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 !atomic_read(&q
->mq_freeze_depth
) ||
94 if (blk_queue_dying(q
))
101 static void blk_mq_queue_exit(struct request_queue
*q
)
103 percpu_ref_put(&q
->mq_usage_counter
);
106 static void blk_mq_usage_counter_release(struct percpu_ref
*ref
)
108 struct request_queue
*q
=
109 container_of(ref
, struct request_queue
, mq_usage_counter
);
111 wake_up_all(&q
->mq_freeze_wq
);
114 void blk_mq_freeze_queue_start(struct request_queue
*q
)
118 freeze_depth
= atomic_inc_return(&q
->mq_freeze_depth
);
119 if (freeze_depth
== 1) {
120 percpu_ref_kill(&q
->mq_usage_counter
);
121 blk_mq_run_hw_queues(q
, false);
124 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start
);
126 static void blk_mq_freeze_queue_wait(struct request_queue
*q
)
128 wait_event(q
->mq_freeze_wq
, percpu_ref_is_zero(&q
->mq_usage_counter
));
132 * Guarantee no request is in use, so we can change any data structure of
133 * the queue afterward.
135 void blk_mq_freeze_queue(struct request_queue
*q
)
137 blk_mq_freeze_queue_start(q
);
138 blk_mq_freeze_queue_wait(q
);
140 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue
);
142 void blk_mq_unfreeze_queue(struct request_queue
*q
)
146 freeze_depth
= atomic_dec_return(&q
->mq_freeze_depth
);
147 WARN_ON_ONCE(freeze_depth
< 0);
149 percpu_ref_reinit(&q
->mq_usage_counter
);
150 wake_up_all(&q
->mq_freeze_wq
);
153 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue
);
155 void blk_mq_wake_waiters(struct request_queue
*q
)
157 struct blk_mq_hw_ctx
*hctx
;
160 queue_for_each_hw_ctx(q
, hctx
, i
)
161 if (blk_mq_hw_queue_mapped(hctx
))
162 blk_mq_tag_wakeup_all(hctx
->tags
, true);
165 * If we are called because the queue has now been marked as
166 * dying, we need to ensure that processes currently waiting on
167 * the queue are notified as well.
169 wake_up_all(&q
->mq_freeze_wq
);
172 bool blk_mq_can_queue(struct blk_mq_hw_ctx
*hctx
)
174 return blk_mq_has_free_tags(hctx
->tags
);
176 EXPORT_SYMBOL(blk_mq_can_queue
);
178 static void blk_mq_rq_ctx_init(struct request_queue
*q
, struct blk_mq_ctx
*ctx
,
179 struct request
*rq
, unsigned int rw_flags
)
181 if (blk_queue_io_stat(q
))
182 rw_flags
|= REQ_IO_STAT
;
184 INIT_LIST_HEAD(&rq
->queuelist
);
185 /* csd/requeue_work/fifo_time is initialized before use */
188 rq
->cmd_flags
|= rw_flags
;
189 /* do not touch atomic flags, it needs atomic ops against the timer */
191 INIT_HLIST_NODE(&rq
->hash
);
192 RB_CLEAR_NODE(&rq
->rb_node
);
195 rq
->start_time
= jiffies
;
196 #ifdef CONFIG_BLK_CGROUP
198 set_start_time_ns(rq
);
199 rq
->io_start_time_ns
= 0;
201 rq
->nr_phys_segments
= 0;
202 #if defined(CONFIG_BLK_DEV_INTEGRITY)
203 rq
->nr_integrity_segments
= 0;
206 /* tag was already set */
216 INIT_LIST_HEAD(&rq
->timeout_list
);
220 rq
->end_io_data
= NULL
;
223 ctx
->rq_dispatched
[rw_is_sync(rw_flags
)]++;
226 static struct request
*
227 __blk_mq_alloc_request(struct blk_mq_alloc_data
*data
, int rw
)
232 tag
= blk_mq_get_tag(data
);
233 if (tag
!= BLK_MQ_TAG_FAIL
) {
234 rq
= data
->hctx
->tags
->rqs
[tag
];
236 if (blk_mq_tag_busy(data
->hctx
)) {
237 rq
->cmd_flags
= REQ_MQ_INFLIGHT
;
238 atomic_inc(&data
->hctx
->nr_active
);
242 blk_mq_rq_ctx_init(data
->q
, data
->ctx
, rq
, rw
);
249 struct request
*blk_mq_alloc_request(struct request_queue
*q
, int rw
, gfp_t gfp
,
252 struct blk_mq_ctx
*ctx
;
253 struct blk_mq_hw_ctx
*hctx
;
255 struct blk_mq_alloc_data alloc_data
;
258 ret
= blk_mq_queue_enter(q
, gfp
);
262 ctx
= blk_mq_get_ctx(q
);
263 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
264 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
& ~__GFP_WAIT
,
265 reserved
, ctx
, hctx
);
267 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
268 if (!rq
&& (gfp
& __GFP_WAIT
)) {
269 __blk_mq_run_hw_queue(hctx
);
272 ctx
= blk_mq_get_ctx(q
);
273 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
274 blk_mq_set_alloc_data(&alloc_data
, q
, gfp
, reserved
, ctx
,
276 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
277 ctx
= alloc_data
.ctx
;
281 blk_mq_queue_exit(q
);
282 return ERR_PTR(-EWOULDBLOCK
);
286 EXPORT_SYMBOL(blk_mq_alloc_request
);
288 static void __blk_mq_free_request(struct blk_mq_hw_ctx
*hctx
,
289 struct blk_mq_ctx
*ctx
, struct request
*rq
)
291 const int tag
= rq
->tag
;
292 struct request_queue
*q
= rq
->q
;
294 if (rq
->cmd_flags
& REQ_MQ_INFLIGHT
)
295 atomic_dec(&hctx
->nr_active
);
298 clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
299 blk_mq_put_tag(hctx
, tag
, &ctx
->last_tag
);
300 blk_mq_queue_exit(q
);
303 void blk_mq_free_hctx_request(struct blk_mq_hw_ctx
*hctx
, struct request
*rq
)
305 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
307 ctx
->rq_completed
[rq_is_sync(rq
)]++;
308 __blk_mq_free_request(hctx
, ctx
, rq
);
311 EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request
);
313 void blk_mq_free_request(struct request
*rq
)
315 struct blk_mq_hw_ctx
*hctx
;
316 struct request_queue
*q
= rq
->q
;
318 hctx
= q
->mq_ops
->map_queue(q
, rq
->mq_ctx
->cpu
);
319 blk_mq_free_hctx_request(hctx
, rq
);
321 EXPORT_SYMBOL_GPL(blk_mq_free_request
);
323 inline void __blk_mq_end_request(struct request
*rq
, int error
)
325 blk_account_io_done(rq
);
328 rq
->end_io(rq
, error
);
330 if (unlikely(blk_bidi_rq(rq
)))
331 blk_mq_free_request(rq
->next_rq
);
332 blk_mq_free_request(rq
);
335 EXPORT_SYMBOL(__blk_mq_end_request
);
337 void blk_mq_end_request(struct request
*rq
, int error
)
339 if (blk_update_request(rq
, error
, blk_rq_bytes(rq
)))
341 __blk_mq_end_request(rq
, error
);
343 EXPORT_SYMBOL(blk_mq_end_request
);
345 static void __blk_mq_complete_request_remote(void *data
)
347 struct request
*rq
= data
;
349 rq
->q
->softirq_done_fn(rq
);
352 static void blk_mq_ipi_complete_request(struct request
*rq
)
354 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
358 if (!test_bit(QUEUE_FLAG_SAME_COMP
, &rq
->q
->queue_flags
)) {
359 rq
->q
->softirq_done_fn(rq
);
364 if (!test_bit(QUEUE_FLAG_SAME_FORCE
, &rq
->q
->queue_flags
))
365 shared
= cpus_share_cache(cpu
, ctx
->cpu
);
367 if (cpu
!= ctx
->cpu
&& !shared
&& cpu_online(ctx
->cpu
)) {
368 rq
->csd
.func
= __blk_mq_complete_request_remote
;
371 smp_call_function_single_async(ctx
->cpu
, &rq
->csd
);
373 rq
->q
->softirq_done_fn(rq
);
378 void __blk_mq_complete_request(struct request
*rq
)
380 struct request_queue
*q
= rq
->q
;
382 if (!q
->softirq_done_fn
)
383 blk_mq_end_request(rq
, rq
->errors
);
385 blk_mq_ipi_complete_request(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 __blk_mq_complete_request(rq
);
405 EXPORT_SYMBOL(blk_mq_complete_request
);
407 int blk_mq_request_started(struct request
*rq
)
409 return test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
411 EXPORT_SYMBOL_GPL(blk_mq_request_started
);
413 void blk_mq_start_request(struct request
*rq
)
415 struct request_queue
*q
= rq
->q
;
417 trace_block_rq_issue(q
, rq
);
419 rq
->resid_len
= blk_rq_bytes(rq
);
420 if (unlikely(blk_bidi_rq(rq
)))
421 rq
->next_rq
->resid_len
= blk_rq_bytes(rq
->next_rq
);
426 * Ensure that ->deadline is visible before set the started
427 * flag and clear the completed flag.
429 smp_mb__before_atomic();
432 * Mark us as started and clear complete. Complete might have been
433 * set if requeue raced with timeout, which then marked it as
434 * complete. So be sure to clear complete again when we start
435 * the request, otherwise we'll ignore the completion event.
437 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
))
438 set_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
);
439 if (test_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
))
440 clear_bit(REQ_ATOM_COMPLETE
, &rq
->atomic_flags
);
442 if (q
->dma_drain_size
&& blk_rq_bytes(rq
)) {
444 * Make sure space for the drain appears. We know we can do
445 * this because max_hw_segments has been adjusted to be one
446 * fewer than the device can handle.
448 rq
->nr_phys_segments
++;
451 EXPORT_SYMBOL(blk_mq_start_request
);
453 static void __blk_mq_requeue_request(struct request
*rq
)
455 struct request_queue
*q
= rq
->q
;
457 trace_block_rq_requeue(q
, rq
);
459 if (test_and_clear_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
460 if (q
->dma_drain_size
&& blk_rq_bytes(rq
))
461 rq
->nr_phys_segments
--;
465 void blk_mq_requeue_request(struct request
*rq
)
467 __blk_mq_requeue_request(rq
);
469 BUG_ON(blk_queued_rq(rq
));
470 blk_mq_add_to_requeue_list(rq
, true);
472 EXPORT_SYMBOL(blk_mq_requeue_request
);
474 static void blk_mq_requeue_work(struct work_struct
*work
)
476 struct request_queue
*q
=
477 container_of(work
, struct request_queue
, requeue_work
);
479 struct request
*rq
, *next
;
482 spin_lock_irqsave(&q
->requeue_lock
, flags
);
483 list_splice_init(&q
->requeue_list
, &rq_list
);
484 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
486 list_for_each_entry_safe(rq
, next
, &rq_list
, queuelist
) {
487 if (!(rq
->cmd_flags
& REQ_SOFTBARRIER
))
490 rq
->cmd_flags
&= ~REQ_SOFTBARRIER
;
491 list_del_init(&rq
->queuelist
);
492 blk_mq_insert_request(rq
, true, false, false);
495 while (!list_empty(&rq_list
)) {
496 rq
= list_entry(rq_list
.next
, struct request
, queuelist
);
497 list_del_init(&rq
->queuelist
);
498 blk_mq_insert_request(rq
, false, false, false);
502 * Use the start variant of queue running here, so that running
503 * the requeue work will kick stopped queues.
505 blk_mq_start_hw_queues(q
);
508 void blk_mq_add_to_requeue_list(struct request
*rq
, bool at_head
)
510 struct request_queue
*q
= rq
->q
;
514 * We abuse this flag that is otherwise used by the I/O scheduler to
515 * request head insertation from the workqueue.
517 BUG_ON(rq
->cmd_flags
& REQ_SOFTBARRIER
);
519 spin_lock_irqsave(&q
->requeue_lock
, flags
);
521 rq
->cmd_flags
|= REQ_SOFTBARRIER
;
522 list_add(&rq
->queuelist
, &q
->requeue_list
);
524 list_add_tail(&rq
->queuelist
, &q
->requeue_list
);
526 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
528 EXPORT_SYMBOL(blk_mq_add_to_requeue_list
);
530 void blk_mq_cancel_requeue_work(struct request_queue
*q
)
532 cancel_work_sync(&q
->requeue_work
);
534 EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work
);
536 void blk_mq_kick_requeue_list(struct request_queue
*q
)
538 kblockd_schedule_work(&q
->requeue_work
);
540 EXPORT_SYMBOL(blk_mq_kick_requeue_list
);
542 void blk_mq_abort_requeue_list(struct request_queue
*q
)
547 spin_lock_irqsave(&q
->requeue_lock
, flags
);
548 list_splice_init(&q
->requeue_list
, &rq_list
);
549 spin_unlock_irqrestore(&q
->requeue_lock
, flags
);
551 while (!list_empty(&rq_list
)) {
554 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
555 list_del_init(&rq
->queuelist
);
557 blk_mq_end_request(rq
, rq
->errors
);
560 EXPORT_SYMBOL(blk_mq_abort_requeue_list
);
562 static inline bool is_flush_request(struct request
*rq
,
563 struct blk_flush_queue
*fq
, unsigned int tag
)
565 return ((rq
->cmd_flags
& REQ_FLUSH_SEQ
) &&
566 fq
->flush_rq
->tag
== tag
);
569 struct request
*blk_mq_tag_to_rq(struct blk_mq_tags
*tags
, unsigned int tag
)
571 struct request
*rq
= tags
->rqs
[tag
];
572 /* mq_ctx of flush rq is always cloned from the corresponding req */
573 struct blk_flush_queue
*fq
= blk_get_flush_queue(rq
->q
, rq
->mq_ctx
);
575 if (!is_flush_request(rq
, fq
, tag
))
580 EXPORT_SYMBOL(blk_mq_tag_to_rq
);
582 struct blk_mq_timeout_data
{
584 unsigned int next_set
;
587 void blk_mq_rq_timed_out(struct request
*req
, bool reserved
)
589 struct blk_mq_ops
*ops
= req
->q
->mq_ops
;
590 enum blk_eh_timer_return ret
= BLK_EH_RESET_TIMER
;
593 * We know that complete is set at this point. If STARTED isn't set
594 * anymore, then the request isn't active and the "timeout" should
595 * just be ignored. This can happen due to the bitflag ordering.
596 * Timeout first checks if STARTED is set, and if it is, assumes
597 * the request is active. But if we race with completion, then
598 * we both flags will get cleared. So check here again, and ignore
599 * a timeout event with a request that isn't active.
601 if (!test_bit(REQ_ATOM_STARTED
, &req
->atomic_flags
))
605 ret
= ops
->timeout(req
, reserved
);
609 __blk_mq_complete_request(req
);
611 case BLK_EH_RESET_TIMER
:
613 blk_clear_rq_complete(req
);
615 case BLK_EH_NOT_HANDLED
:
618 printk(KERN_ERR
"block: bad eh return: %d\n", ret
);
623 static void blk_mq_check_expired(struct blk_mq_hw_ctx
*hctx
,
624 struct request
*rq
, void *priv
, bool reserved
)
626 struct blk_mq_timeout_data
*data
= priv
;
628 if (!test_bit(REQ_ATOM_STARTED
, &rq
->atomic_flags
)) {
630 * If a request wasn't started before the queue was
631 * marked dying, kill it here or it'll go unnoticed.
633 if (unlikely(blk_queue_dying(rq
->q
))) {
635 blk_mq_complete_request(rq
);
639 if (rq
->cmd_flags
& REQ_NO_TIMEOUT
)
642 if (time_after_eq(jiffies
, rq
->deadline
)) {
643 if (!blk_mark_rq_complete(rq
))
644 blk_mq_rq_timed_out(rq
, reserved
);
645 } else if (!data
->next_set
|| time_after(data
->next
, rq
->deadline
)) {
646 data
->next
= rq
->deadline
;
651 static void blk_mq_rq_timer(unsigned long priv
)
653 struct request_queue
*q
= (struct request_queue
*)priv
;
654 struct blk_mq_timeout_data data
= {
658 struct blk_mq_hw_ctx
*hctx
;
661 queue_for_each_hw_ctx(q
, hctx
, i
) {
663 * If not software queues are currently mapped to this
664 * hardware queue, there's nothing to check
666 if (!blk_mq_hw_queue_mapped(hctx
))
669 blk_mq_tag_busy_iter(hctx
, blk_mq_check_expired
, &data
);
673 data
.next
= blk_rq_timeout(round_jiffies_up(data
.next
));
674 mod_timer(&q
->timeout
, data
.next
);
676 queue_for_each_hw_ctx(q
, hctx
, i
) {
677 /* the hctx may be unmapped, so check it here */
678 if (blk_mq_hw_queue_mapped(hctx
))
679 blk_mq_tag_idle(hctx
);
685 * Reverse check our software queue for entries that we could potentially
686 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
687 * too much time checking for merges.
689 static bool blk_mq_attempt_merge(struct request_queue
*q
,
690 struct blk_mq_ctx
*ctx
, struct bio
*bio
)
695 list_for_each_entry_reverse(rq
, &ctx
->rq_list
, queuelist
) {
701 if (!blk_rq_merge_ok(rq
, bio
))
704 el_ret
= blk_try_merge(rq
, bio
);
705 if (el_ret
== ELEVATOR_BACK_MERGE
) {
706 if (bio_attempt_back_merge(q
, rq
, bio
)) {
711 } else if (el_ret
== ELEVATOR_FRONT_MERGE
) {
712 if (bio_attempt_front_merge(q
, rq
, bio
)) {
724 * Process software queues that have been marked busy, splicing them
725 * to the for-dispatch
727 static void flush_busy_ctxs(struct blk_mq_hw_ctx
*hctx
, struct list_head
*list
)
729 struct blk_mq_ctx
*ctx
;
732 for (i
= 0; i
< hctx
->ctx_map
.size
; i
++) {
733 struct blk_align_bitmap
*bm
= &hctx
->ctx_map
.map
[i
];
734 unsigned int off
, bit
;
740 off
= i
* hctx
->ctx_map
.bits_per_word
;
742 bit
= find_next_bit(&bm
->word
, bm
->depth
, bit
);
743 if (bit
>= bm
->depth
)
746 ctx
= hctx
->ctxs
[bit
+ off
];
747 clear_bit(bit
, &bm
->word
);
748 spin_lock(&ctx
->lock
);
749 list_splice_tail_init(&ctx
->rq_list
, list
);
750 spin_unlock(&ctx
->lock
);
758 * Run this hardware queue, pulling any software queues mapped to it in.
759 * Note that this function currently has various problems around ordering
760 * of IO. In particular, we'd like FIFO behaviour on handling existing
761 * items on the hctx->dispatch list. Ignore that for now.
763 static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
)
765 struct request_queue
*q
= hctx
->queue
;
768 LIST_HEAD(driver_list
);
769 struct list_head
*dptr
;
772 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx
->cpumask
));
774 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
)))
780 * Touch any software queue that has pending entries.
782 flush_busy_ctxs(hctx
, &rq_list
);
785 * If we have previous entries on our dispatch list, grab them
786 * and stuff them at the front for more fair dispatch.
788 if (!list_empty_careful(&hctx
->dispatch
)) {
789 spin_lock(&hctx
->lock
);
790 if (!list_empty(&hctx
->dispatch
))
791 list_splice_init(&hctx
->dispatch
, &rq_list
);
792 spin_unlock(&hctx
->lock
);
796 * Start off with dptr being NULL, so we start the first request
797 * immediately, even if we have more pending.
802 * Now process all the entries, sending them to the driver.
805 while (!list_empty(&rq_list
)) {
806 struct blk_mq_queue_data bd
;
809 rq
= list_first_entry(&rq_list
, struct request
, queuelist
);
810 list_del_init(&rq
->queuelist
);
814 bd
.last
= list_empty(&rq_list
);
816 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
818 case BLK_MQ_RQ_QUEUE_OK
:
821 case BLK_MQ_RQ_QUEUE_BUSY
:
822 list_add(&rq
->queuelist
, &rq_list
);
823 __blk_mq_requeue_request(rq
);
826 pr_err("blk-mq: bad return on queue: %d\n", ret
);
827 case BLK_MQ_RQ_QUEUE_ERROR
:
829 blk_mq_end_request(rq
, rq
->errors
);
833 if (ret
== BLK_MQ_RQ_QUEUE_BUSY
)
837 * We've done the first request. If we have more than 1
838 * left in the list, set dptr to defer issue.
840 if (!dptr
&& rq_list
.next
!= rq_list
.prev
)
845 hctx
->dispatched
[0]++;
846 else if (queued
< (1 << (BLK_MQ_MAX_DISPATCH_ORDER
- 1)))
847 hctx
->dispatched
[ilog2(queued
) + 1]++;
850 * Any items that need requeuing? Stuff them into hctx->dispatch,
851 * that is where we will continue on next queue run.
853 if (!list_empty(&rq_list
)) {
854 spin_lock(&hctx
->lock
);
855 list_splice(&rq_list
, &hctx
->dispatch
);
856 spin_unlock(&hctx
->lock
);
858 * the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but
859 * it's possible the queue is stopped and restarted again
860 * before this. Queue restart will dispatch requests. And since
861 * requests in rq_list aren't added into hctx->dispatch yet,
862 * the requests in rq_list might get lost.
864 * blk_mq_run_hw_queue() already checks the STOPPED bit
866 blk_mq_run_hw_queue(hctx
, true);
871 * It'd be great if the workqueue API had a way to pass
872 * in a mask and had some smarts for more clever placement.
873 * For now we just round-robin here, switching for every
874 * BLK_MQ_CPU_WORK_BATCH queued items.
876 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx
*hctx
)
878 if (hctx
->queue
->nr_hw_queues
== 1)
879 return WORK_CPU_UNBOUND
;
881 if (--hctx
->next_cpu_batch
<= 0) {
882 int cpu
= hctx
->next_cpu
, next_cpu
;
884 next_cpu
= cpumask_next(hctx
->next_cpu
, hctx
->cpumask
);
885 if (next_cpu
>= nr_cpu_ids
)
886 next_cpu
= cpumask_first(hctx
->cpumask
);
888 hctx
->next_cpu
= next_cpu
;
889 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
894 return hctx
->next_cpu
;
897 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx
*hctx
, bool async
)
899 if (unlikely(test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
) ||
900 !blk_mq_hw_queue_mapped(hctx
)))
905 if (cpumask_test_cpu(cpu
, hctx
->cpumask
)) {
906 __blk_mq_run_hw_queue(hctx
);
914 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
918 void blk_mq_run_hw_queues(struct request_queue
*q
, bool async
)
920 struct blk_mq_hw_ctx
*hctx
;
923 queue_for_each_hw_ctx(q
, hctx
, i
) {
924 if ((!blk_mq_hctx_has_pending(hctx
) &&
925 list_empty_careful(&hctx
->dispatch
)) ||
926 test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
929 blk_mq_run_hw_queue(hctx
, async
);
932 EXPORT_SYMBOL(blk_mq_run_hw_queues
);
934 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx
*hctx
)
936 cancel_delayed_work(&hctx
->run_work
);
937 cancel_delayed_work(&hctx
->delay_work
);
938 set_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
940 EXPORT_SYMBOL(blk_mq_stop_hw_queue
);
942 void blk_mq_stop_hw_queues(struct request_queue
*q
)
944 struct blk_mq_hw_ctx
*hctx
;
947 queue_for_each_hw_ctx(q
, hctx
, i
)
948 blk_mq_stop_hw_queue(hctx
);
950 EXPORT_SYMBOL(blk_mq_stop_hw_queues
);
952 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx
*hctx
)
954 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
956 blk_mq_run_hw_queue(hctx
, false);
958 EXPORT_SYMBOL(blk_mq_start_hw_queue
);
960 void blk_mq_start_hw_queues(struct request_queue
*q
)
962 struct blk_mq_hw_ctx
*hctx
;
965 queue_for_each_hw_ctx(q
, hctx
, i
)
966 blk_mq_start_hw_queue(hctx
);
968 EXPORT_SYMBOL(blk_mq_start_hw_queues
);
970 void blk_mq_start_stopped_hw_queues(struct request_queue
*q
, bool async
)
972 struct blk_mq_hw_ctx
*hctx
;
975 queue_for_each_hw_ctx(q
, hctx
, i
) {
976 if (!test_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
979 clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
);
980 blk_mq_run_hw_queue(hctx
, async
);
983 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues
);
985 static void blk_mq_run_work_fn(struct work_struct
*work
)
987 struct blk_mq_hw_ctx
*hctx
;
989 hctx
= container_of(work
, struct blk_mq_hw_ctx
, run_work
.work
);
991 __blk_mq_run_hw_queue(hctx
);
994 static void blk_mq_delay_work_fn(struct work_struct
*work
)
996 struct blk_mq_hw_ctx
*hctx
;
998 hctx
= container_of(work
, struct blk_mq_hw_ctx
, delay_work
.work
);
1000 if (test_and_clear_bit(BLK_MQ_S_STOPPED
, &hctx
->state
))
1001 __blk_mq_run_hw_queue(hctx
);
1004 void blk_mq_delay_queue(struct blk_mq_hw_ctx
*hctx
, unsigned long msecs
)
1006 if (unlikely(!blk_mq_hw_queue_mapped(hctx
)))
1009 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx
),
1010 &hctx
->delay_work
, msecs_to_jiffies(msecs
));
1012 EXPORT_SYMBOL(blk_mq_delay_queue
);
1014 static void __blk_mq_insert_request(struct blk_mq_hw_ctx
*hctx
,
1015 struct request
*rq
, bool at_head
)
1017 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
;
1019 trace_block_rq_insert(hctx
->queue
, rq
);
1022 list_add(&rq
->queuelist
, &ctx
->rq_list
);
1024 list_add_tail(&rq
->queuelist
, &ctx
->rq_list
);
1026 blk_mq_hctx_mark_pending(hctx
, ctx
);
1029 void blk_mq_insert_request(struct request
*rq
, bool at_head
, bool run_queue
,
1032 struct request_queue
*q
= rq
->q
;
1033 struct blk_mq_hw_ctx
*hctx
;
1034 struct blk_mq_ctx
*ctx
= rq
->mq_ctx
, *current_ctx
;
1036 current_ctx
= blk_mq_get_ctx(q
);
1037 if (!cpu_online(ctx
->cpu
))
1038 rq
->mq_ctx
= ctx
= current_ctx
;
1040 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1042 spin_lock(&ctx
->lock
);
1043 __blk_mq_insert_request(hctx
, rq
, at_head
);
1044 spin_unlock(&ctx
->lock
);
1047 blk_mq_run_hw_queue(hctx
, async
);
1049 blk_mq_put_ctx(current_ctx
);
1052 static void blk_mq_insert_requests(struct request_queue
*q
,
1053 struct blk_mq_ctx
*ctx
,
1054 struct list_head
*list
,
1059 struct blk_mq_hw_ctx
*hctx
;
1060 struct blk_mq_ctx
*current_ctx
;
1062 trace_block_unplug(q
, depth
, !from_schedule
);
1064 current_ctx
= blk_mq_get_ctx(q
);
1066 if (!cpu_online(ctx
->cpu
))
1068 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1071 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1074 spin_lock(&ctx
->lock
);
1075 while (!list_empty(list
)) {
1078 rq
= list_first_entry(list
, struct request
, queuelist
);
1079 list_del_init(&rq
->queuelist
);
1081 __blk_mq_insert_request(hctx
, rq
, false);
1083 spin_unlock(&ctx
->lock
);
1085 blk_mq_run_hw_queue(hctx
, from_schedule
);
1086 blk_mq_put_ctx(current_ctx
);
1089 static int plug_ctx_cmp(void *priv
, struct list_head
*a
, struct list_head
*b
)
1091 struct request
*rqa
= container_of(a
, struct request
, queuelist
);
1092 struct request
*rqb
= container_of(b
, struct request
, queuelist
);
1094 return !(rqa
->mq_ctx
< rqb
->mq_ctx
||
1095 (rqa
->mq_ctx
== rqb
->mq_ctx
&&
1096 blk_rq_pos(rqa
) < blk_rq_pos(rqb
)));
1099 void blk_mq_flush_plug_list(struct blk_plug
*plug
, bool from_schedule
)
1101 struct blk_mq_ctx
*this_ctx
;
1102 struct request_queue
*this_q
;
1105 LIST_HEAD(ctx_list
);
1108 list_splice_init(&plug
->mq_list
, &list
);
1110 list_sort(NULL
, &list
, plug_ctx_cmp
);
1116 while (!list_empty(&list
)) {
1117 rq
= list_entry_rq(list
.next
);
1118 list_del_init(&rq
->queuelist
);
1120 if (rq
->mq_ctx
!= this_ctx
) {
1122 blk_mq_insert_requests(this_q
, this_ctx
,
1127 this_ctx
= rq
->mq_ctx
;
1133 list_add_tail(&rq
->queuelist
, &ctx_list
);
1137 * If 'this_ctx' is set, we know we have entries to complete
1138 * on 'ctx_list'. Do those.
1141 blk_mq_insert_requests(this_q
, this_ctx
, &ctx_list
, depth
,
1146 static void blk_mq_bio_to_request(struct request
*rq
, struct bio
*bio
)
1148 init_request_from_bio(rq
, bio
);
1150 if (blk_do_io_stat(rq
))
1151 blk_account_io_start(rq
, 1);
1154 static inline bool hctx_allow_merges(struct blk_mq_hw_ctx
*hctx
)
1156 return (hctx
->flags
& BLK_MQ_F_SHOULD_MERGE
) &&
1157 !blk_queue_nomerges(hctx
->queue
);
1160 static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx
*hctx
,
1161 struct blk_mq_ctx
*ctx
,
1162 struct request
*rq
, struct bio
*bio
)
1164 if (!hctx_allow_merges(hctx
)) {
1165 blk_mq_bio_to_request(rq
, bio
);
1166 spin_lock(&ctx
->lock
);
1168 __blk_mq_insert_request(hctx
, rq
, false);
1169 spin_unlock(&ctx
->lock
);
1172 struct request_queue
*q
= hctx
->queue
;
1174 spin_lock(&ctx
->lock
);
1175 if (!blk_mq_attempt_merge(q
, ctx
, bio
)) {
1176 blk_mq_bio_to_request(rq
, bio
);
1180 spin_unlock(&ctx
->lock
);
1181 __blk_mq_free_request(hctx
, ctx
, rq
);
1186 struct blk_map_ctx
{
1187 struct blk_mq_hw_ctx
*hctx
;
1188 struct blk_mq_ctx
*ctx
;
1191 static struct request
*blk_mq_map_request(struct request_queue
*q
,
1193 struct blk_map_ctx
*data
)
1195 struct blk_mq_hw_ctx
*hctx
;
1196 struct blk_mq_ctx
*ctx
;
1198 int rw
= bio_data_dir(bio
);
1199 struct blk_mq_alloc_data alloc_data
;
1201 if (unlikely(blk_mq_queue_enter(q
, GFP_KERNEL
))) {
1206 ctx
= blk_mq_get_ctx(q
);
1207 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1209 if (rw_is_sync(bio
->bi_rw
))
1212 trace_block_getrq(q
, bio
, rw
);
1213 blk_mq_set_alloc_data(&alloc_data
, q
, GFP_ATOMIC
, false, ctx
,
1215 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1216 if (unlikely(!rq
)) {
1217 __blk_mq_run_hw_queue(hctx
);
1218 blk_mq_put_ctx(ctx
);
1219 trace_block_sleeprq(q
, bio
, rw
);
1221 ctx
= blk_mq_get_ctx(q
);
1222 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1223 blk_mq_set_alloc_data(&alloc_data
, q
,
1224 __GFP_WAIT
|GFP_ATOMIC
, false, ctx
, hctx
);
1225 rq
= __blk_mq_alloc_request(&alloc_data
, rw
);
1226 ctx
= alloc_data
.ctx
;
1227 hctx
= alloc_data
.hctx
;
1236 static int blk_mq_direct_issue_request(struct request
*rq
)
1239 struct request_queue
*q
= rq
->q
;
1240 struct blk_mq_hw_ctx
*hctx
= q
->mq_ops
->map_queue(q
,
1242 struct blk_mq_queue_data bd
= {
1249 * For OK queue, we are done. For error, kill it. Any other
1250 * error (busy), just add it to our list as we previously
1253 ret
= q
->mq_ops
->queue_rq(hctx
, &bd
);
1254 if (ret
== BLK_MQ_RQ_QUEUE_OK
)
1257 __blk_mq_requeue_request(rq
);
1259 if (ret
== BLK_MQ_RQ_QUEUE_ERROR
) {
1261 blk_mq_end_request(rq
, rq
->errors
);
1269 * Multiple hardware queue variant. This will not use per-process plugs,
1270 * but will attempt to bypass the hctx queueing if we can go straight to
1271 * hardware for SYNC IO.
1273 static void blk_mq_make_request(struct request_queue
*q
, struct bio
*bio
)
1275 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1276 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1277 struct blk_map_ctx data
;
1279 unsigned int request_count
= 0;
1280 struct blk_plug
*plug
;
1281 struct request
*same_queue_rq
= NULL
;
1283 blk_queue_bounce(q
, &bio
);
1285 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1290 blk_queue_split(q
, &bio
, q
->bio_split
);
1292 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
1293 blk_attempt_plug_merge(q
, bio
, &request_count
, &same_queue_rq
))
1296 rq
= blk_mq_map_request(q
, bio
, &data
);
1300 if (unlikely(is_flush_fua
)) {
1301 blk_mq_bio_to_request(rq
, bio
);
1302 blk_insert_flush(rq
);
1306 plug
= current
->plug
;
1308 * If the driver supports defer issued based on 'last', then
1309 * queue it up like normal since we can potentially save some
1312 if (((plug
&& !blk_queue_nomerges(q
)) || is_sync
) &&
1313 !(data
.hctx
->flags
& BLK_MQ_F_DEFER_ISSUE
)) {
1314 struct request
*old_rq
= NULL
;
1316 blk_mq_bio_to_request(rq
, bio
);
1319 * we do limited pluging. If bio can be merged, do merge.
1320 * Otherwise the existing request in the plug list will be
1321 * issued. So the plug list will have one request at most
1325 * The plug list might get flushed before this. If that
1326 * happens, same_queue_rq is invalid and plug list is empty
1328 if (same_queue_rq
&& !list_empty(&plug
->mq_list
)) {
1329 old_rq
= same_queue_rq
;
1330 list_del_init(&old_rq
->queuelist
);
1332 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1333 } else /* is_sync */
1335 blk_mq_put_ctx(data
.ctx
);
1338 if (!blk_mq_direct_issue_request(old_rq
))
1340 blk_mq_insert_request(old_rq
, false, true, true);
1344 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1346 * For a SYNC request, send it to the hardware immediately. For
1347 * an ASYNC request, just ensure that we run it later on. The
1348 * latter allows for merging opportunities and more efficient
1352 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1354 blk_mq_put_ctx(data
.ctx
);
1358 * Single hardware queue variant. This will attempt to use any per-process
1359 * plug for merging and IO deferral.
1361 static void blk_sq_make_request(struct request_queue
*q
, struct bio
*bio
)
1363 const int is_sync
= rw_is_sync(bio
->bi_rw
);
1364 const int is_flush_fua
= bio
->bi_rw
& (REQ_FLUSH
| REQ_FUA
);
1365 struct blk_plug
*plug
;
1366 unsigned int request_count
= 0;
1367 struct blk_map_ctx data
;
1370 blk_queue_bounce(q
, &bio
);
1372 if (bio_integrity_enabled(bio
) && bio_integrity_prep(bio
)) {
1377 blk_queue_split(q
, &bio
, q
->bio_split
);
1379 if (!is_flush_fua
&& !blk_queue_nomerges(q
) &&
1380 blk_attempt_plug_merge(q
, bio
, &request_count
, NULL
))
1383 rq
= blk_mq_map_request(q
, bio
, &data
);
1387 if (unlikely(is_flush_fua
)) {
1388 blk_mq_bio_to_request(rq
, bio
);
1389 blk_insert_flush(rq
);
1394 * A task plug currently exists. Since this is completely lockless,
1395 * utilize that to temporarily store requests until the task is
1396 * either done or scheduled away.
1398 plug
= current
->plug
;
1400 blk_mq_bio_to_request(rq
, bio
);
1401 if (list_empty(&plug
->mq_list
))
1402 trace_block_plug(q
);
1403 else if (request_count
>= BLK_MAX_REQUEST_COUNT
) {
1404 blk_flush_plug_list(plug
, false);
1405 trace_block_plug(q
);
1407 list_add_tail(&rq
->queuelist
, &plug
->mq_list
);
1408 blk_mq_put_ctx(data
.ctx
);
1412 if (!blk_mq_merge_queue_io(data
.hctx
, data
.ctx
, rq
, bio
)) {
1414 * For a SYNC request, send it to the hardware immediately. For
1415 * an ASYNC request, just ensure that we run it later on. The
1416 * latter allows for merging opportunities and more efficient
1420 blk_mq_run_hw_queue(data
.hctx
, !is_sync
|| is_flush_fua
);
1423 blk_mq_put_ctx(data
.ctx
);
1427 * Default mapping to a software queue, since we use one per CPU.
1429 struct blk_mq_hw_ctx
*blk_mq_map_queue(struct request_queue
*q
, const int cpu
)
1431 return q
->queue_hw_ctx
[q
->mq_map
[cpu
]];
1433 EXPORT_SYMBOL(blk_mq_map_queue
);
1435 static void blk_mq_free_rq_map(struct blk_mq_tag_set
*set
,
1436 struct blk_mq_tags
*tags
, unsigned int hctx_idx
)
1440 if (tags
->rqs
&& set
->ops
->exit_request
) {
1443 for (i
= 0; i
< tags
->nr_tags
; i
++) {
1446 set
->ops
->exit_request(set
->driver_data
, tags
->rqs
[i
],
1448 tags
->rqs
[i
] = NULL
;
1452 while (!list_empty(&tags
->page_list
)) {
1453 page
= list_first_entry(&tags
->page_list
, struct page
, lru
);
1454 list_del_init(&page
->lru
);
1455 __free_pages(page
, page
->private);
1460 blk_mq_free_tags(tags
);
1463 static size_t order_to_size(unsigned int order
)
1465 return (size_t)PAGE_SIZE
<< order
;
1468 static struct blk_mq_tags
*blk_mq_init_rq_map(struct blk_mq_tag_set
*set
,
1469 unsigned int hctx_idx
)
1471 struct blk_mq_tags
*tags
;
1472 unsigned int i
, j
, entries_per_page
, max_order
= 4;
1473 size_t rq_size
, left
;
1475 tags
= blk_mq_init_tags(set
->queue_depth
, set
->reserved_tags
,
1477 BLK_MQ_FLAG_TO_ALLOC_POLICY(set
->flags
));
1481 INIT_LIST_HEAD(&tags
->page_list
);
1483 tags
->rqs
= kzalloc_node(set
->queue_depth
* sizeof(struct request
*),
1484 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
,
1487 blk_mq_free_tags(tags
);
1492 * rq_size is the size of the request plus driver payload, rounded
1493 * to the cacheline size
1495 rq_size
= round_up(sizeof(struct request
) + set
->cmd_size
,
1497 left
= rq_size
* set
->queue_depth
;
1499 for (i
= 0; i
< set
->queue_depth
; ) {
1500 int this_order
= max_order
;
1505 while (left
< order_to_size(this_order
- 1) && this_order
)
1509 page
= alloc_pages_node(set
->numa_node
,
1510 GFP_KERNEL
| __GFP_NOWARN
| __GFP_NORETRY
| __GFP_ZERO
,
1516 if (order_to_size(this_order
) < rq_size
)
1523 page
->private = this_order
;
1524 list_add_tail(&page
->lru
, &tags
->page_list
);
1526 p
= page_address(page
);
1527 entries_per_page
= order_to_size(this_order
) / rq_size
;
1528 to_do
= min(entries_per_page
, set
->queue_depth
- i
);
1529 left
-= to_do
* rq_size
;
1530 for (j
= 0; j
< to_do
; j
++) {
1532 if (set
->ops
->init_request
) {
1533 if (set
->ops
->init_request(set
->driver_data
,
1534 tags
->rqs
[i
], hctx_idx
, i
,
1536 tags
->rqs
[i
] = NULL
;
1548 blk_mq_free_rq_map(set
, tags
, hctx_idx
);
1552 static void blk_mq_free_bitmap(struct blk_mq_ctxmap
*bitmap
)
1557 static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap
*bitmap
, int node
)
1559 unsigned int bpw
= 8, total
, num_maps
, i
;
1561 bitmap
->bits_per_word
= bpw
;
1563 num_maps
= ALIGN(nr_cpu_ids
, bpw
) / bpw
;
1564 bitmap
->map
= kzalloc_node(num_maps
* sizeof(struct blk_align_bitmap
),
1570 for (i
= 0; i
< num_maps
; i
++) {
1571 bitmap
->map
[i
].depth
= min(total
, bitmap
->bits_per_word
);
1572 total
-= bitmap
->map
[i
].depth
;
1578 static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx
*hctx
, int cpu
)
1580 struct request_queue
*q
= hctx
->queue
;
1581 struct blk_mq_ctx
*ctx
;
1585 * Move ctx entries to new CPU, if this one is going away.
1587 ctx
= __blk_mq_get_ctx(q
, cpu
);
1589 spin_lock(&ctx
->lock
);
1590 if (!list_empty(&ctx
->rq_list
)) {
1591 list_splice_init(&ctx
->rq_list
, &tmp
);
1592 blk_mq_hctx_clear_pending(hctx
, ctx
);
1594 spin_unlock(&ctx
->lock
);
1596 if (list_empty(&tmp
))
1599 ctx
= blk_mq_get_ctx(q
);
1600 spin_lock(&ctx
->lock
);
1602 while (!list_empty(&tmp
)) {
1605 rq
= list_first_entry(&tmp
, struct request
, queuelist
);
1607 list_move_tail(&rq
->queuelist
, &ctx
->rq_list
);
1610 hctx
= q
->mq_ops
->map_queue(q
, ctx
->cpu
);
1611 blk_mq_hctx_mark_pending(hctx
, ctx
);
1613 spin_unlock(&ctx
->lock
);
1615 blk_mq_run_hw_queue(hctx
, true);
1616 blk_mq_put_ctx(ctx
);
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
);
1629 * In case of CPU online, tags may be reallocated
1630 * in blk_mq_map_swqueue() after mapping is updated.
1636 /* hctx->ctxs will be freed in queue's release handler */
1637 static void blk_mq_exit_hctx(struct request_queue
*q
,
1638 struct blk_mq_tag_set
*set
,
1639 struct blk_mq_hw_ctx
*hctx
, unsigned int hctx_idx
)
1641 unsigned flush_start_tag
= set
->queue_depth
;
1643 blk_mq_tag_idle(hctx
);
1645 if (set
->ops
->exit_request
)
1646 set
->ops
->exit_request(set
->driver_data
,
1647 hctx
->fq
->flush_rq
, hctx_idx
,
1648 flush_start_tag
+ hctx_idx
);
1650 if (set
->ops
->exit_hctx
)
1651 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1653 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1654 blk_free_flush_queue(hctx
->fq
);
1655 blk_mq_free_bitmap(&hctx
->ctx_map
);
1658 static void blk_mq_exit_hw_queues(struct request_queue
*q
,
1659 struct blk_mq_tag_set
*set
, int nr_queue
)
1661 struct blk_mq_hw_ctx
*hctx
;
1664 queue_for_each_hw_ctx(q
, hctx
, i
) {
1667 blk_mq_exit_hctx(q
, set
, hctx
, i
);
1671 static void blk_mq_free_hw_queues(struct request_queue
*q
,
1672 struct blk_mq_tag_set
*set
)
1674 struct blk_mq_hw_ctx
*hctx
;
1677 queue_for_each_hw_ctx(q
, hctx
, i
)
1678 free_cpumask_var(hctx
->cpumask
);
1681 static int blk_mq_init_hctx(struct request_queue
*q
,
1682 struct blk_mq_tag_set
*set
,
1683 struct blk_mq_hw_ctx
*hctx
, unsigned hctx_idx
)
1686 unsigned flush_start_tag
= set
->queue_depth
;
1688 node
= hctx
->numa_node
;
1689 if (node
== NUMA_NO_NODE
)
1690 node
= hctx
->numa_node
= set
->numa_node
;
1692 INIT_DELAYED_WORK(&hctx
->run_work
, blk_mq_run_work_fn
);
1693 INIT_DELAYED_WORK(&hctx
->delay_work
, blk_mq_delay_work_fn
);
1694 spin_lock_init(&hctx
->lock
);
1695 INIT_LIST_HEAD(&hctx
->dispatch
);
1697 hctx
->queue_num
= hctx_idx
;
1698 hctx
->flags
= set
->flags
;
1700 blk_mq_init_cpu_notifier(&hctx
->cpu_notifier
,
1701 blk_mq_hctx_notify
, hctx
);
1702 blk_mq_register_cpu_notifier(&hctx
->cpu_notifier
);
1704 hctx
->tags
= set
->tags
[hctx_idx
];
1707 * Allocate space for all possible cpus to avoid allocation at
1710 hctx
->ctxs
= kmalloc_node(nr_cpu_ids
* sizeof(void *),
1713 goto unregister_cpu_notifier
;
1715 if (blk_mq_alloc_bitmap(&hctx
->ctx_map
, node
))
1720 if (set
->ops
->init_hctx
&&
1721 set
->ops
->init_hctx(hctx
, set
->driver_data
, hctx_idx
))
1724 hctx
->fq
= blk_alloc_flush_queue(q
, hctx
->numa_node
, set
->cmd_size
);
1728 if (set
->ops
->init_request
&&
1729 set
->ops
->init_request(set
->driver_data
,
1730 hctx
->fq
->flush_rq
, hctx_idx
,
1731 flush_start_tag
+ hctx_idx
, node
))
1739 if (set
->ops
->exit_hctx
)
1740 set
->ops
->exit_hctx(hctx
, hctx_idx
);
1742 blk_mq_free_bitmap(&hctx
->ctx_map
);
1745 unregister_cpu_notifier
:
1746 blk_mq_unregister_cpu_notifier(&hctx
->cpu_notifier
);
1751 static int blk_mq_init_hw_queues(struct request_queue
*q
,
1752 struct blk_mq_tag_set
*set
)
1754 struct blk_mq_hw_ctx
*hctx
;
1758 * Initialize hardware queues
1760 queue_for_each_hw_ctx(q
, hctx
, i
) {
1761 if (blk_mq_init_hctx(q
, set
, hctx
, i
))
1765 if (i
== q
->nr_hw_queues
)
1771 blk_mq_exit_hw_queues(q
, set
, i
);
1776 static void blk_mq_init_cpu_queues(struct request_queue
*q
,
1777 unsigned int nr_hw_queues
)
1781 for_each_possible_cpu(i
) {
1782 struct blk_mq_ctx
*__ctx
= per_cpu_ptr(q
->queue_ctx
, i
);
1783 struct blk_mq_hw_ctx
*hctx
;
1785 memset(__ctx
, 0, sizeof(*__ctx
));
1787 spin_lock_init(&__ctx
->lock
);
1788 INIT_LIST_HEAD(&__ctx
->rq_list
);
1791 /* If the cpu isn't online, the cpu is mapped to first hctx */
1795 hctx
= q
->mq_ops
->map_queue(q
, i
);
1798 * Set local node, IFF we have more than one hw queue. If
1799 * not, we remain on the home node of the device
1801 if (nr_hw_queues
> 1 && hctx
->numa_node
== NUMA_NO_NODE
)
1802 hctx
->numa_node
= cpu_to_node(i
);
1806 static void blk_mq_map_swqueue(struct request_queue
*q
)
1809 struct blk_mq_hw_ctx
*hctx
;
1810 struct blk_mq_ctx
*ctx
;
1811 struct blk_mq_tag_set
*set
= q
->tag_set
;
1813 queue_for_each_hw_ctx(q
, hctx
, i
) {
1814 cpumask_clear(hctx
->cpumask
);
1819 * Map software to hardware queues
1821 queue_for_each_ctx(q
, ctx
, i
) {
1822 /* If the cpu isn't online, the cpu is mapped to first hctx */
1826 hctx
= q
->mq_ops
->map_queue(q
, i
);
1827 cpumask_set_cpu(i
, hctx
->cpumask
);
1828 cpumask_set_cpu(i
, hctx
->tags
->cpumask
);
1829 ctx
->index_hw
= hctx
->nr_ctx
;
1830 hctx
->ctxs
[hctx
->nr_ctx
++] = ctx
;
1833 queue_for_each_hw_ctx(q
, hctx
, i
) {
1834 struct blk_mq_ctxmap
*map
= &hctx
->ctx_map
;
1837 * If no software queues are mapped to this hardware queue,
1838 * disable it and free the request entries.
1840 if (!hctx
->nr_ctx
) {
1842 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
1843 set
->tags
[i
] = NULL
;
1849 /* unmapped hw queue can be remapped after CPU topo changed */
1851 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
1852 hctx
->tags
= set
->tags
[i
];
1853 WARN_ON(!hctx
->tags
);
1856 * Set the map size to the number of mapped software queues.
1857 * This is more accurate and more efficient than looping
1858 * over all possibly mapped software queues.
1860 map
->size
= DIV_ROUND_UP(hctx
->nr_ctx
, map
->bits_per_word
);
1863 * Initialize batch roundrobin counts
1865 hctx
->next_cpu
= cpumask_first(hctx
->cpumask
);
1866 hctx
->next_cpu_batch
= BLK_MQ_CPU_WORK_BATCH
;
1870 static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set
*set
)
1872 struct blk_mq_hw_ctx
*hctx
;
1873 struct request_queue
*q
;
1877 if (set
->tag_list
.next
== set
->tag_list
.prev
)
1882 list_for_each_entry(q
, &set
->tag_list
, tag_set_list
) {
1883 blk_mq_freeze_queue(q
);
1885 queue_for_each_hw_ctx(q
, hctx
, i
) {
1887 hctx
->flags
|= BLK_MQ_F_TAG_SHARED
;
1889 hctx
->flags
&= ~BLK_MQ_F_TAG_SHARED
;
1891 blk_mq_unfreeze_queue(q
);
1895 static void blk_mq_del_queue_tag_set(struct request_queue
*q
)
1897 struct blk_mq_tag_set
*set
= q
->tag_set
;
1899 mutex_lock(&set
->tag_list_lock
);
1900 list_del_init(&q
->tag_set_list
);
1901 blk_mq_update_tag_set_depth(set
);
1902 mutex_unlock(&set
->tag_list_lock
);
1905 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set
*set
,
1906 struct request_queue
*q
)
1910 mutex_lock(&set
->tag_list_lock
);
1911 list_add_tail(&q
->tag_set_list
, &set
->tag_list
);
1912 blk_mq_update_tag_set_depth(set
);
1913 mutex_unlock(&set
->tag_list_lock
);
1917 * It is the actual release handler for mq, but we do it from
1918 * request queue's release handler for avoiding use-after-free
1919 * and headache because q->mq_kobj shouldn't have been introduced,
1920 * but we can't group ctx/kctx kobj without it.
1922 void blk_mq_release(struct request_queue
*q
)
1924 struct blk_mq_hw_ctx
*hctx
;
1927 /* hctx kobj stays in hctx */
1928 queue_for_each_hw_ctx(q
, hctx
, i
) {
1935 kfree(q
->queue_hw_ctx
);
1937 /* ctx kobj stays in queue_ctx */
1938 free_percpu(q
->queue_ctx
);
1941 struct request_queue
*blk_mq_init_queue(struct blk_mq_tag_set
*set
)
1943 struct request_queue
*uninit_q
, *q
;
1945 uninit_q
= blk_alloc_queue_node(GFP_KERNEL
, set
->numa_node
);
1947 return ERR_PTR(-ENOMEM
);
1949 q
= blk_mq_init_allocated_queue(set
, uninit_q
);
1951 blk_cleanup_queue(uninit_q
);
1955 EXPORT_SYMBOL(blk_mq_init_queue
);
1957 struct request_queue
*blk_mq_init_allocated_queue(struct blk_mq_tag_set
*set
,
1958 struct request_queue
*q
)
1960 struct blk_mq_hw_ctx
**hctxs
;
1961 struct blk_mq_ctx __percpu
*ctx
;
1965 ctx
= alloc_percpu(struct blk_mq_ctx
);
1967 return ERR_PTR(-ENOMEM
);
1969 hctxs
= kmalloc_node(set
->nr_hw_queues
* sizeof(*hctxs
), GFP_KERNEL
,
1975 map
= blk_mq_make_queue_map(set
);
1979 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
1980 int node
= blk_mq_hw_queue_to_node(map
, i
);
1982 hctxs
[i
] = kzalloc_node(sizeof(struct blk_mq_hw_ctx
),
1987 if (!zalloc_cpumask_var_node(&hctxs
[i
]->cpumask
, GFP_KERNEL
,
1991 atomic_set(&hctxs
[i
]->nr_active
, 0);
1992 hctxs
[i
]->numa_node
= node
;
1993 hctxs
[i
]->queue_num
= i
;
1997 * Init percpu_ref in atomic mode so that it's faster to shutdown.
1998 * See blk_register_queue() for details.
2000 if (percpu_ref_init(&q
->mq_usage_counter
, blk_mq_usage_counter_release
,
2001 PERCPU_REF_INIT_ATOMIC
, GFP_KERNEL
))
2004 setup_timer(&q
->timeout
, blk_mq_rq_timer
, (unsigned long) q
);
2005 blk_queue_rq_timeout(q
, set
->timeout
? set
->timeout
: 30 * HZ
);
2007 q
->nr_queues
= nr_cpu_ids
;
2008 q
->nr_hw_queues
= set
->nr_hw_queues
;
2012 q
->queue_hw_ctx
= hctxs
;
2014 q
->mq_ops
= set
->ops
;
2015 q
->queue_flags
|= QUEUE_FLAG_MQ_DEFAULT
;
2017 if (!(set
->flags
& BLK_MQ_F_SG_MERGE
))
2018 q
->queue_flags
|= 1 << QUEUE_FLAG_NO_SG_MERGE
;
2020 q
->sg_reserved_size
= INT_MAX
;
2022 INIT_WORK(&q
->requeue_work
, blk_mq_requeue_work
);
2023 INIT_LIST_HEAD(&q
->requeue_list
);
2024 spin_lock_init(&q
->requeue_lock
);
2026 if (q
->nr_hw_queues
> 1)
2027 blk_queue_make_request(q
, blk_mq_make_request
);
2029 blk_queue_make_request(q
, blk_sq_make_request
);
2032 * Do this after blk_queue_make_request() overrides it...
2034 q
->nr_requests
= set
->queue_depth
;
2036 if (set
->ops
->complete
)
2037 blk_queue_softirq_done(q
, set
->ops
->complete
);
2039 blk_mq_init_cpu_queues(q
, set
->nr_hw_queues
);
2041 if (blk_mq_init_hw_queues(q
, set
))
2044 mutex_lock(&all_q_mutex
);
2045 list_add_tail(&q
->all_q_node
, &all_q_list
);
2046 mutex_unlock(&all_q_mutex
);
2048 blk_mq_add_queue_tag_set(set
, q
);
2050 blk_mq_map_swqueue(q
);
2056 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2059 free_cpumask_var(hctxs
[i
]->cpumask
);
2066 return ERR_PTR(-ENOMEM
);
2068 EXPORT_SYMBOL(blk_mq_init_allocated_queue
);
2070 void blk_mq_free_queue(struct request_queue
*q
)
2072 struct blk_mq_tag_set
*set
= q
->tag_set
;
2074 blk_mq_del_queue_tag_set(q
);
2076 blk_mq_exit_hw_queues(q
, set
, set
->nr_hw_queues
);
2077 blk_mq_free_hw_queues(q
, set
);
2079 percpu_ref_exit(&q
->mq_usage_counter
);
2085 mutex_lock(&all_q_mutex
);
2086 list_del_init(&q
->all_q_node
);
2087 mutex_unlock(&all_q_mutex
);
2090 /* Basically redo blk_mq_init_queue with queue frozen */
2091 static void blk_mq_queue_reinit(struct request_queue
*q
)
2093 WARN_ON_ONCE(!atomic_read(&q
->mq_freeze_depth
));
2095 blk_mq_sysfs_unregister(q
);
2097 blk_mq_update_queue_map(q
->mq_map
, q
->nr_hw_queues
);
2100 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
2101 * we should change hctx numa_node according to new topology (this
2102 * involves free and re-allocate memory, worthy doing?)
2105 blk_mq_map_swqueue(q
);
2107 blk_mq_sysfs_register(q
);
2110 static int blk_mq_queue_reinit_notify(struct notifier_block
*nb
,
2111 unsigned long action
, void *hcpu
)
2113 struct request_queue
*q
;
2116 * Before new mappings are established, hotadded cpu might already
2117 * start handling requests. This doesn't break anything as we map
2118 * offline CPUs to first hardware queue. We will re-init the queue
2119 * below to get optimal settings.
2121 if (action
!= CPU_DEAD
&& action
!= CPU_DEAD_FROZEN
&&
2122 action
!= CPU_ONLINE
&& action
!= CPU_ONLINE_FROZEN
)
2125 mutex_lock(&all_q_mutex
);
2128 * We need to freeze and reinit all existing queues. Freezing
2129 * involves synchronous wait for an RCU grace period and doing it
2130 * one by one may take a long time. Start freezing all queues in
2131 * one swoop and then wait for the completions so that freezing can
2132 * take place in parallel.
2134 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2135 blk_mq_freeze_queue_start(q
);
2136 list_for_each_entry(q
, &all_q_list
, all_q_node
) {
2137 blk_mq_freeze_queue_wait(q
);
2140 * timeout handler can't touch hw queue during the
2143 del_timer_sync(&q
->timeout
);
2146 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2147 blk_mq_queue_reinit(q
);
2149 list_for_each_entry(q
, &all_q_list
, all_q_node
)
2150 blk_mq_unfreeze_queue(q
);
2152 mutex_unlock(&all_q_mutex
);
2156 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2160 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2161 set
->tags
[i
] = blk_mq_init_rq_map(set
, i
);
2170 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2176 * Allocate the request maps associated with this tag_set. Note that this
2177 * may reduce the depth asked for, if memory is tight. set->queue_depth
2178 * will be updated to reflect the allocated depth.
2180 static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set
*set
)
2185 depth
= set
->queue_depth
;
2187 err
= __blk_mq_alloc_rq_maps(set
);
2191 set
->queue_depth
>>= 1;
2192 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
) {
2196 } while (set
->queue_depth
);
2198 if (!set
->queue_depth
|| err
) {
2199 pr_err("blk-mq: failed to allocate request map\n");
2203 if (depth
!= set
->queue_depth
)
2204 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2205 depth
, set
->queue_depth
);
2210 struct cpumask
*blk_mq_tags_cpumask(struct blk_mq_tags
*tags
)
2212 return tags
->cpumask
;
2214 EXPORT_SYMBOL_GPL(blk_mq_tags_cpumask
);
2217 * Alloc a tag set to be associated with one or more request queues.
2218 * May fail with EINVAL for various error conditions. May adjust the
2219 * requested depth down, if if it too large. In that case, the set
2220 * value will be stored in set->queue_depth.
2222 int blk_mq_alloc_tag_set(struct blk_mq_tag_set
*set
)
2224 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH
> 1 << BLK_MQ_UNIQUE_TAG_BITS
);
2226 if (!set
->nr_hw_queues
)
2228 if (!set
->queue_depth
)
2230 if (set
->queue_depth
< set
->reserved_tags
+ BLK_MQ_TAG_MIN
)
2233 if (!set
->ops
->queue_rq
|| !set
->ops
->map_queue
)
2236 if (set
->queue_depth
> BLK_MQ_MAX_DEPTH
) {
2237 pr_info("blk-mq: reduced tag depth to %u\n",
2239 set
->queue_depth
= BLK_MQ_MAX_DEPTH
;
2243 * If a crashdump is active, then we are potentially in a very
2244 * memory constrained environment. Limit us to 1 queue and
2245 * 64 tags to prevent using too much memory.
2247 if (is_kdump_kernel()) {
2248 set
->nr_hw_queues
= 1;
2249 set
->queue_depth
= min(64U, set
->queue_depth
);
2252 set
->tags
= kmalloc_node(set
->nr_hw_queues
*
2253 sizeof(struct blk_mq_tags
*),
2254 GFP_KERNEL
, set
->numa_node
);
2258 if (blk_mq_alloc_rq_maps(set
))
2261 mutex_init(&set
->tag_list_lock
);
2262 INIT_LIST_HEAD(&set
->tag_list
);
2270 EXPORT_SYMBOL(blk_mq_alloc_tag_set
);
2272 void blk_mq_free_tag_set(struct blk_mq_tag_set
*set
)
2276 for (i
= 0; i
< set
->nr_hw_queues
; i
++) {
2278 blk_mq_free_rq_map(set
, set
->tags
[i
], i
);
2279 free_cpumask_var(set
->tags
[i
]->cpumask
);
2286 EXPORT_SYMBOL(blk_mq_free_tag_set
);
2288 int blk_mq_update_nr_requests(struct request_queue
*q
, unsigned int nr
)
2290 struct blk_mq_tag_set
*set
= q
->tag_set
;
2291 struct blk_mq_hw_ctx
*hctx
;
2294 if (!set
|| nr
> set
->queue_depth
)
2298 queue_for_each_hw_ctx(q
, hctx
, i
) {
2299 ret
= blk_mq_tag_update_depth(hctx
->tags
, nr
);
2305 q
->nr_requests
= nr
;
2310 void blk_mq_disable_hotplug(void)
2312 mutex_lock(&all_q_mutex
);
2315 void blk_mq_enable_hotplug(void)
2317 mutex_unlock(&all_q_mutex
);
2320 static int __init
blk_mq_init(void)
2324 hotcpu_notifier(blk_mq_queue_reinit_notify
, 0);
2328 subsys_initcall(blk_mq_init
);