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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 JA |
226 | bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, |
227 | 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; | |
34fe7c05 CH |
235 | if (!bio_attempt_back_merge(q, rq, bio)) |
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; | |
34fe7c05 CH |
244 | if (!bio_attempt_front_merge(q, rq, bio)) |
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 JA |
262 | bool blk_mq_bio_list_merge(struct request_queue *q, struct list_head *list, |
263 | struct bio *bio) | |
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)) | |
280 | merged = bio_attempt_back_merge(q, rq, bio); | |
281 | break; | |
282 | case ELEVATOR_FRONT_MERGE: | |
283 | if (blk_mq_sched_allow_merge(q, rq, bio)) | |
284 | merged = bio_attempt_front_merge(q, rq, bio); | |
285 | break; | |
286 | case ELEVATOR_DISCARD_MERGE: | |
287 | merged = bio_attempt_discard_merge(q, rq, bio); | |
288 | break; | |
289 | default: | |
290 | continue; | |
291 | } | |
292 | ||
9bddeb2a ML |
293 | return merged; |
294 | } | |
295 | ||
296 | return false; | |
297 | } | |
9c558734 JA |
298 | EXPORT_SYMBOL_GPL(blk_mq_bio_list_merge); |
299 | ||
300 | /* | |
301 | * Reverse check our software queue for entries that we could potentially | |
302 | * merge with. Currently includes a hand-wavy stop count of 8, to not spend | |
303 | * too much time checking for merges. | |
304 | */ | |
305 | static bool blk_mq_attempt_merge(struct request_queue *q, | |
c16d6b5a | 306 | struct blk_mq_hw_ctx *hctx, |
9c558734 JA |
307 | struct blk_mq_ctx *ctx, struct bio *bio) |
308 | { | |
c16d6b5a ML |
309 | enum hctx_type type = hctx->type; |
310 | ||
9c558734 JA |
311 | lockdep_assert_held(&ctx->lock); |
312 | ||
c16d6b5a | 313 | if (blk_mq_bio_list_merge(q, &ctx->rq_lists[type], bio)) { |
9c558734 JA |
314 | ctx->rq_merged++; |
315 | return true; | |
316 | } | |
317 | ||
318 | return false; | |
319 | } | |
9bddeb2a | 320 | |
bd166ef1 JA |
321 | bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) |
322 | { | |
323 | struct elevator_queue *e = q->elevator; | |
9bddeb2a | 324 | struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); |
8ccdf4a3 | 325 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, bio->bi_opf, ctx); |
9bddeb2a | 326 | bool ret = false; |
c16d6b5a | 327 | enum hctx_type type; |
bd166ef1 | 328 | |
f9cd4bfe | 329 | if (e && e->type->ops.bio_merge) { |
bd166ef1 | 330 | blk_mq_put_ctx(ctx); |
f9cd4bfe | 331 | return e->type->ops.bio_merge(hctx, bio); |
bd166ef1 JA |
332 | } |
333 | ||
c16d6b5a | 334 | type = hctx->type; |
b04f50ab | 335 | if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) && |
c16d6b5a | 336 | !list_empty_careful(&ctx->rq_lists[type])) { |
9bddeb2a ML |
337 | /* default per sw-queue merge */ |
338 | spin_lock(&ctx->lock); | |
c16d6b5a | 339 | ret = blk_mq_attempt_merge(q, hctx, ctx, bio); |
9bddeb2a ML |
340 | spin_unlock(&ctx->lock); |
341 | } | |
342 | ||
343 | blk_mq_put_ctx(ctx); | |
344 | return ret; | |
bd166ef1 JA |
345 | } |
346 | ||
347 | bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq) | |
348 | { | |
349 | return rq_mergeable(rq) && elv_attempt_insert_merge(q, rq); | |
350 | } | |
351 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_insert_merge); | |
352 | ||
353 | void blk_mq_sched_request_inserted(struct request *rq) | |
354 | { | |
355 | trace_block_rq_insert(rq->q, rq); | |
356 | } | |
357 | EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted); | |
358 | ||
0cacba6c | 359 | static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx, |
a6a252e6 | 360 | bool has_sched, |
0cacba6c | 361 | struct request *rq) |
bd166ef1 | 362 | { |
a6a252e6 ML |
363 | /* dispatch flush rq directly */ |
364 | if (rq->rq_flags & RQF_FLUSH_SEQ) { | |
365 | spin_lock(&hctx->lock); | |
366 | list_add(&rq->queuelist, &hctx->dispatch); | |
367 | spin_unlock(&hctx->lock); | |
368 | return true; | |
369 | } | |
370 | ||
923218f6 | 371 | if (has_sched) |
bd166ef1 | 372 | rq->rq_flags |= RQF_SORTED; |
bd166ef1 | 373 | |
a6a252e6 | 374 | return false; |
bd166ef1 | 375 | } |
bd166ef1 | 376 | |
bd6737f1 | 377 | void blk_mq_sched_insert_request(struct request *rq, bool at_head, |
9e97d295 | 378 | bool run_queue, bool async) |
bd6737f1 JA |
379 | { |
380 | struct request_queue *q = rq->q; | |
381 | struct elevator_queue *e = q->elevator; | |
382 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
ea4f995e | 383 | struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
bd6737f1 | 384 | |
a6a252e6 ML |
385 | /* flush rq in flush machinery need to be dispatched directly */ |
386 | if (!(rq->rq_flags & RQF_FLUSH_SEQ) && op_is_flush(rq->cmd_flags)) { | |
923218f6 ML |
387 | blk_insert_flush(rq); |
388 | goto run; | |
bd6737f1 JA |
389 | } |
390 | ||
923218f6 ML |
391 | WARN_ON(e && (rq->tag != -1)); |
392 | ||
a6a252e6 | 393 | if (blk_mq_sched_bypass_insert(hctx, !!e, rq)) |
0cacba6c OS |
394 | goto run; |
395 | ||
f9cd4bfe | 396 | if (e && e->type->ops.insert_requests) { |
bd6737f1 JA |
397 | LIST_HEAD(list); |
398 | ||
399 | list_add(&rq->queuelist, &list); | |
f9cd4bfe | 400 | e->type->ops.insert_requests(hctx, &list, at_head); |
bd6737f1 JA |
401 | } else { |
402 | spin_lock(&ctx->lock); | |
403 | __blk_mq_insert_request(hctx, rq, at_head); | |
404 | spin_unlock(&ctx->lock); | |
405 | } | |
406 | ||
0cacba6c | 407 | run: |
bd6737f1 JA |
408 | if (run_queue) |
409 | blk_mq_run_hw_queue(hctx, async); | |
410 | } | |
411 | ||
67cae4c9 | 412 | void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx, |
bd6737f1 JA |
413 | struct blk_mq_ctx *ctx, |
414 | struct list_head *list, bool run_queue_async) | |
415 | { | |
f9afca4d | 416 | struct elevator_queue *e; |
e87eb301 ML |
417 | struct request_queue *q = hctx->queue; |
418 | ||
419 | /* | |
420 | * blk_mq_sched_insert_requests() is called from flush plug | |
421 | * context only, and hold one usage counter to prevent queue | |
422 | * from being released. | |
423 | */ | |
424 | percpu_ref_get(&q->q_usage_counter); | |
bd6737f1 | 425 | |
f9afca4d | 426 | e = hctx->queue->elevator; |
f9cd4bfe JA |
427 | if (e && e->type->ops.insert_requests) |
428 | e->type->ops.insert_requests(hctx, list, false); | |
6ce3dd6e ML |
429 | else { |
430 | /* | |
431 | * try to issue requests directly if the hw queue isn't | |
432 | * busy in case of 'none' scheduler, and this way may save | |
433 | * us one extra enqueue & dequeue to sw queue. | |
434 | */ | |
fd9c40f6 | 435 | if (!hctx->dispatch_busy && !e && !run_queue_async) { |
6ce3dd6e | 436 | blk_mq_try_issue_list_directly(hctx, list); |
fd9c40f6 | 437 | if (list_empty(list)) |
e87eb301 | 438 | goto out; |
fd9c40f6 BVA |
439 | } |
440 | blk_mq_insert_requests(hctx, ctx, list); | |
6ce3dd6e | 441 | } |
bd6737f1 JA |
442 | |
443 | blk_mq_run_hw_queue(hctx, run_queue_async); | |
e87eb301 ML |
444 | out: |
445 | percpu_ref_put(&q->q_usage_counter); | |
bd6737f1 JA |
446 | } |
447 | ||
bd166ef1 JA |
448 | static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, |
449 | struct blk_mq_hw_ctx *hctx, | |
450 | unsigned int hctx_idx) | |
451 | { | |
452 | if (hctx->sched_tags) { | |
453 | blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx); | |
454 | blk_mq_free_rq_map(hctx->sched_tags); | |
455 | hctx->sched_tags = NULL; | |
456 | } | |
457 | } | |
458 | ||
6917ff0b OS |
459 | static int blk_mq_sched_alloc_tags(struct request_queue *q, |
460 | struct blk_mq_hw_ctx *hctx, | |
461 | unsigned int hctx_idx) | |
462 | { | |
463 | struct blk_mq_tag_set *set = q->tag_set; | |
464 | int ret; | |
465 | ||
466 | hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests, | |
467 | set->reserved_tags); | |
468 | if (!hctx->sched_tags) | |
469 | return -ENOMEM; | |
470 | ||
471 | ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests); | |
472 | if (ret) | |
473 | blk_mq_sched_free_tags(set, hctx, hctx_idx); | |
474 | ||
475 | return ret; | |
476 | } | |
477 | ||
54d5329d | 478 | static void blk_mq_sched_tags_teardown(struct request_queue *q) |
bd166ef1 JA |
479 | { |
480 | struct blk_mq_tag_set *set = q->tag_set; | |
481 | struct blk_mq_hw_ctx *hctx; | |
6917ff0b OS |
482 | int i; |
483 | ||
484 | queue_for_each_hw_ctx(q, hctx, i) | |
485 | blk_mq_sched_free_tags(set, hctx, i); | |
486 | } | |
487 | ||
488 | int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e) | |
489 | { | |
490 | struct blk_mq_hw_ctx *hctx; | |
ee056f98 | 491 | struct elevator_queue *eq; |
6917ff0b OS |
492 | unsigned int i; |
493 | int ret; | |
494 | ||
495 | if (!e) { | |
496 | q->elevator = NULL; | |
32a50fab | 497 | q->nr_requests = q->tag_set->queue_depth; |
6917ff0b OS |
498 | return 0; |
499 | } | |
bd166ef1 JA |
500 | |
501 | /* | |
32825c45 ML |
502 | * Default to double of smaller one between hw queue_depth and 128, |
503 | * since we don't split into sync/async like the old code did. | |
504 | * Additionally, this is a per-hw queue depth. | |
bd166ef1 | 505 | */ |
32825c45 ML |
506 | q->nr_requests = 2 * min_t(unsigned int, q->tag_set->queue_depth, |
507 | BLKDEV_MAX_RQ); | |
bd166ef1 | 508 | |
bd166ef1 | 509 | queue_for_each_hw_ctx(q, hctx, i) { |
6917ff0b | 510 | ret = blk_mq_sched_alloc_tags(q, hctx, i); |
bd166ef1 | 511 | if (ret) |
6917ff0b | 512 | goto err; |
bd166ef1 JA |
513 | } |
514 | ||
f9cd4bfe | 515 | ret = e->ops.init_sched(q, e); |
6917ff0b OS |
516 | if (ret) |
517 | goto err; | |
bd166ef1 | 518 | |
d332ce09 OS |
519 | blk_mq_debugfs_register_sched(q); |
520 | ||
521 | queue_for_each_hw_ctx(q, hctx, i) { | |
f9cd4bfe JA |
522 | if (e->ops.init_hctx) { |
523 | ret = e->ops.init_hctx(hctx, i); | |
ee056f98 OS |
524 | if (ret) { |
525 | eq = q->elevator; | |
526 | blk_mq_exit_sched(q, eq); | |
527 | kobject_put(&eq->kobj); | |
528 | return ret; | |
529 | } | |
530 | } | |
d332ce09 | 531 | blk_mq_debugfs_register_sched_hctx(q, hctx); |
ee056f98 OS |
532 | } |
533 | ||
bd166ef1 | 534 | return 0; |
bd166ef1 | 535 | |
6917ff0b | 536 | err: |
54d5329d OS |
537 | blk_mq_sched_tags_teardown(q); |
538 | q->elevator = NULL; | |
6917ff0b | 539 | return ret; |
bd166ef1 | 540 | } |
d3484991 | 541 | |
54d5329d OS |
542 | void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e) |
543 | { | |
ee056f98 OS |
544 | struct blk_mq_hw_ctx *hctx; |
545 | unsigned int i; | |
546 | ||
d332ce09 OS |
547 | queue_for_each_hw_ctx(q, hctx, i) { |
548 | blk_mq_debugfs_unregister_sched_hctx(hctx); | |
f9cd4bfe JA |
549 | if (e->type->ops.exit_hctx && hctx->sched_data) { |
550 | e->type->ops.exit_hctx(hctx, i); | |
d332ce09 | 551 | hctx->sched_data = NULL; |
ee056f98 OS |
552 | } |
553 | } | |
d332ce09 | 554 | blk_mq_debugfs_unregister_sched(q); |
f9cd4bfe JA |
555 | if (e->type->ops.exit_sched) |
556 | e->type->ops.exit_sched(e); | |
54d5329d OS |
557 | blk_mq_sched_tags_teardown(q); |
558 | q->elevator = NULL; | |
559 | } |