Merge tag 'metag-for-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jhoga...
[linux-2.6-block.git] / block / blk-mq.c
CommitLineData
75bb4625
JA
1/*
2 * Block multiqueue core code
3 *
4 * Copyright (C) 2013-2014 Jens Axboe
5 * Copyright (C) 2013-2014 Christoph Hellwig
6 */
320ae51f
JA
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>
f75782e4 12#include <linux/kmemleak.h>
320ae51f
JA
13#include <linux/mm.h>
14#include <linux/init.h>
15#include <linux/slab.h>
16#include <linux/workqueue.h>
17#include <linux/smp.h>
18#include <linux/llist.h>
19#include <linux/list_sort.h>
20#include <linux/cpu.h>
21#include <linux/cache.h>
22#include <linux/sched/sysctl.h>
23#include <linux/delay.h>
aedcd72f 24#include <linux/crash_dump.h>
88c7b2b7 25#include <linux/prefetch.h>
320ae51f
JA
26
27#include <trace/events/block.h>
28
29#include <linux/blk-mq.h>
30#include "blk.h"
31#include "blk-mq.h"
32#include "blk-mq-tag.h"
33
34static DEFINE_MUTEX(all_q_mutex);
35static LIST_HEAD(all_q_list);
36
320ae51f
JA
37/*
38 * Check if any of the ctx's have pending work in this hardware queue
39 */
40static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
41{
88459642 42 return sbitmap_any_bit_set(&hctx->ctx_map);
1429d7c9
JA
43}
44
320ae51f
JA
45/*
46 * Mark this ctx as having pending work in this hardware queue
47 */
48static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
49 struct blk_mq_ctx *ctx)
50{
88459642
OS
51 if (!sbitmap_test_bit(&hctx->ctx_map, ctx->index_hw))
52 sbitmap_set_bit(&hctx->ctx_map, ctx->index_hw);
1429d7c9
JA
53}
54
55static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
56 struct blk_mq_ctx *ctx)
57{
88459642 58 sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
320ae51f
JA
59}
60
b4c6a028 61void blk_mq_freeze_queue_start(struct request_queue *q)
43a5e4e2 62{
4ecd4fef 63 int freeze_depth;
cddd5d17 64
4ecd4fef
CH
65 freeze_depth = atomic_inc_return(&q->mq_freeze_depth);
66 if (freeze_depth == 1) {
3ef28e83 67 percpu_ref_kill(&q->q_usage_counter);
b94ec296 68 blk_mq_run_hw_queues(q, false);
cddd5d17 69 }
f3af020b 70}
b4c6a028 71EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start);
f3af020b
TH
72
73static void blk_mq_freeze_queue_wait(struct request_queue *q)
74{
3ef28e83 75 wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
43a5e4e2
ML
76}
77
f3af020b
TH
78/*
79 * Guarantee no request is in use, so we can change any data structure of
80 * the queue afterward.
81 */
3ef28e83 82void blk_freeze_queue(struct request_queue *q)
f3af020b 83{
3ef28e83
DW
84 /*
85 * In the !blk_mq case we are only calling this to kill the
86 * q_usage_counter, otherwise this increases the freeze depth
87 * and waits for it to return to zero. For this reason there is
88 * no blk_unfreeze_queue(), and blk_freeze_queue() is not
89 * exported to drivers as the only user for unfreeze is blk_mq.
90 */
f3af020b
TH
91 blk_mq_freeze_queue_start(q);
92 blk_mq_freeze_queue_wait(q);
93}
3ef28e83
DW
94
95void blk_mq_freeze_queue(struct request_queue *q)
96{
97 /*
98 * ...just an alias to keep freeze and unfreeze actions balanced
99 * in the blk_mq_* namespace
100 */
101 blk_freeze_queue(q);
102}
c761d96b 103EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
f3af020b 104
b4c6a028 105void blk_mq_unfreeze_queue(struct request_queue *q)
320ae51f 106{
4ecd4fef 107 int freeze_depth;
320ae51f 108
4ecd4fef
CH
109 freeze_depth = atomic_dec_return(&q->mq_freeze_depth);
110 WARN_ON_ONCE(freeze_depth < 0);
111 if (!freeze_depth) {
3ef28e83 112 percpu_ref_reinit(&q->q_usage_counter);
320ae51f 113 wake_up_all(&q->mq_freeze_wq);
add703fd 114 }
320ae51f 115}
b4c6a028 116EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
320ae51f 117
aed3ea94
JA
118void blk_mq_wake_waiters(struct request_queue *q)
119{
120 struct blk_mq_hw_ctx *hctx;
121 unsigned int i;
122
123 queue_for_each_hw_ctx(q, hctx, i)
124 if (blk_mq_hw_queue_mapped(hctx))
125 blk_mq_tag_wakeup_all(hctx->tags, true);
3fd5940c
KB
126
127 /*
128 * If we are called because the queue has now been marked as
129 * dying, we need to ensure that processes currently waiting on
130 * the queue are notified as well.
131 */
132 wake_up_all(&q->mq_freeze_wq);
aed3ea94
JA
133}
134
320ae51f
JA
135bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
136{
137 return blk_mq_has_free_tags(hctx->tags);
138}
139EXPORT_SYMBOL(blk_mq_can_queue);
140
94eddfbe 141static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
cc6e3b10
MC
142 struct request *rq, int op,
143 unsigned int op_flags)
320ae51f 144{
94eddfbe 145 if (blk_queue_io_stat(q))
cc6e3b10 146 op_flags |= REQ_IO_STAT;
94eddfbe 147
af76e555
CH
148 INIT_LIST_HEAD(&rq->queuelist);
149 /* csd/requeue_work/fifo_time is initialized before use */
150 rq->q = q;
320ae51f 151 rq->mq_ctx = ctx;
cc6e3b10 152 req_set_op_attrs(rq, op, op_flags);
af76e555
CH
153 /* do not touch atomic flags, it needs atomic ops against the timer */
154 rq->cpu = -1;
af76e555
CH
155 INIT_HLIST_NODE(&rq->hash);
156 RB_CLEAR_NODE(&rq->rb_node);
af76e555
CH
157 rq->rq_disk = NULL;
158 rq->part = NULL;
3ee32372 159 rq->start_time = jiffies;
af76e555
CH
160#ifdef CONFIG_BLK_CGROUP
161 rq->rl = NULL;
0fec08b4 162 set_start_time_ns(rq);
af76e555
CH
163 rq->io_start_time_ns = 0;
164#endif
165 rq->nr_phys_segments = 0;
166#if defined(CONFIG_BLK_DEV_INTEGRITY)
167 rq->nr_integrity_segments = 0;
168#endif
af76e555
CH
169 rq->special = NULL;
170 /* tag was already set */
171 rq->errors = 0;
af76e555 172
6f4a1626
TB
173 rq->cmd = rq->__cmd;
174
af76e555
CH
175 rq->extra_len = 0;
176 rq->sense_len = 0;
177 rq->resid_len = 0;
178 rq->sense = NULL;
179
af76e555 180 INIT_LIST_HEAD(&rq->timeout_list);
f6be4fb4
JA
181 rq->timeout = 0;
182
af76e555
CH
183 rq->end_io = NULL;
184 rq->end_io_data = NULL;
185 rq->next_rq = NULL;
186
d9d8c5c4 187 ctx->rq_dispatched[rw_is_sync(op, op_flags)]++;
320ae51f
JA
188}
189
5dee8577 190static struct request *
cc6e3b10 191__blk_mq_alloc_request(struct blk_mq_alloc_data *data, int op, int op_flags)
5dee8577
CH
192{
193 struct request *rq;
194 unsigned int tag;
195
cb96a42c 196 tag = blk_mq_get_tag(data);
5dee8577 197 if (tag != BLK_MQ_TAG_FAIL) {
cb96a42c 198 rq = data->hctx->tags->rqs[tag];
5dee8577 199
cb96a42c 200 if (blk_mq_tag_busy(data->hctx)) {
5dee8577 201 rq->cmd_flags = REQ_MQ_INFLIGHT;
cb96a42c 202 atomic_inc(&data->hctx->nr_active);
5dee8577
CH
203 }
204
205 rq->tag = tag;
cc6e3b10 206 blk_mq_rq_ctx_init(data->q, data->ctx, rq, op, op_flags);
5dee8577
CH
207 return rq;
208 }
209
210 return NULL;
211}
212
6f3b0e8b
CH
213struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
214 unsigned int flags)
320ae51f 215{
d852564f
CH
216 struct blk_mq_ctx *ctx;
217 struct blk_mq_hw_ctx *hctx;
320ae51f 218 struct request *rq;
cb96a42c 219 struct blk_mq_alloc_data alloc_data;
a492f075 220 int ret;
320ae51f 221
6f3b0e8b 222 ret = blk_queue_enter(q, flags & BLK_MQ_REQ_NOWAIT);
a492f075
JL
223 if (ret)
224 return ERR_PTR(ret);
320ae51f 225
d852564f 226 ctx = blk_mq_get_ctx(q);
7d7e0f90 227 hctx = blk_mq_map_queue(q, ctx->cpu);
6f3b0e8b 228 blk_mq_set_alloc_data(&alloc_data, q, flags, ctx, hctx);
cc6e3b10 229 rq = __blk_mq_alloc_request(&alloc_data, rw, 0);
d852564f 230 blk_mq_put_ctx(ctx);
841bac2c 231
c76541a9 232 if (!rq) {
3ef28e83 233 blk_queue_exit(q);
a492f075 234 return ERR_PTR(-EWOULDBLOCK);
c76541a9 235 }
0c4de0f3
CH
236
237 rq->__data_len = 0;
238 rq->__sector = (sector_t) -1;
239 rq->bio = rq->biotail = NULL;
320ae51f
JA
240 return rq;
241}
4bb659b1 242EXPORT_SYMBOL(blk_mq_alloc_request);
320ae51f 243
1f5bd336
ML
244struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw,
245 unsigned int flags, unsigned int hctx_idx)
246{
247 struct blk_mq_hw_ctx *hctx;
248 struct blk_mq_ctx *ctx;
249 struct request *rq;
250 struct blk_mq_alloc_data alloc_data;
251 int ret;
252
253 /*
254 * If the tag allocator sleeps we could get an allocation for a
255 * different hardware context. No need to complicate the low level
256 * allocator for this for the rare use case of a command tied to
257 * a specific queue.
258 */
259 if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)))
260 return ERR_PTR(-EINVAL);
261
262 if (hctx_idx >= q->nr_hw_queues)
263 return ERR_PTR(-EIO);
264
265 ret = blk_queue_enter(q, true);
266 if (ret)
267 return ERR_PTR(ret);
268
c8712c6a
CH
269 /*
270 * Check if the hardware context is actually mapped to anything.
271 * If not tell the caller that it should skip this queue.
272 */
1f5bd336 273 hctx = q->queue_hw_ctx[hctx_idx];
c8712c6a
CH
274 if (!blk_mq_hw_queue_mapped(hctx)) {
275 ret = -EXDEV;
276 goto out_queue_exit;
277 }
1f5bd336
ML
278 ctx = __blk_mq_get_ctx(q, cpumask_first(hctx->cpumask));
279
280 blk_mq_set_alloc_data(&alloc_data, q, flags, ctx, hctx);
281 rq = __blk_mq_alloc_request(&alloc_data, rw, 0);
282 if (!rq) {
c8712c6a
CH
283 ret = -EWOULDBLOCK;
284 goto out_queue_exit;
1f5bd336
ML
285 }
286
287 return rq;
c8712c6a
CH
288
289out_queue_exit:
290 blk_queue_exit(q);
291 return ERR_PTR(ret);
1f5bd336
ML
292}
293EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
294
320ae51f
JA
295static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
296 struct blk_mq_ctx *ctx, struct request *rq)
297{
298 const int tag = rq->tag;
299 struct request_queue *q = rq->q;
300
0d2602ca
JA
301 if (rq->cmd_flags & REQ_MQ_INFLIGHT)
302 atomic_dec(&hctx->nr_active);
683d0e12 303 rq->cmd_flags = 0;
0d2602ca 304
af76e555 305 clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
40aabb67 306 blk_mq_put_tag(hctx, ctx, tag);
3ef28e83 307 blk_queue_exit(q);
320ae51f
JA
308}
309
7c7f2f2b 310void blk_mq_free_hctx_request(struct blk_mq_hw_ctx *hctx, struct request *rq)
320ae51f
JA
311{
312 struct blk_mq_ctx *ctx = rq->mq_ctx;
320ae51f
JA
313
314 ctx->rq_completed[rq_is_sync(rq)]++;
320ae51f 315 __blk_mq_free_request(hctx, ctx, rq);
7c7f2f2b
JA
316
317}
318EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request);
319
320void blk_mq_free_request(struct request *rq)
321{
7d7e0f90 322 blk_mq_free_hctx_request(blk_mq_map_queue(rq->q, rq->mq_ctx->cpu), rq);
320ae51f 323}
1a3b595a 324EXPORT_SYMBOL_GPL(blk_mq_free_request);
320ae51f 325
c8a446ad 326inline void __blk_mq_end_request(struct request *rq, int error)
320ae51f 327{
0d11e6ac
ML
328 blk_account_io_done(rq);
329
91b63639 330 if (rq->end_io) {
320ae51f 331 rq->end_io(rq, error);
91b63639
CH
332 } else {
333 if (unlikely(blk_bidi_rq(rq)))
334 blk_mq_free_request(rq->next_rq);
320ae51f 335 blk_mq_free_request(rq);
91b63639 336 }
320ae51f 337}
c8a446ad 338EXPORT_SYMBOL(__blk_mq_end_request);
63151a44 339
c8a446ad 340void blk_mq_end_request(struct request *rq, int error)
63151a44
CH
341{
342 if (blk_update_request(rq, error, blk_rq_bytes(rq)))
343 BUG();
c8a446ad 344 __blk_mq_end_request(rq, error);
63151a44 345}
c8a446ad 346EXPORT_SYMBOL(blk_mq_end_request);
320ae51f 347
30a91cb4 348static void __blk_mq_complete_request_remote(void *data)
320ae51f 349{
3d6efbf6 350 struct request *rq = data;
320ae51f 351
30a91cb4 352 rq->q->softirq_done_fn(rq);
320ae51f 353}
320ae51f 354
ed851860 355static void blk_mq_ipi_complete_request(struct request *rq)
320ae51f
JA
356{
357 struct blk_mq_ctx *ctx = rq->mq_ctx;
38535201 358 bool shared = false;
320ae51f
JA
359 int cpu;
360
38535201 361 if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) {
30a91cb4
CH
362 rq->q->softirq_done_fn(rq);
363 return;
364 }
320ae51f
JA
365
366 cpu = get_cpu();
38535201
CH
367 if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags))
368 shared = cpus_share_cache(cpu, ctx->cpu);
369
370 if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) {
30a91cb4 371 rq->csd.func = __blk_mq_complete_request_remote;
3d6efbf6
CH
372 rq->csd.info = rq;
373 rq->csd.flags = 0;
c46fff2a 374 smp_call_function_single_async(ctx->cpu, &rq->csd);
3d6efbf6 375 } else {
30a91cb4 376 rq->q->softirq_done_fn(rq);
3d6efbf6 377 }
320ae51f
JA
378 put_cpu();
379}
30a91cb4 380
1fa8cc52 381static void __blk_mq_complete_request(struct request *rq)
ed851860
JA
382{
383 struct request_queue *q = rq->q;
384
385 if (!q->softirq_done_fn)
c8a446ad 386 blk_mq_end_request(rq, rq->errors);
ed851860
JA
387 else
388 blk_mq_ipi_complete_request(rq);
389}
390
30a91cb4
CH
391/**
392 * blk_mq_complete_request - end I/O on a request
393 * @rq: the request being processed
394 *
395 * Description:
396 * Ends all I/O on a request. It does not handle partial completions.
397 * The actual completion happens out-of-order, through a IPI handler.
398 **/
f4829a9b 399void blk_mq_complete_request(struct request *rq, int error)
30a91cb4 400{
95f09684
JA
401 struct request_queue *q = rq->q;
402
403 if (unlikely(blk_should_fake_timeout(q)))
30a91cb4 404 return;
f4829a9b
CH
405 if (!blk_mark_rq_complete(rq)) {
406 rq->errors = error;
ed851860 407 __blk_mq_complete_request(rq);
f4829a9b 408 }
30a91cb4
CH
409}
410EXPORT_SYMBOL(blk_mq_complete_request);
320ae51f 411
973c0191
KB
412int blk_mq_request_started(struct request *rq)
413{
414 return test_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
415}
416EXPORT_SYMBOL_GPL(blk_mq_request_started);
417
e2490073 418void blk_mq_start_request(struct request *rq)
320ae51f
JA
419{
420 struct request_queue *q = rq->q;
421
422 trace_block_rq_issue(q, rq);
423
742ee69b 424 rq->resid_len = blk_rq_bytes(rq);
91b63639
CH
425 if (unlikely(blk_bidi_rq(rq)))
426 rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq);
742ee69b 427
2b8393b4 428 blk_add_timer(rq);
87ee7b11 429
538b7534
JA
430 /*
431 * Ensure that ->deadline is visible before set the started
432 * flag and clear the completed flag.
433 */
434 smp_mb__before_atomic();
435
87ee7b11
JA
436 /*
437 * Mark us as started and clear complete. Complete might have been
438 * set if requeue raced with timeout, which then marked it as
439 * complete. So be sure to clear complete again when we start
440 * the request, otherwise we'll ignore the completion event.
441 */
4b570521
JA
442 if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
443 set_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
444 if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags))
445 clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
49f5baa5
CH
446
447 if (q->dma_drain_size && blk_rq_bytes(rq)) {
448 /*
449 * Make sure space for the drain appears. We know we can do
450 * this because max_hw_segments has been adjusted to be one
451 * fewer than the device can handle.
452 */
453 rq->nr_phys_segments++;
454 }
320ae51f 455}
e2490073 456EXPORT_SYMBOL(blk_mq_start_request);
320ae51f 457
ed0791b2 458static void __blk_mq_requeue_request(struct request *rq)
320ae51f
JA
459{
460 struct request_queue *q = rq->q;
461
462 trace_block_rq_requeue(q, rq);
49f5baa5 463
e2490073
CH
464 if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) {
465 if (q->dma_drain_size && blk_rq_bytes(rq))
466 rq->nr_phys_segments--;
467 }
320ae51f
JA
468}
469
ed0791b2
CH
470void blk_mq_requeue_request(struct request *rq)
471{
ed0791b2 472 __blk_mq_requeue_request(rq);
ed0791b2 473
ed0791b2 474 BUG_ON(blk_queued_rq(rq));
6fca6a61 475 blk_mq_add_to_requeue_list(rq, true);
ed0791b2
CH
476}
477EXPORT_SYMBOL(blk_mq_requeue_request);
478
6fca6a61
CH
479static void blk_mq_requeue_work(struct work_struct *work)
480{
481 struct request_queue *q =
2849450a 482 container_of(work, struct request_queue, requeue_work.work);
6fca6a61
CH
483 LIST_HEAD(rq_list);
484 struct request *rq, *next;
485 unsigned long flags;
486
487 spin_lock_irqsave(&q->requeue_lock, flags);
488 list_splice_init(&q->requeue_list, &rq_list);
489 spin_unlock_irqrestore(&q->requeue_lock, flags);
490
491 list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
492 if (!(rq->cmd_flags & REQ_SOFTBARRIER))
493 continue;
494
495 rq->cmd_flags &= ~REQ_SOFTBARRIER;
496 list_del_init(&rq->queuelist);
497 blk_mq_insert_request(rq, true, false, false);
498 }
499
500 while (!list_empty(&rq_list)) {
501 rq = list_entry(rq_list.next, struct request, queuelist);
502 list_del_init(&rq->queuelist);
503 blk_mq_insert_request(rq, false, false, false);
504 }
505
8b957415
JA
506 /*
507 * Use the start variant of queue running here, so that running
508 * the requeue work will kick stopped queues.
509 */
510 blk_mq_start_hw_queues(q);
6fca6a61
CH
511}
512
513void blk_mq_add_to_requeue_list(struct request *rq, bool at_head)
514{
515 struct request_queue *q = rq->q;
516 unsigned long flags;
517
518 /*
519 * We abuse this flag that is otherwise used by the I/O scheduler to
520 * request head insertation from the workqueue.
521 */
522 BUG_ON(rq->cmd_flags & REQ_SOFTBARRIER);
523
524 spin_lock_irqsave(&q->requeue_lock, flags);
525 if (at_head) {
526 rq->cmd_flags |= REQ_SOFTBARRIER;
527 list_add(&rq->queuelist, &q->requeue_list);
528 } else {
529 list_add_tail(&rq->queuelist, &q->requeue_list);
530 }
531 spin_unlock_irqrestore(&q->requeue_lock, flags);
532}
533EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
534
c68ed59f
KB
535void blk_mq_cancel_requeue_work(struct request_queue *q)
536{
2849450a 537 cancel_delayed_work_sync(&q->requeue_work);
c68ed59f
KB
538}
539EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work);
540
6fca6a61
CH
541void blk_mq_kick_requeue_list(struct request_queue *q)
542{
2849450a 543 kblockd_schedule_delayed_work(&q->requeue_work, 0);
6fca6a61
CH
544}
545EXPORT_SYMBOL(blk_mq_kick_requeue_list);
546
2849450a
MS
547void blk_mq_delay_kick_requeue_list(struct request_queue *q,
548 unsigned long msecs)
549{
550 kblockd_schedule_delayed_work(&q->requeue_work,
551 msecs_to_jiffies(msecs));
552}
553EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
554
1885b24d
JA
555void blk_mq_abort_requeue_list(struct request_queue *q)
556{
557 unsigned long flags;
558 LIST_HEAD(rq_list);
559
560 spin_lock_irqsave(&q->requeue_lock, flags);
561 list_splice_init(&q->requeue_list, &rq_list);
562 spin_unlock_irqrestore(&q->requeue_lock, flags);
563
564 while (!list_empty(&rq_list)) {
565 struct request *rq;
566
567 rq = list_first_entry(&rq_list, struct request, queuelist);
568 list_del_init(&rq->queuelist);
569 rq->errors = -EIO;
570 blk_mq_end_request(rq, rq->errors);
571 }
572}
573EXPORT_SYMBOL(blk_mq_abort_requeue_list);
574
0e62f51f
JA
575struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
576{
88c7b2b7
JA
577 if (tag < tags->nr_tags) {
578 prefetch(tags->rqs[tag]);
4ee86bab 579 return tags->rqs[tag];
88c7b2b7 580 }
4ee86bab
HR
581
582 return NULL;
24d2f903
CH
583}
584EXPORT_SYMBOL(blk_mq_tag_to_rq);
585
320ae51f 586struct blk_mq_timeout_data {
46f92d42
CH
587 unsigned long next;
588 unsigned int next_set;
320ae51f
JA
589};
590
90415837 591void blk_mq_rq_timed_out(struct request *req, bool reserved)
320ae51f 592{
46f92d42
CH
593 struct blk_mq_ops *ops = req->q->mq_ops;
594 enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
87ee7b11
JA
595
596 /*
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.
604 */
46f92d42
CH
605 if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags))
606 return;
87ee7b11 607
46f92d42 608 if (ops->timeout)
0152fb6b 609 ret = ops->timeout(req, reserved);
46f92d42
CH
610
611 switch (ret) {
612 case BLK_EH_HANDLED:
613 __blk_mq_complete_request(req);
614 break;
615 case BLK_EH_RESET_TIMER:
616 blk_add_timer(req);
617 blk_clear_rq_complete(req);
618 break;
619 case BLK_EH_NOT_HANDLED:
620 break;
621 default:
622 printk(KERN_ERR "block: bad eh return: %d\n", ret);
623 break;
624 }
87ee7b11 625}
5b3f25fc 626
81481eb4
CH
627static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
628 struct request *rq, void *priv, bool reserved)
629{
630 struct blk_mq_timeout_data *data = priv;
87ee7b11 631
eb130dbf
KB
632 if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) {
633 /*
634 * If a request wasn't started before the queue was
635 * marked dying, kill it here or it'll go unnoticed.
636 */
a59e0f57
KB
637 if (unlikely(blk_queue_dying(rq->q))) {
638 rq->errors = -EIO;
639 blk_mq_end_request(rq, rq->errors);
640 }
46f92d42 641 return;
eb130dbf 642 }
87ee7b11 643
46f92d42
CH
644 if (time_after_eq(jiffies, rq->deadline)) {
645 if (!blk_mark_rq_complete(rq))
0152fb6b 646 blk_mq_rq_timed_out(rq, reserved);
46f92d42
CH
647 } else if (!data->next_set || time_after(data->next, rq->deadline)) {
648 data->next = rq->deadline;
649 data->next_set = 1;
650 }
87ee7b11
JA
651}
652
287922eb 653static void blk_mq_timeout_work(struct work_struct *work)
320ae51f 654{
287922eb
CH
655 struct request_queue *q =
656 container_of(work, struct request_queue, timeout_work);
81481eb4
CH
657 struct blk_mq_timeout_data data = {
658 .next = 0,
659 .next_set = 0,
660 };
81481eb4 661 int i;
320ae51f 662
71f79fb3
GKB
663 /* A deadlock might occur if a request is stuck requiring a
664 * timeout at the same time a queue freeze is waiting
665 * completion, since the timeout code would not be able to
666 * acquire the queue reference here.
667 *
668 * That's why we don't use blk_queue_enter here; instead, we use
669 * percpu_ref_tryget directly, because we need to be able to
670 * obtain a reference even in the short window between the queue
671 * starting to freeze, by dropping the first reference in
672 * blk_mq_freeze_queue_start, and the moment the last request is
673 * consumed, marked by the instant q_usage_counter reaches
674 * zero.
675 */
676 if (!percpu_ref_tryget(&q->q_usage_counter))
287922eb
CH
677 return;
678
0bf6cd5b 679 blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data);
320ae51f 680
81481eb4
CH
681 if (data.next_set) {
682 data.next = blk_rq_timeout(round_jiffies_up(data.next));
683 mod_timer(&q->timeout, data.next);
0d2602ca 684 } else {
0bf6cd5b
CH
685 struct blk_mq_hw_ctx *hctx;
686
f054b56c
ML
687 queue_for_each_hw_ctx(q, hctx, i) {
688 /* the hctx may be unmapped, so check it here */
689 if (blk_mq_hw_queue_mapped(hctx))
690 blk_mq_tag_idle(hctx);
691 }
0d2602ca 692 }
287922eb 693 blk_queue_exit(q);
320ae51f
JA
694}
695
696/*
697 * Reverse check our software queue for entries that we could potentially
698 * merge with. Currently includes a hand-wavy stop count of 8, to not spend
699 * too much time checking for merges.
700 */
701static bool blk_mq_attempt_merge(struct request_queue *q,
702 struct blk_mq_ctx *ctx, struct bio *bio)
703{
704 struct request *rq;
705 int checked = 8;
706
707 list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
708 int el_ret;
709
710 if (!checked--)
711 break;
712
713 if (!blk_rq_merge_ok(rq, bio))
714 continue;
715
716 el_ret = blk_try_merge(rq, bio);
717 if (el_ret == ELEVATOR_BACK_MERGE) {
718 if (bio_attempt_back_merge(q, rq, bio)) {
719 ctx->rq_merged++;
720 return true;
721 }
722 break;
723 } else if (el_ret == ELEVATOR_FRONT_MERGE) {
724 if (bio_attempt_front_merge(q, rq, bio)) {
725 ctx->rq_merged++;
726 return true;
727 }
728 break;
729 }
730 }
731
732 return false;
733}
734
88459642
OS
735struct flush_busy_ctx_data {
736 struct blk_mq_hw_ctx *hctx;
737 struct list_head *list;
738};
739
740static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
741{
742 struct flush_busy_ctx_data *flush_data = data;
743 struct blk_mq_hw_ctx *hctx = flush_data->hctx;
744 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
745
746 sbitmap_clear_bit(sb, bitnr);
747 spin_lock(&ctx->lock);
748 list_splice_tail_init(&ctx->rq_list, flush_data->list);
749 spin_unlock(&ctx->lock);
750 return true;
751}
752
1429d7c9
JA
753/*
754 * Process software queues that have been marked busy, splicing them
755 * to the for-dispatch
756 */
757static void flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
758{
88459642
OS
759 struct flush_busy_ctx_data data = {
760 .hctx = hctx,
761 .list = list,
762 };
1429d7c9 763
88459642 764 sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
1429d7c9 765}
1429d7c9 766
703fd1c0
JA
767static inline unsigned int queued_to_index(unsigned int queued)
768{
769 if (!queued)
770 return 0;
1429d7c9 771
703fd1c0 772 return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
1429d7c9
JA
773}
774
320ae51f
JA
775/*
776 * Run this hardware queue, pulling any software queues mapped to it in.
777 * Note that this function currently has various problems around ordering
778 * of IO. In particular, we'd like FIFO behaviour on handling existing
779 * items on the hctx->dispatch list. Ignore that for now.
780 */
781static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
782{
783 struct request_queue *q = hctx->queue;
320ae51f
JA
784 struct request *rq;
785 LIST_HEAD(rq_list);
74c45052
JA
786 LIST_HEAD(driver_list);
787 struct list_head *dptr;
1429d7c9 788 int queued;
320ae51f 789
5d12f905 790 if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state)))
320ae51f
JA
791 return;
792
0e87e58b
JA
793 WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
794 cpu_online(hctx->next_cpu));
795
320ae51f
JA
796 hctx->run++;
797
798 /*
799 * Touch any software queue that has pending entries.
800 */
1429d7c9 801 flush_busy_ctxs(hctx, &rq_list);
320ae51f
JA
802
803 /*
804 * If we have previous entries on our dispatch list, grab them
805 * and stuff them at the front for more fair dispatch.
806 */
807 if (!list_empty_careful(&hctx->dispatch)) {
808 spin_lock(&hctx->lock);
809 if (!list_empty(&hctx->dispatch))
810 list_splice_init(&hctx->dispatch, &rq_list);
811 spin_unlock(&hctx->lock);
812 }
813
74c45052
JA
814 /*
815 * Start off with dptr being NULL, so we start the first request
816 * immediately, even if we have more pending.
817 */
818 dptr = NULL;
819
320ae51f
JA
820 /*
821 * Now process all the entries, sending them to the driver.
822 */
1429d7c9 823 queued = 0;
320ae51f 824 while (!list_empty(&rq_list)) {
74c45052 825 struct blk_mq_queue_data bd;
320ae51f
JA
826 int ret;
827
828 rq = list_first_entry(&rq_list, struct request, queuelist);
829 list_del_init(&rq->queuelist);
320ae51f 830
74c45052
JA
831 bd.rq = rq;
832 bd.list = dptr;
833 bd.last = list_empty(&rq_list);
834
835 ret = q->mq_ops->queue_rq(hctx, &bd);
320ae51f
JA
836 switch (ret) {
837 case BLK_MQ_RQ_QUEUE_OK:
838 queued++;
52b9c330 839 break;
320ae51f 840 case BLK_MQ_RQ_QUEUE_BUSY:
320ae51f 841 list_add(&rq->queuelist, &rq_list);
ed0791b2 842 __blk_mq_requeue_request(rq);
320ae51f
JA
843 break;
844 default:
845 pr_err("blk-mq: bad return on queue: %d\n", ret);
320ae51f 846 case BLK_MQ_RQ_QUEUE_ERROR:
1e93b8c2 847 rq->errors = -EIO;
c8a446ad 848 blk_mq_end_request(rq, rq->errors);
320ae51f
JA
849 break;
850 }
851
852 if (ret == BLK_MQ_RQ_QUEUE_BUSY)
853 break;
74c45052
JA
854
855 /*
856 * We've done the first request. If we have more than 1
857 * left in the list, set dptr to defer issue.
858 */
859 if (!dptr && rq_list.next != rq_list.prev)
860 dptr = &driver_list;
320ae51f
JA
861 }
862
703fd1c0 863 hctx->dispatched[queued_to_index(queued)]++;
320ae51f
JA
864
865 /*
866 * Any items that need requeuing? Stuff them into hctx->dispatch,
867 * that is where we will continue on next queue run.
868 */
869 if (!list_empty(&rq_list)) {
870 spin_lock(&hctx->lock);
871 list_splice(&rq_list, &hctx->dispatch);
872 spin_unlock(&hctx->lock);
9ba52e58
SL
873 /*
874 * the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but
875 * it's possible the queue is stopped and restarted again
876 * before this. Queue restart will dispatch requests. And since
877 * requests in rq_list aren't added into hctx->dispatch yet,
878 * the requests in rq_list might get lost.
879 *
880 * blk_mq_run_hw_queue() already checks the STOPPED bit
881 **/
882 blk_mq_run_hw_queue(hctx, true);
320ae51f
JA
883 }
884}
885
506e931f
JA
886/*
887 * It'd be great if the workqueue API had a way to pass
888 * in a mask and had some smarts for more clever placement.
889 * For now we just round-robin here, switching for every
890 * BLK_MQ_CPU_WORK_BATCH queued items.
891 */
892static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
893{
b657d7e6
CH
894 if (hctx->queue->nr_hw_queues == 1)
895 return WORK_CPU_UNBOUND;
506e931f
JA
896
897 if (--hctx->next_cpu_batch <= 0) {
b657d7e6 898 int cpu = hctx->next_cpu, next_cpu;
506e931f
JA
899
900 next_cpu = cpumask_next(hctx->next_cpu, hctx->cpumask);
901 if (next_cpu >= nr_cpu_ids)
902 next_cpu = cpumask_first(hctx->cpumask);
903
904 hctx->next_cpu = next_cpu;
905 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
b657d7e6
CH
906
907 return cpu;
506e931f
JA
908 }
909
b657d7e6 910 return hctx->next_cpu;
506e931f
JA
911}
912
320ae51f
JA
913void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
914{
19c66e59
ML
915 if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state) ||
916 !blk_mq_hw_queue_mapped(hctx)))
320ae51f
JA
917 return;
918
1b792f2f 919 if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
2a90d4aa
PB
920 int cpu = get_cpu();
921 if (cpumask_test_cpu(cpu, hctx->cpumask)) {
398205b8 922 __blk_mq_run_hw_queue(hctx);
2a90d4aa 923 put_cpu();
398205b8
PB
924 return;
925 }
e4043dcf 926
2a90d4aa 927 put_cpu();
e4043dcf 928 }
398205b8 929
27489a3c 930 kblockd_schedule_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work);
320ae51f
JA
931}
932
b94ec296 933void blk_mq_run_hw_queues(struct request_queue *q, bool async)
320ae51f
JA
934{
935 struct blk_mq_hw_ctx *hctx;
936 int i;
937
938 queue_for_each_hw_ctx(q, hctx, i) {
939 if ((!blk_mq_hctx_has_pending(hctx) &&
940 list_empty_careful(&hctx->dispatch)) ||
5d12f905 941 test_bit(BLK_MQ_S_STOPPED, &hctx->state))
320ae51f
JA
942 continue;
943
b94ec296 944 blk_mq_run_hw_queue(hctx, async);
320ae51f
JA
945 }
946}
b94ec296 947EXPORT_SYMBOL(blk_mq_run_hw_queues);
320ae51f
JA
948
949void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
950{
27489a3c 951 cancel_work(&hctx->run_work);
70f4db63 952 cancel_delayed_work(&hctx->delay_work);
320ae51f
JA
953 set_bit(BLK_MQ_S_STOPPED, &hctx->state);
954}
955EXPORT_SYMBOL(blk_mq_stop_hw_queue);
956
280d45f6
CH
957void blk_mq_stop_hw_queues(struct request_queue *q)
958{
959 struct blk_mq_hw_ctx *hctx;
960 int i;
961
962 queue_for_each_hw_ctx(q, hctx, i)
963 blk_mq_stop_hw_queue(hctx);
964}
965EXPORT_SYMBOL(blk_mq_stop_hw_queues);
966
320ae51f
JA
967void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
968{
969 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
e4043dcf 970
0ffbce80 971 blk_mq_run_hw_queue(hctx, false);
320ae51f
JA
972}
973EXPORT_SYMBOL(blk_mq_start_hw_queue);
974
2f268556
CH
975void blk_mq_start_hw_queues(struct request_queue *q)
976{
977 struct blk_mq_hw_ctx *hctx;
978 int i;
979
980 queue_for_each_hw_ctx(q, hctx, i)
981 blk_mq_start_hw_queue(hctx);
982}
983EXPORT_SYMBOL(blk_mq_start_hw_queues);
984
1b4a3258 985void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
320ae51f
JA
986{
987 struct blk_mq_hw_ctx *hctx;
988 int i;
989
990 queue_for_each_hw_ctx(q, hctx, i) {
991 if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state))
992 continue;
993
994 clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
1b4a3258 995 blk_mq_run_hw_queue(hctx, async);
320ae51f
JA
996 }
997}
998EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
999
70f4db63 1000static void blk_mq_run_work_fn(struct work_struct *work)
320ae51f
JA
1001{
1002 struct blk_mq_hw_ctx *hctx;
1003
27489a3c 1004 hctx = container_of(work, struct blk_mq_hw_ctx, run_work);
e4043dcf 1005
320ae51f
JA
1006 __blk_mq_run_hw_queue(hctx);
1007}
1008
70f4db63
CH
1009static void blk_mq_delay_work_fn(struct work_struct *work)
1010{
1011 struct blk_mq_hw_ctx *hctx;
1012
1013 hctx = container_of(work, struct blk_mq_hw_ctx, delay_work.work);
1014
1015 if (test_and_clear_bit(BLK_MQ_S_STOPPED, &hctx->state))
1016 __blk_mq_run_hw_queue(hctx);
1017}
1018
1019void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
1020{
19c66e59
ML
1021 if (unlikely(!blk_mq_hw_queue_mapped(hctx)))
1022 return;
70f4db63 1023
b657d7e6
CH
1024 kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
1025 &hctx->delay_work, msecs_to_jiffies(msecs));
70f4db63
CH
1026}
1027EXPORT_SYMBOL(blk_mq_delay_queue);
1028
cfd0c552 1029static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
cfd0c552
ML
1030 struct request *rq,
1031 bool at_head)
320ae51f 1032{
e57690fe
JA
1033 struct blk_mq_ctx *ctx = rq->mq_ctx;
1034
01b983c9
JA
1035 trace_block_rq_insert(hctx->queue, rq);
1036
72a0a36e
CH
1037 if (at_head)
1038 list_add(&rq->queuelist, &ctx->rq_list);
1039 else
1040 list_add_tail(&rq->queuelist, &ctx->rq_list);
cfd0c552 1041}
4bb659b1 1042
cfd0c552
ML
1043static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx,
1044 struct request *rq, bool at_head)
1045{
1046 struct blk_mq_ctx *ctx = rq->mq_ctx;
1047
e57690fe 1048 __blk_mq_insert_req_list(hctx, rq, at_head);
320ae51f 1049 blk_mq_hctx_mark_pending(hctx, ctx);
320ae51f
JA
1050}
1051
eeabc850 1052void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue,
e57690fe 1053 bool async)
320ae51f 1054{
e57690fe 1055 struct blk_mq_ctx *ctx = rq->mq_ctx;
eeabc850 1056 struct request_queue *q = rq->q;
7d7e0f90 1057 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
320ae51f 1058
a57a178a
CH
1059 spin_lock(&ctx->lock);
1060 __blk_mq_insert_request(hctx, rq, at_head);
1061 spin_unlock(&ctx->lock);
320ae51f 1062
320ae51f
JA
1063 if (run_queue)
1064 blk_mq_run_hw_queue(hctx, async);
1065}
1066
1067static void blk_mq_insert_requests(struct request_queue *q,
1068 struct blk_mq_ctx *ctx,
1069 struct list_head *list,
1070 int depth,
1071 bool from_schedule)
1072
1073{
7d7e0f90 1074 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
320ae51f
JA
1075
1076 trace_block_unplug(q, depth, !from_schedule);
1077
320ae51f
JA
1078 /*
1079 * preemption doesn't flush plug list, so it's possible ctx->cpu is
1080 * offline now
1081 */
1082 spin_lock(&ctx->lock);
1083 while (!list_empty(list)) {
1084 struct request *rq;
1085
1086 rq = list_first_entry(list, struct request, queuelist);
e57690fe 1087 BUG_ON(rq->mq_ctx != ctx);
320ae51f 1088 list_del_init(&rq->queuelist);
e57690fe 1089 __blk_mq_insert_req_list(hctx, rq, false);
320ae51f 1090 }
cfd0c552 1091 blk_mq_hctx_mark_pending(hctx, ctx);
320ae51f
JA
1092 spin_unlock(&ctx->lock);
1093
320ae51f
JA
1094 blk_mq_run_hw_queue(hctx, from_schedule);
1095}
1096
1097static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b)
1098{
1099 struct request *rqa = container_of(a, struct request, queuelist);
1100 struct request *rqb = container_of(b, struct request, queuelist);
1101
1102 return !(rqa->mq_ctx < rqb->mq_ctx ||
1103 (rqa->mq_ctx == rqb->mq_ctx &&
1104 blk_rq_pos(rqa) < blk_rq_pos(rqb)));
1105}
1106
1107void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
1108{
1109 struct blk_mq_ctx *this_ctx;
1110 struct request_queue *this_q;
1111 struct request *rq;
1112 LIST_HEAD(list);
1113 LIST_HEAD(ctx_list);
1114 unsigned int depth;
1115
1116 list_splice_init(&plug->mq_list, &list);
1117
1118 list_sort(NULL, &list, plug_ctx_cmp);
1119
1120 this_q = NULL;
1121 this_ctx = NULL;
1122 depth = 0;
1123
1124 while (!list_empty(&list)) {
1125 rq = list_entry_rq(list.next);
1126 list_del_init(&rq->queuelist);
1127 BUG_ON(!rq->q);
1128 if (rq->mq_ctx != this_ctx) {
1129 if (this_ctx) {
1130 blk_mq_insert_requests(this_q, this_ctx,
1131 &ctx_list, depth,
1132 from_schedule);
1133 }
1134
1135 this_ctx = rq->mq_ctx;
1136 this_q = rq->q;
1137 depth = 0;
1138 }
1139
1140 depth++;
1141 list_add_tail(&rq->queuelist, &ctx_list);
1142 }
1143
1144 /*
1145 * If 'this_ctx' is set, we know we have entries to complete
1146 * on 'ctx_list'. Do those.
1147 */
1148 if (this_ctx) {
1149 blk_mq_insert_requests(this_q, this_ctx, &ctx_list, depth,
1150 from_schedule);
1151 }
1152}
1153
1154static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
1155{
1156 init_request_from_bio(rq, bio);
4b570521 1157
a21f2a3e 1158 blk_account_io_start(rq, 1);
320ae51f
JA
1159}
1160
274a5843
JA
1161static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx)
1162{
1163 return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
1164 !blk_queue_nomerges(hctx->queue);
1165}
1166
07068d5b
JA
1167static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx,
1168 struct blk_mq_ctx *ctx,
1169 struct request *rq, struct bio *bio)
320ae51f 1170{
e18378a6 1171 if (!hctx_allow_merges(hctx) || !bio_mergeable(bio)) {
07068d5b
JA
1172 blk_mq_bio_to_request(rq, bio);
1173 spin_lock(&ctx->lock);
1174insert_rq:
1175 __blk_mq_insert_request(hctx, rq, false);
1176 spin_unlock(&ctx->lock);
1177 return false;
1178 } else {
274a5843
JA
1179 struct request_queue *q = hctx->queue;
1180
07068d5b
JA
1181 spin_lock(&ctx->lock);
1182 if (!blk_mq_attempt_merge(q, ctx, bio)) {
1183 blk_mq_bio_to_request(rq, bio);
1184 goto insert_rq;
1185 }
320ae51f 1186
07068d5b
JA
1187 spin_unlock(&ctx->lock);
1188 __blk_mq_free_request(hctx, ctx, rq);
1189 return true;
14ec77f3 1190 }
07068d5b 1191}
14ec77f3 1192
07068d5b
JA
1193struct blk_map_ctx {
1194 struct blk_mq_hw_ctx *hctx;
1195 struct blk_mq_ctx *ctx;
1196};
1197
1198static struct request *blk_mq_map_request(struct request_queue *q,
1199 struct bio *bio,
1200 struct blk_map_ctx *data)
1201{
1202 struct blk_mq_hw_ctx *hctx;
1203 struct blk_mq_ctx *ctx;
1204 struct request *rq;
cc6e3b10
MC
1205 int op = bio_data_dir(bio);
1206 int op_flags = 0;
cb96a42c 1207 struct blk_mq_alloc_data alloc_data;
320ae51f 1208
3ef28e83 1209 blk_queue_enter_live(q);
320ae51f 1210 ctx = blk_mq_get_ctx(q);
7d7e0f90 1211 hctx = blk_mq_map_queue(q, ctx->cpu);
320ae51f 1212
1eff9d32 1213 if (rw_is_sync(bio_op(bio), bio->bi_opf))
cc6e3b10 1214 op_flags |= REQ_SYNC;
07068d5b 1215
cc6e3b10 1216 trace_block_getrq(q, bio, op);
63581af3 1217 blk_mq_set_alloc_data(&alloc_data, q, 0, ctx, hctx);
cc6e3b10 1218 rq = __blk_mq_alloc_request(&alloc_data, op, op_flags);
320ae51f
JA
1219
1220 hctx->queued++;
07068d5b
JA
1221 data->hctx = hctx;
1222 data->ctx = ctx;
1223 return rq;
1224}
1225
7b371636 1226static int blk_mq_direct_issue_request(struct request *rq, blk_qc_t *cookie)
f984df1f
SL
1227{
1228 int ret;
1229 struct request_queue *q = rq->q;
7d7e0f90 1230 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, rq->mq_ctx->cpu);
f984df1f
SL
1231 struct blk_mq_queue_data bd = {
1232 .rq = rq,
1233 .list = NULL,
1234 .last = 1
1235 };
7b371636 1236 blk_qc_t new_cookie = blk_tag_to_qc_t(rq->tag, hctx->queue_num);
f984df1f
SL
1237
1238 /*
1239 * For OK queue, we are done. For error, kill it. Any other
1240 * error (busy), just add it to our list as we previously
1241 * would have done
1242 */
1243 ret = q->mq_ops->queue_rq(hctx, &bd);
7b371636
JA
1244 if (ret == BLK_MQ_RQ_QUEUE_OK) {
1245 *cookie = new_cookie;
f984df1f 1246 return 0;
7b371636 1247 }
f984df1f 1248
7b371636
JA
1249 __blk_mq_requeue_request(rq);
1250
1251 if (ret == BLK_MQ_RQ_QUEUE_ERROR) {
1252 *cookie = BLK_QC_T_NONE;
1253 rq->errors = -EIO;
1254 blk_mq_end_request(rq, rq->errors);
1255 return 0;
f984df1f 1256 }
7b371636
JA
1257
1258 return -1;
f984df1f
SL
1259}
1260
07068d5b
JA
1261/*
1262 * Multiple hardware queue variant. This will not use per-process plugs,
1263 * but will attempt to bypass the hctx queueing if we can go straight to
1264 * hardware for SYNC IO.
1265 */
dece1635 1266static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
07068d5b 1267{
1eff9d32
JA
1268 const int is_sync = rw_is_sync(bio_op(bio), bio->bi_opf);
1269 const int is_flush_fua = bio->bi_opf & (REQ_PREFLUSH | REQ_FUA);
07068d5b
JA
1270 struct blk_map_ctx data;
1271 struct request *rq;
f984df1f
SL
1272 unsigned int request_count = 0;
1273 struct blk_plug *plug;
5b3f341f 1274 struct request *same_queue_rq = NULL;
7b371636 1275 blk_qc_t cookie;
07068d5b
JA
1276
1277 blk_queue_bounce(q, &bio);
1278
1279 if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
4246a0b6 1280 bio_io_error(bio);
dece1635 1281 return BLK_QC_T_NONE;
07068d5b
JA
1282 }
1283
54efd50b
KO
1284 blk_queue_split(q, &bio, q->bio_split);
1285
87c279e6
OS
1286 if (!is_flush_fua && !blk_queue_nomerges(q) &&
1287 blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
1288 return BLK_QC_T_NONE;
f984df1f 1289
07068d5b
JA
1290 rq = blk_mq_map_request(q, bio, &data);
1291 if (unlikely(!rq))
dece1635 1292 return BLK_QC_T_NONE;
07068d5b 1293
7b371636 1294 cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
07068d5b
JA
1295
1296 if (unlikely(is_flush_fua)) {
1297 blk_mq_bio_to_request(rq, bio);
1298 blk_insert_flush(rq);
1299 goto run_queue;
1300 }
1301
f984df1f 1302 plug = current->plug;
e167dfb5
JA
1303 /*
1304 * If the driver supports defer issued based on 'last', then
1305 * queue it up like normal since we can potentially save some
1306 * CPU this way.
1307 */
f984df1f
SL
1308 if (((plug && !blk_queue_nomerges(q)) || is_sync) &&
1309 !(data.hctx->flags & BLK_MQ_F_DEFER_ISSUE)) {
1310 struct request *old_rq = NULL;
07068d5b
JA
1311
1312 blk_mq_bio_to_request(rq, bio);
07068d5b
JA
1313
1314 /*
b094f89c 1315 * We do limited pluging. If the bio can be merged, do that.
f984df1f
SL
1316 * Otherwise the existing request in the plug list will be
1317 * issued. So the plug list will have one request at most
07068d5b 1318 */
f984df1f 1319 if (plug) {
5b3f341f
SL
1320 /*
1321 * The plug list might get flushed before this. If that
b094f89c
JA
1322 * happens, same_queue_rq is invalid and plug list is
1323 * empty
1324 */
5b3f341f
SL
1325 if (same_queue_rq && !list_empty(&plug->mq_list)) {
1326 old_rq = same_queue_rq;
f984df1f 1327 list_del_init(&old_rq->queuelist);
07068d5b 1328 }
f984df1f
SL
1329 list_add_tail(&rq->queuelist, &plug->mq_list);
1330 } else /* is_sync */
1331 old_rq = rq;
1332 blk_mq_put_ctx(data.ctx);
1333 if (!old_rq)
7b371636
JA
1334 goto done;
1335 if (!blk_mq_direct_issue_request(old_rq, &cookie))
1336 goto done;
f984df1f 1337 blk_mq_insert_request(old_rq, false, true, true);
7b371636 1338 goto done;
07068d5b
JA
1339 }
1340
1341 if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
1342 /*
1343 * For a SYNC request, send it to the hardware immediately. For
1344 * an ASYNC request, just ensure that we run it later on. The
1345 * latter allows for merging opportunities and more efficient
1346 * dispatching.
1347 */
1348run_queue:
1349 blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
1350 }
07068d5b 1351 blk_mq_put_ctx(data.ctx);
7b371636
JA
1352done:
1353 return cookie;
07068d5b
JA
1354}
1355
1356/*
1357 * Single hardware queue variant. This will attempt to use any per-process
1358 * plug for merging and IO deferral.
1359 */
dece1635 1360static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
07068d5b 1361{
1eff9d32
JA
1362 const int is_sync = rw_is_sync(bio_op(bio), bio->bi_opf);
1363 const int is_flush_fua = bio->bi_opf & (REQ_PREFLUSH | REQ_FUA);
e6c4438b
JM
1364 struct blk_plug *plug;
1365 unsigned int request_count = 0;
07068d5b
JA
1366 struct blk_map_ctx data;
1367 struct request *rq;
7b371636 1368 blk_qc_t cookie;
07068d5b 1369
07068d5b
JA
1370 blk_queue_bounce(q, &bio);
1371
1372 if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
4246a0b6 1373 bio_io_error(bio);
dece1635 1374 return BLK_QC_T_NONE;
07068d5b
JA
1375 }
1376
54efd50b
KO
1377 blk_queue_split(q, &bio, q->bio_split);
1378
87c279e6
OS
1379 if (!is_flush_fua && !blk_queue_nomerges(q)) {
1380 if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
1381 return BLK_QC_T_NONE;
1382 } else
1383 request_count = blk_plug_queued_count(q);
07068d5b
JA
1384
1385 rq = blk_mq_map_request(q, bio, &data);
ff87bcec 1386 if (unlikely(!rq))
dece1635 1387 return BLK_QC_T_NONE;
320ae51f 1388
7b371636 1389 cookie = blk_tag_to_qc_t(rq->tag, data.hctx->queue_num);
320ae51f
JA
1390
1391 if (unlikely(is_flush_fua)) {
1392 blk_mq_bio_to_request(rq, bio);
320ae51f
JA
1393 blk_insert_flush(rq);
1394 goto run_queue;
1395 }
1396
1397 /*
1398 * A task plug currently exists. Since this is completely lockless,
1399 * utilize that to temporarily store requests until the task is
1400 * either done or scheduled away.
1401 */
e6c4438b
JM
1402 plug = current->plug;
1403 if (plug) {
1404 blk_mq_bio_to_request(rq, bio);
676d0607 1405 if (!request_count)
e6c4438b 1406 trace_block_plug(q);
b094f89c
JA
1407
1408 blk_mq_put_ctx(data.ctx);
1409
1410 if (request_count >= BLK_MAX_REQUEST_COUNT) {
e6c4438b
JM
1411 blk_flush_plug_list(plug, false);
1412 trace_block_plug(q);
320ae51f 1413 }
b094f89c 1414
e6c4438b 1415 list_add_tail(&rq->queuelist, &plug->mq_list);
7b371636 1416 return cookie;
320ae51f
JA
1417 }
1418
07068d5b
JA
1419 if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
1420 /*
1421 * For a SYNC request, send it to the hardware immediately. For
1422 * an ASYNC request, just ensure that we run it later on. The
1423 * latter allows for merging opportunities and more efficient
1424 * dispatching.
1425 */
1426run_queue:
1427 blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
320ae51f
JA
1428 }
1429
07068d5b 1430 blk_mq_put_ctx(data.ctx);
7b371636 1431 return cookie;
320ae51f
JA
1432}
1433
24d2f903
CH
1434static void blk_mq_free_rq_map(struct blk_mq_tag_set *set,
1435 struct blk_mq_tags *tags, unsigned int hctx_idx)
95363efd 1436{
e9b267d9 1437 struct page *page;
320ae51f 1438
24d2f903 1439 if (tags->rqs && set->ops->exit_request) {
e9b267d9 1440 int i;
320ae51f 1441
24d2f903
CH
1442 for (i = 0; i < tags->nr_tags; i++) {
1443 if (!tags->rqs[i])
e9b267d9 1444 continue;
24d2f903
CH
1445 set->ops->exit_request(set->driver_data, tags->rqs[i],
1446 hctx_idx, i);
a5164405 1447 tags->rqs[i] = NULL;
e9b267d9 1448 }
320ae51f 1449 }
320ae51f 1450
24d2f903
CH
1451 while (!list_empty(&tags->page_list)) {
1452 page = list_first_entry(&tags->page_list, struct page, lru);
6753471c 1453 list_del_init(&page->lru);
f75782e4
CM
1454 /*
1455 * Remove kmemleak object previously allocated in
1456 * blk_mq_init_rq_map().
1457 */
1458 kmemleak_free(page_address(page));
320ae51f
JA
1459 __free_pages(page, page->private);
1460 }
1461
24d2f903 1462 kfree(tags->rqs);
320ae51f 1463
24d2f903 1464 blk_mq_free_tags(tags);
320ae51f
JA
1465}
1466
1467static size_t order_to_size(unsigned int order)
1468{
4ca08500 1469 return (size_t)PAGE_SIZE << order;
320ae51f
JA
1470}
1471
24d2f903
CH
1472static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set,
1473 unsigned int hctx_idx)
320ae51f 1474{
24d2f903 1475 struct blk_mq_tags *tags;
320ae51f
JA
1476 unsigned int i, j, entries_per_page, max_order = 4;
1477 size_t rq_size, left;
1478
24d2f903 1479 tags = blk_mq_init_tags(set->queue_depth, set->reserved_tags,
24391c0d
SL
1480 set->numa_node,
1481 BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
24d2f903
CH
1482 if (!tags)
1483 return NULL;
320ae51f 1484
24d2f903
CH
1485 INIT_LIST_HEAD(&tags->page_list);
1486
a5164405
JA
1487 tags->rqs = kzalloc_node(set->queue_depth * sizeof(struct request *),
1488 GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY,
1489 set->numa_node);
24d2f903
CH
1490 if (!tags->rqs) {
1491 blk_mq_free_tags(tags);
1492 return NULL;
1493 }
320ae51f
JA
1494
1495 /*
1496 * rq_size is the size of the request plus driver payload, rounded
1497 * to the cacheline size
1498 */
24d2f903 1499 rq_size = round_up(sizeof(struct request) + set->cmd_size,
320ae51f 1500 cache_line_size());
24d2f903 1501 left = rq_size * set->queue_depth;
320ae51f 1502
24d2f903 1503 for (i = 0; i < set->queue_depth; ) {
320ae51f
JA
1504 int this_order = max_order;
1505 struct page *page;
1506 int to_do;
1507 void *p;
1508
b3a834b1 1509 while (this_order && left < order_to_size(this_order - 1))
320ae51f
JA
1510 this_order--;
1511
1512 do {
a5164405 1513 page = alloc_pages_node(set->numa_node,
ac211175 1514 GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
a5164405 1515 this_order);
320ae51f
JA
1516 if (page)
1517 break;
1518 if (!this_order--)
1519 break;
1520 if (order_to_size(this_order) < rq_size)
1521 break;
1522 } while (1);
1523
1524 if (!page)
24d2f903 1525 goto fail;
320ae51f
JA
1526
1527 page->private = this_order;
24d2f903 1528 list_add_tail(&page->lru, &tags->page_list);
320ae51f
JA
1529
1530 p = page_address(page);
f75782e4
CM
1531 /*
1532 * Allow kmemleak to scan these pages as they contain pointers
1533 * to additional allocations like via ops->init_request().
1534 */
1535 kmemleak_alloc(p, order_to_size(this_order), 1, GFP_KERNEL);
320ae51f 1536 entries_per_page = order_to_size(this_order) / rq_size;
24d2f903 1537 to_do = min(entries_per_page, set->queue_depth - i);
320ae51f
JA
1538 left -= to_do * rq_size;
1539 for (j = 0; j < to_do; j++) {
24d2f903
CH
1540 tags->rqs[i] = p;
1541 if (set->ops->init_request) {
1542 if (set->ops->init_request(set->driver_data,
1543 tags->rqs[i], hctx_idx, i,
a5164405
JA
1544 set->numa_node)) {
1545 tags->rqs[i] = NULL;
24d2f903 1546 goto fail;
a5164405 1547 }
e9b267d9
CH
1548 }
1549
320ae51f
JA
1550 p += rq_size;
1551 i++;
1552 }
1553 }
24d2f903 1554 return tags;
320ae51f 1555
24d2f903 1556fail:
24d2f903
CH
1557 blk_mq_free_rq_map(set, tags, hctx_idx);
1558 return NULL;
320ae51f
JA
1559}
1560
e57690fe
JA
1561/*
1562 * 'cpu' is going away. splice any existing rq_list entries from this
1563 * software queue to the hw queue dispatch list, and ensure that it
1564 * gets run.
1565 */
9467f859 1566static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
484b4061 1567{
9467f859 1568 struct blk_mq_hw_ctx *hctx;
484b4061
JA
1569 struct blk_mq_ctx *ctx;
1570 LIST_HEAD(tmp);
1571
9467f859 1572 hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
e57690fe 1573 ctx = __blk_mq_get_ctx(hctx->queue, cpu);
484b4061
JA
1574
1575 spin_lock(&ctx->lock);
1576 if (!list_empty(&ctx->rq_list)) {
1577 list_splice_init(&ctx->rq_list, &tmp);
1578 blk_mq_hctx_clear_pending(hctx, ctx);
1579 }
1580 spin_unlock(&ctx->lock);
1581
1582 if (list_empty(&tmp))
9467f859 1583 return 0;
484b4061 1584
e57690fe
JA
1585 spin_lock(&hctx->lock);
1586 list_splice_tail_init(&tmp, &hctx->dispatch);
1587 spin_unlock(&hctx->lock);
484b4061
JA
1588
1589 blk_mq_run_hw_queue(hctx, true);
9467f859 1590 return 0;
484b4061
JA
1591}
1592
9467f859 1593static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
484b4061 1594{
9467f859
TG
1595 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
1596 &hctx->cpuhp_dead);
484b4061
JA
1597}
1598
c3b4afca 1599/* hctx->ctxs will be freed in queue's release handler */
08e98fc6
ML
1600static void blk_mq_exit_hctx(struct request_queue *q,
1601 struct blk_mq_tag_set *set,
1602 struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
1603{
f70ced09
ML
1604 unsigned flush_start_tag = set->queue_depth;
1605
08e98fc6
ML
1606 blk_mq_tag_idle(hctx);
1607
f70ced09
ML
1608 if (set->ops->exit_request)
1609 set->ops->exit_request(set->driver_data,
1610 hctx->fq->flush_rq, hctx_idx,
1611 flush_start_tag + hctx_idx);
1612
08e98fc6
ML
1613 if (set->ops->exit_hctx)
1614 set->ops->exit_hctx(hctx, hctx_idx);
1615
9467f859 1616 blk_mq_remove_cpuhp(hctx);
f70ced09 1617 blk_free_flush_queue(hctx->fq);
88459642 1618 sbitmap_free(&hctx->ctx_map);
08e98fc6
ML
1619}
1620
624dbe47
ML
1621static void blk_mq_exit_hw_queues(struct request_queue *q,
1622 struct blk_mq_tag_set *set, int nr_queue)
1623{
1624 struct blk_mq_hw_ctx *hctx;
1625 unsigned int i;
1626
1627 queue_for_each_hw_ctx(q, hctx, i) {
1628 if (i == nr_queue)
1629 break;
08e98fc6 1630 blk_mq_exit_hctx(q, set, hctx, i);
624dbe47 1631 }
624dbe47
ML
1632}
1633
1634static void blk_mq_free_hw_queues(struct request_queue *q,
1635 struct blk_mq_tag_set *set)
1636{
1637 struct blk_mq_hw_ctx *hctx;
1638 unsigned int i;
1639
e09aae7e 1640 queue_for_each_hw_ctx(q, hctx, i)
624dbe47 1641 free_cpumask_var(hctx->cpumask);
624dbe47
ML
1642}
1643
08e98fc6
ML
1644static int blk_mq_init_hctx(struct request_queue *q,
1645 struct blk_mq_tag_set *set,
1646 struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
320ae51f 1647{
08e98fc6 1648 int node;
f70ced09 1649 unsigned flush_start_tag = set->queue_depth;
08e98fc6
ML
1650
1651 node = hctx->numa_node;
1652 if (node == NUMA_NO_NODE)
1653 node = hctx->numa_node = set->numa_node;
1654
27489a3c 1655 INIT_WORK(&hctx->run_work, blk_mq_run_work_fn);
08e98fc6
ML
1656 INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn);
1657 spin_lock_init(&hctx->lock);
1658 INIT_LIST_HEAD(&hctx->dispatch);
1659 hctx->queue = q;
1660 hctx->queue_num = hctx_idx;
2404e607 1661 hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED;
08e98fc6 1662
9467f859 1663 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
08e98fc6
ML
1664
1665 hctx->tags = set->tags[hctx_idx];
320ae51f
JA
1666
1667 /*
08e98fc6
ML
1668 * Allocate space for all possible cpus to avoid allocation at
1669 * runtime
320ae51f 1670 */
08e98fc6
ML
1671 hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *),
1672 GFP_KERNEL, node);
1673 if (!hctx->ctxs)
1674 goto unregister_cpu_notifier;
320ae51f 1675
88459642
OS
1676 if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), GFP_KERNEL,
1677 node))
08e98fc6 1678 goto free_ctxs;
320ae51f 1679
08e98fc6 1680 hctx->nr_ctx = 0;
320ae51f 1681
08e98fc6
ML
1682 if (set->ops->init_hctx &&
1683 set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
1684 goto free_bitmap;
320ae51f 1685
f70ced09
ML
1686 hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size);
1687 if (!hctx->fq)
1688 goto exit_hctx;
320ae51f 1689
f70ced09
ML
1690 if (set->ops->init_request &&
1691 set->ops->init_request(set->driver_data,
1692 hctx->fq->flush_rq, hctx_idx,
1693 flush_start_tag + hctx_idx, node))
1694 goto free_fq;
320ae51f 1695
08e98fc6 1696 return 0;
320ae51f 1697
f70ced09
ML
1698 free_fq:
1699 kfree(hctx->fq);
1700 exit_hctx:
1701 if (set->ops->exit_hctx)
1702 set->ops->exit_hctx(hctx, hctx_idx);
08e98fc6 1703 free_bitmap:
88459642 1704 sbitmap_free(&hctx->ctx_map);
08e98fc6
ML
1705 free_ctxs:
1706 kfree(hctx->ctxs);
1707 unregister_cpu_notifier:
9467f859 1708 blk_mq_remove_cpuhp(hctx);
08e98fc6
ML
1709 return -1;
1710}
320ae51f 1711
320ae51f
JA
1712static void blk_mq_init_cpu_queues(struct request_queue *q,
1713 unsigned int nr_hw_queues)
1714{
1715 unsigned int i;
1716
1717 for_each_possible_cpu(i) {
1718 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
1719 struct blk_mq_hw_ctx *hctx;
1720
1721 memset(__ctx, 0, sizeof(*__ctx));
1722 __ctx->cpu = i;
1723 spin_lock_init(&__ctx->lock);
1724 INIT_LIST_HEAD(&__ctx->rq_list);
1725 __ctx->queue = q;
1726
1727 /* If the cpu isn't online, the cpu is mapped to first hctx */
320ae51f
JA
1728 if (!cpu_online(i))
1729 continue;
1730
7d7e0f90 1731 hctx = blk_mq_map_queue(q, i);
e4043dcf 1732
320ae51f
JA
1733 /*
1734 * Set local node, IFF we have more than one hw queue. If
1735 * not, we remain on the home node of the device
1736 */
1737 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
bffed457 1738 hctx->numa_node = local_memory_node(cpu_to_node(i));
320ae51f
JA
1739 }
1740}
1741
5778322e
AM
1742static void blk_mq_map_swqueue(struct request_queue *q,
1743 const struct cpumask *online_mask)
320ae51f
JA
1744{
1745 unsigned int i;
1746 struct blk_mq_hw_ctx *hctx;
1747 struct blk_mq_ctx *ctx;
2a34c087 1748 struct blk_mq_tag_set *set = q->tag_set;
320ae51f 1749
60de074b
AM
1750 /*
1751 * Avoid others reading imcomplete hctx->cpumask through sysfs
1752 */
1753 mutex_lock(&q->sysfs_lock);
1754
320ae51f 1755 queue_for_each_hw_ctx(q, hctx, i) {
e4043dcf 1756 cpumask_clear(hctx->cpumask);
320ae51f
JA
1757 hctx->nr_ctx = 0;
1758 }
1759
1760 /*
1761 * Map software to hardware queues
1762 */
897bb0c7 1763 for_each_possible_cpu(i) {
320ae51f 1764 /* If the cpu isn't online, the cpu is mapped to first hctx */
5778322e 1765 if (!cpumask_test_cpu(i, online_mask))
e4043dcf
JA
1766 continue;
1767
897bb0c7 1768 ctx = per_cpu_ptr(q->queue_ctx, i);
7d7e0f90 1769 hctx = blk_mq_map_queue(q, i);
868f2f0b 1770
e4043dcf 1771 cpumask_set_cpu(i, hctx->cpumask);
320ae51f
JA
1772 ctx->index_hw = hctx->nr_ctx;
1773 hctx->ctxs[hctx->nr_ctx++] = ctx;
1774 }
506e931f 1775
60de074b
AM
1776 mutex_unlock(&q->sysfs_lock);
1777
506e931f 1778 queue_for_each_hw_ctx(q, hctx, i) {
484b4061 1779 /*
a68aafa5
JA
1780 * If no software queues are mapped to this hardware queue,
1781 * disable it and free the request entries.
484b4061
JA
1782 */
1783 if (!hctx->nr_ctx) {
484b4061
JA
1784 if (set->tags[i]) {
1785 blk_mq_free_rq_map(set, set->tags[i], i);
1786 set->tags[i] = NULL;
484b4061 1787 }
2a34c087 1788 hctx->tags = NULL;
484b4061
JA
1789 continue;
1790 }
1791
2a34c087
ML
1792 /* unmapped hw queue can be remapped after CPU topo changed */
1793 if (!set->tags[i])
1794 set->tags[i] = blk_mq_init_rq_map(set, i);
1795 hctx->tags = set->tags[i];
1796 WARN_ON(!hctx->tags);
1797
889fa31f
CY
1798 /*
1799 * Set the map size to the number of mapped software queues.
1800 * This is more accurate and more efficient than looping
1801 * over all possibly mapped software queues.
1802 */
88459642 1803 sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
889fa31f 1804
484b4061
JA
1805 /*
1806 * Initialize batch roundrobin counts
1807 */
506e931f
JA
1808 hctx->next_cpu = cpumask_first(hctx->cpumask);
1809 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
1810 }
320ae51f
JA
1811}
1812
2404e607 1813static void queue_set_hctx_shared(struct request_queue *q, bool shared)
0d2602ca
JA
1814{
1815 struct blk_mq_hw_ctx *hctx;
0d2602ca
JA
1816 int i;
1817
2404e607
JM
1818 queue_for_each_hw_ctx(q, hctx, i) {
1819 if (shared)
1820 hctx->flags |= BLK_MQ_F_TAG_SHARED;
1821 else
1822 hctx->flags &= ~BLK_MQ_F_TAG_SHARED;
1823 }
1824}
1825
1826static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set, bool shared)
1827{
1828 struct request_queue *q;
0d2602ca
JA
1829
1830 list_for_each_entry(q, &set->tag_list, tag_set_list) {
1831 blk_mq_freeze_queue(q);
2404e607 1832 queue_set_hctx_shared(q, shared);
0d2602ca
JA
1833 blk_mq_unfreeze_queue(q);
1834 }
1835}
1836
1837static void blk_mq_del_queue_tag_set(struct request_queue *q)
1838{
1839 struct blk_mq_tag_set *set = q->tag_set;
1840
0d2602ca
JA
1841 mutex_lock(&set->tag_list_lock);
1842 list_del_init(&q->tag_set_list);
2404e607
JM
1843 if (list_is_singular(&set->tag_list)) {
1844 /* just transitioned to unshared */
1845 set->flags &= ~BLK_MQ_F_TAG_SHARED;
1846 /* update existing queue */
1847 blk_mq_update_tag_set_depth(set, false);
1848 }
0d2602ca 1849 mutex_unlock(&set->tag_list_lock);
0d2602ca
JA
1850}
1851
1852static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
1853 struct request_queue *q)
1854{
1855 q->tag_set = set;
1856
1857 mutex_lock(&set->tag_list_lock);
2404e607
JM
1858
1859 /* Check to see if we're transitioning to shared (from 1 to 2 queues). */
1860 if (!list_empty(&set->tag_list) && !(set->flags & BLK_MQ_F_TAG_SHARED)) {
1861 set->flags |= BLK_MQ_F_TAG_SHARED;
1862 /* update existing queue */
1863 blk_mq_update_tag_set_depth(set, true);
1864 }
1865 if (set->flags & BLK_MQ_F_TAG_SHARED)
1866 queue_set_hctx_shared(q, true);
0d2602ca 1867 list_add_tail(&q->tag_set_list, &set->tag_list);
2404e607 1868
0d2602ca
JA
1869 mutex_unlock(&set->tag_list_lock);
1870}
1871
e09aae7e
ML
1872/*
1873 * It is the actual release handler for mq, but we do it from
1874 * request queue's release handler for avoiding use-after-free
1875 * and headache because q->mq_kobj shouldn't have been introduced,
1876 * but we can't group ctx/kctx kobj without it.
1877 */
1878void blk_mq_release(struct request_queue *q)
1879{
1880 struct blk_mq_hw_ctx *hctx;
1881 unsigned int i;
1882
1883 /* hctx kobj stays in hctx */
c3b4afca
ML
1884 queue_for_each_hw_ctx(q, hctx, i) {
1885 if (!hctx)
1886 continue;
1887 kfree(hctx->ctxs);
e09aae7e 1888 kfree(hctx);
c3b4afca 1889 }
e09aae7e 1890
a723bab3
AM
1891 q->mq_map = NULL;
1892
e09aae7e
ML
1893 kfree(q->queue_hw_ctx);
1894
1895 /* ctx kobj stays in queue_ctx */
1896 free_percpu(q->queue_ctx);
1897}
1898
24d2f903 1899struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
b62c21b7
MS
1900{
1901 struct request_queue *uninit_q, *q;
1902
1903 uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node);
1904 if (!uninit_q)
1905 return ERR_PTR(-ENOMEM);
1906
1907 q = blk_mq_init_allocated_queue(set, uninit_q);
1908 if (IS_ERR(q))
1909 blk_cleanup_queue(uninit_q);
1910
1911 return q;
1912}
1913EXPORT_SYMBOL(blk_mq_init_queue);
1914
868f2f0b
KB
1915static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
1916 struct request_queue *q)
320ae51f 1917{
868f2f0b
KB
1918 int i, j;
1919 struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
f14bbe77 1920
868f2f0b 1921 blk_mq_sysfs_unregister(q);
24d2f903 1922 for (i = 0; i < set->nr_hw_queues; i++) {
868f2f0b 1923 int node;
f14bbe77 1924
868f2f0b
KB
1925 if (hctxs[i])
1926 continue;
1927
1928 node = blk_mq_hw_queue_to_node(q->mq_map, i);
cdef54dd
CH
1929 hctxs[i] = kzalloc_node(sizeof(struct blk_mq_hw_ctx),
1930 GFP_KERNEL, node);
320ae51f 1931 if (!hctxs[i])
868f2f0b 1932 break;
320ae51f 1933
a86073e4 1934 if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL,
868f2f0b
KB
1935 node)) {
1936 kfree(hctxs[i]);
1937 hctxs[i] = NULL;
1938 break;
1939 }
e4043dcf 1940
0d2602ca 1941 atomic_set(&hctxs[i]->nr_active, 0);
f14bbe77 1942 hctxs[i]->numa_node = node;
320ae51f 1943 hctxs[i]->queue_num = i;
868f2f0b
KB
1944
1945 if (blk_mq_init_hctx(q, set, hctxs[i], i)) {
1946 free_cpumask_var(hctxs[i]->cpumask);
1947 kfree(hctxs[i]);
1948 hctxs[i] = NULL;
1949 break;
1950 }
1951 blk_mq_hctx_kobj_init(hctxs[i]);
320ae51f 1952 }
868f2f0b
KB
1953 for (j = i; j < q->nr_hw_queues; j++) {
1954 struct blk_mq_hw_ctx *hctx = hctxs[j];
1955
1956 if (hctx) {
1957 if (hctx->tags) {
1958 blk_mq_free_rq_map(set, hctx->tags, j);
1959 set->tags[j] = NULL;
1960 }
1961 blk_mq_exit_hctx(q, set, hctx, j);
1962 free_cpumask_var(hctx->cpumask);
1963 kobject_put(&hctx->kobj);
1964 kfree(hctx->ctxs);
1965 kfree(hctx);
1966 hctxs[j] = NULL;
1967
1968 }
1969 }
1970 q->nr_hw_queues = i;
1971 blk_mq_sysfs_register(q);
1972}
1973
1974struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
1975 struct request_queue *q)
1976{
66841672
ML
1977 /* mark the queue as mq asap */
1978 q->mq_ops = set->ops;
1979
868f2f0b
KB
1980 q->queue_ctx = alloc_percpu(struct blk_mq_ctx);
1981 if (!q->queue_ctx)
c7de5726 1982 goto err_exit;
868f2f0b
KB
1983
1984 q->queue_hw_ctx = kzalloc_node(nr_cpu_ids * sizeof(*(q->queue_hw_ctx)),
1985 GFP_KERNEL, set->numa_node);
1986 if (!q->queue_hw_ctx)
1987 goto err_percpu;
1988
bdd17e75 1989 q->mq_map = set->mq_map;
868f2f0b
KB
1990
1991 blk_mq_realloc_hw_ctxs(set, q);
1992 if (!q->nr_hw_queues)
1993 goto err_hctxs;
320ae51f 1994
287922eb 1995 INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
e56f698b 1996 blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
320ae51f
JA
1997
1998 q->nr_queues = nr_cpu_ids;
320ae51f 1999
94eddfbe 2000 q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
320ae51f 2001
05f1dd53
JA
2002 if (!(set->flags & BLK_MQ_F_SG_MERGE))
2003 q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE;
2004
1be036e9
CH
2005 q->sg_reserved_size = INT_MAX;
2006
2849450a 2007 INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
6fca6a61
CH
2008 INIT_LIST_HEAD(&q->requeue_list);
2009 spin_lock_init(&q->requeue_lock);
2010
07068d5b
JA
2011 if (q->nr_hw_queues > 1)
2012 blk_queue_make_request(q, blk_mq_make_request);
2013 else
2014 blk_queue_make_request(q, blk_sq_make_request);
2015
eba71768
JA
2016 /*
2017 * Do this after blk_queue_make_request() overrides it...
2018 */
2019 q->nr_requests = set->queue_depth;
2020
24d2f903
CH
2021 if (set->ops->complete)
2022 blk_queue_softirq_done(q, set->ops->complete);
30a91cb4 2023
24d2f903 2024 blk_mq_init_cpu_queues(q, set->nr_hw_queues);
320ae51f 2025
5778322e 2026 get_online_cpus();
320ae51f 2027 mutex_lock(&all_q_mutex);
320ae51f 2028
4593fdbe 2029 list_add_tail(&q->all_q_node, &all_q_list);
0d2602ca 2030 blk_mq_add_queue_tag_set(set, q);
5778322e 2031 blk_mq_map_swqueue(q, cpu_online_mask);
484b4061 2032
4593fdbe 2033 mutex_unlock(&all_q_mutex);
5778322e 2034 put_online_cpus();
4593fdbe 2035
320ae51f 2036 return q;
18741986 2037
320ae51f 2038err_hctxs:
868f2f0b 2039 kfree(q->queue_hw_ctx);
320ae51f 2040err_percpu:
868f2f0b 2041 free_percpu(q->queue_ctx);
c7de5726
ML
2042err_exit:
2043 q->mq_ops = NULL;
320ae51f
JA
2044 return ERR_PTR(-ENOMEM);
2045}
b62c21b7 2046EXPORT_SYMBOL(blk_mq_init_allocated_queue);
320ae51f
JA
2047
2048void blk_mq_free_queue(struct request_queue *q)
2049{
624dbe47 2050 struct blk_mq_tag_set *set = q->tag_set;
320ae51f 2051
0e626368
AM
2052 mutex_lock(&all_q_mutex);
2053 list_del_init(&q->all_q_node);
2054 mutex_unlock(&all_q_mutex);
2055
0d2602ca
JA
2056 blk_mq_del_queue_tag_set(q);
2057
624dbe47
ML
2058 blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
2059 blk_mq_free_hw_queues(q, set);
320ae51f 2060}
320ae51f
JA
2061
2062/* Basically redo blk_mq_init_queue with queue frozen */
5778322e
AM
2063static void blk_mq_queue_reinit(struct request_queue *q,
2064 const struct cpumask *online_mask)
320ae51f 2065{
4ecd4fef 2066 WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth));
320ae51f 2067
67aec14c
JA
2068 blk_mq_sysfs_unregister(q);
2069
320ae51f
JA
2070 /*
2071 * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
2072 * we should change hctx numa_node according to new topology (this
2073 * involves free and re-allocate memory, worthy doing?)
2074 */
2075
5778322e 2076 blk_mq_map_swqueue(q, online_mask);
320ae51f 2077
67aec14c 2078 blk_mq_sysfs_register(q);
320ae51f
JA
2079}
2080
65d5291e
SAS
2081/*
2082 * New online cpumask which is going to be set in this hotplug event.
2083 * Declare this cpumasks as global as cpu-hotplug operation is invoked
2084 * one-by-one and dynamically allocating this could result in a failure.
2085 */
2086static struct cpumask cpuhp_online_new;
2087
2088static void blk_mq_queue_reinit_work(void)
320ae51f
JA
2089{
2090 struct request_queue *q;
320ae51f
JA
2091
2092 mutex_lock(&all_q_mutex);
f3af020b
TH
2093 /*
2094 * We need to freeze and reinit all existing queues. Freezing
2095 * involves synchronous wait for an RCU grace period and doing it
2096 * one by one may take a long time. Start freezing all queues in
2097 * one swoop and then wait for the completions so that freezing can
2098 * take place in parallel.
2099 */
2100 list_for_each_entry(q, &all_q_list, all_q_node)
2101 blk_mq_freeze_queue_start(q);
f054b56c 2102 list_for_each_entry(q, &all_q_list, all_q_node) {
f3af020b
TH
2103 blk_mq_freeze_queue_wait(q);
2104
f054b56c
ML
2105 /*
2106 * timeout handler can't touch hw queue during the
2107 * reinitialization
2108 */
2109 del_timer_sync(&q->timeout);
2110 }
2111
320ae51f 2112 list_for_each_entry(q, &all_q_list, all_q_node)
65d5291e 2113 blk_mq_queue_reinit(q, &cpuhp_online_new);
f3af020b
TH
2114
2115 list_for_each_entry(q, &all_q_list, all_q_node)
2116 blk_mq_unfreeze_queue(q);
2117
320ae51f 2118 mutex_unlock(&all_q_mutex);
65d5291e
SAS
2119}
2120
2121static int blk_mq_queue_reinit_dead(unsigned int cpu)
2122{
97a32864 2123 cpumask_copy(&cpuhp_online_new, cpu_online_mask);
65d5291e
SAS
2124 blk_mq_queue_reinit_work();
2125 return 0;
2126}
2127
2128/*
2129 * Before hotadded cpu starts handling requests, new mappings must be
2130 * established. Otherwise, these requests in hw queue might never be
2131 * dispatched.
2132 *
2133 * For example, there is a single hw queue (hctx) and two CPU queues (ctx0
2134 * for CPU0, and ctx1 for CPU1).
2135 *
2136 * Now CPU1 is just onlined and a request is inserted into ctx1->rq_list
2137 * and set bit0 in pending bitmap as ctx1->index_hw is still zero.
2138 *
2139 * And then while running hw queue, flush_busy_ctxs() finds bit0 is set in
2140 * pending bitmap and tries to retrieve requests in hctx->ctxs[0]->rq_list.
2141 * But htx->ctxs[0] is a pointer to ctx0, so the request in ctx1->rq_list
2142 * is ignored.
2143 */
2144static int blk_mq_queue_reinit_prepare(unsigned int cpu)
2145{
2146 cpumask_copy(&cpuhp_online_new, cpu_online_mask);
2147 cpumask_set_cpu(cpu, &cpuhp_online_new);
2148 blk_mq_queue_reinit_work();
2149 return 0;
320ae51f
JA
2150}
2151
a5164405
JA
2152static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
2153{
2154 int i;
2155
2156 for (i = 0; i < set->nr_hw_queues; i++) {
2157 set->tags[i] = blk_mq_init_rq_map(set, i);
2158 if (!set->tags[i])
2159 goto out_unwind;
2160 }
2161
2162 return 0;
2163
2164out_unwind:
2165 while (--i >= 0)
2166 blk_mq_free_rq_map(set, set->tags[i], i);
2167
a5164405
JA
2168 return -ENOMEM;
2169}
2170
2171/*
2172 * Allocate the request maps associated with this tag_set. Note that this
2173 * may reduce the depth asked for, if memory is tight. set->queue_depth
2174 * will be updated to reflect the allocated depth.
2175 */
2176static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
2177{
2178 unsigned int depth;
2179 int err;
2180
2181 depth = set->queue_depth;
2182 do {
2183 err = __blk_mq_alloc_rq_maps(set);
2184 if (!err)
2185 break;
2186
2187 set->queue_depth >>= 1;
2188 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
2189 err = -ENOMEM;
2190 break;
2191 }
2192 } while (set->queue_depth);
2193
2194 if (!set->queue_depth || err) {
2195 pr_err("blk-mq: failed to allocate request map\n");
2196 return -ENOMEM;
2197 }
2198
2199 if (depth != set->queue_depth)
2200 pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
2201 depth, set->queue_depth);
2202
2203 return 0;
2204}
2205
a4391c64
JA
2206/*
2207 * Alloc a tag set to be associated with one or more request queues.
2208 * May fail with EINVAL for various error conditions. May adjust the
2209 * requested depth down, if if it too large. In that case, the set
2210 * value will be stored in set->queue_depth.
2211 */
24d2f903
CH
2212int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
2213{
da695ba2
CH
2214 int ret;
2215
205fb5f5
BVA
2216 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
2217
24d2f903
CH
2218 if (!set->nr_hw_queues)
2219 return -EINVAL;
a4391c64 2220 if (!set->queue_depth)
24d2f903
CH
2221 return -EINVAL;
2222 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
2223 return -EINVAL;
2224
7d7e0f90 2225 if (!set->ops->queue_rq)
24d2f903
CH
2226 return -EINVAL;
2227
a4391c64
JA
2228 if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
2229 pr_info("blk-mq: reduced tag depth to %u\n",
2230 BLK_MQ_MAX_DEPTH);
2231 set->queue_depth = BLK_MQ_MAX_DEPTH;
2232 }
24d2f903 2233
6637fadf
SL
2234 /*
2235 * If a crashdump is active, then we are potentially in a very
2236 * memory constrained environment. Limit us to 1 queue and
2237 * 64 tags to prevent using too much memory.
2238 */
2239 if (is_kdump_kernel()) {
2240 set->nr_hw_queues = 1;
2241 set->queue_depth = min(64U, set->queue_depth);
2242 }
868f2f0b
KB
2243 /*
2244 * There is no use for more h/w queues than cpus.
2245 */
2246 if (set->nr_hw_queues > nr_cpu_ids)
2247 set->nr_hw_queues = nr_cpu_ids;
6637fadf 2248
868f2f0b 2249 set->tags = kzalloc_node(nr_cpu_ids * sizeof(struct blk_mq_tags *),
24d2f903
CH
2250 GFP_KERNEL, set->numa_node);
2251 if (!set->tags)
a5164405 2252 return -ENOMEM;
24d2f903 2253
da695ba2
CH
2254 ret = -ENOMEM;
2255 set->mq_map = kzalloc_node(sizeof(*set->mq_map) * nr_cpu_ids,
2256 GFP_KERNEL, set->numa_node);
bdd17e75
CH
2257 if (!set->mq_map)
2258 goto out_free_tags;
2259
da695ba2
CH
2260 if (set->ops->map_queues)
2261 ret = set->ops->map_queues(set);
2262 else
2263 ret = blk_mq_map_queues(set);
2264 if (ret)
2265 goto out_free_mq_map;
2266
2267 ret = blk_mq_alloc_rq_maps(set);
2268 if (ret)
bdd17e75 2269 goto out_free_mq_map;
24d2f903 2270
0d2602ca
JA
2271 mutex_init(&set->tag_list_lock);
2272 INIT_LIST_HEAD(&set->tag_list);
2273
24d2f903 2274 return 0;
bdd17e75
CH
2275
2276out_free_mq_map:
2277 kfree(set->mq_map);
2278 set->mq_map = NULL;
2279out_free_tags:
5676e7b6
RE
2280 kfree(set->tags);
2281 set->tags = NULL;
da695ba2 2282 return ret;
24d2f903
CH
2283}
2284EXPORT_SYMBOL(blk_mq_alloc_tag_set);
2285
2286void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
2287{
2288 int i;
2289
868f2f0b 2290 for (i = 0; i < nr_cpu_ids; i++) {
f42d79ab 2291 if (set->tags[i])
484b4061
JA
2292 blk_mq_free_rq_map(set, set->tags[i], i);
2293 }
2294
bdd17e75
CH
2295 kfree(set->mq_map);
2296 set->mq_map = NULL;
2297
981bd189 2298 kfree(set->tags);
5676e7b6 2299 set->tags = NULL;
24d2f903
CH
2300}
2301EXPORT_SYMBOL(blk_mq_free_tag_set);
2302
e3a2b3f9
JA
2303int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
2304{
2305 struct blk_mq_tag_set *set = q->tag_set;
2306 struct blk_mq_hw_ctx *hctx;
2307 int i, ret;
2308
2309 if (!set || nr > set->queue_depth)
2310 return -EINVAL;
2311
2312 ret = 0;
2313 queue_for_each_hw_ctx(q, hctx, i) {
e9137d4b
KB
2314 if (!hctx->tags)
2315 continue;
e3a2b3f9
JA
2316 ret = blk_mq_tag_update_depth(hctx->tags, nr);
2317 if (ret)
2318 break;
2319 }
2320
2321 if (!ret)
2322 q->nr_requests = nr;
2323
2324 return ret;
2325}
2326
868f2f0b
KB
2327void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
2328{
2329 struct request_queue *q;
2330
2331 if (nr_hw_queues > nr_cpu_ids)
2332 nr_hw_queues = nr_cpu_ids;
2333 if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues)
2334 return;
2335
2336 list_for_each_entry(q, &set->tag_list, tag_set_list)
2337 blk_mq_freeze_queue(q);
2338
2339 set->nr_hw_queues = nr_hw_queues;
2340 list_for_each_entry(q, &set->tag_list, tag_set_list) {
2341 blk_mq_realloc_hw_ctxs(set, q);
2342
2343 if (q->nr_hw_queues > 1)
2344 blk_queue_make_request(q, blk_mq_make_request);
2345 else
2346 blk_queue_make_request(q, blk_sq_make_request);
2347
2348 blk_mq_queue_reinit(q, cpu_online_mask);
2349 }
2350
2351 list_for_each_entry(q, &set->tag_list, tag_set_list)
2352 blk_mq_unfreeze_queue(q);
2353}
2354EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
2355
676141e4
JA
2356void blk_mq_disable_hotplug(void)
2357{
2358 mutex_lock(&all_q_mutex);
2359}
2360
2361void blk_mq_enable_hotplug(void)
2362{
2363 mutex_unlock(&all_q_mutex);
2364}
2365
320ae51f
JA
2366static int __init blk_mq_init(void)
2367{
9467f859
TG
2368 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
2369 blk_mq_hctx_notify_dead);
320ae51f 2370
65d5291e
SAS
2371 cpuhp_setup_state_nocalls(CPUHP_BLK_MQ_PREPARE, "block/mq:prepare",
2372 blk_mq_queue_reinit_prepare,
2373 blk_mq_queue_reinit_dead);
320ae51f
JA
2374 return 0;
2375}
2376subsys_initcall(blk_mq_init);