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1 | /* | |
2 | * Block multiqueue core code | |
3 | * | |
4 | * Copyright (C) 2013-2014 Jens Axboe | |
5 | * Copyright (C) 2013-2014 Christoph Hellwig | |
6 | */ | |
7 | #include <linux/kernel.h> | |
8 | #include <linux/module.h> | |
9 | #include <linux/backing-dev.h> | |
10 | #include <linux/bio.h> | |
11 | #include <linux/blkdev.h> | |
12 | #include <linux/mm.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/slab.h> | |
15 | #include <linux/workqueue.h> | |
16 | #include <linux/smp.h> | |
17 | #include <linux/llist.h> | |
18 | #include <linux/list_sort.h> | |
19 | #include <linux/cpu.h> | |
20 | #include <linux/cache.h> | |
21 | #include <linux/sched/sysctl.h> | |
22 | #include <linux/delay.h> | |
23 | #include <linux/crash_dump.h> | |
24 | ||
25 | #include <trace/events/block.h> | |
26 | ||
27 | #include <linux/blk-mq.h> | |
28 | #include "blk.h" | |
29 | #include "blk-mq.h" | |
30 | #include "blk-mq-tag.h" | |
31 | ||
32 | static DEFINE_MUTEX(all_q_mutex); | |
33 | static LIST_HEAD(all_q_list); | |
34 | ||
35 | static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx); | |
36 | static void blk_mq_run_queues(struct request_queue *q); | |
37 | ||
38 | /* | |
39 | * Check if any of the ctx's have pending work in this hardware queue | |
40 | */ | |
41 | static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) | |
42 | { | |
43 | unsigned int i; | |
44 | ||
45 | for (i = 0; i < hctx->ctx_map.map_size; i++) | |
46 | if (hctx->ctx_map.map[i].word) | |
47 | return true; | |
48 | ||
49 | return false; | |
50 | } | |
51 | ||
52 | static inline struct blk_align_bitmap *get_bm(struct blk_mq_hw_ctx *hctx, | |
53 | struct blk_mq_ctx *ctx) | |
54 | { | |
55 | return &hctx->ctx_map.map[ctx->index_hw / hctx->ctx_map.bits_per_word]; | |
56 | } | |
57 | ||
58 | #define CTX_TO_BIT(hctx, ctx) \ | |
59 | ((ctx)->index_hw & ((hctx)->ctx_map.bits_per_word - 1)) | |
60 | ||
61 | /* | |
62 | * Mark this ctx as having pending work in this hardware queue | |
63 | */ | |
64 | static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx, | |
65 | struct blk_mq_ctx *ctx) | |
66 | { | |
67 | struct blk_align_bitmap *bm = get_bm(hctx, ctx); | |
68 | ||
69 | if (!test_bit(CTX_TO_BIT(hctx, ctx), &bm->word)) | |
70 | set_bit(CTX_TO_BIT(hctx, ctx), &bm->word); | |
71 | } | |
72 | ||
73 | static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, | |
74 | struct blk_mq_ctx *ctx) | |
75 | { | |
76 | struct blk_align_bitmap *bm = get_bm(hctx, ctx); | |
77 | ||
78 | clear_bit(CTX_TO_BIT(hctx, ctx), &bm->word); | |
79 | } | |
80 | ||
81 | static int blk_mq_queue_enter(struct request_queue *q) | |
82 | { | |
83 | while (true) { | |
84 | int ret; | |
85 | ||
86 | if (percpu_ref_tryget_live(&q->mq_usage_counter)) | |
87 | return 0; | |
88 | ||
89 | ret = wait_event_interruptible(q->mq_freeze_wq, | |
90 | !q->mq_freeze_depth || blk_queue_dying(q)); | |
91 | if (blk_queue_dying(q)) | |
92 | return -ENODEV; | |
93 | if (ret) | |
94 | return ret; | |
95 | } | |
96 | } | |
97 | ||
98 | static void blk_mq_queue_exit(struct request_queue *q) | |
99 | { | |
100 | percpu_ref_put(&q->mq_usage_counter); | |
101 | } | |
102 | ||
103 | static void blk_mq_usage_counter_release(struct percpu_ref *ref) | |
104 | { | |
105 | struct request_queue *q = | |
106 | container_of(ref, struct request_queue, mq_usage_counter); | |
107 | ||
108 | wake_up_all(&q->mq_freeze_wq); | |
109 | } | |
110 | ||
111 | void blk_mq_freeze_queue_start(struct request_queue *q) | |
112 | { | |
113 | bool freeze; | |
114 | ||
115 | spin_lock_irq(q->queue_lock); | |
116 | freeze = !q->mq_freeze_depth++; | |
117 | spin_unlock_irq(q->queue_lock); | |
118 | ||
119 | if (freeze) { | |
120 | percpu_ref_kill(&q->mq_usage_counter); | |
121 | blk_mq_run_queues(q); | |
122 | } | |
123 | } | |
124 | EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start); | |
125 | ||
126 | static void blk_mq_freeze_queue_wait(struct request_queue *q) | |
127 | { | |
128 | wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->mq_usage_counter)); | |
129 | } | |
130 | ||
131 | /* | |
132 | * Guarantee no request is in use, so we can change any data structure of | |
133 | * the queue afterward. | |
134 | */ | |
135 | void blk_mq_freeze_queue(struct request_queue *q) | |
136 | { | |
137 | blk_mq_freeze_queue_start(q); | |
138 | blk_mq_freeze_queue_wait(q); | |
139 | } | |
140 | EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); | |
141 | ||
142 | void blk_mq_unfreeze_queue(struct request_queue *q) | |
143 | { | |
144 | bool wake; | |
145 | ||
146 | spin_lock_irq(q->queue_lock); | |
147 | wake = !--q->mq_freeze_depth; | |
148 | WARN_ON_ONCE(q->mq_freeze_depth < 0); | |
149 | spin_unlock_irq(q->queue_lock); | |
150 | if (wake) { | |
151 | percpu_ref_reinit(&q->mq_usage_counter); | |
152 | wake_up_all(&q->mq_freeze_wq); | |
153 | } | |
154 | } | |
155 | EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); | |
156 | ||
157 | void blk_mq_wake_waiters(struct request_queue *q) | |
158 | { | |
159 | struct blk_mq_hw_ctx *hctx; | |
160 | unsigned int i; | |
161 | ||
162 | queue_for_each_hw_ctx(q, hctx, i) | |
163 | if (blk_mq_hw_queue_mapped(hctx)) | |
164 | blk_mq_tag_wakeup_all(hctx->tags, true); | |
165 | ||
166 | /* | |
167 | * If we are called because the queue has now been marked as | |
168 | * dying, we need to ensure that processes currently waiting on | |
169 | * the queue are notified as well. | |
170 | */ | |
171 | wake_up_all(&q->mq_freeze_wq); | |
172 | } | |
173 | ||
174 | bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx) | |
175 | { | |
176 | return blk_mq_has_free_tags(hctx->tags); | |
177 | } | |
178 | EXPORT_SYMBOL(blk_mq_can_queue); | |
179 | ||
180 | static void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx, | |
181 | struct request *rq, unsigned int rw_flags) | |
182 | { | |
183 | if (blk_queue_io_stat(q)) | |
184 | rw_flags |= REQ_IO_STAT; | |
185 | ||
186 | INIT_LIST_HEAD(&rq->queuelist); | |
187 | /* csd/requeue_work/fifo_time is initialized before use */ | |
188 | rq->q = q; | |
189 | rq->mq_ctx = ctx; | |
190 | rq->cmd_flags |= rw_flags; | |
191 | /* do not touch atomic flags, it needs atomic ops against the timer */ | |
192 | rq->cpu = -1; | |
193 | INIT_HLIST_NODE(&rq->hash); | |
194 | RB_CLEAR_NODE(&rq->rb_node); | |
195 | rq->rq_disk = NULL; | |
196 | rq->part = NULL; | |
197 | rq->start_time = jiffies; | |
198 | #ifdef CONFIG_BLK_CGROUP | |
199 | rq->rl = NULL; | |
200 | set_start_time_ns(rq); | |
201 | rq->io_start_time_ns = 0; | |
202 | #endif | |
203 | rq->nr_phys_segments = 0; | |
204 | #if defined(CONFIG_BLK_DEV_INTEGRITY) | |
205 | rq->nr_integrity_segments = 0; | |
206 | #endif | |
207 | rq->special = NULL; | |
208 | /* tag was already set */ | |
209 | rq->errors = 0; | |
210 | ||
211 | rq->cmd = rq->__cmd; | |
212 | ||
213 | rq->extra_len = 0; | |
214 | rq->sense_len = 0; | |
215 | rq->resid_len = 0; | |
216 | rq->sense = NULL; | |
217 | ||
218 | INIT_LIST_HEAD(&rq->timeout_list); | |
219 | rq->timeout = 0; | |
220 | ||
221 | rq->end_io = NULL; | |
222 | rq->end_io_data = NULL; | |
223 | rq->next_rq = NULL; | |
224 | ||
225 | ctx->rq_dispatched[rw_is_sync(rw_flags)]++; | |
226 | } | |
227 | ||
228 | static struct request * | |
229 | __blk_mq_alloc_request(struct blk_mq_alloc_data *data, int rw) | |
230 | { | |
231 | struct request *rq; | |
232 | unsigned int tag; | |
233 | ||
234 | tag = blk_mq_get_tag(data); | |
235 | if (tag != BLK_MQ_TAG_FAIL) { | |
236 | rq = data->hctx->tags->rqs[tag]; | |
237 | ||
238 | if (blk_mq_tag_busy(data->hctx)) { | |
239 | rq->cmd_flags = REQ_MQ_INFLIGHT; | |
240 | atomic_inc(&data->hctx->nr_active); | |
241 | } | |
242 | ||
243 | rq->tag = tag; | |
244 | blk_mq_rq_ctx_init(data->q, data->ctx, rq, rw); | |
245 | return rq; | |
246 | } | |
247 | ||
248 | return NULL; | |
249 | } | |
250 | ||
251 | struct request *blk_mq_alloc_request(struct request_queue *q, int rw, gfp_t gfp, | |
252 | bool reserved) | |
253 | { | |
254 | struct blk_mq_ctx *ctx; | |
255 | struct blk_mq_hw_ctx *hctx; | |
256 | struct request *rq; | |
257 | struct blk_mq_alloc_data alloc_data; | |
258 | int ret; | |
259 | ||
260 | ret = blk_mq_queue_enter(q); | |
261 | if (ret) | |
262 | return ERR_PTR(ret); | |
263 | ||
264 | ctx = blk_mq_get_ctx(q); | |
265 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
266 | blk_mq_set_alloc_data(&alloc_data, q, gfp & ~__GFP_WAIT, | |
267 | reserved, ctx, hctx); | |
268 | ||
269 | rq = __blk_mq_alloc_request(&alloc_data, rw); | |
270 | if (!rq && (gfp & __GFP_WAIT)) { | |
271 | __blk_mq_run_hw_queue(hctx); | |
272 | blk_mq_put_ctx(ctx); | |
273 | ||
274 | ctx = blk_mq_get_ctx(q); | |
275 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
276 | blk_mq_set_alloc_data(&alloc_data, q, gfp, reserved, ctx, | |
277 | hctx); | |
278 | rq = __blk_mq_alloc_request(&alloc_data, rw); | |
279 | ctx = alloc_data.ctx; | |
280 | } | |
281 | blk_mq_put_ctx(ctx); | |
282 | if (!rq) { | |
283 | blk_mq_queue_exit(q); | |
284 | return ERR_PTR(-EWOULDBLOCK); | |
285 | } | |
286 | return rq; | |
287 | } | |
288 | EXPORT_SYMBOL(blk_mq_alloc_request); | |
289 | ||
290 | static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx, | |
291 | struct blk_mq_ctx *ctx, struct request *rq) | |
292 | { | |
293 | const int tag = rq->tag; | |
294 | struct request_queue *q = rq->q; | |
295 | ||
296 | if (rq->cmd_flags & REQ_MQ_INFLIGHT) | |
297 | atomic_dec(&hctx->nr_active); | |
298 | rq->cmd_flags = 0; | |
299 | ||
300 | clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); | |
301 | blk_mq_put_tag(hctx, tag, &ctx->last_tag); | |
302 | blk_mq_queue_exit(q); | |
303 | } | |
304 | ||
305 | void blk_mq_free_hctx_request(struct blk_mq_hw_ctx *hctx, struct request *rq) | |
306 | { | |
307 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
308 | ||
309 | ctx->rq_completed[rq_is_sync(rq)]++; | |
310 | __blk_mq_free_request(hctx, ctx, rq); | |
311 | ||
312 | } | |
313 | EXPORT_SYMBOL_GPL(blk_mq_free_hctx_request); | |
314 | ||
315 | void blk_mq_free_request(struct request *rq) | |
316 | { | |
317 | struct blk_mq_hw_ctx *hctx; | |
318 | struct request_queue *q = rq->q; | |
319 | ||
320 | hctx = q->mq_ops->map_queue(q, rq->mq_ctx->cpu); | |
321 | blk_mq_free_hctx_request(hctx, rq); | |
322 | } | |
323 | EXPORT_SYMBOL_GPL(blk_mq_free_request); | |
324 | ||
325 | inline void __blk_mq_end_request(struct request *rq, int error) | |
326 | { | |
327 | blk_account_io_done(rq); | |
328 | ||
329 | if (rq->end_io) { | |
330 | rq->end_io(rq, error); | |
331 | } else { | |
332 | if (unlikely(blk_bidi_rq(rq))) | |
333 | blk_mq_free_request(rq->next_rq); | |
334 | blk_mq_free_request(rq); | |
335 | } | |
336 | } | |
337 | EXPORT_SYMBOL(__blk_mq_end_request); | |
338 | ||
339 | void blk_mq_end_request(struct request *rq, int error) | |
340 | { | |
341 | if (blk_update_request(rq, error, blk_rq_bytes(rq))) | |
342 | BUG(); | |
343 | __blk_mq_end_request(rq, error); | |
344 | } | |
345 | EXPORT_SYMBOL(blk_mq_end_request); | |
346 | ||
347 | static void __blk_mq_complete_request_remote(void *data) | |
348 | { | |
349 | struct request *rq = data; | |
350 | ||
351 | rq->q->softirq_done_fn(rq); | |
352 | } | |
353 | ||
354 | static void blk_mq_ipi_complete_request(struct request *rq) | |
355 | { | |
356 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
357 | bool shared = false; | |
358 | int cpu; | |
359 | ||
360 | if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) { | |
361 | rq->q->softirq_done_fn(rq); | |
362 | return; | |
363 | } | |
364 | ||
365 | cpu = get_cpu(); | |
366 | if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags)) | |
367 | shared = cpus_share_cache(cpu, ctx->cpu); | |
368 | ||
369 | if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { | |
370 | rq->csd.func = __blk_mq_complete_request_remote; | |
371 | rq->csd.info = rq; | |
372 | rq->csd.flags = 0; | |
373 | smp_call_function_single_async(ctx->cpu, &rq->csd); | |
374 | } else { | |
375 | rq->q->softirq_done_fn(rq); | |
376 | } | |
377 | put_cpu(); | |
378 | } | |
379 | ||
380 | void __blk_mq_complete_request(struct request *rq) | |
381 | { | |
382 | struct request_queue *q = rq->q; | |
383 | ||
384 | if (!q->softirq_done_fn) | |
385 | blk_mq_end_request(rq, rq->errors); | |
386 | else | |
387 | blk_mq_ipi_complete_request(rq); | |
388 | } | |
389 | ||
390 | /** | |
391 | * blk_mq_complete_request - end I/O on a request | |
392 | * @rq: the request being processed | |
393 | * | |
394 | * Description: | |
395 | * Ends all I/O on a request. It does not handle partial completions. | |
396 | * The actual completion happens out-of-order, through a IPI handler. | |
397 | **/ | |
398 | void blk_mq_complete_request(struct request *rq) | |
399 | { | |
400 | struct request_queue *q = rq->q; | |
401 | ||
402 | if (unlikely(blk_should_fake_timeout(q))) | |
403 | return; | |
404 | if (!blk_mark_rq_complete(rq)) | |
405 | __blk_mq_complete_request(rq); | |
406 | } | |
407 | EXPORT_SYMBOL(blk_mq_complete_request); | |
408 | ||
409 | int blk_mq_request_started(struct request *rq) | |
410 | { | |
411 | return test_bit(REQ_ATOM_STARTED, &rq->atomic_flags); | |
412 | } | |
413 | EXPORT_SYMBOL_GPL(blk_mq_request_started); | |
414 | ||
415 | void blk_mq_start_request(struct request *rq) | |
416 | { | |
417 | struct request_queue *q = rq->q; | |
418 | ||
419 | trace_block_rq_issue(q, rq); | |
420 | ||
421 | rq->resid_len = blk_rq_bytes(rq); | |
422 | if (unlikely(blk_bidi_rq(rq))) | |
423 | rq->next_rq->resid_len = blk_rq_bytes(rq->next_rq); | |
424 | ||
425 | blk_add_timer(rq); | |
426 | ||
427 | /* | |
428 | * Ensure that ->deadline is visible before set the started | |
429 | * flag and clear the completed flag. | |
430 | */ | |
431 | smp_mb__before_atomic(); | |
432 | ||
433 | /* | |
434 | * Mark us as started and clear complete. Complete might have been | |
435 | * set if requeue raced with timeout, which then marked it as | |
436 | * complete. So be sure to clear complete again when we start | |
437 | * the request, otherwise we'll ignore the completion event. | |
438 | */ | |
439 | if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) | |
440 | set_bit(REQ_ATOM_STARTED, &rq->atomic_flags); | |
441 | if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) | |
442 | clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); | |
443 | ||
444 | if (q->dma_drain_size && blk_rq_bytes(rq)) { | |
445 | /* | |
446 | * Make sure space for the drain appears. We know we can do | |
447 | * this because max_hw_segments has been adjusted to be one | |
448 | * fewer than the device can handle. | |
449 | */ | |
450 | rq->nr_phys_segments++; | |
451 | } | |
452 | } | |
453 | EXPORT_SYMBOL(blk_mq_start_request); | |
454 | ||
455 | static void __blk_mq_requeue_request(struct request *rq) | |
456 | { | |
457 | struct request_queue *q = rq->q; | |
458 | ||
459 | trace_block_rq_requeue(q, rq); | |
460 | ||
461 | if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { | |
462 | if (q->dma_drain_size && blk_rq_bytes(rq)) | |
463 | rq->nr_phys_segments--; | |
464 | } | |
465 | } | |
466 | ||
467 | void blk_mq_requeue_request(struct request *rq) | |
468 | { | |
469 | __blk_mq_requeue_request(rq); | |
470 | ||
471 | BUG_ON(blk_queued_rq(rq)); | |
472 | blk_mq_add_to_requeue_list(rq, true); | |
473 | } | |
474 | EXPORT_SYMBOL(blk_mq_requeue_request); | |
475 | ||
476 | static void blk_mq_requeue_work(struct work_struct *work) | |
477 | { | |
478 | struct request_queue *q = | |
479 | container_of(work, struct request_queue, requeue_work); | |
480 | LIST_HEAD(rq_list); | |
481 | struct request *rq, *next; | |
482 | unsigned long flags; | |
483 | ||
484 | spin_lock_irqsave(&q->requeue_lock, flags); | |
485 | list_splice_init(&q->requeue_list, &rq_list); | |
486 | spin_unlock_irqrestore(&q->requeue_lock, flags); | |
487 | ||
488 | list_for_each_entry_safe(rq, next, &rq_list, queuelist) { | |
489 | if (!(rq->cmd_flags & REQ_SOFTBARRIER)) | |
490 | continue; | |
491 | ||
492 | rq->cmd_flags &= ~REQ_SOFTBARRIER; | |
493 | list_del_init(&rq->queuelist); | |
494 | blk_mq_insert_request(rq, true, false, false); | |
495 | } | |
496 | ||
497 | while (!list_empty(&rq_list)) { | |
498 | rq = list_entry(rq_list.next, struct request, queuelist); | |
499 | list_del_init(&rq->queuelist); | |
500 | blk_mq_insert_request(rq, false, false, false); | |
501 | } | |
502 | ||
503 | /* | |
504 | * Use the start variant of queue running here, so that running | |
505 | * the requeue work will kick stopped queues. | |
506 | */ | |
507 | blk_mq_start_hw_queues(q); | |
508 | } | |
509 | ||
510 | void blk_mq_add_to_requeue_list(struct request *rq, bool at_head) | |
511 | { | |
512 | struct request_queue *q = rq->q; | |
513 | unsigned long flags; | |
514 | ||
515 | /* | |
516 | * We abuse this flag that is otherwise used by the I/O scheduler to | |
517 | * request head insertation from the workqueue. | |
518 | */ | |
519 | BUG_ON(rq->cmd_flags & REQ_SOFTBARRIER); | |
520 | ||
521 | spin_lock_irqsave(&q->requeue_lock, flags); | |
522 | if (at_head) { | |
523 | rq->cmd_flags |= REQ_SOFTBARRIER; | |
524 | list_add(&rq->queuelist, &q->requeue_list); | |
525 | } else { | |
526 | list_add_tail(&rq->queuelist, &q->requeue_list); | |
527 | } | |
528 | spin_unlock_irqrestore(&q->requeue_lock, flags); | |
529 | } | |
530 | EXPORT_SYMBOL(blk_mq_add_to_requeue_list); | |
531 | ||
532 | void blk_mq_cancel_requeue_work(struct request_queue *q) | |
533 | { | |
534 | cancel_work_sync(&q->requeue_work); | |
535 | } | |
536 | EXPORT_SYMBOL_GPL(blk_mq_cancel_requeue_work); | |
537 | ||
538 | void blk_mq_kick_requeue_list(struct request_queue *q) | |
539 | { | |
540 | kblockd_schedule_work(&q->requeue_work); | |
541 | } | |
542 | EXPORT_SYMBOL(blk_mq_kick_requeue_list); | |
543 | ||
544 | void blk_mq_abort_requeue_list(struct request_queue *q) | |
545 | { | |
546 | unsigned long flags; | |
547 | LIST_HEAD(rq_list); | |
548 | ||
549 | spin_lock_irqsave(&q->requeue_lock, flags); | |
550 | list_splice_init(&q->requeue_list, &rq_list); | |
551 | spin_unlock_irqrestore(&q->requeue_lock, flags); | |
552 | ||
553 | while (!list_empty(&rq_list)) { | |
554 | struct request *rq; | |
555 | ||
556 | rq = list_first_entry(&rq_list, struct request, queuelist); | |
557 | list_del_init(&rq->queuelist); | |
558 | rq->errors = -EIO; | |
559 | blk_mq_end_request(rq, rq->errors); | |
560 | } | |
561 | } | |
562 | EXPORT_SYMBOL(blk_mq_abort_requeue_list); | |
563 | ||
564 | static inline bool is_flush_request(struct request *rq, | |
565 | struct blk_flush_queue *fq, unsigned int tag) | |
566 | { | |
567 | return ((rq->cmd_flags & REQ_FLUSH_SEQ) && | |
568 | fq->flush_rq->tag == tag); | |
569 | } | |
570 | ||
571 | struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) | |
572 | { | |
573 | struct request *rq = tags->rqs[tag]; | |
574 | /* mq_ctx of flush rq is always cloned from the corresponding req */ | |
575 | struct blk_flush_queue *fq = blk_get_flush_queue(rq->q, rq->mq_ctx); | |
576 | ||
577 | if (!is_flush_request(rq, fq, tag)) | |
578 | return rq; | |
579 | ||
580 | return fq->flush_rq; | |
581 | } | |
582 | EXPORT_SYMBOL(blk_mq_tag_to_rq); | |
583 | ||
584 | struct blk_mq_timeout_data { | |
585 | unsigned long next; | |
586 | unsigned int next_set; | |
587 | }; | |
588 | ||
589 | void blk_mq_rq_timed_out(struct request *req, bool reserved) | |
590 | { | |
591 | struct blk_mq_ops *ops = req->q->mq_ops; | |
592 | enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER; | |
593 | ||
594 | /* | |
595 | * We know that complete is set at this point. If STARTED isn't set | |
596 | * anymore, then the request isn't active and the "timeout" should | |
597 | * just be ignored. This can happen due to the bitflag ordering. | |
598 | * Timeout first checks if STARTED is set, and if it is, assumes | |
599 | * the request is active. But if we race with completion, then | |
600 | * we both flags will get cleared. So check here again, and ignore | |
601 | * a timeout event with a request that isn't active. | |
602 | */ | |
603 | if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags)) | |
604 | return; | |
605 | ||
606 | if (ops->timeout) | |
607 | ret = ops->timeout(req, reserved); | |
608 | ||
609 | switch (ret) { | |
610 | case BLK_EH_HANDLED: | |
611 | __blk_mq_complete_request(req); | |
612 | break; | |
613 | case BLK_EH_RESET_TIMER: | |
614 | blk_add_timer(req); | |
615 | blk_clear_rq_complete(req); | |
616 | break; | |
617 | case BLK_EH_NOT_HANDLED: | |
618 | break; | |
619 | default: | |
620 | printk(KERN_ERR "block: bad eh return: %d\n", ret); | |
621 | break; | |
622 | } | |
623 | } | |
624 | ||
625 | static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, | |
626 | struct request *rq, void *priv, bool reserved) | |
627 | { | |
628 | struct blk_mq_timeout_data *data = priv; | |
629 | ||
630 | if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { | |
631 | /* | |
632 | * If a request wasn't started before the queue was | |
633 | * marked dying, kill it here or it'll go unnoticed. | |
634 | */ | |
635 | if (unlikely(blk_queue_dying(rq->q))) { | |
636 | rq->errors = -EIO; | |
637 | blk_mq_complete_request(rq); | |
638 | } | |
639 | return; | |
640 | } | |
641 | if (rq->cmd_flags & REQ_NO_TIMEOUT) | |
642 | return; | |
643 | ||
644 | if (time_after_eq(jiffies, rq->deadline)) { | |
645 | if (!blk_mark_rq_complete(rq)) | |
646 | blk_mq_rq_timed_out(rq, reserved); | |
647 | } else if (!data->next_set || time_after(data->next, rq->deadline)) { | |
648 | data->next = rq->deadline; | |
649 | data->next_set = 1; | |
650 | } | |
651 | } | |
652 | ||
653 | static void blk_mq_rq_timer(unsigned long priv) | |
654 | { | |
655 | struct request_queue *q = (struct request_queue *)priv; | |
656 | struct blk_mq_timeout_data data = { | |
657 | .next = 0, | |
658 | .next_set = 0, | |
659 | }; | |
660 | struct blk_mq_hw_ctx *hctx; | |
661 | int i; | |
662 | ||
663 | queue_for_each_hw_ctx(q, hctx, i) { | |
664 | /* | |
665 | * If not software queues are currently mapped to this | |
666 | * hardware queue, there's nothing to check | |
667 | */ | |
668 | if (!blk_mq_hw_queue_mapped(hctx)) | |
669 | continue; | |
670 | ||
671 | blk_mq_tag_busy_iter(hctx, blk_mq_check_expired, &data); | |
672 | } | |
673 | ||
674 | if (data.next_set) { | |
675 | data.next = blk_rq_timeout(round_jiffies_up(data.next)); | |
676 | mod_timer(&q->timeout, data.next); | |
677 | } else { | |
678 | queue_for_each_hw_ctx(q, hctx, i) | |
679 | blk_mq_tag_idle(hctx); | |
680 | } | |
681 | } | |
682 | ||
683 | /* | |
684 | * Reverse check our software queue for entries that we could potentially | |
685 | * merge with. Currently includes a hand-wavy stop count of 8, to not spend | |
686 | * too much time checking for merges. | |
687 | */ | |
688 | static bool blk_mq_attempt_merge(struct request_queue *q, | |
689 | struct blk_mq_ctx *ctx, struct bio *bio) | |
690 | { | |
691 | struct request *rq; | |
692 | int checked = 8; | |
693 | ||
694 | list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { | |
695 | int el_ret; | |
696 | ||
697 | if (!checked--) | |
698 | break; | |
699 | ||
700 | if (!blk_rq_merge_ok(rq, bio)) | |
701 | continue; | |
702 | ||
703 | el_ret = blk_try_merge(rq, bio); | |
704 | if (el_ret == ELEVATOR_BACK_MERGE) { | |
705 | if (bio_attempt_back_merge(q, rq, bio)) { | |
706 | ctx->rq_merged++; | |
707 | return true; | |
708 | } | |
709 | break; | |
710 | } else if (el_ret == ELEVATOR_FRONT_MERGE) { | |
711 | if (bio_attempt_front_merge(q, rq, bio)) { | |
712 | ctx->rq_merged++; | |
713 | return true; | |
714 | } | |
715 | break; | |
716 | } | |
717 | } | |
718 | ||
719 | return false; | |
720 | } | |
721 | ||
722 | /* | |
723 | * Process software queues that have been marked busy, splicing them | |
724 | * to the for-dispatch | |
725 | */ | |
726 | static void flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) | |
727 | { | |
728 | struct blk_mq_ctx *ctx; | |
729 | int i; | |
730 | ||
731 | for (i = 0; i < hctx->ctx_map.map_size; i++) { | |
732 | struct blk_align_bitmap *bm = &hctx->ctx_map.map[i]; | |
733 | unsigned int off, bit; | |
734 | ||
735 | if (!bm->word) | |
736 | continue; | |
737 | ||
738 | bit = 0; | |
739 | off = i * hctx->ctx_map.bits_per_word; | |
740 | do { | |
741 | bit = find_next_bit(&bm->word, bm->depth, bit); | |
742 | if (bit >= bm->depth) | |
743 | break; | |
744 | ||
745 | ctx = hctx->ctxs[bit + off]; | |
746 | clear_bit(bit, &bm->word); | |
747 | spin_lock(&ctx->lock); | |
748 | list_splice_tail_init(&ctx->rq_list, list); | |
749 | spin_unlock(&ctx->lock); | |
750 | ||
751 | bit++; | |
752 | } while (1); | |
753 | } | |
754 | } | |
755 | ||
756 | /* | |
757 | * Run this hardware queue, pulling any software queues mapped to it in. | |
758 | * Note that this function currently has various problems around ordering | |
759 | * of IO. In particular, we'd like FIFO behaviour on handling existing | |
760 | * items on the hctx->dispatch list. Ignore that for now. | |
761 | */ | |
762 | static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) | |
763 | { | |
764 | struct request_queue *q = hctx->queue; | |
765 | struct request *rq; | |
766 | LIST_HEAD(rq_list); | |
767 | LIST_HEAD(driver_list); | |
768 | struct list_head *dptr; | |
769 | int queued; | |
770 | ||
771 | WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)); | |
772 | ||
773 | if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state))) | |
774 | return; | |
775 | ||
776 | hctx->run++; | |
777 | ||
778 | /* | |
779 | * Touch any software queue that has pending entries. | |
780 | */ | |
781 | flush_busy_ctxs(hctx, &rq_list); | |
782 | ||
783 | /* | |
784 | * If we have previous entries on our dispatch list, grab them | |
785 | * and stuff them at the front for more fair dispatch. | |
786 | */ | |
787 | if (!list_empty_careful(&hctx->dispatch)) { | |
788 | spin_lock(&hctx->lock); | |
789 | if (!list_empty(&hctx->dispatch)) | |
790 | list_splice_init(&hctx->dispatch, &rq_list); | |
791 | spin_unlock(&hctx->lock); | |
792 | } | |
793 | ||
794 | /* | |
795 | * Start off with dptr being NULL, so we start the first request | |
796 | * immediately, even if we have more pending. | |
797 | */ | |
798 | dptr = NULL; | |
799 | ||
800 | /* | |
801 | * Now process all the entries, sending them to the driver. | |
802 | */ | |
803 | queued = 0; | |
804 | while (!list_empty(&rq_list)) { | |
805 | struct blk_mq_queue_data bd; | |
806 | int ret; | |
807 | ||
808 | rq = list_first_entry(&rq_list, struct request, queuelist); | |
809 | list_del_init(&rq->queuelist); | |
810 | ||
811 | bd.rq = rq; | |
812 | bd.list = dptr; | |
813 | bd.last = list_empty(&rq_list); | |
814 | ||
815 | ret = q->mq_ops->queue_rq(hctx, &bd); | |
816 | switch (ret) { | |
817 | case BLK_MQ_RQ_QUEUE_OK: | |
818 | queued++; | |
819 | continue; | |
820 | case BLK_MQ_RQ_QUEUE_BUSY: | |
821 | list_add(&rq->queuelist, &rq_list); | |
822 | __blk_mq_requeue_request(rq); | |
823 | break; | |
824 | default: | |
825 | pr_err("blk-mq: bad return on queue: %d\n", ret); | |
826 | case BLK_MQ_RQ_QUEUE_ERROR: | |
827 | rq->errors = -EIO; | |
828 | blk_mq_end_request(rq, rq->errors); | |
829 | break; | |
830 | } | |
831 | ||
832 | if (ret == BLK_MQ_RQ_QUEUE_BUSY) | |
833 | break; | |
834 | ||
835 | /* | |
836 | * We've done the first request. If we have more than 1 | |
837 | * left in the list, set dptr to defer issue. | |
838 | */ | |
839 | if (!dptr && rq_list.next != rq_list.prev) | |
840 | dptr = &driver_list; | |
841 | } | |
842 | ||
843 | if (!queued) | |
844 | hctx->dispatched[0]++; | |
845 | else if (queued < (1 << (BLK_MQ_MAX_DISPATCH_ORDER - 1))) | |
846 | hctx->dispatched[ilog2(queued) + 1]++; | |
847 | ||
848 | /* | |
849 | * Any items that need requeuing? Stuff them into hctx->dispatch, | |
850 | * that is where we will continue on next queue run. | |
851 | */ | |
852 | if (!list_empty(&rq_list)) { | |
853 | spin_lock(&hctx->lock); | |
854 | list_splice(&rq_list, &hctx->dispatch); | |
855 | spin_unlock(&hctx->lock); | |
856 | } | |
857 | } | |
858 | ||
859 | /* | |
860 | * It'd be great if the workqueue API had a way to pass | |
861 | * in a mask and had some smarts for more clever placement. | |
862 | * For now we just round-robin here, switching for every | |
863 | * BLK_MQ_CPU_WORK_BATCH queued items. | |
864 | */ | |
865 | static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) | |
866 | { | |
867 | if (hctx->queue->nr_hw_queues == 1) | |
868 | return WORK_CPU_UNBOUND; | |
869 | ||
870 | if (--hctx->next_cpu_batch <= 0) { | |
871 | int cpu = hctx->next_cpu, next_cpu; | |
872 | ||
873 | next_cpu = cpumask_next(hctx->next_cpu, hctx->cpumask); | |
874 | if (next_cpu >= nr_cpu_ids) | |
875 | next_cpu = cpumask_first(hctx->cpumask); | |
876 | ||
877 | hctx->next_cpu = next_cpu; | |
878 | hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; | |
879 | ||
880 | return cpu; | |
881 | } | |
882 | ||
883 | return hctx->next_cpu; | |
884 | } | |
885 | ||
886 | void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) | |
887 | { | |
888 | if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state) || | |
889 | !blk_mq_hw_queue_mapped(hctx))) | |
890 | return; | |
891 | ||
892 | if (!async) { | |
893 | int cpu = get_cpu(); | |
894 | if (cpumask_test_cpu(cpu, hctx->cpumask)) { | |
895 | __blk_mq_run_hw_queue(hctx); | |
896 | put_cpu(); | |
897 | return; | |
898 | } | |
899 | ||
900 | put_cpu(); | |
901 | } | |
902 | ||
903 | kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), | |
904 | &hctx->run_work, 0); | |
905 | } | |
906 | ||
907 | static void blk_mq_run_queues(struct request_queue *q) | |
908 | { | |
909 | struct blk_mq_hw_ctx *hctx; | |
910 | int i; | |
911 | ||
912 | queue_for_each_hw_ctx(q, hctx, i) { | |
913 | if ((!blk_mq_hctx_has_pending(hctx) && | |
914 | list_empty_careful(&hctx->dispatch)) || | |
915 | test_bit(BLK_MQ_S_STOPPED, &hctx->state)) | |
916 | continue; | |
917 | ||
918 | blk_mq_run_hw_queue(hctx, false); | |
919 | } | |
920 | } | |
921 | ||
922 | void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) | |
923 | { | |
924 | cancel_delayed_work(&hctx->run_work); | |
925 | cancel_delayed_work(&hctx->delay_work); | |
926 | set_bit(BLK_MQ_S_STOPPED, &hctx->state); | |
927 | } | |
928 | EXPORT_SYMBOL(blk_mq_stop_hw_queue); | |
929 | ||
930 | void blk_mq_stop_hw_queues(struct request_queue *q) | |
931 | { | |
932 | struct blk_mq_hw_ctx *hctx; | |
933 | int i; | |
934 | ||
935 | queue_for_each_hw_ctx(q, hctx, i) | |
936 | blk_mq_stop_hw_queue(hctx); | |
937 | } | |
938 | EXPORT_SYMBOL(blk_mq_stop_hw_queues); | |
939 | ||
940 | void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) | |
941 | { | |
942 | clear_bit(BLK_MQ_S_STOPPED, &hctx->state); | |
943 | ||
944 | blk_mq_run_hw_queue(hctx, false); | |
945 | } | |
946 | EXPORT_SYMBOL(blk_mq_start_hw_queue); | |
947 | ||
948 | void blk_mq_start_hw_queues(struct request_queue *q) | |
949 | { | |
950 | struct blk_mq_hw_ctx *hctx; | |
951 | int i; | |
952 | ||
953 | queue_for_each_hw_ctx(q, hctx, i) | |
954 | blk_mq_start_hw_queue(hctx); | |
955 | } | |
956 | EXPORT_SYMBOL(blk_mq_start_hw_queues); | |
957 | ||
958 | void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) | |
959 | { | |
960 | struct blk_mq_hw_ctx *hctx; | |
961 | int i; | |
962 | ||
963 | queue_for_each_hw_ctx(q, hctx, i) { | |
964 | if (!test_bit(BLK_MQ_S_STOPPED, &hctx->state)) | |
965 | continue; | |
966 | ||
967 | clear_bit(BLK_MQ_S_STOPPED, &hctx->state); | |
968 | blk_mq_run_hw_queue(hctx, async); | |
969 | } | |
970 | } | |
971 | EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); | |
972 | ||
973 | static void blk_mq_run_work_fn(struct work_struct *work) | |
974 | { | |
975 | struct blk_mq_hw_ctx *hctx; | |
976 | ||
977 | hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); | |
978 | ||
979 | __blk_mq_run_hw_queue(hctx); | |
980 | } | |
981 | ||
982 | static void blk_mq_delay_work_fn(struct work_struct *work) | |
983 | { | |
984 | struct blk_mq_hw_ctx *hctx; | |
985 | ||
986 | hctx = container_of(work, struct blk_mq_hw_ctx, delay_work.work); | |
987 | ||
988 | if (test_and_clear_bit(BLK_MQ_S_STOPPED, &hctx->state)) | |
989 | __blk_mq_run_hw_queue(hctx); | |
990 | } | |
991 | ||
992 | void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) | |
993 | { | |
994 | if (unlikely(!blk_mq_hw_queue_mapped(hctx))) | |
995 | return; | |
996 | ||
997 | kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), | |
998 | &hctx->delay_work, msecs_to_jiffies(msecs)); | |
999 | } | |
1000 | EXPORT_SYMBOL(blk_mq_delay_queue); | |
1001 | ||
1002 | static void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, | |
1003 | struct request *rq, bool at_head) | |
1004 | { | |
1005 | struct blk_mq_ctx *ctx = rq->mq_ctx; | |
1006 | ||
1007 | trace_block_rq_insert(hctx->queue, rq); | |
1008 | ||
1009 | if (at_head) | |
1010 | list_add(&rq->queuelist, &ctx->rq_list); | |
1011 | else | |
1012 | list_add_tail(&rq->queuelist, &ctx->rq_list); | |
1013 | ||
1014 | blk_mq_hctx_mark_pending(hctx, ctx); | |
1015 | } | |
1016 | ||
1017 | void blk_mq_insert_request(struct request *rq, bool at_head, bool run_queue, | |
1018 | bool async) | |
1019 | { | |
1020 | struct request_queue *q = rq->q; | |
1021 | struct blk_mq_hw_ctx *hctx; | |
1022 | struct blk_mq_ctx *ctx = rq->mq_ctx, *current_ctx; | |
1023 | ||
1024 | current_ctx = blk_mq_get_ctx(q); | |
1025 | if (!cpu_online(ctx->cpu)) | |
1026 | rq->mq_ctx = ctx = current_ctx; | |
1027 | ||
1028 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
1029 | ||
1030 | spin_lock(&ctx->lock); | |
1031 | __blk_mq_insert_request(hctx, rq, at_head); | |
1032 | spin_unlock(&ctx->lock); | |
1033 | ||
1034 | if (run_queue) | |
1035 | blk_mq_run_hw_queue(hctx, async); | |
1036 | ||
1037 | blk_mq_put_ctx(current_ctx); | |
1038 | } | |
1039 | ||
1040 | static void blk_mq_insert_requests(struct request_queue *q, | |
1041 | struct blk_mq_ctx *ctx, | |
1042 | struct list_head *list, | |
1043 | int depth, | |
1044 | bool from_schedule) | |
1045 | ||
1046 | { | |
1047 | struct blk_mq_hw_ctx *hctx; | |
1048 | struct blk_mq_ctx *current_ctx; | |
1049 | ||
1050 | trace_block_unplug(q, depth, !from_schedule); | |
1051 | ||
1052 | current_ctx = blk_mq_get_ctx(q); | |
1053 | ||
1054 | if (!cpu_online(ctx->cpu)) | |
1055 | ctx = current_ctx; | |
1056 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
1057 | ||
1058 | /* | |
1059 | * preemption doesn't flush plug list, so it's possible ctx->cpu is | |
1060 | * offline now | |
1061 | */ | |
1062 | spin_lock(&ctx->lock); | |
1063 | while (!list_empty(list)) { | |
1064 | struct request *rq; | |
1065 | ||
1066 | rq = list_first_entry(list, struct request, queuelist); | |
1067 | list_del_init(&rq->queuelist); | |
1068 | rq->mq_ctx = ctx; | |
1069 | __blk_mq_insert_request(hctx, rq, false); | |
1070 | } | |
1071 | spin_unlock(&ctx->lock); | |
1072 | ||
1073 | blk_mq_run_hw_queue(hctx, from_schedule); | |
1074 | blk_mq_put_ctx(current_ctx); | |
1075 | } | |
1076 | ||
1077 | static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b) | |
1078 | { | |
1079 | struct request *rqa = container_of(a, struct request, queuelist); | |
1080 | struct request *rqb = container_of(b, struct request, queuelist); | |
1081 | ||
1082 | return !(rqa->mq_ctx < rqb->mq_ctx || | |
1083 | (rqa->mq_ctx == rqb->mq_ctx && | |
1084 | blk_rq_pos(rqa) < blk_rq_pos(rqb))); | |
1085 | } | |
1086 | ||
1087 | void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) | |
1088 | { | |
1089 | struct blk_mq_ctx *this_ctx; | |
1090 | struct request_queue *this_q; | |
1091 | struct request *rq; | |
1092 | LIST_HEAD(list); | |
1093 | LIST_HEAD(ctx_list); | |
1094 | unsigned int depth; | |
1095 | ||
1096 | list_splice_init(&plug->mq_list, &list); | |
1097 | ||
1098 | list_sort(NULL, &list, plug_ctx_cmp); | |
1099 | ||
1100 | this_q = NULL; | |
1101 | this_ctx = NULL; | |
1102 | depth = 0; | |
1103 | ||
1104 | while (!list_empty(&list)) { | |
1105 | rq = list_entry_rq(list.next); | |
1106 | list_del_init(&rq->queuelist); | |
1107 | BUG_ON(!rq->q); | |
1108 | if (rq->mq_ctx != this_ctx) { | |
1109 | if (this_ctx) { | |
1110 | blk_mq_insert_requests(this_q, this_ctx, | |
1111 | &ctx_list, depth, | |
1112 | from_schedule); | |
1113 | } | |
1114 | ||
1115 | this_ctx = rq->mq_ctx; | |
1116 | this_q = rq->q; | |
1117 | depth = 0; | |
1118 | } | |
1119 | ||
1120 | depth++; | |
1121 | list_add_tail(&rq->queuelist, &ctx_list); | |
1122 | } | |
1123 | ||
1124 | /* | |
1125 | * If 'this_ctx' is set, we know we have entries to complete | |
1126 | * on 'ctx_list'. Do those. | |
1127 | */ | |
1128 | if (this_ctx) { | |
1129 | blk_mq_insert_requests(this_q, this_ctx, &ctx_list, depth, | |
1130 | from_schedule); | |
1131 | } | |
1132 | } | |
1133 | ||
1134 | static void blk_mq_bio_to_request(struct request *rq, struct bio *bio) | |
1135 | { | |
1136 | init_request_from_bio(rq, bio); | |
1137 | ||
1138 | if (blk_do_io_stat(rq)) | |
1139 | blk_account_io_start(rq, 1); | |
1140 | } | |
1141 | ||
1142 | static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx) | |
1143 | { | |
1144 | return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) && | |
1145 | !blk_queue_nomerges(hctx->queue); | |
1146 | } | |
1147 | ||
1148 | static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx, | |
1149 | struct blk_mq_ctx *ctx, | |
1150 | struct request *rq, struct bio *bio) | |
1151 | { | |
1152 | if (!hctx_allow_merges(hctx)) { | |
1153 | blk_mq_bio_to_request(rq, bio); | |
1154 | spin_lock(&ctx->lock); | |
1155 | insert_rq: | |
1156 | __blk_mq_insert_request(hctx, rq, false); | |
1157 | spin_unlock(&ctx->lock); | |
1158 | return false; | |
1159 | } else { | |
1160 | struct request_queue *q = hctx->queue; | |
1161 | ||
1162 | spin_lock(&ctx->lock); | |
1163 | if (!blk_mq_attempt_merge(q, ctx, bio)) { | |
1164 | blk_mq_bio_to_request(rq, bio); | |
1165 | goto insert_rq; | |
1166 | } | |
1167 | ||
1168 | spin_unlock(&ctx->lock); | |
1169 | __blk_mq_free_request(hctx, ctx, rq); | |
1170 | return true; | |
1171 | } | |
1172 | } | |
1173 | ||
1174 | struct blk_map_ctx { | |
1175 | struct blk_mq_hw_ctx *hctx; | |
1176 | struct blk_mq_ctx *ctx; | |
1177 | }; | |
1178 | ||
1179 | static struct request *blk_mq_map_request(struct request_queue *q, | |
1180 | struct bio *bio, | |
1181 | struct blk_map_ctx *data) | |
1182 | { | |
1183 | struct blk_mq_hw_ctx *hctx; | |
1184 | struct blk_mq_ctx *ctx; | |
1185 | struct request *rq; | |
1186 | int rw = bio_data_dir(bio); | |
1187 | struct blk_mq_alloc_data alloc_data; | |
1188 | ||
1189 | if (unlikely(blk_mq_queue_enter(q))) { | |
1190 | bio_endio(bio, -EIO); | |
1191 | return NULL; | |
1192 | } | |
1193 | ||
1194 | ctx = blk_mq_get_ctx(q); | |
1195 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
1196 | ||
1197 | if (rw_is_sync(bio->bi_rw)) | |
1198 | rw |= REQ_SYNC; | |
1199 | ||
1200 | trace_block_getrq(q, bio, rw); | |
1201 | blk_mq_set_alloc_data(&alloc_data, q, GFP_ATOMIC, false, ctx, | |
1202 | hctx); | |
1203 | rq = __blk_mq_alloc_request(&alloc_data, rw); | |
1204 | if (unlikely(!rq)) { | |
1205 | __blk_mq_run_hw_queue(hctx); | |
1206 | blk_mq_put_ctx(ctx); | |
1207 | trace_block_sleeprq(q, bio, rw); | |
1208 | ||
1209 | ctx = blk_mq_get_ctx(q); | |
1210 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
1211 | blk_mq_set_alloc_data(&alloc_data, q, | |
1212 | __GFP_WAIT|GFP_ATOMIC, false, ctx, hctx); | |
1213 | rq = __blk_mq_alloc_request(&alloc_data, rw); | |
1214 | ctx = alloc_data.ctx; | |
1215 | hctx = alloc_data.hctx; | |
1216 | } | |
1217 | ||
1218 | hctx->queued++; | |
1219 | data->hctx = hctx; | |
1220 | data->ctx = ctx; | |
1221 | return rq; | |
1222 | } | |
1223 | ||
1224 | /* | |
1225 | * Multiple hardware queue variant. This will not use per-process plugs, | |
1226 | * but will attempt to bypass the hctx queueing if we can go straight to | |
1227 | * hardware for SYNC IO. | |
1228 | */ | |
1229 | static void blk_mq_make_request(struct request_queue *q, struct bio *bio) | |
1230 | { | |
1231 | const int is_sync = rw_is_sync(bio->bi_rw); | |
1232 | const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA); | |
1233 | struct blk_map_ctx data; | |
1234 | struct request *rq; | |
1235 | ||
1236 | blk_queue_bounce(q, &bio); | |
1237 | ||
1238 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { | |
1239 | bio_endio(bio, -EIO); | |
1240 | return; | |
1241 | } | |
1242 | ||
1243 | rq = blk_mq_map_request(q, bio, &data); | |
1244 | if (unlikely(!rq)) | |
1245 | return; | |
1246 | ||
1247 | if (unlikely(is_flush_fua)) { | |
1248 | blk_mq_bio_to_request(rq, bio); | |
1249 | blk_insert_flush(rq); | |
1250 | goto run_queue; | |
1251 | } | |
1252 | ||
1253 | /* | |
1254 | * If the driver supports defer issued based on 'last', then | |
1255 | * queue it up like normal since we can potentially save some | |
1256 | * CPU this way. | |
1257 | */ | |
1258 | if (is_sync && !(data.hctx->flags & BLK_MQ_F_DEFER_ISSUE)) { | |
1259 | struct blk_mq_queue_data bd = { | |
1260 | .rq = rq, | |
1261 | .list = NULL, | |
1262 | .last = 1 | |
1263 | }; | |
1264 | int ret; | |
1265 | ||
1266 | blk_mq_bio_to_request(rq, bio); | |
1267 | ||
1268 | /* | |
1269 | * For OK queue, we are done. For error, kill it. Any other | |
1270 | * error (busy), just add it to our list as we previously | |
1271 | * would have done | |
1272 | */ | |
1273 | ret = q->mq_ops->queue_rq(data.hctx, &bd); | |
1274 | if (ret == BLK_MQ_RQ_QUEUE_OK) | |
1275 | goto done; | |
1276 | else { | |
1277 | __blk_mq_requeue_request(rq); | |
1278 | ||
1279 | if (ret == BLK_MQ_RQ_QUEUE_ERROR) { | |
1280 | rq->errors = -EIO; | |
1281 | blk_mq_end_request(rq, rq->errors); | |
1282 | goto done; | |
1283 | } | |
1284 | } | |
1285 | } | |
1286 | ||
1287 | if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { | |
1288 | /* | |
1289 | * For a SYNC request, send it to the hardware immediately. For | |
1290 | * an ASYNC request, just ensure that we run it later on. The | |
1291 | * latter allows for merging opportunities and more efficient | |
1292 | * dispatching. | |
1293 | */ | |
1294 | run_queue: | |
1295 | blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua); | |
1296 | } | |
1297 | done: | |
1298 | blk_mq_put_ctx(data.ctx); | |
1299 | } | |
1300 | ||
1301 | /* | |
1302 | * Single hardware queue variant. This will attempt to use any per-process | |
1303 | * plug for merging and IO deferral. | |
1304 | */ | |
1305 | static void blk_sq_make_request(struct request_queue *q, struct bio *bio) | |
1306 | { | |
1307 | const int is_sync = rw_is_sync(bio->bi_rw); | |
1308 | const int is_flush_fua = bio->bi_rw & (REQ_FLUSH | REQ_FUA); | |
1309 | unsigned int use_plug, request_count = 0; | |
1310 | struct blk_map_ctx data; | |
1311 | struct request *rq; | |
1312 | ||
1313 | /* | |
1314 | * If we have multiple hardware queues, just go directly to | |
1315 | * one of those for sync IO. | |
1316 | */ | |
1317 | use_plug = !is_flush_fua && !is_sync; | |
1318 | ||
1319 | blk_queue_bounce(q, &bio); | |
1320 | ||
1321 | if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) { | |
1322 | bio_endio(bio, -EIO); | |
1323 | return; | |
1324 | } | |
1325 | ||
1326 | if (use_plug && !blk_queue_nomerges(q) && | |
1327 | blk_attempt_plug_merge(q, bio, &request_count)) | |
1328 | return; | |
1329 | ||
1330 | rq = blk_mq_map_request(q, bio, &data); | |
1331 | if (unlikely(!rq)) | |
1332 | return; | |
1333 | ||
1334 | if (unlikely(is_flush_fua)) { | |
1335 | blk_mq_bio_to_request(rq, bio); | |
1336 | blk_insert_flush(rq); | |
1337 | goto run_queue; | |
1338 | } | |
1339 | ||
1340 | /* | |
1341 | * A task plug currently exists. Since this is completely lockless, | |
1342 | * utilize that to temporarily store requests until the task is | |
1343 | * either done or scheduled away. | |
1344 | */ | |
1345 | if (use_plug) { | |
1346 | struct blk_plug *plug = current->plug; | |
1347 | ||
1348 | if (plug) { | |
1349 | blk_mq_bio_to_request(rq, bio); | |
1350 | if (list_empty(&plug->mq_list)) | |
1351 | trace_block_plug(q); | |
1352 | else if (request_count >= BLK_MAX_REQUEST_COUNT) { | |
1353 | blk_flush_plug_list(plug, false); | |
1354 | trace_block_plug(q); | |
1355 | } | |
1356 | list_add_tail(&rq->queuelist, &plug->mq_list); | |
1357 | blk_mq_put_ctx(data.ctx); | |
1358 | return; | |
1359 | } | |
1360 | } | |
1361 | ||
1362 | if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) { | |
1363 | /* | |
1364 | * For a SYNC request, send it to the hardware immediately. For | |
1365 | * an ASYNC request, just ensure that we run it later on. The | |
1366 | * latter allows for merging opportunities and more efficient | |
1367 | * dispatching. | |
1368 | */ | |
1369 | run_queue: | |
1370 | blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua); | |
1371 | } | |
1372 | ||
1373 | blk_mq_put_ctx(data.ctx); | |
1374 | } | |
1375 | ||
1376 | /* | |
1377 | * Default mapping to a software queue, since we use one per CPU. | |
1378 | */ | |
1379 | struct blk_mq_hw_ctx *blk_mq_map_queue(struct request_queue *q, const int cpu) | |
1380 | { | |
1381 | return q->queue_hw_ctx[q->mq_map[cpu]]; | |
1382 | } | |
1383 | EXPORT_SYMBOL(blk_mq_map_queue); | |
1384 | ||
1385 | static void blk_mq_free_rq_map(struct blk_mq_tag_set *set, | |
1386 | struct blk_mq_tags *tags, unsigned int hctx_idx) | |
1387 | { | |
1388 | struct page *page; | |
1389 | ||
1390 | if (tags->rqs && set->ops->exit_request) { | |
1391 | int i; | |
1392 | ||
1393 | for (i = 0; i < tags->nr_tags; i++) { | |
1394 | if (!tags->rqs[i]) | |
1395 | continue; | |
1396 | set->ops->exit_request(set->driver_data, tags->rqs[i], | |
1397 | hctx_idx, i); | |
1398 | tags->rqs[i] = NULL; | |
1399 | } | |
1400 | } | |
1401 | ||
1402 | while (!list_empty(&tags->page_list)) { | |
1403 | page = list_first_entry(&tags->page_list, struct page, lru); | |
1404 | list_del_init(&page->lru); | |
1405 | __free_pages(page, page->private); | |
1406 | } | |
1407 | ||
1408 | kfree(tags->rqs); | |
1409 | ||
1410 | blk_mq_free_tags(tags); | |
1411 | } | |
1412 | ||
1413 | static size_t order_to_size(unsigned int order) | |
1414 | { | |
1415 | return (size_t)PAGE_SIZE << order; | |
1416 | } | |
1417 | ||
1418 | static struct blk_mq_tags *blk_mq_init_rq_map(struct blk_mq_tag_set *set, | |
1419 | unsigned int hctx_idx) | |
1420 | { | |
1421 | struct blk_mq_tags *tags; | |
1422 | unsigned int i, j, entries_per_page, max_order = 4; | |
1423 | size_t rq_size, left; | |
1424 | ||
1425 | tags = blk_mq_init_tags(set->queue_depth, set->reserved_tags, | |
1426 | set->numa_node, | |
1427 | BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags)); | |
1428 | if (!tags) | |
1429 | return NULL; | |
1430 | ||
1431 | INIT_LIST_HEAD(&tags->page_list); | |
1432 | ||
1433 | tags->rqs = kzalloc_node(set->queue_depth * sizeof(struct request *), | |
1434 | GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY, | |
1435 | set->numa_node); | |
1436 | if (!tags->rqs) { | |
1437 | blk_mq_free_tags(tags); | |
1438 | return NULL; | |
1439 | } | |
1440 | ||
1441 | /* | |
1442 | * rq_size is the size of the request plus driver payload, rounded | |
1443 | * to the cacheline size | |
1444 | */ | |
1445 | rq_size = round_up(sizeof(struct request) + set->cmd_size, | |
1446 | cache_line_size()); | |
1447 | left = rq_size * set->queue_depth; | |
1448 | ||
1449 | for (i = 0; i < set->queue_depth; ) { | |
1450 | int this_order = max_order; | |
1451 | struct page *page; | |
1452 | int to_do; | |
1453 | void *p; | |
1454 | ||
1455 | while (left < order_to_size(this_order - 1) && this_order) | |
1456 | this_order--; | |
1457 | ||
1458 | do { | |
1459 | page = alloc_pages_node(set->numa_node, | |
1460 | GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY, | |
1461 | this_order); | |
1462 | if (page) | |
1463 | break; | |
1464 | if (!this_order--) | |
1465 | break; | |
1466 | if (order_to_size(this_order) < rq_size) | |
1467 | break; | |
1468 | } while (1); | |
1469 | ||
1470 | if (!page) | |
1471 | goto fail; | |
1472 | ||
1473 | page->private = this_order; | |
1474 | list_add_tail(&page->lru, &tags->page_list); | |
1475 | ||
1476 | p = page_address(page); | |
1477 | entries_per_page = order_to_size(this_order) / rq_size; | |
1478 | to_do = min(entries_per_page, set->queue_depth - i); | |
1479 | left -= to_do * rq_size; | |
1480 | for (j = 0; j < to_do; j++) { | |
1481 | tags->rqs[i] = p; | |
1482 | tags->rqs[i]->atomic_flags = 0; | |
1483 | tags->rqs[i]->cmd_flags = 0; | |
1484 | if (set->ops->init_request) { | |
1485 | if (set->ops->init_request(set->driver_data, | |
1486 | tags->rqs[i], hctx_idx, i, | |
1487 | set->numa_node)) { | |
1488 | tags->rqs[i] = NULL; | |
1489 | goto fail; | |
1490 | } | |
1491 | } | |
1492 | ||
1493 | p += rq_size; | |
1494 | i++; | |
1495 | } | |
1496 | } | |
1497 | ||
1498 | return tags; | |
1499 | ||
1500 | fail: | |
1501 | blk_mq_free_rq_map(set, tags, hctx_idx); | |
1502 | return NULL; | |
1503 | } | |
1504 | ||
1505 | static void blk_mq_free_bitmap(struct blk_mq_ctxmap *bitmap) | |
1506 | { | |
1507 | kfree(bitmap->map); | |
1508 | } | |
1509 | ||
1510 | static int blk_mq_alloc_bitmap(struct blk_mq_ctxmap *bitmap, int node) | |
1511 | { | |
1512 | unsigned int bpw = 8, total, num_maps, i; | |
1513 | ||
1514 | bitmap->bits_per_word = bpw; | |
1515 | ||
1516 | num_maps = ALIGN(nr_cpu_ids, bpw) / bpw; | |
1517 | bitmap->map = kzalloc_node(num_maps * sizeof(struct blk_align_bitmap), | |
1518 | GFP_KERNEL, node); | |
1519 | if (!bitmap->map) | |
1520 | return -ENOMEM; | |
1521 | ||
1522 | bitmap->map_size = num_maps; | |
1523 | ||
1524 | total = nr_cpu_ids; | |
1525 | for (i = 0; i < num_maps; i++) { | |
1526 | bitmap->map[i].depth = min(total, bitmap->bits_per_word); | |
1527 | total -= bitmap->map[i].depth; | |
1528 | } | |
1529 | ||
1530 | return 0; | |
1531 | } | |
1532 | ||
1533 | static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu) | |
1534 | { | |
1535 | struct request_queue *q = hctx->queue; | |
1536 | struct blk_mq_ctx *ctx; | |
1537 | LIST_HEAD(tmp); | |
1538 | ||
1539 | /* | |
1540 | * Move ctx entries to new CPU, if this one is going away. | |
1541 | */ | |
1542 | ctx = __blk_mq_get_ctx(q, cpu); | |
1543 | ||
1544 | spin_lock(&ctx->lock); | |
1545 | if (!list_empty(&ctx->rq_list)) { | |
1546 | list_splice_init(&ctx->rq_list, &tmp); | |
1547 | blk_mq_hctx_clear_pending(hctx, ctx); | |
1548 | } | |
1549 | spin_unlock(&ctx->lock); | |
1550 | ||
1551 | if (list_empty(&tmp)) | |
1552 | return NOTIFY_OK; | |
1553 | ||
1554 | ctx = blk_mq_get_ctx(q); | |
1555 | spin_lock(&ctx->lock); | |
1556 | ||
1557 | while (!list_empty(&tmp)) { | |
1558 | struct request *rq; | |
1559 | ||
1560 | rq = list_first_entry(&tmp, struct request, queuelist); | |
1561 | rq->mq_ctx = ctx; | |
1562 | list_move_tail(&rq->queuelist, &ctx->rq_list); | |
1563 | } | |
1564 | ||
1565 | hctx = q->mq_ops->map_queue(q, ctx->cpu); | |
1566 | blk_mq_hctx_mark_pending(hctx, ctx); | |
1567 | ||
1568 | spin_unlock(&ctx->lock); | |
1569 | ||
1570 | blk_mq_run_hw_queue(hctx, true); | |
1571 | blk_mq_put_ctx(ctx); | |
1572 | return NOTIFY_OK; | |
1573 | } | |
1574 | ||
1575 | static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx *hctx, int cpu) | |
1576 | { | |
1577 | struct request_queue *q = hctx->queue; | |
1578 | struct blk_mq_tag_set *set = q->tag_set; | |
1579 | ||
1580 | if (set->tags[hctx->queue_num]) | |
1581 | return NOTIFY_OK; | |
1582 | ||
1583 | set->tags[hctx->queue_num] = blk_mq_init_rq_map(set, hctx->queue_num); | |
1584 | if (!set->tags[hctx->queue_num]) | |
1585 | return NOTIFY_STOP; | |
1586 | ||
1587 | hctx->tags = set->tags[hctx->queue_num]; | |
1588 | return NOTIFY_OK; | |
1589 | } | |
1590 | ||
1591 | static int blk_mq_hctx_notify(void *data, unsigned long action, | |
1592 | unsigned int cpu) | |
1593 | { | |
1594 | struct blk_mq_hw_ctx *hctx = data; | |
1595 | ||
1596 | if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) | |
1597 | return blk_mq_hctx_cpu_offline(hctx, cpu); | |
1598 | else if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN) | |
1599 | return blk_mq_hctx_cpu_online(hctx, cpu); | |
1600 | ||
1601 | return NOTIFY_OK; | |
1602 | } | |
1603 | ||
1604 | static void blk_mq_exit_hctx(struct request_queue *q, | |
1605 | struct blk_mq_tag_set *set, | |
1606 | struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) | |
1607 | { | |
1608 | unsigned flush_start_tag = set->queue_depth; | |
1609 | ||
1610 | blk_mq_tag_idle(hctx); | |
1611 | ||
1612 | if (set->ops->exit_request) | |
1613 | set->ops->exit_request(set->driver_data, | |
1614 | hctx->fq->flush_rq, hctx_idx, | |
1615 | flush_start_tag + hctx_idx); | |
1616 | ||
1617 | if (set->ops->exit_hctx) | |
1618 | set->ops->exit_hctx(hctx, hctx_idx); | |
1619 | ||
1620 | blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); | |
1621 | blk_free_flush_queue(hctx->fq); | |
1622 | kfree(hctx->ctxs); | |
1623 | blk_mq_free_bitmap(&hctx->ctx_map); | |
1624 | } | |
1625 | ||
1626 | static void blk_mq_exit_hw_queues(struct request_queue *q, | |
1627 | struct blk_mq_tag_set *set, int nr_queue) | |
1628 | { | |
1629 | struct blk_mq_hw_ctx *hctx; | |
1630 | unsigned int i; | |
1631 | ||
1632 | queue_for_each_hw_ctx(q, hctx, i) { | |
1633 | if (i == nr_queue) | |
1634 | break; | |
1635 | blk_mq_exit_hctx(q, set, hctx, i); | |
1636 | } | |
1637 | } | |
1638 | ||
1639 | static void blk_mq_free_hw_queues(struct request_queue *q, | |
1640 | struct blk_mq_tag_set *set) | |
1641 | { | |
1642 | struct blk_mq_hw_ctx *hctx; | |
1643 | unsigned int i; | |
1644 | ||
1645 | queue_for_each_hw_ctx(q, hctx, i) | |
1646 | free_cpumask_var(hctx->cpumask); | |
1647 | } | |
1648 | ||
1649 | static int blk_mq_init_hctx(struct request_queue *q, | |
1650 | struct blk_mq_tag_set *set, | |
1651 | struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) | |
1652 | { | |
1653 | int node; | |
1654 | unsigned flush_start_tag = set->queue_depth; | |
1655 | ||
1656 | node = hctx->numa_node; | |
1657 | if (node == NUMA_NO_NODE) | |
1658 | node = hctx->numa_node = set->numa_node; | |
1659 | ||
1660 | INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); | |
1661 | INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn); | |
1662 | spin_lock_init(&hctx->lock); | |
1663 | INIT_LIST_HEAD(&hctx->dispatch); | |
1664 | hctx->queue = q; | |
1665 | hctx->queue_num = hctx_idx; | |
1666 | hctx->flags = set->flags; | |
1667 | ||
1668 | blk_mq_init_cpu_notifier(&hctx->cpu_notifier, | |
1669 | blk_mq_hctx_notify, hctx); | |
1670 | blk_mq_register_cpu_notifier(&hctx->cpu_notifier); | |
1671 | ||
1672 | hctx->tags = set->tags[hctx_idx]; | |
1673 | ||
1674 | /* | |
1675 | * Allocate space for all possible cpus to avoid allocation at | |
1676 | * runtime | |
1677 | */ | |
1678 | hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *), | |
1679 | GFP_KERNEL, node); | |
1680 | if (!hctx->ctxs) | |
1681 | goto unregister_cpu_notifier; | |
1682 | ||
1683 | if (blk_mq_alloc_bitmap(&hctx->ctx_map, node)) | |
1684 | goto free_ctxs; | |
1685 | ||
1686 | hctx->nr_ctx = 0; | |
1687 | ||
1688 | if (set->ops->init_hctx && | |
1689 | set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) | |
1690 | goto free_bitmap; | |
1691 | ||
1692 | hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size); | |
1693 | if (!hctx->fq) | |
1694 | goto exit_hctx; | |
1695 | ||
1696 | if (set->ops->init_request && | |
1697 | set->ops->init_request(set->driver_data, | |
1698 | hctx->fq->flush_rq, hctx_idx, | |
1699 | flush_start_tag + hctx_idx, node)) | |
1700 | goto free_fq; | |
1701 | ||
1702 | return 0; | |
1703 | ||
1704 | free_fq: | |
1705 | kfree(hctx->fq); | |
1706 | exit_hctx: | |
1707 | if (set->ops->exit_hctx) | |
1708 | set->ops->exit_hctx(hctx, hctx_idx); | |
1709 | free_bitmap: | |
1710 | blk_mq_free_bitmap(&hctx->ctx_map); | |
1711 | free_ctxs: | |
1712 | kfree(hctx->ctxs); | |
1713 | unregister_cpu_notifier: | |
1714 | blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); | |
1715 | ||
1716 | return -1; | |
1717 | } | |
1718 | ||
1719 | static int blk_mq_init_hw_queues(struct request_queue *q, | |
1720 | struct blk_mq_tag_set *set) | |
1721 | { | |
1722 | struct blk_mq_hw_ctx *hctx; | |
1723 | unsigned int i; | |
1724 | ||
1725 | /* | |
1726 | * Initialize hardware queues | |
1727 | */ | |
1728 | queue_for_each_hw_ctx(q, hctx, i) { | |
1729 | if (blk_mq_init_hctx(q, set, hctx, i)) | |
1730 | break; | |
1731 | } | |
1732 | ||
1733 | if (i == q->nr_hw_queues) | |
1734 | return 0; | |
1735 | ||
1736 | /* | |
1737 | * Init failed | |
1738 | */ | |
1739 | blk_mq_exit_hw_queues(q, set, i); | |
1740 | ||
1741 | return 1; | |
1742 | } | |
1743 | ||
1744 | static void blk_mq_init_cpu_queues(struct request_queue *q, | |
1745 | unsigned int nr_hw_queues) | |
1746 | { | |
1747 | unsigned int i; | |
1748 | ||
1749 | for_each_possible_cpu(i) { | |
1750 | struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); | |
1751 | struct blk_mq_hw_ctx *hctx; | |
1752 | ||
1753 | memset(__ctx, 0, sizeof(*__ctx)); | |
1754 | __ctx->cpu = i; | |
1755 | spin_lock_init(&__ctx->lock); | |
1756 | INIT_LIST_HEAD(&__ctx->rq_list); | |
1757 | __ctx->queue = q; | |
1758 | ||
1759 | /* If the cpu isn't online, the cpu is mapped to first hctx */ | |
1760 | if (!cpu_online(i)) | |
1761 | continue; | |
1762 | ||
1763 | hctx = q->mq_ops->map_queue(q, i); | |
1764 | cpumask_set_cpu(i, hctx->cpumask); | |
1765 | hctx->nr_ctx++; | |
1766 | ||
1767 | /* | |
1768 | * Set local node, IFF we have more than one hw queue. If | |
1769 | * not, we remain on the home node of the device | |
1770 | */ | |
1771 | if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) | |
1772 | hctx->numa_node = cpu_to_node(i); | |
1773 | } | |
1774 | } | |
1775 | ||
1776 | static void blk_mq_map_swqueue(struct request_queue *q) | |
1777 | { | |
1778 | unsigned int i; | |
1779 | struct blk_mq_hw_ctx *hctx; | |
1780 | struct blk_mq_ctx *ctx; | |
1781 | ||
1782 | queue_for_each_hw_ctx(q, hctx, i) { | |
1783 | cpumask_clear(hctx->cpumask); | |
1784 | hctx->nr_ctx = 0; | |
1785 | } | |
1786 | ||
1787 | /* | |
1788 | * Map software to hardware queues | |
1789 | */ | |
1790 | queue_for_each_ctx(q, ctx, i) { | |
1791 | /* If the cpu isn't online, the cpu is mapped to first hctx */ | |
1792 | if (!cpu_online(i)) | |
1793 | continue; | |
1794 | ||
1795 | hctx = q->mq_ops->map_queue(q, i); | |
1796 | cpumask_set_cpu(i, hctx->cpumask); | |
1797 | ctx->index_hw = hctx->nr_ctx; | |
1798 | hctx->ctxs[hctx->nr_ctx++] = ctx; | |
1799 | } | |
1800 | ||
1801 | queue_for_each_hw_ctx(q, hctx, i) { | |
1802 | /* | |
1803 | * If no software queues are mapped to this hardware queue, | |
1804 | * disable it and free the request entries. | |
1805 | */ | |
1806 | if (!hctx->nr_ctx) { | |
1807 | struct blk_mq_tag_set *set = q->tag_set; | |
1808 | ||
1809 | if (set->tags[i]) { | |
1810 | blk_mq_free_rq_map(set, set->tags[i], i); | |
1811 | set->tags[i] = NULL; | |
1812 | hctx->tags = NULL; | |
1813 | } | |
1814 | continue; | |
1815 | } | |
1816 | ||
1817 | /* | |
1818 | * Initialize batch roundrobin counts | |
1819 | */ | |
1820 | hctx->next_cpu = cpumask_first(hctx->cpumask); | |
1821 | hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; | |
1822 | } | |
1823 | } | |
1824 | ||
1825 | static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set) | |
1826 | { | |
1827 | struct blk_mq_hw_ctx *hctx; | |
1828 | struct request_queue *q; | |
1829 | bool shared; | |
1830 | int i; | |
1831 | ||
1832 | if (set->tag_list.next == set->tag_list.prev) | |
1833 | shared = false; | |
1834 | else | |
1835 | shared = true; | |
1836 | ||
1837 | list_for_each_entry(q, &set->tag_list, tag_set_list) { | |
1838 | blk_mq_freeze_queue(q); | |
1839 | ||
1840 | queue_for_each_hw_ctx(q, hctx, i) { | |
1841 | if (shared) | |
1842 | hctx->flags |= BLK_MQ_F_TAG_SHARED; | |
1843 | else | |
1844 | hctx->flags &= ~BLK_MQ_F_TAG_SHARED; | |
1845 | } | |
1846 | blk_mq_unfreeze_queue(q); | |
1847 | } | |
1848 | } | |
1849 | ||
1850 | static void blk_mq_del_queue_tag_set(struct request_queue *q) | |
1851 | { | |
1852 | struct blk_mq_tag_set *set = q->tag_set; | |
1853 | ||
1854 | mutex_lock(&set->tag_list_lock); | |
1855 | list_del_init(&q->tag_set_list); | |
1856 | blk_mq_update_tag_set_depth(set); | |
1857 | mutex_unlock(&set->tag_list_lock); | |
1858 | } | |
1859 | ||
1860 | static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, | |
1861 | struct request_queue *q) | |
1862 | { | |
1863 | q->tag_set = set; | |
1864 | ||
1865 | mutex_lock(&set->tag_list_lock); | |
1866 | list_add_tail(&q->tag_set_list, &set->tag_list); | |
1867 | blk_mq_update_tag_set_depth(set); | |
1868 | mutex_unlock(&set->tag_list_lock); | |
1869 | } | |
1870 | ||
1871 | /* | |
1872 | * It is the actual release handler for mq, but we do it from | |
1873 | * request queue's release handler for avoiding use-after-free | |
1874 | * and headache because q->mq_kobj shouldn't have been introduced, | |
1875 | * but we can't group ctx/kctx kobj without it. | |
1876 | */ | |
1877 | void blk_mq_release(struct request_queue *q) | |
1878 | { | |
1879 | struct blk_mq_hw_ctx *hctx; | |
1880 | unsigned int i; | |
1881 | ||
1882 | /* hctx kobj stays in hctx */ | |
1883 | queue_for_each_hw_ctx(q, hctx, i) | |
1884 | kfree(hctx); | |
1885 | ||
1886 | kfree(q->queue_hw_ctx); | |
1887 | ||
1888 | /* ctx kobj stays in queue_ctx */ | |
1889 | free_percpu(q->queue_ctx); | |
1890 | } | |
1891 | ||
1892 | struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) | |
1893 | { | |
1894 | struct request_queue *uninit_q, *q; | |
1895 | ||
1896 | uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node); | |
1897 | if (!uninit_q) | |
1898 | return ERR_PTR(-ENOMEM); | |
1899 | ||
1900 | q = blk_mq_init_allocated_queue(set, uninit_q); | |
1901 | if (IS_ERR(q)) | |
1902 | blk_cleanup_queue(uninit_q); | |
1903 | ||
1904 | return q; | |
1905 | } | |
1906 | EXPORT_SYMBOL(blk_mq_init_queue); | |
1907 | ||
1908 | struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, | |
1909 | struct request_queue *q) | |
1910 | { | |
1911 | struct blk_mq_hw_ctx **hctxs; | |
1912 | struct blk_mq_ctx __percpu *ctx; | |
1913 | unsigned int *map; | |
1914 | int i; | |
1915 | ||
1916 | ctx = alloc_percpu(struct blk_mq_ctx); | |
1917 | if (!ctx) | |
1918 | return ERR_PTR(-ENOMEM); | |
1919 | ||
1920 | hctxs = kmalloc_node(set->nr_hw_queues * sizeof(*hctxs), GFP_KERNEL, | |
1921 | set->numa_node); | |
1922 | ||
1923 | if (!hctxs) | |
1924 | goto err_percpu; | |
1925 | ||
1926 | map = blk_mq_make_queue_map(set); | |
1927 | if (!map) | |
1928 | goto err_map; | |
1929 | ||
1930 | for (i = 0; i < set->nr_hw_queues; i++) { | |
1931 | int node = blk_mq_hw_queue_to_node(map, i); | |
1932 | ||
1933 | hctxs[i] = kzalloc_node(sizeof(struct blk_mq_hw_ctx), | |
1934 | GFP_KERNEL, node); | |
1935 | if (!hctxs[i]) | |
1936 | goto err_hctxs; | |
1937 | ||
1938 | if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL, | |
1939 | node)) | |
1940 | goto err_hctxs; | |
1941 | ||
1942 | atomic_set(&hctxs[i]->nr_active, 0); | |
1943 | hctxs[i]->numa_node = node; | |
1944 | hctxs[i]->queue_num = i; | |
1945 | } | |
1946 | ||
1947 | /* | |
1948 | * Init percpu_ref in atomic mode so that it's faster to shutdown. | |
1949 | * See blk_register_queue() for details. | |
1950 | */ | |
1951 | if (percpu_ref_init(&q->mq_usage_counter, blk_mq_usage_counter_release, | |
1952 | PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) | |
1953 | goto err_hctxs; | |
1954 | ||
1955 | setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q); | |
1956 | blk_queue_rq_timeout(q, 30000); | |
1957 | ||
1958 | q->nr_queues = nr_cpu_ids; | |
1959 | q->nr_hw_queues = set->nr_hw_queues; | |
1960 | q->mq_map = map; | |
1961 | ||
1962 | q->queue_ctx = ctx; | |
1963 | q->queue_hw_ctx = hctxs; | |
1964 | ||
1965 | q->mq_ops = set->ops; | |
1966 | q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; | |
1967 | ||
1968 | if (!(set->flags & BLK_MQ_F_SG_MERGE)) | |
1969 | q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE; | |
1970 | ||
1971 | q->sg_reserved_size = INT_MAX; | |
1972 | ||
1973 | INIT_WORK(&q->requeue_work, blk_mq_requeue_work); | |
1974 | INIT_LIST_HEAD(&q->requeue_list); | |
1975 | spin_lock_init(&q->requeue_lock); | |
1976 | ||
1977 | if (q->nr_hw_queues > 1) | |
1978 | blk_queue_make_request(q, blk_mq_make_request); | |
1979 | else | |
1980 | blk_queue_make_request(q, blk_sq_make_request); | |
1981 | ||
1982 | if (set->timeout) | |
1983 | blk_queue_rq_timeout(q, set->timeout); | |
1984 | ||
1985 | /* | |
1986 | * Do this after blk_queue_make_request() overrides it... | |
1987 | */ | |
1988 | q->nr_requests = set->queue_depth; | |
1989 | ||
1990 | if (set->ops->complete) | |
1991 | blk_queue_softirq_done(q, set->ops->complete); | |
1992 | ||
1993 | blk_mq_init_cpu_queues(q, set->nr_hw_queues); | |
1994 | ||
1995 | if (blk_mq_init_hw_queues(q, set)) | |
1996 | goto err_hctxs; | |
1997 | ||
1998 | mutex_lock(&all_q_mutex); | |
1999 | list_add_tail(&q->all_q_node, &all_q_list); | |
2000 | mutex_unlock(&all_q_mutex); | |
2001 | ||
2002 | blk_mq_add_queue_tag_set(set, q); | |
2003 | ||
2004 | blk_mq_map_swqueue(q); | |
2005 | ||
2006 | return q; | |
2007 | ||
2008 | err_hctxs: | |
2009 | kfree(map); | |
2010 | for (i = 0; i < set->nr_hw_queues; i++) { | |
2011 | if (!hctxs[i]) | |
2012 | break; | |
2013 | free_cpumask_var(hctxs[i]->cpumask); | |
2014 | kfree(hctxs[i]); | |
2015 | } | |
2016 | err_map: | |
2017 | kfree(hctxs); | |
2018 | err_percpu: | |
2019 | free_percpu(ctx); | |
2020 | return ERR_PTR(-ENOMEM); | |
2021 | } | |
2022 | EXPORT_SYMBOL(blk_mq_init_allocated_queue); | |
2023 | ||
2024 | void blk_mq_free_queue(struct request_queue *q) | |
2025 | { | |
2026 | struct blk_mq_tag_set *set = q->tag_set; | |
2027 | ||
2028 | blk_mq_del_queue_tag_set(q); | |
2029 | ||
2030 | blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); | |
2031 | blk_mq_free_hw_queues(q, set); | |
2032 | ||
2033 | percpu_ref_exit(&q->mq_usage_counter); | |
2034 | ||
2035 | kfree(q->mq_map); | |
2036 | ||
2037 | q->mq_map = NULL; | |
2038 | ||
2039 | mutex_lock(&all_q_mutex); | |
2040 | list_del_init(&q->all_q_node); | |
2041 | mutex_unlock(&all_q_mutex); | |
2042 | } | |
2043 | ||
2044 | /* Basically redo blk_mq_init_queue with queue frozen */ | |
2045 | static void blk_mq_queue_reinit(struct request_queue *q) | |
2046 | { | |
2047 | WARN_ON_ONCE(!q->mq_freeze_depth); | |
2048 | ||
2049 | blk_mq_sysfs_unregister(q); | |
2050 | ||
2051 | blk_mq_update_queue_map(q->mq_map, q->nr_hw_queues); | |
2052 | ||
2053 | /* | |
2054 | * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe | |
2055 | * we should change hctx numa_node according to new topology (this | |
2056 | * involves free and re-allocate memory, worthy doing?) | |
2057 | */ | |
2058 | ||
2059 | blk_mq_map_swqueue(q); | |
2060 | ||
2061 | blk_mq_sysfs_register(q); | |
2062 | } | |
2063 | ||
2064 | static int blk_mq_queue_reinit_notify(struct notifier_block *nb, | |
2065 | unsigned long action, void *hcpu) | |
2066 | { | |
2067 | struct request_queue *q; | |
2068 | ||
2069 | /* | |
2070 | * Before new mappings are established, hotadded cpu might already | |
2071 | * start handling requests. This doesn't break anything as we map | |
2072 | * offline CPUs to first hardware queue. We will re-init the queue | |
2073 | * below to get optimal settings. | |
2074 | */ | |
2075 | if (action != CPU_DEAD && action != CPU_DEAD_FROZEN && | |
2076 | action != CPU_ONLINE && action != CPU_ONLINE_FROZEN) | |
2077 | return NOTIFY_OK; | |
2078 | ||
2079 | mutex_lock(&all_q_mutex); | |
2080 | ||
2081 | /* | |
2082 | * We need to freeze and reinit all existing queues. Freezing | |
2083 | * involves synchronous wait for an RCU grace period and doing it | |
2084 | * one by one may take a long time. Start freezing all queues in | |
2085 | * one swoop and then wait for the completions so that freezing can | |
2086 | * take place in parallel. | |
2087 | */ | |
2088 | list_for_each_entry(q, &all_q_list, all_q_node) | |
2089 | blk_mq_freeze_queue_start(q); | |
2090 | list_for_each_entry(q, &all_q_list, all_q_node) | |
2091 | blk_mq_freeze_queue_wait(q); | |
2092 | ||
2093 | list_for_each_entry(q, &all_q_list, all_q_node) | |
2094 | blk_mq_queue_reinit(q); | |
2095 | ||
2096 | list_for_each_entry(q, &all_q_list, all_q_node) | |
2097 | blk_mq_unfreeze_queue(q); | |
2098 | ||
2099 | mutex_unlock(&all_q_mutex); | |
2100 | return NOTIFY_OK; | |
2101 | } | |
2102 | ||
2103 | static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) | |
2104 | { | |
2105 | int i; | |
2106 | ||
2107 | for (i = 0; i < set->nr_hw_queues; i++) { | |
2108 | set->tags[i] = blk_mq_init_rq_map(set, i); | |
2109 | if (!set->tags[i]) | |
2110 | goto out_unwind; | |
2111 | } | |
2112 | ||
2113 | return 0; | |
2114 | ||
2115 | out_unwind: | |
2116 | while (--i >= 0) | |
2117 | blk_mq_free_rq_map(set, set->tags[i], i); | |
2118 | ||
2119 | return -ENOMEM; | |
2120 | } | |
2121 | ||
2122 | /* | |
2123 | * Allocate the request maps associated with this tag_set. Note that this | |
2124 | * may reduce the depth asked for, if memory is tight. set->queue_depth | |
2125 | * will be updated to reflect the allocated depth. | |
2126 | */ | |
2127 | static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) | |
2128 | { | |
2129 | unsigned int depth; | |
2130 | int err; | |
2131 | ||
2132 | depth = set->queue_depth; | |
2133 | do { | |
2134 | err = __blk_mq_alloc_rq_maps(set); | |
2135 | if (!err) | |
2136 | break; | |
2137 | ||
2138 | set->queue_depth >>= 1; | |
2139 | if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { | |
2140 | err = -ENOMEM; | |
2141 | break; | |
2142 | } | |
2143 | } while (set->queue_depth); | |
2144 | ||
2145 | if (!set->queue_depth || err) { | |
2146 | pr_err("blk-mq: failed to allocate request map\n"); | |
2147 | return -ENOMEM; | |
2148 | } | |
2149 | ||
2150 | if (depth != set->queue_depth) | |
2151 | pr_info("blk-mq: reduced tag depth (%u -> %u)\n", | |
2152 | depth, set->queue_depth); | |
2153 | ||
2154 | return 0; | |
2155 | } | |
2156 | ||
2157 | /* | |
2158 | * Alloc a tag set to be associated with one or more request queues. | |
2159 | * May fail with EINVAL for various error conditions. May adjust the | |
2160 | * requested depth down, if if it too large. In that case, the set | |
2161 | * value will be stored in set->queue_depth. | |
2162 | */ | |
2163 | int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) | |
2164 | { | |
2165 | BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); | |
2166 | ||
2167 | if (!set->nr_hw_queues) | |
2168 | return -EINVAL; | |
2169 | if (!set->queue_depth) | |
2170 | return -EINVAL; | |
2171 | if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) | |
2172 | return -EINVAL; | |
2173 | ||
2174 | if (!set->nr_hw_queues || !set->ops->queue_rq || !set->ops->map_queue) | |
2175 | return -EINVAL; | |
2176 | ||
2177 | if (set->queue_depth > BLK_MQ_MAX_DEPTH) { | |
2178 | pr_info("blk-mq: reduced tag depth to %u\n", | |
2179 | BLK_MQ_MAX_DEPTH); | |
2180 | set->queue_depth = BLK_MQ_MAX_DEPTH; | |
2181 | } | |
2182 | ||
2183 | /* | |
2184 | * If a crashdump is active, then we are potentially in a very | |
2185 | * memory constrained environment. Limit us to 1 queue and | |
2186 | * 64 tags to prevent using too much memory. | |
2187 | */ | |
2188 | if (is_kdump_kernel()) { | |
2189 | set->nr_hw_queues = 1; | |
2190 | set->queue_depth = min(64U, set->queue_depth); | |
2191 | } | |
2192 | ||
2193 | set->tags = kmalloc_node(set->nr_hw_queues * | |
2194 | sizeof(struct blk_mq_tags *), | |
2195 | GFP_KERNEL, set->numa_node); | |
2196 | if (!set->tags) | |
2197 | return -ENOMEM; | |
2198 | ||
2199 | if (blk_mq_alloc_rq_maps(set)) | |
2200 | goto enomem; | |
2201 | ||
2202 | mutex_init(&set->tag_list_lock); | |
2203 | INIT_LIST_HEAD(&set->tag_list); | |
2204 | ||
2205 | return 0; | |
2206 | enomem: | |
2207 | kfree(set->tags); | |
2208 | set->tags = NULL; | |
2209 | return -ENOMEM; | |
2210 | } | |
2211 | EXPORT_SYMBOL(blk_mq_alloc_tag_set); | |
2212 | ||
2213 | void blk_mq_free_tag_set(struct blk_mq_tag_set *set) | |
2214 | { | |
2215 | int i; | |
2216 | ||
2217 | for (i = 0; i < set->nr_hw_queues; i++) { | |
2218 | if (set->tags[i]) | |
2219 | blk_mq_free_rq_map(set, set->tags[i], i); | |
2220 | } | |
2221 | ||
2222 | kfree(set->tags); | |
2223 | set->tags = NULL; | |
2224 | } | |
2225 | EXPORT_SYMBOL(blk_mq_free_tag_set); | |
2226 | ||
2227 | int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) | |
2228 | { | |
2229 | struct blk_mq_tag_set *set = q->tag_set; | |
2230 | struct blk_mq_hw_ctx *hctx; | |
2231 | int i, ret; | |
2232 | ||
2233 | if (!set || nr > set->queue_depth) | |
2234 | return -EINVAL; | |
2235 | ||
2236 | ret = 0; | |
2237 | queue_for_each_hw_ctx(q, hctx, i) { | |
2238 | ret = blk_mq_tag_update_depth(hctx->tags, nr); | |
2239 | if (ret) | |
2240 | break; | |
2241 | } | |
2242 | ||
2243 | if (!ret) | |
2244 | q->nr_requests = nr; | |
2245 | ||
2246 | return ret; | |
2247 | } | |
2248 | ||
2249 | void blk_mq_disable_hotplug(void) | |
2250 | { | |
2251 | mutex_lock(&all_q_mutex); | |
2252 | } | |
2253 | ||
2254 | void blk_mq_enable_hotplug(void) | |
2255 | { | |
2256 | mutex_unlock(&all_q_mutex); | |
2257 | } | |
2258 | ||
2259 | static int __init blk_mq_init(void) | |
2260 | { | |
2261 | blk_mq_cpu_init(); | |
2262 | ||
2263 | hotcpu_notifier(blk_mq_queue_reinit_notify, 0); | |
2264 | ||
2265 | return 0; | |
2266 | } | |
2267 | subsys_initcall(blk_mq_init); |