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3dcf60bc | 1 | // SPDX-License-Identifier: GPL-2.0 |
bd166ef1 JA |
2 | /* |
3 | * blk-mq scheduling framework | |
4 | * | |
5 | * Copyright (C) 2016 Jens Axboe | |
6 | */ | |
7 | #include <linux/kernel.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/blk-mq.h> | |
10 | ||
11 | #include <trace/events/block.h> | |
12 | ||
13 | #include "blk.h" | |
14 | #include "blk-mq.h" | |
d332ce09 | 15 | #include "blk-mq-debugfs.h" |
bd166ef1 JA |
16 | #include "blk-mq-sched.h" |
17 | #include "blk-mq-tag.h" | |
18 | #include "blk-wbt.h" | |
19 | ||
20 | void blk_mq_sched_free_hctx_data(struct request_queue *q, | |
21 | void (*exit)(struct blk_mq_hw_ctx *)) | |
22 | { | |
23 | struct blk_mq_hw_ctx *hctx; | |
24 | int i; | |
25 | ||
26 | queue_for_each_hw_ctx(q, hctx, i) { | |
27 | if (exit && hctx->sched_data) | |
28 | exit(hctx); | |
29 | kfree(hctx->sched_data); | |
30 | hctx->sched_data = NULL; | |
31 | } | |
32 | } | |
33 | EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data); | |
34 | ||
e2b3fa5a | 35 | void blk_mq_sched_assign_ioc(struct request *rq) |
bd166ef1 | 36 | { |
44e8c2bf | 37 | struct request_queue *q = rq->q; |
0c62bff1 | 38 | struct io_context *ioc; |
bd166ef1 JA |
39 | struct io_cq *icq; |
40 | ||
0c62bff1 JA |
41 | /* |
42 | * May not have an IO context if it's a passthrough request | |
43 | */ | |
44 | ioc = current->io_context; | |
45 | if (!ioc) | |
46 | return; | |
47 | ||
0d945c1f | 48 | spin_lock_irq(&q->queue_lock); |
bd166ef1 | 49 | icq = ioc_lookup_icq(ioc, q); |
0d945c1f | 50 | spin_unlock_irq(&q->queue_lock); |
bd166ef1 JA |
51 | |
52 | if (!icq) { | |
53 | icq = ioc_create_icq(ioc, q, GFP_ATOMIC); | |
54 | if (!icq) | |
55 | return; | |
56 | } | |
ea511e3c | 57 | get_io_context(icq->ioc); |
44e8c2bf | 58 | rq->elv.icq = icq; |
bd166ef1 JA |
59 | } |
60 | ||
8e8320c9 JA |
61 | /* |
62 | * Mark a hardware queue as needing a restart. For shared queues, maintain | |
63 | * a count of how many hardware queues are marked for restart. | |
64 | */ | |
7211aef8 | 65 | void blk_mq_sched_mark_restart_hctx(struct blk_mq_hw_ctx *hctx) |
8e8320c9 JA |
66 | { |
67 | if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) | |
68 | return; | |
69 | ||
97889f9a | 70 | set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); |
8e8320c9 | 71 | } |
7211aef8 | 72 | EXPORT_SYMBOL_GPL(blk_mq_sched_mark_restart_hctx); |
8e8320c9 | 73 | |
97889f9a | 74 | void blk_mq_sched_restart(struct blk_mq_hw_ctx *hctx) |
8e8320c9 JA |
75 | { |
76 | if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) | |
97889f9a ML |
77 | return; |
78 | clear_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); | |
8e8320c9 | 79 | |
97889f9a | 80 | blk_mq_run_hw_queue(hctx, true); |
8e8320c9 JA |
81 | } |
82 | ||
1f460b63 ML |
83 | /* |
84 | * Only SCSI implements .get_budget and .put_budget, and SCSI restarts | |
85 | * its queue by itself in its completion handler, so we don't need to | |
86 | * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE. | |
87 | */ | |
88 | static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) | |
caf8eb0d ML |
89 | { |
90 | struct request_queue *q = hctx->queue; | |
91 | struct elevator_queue *e = q->elevator; | |
92 | LIST_HEAD(rq_list); | |
93 | ||
94 | do { | |
de148297 | 95 | struct request *rq; |
caf8eb0d | 96 | |
f9cd4bfe | 97 | if (e->type->ops.has_work && !e->type->ops.has_work(hctx)) |
caf8eb0d | 98 | break; |
de148297 | 99 | |
88022d72 | 100 | if (!blk_mq_get_dispatch_budget(hctx)) |
1f460b63 | 101 | break; |
de148297 | 102 | |
f9cd4bfe | 103 | rq = e->type->ops.dispatch_request(hctx); |
de148297 ML |
104 | if (!rq) { |
105 | blk_mq_put_dispatch_budget(hctx); | |
106 | break; | |
de148297 ML |
107 | } |
108 | ||
109 | /* | |
110 | * Now this rq owns the budget which has to be released | |
111 | * if this rq won't be queued to driver via .queue_rq() | |
112 | * in blk_mq_dispatch_rq_list(). | |
113 | */ | |
caf8eb0d | 114 | list_add(&rq->queuelist, &rq_list); |
de148297 | 115 | } while (blk_mq_dispatch_rq_list(q, &rq_list, true)); |
caf8eb0d ML |
116 | } |
117 | ||
b347689f ML |
118 | static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx, |
119 | struct blk_mq_ctx *ctx) | |
120 | { | |
f31967f0 | 121 | unsigned short idx = ctx->index_hw[hctx->type]; |
b347689f ML |
122 | |
123 | if (++idx == hctx->nr_ctx) | |
124 | idx = 0; | |
125 | ||
126 | return hctx->ctxs[idx]; | |
127 | } | |
128 | ||
1f460b63 ML |
129 | /* |
130 | * Only SCSI implements .get_budget and .put_budget, and SCSI restarts | |
131 | * its queue by itself in its completion handler, so we don't need to | |
132 | * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE. | |
133 | */ | |
134 | static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx) | |
b347689f ML |
135 | { |
136 | struct request_queue *q = hctx->queue; | |
137 | LIST_HEAD(rq_list); | |
138 | struct blk_mq_ctx *ctx = READ_ONCE(hctx->dispatch_from); | |
139 | ||
140 | do { | |
141 | struct request *rq; | |
b347689f ML |
142 | |
143 | if (!sbitmap_any_bit_set(&hctx->ctx_map)) | |
144 | break; | |
145 | ||
88022d72 | 146 | if (!blk_mq_get_dispatch_budget(hctx)) |
1f460b63 | 147 | break; |
b347689f ML |
148 | |
149 | rq = blk_mq_dequeue_from_ctx(hctx, ctx); | |
150 | if (!rq) { | |
151 | blk_mq_put_dispatch_budget(hctx); | |
152 | break; | |
b347689f ML |
153 | } |
154 | ||
155 | /* | |
156 | * Now this rq owns the budget which has to be released | |
157 | * if this rq won't be queued to driver via .queue_rq() | |
158 | * in blk_mq_dispatch_rq_list(). | |
159 | */ | |
160 | list_add(&rq->queuelist, &rq_list); | |
161 | ||
162 | /* round robin for fair dispatch */ | |
163 | ctx = blk_mq_next_ctx(hctx, rq->mq_ctx); | |
164 | ||
165 | } while (blk_mq_dispatch_rq_list(q, &rq_list, true)); | |
166 | ||
167 | WRITE_ONCE(hctx->dispatch_from, ctx); | |
b347689f ML |
168 | } |
169 | ||
1f460b63 | 170 | void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) |
bd166ef1 | 171 | { |
81380ca1 OS |
172 | struct request_queue *q = hctx->queue; |
173 | struct elevator_queue *e = q->elevator; | |
f9cd4bfe | 174 | const bool has_sched_dispatch = e && e->type->ops.dispatch_request; |
bd166ef1 JA |
175 | LIST_HEAD(rq_list); |
176 | ||
f4560ffe ML |
177 | /* RCU or SRCU read lock is needed before checking quiesced flag */ |
178 | if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) | |
1f460b63 | 179 | return; |
bd166ef1 JA |
180 | |
181 | hctx->run++; | |
182 | ||
183 | /* | |
184 | * If we have previous entries on our dispatch list, grab them first for | |
185 | * more fair dispatch. | |
186 | */ | |
187 | if (!list_empty_careful(&hctx->dispatch)) { | |
188 | spin_lock(&hctx->lock); | |
189 | if (!list_empty(&hctx->dispatch)) | |
190 | list_splice_init(&hctx->dispatch, &rq_list); | |
191 | spin_unlock(&hctx->lock); | |
192 | } | |
193 | ||
194 | /* | |
195 | * Only ask the scheduler for requests, if we didn't have residual | |
196 | * requests from the dispatch list. This is to avoid the case where | |
197 | * we only ever dispatch a fraction of the requests available because | |
198 | * of low device queue depth. Once we pull requests out of the IO | |
199 | * scheduler, we can no longer merge or sort them. So it's best to | |
200 | * leave them there for as long as we can. Mark the hw queue as | |
201 | * needing a restart in that case. | |
caf8eb0d ML |
202 | * |
203 | * We want to dispatch from the scheduler if there was nothing | |
204 | * on the dispatch list or we were able to dispatch from the | |
205 | * dispatch list. | |
bd166ef1 | 206 | */ |
c13660a0 | 207 | if (!list_empty(&rq_list)) { |
d38d3515 | 208 | blk_mq_sched_mark_restart_hctx(hctx); |
b347689f ML |
209 | if (blk_mq_dispatch_rq_list(q, &rq_list, false)) { |
210 | if (has_sched_dispatch) | |
1f460b63 | 211 | blk_mq_do_dispatch_sched(hctx); |
b347689f | 212 | else |
1f460b63 | 213 | blk_mq_do_dispatch_ctx(hctx); |
b347689f | 214 | } |
caf8eb0d | 215 | } else if (has_sched_dispatch) { |
1f460b63 | 216 | blk_mq_do_dispatch_sched(hctx); |
6e768717 ML |
217 | } else if (hctx->dispatch_busy) { |
218 | /* dequeue request one by one from sw queue if queue is busy */ | |
1f460b63 | 219 | blk_mq_do_dispatch_ctx(hctx); |
caf8eb0d | 220 | } else { |
c13660a0 | 221 | blk_mq_flush_busy_ctxs(hctx, &rq_list); |
de148297 | 222 | blk_mq_dispatch_rq_list(q, &rq_list, false); |
64765a75 | 223 | } |
bd166ef1 JA |
224 | } |
225 | ||
e4d750c9 | 226 | bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, |
14ccb66b | 227 | unsigned int nr_segs, struct request **merged_request) |
bd166ef1 JA |
228 | { |
229 | struct request *rq; | |
bd166ef1 | 230 | |
34fe7c05 CH |
231 | switch (elv_merge(q, &rq, bio)) { |
232 | case ELEVATOR_BACK_MERGE: | |
bd166ef1 JA |
233 | if (!blk_mq_sched_allow_merge(q, rq, bio)) |
234 | return false; | |
14ccb66b | 235 | if (!bio_attempt_back_merge(rq, bio, nr_segs)) |
34fe7c05 CH |
236 | return false; |
237 | *merged_request = attempt_back_merge(q, rq); | |
238 | if (!*merged_request) | |
239 | elv_merged_request(q, rq, ELEVATOR_BACK_MERGE); | |
240 | return true; | |
241 | case ELEVATOR_FRONT_MERGE: | |
bd166ef1 JA |
242 | if (!blk_mq_sched_allow_merge(q, rq, bio)) |
243 | return false; | |
14ccb66b | 244 | if (!bio_attempt_front_merge(rq, bio, nr_segs)) |
34fe7c05 CH |
245 | return false; |
246 | *merged_request = attempt_front_merge(q, rq); | |
247 | if (!*merged_request) | |
248 | elv_merged_request(q, rq, ELEVATOR_FRONT_MERGE); | |
249 | return true; | |
bea99a50 KB |
250 | case ELEVATOR_DISCARD_MERGE: |
251 | return bio_attempt_discard_merge(q, rq, bio); | |
34fe7c05 CH |
252 | default: |
253 | return false; | |
bd166ef1 | 254 | } |
bd166ef1 JA |
255 | } |
256 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); | |
257 | ||
9bddeb2a | 258 | /* |
9c558734 JA |
259 | * Iterate list of requests and see if we can merge this bio with any |
260 | * of them. | |
9bddeb2a | 261 | */ |
9c558734 | 262 | bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list, |
14ccb66b | 263 | struct bio *bio, unsigned int nr_segs) |
9bddeb2a ML |
264 | { |
265 | struct request *rq; | |
266 | int checked = 8; | |
267 | ||
9c558734 | 268 | list_for_each_entry_reverse(rq, list, queuelist) { |
9bddeb2a ML |
269 | bool merged = false; |
270 | ||
271 | if (!checked--) | |
272 | break; | |
273 | ||
274 | if (!blk_rq_merge_ok(rq, bio)) | |
275 | continue; | |
276 | ||
277 | switch (blk_try_merge(rq, bio)) { | |
278 | case ELEVATOR_BACK_MERGE: | |
279 | if (blk_mq_sched_allow_merge(q, rq, bio)) | |
14ccb66b CH |
280 | merged = bio_attempt_back_merge(rq, bio, |
281 | nr_segs); | |
9bddeb2a ML |
282 | break; |
283 | case ELEVATOR_FRONT_MERGE: | |
284 | if (blk_mq_sched_allow_merge(q, rq, bio)) | |
14ccb66b CH |
285 | merged = bio_attempt_front_merge(rq, bio, |
286 | nr_segs); | |
9bddeb2a ML |
287 | break; |
288 | case ELEVATOR_DISCARD_MERGE: | |
289 | merged = bio_attempt_discard_merge(q, rq, bio); | |
290 | break; | |
291 | default: | |
292 | continue; | |
293 | } | |
294 | ||
9bddeb2a ML |
295 | return merged; |
296 | } | |
297 | ||
298 | return false; | |
299 | } | |
9c558734 JA |
300 | EXPORT_SYMBOL_GPL(blk_mq_bio_list_merge); |
301 | ||
302 | /* | |
303 | * Reverse check our software queue for entries that we could potentially | |
304 | * merge with. Currently includes a hand-wavy stop count of 8, to not spend | |
305 | * too much time checking for merges. | |
306 | */ | |
307 | static bool blk_mq_attempt_merge(struct request_queue *q, | |
c16d6b5a | 308 | struct blk_mq_hw_ctx *hctx, |
14ccb66b CH |
309 | struct blk_mq_ctx *ctx, struct bio *bio, |
310 | unsigned int nr_segs) | |
9c558734 | 311 | { |
c16d6b5a ML |
312 | enum hctx_type type = hctx->type; |
313 | ||
9c558734 JA |
314 | lockdep_assert_held(&ctx->lock); |
315 | ||
14ccb66b | 316 | if (blk_mq_bio_list_merge(q, &ctx->rq_lists[type], bio, nr_segs)) { |
9c558734 JA |
317 | ctx->rq_merged++; |
318 | return true; | |
319 | } | |
320 | ||
321 | return false; | |
322 | } | |
9bddeb2a | 323 | |
14ccb66b CH |
324 | bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio, |
325 | unsigned int nr_segs) | |
bd166ef1 JA |
326 | { |
327 | struct elevator_queue *e = q->elevator; | |
9bddeb2a | 328 | struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); |
8ccdf4a3 | 329 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, bio->bi_opf, ctx); |
9bddeb2a | 330 | bool ret = false; |
c16d6b5a | 331 | enum hctx_type type; |
bd166ef1 | 332 | |
c05f4220 | 333 | if (e && e->type->ops.bio_merge) |
14ccb66b | 334 | return e->type->ops.bio_merge(hctx, bio, nr_segs); |
bd166ef1 | 335 | |
c16d6b5a | 336 | type = hctx->type; |
b04f50ab | 337 | if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) && |
c16d6b5a | 338 | !list_empty_careful(&ctx->rq_lists[type])) { |
9bddeb2a ML |
339 | /* default per sw-queue merge */ |
340 | spin_lock(&ctx->lock); | |
14ccb66b | 341 | ret = blk_mq_attempt_merge(q, hctx, ctx, bio, nr_segs); |
9bddeb2a ML |
342 | spin_unlock(&ctx->lock); |
343 | } | |
344 | ||
9bddeb2a | 345 | return ret; |
bd166ef1 JA |
346 | } |
347 | ||
348 | bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq) | |
349 | { | |
350 | return rq_mergeable(rq) && elv_attempt_insert_merge(q, rq); | |
351 | } | |
352 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_insert_merge); | |
353 | ||
354 | void blk_mq_sched_request_inserted(struct request *rq) | |
355 | { | |
356 | trace_block_rq_insert(rq->q, rq); | |
357 | } | |
358 | EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted); | |
359 | ||
0cacba6c | 360 | static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx, |
a6a252e6 | 361 | bool has_sched, |
0cacba6c | 362 | struct request *rq) |
bd166ef1 | 363 | { |
01e99aec ML |
364 | /* |
365 | * dispatch flush and passthrough rq directly | |
366 | * | |
367 | * passthrough request has to be added to hctx->dispatch directly. | |
368 | * For some reason, device may be in one situation which can't | |
369 | * handle FS request, so STS_RESOURCE is always returned and the | |
370 | * FS request will be added to hctx->dispatch. However passthrough | |
371 | * request may be required at that time for fixing the problem. If | |
372 | * passthrough request is added to scheduler queue, there isn't any | |
373 | * chance to dispatch it given we prioritize requests in hctx->dispatch. | |
374 | */ | |
375 | if ((rq->rq_flags & RQF_FLUSH_SEQ) || blk_rq_is_passthrough(rq)) | |
a6a252e6 | 376 | return true; |
a6a252e6 | 377 | |
923218f6 | 378 | if (has_sched) |
bd166ef1 | 379 | rq->rq_flags |= RQF_SORTED; |
bd166ef1 | 380 | |
a6a252e6 | 381 | return false; |
bd166ef1 | 382 | } |
bd166ef1 | 383 | |
bd6737f1 | 384 | void blk_mq_sched_insert_request(struct request *rq, bool at_head, |
9e97d295 | 385 | bool run_queue, bool async) |
bd6737f1 JA |
386 | { |
387 | struct request_queue *q = rq->q; | |
388 | struct elevator_queue *e = q->elevator; | |
389 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
ea4f995e | 390 | struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
bd6737f1 | 391 | |
a6a252e6 ML |
392 | /* flush rq in flush machinery need to be dispatched directly */ |
393 | if (!(rq->rq_flags & RQF_FLUSH_SEQ) && op_is_flush(rq->cmd_flags)) { | |
923218f6 ML |
394 | blk_insert_flush(rq); |
395 | goto run; | |
bd6737f1 JA |
396 | } |
397 | ||
923218f6 ML |
398 | WARN_ON(e && (rq->tag != -1)); |
399 | ||
01e99aec | 400 | if (blk_mq_sched_bypass_insert(hctx, !!e, rq)) { |
cc3200ea ML |
401 | /* |
402 | * Firstly normal IO request is inserted to scheduler queue or | |
403 | * sw queue, meantime we add flush request to dispatch queue( | |
404 | * hctx->dispatch) directly and there is at most one in-flight | |
405 | * flush request for each hw queue, so it doesn't matter to add | |
406 | * flush request to tail or front of the dispatch queue. | |
407 | * | |
408 | * Secondly in case of NCQ, flush request belongs to non-NCQ | |
409 | * command, and queueing it will fail when there is any | |
410 | * in-flight normal IO request(NCQ command). When adding flush | |
411 | * rq to the front of hctx->dispatch, it is easier to introduce | |
412 | * extra time to flush rq's latency because of S_SCHED_RESTART | |
413 | * compared with adding to the tail of dispatch queue, then | |
414 | * chance of flush merge is increased, and less flush requests | |
415 | * will be issued to controller. It is observed that ~10% time | |
416 | * is saved in blktests block/004 on disk attached to AHCI/NCQ | |
417 | * drive when adding flush rq to the front of hctx->dispatch. | |
418 | * | |
419 | * Simply queue flush rq to the front of hctx->dispatch so that | |
420 | * intensive flush workloads can benefit in case of NCQ HW. | |
421 | */ | |
422 | at_head = (rq->rq_flags & RQF_FLUSH_SEQ) ? true : at_head; | |
01e99aec | 423 | blk_mq_request_bypass_insert(rq, at_head, false); |
0cacba6c | 424 | goto run; |
01e99aec | 425 | } |
0cacba6c | 426 | |
f9cd4bfe | 427 | if (e && e->type->ops.insert_requests) { |
bd6737f1 JA |
428 | LIST_HEAD(list); |
429 | ||
430 | list_add(&rq->queuelist, &list); | |
f9cd4bfe | 431 | e->type->ops.insert_requests(hctx, &list, at_head); |
bd6737f1 JA |
432 | } else { |
433 | spin_lock(&ctx->lock); | |
434 | __blk_mq_insert_request(hctx, rq, at_head); | |
435 | spin_unlock(&ctx->lock); | |
436 | } | |
437 | ||
0cacba6c | 438 | run: |
bd6737f1 JA |
439 | if (run_queue) |
440 | blk_mq_run_hw_queue(hctx, async); | |
441 | } | |
442 | ||
67cae4c9 | 443 | void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx, |
bd6737f1 JA |
444 | struct blk_mq_ctx *ctx, |
445 | struct list_head *list, bool run_queue_async) | |
446 | { | |
f9afca4d | 447 | struct elevator_queue *e; |
e87eb301 ML |
448 | struct request_queue *q = hctx->queue; |
449 | ||
450 | /* | |
451 | * blk_mq_sched_insert_requests() is called from flush plug | |
452 | * context only, and hold one usage counter to prevent queue | |
453 | * from being released. | |
454 | */ | |
455 | percpu_ref_get(&q->q_usage_counter); | |
bd6737f1 | 456 | |
f9afca4d | 457 | e = hctx->queue->elevator; |
f9cd4bfe JA |
458 | if (e && e->type->ops.insert_requests) |
459 | e->type->ops.insert_requests(hctx, list, false); | |
6ce3dd6e ML |
460 | else { |
461 | /* | |
462 | * try to issue requests directly if the hw queue isn't | |
463 | * busy in case of 'none' scheduler, and this way may save | |
464 | * us one extra enqueue & dequeue to sw queue. | |
465 | */ | |
fd9c40f6 | 466 | if (!hctx->dispatch_busy && !e && !run_queue_async) { |
6ce3dd6e | 467 | blk_mq_try_issue_list_directly(hctx, list); |
fd9c40f6 | 468 | if (list_empty(list)) |
e87eb301 | 469 | goto out; |
fd9c40f6 BVA |
470 | } |
471 | blk_mq_insert_requests(hctx, ctx, list); | |
6ce3dd6e | 472 | } |
bd6737f1 JA |
473 | |
474 | blk_mq_run_hw_queue(hctx, run_queue_async); | |
e87eb301 ML |
475 | out: |
476 | percpu_ref_put(&q->q_usage_counter); | |
bd6737f1 JA |
477 | } |
478 | ||
bd166ef1 JA |
479 | static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, |
480 | struct blk_mq_hw_ctx *hctx, | |
481 | unsigned int hctx_idx) | |
482 | { | |
483 | if (hctx->sched_tags) { | |
484 | blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx); | |
485 | blk_mq_free_rq_map(hctx->sched_tags); | |
486 | hctx->sched_tags = NULL; | |
487 | } | |
488 | } | |
489 | ||
6917ff0b OS |
490 | static int blk_mq_sched_alloc_tags(struct request_queue *q, |
491 | struct blk_mq_hw_ctx *hctx, | |
492 | unsigned int hctx_idx) | |
493 | { | |
494 | struct blk_mq_tag_set *set = q->tag_set; | |
495 | int ret; | |
496 | ||
497 | hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests, | |
498 | set->reserved_tags); | |
499 | if (!hctx->sched_tags) | |
500 | return -ENOMEM; | |
501 | ||
502 | ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests); | |
503 | if (ret) | |
504 | blk_mq_sched_free_tags(set, hctx, hctx_idx); | |
505 | ||
506 | return ret; | |
507 | } | |
508 | ||
c3e22192 | 509 | /* called in queue's release handler, tagset has gone away */ |
54d5329d | 510 | static void blk_mq_sched_tags_teardown(struct request_queue *q) |
bd166ef1 | 511 | { |
bd166ef1 | 512 | struct blk_mq_hw_ctx *hctx; |
6917ff0b OS |
513 | int i; |
514 | ||
c3e22192 ML |
515 | queue_for_each_hw_ctx(q, hctx, i) { |
516 | if (hctx->sched_tags) { | |
517 | blk_mq_free_rq_map(hctx->sched_tags); | |
518 | hctx->sched_tags = NULL; | |
519 | } | |
520 | } | |
6917ff0b OS |
521 | } |
522 | ||
523 | int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e) | |
524 | { | |
525 | struct blk_mq_hw_ctx *hctx; | |
ee056f98 | 526 | struct elevator_queue *eq; |
6917ff0b OS |
527 | unsigned int i; |
528 | int ret; | |
529 | ||
530 | if (!e) { | |
531 | q->elevator = NULL; | |
32a50fab | 532 | q->nr_requests = q->tag_set->queue_depth; |
6917ff0b OS |
533 | return 0; |
534 | } | |
bd166ef1 JA |
535 | |
536 | /* | |
32825c45 ML |
537 | * Default to double of smaller one between hw queue_depth and 128, |
538 | * since we don't split into sync/async like the old code did. | |
539 | * Additionally, this is a per-hw queue depth. | |
bd166ef1 | 540 | */ |
32825c45 ML |
541 | q->nr_requests = 2 * min_t(unsigned int, q->tag_set->queue_depth, |
542 | BLKDEV_MAX_RQ); | |
bd166ef1 | 543 | |
bd166ef1 | 544 | queue_for_each_hw_ctx(q, hctx, i) { |
6917ff0b | 545 | ret = blk_mq_sched_alloc_tags(q, hctx, i); |
bd166ef1 | 546 | if (ret) |
6917ff0b | 547 | goto err; |
bd166ef1 JA |
548 | } |
549 | ||
f9cd4bfe | 550 | ret = e->ops.init_sched(q, e); |
6917ff0b OS |
551 | if (ret) |
552 | goto err; | |
bd166ef1 | 553 | |
d332ce09 OS |
554 | blk_mq_debugfs_register_sched(q); |
555 | ||
556 | queue_for_each_hw_ctx(q, hctx, i) { | |
f9cd4bfe JA |
557 | if (e->ops.init_hctx) { |
558 | ret = e->ops.init_hctx(hctx, i); | |
ee056f98 OS |
559 | if (ret) { |
560 | eq = q->elevator; | |
c3e22192 | 561 | blk_mq_sched_free_requests(q); |
ee056f98 OS |
562 | blk_mq_exit_sched(q, eq); |
563 | kobject_put(&eq->kobj); | |
564 | return ret; | |
565 | } | |
566 | } | |
d332ce09 | 567 | blk_mq_debugfs_register_sched_hctx(q, hctx); |
ee056f98 OS |
568 | } |
569 | ||
bd166ef1 | 570 | return 0; |
bd166ef1 | 571 | |
6917ff0b | 572 | err: |
c3e22192 | 573 | blk_mq_sched_free_requests(q); |
54d5329d OS |
574 | blk_mq_sched_tags_teardown(q); |
575 | q->elevator = NULL; | |
6917ff0b | 576 | return ret; |
bd166ef1 | 577 | } |
d3484991 | 578 | |
c3e22192 ML |
579 | /* |
580 | * called in either blk_queue_cleanup or elevator_switch, tagset | |
581 | * is required for freeing requests | |
582 | */ | |
583 | void blk_mq_sched_free_requests(struct request_queue *q) | |
584 | { | |
585 | struct blk_mq_hw_ctx *hctx; | |
586 | int i; | |
587 | ||
c3e22192 ML |
588 | queue_for_each_hw_ctx(q, hctx, i) { |
589 | if (hctx->sched_tags) | |
590 | blk_mq_free_rqs(q->tag_set, hctx->sched_tags, i); | |
591 | } | |
592 | } | |
593 | ||
54d5329d OS |
594 | void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e) |
595 | { | |
ee056f98 OS |
596 | struct blk_mq_hw_ctx *hctx; |
597 | unsigned int i; | |
598 | ||
d332ce09 OS |
599 | queue_for_each_hw_ctx(q, hctx, i) { |
600 | blk_mq_debugfs_unregister_sched_hctx(hctx); | |
f9cd4bfe JA |
601 | if (e->type->ops.exit_hctx && hctx->sched_data) { |
602 | e->type->ops.exit_hctx(hctx, i); | |
d332ce09 | 603 | hctx->sched_data = NULL; |
ee056f98 OS |
604 | } |
605 | } | |
d332ce09 | 606 | blk_mq_debugfs_unregister_sched(q); |
f9cd4bfe JA |
607 | if (e->type->ops.exit_sched) |
608 | e->type->ops.exit_sched(e); | |
54d5329d OS |
609 | blk_mq_sched_tags_teardown(q); |
610 | q->elevator = NULL; | |
611 | } |