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