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
;
202 /* do not touch atomic flags, it needs atomic ops against the timer */
204 INIT_HLIST_NODE(&rq
->hash
);
205 RB_CLEAR_NODE(&rq
->rb_node
);
208 #ifdef CONFIG_BLK_CGROUP
210 set_start_time_ns(rq
);
211 rq
->io_start_time_ns
= 0;
213 rq
->nr_phys_segments
= 0;
214 #if defined(CONFIG_BLK_DEV_INTEGRITY)
215 rq
->nr_integrity_segments
= 0;
218 /* tag was already set */
226 INIT_LIST_HEAD(&rq
->timeout_list
);
228 rq
->end_io_data
= NULL
;
231 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
234 static struct request
*
235 __blk_mq_alloc_request(struct request_queue
*q
, struct blk_mq_hw_ctx
*hctx
,
236 struct blk_mq_ctx
*ctx
, int rw
, gfp_t gfp
, bool reserved
)
241 tag
= blk_mq_get_tag(hctx
, &ctx
->last_tag
, gfp
, reserved
);
242 if (tag
!= BLK_MQ_TAG_FAIL
) {
243 rq
= hctx
->tags
->rqs
[tag
];
246 if (blk_mq_tag_busy(hctx
)) {
247 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
248 atomic_inc(&hctx
->nr_active
);
252 blk_mq_rq_ctx_init(q
, ctx
, rq
, rw
);
259 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
262 struct blk_mq_ctx
*ctx
;
263 struct blk_mq_hw_ctx
*hctx
;
266 if (blk_mq_queue_enter(q
))
269 ctx
= blk_mq_get_ctx(q
);
270 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
272 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
, gfp
& ~__GFP_WAIT
,
274 if (!rq
&& (gfp
& __GFP_WAIT
)) {
275 __blk_mq_run_hw_queue(hctx
);
278 ctx
= blk_mq_get_ctx(q
);
279 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
280 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
, gfp
, reserved
);
285 EXPORT_SYMBOL(blk_mq_alloc_request
);
287 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
288 struct blk_mq_ctx
*ctx
, struct request
*rq
)
290 const int tag
= rq
->tag
;
291 struct request_queue
*q
= rq
->q
;
293 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
294 atomic_dec(&hctx
->nr_active
);
296 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
297 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
298 blk_mq_queue_exit(q
);
301 void blk_mq_free_request(struct request
*rq
)
303 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
304 struct blk_mq_hw_ctx
*hctx
;
305 struct request_queue
*q
= rq
->q
;
307 ctx
->rq_completed
[rq_is_sync(rq
)]++;
309 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
310 __blk_mq_free_request(hctx
, ctx
, rq
);
314 * Clone all relevant state from a request that has been put on hold in
315 * the flush state machine into the preallocated flush request that hangs
316 * off the request queue.
318 * For a driver the flush request should be invisible, that's why we are
319 * impersonating the original request here.
321 void blk_mq_clone_flush_request(struct request
*flush_rq
,
322 struct request
*orig_rq
)
324 struct blk_mq_hw_ctx
*hctx
=
325 orig_rq
->q
->mq_ops
->map_queue(orig_rq
->q
, orig_rq
->mq_ctx
->cpu
);
327 flush_rq
->mq_ctx
= orig_rq
->mq_ctx
;
328 flush_rq
->tag
= orig_rq
->tag
;
329 memcpy(blk_mq_rq_to_pdu(flush_rq
), blk_mq_rq_to_pdu(orig_rq
),
333 inline void __blk_mq_end_io(struct request
*rq
, int error
)
335 blk_account_io_done(rq
);
338 rq
->end_io(rq
, error
);
340 if (unlikely(blk_bidi_rq(rq
)))
341 blk_mq_free_request(rq
->next_rq
);
342 blk_mq_free_request(rq
);
345 EXPORT_SYMBOL(__blk_mq_end_io
);
347 void blk_mq_end_io(struct request
*rq
, int error
)
349 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
351 __blk_mq_end_io(rq
, error
);
353 EXPORT_SYMBOL(blk_mq_end_io
);
355 static void __blk_mq_complete_request_remote(void *data
)
357 struct request
*rq
= data
;
359 rq
->q
->softirq_done_fn(rq
);
362 void __blk_mq_complete_request(struct request
*rq
)
364 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
368 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
369 rq
->q
->softirq_done_fn(rq
);
374 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
375 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
377 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
378 rq
->csd
.func
= __blk_mq_complete_request_remote
;
381 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
383 rq
->q
->softirq_done_fn(rq
);
389 * blk_mq_complete_request - end I/O on a request
390 * @rq: the request being processed
393 * Ends all I/O on a request. It does not handle partial completions.
394 * The actual completion happens out-of-order, through a IPI handler.
396 void blk_mq_complete_request(struct request
*rq
)
398 struct request_queue
*q
= rq
->q
;
400 if (unlikely(blk_should_fake_timeout(q
)))
402 if (!blk_mark_rq_complete(rq
)) {
403 if (q
->softirq_done_fn
)
404 __blk_mq_complete_request(rq
);
406 blk_mq_end_io(rq
, rq
->errors
);
409 EXPORT_SYMBOL(blk_mq_complete_request
);
411 static void blk_mq_start_request(struct request
*rq
, bool last
)
413 struct request_queue
*q
= rq
->q
;
415 trace_block_rq_issue(q
, rq
);
417 rq
->resid_len
= blk_rq_bytes(rq
);
418 if (unlikely(blk_bidi_rq(rq
)))
419 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
422 * Just mark start time and set the started bit. Due to memory
423 * ordering, we know we'll see the correct deadline as long as
424 * REQ_ATOMIC_STARTED is seen. Use the default queue timeout,
425 * unless one has been set in the request.
428 rq
->deadline
= jiffies
+ q
->rq_timeout
;
430 rq
->deadline
= jiffies
+ rq
->timeout
;
433 * Mark us as started and clear complete. Complete might have been
434 * set if requeue raced with timeout, which then marked it as
435 * complete. So be sure to clear complete again when we start
436 * the request, otherwise we'll ignore the completion event.
438 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
439 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
440 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
441 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
443 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
445 * Make sure space for the drain appears. We know we can do
446 * this because max_hw_segments has been adjusted to be one
447 * fewer than the device can handle.
449 rq
->nr_phys_segments
++;
453 * Flag the last request in the series so that drivers know when IO
454 * should be kicked off, if they don't do it on a per-request basis.
456 * Note: the flag isn't the only condition drivers should do kick off.
457 * If drive is busy, the last request might not have the bit set.
460 rq
->cmd_flags
|= REQ_END
;
463 static void __blk_mq_requeue_request(struct request
*rq
)
465 struct request_queue
*q
= rq
->q
;
467 trace_block_rq_requeue(q
, rq
);
468 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
470 rq
->cmd_flags
&= ~REQ_END
;
472 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
473 rq
->nr_phys_segments
--;
476 void blk_mq_requeue_request(struct request
*rq
)
478 __blk_mq_requeue_request(rq
);
479 blk_clear_rq_complete(rq
);
481 BUG_ON(blk_queued_rq(rq
));
482 blk_mq_add_to_requeue_list(rq
, true);
484 EXPORT_SYMBOL(blk_mq_requeue_request
);
486 static void blk_mq_requeue_work(struct work_struct
*work
)
488 struct request_queue
*q
=
489 container_of(work
, struct request_queue
, requeue_work
);
491 struct request
*rq
, *next
;
494 spin_lock_irqsave(&q
->requeue_lock
, flags
);
495 list_splice_init(&q
->requeue_list
, &rq_list
);
496 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
498 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
499 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
502 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
503 list_del_init(&rq
->queuelist
);
504 blk_mq_insert_request(rq
, true, false, false);
507 while (!list_empty(&rq_list
)) {
508 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
509 list_del_init(&rq
->queuelist
);
510 blk_mq_insert_request(rq
, false, false, false);
513 blk_mq_run_queues(q
, false);
516 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
518 struct request_queue
*q
= rq
->q
;
522 * We abuse this flag that is otherwise used by the I/O scheduler to
523 * request head insertation from the workqueue.
525 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
527 spin_lock_irqsave(&q
->requeue_lock
, flags
);
529 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
530 list_add(&rq
->queuelist
, &q
->requeue_list
);
532 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
534 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
536 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
538 void blk_mq_kick_requeue_list(struct request_queue
*q
)
540 kblockd_schedule_work(&q
->requeue_work
);
542 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
544 struct request
*blk_mq_tag_to_rq(struct blk_mq_hw_ctx
*hctx
, unsigned int tag
)
546 struct request_queue
*q
= hctx
->queue
;
548 if ((q
->flush_rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
549 q
->flush_rq
->tag
== tag
)
552 return hctx
->tags
->rqs
[tag
];
554 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
556 struct blk_mq_timeout_data
{
557 struct blk_mq_hw_ctx
*hctx
;
559 unsigned int *next_set
;
562 static void blk_mq_timeout_check(void *__data
, unsigned long *free_tags
)
564 struct blk_mq_timeout_data
*data
= __data
;
565 struct blk_mq_hw_ctx
*hctx
= data
->hctx
;
568 /* It may not be in flight yet (this is where
569 * the REQ_ATOMIC_STARTED flag comes in). The requests are
570 * statically allocated, so we know it's always safe to access the
571 * memory associated with a bit offset into ->rqs[].
577 tag
= find_next_zero_bit(free_tags
, hctx
->tags
->nr_tags
, tag
);
578 if (tag
>= hctx
->tags
->nr_tags
)
581 rq
= blk_mq_tag_to_rq(hctx
, tag
++);
582 if (rq
->q
!= hctx
->queue
)
584 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
587 blk_rq_check_expired(rq
, data
->next
, data
->next_set
);
591 static void blk_mq_hw_ctx_check_timeout(struct blk_mq_hw_ctx
*hctx
,
593 unsigned int *next_set
)
595 struct blk_mq_timeout_data data
= {
598 .next_set
= next_set
,
602 * Ask the tagging code to iterate busy requests, so we can
603 * check them for timeout.
605 blk_mq_tag_busy_iter(hctx
->tags
, blk_mq_timeout_check
, &data
);
608 static enum blk_eh_timer_return
blk_mq_rq_timed_out(struct request
*rq
)
610 struct request_queue
*q
= rq
->q
;
613 * We know that complete is set at this point. If STARTED isn't set
614 * anymore, then the request isn't active and the "timeout" should
615 * just be ignored. This can happen due to the bitflag ordering.
616 * Timeout first checks if STARTED is set, and if it is, assumes
617 * the request is active. But if we race with completion, then
618 * we both flags will get cleared. So check here again, and ignore
619 * a timeout event with a request that isn't active.
621 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
622 return BLK_EH_NOT_HANDLED
;
624 if (!q
->mq_ops
->timeout
)
625 return BLK_EH_RESET_TIMER
;
627 return q
->mq_ops
->timeout(rq
);
630 static void blk_mq_rq_timer(unsigned long data
)
632 struct request_queue
*q
= (struct request_queue
*) data
;
633 struct blk_mq_hw_ctx
*hctx
;
634 unsigned long next
= 0;
637 queue_for_each_hw_ctx(q
, hctx
, i
) {
639 * If not software queues are currently mapped to this
640 * hardware queue, there's nothing to check
642 if (!hctx
->nr_ctx
|| !hctx
->tags
)
645 blk_mq_hw_ctx_check_timeout(hctx
, &next
, &next_set
);
649 next
= blk_rq_timeout(round_jiffies_up(next
));
650 mod_timer(&q
->timeout
, next
);
652 queue_for_each_hw_ctx(q
, hctx
, i
)
653 blk_mq_tag_idle(hctx
);
658 * Reverse check our software queue for entries that we could potentially
659 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
660 * too much time checking for merges.
662 static bool blk_mq_attempt_merge(struct request_queue
*q
,
663 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
668 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
674 if (!blk_rq_merge_ok(rq
, bio
))
677 el_ret
= blk_try_merge(rq
, bio
);
678 if (el_ret
== ELEVATOR_BACK_MERGE
) {
679 if (bio_attempt_back_merge(q
, rq
, bio
)) {
684 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
685 if (bio_attempt_front_merge(q
, rq
, bio
)) {
697 * Process software queues that have been marked busy, splicing them
698 * to the for-dispatch
700 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
702 struct blk_mq_ctx
*ctx
;
705 for (i
= 0; i
< hctx
->ctx_map
.map_size
; i
++) {
706 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
707 unsigned int off
, bit
;
713 off
= i
* hctx
->ctx_map
.bits_per_word
;
715 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
716 if (bit
>= bm
->depth
)
719 ctx
= hctx
->ctxs
[bit
+ off
];
720 clear_bit(bit
, &bm
->word
);
721 spin_lock(&ctx
->lock
);
722 list_splice_tail_init(&ctx
->rq_list
, list
);
723 spin_unlock(&ctx
->lock
);
731 * Run this hardware queue, pulling any software queues mapped to it in.
732 * Note that this function currently has various problems around ordering
733 * of IO. In particular, we'd like FIFO behaviour on handling existing
734 * items on the hctx->dispatch list. Ignore that for now.
736 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
738 struct request_queue
*q
= hctx
->queue
;
743 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
745 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
751 * Touch any software queue that has pending entries.
753 flush_busy_ctxs(hctx
, &rq_list
);
756 * If we have previous entries on our dispatch list, grab them
757 * and stuff them at the front for more fair dispatch.
759 if (!list_empty_careful(&hctx
->dispatch
)) {
760 spin_lock(&hctx
->lock
);
761 if (!list_empty(&hctx
->dispatch
))
762 list_splice_init(&hctx
->dispatch
, &rq_list
);
763 spin_unlock(&hctx
->lock
);
767 * Now process all the entries, sending them to the driver.
770 while (!list_empty(&rq_list
)) {
773 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
774 list_del_init(&rq
->queuelist
);
776 blk_mq_start_request(rq
, list_empty(&rq_list
));
778 ret
= q
->mq_ops
->queue_rq(hctx
, rq
);
780 case BLK_MQ_RQ_QUEUE_OK
:
783 case BLK_MQ_RQ_QUEUE_BUSY
:
784 list_add(&rq
->queuelist
, &rq_list
);
785 __blk_mq_requeue_request(rq
);
788 pr_err("blk-mq: bad return on queue: %d\n", ret
);
789 case BLK_MQ_RQ_QUEUE_ERROR
:
791 blk_mq_end_io(rq
, rq
->errors
);
795 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
800 hctx
->dispatched
[0]++;
801 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
802 hctx
->dispatched
[ilog2(queued
) + 1]++;
805 * Any items that need requeuing? Stuff them into hctx->dispatch,
806 * that is where we will continue on next queue run.
808 if (!list_empty(&rq_list
)) {
809 spin_lock(&hctx
->lock
);
810 list_splice(&rq_list
, &hctx
->dispatch
);
811 spin_unlock(&hctx
->lock
);
816 * It'd be great if the workqueue API had a way to pass
817 * in a mask and had some smarts for more clever placement.
818 * For now we just round-robin here, switching for every
819 * BLK_MQ_CPU_WORK_BATCH queued items.
821 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
823 int cpu
= hctx
->next_cpu
;
825 if (--hctx
->next_cpu_batch
<= 0) {
828 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
829 if (next_cpu
>= nr_cpu_ids
)
830 next_cpu
= cpumask_first(hctx
->cpumask
);
832 hctx
->next_cpu
= next_cpu
;
833 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
839 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
841 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
844 if (!async
&& cpumask_test_cpu(smp_processor_id(), hctx
->cpumask
))
845 __blk_mq_run_hw_queue(hctx
);
846 else if (hctx
->queue
->nr_hw_queues
== 1)
847 kblockd_schedule_delayed_work(&hctx
->run_work
, 0);
851 cpu
= blk_mq_hctx_next_cpu(hctx
);
852 kblockd_schedule_delayed_work_on(cpu
, &hctx
->run_work
, 0);
856 void blk_mq_run_queues(struct request_queue
*q
, bool async
)
858 struct blk_mq_hw_ctx
*hctx
;
861 queue_for_each_hw_ctx(q
, hctx
, i
) {
862 if ((!blk_mq_hctx_has_pending(hctx
) &&
863 list_empty_careful(&hctx
->dispatch
)) ||
864 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
868 blk_mq_run_hw_queue(hctx
, async
);
872 EXPORT_SYMBOL(blk_mq_run_queues
);
874 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
876 cancel_delayed_work(&hctx
->run_work
);
877 cancel_delayed_work(&hctx
->delay_work
);
878 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
880 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
882 void blk_mq_stop_hw_queues(struct request_queue
*q
)
884 struct blk_mq_hw_ctx
*hctx
;
887 queue_for_each_hw_ctx(q
, hctx
, i
)
888 blk_mq_stop_hw_queue(hctx
);
890 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
892 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
894 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
897 __blk_mq_run_hw_queue(hctx
);
900 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
902 void blk_mq_start_hw_queues(struct request_queue
*q
)
904 struct blk_mq_hw_ctx
*hctx
;
907 queue_for_each_hw_ctx(q
, hctx
, i
)
908 blk_mq_start_hw_queue(hctx
);
910 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
913 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
915 struct blk_mq_hw_ctx
*hctx
;
918 queue_for_each_hw_ctx(q
, hctx
, i
) {
919 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
922 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
924 blk_mq_run_hw_queue(hctx
, async
);
928 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
930 static void blk_mq_run_work_fn(struct work_struct
*work
)
932 struct blk_mq_hw_ctx
*hctx
;
934 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
936 __blk_mq_run_hw_queue(hctx
);
939 static void blk_mq_delay_work_fn(struct work_struct
*work
)
941 struct blk_mq_hw_ctx
*hctx
;
943 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
945 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
946 __blk_mq_run_hw_queue(hctx
);
949 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
951 unsigned long tmo
= msecs_to_jiffies(msecs
);
953 if (hctx
->queue
->nr_hw_queues
== 1)
954 kblockd_schedule_delayed_work(&hctx
->delay_work
, tmo
);
958 cpu
= blk_mq_hctx_next_cpu(hctx
);
959 kblockd_schedule_delayed_work_on(cpu
, &hctx
->delay_work
, tmo
);
962 EXPORT_SYMBOL(blk_mq_delay_queue
);
964 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
965 struct request
*rq
, bool at_head
)
967 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
969 trace_block_rq_insert(hctx
->queue
, rq
);
972 list_add(&rq
->queuelist
, &ctx
->rq_list
);
974 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
976 blk_mq_hctx_mark_pending(hctx
, ctx
);
979 * We do this early, to ensure we are on the right CPU.
984 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
987 struct request_queue
*q
= rq
->q
;
988 struct blk_mq_hw_ctx
*hctx
;
989 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
991 current_ctx
= blk_mq_get_ctx(q
);
992 if (!cpu_online(ctx
->cpu
))
993 rq
->mq_ctx
= ctx
= current_ctx
;
995 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
997 if (rq
->cmd_flags
& (REQ_FLUSH
| REQ_FUA
) &&
998 !(rq
->cmd_flags
& (REQ_FLUSH_SEQ
))) {
999 blk_insert_flush(rq
);
1001 spin_lock(&ctx
->lock
);
1002 __blk_mq_insert_request(hctx
, rq
, at_head
);
1003 spin_unlock(&ctx
->lock
);
1007 blk_mq_run_hw_queue(hctx
, async
);
1009 blk_mq_put_ctx(current_ctx
);
1012 static void blk_mq_insert_requests(struct request_queue
*q
,
1013 struct blk_mq_ctx
*ctx
,
1014 struct list_head
*list
,
1019 struct blk_mq_hw_ctx
*hctx
;
1020 struct blk_mq_ctx
*current_ctx
;
1022 trace_block_unplug(q
, depth
, !from_schedule
);
1024 current_ctx
= blk_mq_get_ctx(q
);
1026 if (!cpu_online(ctx
->cpu
))
1028 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1031 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1034 spin_lock(&ctx
->lock
);
1035 while (!list_empty(list
)) {
1038 rq
= list_first_entry(list
, struct request
, queuelist
);
1039 list_del_init(&rq
->queuelist
);
1041 __blk_mq_insert_request(hctx
, rq
, false);
1043 spin_unlock(&ctx
->lock
);
1045 blk_mq_run_hw_queue(hctx
, from_schedule
);
1046 blk_mq_put_ctx(current_ctx
);
1049 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1051 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1052 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1054 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1055 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1056 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1059 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1061 struct blk_mq_ctx
*this_ctx
;
1062 struct request_queue
*this_q
;
1065 LIST_HEAD(ctx_list
);
1068 list_splice_init(&plug
->mq_list
, &list
);
1070 list_sort(NULL
, &list
, plug_ctx_cmp
);
1076 while (!list_empty(&list
)) {
1077 rq
= list_entry_rq(list
.next
);
1078 list_del_init(&rq
->queuelist
);
1080 if (rq
->mq_ctx
!= this_ctx
) {
1082 blk_mq_insert_requests(this_q
, this_ctx
,
1087 this_ctx
= rq
->mq_ctx
;
1093 list_add_tail(&rq
->queuelist
, &ctx_list
);
1097 * If 'this_ctx' is set, we know we have entries to complete
1098 * on 'ctx_list'. Do those.
1101 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1106 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1108 init_request_from_bio(rq
, bio
);
1110 if (blk_do_io_stat(rq
)) {
1111 rq
->start_time
= jiffies
;
1112 blk_account_io_start(rq
, 1);
1116 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1117 struct blk_mq_ctx
*ctx
,
1118 struct request
*rq
, struct bio
*bio
)
1120 struct request_queue
*q
= hctx
->queue
;
1122 if (!(hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
)) {
1123 blk_mq_bio_to_request(rq
, bio
);
1124 spin_lock(&ctx
->lock
);
1126 __blk_mq_insert_request(hctx
, rq
, false);
1127 spin_unlock(&ctx
->lock
);
1130 spin_lock(&ctx
->lock
);
1131 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1132 blk_mq_bio_to_request(rq
, bio
);
1136 spin_unlock(&ctx
->lock
);
1137 __blk_mq_free_request(hctx
, ctx
, rq
);
1142 struct blk_map_ctx
{
1143 struct blk_mq_hw_ctx
*hctx
;
1144 struct blk_mq_ctx
*ctx
;
1147 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1149 struct blk_map_ctx
*data
)
1151 struct blk_mq_hw_ctx
*hctx
;
1152 struct blk_mq_ctx
*ctx
;
1154 int rw
= bio_data_dir(bio
);
1156 if (unlikely(blk_mq_queue_enter(q
))) {
1157 bio_endio(bio
, -EIO
);
1161 ctx
= blk_mq_get_ctx(q
);
1162 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1164 if (rw_is_sync(bio
->bi_rw
))
1167 trace_block_getrq(q
, bio
, rw
);
1168 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
, GFP_ATOMIC
, false);
1169 if (unlikely(!rq
)) {
1170 __blk_mq_run_hw_queue(hctx
);
1171 blk_mq_put_ctx(ctx
);
1172 trace_block_sleeprq(q
, bio
, rw
);
1174 ctx
= blk_mq_get_ctx(q
);
1175 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1176 rq
= __blk_mq_alloc_request(q
, hctx
, ctx
, rw
,
1177 __GFP_WAIT
|GFP_ATOMIC
, false);
1187 * Multiple hardware queue variant. This will not use per-process plugs,
1188 * but will attempt to bypass the hctx queueing if we can go straight to
1189 * hardware for SYNC IO.
1191 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1193 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1194 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1195 struct blk_map_ctx data
;
1198 blk_queue_bounce(q
, &bio
);
1200 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1201 bio_endio(bio
, -EIO
);
1205 rq
= blk_mq_map_request(q
, bio
, &data
);
1209 if (unlikely(is_flush_fua
)) {
1210 blk_mq_bio_to_request(rq
, bio
);
1211 blk_insert_flush(rq
);
1218 blk_mq_bio_to_request(rq
, bio
);
1219 blk_mq_start_request(rq
, true);
1223 * For OK queue, we are done. For error, kill it. Any other
1224 * error (busy), just add it to our list as we previously
1227 ret
= q
->mq_ops
->queue_rq(data
.hctx
, rq
);
1228 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1231 __blk_mq_requeue_request(rq
);
1233 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1235 blk_mq_end_io(rq
, rq
->errors
);
1241 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1243 * For a SYNC request, send it to the hardware immediately. For
1244 * an ASYNC request, just ensure that we run it later on. The
1245 * latter allows for merging opportunities and more efficient
1249 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1252 blk_mq_put_ctx(data
.ctx
);
1256 * Single hardware queue variant. This will attempt to use any per-process
1257 * plug for merging and IO deferral.
1259 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1261 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1262 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1263 unsigned int use_plug
, request_count
= 0;
1264 struct blk_map_ctx data
;
1268 * If we have multiple hardware queues, just go directly to
1269 * one of those for sync IO.
1271 use_plug
= !is_flush_fua
&& !is_sync
;
1273 blk_queue_bounce(q
, &bio
);
1275 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1276 bio_endio(bio
, -EIO
);
1280 if (use_plug
&& !blk_queue_nomerges(q
) &&
1281 blk_attempt_plug_merge(q
, bio
, &request_count
))
1284 rq
= blk_mq_map_request(q
, bio
, &data
);
1286 if (unlikely(is_flush_fua
)) {
1287 blk_mq_bio_to_request(rq
, bio
);
1288 blk_insert_flush(rq
);
1293 * A task plug currently exists. Since this is completely lockless,
1294 * utilize that to temporarily store requests until the task is
1295 * either done or scheduled away.
1298 struct blk_plug
*plug
= current
->plug
;
1301 blk_mq_bio_to_request(rq
, bio
);
1302 if (list_empty(&plug
->mq_list
))
1303 trace_block_plug(q
);
1304 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1305 blk_flush_plug_list(plug
, false);
1306 trace_block_plug(q
);
1308 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1309 blk_mq_put_ctx(data
.ctx
);
1314 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1316 * For a SYNC request, send it to the hardware immediately. For
1317 * an ASYNC request, just ensure that we run it later on. The
1318 * latter allows for merging opportunities and more efficient
1322 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1325 blk_mq_put_ctx(data
.ctx
);
1329 * Default mapping to a software queue, since we use one per CPU.
1331 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1333 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1335 EXPORT_SYMBOL(blk_mq_map_queue
);
1337 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1338 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1342 if (tags
->rqs
&& set
->ops
->exit_request
) {
1345 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1348 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1353 while (!list_empty(&tags
->page_list
)) {
1354 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1355 list_del_init(&page
->lru
);
1356 __free_pages(page
, page
->private);
1361 blk_mq_free_tags(tags
);
1364 static size_t order_to_size(unsigned int order
)
1366 return (size_t)PAGE_SIZE
<< order
;
1369 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1370 unsigned int hctx_idx
)
1372 struct blk_mq_tags
*tags
;
1373 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1374 size_t rq_size
, left
;
1376 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1381 INIT_LIST_HEAD(&tags
->page_list
);
1383 tags
->rqs
= kmalloc_node(set
->queue_depth
* sizeof(struct request
*),
1384 GFP_KERNEL
, set
->numa_node
);
1386 blk_mq_free_tags(tags
);
1391 * rq_size is the size of the request plus driver payload, rounded
1392 * to the cacheline size
1394 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1396 left
= rq_size
* set
->queue_depth
;
1398 for (i
= 0; i
< set
->queue_depth
; ) {
1399 int this_order
= max_order
;
1404 while (left
< order_to_size(this_order
- 1) && this_order
)
1408 page
= alloc_pages_node(set
->numa_node
, GFP_KERNEL
,
1414 if (order_to_size(this_order
) < rq_size
)
1421 page
->private = this_order
;
1422 list_add_tail(&page
->lru
, &tags
->page_list
);
1424 p
= page_address(page
);
1425 entries_per_page
= order_to_size(this_order
) / rq_size
;
1426 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1427 left
-= to_do
* rq_size
;
1428 for (j
= 0; j
< to_do
; j
++) {
1430 if (set
->ops
->init_request
) {
1431 if (set
->ops
->init_request(set
->driver_data
,
1432 tags
->rqs
[i
], hctx_idx
, i
,
1445 pr_warn("%s: failed to allocate requests\n", __func__
);
1446 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1450 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1455 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1457 unsigned int bpw
= 8, total
, num_maps
, i
;
1459 bitmap
->bits_per_word
= bpw
;
1461 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1462 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1467 bitmap
->map_size
= num_maps
;
1470 for (i
= 0; i
< num_maps
; i
++) {
1471 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1472 total
-= bitmap
->map
[i
].depth
;
1478 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1480 struct request_queue
*q
= hctx
->queue
;
1481 struct blk_mq_ctx
*ctx
;
1485 * Move ctx entries to new CPU, if this one is going away.
1487 ctx
= __blk_mq_get_ctx(q
, cpu
);
1489 spin_lock(&ctx
->lock
);
1490 if (!list_empty(&ctx
->rq_list
)) {
1491 list_splice_init(&ctx
->rq_list
, &tmp
);
1492 blk_mq_hctx_clear_pending(hctx
, ctx
);
1494 spin_unlock(&ctx
->lock
);
1496 if (list_empty(&tmp
))
1499 ctx
= blk_mq_get_ctx(q
);
1500 spin_lock(&ctx
->lock
);
1502 while (!list_empty(&tmp
)) {
1505 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1507 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1510 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1511 blk_mq_hctx_mark_pending(hctx
, ctx
);
1513 spin_unlock(&ctx
->lock
);
1515 blk_mq_run_hw_queue(hctx
, true);
1516 blk_mq_put_ctx(ctx
);
1520 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1522 struct request_queue
*q
= hctx
->queue
;
1523 struct blk_mq_tag_set
*set
= q
->tag_set
;
1525 if (set
->tags
[hctx
->queue_num
])
1528 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1529 if (!set
->tags
[hctx
->queue_num
])
1532 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1536 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1539 struct blk_mq_hw_ctx
*hctx
= data
;
1541 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1542 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1543 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1544 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1549 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1550 struct blk_mq_tag_set
*set
, int nr_queue
)
1552 struct blk_mq_hw_ctx
*hctx
;
1555 queue_for_each_hw_ctx(q
, hctx
, i
) {
1559 if (set
->ops
->exit_hctx
)
1560 set
->ops
->exit_hctx(hctx
, i
);
1562 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1564 blk_mq_free_bitmap(&hctx
->ctx_map
);
1569 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1570 struct blk_mq_tag_set
*set
)
1572 struct blk_mq_hw_ctx
*hctx
;
1575 queue_for_each_hw_ctx(q
, hctx
, i
) {
1576 free_cpumask_var(hctx
->cpumask
);
1581 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1582 struct blk_mq_tag_set
*set
)
1584 struct blk_mq_hw_ctx
*hctx
;
1588 * Initialize hardware queues
1590 queue_for_each_hw_ctx(q
, hctx
, i
) {
1593 node
= hctx
->numa_node
;
1594 if (node
== NUMA_NO_NODE
)
1595 node
= hctx
->numa_node
= set
->numa_node
;
1597 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1598 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1599 spin_lock_init(&hctx
->lock
);
1600 INIT_LIST_HEAD(&hctx
->dispatch
);
1602 hctx
->queue_num
= i
;
1603 hctx
->flags
= set
->flags
;
1604 hctx
->cmd_size
= set
->cmd_size
;
1606 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1607 blk_mq_hctx_notify
, hctx
);
1608 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1610 hctx
->tags
= set
->tags
[i
];
1613 * Allocate space for all possible cpus to avoid allocation in
1616 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1621 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1626 if (set
->ops
->init_hctx
&&
1627 set
->ops
->init_hctx(hctx
, set
->driver_data
, i
))
1631 if (i
== q
->nr_hw_queues
)
1637 blk_mq_exit_hw_queues(q
, set
, i
);
1642 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1643 unsigned int nr_hw_queues
)
1647 for_each_possible_cpu(i
) {
1648 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1649 struct blk_mq_hw_ctx
*hctx
;
1651 memset(__ctx
, 0, sizeof(*__ctx
));
1653 spin_lock_init(&__ctx
->lock
);
1654 INIT_LIST_HEAD(&__ctx
->rq_list
);
1657 /* If the cpu isn't online, the cpu is mapped to first hctx */
1661 hctx
= q
->mq_ops
->map_queue(q
, i
);
1662 cpumask_set_cpu(i
, hctx
->cpumask
);
1666 * Set local node, IFF we have more than one hw queue. If
1667 * not, we remain on the home node of the device
1669 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1670 hctx
->numa_node
= cpu_to_node(i
);
1674 static void blk_mq_map_swqueue(struct request_queue
*q
)
1677 struct blk_mq_hw_ctx
*hctx
;
1678 struct blk_mq_ctx
*ctx
;
1680 queue_for_each_hw_ctx(q
, hctx
, i
) {
1681 cpumask_clear(hctx
->cpumask
);
1686 * Map software to hardware queues
1688 queue_for_each_ctx(q
, ctx
, i
) {
1689 /* If the cpu isn't online, the cpu is mapped to first hctx */
1693 hctx
= q
->mq_ops
->map_queue(q
, i
);
1694 cpumask_set_cpu(i
, hctx
->cpumask
);
1695 ctx
->index_hw
= hctx
->nr_ctx
;
1696 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1699 queue_for_each_hw_ctx(q
, hctx
, i
) {
1701 * If not software queues are mapped to this hardware queue,
1702 * disable it and free the request entries
1704 if (!hctx
->nr_ctx
) {
1705 struct blk_mq_tag_set
*set
= q
->tag_set
;
1708 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1709 set
->tags
[i
] = NULL
;
1716 * Initialize batch roundrobin counts
1718 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1719 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1723 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1725 struct blk_mq_hw_ctx
*hctx
;
1726 struct request_queue
*q
;
1730 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1735 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1736 blk_mq_freeze_queue(q
);
1738 queue_for_each_hw_ctx(q
, hctx
, i
) {
1740 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1742 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1744 blk_mq_unfreeze_queue(q
);
1748 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1750 struct blk_mq_tag_set
*set
= q
->tag_set
;
1752 blk_mq_freeze_queue(q
);
1754 mutex_lock(&set
->tag_list_lock
);
1755 list_del_init(&q
->tag_set_list
);
1756 blk_mq_update_tag_set_depth(set
);
1757 mutex_unlock(&set
->tag_list_lock
);
1759 blk_mq_unfreeze_queue(q
);
1762 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1763 struct request_queue
*q
)
1767 mutex_lock(&set
->tag_list_lock
);
1768 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1769 blk_mq_update_tag_set_depth(set
);
1770 mutex_unlock(&set
->tag_list_lock
);
1773 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1775 struct blk_mq_hw_ctx
**hctxs
;
1776 struct blk_mq_ctx
*ctx
;
1777 struct request_queue
*q
;
1781 ctx
= alloc_percpu(struct blk_mq_ctx
);
1783 return ERR_PTR(-ENOMEM
);
1785 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1791 map
= blk_mq_make_queue_map(set
);
1795 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1796 int node
= blk_mq_hw_queue_to_node(map
, i
);
1798 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1803 if (!zalloc_cpumask_var(&hctxs
[i
]->cpumask
, GFP_KERNEL
))
1806 atomic_set(&hctxs
[i
]->nr_active
, 0);
1807 hctxs
[i
]->numa_node
= node
;
1808 hctxs
[i
]->queue_num
= i
;
1811 q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1815 if (percpu_counter_init(&q
->mq_usage_counter
, 0))
1818 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1819 blk_queue_rq_timeout(q
, 30000);
1821 q
->nr_queues
= nr_cpu_ids
;
1822 q
->nr_hw_queues
= set
->nr_hw_queues
;
1826 q
->queue_hw_ctx
= hctxs
;
1828 q
->mq_ops
= set
->ops
;
1829 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
1831 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
1832 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
1834 q
->sg_reserved_size
= INT_MAX
;
1836 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
1837 INIT_LIST_HEAD(&q
->requeue_list
);
1838 spin_lock_init(&q
->requeue_lock
);
1840 if (q
->nr_hw_queues
> 1)
1841 blk_queue_make_request(q
, blk_mq_make_request
);
1843 blk_queue_make_request(q
, blk_sq_make_request
);
1845 blk_queue_rq_timed_out(q
, blk_mq_rq_timed_out
);
1847 blk_queue_rq_timeout(q
, set
->timeout
);
1850 * Do this after blk_queue_make_request() overrides it...
1852 q
->nr_requests
= set
->queue_depth
;
1854 if (set
->ops
->complete
)
1855 blk_queue_softirq_done(q
, set
->ops
->complete
);
1857 blk_mq_init_flush(q
);
1858 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
1860 q
->flush_rq
= kzalloc(round_up(sizeof(struct request
) +
1861 set
->cmd_size
, cache_line_size()),
1866 if (blk_mq_init_hw_queues(q
, set
))
1869 mutex_lock(&all_q_mutex
);
1870 list_add_tail(&q
->all_q_node
, &all_q_list
);
1871 mutex_unlock(&all_q_mutex
);
1873 blk_mq_add_queue_tag_set(set
, q
);
1875 blk_mq_map_swqueue(q
);
1882 blk_cleanup_queue(q
);
1885 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1888 free_cpumask_var(hctxs
[i
]->cpumask
);
1895 return ERR_PTR(-ENOMEM
);
1897 EXPORT_SYMBOL(blk_mq_init_queue
);
1899 void blk_mq_free_queue(struct request_queue
*q
)
1901 struct blk_mq_tag_set
*set
= q
->tag_set
;
1903 blk_mq_del_queue_tag_set(q
);
1905 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
1906 blk_mq_free_hw_queues(q
, set
);
1908 percpu_counter_destroy(&q
->mq_usage_counter
);
1910 free_percpu(q
->queue_ctx
);
1911 kfree(q
->queue_hw_ctx
);
1914 q
->queue_ctx
= NULL
;
1915 q
->queue_hw_ctx
= NULL
;
1918 mutex_lock(&all_q_mutex
);
1919 list_del_init(&q
->all_q_node
);
1920 mutex_unlock(&all_q_mutex
);
1923 /* Basically redo blk_mq_init_queue with queue frozen */
1924 static void blk_mq_queue_reinit(struct request_queue
*q
)
1926 blk_mq_freeze_queue(q
);
1928 blk_mq_sysfs_unregister(q
);
1930 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
1933 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
1934 * we should change hctx numa_node according to new topology (this
1935 * involves free and re-allocate memory, worthy doing?)
1938 blk_mq_map_swqueue(q
);
1940 blk_mq_sysfs_register(q
);
1942 blk_mq_unfreeze_queue(q
);
1945 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
1946 unsigned long action
, void *hcpu
)
1948 struct request_queue
*q
;
1951 * Before new mappings are established, hotadded cpu might already
1952 * start handling requests. This doesn't break anything as we map
1953 * offline CPUs to first hardware queue. We will re-init the queue
1954 * below to get optimal settings.
1956 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
1957 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
1960 mutex_lock(&all_q_mutex
);
1961 list_for_each_entry(q
, &all_q_list
, all_q_node
)
1962 blk_mq_queue_reinit(q
);
1963 mutex_unlock(&all_q_mutex
);
1967 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
1971 if (!set
->nr_hw_queues
)
1973 if (!set
->queue_depth
|| set
->queue_depth
> BLK_MQ_MAX_DEPTH
)
1975 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
1978 if (!set
->nr_hw_queues
|| !set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
1982 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
1983 sizeof(struct blk_mq_tags
*),
1984 GFP_KERNEL
, set
->numa_node
);
1988 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1989 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1994 mutex_init(&set
->tag_list_lock
);
1995 INIT_LIST_HEAD(&set
->tag_list
);
2001 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2005 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2007 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2011 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2013 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2018 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2020 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2022 struct blk_mq_tag_set
*set
= q
->tag_set
;
2023 struct blk_mq_hw_ctx
*hctx
;
2026 if (!set
|| nr
> set
->queue_depth
)
2030 queue_for_each_hw_ctx(q
, hctx
, i
) {
2031 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2037 q
->nr_requests
= nr
;
2042 void blk_mq_disable_hotplug(void)
2044 mutex_lock(&all_q_mutex
);
2047 void blk_mq_enable_hotplug(void)
2049 mutex_unlock(&all_q_mutex
);
2052 static int __init
blk_mq_init(void)
2056 /* Must be called after percpu_counter_hotcpu_callback() */
2057 hotcpu_notifier(blk_mq_queue_reinit_notify
, -10);
2061 subsys_initcall(blk_mq_init
);