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1 | /* | |
2 | * Block multiqueue core code | |
3 | * | |
4 | * Copyright (C) 2013-2014 Jens Axboe | |
5 | * Copyright (C) 2013-2014 Christoph Hellwig | |
6 | */ | |
7 | #include <linux/kernel.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/backing-dev.h> | |
10 | #include <linux/bio.h> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/kmemleak.h> | |
13 | #include <linux/mm.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/workqueue.h> | |
17 | #include <linux/smp.h> | |
18 | #include <linux/llist.h> | |
19 | #include <linux/list_sort.h> | |
20 | #include <linux/cpu.h> | |
21 | #include <linux/cache.h> | |
22 | #include <linux/sched/sysctl.h> | |
23 | #include <linux/sched/topology.h> | |
24 | #include <linux/sched/signal.h> | |
25 | #include <linux/delay.h> | |
26 | #include <linux/crash_dump.h> | |
27 | #include <linux/prefetch.h> | |
28 | ||
29 | #include <trace/events/block.h> | |
30 | ||
31 | #include <linux/blk-mq.h> | |
32 | #include "blk.h" | |
33 | #include "blk-mq.h" | |
34 | #include "blk-mq-debugfs.h" | |
35 | #include "blk-mq-tag.h" | |
36 | #include "blk-pm.h" | |
37 | #include "blk-stat.h" | |
38 | #include "blk-mq-sched.h" | |
39 | #include "blk-rq-qos.h" | |
40 | ||
41 | static bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie); | |
42 | static void blk_mq_poll_stats_start(struct request_queue *q); | |
43 | static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb); | |
44 | ||
45 | static int blk_mq_poll_stats_bkt(const struct request *rq) | |
46 | { | |
47 | int ddir, bytes, bucket; | |
48 | ||
49 | ddir = rq_data_dir(rq); | |
50 | bytes = blk_rq_bytes(rq); | |
51 | ||
52 | bucket = ddir + 2*(ilog2(bytes) - 9); | |
53 | ||
54 | if (bucket < 0) | |
55 | return -1; | |
56 | else if (bucket >= BLK_MQ_POLL_STATS_BKTS) | |
57 | return ddir + BLK_MQ_POLL_STATS_BKTS - 2; | |
58 | ||
59 | return bucket; | |
60 | } | |
61 | ||
62 | /* | |
63 | * Check if any of the ctx's have pending work in this hardware queue | |
64 | */ | |
65 | static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) | |
66 | { | |
67 | return !list_empty_careful(&hctx->dispatch) || | |
68 | sbitmap_any_bit_set(&hctx->ctx_map) || | |
69 | blk_mq_sched_has_work(hctx); | |
70 | } | |
71 | ||
72 | /* | |
73 | * Mark this ctx as having pending work in this hardware queue | |
74 | */ | |
75 | static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx, | |
76 | struct blk_mq_ctx *ctx) | |
77 | { | |
78 | if (!sbitmap_test_bit(&hctx->ctx_map, ctx->index_hw)) | |
79 | sbitmap_set_bit(&hctx->ctx_map, ctx->index_hw); | |
80 | } | |
81 | ||
82 | static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, | |
83 | struct blk_mq_ctx *ctx) | |
84 | { | |
85 | sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw); | |
86 | } | |
87 | ||
88 | struct mq_inflight { | |
89 | struct hd_struct *part; | |
90 | unsigned int *inflight; | |
91 | }; | |
92 | ||
93 | static void blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx, | |
94 | struct request *rq, void *priv, | |
95 | bool reserved) | |
96 | { | |
97 | struct mq_inflight *mi = priv; | |
98 | ||
99 | /* | |
100 | * index[0] counts the specific partition that was asked for. index[1] | |
101 | * counts the ones that are active on the whole device, so increment | |
102 | * that if mi->part is indeed a partition, and not a whole device. | |
103 | */ | |
104 | if (rq->part == mi->part) | |
105 | mi->inflight[0]++; | |
106 | if (mi->part->partno) | |
107 | mi->inflight[1]++; | |
108 | } | |
109 | ||
110 | void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part, | |
111 | unsigned int inflight[2]) | |
112 | { | |
113 | struct mq_inflight mi = { .part = part, .inflight = inflight, }; | |
114 | ||
115 | inflight[0] = inflight[1] = 0; | |
116 | blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi); | |
117 | } | |
118 | ||
119 | static void blk_mq_check_inflight_rw(struct blk_mq_hw_ctx *hctx, | |
120 | struct request *rq, void *priv, | |
121 | bool reserved) | |
122 | { | |
123 | struct mq_inflight *mi = priv; | |
124 | ||
125 | if (rq->part == mi->part) | |
126 | mi->inflight[rq_data_dir(rq)]++; | |
127 | } | |
128 | ||
129 | void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part, | |
130 | unsigned int inflight[2]) | |
131 | { | |
132 | struct mq_inflight mi = { .part = part, .inflight = inflight, }; | |
133 | ||
134 | inflight[0] = inflight[1] = 0; | |
135 | blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight_rw, &mi); | |
136 | } | |
137 | ||
138 | void blk_freeze_queue_start(struct request_queue *q) | |
139 | { | |
140 | int freeze_depth; | |
141 | ||
142 | freeze_depth = atomic_inc_return(&q->mq_freeze_depth); | |
143 | if (freeze_depth == 1) { | |
144 | percpu_ref_kill(&q->q_usage_counter); | |
145 | if (q->mq_ops) | |
146 | blk_mq_run_hw_queues(q, false); | |
147 | } | |
148 | } | |
149 | EXPORT_SYMBOL_GPL(blk_freeze_queue_start); | |
150 | ||
151 | void blk_mq_freeze_queue_wait(struct request_queue *q) | |
152 | { | |
153 | wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter)); | |
154 | } | |
155 | EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait); | |
156 | ||
157 | int blk_mq_freeze_queue_wait_timeout(struct request_queue *q, | |
158 | unsigned long timeout) | |
159 | { | |
160 | return wait_event_timeout(q->mq_freeze_wq, | |
161 | percpu_ref_is_zero(&q->q_usage_counter), | |
162 | timeout); | |
163 | } | |
164 | EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout); | |
165 | ||
166 | /* | |
167 | * Guarantee no request is in use, so we can change any data structure of | |
168 | * the queue afterward. | |
169 | */ | |
170 | void blk_freeze_queue(struct request_queue *q) | |
171 | { | |
172 | /* | |
173 | * In the !blk_mq case we are only calling this to kill the | |
174 | * q_usage_counter, otherwise this increases the freeze depth | |
175 | * and waits for it to return to zero. For this reason there is | |
176 | * no blk_unfreeze_queue(), and blk_freeze_queue() is not | |
177 | * exported to drivers as the only user for unfreeze is blk_mq. | |
178 | */ | |
179 | blk_freeze_queue_start(q); | |
180 | if (!q->mq_ops) | |
181 | blk_drain_queue(q); | |
182 | blk_mq_freeze_queue_wait(q); | |
183 | } | |
184 | ||
185 | void blk_mq_freeze_queue(struct request_queue *q) | |
186 | { | |
187 | /* | |
188 | * ...just an alias to keep freeze and unfreeze actions balanced | |
189 | * in the blk_mq_* namespace | |
190 | */ | |
191 | blk_freeze_queue(q); | |
192 | } | |
193 | EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); | |
194 | ||
195 | void blk_mq_unfreeze_queue(struct request_queue *q) | |
196 | { | |
197 | int freeze_depth; | |
198 | ||
199 | freeze_depth = atomic_dec_return(&q->mq_freeze_depth); | |
200 | WARN_ON_ONCE(freeze_depth < 0); | |
201 | if (!freeze_depth) { | |
202 | percpu_ref_resurrect(&q->q_usage_counter); | |
203 | wake_up_all(&q->mq_freeze_wq); | |
204 | } | |
205 | } | |
206 | EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); | |
207 | ||
208 | /* | |
209 | * FIXME: replace the scsi_internal_device_*block_nowait() calls in the | |
210 | * mpt3sas driver such that this function can be removed. | |
211 | */ | |
212 | void blk_mq_quiesce_queue_nowait(struct request_queue *q) | |
213 | { | |
214 | blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); | |
215 | } | |
216 | EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); | |
217 | ||
218 | /** | |
219 | * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished | |
220 | * @q: request queue. | |
221 | * | |
222 | * Note: this function does not prevent that the struct request end_io() | |
223 | * callback function is invoked. Once this function is returned, we make | |
224 | * sure no dispatch can happen until the queue is unquiesced via | |
225 | * blk_mq_unquiesce_queue(). | |
226 | */ | |
227 | void blk_mq_quiesce_queue(struct request_queue *q) | |
228 | { | |
229 | struct blk_mq_hw_ctx *hctx; | |
230 | unsigned int i; | |
231 | bool rcu = false; | |
232 | ||
233 | blk_mq_quiesce_queue_nowait(q); | |
234 | ||
235 | queue_for_each_hw_ctx(q, hctx, i) { | |
236 | if (hctx->flags & BLK_MQ_F_BLOCKING) | |
237 | synchronize_srcu(hctx->srcu); | |
238 | else | |
239 | rcu = true; | |
240 | } | |
241 | if (rcu) | |
242 | synchronize_rcu(); | |
243 | } | |
244 | EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); | |
245 | ||
246 | /* | |
247 | * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue() | |
248 | * @q: request queue. | |
249 | * | |
250 | * This function recovers queue into the state before quiescing | |
251 | * which is done by blk_mq_quiesce_queue. | |
252 | */ | |
253 | void blk_mq_unquiesce_queue(struct request_queue *q) | |
254 | { | |
255 | blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); | |
256 | ||
257 | /* dispatch requests which are inserted during quiescing */ | |
258 | blk_mq_run_hw_queues(q, true); | |
259 | } | |
260 | EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); | |
261 | ||
262 | void blk_mq_wake_waiters(struct request_queue *q) | |
263 | { | |
264 | struct blk_mq_hw_ctx *hctx; | |
265 | unsigned int i; | |
266 | ||
267 | queue_for_each_hw_ctx(q, hctx, i) | |
268 | if (blk_mq_hw_queue_mapped(hctx)) | |
269 | blk_mq_tag_wakeup_all(hctx->tags, true); | |
270 | } | |
271 | ||
272 | bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx) | |
273 | { | |
274 | return blk_mq_has_free_tags(hctx->tags); | |
275 | } | |
276 | EXPORT_SYMBOL(blk_mq_can_queue); | |
277 | ||
278 | static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, | |
279 | unsigned int tag, unsigned int op) | |
280 | { | |
281 | struct blk_mq_tags *tags = blk_mq_tags_from_data(data); | |
282 | struct request *rq = tags->static_rqs[tag]; | |
283 | req_flags_t rq_flags = 0; | |
284 | ||
285 | if (data->flags & BLK_MQ_REQ_INTERNAL) { | |
286 | rq->tag = -1; | |
287 | rq->internal_tag = tag; | |
288 | } else { | |
289 | if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) { | |
290 | rq_flags = RQF_MQ_INFLIGHT; | |
291 | atomic_inc(&data->hctx->nr_active); | |
292 | } | |
293 | rq->tag = tag; | |
294 | rq->internal_tag = -1; | |
295 | data->hctx->tags->rqs[rq->tag] = rq; | |
296 | } | |
297 | ||
298 | /* csd/requeue_work/fifo_time is initialized before use */ | |
299 | rq->q = data->q; | |
300 | rq->mq_ctx = data->ctx; | |
301 | rq->rq_flags = rq_flags; | |
302 | rq->cpu = -1; | |
303 | rq->cmd_flags = op; | |
304 | if (data->flags & BLK_MQ_REQ_PREEMPT) | |
305 | rq->rq_flags |= RQF_PREEMPT; | |
306 | if (blk_queue_io_stat(data->q)) | |
307 | rq->rq_flags |= RQF_IO_STAT; | |
308 | INIT_LIST_HEAD(&rq->queuelist); | |
309 | INIT_HLIST_NODE(&rq->hash); | |
310 | RB_CLEAR_NODE(&rq->rb_node); | |
311 | rq->rq_disk = NULL; | |
312 | rq->part = NULL; | |
313 | rq->start_time_ns = ktime_get_ns(); | |
314 | rq->io_start_time_ns = 0; | |
315 | rq->nr_phys_segments = 0; | |
316 | #if defined(CONFIG_BLK_DEV_INTEGRITY) | |
317 | rq->nr_integrity_segments = 0; | |
318 | #endif | |
319 | rq->special = NULL; | |
320 | /* tag was already set */ | |
321 | rq->extra_len = 0; | |
322 | rq->__deadline = 0; | |
323 | ||
324 | INIT_LIST_HEAD(&rq->timeout_list); | |
325 | rq->timeout = 0; | |
326 | ||
327 | rq->end_io = NULL; | |
328 | rq->end_io_data = NULL; | |
329 | rq->next_rq = NULL; | |
330 | ||
331 | #ifdef CONFIG_BLK_CGROUP | |
332 | rq->rl = NULL; | |
333 | #endif | |
334 | ||
335 | data->ctx->rq_dispatched[op_is_sync(op)]++; | |
336 | refcount_set(&rq->ref, 1); | |
337 | return rq; | |
338 | } | |
339 | ||
340 | static struct request *blk_mq_get_request(struct request_queue *q, | |
341 | struct bio *bio, unsigned int op, | |
342 | struct blk_mq_alloc_data *data) | |
343 | { | |
344 | struct elevator_queue *e = q->elevator; | |
345 | struct request *rq; | |
346 | unsigned int tag; | |
347 | bool put_ctx_on_error = false; | |
348 | ||
349 | blk_queue_enter_live(q); | |
350 | data->q = q; | |
351 | if (likely(!data->ctx)) { | |
352 | data->ctx = blk_mq_get_ctx(q); | |
353 | put_ctx_on_error = true; | |
354 | } | |
355 | if (likely(!data->hctx)) | |
356 | data->hctx = blk_mq_map_queue(q, data->ctx->cpu); | |
357 | if (op & REQ_NOWAIT) | |
358 | data->flags |= BLK_MQ_REQ_NOWAIT; | |
359 | ||
360 | if (e) { | |
361 | data->flags |= BLK_MQ_REQ_INTERNAL; | |
362 | ||
363 | /* | |
364 | * Flush requests are special and go directly to the | |
365 | * dispatch list. Don't include reserved tags in the | |
366 | * limiting, as it isn't useful. | |
367 | */ | |
368 | if (!op_is_flush(op) && e->type->ops.mq.limit_depth && | |
369 | !(data->flags & BLK_MQ_REQ_RESERVED)) | |
370 | e->type->ops.mq.limit_depth(op, data); | |
371 | } else { | |
372 | blk_mq_tag_busy(data->hctx); | |
373 | } | |
374 | ||
375 | tag = blk_mq_get_tag(data); | |
376 | if (tag == BLK_MQ_TAG_FAIL) { | |
377 | if (put_ctx_on_error) { | |
378 | blk_mq_put_ctx(data->ctx); | |
379 | data->ctx = NULL; | |
380 | } | |
381 | blk_queue_exit(q); | |
382 | return NULL; | |
383 | } | |
384 | ||
385 | rq = blk_mq_rq_ctx_init(data, tag, op); | |
386 | if (!op_is_flush(op)) { | |
387 | rq->elv.icq = NULL; | |
388 | if (e && e->type->ops.mq.prepare_request) { | |
389 | if (e->type->icq_cache && rq_ioc(bio)) | |
390 | blk_mq_sched_assign_ioc(rq, bio); | |
391 | ||
392 | e->type->ops.mq.prepare_request(rq, bio); | |
393 | rq->rq_flags |= RQF_ELVPRIV; | |
394 | } | |
395 | } | |
396 | data->hctx->queued++; | |
397 | return rq; | |
398 | } | |
399 | ||
400 | struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op, | |
401 | blk_mq_req_flags_t flags) | |
402 | { | |
403 | struct blk_mq_alloc_data alloc_data = { .flags = flags }; | |
404 | struct request *rq; | |
405 | int ret; | |
406 | ||
407 | ret = blk_queue_enter(q, flags); | |
408 | if (ret) | |
409 | return ERR_PTR(ret); | |
410 | ||
411 | rq = blk_mq_get_request(q, NULL, op, &alloc_data); | |
412 | blk_queue_exit(q); | |
413 | ||
414 | if (!rq) | |
415 | return ERR_PTR(-EWOULDBLOCK); | |
416 | ||
417 | blk_mq_put_ctx(alloc_data.ctx); | |
418 | ||
419 | rq->__data_len = 0; | |
420 | rq->__sector = (sector_t) -1; | |
421 | rq->bio = rq->biotail = NULL; | |
422 | return rq; | |
423 | } | |
424 | EXPORT_SYMBOL(blk_mq_alloc_request); | |
425 | ||
426 | struct request *blk_mq_alloc_request_hctx(struct request_queue *q, | |
427 | unsigned int op, blk_mq_req_flags_t flags, unsigned int hctx_idx) | |
428 | { | |
429 | struct blk_mq_alloc_data alloc_data = { .flags = flags }; | |
430 | struct request *rq; | |
431 | unsigned int cpu; | |
432 | int ret; | |
433 | ||
434 | /* | |
435 | * If the tag allocator sleeps we could get an allocation for a | |
436 | * different hardware context. No need to complicate the low level | |
437 | * allocator for this for the rare use case of a command tied to | |
438 | * a specific queue. | |
439 | */ | |
440 | if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT))) | |
441 | return ERR_PTR(-EINVAL); | |
442 | ||
443 | if (hctx_idx >= q->nr_hw_queues) | |
444 | return ERR_PTR(-EIO); | |
445 | ||
446 | ret = blk_queue_enter(q, flags); | |
447 | if (ret) | |
448 | return ERR_PTR(ret); | |
449 | ||
450 | /* | |
451 | * Check if the hardware context is actually mapped to anything. | |
452 | * If not tell the caller that it should skip this queue. | |
453 | */ | |
454 | alloc_data.hctx = q->queue_hw_ctx[hctx_idx]; | |
455 | if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) { | |
456 | blk_queue_exit(q); | |
457 | return ERR_PTR(-EXDEV); | |
458 | } | |
459 | cpu = cpumask_first_and(alloc_data.hctx->cpumask, cpu_online_mask); | |
460 | alloc_data.ctx = __blk_mq_get_ctx(q, cpu); | |
461 | ||
462 | rq = blk_mq_get_request(q, NULL, op, &alloc_data); | |
463 | blk_queue_exit(q); | |
464 | ||
465 | if (!rq) | |
466 | return ERR_PTR(-EWOULDBLOCK); | |
467 | ||
468 | return rq; | |
469 | } | |
470 | EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx); | |
471 | ||
472 | static void __blk_mq_free_request(struct request *rq) | |
473 | { | |
474 | struct request_queue *q = rq->q; | |
475 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
476 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); | |
477 | const int sched_tag = rq->internal_tag; | |
478 | ||
479 | blk_pm_mark_last_busy(rq); | |
480 | if (rq->tag != -1) | |
481 | blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag); | |
482 | if (sched_tag != -1) | |
483 | blk_mq_put_tag(hctx, hctx->sched_tags, ctx, sched_tag); | |
484 | blk_mq_sched_restart(hctx); | |
485 | blk_queue_exit(q); | |
486 | } | |
487 | ||
488 | void blk_mq_free_request(struct request *rq) | |
489 | { | |
490 | struct request_queue *q = rq->q; | |
491 | struct elevator_queue *e = q->elevator; | |
492 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
493 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); | |
494 | ||
495 | if (rq->rq_flags & RQF_ELVPRIV) { | |
496 | if (e && e->type->ops.mq.finish_request) | |
497 | e->type->ops.mq.finish_request(rq); | |
498 | if (rq->elv.icq) { | |
499 | put_io_context(rq->elv.icq->ioc); | |
500 | rq->elv.icq = NULL; | |
501 | } | |
502 | } | |
503 | ||
504 | ctx->rq_completed[rq_is_sync(rq)]++; | |
505 | if (rq->rq_flags & RQF_MQ_INFLIGHT) | |
506 | atomic_dec(&hctx->nr_active); | |
507 | ||
508 | if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq))) | |
509 | laptop_io_completion(q->backing_dev_info); | |
510 | ||
511 | rq_qos_done(q, rq); | |
512 | ||
513 | if (blk_rq_rl(rq)) | |
514 | blk_put_rl(blk_rq_rl(rq)); | |
515 | ||
516 | WRITE_ONCE(rq->state, MQ_RQ_IDLE); | |
517 | if (refcount_dec_and_test(&rq->ref)) | |
518 | __blk_mq_free_request(rq); | |
519 | } | |
520 | EXPORT_SYMBOL_GPL(blk_mq_free_request); | |
521 | ||
522 | inline void __blk_mq_end_request(struct request *rq, blk_status_t error) | |
523 | { | |
524 | u64 now = ktime_get_ns(); | |
525 | ||
526 | if (rq->rq_flags & RQF_STATS) { | |
527 | blk_mq_poll_stats_start(rq->q); | |
528 | blk_stat_add(rq, now); | |
529 | } | |
530 | ||
531 | if (rq->internal_tag != -1) | |
532 | blk_mq_sched_completed_request(rq, now); | |
533 | ||
534 | blk_account_io_done(rq, now); | |
535 | ||
536 | if (rq->end_io) { | |
537 | rq_qos_done(rq->q, rq); | |
538 | rq->end_io(rq, error); | |
539 | } else { | |
540 | if (unlikely(blk_bidi_rq(rq))) | |
541 | blk_mq_free_request(rq->next_rq); | |
542 | blk_mq_free_request(rq); | |
543 | } | |
544 | } | |
545 | EXPORT_SYMBOL(__blk_mq_end_request); | |
546 | ||
547 | void blk_mq_end_request(struct request *rq, blk_status_t error) | |
548 | { | |
549 | if (blk_update_request(rq, error, blk_rq_bytes(rq))) | |
550 | BUG(); | |
551 | __blk_mq_end_request(rq, error); | |
552 | } | |
553 | EXPORT_SYMBOL(blk_mq_end_request); | |
554 | ||
555 | static void __blk_mq_complete_request_remote(void *data) | |
556 | { | |
557 | struct request *rq = data; | |
558 | ||
559 | rq->q->softirq_done_fn(rq); | |
560 | } | |
561 | ||
562 | static void __blk_mq_complete_request(struct request *rq) | |
563 | { | |
564 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
565 | bool shared = false; | |
566 | int cpu; | |
567 | ||
568 | if (!blk_mq_mark_complete(rq)) | |
569 | return; | |
570 | ||
571 | if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) { | |
572 | rq->q->softirq_done_fn(rq); | |
573 | return; | |
574 | } | |
575 | ||
576 | cpu = get_cpu(); | |
577 | if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags)) | |
578 | shared = cpus_share_cache(cpu, ctx->cpu); | |
579 | ||
580 | if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { | |
581 | rq->csd.func = __blk_mq_complete_request_remote; | |
582 | rq->csd.info = rq; | |
583 | rq->csd.flags = 0; | |
584 | smp_call_function_single_async(ctx->cpu, &rq->csd); | |
585 | } else { | |
586 | rq->q->softirq_done_fn(rq); | |
587 | } | |
588 | put_cpu(); | |
589 | } | |
590 | ||
591 | static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx) | |
592 | __releases(hctx->srcu) | |
593 | { | |
594 | if (!(hctx->flags & BLK_MQ_F_BLOCKING)) | |
595 | rcu_read_unlock(); | |
596 | else | |
597 | srcu_read_unlock(hctx->srcu, srcu_idx); | |
598 | } | |
599 | ||
600 | static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx) | |
601 | __acquires(hctx->srcu) | |
602 | { | |
603 | if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { | |
604 | /* shut up gcc false positive */ | |
605 | *srcu_idx = 0; | |
606 | rcu_read_lock(); | |
607 | } else | |
608 | *srcu_idx = srcu_read_lock(hctx->srcu); | |
609 | } | |
610 | ||
611 | /** | |
612 | * blk_mq_complete_request - end I/O on a request | |
613 | * @rq: the request being processed | |
614 | * | |
615 | * Description: | |
616 | * Ends all I/O on a request. It does not handle partial completions. | |
617 | * The actual completion happens out-of-order, through a IPI handler. | |
618 | **/ | |
619 | void blk_mq_complete_request(struct request *rq) | |
620 | { | |
621 | if (unlikely(blk_should_fake_timeout(rq->q))) | |
622 | return; | |
623 | __blk_mq_complete_request(rq); | |
624 | } | |
625 | EXPORT_SYMBOL(blk_mq_complete_request); | |
626 | ||
627 | int blk_mq_request_started(struct request *rq) | |
628 | { | |
629 | return blk_mq_rq_state(rq) != MQ_RQ_IDLE; | |
630 | } | |
631 | EXPORT_SYMBOL_GPL(blk_mq_request_started); | |
632 | ||
633 | void blk_mq_start_request(struct request *rq) | |
634 | { | |
635 | struct request_queue *q = rq->q; | |
636 | ||
637 | blk_mq_sched_started_request(rq); | |
638 | ||
639 | trace_block_rq_issue(q, rq); | |
640 | ||
641 | if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) { | |
642 | rq->io_start_time_ns = ktime_get_ns(); | |
643 | #ifdef CONFIG_BLK_DEV_THROTTLING_LOW | |
644 | rq->throtl_size = blk_rq_sectors(rq); | |
645 | #endif | |
646 | rq->rq_flags |= RQF_STATS; | |
647 | rq_qos_issue(q, rq); | |
648 | } | |
649 | ||
650 | WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE); | |
651 | ||
652 | blk_add_timer(rq); | |
653 | WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT); | |
654 | ||
655 | if (q->dma_drain_size && blk_rq_bytes(rq)) { | |
656 | /* | |
657 | * Make sure space for the drain appears. We know we can do | |
658 | * this because max_hw_segments has been adjusted to be one | |
659 | * fewer than the device can handle. | |
660 | */ | |
661 | rq->nr_phys_segments++; | |
662 | } | |
663 | } | |
664 | EXPORT_SYMBOL(blk_mq_start_request); | |
665 | ||
666 | static void __blk_mq_requeue_request(struct request *rq) | |
667 | { | |
668 | struct request_queue *q = rq->q; | |
669 | ||
670 | blk_mq_put_driver_tag(rq); | |
671 | ||
672 | trace_block_rq_requeue(q, rq); | |
673 | rq_qos_requeue(q, rq); | |
674 | ||
675 | if (blk_mq_request_started(rq)) { | |
676 | WRITE_ONCE(rq->state, MQ_RQ_IDLE); | |
677 | rq->rq_flags &= ~RQF_TIMED_OUT; | |
678 | if (q->dma_drain_size && blk_rq_bytes(rq)) | |
679 | rq->nr_phys_segments--; | |
680 | } | |
681 | } | |
682 | ||
683 | void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list) | |
684 | { | |
685 | __blk_mq_requeue_request(rq); | |
686 | ||
687 | /* this request will be re-inserted to io scheduler queue */ | |
688 | blk_mq_sched_requeue_request(rq); | |
689 | ||
690 | BUG_ON(blk_queued_rq(rq)); | |
691 | blk_mq_add_to_requeue_list(rq, true, kick_requeue_list); | |
692 | } | |
693 | EXPORT_SYMBOL(blk_mq_requeue_request); | |
694 | ||
695 | static void blk_mq_requeue_work(struct work_struct *work) | |
696 | { | |
697 | struct request_queue *q = | |
698 | container_of(work, struct request_queue, requeue_work.work); | |
699 | LIST_HEAD(rq_list); | |
700 | struct request *rq, *next; | |
701 | ||
702 | spin_lock_irq(&q->requeue_lock); | |
703 | list_splice_init(&q->requeue_list, &rq_list); | |
704 | spin_unlock_irq(&q->requeue_lock); | |
705 | ||
706 | list_for_each_entry_safe(rq, next, &rq_list, queuelist) { | |
707 | if (!(rq->rq_flags & RQF_SOFTBARRIER)) | |
708 | continue; | |
709 | ||
710 | rq->rq_flags &= ~RQF_SOFTBARRIER; | |
711 | list_del_init(&rq->queuelist); | |
712 | blk_mq_sched_insert_request(rq, true, false, false); | |
713 | } | |
714 | ||
715 | while (!list_empty(&rq_list)) { | |
716 | rq = list_entry(rq_list.next, struct request, queuelist); | |
717 | list_del_init(&rq->queuelist); | |
718 | blk_mq_sched_insert_request(rq, false, false, false); | |
719 | } | |
720 | ||
721 | blk_mq_run_hw_queues(q, false); | |
722 | } | |
723 | ||
724 | void blk_mq_add_to_requeue_list(struct request *rq, bool at_head, | |
725 | bool kick_requeue_list) | |
726 | { | |
727 | struct request_queue *q = rq->q; | |
728 | unsigned long flags; | |
729 | ||
730 | /* | |
731 | * We abuse this flag that is otherwise used by the I/O scheduler to | |
732 | * request head insertion from the workqueue. | |
733 | */ | |
734 | BUG_ON(rq->rq_flags & RQF_SOFTBARRIER); | |
735 | ||
736 | spin_lock_irqsave(&q->requeue_lock, flags); | |
737 | if (at_head) { | |
738 | rq->rq_flags |= RQF_SOFTBARRIER; | |
739 | list_add(&rq->queuelist, &q->requeue_list); | |
740 | } else { | |
741 | list_add_tail(&rq->queuelist, &q->requeue_list); | |
742 | } | |
743 | spin_unlock_irqrestore(&q->requeue_lock, flags); | |
744 | ||
745 | if (kick_requeue_list) | |
746 | blk_mq_kick_requeue_list(q); | |
747 | } | |
748 | EXPORT_SYMBOL(blk_mq_add_to_requeue_list); | |
749 | ||
750 | void blk_mq_kick_requeue_list(struct request_queue *q) | |
751 | { | |
752 | kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0); | |
753 | } | |
754 | EXPORT_SYMBOL(blk_mq_kick_requeue_list); | |
755 | ||
756 | void blk_mq_delay_kick_requeue_list(struct request_queue *q, | |
757 | unsigned long msecs) | |
758 | { | |
759 | kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, | |
760 | msecs_to_jiffies(msecs)); | |
761 | } | |
762 | EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list); | |
763 | ||
764 | struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) | |
765 | { | |
766 | if (tag < tags->nr_tags) { | |
767 | prefetch(tags->rqs[tag]); | |
768 | return tags->rqs[tag]; | |
769 | } | |
770 | ||
771 | return NULL; | |
772 | } | |
773 | EXPORT_SYMBOL(blk_mq_tag_to_rq); | |
774 | ||
775 | static void blk_mq_rq_timed_out(struct request *req, bool reserved) | |
776 | { | |
777 | req->rq_flags |= RQF_TIMED_OUT; | |
778 | if (req->q->mq_ops->timeout) { | |
779 | enum blk_eh_timer_return ret; | |
780 | ||
781 | ret = req->q->mq_ops->timeout(req, reserved); | |
782 | if (ret == BLK_EH_DONE) | |
783 | return; | |
784 | WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER); | |
785 | } | |
786 | ||
787 | blk_add_timer(req); | |
788 | } | |
789 | ||
790 | static bool blk_mq_req_expired(struct request *rq, unsigned long *next) | |
791 | { | |
792 | unsigned long deadline; | |
793 | ||
794 | if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT) | |
795 | return false; | |
796 | if (rq->rq_flags & RQF_TIMED_OUT) | |
797 | return false; | |
798 | ||
799 | deadline = blk_rq_deadline(rq); | |
800 | if (time_after_eq(jiffies, deadline)) | |
801 | return true; | |
802 | ||
803 | if (*next == 0) | |
804 | *next = deadline; | |
805 | else if (time_after(*next, deadline)) | |
806 | *next = deadline; | |
807 | return false; | |
808 | } | |
809 | ||
810 | static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, | |
811 | struct request *rq, void *priv, bool reserved) | |
812 | { | |
813 | unsigned long *next = priv; | |
814 | ||
815 | /* | |
816 | * Just do a quick check if it is expired before locking the request in | |
817 | * so we're not unnecessarilly synchronizing across CPUs. | |
818 | */ | |
819 | if (!blk_mq_req_expired(rq, next)) | |
820 | return; | |
821 | ||
822 | /* | |
823 | * We have reason to believe the request may be expired. Take a | |
824 | * reference on the request to lock this request lifetime into its | |
825 | * currently allocated context to prevent it from being reallocated in | |
826 | * the event the completion by-passes this timeout handler. | |
827 | * | |
828 | * If the reference was already released, then the driver beat the | |
829 | * timeout handler to posting a natural completion. | |
830 | */ | |
831 | if (!refcount_inc_not_zero(&rq->ref)) | |
832 | return; | |
833 | ||
834 | /* | |
835 | * The request is now locked and cannot be reallocated underneath the | |
836 | * timeout handler's processing. Re-verify this exact request is truly | |
837 | * expired; if it is not expired, then the request was completed and | |
838 | * reallocated as a new request. | |
839 | */ | |
840 | if (blk_mq_req_expired(rq, next)) | |
841 | blk_mq_rq_timed_out(rq, reserved); | |
842 | if (refcount_dec_and_test(&rq->ref)) | |
843 | __blk_mq_free_request(rq); | |
844 | } | |
845 | ||
846 | static void blk_mq_timeout_work(struct work_struct *work) | |
847 | { | |
848 | struct request_queue *q = | |
849 | container_of(work, struct request_queue, timeout_work); | |
850 | unsigned long next = 0; | |
851 | struct blk_mq_hw_ctx *hctx; | |
852 | int i; | |
853 | ||
854 | /* A deadlock might occur if a request is stuck requiring a | |
855 | * timeout at the same time a queue freeze is waiting | |
856 | * completion, since the timeout code would not be able to | |
857 | * acquire the queue reference here. | |
858 | * | |
859 | * That's why we don't use blk_queue_enter here; instead, we use | |
860 | * percpu_ref_tryget directly, because we need to be able to | |
861 | * obtain a reference even in the short window between the queue | |
862 | * starting to freeze, by dropping the first reference in | |
863 | * blk_freeze_queue_start, and the moment the last request is | |
864 | * consumed, marked by the instant q_usage_counter reaches | |
865 | * zero. | |
866 | */ | |
867 | if (!percpu_ref_tryget(&q->q_usage_counter)) | |
868 | return; | |
869 | ||
870 | blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &next); | |
871 | ||
872 | if (next != 0) { | |
873 | mod_timer(&q->timeout, next); | |
874 | } else { | |
875 | /* | |
876 | * Request timeouts are handled as a forward rolling timer. If | |
877 | * we end up here it means that no requests are pending and | |
878 | * also that no request has been pending for a while. Mark | |
879 | * each hctx as idle. | |
880 | */ | |
881 | queue_for_each_hw_ctx(q, hctx, i) { | |
882 | /* the hctx may be unmapped, so check it here */ | |
883 | if (blk_mq_hw_queue_mapped(hctx)) | |
884 | blk_mq_tag_idle(hctx); | |
885 | } | |
886 | } | |
887 | blk_queue_exit(q); | |
888 | } | |
889 | ||
890 | struct flush_busy_ctx_data { | |
891 | struct blk_mq_hw_ctx *hctx; | |
892 | struct list_head *list; | |
893 | }; | |
894 | ||
895 | static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data) | |
896 | { | |
897 | struct flush_busy_ctx_data *flush_data = data; | |
898 | struct blk_mq_hw_ctx *hctx = flush_data->hctx; | |
899 | struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; | |
900 | ||
901 | spin_lock(&ctx->lock); | |
902 | list_splice_tail_init(&ctx->rq_list, flush_data->list); | |
903 | sbitmap_clear_bit(sb, bitnr); | |
904 | spin_unlock(&ctx->lock); | |
905 | return true; | |
906 | } | |
907 | ||
908 | /* | |
909 | * Process software queues that have been marked busy, splicing them | |
910 | * to the for-dispatch | |
911 | */ | |
912 | void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) | |
913 | { | |
914 | struct flush_busy_ctx_data data = { | |
915 | .hctx = hctx, | |
916 | .list = list, | |
917 | }; | |
918 | ||
919 | sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data); | |
920 | } | |
921 | EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs); | |
922 | ||
923 | struct dispatch_rq_data { | |
924 | struct blk_mq_hw_ctx *hctx; | |
925 | struct request *rq; | |
926 | }; | |
927 | ||
928 | static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr, | |
929 | void *data) | |
930 | { | |
931 | struct dispatch_rq_data *dispatch_data = data; | |
932 | struct blk_mq_hw_ctx *hctx = dispatch_data->hctx; | |
933 | struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; | |
934 | ||
935 | spin_lock(&ctx->lock); | |
936 | if (!list_empty(&ctx->rq_list)) { | |
937 | dispatch_data->rq = list_entry_rq(ctx->rq_list.next); | |
938 | list_del_init(&dispatch_data->rq->queuelist); | |
939 | if (list_empty(&ctx->rq_list)) | |
940 | sbitmap_clear_bit(sb, bitnr); | |
941 | } | |
942 | spin_unlock(&ctx->lock); | |
943 | ||
944 | return !dispatch_data->rq; | |
945 | } | |
946 | ||
947 | struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx, | |
948 | struct blk_mq_ctx *start) | |
949 | { | |
950 | unsigned off = start ? start->index_hw : 0; | |
951 | struct dispatch_rq_data data = { | |
952 | .hctx = hctx, | |
953 | .rq = NULL, | |
954 | }; | |
955 | ||
956 | __sbitmap_for_each_set(&hctx->ctx_map, off, | |
957 | dispatch_rq_from_ctx, &data); | |
958 | ||
959 | return data.rq; | |
960 | } | |
961 | ||
962 | static inline unsigned int queued_to_index(unsigned int queued) | |
963 | { | |
964 | if (!queued) | |
965 | return 0; | |
966 | ||
967 | return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1); | |
968 | } | |
969 | ||
970 | bool blk_mq_get_driver_tag(struct request *rq) | |
971 | { | |
972 | struct blk_mq_alloc_data data = { | |
973 | .q = rq->q, | |
974 | .hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu), | |
975 | .flags = BLK_MQ_REQ_NOWAIT, | |
976 | }; | |
977 | bool shared; | |
978 | ||
979 | if (rq->tag != -1) | |
980 | goto done; | |
981 | ||
982 | if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag)) | |
983 | data.flags |= BLK_MQ_REQ_RESERVED; | |
984 | ||
985 | shared = blk_mq_tag_busy(data.hctx); | |
986 | rq->tag = blk_mq_get_tag(&data); | |
987 | if (rq->tag >= 0) { | |
988 | if (shared) { | |
989 | rq->rq_flags |= RQF_MQ_INFLIGHT; | |
990 | atomic_inc(&data.hctx->nr_active); | |
991 | } | |
992 | data.hctx->tags->rqs[rq->tag] = rq; | |
993 | } | |
994 | ||
995 | done: | |
996 | return rq->tag != -1; | |
997 | } | |
998 | ||
999 | static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, | |
1000 | int flags, void *key) | |
1001 | { | |
1002 | struct blk_mq_hw_ctx *hctx; | |
1003 | ||
1004 | hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait); | |
1005 | ||
1006 | spin_lock(&hctx->dispatch_wait_lock); | |
1007 | list_del_init(&wait->entry); | |
1008 | spin_unlock(&hctx->dispatch_wait_lock); | |
1009 | ||
1010 | blk_mq_run_hw_queue(hctx, true); | |
1011 | return 1; | |
1012 | } | |
1013 | ||
1014 | /* | |
1015 | * Mark us waiting for a tag. For shared tags, this involves hooking us into | |
1016 | * the tag wakeups. For non-shared tags, we can simply mark us needing a | |
1017 | * restart. For both cases, take care to check the condition again after | |
1018 | * marking us as waiting. | |
1019 | */ | |
1020 | static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, | |
1021 | struct request *rq) | |
1022 | { | |
1023 | struct wait_queue_head *wq; | |
1024 | wait_queue_entry_t *wait; | |
1025 | bool ret; | |
1026 | ||
1027 | if (!(hctx->flags & BLK_MQ_F_TAG_SHARED)) { | |
1028 | if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) | |
1029 | set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); | |
1030 | ||
1031 | /* | |
1032 | * It's possible that a tag was freed in the window between the | |
1033 | * allocation failure and adding the hardware queue to the wait | |
1034 | * queue. | |
1035 | * | |
1036 | * Don't clear RESTART here, someone else could have set it. | |
1037 | * At most this will cost an extra queue run. | |
1038 | */ | |
1039 | return blk_mq_get_driver_tag(rq); | |
1040 | } | |
1041 | ||
1042 | wait = &hctx->dispatch_wait; | |
1043 | if (!list_empty_careful(&wait->entry)) | |
1044 | return false; | |
1045 | ||
1046 | wq = &bt_wait_ptr(&hctx->tags->bitmap_tags, hctx)->wait; | |
1047 | ||
1048 | spin_lock_irq(&wq->lock); | |
1049 | spin_lock(&hctx->dispatch_wait_lock); | |
1050 | if (!list_empty(&wait->entry)) { | |
1051 | spin_unlock(&hctx->dispatch_wait_lock); | |
1052 | spin_unlock_irq(&wq->lock); | |
1053 | return false; | |
1054 | } | |
1055 | ||
1056 | wait->flags &= ~WQ_FLAG_EXCLUSIVE; | |
1057 | __add_wait_queue(wq, wait); | |
1058 | ||
1059 | /* | |
1060 | * It's possible that a tag was freed in the window between the | |
1061 | * allocation failure and adding the hardware queue to the wait | |
1062 | * queue. | |
1063 | */ | |
1064 | ret = blk_mq_get_driver_tag(rq); | |
1065 | if (!ret) { | |
1066 | spin_unlock(&hctx->dispatch_wait_lock); | |
1067 | spin_unlock_irq(&wq->lock); | |
1068 | return false; | |
1069 | } | |
1070 | ||
1071 | /* | |
1072 | * We got a tag, remove ourselves from the wait queue to ensure | |
1073 | * someone else gets the wakeup. | |
1074 | */ | |
1075 | list_del_init(&wait->entry); | |
1076 | spin_unlock(&hctx->dispatch_wait_lock); | |
1077 | spin_unlock_irq(&wq->lock); | |
1078 | ||
1079 | return true; | |
1080 | } | |
1081 | ||
1082 | #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8 | |
1083 | #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4 | |
1084 | /* | |
1085 | * Update dispatch busy with the Exponential Weighted Moving Average(EWMA): | |
1086 | * - EWMA is one simple way to compute running average value | |
1087 | * - weight(7/8 and 1/8) is applied so that it can decrease exponentially | |
1088 | * - take 4 as factor for avoiding to get too small(0) result, and this | |
1089 | * factor doesn't matter because EWMA decreases exponentially | |
1090 | */ | |
1091 | static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy) | |
1092 | { | |
1093 | unsigned int ewma; | |
1094 | ||
1095 | if (hctx->queue->elevator) | |
1096 | return; | |
1097 | ||
1098 | ewma = hctx->dispatch_busy; | |
1099 | ||
1100 | if (!ewma && !busy) | |
1101 | return; | |
1102 | ||
1103 | ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1; | |
1104 | if (busy) | |
1105 | ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR; | |
1106 | ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT; | |
1107 | ||
1108 | hctx->dispatch_busy = ewma; | |
1109 | } | |
1110 | ||
1111 | #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */ | |
1112 | ||
1113 | /* | |
1114 | * Returns true if we did some work AND can potentially do more. | |
1115 | */ | |
1116 | bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, | |
1117 | bool got_budget) | |
1118 | { | |
1119 | struct blk_mq_hw_ctx *hctx; | |
1120 | struct request *rq, *nxt; | |
1121 | bool no_tag = false; | |
1122 | int errors, queued; | |
1123 | blk_status_t ret = BLK_STS_OK; | |
1124 | ||
1125 | if (list_empty(list)) | |
1126 | return false; | |
1127 | ||
1128 | WARN_ON(!list_is_singular(list) && got_budget); | |
1129 | ||
1130 | /* | |
1131 | * Now process all the entries, sending them to the driver. | |
1132 | */ | |
1133 | errors = queued = 0; | |
1134 | do { | |
1135 | struct blk_mq_queue_data bd; | |
1136 | ||
1137 | rq = list_first_entry(list, struct request, queuelist); | |
1138 | ||
1139 | hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu); | |
1140 | if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) | |
1141 | break; | |
1142 | ||
1143 | if (!blk_mq_get_driver_tag(rq)) { | |
1144 | /* | |
1145 | * The initial allocation attempt failed, so we need to | |
1146 | * rerun the hardware queue when a tag is freed. The | |
1147 | * waitqueue takes care of that. If the queue is run | |
1148 | * before we add this entry back on the dispatch list, | |
1149 | * we'll re-run it below. | |
1150 | */ | |
1151 | if (!blk_mq_mark_tag_wait(hctx, rq)) { | |
1152 | blk_mq_put_dispatch_budget(hctx); | |
1153 | /* | |
1154 | * For non-shared tags, the RESTART check | |
1155 | * will suffice. | |
1156 | */ | |
1157 | if (hctx->flags & BLK_MQ_F_TAG_SHARED) | |
1158 | no_tag = true; | |
1159 | break; | |
1160 | } | |
1161 | } | |
1162 | ||
1163 | list_del_init(&rq->queuelist); | |
1164 | ||
1165 | bd.rq = rq; | |
1166 | ||
1167 | /* | |
1168 | * Flag last if we have no more requests, or if we have more | |
1169 | * but can't assign a driver tag to it. | |
1170 | */ | |
1171 | if (list_empty(list)) | |
1172 | bd.last = true; | |
1173 | else { | |
1174 | nxt = list_first_entry(list, struct request, queuelist); | |
1175 | bd.last = !blk_mq_get_driver_tag(nxt); | |
1176 | } | |
1177 | ||
1178 | ret = q->mq_ops->queue_rq(hctx, &bd); | |
1179 | if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { | |
1180 | /* | |
1181 | * If an I/O scheduler has been configured and we got a | |
1182 | * driver tag for the next request already, free it | |
1183 | * again. | |
1184 | */ | |
1185 | if (!list_empty(list)) { | |
1186 | nxt = list_first_entry(list, struct request, queuelist); | |
1187 | blk_mq_put_driver_tag(nxt); | |
1188 | } | |
1189 | list_add(&rq->queuelist, list); | |
1190 | __blk_mq_requeue_request(rq); | |
1191 | break; | |
1192 | } | |
1193 | ||
1194 | if (unlikely(ret != BLK_STS_OK)) { | |
1195 | errors++; | |
1196 | blk_mq_end_request(rq, BLK_STS_IOERR); | |
1197 | continue; | |
1198 | } | |
1199 | ||
1200 | queued++; | |
1201 | } while (!list_empty(list)); | |
1202 | ||
1203 | hctx->dispatched[queued_to_index(queued)]++; | |
1204 | ||
1205 | /* | |
1206 | * Any items that need requeuing? Stuff them into hctx->dispatch, | |
1207 | * that is where we will continue on next queue run. | |
1208 | */ | |
1209 | if (!list_empty(list)) { | |
1210 | bool needs_restart; | |
1211 | ||
1212 | spin_lock(&hctx->lock); | |
1213 | list_splice_init(list, &hctx->dispatch); | |
1214 | spin_unlock(&hctx->lock); | |
1215 | ||
1216 | /* | |
1217 | * If SCHED_RESTART was set by the caller of this function and | |
1218 | * it is no longer set that means that it was cleared by another | |
1219 | * thread and hence that a queue rerun is needed. | |
1220 | * | |
1221 | * If 'no_tag' is set, that means that we failed getting | |
1222 | * a driver tag with an I/O scheduler attached. If our dispatch | |
1223 | * waitqueue is no longer active, ensure that we run the queue | |
1224 | * AFTER adding our entries back to the list. | |
1225 | * | |
1226 | * If no I/O scheduler has been configured it is possible that | |
1227 | * the hardware queue got stopped and restarted before requests | |
1228 | * were pushed back onto the dispatch list. Rerun the queue to | |
1229 | * avoid starvation. Notes: | |
1230 | * - blk_mq_run_hw_queue() checks whether or not a queue has | |
1231 | * been stopped before rerunning a queue. | |
1232 | * - Some but not all block drivers stop a queue before | |
1233 | * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq | |
1234 | * and dm-rq. | |
1235 | * | |
1236 | * If driver returns BLK_STS_RESOURCE and SCHED_RESTART | |
1237 | * bit is set, run queue after a delay to avoid IO stalls | |
1238 | * that could otherwise occur if the queue is idle. | |
1239 | */ | |
1240 | needs_restart = blk_mq_sched_needs_restart(hctx); | |
1241 | if (!needs_restart || | |
1242 | (no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) | |
1243 | blk_mq_run_hw_queue(hctx, true); | |
1244 | else if (needs_restart && (ret == BLK_STS_RESOURCE)) | |
1245 | blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY); | |
1246 | ||
1247 | blk_mq_update_dispatch_busy(hctx, true); | |
1248 | return false; | |
1249 | } else | |
1250 | blk_mq_update_dispatch_busy(hctx, false); | |
1251 | ||
1252 | /* | |
1253 | * If the host/device is unable to accept more work, inform the | |
1254 | * caller of that. | |
1255 | */ | |
1256 | if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) | |
1257 | return false; | |
1258 | ||
1259 | return (queued + errors) != 0; | |
1260 | } | |
1261 | ||
1262 | static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) | |
1263 | { | |
1264 | int srcu_idx; | |
1265 | ||
1266 | /* | |
1267 | * We should be running this queue from one of the CPUs that | |
1268 | * are mapped to it. | |
1269 | * | |
1270 | * There are at least two related races now between setting | |
1271 | * hctx->next_cpu from blk_mq_hctx_next_cpu() and running | |
1272 | * __blk_mq_run_hw_queue(): | |
1273 | * | |
1274 | * - hctx->next_cpu is found offline in blk_mq_hctx_next_cpu(), | |
1275 | * but later it becomes online, then this warning is harmless | |
1276 | * at all | |
1277 | * | |
1278 | * - hctx->next_cpu is found online in blk_mq_hctx_next_cpu(), | |
1279 | * but later it becomes offline, then the warning can't be | |
1280 | * triggered, and we depend on blk-mq timeout handler to | |
1281 | * handle dispatched requests to this hctx | |
1282 | */ | |
1283 | if (!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && | |
1284 | cpu_online(hctx->next_cpu)) { | |
1285 | printk(KERN_WARNING "run queue from wrong CPU %d, hctx %s\n", | |
1286 | raw_smp_processor_id(), | |
1287 | cpumask_empty(hctx->cpumask) ? "inactive": "active"); | |
1288 | dump_stack(); | |
1289 | } | |
1290 | ||
1291 | /* | |
1292 | * We can't run the queue inline with ints disabled. Ensure that | |
1293 | * we catch bad users of this early. | |
1294 | */ | |
1295 | WARN_ON_ONCE(in_interrupt()); | |
1296 | ||
1297 | might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); | |
1298 | ||
1299 | hctx_lock(hctx, &srcu_idx); | |
1300 | blk_mq_sched_dispatch_requests(hctx); | |
1301 | hctx_unlock(hctx, srcu_idx); | |
1302 | } | |
1303 | ||
1304 | static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx) | |
1305 | { | |
1306 | int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask); | |
1307 | ||
1308 | if (cpu >= nr_cpu_ids) | |
1309 | cpu = cpumask_first(hctx->cpumask); | |
1310 | return cpu; | |
1311 | } | |
1312 | ||
1313 | /* | |
1314 | * It'd be great if the workqueue API had a way to pass | |
1315 | * in a mask and had some smarts for more clever placement. | |
1316 | * For now we just round-robin here, switching for every | |
1317 | * BLK_MQ_CPU_WORK_BATCH queued items. | |
1318 | */ | |
1319 | static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) | |
1320 | { | |
1321 | bool tried = false; | |
1322 | int next_cpu = hctx->next_cpu; | |
1323 | ||
1324 | if (hctx->queue->nr_hw_queues == 1) | |
1325 | return WORK_CPU_UNBOUND; | |
1326 | ||
1327 | if (--hctx->next_cpu_batch <= 0) { | |
1328 | select_cpu: | |
1329 | next_cpu = cpumask_next_and(next_cpu, hctx->cpumask, | |
1330 | cpu_online_mask); | |
1331 | if (next_cpu >= nr_cpu_ids) | |
1332 | next_cpu = blk_mq_first_mapped_cpu(hctx); | |
1333 | hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; | |
1334 | } | |
1335 | ||
1336 | /* | |
1337 | * Do unbound schedule if we can't find a online CPU for this hctx, | |
1338 | * and it should only happen in the path of handling CPU DEAD. | |
1339 | */ | |
1340 | if (!cpu_online(next_cpu)) { | |
1341 | if (!tried) { | |
1342 | tried = true; | |
1343 | goto select_cpu; | |
1344 | } | |
1345 | ||
1346 | /* | |
1347 | * Make sure to re-select CPU next time once after CPUs | |
1348 | * in hctx->cpumask become online again. | |
1349 | */ | |
1350 | hctx->next_cpu = next_cpu; | |
1351 | hctx->next_cpu_batch = 1; | |
1352 | return WORK_CPU_UNBOUND; | |
1353 | } | |
1354 | ||
1355 | hctx->next_cpu = next_cpu; | |
1356 | return next_cpu; | |
1357 | } | |
1358 | ||
1359 | static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, | |
1360 | unsigned long msecs) | |
1361 | { | |
1362 | if (unlikely(blk_mq_hctx_stopped(hctx))) | |
1363 | return; | |
1364 | ||
1365 | if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) { | |
1366 | int cpu = get_cpu(); | |
1367 | if (cpumask_test_cpu(cpu, hctx->cpumask)) { | |
1368 | __blk_mq_run_hw_queue(hctx); | |
1369 | put_cpu(); | |
1370 | return; | |
1371 | } | |
1372 | ||
1373 | put_cpu(); | |
1374 | } | |
1375 | ||
1376 | kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, | |
1377 | msecs_to_jiffies(msecs)); | |
1378 | } | |
1379 | ||
1380 | void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) | |
1381 | { | |
1382 | __blk_mq_delay_run_hw_queue(hctx, true, msecs); | |
1383 | } | |
1384 | EXPORT_SYMBOL(blk_mq_delay_run_hw_queue); | |
1385 | ||
1386 | bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) | |
1387 | { | |
1388 | int srcu_idx; | |
1389 | bool need_run; | |
1390 | ||
1391 | /* | |
1392 | * When queue is quiesced, we may be switching io scheduler, or | |
1393 | * updating nr_hw_queues, or other things, and we can't run queue | |
1394 | * any more, even __blk_mq_hctx_has_pending() can't be called safely. | |
1395 | * | |
1396 | * And queue will be rerun in blk_mq_unquiesce_queue() if it is | |
1397 | * quiesced. | |
1398 | */ | |
1399 | hctx_lock(hctx, &srcu_idx); | |
1400 | need_run = !blk_queue_quiesced(hctx->queue) && | |
1401 | blk_mq_hctx_has_pending(hctx); | |
1402 | hctx_unlock(hctx, srcu_idx); | |
1403 | ||
1404 | if (need_run) { | |
1405 | __blk_mq_delay_run_hw_queue(hctx, async, 0); | |
1406 | return true; | |
1407 | } | |
1408 | ||
1409 | return false; | |
1410 | } | |
1411 | EXPORT_SYMBOL(blk_mq_run_hw_queue); | |
1412 | ||
1413 | void blk_mq_run_hw_queues(struct request_queue *q, bool async) | |
1414 | { | |
1415 | struct blk_mq_hw_ctx *hctx; | |
1416 | int i; | |
1417 | ||
1418 | queue_for_each_hw_ctx(q, hctx, i) { | |
1419 | if (blk_mq_hctx_stopped(hctx)) | |
1420 | continue; | |
1421 | ||
1422 | blk_mq_run_hw_queue(hctx, async); | |
1423 | } | |
1424 | } | |
1425 | EXPORT_SYMBOL(blk_mq_run_hw_queues); | |
1426 | ||
1427 | /** | |
1428 | * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped | |
1429 | * @q: request queue. | |
1430 | * | |
1431 | * The caller is responsible for serializing this function against | |
1432 | * blk_mq_{start,stop}_hw_queue(). | |
1433 | */ | |
1434 | bool blk_mq_queue_stopped(struct request_queue *q) | |
1435 | { | |
1436 | struct blk_mq_hw_ctx *hctx; | |
1437 | int i; | |
1438 | ||
1439 | queue_for_each_hw_ctx(q, hctx, i) | |
1440 | if (blk_mq_hctx_stopped(hctx)) | |
1441 | return true; | |
1442 | ||
1443 | return false; | |
1444 | } | |
1445 | EXPORT_SYMBOL(blk_mq_queue_stopped); | |
1446 | ||
1447 | /* | |
1448 | * This function is often used for pausing .queue_rq() by driver when | |
1449 | * there isn't enough resource or some conditions aren't satisfied, and | |
1450 | * BLK_STS_RESOURCE is usually returned. | |
1451 | * | |
1452 | * We do not guarantee that dispatch can be drained or blocked | |
1453 | * after blk_mq_stop_hw_queue() returns. Please use | |
1454 | * blk_mq_quiesce_queue() for that requirement. | |
1455 | */ | |
1456 | void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) | |
1457 | { | |
1458 | cancel_delayed_work(&hctx->run_work); | |
1459 | ||
1460 | set_bit(BLK_MQ_S_STOPPED, &hctx->state); | |
1461 | } | |
1462 | EXPORT_SYMBOL(blk_mq_stop_hw_queue); | |
1463 | ||
1464 | /* | |
1465 | * This function is often used for pausing .queue_rq() by driver when | |
1466 | * there isn't enough resource or some conditions aren't satisfied, and | |
1467 | * BLK_STS_RESOURCE is usually returned. | |
1468 | * | |
1469 | * We do not guarantee that dispatch can be drained or blocked | |
1470 | * after blk_mq_stop_hw_queues() returns. Please use | |
1471 | * blk_mq_quiesce_queue() for that requirement. | |
1472 | */ | |
1473 | void blk_mq_stop_hw_queues(struct request_queue *q) | |
1474 | { | |
1475 | struct blk_mq_hw_ctx *hctx; | |
1476 | int i; | |
1477 | ||
1478 | queue_for_each_hw_ctx(q, hctx, i) | |
1479 | blk_mq_stop_hw_queue(hctx); | |
1480 | } | |
1481 | EXPORT_SYMBOL(blk_mq_stop_hw_queues); | |
1482 | ||
1483 | void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) | |
1484 | { | |
1485 | clear_bit(BLK_MQ_S_STOPPED, &hctx->state); | |
1486 | ||
1487 | blk_mq_run_hw_queue(hctx, false); | |
1488 | } | |
1489 | EXPORT_SYMBOL(blk_mq_start_hw_queue); | |
1490 | ||
1491 | void blk_mq_start_hw_queues(struct request_queue *q) | |
1492 | { | |
1493 | struct blk_mq_hw_ctx *hctx; | |
1494 | int i; | |
1495 | ||
1496 | queue_for_each_hw_ctx(q, hctx, i) | |
1497 | blk_mq_start_hw_queue(hctx); | |
1498 | } | |
1499 | EXPORT_SYMBOL(blk_mq_start_hw_queues); | |
1500 | ||
1501 | void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) | |
1502 | { | |
1503 | if (!blk_mq_hctx_stopped(hctx)) | |
1504 | return; | |
1505 | ||
1506 | clear_bit(BLK_MQ_S_STOPPED, &hctx->state); | |
1507 | blk_mq_run_hw_queue(hctx, async); | |
1508 | } | |
1509 | EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue); | |
1510 | ||
1511 | void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) | |
1512 | { | |
1513 | struct blk_mq_hw_ctx *hctx; | |
1514 | int i; | |
1515 | ||
1516 | queue_for_each_hw_ctx(q, hctx, i) | |
1517 | blk_mq_start_stopped_hw_queue(hctx, async); | |
1518 | } | |
1519 | EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); | |
1520 | ||
1521 | static void blk_mq_run_work_fn(struct work_struct *work) | |
1522 | { | |
1523 | struct blk_mq_hw_ctx *hctx; | |
1524 | ||
1525 | hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); | |
1526 | ||
1527 | /* | |
1528 | * If we are stopped, don't run the queue. | |
1529 | */ | |
1530 | if (test_bit(BLK_MQ_S_STOPPED, &hctx->state)) | |
1531 | return; | |
1532 | ||
1533 | __blk_mq_run_hw_queue(hctx); | |
1534 | } | |
1535 | ||
1536 | static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx, | |
1537 | struct request *rq, | |
1538 | bool at_head) | |
1539 | { | |
1540 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
1541 | ||
1542 | lockdep_assert_held(&ctx->lock); | |
1543 | ||
1544 | trace_block_rq_insert(hctx->queue, rq); | |
1545 | ||
1546 | if (at_head) | |
1547 | list_add(&rq->queuelist, &ctx->rq_list); | |
1548 | else | |
1549 | list_add_tail(&rq->queuelist, &ctx->rq_list); | |
1550 | } | |
1551 | ||
1552 | void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, | |
1553 | bool at_head) | |
1554 | { | |
1555 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
1556 | ||
1557 | lockdep_assert_held(&ctx->lock); | |
1558 | ||
1559 | __blk_mq_insert_req_list(hctx, rq, at_head); | |
1560 | blk_mq_hctx_mark_pending(hctx, ctx); | |
1561 | } | |
1562 | ||
1563 | /* | |
1564 | * Should only be used carefully, when the caller knows we want to | |
1565 | * bypass a potential IO scheduler on the target device. | |
1566 | */ | |
1567 | void blk_mq_request_bypass_insert(struct request *rq, bool run_queue) | |
1568 | { | |
1569 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
1570 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(rq->q, ctx->cpu); | |
1571 | ||
1572 | spin_lock(&hctx->lock); | |
1573 | list_add_tail(&rq->queuelist, &hctx->dispatch); | |
1574 | spin_unlock(&hctx->lock); | |
1575 | ||
1576 | if (run_queue) | |
1577 | blk_mq_run_hw_queue(hctx, false); | |
1578 | } | |
1579 | ||
1580 | void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx, | |
1581 | struct list_head *list) | |
1582 | ||
1583 | { | |
1584 | struct request *rq; | |
1585 | ||
1586 | /* | |
1587 | * preemption doesn't flush plug list, so it's possible ctx->cpu is | |
1588 | * offline now | |
1589 | */ | |
1590 | list_for_each_entry(rq, list, queuelist) { | |
1591 | BUG_ON(rq->mq_ctx != ctx); | |
1592 | trace_block_rq_insert(hctx->queue, rq); | |
1593 | } | |
1594 | ||
1595 | spin_lock(&ctx->lock); | |
1596 | list_splice_tail_init(list, &ctx->rq_list); | |
1597 | blk_mq_hctx_mark_pending(hctx, ctx); | |
1598 | spin_unlock(&ctx->lock); | |
1599 | } | |
1600 | ||
1601 | static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b) | |
1602 | { | |
1603 | struct request *rqa = container_of(a, struct request, queuelist); | |
1604 | struct request *rqb = container_of(b, struct request, queuelist); | |
1605 | ||
1606 | return !(rqa->mq_ctx < rqb->mq_ctx || | |
1607 | (rqa->mq_ctx == rqb->mq_ctx && | |
1608 | blk_rq_pos(rqa) < blk_rq_pos(rqb))); | |
1609 | } | |
1610 | ||
1611 | void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) | |
1612 | { | |
1613 | struct blk_mq_ctx *this_ctx; | |
1614 | struct request_queue *this_q; | |
1615 | struct request *rq; | |
1616 | LIST_HEAD(list); | |
1617 | LIST_HEAD(ctx_list); | |
1618 | unsigned int depth; | |
1619 | ||
1620 | list_splice_init(&plug->mq_list, &list); | |
1621 | ||
1622 | list_sort(NULL, &list, plug_ctx_cmp); | |
1623 | ||
1624 | this_q = NULL; | |
1625 | this_ctx = NULL; | |
1626 | depth = 0; | |
1627 | ||
1628 | while (!list_empty(&list)) { | |
1629 | rq = list_entry_rq(list.next); | |
1630 | list_del_init(&rq->queuelist); | |
1631 | BUG_ON(!rq->q); | |
1632 | if (rq->mq_ctx != this_ctx) { | |
1633 | if (this_ctx) { | |
1634 | trace_block_unplug(this_q, depth, !from_schedule); | |
1635 | blk_mq_sched_insert_requests(this_q, this_ctx, | |
1636 | &ctx_list, | |
1637 | from_schedule); | |
1638 | } | |
1639 | ||
1640 | this_ctx = rq->mq_ctx; | |
1641 | this_q = rq->q; | |
1642 | depth = 0; | |
1643 | } | |
1644 | ||
1645 | depth++; | |
1646 | list_add_tail(&rq->queuelist, &ctx_list); | |
1647 | } | |
1648 | ||
1649 | /* | |
1650 | * If 'this_ctx' is set, we know we have entries to complete | |
1651 | * on 'ctx_list'. Do those. | |
1652 | */ | |
1653 | if (this_ctx) { | |
1654 | trace_block_unplug(this_q, depth, !from_schedule); | |
1655 | blk_mq_sched_insert_requests(this_q, this_ctx, &ctx_list, | |
1656 | from_schedule); | |
1657 | } | |
1658 | } | |
1659 | ||
1660 | static void blk_mq_bio_to_request(struct request *rq, struct bio *bio) | |
1661 | { | |
1662 | blk_init_request_from_bio(rq, bio); | |
1663 | ||
1664 | blk_rq_set_rl(rq, blk_get_rl(rq->q, bio)); | |
1665 | ||
1666 | blk_account_io_start(rq, true); | |
1667 | } | |
1668 | ||
1669 | static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq) | |
1670 | { | |
1671 | if (rq->tag != -1) | |
1672 | return blk_tag_to_qc_t(rq->tag, hctx->queue_num, false); | |
1673 | ||
1674 | return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true); | |
1675 | } | |
1676 | ||
1677 | static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, | |
1678 | struct request *rq, | |
1679 | blk_qc_t *cookie) | |
1680 | { | |
1681 | struct request_queue *q = rq->q; | |
1682 | struct blk_mq_queue_data bd = { | |
1683 | .rq = rq, | |
1684 | .last = true, | |
1685 | }; | |
1686 | blk_qc_t new_cookie; | |
1687 | blk_status_t ret; | |
1688 | ||
1689 | new_cookie = request_to_qc_t(hctx, rq); | |
1690 | ||
1691 | /* | |
1692 | * For OK queue, we are done. For error, caller may kill it. | |
1693 | * Any other error (busy), just add it to our list as we | |
1694 | * previously would have done. | |
1695 | */ | |
1696 | ret = q->mq_ops->queue_rq(hctx, &bd); | |
1697 | switch (ret) { | |
1698 | case BLK_STS_OK: | |
1699 | blk_mq_update_dispatch_busy(hctx, false); | |
1700 | *cookie = new_cookie; | |
1701 | break; | |
1702 | case BLK_STS_RESOURCE: | |
1703 | case BLK_STS_DEV_RESOURCE: | |
1704 | blk_mq_update_dispatch_busy(hctx, true); | |
1705 | __blk_mq_requeue_request(rq); | |
1706 | break; | |
1707 | default: | |
1708 | blk_mq_update_dispatch_busy(hctx, false); | |
1709 | *cookie = BLK_QC_T_NONE; | |
1710 | break; | |
1711 | } | |
1712 | ||
1713 | return ret; | |
1714 | } | |
1715 | ||
1716 | static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, | |
1717 | struct request *rq, | |
1718 | blk_qc_t *cookie, | |
1719 | bool bypass_insert) | |
1720 | { | |
1721 | struct request_queue *q = rq->q; | |
1722 | bool run_queue = true; | |
1723 | ||
1724 | /* | |
1725 | * RCU or SRCU read lock is needed before checking quiesced flag. | |
1726 | * | |
1727 | * When queue is stopped or quiesced, ignore 'bypass_insert' from | |
1728 | * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller, | |
1729 | * and avoid driver to try to dispatch again. | |
1730 | */ | |
1731 | if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { | |
1732 | run_queue = false; | |
1733 | bypass_insert = false; | |
1734 | goto insert; | |
1735 | } | |
1736 | ||
1737 | if (q->elevator && !bypass_insert) | |
1738 | goto insert; | |
1739 | ||
1740 | if (!blk_mq_get_dispatch_budget(hctx)) | |
1741 | goto insert; | |
1742 | ||
1743 | if (!blk_mq_get_driver_tag(rq)) { | |
1744 | blk_mq_put_dispatch_budget(hctx); | |
1745 | goto insert; | |
1746 | } | |
1747 | ||
1748 | return __blk_mq_issue_directly(hctx, rq, cookie); | |
1749 | insert: | |
1750 | if (bypass_insert) | |
1751 | return BLK_STS_RESOURCE; | |
1752 | ||
1753 | blk_mq_sched_insert_request(rq, false, run_queue, false); | |
1754 | return BLK_STS_OK; | |
1755 | } | |
1756 | ||
1757 | static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, | |
1758 | struct request *rq, blk_qc_t *cookie) | |
1759 | { | |
1760 | blk_status_t ret; | |
1761 | int srcu_idx; | |
1762 | ||
1763 | might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); | |
1764 | ||
1765 | hctx_lock(hctx, &srcu_idx); | |
1766 | ||
1767 | ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false); | |
1768 | if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) | |
1769 | blk_mq_sched_insert_request(rq, false, true, false); | |
1770 | else if (ret != BLK_STS_OK) | |
1771 | blk_mq_end_request(rq, ret); | |
1772 | ||
1773 | hctx_unlock(hctx, srcu_idx); | |
1774 | } | |
1775 | ||
1776 | blk_status_t blk_mq_request_issue_directly(struct request *rq) | |
1777 | { | |
1778 | blk_status_t ret; | |
1779 | int srcu_idx; | |
1780 | blk_qc_t unused_cookie; | |
1781 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
1782 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(rq->q, ctx->cpu); | |
1783 | ||
1784 | hctx_lock(hctx, &srcu_idx); | |
1785 | ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true); | |
1786 | hctx_unlock(hctx, srcu_idx); | |
1787 | ||
1788 | return ret; | |
1789 | } | |
1790 | ||
1791 | void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, | |
1792 | struct list_head *list) | |
1793 | { | |
1794 | while (!list_empty(list)) { | |
1795 | blk_status_t ret; | |
1796 | struct request *rq = list_first_entry(list, struct request, | |
1797 | queuelist); | |
1798 | ||
1799 | list_del_init(&rq->queuelist); | |
1800 | ret = blk_mq_request_issue_directly(rq); | |
1801 | if (ret != BLK_STS_OK) { | |
1802 | if (ret == BLK_STS_RESOURCE || | |
1803 | ret == BLK_STS_DEV_RESOURCE) { | |
1804 | list_add(&rq->queuelist, list); | |
1805 | break; | |
1806 | } | |
1807 | blk_mq_end_request(rq, ret); | |
1808 | } | |
1809 | } | |
1810 | } | |
1811 | ||
1812 | static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) | |
1813 | { | |
1814 | const int is_sync = op_is_sync(bio->bi_opf); | |
1815 | const int is_flush_fua = op_is_flush(bio->bi_opf); | |
1816 | struct blk_mq_alloc_data data = { .flags = 0 }; | |
1817 | struct request *rq; | |
1818 | unsigned int request_count = 0; | |
1819 | struct blk_plug *plug; | |
1820 | struct request *same_queue_rq = NULL; | |
1821 | blk_qc_t cookie; | |
1822 | ||
1823 | blk_queue_bounce(q, &bio); | |
1824 | ||
1825 | blk_queue_split(q, &bio); | |
1826 | ||
1827 | if (!bio_integrity_prep(bio)) | |
1828 | return BLK_QC_T_NONE; | |
1829 | ||
1830 | if (!is_flush_fua && !blk_queue_nomerges(q) && | |
1831 | blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq)) | |
1832 | return BLK_QC_T_NONE; | |
1833 | ||
1834 | if (blk_mq_sched_bio_merge(q, bio)) | |
1835 | return BLK_QC_T_NONE; | |
1836 | ||
1837 | rq_qos_throttle(q, bio, NULL); | |
1838 | ||
1839 | trace_block_getrq(q, bio, bio->bi_opf); | |
1840 | ||
1841 | rq = blk_mq_get_request(q, bio, bio->bi_opf, &data); | |
1842 | if (unlikely(!rq)) { | |
1843 | rq_qos_cleanup(q, bio); | |
1844 | if (bio->bi_opf & REQ_NOWAIT) | |
1845 | bio_wouldblock_error(bio); | |
1846 | return BLK_QC_T_NONE; | |
1847 | } | |
1848 | ||
1849 | rq_qos_track(q, rq, bio); | |
1850 | ||
1851 | cookie = request_to_qc_t(data.hctx, rq); | |
1852 | ||
1853 | plug = current->plug; | |
1854 | if (unlikely(is_flush_fua)) { | |
1855 | blk_mq_put_ctx(data.ctx); | |
1856 | blk_mq_bio_to_request(rq, bio); | |
1857 | ||
1858 | /* bypass scheduler for flush rq */ | |
1859 | blk_insert_flush(rq); | |
1860 | blk_mq_run_hw_queue(data.hctx, true); | |
1861 | } else if (plug && q->nr_hw_queues == 1) { | |
1862 | struct request *last = NULL; | |
1863 | ||
1864 | blk_mq_put_ctx(data.ctx); | |
1865 | blk_mq_bio_to_request(rq, bio); | |
1866 | ||
1867 | /* | |
1868 | * @request_count may become stale because of schedule | |
1869 | * out, so check the list again. | |
1870 | */ | |
1871 | if (list_empty(&plug->mq_list)) | |
1872 | request_count = 0; | |
1873 | else if (blk_queue_nomerges(q)) | |
1874 | request_count = blk_plug_queued_count(q); | |
1875 | ||
1876 | if (!request_count) | |
1877 | trace_block_plug(q); | |
1878 | else | |
1879 | last = list_entry_rq(plug->mq_list.prev); | |
1880 | ||
1881 | if (request_count >= BLK_MAX_REQUEST_COUNT || (last && | |
1882 | blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { | |
1883 | blk_flush_plug_list(plug, false); | |
1884 | trace_block_plug(q); | |
1885 | } | |
1886 | ||
1887 | list_add_tail(&rq->queuelist, &plug->mq_list); | |
1888 | } else if (plug && !blk_queue_nomerges(q)) { | |
1889 | blk_mq_bio_to_request(rq, bio); | |
1890 | ||
1891 | /* | |
1892 | * We do limited plugging. If the bio can be merged, do that. | |
1893 | * Otherwise the existing request in the plug list will be | |
1894 | * issued. So the plug list will have one request at most | |
1895 | * The plug list might get flushed before this. If that happens, | |
1896 | * the plug list is empty, and same_queue_rq is invalid. | |
1897 | */ | |
1898 | if (list_empty(&plug->mq_list)) | |
1899 | same_queue_rq = NULL; | |
1900 | if (same_queue_rq) | |
1901 | list_del_init(&same_queue_rq->queuelist); | |
1902 | list_add_tail(&rq->queuelist, &plug->mq_list); | |
1903 | ||
1904 | blk_mq_put_ctx(data.ctx); | |
1905 | ||
1906 | if (same_queue_rq) { | |
1907 | data.hctx = blk_mq_map_queue(q, | |
1908 | same_queue_rq->mq_ctx->cpu); | |
1909 | blk_mq_try_issue_directly(data.hctx, same_queue_rq, | |
1910 | &cookie); | |
1911 | } | |
1912 | } else if ((q->nr_hw_queues > 1 && is_sync) || (!q->elevator && | |
1913 | !data.hctx->dispatch_busy)) { | |
1914 | blk_mq_put_ctx(data.ctx); | |
1915 | blk_mq_bio_to_request(rq, bio); | |
1916 | blk_mq_try_issue_directly(data.hctx, rq, &cookie); | |
1917 | } else { | |
1918 | blk_mq_put_ctx(data.ctx); | |
1919 | blk_mq_bio_to_request(rq, bio); | |
1920 | blk_mq_sched_insert_request(rq, false, true, true); | |
1921 | } | |
1922 | ||
1923 | return cookie; | |
1924 | } | |
1925 | ||
1926 | void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, | |
1927 | unsigned int hctx_idx) | |
1928 | { | |
1929 | struct page *page; | |
1930 | ||
1931 | if (tags->rqs && set->ops->exit_request) { | |
1932 | int i; | |
1933 | ||
1934 | for (i = 0; i < tags->nr_tags; i++) { | |
1935 | struct request *rq = tags->static_rqs[i]; | |
1936 | ||
1937 | if (!rq) | |
1938 | continue; | |
1939 | set->ops->exit_request(set, rq, hctx_idx); | |
1940 | tags->static_rqs[i] = NULL; | |
1941 | } | |
1942 | } | |
1943 | ||
1944 | while (!list_empty(&tags->page_list)) { | |
1945 | page = list_first_entry(&tags->page_list, struct page, lru); | |
1946 | list_del_init(&page->lru); | |
1947 | /* | |
1948 | * Remove kmemleak object previously allocated in | |
1949 | * blk_mq_init_rq_map(). | |
1950 | */ | |
1951 | kmemleak_free(page_address(page)); | |
1952 | __free_pages(page, page->private); | |
1953 | } | |
1954 | } | |
1955 | ||
1956 | void blk_mq_free_rq_map(struct blk_mq_tags *tags) | |
1957 | { | |
1958 | kfree(tags->rqs); | |
1959 | tags->rqs = NULL; | |
1960 | kfree(tags->static_rqs); | |
1961 | tags->static_rqs = NULL; | |
1962 | ||
1963 | blk_mq_free_tags(tags); | |
1964 | } | |
1965 | ||
1966 | struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, | |
1967 | unsigned int hctx_idx, | |
1968 | unsigned int nr_tags, | |
1969 | unsigned int reserved_tags) | |
1970 | { | |
1971 | struct blk_mq_tags *tags; | |
1972 | int node; | |
1973 | ||
1974 | node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx); | |
1975 | if (node == NUMA_NO_NODE) | |
1976 | node = set->numa_node; | |
1977 | ||
1978 | tags = blk_mq_init_tags(nr_tags, reserved_tags, node, | |
1979 | BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags)); | |
1980 | if (!tags) | |
1981 | return NULL; | |
1982 | ||
1983 | tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *), | |
1984 | GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, | |
1985 | node); | |
1986 | if (!tags->rqs) { | |
1987 | blk_mq_free_tags(tags); | |
1988 | return NULL; | |
1989 | } | |
1990 | ||
1991 | tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *), | |
1992 | GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, | |
1993 | node); | |
1994 | if (!tags->static_rqs) { | |
1995 | kfree(tags->rqs); | |
1996 | blk_mq_free_tags(tags); | |
1997 | return NULL; | |
1998 | } | |
1999 | ||
2000 | return tags; | |
2001 | } | |
2002 | ||
2003 | static size_t order_to_size(unsigned int order) | |
2004 | { | |
2005 | return (size_t)PAGE_SIZE << order; | |
2006 | } | |
2007 | ||
2008 | static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, | |
2009 | unsigned int hctx_idx, int node) | |
2010 | { | |
2011 | int ret; | |
2012 | ||
2013 | if (set->ops->init_request) { | |
2014 | ret = set->ops->init_request(set, rq, hctx_idx, node); | |
2015 | if (ret) | |
2016 | return ret; | |
2017 | } | |
2018 | ||
2019 | WRITE_ONCE(rq->state, MQ_RQ_IDLE); | |
2020 | return 0; | |
2021 | } | |
2022 | ||
2023 | int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, | |
2024 | unsigned int hctx_idx, unsigned int depth) | |
2025 | { | |
2026 | unsigned int i, j, entries_per_page, max_order = 4; | |
2027 | size_t rq_size, left; | |
2028 | int node; | |
2029 | ||
2030 | node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx); | |
2031 | if (node == NUMA_NO_NODE) | |
2032 | node = set->numa_node; | |
2033 | ||
2034 | INIT_LIST_HEAD(&tags->page_list); | |
2035 | ||
2036 | /* | |
2037 | * rq_size is the size of the request plus driver payload, rounded | |
2038 | * to the cacheline size | |
2039 | */ | |
2040 | rq_size = round_up(sizeof(struct request) + set->cmd_size, | |
2041 | cache_line_size()); | |
2042 | left = rq_size * depth; | |
2043 | ||
2044 | for (i = 0; i < depth; ) { | |
2045 | int this_order = max_order; | |
2046 | struct page *page; | |
2047 | int to_do; | |
2048 | void *p; | |
2049 | ||
2050 | while (this_order && left < order_to_size(this_order - 1)) | |
2051 | this_order--; | |
2052 | ||
2053 | do { | |
2054 | page = alloc_pages_node(node, | |
2055 | GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO, | |
2056 | this_order); | |
2057 | if (page) | |
2058 | break; | |
2059 | if (!this_order--) | |
2060 | break; | |
2061 | if (order_to_size(this_order) < rq_size) | |
2062 | break; | |
2063 | } while (1); | |
2064 | ||
2065 | if (!page) | |
2066 | goto fail; | |
2067 | ||
2068 | page->private = this_order; | |
2069 | list_add_tail(&page->lru, &tags->page_list); | |
2070 | ||
2071 | p = page_address(page); | |
2072 | /* | |
2073 | * Allow kmemleak to scan these pages as they contain pointers | |
2074 | * to additional allocations like via ops->init_request(). | |
2075 | */ | |
2076 | kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO); | |
2077 | entries_per_page = order_to_size(this_order) / rq_size; | |
2078 | to_do = min(entries_per_page, depth - i); | |
2079 | left -= to_do * rq_size; | |
2080 | for (j = 0; j < to_do; j++) { | |
2081 | struct request *rq = p; | |
2082 | ||
2083 | tags->static_rqs[i] = rq; | |
2084 | if (blk_mq_init_request(set, rq, hctx_idx, node)) { | |
2085 | tags->static_rqs[i] = NULL; | |
2086 | goto fail; | |
2087 | } | |
2088 | ||
2089 | p += rq_size; | |
2090 | i++; | |
2091 | } | |
2092 | } | |
2093 | return 0; | |
2094 | ||
2095 | fail: | |
2096 | blk_mq_free_rqs(set, tags, hctx_idx); | |
2097 | return -ENOMEM; | |
2098 | } | |
2099 | ||
2100 | /* | |
2101 | * 'cpu' is going away. splice any existing rq_list entries from this | |
2102 | * software queue to the hw queue dispatch list, and ensure that it | |
2103 | * gets run. | |
2104 | */ | |
2105 | static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node) | |
2106 | { | |
2107 | struct blk_mq_hw_ctx *hctx; | |
2108 | struct blk_mq_ctx *ctx; | |
2109 | LIST_HEAD(tmp); | |
2110 | ||
2111 | hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead); | |
2112 | ctx = __blk_mq_get_ctx(hctx->queue, cpu); | |
2113 | ||
2114 | spin_lock(&ctx->lock); | |
2115 | if (!list_empty(&ctx->rq_list)) { | |
2116 | list_splice_init(&ctx->rq_list, &tmp); | |
2117 | blk_mq_hctx_clear_pending(hctx, ctx); | |
2118 | } | |
2119 | spin_unlock(&ctx->lock); | |
2120 | ||
2121 | if (list_empty(&tmp)) | |
2122 | return 0; | |
2123 | ||
2124 | spin_lock(&hctx->lock); | |
2125 | list_splice_tail_init(&tmp, &hctx->dispatch); | |
2126 | spin_unlock(&hctx->lock); | |
2127 | ||
2128 | blk_mq_run_hw_queue(hctx, true); | |
2129 | return 0; | |
2130 | } | |
2131 | ||
2132 | static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx) | |
2133 | { | |
2134 | cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD, | |
2135 | &hctx->cpuhp_dead); | |
2136 | } | |
2137 | ||
2138 | /* hctx->ctxs will be freed in queue's release handler */ | |
2139 | static void blk_mq_exit_hctx(struct request_queue *q, | |
2140 | struct blk_mq_tag_set *set, | |
2141 | struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) | |
2142 | { | |
2143 | blk_mq_debugfs_unregister_hctx(hctx); | |
2144 | ||
2145 | if (blk_mq_hw_queue_mapped(hctx)) | |
2146 | blk_mq_tag_idle(hctx); | |
2147 | ||
2148 | if (set->ops->exit_request) | |
2149 | set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx); | |
2150 | ||
2151 | if (set->ops->exit_hctx) | |
2152 | set->ops->exit_hctx(hctx, hctx_idx); | |
2153 | ||
2154 | if (hctx->flags & BLK_MQ_F_BLOCKING) | |
2155 | cleanup_srcu_struct(hctx->srcu); | |
2156 | ||
2157 | blk_mq_remove_cpuhp(hctx); | |
2158 | blk_free_flush_queue(hctx->fq); | |
2159 | sbitmap_free(&hctx->ctx_map); | |
2160 | } | |
2161 | ||
2162 | static void blk_mq_exit_hw_queues(struct request_queue *q, | |
2163 | struct blk_mq_tag_set *set, int nr_queue) | |
2164 | { | |
2165 | struct blk_mq_hw_ctx *hctx; | |
2166 | unsigned int i; | |
2167 | ||
2168 | queue_for_each_hw_ctx(q, hctx, i) { | |
2169 | if (i == nr_queue) | |
2170 | break; | |
2171 | blk_mq_exit_hctx(q, set, hctx, i); | |
2172 | } | |
2173 | } | |
2174 | ||
2175 | static int blk_mq_init_hctx(struct request_queue *q, | |
2176 | struct blk_mq_tag_set *set, | |
2177 | struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) | |
2178 | { | |
2179 | int node; | |
2180 | ||
2181 | node = hctx->numa_node; | |
2182 | if (node == NUMA_NO_NODE) | |
2183 | node = hctx->numa_node = set->numa_node; | |
2184 | ||
2185 | INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); | |
2186 | spin_lock_init(&hctx->lock); | |
2187 | INIT_LIST_HEAD(&hctx->dispatch); | |
2188 | hctx->queue = q; | |
2189 | hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED; | |
2190 | ||
2191 | cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead); | |
2192 | ||
2193 | hctx->tags = set->tags[hctx_idx]; | |
2194 | ||
2195 | /* | |
2196 | * Allocate space for all possible cpus to avoid allocation at | |
2197 | * runtime | |
2198 | */ | |
2199 | hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *), | |
2200 | GFP_KERNEL, node); | |
2201 | if (!hctx->ctxs) | |
2202 | goto unregister_cpu_notifier; | |
2203 | ||
2204 | if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), GFP_KERNEL, | |
2205 | node)) | |
2206 | goto free_ctxs; | |
2207 | ||
2208 | hctx->nr_ctx = 0; | |
2209 | ||
2210 | spin_lock_init(&hctx->dispatch_wait_lock); | |
2211 | init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake); | |
2212 | INIT_LIST_HEAD(&hctx->dispatch_wait.entry); | |
2213 | ||
2214 | if (set->ops->init_hctx && | |
2215 | set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) | |
2216 | goto free_bitmap; | |
2217 | ||
2218 | hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size); | |
2219 | if (!hctx->fq) | |
2220 | goto exit_hctx; | |
2221 | ||
2222 | if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx, node)) | |
2223 | goto free_fq; | |
2224 | ||
2225 | if (hctx->flags & BLK_MQ_F_BLOCKING) | |
2226 | init_srcu_struct(hctx->srcu); | |
2227 | ||
2228 | blk_mq_debugfs_register_hctx(q, hctx); | |
2229 | ||
2230 | return 0; | |
2231 | ||
2232 | free_fq: | |
2233 | kfree(hctx->fq); | |
2234 | exit_hctx: | |
2235 | if (set->ops->exit_hctx) | |
2236 | set->ops->exit_hctx(hctx, hctx_idx); | |
2237 | free_bitmap: | |
2238 | sbitmap_free(&hctx->ctx_map); | |
2239 | free_ctxs: | |
2240 | kfree(hctx->ctxs); | |
2241 | unregister_cpu_notifier: | |
2242 | blk_mq_remove_cpuhp(hctx); | |
2243 | return -1; | |
2244 | } | |
2245 | ||
2246 | static void blk_mq_init_cpu_queues(struct request_queue *q, | |
2247 | unsigned int nr_hw_queues) | |
2248 | { | |
2249 | unsigned int i; | |
2250 | ||
2251 | for_each_possible_cpu(i) { | |
2252 | struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); | |
2253 | struct blk_mq_hw_ctx *hctx; | |
2254 | ||
2255 | __ctx->cpu = i; | |
2256 | spin_lock_init(&__ctx->lock); | |
2257 | INIT_LIST_HEAD(&__ctx->rq_list); | |
2258 | __ctx->queue = q; | |
2259 | ||
2260 | /* | |
2261 | * Set local node, IFF we have more than one hw queue. If | |
2262 | * not, we remain on the home node of the device | |
2263 | */ | |
2264 | hctx = blk_mq_map_queue(q, i); | |
2265 | if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) | |
2266 | hctx->numa_node = local_memory_node(cpu_to_node(i)); | |
2267 | } | |
2268 | } | |
2269 | ||
2270 | static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx) | |
2271 | { | |
2272 | int ret = 0; | |
2273 | ||
2274 | set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx, | |
2275 | set->queue_depth, set->reserved_tags); | |
2276 | if (!set->tags[hctx_idx]) | |
2277 | return false; | |
2278 | ||
2279 | ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx, | |
2280 | set->queue_depth); | |
2281 | if (!ret) | |
2282 | return true; | |
2283 | ||
2284 | blk_mq_free_rq_map(set->tags[hctx_idx]); | |
2285 | set->tags[hctx_idx] = NULL; | |
2286 | return false; | |
2287 | } | |
2288 | ||
2289 | static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set, | |
2290 | unsigned int hctx_idx) | |
2291 | { | |
2292 | if (set->tags[hctx_idx]) { | |
2293 | blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx); | |
2294 | blk_mq_free_rq_map(set->tags[hctx_idx]); | |
2295 | set->tags[hctx_idx] = NULL; | |
2296 | } | |
2297 | } | |
2298 | ||
2299 | static void blk_mq_map_swqueue(struct request_queue *q) | |
2300 | { | |
2301 | unsigned int i, hctx_idx; | |
2302 | struct blk_mq_hw_ctx *hctx; | |
2303 | struct blk_mq_ctx *ctx; | |
2304 | struct blk_mq_tag_set *set = q->tag_set; | |
2305 | ||
2306 | /* | |
2307 | * Avoid others reading imcomplete hctx->cpumask through sysfs | |
2308 | */ | |
2309 | mutex_lock(&q->sysfs_lock); | |
2310 | ||
2311 | queue_for_each_hw_ctx(q, hctx, i) { | |
2312 | cpumask_clear(hctx->cpumask); | |
2313 | hctx->nr_ctx = 0; | |
2314 | hctx->dispatch_from = NULL; | |
2315 | } | |
2316 | ||
2317 | /* | |
2318 | * Map software to hardware queues. | |
2319 | * | |
2320 | * If the cpu isn't present, the cpu is mapped to first hctx. | |
2321 | */ | |
2322 | for_each_possible_cpu(i) { | |
2323 | hctx_idx = q->mq_map[i]; | |
2324 | /* unmapped hw queue can be remapped after CPU topo changed */ | |
2325 | if (!set->tags[hctx_idx] && | |
2326 | !__blk_mq_alloc_rq_map(set, hctx_idx)) { | |
2327 | /* | |
2328 | * If tags initialization fail for some hctx, | |
2329 | * that hctx won't be brought online. In this | |
2330 | * case, remap the current ctx to hctx[0] which | |
2331 | * is guaranteed to always have tags allocated | |
2332 | */ | |
2333 | q->mq_map[i] = 0; | |
2334 | } | |
2335 | ||
2336 | ctx = per_cpu_ptr(q->queue_ctx, i); | |
2337 | hctx = blk_mq_map_queue(q, i); | |
2338 | ||
2339 | cpumask_set_cpu(i, hctx->cpumask); | |
2340 | ctx->index_hw = hctx->nr_ctx; | |
2341 | hctx->ctxs[hctx->nr_ctx++] = ctx; | |
2342 | } | |
2343 | ||
2344 | mutex_unlock(&q->sysfs_lock); | |
2345 | ||
2346 | queue_for_each_hw_ctx(q, hctx, i) { | |
2347 | /* | |
2348 | * If no software queues are mapped to this hardware queue, | |
2349 | * disable it and free the request entries. | |
2350 | */ | |
2351 | if (!hctx->nr_ctx) { | |
2352 | /* Never unmap queue 0. We need it as a | |
2353 | * fallback in case of a new remap fails | |
2354 | * allocation | |
2355 | */ | |
2356 | if (i && set->tags[i]) | |
2357 | blk_mq_free_map_and_requests(set, i); | |
2358 | ||
2359 | hctx->tags = NULL; | |
2360 | continue; | |
2361 | } | |
2362 | ||
2363 | hctx->tags = set->tags[i]; | |
2364 | WARN_ON(!hctx->tags); | |
2365 | ||
2366 | /* | |
2367 | * Set the map size to the number of mapped software queues. | |
2368 | * This is more accurate and more efficient than looping | |
2369 | * over all possibly mapped software queues. | |
2370 | */ | |
2371 | sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx); | |
2372 | ||
2373 | /* | |
2374 | * Initialize batch roundrobin counts | |
2375 | */ | |
2376 | hctx->next_cpu = blk_mq_first_mapped_cpu(hctx); | |
2377 | hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; | |
2378 | } | |
2379 | } | |
2380 | ||
2381 | /* | |
2382 | * Caller needs to ensure that we're either frozen/quiesced, or that | |
2383 | * the queue isn't live yet. | |
2384 | */ | |
2385 | static void queue_set_hctx_shared(struct request_queue *q, bool shared) | |
2386 | { | |
2387 | struct blk_mq_hw_ctx *hctx; | |
2388 | int i; | |
2389 | ||
2390 | queue_for_each_hw_ctx(q, hctx, i) { | |
2391 | if (shared) | |
2392 | hctx->flags |= BLK_MQ_F_TAG_SHARED; | |
2393 | else | |
2394 | hctx->flags &= ~BLK_MQ_F_TAG_SHARED; | |
2395 | } | |
2396 | } | |
2397 | ||
2398 | static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set, | |
2399 | bool shared) | |
2400 | { | |
2401 | struct request_queue *q; | |
2402 | ||
2403 | lockdep_assert_held(&set->tag_list_lock); | |
2404 | ||
2405 | list_for_each_entry(q, &set->tag_list, tag_set_list) { | |
2406 | blk_mq_freeze_queue(q); | |
2407 | queue_set_hctx_shared(q, shared); | |
2408 | blk_mq_unfreeze_queue(q); | |
2409 | } | |
2410 | } | |
2411 | ||
2412 | static void blk_mq_del_queue_tag_set(struct request_queue *q) | |
2413 | { | |
2414 | struct blk_mq_tag_set *set = q->tag_set; | |
2415 | ||
2416 | mutex_lock(&set->tag_list_lock); | |
2417 | list_del_rcu(&q->tag_set_list); | |
2418 | if (list_is_singular(&set->tag_list)) { | |
2419 | /* just transitioned to unshared */ | |
2420 | set->flags &= ~BLK_MQ_F_TAG_SHARED; | |
2421 | /* update existing queue */ | |
2422 | blk_mq_update_tag_set_depth(set, false); | |
2423 | } | |
2424 | mutex_unlock(&set->tag_list_lock); | |
2425 | INIT_LIST_HEAD(&q->tag_set_list); | |
2426 | } | |
2427 | ||
2428 | static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, | |
2429 | struct request_queue *q) | |
2430 | { | |
2431 | q->tag_set = set; | |
2432 | ||
2433 | mutex_lock(&set->tag_list_lock); | |
2434 | ||
2435 | /* | |
2436 | * Check to see if we're transitioning to shared (from 1 to 2 queues). | |
2437 | */ | |
2438 | if (!list_empty(&set->tag_list) && | |
2439 | !(set->flags & BLK_MQ_F_TAG_SHARED)) { | |
2440 | set->flags |= BLK_MQ_F_TAG_SHARED; | |
2441 | /* update existing queue */ | |
2442 | blk_mq_update_tag_set_depth(set, true); | |
2443 | } | |
2444 | if (set->flags & BLK_MQ_F_TAG_SHARED) | |
2445 | queue_set_hctx_shared(q, true); | |
2446 | list_add_tail_rcu(&q->tag_set_list, &set->tag_list); | |
2447 | ||
2448 | mutex_unlock(&set->tag_list_lock); | |
2449 | } | |
2450 | ||
2451 | /* | |
2452 | * It is the actual release handler for mq, but we do it from | |
2453 | * request queue's release handler for avoiding use-after-free | |
2454 | * and headache because q->mq_kobj shouldn't have been introduced, | |
2455 | * but we can't group ctx/kctx kobj without it. | |
2456 | */ | |
2457 | void blk_mq_release(struct request_queue *q) | |
2458 | { | |
2459 | struct blk_mq_hw_ctx *hctx; | |
2460 | unsigned int i; | |
2461 | ||
2462 | /* hctx kobj stays in hctx */ | |
2463 | queue_for_each_hw_ctx(q, hctx, i) { | |
2464 | if (!hctx) | |
2465 | continue; | |
2466 | kobject_put(&hctx->kobj); | |
2467 | } | |
2468 | ||
2469 | q->mq_map = NULL; | |
2470 | ||
2471 | kfree(q->queue_hw_ctx); | |
2472 | ||
2473 | /* | |
2474 | * release .mq_kobj and sw queue's kobject now because | |
2475 | * both share lifetime with request queue. | |
2476 | */ | |
2477 | blk_mq_sysfs_deinit(q); | |
2478 | ||
2479 | free_percpu(q->queue_ctx); | |
2480 | } | |
2481 | ||
2482 | struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) | |
2483 | { | |
2484 | struct request_queue *uninit_q, *q; | |
2485 | ||
2486 | uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node, NULL); | |
2487 | if (!uninit_q) | |
2488 | return ERR_PTR(-ENOMEM); | |
2489 | ||
2490 | q = blk_mq_init_allocated_queue(set, uninit_q); | |
2491 | if (IS_ERR(q)) | |
2492 | blk_cleanup_queue(uninit_q); | |
2493 | ||
2494 | return q; | |
2495 | } | |
2496 | EXPORT_SYMBOL(blk_mq_init_queue); | |
2497 | ||
2498 | static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set) | |
2499 | { | |
2500 | int hw_ctx_size = sizeof(struct blk_mq_hw_ctx); | |
2501 | ||
2502 | BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx, srcu), | |
2503 | __alignof__(struct blk_mq_hw_ctx)) != | |
2504 | sizeof(struct blk_mq_hw_ctx)); | |
2505 | ||
2506 | if (tag_set->flags & BLK_MQ_F_BLOCKING) | |
2507 | hw_ctx_size += sizeof(struct srcu_struct); | |
2508 | ||
2509 | return hw_ctx_size; | |
2510 | } | |
2511 | ||
2512 | static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, | |
2513 | struct request_queue *q) | |
2514 | { | |
2515 | int i, j; | |
2516 | struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx; | |
2517 | ||
2518 | blk_mq_sysfs_unregister(q); | |
2519 | ||
2520 | /* protect against switching io scheduler */ | |
2521 | mutex_lock(&q->sysfs_lock); | |
2522 | for (i = 0; i < set->nr_hw_queues; i++) { | |
2523 | int node; | |
2524 | ||
2525 | if (hctxs[i]) | |
2526 | continue; | |
2527 | ||
2528 | node = blk_mq_hw_queue_to_node(q->mq_map, i); | |
2529 | hctxs[i] = kzalloc_node(blk_mq_hw_ctx_size(set), | |
2530 | GFP_KERNEL, node); | |
2531 | if (!hctxs[i]) | |
2532 | break; | |
2533 | ||
2534 | if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL, | |
2535 | node)) { | |
2536 | kfree(hctxs[i]); | |
2537 | hctxs[i] = NULL; | |
2538 | break; | |
2539 | } | |
2540 | ||
2541 | atomic_set(&hctxs[i]->nr_active, 0); | |
2542 | hctxs[i]->numa_node = node; | |
2543 | hctxs[i]->queue_num = i; | |
2544 | ||
2545 | if (blk_mq_init_hctx(q, set, hctxs[i], i)) { | |
2546 | free_cpumask_var(hctxs[i]->cpumask); | |
2547 | kfree(hctxs[i]); | |
2548 | hctxs[i] = NULL; | |
2549 | break; | |
2550 | } | |
2551 | blk_mq_hctx_kobj_init(hctxs[i]); | |
2552 | } | |
2553 | for (j = i; j < q->nr_hw_queues; j++) { | |
2554 | struct blk_mq_hw_ctx *hctx = hctxs[j]; | |
2555 | ||
2556 | if (hctx) { | |
2557 | if (hctx->tags) | |
2558 | blk_mq_free_map_and_requests(set, j); | |
2559 | blk_mq_exit_hctx(q, set, hctx, j); | |
2560 | kobject_put(&hctx->kobj); | |
2561 | hctxs[j] = NULL; | |
2562 | ||
2563 | } | |
2564 | } | |
2565 | q->nr_hw_queues = i; | |
2566 | mutex_unlock(&q->sysfs_lock); | |
2567 | blk_mq_sysfs_register(q); | |
2568 | } | |
2569 | ||
2570 | struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, | |
2571 | struct request_queue *q) | |
2572 | { | |
2573 | /* mark the queue as mq asap */ | |
2574 | q->mq_ops = set->ops; | |
2575 | ||
2576 | q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn, | |
2577 | blk_mq_poll_stats_bkt, | |
2578 | BLK_MQ_POLL_STATS_BKTS, q); | |
2579 | if (!q->poll_cb) | |
2580 | goto err_exit; | |
2581 | ||
2582 | q->queue_ctx = alloc_percpu(struct blk_mq_ctx); | |
2583 | if (!q->queue_ctx) | |
2584 | goto err_exit; | |
2585 | ||
2586 | /* init q->mq_kobj and sw queues' kobjects */ | |
2587 | blk_mq_sysfs_init(q); | |
2588 | ||
2589 | q->queue_hw_ctx = kcalloc_node(nr_cpu_ids, sizeof(*(q->queue_hw_ctx)), | |
2590 | GFP_KERNEL, set->numa_node); | |
2591 | if (!q->queue_hw_ctx) | |
2592 | goto err_percpu; | |
2593 | ||
2594 | q->mq_map = set->mq_map; | |
2595 | ||
2596 | blk_mq_realloc_hw_ctxs(set, q); | |
2597 | if (!q->nr_hw_queues) | |
2598 | goto err_hctxs; | |
2599 | ||
2600 | INIT_WORK(&q->timeout_work, blk_mq_timeout_work); | |
2601 | blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); | |
2602 | ||
2603 | q->nr_queues = nr_cpu_ids; | |
2604 | ||
2605 | q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; | |
2606 | ||
2607 | if (!(set->flags & BLK_MQ_F_SG_MERGE)) | |
2608 | queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q); | |
2609 | ||
2610 | q->sg_reserved_size = INT_MAX; | |
2611 | ||
2612 | INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work); | |
2613 | INIT_LIST_HEAD(&q->requeue_list); | |
2614 | spin_lock_init(&q->requeue_lock); | |
2615 | ||
2616 | blk_queue_make_request(q, blk_mq_make_request); | |
2617 | if (q->mq_ops->poll) | |
2618 | q->poll_fn = blk_mq_poll; | |
2619 | ||
2620 | /* | |
2621 | * Do this after blk_queue_make_request() overrides it... | |
2622 | */ | |
2623 | q->nr_requests = set->queue_depth; | |
2624 | ||
2625 | /* | |
2626 | * Default to classic polling | |
2627 | */ | |
2628 | q->poll_nsec = -1; | |
2629 | ||
2630 | if (set->ops->complete) | |
2631 | blk_queue_softirq_done(q, set->ops->complete); | |
2632 | ||
2633 | blk_mq_init_cpu_queues(q, set->nr_hw_queues); | |
2634 | blk_mq_add_queue_tag_set(set, q); | |
2635 | blk_mq_map_swqueue(q); | |
2636 | ||
2637 | if (!(set->flags & BLK_MQ_F_NO_SCHED)) { | |
2638 | int ret; | |
2639 | ||
2640 | ret = elevator_init_mq(q); | |
2641 | if (ret) | |
2642 | return ERR_PTR(ret); | |
2643 | } | |
2644 | ||
2645 | return q; | |
2646 | ||
2647 | err_hctxs: | |
2648 | kfree(q->queue_hw_ctx); | |
2649 | err_percpu: | |
2650 | free_percpu(q->queue_ctx); | |
2651 | err_exit: | |
2652 | q->mq_ops = NULL; | |
2653 | return ERR_PTR(-ENOMEM); | |
2654 | } | |
2655 | EXPORT_SYMBOL(blk_mq_init_allocated_queue); | |
2656 | ||
2657 | void blk_mq_free_queue(struct request_queue *q) | |
2658 | { | |
2659 | struct blk_mq_tag_set *set = q->tag_set; | |
2660 | ||
2661 | blk_mq_del_queue_tag_set(q); | |
2662 | blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); | |
2663 | } | |
2664 | ||
2665 | /* Basically redo blk_mq_init_queue with queue frozen */ | |
2666 | static void blk_mq_queue_reinit(struct request_queue *q) | |
2667 | { | |
2668 | WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth)); | |
2669 | ||
2670 | blk_mq_debugfs_unregister_hctxs(q); | |
2671 | blk_mq_sysfs_unregister(q); | |
2672 | ||
2673 | /* | |
2674 | * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe | |
2675 | * we should change hctx numa_node according to the new topology (this | |
2676 | * involves freeing and re-allocating memory, worth doing?) | |
2677 | */ | |
2678 | blk_mq_map_swqueue(q); | |
2679 | ||
2680 | blk_mq_sysfs_register(q); | |
2681 | blk_mq_debugfs_register_hctxs(q); | |
2682 | } | |
2683 | ||
2684 | static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) | |
2685 | { | |
2686 | int i; | |
2687 | ||
2688 | for (i = 0; i < set->nr_hw_queues; i++) | |
2689 | if (!__blk_mq_alloc_rq_map(set, i)) | |
2690 | goto out_unwind; | |
2691 | ||
2692 | return 0; | |
2693 | ||
2694 | out_unwind: | |
2695 | while (--i >= 0) | |
2696 | blk_mq_free_rq_map(set->tags[i]); | |
2697 | ||
2698 | return -ENOMEM; | |
2699 | } | |
2700 | ||
2701 | /* | |
2702 | * Allocate the request maps associated with this tag_set. Note that this | |
2703 | * may reduce the depth asked for, if memory is tight. set->queue_depth | |
2704 | * will be updated to reflect the allocated depth. | |
2705 | */ | |
2706 | static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) | |
2707 | { | |
2708 | unsigned int depth; | |
2709 | int err; | |
2710 | ||
2711 | depth = set->queue_depth; | |
2712 | do { | |
2713 | err = __blk_mq_alloc_rq_maps(set); | |
2714 | if (!err) | |
2715 | break; | |
2716 | ||
2717 | set->queue_depth >>= 1; | |
2718 | if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { | |
2719 | err = -ENOMEM; | |
2720 | break; | |
2721 | } | |
2722 | } while (set->queue_depth); | |
2723 | ||
2724 | if (!set->queue_depth || err) { | |
2725 | pr_err("blk-mq: failed to allocate request map\n"); | |
2726 | return -ENOMEM; | |
2727 | } | |
2728 | ||
2729 | if (depth != set->queue_depth) | |
2730 | pr_info("blk-mq: reduced tag depth (%u -> %u)\n", | |
2731 | depth, set->queue_depth); | |
2732 | ||
2733 | return 0; | |
2734 | } | |
2735 | ||
2736 | static int blk_mq_update_queue_map(struct blk_mq_tag_set *set) | |
2737 | { | |
2738 | if (set->ops->map_queues) { | |
2739 | /* | |
2740 | * transport .map_queues is usually done in the following | |
2741 | * way: | |
2742 | * | |
2743 | * for (queue = 0; queue < set->nr_hw_queues; queue++) { | |
2744 | * mask = get_cpu_mask(queue) | |
2745 | * for_each_cpu(cpu, mask) | |
2746 | * set->mq_map[cpu] = queue; | |
2747 | * } | |
2748 | * | |
2749 | * When we need to remap, the table has to be cleared for | |
2750 | * killing stale mapping since one CPU may not be mapped | |
2751 | * to any hw queue. | |
2752 | */ | |
2753 | blk_mq_clear_mq_map(set); | |
2754 | ||
2755 | return set->ops->map_queues(set); | |
2756 | } else | |
2757 | return blk_mq_map_queues(set); | |
2758 | } | |
2759 | ||
2760 | /* | |
2761 | * Alloc a tag set to be associated with one or more request queues. | |
2762 | * May fail with EINVAL for various error conditions. May adjust the | |
2763 | * requested depth down, if it's too large. In that case, the set | |
2764 | * value will be stored in set->queue_depth. | |
2765 | */ | |
2766 | int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) | |
2767 | { | |
2768 | int ret; | |
2769 | ||
2770 | BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); | |
2771 | ||
2772 | if (!set->nr_hw_queues) | |
2773 | return -EINVAL; | |
2774 | if (!set->queue_depth) | |
2775 | return -EINVAL; | |
2776 | if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) | |
2777 | return -EINVAL; | |
2778 | ||
2779 | if (!set->ops->queue_rq) | |
2780 | return -EINVAL; | |
2781 | ||
2782 | if (!set->ops->get_budget ^ !set->ops->put_budget) | |
2783 | return -EINVAL; | |
2784 | ||
2785 | if (set->queue_depth > BLK_MQ_MAX_DEPTH) { | |
2786 | pr_info("blk-mq: reduced tag depth to %u\n", | |
2787 | BLK_MQ_MAX_DEPTH); | |
2788 | set->queue_depth = BLK_MQ_MAX_DEPTH; | |
2789 | } | |
2790 | ||
2791 | /* | |
2792 | * If a crashdump is active, then we are potentially in a very | |
2793 | * memory constrained environment. Limit us to 1 queue and | |
2794 | * 64 tags to prevent using too much memory. | |
2795 | */ | |
2796 | if (is_kdump_kernel()) { | |
2797 | set->nr_hw_queues = 1; | |
2798 | set->queue_depth = min(64U, set->queue_depth); | |
2799 | } | |
2800 | /* | |
2801 | * There is no use for more h/w queues than cpus. | |
2802 | */ | |
2803 | if (set->nr_hw_queues > nr_cpu_ids) | |
2804 | set->nr_hw_queues = nr_cpu_ids; | |
2805 | ||
2806 | set->tags = kcalloc_node(nr_cpu_ids, sizeof(struct blk_mq_tags *), | |
2807 | GFP_KERNEL, set->numa_node); | |
2808 | if (!set->tags) | |
2809 | return -ENOMEM; | |
2810 | ||
2811 | ret = -ENOMEM; | |
2812 | set->mq_map = kcalloc_node(nr_cpu_ids, sizeof(*set->mq_map), | |
2813 | GFP_KERNEL, set->numa_node); | |
2814 | if (!set->mq_map) | |
2815 | goto out_free_tags; | |
2816 | ||
2817 | ret = blk_mq_update_queue_map(set); | |
2818 | if (ret) | |
2819 | goto out_free_mq_map; | |
2820 | ||
2821 | ret = blk_mq_alloc_rq_maps(set); | |
2822 | if (ret) | |
2823 | goto out_free_mq_map; | |
2824 | ||
2825 | mutex_init(&set->tag_list_lock); | |
2826 | INIT_LIST_HEAD(&set->tag_list); | |
2827 | ||
2828 | return 0; | |
2829 | ||
2830 | out_free_mq_map: | |
2831 | kfree(set->mq_map); | |
2832 | set->mq_map = NULL; | |
2833 | out_free_tags: | |
2834 | kfree(set->tags); | |
2835 | set->tags = NULL; | |
2836 | return ret; | |
2837 | } | |
2838 | EXPORT_SYMBOL(blk_mq_alloc_tag_set); | |
2839 | ||
2840 | void blk_mq_free_tag_set(struct blk_mq_tag_set *set) | |
2841 | { | |
2842 | int i; | |
2843 | ||
2844 | for (i = 0; i < nr_cpu_ids; i++) | |
2845 | blk_mq_free_map_and_requests(set, i); | |
2846 | ||
2847 | kfree(set->mq_map); | |
2848 | set->mq_map = NULL; | |
2849 | ||
2850 | kfree(set->tags); | |
2851 | set->tags = NULL; | |
2852 | } | |
2853 | EXPORT_SYMBOL(blk_mq_free_tag_set); | |
2854 | ||
2855 | int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) | |
2856 | { | |
2857 | struct blk_mq_tag_set *set = q->tag_set; | |
2858 | struct blk_mq_hw_ctx *hctx; | |
2859 | int i, ret; | |
2860 | ||
2861 | if (!set) | |
2862 | return -EINVAL; | |
2863 | ||
2864 | blk_mq_freeze_queue(q); | |
2865 | blk_mq_quiesce_queue(q); | |
2866 | ||
2867 | ret = 0; | |
2868 | queue_for_each_hw_ctx(q, hctx, i) { | |
2869 | if (!hctx->tags) | |
2870 | continue; | |
2871 | /* | |
2872 | * If we're using an MQ scheduler, just update the scheduler | |
2873 | * queue depth. This is similar to what the old code would do. | |
2874 | */ | |
2875 | if (!hctx->sched_tags) { | |
2876 | ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr, | |
2877 | false); | |
2878 | } else { | |
2879 | ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags, | |
2880 | nr, true); | |
2881 | } | |
2882 | if (ret) | |
2883 | break; | |
2884 | } | |
2885 | ||
2886 | if (!ret) | |
2887 | q->nr_requests = nr; | |
2888 | ||
2889 | blk_mq_unquiesce_queue(q); | |
2890 | blk_mq_unfreeze_queue(q); | |
2891 | ||
2892 | return ret; | |
2893 | } | |
2894 | ||
2895 | /* | |
2896 | * request_queue and elevator_type pair. | |
2897 | * It is just used by __blk_mq_update_nr_hw_queues to cache | |
2898 | * the elevator_type associated with a request_queue. | |
2899 | */ | |
2900 | struct blk_mq_qe_pair { | |
2901 | struct list_head node; | |
2902 | struct request_queue *q; | |
2903 | struct elevator_type *type; | |
2904 | }; | |
2905 | ||
2906 | /* | |
2907 | * Cache the elevator_type in qe pair list and switch the | |
2908 | * io scheduler to 'none' | |
2909 | */ | |
2910 | static bool blk_mq_elv_switch_none(struct list_head *head, | |
2911 | struct request_queue *q) | |
2912 | { | |
2913 | struct blk_mq_qe_pair *qe; | |
2914 | ||
2915 | if (!q->elevator) | |
2916 | return true; | |
2917 | ||
2918 | qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY); | |
2919 | if (!qe) | |
2920 | return false; | |
2921 | ||
2922 | INIT_LIST_HEAD(&qe->node); | |
2923 | qe->q = q; | |
2924 | qe->type = q->elevator->type; | |
2925 | list_add(&qe->node, head); | |
2926 | ||
2927 | mutex_lock(&q->sysfs_lock); | |
2928 | /* | |
2929 | * After elevator_switch_mq, the previous elevator_queue will be | |
2930 | * released by elevator_release. The reference of the io scheduler | |
2931 | * module get by elevator_get will also be put. So we need to get | |
2932 | * a reference of the io scheduler module here to prevent it to be | |
2933 | * removed. | |
2934 | */ | |
2935 | __module_get(qe->type->elevator_owner); | |
2936 | elevator_switch_mq(q, NULL); | |
2937 | mutex_unlock(&q->sysfs_lock); | |
2938 | ||
2939 | return true; | |
2940 | } | |
2941 | ||
2942 | static void blk_mq_elv_switch_back(struct list_head *head, | |
2943 | struct request_queue *q) | |
2944 | { | |
2945 | struct blk_mq_qe_pair *qe; | |
2946 | struct elevator_type *t = NULL; | |
2947 | ||
2948 | list_for_each_entry(qe, head, node) | |
2949 | if (qe->q == q) { | |
2950 | t = qe->type; | |
2951 | break; | |
2952 | } | |
2953 | ||
2954 | if (!t) | |
2955 | return; | |
2956 | ||
2957 | list_del(&qe->node); | |
2958 | kfree(qe); | |
2959 | ||
2960 | mutex_lock(&q->sysfs_lock); | |
2961 | elevator_switch_mq(q, t); | |
2962 | mutex_unlock(&q->sysfs_lock); | |
2963 | } | |
2964 | ||
2965 | static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, | |
2966 | int nr_hw_queues) | |
2967 | { | |
2968 | struct request_queue *q; | |
2969 | LIST_HEAD(head); | |
2970 | ||
2971 | lockdep_assert_held(&set->tag_list_lock); | |
2972 | ||
2973 | if (nr_hw_queues > nr_cpu_ids) | |
2974 | nr_hw_queues = nr_cpu_ids; | |
2975 | if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues) | |
2976 | return; | |
2977 | ||
2978 | list_for_each_entry(q, &set->tag_list, tag_set_list) | |
2979 | blk_mq_freeze_queue(q); | |
2980 | /* | |
2981 | * Sync with blk_mq_queue_tag_busy_iter. | |
2982 | */ | |
2983 | synchronize_rcu(); | |
2984 | /* | |
2985 | * Switch IO scheduler to 'none', cleaning up the data associated | |
2986 | * with the previous scheduler. We will switch back once we are done | |
2987 | * updating the new sw to hw queue mappings. | |
2988 | */ | |
2989 | list_for_each_entry(q, &set->tag_list, tag_set_list) | |
2990 | if (!blk_mq_elv_switch_none(&head, q)) | |
2991 | goto switch_back; | |
2992 | ||
2993 | set->nr_hw_queues = nr_hw_queues; | |
2994 | blk_mq_update_queue_map(set); | |
2995 | list_for_each_entry(q, &set->tag_list, tag_set_list) { | |
2996 | blk_mq_realloc_hw_ctxs(set, q); | |
2997 | blk_mq_queue_reinit(q); | |
2998 | } | |
2999 | ||
3000 | switch_back: | |
3001 | list_for_each_entry(q, &set->tag_list, tag_set_list) | |
3002 | blk_mq_elv_switch_back(&head, q); | |
3003 | ||
3004 | list_for_each_entry(q, &set->tag_list, tag_set_list) | |
3005 | blk_mq_unfreeze_queue(q); | |
3006 | } | |
3007 | ||
3008 | void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) | |
3009 | { | |
3010 | mutex_lock(&set->tag_list_lock); | |
3011 | __blk_mq_update_nr_hw_queues(set, nr_hw_queues); | |
3012 | mutex_unlock(&set->tag_list_lock); | |
3013 | } | |
3014 | EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); | |
3015 | ||
3016 | /* Enable polling stats and return whether they were already enabled. */ | |
3017 | static bool blk_poll_stats_enable(struct request_queue *q) | |
3018 | { | |
3019 | if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || | |
3020 | blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS, q)) | |
3021 | return true; | |
3022 | blk_stat_add_callback(q, q->poll_cb); | |
3023 | return false; | |
3024 | } | |
3025 | ||
3026 | static void blk_mq_poll_stats_start(struct request_queue *q) | |
3027 | { | |
3028 | /* | |
3029 | * We don't arm the callback if polling stats are not enabled or the | |
3030 | * callback is already active. | |
3031 | */ | |
3032 | if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || | |
3033 | blk_stat_is_active(q->poll_cb)) | |
3034 | return; | |
3035 | ||
3036 | blk_stat_activate_msecs(q->poll_cb, 100); | |
3037 | } | |
3038 | ||
3039 | static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb) | |
3040 | { | |
3041 | struct request_queue *q = cb->data; | |
3042 | int bucket; | |
3043 | ||
3044 | for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) { | |
3045 | if (cb->stat[bucket].nr_samples) | |
3046 | q->poll_stat[bucket] = cb->stat[bucket]; | |
3047 | } | |
3048 | } | |
3049 | ||
3050 | static unsigned long blk_mq_poll_nsecs(struct request_queue *q, | |
3051 | struct blk_mq_hw_ctx *hctx, | |
3052 | struct request *rq) | |
3053 | { | |
3054 | unsigned long ret = 0; | |
3055 | int bucket; | |
3056 | ||
3057 | /* | |
3058 | * If stats collection isn't on, don't sleep but turn it on for | |
3059 | * future users | |
3060 | */ | |
3061 | if (!blk_poll_stats_enable(q)) | |
3062 | return 0; | |
3063 | ||
3064 | /* | |
3065 | * As an optimistic guess, use half of the mean service time | |
3066 | * for this type of request. We can (and should) make this smarter. | |
3067 | * For instance, if the completion latencies are tight, we can | |
3068 | * get closer than just half the mean. This is especially | |
3069 | * important on devices where the completion latencies are longer | |
3070 | * than ~10 usec. We do use the stats for the relevant IO size | |
3071 | * if available which does lead to better estimates. | |
3072 | */ | |
3073 | bucket = blk_mq_poll_stats_bkt(rq); | |
3074 | if (bucket < 0) | |
3075 | return ret; | |
3076 | ||
3077 | if (q->poll_stat[bucket].nr_samples) | |
3078 | ret = (q->poll_stat[bucket].mean + 1) / 2; | |
3079 | ||
3080 | return ret; | |
3081 | } | |
3082 | ||
3083 | static bool blk_mq_poll_hybrid_sleep(struct request_queue *q, | |
3084 | struct blk_mq_hw_ctx *hctx, | |
3085 | struct request *rq) | |
3086 | { | |
3087 | struct hrtimer_sleeper hs; | |
3088 | enum hrtimer_mode mode; | |
3089 | unsigned int nsecs; | |
3090 | ktime_t kt; | |
3091 | ||
3092 | if (rq->rq_flags & RQF_MQ_POLL_SLEPT) | |
3093 | return false; | |
3094 | ||
3095 | /* | |
3096 | * poll_nsec can be: | |
3097 | * | |
3098 | * -1: don't ever hybrid sleep | |
3099 | * 0: use half of prev avg | |
3100 | * >0: use this specific value | |
3101 | */ | |
3102 | if (q->poll_nsec == -1) | |
3103 | return false; | |
3104 | else if (q->poll_nsec > 0) | |
3105 | nsecs = q->poll_nsec; | |
3106 | else | |
3107 | nsecs = blk_mq_poll_nsecs(q, hctx, rq); | |
3108 | ||
3109 | if (!nsecs) | |
3110 | return false; | |
3111 | ||
3112 | rq->rq_flags |= RQF_MQ_POLL_SLEPT; | |
3113 | ||
3114 | /* | |
3115 | * This will be replaced with the stats tracking code, using | |
3116 | * 'avg_completion_time / 2' as the pre-sleep target. | |
3117 | */ | |
3118 | kt = nsecs; | |
3119 | ||
3120 | mode = HRTIMER_MODE_REL; | |
3121 | hrtimer_init_on_stack(&hs.timer, CLOCK_MONOTONIC, mode); | |
3122 | hrtimer_set_expires(&hs.timer, kt); | |
3123 | ||
3124 | hrtimer_init_sleeper(&hs, current); | |
3125 | do { | |
3126 | if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE) | |
3127 | break; | |
3128 | set_current_state(TASK_UNINTERRUPTIBLE); | |
3129 | hrtimer_start_expires(&hs.timer, mode); | |
3130 | if (hs.task) | |
3131 | io_schedule(); | |
3132 | hrtimer_cancel(&hs.timer); | |
3133 | mode = HRTIMER_MODE_ABS; | |
3134 | } while (hs.task && !signal_pending(current)); | |
3135 | ||
3136 | __set_current_state(TASK_RUNNING); | |
3137 | destroy_hrtimer_on_stack(&hs.timer); | |
3138 | return true; | |
3139 | } | |
3140 | ||
3141 | static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq) | |
3142 | { | |
3143 | struct request_queue *q = hctx->queue; | |
3144 | long state; | |
3145 | ||
3146 | /* | |
3147 | * If we sleep, have the caller restart the poll loop to reset | |
3148 | * the state. Like for the other success return cases, the | |
3149 | * caller is responsible for checking if the IO completed. If | |
3150 | * the IO isn't complete, we'll get called again and will go | |
3151 | * straight to the busy poll loop. | |
3152 | */ | |
3153 | if (blk_mq_poll_hybrid_sleep(q, hctx, rq)) | |
3154 | return true; | |
3155 | ||
3156 | hctx->poll_considered++; | |
3157 | ||
3158 | state = current->state; | |
3159 | while (!need_resched()) { | |
3160 | int ret; | |
3161 | ||
3162 | hctx->poll_invoked++; | |
3163 | ||
3164 | ret = q->mq_ops->poll(hctx, rq->tag); | |
3165 | if (ret > 0) { | |
3166 | hctx->poll_success++; | |
3167 | set_current_state(TASK_RUNNING); | |
3168 | return true; | |
3169 | } | |
3170 | ||
3171 | if (signal_pending_state(state, current)) | |
3172 | set_current_state(TASK_RUNNING); | |
3173 | ||
3174 | if (current->state == TASK_RUNNING) | |
3175 | return true; | |
3176 | if (ret < 0) | |
3177 | break; | |
3178 | cpu_relax(); | |
3179 | } | |
3180 | ||
3181 | __set_current_state(TASK_RUNNING); | |
3182 | return false; | |
3183 | } | |
3184 | ||
3185 | static bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie) | |
3186 | { | |
3187 | struct blk_mq_hw_ctx *hctx; | |
3188 | struct request *rq; | |
3189 | ||
3190 | if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) | |
3191 | return false; | |
3192 | ||
3193 | hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; | |
3194 | if (!blk_qc_t_is_internal(cookie)) | |
3195 | rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie)); | |
3196 | else { | |
3197 | rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie)); | |
3198 | /* | |
3199 | * With scheduling, if the request has completed, we'll | |
3200 | * get a NULL return here, as we clear the sched tag when | |
3201 | * that happens. The request still remains valid, like always, | |
3202 | * so we should be safe with just the NULL check. | |
3203 | */ | |
3204 | if (!rq) | |
3205 | return false; | |
3206 | } | |
3207 | ||
3208 | return __blk_mq_poll(hctx, rq); | |
3209 | } | |
3210 | ||
3211 | static int __init blk_mq_init(void) | |
3212 | { | |
3213 | cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, | |
3214 | blk_mq_hctx_notify_dead); | |
3215 | return 0; | |
3216 | } | |
3217 | subsys_initcall(blk_mq_init); |