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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" | |
14 | #include "blk-mq-debugfs.h" | |
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 | ||
34 | void blk_mq_sched_assign_ioc(struct request *rq, struct bio *bio) | |
35 | { | |
36 | struct request_queue *q = rq->q; | |
37 | struct io_context *ioc = rq_ioc(bio); | |
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 | } | |
49 | get_io_context(icq->ioc); | |
50 | rq->elv.icq = icq; | |
51 | } | |
52 | ||
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 | ||
62 | if (hctx->flags & BLK_MQ_F_TAG_SHARED) { | |
63 | struct request_queue *q = hctx->queue; | |
64 | ||
65 | if (!test_and_set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) | |
66 | atomic_inc(&q->shared_hctx_restart); | |
67 | } else | |
68 | set_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); | |
69 | } | |
70 | ||
71 | static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx) | |
72 | { | |
73 | if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) | |
74 | return false; | |
75 | ||
76 | if (hctx->flags & BLK_MQ_F_TAG_SHARED) { | |
77 | struct request_queue *q = hctx->queue; | |
78 | ||
79 | if (test_and_clear_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) | |
80 | atomic_dec(&q->shared_hctx_restart); | |
81 | } else | |
82 | clear_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state); | |
83 | ||
84 | return blk_mq_run_hw_queue(hctx, true); | |
85 | } | |
86 | ||
87 | /* | |
88 | * Only SCSI implements .get_budget and .put_budget, and SCSI restarts | |
89 | * its queue by itself in its completion handler, so we don't need to | |
90 | * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE. | |
91 | */ | |
92 | static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) | |
93 | { | |
94 | struct request_queue *q = hctx->queue; | |
95 | struct elevator_queue *e = q->elevator; | |
96 | LIST_HEAD(rq_list); | |
97 | ||
98 | do { | |
99 | struct request *rq; | |
100 | ||
101 | if (e->type->ops.mq.has_work && | |
102 | !e->type->ops.mq.has_work(hctx)) | |
103 | break; | |
104 | ||
105 | if (!blk_mq_get_dispatch_budget(hctx)) | |
106 | break; | |
107 | ||
108 | rq = e->type->ops.mq.dispatch_request(hctx); | |
109 | if (!rq) { | |
110 | blk_mq_put_dispatch_budget(hctx); | |
111 | break; | |
112 | } | |
113 | ||
114 | /* | |
115 | * Now this rq owns the budget which has to be released | |
116 | * if this rq won't be queued to driver via .queue_rq() | |
117 | * in blk_mq_dispatch_rq_list(). | |
118 | */ | |
119 | list_add(&rq->queuelist, &rq_list); | |
120 | } while (blk_mq_dispatch_rq_list(q, &rq_list, true)); | |
121 | } | |
122 | ||
123 | static struct blk_mq_ctx *blk_mq_next_ctx(struct blk_mq_hw_ctx *hctx, | |
124 | struct blk_mq_ctx *ctx) | |
125 | { | |
126 | unsigned idx = ctx->index_hw; | |
127 | ||
128 | if (++idx == hctx->nr_ctx) | |
129 | idx = 0; | |
130 | ||
131 | return hctx->ctxs[idx]; | |
132 | } | |
133 | ||
134 | /* | |
135 | * Only SCSI implements .get_budget and .put_budget, and SCSI restarts | |
136 | * its queue by itself in its completion handler, so we don't need to | |
137 | * restart queue if .get_budget() returns BLK_STS_NO_RESOURCE. | |
138 | */ | |
139 | static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx) | |
140 | { | |
141 | struct request_queue *q = hctx->queue; | |
142 | LIST_HEAD(rq_list); | |
143 | struct blk_mq_ctx *ctx = READ_ONCE(hctx->dispatch_from); | |
144 | ||
145 | do { | |
146 | struct request *rq; | |
147 | ||
148 | if (!sbitmap_any_bit_set(&hctx->ctx_map)) | |
149 | break; | |
150 | ||
151 | if (!blk_mq_get_dispatch_budget(hctx)) | |
152 | break; | |
153 | ||
154 | rq = blk_mq_dequeue_from_ctx(hctx, ctx); | |
155 | if (!rq) { | |
156 | blk_mq_put_dispatch_budget(hctx); | |
157 | break; | |
158 | } | |
159 | ||
160 | /* | |
161 | * Now this rq owns the budget which has to be released | |
162 | * if this rq won't be queued to driver via .queue_rq() | |
163 | * in blk_mq_dispatch_rq_list(). | |
164 | */ | |
165 | list_add(&rq->queuelist, &rq_list); | |
166 | ||
167 | /* round robin for fair dispatch */ | |
168 | ctx = blk_mq_next_ctx(hctx, rq->mq_ctx); | |
169 | ||
170 | } while (blk_mq_dispatch_rq_list(q, &rq_list, true)); | |
171 | ||
172 | WRITE_ONCE(hctx->dispatch_from, ctx); | |
173 | } | |
174 | ||
175 | /* return true if hw queue need to be run again */ | |
176 | void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx) | |
177 | { | |
178 | struct request_queue *q = hctx->queue; | |
179 | struct elevator_queue *e = q->elevator; | |
180 | const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request; | |
181 | LIST_HEAD(rq_list); | |
182 | ||
183 | /* RCU or SRCU read lock is needed before checking quiesced flag */ | |
184 | if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q))) | |
185 | return; | |
186 | ||
187 | hctx->run++; | |
188 | ||
189 | /* | |
190 | * If we have previous entries on our dispatch list, grab them first for | |
191 | * more fair dispatch. | |
192 | */ | |
193 | if (!list_empty_careful(&hctx->dispatch)) { | |
194 | spin_lock(&hctx->lock); | |
195 | if (!list_empty(&hctx->dispatch)) | |
196 | list_splice_init(&hctx->dispatch, &rq_list); | |
197 | spin_unlock(&hctx->lock); | |
198 | } | |
199 | ||
200 | /* | |
201 | * Only ask the scheduler for requests, if we didn't have residual | |
202 | * requests from the dispatch list. This is to avoid the case where | |
203 | * we only ever dispatch a fraction of the requests available because | |
204 | * of low device queue depth. Once we pull requests out of the IO | |
205 | * scheduler, we can no longer merge or sort them. So it's best to | |
206 | * leave them there for as long as we can. Mark the hw queue as | |
207 | * needing a restart in that case. | |
208 | * | |
209 | * We want to dispatch from the scheduler if there was nothing | |
210 | * on the dispatch list or we were able to dispatch from the | |
211 | * dispatch list. | |
212 | */ | |
213 | if (!list_empty(&rq_list)) { | |
214 | blk_mq_sched_mark_restart_hctx(hctx); | |
215 | if (blk_mq_dispatch_rq_list(q, &rq_list, false)) { | |
216 | if (has_sched_dispatch) | |
217 | blk_mq_do_dispatch_sched(hctx); | |
218 | else | |
219 | blk_mq_do_dispatch_ctx(hctx); | |
220 | } | |
221 | } else if (has_sched_dispatch) { | |
222 | blk_mq_do_dispatch_sched(hctx); | |
223 | } else if (q->mq_ops->get_budget) { | |
224 | /* | |
225 | * If we need to get budget before queuing request, we | |
226 | * dequeue request one by one from sw queue for avoiding | |
227 | * to mess up I/O merge when dispatch runs out of resource. | |
228 | * | |
229 | * TODO: get more budgets, and dequeue more requests in | |
230 | * one time. | |
231 | */ | |
232 | blk_mq_do_dispatch_ctx(hctx); | |
233 | } else { | |
234 | blk_mq_flush_busy_ctxs(hctx, &rq_list); | |
235 | blk_mq_dispatch_rq_list(q, &rq_list, false); | |
236 | } | |
237 | } | |
238 | ||
239 | bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, | |
240 | struct request **merged_request) | |
241 | { | |
242 | struct request *rq; | |
243 | ||
244 | switch (elv_merge(q, &rq, bio)) { | |
245 | case ELEVATOR_BACK_MERGE: | |
246 | if (!blk_mq_sched_allow_merge(q, rq, bio)) | |
247 | return false; | |
248 | if (!bio_attempt_back_merge(q, rq, bio)) | |
249 | return false; | |
250 | *merged_request = attempt_back_merge(q, rq); | |
251 | if (!*merged_request) | |
252 | elv_merged_request(q, rq, ELEVATOR_BACK_MERGE); | |
253 | return true; | |
254 | case ELEVATOR_FRONT_MERGE: | |
255 | if (!blk_mq_sched_allow_merge(q, rq, bio)) | |
256 | return false; | |
257 | if (!bio_attempt_front_merge(q, rq, bio)) | |
258 | return false; | |
259 | *merged_request = attempt_front_merge(q, rq); | |
260 | if (!*merged_request) | |
261 | elv_merged_request(q, rq, ELEVATOR_FRONT_MERGE); | |
262 | return true; | |
263 | default: | |
264 | return false; | |
265 | } | |
266 | } | |
267 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); | |
268 | ||
269 | /* | |
270 | * Reverse check our software queue for entries that we could potentially | |
271 | * merge with. Currently includes a hand-wavy stop count of 8, to not spend | |
272 | * too much time checking for merges. | |
273 | */ | |
274 | static bool blk_mq_attempt_merge(struct request_queue *q, | |
275 | struct blk_mq_ctx *ctx, struct bio *bio) | |
276 | { | |
277 | struct request *rq; | |
278 | int checked = 8; | |
279 | ||
280 | lockdep_assert_held(&ctx->lock); | |
281 | ||
282 | list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { | |
283 | bool merged = false; | |
284 | ||
285 | if (!checked--) | |
286 | break; | |
287 | ||
288 | if (!blk_rq_merge_ok(rq, bio)) | |
289 | continue; | |
290 | ||
291 | switch (blk_try_merge(rq, bio)) { | |
292 | case ELEVATOR_BACK_MERGE: | |
293 | if (blk_mq_sched_allow_merge(q, rq, bio)) | |
294 | merged = bio_attempt_back_merge(q, rq, bio); | |
295 | break; | |
296 | case ELEVATOR_FRONT_MERGE: | |
297 | if (blk_mq_sched_allow_merge(q, rq, bio)) | |
298 | merged = bio_attempt_front_merge(q, rq, bio); | |
299 | break; | |
300 | case ELEVATOR_DISCARD_MERGE: | |
301 | merged = bio_attempt_discard_merge(q, rq, bio); | |
302 | break; | |
303 | default: | |
304 | continue; | |
305 | } | |
306 | ||
307 | if (merged) | |
308 | ctx->rq_merged++; | |
309 | return merged; | |
310 | } | |
311 | ||
312 | return false; | |
313 | } | |
314 | ||
315 | bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) | |
316 | { | |
317 | struct elevator_queue *e = q->elevator; | |
318 | struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); | |
319 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); | |
320 | bool ret = false; | |
321 | ||
322 | if (e && e->type->ops.mq.bio_merge) { | |
323 | blk_mq_put_ctx(ctx); | |
324 | return e->type->ops.mq.bio_merge(hctx, bio); | |
325 | } | |
326 | ||
327 | if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) && | |
328 | !list_empty_careful(&ctx->rq_list)) { | |
329 | /* default per sw-queue merge */ | |
330 | spin_lock(&ctx->lock); | |
331 | ret = blk_mq_attempt_merge(q, ctx, bio); | |
332 | spin_unlock(&ctx->lock); | |
333 | } | |
334 | ||
335 | blk_mq_put_ctx(ctx); | |
336 | return ret; | |
337 | } | |
338 | ||
339 | bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq) | |
340 | { | |
341 | return rq_mergeable(rq) && elv_attempt_insert_merge(q, rq); | |
342 | } | |
343 | EXPORT_SYMBOL_GPL(blk_mq_sched_try_insert_merge); | |
344 | ||
345 | void blk_mq_sched_request_inserted(struct request *rq) | |
346 | { | |
347 | trace_block_rq_insert(rq->q, rq); | |
348 | } | |
349 | EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted); | |
350 | ||
351 | static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx, | |
352 | bool has_sched, | |
353 | struct request *rq) | |
354 | { | |
355 | /* dispatch flush rq directly */ | |
356 | if (rq->rq_flags & RQF_FLUSH_SEQ) { | |
357 | spin_lock(&hctx->lock); | |
358 | list_add(&rq->queuelist, &hctx->dispatch); | |
359 | spin_unlock(&hctx->lock); | |
360 | return true; | |
361 | } | |
362 | ||
363 | if (has_sched) | |
364 | rq->rq_flags |= RQF_SORTED; | |
365 | ||
366 | return false; | |
367 | } | |
368 | ||
369 | /** | |
370 | * list_for_each_entry_rcu_rr - iterate in a round-robin fashion over rcu list | |
371 | * @pos: loop cursor. | |
372 | * @skip: the list element that will not be examined. Iteration starts at | |
373 | * @skip->next. | |
374 | * @head: head of the list to examine. This list must have at least one | |
375 | * element, namely @skip. | |
376 | * @member: name of the list_head structure within typeof(*pos). | |
377 | */ | |
378 | #define list_for_each_entry_rcu_rr(pos, skip, head, member) \ | |
379 | for ((pos) = (skip); \ | |
380 | (pos = (pos)->member.next != (head) ? list_entry_rcu( \ | |
381 | (pos)->member.next, typeof(*pos), member) : \ | |
382 | list_entry_rcu((pos)->member.next->next, typeof(*pos), member)), \ | |
383 | (pos) != (skip); ) | |
384 | ||
385 | /* | |
386 | * Called after a driver tag has been freed to check whether a hctx needs to | |
387 | * be restarted. Restarts @hctx if its tag set is not shared. Restarts hardware | |
388 | * queues in a round-robin fashion if the tag set of @hctx is shared with other | |
389 | * hardware queues. | |
390 | */ | |
391 | void blk_mq_sched_restart(struct blk_mq_hw_ctx *const hctx) | |
392 | { | |
393 | struct blk_mq_tags *const tags = hctx->tags; | |
394 | struct blk_mq_tag_set *const set = hctx->queue->tag_set; | |
395 | struct request_queue *const queue = hctx->queue, *q; | |
396 | struct blk_mq_hw_ctx *hctx2; | |
397 | unsigned int i, j; | |
398 | ||
399 | if (set->flags & BLK_MQ_F_TAG_SHARED) { | |
400 | /* | |
401 | * If this is 0, then we know that no hardware queues | |
402 | * have RESTART marked. We're done. | |
403 | */ | |
404 | if (!atomic_read(&queue->shared_hctx_restart)) | |
405 | return; | |
406 | ||
407 | rcu_read_lock(); | |
408 | list_for_each_entry_rcu_rr(q, queue, &set->tag_list, | |
409 | tag_set_list) { | |
410 | queue_for_each_hw_ctx(q, hctx2, i) | |
411 | if (hctx2->tags == tags && | |
412 | blk_mq_sched_restart_hctx(hctx2)) | |
413 | goto done; | |
414 | } | |
415 | j = hctx->queue_num + 1; | |
416 | for (i = 0; i < queue->nr_hw_queues; i++, j++) { | |
417 | if (j == queue->nr_hw_queues) | |
418 | j = 0; | |
419 | hctx2 = queue->queue_hw_ctx[j]; | |
420 | if (hctx2->tags == tags && | |
421 | blk_mq_sched_restart_hctx(hctx2)) | |
422 | break; | |
423 | } | |
424 | done: | |
425 | rcu_read_unlock(); | |
426 | } else { | |
427 | blk_mq_sched_restart_hctx(hctx); | |
428 | } | |
429 | } | |
430 | ||
431 | void blk_mq_sched_insert_request(struct request *rq, bool at_head, | |
432 | bool run_queue, bool async, bool can_block) | |
433 | { | |
434 | struct request_queue *q = rq->q; | |
435 | struct elevator_queue *e = q->elevator; | |
436 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
437 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); | |
438 | ||
439 | /* flush rq in flush machinery need to be dispatched directly */ | |
440 | if (!(rq->rq_flags & RQF_FLUSH_SEQ) && op_is_flush(rq->cmd_flags)) { | |
441 | blk_insert_flush(rq); | |
442 | goto run; | |
443 | } | |
444 | ||
445 | WARN_ON(e && (rq->tag != -1)); | |
446 | ||
447 | if (blk_mq_sched_bypass_insert(hctx, !!e, rq)) | |
448 | goto run; | |
449 | ||
450 | if (e && e->type->ops.mq.insert_requests) { | |
451 | LIST_HEAD(list); | |
452 | ||
453 | list_add(&rq->queuelist, &list); | |
454 | e->type->ops.mq.insert_requests(hctx, &list, at_head); | |
455 | } else { | |
456 | spin_lock(&ctx->lock); | |
457 | __blk_mq_insert_request(hctx, rq, at_head); | |
458 | spin_unlock(&ctx->lock); | |
459 | } | |
460 | ||
461 | run: | |
462 | if (run_queue) | |
463 | blk_mq_run_hw_queue(hctx, async); | |
464 | } | |
465 | ||
466 | void blk_mq_sched_insert_requests(struct request_queue *q, | |
467 | struct blk_mq_ctx *ctx, | |
468 | struct list_head *list, bool run_queue_async) | |
469 | { | |
470 | struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); | |
471 | struct elevator_queue *e = hctx->queue->elevator; | |
472 | ||
473 | if (e && e->type->ops.mq.insert_requests) | |
474 | e->type->ops.mq.insert_requests(hctx, list, false); | |
475 | else | |
476 | blk_mq_insert_requests(hctx, ctx, list); | |
477 | ||
478 | blk_mq_run_hw_queue(hctx, run_queue_async); | |
479 | } | |
480 | ||
481 | static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set, | |
482 | struct blk_mq_hw_ctx *hctx, | |
483 | unsigned int hctx_idx) | |
484 | { | |
485 | if (hctx->sched_tags) { | |
486 | blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx); | |
487 | blk_mq_free_rq_map(hctx->sched_tags); | |
488 | hctx->sched_tags = NULL; | |
489 | } | |
490 | } | |
491 | ||
492 | static int blk_mq_sched_alloc_tags(struct request_queue *q, | |
493 | struct blk_mq_hw_ctx *hctx, | |
494 | unsigned int hctx_idx) | |
495 | { | |
496 | struct blk_mq_tag_set *set = q->tag_set; | |
497 | int ret; | |
498 | ||
499 | hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests, | |
500 | set->reserved_tags); | |
501 | if (!hctx->sched_tags) | |
502 | return -ENOMEM; | |
503 | ||
504 | ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests); | |
505 | if (ret) | |
506 | blk_mq_sched_free_tags(set, hctx, hctx_idx); | |
507 | ||
508 | return ret; | |
509 | } | |
510 | ||
511 | static void blk_mq_sched_tags_teardown(struct request_queue *q) | |
512 | { | |
513 | struct blk_mq_tag_set *set = q->tag_set; | |
514 | struct blk_mq_hw_ctx *hctx; | |
515 | int i; | |
516 | ||
517 | queue_for_each_hw_ctx(q, hctx, i) | |
518 | blk_mq_sched_free_tags(set, hctx, i); | |
519 | } | |
520 | ||
521 | int blk_mq_sched_init_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx, | |
522 | unsigned int hctx_idx) | |
523 | { | |
524 | struct elevator_queue *e = q->elevator; | |
525 | int ret; | |
526 | ||
527 | if (!e) | |
528 | return 0; | |
529 | ||
530 | ret = blk_mq_sched_alloc_tags(q, hctx, hctx_idx); | |
531 | if (ret) | |
532 | return ret; | |
533 | ||
534 | if (e->type->ops.mq.init_hctx) { | |
535 | ret = e->type->ops.mq.init_hctx(hctx, hctx_idx); | |
536 | if (ret) { | |
537 | blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx); | |
538 | return ret; | |
539 | } | |
540 | } | |
541 | ||
542 | blk_mq_debugfs_register_sched_hctx(q, hctx); | |
543 | ||
544 | return 0; | |
545 | } | |
546 | ||
547 | void blk_mq_sched_exit_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx, | |
548 | unsigned int hctx_idx) | |
549 | { | |
550 | struct elevator_queue *e = q->elevator; | |
551 | ||
552 | if (!e) | |
553 | return; | |
554 | ||
555 | blk_mq_debugfs_unregister_sched_hctx(hctx); | |
556 | ||
557 | if (e->type->ops.mq.exit_hctx && hctx->sched_data) { | |
558 | e->type->ops.mq.exit_hctx(hctx, hctx_idx); | |
559 | hctx->sched_data = NULL; | |
560 | } | |
561 | ||
562 | blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx); | |
563 | } | |
564 | ||
565 | int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e) | |
566 | { | |
567 | struct blk_mq_hw_ctx *hctx; | |
568 | struct elevator_queue *eq; | |
569 | unsigned int i; | |
570 | int ret; | |
571 | ||
572 | if (!e) { | |
573 | q->elevator = NULL; | |
574 | return 0; | |
575 | } | |
576 | ||
577 | /* | |
578 | * Default to double of smaller one between hw queue_depth and 128, | |
579 | * since we don't split into sync/async like the old code did. | |
580 | * Additionally, this is a per-hw queue depth. | |
581 | */ | |
582 | q->nr_requests = 2 * min_t(unsigned int, q->tag_set->queue_depth, | |
583 | BLKDEV_MAX_RQ); | |
584 | ||
585 | queue_for_each_hw_ctx(q, hctx, i) { | |
586 | ret = blk_mq_sched_alloc_tags(q, hctx, i); | |
587 | if (ret) | |
588 | goto err; | |
589 | } | |
590 | ||
591 | ret = e->ops.mq.init_sched(q, e); | |
592 | if (ret) | |
593 | goto err; | |
594 | ||
595 | blk_mq_debugfs_register_sched(q); | |
596 | ||
597 | queue_for_each_hw_ctx(q, hctx, i) { | |
598 | if (e->ops.mq.init_hctx) { | |
599 | ret = e->ops.mq.init_hctx(hctx, i); | |
600 | if (ret) { | |
601 | eq = q->elevator; | |
602 | blk_mq_exit_sched(q, eq); | |
603 | kobject_put(&eq->kobj); | |
604 | return ret; | |
605 | } | |
606 | } | |
607 | blk_mq_debugfs_register_sched_hctx(q, hctx); | |
608 | } | |
609 | ||
610 | return 0; | |
611 | ||
612 | err: | |
613 | blk_mq_sched_tags_teardown(q); | |
614 | q->elevator = NULL; | |
615 | return ret; | |
616 | } | |
617 | ||
618 | void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e) | |
619 | { | |
620 | struct blk_mq_hw_ctx *hctx; | |
621 | unsigned int i; | |
622 | ||
623 | queue_for_each_hw_ctx(q, hctx, i) { | |
624 | blk_mq_debugfs_unregister_sched_hctx(hctx); | |
625 | if (e->type->ops.mq.exit_hctx && hctx->sched_data) { | |
626 | e->type->ops.mq.exit_hctx(hctx, i); | |
627 | hctx->sched_data = NULL; | |
628 | } | |
629 | } | |
630 | blk_mq_debugfs_unregister_sched(q); | |
631 | if (e->type->ops.mq.exit_sched) | |
632 | e->type->ops.mq.exit_sched(e); | |
633 | blk_mq_sched_tags_teardown(q); | |
634 | q->elevator = NULL; | |
635 | } | |
636 | ||
637 | int blk_mq_sched_init(struct request_queue *q) | |
638 | { | |
639 | int ret; | |
640 | ||
641 | mutex_lock(&q->sysfs_lock); | |
642 | ret = elevator_init(q, NULL); | |
643 | mutex_unlock(&q->sysfs_lock); | |
644 | ||
645 | return ret; | |
646 | } |