Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Block multiqueue core code
4 : *
5 : * Copyright (C) 2013-2014 Jens Axboe
6 : * Copyright (C) 2013-2014 Christoph Hellwig
7 : */
8 : #include <linux/kernel.h>
9 : #include <linux/module.h>
10 : #include <linux/backing-dev.h>
11 : #include <linux/bio.h>
12 : #include <linux/blkdev.h>
13 : #include <linux/blk-integrity.h>
14 : #include <linux/kmemleak.h>
15 : #include <linux/mm.h>
16 : #include <linux/init.h>
17 : #include <linux/slab.h>
18 : #include <linux/workqueue.h>
19 : #include <linux/smp.h>
20 : #include <linux/interrupt.h>
21 : #include <linux/llist.h>
22 : #include <linux/cpu.h>
23 : #include <linux/cache.h>
24 : #include <linux/sched/sysctl.h>
25 : #include <linux/sched/topology.h>
26 : #include <linux/sched/signal.h>
27 : #include <linux/delay.h>
28 : #include <linux/crash_dump.h>
29 : #include <linux/prefetch.h>
30 : #include <linux/blk-crypto.h>
31 : #include <linux/part_stat.h>
32 :
33 : #include <trace/events/block.h>
34 :
35 : #include <linux/t10-pi.h>
36 : #include "blk.h"
37 : #include "blk-mq.h"
38 : #include "blk-mq-debugfs.h"
39 : #include "blk-pm.h"
40 : #include "blk-stat.h"
41 : #include "blk-mq-sched.h"
42 : #include "blk-rq-qos.h"
43 : #include "blk-ioprio.h"
44 :
45 : static DEFINE_PER_CPU(struct llist_head, blk_cpu_done);
46 :
47 : static void blk_mq_insert_request(struct request *rq, blk_insert_t flags);
48 : static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
49 : struct list_head *list);
50 :
51 : static inline struct blk_mq_hw_ctx *blk_qc_to_hctx(struct request_queue *q,
52 : blk_qc_t qc)
53 : {
54 0 : return xa_load(&q->hctx_table, qc);
55 : }
56 :
57 : static inline blk_qc_t blk_rq_to_qc(struct request *rq)
58 : {
59 0 : return rq->mq_hctx->queue_num;
60 : }
61 :
62 : /*
63 : * Check if any of the ctx, dispatch list or elevator
64 : * have pending work in this hardware queue.
65 : */
66 0 : static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
67 : {
68 0 : return !list_empty_careful(&hctx->dispatch) ||
69 0 : sbitmap_any_bit_set(&hctx->ctx_map) ||
70 0 : blk_mq_sched_has_work(hctx);
71 : }
72 :
73 : /*
74 : * Mark this ctx as having pending work in this hardware queue
75 : */
76 0 : static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx,
77 : struct blk_mq_ctx *ctx)
78 : {
79 0 : const int bit = ctx->index_hw[hctx->type];
80 :
81 0 : if (!sbitmap_test_bit(&hctx->ctx_map, bit))
82 0 : sbitmap_set_bit(&hctx->ctx_map, bit);
83 0 : }
84 :
85 : static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx,
86 : struct blk_mq_ctx *ctx)
87 : {
88 0 : const int bit = ctx->index_hw[hctx->type];
89 :
90 0 : sbitmap_clear_bit(&hctx->ctx_map, bit);
91 : }
92 :
93 : struct mq_inflight {
94 : struct block_device *part;
95 : unsigned int inflight[2];
96 : };
97 :
98 0 : static bool blk_mq_check_inflight(struct request *rq, void *priv)
99 : {
100 0 : struct mq_inflight *mi = priv;
101 :
102 0 : if (rq->part && blk_do_io_stat(rq) &&
103 0 : (!mi->part->bd_partno || rq->part == mi->part) &&
104 0 : blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
105 0 : mi->inflight[rq_data_dir(rq)]++;
106 :
107 0 : return true;
108 : }
109 :
110 0 : unsigned int blk_mq_in_flight(struct request_queue *q,
111 : struct block_device *part)
112 : {
113 0 : struct mq_inflight mi = { .part = part };
114 :
115 0 : blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
116 :
117 0 : return mi.inflight[0] + mi.inflight[1];
118 : }
119 :
120 0 : void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
121 : unsigned int inflight[2])
122 : {
123 0 : struct mq_inflight mi = { .part = part };
124 :
125 0 : blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
126 0 : inflight[0] = mi.inflight[0];
127 0 : inflight[1] = mi.inflight[1];
128 0 : }
129 :
130 0 : void blk_freeze_queue_start(struct request_queue *q)
131 : {
132 0 : mutex_lock(&q->mq_freeze_lock);
133 0 : if (++q->mq_freeze_depth == 1) {
134 0 : percpu_ref_kill(&q->q_usage_counter);
135 0 : mutex_unlock(&q->mq_freeze_lock);
136 0 : if (queue_is_mq(q))
137 0 : blk_mq_run_hw_queues(q, false);
138 : } else {
139 0 : mutex_unlock(&q->mq_freeze_lock);
140 : }
141 0 : }
142 : EXPORT_SYMBOL_GPL(blk_freeze_queue_start);
143 :
144 0 : void blk_mq_freeze_queue_wait(struct request_queue *q)
145 : {
146 0 : wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter));
147 0 : }
148 : EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait);
149 :
150 0 : int blk_mq_freeze_queue_wait_timeout(struct request_queue *q,
151 : unsigned long timeout)
152 : {
153 0 : return wait_event_timeout(q->mq_freeze_wq,
154 : percpu_ref_is_zero(&q->q_usage_counter),
155 : timeout);
156 : }
157 : EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout);
158 :
159 : /*
160 : * Guarantee no request is in use, so we can change any data structure of
161 : * the queue afterward.
162 : */
163 0 : void blk_freeze_queue(struct request_queue *q)
164 : {
165 : /*
166 : * In the !blk_mq case we are only calling this to kill the
167 : * q_usage_counter, otherwise this increases the freeze depth
168 : * and waits for it to return to zero. For this reason there is
169 : * no blk_unfreeze_queue(), and blk_freeze_queue() is not
170 : * exported to drivers as the only user for unfreeze is blk_mq.
171 : */
172 0 : blk_freeze_queue_start(q);
173 0 : blk_mq_freeze_queue_wait(q);
174 0 : }
175 :
176 0 : void blk_mq_freeze_queue(struct request_queue *q)
177 : {
178 : /*
179 : * ...just an alias to keep freeze and unfreeze actions balanced
180 : * in the blk_mq_* namespace
181 : */
182 0 : blk_freeze_queue(q);
183 0 : }
184 : EXPORT_SYMBOL_GPL(blk_mq_freeze_queue);
185 :
186 0 : void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic)
187 : {
188 0 : mutex_lock(&q->mq_freeze_lock);
189 0 : if (force_atomic)
190 0 : q->q_usage_counter.data->force_atomic = true;
191 0 : q->mq_freeze_depth--;
192 0 : WARN_ON_ONCE(q->mq_freeze_depth < 0);
193 0 : if (!q->mq_freeze_depth) {
194 0 : percpu_ref_resurrect(&q->q_usage_counter);
195 0 : wake_up_all(&q->mq_freeze_wq);
196 : }
197 0 : mutex_unlock(&q->mq_freeze_lock);
198 0 : }
199 :
200 0 : void blk_mq_unfreeze_queue(struct request_queue *q)
201 : {
202 0 : __blk_mq_unfreeze_queue(q, false);
203 0 : }
204 : EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
205 :
206 : /*
207 : * FIXME: replace the scsi_internal_device_*block_nowait() calls in the
208 : * mpt3sas driver such that this function can be removed.
209 : */
210 0 : void blk_mq_quiesce_queue_nowait(struct request_queue *q)
211 : {
212 : unsigned long flags;
213 :
214 0 : spin_lock_irqsave(&q->queue_lock, flags);
215 0 : if (!q->quiesce_depth++)
216 0 : blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q);
217 0 : spin_unlock_irqrestore(&q->queue_lock, flags);
218 0 : }
219 : EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait);
220 :
221 : /**
222 : * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done
223 : * @set: tag_set to wait on
224 : *
225 : * Note: it is driver's responsibility for making sure that quiesce has
226 : * been started on or more of the request_queues of the tag_set. This
227 : * function only waits for the quiesce on those request_queues that had
228 : * the quiesce flag set using blk_mq_quiesce_queue_nowait.
229 : */
230 0 : void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set)
231 : {
232 0 : if (set->flags & BLK_MQ_F_BLOCKING)
233 0 : synchronize_srcu(set->srcu);
234 : else
235 0 : synchronize_rcu();
236 0 : }
237 : EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done);
238 :
239 : /**
240 : * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished
241 : * @q: request queue.
242 : *
243 : * Note: this function does not prevent that the struct request end_io()
244 : * callback function is invoked. Once this function is returned, we make
245 : * sure no dispatch can happen until the queue is unquiesced via
246 : * blk_mq_unquiesce_queue().
247 : */
248 0 : void blk_mq_quiesce_queue(struct request_queue *q)
249 : {
250 0 : blk_mq_quiesce_queue_nowait(q);
251 : /* nothing to wait for non-mq queues */
252 0 : if (queue_is_mq(q))
253 0 : blk_mq_wait_quiesce_done(q->tag_set);
254 0 : }
255 : EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue);
256 :
257 : /*
258 : * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue()
259 : * @q: request queue.
260 : *
261 : * This function recovers queue into the state before quiescing
262 : * which is done by blk_mq_quiesce_queue.
263 : */
264 0 : void blk_mq_unquiesce_queue(struct request_queue *q)
265 : {
266 : unsigned long flags;
267 0 : bool run_queue = false;
268 :
269 0 : spin_lock_irqsave(&q->queue_lock, flags);
270 0 : if (WARN_ON_ONCE(q->quiesce_depth <= 0)) {
271 : ;
272 0 : } else if (!--q->quiesce_depth) {
273 0 : blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q);
274 0 : run_queue = true;
275 : }
276 0 : spin_unlock_irqrestore(&q->queue_lock, flags);
277 :
278 : /* dispatch requests which are inserted during quiescing */
279 0 : if (run_queue)
280 0 : blk_mq_run_hw_queues(q, true);
281 0 : }
282 : EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue);
283 :
284 0 : void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set)
285 : {
286 : struct request_queue *q;
287 :
288 0 : mutex_lock(&set->tag_list_lock);
289 0 : list_for_each_entry(q, &set->tag_list, tag_set_list) {
290 0 : if (!blk_queue_skip_tagset_quiesce(q))
291 0 : blk_mq_quiesce_queue_nowait(q);
292 : }
293 0 : blk_mq_wait_quiesce_done(set);
294 0 : mutex_unlock(&set->tag_list_lock);
295 0 : }
296 : EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset);
297 :
298 0 : void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set)
299 : {
300 : struct request_queue *q;
301 :
302 0 : mutex_lock(&set->tag_list_lock);
303 0 : list_for_each_entry(q, &set->tag_list, tag_set_list) {
304 0 : if (!blk_queue_skip_tagset_quiesce(q))
305 0 : blk_mq_unquiesce_queue(q);
306 : }
307 0 : mutex_unlock(&set->tag_list_lock);
308 0 : }
309 : EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset);
310 :
311 0 : void blk_mq_wake_waiters(struct request_queue *q)
312 : {
313 : struct blk_mq_hw_ctx *hctx;
314 : unsigned long i;
315 :
316 0 : queue_for_each_hw_ctx(q, hctx, i)
317 0 : if (blk_mq_hw_queue_mapped(hctx))
318 0 : blk_mq_tag_wakeup_all(hctx->tags, true);
319 0 : }
320 :
321 0 : void blk_rq_init(struct request_queue *q, struct request *rq)
322 : {
323 0 : memset(rq, 0, sizeof(*rq));
324 :
325 0 : INIT_LIST_HEAD(&rq->queuelist);
326 0 : rq->q = q;
327 0 : rq->__sector = (sector_t) -1;
328 0 : INIT_HLIST_NODE(&rq->hash);
329 0 : RB_CLEAR_NODE(&rq->rb_node);
330 0 : rq->tag = BLK_MQ_NO_TAG;
331 0 : rq->internal_tag = BLK_MQ_NO_TAG;
332 0 : rq->start_time_ns = ktime_get_ns();
333 0 : rq->part = NULL;
334 0 : blk_crypto_rq_set_defaults(rq);
335 0 : }
336 : EXPORT_SYMBOL(blk_rq_init);
337 :
338 0 : static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
339 : struct blk_mq_tags *tags, unsigned int tag, u64 alloc_time_ns)
340 : {
341 0 : struct blk_mq_ctx *ctx = data->ctx;
342 0 : struct blk_mq_hw_ctx *hctx = data->hctx;
343 0 : struct request_queue *q = data->q;
344 0 : struct request *rq = tags->static_rqs[tag];
345 :
346 0 : rq->q = q;
347 0 : rq->mq_ctx = ctx;
348 0 : rq->mq_hctx = hctx;
349 0 : rq->cmd_flags = data->cmd_flags;
350 :
351 0 : if (data->flags & BLK_MQ_REQ_PM)
352 0 : data->rq_flags |= RQF_PM;
353 0 : if (blk_queue_io_stat(q))
354 0 : data->rq_flags |= RQF_IO_STAT;
355 0 : rq->rq_flags = data->rq_flags;
356 :
357 0 : if (!(data->rq_flags & RQF_ELV)) {
358 0 : rq->tag = tag;
359 0 : rq->internal_tag = BLK_MQ_NO_TAG;
360 : } else {
361 0 : rq->tag = BLK_MQ_NO_TAG;
362 0 : rq->internal_tag = tag;
363 : }
364 0 : rq->timeout = 0;
365 :
366 0 : if (blk_mq_need_time_stamp(rq))
367 0 : rq->start_time_ns = ktime_get_ns();
368 : else
369 0 : rq->start_time_ns = 0;
370 0 : rq->part = NULL;
371 : #ifdef CONFIG_BLK_RQ_ALLOC_TIME
372 : rq->alloc_time_ns = alloc_time_ns;
373 : #endif
374 0 : rq->io_start_time_ns = 0;
375 0 : rq->stats_sectors = 0;
376 0 : rq->nr_phys_segments = 0;
377 : #if defined(CONFIG_BLK_DEV_INTEGRITY)
378 : rq->nr_integrity_segments = 0;
379 : #endif
380 0 : rq->end_io = NULL;
381 0 : rq->end_io_data = NULL;
382 :
383 0 : blk_crypto_rq_set_defaults(rq);
384 0 : INIT_LIST_HEAD(&rq->queuelist);
385 : /* tag was already set */
386 0 : WRITE_ONCE(rq->deadline, 0);
387 0 : req_ref_set(rq, 1);
388 :
389 0 : if (rq->rq_flags & RQF_ELV) {
390 0 : struct elevator_queue *e = data->q->elevator;
391 :
392 0 : INIT_HLIST_NODE(&rq->hash);
393 0 : RB_CLEAR_NODE(&rq->rb_node);
394 :
395 0 : if (!op_is_flush(data->cmd_flags) &&
396 0 : e->type->ops.prepare_request) {
397 0 : e->type->ops.prepare_request(rq);
398 0 : rq->rq_flags |= RQF_ELVPRIV;
399 : }
400 : }
401 :
402 0 : return rq;
403 : }
404 :
405 : static inline struct request *
406 0 : __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data,
407 : u64 alloc_time_ns)
408 : {
409 : unsigned int tag, tag_offset;
410 : struct blk_mq_tags *tags;
411 : struct request *rq;
412 : unsigned long tag_mask;
413 0 : int i, nr = 0;
414 :
415 0 : tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset);
416 0 : if (unlikely(!tag_mask))
417 : return NULL;
418 :
419 0 : tags = blk_mq_tags_from_data(data);
420 0 : for (i = 0; tag_mask; i++) {
421 0 : if (!(tag_mask & (1UL << i)))
422 0 : continue;
423 0 : tag = tag_offset + i;
424 0 : prefetch(tags->static_rqs[tag]);
425 0 : tag_mask &= ~(1UL << i);
426 0 : rq = blk_mq_rq_ctx_init(data, tags, tag, alloc_time_ns);
427 0 : rq_list_add(data->cached_rq, rq);
428 0 : nr++;
429 : }
430 : /* caller already holds a reference, add for remainder */
431 0 : percpu_ref_get_many(&data->q->q_usage_counter, nr - 1);
432 0 : data->nr_tags -= nr;
433 :
434 0 : return rq_list_pop(data->cached_rq);
435 : }
436 :
437 0 : static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data)
438 : {
439 0 : struct request_queue *q = data->q;
440 0 : u64 alloc_time_ns = 0;
441 : struct request *rq;
442 : unsigned int tag;
443 :
444 : /* alloc_time includes depth and tag waits */
445 : if (blk_queue_rq_alloc_time(q))
446 : alloc_time_ns = ktime_get_ns();
447 :
448 0 : if (data->cmd_flags & REQ_NOWAIT)
449 0 : data->flags |= BLK_MQ_REQ_NOWAIT;
450 :
451 0 : if (q->elevator) {
452 0 : struct elevator_queue *e = q->elevator;
453 :
454 0 : data->rq_flags |= RQF_ELV;
455 :
456 : /*
457 : * Flush/passthrough requests are special and go directly to the
458 : * dispatch list. Don't include reserved tags in the
459 : * limiting, as it isn't useful.
460 : */
461 0 : if (!op_is_flush(data->cmd_flags) &&
462 0 : !blk_op_is_passthrough(data->cmd_flags) &&
463 0 : e->type->ops.limit_depth &&
464 0 : !(data->flags & BLK_MQ_REQ_RESERVED))
465 0 : e->type->ops.limit_depth(data->cmd_flags, data);
466 : }
467 :
468 : retry:
469 0 : data->ctx = blk_mq_get_ctx(q);
470 0 : data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx);
471 0 : if (!(data->rq_flags & RQF_ELV))
472 0 : blk_mq_tag_busy(data->hctx);
473 :
474 0 : if (data->flags & BLK_MQ_REQ_RESERVED)
475 0 : data->rq_flags |= RQF_RESV;
476 :
477 : /*
478 : * Try batched alloc if we want more than 1 tag.
479 : */
480 0 : if (data->nr_tags > 1) {
481 0 : rq = __blk_mq_alloc_requests_batch(data, alloc_time_ns);
482 0 : if (rq)
483 : return rq;
484 0 : data->nr_tags = 1;
485 : }
486 :
487 : /*
488 : * Waiting allocations only fail because of an inactive hctx. In that
489 : * case just retry the hctx assignment and tag allocation as CPU hotplug
490 : * should have migrated us to an online CPU by now.
491 : */
492 0 : tag = blk_mq_get_tag(data);
493 0 : if (tag == BLK_MQ_NO_TAG) {
494 0 : if (data->flags & BLK_MQ_REQ_NOWAIT)
495 : return NULL;
496 : /*
497 : * Give up the CPU and sleep for a random short time to
498 : * ensure that thread using a realtime scheduling class
499 : * are migrated off the CPU, and thus off the hctx that
500 : * is going away.
501 : */
502 0 : msleep(3);
503 0 : goto retry;
504 : }
505 :
506 0 : return blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag,
507 : alloc_time_ns);
508 : }
509 :
510 0 : static struct request *blk_mq_rq_cache_fill(struct request_queue *q,
511 : struct blk_plug *plug,
512 : blk_opf_t opf,
513 : blk_mq_req_flags_t flags)
514 : {
515 0 : struct blk_mq_alloc_data data = {
516 : .q = q,
517 : .flags = flags,
518 : .cmd_flags = opf,
519 0 : .nr_tags = plug->nr_ios,
520 0 : .cached_rq = &plug->cached_rq,
521 : };
522 : struct request *rq;
523 :
524 0 : if (blk_queue_enter(q, flags))
525 : return NULL;
526 :
527 0 : plug->nr_ios = 1;
528 :
529 0 : rq = __blk_mq_alloc_requests(&data);
530 0 : if (unlikely(!rq))
531 0 : blk_queue_exit(q);
532 : return rq;
533 : }
534 :
535 0 : static struct request *blk_mq_alloc_cached_request(struct request_queue *q,
536 : blk_opf_t opf,
537 : blk_mq_req_flags_t flags)
538 : {
539 0 : struct blk_plug *plug = current->plug;
540 : struct request *rq;
541 :
542 0 : if (!plug)
543 : return NULL;
544 :
545 0 : if (rq_list_empty(plug->cached_rq)) {
546 0 : if (plug->nr_ios == 1)
547 : return NULL;
548 0 : rq = blk_mq_rq_cache_fill(q, plug, opf, flags);
549 0 : if (!rq)
550 : return NULL;
551 : } else {
552 0 : rq = rq_list_peek(&plug->cached_rq);
553 0 : if (!rq || rq->q != q)
554 : return NULL;
555 :
556 0 : if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type)
557 : return NULL;
558 0 : if (op_is_flush(rq->cmd_flags) != op_is_flush(opf))
559 : return NULL;
560 :
561 0 : plug->cached_rq = rq_list_next(rq);
562 : }
563 :
564 0 : rq->cmd_flags = opf;
565 0 : INIT_LIST_HEAD(&rq->queuelist);
566 0 : return rq;
567 : }
568 :
569 0 : struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf,
570 : blk_mq_req_flags_t flags)
571 : {
572 : struct request *rq;
573 :
574 0 : rq = blk_mq_alloc_cached_request(q, opf, flags);
575 0 : if (!rq) {
576 0 : struct blk_mq_alloc_data data = {
577 : .q = q,
578 : .flags = flags,
579 : .cmd_flags = opf,
580 : .nr_tags = 1,
581 : };
582 : int ret;
583 :
584 0 : ret = blk_queue_enter(q, flags);
585 0 : if (ret)
586 0 : return ERR_PTR(ret);
587 :
588 0 : rq = __blk_mq_alloc_requests(&data);
589 0 : if (!rq)
590 : goto out_queue_exit;
591 : }
592 0 : rq->__data_len = 0;
593 0 : rq->__sector = (sector_t) -1;
594 0 : rq->bio = rq->biotail = NULL;
595 0 : return rq;
596 : out_queue_exit:
597 0 : blk_queue_exit(q);
598 0 : return ERR_PTR(-EWOULDBLOCK);
599 : }
600 : EXPORT_SYMBOL(blk_mq_alloc_request);
601 :
602 0 : struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
603 : blk_opf_t opf, blk_mq_req_flags_t flags, unsigned int hctx_idx)
604 : {
605 0 : struct blk_mq_alloc_data data = {
606 : .q = q,
607 : .flags = flags,
608 : .cmd_flags = opf,
609 : .nr_tags = 1,
610 : };
611 0 : u64 alloc_time_ns = 0;
612 : struct request *rq;
613 : unsigned int cpu;
614 : unsigned int tag;
615 : int ret;
616 :
617 : /* alloc_time includes depth and tag waits */
618 : if (blk_queue_rq_alloc_time(q))
619 : alloc_time_ns = ktime_get_ns();
620 :
621 : /*
622 : * If the tag allocator sleeps we could get an allocation for a
623 : * different hardware context. No need to complicate the low level
624 : * allocator for this for the rare use case of a command tied to
625 : * a specific queue.
626 : */
627 0 : if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)) ||
628 0 : WARN_ON_ONCE(!(flags & BLK_MQ_REQ_RESERVED)))
629 : return ERR_PTR(-EINVAL);
630 :
631 0 : if (hctx_idx >= q->nr_hw_queues)
632 : return ERR_PTR(-EIO);
633 :
634 0 : ret = blk_queue_enter(q, flags);
635 0 : if (ret)
636 0 : return ERR_PTR(ret);
637 :
638 : /*
639 : * Check if the hardware context is actually mapped to anything.
640 : * If not tell the caller that it should skip this queue.
641 : */
642 0 : ret = -EXDEV;
643 0 : data.hctx = xa_load(&q->hctx_table, hctx_idx);
644 0 : if (!blk_mq_hw_queue_mapped(data.hctx))
645 : goto out_queue_exit;
646 0 : cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask);
647 0 : if (cpu >= nr_cpu_ids)
648 : goto out_queue_exit;
649 0 : data.ctx = __blk_mq_get_ctx(q, cpu);
650 :
651 0 : if (!q->elevator)
652 0 : blk_mq_tag_busy(data.hctx);
653 : else
654 0 : data.rq_flags |= RQF_ELV;
655 :
656 0 : if (flags & BLK_MQ_REQ_RESERVED)
657 0 : data.rq_flags |= RQF_RESV;
658 :
659 0 : ret = -EWOULDBLOCK;
660 0 : tag = blk_mq_get_tag(&data);
661 0 : if (tag == BLK_MQ_NO_TAG)
662 : goto out_queue_exit;
663 0 : rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag,
664 : alloc_time_ns);
665 0 : rq->__data_len = 0;
666 0 : rq->__sector = (sector_t) -1;
667 0 : rq->bio = rq->biotail = NULL;
668 0 : return rq;
669 :
670 : out_queue_exit:
671 0 : blk_queue_exit(q);
672 0 : return ERR_PTR(ret);
673 : }
674 : EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
675 :
676 0 : static void __blk_mq_free_request(struct request *rq)
677 : {
678 0 : struct request_queue *q = rq->q;
679 0 : struct blk_mq_ctx *ctx = rq->mq_ctx;
680 0 : struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
681 0 : const int sched_tag = rq->internal_tag;
682 :
683 0 : blk_crypto_free_request(rq);
684 0 : blk_pm_mark_last_busy(rq);
685 0 : rq->mq_hctx = NULL;
686 :
687 0 : if (rq->rq_flags & RQF_MQ_INFLIGHT)
688 : __blk_mq_dec_active_requests(hctx);
689 :
690 0 : if (rq->tag != BLK_MQ_NO_TAG)
691 0 : blk_mq_put_tag(hctx->tags, ctx, rq->tag);
692 0 : if (sched_tag != BLK_MQ_NO_TAG)
693 0 : blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
694 0 : blk_mq_sched_restart(hctx);
695 0 : blk_queue_exit(q);
696 0 : }
697 :
698 0 : void blk_mq_free_request(struct request *rq)
699 : {
700 0 : struct request_queue *q = rq->q;
701 :
702 0 : if ((rq->rq_flags & RQF_ELVPRIV) &&
703 0 : q->elevator->type->ops.finish_request)
704 0 : q->elevator->type->ops.finish_request(rq);
705 :
706 0 : if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq)))
707 0 : laptop_io_completion(q->disk->bdi);
708 :
709 0 : rq_qos_done(q, rq);
710 :
711 0 : WRITE_ONCE(rq->state, MQ_RQ_IDLE);
712 0 : if (req_ref_put_and_test(rq))
713 0 : __blk_mq_free_request(rq);
714 0 : }
715 : EXPORT_SYMBOL_GPL(blk_mq_free_request);
716 :
717 0 : void blk_mq_free_plug_rqs(struct blk_plug *plug)
718 : {
719 : struct request *rq;
720 :
721 0 : while ((rq = rq_list_pop(&plug->cached_rq)) != NULL)
722 0 : blk_mq_free_request(rq);
723 0 : }
724 :
725 0 : void blk_dump_rq_flags(struct request *rq, char *msg)
726 : {
727 0 : printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg,
728 : rq->q->disk ? rq->q->disk->disk_name : "?",
729 : (__force unsigned long long) rq->cmd_flags);
730 :
731 0 : printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
732 : (unsigned long long)blk_rq_pos(rq),
733 : blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
734 0 : printk(KERN_INFO " bio %p, biotail %p, len %u\n",
735 : rq->bio, rq->biotail, blk_rq_bytes(rq));
736 0 : }
737 : EXPORT_SYMBOL(blk_dump_rq_flags);
738 :
739 0 : static void req_bio_endio(struct request *rq, struct bio *bio,
740 : unsigned int nbytes, blk_status_t error)
741 : {
742 0 : if (unlikely(error)) {
743 0 : bio->bi_status = error;
744 0 : } else if (req_op(rq) == REQ_OP_ZONE_APPEND) {
745 : /*
746 : * Partial zone append completions cannot be supported as the
747 : * BIO fragments may end up not being written sequentially.
748 : */
749 0 : if (bio->bi_iter.bi_size != nbytes)
750 0 : bio->bi_status = BLK_STS_IOERR;
751 : else
752 0 : bio->bi_iter.bi_sector = rq->__sector;
753 : }
754 :
755 0 : bio_advance(bio, nbytes);
756 :
757 0 : if (unlikely(rq->rq_flags & RQF_QUIET))
758 : bio_set_flag(bio, BIO_QUIET);
759 : /* don't actually finish bio if it's part of flush sequence */
760 0 : if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ))
761 0 : bio_endio(bio);
762 0 : }
763 :
764 0 : static void blk_account_io_completion(struct request *req, unsigned int bytes)
765 : {
766 0 : if (req->part && blk_do_io_stat(req)) {
767 0 : const int sgrp = op_stat_group(req_op(req));
768 :
769 0 : part_stat_lock();
770 0 : part_stat_add(req->part, sectors[sgrp], bytes >> 9);
771 0 : part_stat_unlock();
772 : }
773 0 : }
774 :
775 0 : static void blk_print_req_error(struct request *req, blk_status_t status)
776 : {
777 0 : printk_ratelimited(KERN_ERR
778 : "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x "
779 : "phys_seg %u prio class %u\n",
780 : blk_status_to_str(status),
781 : req->q->disk ? req->q->disk->disk_name : "?",
782 : blk_rq_pos(req), (__force u32)req_op(req),
783 : blk_op_str(req_op(req)),
784 : (__force u32)(req->cmd_flags & ~REQ_OP_MASK),
785 : req->nr_phys_segments,
786 : IOPRIO_PRIO_CLASS(req->ioprio));
787 0 : }
788 :
789 : /*
790 : * Fully end IO on a request. Does not support partial completions, or
791 : * errors.
792 : */
793 0 : static void blk_complete_request(struct request *req)
794 : {
795 0 : const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0;
796 0 : int total_bytes = blk_rq_bytes(req);
797 0 : struct bio *bio = req->bio;
798 :
799 0 : trace_block_rq_complete(req, BLK_STS_OK, total_bytes);
800 :
801 0 : if (!bio)
802 : return;
803 :
804 : #ifdef CONFIG_BLK_DEV_INTEGRITY
805 : if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ)
806 : req->q->integrity.profile->complete_fn(req, total_bytes);
807 : #endif
808 :
809 : /*
810 : * Upper layers may call blk_crypto_evict_key() anytime after the last
811 : * bio_endio(). Therefore, the keyslot must be released before that.
812 : */
813 0 : blk_crypto_rq_put_keyslot(req);
814 :
815 0 : blk_account_io_completion(req, total_bytes);
816 :
817 : do {
818 0 : struct bio *next = bio->bi_next;
819 :
820 : /* Completion has already been traced */
821 0 : bio_clear_flag(bio, BIO_TRACE_COMPLETION);
822 :
823 0 : if (req_op(req) == REQ_OP_ZONE_APPEND)
824 0 : bio->bi_iter.bi_sector = req->__sector;
825 :
826 0 : if (!is_flush)
827 0 : bio_endio(bio);
828 0 : bio = next;
829 0 : } while (bio);
830 :
831 : /*
832 : * Reset counters so that the request stacking driver
833 : * can find how many bytes remain in the request
834 : * later.
835 : */
836 0 : if (!req->end_io) {
837 0 : req->bio = NULL;
838 0 : req->__data_len = 0;
839 : }
840 : }
841 :
842 : /**
843 : * blk_update_request - Complete multiple bytes without completing the request
844 : * @req: the request being processed
845 : * @error: block status code
846 : * @nr_bytes: number of bytes to complete for @req
847 : *
848 : * Description:
849 : * Ends I/O on a number of bytes attached to @req, but doesn't complete
850 : * the request structure even if @req doesn't have leftover.
851 : * If @req has leftover, sets it up for the next range of segments.
852 : *
853 : * Passing the result of blk_rq_bytes() as @nr_bytes guarantees
854 : * %false return from this function.
855 : *
856 : * Note:
857 : * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function
858 : * except in the consistency check at the end of this function.
859 : *
860 : * Return:
861 : * %false - this request doesn't have any more data
862 : * %true - this request has more data
863 : **/
864 0 : bool blk_update_request(struct request *req, blk_status_t error,
865 : unsigned int nr_bytes)
866 : {
867 : int total_bytes;
868 :
869 0 : trace_block_rq_complete(req, error, nr_bytes);
870 :
871 0 : if (!req->bio)
872 : return false;
873 :
874 : #ifdef CONFIG_BLK_DEV_INTEGRITY
875 : if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ &&
876 : error == BLK_STS_OK)
877 : req->q->integrity.profile->complete_fn(req, nr_bytes);
878 : #endif
879 :
880 : /*
881 : * Upper layers may call blk_crypto_evict_key() anytime after the last
882 : * bio_endio(). Therefore, the keyslot must be released before that.
883 : */
884 0 : if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req))
885 : __blk_crypto_rq_put_keyslot(req);
886 :
887 0 : if (unlikely(error && !blk_rq_is_passthrough(req) &&
888 0 : !(req->rq_flags & RQF_QUIET)) &&
889 0 : !test_bit(GD_DEAD, &req->q->disk->state)) {
890 0 : blk_print_req_error(req, error);
891 0 : trace_block_rq_error(req, error, nr_bytes);
892 : }
893 :
894 0 : blk_account_io_completion(req, nr_bytes);
895 :
896 0 : total_bytes = 0;
897 0 : while (req->bio) {
898 0 : struct bio *bio = req->bio;
899 0 : unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes);
900 :
901 0 : if (bio_bytes == bio->bi_iter.bi_size)
902 0 : req->bio = bio->bi_next;
903 :
904 : /* Completion has already been traced */
905 0 : bio_clear_flag(bio, BIO_TRACE_COMPLETION);
906 0 : req_bio_endio(req, bio, bio_bytes, error);
907 :
908 0 : total_bytes += bio_bytes;
909 0 : nr_bytes -= bio_bytes;
910 :
911 0 : if (!nr_bytes)
912 : break;
913 : }
914 :
915 : /*
916 : * completely done
917 : */
918 0 : if (!req->bio) {
919 : /*
920 : * Reset counters so that the request stacking driver
921 : * can find how many bytes remain in the request
922 : * later.
923 : */
924 0 : req->__data_len = 0;
925 0 : return false;
926 : }
927 :
928 0 : req->__data_len -= total_bytes;
929 :
930 : /* update sector only for requests with clear definition of sector */
931 0 : if (!blk_rq_is_passthrough(req))
932 0 : req->__sector += total_bytes >> 9;
933 :
934 : /* mixed attributes always follow the first bio */
935 0 : if (req->rq_flags & RQF_MIXED_MERGE) {
936 0 : req->cmd_flags &= ~REQ_FAILFAST_MASK;
937 0 : req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK;
938 : }
939 :
940 0 : if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) {
941 : /*
942 : * If total number of sectors is less than the first segment
943 : * size, something has gone terribly wrong.
944 : */
945 0 : if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
946 0 : blk_dump_rq_flags(req, "request botched");
947 0 : req->__data_len = blk_rq_cur_bytes(req);
948 : }
949 :
950 : /* recalculate the number of segments */
951 0 : req->nr_phys_segments = blk_recalc_rq_segments(req);
952 : }
953 :
954 : return true;
955 : }
956 : EXPORT_SYMBOL_GPL(blk_update_request);
957 :
958 0 : static inline void blk_account_io_done(struct request *req, u64 now)
959 : {
960 : /*
961 : * Account IO completion. flush_rq isn't accounted as a
962 : * normal IO on queueing nor completion. Accounting the
963 : * containing request is enough.
964 : */
965 0 : if (blk_do_io_stat(req) && req->part &&
966 0 : !(req->rq_flags & RQF_FLUSH_SEQ)) {
967 0 : const int sgrp = op_stat_group(req_op(req));
968 :
969 0 : part_stat_lock();
970 0 : update_io_ticks(req->part, jiffies, true);
971 0 : part_stat_inc(req->part, ios[sgrp]);
972 0 : part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
973 0 : part_stat_unlock();
974 : }
975 0 : }
976 :
977 0 : static inline void blk_account_io_start(struct request *req)
978 : {
979 0 : if (blk_do_io_stat(req)) {
980 : /*
981 : * All non-passthrough requests are created from a bio with one
982 : * exception: when a flush command that is part of a flush sequence
983 : * generated by the state machine in blk-flush.c is cloned onto the
984 : * lower device by dm-multipath we can get here without a bio.
985 : */
986 0 : if (req->bio)
987 0 : req->part = req->bio->bi_bdev;
988 : else
989 0 : req->part = req->q->disk->part0;
990 :
991 0 : part_stat_lock();
992 0 : update_io_ticks(req->part, jiffies, false);
993 0 : part_stat_unlock();
994 : }
995 0 : }
996 :
997 0 : static inline void __blk_mq_end_request_acct(struct request *rq, u64 now)
998 : {
999 0 : if (rq->rq_flags & RQF_STATS)
1000 0 : blk_stat_add(rq, now);
1001 :
1002 0 : blk_mq_sched_completed_request(rq, now);
1003 0 : blk_account_io_done(rq, now);
1004 0 : }
1005 :
1006 0 : inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
1007 : {
1008 0 : if (blk_mq_need_time_stamp(rq))
1009 0 : __blk_mq_end_request_acct(rq, ktime_get_ns());
1010 :
1011 0 : if (rq->end_io) {
1012 0 : rq_qos_done(rq->q, rq);
1013 0 : if (rq->end_io(rq, error) == RQ_END_IO_FREE)
1014 0 : blk_mq_free_request(rq);
1015 : } else {
1016 0 : blk_mq_free_request(rq);
1017 : }
1018 0 : }
1019 : EXPORT_SYMBOL(__blk_mq_end_request);
1020 :
1021 0 : void blk_mq_end_request(struct request *rq, blk_status_t error)
1022 : {
1023 0 : if (blk_update_request(rq, error, blk_rq_bytes(rq)))
1024 0 : BUG();
1025 0 : __blk_mq_end_request(rq, error);
1026 0 : }
1027 : EXPORT_SYMBOL(blk_mq_end_request);
1028 :
1029 : #define TAG_COMP_BATCH 32
1030 :
1031 0 : static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx,
1032 : int *tag_array, int nr_tags)
1033 : {
1034 0 : struct request_queue *q = hctx->queue;
1035 :
1036 : /*
1037 : * All requests should have been marked as RQF_MQ_INFLIGHT, so
1038 : * update hctx->nr_active in batch
1039 : */
1040 0 : if (hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
1041 : __blk_mq_sub_active_requests(hctx, nr_tags);
1042 :
1043 0 : blk_mq_put_tags(hctx->tags, tag_array, nr_tags);
1044 0 : percpu_ref_put_many(&q->q_usage_counter, nr_tags);
1045 0 : }
1046 :
1047 0 : void blk_mq_end_request_batch(struct io_comp_batch *iob)
1048 : {
1049 0 : int tags[TAG_COMP_BATCH], nr_tags = 0;
1050 0 : struct blk_mq_hw_ctx *cur_hctx = NULL;
1051 : struct request *rq;
1052 0 : u64 now = 0;
1053 :
1054 0 : if (iob->need_ts)
1055 0 : now = ktime_get_ns();
1056 :
1057 0 : while ((rq = rq_list_pop(&iob->req_list)) != NULL) {
1058 0 : prefetch(rq->bio);
1059 0 : prefetch(rq->rq_next);
1060 :
1061 0 : blk_complete_request(rq);
1062 0 : if (iob->need_ts)
1063 0 : __blk_mq_end_request_acct(rq, now);
1064 :
1065 0 : rq_qos_done(rq->q, rq);
1066 :
1067 : /*
1068 : * If end_io handler returns NONE, then it still has
1069 : * ownership of the request.
1070 : */
1071 0 : if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE)
1072 0 : continue;
1073 :
1074 0 : WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1075 0 : if (!req_ref_put_and_test(rq))
1076 0 : continue;
1077 :
1078 0 : blk_crypto_free_request(rq);
1079 0 : blk_pm_mark_last_busy(rq);
1080 :
1081 0 : if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) {
1082 0 : if (cur_hctx)
1083 0 : blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1084 0 : nr_tags = 0;
1085 0 : cur_hctx = rq->mq_hctx;
1086 : }
1087 0 : tags[nr_tags++] = rq->tag;
1088 : }
1089 :
1090 0 : if (nr_tags)
1091 0 : blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags);
1092 0 : }
1093 : EXPORT_SYMBOL_GPL(blk_mq_end_request_batch);
1094 :
1095 0 : static void blk_complete_reqs(struct llist_head *list)
1096 : {
1097 0 : struct llist_node *entry = llist_reverse_order(llist_del_all(list));
1098 : struct request *rq, *next;
1099 :
1100 0 : llist_for_each_entry_safe(rq, next, entry, ipi_list)
1101 0 : rq->q->mq_ops->complete(rq);
1102 0 : }
1103 :
1104 0 : static __latent_entropy void blk_done_softirq(struct softirq_action *h)
1105 : {
1106 0 : blk_complete_reqs(this_cpu_ptr(&blk_cpu_done));
1107 0 : }
1108 :
1109 0 : static int blk_softirq_cpu_dead(unsigned int cpu)
1110 : {
1111 0 : blk_complete_reqs(&per_cpu(blk_cpu_done, cpu));
1112 0 : return 0;
1113 : }
1114 :
1115 : static void __blk_mq_complete_request_remote(void *data)
1116 : {
1117 : __raise_softirq_irqoff(BLOCK_SOFTIRQ);
1118 : }
1119 :
1120 : static inline bool blk_mq_complete_need_ipi(struct request *rq)
1121 : {
1122 0 : int cpu = raw_smp_processor_id();
1123 :
1124 : if (!IS_ENABLED(CONFIG_SMP) ||
1125 : !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags))
1126 : return false;
1127 : /*
1128 : * With force threaded interrupts enabled, raising softirq from an SMP
1129 : * function call will always result in waking the ksoftirqd thread.
1130 : * This is probably worse than completing the request on a different
1131 : * cache domain.
1132 : */
1133 : if (force_irqthreads())
1134 : return false;
1135 :
1136 : /* same CPU or cache domain? Complete locally */
1137 : if (cpu == rq->mq_ctx->cpu ||
1138 : (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
1139 : cpus_share_cache(cpu, rq->mq_ctx->cpu)))
1140 : return false;
1141 :
1142 : /* don't try to IPI to an offline CPU */
1143 : return cpu_online(rq->mq_ctx->cpu);
1144 : }
1145 :
1146 : static void blk_mq_complete_send_ipi(struct request *rq)
1147 : {
1148 : struct llist_head *list;
1149 : unsigned int cpu;
1150 :
1151 : cpu = rq->mq_ctx->cpu;
1152 : list = &per_cpu(blk_cpu_done, cpu);
1153 : if (llist_add(&rq->ipi_list, list)) {
1154 : INIT_CSD(&rq->csd, __blk_mq_complete_request_remote, rq);
1155 : smp_call_function_single_async(cpu, &rq->csd);
1156 : }
1157 : }
1158 :
1159 0 : static void blk_mq_raise_softirq(struct request *rq)
1160 : {
1161 : struct llist_head *list;
1162 :
1163 0 : preempt_disable();
1164 0 : list = this_cpu_ptr(&blk_cpu_done);
1165 0 : if (llist_add(&rq->ipi_list, list))
1166 0 : raise_softirq(BLOCK_SOFTIRQ);
1167 0 : preempt_enable();
1168 0 : }
1169 :
1170 0 : bool blk_mq_complete_request_remote(struct request *rq)
1171 : {
1172 0 : WRITE_ONCE(rq->state, MQ_RQ_COMPLETE);
1173 :
1174 : /*
1175 : * For request which hctx has only one ctx mapping,
1176 : * or a polled request, always complete locally,
1177 : * it's pointless to redirect the completion.
1178 : */
1179 0 : if (rq->mq_hctx->nr_ctx == 1 ||
1180 0 : rq->cmd_flags & REQ_POLLED)
1181 : return false;
1182 :
1183 0 : if (blk_mq_complete_need_ipi(rq)) {
1184 : blk_mq_complete_send_ipi(rq);
1185 : return true;
1186 : }
1187 :
1188 0 : if (rq->q->nr_hw_queues == 1) {
1189 0 : blk_mq_raise_softirq(rq);
1190 0 : return true;
1191 : }
1192 : return false;
1193 : }
1194 : EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote);
1195 :
1196 : /**
1197 : * blk_mq_complete_request - end I/O on a request
1198 : * @rq: the request being processed
1199 : *
1200 : * Description:
1201 : * Complete a request by scheduling the ->complete_rq operation.
1202 : **/
1203 0 : void blk_mq_complete_request(struct request *rq)
1204 : {
1205 0 : if (!blk_mq_complete_request_remote(rq))
1206 0 : rq->q->mq_ops->complete(rq);
1207 0 : }
1208 : EXPORT_SYMBOL(blk_mq_complete_request);
1209 :
1210 : /**
1211 : * blk_mq_start_request - Start processing a request
1212 : * @rq: Pointer to request to be started
1213 : *
1214 : * Function used by device drivers to notify the block layer that a request
1215 : * is going to be processed now, so blk layer can do proper initializations
1216 : * such as starting the timeout timer.
1217 : */
1218 0 : void blk_mq_start_request(struct request *rq)
1219 : {
1220 0 : struct request_queue *q = rq->q;
1221 :
1222 0 : trace_block_rq_issue(rq);
1223 :
1224 0 : if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
1225 0 : rq->io_start_time_ns = ktime_get_ns();
1226 0 : rq->stats_sectors = blk_rq_sectors(rq);
1227 0 : rq->rq_flags |= RQF_STATS;
1228 0 : rq_qos_issue(q, rq);
1229 : }
1230 :
1231 0 : WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE);
1232 :
1233 0 : blk_add_timer(rq);
1234 0 : WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT);
1235 :
1236 : #ifdef CONFIG_BLK_DEV_INTEGRITY
1237 : if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE)
1238 : q->integrity.profile->prepare_fn(rq);
1239 : #endif
1240 0 : if (rq->bio && rq->bio->bi_opf & REQ_POLLED)
1241 0 : WRITE_ONCE(rq->bio->bi_cookie, blk_rq_to_qc(rq));
1242 0 : }
1243 : EXPORT_SYMBOL(blk_mq_start_request);
1244 :
1245 : /*
1246 : * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple
1247 : * queues. This is important for md arrays to benefit from merging
1248 : * requests.
1249 : */
1250 : static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug)
1251 : {
1252 0 : if (plug->multiple_queues)
1253 : return BLK_MAX_REQUEST_COUNT * 2;
1254 : return BLK_MAX_REQUEST_COUNT;
1255 : }
1256 :
1257 0 : static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq)
1258 : {
1259 0 : struct request *last = rq_list_peek(&plug->mq_list);
1260 :
1261 0 : if (!plug->rq_count) {
1262 : trace_block_plug(rq->q);
1263 0 : } else if (plug->rq_count >= blk_plug_max_rq_count(plug) ||
1264 0 : (!blk_queue_nomerges(rq->q) &&
1265 0 : blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
1266 0 : blk_mq_flush_plug_list(plug, false);
1267 0 : last = NULL;
1268 0 : trace_block_plug(rq->q);
1269 : }
1270 :
1271 0 : if (!plug->multiple_queues && last && last->q != rq->q)
1272 0 : plug->multiple_queues = true;
1273 0 : if (!plug->has_elevator && (rq->rq_flags & RQF_ELV))
1274 0 : plug->has_elevator = true;
1275 0 : rq->rq_next = NULL;
1276 0 : rq_list_add(&plug->mq_list, rq);
1277 0 : plug->rq_count++;
1278 0 : }
1279 :
1280 : /**
1281 : * blk_execute_rq_nowait - insert a request to I/O scheduler for execution
1282 : * @rq: request to insert
1283 : * @at_head: insert request at head or tail of queue
1284 : *
1285 : * Description:
1286 : * Insert a fully prepared request at the back of the I/O scheduler queue
1287 : * for execution. Don't wait for completion.
1288 : *
1289 : * Note:
1290 : * This function will invoke @done directly if the queue is dead.
1291 : */
1292 0 : void blk_execute_rq_nowait(struct request *rq, bool at_head)
1293 : {
1294 0 : struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1295 :
1296 0 : WARN_ON(irqs_disabled());
1297 0 : WARN_ON(!blk_rq_is_passthrough(rq));
1298 :
1299 0 : blk_account_io_start(rq);
1300 :
1301 : /*
1302 : * As plugging can be enabled for passthrough requests on a zoned
1303 : * device, directly accessing the plug instead of using blk_mq_plug()
1304 : * should not have any consequences.
1305 : */
1306 0 : if (current->plug && !at_head) {
1307 0 : blk_add_rq_to_plug(current->plug, rq);
1308 0 : return;
1309 : }
1310 :
1311 0 : blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1312 0 : blk_mq_run_hw_queue(hctx, false);
1313 : }
1314 : EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
1315 :
1316 : struct blk_rq_wait {
1317 : struct completion done;
1318 : blk_status_t ret;
1319 : };
1320 :
1321 0 : static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret)
1322 : {
1323 0 : struct blk_rq_wait *wait = rq->end_io_data;
1324 :
1325 0 : wait->ret = ret;
1326 0 : complete(&wait->done);
1327 0 : return RQ_END_IO_NONE;
1328 : }
1329 :
1330 0 : bool blk_rq_is_poll(struct request *rq)
1331 : {
1332 0 : if (!rq->mq_hctx)
1333 : return false;
1334 0 : if (rq->mq_hctx->type != HCTX_TYPE_POLL)
1335 : return false;
1336 0 : return true;
1337 : }
1338 : EXPORT_SYMBOL_GPL(blk_rq_is_poll);
1339 :
1340 0 : static void blk_rq_poll_completion(struct request *rq, struct completion *wait)
1341 : {
1342 : do {
1343 0 : blk_mq_poll(rq->q, blk_rq_to_qc(rq), NULL, 0);
1344 0 : cond_resched();
1345 0 : } while (!completion_done(wait));
1346 0 : }
1347 :
1348 : /**
1349 : * blk_execute_rq - insert a request into queue for execution
1350 : * @rq: request to insert
1351 : * @at_head: insert request at head or tail of queue
1352 : *
1353 : * Description:
1354 : * Insert a fully prepared request at the back of the I/O scheduler queue
1355 : * for execution and wait for completion.
1356 : * Return: The blk_status_t result provided to blk_mq_end_request().
1357 : */
1358 0 : blk_status_t blk_execute_rq(struct request *rq, bool at_head)
1359 : {
1360 0 : struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1361 0 : struct blk_rq_wait wait = {
1362 0 : .done = COMPLETION_INITIALIZER_ONSTACK(wait.done),
1363 : };
1364 :
1365 0 : WARN_ON(irqs_disabled());
1366 0 : WARN_ON(!blk_rq_is_passthrough(rq));
1367 :
1368 0 : rq->end_io_data = &wait;
1369 0 : rq->end_io = blk_end_sync_rq;
1370 :
1371 0 : blk_account_io_start(rq);
1372 0 : blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0);
1373 0 : blk_mq_run_hw_queue(hctx, false);
1374 :
1375 0 : if (blk_rq_is_poll(rq)) {
1376 0 : blk_rq_poll_completion(rq, &wait.done);
1377 : } else {
1378 : /*
1379 : * Prevent hang_check timer from firing at us during very long
1380 : * I/O
1381 : */
1382 0 : unsigned long hang_check = sysctl_hung_task_timeout_secs;
1383 :
1384 : if (hang_check)
1385 : while (!wait_for_completion_io_timeout(&wait.done,
1386 : hang_check * (HZ/2)))
1387 : ;
1388 : else
1389 0 : wait_for_completion_io(&wait.done);
1390 : }
1391 :
1392 0 : return wait.ret;
1393 : }
1394 : EXPORT_SYMBOL(blk_execute_rq);
1395 :
1396 0 : static void __blk_mq_requeue_request(struct request *rq)
1397 : {
1398 0 : struct request_queue *q = rq->q;
1399 :
1400 0 : blk_mq_put_driver_tag(rq);
1401 :
1402 0 : trace_block_rq_requeue(rq);
1403 0 : rq_qos_requeue(q, rq);
1404 :
1405 0 : if (blk_mq_request_started(rq)) {
1406 0 : WRITE_ONCE(rq->state, MQ_RQ_IDLE);
1407 0 : rq->rq_flags &= ~RQF_TIMED_OUT;
1408 : }
1409 0 : }
1410 :
1411 0 : void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
1412 : {
1413 0 : struct request_queue *q = rq->q;
1414 :
1415 0 : __blk_mq_requeue_request(rq);
1416 :
1417 : /* this request will be re-inserted to io scheduler queue */
1418 0 : blk_mq_sched_requeue_request(rq);
1419 :
1420 0 : blk_mq_add_to_requeue_list(rq, BLK_MQ_INSERT_AT_HEAD);
1421 :
1422 0 : if (kick_requeue_list)
1423 : blk_mq_kick_requeue_list(q);
1424 0 : }
1425 : EXPORT_SYMBOL(blk_mq_requeue_request);
1426 :
1427 0 : static void blk_mq_requeue_work(struct work_struct *work)
1428 : {
1429 0 : struct request_queue *q =
1430 0 : container_of(work, struct request_queue, requeue_work.work);
1431 0 : LIST_HEAD(rq_list);
1432 : struct request *rq, *next;
1433 :
1434 0 : spin_lock_irq(&q->requeue_lock);
1435 0 : list_splice_init(&q->requeue_list, &rq_list);
1436 0 : spin_unlock_irq(&q->requeue_lock);
1437 :
1438 0 : list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
1439 : /*
1440 : * If RQF_DONTPREP ist set, the request has been started by the
1441 : * driver already and might have driver-specific data allocated
1442 : * already. Insert it into the hctx dispatch list to avoid
1443 : * block layer merges for the request.
1444 : */
1445 0 : if (rq->rq_flags & RQF_DONTPREP) {
1446 0 : rq->rq_flags &= ~RQF_SOFTBARRIER;
1447 0 : list_del_init(&rq->queuelist);
1448 : blk_mq_request_bypass_insert(rq, 0);
1449 0 : } else if (rq->rq_flags & RQF_SOFTBARRIER) {
1450 0 : rq->rq_flags &= ~RQF_SOFTBARRIER;
1451 0 : list_del_init(&rq->queuelist);
1452 0 : blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD);
1453 : }
1454 : }
1455 :
1456 0 : while (!list_empty(&rq_list)) {
1457 0 : rq = list_entry(rq_list.next, struct request, queuelist);
1458 0 : list_del_init(&rq->queuelist);
1459 0 : blk_mq_insert_request(rq, 0);
1460 : }
1461 :
1462 0 : blk_mq_run_hw_queues(q, false);
1463 0 : }
1464 :
1465 0 : void blk_mq_add_to_requeue_list(struct request *rq, blk_insert_t insert_flags)
1466 : {
1467 0 : struct request_queue *q = rq->q;
1468 : unsigned long flags;
1469 :
1470 : /*
1471 : * We abuse this flag that is otherwise used by the I/O scheduler to
1472 : * request head insertion from the workqueue.
1473 : */
1474 0 : BUG_ON(rq->rq_flags & RQF_SOFTBARRIER);
1475 :
1476 0 : spin_lock_irqsave(&q->requeue_lock, flags);
1477 0 : if (insert_flags & BLK_MQ_INSERT_AT_HEAD) {
1478 0 : rq->rq_flags |= RQF_SOFTBARRIER;
1479 0 : list_add(&rq->queuelist, &q->requeue_list);
1480 : } else {
1481 0 : list_add_tail(&rq->queuelist, &q->requeue_list);
1482 : }
1483 0 : spin_unlock_irqrestore(&q->requeue_lock, flags);
1484 0 : }
1485 :
1486 0 : void blk_mq_kick_requeue_list(struct request_queue *q)
1487 : {
1488 0 : kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0);
1489 0 : }
1490 : EXPORT_SYMBOL(blk_mq_kick_requeue_list);
1491 :
1492 0 : void blk_mq_delay_kick_requeue_list(struct request_queue *q,
1493 : unsigned long msecs)
1494 : {
1495 0 : kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work,
1496 : msecs_to_jiffies(msecs));
1497 0 : }
1498 : EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
1499 :
1500 0 : static bool blk_mq_rq_inflight(struct request *rq, void *priv)
1501 : {
1502 : /*
1503 : * If we find a request that isn't idle we know the queue is busy
1504 : * as it's checked in the iter.
1505 : * Return false to stop the iteration.
1506 : */
1507 0 : if (blk_mq_request_started(rq)) {
1508 0 : bool *busy = priv;
1509 :
1510 0 : *busy = true;
1511 0 : return false;
1512 : }
1513 :
1514 : return true;
1515 : }
1516 :
1517 0 : bool blk_mq_queue_inflight(struct request_queue *q)
1518 : {
1519 0 : bool busy = false;
1520 :
1521 0 : blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy);
1522 0 : return busy;
1523 : }
1524 : EXPORT_SYMBOL_GPL(blk_mq_queue_inflight);
1525 :
1526 0 : static void blk_mq_rq_timed_out(struct request *req)
1527 : {
1528 0 : req->rq_flags |= RQF_TIMED_OUT;
1529 0 : if (req->q->mq_ops->timeout) {
1530 : enum blk_eh_timer_return ret;
1531 :
1532 0 : ret = req->q->mq_ops->timeout(req);
1533 0 : if (ret == BLK_EH_DONE)
1534 : return;
1535 0 : WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER);
1536 : }
1537 :
1538 0 : blk_add_timer(req);
1539 : }
1540 :
1541 : struct blk_expired_data {
1542 : bool has_timedout_rq;
1543 : unsigned long next;
1544 : unsigned long timeout_start;
1545 : };
1546 :
1547 : static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired)
1548 : {
1549 : unsigned long deadline;
1550 :
1551 0 : if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT)
1552 : return false;
1553 0 : if (rq->rq_flags & RQF_TIMED_OUT)
1554 : return false;
1555 :
1556 0 : deadline = READ_ONCE(rq->deadline);
1557 0 : if (time_after_eq(expired->timeout_start, deadline))
1558 : return true;
1559 :
1560 0 : if (expired->next == 0)
1561 0 : expired->next = deadline;
1562 0 : else if (time_after(expired->next, deadline))
1563 0 : expired->next = deadline;
1564 : return false;
1565 : }
1566 :
1567 0 : void blk_mq_put_rq_ref(struct request *rq)
1568 : {
1569 0 : if (is_flush_rq(rq)) {
1570 0 : if (rq->end_io(rq, 0) == RQ_END_IO_FREE)
1571 0 : blk_mq_free_request(rq);
1572 0 : } else if (req_ref_put_and_test(rq)) {
1573 0 : __blk_mq_free_request(rq);
1574 : }
1575 0 : }
1576 :
1577 0 : static bool blk_mq_check_expired(struct request *rq, void *priv)
1578 : {
1579 0 : struct blk_expired_data *expired = priv;
1580 :
1581 : /*
1582 : * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot
1583 : * be reallocated underneath the timeout handler's processing, then
1584 : * the expire check is reliable. If the request is not expired, then
1585 : * it was completed and reallocated as a new request after returning
1586 : * from blk_mq_check_expired().
1587 : */
1588 0 : if (blk_mq_req_expired(rq, expired)) {
1589 0 : expired->has_timedout_rq = true;
1590 0 : return false;
1591 : }
1592 : return true;
1593 : }
1594 :
1595 0 : static bool blk_mq_handle_expired(struct request *rq, void *priv)
1596 : {
1597 0 : struct blk_expired_data *expired = priv;
1598 :
1599 0 : if (blk_mq_req_expired(rq, expired))
1600 0 : blk_mq_rq_timed_out(rq);
1601 0 : return true;
1602 : }
1603 :
1604 0 : static void blk_mq_timeout_work(struct work_struct *work)
1605 : {
1606 0 : struct request_queue *q =
1607 0 : container_of(work, struct request_queue, timeout_work);
1608 0 : struct blk_expired_data expired = {
1609 : .timeout_start = jiffies,
1610 : };
1611 : struct blk_mq_hw_ctx *hctx;
1612 : unsigned long i;
1613 :
1614 : /* A deadlock might occur if a request is stuck requiring a
1615 : * timeout at the same time a queue freeze is waiting
1616 : * completion, since the timeout code would not be able to
1617 : * acquire the queue reference here.
1618 : *
1619 : * That's why we don't use blk_queue_enter here; instead, we use
1620 : * percpu_ref_tryget directly, because we need to be able to
1621 : * obtain a reference even in the short window between the queue
1622 : * starting to freeze, by dropping the first reference in
1623 : * blk_freeze_queue_start, and the moment the last request is
1624 : * consumed, marked by the instant q_usage_counter reaches
1625 : * zero.
1626 : */
1627 0 : if (!percpu_ref_tryget(&q->q_usage_counter))
1628 0 : return;
1629 :
1630 : /* check if there is any timed-out request */
1631 0 : blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired);
1632 0 : if (expired.has_timedout_rq) {
1633 : /*
1634 : * Before walking tags, we must ensure any submit started
1635 : * before the current time has finished. Since the submit
1636 : * uses srcu or rcu, wait for a synchronization point to
1637 : * ensure all running submits have finished
1638 : */
1639 0 : blk_mq_wait_quiesce_done(q->tag_set);
1640 :
1641 0 : expired.next = 0;
1642 0 : blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired);
1643 : }
1644 :
1645 0 : if (expired.next != 0) {
1646 0 : mod_timer(&q->timeout, expired.next);
1647 : } else {
1648 : /*
1649 : * Request timeouts are handled as a forward rolling timer. If
1650 : * we end up here it means that no requests are pending and
1651 : * also that no request has been pending for a while. Mark
1652 : * each hctx as idle.
1653 : */
1654 0 : queue_for_each_hw_ctx(q, hctx, i) {
1655 : /* the hctx may be unmapped, so check it here */
1656 0 : if (blk_mq_hw_queue_mapped(hctx))
1657 : blk_mq_tag_idle(hctx);
1658 : }
1659 : }
1660 0 : blk_queue_exit(q);
1661 : }
1662 :
1663 : struct flush_busy_ctx_data {
1664 : struct blk_mq_hw_ctx *hctx;
1665 : struct list_head *list;
1666 : };
1667 :
1668 0 : static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
1669 : {
1670 0 : struct flush_busy_ctx_data *flush_data = data;
1671 0 : struct blk_mq_hw_ctx *hctx = flush_data->hctx;
1672 0 : struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1673 0 : enum hctx_type type = hctx->type;
1674 :
1675 0 : spin_lock(&ctx->lock);
1676 0 : list_splice_tail_init(&ctx->rq_lists[type], flush_data->list);
1677 0 : sbitmap_clear_bit(sb, bitnr);
1678 0 : spin_unlock(&ctx->lock);
1679 0 : return true;
1680 : }
1681 :
1682 : /*
1683 : * Process software queues that have been marked busy, splicing them
1684 : * to the for-dispatch
1685 : */
1686 0 : void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
1687 : {
1688 0 : struct flush_busy_ctx_data data = {
1689 : .hctx = hctx,
1690 : .list = list,
1691 : };
1692 :
1693 0 : sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
1694 0 : }
1695 : EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
1696 :
1697 : struct dispatch_rq_data {
1698 : struct blk_mq_hw_ctx *hctx;
1699 : struct request *rq;
1700 : };
1701 :
1702 0 : static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr,
1703 : void *data)
1704 : {
1705 0 : struct dispatch_rq_data *dispatch_data = data;
1706 0 : struct blk_mq_hw_ctx *hctx = dispatch_data->hctx;
1707 0 : struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
1708 0 : enum hctx_type type = hctx->type;
1709 :
1710 0 : spin_lock(&ctx->lock);
1711 0 : if (!list_empty(&ctx->rq_lists[type])) {
1712 0 : dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next);
1713 0 : list_del_init(&dispatch_data->rq->queuelist);
1714 0 : if (list_empty(&ctx->rq_lists[type]))
1715 : sbitmap_clear_bit(sb, bitnr);
1716 : }
1717 0 : spin_unlock(&ctx->lock);
1718 :
1719 0 : return !dispatch_data->rq;
1720 : }
1721 :
1722 0 : struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
1723 : struct blk_mq_ctx *start)
1724 : {
1725 0 : unsigned off = start ? start->index_hw[hctx->type] : 0;
1726 0 : struct dispatch_rq_data data = {
1727 : .hctx = hctx,
1728 : .rq = NULL,
1729 : };
1730 :
1731 0 : __sbitmap_for_each_set(&hctx->ctx_map, off,
1732 : dispatch_rq_from_ctx, &data);
1733 :
1734 0 : return data.rq;
1735 : }
1736 :
1737 0 : static bool __blk_mq_alloc_driver_tag(struct request *rq)
1738 : {
1739 0 : struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
1740 0 : unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags;
1741 : int tag;
1742 :
1743 0 : blk_mq_tag_busy(rq->mq_hctx);
1744 :
1745 0 : if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) {
1746 0 : bt = &rq->mq_hctx->tags->breserved_tags;
1747 0 : tag_offset = 0;
1748 : } else {
1749 0 : if (!hctx_may_queue(rq->mq_hctx, bt))
1750 : return false;
1751 : }
1752 :
1753 0 : tag = __sbitmap_queue_get(bt);
1754 0 : if (tag == BLK_MQ_NO_TAG)
1755 : return false;
1756 :
1757 0 : rq->tag = tag + tag_offset;
1758 0 : return true;
1759 : }
1760 :
1761 0 : bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx *hctx, struct request *rq)
1762 : {
1763 0 : if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_alloc_driver_tag(rq))
1764 : return false;
1765 :
1766 0 : if ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
1767 0 : !(rq->rq_flags & RQF_MQ_INFLIGHT)) {
1768 0 : rq->rq_flags |= RQF_MQ_INFLIGHT;
1769 : __blk_mq_inc_active_requests(hctx);
1770 : }
1771 0 : hctx->tags->rqs[rq->tag] = rq;
1772 0 : return true;
1773 : }
1774 :
1775 0 : static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode,
1776 : int flags, void *key)
1777 : {
1778 : struct blk_mq_hw_ctx *hctx;
1779 :
1780 0 : hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
1781 :
1782 0 : spin_lock(&hctx->dispatch_wait_lock);
1783 0 : if (!list_empty(&wait->entry)) {
1784 : struct sbitmap_queue *sbq;
1785 :
1786 0 : list_del_init(&wait->entry);
1787 0 : sbq = &hctx->tags->bitmap_tags;
1788 0 : atomic_dec(&sbq->ws_active);
1789 : }
1790 0 : spin_unlock(&hctx->dispatch_wait_lock);
1791 :
1792 0 : blk_mq_run_hw_queue(hctx, true);
1793 0 : return 1;
1794 : }
1795 :
1796 : /*
1797 : * Mark us waiting for a tag. For shared tags, this involves hooking us into
1798 : * the tag wakeups. For non-shared tags, we can simply mark us needing a
1799 : * restart. For both cases, take care to check the condition again after
1800 : * marking us as waiting.
1801 : */
1802 0 : static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx,
1803 : struct request *rq)
1804 : {
1805 : struct sbitmap_queue *sbq;
1806 : struct wait_queue_head *wq;
1807 : wait_queue_entry_t *wait;
1808 : bool ret;
1809 :
1810 0 : if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) &&
1811 0 : !(blk_mq_is_shared_tags(hctx->flags))) {
1812 0 : blk_mq_sched_mark_restart_hctx(hctx);
1813 :
1814 : /*
1815 : * It's possible that a tag was freed in the window between the
1816 : * allocation failure and adding the hardware queue to the wait
1817 : * queue.
1818 : *
1819 : * Don't clear RESTART here, someone else could have set it.
1820 : * At most this will cost an extra queue run.
1821 : */
1822 0 : return blk_mq_get_driver_tag(rq);
1823 : }
1824 :
1825 0 : wait = &hctx->dispatch_wait;
1826 0 : if (!list_empty_careful(&wait->entry))
1827 : return false;
1828 :
1829 0 : if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag))
1830 0 : sbq = &hctx->tags->breserved_tags;
1831 : else
1832 0 : sbq = &hctx->tags->bitmap_tags;
1833 0 : wq = &bt_wait_ptr(sbq, hctx)->wait;
1834 :
1835 0 : spin_lock_irq(&wq->lock);
1836 0 : spin_lock(&hctx->dispatch_wait_lock);
1837 0 : if (!list_empty(&wait->entry)) {
1838 0 : spin_unlock(&hctx->dispatch_wait_lock);
1839 0 : spin_unlock_irq(&wq->lock);
1840 0 : return false;
1841 : }
1842 :
1843 0 : atomic_inc(&sbq->ws_active);
1844 0 : wait->flags &= ~WQ_FLAG_EXCLUSIVE;
1845 0 : __add_wait_queue(wq, wait);
1846 :
1847 : /*
1848 : * It's possible that a tag was freed in the window between the
1849 : * allocation failure and adding the hardware queue to the wait
1850 : * queue.
1851 : */
1852 0 : ret = blk_mq_get_driver_tag(rq);
1853 0 : if (!ret) {
1854 0 : spin_unlock(&hctx->dispatch_wait_lock);
1855 0 : spin_unlock_irq(&wq->lock);
1856 0 : return false;
1857 : }
1858 :
1859 : /*
1860 : * We got a tag, remove ourselves from the wait queue to ensure
1861 : * someone else gets the wakeup.
1862 : */
1863 0 : list_del_init(&wait->entry);
1864 0 : atomic_dec(&sbq->ws_active);
1865 0 : spin_unlock(&hctx->dispatch_wait_lock);
1866 0 : spin_unlock_irq(&wq->lock);
1867 :
1868 0 : return true;
1869 : }
1870 :
1871 : #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8
1872 : #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4
1873 : /*
1874 : * Update dispatch busy with the Exponential Weighted Moving Average(EWMA):
1875 : * - EWMA is one simple way to compute running average value
1876 : * - weight(7/8 and 1/8) is applied so that it can decrease exponentially
1877 : * - take 4 as factor for avoiding to get too small(0) result, and this
1878 : * factor doesn't matter because EWMA decreases exponentially
1879 : */
1880 : static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy)
1881 : {
1882 : unsigned int ewma;
1883 :
1884 0 : ewma = hctx->dispatch_busy;
1885 :
1886 0 : if (!ewma && !busy)
1887 : return;
1888 :
1889 0 : ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1;
1890 : if (busy)
1891 0 : ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR;
1892 0 : ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT;
1893 :
1894 0 : hctx->dispatch_busy = ewma;
1895 : }
1896 :
1897 : #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */
1898 :
1899 : static void blk_mq_handle_dev_resource(struct request *rq,
1900 : struct list_head *list)
1901 : {
1902 0 : list_add(&rq->queuelist, list);
1903 0 : __blk_mq_requeue_request(rq);
1904 : }
1905 :
1906 : static void blk_mq_handle_zone_resource(struct request *rq,
1907 : struct list_head *zone_list)
1908 : {
1909 : /*
1910 : * If we end up here it is because we cannot dispatch a request to a
1911 : * specific zone due to LLD level zone-write locking or other zone
1912 : * related resource not being available. In this case, set the request
1913 : * aside in zone_list for retrying it later.
1914 : */
1915 0 : list_add(&rq->queuelist, zone_list);
1916 0 : __blk_mq_requeue_request(rq);
1917 : }
1918 :
1919 : enum prep_dispatch {
1920 : PREP_DISPATCH_OK,
1921 : PREP_DISPATCH_NO_TAG,
1922 : PREP_DISPATCH_NO_BUDGET,
1923 : };
1924 :
1925 0 : static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq,
1926 : bool need_budget)
1927 : {
1928 0 : struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
1929 0 : int budget_token = -1;
1930 :
1931 0 : if (need_budget) {
1932 0 : budget_token = blk_mq_get_dispatch_budget(rq->q);
1933 0 : if (budget_token < 0) {
1934 : blk_mq_put_driver_tag(rq);
1935 : return PREP_DISPATCH_NO_BUDGET;
1936 : }
1937 : blk_mq_set_rq_budget_token(rq, budget_token);
1938 : }
1939 :
1940 0 : if (!blk_mq_get_driver_tag(rq)) {
1941 : /*
1942 : * The initial allocation attempt failed, so we need to
1943 : * rerun the hardware queue when a tag is freed. The
1944 : * waitqueue takes care of that. If the queue is run
1945 : * before we add this entry back on the dispatch list,
1946 : * we'll re-run it below.
1947 : */
1948 0 : if (!blk_mq_mark_tag_wait(hctx, rq)) {
1949 : /*
1950 : * All budgets not got from this function will be put
1951 : * together during handling partial dispatch
1952 : */
1953 0 : if (need_budget)
1954 0 : blk_mq_put_dispatch_budget(rq->q, budget_token);
1955 : return PREP_DISPATCH_NO_TAG;
1956 : }
1957 : }
1958 :
1959 : return PREP_DISPATCH_OK;
1960 : }
1961 :
1962 : /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */
1963 0 : static void blk_mq_release_budgets(struct request_queue *q,
1964 : struct list_head *list)
1965 : {
1966 : struct request *rq;
1967 :
1968 0 : list_for_each_entry(rq, list, queuelist) {
1969 0 : int budget_token = blk_mq_get_rq_budget_token(rq);
1970 :
1971 0 : if (budget_token >= 0)
1972 : blk_mq_put_dispatch_budget(q, budget_token);
1973 : }
1974 0 : }
1975 :
1976 : /*
1977 : * blk_mq_commit_rqs will notify driver using bd->last that there is no
1978 : * more requests. (See comment in struct blk_mq_ops for commit_rqs for
1979 : * details)
1980 : * Attention, we should explicitly call this in unusual cases:
1981 : * 1) did not queue everything initially scheduled to queue
1982 : * 2) the last attempt to queue a request failed
1983 : */
1984 : static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued,
1985 : bool from_schedule)
1986 : {
1987 0 : if (hctx->queue->mq_ops->commit_rqs && queued) {
1988 0 : trace_block_unplug(hctx->queue, queued, !from_schedule);
1989 0 : hctx->queue->mq_ops->commit_rqs(hctx);
1990 : }
1991 : }
1992 :
1993 : /*
1994 : * Returns true if we did some work AND can potentially do more.
1995 : */
1996 0 : bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
1997 : unsigned int nr_budgets)
1998 : {
1999 : enum prep_dispatch prep;
2000 0 : struct request_queue *q = hctx->queue;
2001 : struct request *rq;
2002 : int queued;
2003 0 : blk_status_t ret = BLK_STS_OK;
2004 0 : LIST_HEAD(zone_list);
2005 0 : bool needs_resource = false;
2006 :
2007 0 : if (list_empty(list))
2008 : return false;
2009 :
2010 : /*
2011 : * Now process all the entries, sending them to the driver.
2012 : */
2013 : queued = 0;
2014 : do {
2015 : struct blk_mq_queue_data bd;
2016 :
2017 0 : rq = list_first_entry(list, struct request, queuelist);
2018 :
2019 0 : WARN_ON_ONCE(hctx != rq->mq_hctx);
2020 0 : prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets);
2021 0 : if (prep != PREP_DISPATCH_OK)
2022 : break;
2023 :
2024 0 : list_del_init(&rq->queuelist);
2025 :
2026 0 : bd.rq = rq;
2027 0 : bd.last = list_empty(list);
2028 :
2029 : /*
2030 : * once the request is queued to lld, no need to cover the
2031 : * budget any more
2032 : */
2033 0 : if (nr_budgets)
2034 0 : nr_budgets--;
2035 0 : ret = q->mq_ops->queue_rq(hctx, &bd);
2036 0 : switch (ret) {
2037 : case BLK_STS_OK:
2038 0 : queued++;
2039 0 : break;
2040 : case BLK_STS_RESOURCE:
2041 0 : needs_resource = true;
2042 : fallthrough;
2043 : case BLK_STS_DEV_RESOURCE:
2044 0 : blk_mq_handle_dev_resource(rq, list);
2045 0 : goto out;
2046 : case BLK_STS_ZONE_RESOURCE:
2047 : /*
2048 : * Move the request to zone_list and keep going through
2049 : * the dispatch list to find more requests the drive can
2050 : * accept.
2051 : */
2052 0 : blk_mq_handle_zone_resource(rq, &zone_list);
2053 0 : needs_resource = true;
2054 0 : break;
2055 : default:
2056 0 : blk_mq_end_request(rq, ret);
2057 : }
2058 0 : } while (!list_empty(list));
2059 : out:
2060 0 : if (!list_empty(&zone_list))
2061 : list_splice_tail_init(&zone_list, list);
2062 :
2063 : /* If we didn't flush the entire list, we could have told the driver
2064 : * there was more coming, but that turned out to be a lie.
2065 : */
2066 0 : if (!list_empty(list) || ret != BLK_STS_OK)
2067 : blk_mq_commit_rqs(hctx, queued, false);
2068 :
2069 : /*
2070 : * Any items that need requeuing? Stuff them into hctx->dispatch,
2071 : * that is where we will continue on next queue run.
2072 : */
2073 0 : if (!list_empty(list)) {
2074 : bool needs_restart;
2075 : /* For non-shared tags, the RESTART check will suffice */
2076 0 : bool no_tag = prep == PREP_DISPATCH_NO_TAG &&
2077 0 : ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) ||
2078 0 : blk_mq_is_shared_tags(hctx->flags));
2079 :
2080 0 : if (nr_budgets)
2081 0 : blk_mq_release_budgets(q, list);
2082 :
2083 0 : spin_lock(&hctx->lock);
2084 0 : list_splice_tail_init(list, &hctx->dispatch);
2085 0 : spin_unlock(&hctx->lock);
2086 :
2087 : /*
2088 : * Order adding requests to hctx->dispatch and checking
2089 : * SCHED_RESTART flag. The pair of this smp_mb() is the one
2090 : * in blk_mq_sched_restart(). Avoid restart code path to
2091 : * miss the new added requests to hctx->dispatch, meantime
2092 : * SCHED_RESTART is observed here.
2093 : */
2094 0 : smp_mb();
2095 :
2096 : /*
2097 : * If SCHED_RESTART was set by the caller of this function and
2098 : * it is no longer set that means that it was cleared by another
2099 : * thread and hence that a queue rerun is needed.
2100 : *
2101 : * If 'no_tag' is set, that means that we failed getting
2102 : * a driver tag with an I/O scheduler attached. If our dispatch
2103 : * waitqueue is no longer active, ensure that we run the queue
2104 : * AFTER adding our entries back to the list.
2105 : *
2106 : * If no I/O scheduler has been configured it is possible that
2107 : * the hardware queue got stopped and restarted before requests
2108 : * were pushed back onto the dispatch list. Rerun the queue to
2109 : * avoid starvation. Notes:
2110 : * - blk_mq_run_hw_queue() checks whether or not a queue has
2111 : * been stopped before rerunning a queue.
2112 : * - Some but not all block drivers stop a queue before
2113 : * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq
2114 : * and dm-rq.
2115 : *
2116 : * If driver returns BLK_STS_RESOURCE and SCHED_RESTART
2117 : * bit is set, run queue after a delay to avoid IO stalls
2118 : * that could otherwise occur if the queue is idle. We'll do
2119 : * similar if we couldn't get budget or couldn't lock a zone
2120 : * and SCHED_RESTART is set.
2121 : */
2122 0 : needs_restart = blk_mq_sched_needs_restart(hctx);
2123 0 : if (prep == PREP_DISPATCH_NO_BUDGET)
2124 0 : needs_resource = true;
2125 0 : if (!needs_restart ||
2126 0 : (no_tag && list_empty_careful(&hctx->dispatch_wait.entry)))
2127 0 : blk_mq_run_hw_queue(hctx, true);
2128 0 : else if (needs_resource)
2129 0 : blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY);
2130 :
2131 0 : blk_mq_update_dispatch_busy(hctx, true);
2132 0 : return false;
2133 : }
2134 :
2135 : blk_mq_update_dispatch_busy(hctx, false);
2136 : return true;
2137 : }
2138 :
2139 0 : static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx)
2140 : {
2141 0 : int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask);
2142 :
2143 0 : if (cpu >= nr_cpu_ids)
2144 0 : cpu = cpumask_first(hctx->cpumask);
2145 0 : return cpu;
2146 : }
2147 :
2148 : /*
2149 : * It'd be great if the workqueue API had a way to pass
2150 : * in a mask and had some smarts for more clever placement.
2151 : * For now we just round-robin here, switching for every
2152 : * BLK_MQ_CPU_WORK_BATCH queued items.
2153 : */
2154 0 : static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
2155 : {
2156 0 : bool tried = false;
2157 0 : int next_cpu = hctx->next_cpu;
2158 :
2159 0 : if (hctx->queue->nr_hw_queues == 1)
2160 : return WORK_CPU_UNBOUND;
2161 :
2162 0 : if (--hctx->next_cpu_batch <= 0) {
2163 : select_cpu:
2164 0 : next_cpu = cpumask_next_and(next_cpu, hctx->cpumask,
2165 : cpu_online_mask);
2166 0 : if (next_cpu >= nr_cpu_ids)
2167 0 : next_cpu = blk_mq_first_mapped_cpu(hctx);
2168 0 : hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
2169 : }
2170 :
2171 : /*
2172 : * Do unbound schedule if we can't find a online CPU for this hctx,
2173 : * and it should only happen in the path of handling CPU DEAD.
2174 : */
2175 0 : if (!cpu_online(next_cpu)) {
2176 0 : if (!tried) {
2177 : tried = true;
2178 : goto select_cpu;
2179 : }
2180 :
2181 : /*
2182 : * Make sure to re-select CPU next time once after CPUs
2183 : * in hctx->cpumask become online again.
2184 : */
2185 0 : hctx->next_cpu = next_cpu;
2186 0 : hctx->next_cpu_batch = 1;
2187 0 : return WORK_CPU_UNBOUND;
2188 : }
2189 :
2190 0 : hctx->next_cpu = next_cpu;
2191 0 : return next_cpu;
2192 : }
2193 :
2194 : /**
2195 : * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously.
2196 : * @hctx: Pointer to the hardware queue to run.
2197 : * @msecs: Milliseconds of delay to wait before running the queue.
2198 : *
2199 : * Run a hardware queue asynchronously with a delay of @msecs.
2200 : */
2201 0 : void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
2202 : {
2203 0 : if (unlikely(blk_mq_hctx_stopped(hctx)))
2204 : return;
2205 0 : kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work,
2206 : msecs_to_jiffies(msecs));
2207 : }
2208 : EXPORT_SYMBOL(blk_mq_delay_run_hw_queue);
2209 :
2210 : /**
2211 : * blk_mq_run_hw_queue - Start to run a hardware queue.
2212 : * @hctx: Pointer to the hardware queue to run.
2213 : * @async: If we want to run the queue asynchronously.
2214 : *
2215 : * Check if the request queue is not in a quiesced state and if there are
2216 : * pending requests to be sent. If this is true, run the queue to send requests
2217 : * to hardware.
2218 : */
2219 0 : void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2220 : {
2221 : bool need_run;
2222 :
2223 : /*
2224 : * We can't run the queue inline with interrupts disabled.
2225 : */
2226 0 : WARN_ON_ONCE(!async && in_interrupt());
2227 :
2228 : /*
2229 : * When queue is quiesced, we may be switching io scheduler, or
2230 : * updating nr_hw_queues, or other things, and we can't run queue
2231 : * any more, even __blk_mq_hctx_has_pending() can't be called safely.
2232 : *
2233 : * And queue will be rerun in blk_mq_unquiesce_queue() if it is
2234 : * quiesced.
2235 : */
2236 0 : __blk_mq_run_dispatch_ops(hctx->queue, false,
2237 : need_run = !blk_queue_quiesced(hctx->queue) &&
2238 : blk_mq_hctx_has_pending(hctx));
2239 :
2240 0 : if (!need_run)
2241 : return;
2242 :
2243 0 : if (async || (hctx->flags & BLK_MQ_F_BLOCKING) ||
2244 0 : !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) {
2245 0 : blk_mq_delay_run_hw_queue(hctx, 0);
2246 0 : return;
2247 : }
2248 :
2249 0 : blk_mq_run_dispatch_ops(hctx->queue,
2250 : blk_mq_sched_dispatch_requests(hctx));
2251 : }
2252 : EXPORT_SYMBOL(blk_mq_run_hw_queue);
2253 :
2254 : /*
2255 : * Return prefered queue to dispatch from (if any) for non-mq aware IO
2256 : * scheduler.
2257 : */
2258 : static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
2259 : {
2260 0 : struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
2261 : /*
2262 : * If the IO scheduler does not respect hardware queues when
2263 : * dispatching, we just don't bother with multiple HW queues and
2264 : * dispatch from hctx for the current CPU since running multiple queues
2265 : * just causes lock contention inside the scheduler and pointless cache
2266 : * bouncing.
2267 : */
2268 0 : struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT];
2269 :
2270 0 : if (!blk_mq_hctx_stopped(hctx))
2271 : return hctx;
2272 : return NULL;
2273 : }
2274 :
2275 : /**
2276 : * blk_mq_run_hw_queues - Run all hardware queues in a request queue.
2277 : * @q: Pointer to the request queue to run.
2278 : * @async: If we want to run the queue asynchronously.
2279 : */
2280 0 : void blk_mq_run_hw_queues(struct request_queue *q, bool async)
2281 : {
2282 : struct blk_mq_hw_ctx *hctx, *sq_hctx;
2283 : unsigned long i;
2284 :
2285 0 : sq_hctx = NULL;
2286 0 : if (blk_queue_sq_sched(q))
2287 : sq_hctx = blk_mq_get_sq_hctx(q);
2288 0 : queue_for_each_hw_ctx(q, hctx, i) {
2289 0 : if (blk_mq_hctx_stopped(hctx))
2290 0 : continue;
2291 : /*
2292 : * Dispatch from this hctx either if there's no hctx preferred
2293 : * by IO scheduler or if it has requests that bypass the
2294 : * scheduler.
2295 : */
2296 0 : if (!sq_hctx || sq_hctx == hctx ||
2297 0 : !list_empty_careful(&hctx->dispatch))
2298 0 : blk_mq_run_hw_queue(hctx, async);
2299 : }
2300 0 : }
2301 : EXPORT_SYMBOL(blk_mq_run_hw_queues);
2302 :
2303 : /**
2304 : * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously.
2305 : * @q: Pointer to the request queue to run.
2306 : * @msecs: Milliseconds of delay to wait before running the queues.
2307 : */
2308 0 : void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs)
2309 : {
2310 : struct blk_mq_hw_ctx *hctx, *sq_hctx;
2311 : unsigned long i;
2312 :
2313 0 : sq_hctx = NULL;
2314 0 : if (blk_queue_sq_sched(q))
2315 : sq_hctx = blk_mq_get_sq_hctx(q);
2316 0 : queue_for_each_hw_ctx(q, hctx, i) {
2317 0 : if (blk_mq_hctx_stopped(hctx))
2318 0 : continue;
2319 : /*
2320 : * If there is already a run_work pending, leave the
2321 : * pending delay untouched. Otherwise, a hctx can stall
2322 : * if another hctx is re-delaying the other's work
2323 : * before the work executes.
2324 : */
2325 0 : if (delayed_work_pending(&hctx->run_work))
2326 0 : continue;
2327 : /*
2328 : * Dispatch from this hctx either if there's no hctx preferred
2329 : * by IO scheduler or if it has requests that bypass the
2330 : * scheduler.
2331 : */
2332 0 : if (!sq_hctx || sq_hctx == hctx ||
2333 0 : !list_empty_careful(&hctx->dispatch))
2334 0 : blk_mq_delay_run_hw_queue(hctx, msecs);
2335 : }
2336 0 : }
2337 : EXPORT_SYMBOL(blk_mq_delay_run_hw_queues);
2338 :
2339 : /*
2340 : * This function is often used for pausing .queue_rq() by driver when
2341 : * there isn't enough resource or some conditions aren't satisfied, and
2342 : * BLK_STS_RESOURCE is usually returned.
2343 : *
2344 : * We do not guarantee that dispatch can be drained or blocked
2345 : * after blk_mq_stop_hw_queue() returns. Please use
2346 : * blk_mq_quiesce_queue() for that requirement.
2347 : */
2348 0 : void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
2349 : {
2350 0 : cancel_delayed_work(&hctx->run_work);
2351 :
2352 0 : set_bit(BLK_MQ_S_STOPPED, &hctx->state);
2353 0 : }
2354 : EXPORT_SYMBOL(blk_mq_stop_hw_queue);
2355 :
2356 : /*
2357 : * This function is often used for pausing .queue_rq() by driver when
2358 : * there isn't enough resource or some conditions aren't satisfied, and
2359 : * BLK_STS_RESOURCE is usually returned.
2360 : *
2361 : * We do not guarantee that dispatch can be drained or blocked
2362 : * after blk_mq_stop_hw_queues() returns. Please use
2363 : * blk_mq_quiesce_queue() for that requirement.
2364 : */
2365 0 : void blk_mq_stop_hw_queues(struct request_queue *q)
2366 : {
2367 : struct blk_mq_hw_ctx *hctx;
2368 : unsigned long i;
2369 :
2370 0 : queue_for_each_hw_ctx(q, hctx, i)
2371 0 : blk_mq_stop_hw_queue(hctx);
2372 0 : }
2373 : EXPORT_SYMBOL(blk_mq_stop_hw_queues);
2374 :
2375 0 : void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx)
2376 : {
2377 0 : clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2378 :
2379 0 : blk_mq_run_hw_queue(hctx, false);
2380 0 : }
2381 : EXPORT_SYMBOL(blk_mq_start_hw_queue);
2382 :
2383 0 : void blk_mq_start_hw_queues(struct request_queue *q)
2384 : {
2385 : struct blk_mq_hw_ctx *hctx;
2386 : unsigned long i;
2387 :
2388 0 : queue_for_each_hw_ctx(q, hctx, i)
2389 0 : blk_mq_start_hw_queue(hctx);
2390 0 : }
2391 : EXPORT_SYMBOL(blk_mq_start_hw_queues);
2392 :
2393 0 : void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
2394 : {
2395 0 : if (!blk_mq_hctx_stopped(hctx))
2396 : return;
2397 :
2398 0 : clear_bit(BLK_MQ_S_STOPPED, &hctx->state);
2399 0 : blk_mq_run_hw_queue(hctx, async);
2400 : }
2401 : EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue);
2402 :
2403 0 : void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async)
2404 : {
2405 : struct blk_mq_hw_ctx *hctx;
2406 : unsigned long i;
2407 :
2408 0 : queue_for_each_hw_ctx(q, hctx, i)
2409 0 : blk_mq_start_stopped_hw_queue(hctx, async);
2410 0 : }
2411 : EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues);
2412 :
2413 0 : static void blk_mq_run_work_fn(struct work_struct *work)
2414 : {
2415 0 : struct blk_mq_hw_ctx *hctx =
2416 0 : container_of(work, struct blk_mq_hw_ctx, run_work.work);
2417 :
2418 0 : blk_mq_run_dispatch_ops(hctx->queue,
2419 : blk_mq_sched_dispatch_requests(hctx));
2420 0 : }
2421 :
2422 : /**
2423 : * blk_mq_request_bypass_insert - Insert a request at dispatch list.
2424 : * @rq: Pointer to request to be inserted.
2425 : * @flags: BLK_MQ_INSERT_*
2426 : *
2427 : * Should only be used carefully, when the caller knows we want to
2428 : * bypass a potential IO scheduler on the target device.
2429 : */
2430 0 : void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags)
2431 : {
2432 0 : struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2433 :
2434 0 : spin_lock(&hctx->lock);
2435 0 : if (flags & BLK_MQ_INSERT_AT_HEAD)
2436 0 : list_add(&rq->queuelist, &hctx->dispatch);
2437 : else
2438 0 : list_add_tail(&rq->queuelist, &hctx->dispatch);
2439 0 : spin_unlock(&hctx->lock);
2440 0 : }
2441 :
2442 0 : static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx,
2443 : struct blk_mq_ctx *ctx, struct list_head *list,
2444 : bool run_queue_async)
2445 : {
2446 : struct request *rq;
2447 0 : enum hctx_type type = hctx->type;
2448 :
2449 : /*
2450 : * Try to issue requests directly if the hw queue isn't busy to save an
2451 : * extra enqueue & dequeue to the sw queue.
2452 : */
2453 0 : if (!hctx->dispatch_busy && !run_queue_async) {
2454 0 : blk_mq_run_dispatch_ops(hctx->queue,
2455 : blk_mq_try_issue_list_directly(hctx, list));
2456 0 : if (list_empty(list))
2457 : goto out;
2458 : }
2459 :
2460 : /*
2461 : * preemption doesn't flush plug list, so it's possible ctx->cpu is
2462 : * offline now
2463 : */
2464 0 : list_for_each_entry(rq, list, queuelist) {
2465 0 : BUG_ON(rq->mq_ctx != ctx);
2466 0 : trace_block_rq_insert(rq);
2467 : }
2468 :
2469 0 : spin_lock(&ctx->lock);
2470 0 : list_splice_tail_init(list, &ctx->rq_lists[type]);
2471 0 : blk_mq_hctx_mark_pending(hctx, ctx);
2472 0 : spin_unlock(&ctx->lock);
2473 : out:
2474 0 : blk_mq_run_hw_queue(hctx, run_queue_async);
2475 0 : }
2476 :
2477 0 : static void blk_mq_insert_request(struct request *rq, blk_insert_t flags)
2478 : {
2479 0 : struct request_queue *q = rq->q;
2480 0 : struct blk_mq_ctx *ctx = rq->mq_ctx;
2481 0 : struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2482 :
2483 0 : if (blk_rq_is_passthrough(rq)) {
2484 : /*
2485 : * Passthrough request have to be added to hctx->dispatch
2486 : * directly. The device may be in a situation where it can't
2487 : * handle FS request, and always returns BLK_STS_RESOURCE for
2488 : * them, which gets them added to hctx->dispatch.
2489 : *
2490 : * If a passthrough request is required to unblock the queues,
2491 : * and it is added to the scheduler queue, there is no chance to
2492 : * dispatch it given we prioritize requests in hctx->dispatch.
2493 : */
2494 : blk_mq_request_bypass_insert(rq, flags);
2495 0 : } else if (rq->rq_flags & RQF_FLUSH_SEQ) {
2496 : /*
2497 : * Firstly normal IO request is inserted to scheduler queue or
2498 : * sw queue, meantime we add flush request to dispatch queue(
2499 : * hctx->dispatch) directly and there is at most one in-flight
2500 : * flush request for each hw queue, so it doesn't matter to add
2501 : * flush request to tail or front of the dispatch queue.
2502 : *
2503 : * Secondly in case of NCQ, flush request belongs to non-NCQ
2504 : * command, and queueing it will fail when there is any
2505 : * in-flight normal IO request(NCQ command). When adding flush
2506 : * rq to the front of hctx->dispatch, it is easier to introduce
2507 : * extra time to flush rq's latency because of S_SCHED_RESTART
2508 : * compared with adding to the tail of dispatch queue, then
2509 : * chance of flush merge is increased, and less flush requests
2510 : * will be issued to controller. It is observed that ~10% time
2511 : * is saved in blktests block/004 on disk attached to AHCI/NCQ
2512 : * drive when adding flush rq to the front of hctx->dispatch.
2513 : *
2514 : * Simply queue flush rq to the front of hctx->dispatch so that
2515 : * intensive flush workloads can benefit in case of NCQ HW.
2516 : */
2517 : blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD);
2518 0 : } else if (q->elevator) {
2519 0 : LIST_HEAD(list);
2520 :
2521 0 : WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG);
2522 :
2523 0 : list_add(&rq->queuelist, &list);
2524 0 : q->elevator->type->ops.insert_requests(hctx, &list, flags);
2525 : } else {
2526 0 : trace_block_rq_insert(rq);
2527 :
2528 0 : spin_lock(&ctx->lock);
2529 0 : if (flags & BLK_MQ_INSERT_AT_HEAD)
2530 0 : list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]);
2531 : else
2532 0 : list_add_tail(&rq->queuelist,
2533 0 : &ctx->rq_lists[hctx->type]);
2534 0 : blk_mq_hctx_mark_pending(hctx, ctx);
2535 0 : spin_unlock(&ctx->lock);
2536 : }
2537 0 : }
2538 :
2539 0 : static void blk_mq_bio_to_request(struct request *rq, struct bio *bio,
2540 : unsigned int nr_segs)
2541 : {
2542 : int err;
2543 :
2544 0 : if (bio->bi_opf & REQ_RAHEAD)
2545 0 : rq->cmd_flags |= REQ_FAILFAST_MASK;
2546 :
2547 0 : rq->__sector = bio->bi_iter.bi_sector;
2548 0 : blk_rq_bio_prep(rq, bio, nr_segs);
2549 :
2550 : /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */
2551 0 : err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO);
2552 0 : WARN_ON_ONCE(err);
2553 :
2554 0 : blk_account_io_start(rq);
2555 0 : }
2556 :
2557 0 : static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
2558 : struct request *rq, bool last)
2559 : {
2560 0 : struct request_queue *q = rq->q;
2561 0 : struct blk_mq_queue_data bd = {
2562 : .rq = rq,
2563 : .last = last,
2564 : };
2565 : blk_status_t ret;
2566 :
2567 : /*
2568 : * For OK queue, we are done. For error, caller may kill it.
2569 : * Any other error (busy), just add it to our list as we
2570 : * previously would have done.
2571 : */
2572 0 : ret = q->mq_ops->queue_rq(hctx, &bd);
2573 0 : switch (ret) {
2574 : case BLK_STS_OK:
2575 : blk_mq_update_dispatch_busy(hctx, false);
2576 : break;
2577 : case BLK_STS_RESOURCE:
2578 : case BLK_STS_DEV_RESOURCE:
2579 0 : blk_mq_update_dispatch_busy(hctx, true);
2580 0 : __blk_mq_requeue_request(rq);
2581 0 : break;
2582 : default:
2583 : blk_mq_update_dispatch_busy(hctx, false);
2584 : break;
2585 : }
2586 :
2587 0 : return ret;
2588 : }
2589 :
2590 0 : static bool blk_mq_get_budget_and_tag(struct request *rq)
2591 : {
2592 : int budget_token;
2593 :
2594 0 : budget_token = blk_mq_get_dispatch_budget(rq->q);
2595 0 : if (budget_token < 0)
2596 : return false;
2597 0 : blk_mq_set_rq_budget_token(rq, budget_token);
2598 0 : if (!blk_mq_get_driver_tag(rq)) {
2599 0 : blk_mq_put_dispatch_budget(rq->q, budget_token);
2600 : return false;
2601 : }
2602 : return true;
2603 : }
2604 :
2605 : /**
2606 : * blk_mq_try_issue_directly - Try to send a request directly to device driver.
2607 : * @hctx: Pointer of the associated hardware queue.
2608 : * @rq: Pointer to request to be sent.
2609 : *
2610 : * If the device has enough resources to accept a new request now, send the
2611 : * request directly to device driver. Else, insert at hctx->dispatch queue, so
2612 : * we can try send it another time in the future. Requests inserted at this
2613 : * queue have higher priority.
2614 : */
2615 0 : static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
2616 : struct request *rq)
2617 : {
2618 : blk_status_t ret;
2619 :
2620 0 : if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2621 0 : blk_mq_insert_request(rq, 0);
2622 0 : return;
2623 : }
2624 :
2625 0 : if ((rq->rq_flags & RQF_ELV) || !blk_mq_get_budget_and_tag(rq)) {
2626 0 : blk_mq_insert_request(rq, 0);
2627 0 : blk_mq_run_hw_queue(hctx, false);
2628 0 : return;
2629 : }
2630 :
2631 0 : ret = __blk_mq_issue_directly(hctx, rq, true);
2632 0 : switch (ret) {
2633 : case BLK_STS_OK:
2634 : break;
2635 : case BLK_STS_RESOURCE:
2636 : case BLK_STS_DEV_RESOURCE:
2637 0 : blk_mq_request_bypass_insert(rq, 0);
2638 0 : blk_mq_run_hw_queue(hctx, false);
2639 0 : break;
2640 : default:
2641 0 : blk_mq_end_request(rq, ret);
2642 0 : break;
2643 : }
2644 : }
2645 :
2646 0 : static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
2647 : {
2648 0 : struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
2649 :
2650 0 : if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) {
2651 0 : blk_mq_insert_request(rq, 0);
2652 0 : return BLK_STS_OK;
2653 : }
2654 :
2655 0 : if (!blk_mq_get_budget_and_tag(rq))
2656 : return BLK_STS_RESOURCE;
2657 0 : return __blk_mq_issue_directly(hctx, rq, last);
2658 : }
2659 :
2660 0 : static void blk_mq_plug_issue_direct(struct blk_plug *plug)
2661 : {
2662 0 : struct blk_mq_hw_ctx *hctx = NULL;
2663 : struct request *rq;
2664 0 : int queued = 0;
2665 0 : blk_status_t ret = BLK_STS_OK;
2666 :
2667 0 : while ((rq = rq_list_pop(&plug->mq_list))) {
2668 0 : bool last = rq_list_empty(plug->mq_list);
2669 :
2670 0 : if (hctx != rq->mq_hctx) {
2671 0 : if (hctx) {
2672 : blk_mq_commit_rqs(hctx, queued, false);
2673 : queued = 0;
2674 : }
2675 0 : hctx = rq->mq_hctx;
2676 : }
2677 :
2678 0 : ret = blk_mq_request_issue_directly(rq, last);
2679 0 : switch (ret) {
2680 : case BLK_STS_OK:
2681 0 : queued++;
2682 0 : break;
2683 : case BLK_STS_RESOURCE:
2684 : case BLK_STS_DEV_RESOURCE:
2685 0 : blk_mq_request_bypass_insert(rq, 0);
2686 0 : blk_mq_run_hw_queue(hctx, false);
2687 0 : goto out;
2688 : default:
2689 0 : blk_mq_end_request(rq, ret);
2690 0 : break;
2691 : }
2692 : }
2693 :
2694 : out:
2695 0 : if (ret != BLK_STS_OK)
2696 : blk_mq_commit_rqs(hctx, queued, false);
2697 0 : }
2698 :
2699 0 : static void __blk_mq_flush_plug_list(struct request_queue *q,
2700 : struct blk_plug *plug)
2701 : {
2702 0 : if (blk_queue_quiesced(q))
2703 : return;
2704 0 : q->mq_ops->queue_rqs(&plug->mq_list);
2705 : }
2706 :
2707 0 : static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched)
2708 : {
2709 0 : struct blk_mq_hw_ctx *this_hctx = NULL;
2710 0 : struct blk_mq_ctx *this_ctx = NULL;
2711 0 : struct request *requeue_list = NULL;
2712 0 : struct request **requeue_lastp = &requeue_list;
2713 0 : unsigned int depth = 0;
2714 0 : LIST_HEAD(list);
2715 :
2716 : do {
2717 0 : struct request *rq = rq_list_pop(&plug->mq_list);
2718 :
2719 0 : if (!this_hctx) {
2720 0 : this_hctx = rq->mq_hctx;
2721 0 : this_ctx = rq->mq_ctx;
2722 0 : } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx) {
2723 0 : rq_list_add_tail(&requeue_lastp, rq);
2724 0 : continue;
2725 : }
2726 0 : list_add(&rq->queuelist, &list);
2727 0 : depth++;
2728 0 : } while (!rq_list_empty(plug->mq_list));
2729 :
2730 0 : plug->mq_list = requeue_list;
2731 0 : trace_block_unplug(this_hctx->queue, depth, !from_sched);
2732 :
2733 0 : percpu_ref_get(&this_hctx->queue->q_usage_counter);
2734 0 : if (this_hctx->queue->elevator) {
2735 0 : this_hctx->queue->elevator->type->ops.insert_requests(this_hctx,
2736 : &list, 0);
2737 0 : blk_mq_run_hw_queue(this_hctx, from_sched);
2738 : } else {
2739 0 : blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched);
2740 : }
2741 0 : percpu_ref_put(&this_hctx->queue->q_usage_counter);
2742 0 : }
2743 :
2744 0 : void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
2745 : {
2746 : struct request *rq;
2747 :
2748 0 : if (rq_list_empty(plug->mq_list))
2749 : return;
2750 0 : plug->rq_count = 0;
2751 :
2752 0 : if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) {
2753 : struct request_queue *q;
2754 :
2755 0 : rq = rq_list_peek(&plug->mq_list);
2756 0 : q = rq->q;
2757 :
2758 : /*
2759 : * Peek first request and see if we have a ->queue_rqs() hook.
2760 : * If we do, we can dispatch the whole plug list in one go. We
2761 : * already know at this point that all requests belong to the
2762 : * same queue, caller must ensure that's the case.
2763 : *
2764 : * Since we pass off the full list to the driver at this point,
2765 : * we do not increment the active request count for the queue.
2766 : * Bypass shared tags for now because of that.
2767 : */
2768 0 : if (q->mq_ops->queue_rqs &&
2769 0 : !(rq->mq_hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
2770 0 : blk_mq_run_dispatch_ops(q,
2771 : __blk_mq_flush_plug_list(q, plug));
2772 0 : if (rq_list_empty(plug->mq_list))
2773 : return;
2774 : }
2775 :
2776 0 : blk_mq_run_dispatch_ops(q,
2777 : blk_mq_plug_issue_direct(plug));
2778 0 : if (rq_list_empty(plug->mq_list))
2779 : return;
2780 : }
2781 :
2782 : do {
2783 0 : blk_mq_dispatch_plug_list(plug, from_schedule);
2784 0 : } while (!rq_list_empty(plug->mq_list));
2785 : }
2786 :
2787 0 : static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
2788 : struct list_head *list)
2789 : {
2790 0 : int queued = 0;
2791 0 : blk_status_t ret = BLK_STS_OK;
2792 :
2793 0 : while (!list_empty(list)) {
2794 0 : struct request *rq = list_first_entry(list, struct request,
2795 : queuelist);
2796 :
2797 0 : list_del_init(&rq->queuelist);
2798 0 : ret = blk_mq_request_issue_directly(rq, list_empty(list));
2799 0 : switch (ret) {
2800 : case BLK_STS_OK:
2801 0 : queued++;
2802 0 : break;
2803 : case BLK_STS_RESOURCE:
2804 : case BLK_STS_DEV_RESOURCE:
2805 0 : blk_mq_request_bypass_insert(rq, 0);
2806 0 : if (list_empty(list))
2807 0 : blk_mq_run_hw_queue(hctx, false);
2808 : goto out;
2809 : default:
2810 0 : blk_mq_end_request(rq, ret);
2811 0 : break;
2812 : }
2813 : }
2814 :
2815 : out:
2816 0 : if (ret != BLK_STS_OK)
2817 : blk_mq_commit_rqs(hctx, queued, false);
2818 0 : }
2819 :
2820 0 : static bool blk_mq_attempt_bio_merge(struct request_queue *q,
2821 : struct bio *bio, unsigned int nr_segs)
2822 : {
2823 0 : if (!blk_queue_nomerges(q) && bio_mergeable(bio)) {
2824 0 : if (blk_attempt_plug_merge(q, bio, nr_segs))
2825 : return true;
2826 0 : if (blk_mq_sched_bio_merge(q, bio, nr_segs))
2827 : return true;
2828 : }
2829 : return false;
2830 : }
2831 :
2832 0 : static struct request *blk_mq_get_new_requests(struct request_queue *q,
2833 : struct blk_plug *plug,
2834 : struct bio *bio,
2835 : unsigned int nsegs)
2836 : {
2837 0 : struct blk_mq_alloc_data data = {
2838 : .q = q,
2839 : .nr_tags = 1,
2840 0 : .cmd_flags = bio->bi_opf,
2841 : };
2842 : struct request *rq;
2843 :
2844 0 : if (unlikely(bio_queue_enter(bio)))
2845 : return NULL;
2846 :
2847 0 : if (blk_mq_attempt_bio_merge(q, bio, nsegs))
2848 : goto queue_exit;
2849 :
2850 0 : rq_qos_throttle(q, bio);
2851 :
2852 0 : if (plug) {
2853 0 : data.nr_tags = plug->nr_ios;
2854 0 : plug->nr_ios = 1;
2855 0 : data.cached_rq = &plug->cached_rq;
2856 : }
2857 :
2858 0 : rq = __blk_mq_alloc_requests(&data);
2859 0 : if (rq)
2860 : return rq;
2861 0 : rq_qos_cleanup(q, bio);
2862 0 : if (bio->bi_opf & REQ_NOWAIT)
2863 : bio_wouldblock_error(bio);
2864 : queue_exit:
2865 0 : blk_queue_exit(q);
2866 0 : return NULL;
2867 : }
2868 :
2869 0 : static inline struct request *blk_mq_get_cached_request(struct request_queue *q,
2870 : struct blk_plug *plug, struct bio **bio, unsigned int nsegs)
2871 : {
2872 : struct request *rq;
2873 : enum hctx_type type, hctx_type;
2874 :
2875 0 : if (!plug)
2876 : return NULL;
2877 0 : rq = rq_list_peek(&plug->cached_rq);
2878 0 : if (!rq || rq->q != q)
2879 : return NULL;
2880 :
2881 0 : if (blk_mq_attempt_bio_merge(q, *bio, nsegs)) {
2882 0 : *bio = NULL;
2883 0 : return NULL;
2884 : }
2885 :
2886 0 : type = blk_mq_get_hctx_type((*bio)->bi_opf);
2887 0 : hctx_type = rq->mq_hctx->type;
2888 0 : if (type != hctx_type &&
2889 0 : !(type == HCTX_TYPE_READ && hctx_type == HCTX_TYPE_DEFAULT))
2890 : return NULL;
2891 0 : if (op_is_flush(rq->cmd_flags) != op_is_flush((*bio)->bi_opf))
2892 : return NULL;
2893 :
2894 : /*
2895 : * If any qos ->throttle() end up blocking, we will have flushed the
2896 : * plug and hence killed the cached_rq list as well. Pop this entry
2897 : * before we throttle.
2898 : */
2899 0 : plug->cached_rq = rq_list_next(rq);
2900 0 : rq_qos_throttle(q, *bio);
2901 :
2902 0 : rq->cmd_flags = (*bio)->bi_opf;
2903 0 : INIT_LIST_HEAD(&rq->queuelist);
2904 0 : return rq;
2905 : }
2906 :
2907 : static void bio_set_ioprio(struct bio *bio)
2908 : {
2909 : /* Nobody set ioprio so far? Initialize it based on task's nice value */
2910 0 : if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE)
2911 0 : bio->bi_ioprio = get_current_ioprio();
2912 0 : blkcg_set_ioprio(bio);
2913 : }
2914 :
2915 : /**
2916 : * blk_mq_submit_bio - Create and send a request to block device.
2917 : * @bio: Bio pointer.
2918 : *
2919 : * Builds up a request structure from @q and @bio and send to the device. The
2920 : * request may not be queued directly to hardware if:
2921 : * * This request can be merged with another one
2922 : * * We want to place request at plug queue for possible future merging
2923 : * * There is an IO scheduler active at this queue
2924 : *
2925 : * It will not queue the request if there is an error with the bio, or at the
2926 : * request creation.
2927 : */
2928 0 : void blk_mq_submit_bio(struct bio *bio)
2929 : {
2930 0 : struct request_queue *q = bdev_get_queue(bio->bi_bdev);
2931 0 : struct blk_plug *plug = blk_mq_plug(bio);
2932 0 : const int is_sync = op_is_sync(bio->bi_opf);
2933 : struct blk_mq_hw_ctx *hctx;
2934 : struct request *rq;
2935 0 : unsigned int nr_segs = 1;
2936 : blk_status_t ret;
2937 :
2938 0 : bio = blk_queue_bounce(bio, q);
2939 0 : if (bio_may_exceed_limits(bio, &q->limits)) {
2940 0 : bio = __bio_split_to_limits(bio, &q->limits, &nr_segs);
2941 0 : if (!bio)
2942 0 : return;
2943 : }
2944 :
2945 0 : if (!bio_integrity_prep(bio))
2946 : return;
2947 :
2948 0 : bio_set_ioprio(bio);
2949 :
2950 0 : rq = blk_mq_get_cached_request(q, plug, &bio, nr_segs);
2951 0 : if (!rq) {
2952 0 : if (!bio)
2953 : return;
2954 0 : rq = blk_mq_get_new_requests(q, plug, bio, nr_segs);
2955 0 : if (unlikely(!rq))
2956 : return;
2957 : }
2958 :
2959 0 : trace_block_getrq(bio);
2960 :
2961 0 : rq_qos_track(q, rq, bio);
2962 :
2963 0 : blk_mq_bio_to_request(rq, bio, nr_segs);
2964 :
2965 0 : ret = blk_crypto_rq_get_keyslot(rq);
2966 : if (ret != BLK_STS_OK) {
2967 : bio->bi_status = ret;
2968 : bio_endio(bio);
2969 : blk_mq_free_request(rq);
2970 : return;
2971 : }
2972 :
2973 0 : if (op_is_flush(bio->bi_opf)) {
2974 0 : blk_insert_flush(rq);
2975 0 : return;
2976 : }
2977 :
2978 0 : if (plug) {
2979 0 : blk_add_rq_to_plug(plug, rq);
2980 0 : return;
2981 : }
2982 :
2983 0 : hctx = rq->mq_hctx;
2984 0 : if ((rq->rq_flags & RQF_ELV) ||
2985 0 : (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) {
2986 0 : blk_mq_insert_request(rq, 0);
2987 0 : blk_mq_run_hw_queue(hctx, true);
2988 : } else {
2989 0 : blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq));
2990 : }
2991 : }
2992 :
2993 : #ifdef CONFIG_BLK_MQ_STACKING
2994 : /**
2995 : * blk_insert_cloned_request - Helper for stacking drivers to submit a request
2996 : * @rq: the request being queued
2997 : */
2998 : blk_status_t blk_insert_cloned_request(struct request *rq)
2999 : {
3000 : struct request_queue *q = rq->q;
3001 : unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq));
3002 : unsigned int max_segments = blk_rq_get_max_segments(rq);
3003 : blk_status_t ret;
3004 :
3005 : if (blk_rq_sectors(rq) > max_sectors) {
3006 : /*
3007 : * SCSI device does not have a good way to return if
3008 : * Write Same/Zero is actually supported. If a device rejects
3009 : * a non-read/write command (discard, write same,etc.) the
3010 : * low-level device driver will set the relevant queue limit to
3011 : * 0 to prevent blk-lib from issuing more of the offending
3012 : * operations. Commands queued prior to the queue limit being
3013 : * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O
3014 : * errors being propagated to upper layers.
3015 : */
3016 : if (max_sectors == 0)
3017 : return BLK_STS_NOTSUPP;
3018 :
3019 : printk(KERN_ERR "%s: over max size limit. (%u > %u)\n",
3020 : __func__, blk_rq_sectors(rq), max_sectors);
3021 : return BLK_STS_IOERR;
3022 : }
3023 :
3024 : /*
3025 : * The queue settings related to segment counting may differ from the
3026 : * original queue.
3027 : */
3028 : rq->nr_phys_segments = blk_recalc_rq_segments(rq);
3029 : if (rq->nr_phys_segments > max_segments) {
3030 : printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n",
3031 : __func__, rq->nr_phys_segments, max_segments);
3032 : return BLK_STS_IOERR;
3033 : }
3034 :
3035 : if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq)))
3036 : return BLK_STS_IOERR;
3037 :
3038 : ret = blk_crypto_rq_get_keyslot(rq);
3039 : if (ret != BLK_STS_OK)
3040 : return ret;
3041 :
3042 : blk_account_io_start(rq);
3043 :
3044 : /*
3045 : * Since we have a scheduler attached on the top device,
3046 : * bypass a potential scheduler on the bottom device for
3047 : * insert.
3048 : */
3049 : blk_mq_run_dispatch_ops(q,
3050 : ret = blk_mq_request_issue_directly(rq, true));
3051 : if (ret)
3052 : blk_account_io_done(rq, ktime_get_ns());
3053 : return ret;
3054 : }
3055 : EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
3056 :
3057 : /**
3058 : * blk_rq_unprep_clone - Helper function to free all bios in a cloned request
3059 : * @rq: the clone request to be cleaned up
3060 : *
3061 : * Description:
3062 : * Free all bios in @rq for a cloned request.
3063 : */
3064 : void blk_rq_unprep_clone(struct request *rq)
3065 : {
3066 : struct bio *bio;
3067 :
3068 : while ((bio = rq->bio) != NULL) {
3069 : rq->bio = bio->bi_next;
3070 :
3071 : bio_put(bio);
3072 : }
3073 : }
3074 : EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
3075 :
3076 : /**
3077 : * blk_rq_prep_clone - Helper function to setup clone request
3078 : * @rq: the request to be setup
3079 : * @rq_src: original request to be cloned
3080 : * @bs: bio_set that bios for clone are allocated from
3081 : * @gfp_mask: memory allocation mask for bio
3082 : * @bio_ctr: setup function to be called for each clone bio.
3083 : * Returns %0 for success, non %0 for failure.
3084 : * @data: private data to be passed to @bio_ctr
3085 : *
3086 : * Description:
3087 : * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
3088 : * Also, pages which the original bios are pointing to are not copied
3089 : * and the cloned bios just point same pages.
3090 : * So cloned bios must be completed before original bios, which means
3091 : * the caller must complete @rq before @rq_src.
3092 : */
3093 : int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
3094 : struct bio_set *bs, gfp_t gfp_mask,
3095 : int (*bio_ctr)(struct bio *, struct bio *, void *),
3096 : void *data)
3097 : {
3098 : struct bio *bio, *bio_src;
3099 :
3100 : if (!bs)
3101 : bs = &fs_bio_set;
3102 :
3103 : __rq_for_each_bio(bio_src, rq_src) {
3104 : bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask,
3105 : bs);
3106 : if (!bio)
3107 : goto free_and_out;
3108 :
3109 : if (bio_ctr && bio_ctr(bio, bio_src, data))
3110 : goto free_and_out;
3111 :
3112 : if (rq->bio) {
3113 : rq->biotail->bi_next = bio;
3114 : rq->biotail = bio;
3115 : } else {
3116 : rq->bio = rq->biotail = bio;
3117 : }
3118 : bio = NULL;
3119 : }
3120 :
3121 : /* Copy attributes of the original request to the clone request. */
3122 : rq->__sector = blk_rq_pos(rq_src);
3123 : rq->__data_len = blk_rq_bytes(rq_src);
3124 : if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) {
3125 : rq->rq_flags |= RQF_SPECIAL_PAYLOAD;
3126 : rq->special_vec = rq_src->special_vec;
3127 : }
3128 : rq->nr_phys_segments = rq_src->nr_phys_segments;
3129 : rq->ioprio = rq_src->ioprio;
3130 :
3131 : if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0)
3132 : goto free_and_out;
3133 :
3134 : return 0;
3135 :
3136 : free_and_out:
3137 : if (bio)
3138 : bio_put(bio);
3139 : blk_rq_unprep_clone(rq);
3140 :
3141 : return -ENOMEM;
3142 : }
3143 : EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
3144 : #endif /* CONFIG_BLK_MQ_STACKING */
3145 :
3146 : /*
3147 : * Steal bios from a request and add them to a bio list.
3148 : * The request must not have been partially completed before.
3149 : */
3150 0 : void blk_steal_bios(struct bio_list *list, struct request *rq)
3151 : {
3152 0 : if (rq->bio) {
3153 0 : if (list->tail)
3154 0 : list->tail->bi_next = rq->bio;
3155 : else
3156 0 : list->head = rq->bio;
3157 0 : list->tail = rq->biotail;
3158 :
3159 0 : rq->bio = NULL;
3160 0 : rq->biotail = NULL;
3161 : }
3162 :
3163 0 : rq->__data_len = 0;
3164 0 : }
3165 : EXPORT_SYMBOL_GPL(blk_steal_bios);
3166 :
3167 : static size_t order_to_size(unsigned int order)
3168 : {
3169 0 : return (size_t)PAGE_SIZE << order;
3170 : }
3171 :
3172 : /* called before freeing request pool in @tags */
3173 0 : static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags,
3174 : struct blk_mq_tags *tags)
3175 : {
3176 : struct page *page;
3177 : unsigned long flags;
3178 :
3179 : /*
3180 : * There is no need to clear mapping if driver tags is not initialized
3181 : * or the mapping belongs to the driver tags.
3182 : */
3183 0 : if (!drv_tags || drv_tags == tags)
3184 : return;
3185 :
3186 0 : list_for_each_entry(page, &tags->page_list, lru) {
3187 0 : unsigned long start = (unsigned long)page_address(page);
3188 0 : unsigned long end = start + order_to_size(page->private);
3189 : int i;
3190 :
3191 0 : for (i = 0; i < drv_tags->nr_tags; i++) {
3192 0 : struct request *rq = drv_tags->rqs[i];
3193 0 : unsigned long rq_addr = (unsigned long)rq;
3194 :
3195 0 : if (rq_addr >= start && rq_addr < end) {
3196 0 : WARN_ON_ONCE(req_ref_read(rq) != 0);
3197 0 : cmpxchg(&drv_tags->rqs[i], rq, NULL);
3198 : }
3199 : }
3200 : }
3201 :
3202 : /*
3203 : * Wait until all pending iteration is done.
3204 : *
3205 : * Request reference is cleared and it is guaranteed to be observed
3206 : * after the ->lock is released.
3207 : */
3208 0 : spin_lock_irqsave(&drv_tags->lock, flags);
3209 0 : spin_unlock_irqrestore(&drv_tags->lock, flags);
3210 : }
3211 :
3212 0 : void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
3213 : unsigned int hctx_idx)
3214 : {
3215 : struct blk_mq_tags *drv_tags;
3216 : struct page *page;
3217 :
3218 0 : if (list_empty(&tags->page_list))
3219 : return;
3220 :
3221 0 : if (blk_mq_is_shared_tags(set->flags))
3222 0 : drv_tags = set->shared_tags;
3223 : else
3224 0 : drv_tags = set->tags[hctx_idx];
3225 :
3226 0 : if (tags->static_rqs && set->ops->exit_request) {
3227 : int i;
3228 :
3229 0 : for (i = 0; i < tags->nr_tags; i++) {
3230 0 : struct request *rq = tags->static_rqs[i];
3231 :
3232 0 : if (!rq)
3233 0 : continue;
3234 0 : set->ops->exit_request(set, rq, hctx_idx);
3235 0 : tags->static_rqs[i] = NULL;
3236 : }
3237 : }
3238 :
3239 0 : blk_mq_clear_rq_mapping(drv_tags, tags);
3240 :
3241 0 : while (!list_empty(&tags->page_list)) {
3242 0 : page = list_first_entry(&tags->page_list, struct page, lru);
3243 0 : list_del_init(&page->lru);
3244 : /*
3245 : * Remove kmemleak object previously allocated in
3246 : * blk_mq_alloc_rqs().
3247 : */
3248 0 : kmemleak_free(page_address(page));
3249 0 : __free_pages(page, page->private);
3250 : }
3251 : }
3252 :
3253 0 : void blk_mq_free_rq_map(struct blk_mq_tags *tags)
3254 : {
3255 0 : kfree(tags->rqs);
3256 0 : tags->rqs = NULL;
3257 0 : kfree(tags->static_rqs);
3258 0 : tags->static_rqs = NULL;
3259 :
3260 0 : blk_mq_free_tags(tags);
3261 0 : }
3262 :
3263 : static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set,
3264 : unsigned int hctx_idx)
3265 : {
3266 : int i;
3267 :
3268 0 : for (i = 0; i < set->nr_maps; i++) {
3269 0 : unsigned int start = set->map[i].queue_offset;
3270 0 : unsigned int end = start + set->map[i].nr_queues;
3271 :
3272 0 : if (hctx_idx >= start && hctx_idx < end)
3273 : break;
3274 : }
3275 :
3276 0 : if (i >= set->nr_maps)
3277 0 : i = HCTX_TYPE_DEFAULT;
3278 :
3279 0 : return i;
3280 : }
3281 :
3282 0 : static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set,
3283 : unsigned int hctx_idx)
3284 : {
3285 0 : enum hctx_type type = hctx_idx_to_type(set, hctx_idx);
3286 :
3287 0 : return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx);
3288 : }
3289 :
3290 0 : static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
3291 : unsigned int hctx_idx,
3292 : unsigned int nr_tags,
3293 : unsigned int reserved_tags)
3294 : {
3295 0 : int node = blk_mq_get_hctx_node(set, hctx_idx);
3296 : struct blk_mq_tags *tags;
3297 :
3298 0 : if (node == NUMA_NO_NODE)
3299 0 : node = set->numa_node;
3300 :
3301 0 : tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
3302 0 : BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
3303 0 : if (!tags)
3304 : return NULL;
3305 :
3306 0 : tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3307 : GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3308 : node);
3309 0 : if (!tags->rqs)
3310 : goto err_free_tags;
3311 :
3312 0 : tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *),
3313 : GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
3314 : node);
3315 0 : if (!tags->static_rqs)
3316 : goto err_free_rqs;
3317 :
3318 : return tags;
3319 :
3320 : err_free_rqs:
3321 0 : kfree(tags->rqs);
3322 : err_free_tags:
3323 0 : blk_mq_free_tags(tags);
3324 0 : return NULL;
3325 : }
3326 :
3327 : static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
3328 : unsigned int hctx_idx, int node)
3329 : {
3330 : int ret;
3331 :
3332 0 : if (set->ops->init_request) {
3333 0 : ret = set->ops->init_request(set, rq, hctx_idx, node);
3334 0 : if (ret)
3335 : return ret;
3336 : }
3337 :
3338 0 : WRITE_ONCE(rq->state, MQ_RQ_IDLE);
3339 : return 0;
3340 : }
3341 :
3342 0 : static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set,
3343 : struct blk_mq_tags *tags,
3344 : unsigned int hctx_idx, unsigned int depth)
3345 : {
3346 0 : unsigned int i, j, entries_per_page, max_order = 4;
3347 0 : int node = blk_mq_get_hctx_node(set, hctx_idx);
3348 : size_t rq_size, left;
3349 :
3350 0 : if (node == NUMA_NO_NODE)
3351 0 : node = set->numa_node;
3352 :
3353 0 : INIT_LIST_HEAD(&tags->page_list);
3354 :
3355 : /*
3356 : * rq_size is the size of the request plus driver payload, rounded
3357 : * to the cacheline size
3358 : */
3359 0 : rq_size = round_up(sizeof(struct request) + set->cmd_size,
3360 : cache_line_size());
3361 0 : left = rq_size * depth;
3362 :
3363 0 : for (i = 0; i < depth; ) {
3364 : int this_order = max_order;
3365 : struct page *page;
3366 : int to_do;
3367 : void *p;
3368 :
3369 0 : while (this_order && left < order_to_size(this_order - 1))
3370 : this_order--;
3371 :
3372 : do {
3373 0 : page = alloc_pages_node(node,
3374 : GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
3375 : this_order);
3376 0 : if (page)
3377 : break;
3378 0 : if (!this_order--)
3379 : break;
3380 0 : if (order_to_size(this_order) < rq_size)
3381 : break;
3382 : } while (1);
3383 :
3384 0 : if (!page)
3385 : goto fail;
3386 :
3387 0 : page->private = this_order;
3388 0 : list_add_tail(&page->lru, &tags->page_list);
3389 :
3390 0 : p = page_address(page);
3391 : /*
3392 : * Allow kmemleak to scan these pages as they contain pointers
3393 : * to additional allocations like via ops->init_request().
3394 : */
3395 0 : kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
3396 0 : entries_per_page = order_to_size(this_order) / rq_size;
3397 0 : to_do = min(entries_per_page, depth - i);
3398 0 : left -= to_do * rq_size;
3399 0 : for (j = 0; j < to_do; j++) {
3400 0 : struct request *rq = p;
3401 :
3402 0 : tags->static_rqs[i] = rq;
3403 0 : if (blk_mq_init_request(set, rq, hctx_idx, node)) {
3404 0 : tags->static_rqs[i] = NULL;
3405 0 : goto fail;
3406 : }
3407 :
3408 0 : p += rq_size;
3409 0 : i++;
3410 : }
3411 : }
3412 : return 0;
3413 :
3414 : fail:
3415 0 : blk_mq_free_rqs(set, tags, hctx_idx);
3416 0 : return -ENOMEM;
3417 : }
3418 :
3419 : struct rq_iter_data {
3420 : struct blk_mq_hw_ctx *hctx;
3421 : bool has_rq;
3422 : };
3423 :
3424 0 : static bool blk_mq_has_request(struct request *rq, void *data)
3425 : {
3426 0 : struct rq_iter_data *iter_data = data;
3427 :
3428 0 : if (rq->mq_hctx != iter_data->hctx)
3429 : return true;
3430 0 : iter_data->has_rq = true;
3431 0 : return false;
3432 : }
3433 :
3434 0 : static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx)
3435 : {
3436 0 : struct blk_mq_tags *tags = hctx->sched_tags ?
3437 0 : hctx->sched_tags : hctx->tags;
3438 0 : struct rq_iter_data data = {
3439 : .hctx = hctx,
3440 : };
3441 :
3442 0 : blk_mq_all_tag_iter(tags, blk_mq_has_request, &data);
3443 0 : return data.has_rq;
3444 : }
3445 :
3446 0 : static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu,
3447 : struct blk_mq_hw_ctx *hctx)
3448 : {
3449 0 : if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu)
3450 : return false;
3451 0 : if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids)
3452 : return false;
3453 0 : return true;
3454 : }
3455 :
3456 0 : static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node)
3457 : {
3458 0 : struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3459 : struct blk_mq_hw_ctx, cpuhp_online);
3460 :
3461 0 : if (!cpumask_test_cpu(cpu, hctx->cpumask) ||
3462 0 : !blk_mq_last_cpu_in_hctx(cpu, hctx))
3463 : return 0;
3464 :
3465 : /*
3466 : * Prevent new request from being allocated on the current hctx.
3467 : *
3468 : * The smp_mb__after_atomic() Pairs with the implied barrier in
3469 : * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is
3470 : * seen once we return from the tag allocator.
3471 : */
3472 0 : set_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3473 0 : smp_mb__after_atomic();
3474 :
3475 : /*
3476 : * Try to grab a reference to the queue and wait for any outstanding
3477 : * requests. If we could not grab a reference the queue has been
3478 : * frozen and there are no requests.
3479 : */
3480 0 : if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) {
3481 0 : while (blk_mq_hctx_has_requests(hctx))
3482 0 : msleep(5);
3483 0 : percpu_ref_put(&hctx->queue->q_usage_counter);
3484 : }
3485 :
3486 : return 0;
3487 : }
3488 :
3489 0 : static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node)
3490 : {
3491 0 : struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node,
3492 : struct blk_mq_hw_ctx, cpuhp_online);
3493 :
3494 0 : if (cpumask_test_cpu(cpu, hctx->cpumask))
3495 0 : clear_bit(BLK_MQ_S_INACTIVE, &hctx->state);
3496 0 : return 0;
3497 : }
3498 :
3499 : /*
3500 : * 'cpu' is going away. splice any existing rq_list entries from this
3501 : * software queue to the hw queue dispatch list, and ensure that it
3502 : * gets run.
3503 : */
3504 0 : static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
3505 : {
3506 : struct blk_mq_hw_ctx *hctx;
3507 : struct blk_mq_ctx *ctx;
3508 0 : LIST_HEAD(tmp);
3509 : enum hctx_type type;
3510 :
3511 0 : hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
3512 0 : if (!cpumask_test_cpu(cpu, hctx->cpumask))
3513 : return 0;
3514 :
3515 0 : ctx = __blk_mq_get_ctx(hctx->queue, cpu);
3516 0 : type = hctx->type;
3517 :
3518 0 : spin_lock(&ctx->lock);
3519 0 : if (!list_empty(&ctx->rq_lists[type])) {
3520 0 : list_splice_init(&ctx->rq_lists[type], &tmp);
3521 : blk_mq_hctx_clear_pending(hctx, ctx);
3522 : }
3523 0 : spin_unlock(&ctx->lock);
3524 :
3525 0 : if (list_empty(&tmp))
3526 : return 0;
3527 :
3528 0 : spin_lock(&hctx->lock);
3529 0 : list_splice_tail_init(&tmp, &hctx->dispatch);
3530 0 : spin_unlock(&hctx->lock);
3531 :
3532 0 : blk_mq_run_hw_queue(hctx, true);
3533 0 : return 0;
3534 : }
3535 :
3536 0 : static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
3537 : {
3538 0 : if (!(hctx->flags & BLK_MQ_F_STACKING))
3539 0 : cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3540 : &hctx->cpuhp_online);
3541 0 : cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
3542 : &hctx->cpuhp_dead);
3543 0 : }
3544 :
3545 : /*
3546 : * Before freeing hw queue, clearing the flush request reference in
3547 : * tags->rqs[] for avoiding potential UAF.
3548 : */
3549 0 : static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags,
3550 : unsigned int queue_depth, struct request *flush_rq)
3551 : {
3552 : int i;
3553 : unsigned long flags;
3554 :
3555 : /* The hw queue may not be mapped yet */
3556 0 : if (!tags)
3557 : return;
3558 :
3559 0 : WARN_ON_ONCE(req_ref_read(flush_rq) != 0);
3560 :
3561 0 : for (i = 0; i < queue_depth; i++)
3562 0 : cmpxchg(&tags->rqs[i], flush_rq, NULL);
3563 :
3564 : /*
3565 : * Wait until all pending iteration is done.
3566 : *
3567 : * Request reference is cleared and it is guaranteed to be observed
3568 : * after the ->lock is released.
3569 : */
3570 0 : spin_lock_irqsave(&tags->lock, flags);
3571 0 : spin_unlock_irqrestore(&tags->lock, flags);
3572 : }
3573 :
3574 : /* hctx->ctxs will be freed in queue's release handler */
3575 0 : static void blk_mq_exit_hctx(struct request_queue *q,
3576 : struct blk_mq_tag_set *set,
3577 : struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
3578 : {
3579 0 : struct request *flush_rq = hctx->fq->flush_rq;
3580 :
3581 0 : if (blk_mq_hw_queue_mapped(hctx))
3582 : blk_mq_tag_idle(hctx);
3583 :
3584 0 : if (blk_queue_init_done(q))
3585 0 : blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx],
3586 : set->queue_depth, flush_rq);
3587 0 : if (set->ops->exit_request)
3588 0 : set->ops->exit_request(set, flush_rq, hctx_idx);
3589 :
3590 0 : if (set->ops->exit_hctx)
3591 0 : set->ops->exit_hctx(hctx, hctx_idx);
3592 :
3593 0 : blk_mq_remove_cpuhp(hctx);
3594 :
3595 0 : xa_erase(&q->hctx_table, hctx_idx);
3596 :
3597 0 : spin_lock(&q->unused_hctx_lock);
3598 0 : list_add(&hctx->hctx_list, &q->unused_hctx_list);
3599 0 : spin_unlock(&q->unused_hctx_lock);
3600 0 : }
3601 :
3602 0 : static void blk_mq_exit_hw_queues(struct request_queue *q,
3603 : struct blk_mq_tag_set *set, int nr_queue)
3604 : {
3605 : struct blk_mq_hw_ctx *hctx;
3606 : unsigned long i;
3607 :
3608 0 : queue_for_each_hw_ctx(q, hctx, i) {
3609 0 : if (i == nr_queue)
3610 : break;
3611 0 : blk_mq_exit_hctx(q, set, hctx, i);
3612 : }
3613 0 : }
3614 :
3615 0 : static int blk_mq_init_hctx(struct request_queue *q,
3616 : struct blk_mq_tag_set *set,
3617 : struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
3618 : {
3619 0 : hctx->queue_num = hctx_idx;
3620 :
3621 0 : if (!(hctx->flags & BLK_MQ_F_STACKING))
3622 0 : cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE,
3623 : &hctx->cpuhp_online);
3624 0 : cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
3625 :
3626 0 : hctx->tags = set->tags[hctx_idx];
3627 :
3628 0 : if (set->ops->init_hctx &&
3629 0 : set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
3630 : goto unregister_cpu_notifier;
3631 :
3632 0 : if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx,
3633 0 : hctx->numa_node))
3634 : goto exit_hctx;
3635 :
3636 0 : if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL))
3637 : goto exit_flush_rq;
3638 :
3639 : return 0;
3640 :
3641 : exit_flush_rq:
3642 0 : if (set->ops->exit_request)
3643 0 : set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx);
3644 : exit_hctx:
3645 0 : if (set->ops->exit_hctx)
3646 0 : set->ops->exit_hctx(hctx, hctx_idx);
3647 : unregister_cpu_notifier:
3648 0 : blk_mq_remove_cpuhp(hctx);
3649 0 : return -1;
3650 : }
3651 :
3652 : static struct blk_mq_hw_ctx *
3653 0 : blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set,
3654 : int node)
3655 : {
3656 : struct blk_mq_hw_ctx *hctx;
3657 0 : gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
3658 :
3659 0 : hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node);
3660 0 : if (!hctx)
3661 : goto fail_alloc_hctx;
3662 :
3663 0 : if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node))
3664 : goto free_hctx;
3665 :
3666 0 : atomic_set(&hctx->nr_active, 0);
3667 0 : if (node == NUMA_NO_NODE)
3668 0 : node = set->numa_node;
3669 0 : hctx->numa_node = node;
3670 :
3671 0 : INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn);
3672 0 : spin_lock_init(&hctx->lock);
3673 0 : INIT_LIST_HEAD(&hctx->dispatch);
3674 0 : hctx->queue = q;
3675 0 : hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED;
3676 :
3677 0 : INIT_LIST_HEAD(&hctx->hctx_list);
3678 :
3679 : /*
3680 : * Allocate space for all possible cpus to avoid allocation at
3681 : * runtime
3682 : */
3683 0 : hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *),
3684 : gfp, node);
3685 0 : if (!hctx->ctxs)
3686 : goto free_cpumask;
3687 :
3688 0 : if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8),
3689 : gfp, node, false, false))
3690 : goto free_ctxs;
3691 0 : hctx->nr_ctx = 0;
3692 :
3693 0 : spin_lock_init(&hctx->dispatch_wait_lock);
3694 0 : init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
3695 0 : INIT_LIST_HEAD(&hctx->dispatch_wait.entry);
3696 :
3697 0 : hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp);
3698 0 : if (!hctx->fq)
3699 : goto free_bitmap;
3700 :
3701 0 : blk_mq_hctx_kobj_init(hctx);
3702 :
3703 0 : return hctx;
3704 :
3705 : free_bitmap:
3706 0 : sbitmap_free(&hctx->ctx_map);
3707 : free_ctxs:
3708 0 : kfree(hctx->ctxs);
3709 : free_cpumask:
3710 0 : free_cpumask_var(hctx->cpumask);
3711 : free_hctx:
3712 0 : kfree(hctx);
3713 : fail_alloc_hctx:
3714 : return NULL;
3715 : }
3716 :
3717 0 : static void blk_mq_init_cpu_queues(struct request_queue *q,
3718 : unsigned int nr_hw_queues)
3719 : {
3720 0 : struct blk_mq_tag_set *set = q->tag_set;
3721 : unsigned int i, j;
3722 :
3723 0 : for_each_possible_cpu(i) {
3724 0 : struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
3725 : struct blk_mq_hw_ctx *hctx;
3726 : int k;
3727 :
3728 0 : __ctx->cpu = i;
3729 0 : spin_lock_init(&__ctx->lock);
3730 0 : for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++)
3731 0 : INIT_LIST_HEAD(&__ctx->rq_lists[k]);
3732 :
3733 0 : __ctx->queue = q;
3734 :
3735 : /*
3736 : * Set local node, IFF we have more than one hw queue. If
3737 : * not, we remain on the home node of the device
3738 : */
3739 0 : for (j = 0; j < set->nr_maps; j++) {
3740 0 : hctx = blk_mq_map_queue_type(q, j, i);
3741 0 : if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
3742 0 : hctx->numa_node = cpu_to_node(i);
3743 : }
3744 : }
3745 0 : }
3746 :
3747 0 : struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3748 : unsigned int hctx_idx,
3749 : unsigned int depth)
3750 : {
3751 : struct blk_mq_tags *tags;
3752 : int ret;
3753 :
3754 0 : tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags);
3755 0 : if (!tags)
3756 : return NULL;
3757 :
3758 0 : ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth);
3759 0 : if (ret) {
3760 0 : blk_mq_free_rq_map(tags);
3761 0 : return NULL;
3762 : }
3763 :
3764 : return tags;
3765 : }
3766 :
3767 0 : static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set,
3768 : int hctx_idx)
3769 : {
3770 0 : if (blk_mq_is_shared_tags(set->flags)) {
3771 0 : set->tags[hctx_idx] = set->shared_tags;
3772 :
3773 0 : return true;
3774 : }
3775 :
3776 0 : set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx,
3777 : set->queue_depth);
3778 :
3779 0 : return set->tags[hctx_idx];
3780 : }
3781 :
3782 0 : void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3783 : struct blk_mq_tags *tags,
3784 : unsigned int hctx_idx)
3785 : {
3786 0 : if (tags) {
3787 0 : blk_mq_free_rqs(set, tags, hctx_idx);
3788 0 : blk_mq_free_rq_map(tags);
3789 : }
3790 0 : }
3791 :
3792 0 : static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set,
3793 : unsigned int hctx_idx)
3794 : {
3795 0 : if (!blk_mq_is_shared_tags(set->flags))
3796 0 : blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx);
3797 :
3798 0 : set->tags[hctx_idx] = NULL;
3799 0 : }
3800 :
3801 0 : static void blk_mq_map_swqueue(struct request_queue *q)
3802 : {
3803 : unsigned int j, hctx_idx;
3804 : unsigned long i;
3805 : struct blk_mq_hw_ctx *hctx;
3806 : struct blk_mq_ctx *ctx;
3807 0 : struct blk_mq_tag_set *set = q->tag_set;
3808 :
3809 0 : queue_for_each_hw_ctx(q, hctx, i) {
3810 0 : cpumask_clear(hctx->cpumask);
3811 0 : hctx->nr_ctx = 0;
3812 0 : hctx->dispatch_from = NULL;
3813 : }
3814 :
3815 : /*
3816 : * Map software to hardware queues.
3817 : *
3818 : * If the cpu isn't present, the cpu is mapped to first hctx.
3819 : */
3820 0 : for_each_possible_cpu(i) {
3821 :
3822 0 : ctx = per_cpu_ptr(q->queue_ctx, i);
3823 0 : for (j = 0; j < set->nr_maps; j++) {
3824 0 : if (!set->map[j].nr_queues) {
3825 0 : ctx->hctxs[j] = blk_mq_map_queue_type(q,
3826 : HCTX_TYPE_DEFAULT, i);
3827 0 : continue;
3828 : }
3829 0 : hctx_idx = set->map[j].mq_map[i];
3830 : /* unmapped hw queue can be remapped after CPU topo changed */
3831 0 : if (!set->tags[hctx_idx] &&
3832 0 : !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) {
3833 : /*
3834 : * If tags initialization fail for some hctx,
3835 : * that hctx won't be brought online. In this
3836 : * case, remap the current ctx to hctx[0] which
3837 : * is guaranteed to always have tags allocated
3838 : */
3839 0 : set->map[j].mq_map[i] = 0;
3840 : }
3841 :
3842 0 : hctx = blk_mq_map_queue_type(q, j, i);
3843 0 : ctx->hctxs[j] = hctx;
3844 : /*
3845 : * If the CPU is already set in the mask, then we've
3846 : * mapped this one already. This can happen if
3847 : * devices share queues across queue maps.
3848 : */
3849 0 : if (cpumask_test_cpu(i, hctx->cpumask))
3850 0 : continue;
3851 :
3852 0 : cpumask_set_cpu(i, hctx->cpumask);
3853 0 : hctx->type = j;
3854 0 : ctx->index_hw[hctx->type] = hctx->nr_ctx;
3855 0 : hctx->ctxs[hctx->nr_ctx++] = ctx;
3856 :
3857 : /*
3858 : * If the nr_ctx type overflows, we have exceeded the
3859 : * amount of sw queues we can support.
3860 : */
3861 0 : BUG_ON(!hctx->nr_ctx);
3862 : }
3863 :
3864 0 : for (; j < HCTX_MAX_TYPES; j++)
3865 0 : ctx->hctxs[j] = blk_mq_map_queue_type(q,
3866 : HCTX_TYPE_DEFAULT, i);
3867 : }
3868 :
3869 0 : queue_for_each_hw_ctx(q, hctx, i) {
3870 : /*
3871 : * If no software queues are mapped to this hardware queue,
3872 : * disable it and free the request entries.
3873 : */
3874 0 : if (!hctx->nr_ctx) {
3875 : /* Never unmap queue 0. We need it as a
3876 : * fallback in case of a new remap fails
3877 : * allocation
3878 : */
3879 0 : if (i)
3880 0 : __blk_mq_free_map_and_rqs(set, i);
3881 :
3882 0 : hctx->tags = NULL;
3883 0 : continue;
3884 : }
3885 :
3886 0 : hctx->tags = set->tags[i];
3887 0 : WARN_ON(!hctx->tags);
3888 :
3889 : /*
3890 : * Set the map size to the number of mapped software queues.
3891 : * This is more accurate and more efficient than looping
3892 : * over all possibly mapped software queues.
3893 : */
3894 0 : sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
3895 :
3896 : /*
3897 : * Initialize batch roundrobin counts
3898 : */
3899 0 : hctx->next_cpu = blk_mq_first_mapped_cpu(hctx);
3900 0 : hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
3901 : }
3902 0 : }
3903 :
3904 : /*
3905 : * Caller needs to ensure that we're either frozen/quiesced, or that
3906 : * the queue isn't live yet.
3907 : */
3908 0 : static void queue_set_hctx_shared(struct request_queue *q, bool shared)
3909 : {
3910 : struct blk_mq_hw_ctx *hctx;
3911 : unsigned long i;
3912 :
3913 0 : queue_for_each_hw_ctx(q, hctx, i) {
3914 0 : if (shared) {
3915 0 : hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3916 : } else {
3917 0 : blk_mq_tag_idle(hctx);
3918 0 : hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3919 : }
3920 : }
3921 0 : }
3922 :
3923 0 : static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set,
3924 : bool shared)
3925 : {
3926 : struct request_queue *q;
3927 :
3928 : lockdep_assert_held(&set->tag_list_lock);
3929 :
3930 0 : list_for_each_entry(q, &set->tag_list, tag_set_list) {
3931 0 : blk_mq_freeze_queue(q);
3932 0 : queue_set_hctx_shared(q, shared);
3933 0 : blk_mq_unfreeze_queue(q);
3934 : }
3935 0 : }
3936 :
3937 0 : static void blk_mq_del_queue_tag_set(struct request_queue *q)
3938 : {
3939 0 : struct blk_mq_tag_set *set = q->tag_set;
3940 :
3941 0 : mutex_lock(&set->tag_list_lock);
3942 0 : list_del(&q->tag_set_list);
3943 0 : if (list_is_singular(&set->tag_list)) {
3944 : /* just transitioned to unshared */
3945 0 : set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED;
3946 : /* update existing queue */
3947 0 : blk_mq_update_tag_set_shared(set, false);
3948 : }
3949 0 : mutex_unlock(&set->tag_list_lock);
3950 0 : INIT_LIST_HEAD(&q->tag_set_list);
3951 0 : }
3952 :
3953 0 : static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
3954 : struct request_queue *q)
3955 : {
3956 0 : mutex_lock(&set->tag_list_lock);
3957 :
3958 : /*
3959 : * Check to see if we're transitioning to shared (from 1 to 2 queues).
3960 : */
3961 0 : if (!list_empty(&set->tag_list) &&
3962 0 : !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) {
3963 0 : set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED;
3964 : /* update existing queue */
3965 0 : blk_mq_update_tag_set_shared(set, true);
3966 : }
3967 0 : if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)
3968 0 : queue_set_hctx_shared(q, true);
3969 0 : list_add_tail(&q->tag_set_list, &set->tag_list);
3970 :
3971 0 : mutex_unlock(&set->tag_list_lock);
3972 0 : }
3973 :
3974 : /* All allocations will be freed in release handler of q->mq_kobj */
3975 0 : static int blk_mq_alloc_ctxs(struct request_queue *q)
3976 : {
3977 : struct blk_mq_ctxs *ctxs;
3978 : int cpu;
3979 :
3980 0 : ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL);
3981 0 : if (!ctxs)
3982 : return -ENOMEM;
3983 :
3984 0 : ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx);
3985 0 : if (!ctxs->queue_ctx)
3986 : goto fail;
3987 :
3988 0 : for_each_possible_cpu(cpu) {
3989 0 : struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu);
3990 0 : ctx->ctxs = ctxs;
3991 : }
3992 :
3993 0 : q->mq_kobj = &ctxs->kobj;
3994 0 : q->queue_ctx = ctxs->queue_ctx;
3995 :
3996 : return 0;
3997 : fail:
3998 0 : kfree(ctxs);
3999 : return -ENOMEM;
4000 : }
4001 :
4002 : /*
4003 : * It is the actual release handler for mq, but we do it from
4004 : * request queue's release handler for avoiding use-after-free
4005 : * and headache because q->mq_kobj shouldn't have been introduced,
4006 : * but we can't group ctx/kctx kobj without it.
4007 : */
4008 0 : void blk_mq_release(struct request_queue *q)
4009 : {
4010 : struct blk_mq_hw_ctx *hctx, *next;
4011 : unsigned long i;
4012 :
4013 0 : queue_for_each_hw_ctx(q, hctx, i)
4014 0 : WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list));
4015 :
4016 : /* all hctx are in .unused_hctx_list now */
4017 0 : list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) {
4018 0 : list_del_init(&hctx->hctx_list);
4019 0 : kobject_put(&hctx->kobj);
4020 : }
4021 :
4022 0 : xa_destroy(&q->hctx_table);
4023 :
4024 : /*
4025 : * release .mq_kobj and sw queue's kobject now because
4026 : * both share lifetime with request queue.
4027 : */
4028 0 : blk_mq_sysfs_deinit(q);
4029 0 : }
4030 :
4031 0 : static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set,
4032 : void *queuedata)
4033 : {
4034 : struct request_queue *q;
4035 : int ret;
4036 :
4037 0 : q = blk_alloc_queue(set->numa_node);
4038 0 : if (!q)
4039 : return ERR_PTR(-ENOMEM);
4040 0 : q->queuedata = queuedata;
4041 0 : ret = blk_mq_init_allocated_queue(set, q);
4042 0 : if (ret) {
4043 0 : blk_put_queue(q);
4044 0 : return ERR_PTR(ret);
4045 : }
4046 : return q;
4047 : }
4048 :
4049 0 : struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
4050 : {
4051 0 : return blk_mq_init_queue_data(set, NULL);
4052 : }
4053 : EXPORT_SYMBOL(blk_mq_init_queue);
4054 :
4055 : /**
4056 : * blk_mq_destroy_queue - shutdown a request queue
4057 : * @q: request queue to shutdown
4058 : *
4059 : * This shuts down a request queue allocated by blk_mq_init_queue(). All future
4060 : * requests will be failed with -ENODEV. The caller is responsible for dropping
4061 : * the reference from blk_mq_init_queue() by calling blk_put_queue().
4062 : *
4063 : * Context: can sleep
4064 : */
4065 0 : void blk_mq_destroy_queue(struct request_queue *q)
4066 : {
4067 0 : WARN_ON_ONCE(!queue_is_mq(q));
4068 0 : WARN_ON_ONCE(blk_queue_registered(q));
4069 :
4070 : might_sleep();
4071 :
4072 0 : blk_queue_flag_set(QUEUE_FLAG_DYING, q);
4073 0 : blk_queue_start_drain(q);
4074 0 : blk_mq_freeze_queue_wait(q);
4075 :
4076 0 : blk_sync_queue(q);
4077 0 : blk_mq_cancel_work_sync(q);
4078 0 : blk_mq_exit_queue(q);
4079 0 : }
4080 : EXPORT_SYMBOL(blk_mq_destroy_queue);
4081 :
4082 0 : struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata,
4083 : struct lock_class_key *lkclass)
4084 : {
4085 : struct request_queue *q;
4086 : struct gendisk *disk;
4087 :
4088 0 : q = blk_mq_init_queue_data(set, queuedata);
4089 0 : if (IS_ERR(q))
4090 : return ERR_CAST(q);
4091 :
4092 0 : disk = __alloc_disk_node(q, set->numa_node, lkclass);
4093 0 : if (!disk) {
4094 0 : blk_mq_destroy_queue(q);
4095 0 : blk_put_queue(q);
4096 0 : return ERR_PTR(-ENOMEM);
4097 : }
4098 0 : set_bit(GD_OWNS_QUEUE, &disk->state);
4099 0 : return disk;
4100 : }
4101 : EXPORT_SYMBOL(__blk_mq_alloc_disk);
4102 :
4103 0 : struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q,
4104 : struct lock_class_key *lkclass)
4105 : {
4106 : struct gendisk *disk;
4107 :
4108 0 : if (!blk_get_queue(q))
4109 : return NULL;
4110 0 : disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass);
4111 0 : if (!disk)
4112 0 : blk_put_queue(q);
4113 : return disk;
4114 : }
4115 : EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue);
4116 :
4117 0 : static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx(
4118 : struct blk_mq_tag_set *set, struct request_queue *q,
4119 : int hctx_idx, int node)
4120 : {
4121 0 : struct blk_mq_hw_ctx *hctx = NULL, *tmp;
4122 :
4123 : /* reuse dead hctx first */
4124 0 : spin_lock(&q->unused_hctx_lock);
4125 0 : list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) {
4126 0 : if (tmp->numa_node == node) {
4127 : hctx = tmp;
4128 : break;
4129 : }
4130 : }
4131 0 : if (hctx)
4132 0 : list_del_init(&hctx->hctx_list);
4133 0 : spin_unlock(&q->unused_hctx_lock);
4134 :
4135 0 : if (!hctx)
4136 0 : hctx = blk_mq_alloc_hctx(q, set, node);
4137 0 : if (!hctx)
4138 : goto fail;
4139 :
4140 0 : if (blk_mq_init_hctx(q, set, hctx, hctx_idx))
4141 : goto free_hctx;
4142 :
4143 : return hctx;
4144 :
4145 : free_hctx:
4146 0 : kobject_put(&hctx->kobj);
4147 : fail:
4148 : return NULL;
4149 : }
4150 :
4151 0 : static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
4152 : struct request_queue *q)
4153 : {
4154 : struct blk_mq_hw_ctx *hctx;
4155 : unsigned long i, j;
4156 :
4157 : /* protect against switching io scheduler */
4158 0 : mutex_lock(&q->sysfs_lock);
4159 0 : for (i = 0; i < set->nr_hw_queues; i++) {
4160 : int old_node;
4161 0 : int node = blk_mq_get_hctx_node(set, i);
4162 0 : struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i);
4163 :
4164 0 : if (old_hctx) {
4165 0 : old_node = old_hctx->numa_node;
4166 0 : blk_mq_exit_hctx(q, set, old_hctx, i);
4167 : }
4168 :
4169 0 : if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) {
4170 0 : if (!old_hctx)
4171 : break;
4172 0 : pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n",
4173 : node, old_node);
4174 0 : hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node);
4175 0 : WARN_ON_ONCE(!hctx);
4176 : }
4177 : }
4178 : /*
4179 : * Increasing nr_hw_queues fails. Free the newly allocated
4180 : * hctxs and keep the previous q->nr_hw_queues.
4181 : */
4182 0 : if (i != set->nr_hw_queues) {
4183 0 : j = q->nr_hw_queues;
4184 : } else {
4185 0 : j = i;
4186 0 : q->nr_hw_queues = set->nr_hw_queues;
4187 : }
4188 :
4189 0 : xa_for_each_start(&q->hctx_table, j, hctx, j)
4190 0 : blk_mq_exit_hctx(q, set, hctx, j);
4191 0 : mutex_unlock(&q->sysfs_lock);
4192 0 : }
4193 :
4194 0 : static void blk_mq_update_poll_flag(struct request_queue *q)
4195 : {
4196 0 : struct blk_mq_tag_set *set = q->tag_set;
4197 :
4198 0 : if (set->nr_maps > HCTX_TYPE_POLL &&
4199 0 : set->map[HCTX_TYPE_POLL].nr_queues)
4200 0 : blk_queue_flag_set(QUEUE_FLAG_POLL, q);
4201 : else
4202 0 : blk_queue_flag_clear(QUEUE_FLAG_POLL, q);
4203 0 : }
4204 :
4205 0 : int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
4206 : struct request_queue *q)
4207 : {
4208 : /* mark the queue as mq asap */
4209 0 : q->mq_ops = set->ops;
4210 :
4211 0 : if (blk_mq_alloc_ctxs(q))
4212 : goto err_exit;
4213 :
4214 : /* init q->mq_kobj and sw queues' kobjects */
4215 0 : blk_mq_sysfs_init(q);
4216 :
4217 0 : INIT_LIST_HEAD(&q->unused_hctx_list);
4218 0 : spin_lock_init(&q->unused_hctx_lock);
4219 :
4220 0 : xa_init(&q->hctx_table);
4221 :
4222 0 : blk_mq_realloc_hw_ctxs(set, q);
4223 0 : if (!q->nr_hw_queues)
4224 : goto err_hctxs;
4225 :
4226 0 : INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
4227 0 : blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
4228 :
4229 0 : q->tag_set = set;
4230 :
4231 0 : q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
4232 0 : blk_mq_update_poll_flag(q);
4233 :
4234 0 : INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
4235 0 : INIT_LIST_HEAD(&q->requeue_list);
4236 0 : spin_lock_init(&q->requeue_lock);
4237 :
4238 0 : q->nr_requests = set->queue_depth;
4239 :
4240 0 : blk_mq_init_cpu_queues(q, set->nr_hw_queues);
4241 0 : blk_mq_add_queue_tag_set(set, q);
4242 0 : blk_mq_map_swqueue(q);
4243 0 : return 0;
4244 :
4245 : err_hctxs:
4246 0 : blk_mq_release(q);
4247 : err_exit:
4248 0 : q->mq_ops = NULL;
4249 0 : return -ENOMEM;
4250 : }
4251 : EXPORT_SYMBOL(blk_mq_init_allocated_queue);
4252 :
4253 : /* tags can _not_ be used after returning from blk_mq_exit_queue */
4254 0 : void blk_mq_exit_queue(struct request_queue *q)
4255 : {
4256 0 : struct blk_mq_tag_set *set = q->tag_set;
4257 :
4258 : /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */
4259 0 : blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
4260 : /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */
4261 0 : blk_mq_del_queue_tag_set(q);
4262 0 : }
4263 :
4264 0 : static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
4265 : {
4266 : int i;
4267 :
4268 0 : if (blk_mq_is_shared_tags(set->flags)) {
4269 0 : set->shared_tags = blk_mq_alloc_map_and_rqs(set,
4270 : BLK_MQ_NO_HCTX_IDX,
4271 : set->queue_depth);
4272 0 : if (!set->shared_tags)
4273 : return -ENOMEM;
4274 : }
4275 :
4276 0 : for (i = 0; i < set->nr_hw_queues; i++) {
4277 0 : if (!__blk_mq_alloc_map_and_rqs(set, i))
4278 : goto out_unwind;
4279 0 : cond_resched();
4280 : }
4281 :
4282 : return 0;
4283 :
4284 : out_unwind:
4285 0 : while (--i >= 0)
4286 0 : __blk_mq_free_map_and_rqs(set, i);
4287 :
4288 0 : if (blk_mq_is_shared_tags(set->flags)) {
4289 0 : blk_mq_free_map_and_rqs(set, set->shared_tags,
4290 : BLK_MQ_NO_HCTX_IDX);
4291 : }
4292 :
4293 : return -ENOMEM;
4294 : }
4295 :
4296 : /*
4297 : * Allocate the request maps associated with this tag_set. Note that this
4298 : * may reduce the depth asked for, if memory is tight. set->queue_depth
4299 : * will be updated to reflect the allocated depth.
4300 : */
4301 0 : static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set)
4302 : {
4303 : unsigned int depth;
4304 : int err;
4305 :
4306 0 : depth = set->queue_depth;
4307 : do {
4308 0 : err = __blk_mq_alloc_rq_maps(set);
4309 0 : if (!err)
4310 : break;
4311 :
4312 0 : set->queue_depth >>= 1;
4313 0 : if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
4314 : err = -ENOMEM;
4315 : break;
4316 : }
4317 0 : } while (set->queue_depth);
4318 :
4319 0 : if (!set->queue_depth || err) {
4320 0 : pr_err("blk-mq: failed to allocate request map\n");
4321 0 : return -ENOMEM;
4322 : }
4323 :
4324 0 : if (depth != set->queue_depth)
4325 0 : pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
4326 : depth, set->queue_depth);
4327 :
4328 : return 0;
4329 : }
4330 :
4331 0 : static void blk_mq_update_queue_map(struct blk_mq_tag_set *set)
4332 : {
4333 : /*
4334 : * blk_mq_map_queues() and multiple .map_queues() implementations
4335 : * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the
4336 : * number of hardware queues.
4337 : */
4338 0 : if (set->nr_maps == 1)
4339 0 : set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues;
4340 :
4341 0 : if (set->ops->map_queues && !is_kdump_kernel()) {
4342 : int i;
4343 :
4344 : /*
4345 : * transport .map_queues is usually done in the following
4346 : * way:
4347 : *
4348 : * for (queue = 0; queue < set->nr_hw_queues; queue++) {
4349 : * mask = get_cpu_mask(queue)
4350 : * for_each_cpu(cpu, mask)
4351 : * set->map[x].mq_map[cpu] = queue;
4352 : * }
4353 : *
4354 : * When we need to remap, the table has to be cleared for
4355 : * killing stale mapping since one CPU may not be mapped
4356 : * to any hw queue.
4357 : */
4358 0 : for (i = 0; i < set->nr_maps; i++)
4359 0 : blk_mq_clear_mq_map(&set->map[i]);
4360 :
4361 0 : set->ops->map_queues(set);
4362 : } else {
4363 0 : BUG_ON(set->nr_maps > 1);
4364 0 : blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
4365 : }
4366 0 : }
4367 :
4368 0 : static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set,
4369 : int new_nr_hw_queues)
4370 : {
4371 : struct blk_mq_tags **new_tags;
4372 :
4373 0 : if (set->nr_hw_queues >= new_nr_hw_queues)
4374 : goto done;
4375 :
4376 0 : new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *),
4377 : GFP_KERNEL, set->numa_node);
4378 0 : if (!new_tags)
4379 : return -ENOMEM;
4380 :
4381 0 : if (set->tags)
4382 0 : memcpy(new_tags, set->tags, set->nr_hw_queues *
4383 : sizeof(*set->tags));
4384 0 : kfree(set->tags);
4385 0 : set->tags = new_tags;
4386 : done:
4387 0 : set->nr_hw_queues = new_nr_hw_queues;
4388 0 : return 0;
4389 : }
4390 :
4391 : /*
4392 : * Alloc a tag set to be associated with one or more request queues.
4393 : * May fail with EINVAL for various error conditions. May adjust the
4394 : * requested depth down, if it's too large. In that case, the set
4395 : * value will be stored in set->queue_depth.
4396 : */
4397 0 : int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
4398 : {
4399 : int i, ret;
4400 :
4401 : BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
4402 :
4403 0 : if (!set->nr_hw_queues)
4404 : return -EINVAL;
4405 0 : if (!set->queue_depth)
4406 : return -EINVAL;
4407 0 : if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
4408 : return -EINVAL;
4409 :
4410 0 : if (!set->ops->queue_rq)
4411 : return -EINVAL;
4412 :
4413 0 : if (!set->ops->get_budget ^ !set->ops->put_budget)
4414 : return -EINVAL;
4415 :
4416 0 : if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
4417 0 : pr_info("blk-mq: reduced tag depth to %u\n",
4418 : BLK_MQ_MAX_DEPTH);
4419 0 : set->queue_depth = BLK_MQ_MAX_DEPTH;
4420 : }
4421 :
4422 0 : if (!set->nr_maps)
4423 0 : set->nr_maps = 1;
4424 0 : else if (set->nr_maps > HCTX_MAX_TYPES)
4425 : return -EINVAL;
4426 :
4427 : /*
4428 : * If a crashdump is active, then we are potentially in a very
4429 : * memory constrained environment. Limit us to 1 queue and
4430 : * 64 tags to prevent using too much memory.
4431 : */
4432 : if (is_kdump_kernel()) {
4433 : set->nr_hw_queues = 1;
4434 : set->nr_maps = 1;
4435 : set->queue_depth = min(64U, set->queue_depth);
4436 : }
4437 : /*
4438 : * There is no use for more h/w queues than cpus if we just have
4439 : * a single map
4440 : */
4441 0 : if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids)
4442 0 : set->nr_hw_queues = nr_cpu_ids;
4443 :
4444 0 : if (set->flags & BLK_MQ_F_BLOCKING) {
4445 0 : set->srcu = kmalloc(sizeof(*set->srcu), GFP_KERNEL);
4446 0 : if (!set->srcu)
4447 : return -ENOMEM;
4448 0 : ret = init_srcu_struct(set->srcu);
4449 0 : if (ret)
4450 : goto out_free_srcu;
4451 : }
4452 :
4453 0 : ret = -ENOMEM;
4454 0 : set->tags = kcalloc_node(set->nr_hw_queues,
4455 : sizeof(struct blk_mq_tags *), GFP_KERNEL,
4456 : set->numa_node);
4457 0 : if (!set->tags)
4458 : goto out_cleanup_srcu;
4459 :
4460 0 : for (i = 0; i < set->nr_maps; i++) {
4461 0 : set->map[i].mq_map = kcalloc_node(nr_cpu_ids,
4462 : sizeof(set->map[i].mq_map[0]),
4463 : GFP_KERNEL, set->numa_node);
4464 0 : if (!set->map[i].mq_map)
4465 : goto out_free_mq_map;
4466 0 : set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues;
4467 : }
4468 :
4469 0 : blk_mq_update_queue_map(set);
4470 :
4471 0 : ret = blk_mq_alloc_set_map_and_rqs(set);
4472 0 : if (ret)
4473 : goto out_free_mq_map;
4474 :
4475 0 : mutex_init(&set->tag_list_lock);
4476 0 : INIT_LIST_HEAD(&set->tag_list);
4477 :
4478 0 : return 0;
4479 :
4480 : out_free_mq_map:
4481 0 : for (i = 0; i < set->nr_maps; i++) {
4482 0 : kfree(set->map[i].mq_map);
4483 0 : set->map[i].mq_map = NULL;
4484 : }
4485 0 : kfree(set->tags);
4486 0 : set->tags = NULL;
4487 : out_cleanup_srcu:
4488 0 : if (set->flags & BLK_MQ_F_BLOCKING)
4489 0 : cleanup_srcu_struct(set->srcu);
4490 : out_free_srcu:
4491 0 : if (set->flags & BLK_MQ_F_BLOCKING)
4492 0 : kfree(set->srcu);
4493 : return ret;
4494 : }
4495 : EXPORT_SYMBOL(blk_mq_alloc_tag_set);
4496 :
4497 : /* allocate and initialize a tagset for a simple single-queue device */
4498 0 : int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set,
4499 : const struct blk_mq_ops *ops, unsigned int queue_depth,
4500 : unsigned int set_flags)
4501 : {
4502 0 : memset(set, 0, sizeof(*set));
4503 0 : set->ops = ops;
4504 0 : set->nr_hw_queues = 1;
4505 0 : set->nr_maps = 1;
4506 0 : set->queue_depth = queue_depth;
4507 0 : set->numa_node = NUMA_NO_NODE;
4508 0 : set->flags = set_flags;
4509 0 : return blk_mq_alloc_tag_set(set);
4510 : }
4511 : EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set);
4512 :
4513 0 : void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
4514 : {
4515 : int i, j;
4516 :
4517 0 : for (i = 0; i < set->nr_hw_queues; i++)
4518 0 : __blk_mq_free_map_and_rqs(set, i);
4519 :
4520 0 : if (blk_mq_is_shared_tags(set->flags)) {
4521 0 : blk_mq_free_map_and_rqs(set, set->shared_tags,
4522 : BLK_MQ_NO_HCTX_IDX);
4523 : }
4524 :
4525 0 : for (j = 0; j < set->nr_maps; j++) {
4526 0 : kfree(set->map[j].mq_map);
4527 0 : set->map[j].mq_map = NULL;
4528 : }
4529 :
4530 0 : kfree(set->tags);
4531 0 : set->tags = NULL;
4532 0 : if (set->flags & BLK_MQ_F_BLOCKING) {
4533 0 : cleanup_srcu_struct(set->srcu);
4534 0 : kfree(set->srcu);
4535 : }
4536 0 : }
4537 : EXPORT_SYMBOL(blk_mq_free_tag_set);
4538 :
4539 0 : int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
4540 : {
4541 0 : struct blk_mq_tag_set *set = q->tag_set;
4542 : struct blk_mq_hw_ctx *hctx;
4543 : int ret;
4544 : unsigned long i;
4545 :
4546 0 : if (!set)
4547 : return -EINVAL;
4548 :
4549 0 : if (q->nr_requests == nr)
4550 : return 0;
4551 :
4552 0 : blk_mq_freeze_queue(q);
4553 0 : blk_mq_quiesce_queue(q);
4554 :
4555 0 : ret = 0;
4556 0 : queue_for_each_hw_ctx(q, hctx, i) {
4557 0 : if (!hctx->tags)
4558 0 : continue;
4559 : /*
4560 : * If we're using an MQ scheduler, just update the scheduler
4561 : * queue depth. This is similar to what the old code would do.
4562 : */
4563 0 : if (hctx->sched_tags) {
4564 0 : ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
4565 : nr, true);
4566 : } else {
4567 0 : ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr,
4568 : false);
4569 : }
4570 0 : if (ret)
4571 : break;
4572 0 : if (q->elevator && q->elevator->type->ops.depth_updated)
4573 0 : q->elevator->type->ops.depth_updated(hctx);
4574 : }
4575 0 : if (!ret) {
4576 0 : q->nr_requests = nr;
4577 0 : if (blk_mq_is_shared_tags(set->flags)) {
4578 0 : if (q->elevator)
4579 0 : blk_mq_tag_update_sched_shared_tags(q);
4580 : else
4581 0 : blk_mq_tag_resize_shared_tags(set, nr);
4582 : }
4583 : }
4584 :
4585 0 : blk_mq_unquiesce_queue(q);
4586 0 : blk_mq_unfreeze_queue(q);
4587 :
4588 0 : return ret;
4589 : }
4590 :
4591 : /*
4592 : * request_queue and elevator_type pair.
4593 : * It is just used by __blk_mq_update_nr_hw_queues to cache
4594 : * the elevator_type associated with a request_queue.
4595 : */
4596 : struct blk_mq_qe_pair {
4597 : struct list_head node;
4598 : struct request_queue *q;
4599 : struct elevator_type *type;
4600 : };
4601 :
4602 : /*
4603 : * Cache the elevator_type in qe pair list and switch the
4604 : * io scheduler to 'none'
4605 : */
4606 0 : static bool blk_mq_elv_switch_none(struct list_head *head,
4607 : struct request_queue *q)
4608 : {
4609 : struct blk_mq_qe_pair *qe;
4610 :
4611 0 : if (!q->elevator)
4612 : return true;
4613 :
4614 0 : qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY);
4615 0 : if (!qe)
4616 : return false;
4617 :
4618 : /* q->elevator needs protection from ->sysfs_lock */
4619 0 : mutex_lock(&q->sysfs_lock);
4620 :
4621 0 : INIT_LIST_HEAD(&qe->node);
4622 0 : qe->q = q;
4623 0 : qe->type = q->elevator->type;
4624 : /* keep a reference to the elevator module as we'll switch back */
4625 0 : __elevator_get(qe->type);
4626 0 : list_add(&qe->node, head);
4627 0 : elevator_disable(q);
4628 0 : mutex_unlock(&q->sysfs_lock);
4629 :
4630 0 : return true;
4631 : }
4632 :
4633 : static struct blk_mq_qe_pair *blk_lookup_qe_pair(struct list_head *head,
4634 : struct request_queue *q)
4635 : {
4636 : struct blk_mq_qe_pair *qe;
4637 :
4638 0 : list_for_each_entry(qe, head, node)
4639 0 : if (qe->q == q)
4640 : return qe;
4641 :
4642 : return NULL;
4643 : }
4644 :
4645 0 : static void blk_mq_elv_switch_back(struct list_head *head,
4646 : struct request_queue *q)
4647 : {
4648 : struct blk_mq_qe_pair *qe;
4649 : struct elevator_type *t;
4650 :
4651 0 : qe = blk_lookup_qe_pair(head, q);
4652 0 : if (!qe)
4653 : return;
4654 0 : t = qe->type;
4655 0 : list_del(&qe->node);
4656 0 : kfree(qe);
4657 :
4658 0 : mutex_lock(&q->sysfs_lock);
4659 0 : elevator_switch(q, t);
4660 : /* drop the reference acquired in blk_mq_elv_switch_none */
4661 0 : elevator_put(t);
4662 0 : mutex_unlock(&q->sysfs_lock);
4663 : }
4664 :
4665 0 : static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set,
4666 : int nr_hw_queues)
4667 : {
4668 : struct request_queue *q;
4669 0 : LIST_HEAD(head);
4670 : int prev_nr_hw_queues;
4671 :
4672 : lockdep_assert_held(&set->tag_list_lock);
4673 :
4674 0 : if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids)
4675 0 : nr_hw_queues = nr_cpu_ids;
4676 0 : if (nr_hw_queues < 1)
4677 0 : return;
4678 0 : if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues)
4679 : return;
4680 :
4681 0 : list_for_each_entry(q, &set->tag_list, tag_set_list)
4682 0 : blk_mq_freeze_queue(q);
4683 : /*
4684 : * Switch IO scheduler to 'none', cleaning up the data associated
4685 : * with the previous scheduler. We will switch back once we are done
4686 : * updating the new sw to hw queue mappings.
4687 : */
4688 0 : list_for_each_entry(q, &set->tag_list, tag_set_list)
4689 0 : if (!blk_mq_elv_switch_none(&head, q))
4690 : goto switch_back;
4691 :
4692 0 : list_for_each_entry(q, &set->tag_list, tag_set_list) {
4693 0 : blk_mq_debugfs_unregister_hctxs(q);
4694 0 : blk_mq_sysfs_unregister_hctxs(q);
4695 : }
4696 :
4697 0 : prev_nr_hw_queues = set->nr_hw_queues;
4698 0 : if (blk_mq_realloc_tag_set_tags(set, nr_hw_queues) < 0)
4699 : goto reregister;
4700 :
4701 : fallback:
4702 0 : blk_mq_update_queue_map(set);
4703 0 : list_for_each_entry(q, &set->tag_list, tag_set_list) {
4704 0 : blk_mq_realloc_hw_ctxs(set, q);
4705 0 : blk_mq_update_poll_flag(q);
4706 0 : if (q->nr_hw_queues != set->nr_hw_queues) {
4707 0 : int i = prev_nr_hw_queues;
4708 :
4709 0 : pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n",
4710 : nr_hw_queues, prev_nr_hw_queues);
4711 0 : for (; i < set->nr_hw_queues; i++)
4712 0 : __blk_mq_free_map_and_rqs(set, i);
4713 :
4714 0 : set->nr_hw_queues = prev_nr_hw_queues;
4715 0 : blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
4716 0 : goto fallback;
4717 : }
4718 0 : blk_mq_map_swqueue(q);
4719 : }
4720 :
4721 : reregister:
4722 0 : list_for_each_entry(q, &set->tag_list, tag_set_list) {
4723 0 : blk_mq_sysfs_register_hctxs(q);
4724 0 : blk_mq_debugfs_register_hctxs(q);
4725 : }
4726 :
4727 : switch_back:
4728 0 : list_for_each_entry(q, &set->tag_list, tag_set_list)
4729 0 : blk_mq_elv_switch_back(&head, q);
4730 :
4731 0 : list_for_each_entry(q, &set->tag_list, tag_set_list)
4732 0 : blk_mq_unfreeze_queue(q);
4733 : }
4734 :
4735 0 : void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
4736 : {
4737 0 : mutex_lock(&set->tag_list_lock);
4738 0 : __blk_mq_update_nr_hw_queues(set, nr_hw_queues);
4739 0 : mutex_unlock(&set->tag_list_lock);
4740 0 : }
4741 : EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
4742 :
4743 0 : int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, struct io_comp_batch *iob,
4744 : unsigned int flags)
4745 : {
4746 0 : struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, cookie);
4747 0 : long state = get_current_state();
4748 : int ret;
4749 :
4750 : do {
4751 0 : ret = q->mq_ops->poll(hctx, iob);
4752 0 : if (ret > 0) {
4753 0 : __set_current_state(TASK_RUNNING);
4754 0 : return ret;
4755 : }
4756 :
4757 0 : if (signal_pending_state(state, current))
4758 0 : __set_current_state(TASK_RUNNING);
4759 0 : if (task_is_running(current))
4760 : return 1;
4761 :
4762 0 : if (ret < 0 || (flags & BLK_POLL_ONESHOT))
4763 : break;
4764 : cpu_relax();
4765 0 : } while (!need_resched());
4766 :
4767 0 : __set_current_state(TASK_RUNNING);
4768 0 : return 0;
4769 : }
4770 :
4771 0 : unsigned int blk_mq_rq_cpu(struct request *rq)
4772 : {
4773 0 : return rq->mq_ctx->cpu;
4774 : }
4775 : EXPORT_SYMBOL(blk_mq_rq_cpu);
4776 :
4777 0 : void blk_mq_cancel_work_sync(struct request_queue *q)
4778 : {
4779 : struct blk_mq_hw_ctx *hctx;
4780 : unsigned long i;
4781 :
4782 0 : cancel_delayed_work_sync(&q->requeue_work);
4783 :
4784 0 : queue_for_each_hw_ctx(q, hctx, i)
4785 0 : cancel_delayed_work_sync(&hctx->run_work);
4786 0 : }
4787 :
4788 1 : static int __init blk_mq_init(void)
4789 : {
4790 : int i;
4791 :
4792 2 : for_each_possible_cpu(i)
4793 2 : init_llist_head(&per_cpu(blk_cpu_done, i));
4794 1 : open_softirq(BLOCK_SOFTIRQ, blk_done_softirq);
4795 :
4796 1 : cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD,
4797 : "block/softirq:dead", NULL,
4798 : blk_softirq_cpu_dead);
4799 1 : cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
4800 : blk_mq_hctx_notify_dead);
4801 1 : cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online",
4802 : blk_mq_hctx_notify_online,
4803 : blk_mq_hctx_notify_offline);
4804 1 : return 0;
4805 : }
4806 : subsys_initcall(blk_mq_init);
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