeof(struct blk_mq_tags
*),
1994 GFP_KERNEL
, set
->numa_node
);
1998 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1999 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
2004 mutex_init(&set
->tag_list_lock
);
2005 INIT_LIST_HEAD(&set
->tag_list
);
2011 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2015 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2017 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2021 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2023 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2028 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2030 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2032 struct blk_mq_tag_set
*set
= q
->tag_set
;
2033 struct blk_mq_hw_ctx
*hctx
;
2036 if (!set
|| nr
> set
->queue_depth
)
2040 queue_for_each_hw_ctx(q
, hctx
, i
) {
2041 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2047 q
->nr_requests
= nr
;
2052 void blk_mq_disable_hotplug(void)
2054 mutex_lock(&all_q_mutex
);
2057 void blk_mq_enable_hotplug(void)
2059 mutex_unlock(&all_q_mutex
);
2062 static int __init
blk_mq_init(void)
2066 /* Must be called after percpu_counter_hotcpu_callback() */
2067 hotcpu_notifier(blk_mq_queue_reinit_notify
, -10);
2071 subsys_initcall(blk_mq_init
);