2 * Block multiqueue core code
4 * Copyright (C) 2013-2014 Jens Axboe
5 * Copyright (C) 2013-2014 Christoph Hellwig
7 #include <linux/kernel.h>
8 #include <linux/module.h>
9 #include <linux/backing-dev.h>
10 #include <linux/bio.h>
11 #include <linux/blkdev.h>
13 #include <linux/init.h>
14 #include <linux/slab.h>
15 #include <linux/workqueue.h>
16 #include <linux/smp.h>
17 #include <linux/llist.h>
18 #include <linux/list_sort.h>
19 #include <linux/cpu.h>
20 #include <linux/cache.h>
21 #include <linux/sched/sysctl.h>
22 #include <linux/delay.h>
23 #include <linux/crash_dump.h>
25 #include <trace/events/block.h>
27 #include <linux/blk-mq.h>
30 #include "blk-mq-tag.h"
32 static DEFINE_MUTEX(all_q_mutex
);
33 static LIST_HEAD(all_q_list
);
35 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
);
38 * Check if any of the ctx's have pending work in this hardware queue
40 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx
*hctx
)
44 for (i
= 0; i
< hctx
->ctx_map
.size
; i
++)
45 if (hctx
->ctx_map
.map
[i
].word
)
51 static inline struct blk_align_bitmap
*get_bm(struct blk_mq_hw_ctx
*hctx
,
52 struct blk_mq_ctx
*ctx
)
54 return &hctx
->ctx_map
.map
[ctx
->index_hw
/ hctx
->ctx_map
.bits_per_word
];
57 #define CTX_TO_BIT(hctx, ctx) \
58 ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1))
61 * Mark this ctx as having pending work in this hardware queue
63 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx
*hctx
,
64 struct blk_mq_ctx
*ctx
)
66 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
68 if (!test_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
))
69 set_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
72 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx
*hctx
,
73 struct blk_mq_ctx
*ctx
)
75 struct blk_align_bitmap
*bm
= get_bm(hctx
, ctx
);
77 clear_bit(CTX_TO_BIT(hctx
, ctx
), &bm
->word
);
80 static int blk_mq_queue_enter(struct request_queue
*q
, gfp_t gfp
)
85 if (percpu_ref_tryget_live(&q
->mq_usage_counter
))
88 if (!(gfp
& __GFP_WAIT
))
91 ret
= wait_event_interruptible(q
->mq_freeze_wq
,
92 !q
->mq_freeze_depth
|| blk_queue_dying(q
));
93 if (blk_queue_dying(q
))
100 static void blk_mq_queue_exit(struct request_queue
*q
)
102 percpu_ref_put(&q
->mq_usage_counter
);
105 static void blk_mq_usage_counter_release(struct percpu_ref
*ref
)
107 struct request_queue
*q
=
108 container_of(ref
, struct request_queue
, mq_usage_counter
);
110 wake_up_all(&q
->mq_freeze_wq
);
113 void blk_mq_freeze_queue_start(struct request_queue
*q
)
117 spin_lock_irq(q
->queue_lock
);
118 freeze
= !q
->mq_freeze_depth
++;
119 spin_unlock_irq(q
->queue_lock
);
122 percpu_ref_kill(&q
->mq_usage_counter
);
123 blk_mq_run_hw_queues(q
, false);
126 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start
);
128 static void blk_mq_freeze_queue_wait(struct request_queue
*q
)
130 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->mq_usage_counter
));
134 * Guarantee no request is in use, so we can change any data structure of
135 * the queue afterward.
137 void blk_mq_freeze_queue(struct request_queue
*q
)
139 blk_mq_freeze_queue_start(q
);
140 blk_mq_freeze_queue_wait(q
);
142 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
144 void blk_mq_unfreeze_queue(struct request_queue
*q
)
148 spin_lock_irq(q
->queue_lock
);
149 wake
= !--q
->mq_freeze_depth
;
150 WARN_ON_ONCE(q
->mq_freeze_depth
< 0);
151 spin_unlock_irq(q
->queue_lock
);
153 percpu_ref_reinit(&q
->mq_usage_counter
);
154 wake_up_all(&q
->mq_freeze_wq
);
157 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
159 void blk_mq_wake_waiters(struct request_queue
*q
)
161 struct blk_mq_hw_ctx
*hctx
;
164 queue_for_each_hw_ctx(q
, hctx
, i
)
165 if (blk_mq_hw_queue_mapped(hctx
))
166 blk_mq_tag_wakeup_all(hctx
->tags
, true);
169 * If we are called because the queue has now been marked as
170 * dying, we need to ensure that processes currently waiting on
171 * the queue are notified as well.
173 wake_up_all(&q
->mq_freeze_wq
);
176 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
178 return blk_mq_has_free_tags(hctx
->tags
);
180 EXPORT_SYMBOL(blk_mq_can_queue
);
182 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
183 struct request
*rq
, unsigned int rw_flags
)
185 if (blk_queue_io_stat(q
))
186 rw_flags
|= REQ_IO_STAT
;
188 INIT_LIST_HEAD(&rq
->queuelist
);
189 /* csd/requeue_work/fifo_time is initialized before use */
192 rq
->cmd_flags
|= rw_flags
;
193 /* do not touch atomic flags, it needs atomic ops against the timer */
195 INIT_HLIST_NODE(&rq
->hash
);
196 RB_CLEAR_NODE(&rq
->rb_node
);
199 rq
->start_time
= jiffies
;
200 #ifdef CONFIG_BLK_CGROUP
202 set_start_time_ns(rq
);
203 rq
->io_start_time_ns
= 0;
205 rq
->nr_phys_segments
= 0;
206 #if defined(CONFIG_BLK_DEV_INTEGRITY)
207 rq
->nr_integrity_segments
= 0;
210 /* tag was already set */
220 INIT_LIST_HEAD(&rq
->timeout_list
);
224 rq
->end_io_data
= NULL
;
227 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
230 static struct request
*
231 __blk_mq_alloc_request(struct blk_mq_alloc_data
*data
, int rw
)
236 tag
= blk_mq_get_tag(data
);
237 if (tag
!= BLK_MQ_TAG_FAIL
) {
238 rq
= data
->hctx
->tags
->rqs
[tag
];
240 if (blk_mq_tag_busy(data
->hctx
)) {
241 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
242 atomic_inc(&data
->hctx
->nr_active
);
246 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, rw
);
253 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
256 struct blk_mq_ctx
*ctx
;
257 struct blk_mq_hw_ctx
*hctx
;
259 struct blk_mq_alloc_data alloc_data
;
262 ret
= blk_mq_queue_enter(q
, gfp
);
266 ctx
= blk_mq_get_ctx(q
);
267 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
268 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
& ~__GFP_WAIT
,
269 reserved
, ctx
, hctx
);
271 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
272 if (!rq
&& (gfp
& __GFP_WAIT
)) {
273 __blk_mq_run_hw_queue(hctx
);
276 ctx
= blk_mq_get_ctx(q
);
277 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
278 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
, reserved
, ctx
,
280 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
281 ctx
= alloc_data
.ctx
;
285 blk_mq_queue_exit(q
);
286 return ERR_PTR(-EWOULDBLOCK
);
290 EXPORT_SYMBOL(blk_mq_alloc_request
);
292 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
293 struct blk_mq_ctx
*ctx
, struct request
*rq
)
295 const int tag
= rq
->tag
;
296 struct request_queue
*q
= rq
->q
;
298 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
299 atomic_dec(&hctx
->nr_active
);
302 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
303 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
304 blk_mq_queue_exit(q
);
307 void blk_mq_free_hctx_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
309 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
311 ctx
->rq_completed
[rq_is_sync(rq
)]++;
312 __blk_mq_free_request(hctx
, ctx
, rq
);
315 EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request
);
317 void blk_mq_free_request(struct request
*rq
)
319 struct blk_mq_hw_ctx
*hctx
;
320 struct request_queue
*q
= rq
->q
;
322 hctx
= q
->mq_ops
->map_queue(q
, rq
->mq_ctx
->cpu
);
323 blk_mq_free_hctx_request(hctx
, rq
);
325 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
327 inline void __blk_mq_end_request(struct request
*rq
, int error
)
329 blk_account_io_done(rq
);
332 rq
->end_io(rq
, error
);
334 if (unlikely(blk_bidi_rq(rq
)))
335 blk_mq_free_request(rq
->next_rq
);
336 blk_mq_free_request(rq
);
339 EXPORT_SYMBOL(__blk_mq_end_request
);
341 void blk_mq_end_request(struct request
*rq
, int error
)
343 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
345 __blk_mq_end_request(rq
, error
);
347 EXPORT_SYMBOL(blk_mq_end_request
);
349 static void __blk_mq_complete_request_remote(void *data
)
351 struct request
*rq
= data
;
353 rq
->q
->softirq_done_fn(rq
);
356 static void blk_mq_ipi_complete_request(struct request
*rq
)
358 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
362 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
363 rq
->q
->softirq_done_fn(rq
);
368 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
369 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
371 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
372 rq
->csd
.func
= __blk_mq_complete_request_remote
;
375 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
377 rq
->q
->softirq_done_fn(rq
);
382 void __blk_mq_complete_request(struct request
*rq
)
384 struct request_queue
*q
= rq
->q
;
386 if (!q
->softirq_done_fn
)
387 blk_mq_end_request(rq
, rq
->errors
);
389 blk_mq_ipi_complete_request(rq
);
393 * blk_mq_complete_request - end I/O on a request
394 * @rq: the request being processed
397 * Ends all I/O on a request. It does not handle partial completions.
398 * The actual completion happens out-of-order, through a IPI handler.
400 void blk_mq_complete_request(struct request
*rq
)
402 struct request_queue
*q
= rq
->q
;
404 if (unlikely(blk_should_fake_timeout(q
)))
406 if (!blk_mark_rq_complete(rq
))
407 __blk_mq_complete_request(rq
);
409 EXPORT_SYMBOL(blk_mq_complete_request
);
411 int blk_mq_request_started(struct request
*rq
)
413 return test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
415 EXPORT_SYMBOL_GPL(blk_mq_request_started
);
417 void blk_mq_start_request(struct request
*rq
)
419 struct request_queue
*q
= rq
->q
;
421 trace_block_rq_issue(q
, rq
);
423 rq
->resid_len
= blk_rq_bytes(rq
);
424 if (unlikely(blk_bidi_rq(rq
)))
425 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
430 * Ensure that ->deadline is visible before set the started
431 * flag and clear the completed flag.
433 smp_mb__before_atomic();
436 * Mark us as started and clear complete. Complete might have been
437 * set if requeue raced with timeout, which then marked it as
438 * complete. So be sure to clear complete again when we start
439 * the request, otherwise we'll ignore the completion event.
441 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
442 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
443 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
444 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
446 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
448 * Make sure space for the drain appears. We know we can do
449 * this because max_hw_segments has been adjusted to be one
450 * fewer than the device can handle.
452 rq
->nr_phys_segments
++;
455 EXPORT_SYMBOL(blk_mq_start_request
);
457 static void __blk_mq_requeue_request(struct request
*rq
)
459 struct request_queue
*q
= rq
->q
;
461 trace_block_rq_requeue(q
, rq
);
463 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
464 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
465 rq
->nr_phys_segments
--;
469 void blk_mq_requeue_request(struct request
*rq
)
471 __blk_mq_requeue_request(rq
);
473 BUG_ON(blk_queued_rq(rq
));
474 blk_mq_add_to_requeue_list(rq
, true);
476 EXPORT_SYMBOL(blk_mq_requeue_request
);
478 static void blk_mq_requeue_work(struct work_struct
*work
)
480 struct request_queue
*q
=
481 container_of(work
, struct request_queue
, requeue_work
);
483 struct request
*rq
, *next
;
486 spin_lock_irqsave(&q
->requeue_lock
, flags
);
487 list_splice_init(&q
->requeue_list
, &rq_list
);
488 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
490 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
491 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
494 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
495 list_del_init(&rq
->queuelist
);
496 blk_mq_insert_request(rq
, true, false, false);
499 while (!list_empty(&rq_list
)) {
500 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
501 list_del_init(&rq
->queuelist
);
502 blk_mq_insert_request(rq
, false, false, false);
506 * Use the start variant of queue running here, so that running
507 * the requeue work will kick stopped queues.
509 blk_mq_start_hw_queues(q
);
512 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
514 struct request_queue
*q
= rq
->q
;
518 * We abuse this flag that is otherwise used by the I/O scheduler to
519 * request head insertation from the workqueue.
521 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
523 spin_lock_irqsave(&q
->requeue_lock
, flags
);
525 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
526 list_add(&rq
->queuelist
, &q
->requeue_list
);
528 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
530 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
532 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
534 void blk_mq_cancel_requeue_work(struct request_queue
*q
)
536 cancel_work_sync(&q
->requeue_work
);
538 EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work
);
540 void blk_mq_kick_requeue_list(struct request_queue
*q
)
542 kblockd_schedule_work(&q
->requeue_work
);
544 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
546 void blk_mq_abort_requeue_list(struct request_queue
*q
)
551 spin_lock_irqsave(&q
->requeue_lock
, flags
);
552 list_splice_init(&q
->requeue_list
, &rq_list
);
553 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
555 while (!list_empty(&rq_list
)) {
558 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
559 list_del_init(&rq
->queuelist
);
561 blk_mq_end_request(rq
, rq
->errors
);
564 EXPORT_SYMBOL(blk_mq_abort_requeue_list
);
566 static inline bool is_flush_request(struct request
*rq
,
567 struct blk_flush_queue
*fq
, unsigned int tag
)
569 return ((rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
570 fq
->flush_rq
->tag
== tag
);
573 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
575 struct request
*rq
= tags
->rqs
[tag
];
576 /* mq_ctx of flush rq is always cloned from the corresponding req */
577 struct blk_flush_queue
*fq
= blk_get_flush_queue(rq
->q
, rq
->mq_ctx
);
579 if (!is_flush_request(rq
, fq
, tag
))
584 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
586 struct blk_mq_timeout_data
{
588 unsigned int next_set
;
591 void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
593 struct blk_mq_ops
*ops
= req
->q
->mq_ops
;
594 enum blk_eh_timer_return ret
= BLK_EH_RESET_TIMER
;
597 * We know that complete is set at this point. If STARTED isn't set
598 * anymore, then the request isn't active and the "timeout" should
599 * just be ignored. This can happen due to the bitflag ordering.
600 * Timeout first checks if STARTED is set, and if it is, assumes
601 * the request is active. But if we race with completion, then
602 * we both flags will get cleared. So check here again, and ignore
603 * a timeout event with a request that isn't active.
605 if (!test_bit(REQ_ATOM_STARTED
, &req
->atomic_flags
))
609 ret
= ops
->timeout(req
, reserved
);
613 __blk_mq_complete_request(req
);
615 case BLK_EH_RESET_TIMER
:
617 blk_clear_rq_complete(req
);
619 case BLK_EH_NOT_HANDLED
:
622 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
627 static void blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
628 struct request
*rq
, void *priv
, bool reserved
)
630 struct blk_mq_timeout_data
*data
= priv
;
632 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
634 * If a request wasn't started before the queue was
635 * marked dying, kill it here or it'll go unnoticed.
637 if (unlikely(blk_queue_dying(rq
->q
))) {
639 blk_mq_complete_request(rq
);
643 if (rq
->cmd_flags
& REQ_NO_TIMEOUT
)
646 if (time_after_eq(jiffies
, rq
->deadline
)) {
647 if (!blk_mark_rq_complete(rq
))
648 blk_mq_rq_timed_out(rq
, reserved
);
649 } else if (!data
->next_set
|| time_after(data
->next
, rq
->deadline
)) {
650 data
->next
= rq
->deadline
;
655 static void blk_mq_rq_timer(unsigned long priv
)
657 struct request_queue
*q
= (struct request_queue
*)priv
;
658 struct blk_mq_timeout_data data
= {
662 struct blk_mq_hw_ctx
*hctx
;
665 queue_for_each_hw_ctx(q
, hctx
, i
) {
667 * If not software queues are currently mapped to this
668 * hardware queue, there's nothing to check
670 if (!blk_mq_hw_queue_mapped(hctx
))
673 blk_mq_tag_busy_iter(hctx
, blk_mq_check_expired
, &data
);
677 data
.next
= blk_rq_timeout(round_jiffies_up(data
.next
));
678 mod_timer(&q
->timeout
, data
.next
);
680 queue_for_each_hw_ctx(q
, hctx
, i
)
681 blk_mq_tag_idle(hctx
);
686 * Reverse check our software queue for entries that we could potentially
687 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
688 * too much time checking for merges.
690 static bool blk_mq_attempt_merge(struct request_queue
*q
,
691 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
696 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
702 if (!blk_rq_merge_ok(rq
, bio
))
705 el_ret
= blk_try_merge(rq
, bio
);
706 if (el_ret
== ELEVATOR_BACK_MERGE
) {
707 if (bio_attempt_back_merge(q
, rq
, bio
)) {
712 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
713 if (bio_attempt_front_merge(q
, rq
, bio
)) {
725 * Process software queues that have been marked busy, splicing them
726 * to the for-dispatch
728 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
730 struct blk_mq_ctx
*ctx
;
733 for (i
= 0; i
< hctx
->ctx_map
.size
; i
++) {
734 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
735 unsigned int off
, bit
;
741 off
= i
* hctx
->ctx_map
.bits_per_word
;
743 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
744 if (bit
>= bm
->depth
)
747 ctx
= hctx
->ctxs
[bit
+ off
];
748 clear_bit(bit
, &bm
->word
);
749 spin_lock(&ctx
->lock
);
750 list_splice_tail_init(&ctx
->rq_list
, list
);
751 spin_unlock(&ctx
->lock
);
759 * Run this hardware queue, pulling any software queues mapped to it in.
760 * Note that this function currently has various problems around ordering
761 * of IO. In particular, we'd like FIFO behaviour on handling existing
762 * items on the hctx->dispatch list. Ignore that for now.
764 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
766 struct request_queue
*q
= hctx
->queue
;
769 LIST_HEAD(driver_list
);
770 struct list_head
*dptr
;
773 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
775 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
781 * Touch any software queue that has pending entries.
783 flush_busy_ctxs(hctx
, &rq_list
);
786 * If we have previous entries on our dispatch list, grab them
787 * and stuff them at the front for more fair dispatch.
789 if (!list_empty_careful(&hctx
->dispatch
)) {
790 spin_lock(&hctx
->lock
);
791 if (!list_empty(&hctx
->dispatch
))
792 list_splice_init(&hctx
->dispatch
, &rq_list
);
793 spin_unlock(&hctx
->lock
);
797 * Start off with dptr being NULL, so we start the first request
798 * immediately, even if we have more pending.
803 * Now process all the entries, sending them to the driver.
806 while (!list_empty(&rq_list
)) {
807 struct blk_mq_queue_data bd
;
810 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
811 list_del_init(&rq
->queuelist
);
815 bd
.last
= list_empty(&rq_list
);
817 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
819 case BLK_MQ_RQ_QUEUE_OK
:
822 case BLK_MQ_RQ_QUEUE_BUSY
:
823 list_add(&rq
->queuelist
, &rq_list
);
824 __blk_mq_requeue_request(rq
);
827 pr_err("blk-mq: bad return on queue: %d\n", ret
);
828 case BLK_MQ_RQ_QUEUE_ERROR
:
830 blk_mq_end_request(rq
, rq
->errors
);
834 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
838 * We've done the first request. If we have more than 1
839 * left in the list, set dptr to defer issue.
841 if (!dptr
&& rq_list
.next
!= rq_list
.prev
)
846 hctx
->dispatched
[0]++;
847 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
848 hctx
->dispatched
[ilog2(queued
) + 1]++;
851 * Any items that need requeuing? Stuff them into hctx->dispatch,
852 * that is where we will continue on next queue run.
854 if (!list_empty(&rq_list
)) {
855 spin_lock(&hctx
->lock
);
856 list_splice(&rq_list
, &hctx
->dispatch
);
857 spin_unlock(&hctx
->lock
);
862 * It'd be great if the workqueue API had a way to pass
863 * in a mask and had some smarts for more clever placement.
864 * For now we just round-robin here, switching for every
865 * BLK_MQ_CPU_WORK_BATCH queued items.
867 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
869 if (hctx
->queue
->nr_hw_queues
== 1)
870 return WORK_CPU_UNBOUND
;
872 if (--hctx
->next_cpu_batch
<= 0) {
873 int cpu
= hctx
->next_cpu
, next_cpu
;
875 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
876 if (next_cpu
>= nr_cpu_ids
)
877 next_cpu
= cpumask_first(hctx
->cpumask
);
879 hctx
->next_cpu
= next_cpu
;
880 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
885 return hctx
->next_cpu
;
888 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
890 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
) ||
891 !blk_mq_hw_queue_mapped(hctx
)))
896 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
897 __blk_mq_run_hw_queue(hctx
);
905 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
909 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
911 struct blk_mq_hw_ctx
*hctx
;
914 queue_for_each_hw_ctx(q
, hctx
, i
) {
915 if ((!blk_mq_hctx_has_pending(hctx
) &&
916 list_empty_careful(&hctx
->dispatch
)) ||
917 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
920 blk_mq_run_hw_queue(hctx
, async
);
923 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
925 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
927 cancel_delayed_work(&hctx
->run_work
);
928 cancel_delayed_work(&hctx
->delay_work
);
929 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
931 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
933 void blk_mq_stop_hw_queues(struct request_queue
*q
)
935 struct blk_mq_hw_ctx
*hctx
;
938 queue_for_each_hw_ctx(q
, hctx
, i
)
939 blk_mq_stop_hw_queue(hctx
);
941 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
943 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
945 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
947 blk_mq_run_hw_queue(hctx
, false);
949 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
951 void blk_mq_start_hw_queues(struct request_queue
*q
)
953 struct blk_mq_hw_ctx
*hctx
;
956 queue_for_each_hw_ctx(q
, hctx
, i
)
957 blk_mq_start_hw_queue(hctx
);
959 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
961 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
963 struct blk_mq_hw_ctx
*hctx
;
966 queue_for_each_hw_ctx(q
, hctx
, i
) {
967 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
970 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
971 blk_mq_run_hw_queue(hctx
, async
);
974 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
976 static void blk_mq_run_work_fn(struct work_struct
*work
)
978 struct blk_mq_hw_ctx
*hctx
;
980 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
982 __blk_mq_run_hw_queue(hctx
);
985 static void blk_mq_delay_work_fn(struct work_struct
*work
)
987 struct blk_mq_hw_ctx
*hctx
;
989 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
991 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
992 __blk_mq_run_hw_queue(hctx
);
995 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
997 if (unlikely(!blk_mq_hw_queue_mapped(hctx
)))
1000 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
1001 &hctx
->delay_work
, msecs_to_jiffies(msecs
));
1003 EXPORT_SYMBOL(blk_mq_delay_queue
);
1005 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
1006 struct request
*rq
, bool at_head
)
1008 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1010 trace_block_rq_insert(hctx
->queue
, rq
);
1013 list_add(&rq
->queuelist
, &ctx
->rq_list
);
1015 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
1017 blk_mq_hctx_mark_pending(hctx
, ctx
);
1020 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
1023 struct request_queue
*q
= rq
->q
;
1024 struct blk_mq_hw_ctx
*hctx
;
1025 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
1027 current_ctx
= blk_mq_get_ctx(q
);
1028 if (!cpu_online(ctx
->cpu
))
1029 rq
->mq_ctx
= ctx
= current_ctx
;
1031 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1033 spin_lock(&ctx
->lock
);
1034 __blk_mq_insert_request(hctx
, rq
, at_head
);
1035 spin_unlock(&ctx
->lock
);
1038 blk_mq_run_hw_queue(hctx
, async
);
1040 blk_mq_put_ctx(current_ctx
);
1043 static void blk_mq_insert_requests(struct request_queue
*q
,
1044 struct blk_mq_ctx
*ctx
,
1045 struct list_head
*list
,
1050 struct blk_mq_hw_ctx
*hctx
;
1051 struct blk_mq_ctx
*current_ctx
;
1053 trace_block_unplug(q
, depth
, !from_schedule
);
1055 current_ctx
= blk_mq_get_ctx(q
);
1057 if (!cpu_online(ctx
->cpu
))
1059 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1062 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1065 spin_lock(&ctx
->lock
);
1066 while (!list_empty(list
)) {
1069 rq
= list_first_entry(list
, struct request
, queuelist
);
1070 list_del_init(&rq
->queuelist
);
1072 __blk_mq_insert_request(hctx
, rq
, false);
1074 spin_unlock(&ctx
->lock
);
1076 blk_mq_run_hw_queue(hctx
, from_schedule
);
1077 blk_mq_put_ctx(current_ctx
);
1080 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1082 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1083 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1085 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1086 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1087 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1090 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1092 struct blk_mq_ctx
*this_ctx
;
1093 struct request_queue
*this_q
;
1096 LIST_HEAD(ctx_list
);
1099 list_splice_init(&plug
->mq_list
, &list
);
1101 list_sort(NULL
, &list
, plug_ctx_cmp
);
1107 while (!list_empty(&list
)) {
1108 rq
= list_entry_rq(list
.next
);
1109 list_del_init(&rq
->queuelist
);
1111 if (rq
->mq_ctx
!= this_ctx
) {
1113 blk_mq_insert_requests(this_q
, this_ctx
,
1118 this_ctx
= rq
->mq_ctx
;
1124 list_add_tail(&rq
->queuelist
, &ctx_list
);
1128 * If 'this_ctx' is set, we know we have entries to complete
1129 * on 'ctx_list'. Do those.
1132 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1137 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1139 init_request_from_bio(rq
, bio
);
1141 if (blk_do_io_stat(rq
))
1142 blk_account_io_start(rq
, 1);
1145 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1147 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1148 !blk_queue_nomerges(hctx
->queue
);
1151 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1152 struct blk_mq_ctx
*ctx
,
1153 struct request
*rq
, struct bio
*bio
)
1155 if (!hctx_allow_merges(hctx
)) {
1156 blk_mq_bio_to_request(rq
, bio
);
1157 spin_lock(&ctx
->lock
);
1159 __blk_mq_insert_request(hctx
, rq
, false);
1160 spin_unlock(&ctx
->lock
);
1163 struct request_queue
*q
= hctx
->queue
;
1165 spin_lock(&ctx
->lock
);
1166 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1167 blk_mq_bio_to_request(rq
, bio
);
1171 spin_unlock(&ctx
->lock
);
1172 __blk_mq_free_request(hctx
, ctx
, rq
);
1177 struct blk_map_ctx
{
1178 struct blk_mq_hw_ctx
*hctx
;
1179 struct blk_mq_ctx
*ctx
;
1182 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1184 struct blk_map_ctx
*data
)
1186 struct blk_mq_hw_ctx
*hctx
;
1187 struct blk_mq_ctx
*ctx
;
1189 int rw
= bio_data_dir(bio
);
1190 struct blk_mq_alloc_data alloc_data
;
1192 if (unlikely(blk_mq_queue_enter(q
, GFP_KERNEL
))) {
1193 bio_endio(bio
, -EIO
);
1197 ctx
= blk_mq_get_ctx(q
);
1198 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1200 if (rw_is_sync(bio
->bi_rw
))
1203 trace_block_getrq(q
, bio
, rw
);
1204 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1206 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1207 if (unlikely(!rq
)) {
1208 __blk_mq_run_hw_queue(hctx
);
1209 blk_mq_put_ctx(ctx
);
1210 trace_block_sleeprq(q
, bio
, rw
);
1212 ctx
= blk_mq_get_ctx(q
);
1213 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1214 blk_mq_set_alloc_data(&alloc_data
, q
,
1215 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1216 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1217 ctx
= alloc_data
.ctx
;
1218 hctx
= alloc_data
.hctx
;
1227 static int blk_mq_direct_issue_request(struct request
*rq
)
1230 struct request_queue
*q
= rq
->q
;
1231 struct blk_mq_hw_ctx
*hctx
= q
->mq_ops
->map_queue(q
,
1233 struct blk_mq_queue_data bd
= {
1240 * For OK queue, we are done. For error, kill it. Any other
1241 * error (busy), just add it to our list as we previously
1244 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1245 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1248 __blk_mq_requeue_request(rq
);
1250 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1252 blk_mq_end_request(rq
, rq
->errors
);
1260 * Multiple hardware queue variant. This will not use per-process plugs,
1261 * but will attempt to bypass the hctx queueing if we can go straight to
1262 * hardware for SYNC IO.
1264 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1266 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1267 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1268 struct blk_map_ctx data
;
1270 unsigned int request_count
= 0;
1271 struct blk_plug
*plug
;
1273 blk_queue_bounce(q
, &bio
);
1275 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1276 bio_endio(bio
, -EIO
);
1280 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
1281 blk_attempt_plug_merge(q
, bio
, &request_count
))
1284 rq
= blk_mq_map_request(q
, bio
, &data
);
1288 if (unlikely(is_flush_fua
)) {
1289 blk_mq_bio_to_request(rq
, bio
);
1290 blk_insert_flush(rq
);
1294 plug
= current
->plug
;
1296 * If the driver supports defer issued based on 'last', then
1297 * queue it up like normal since we can potentially save some
1300 if (((plug
&& !blk_queue_nomerges(q
)) || is_sync
) &&
1301 !(data
.hctx
->flags
& BLK_MQ_F_DEFER_ISSUE
)) {
1302 struct request
*old_rq
= NULL
;
1304 blk_mq_bio_to_request(rq
, bio
);
1307 * we do limited pluging. If bio can be merged, do merge.
1308 * Otherwise the existing request in the plug list will be
1309 * issued. So the plug list will have one request at most
1312 if (!list_empty(&plug
->mq_list
)) {
1313 old_rq
= list_first_entry(&plug
->mq_list
,
1314 struct request
, queuelist
);
1315 list_del_init(&old_rq
->queuelist
);
1317 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1318 } else /* is_sync */
1320 blk_mq_put_ctx(data
.ctx
);
1323 if (!blk_mq_direct_issue_request(old_rq
))
1325 blk_mq_insert_request(old_rq
, false, true, true);
1329 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1331 * For a SYNC request, send it to the hardware immediately. For
1332 * an ASYNC request, just ensure that we run it later on. The
1333 * latter allows for merging opportunities and more efficient
1337 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1339 blk_mq_put_ctx(data
.ctx
);
1343 * Single hardware queue variant. This will attempt to use any per-process
1344 * plug for merging and IO deferral.
1346 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1348 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1349 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1350 struct blk_plug
*plug
;
1351 unsigned int request_count
= 0;
1352 struct blk_map_ctx data
;
1355 blk_queue_bounce(q
, &bio
);
1357 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1358 bio_endio(bio
, -EIO
);
1362 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
1363 blk_attempt_plug_merge(q
, bio
, &request_count
))
1366 rq
= blk_mq_map_request(q
, bio
, &data
);
1370 if (unlikely(is_flush_fua
)) {
1371 blk_mq_bio_to_request(rq
, bio
);
1372 blk_insert_flush(rq
);
1377 * A task plug currently exists. Since this is completely lockless,
1378 * utilize that to temporarily store requests until the task is
1379 * either done or scheduled away.
1381 plug
= current
->plug
;
1383 blk_mq_bio_to_request(rq
, bio
);
1384 if (list_empty(&plug
->mq_list
))
1385 trace_block_plug(q
);
1386 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1387 blk_flush_plug_list(plug
, false);
1388 trace_block_plug(q
);
1390 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1391 blk_mq_put_ctx(data
.ctx
);
1395 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1397 * For a SYNC request, send it to the hardware immediately. For
1398 * an ASYNC request, just ensure that we run it later on. The
1399 * latter allows for merging opportunities and more efficient
1403 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1406 blk_mq_put_ctx(data
.ctx
);
1410 * Default mapping to a software queue, since we use one per CPU.
1412 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1414 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1416 EXPORT_SYMBOL(blk_mq_map_queue
);
1418 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1419 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1423 if (tags
->rqs
&& set
->ops
->exit_request
) {
1426 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1429 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1431 tags
->rqs
[i
] = NULL
;
1435 while (!list_empty(&tags
->page_list
)) {
1436 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1437 list_del_init(&page
->lru
);
1438 __free_pages(page
, page
->private);
1443 blk_mq_free_tags(tags
);
1446 static size_t order_to_size(unsigned int order
)
1448 return (size_t)PAGE_SIZE
<< order
;
1451 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1452 unsigned int hctx_idx
)
1454 struct blk_mq_tags
*tags
;
1455 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1456 size_t rq_size
, left
;
1458 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1460 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
1464 INIT_LIST_HEAD(&tags
->page_list
);
1466 tags
->rqs
= kzalloc_node(set
->queue_depth
* sizeof(struct request
*),
1467 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1470 blk_mq_free_tags(tags
);
1475 * rq_size is the size of the request plus driver payload, rounded
1476 * to the cacheline size
1478 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1480 left
= rq_size
* set
->queue_depth
;
1482 for (i
= 0; i
< set
->queue_depth
; ) {
1483 int this_order
= max_order
;
1488 while (left
< order_to_size(this_order
- 1) && this_order
)
1492 page
= alloc_pages_node(set
->numa_node
,
1493 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
1499 if (order_to_size(this_order
) < rq_size
)
1506 page
->private = this_order
;
1507 list_add_tail(&page
->lru
, &tags
->page_list
);
1509 p
= page_address(page
);
1510 entries_per_page
= order_to_size(this_order
) / rq_size
;
1511 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1512 left
-= to_do
* rq_size
;
1513 for (j
= 0; j
< to_do
; j
++) {
1515 if (set
->ops
->init_request
) {
1516 if (set
->ops
->init_request(set
->driver_data
,
1517 tags
->rqs
[i
], hctx_idx
, i
,
1519 tags
->rqs
[i
] = NULL
;
1532 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1536 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1541 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1543 unsigned int bpw
= 8, total
, num_maps
, i
;
1545 bitmap
->bits_per_word
= bpw
;
1547 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1548 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1554 for (i
= 0; i
< num_maps
; i
++) {
1555 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1556 total
-= bitmap
->map
[i
].depth
;
1562 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1564 struct request_queue
*q
= hctx
->queue
;
1565 struct blk_mq_ctx
*ctx
;
1569 * Move ctx entries to new CPU, if this one is going away.
1571 ctx
= __blk_mq_get_ctx(q
, cpu
);
1573 spin_lock(&ctx
->lock
);
1574 if (!list_empty(&ctx
->rq_list
)) {
1575 list_splice_init(&ctx
->rq_list
, &tmp
);
1576 blk_mq_hctx_clear_pending(hctx
, ctx
);
1578 spin_unlock(&ctx
->lock
);
1580 if (list_empty(&tmp
))
1583 ctx
= blk_mq_get_ctx(q
);
1584 spin_lock(&ctx
->lock
);
1586 while (!list_empty(&tmp
)) {
1589 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1591 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1594 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1595 blk_mq_hctx_mark_pending(hctx
, ctx
);
1597 spin_unlock(&ctx
->lock
);
1599 blk_mq_run_hw_queue(hctx
, true);
1600 blk_mq_put_ctx(ctx
);
1604 static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1606 struct request_queue
*q
= hctx
->queue
;
1607 struct blk_mq_tag_set
*set
= q
->tag_set
;
1609 if (set
->tags
[hctx
->queue_num
])
1612 set
->tags
[hctx
->queue_num
] = blk_mq_init_rq_map(set
, hctx
->queue_num
);
1613 if (!set
->tags
[hctx
->queue_num
])
1616 hctx
->tags
= set
->tags
[hctx
->queue_num
];
1620 static int blk_mq_hctx_notify(void *data
, unsigned long action
,
1623 struct blk_mq_hw_ctx
*hctx
= data
;
1625 if (action
== CPU_DEAD
|| action
== CPU_DEAD_FROZEN
)
1626 return blk_mq_hctx_cpu_offline(hctx
, cpu
);
1627 else if (action
== CPU_ONLINE
|| action
== CPU_ONLINE_FROZEN
)
1628 return blk_mq_hctx_cpu_online(hctx
, cpu
);
1633 static void blk_mq_exit_hctx(struct request_queue
*q
,
1634 struct blk_mq_tag_set
*set
,
1635 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1637 unsigned flush_start_tag
= set
->queue_depth
;
1639 blk_mq_tag_idle(hctx
);
1641 if (set
->ops
->exit_request
)
1642 set
->ops
->exit_request(set
->driver_data
,
1643 hctx
->fq
->flush_rq
, hctx_idx
,
1644 flush_start_tag
+ hctx_idx
);
1646 if (set
->ops
->exit_hctx
)
1647 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1649 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1650 blk_free_flush_queue(hctx
->fq
);
1652 blk_mq_free_bitmap(&hctx
->ctx_map
);
1655 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1656 struct blk_mq_tag_set
*set
, int nr_queue
)
1658 struct blk_mq_hw_ctx
*hctx
;
1661 queue_for_each_hw_ctx(q
, hctx
, i
) {
1664 blk_mq_exit_hctx(q
, set
, hctx
, i
);
1668 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1669 struct blk_mq_tag_set
*set
)
1671 struct blk_mq_hw_ctx
*hctx
;
1674 queue_for_each_hw_ctx(q
, hctx
, i
)
1675 free_cpumask_var(hctx
->cpumask
);
1678 static int blk_mq_init_hctx(struct request_queue
*q
,
1679 struct blk_mq_tag_set
*set
,
1680 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
1683 unsigned flush_start_tag
= set
->queue_depth
;
1685 node
= hctx
->numa_node
;
1686 if (node
== NUMA_NO_NODE
)
1687 node
= hctx
->numa_node
= set
->numa_node
;
1689 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1690 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1691 spin_lock_init(&hctx
->lock
);
1692 INIT_LIST_HEAD(&hctx
->dispatch
);
1694 hctx
->queue_num
= hctx_idx
;
1695 hctx
->flags
= set
->flags
;
1697 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1698 blk_mq_hctx_notify
, hctx
);
1699 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1701 hctx
->tags
= set
->tags
[hctx_idx
];
1704 * Allocate space for all possible cpus to avoid allocation at
1707 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1710 goto unregister_cpu_notifier
;
1712 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1717 if (set
->ops
->init_hctx
&&
1718 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
1721 hctx
->fq
= blk_alloc_flush_queue(q
, hctx
->numa_node
, set
->cmd_size
);
1725 if (set
->ops
->init_request
&&
1726 set
->ops
->init_request(set
->driver_data
,
1727 hctx
->fq
->flush_rq
, hctx_idx
,
1728 flush_start_tag
+ hctx_idx
, node
))
1736 if (set
->ops
->exit_hctx
)
1737 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1739 blk_mq_free_bitmap(&hctx
->ctx_map
);
1742 unregister_cpu_notifier
:
1743 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1748 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1749 struct blk_mq_tag_set
*set
)
1751 struct blk_mq_hw_ctx
*hctx
;
1755 * Initialize hardware queues
1757 queue_for_each_hw_ctx(q
, hctx
, i
) {
1758 if (blk_mq_init_hctx(q
, set
, hctx
, i
))
1762 if (i
== q
->nr_hw_queues
)
1768 blk_mq_exit_hw_queues(q
, set
, i
);
1773 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1774 unsigned int nr_hw_queues
)
1778 for_each_possible_cpu(i
) {
1779 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1780 struct blk_mq_hw_ctx
*hctx
;
1782 memset(__ctx
, 0, sizeof(*__ctx
));
1784 spin_lock_init(&__ctx
->lock
);
1785 INIT_LIST_HEAD(&__ctx
->rq_list
);
1788 /* If the cpu isn't online, the cpu is mapped to first hctx */
1792 hctx
= q
->mq_ops
->map_queue(q
, i
);
1795 * Set local node, IFF we have more than one hw queue. If
1796 * not, we remain on the home node of the device
1798 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1799 hctx
->numa_node
= cpu_to_node(i
);
1803 static void blk_mq_map_swqueue(struct request_queue
*q
)
1806 struct blk_mq_hw_ctx
*hctx
;
1807 struct blk_mq_ctx
*ctx
;
1809 queue_for_each_hw_ctx(q
, hctx
, i
) {
1810 cpumask_clear(hctx
->cpumask
);
1815 * Map software to hardware queues
1817 queue_for_each_ctx(q
, ctx
, i
) {
1818 /* If the cpu isn't online, the cpu is mapped to first hctx */
1822 hctx
= q
->mq_ops
->map_queue(q
, i
);
1823 cpumask_set_cpu(i
, hctx
->cpumask
);
1824 ctx
->index_hw
= hctx
->nr_ctx
;
1825 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1828 queue_for_each_hw_ctx(q
, hctx
, i
) {
1829 struct blk_mq_ctxmap
*map
= &hctx
->ctx_map
;
1832 * If no software queues are mapped to this hardware queue,
1833 * disable it and free the request entries.
1835 if (!hctx
->nr_ctx
) {
1836 struct blk_mq_tag_set
*set
= q
->tag_set
;
1839 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1840 set
->tags
[i
] = NULL
;
1847 * Set the map size to the number of mapped software queues.
1848 * This is more accurate and more efficient than looping
1849 * over all possibly mapped software queues.
1851 map
->size
= DIV_ROUND_UP(hctx
->nr_ctx
, map
->bits_per_word
);
1854 * Initialize batch roundrobin counts
1856 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1857 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1861 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1863 struct blk_mq_hw_ctx
*hctx
;
1864 struct request_queue
*q
;
1868 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1873 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1874 blk_mq_freeze_queue(q
);
1876 queue_for_each_hw_ctx(q
, hctx
, i
) {
1878 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1880 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1882 blk_mq_unfreeze_queue(q
);
1886 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1888 struct blk_mq_tag_set
*set
= q
->tag_set
;
1890 mutex_lock(&set
->tag_list_lock
);
1891 list_del_init(&q
->tag_set_list
);
1892 blk_mq_update_tag_set_depth(set
);
1893 mutex_unlock(&set
->tag_list_lock
);
1896 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1897 struct request_queue
*q
)
1901 mutex_lock(&set
->tag_list_lock
);
1902 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1903 blk_mq_update_tag_set_depth(set
);
1904 mutex_unlock(&set
->tag_list_lock
);
1908 * It is the actual release handler for mq, but we do it from
1909 * request queue's release handler for avoiding use-after-free
1910 * and headache because q->mq_kobj shouldn't have been introduced,
1911 * but we can't group ctx/kctx kobj without it.
1913 void blk_mq_release(struct request_queue
*q
)
1915 struct blk_mq_hw_ctx
*hctx
;
1918 /* hctx kobj stays in hctx */
1919 queue_for_each_hw_ctx(q
, hctx
, i
)
1922 kfree(q
->queue_hw_ctx
);
1924 /* ctx kobj stays in queue_ctx */
1925 free_percpu(q
->queue_ctx
);
1928 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1930 struct request_queue
*uninit_q
, *q
;
1932 uninit_q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1934 return ERR_PTR(-ENOMEM
);
1936 q
= blk_mq_init_allocated_queue(set
, uninit_q
);
1938 blk_cleanup_queue(uninit_q
);
1942 EXPORT_SYMBOL(blk_mq_init_queue
);
1944 struct request_queue
*blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
1945 struct request_queue
*q
)
1947 struct blk_mq_hw_ctx
**hctxs
;
1948 struct blk_mq_ctx __percpu
*ctx
;
1952 ctx
= alloc_percpu(struct blk_mq_ctx
);
1954 return ERR_PTR(-ENOMEM
);
1956 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1962 map
= blk_mq_make_queue_map(set
);
1966 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1967 int node
= blk_mq_hw_queue_to_node(map
, i
);
1969 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1974 if (!zalloc_cpumask_var_node(&hctxs
[i
]->cpumask
, GFP_KERNEL
,
1978 atomic_set(&hctxs
[i
]->nr_active
, 0);
1979 hctxs
[i
]->numa_node
= node
;
1980 hctxs
[i
]->queue_num
= i
;
1984 * Init percpu_ref in atomic mode so that it's faster to shutdown.
1985 * See blk_register_queue() for details.
1987 if (percpu_ref_init(&q
->mq_usage_counter
, blk_mq_usage_counter_release
,
1988 PERCPU_REF_INIT_ATOMIC
, GFP_KERNEL
))
1991 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
1992 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30000);
1994 q
->nr_queues
= nr_cpu_ids
;
1995 q
->nr_hw_queues
= set
->nr_hw_queues
;
1999 q
->queue_hw_ctx
= hctxs
;
2001 q
->mq_ops
= set
->ops
;
2002 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
2004 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
2005 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
2007 q
->sg_reserved_size
= INT_MAX
;
2009 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
2010 INIT_LIST_HEAD(&q
->requeue_list
);
2011 spin_lock_init(&q
->requeue_lock
);
2013 if (q
->nr_hw_queues
> 1)
2014 blk_queue_make_request(q
, blk_mq_make_request
);
2016 blk_queue_make_request(q
, blk_sq_make_request
);
2019 * Do this after blk_queue_make_request() overrides it...
2021 q
->nr_requests
= set
->queue_depth
;
2023 if (set
->ops
->complete
)
2024 blk_queue_softirq_done(q
, set
->ops
->complete
);
2026 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
2028 if (blk_mq_init_hw_queues(q
, set
))
2031 mutex_lock(&all_q_mutex
);
2032 list_add_tail(&q
->all_q_node
, &all_q_list
);
2033 mutex_unlock(&all_q_mutex
);
2035 blk_mq_add_queue_tag_set(set
, q
);
2037 blk_mq_map_swqueue(q
);
2043 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2046 free_cpumask_var(hctxs
[i
]->cpumask
);
2053 return ERR_PTR(-ENOMEM
);
2055 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
2057 void blk_mq_free_queue(struct request_queue
*q
)
2059 struct blk_mq_tag_set
*set
= q
->tag_set
;
2061 blk_mq_del_queue_tag_set(q
);
2063 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
2064 blk_mq_free_hw_queues(q
, set
);
2066 percpu_ref_exit(&q
->mq_usage_counter
);
2072 mutex_lock(&all_q_mutex
);
2073 list_del_init(&q
->all_q_node
);
2074 mutex_unlock(&all_q_mutex
);
2077 /* Basically redo blk_mq_init_queue with queue frozen */
2078 static void blk_mq_queue_reinit(struct request_queue
*q
)
2080 WARN_ON_ONCE(!q
->mq_freeze_depth
);
2082 blk_mq_sysfs_unregister(q
);
2084 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
2087 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
2088 * we should change hctx numa_node according to new topology (this
2089 * involves free and re-allocate memory, worthy doing?)
2092 blk_mq_map_swqueue(q
);
2094 blk_mq_sysfs_register(q
);
2097 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
2098 unsigned long action
, void *hcpu
)
2100 struct request_queue
*q
;
2103 * Before new mappings are established, hotadded cpu might already
2104 * start handling requests. This doesn't break anything as we map
2105 * offline CPUs to first hardware queue. We will re-init the queue
2106 * below to get optimal settings.
2108 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
2109 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
2112 mutex_lock(&all_q_mutex
);
2115 * We need to freeze and reinit all existing queues. Freezing
2116 * involves synchronous wait for an RCU grace period and doing it
2117 * one by one may take a long time. Start freezing all queues in
2118 * one swoop and then wait for the completions so that freezing can
2119 * take place in parallel.
2121 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2122 blk_mq_freeze_queue_start(q
);
2123 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2124 blk_mq_freeze_queue_wait(q
);
2126 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2127 blk_mq_queue_reinit(q
);
2129 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2130 blk_mq_unfreeze_queue(q
);
2132 mutex_unlock(&all_q_mutex
);
2136 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2140 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2141 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
2150 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2156 * Allocate the request maps associated with this tag_set. Note that this
2157 * may reduce the depth asked for, if memory is tight. set->queue_depth
2158 * will be updated to reflect the allocated depth.
2160 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2165 depth
= set
->queue_depth
;
2167 err
= __blk_mq_alloc_rq_maps(set
);
2171 set
->queue_depth
>>= 1;
2172 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
2176 } while (set
->queue_depth
);
2178 if (!set
->queue_depth
|| err
) {
2179 pr_err("blk-mq: failed to allocate request map\n");
2183 if (depth
!= set
->queue_depth
)
2184 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2185 depth
, set
->queue_depth
);
2191 * Alloc a tag set to be associated with one or more request queues.
2192 * May fail with EINVAL for various error conditions. May adjust the
2193 * requested depth down, if if it too large. In that case, the set
2194 * value will be stored in set->queue_depth.
2196 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2198 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
2200 if (!set
->nr_hw_queues
)
2202 if (!set
->queue_depth
)
2204 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2207 if (!set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
2210 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2211 pr_info("blk-mq: reduced tag depth to %u\n",
2213 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2217 * If a crashdump is active, then we are potentially in a very
2218 * memory constrained environment. Limit us to 1 queue and
2219 * 64 tags to prevent using too much memory.
2221 if (is_kdump_kernel()) {
2222 set
->nr_hw_queues
= 1;
2223 set
->queue_depth
= min(64U, set
->queue_depth
);
2226 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
2227 sizeof(struct blk_mq_tags
*),
2228 GFP_KERNEL
, set
->numa_node
);
2232 if (blk_mq_alloc_rq_maps(set
))
2235 mutex_init(&set
->tag_list_lock
);
2236 INIT_LIST_HEAD(&set
->tag_list
);
2244 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2246 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2250 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2252 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2258 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2260 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2262 struct blk_mq_tag_set
*set
= q
->tag_set
;
2263 struct blk_mq_hw_ctx
*hctx
;
2266 if (!set
|| nr
> set
->queue_depth
)
2270 queue_for_each_hw_ctx(q
, hctx
, i
) {
2271 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2277 q
->nr_requests
= nr
;
2282 void blk_mq_disable_hotplug(void)
2284 mutex_lock(&all_q_mutex
);
2287 void blk_mq_enable_hotplug(void)
2289 mutex_unlock(&all_q_mutex
);
2292 static int __init
blk_mq_init(void)
2296 hotcpu_notifier(blk_mq_queue_reinit_notify
, 0);
2300 subsys_initcall(blk_mq_init
);