blob: c117bd8fd1f6126849472300b3c294e65825a2f7 [file] [log] [blame]
Jens Axboebd166ef2017-01-17 06:03:22 -07001/*
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"
Omar Sandovald332ce02017-05-04 08:24:40 -060014#include "blk-mq-debugfs.h"
Jens Axboebd166ef2017-01-17 06:03:22 -070015#include "blk-mq-sched.h"
16#include "blk-mq-tag.h"
17#include "blk-wbt.h"
18
19void 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}
32EXPORT_SYMBOL_GPL(blk_mq_sched_free_hctx_data);
33
Christoph Hellwig44e8c2b2017-06-16 18:15:25 +020034void blk_mq_sched_assign_ioc(struct request *rq, struct bio *bio)
Jens Axboebd166ef2017-01-17 06:03:22 -070035{
Christoph Hellwig44e8c2b2017-06-16 18:15:25 +020036 struct request_queue *q = rq->q;
37 struct io_context *ioc = rq_ioc(bio);
Jens Axboebd166ef2017-01-17 06:03:22 -070038 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 }
Christoph Hellwigea511e32017-06-16 18:15:20 +020049 get_io_context(icq->ioc);
Christoph Hellwig44e8c2b2017-06-16 18:15:25 +020050 rq->elv.icq = icq;
Jens Axboebd166ef2017-01-17 06:03:22 -070051}
52
Jens Axboe8e8320c2017-06-20 17:56:13 -060053/*
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 */
57static 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
Jens Axboe05b79412017-11-08 10:38:29 -070071static bool blk_mq_sched_restart_hctx(struct blk_mq_hw_ctx *hctx)
Jens Axboe8e8320c2017-06-20 17:56:13 -060072{
73 if (!test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state))
Jens Axboe05b79412017-11-08 10:38:29 -070074 return false;
Jens Axboe8e8320c2017-06-20 17:56:13 -060075
Jens Axboe05b79412017-11-08 10:38:29 -070076 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);
Jens Axboe8e8320c2017-06-20 17:56:13 -060083
Jens Axboe79f720a2017-11-10 09:13:21 -070084 return blk_mq_run_hw_queue(hctx, true);
Jens Axboe8e8320c2017-06-20 17:56:13 -060085}
86
Ming Lei1f460b62017-10-27 12:43:30 +080087/*
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 */
92static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx)
Ming Leicaf8eb02017-10-14 17:22:26 +080093{
94 struct request_queue *q = hctx->queue;
95 struct elevator_queue *e = q->elevator;
96 LIST_HEAD(rq_list);
97
98 do {
Ming Leide148292017-10-14 17:22:29 +080099 struct request *rq;
Ming Leicaf8eb02017-10-14 17:22:26 +0800100
Ming Leide148292017-10-14 17:22:29 +0800101 if (e->type->ops.mq.has_work &&
102 !e->type->ops.mq.has_work(hctx))
Ming Leicaf8eb02017-10-14 17:22:26 +0800103 break;
Ming Leide148292017-10-14 17:22:29 +0800104
Ming Lei88022d72017-11-05 02:21:12 +0800105 if (!blk_mq_get_dispatch_budget(hctx))
Ming Lei1f460b62017-10-27 12:43:30 +0800106 break;
Ming Leide148292017-10-14 17:22:29 +0800107
108 rq = e->type->ops.mq.dispatch_request(hctx);
109 if (!rq) {
110 blk_mq_put_dispatch_budget(hctx);
111 break;
Ming Leide148292017-10-14 17:22:29 +0800112 }
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 */
Ming Leicaf8eb02017-10-14 17:22:26 +0800119 list_add(&rq->queuelist, &rq_list);
Ming Leide148292017-10-14 17:22:29 +0800120 } while (blk_mq_dispatch_rq_list(q, &rq_list, true));
Ming Leicaf8eb02017-10-14 17:22:26 +0800121}
122
Ming Leib3476892017-10-14 17:22:30 +0800123static 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
Ming Lei1f460b62017-10-27 12:43:30 +0800134/*
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 */
139static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx)
Ming Leib3476892017-10-14 17:22:30 +0800140{
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;
Ming Leib3476892017-10-14 17:22:30 +0800147
148 if (!sbitmap_any_bit_set(&hctx->ctx_map))
149 break;
150
Ming Lei88022d72017-11-05 02:21:12 +0800151 if (!blk_mq_get_dispatch_budget(hctx))
Ming Lei1f460b62017-10-27 12:43:30 +0800152 break;
Ming Leib3476892017-10-14 17:22:30 +0800153
154 rq = blk_mq_dequeue_from_ctx(hctx, ctx);
155 if (!rq) {
156 blk_mq_put_dispatch_budget(hctx);
157 break;
Ming Leib3476892017-10-14 17:22:30 +0800158 }
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);
Ming Leib3476892017-10-14 17:22:30 +0800173}
174
Ming Leide148292017-10-14 17:22:29 +0800175/* return true if hw queue need to be run again */
Ming Lei1f460b62017-10-27 12:43:30 +0800176void blk_mq_sched_dispatch_requests(struct blk_mq_hw_ctx *hctx)
Jens Axboebd166ef2017-01-17 06:03:22 -0700177{
Omar Sandoval81380ca2017-04-07 08:56:26 -0600178 struct request_queue *q = hctx->queue;
179 struct elevator_queue *e = q->elevator;
Jens Axboe64765a72017-02-17 11:39:26 -0700180 const bool has_sched_dispatch = e && e->type->ops.mq.dispatch_request;
Jens Axboebd166ef2017-01-17 06:03:22 -0700181 LIST_HEAD(rq_list);
182
Ming Leif4560ff2017-06-18 14:24:27 -0600183 /* RCU or SRCU read lock is needed before checking quiesced flag */
184 if (unlikely(blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)))
Ming Lei1f460b62017-10-27 12:43:30 +0800185 return;
Jens Axboebd166ef2017-01-17 06:03:22 -0700186
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.
Ming Leicaf8eb02017-10-14 17:22:26 +0800208 *
Ming Lei5e3d02b2017-10-14 17:22:25 +0800209 * 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.
Jens Axboe64765a72017-02-17 11:39:26 -0700212 */
Ming Leicaf8eb02017-10-14 17:22:26 +0800213 if (!list_empty(&rq_list)) {
214 blk_mq_sched_mark_restart_hctx(hctx);
Ming Leib3476892017-10-14 17:22:30 +0800215 if (blk_mq_dispatch_rq_list(q, &rq_list, false)) {
216 if (has_sched_dispatch)
Ming Lei1f460b62017-10-27 12:43:30 +0800217 blk_mq_do_dispatch_sched(hctx);
Ming Leib3476892017-10-14 17:22:30 +0800218 else
Ming Lei1f460b62017-10-27 12:43:30 +0800219 blk_mq_do_dispatch_ctx(hctx);
Ming Leib3476892017-10-14 17:22:30 +0800220 }
Ming Leicaf8eb02017-10-14 17:22:26 +0800221 } else if (has_sched_dispatch) {
Ming Lei1f460b62017-10-27 12:43:30 +0800222 blk_mq_do_dispatch_sched(hctx);
Ming Leib3476892017-10-14 17:22:30 +0800223 } 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 */
Ming Lei1f460b62017-10-27 12:43:30 +0800232 blk_mq_do_dispatch_ctx(hctx);
Ming Leicaf8eb02017-10-14 17:22:26 +0800233 } else {
234 blk_mq_flush_busy_ctxs(hctx, &rq_list);
Ming Leide148292017-10-14 17:22:29 +0800235 blk_mq_dispatch_rq_list(q, &rq_list, false);
Jens Axboec13660a2017-01-26 12:40:07 -0700236 }
Jens Axboebd166ef2017-01-17 06:03:22 -0700237}
238
Jens Axboee4d750c2017-02-03 09:48:28 -0700239bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio,
240 struct request **merged_request)
Jens Axboebd166ef2017-01-17 06:03:22 -0700241{
242 struct request *rq;
Jens Axboebd166ef2017-01-17 06:03:22 -0700243
Christoph Hellwig34fe7c02017-02-08 14:46:48 +0100244 switch (elv_merge(q, &rq, bio)) {
245 case ELEVATOR_BACK_MERGE:
Jens Axboebd166ef2017-01-17 06:03:22 -0700246 if (!blk_mq_sched_allow_merge(q, rq, bio))
247 return false;
Christoph Hellwig34fe7c02017-02-08 14:46:48 +0100248 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:
Jens Axboebd166ef2017-01-17 06:03:22 -0700255 if (!blk_mq_sched_allow_merge(q, rq, bio))
256 return false;
Christoph Hellwig34fe7c02017-02-08 14:46:48 +0100257 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;
Jens Axboebd166ef2017-01-17 06:03:22 -0700265 }
Jens Axboebd166ef2017-01-17 06:03:22 -0700266}
267EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge);
268
Ming Lei9bddeb22017-05-26 19:53:20 +0800269/*
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 */
274static 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
Bart Van Assche7b607812017-06-20 11:15:47 -0700280 lockdep_assert_held(&ctx->lock);
281
Ming Lei9bddeb22017-05-26 19:53:20 +0800282 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
Jens Axboebd166ef2017-01-17 06:03:22 -0700315bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio)
316{
317 struct elevator_queue *e = q->elevator;
Ming Lei9bddeb22017-05-26 19:53:20 +0800318 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;
Jens Axboebd166ef2017-01-17 06:03:22 -0700321
Ming Lei9bddeb22017-05-26 19:53:20 +0800322 if (e && e->type->ops.mq.bio_merge) {
Jens Axboebd166ef2017-01-17 06:03:22 -0700323 blk_mq_put_ctx(ctx);
324 return e->type->ops.mq.bio_merge(hctx, bio);
325 }
326
Ming Lei9bddeb22017-05-26 19:53:20 +0800327 if (hctx->flags & BLK_MQ_F_SHOULD_MERGE) {
328 /* default per sw-queue merge */
329 spin_lock(&ctx->lock);
330 ret = blk_mq_attempt_merge(q, ctx, bio);
331 spin_unlock(&ctx->lock);
332 }
333
334 blk_mq_put_ctx(ctx);
335 return ret;
Jens Axboebd166ef2017-01-17 06:03:22 -0700336}
337
338bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq)
339{
340 return rq_mergeable(rq) && elv_attempt_insert_merge(q, rq);
341}
342EXPORT_SYMBOL_GPL(blk_mq_sched_try_insert_merge);
343
344void blk_mq_sched_request_inserted(struct request *rq)
345{
346 trace_block_rq_insert(rq->q, rq);
347}
348EXPORT_SYMBOL_GPL(blk_mq_sched_request_inserted);
349
Omar Sandoval0cacba62017-02-02 15:42:39 -0800350static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx,
Ming Leia6a252e2017-11-02 23:24:36 +0800351 bool has_sched,
Omar Sandoval0cacba62017-02-02 15:42:39 -0800352 struct request *rq)
Jens Axboebd166ef2017-01-17 06:03:22 -0700353{
Ming Leia6a252e2017-11-02 23:24:36 +0800354 /* dispatch flush rq directly */
355 if (rq->rq_flags & RQF_FLUSH_SEQ) {
356 spin_lock(&hctx->lock);
357 list_add(&rq->queuelist, &hctx->dispatch);
358 spin_unlock(&hctx->lock);
359 return true;
Jens Axboebd166ef2017-01-17 06:03:22 -0700360 }
361
Ming Lei923218f2017-11-02 23:24:38 +0800362 if (has_sched)
Ming Leia6a252e2017-11-02 23:24:36 +0800363 rq->rq_flags |= RQF_SORTED;
Ming Leia6a252e2017-11-02 23:24:36 +0800364
365 return false;
Jens Axboebd166ef2017-01-17 06:03:22 -0700366}
Jens Axboebd166ef2017-01-17 06:03:22 -0700367
Jens Axboe05b79412017-11-08 10:38:29 -0700368/**
369 * list_for_each_entry_rcu_rr - iterate in a round-robin fashion over rcu list
370 * @pos: loop cursor.
371 * @skip: the list element that will not be examined. Iteration starts at
372 * @skip->next.
373 * @head: head of the list to examine. This list must have at least one
374 * element, namely @skip.
375 * @member: name of the list_head structure within typeof(*pos).
376 */
377#define list_for_each_entry_rcu_rr(pos, skip, head, member) \
378 for ((pos) = (skip); \
379 (pos = (pos)->member.next != (head) ? list_entry_rcu( \
380 (pos)->member.next, typeof(*pos), member) : \
381 list_entry_rcu((pos)->member.next->next, typeof(*pos), member)), \
382 (pos) != (skip); )
383
384/*
385 * Called after a driver tag has been freed to check whether a hctx needs to
386 * be restarted. Restarts @hctx if its tag set is not shared. Restarts hardware
387 * queues in a round-robin fashion if the tag set of @hctx is shared with other
388 * hardware queues.
389 */
390void blk_mq_sched_restart(struct blk_mq_hw_ctx *const hctx)
391{
392 struct blk_mq_tags *const tags = hctx->tags;
393 struct blk_mq_tag_set *const set = hctx->queue->tag_set;
394 struct request_queue *const queue = hctx->queue, *q;
395 struct blk_mq_hw_ctx *hctx2;
396 unsigned int i, j;
397
398 if (set->flags & BLK_MQ_F_TAG_SHARED) {
399 /*
400 * If this is 0, then we know that no hardware queues
401 * have RESTART marked. We're done.
402 */
403 if (!atomic_read(&queue->shared_hctx_restart))
404 return;
405
406 rcu_read_lock();
407 list_for_each_entry_rcu_rr(q, queue, &set->tag_list,
408 tag_set_list) {
409 queue_for_each_hw_ctx(q, hctx2, i)
410 if (hctx2->tags == tags &&
411 blk_mq_sched_restart_hctx(hctx2))
412 goto done;
413 }
414 j = hctx->queue_num + 1;
415 for (i = 0; i < queue->nr_hw_queues; i++, j++) {
416 if (j == queue->nr_hw_queues)
417 j = 0;
418 hctx2 = queue->queue_hw_ctx[j];
419 if (hctx2->tags == tags &&
420 blk_mq_sched_restart_hctx(hctx2))
421 break;
422 }
423done:
424 rcu_read_unlock();
425 } else {
426 blk_mq_sched_restart_hctx(hctx);
427 }
428}
429
Jens Axboebd6737f2017-01-27 01:00:47 -0700430void blk_mq_sched_insert_request(struct request *rq, bool at_head,
431 bool run_queue, bool async, bool can_block)
432{
433 struct request_queue *q = rq->q;
434 struct elevator_queue *e = q->elevator;
435 struct blk_mq_ctx *ctx = rq->mq_ctx;
436 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
437
Ming Leia6a252e2017-11-02 23:24:36 +0800438 /* flush rq in flush machinery need to be dispatched directly */
439 if (!(rq->rq_flags & RQF_FLUSH_SEQ) && op_is_flush(rq->cmd_flags)) {
Ming Lei923218f2017-11-02 23:24:38 +0800440 blk_insert_flush(rq);
441 goto run;
Jens Axboebd6737f2017-01-27 01:00:47 -0700442 }
443
Ming Lei923218f2017-11-02 23:24:38 +0800444 WARN_ON(e && (rq->tag != -1));
445
Ming Leia6a252e2017-11-02 23:24:36 +0800446 if (blk_mq_sched_bypass_insert(hctx, !!e, rq))
Omar Sandoval0cacba62017-02-02 15:42:39 -0800447 goto run;
448
Jens Axboebd6737f2017-01-27 01:00:47 -0700449 if (e && e->type->ops.mq.insert_requests) {
450 LIST_HEAD(list);
451
452 list_add(&rq->queuelist, &list);
453 e->type->ops.mq.insert_requests(hctx, &list, at_head);
454 } else {
455 spin_lock(&ctx->lock);
456 __blk_mq_insert_request(hctx, rq, at_head);
457 spin_unlock(&ctx->lock);
458 }
459
Omar Sandoval0cacba62017-02-02 15:42:39 -0800460run:
Jens Axboebd6737f2017-01-27 01:00:47 -0700461 if (run_queue)
462 blk_mq_run_hw_queue(hctx, async);
463}
464
465void blk_mq_sched_insert_requests(struct request_queue *q,
466 struct blk_mq_ctx *ctx,
467 struct list_head *list, bool run_queue_async)
468{
469 struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu);
470 struct elevator_queue *e = hctx->queue->elevator;
471
472 if (e && e->type->ops.mq.insert_requests)
473 e->type->ops.mq.insert_requests(hctx, list, false);
474 else
475 blk_mq_insert_requests(hctx, ctx, list);
476
477 blk_mq_run_hw_queue(hctx, run_queue_async);
478}
479
Jens Axboebd166ef2017-01-17 06:03:22 -0700480static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
481 struct blk_mq_hw_ctx *hctx,
482 unsigned int hctx_idx)
483{
484 if (hctx->sched_tags) {
485 blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx);
486 blk_mq_free_rq_map(hctx->sched_tags);
487 hctx->sched_tags = NULL;
488 }
489}
490
Omar Sandoval6917ff02017-04-05 12:01:30 -0700491static int blk_mq_sched_alloc_tags(struct request_queue *q,
492 struct blk_mq_hw_ctx *hctx,
493 unsigned int hctx_idx)
Jens Axboebd166ef2017-01-17 06:03:22 -0700494{
495 struct blk_mq_tag_set *set = q->tag_set;
Omar Sandoval6917ff02017-04-05 12:01:30 -0700496 int ret;
Jens Axboebd166ef2017-01-17 06:03:22 -0700497
Omar Sandoval6917ff02017-04-05 12:01:30 -0700498 hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests,
499 set->reserved_tags);
500 if (!hctx->sched_tags)
501 return -ENOMEM;
Jens Axboebd166ef2017-01-17 06:03:22 -0700502
Omar Sandoval6917ff02017-04-05 12:01:30 -0700503 ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);
504 if (ret)
505 blk_mq_sched_free_tags(set, hctx, hctx_idx);
Jens Axboebd166ef2017-01-17 06:03:22 -0700506
Omar Sandoval6917ff02017-04-05 12:01:30 -0700507 return ret;
Jens Axboebd166ef2017-01-17 06:03:22 -0700508}
509
Omar Sandoval54d53292017-04-07 08:52:27 -0600510static void blk_mq_sched_tags_teardown(struct request_queue *q)
Jens Axboebd166ef2017-01-17 06:03:22 -0700511{
512 struct blk_mq_tag_set *set = q->tag_set;
513 struct blk_mq_hw_ctx *hctx;
514 int i;
515
516 queue_for_each_hw_ctx(q, hctx, i)
517 blk_mq_sched_free_tags(set, hctx, i);
518}
Jens Axboed3484992017-01-13 14:43:58 -0700519
Omar Sandoval93252632017-04-05 12:01:31 -0700520int blk_mq_sched_init_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
521 unsigned int hctx_idx)
522{
523 struct elevator_queue *e = q->elevator;
Omar Sandovalee056f92017-04-05 12:01:34 -0700524 int ret;
Omar Sandoval93252632017-04-05 12:01:31 -0700525
526 if (!e)
527 return 0;
528
Omar Sandovalee056f92017-04-05 12:01:34 -0700529 ret = blk_mq_sched_alloc_tags(q, hctx, hctx_idx);
530 if (ret)
531 return ret;
532
533 if (e->type->ops.mq.init_hctx) {
534 ret = e->type->ops.mq.init_hctx(hctx, hctx_idx);
535 if (ret) {
536 blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx);
537 return ret;
538 }
539 }
540
Omar Sandovald332ce02017-05-04 08:24:40 -0600541 blk_mq_debugfs_register_sched_hctx(q, hctx);
542
Omar Sandovalee056f92017-04-05 12:01:34 -0700543 return 0;
Omar Sandoval93252632017-04-05 12:01:31 -0700544}
545
546void blk_mq_sched_exit_hctx(struct request_queue *q, struct blk_mq_hw_ctx *hctx,
547 unsigned int hctx_idx)
548{
549 struct elevator_queue *e = q->elevator;
550
551 if (!e)
552 return;
553
Omar Sandovald332ce02017-05-04 08:24:40 -0600554 blk_mq_debugfs_unregister_sched_hctx(hctx);
555
Omar Sandovalee056f92017-04-05 12:01:34 -0700556 if (e->type->ops.mq.exit_hctx && hctx->sched_data) {
557 e->type->ops.mq.exit_hctx(hctx, hctx_idx);
558 hctx->sched_data = NULL;
559 }
560
Omar Sandoval93252632017-04-05 12:01:31 -0700561 blk_mq_sched_free_tags(q->tag_set, hctx, hctx_idx);
562}
563
Omar Sandoval6917ff02017-04-05 12:01:30 -0700564int blk_mq_init_sched(struct request_queue *q, struct elevator_type *e)
565{
566 struct blk_mq_hw_ctx *hctx;
Omar Sandovalee056f92017-04-05 12:01:34 -0700567 struct elevator_queue *eq;
Omar Sandoval6917ff02017-04-05 12:01:30 -0700568 unsigned int i;
569 int ret;
570
571 if (!e) {
572 q->elevator = NULL;
573 return 0;
574 }
575
576 /*
Ming Lei32825c42017-07-03 20:37:14 +0800577 * Default to double of smaller one between hw queue_depth and 128,
578 * since we don't split into sync/async like the old code did.
579 * Additionally, this is a per-hw queue depth.
Omar Sandoval6917ff02017-04-05 12:01:30 -0700580 */
Ming Lei32825c42017-07-03 20:37:14 +0800581 q->nr_requests = 2 * min_t(unsigned int, q->tag_set->queue_depth,
582 BLKDEV_MAX_RQ);
Omar Sandoval6917ff02017-04-05 12:01:30 -0700583
584 queue_for_each_hw_ctx(q, hctx, i) {
585 ret = blk_mq_sched_alloc_tags(q, hctx, i);
586 if (ret)
587 goto err;
588 }
589
590 ret = e->ops.mq.init_sched(q, e);
591 if (ret)
592 goto err;
593
Omar Sandovald332ce02017-05-04 08:24:40 -0600594 blk_mq_debugfs_register_sched(q);
595
596 queue_for_each_hw_ctx(q, hctx, i) {
597 if (e->ops.mq.init_hctx) {
Omar Sandovalee056f92017-04-05 12:01:34 -0700598 ret = e->ops.mq.init_hctx(hctx, i);
599 if (ret) {
600 eq = q->elevator;
601 blk_mq_exit_sched(q, eq);
602 kobject_put(&eq->kobj);
603 return ret;
604 }
605 }
Omar Sandovald332ce02017-05-04 08:24:40 -0600606 blk_mq_debugfs_register_sched_hctx(q, hctx);
Omar Sandovalee056f92017-04-05 12:01:34 -0700607 }
608
Omar Sandoval6917ff02017-04-05 12:01:30 -0700609 return 0;
610
611err:
Omar Sandoval54d53292017-04-07 08:52:27 -0600612 blk_mq_sched_tags_teardown(q);
613 q->elevator = NULL;
Omar Sandoval6917ff02017-04-05 12:01:30 -0700614 return ret;
615}
616
Omar Sandoval54d53292017-04-07 08:52:27 -0600617void blk_mq_exit_sched(struct request_queue *q, struct elevator_queue *e)
618{
Omar Sandovalee056f92017-04-05 12:01:34 -0700619 struct blk_mq_hw_ctx *hctx;
620 unsigned int i;
621
Omar Sandovald332ce02017-05-04 08:24:40 -0600622 queue_for_each_hw_ctx(q, hctx, i) {
623 blk_mq_debugfs_unregister_sched_hctx(hctx);
624 if (e->type->ops.mq.exit_hctx && hctx->sched_data) {
625 e->type->ops.mq.exit_hctx(hctx, i);
626 hctx->sched_data = NULL;
Omar Sandovalee056f92017-04-05 12:01:34 -0700627 }
628 }
Omar Sandovald332ce02017-05-04 08:24:40 -0600629 blk_mq_debugfs_unregister_sched(q);
Omar Sandoval54d53292017-04-07 08:52:27 -0600630 if (e->type->ops.mq.exit_sched)
631 e->type->ops.mq.exit_sched(e);
632 blk_mq_sched_tags_teardown(q);
633 q->elevator = NULL;
634}
635
Jens Axboed3484992017-01-13 14:43:58 -0700636int blk_mq_sched_init(struct request_queue *q)
637{
638 int ret;
639
Jens Axboed3484992017-01-13 14:43:58 -0700640 mutex_lock(&q->sysfs_lock);
641 ret = elevator_init(q, NULL);
642 mutex_unlock(&q->sysfs_lock);
643
644 return ret;
645}