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4cc96131 MS |
1 | /* |
2 | * Copyright (C) 2016 Red Hat, Inc. All rights reserved. | |
3 | * | |
4 | * This file is released under the GPL. | |
5 | */ | |
6 | ||
7 | #include "dm-core.h" | |
8 | #include "dm-rq.h" | |
9 | ||
10 | #include <linux/elevator.h> /* for rq_end_sector() */ | |
11 | #include <linux/blk-mq.h> | |
12 | ||
13 | #define DM_MSG_PREFIX "core-rq" | |
14 | ||
15 | #define DM_MQ_NR_HW_QUEUES 1 | |
16 | #define DM_MQ_QUEUE_DEPTH 2048 | |
17 | static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES; | |
18 | static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH; | |
19 | ||
20 | /* | |
21 | * Request-based DM's mempools' reserved IOs set by the user. | |
22 | */ | |
23 | #define RESERVED_REQUEST_BASED_IOS 256 | |
24 | static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS; | |
25 | ||
26 | #ifdef CONFIG_DM_MQ_DEFAULT | |
27 | static bool use_blk_mq = true; | |
28 | #else | |
29 | static bool use_blk_mq = false; | |
30 | #endif | |
31 | ||
32 | bool dm_use_blk_mq_default(void) | |
33 | { | |
34 | return use_blk_mq; | |
35 | } | |
36 | ||
37 | bool dm_use_blk_mq(struct mapped_device *md) | |
38 | { | |
39 | return md->use_blk_mq; | |
40 | } | |
41 | EXPORT_SYMBOL_GPL(dm_use_blk_mq); | |
42 | ||
43 | unsigned dm_get_reserved_rq_based_ios(void) | |
44 | { | |
45 | return __dm_get_module_param(&reserved_rq_based_ios, | |
46 | RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS); | |
47 | } | |
48 | EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios); | |
49 | ||
50 | static unsigned dm_get_blk_mq_nr_hw_queues(void) | |
51 | { | |
52 | return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32); | |
53 | } | |
54 | ||
55 | static unsigned dm_get_blk_mq_queue_depth(void) | |
56 | { | |
57 | return __dm_get_module_param(&dm_mq_queue_depth, | |
58 | DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH); | |
59 | } | |
60 | ||
61 | int dm_request_based(struct mapped_device *md) | |
62 | { | |
63 | return blk_queue_stackable(md->queue); | |
64 | } | |
65 | ||
66 | static void dm_old_start_queue(struct request_queue *q) | |
67 | { | |
68 | unsigned long flags; | |
69 | ||
70 | spin_lock_irqsave(q->queue_lock, flags); | |
71 | if (blk_queue_stopped(q)) | |
72 | blk_start_queue(q); | |
73 | spin_unlock_irqrestore(q->queue_lock, flags); | |
74 | } | |
75 | ||
9dbeaeab MS |
76 | static void dm_mq_start_queue(struct request_queue *q) |
77 | { | |
78 | unsigned long flags; | |
79 | ||
80 | spin_lock_irqsave(q->queue_lock, flags); | |
81 | queue_flag_clear(QUEUE_FLAG_STOPPED, q); | |
82 | spin_unlock_irqrestore(q->queue_lock, flags); | |
83 | ||
84 | blk_mq_start_stopped_hw_queues(q, true); | |
85 | blk_mq_kick_requeue_list(q); | |
86 | } | |
87 | ||
4cc96131 MS |
88 | void dm_start_queue(struct request_queue *q) |
89 | { | |
90 | if (!q->mq_ops) | |
91 | dm_old_start_queue(q); | |
9dbeaeab MS |
92 | else |
93 | dm_mq_start_queue(q); | |
4cc96131 MS |
94 | } |
95 | ||
96 | static void dm_old_stop_queue(struct request_queue *q) | |
97 | { | |
98 | unsigned long flags; | |
99 | ||
100 | spin_lock_irqsave(q->queue_lock, flags); | |
c533f249 BVA |
101 | if (!blk_queue_stopped(q)) |
102 | blk_stop_queue(q); | |
4cc96131 MS |
103 | spin_unlock_irqrestore(q->queue_lock, flags); |
104 | } | |
105 | ||
2397a15a BVA |
106 | static void dm_mq_stop_queue(struct request_queue *q) |
107 | { | |
108 | unsigned long flags; | |
109 | ||
110 | spin_lock_irqsave(q->queue_lock, flags); | |
111 | if (blk_queue_stopped(q)) { | |
112 | spin_unlock_irqrestore(q->queue_lock, flags); | |
113 | return; | |
114 | } | |
115 | ||
116 | queue_flag_set(QUEUE_FLAG_STOPPED, q); | |
117 | spin_unlock_irqrestore(q->queue_lock, flags); | |
118 | ||
119 | /* Avoid that requeuing could restart the queue. */ | |
120 | blk_mq_cancel_requeue_work(q); | |
121 | blk_mq_stop_hw_queues(q); | |
122 | } | |
123 | ||
4cc96131 MS |
124 | void dm_stop_queue(struct request_queue *q) |
125 | { | |
126 | if (!q->mq_ops) | |
127 | dm_old_stop_queue(q); | |
2397a15a BVA |
128 | else |
129 | dm_mq_stop_queue(q); | |
4cc96131 MS |
130 | } |
131 | ||
132 | static struct dm_rq_target_io *alloc_old_rq_tio(struct mapped_device *md, | |
133 | gfp_t gfp_mask) | |
134 | { | |
135 | return mempool_alloc(md->io_pool, gfp_mask); | |
136 | } | |
137 | ||
138 | static void free_old_rq_tio(struct dm_rq_target_io *tio) | |
139 | { | |
140 | mempool_free(tio, tio->md->io_pool); | |
141 | } | |
142 | ||
143 | static struct request *alloc_old_clone_request(struct mapped_device *md, | |
144 | gfp_t gfp_mask) | |
145 | { | |
146 | return mempool_alloc(md->rq_pool, gfp_mask); | |
147 | } | |
148 | ||
149 | static void free_old_clone_request(struct mapped_device *md, struct request *rq) | |
150 | { | |
151 | mempool_free(rq, md->rq_pool); | |
152 | } | |
153 | ||
154 | /* | |
155 | * Partial completion handling for request-based dm | |
156 | */ | |
157 | static void end_clone_bio(struct bio *clone) | |
158 | { | |
159 | struct dm_rq_clone_bio_info *info = | |
160 | container_of(clone, struct dm_rq_clone_bio_info, clone); | |
161 | struct dm_rq_target_io *tio = info->tio; | |
162 | struct bio *bio = info->orig; | |
163 | unsigned int nr_bytes = info->orig->bi_iter.bi_size; | |
164 | int error = clone->bi_error; | |
165 | ||
166 | bio_put(clone); | |
167 | ||
168 | if (tio->error) | |
169 | /* | |
170 | * An error has already been detected on the request. | |
171 | * Once error occurred, just let clone->end_io() handle | |
172 | * the remainder. | |
173 | */ | |
174 | return; | |
175 | else if (error) { | |
176 | /* | |
177 | * Don't notice the error to the upper layer yet. | |
178 | * The error handling decision is made by the target driver, | |
179 | * when the request is completed. | |
180 | */ | |
181 | tio->error = error; | |
182 | return; | |
183 | } | |
184 | ||
185 | /* | |
186 | * I/O for the bio successfully completed. | |
187 | * Notice the data completion to the upper layer. | |
188 | */ | |
189 | ||
190 | /* | |
191 | * bios are processed from the head of the list. | |
192 | * So the completing bio should always be rq->bio. | |
193 | * If it's not, something wrong is happening. | |
194 | */ | |
195 | if (tio->orig->bio != bio) | |
196 | DMERR("bio completion is going in the middle of the request"); | |
197 | ||
198 | /* | |
199 | * Update the original request. | |
200 | * Do not use blk_end_request() here, because it may complete | |
201 | * the original request before the clone, and break the ordering. | |
202 | */ | |
203 | blk_update_request(tio->orig, 0, nr_bytes); | |
204 | } | |
205 | ||
206 | static struct dm_rq_target_io *tio_from_request(struct request *rq) | |
207 | { | |
208 | return (rq->q->mq_ops ? blk_mq_rq_to_pdu(rq) : rq->special); | |
209 | } | |
210 | ||
211 | static void rq_end_stats(struct mapped_device *md, struct request *orig) | |
212 | { | |
213 | if (unlikely(dm_stats_used(&md->stats))) { | |
214 | struct dm_rq_target_io *tio = tio_from_request(orig); | |
215 | tio->duration_jiffies = jiffies - tio->duration_jiffies; | |
216 | dm_stats_account_io(&md->stats, rq_data_dir(orig), | |
217 | blk_rq_pos(orig), tio->n_sectors, true, | |
218 | tio->duration_jiffies, &tio->stats_aux); | |
219 | } | |
220 | } | |
221 | ||
222 | /* | |
223 | * Don't touch any member of the md after calling this function because | |
224 | * the md may be freed in dm_put() at the end of this function. | |
225 | * Or do dm_get() before calling this function and dm_put() later. | |
226 | */ | |
227 | static void rq_completed(struct mapped_device *md, int rw, bool run_queue) | |
228 | { | |
229 | atomic_dec(&md->pending[rw]); | |
230 | ||
231 | /* nudge anyone waiting on suspend queue */ | |
232 | if (!md_in_flight(md)) | |
233 | wake_up(&md->wait); | |
234 | ||
235 | /* | |
236 | * Run this off this callpath, as drivers could invoke end_io while | |
237 | * inside their request_fn (and holding the queue lock). Calling | |
238 | * back into ->request_fn() could deadlock attempting to grab the | |
239 | * queue lock again. | |
240 | */ | |
241 | if (!md->queue->mq_ops && run_queue) | |
242 | blk_run_queue_async(md->queue); | |
243 | ||
244 | /* | |
245 | * dm_put() must be at the end of this function. See the comment above | |
246 | */ | |
247 | dm_put(md); | |
248 | } | |
249 | ||
250 | static void free_rq_clone(struct request *clone) | |
251 | { | |
252 | struct dm_rq_target_io *tio = clone->end_io_data; | |
253 | struct mapped_device *md = tio->md; | |
254 | ||
255 | blk_rq_unprep_clone(clone); | |
256 | ||
e83068a5 MS |
257 | /* |
258 | * It is possible for a clone_old_rq() allocated clone to | |
259 | * get passed in -- it may not yet have a request_queue. | |
260 | * This is known to occur if the error target replaces | |
261 | * a multipath target that has a request_fn queue stacked | |
262 | * on blk-mq queue(s). | |
263 | */ | |
264 | if (clone->q && clone->q->mq_ops) | |
4cc96131 MS |
265 | /* stacked on blk-mq queue(s) */ |
266 | tio->ti->type->release_clone_rq(clone); | |
267 | else if (!md->queue->mq_ops) | |
268 | /* request_fn queue stacked on request_fn queue(s) */ | |
269 | free_old_clone_request(md, clone); | |
270 | ||
271 | if (!md->queue->mq_ops) | |
272 | free_old_rq_tio(tio); | |
273 | } | |
274 | ||
275 | /* | |
276 | * Complete the clone and the original request. | |
277 | * Must be called without clone's queue lock held, | |
278 | * see end_clone_request() for more details. | |
279 | */ | |
280 | static void dm_end_request(struct request *clone, int error) | |
281 | { | |
282 | int rw = rq_data_dir(clone); | |
283 | struct dm_rq_target_io *tio = clone->end_io_data; | |
284 | struct mapped_device *md = tio->md; | |
285 | struct request *rq = tio->orig; | |
286 | ||
287 | if (rq->cmd_type == REQ_TYPE_BLOCK_PC) { | |
288 | rq->errors = clone->errors; | |
289 | rq->resid_len = clone->resid_len; | |
290 | ||
291 | if (rq->sense) | |
292 | /* | |
293 | * We are using the sense buffer of the original | |
294 | * request. | |
295 | * So setting the length of the sense data is enough. | |
296 | */ | |
297 | rq->sense_len = clone->sense_len; | |
298 | } | |
299 | ||
300 | free_rq_clone(clone); | |
301 | rq_end_stats(md, rq); | |
302 | if (!rq->q->mq_ops) | |
303 | blk_end_request_all(rq, error); | |
304 | else | |
305 | blk_mq_end_request(rq, error); | |
306 | rq_completed(md, rw, true); | |
307 | } | |
308 | ||
309 | static void dm_unprep_request(struct request *rq) | |
310 | { | |
311 | struct dm_rq_target_io *tio = tio_from_request(rq); | |
312 | struct request *clone = tio->clone; | |
313 | ||
314 | if (!rq->q->mq_ops) { | |
315 | rq->special = NULL; | |
316 | rq->cmd_flags &= ~REQ_DONTPREP; | |
317 | } | |
318 | ||
319 | if (clone) | |
320 | free_rq_clone(clone); | |
321 | else if (!tio->md->queue->mq_ops) | |
322 | free_old_rq_tio(tio); | |
323 | } | |
324 | ||
325 | /* | |
326 | * Requeue the original request of a clone. | |
327 | */ | |
328 | static void dm_old_requeue_request(struct request *rq) | |
329 | { | |
330 | struct request_queue *q = rq->q; | |
331 | unsigned long flags; | |
332 | ||
333 | spin_lock_irqsave(q->queue_lock, flags); | |
334 | blk_requeue_request(q, rq); | |
335 | blk_run_queue_async(q); | |
336 | spin_unlock_irqrestore(q->queue_lock, flags); | |
337 | } | |
338 | ||
339 | static void dm_mq_requeue_request(struct request *rq) | |
340 | { | |
341 | struct request_queue *q = rq->q; | |
342 | unsigned long flags; | |
343 | ||
344 | blk_mq_requeue_request(rq); | |
345 | spin_lock_irqsave(q->queue_lock, flags); | |
346 | if (!blk_queue_stopped(q)) | |
347 | blk_mq_kick_requeue_list(q); | |
348 | spin_unlock_irqrestore(q->queue_lock, flags); | |
349 | } | |
350 | ||
351 | static void dm_requeue_original_request(struct mapped_device *md, | |
352 | struct request *rq) | |
353 | { | |
354 | int rw = rq_data_dir(rq); | |
355 | ||
356 | rq_end_stats(md, rq); | |
357 | dm_unprep_request(rq); | |
358 | ||
359 | if (!rq->q->mq_ops) | |
360 | dm_old_requeue_request(rq); | |
361 | else | |
362 | dm_mq_requeue_request(rq); | |
363 | ||
364 | rq_completed(md, rw, false); | |
365 | } | |
366 | ||
367 | static void dm_done(struct request *clone, int error, bool mapped) | |
368 | { | |
369 | int r = error; | |
370 | struct dm_rq_target_io *tio = clone->end_io_data; | |
371 | dm_request_endio_fn rq_end_io = NULL; | |
372 | ||
373 | if (tio->ti) { | |
374 | rq_end_io = tio->ti->type->rq_end_io; | |
375 | ||
376 | if (mapped && rq_end_io) | |
377 | r = rq_end_io(tio->ti, clone, error, &tio->info); | |
378 | } | |
379 | ||
380 | if (unlikely(r == -EREMOTEIO && (req_op(clone) == REQ_OP_WRITE_SAME) && | |
381 | !clone->q->limits.max_write_same_sectors)) | |
382 | disable_write_same(tio->md); | |
383 | ||
384 | if (r <= 0) | |
385 | /* The target wants to complete the I/O */ | |
386 | dm_end_request(clone, r); | |
387 | else if (r == DM_ENDIO_INCOMPLETE) | |
388 | /* The target will handle the I/O */ | |
389 | return; | |
390 | else if (r == DM_ENDIO_REQUEUE) | |
391 | /* The target wants to requeue the I/O */ | |
392 | dm_requeue_original_request(tio->md, tio->orig); | |
393 | else { | |
394 | DMWARN("unimplemented target endio return value: %d", r); | |
395 | BUG(); | |
396 | } | |
397 | } | |
398 | ||
399 | /* | |
400 | * Request completion handler for request-based dm | |
401 | */ | |
402 | static void dm_softirq_done(struct request *rq) | |
403 | { | |
404 | bool mapped = true; | |
405 | struct dm_rq_target_io *tio = tio_from_request(rq); | |
406 | struct request *clone = tio->clone; | |
407 | int rw; | |
408 | ||
409 | if (!clone) { | |
410 | rq_end_stats(tio->md, rq); | |
411 | rw = rq_data_dir(rq); | |
412 | if (!rq->q->mq_ops) { | |
413 | blk_end_request_all(rq, tio->error); | |
414 | rq_completed(tio->md, rw, false); | |
415 | free_old_rq_tio(tio); | |
416 | } else { | |
417 | blk_mq_end_request(rq, tio->error); | |
418 | rq_completed(tio->md, rw, false); | |
419 | } | |
420 | return; | |
421 | } | |
422 | ||
423 | if (rq->cmd_flags & REQ_FAILED) | |
424 | mapped = false; | |
425 | ||
426 | dm_done(clone, tio->error, mapped); | |
427 | } | |
428 | ||
429 | /* | |
430 | * Complete the clone and the original request with the error status | |
431 | * through softirq context. | |
432 | */ | |
433 | static void dm_complete_request(struct request *rq, int error) | |
434 | { | |
435 | struct dm_rq_target_io *tio = tio_from_request(rq); | |
436 | ||
437 | tio->error = error; | |
438 | if (!rq->q->mq_ops) | |
439 | blk_complete_request(rq); | |
440 | else | |
441 | blk_mq_complete_request(rq, error); | |
442 | } | |
443 | ||
444 | /* | |
445 | * Complete the not-mapped clone and the original request with the error status | |
446 | * through softirq context. | |
447 | * Target's rq_end_io() function isn't called. | |
448 | * This may be used when the target's map_rq() or clone_and_map_rq() functions fail. | |
449 | */ | |
450 | static void dm_kill_unmapped_request(struct request *rq, int error) | |
451 | { | |
452 | rq->cmd_flags |= REQ_FAILED; | |
453 | dm_complete_request(rq, error); | |
454 | } | |
455 | ||
456 | /* | |
457 | * Called with the clone's queue lock held (in the case of .request_fn) | |
458 | */ | |
459 | static void end_clone_request(struct request *clone, int error) | |
460 | { | |
461 | struct dm_rq_target_io *tio = clone->end_io_data; | |
462 | ||
463 | if (!clone->q->mq_ops) { | |
464 | /* | |
465 | * For just cleaning up the information of the queue in which | |
466 | * the clone was dispatched. | |
467 | * The clone is *NOT* freed actually here because it is alloced | |
468 | * from dm own mempool (REQ_ALLOCED isn't set). | |
469 | */ | |
470 | __blk_put_request(clone->q, clone); | |
471 | } | |
472 | ||
473 | /* | |
474 | * Actual request completion is done in a softirq context which doesn't | |
475 | * hold the clone's queue lock. Otherwise, deadlock could occur because: | |
476 | * - another request may be submitted by the upper level driver | |
477 | * of the stacking during the completion | |
478 | * - the submission which requires queue lock may be done | |
479 | * against this clone's queue | |
480 | */ | |
481 | dm_complete_request(tio->orig, error); | |
482 | } | |
483 | ||
484 | static void dm_dispatch_clone_request(struct request *clone, struct request *rq) | |
485 | { | |
486 | int r; | |
487 | ||
488 | if (blk_queue_io_stat(clone->q)) | |
489 | clone->cmd_flags |= REQ_IO_STAT; | |
490 | ||
491 | clone->start_time = jiffies; | |
492 | r = blk_insert_cloned_request(clone->q, clone); | |
493 | if (r) | |
494 | /* must complete clone in terms of original request */ | |
495 | dm_complete_request(rq, r); | |
496 | } | |
497 | ||
498 | static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig, | |
499 | void *data) | |
500 | { | |
501 | struct dm_rq_target_io *tio = data; | |
502 | struct dm_rq_clone_bio_info *info = | |
503 | container_of(bio, struct dm_rq_clone_bio_info, clone); | |
504 | ||
505 | info->orig = bio_orig; | |
506 | info->tio = tio; | |
507 | bio->bi_end_io = end_clone_bio; | |
508 | ||
509 | return 0; | |
510 | } | |
511 | ||
512 | static int setup_clone(struct request *clone, struct request *rq, | |
513 | struct dm_rq_target_io *tio, gfp_t gfp_mask) | |
514 | { | |
515 | int r; | |
516 | ||
517 | r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask, | |
518 | dm_rq_bio_constructor, tio); | |
519 | if (r) | |
520 | return r; | |
521 | ||
522 | clone->cmd = rq->cmd; | |
523 | clone->cmd_len = rq->cmd_len; | |
524 | clone->sense = rq->sense; | |
525 | clone->end_io = end_clone_request; | |
526 | clone->end_io_data = tio; | |
527 | ||
528 | tio->clone = clone; | |
529 | ||
530 | return 0; | |
531 | } | |
532 | ||
533 | static struct request *clone_old_rq(struct request *rq, struct mapped_device *md, | |
534 | struct dm_rq_target_io *tio, gfp_t gfp_mask) | |
535 | { | |
536 | /* | |
537 | * Create clone for use with .request_fn request_queue | |
538 | */ | |
539 | struct request *clone; | |
540 | ||
541 | clone = alloc_old_clone_request(md, gfp_mask); | |
542 | if (!clone) | |
543 | return NULL; | |
544 | ||
545 | blk_rq_init(NULL, clone); | |
546 | if (setup_clone(clone, rq, tio, gfp_mask)) { | |
547 | /* -ENOMEM */ | |
548 | free_old_clone_request(md, clone); | |
549 | return NULL; | |
550 | } | |
551 | ||
552 | return clone; | |
553 | } | |
554 | ||
555 | static void map_tio_request(struct kthread_work *work); | |
556 | ||
557 | static void init_tio(struct dm_rq_target_io *tio, struct request *rq, | |
558 | struct mapped_device *md) | |
559 | { | |
560 | tio->md = md; | |
561 | tio->ti = NULL; | |
562 | tio->clone = NULL; | |
563 | tio->orig = rq; | |
564 | tio->error = 0; | |
565 | /* | |
566 | * Avoid initializing info for blk-mq; it passes | |
567 | * target-specific data through info.ptr | |
568 | * (see: dm_mq_init_request) | |
569 | */ | |
570 | if (!md->init_tio_pdu) | |
571 | memset(&tio->info, 0, sizeof(tio->info)); | |
572 | if (md->kworker_task) | |
573 | init_kthread_work(&tio->work, map_tio_request); | |
574 | } | |
575 | ||
576 | static struct dm_rq_target_io *dm_old_prep_tio(struct request *rq, | |
577 | struct mapped_device *md, | |
578 | gfp_t gfp_mask) | |
579 | { | |
580 | struct dm_rq_target_io *tio; | |
581 | int srcu_idx; | |
582 | struct dm_table *table; | |
583 | ||
584 | tio = alloc_old_rq_tio(md, gfp_mask); | |
585 | if (!tio) | |
586 | return NULL; | |
587 | ||
588 | init_tio(tio, rq, md); | |
589 | ||
590 | table = dm_get_live_table(md, &srcu_idx); | |
591 | /* | |
592 | * Must clone a request if this .request_fn DM device | |
593 | * is stacked on .request_fn device(s). | |
594 | */ | |
e83068a5 | 595 | if (!dm_table_all_blk_mq_devices(table)) { |
4cc96131 MS |
596 | if (!clone_old_rq(rq, md, tio, gfp_mask)) { |
597 | dm_put_live_table(md, srcu_idx); | |
598 | free_old_rq_tio(tio); | |
599 | return NULL; | |
600 | } | |
601 | } | |
602 | dm_put_live_table(md, srcu_idx); | |
603 | ||
604 | return tio; | |
605 | } | |
606 | ||
607 | /* | |
608 | * Called with the queue lock held. | |
609 | */ | |
610 | static int dm_old_prep_fn(struct request_queue *q, struct request *rq) | |
611 | { | |
612 | struct mapped_device *md = q->queuedata; | |
613 | struct dm_rq_target_io *tio; | |
614 | ||
615 | if (unlikely(rq->special)) { | |
616 | DMWARN("Already has something in rq->special."); | |
617 | return BLKPREP_KILL; | |
618 | } | |
619 | ||
620 | tio = dm_old_prep_tio(rq, md, GFP_ATOMIC); | |
621 | if (!tio) | |
622 | return BLKPREP_DEFER; | |
623 | ||
624 | rq->special = tio; | |
625 | rq->cmd_flags |= REQ_DONTPREP; | |
626 | ||
627 | return BLKPREP_OK; | |
628 | } | |
629 | ||
630 | /* | |
631 | * Returns: | |
632 | * 0 : the request has been processed | |
633 | * DM_MAPIO_REQUEUE : the original request needs to be requeued | |
634 | * < 0 : the request was completed due to failure | |
635 | */ | |
636 | static int map_request(struct dm_rq_target_io *tio, struct request *rq, | |
637 | struct mapped_device *md) | |
638 | { | |
639 | int r; | |
640 | struct dm_target *ti = tio->ti; | |
641 | struct request *clone = NULL; | |
642 | ||
643 | if (tio->clone) { | |
644 | clone = tio->clone; | |
645 | r = ti->type->map_rq(ti, clone, &tio->info); | |
646 | } else { | |
647 | r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone); | |
648 | if (r < 0) { | |
649 | /* The target wants to complete the I/O */ | |
650 | dm_kill_unmapped_request(rq, r); | |
651 | return r; | |
652 | } | |
653 | if (r != DM_MAPIO_REMAPPED) | |
654 | return r; | |
655 | if (setup_clone(clone, rq, tio, GFP_ATOMIC)) { | |
656 | /* -ENOMEM */ | |
657 | ti->type->release_clone_rq(clone); | |
658 | return DM_MAPIO_REQUEUE; | |
659 | } | |
660 | } | |
661 | ||
662 | switch (r) { | |
663 | case DM_MAPIO_SUBMITTED: | |
664 | /* The target has taken the I/O to submit by itself later */ | |
665 | break; | |
666 | case DM_MAPIO_REMAPPED: | |
667 | /* The target has remapped the I/O so dispatch it */ | |
668 | trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)), | |
669 | blk_rq_pos(rq)); | |
670 | dm_dispatch_clone_request(clone, rq); | |
671 | break; | |
672 | case DM_MAPIO_REQUEUE: | |
673 | /* The target wants to requeue the I/O */ | |
674 | dm_requeue_original_request(md, tio->orig); | |
675 | break; | |
676 | default: | |
677 | if (r > 0) { | |
678 | DMWARN("unimplemented target map return value: %d", r); | |
679 | BUG(); | |
680 | } | |
681 | ||
682 | /* The target wants to complete the I/O */ | |
683 | dm_kill_unmapped_request(rq, r); | |
684 | return r; | |
685 | } | |
686 | ||
687 | return 0; | |
688 | } | |
689 | ||
690 | static void dm_start_request(struct mapped_device *md, struct request *orig) | |
691 | { | |
692 | if (!orig->q->mq_ops) | |
693 | blk_start_request(orig); | |
694 | else | |
695 | blk_mq_start_request(orig); | |
696 | atomic_inc(&md->pending[rq_data_dir(orig)]); | |
697 | ||
698 | if (md->seq_rq_merge_deadline_usecs) { | |
699 | md->last_rq_pos = rq_end_sector(orig); | |
700 | md->last_rq_rw = rq_data_dir(orig); | |
701 | md->last_rq_start_time = ktime_get(); | |
702 | } | |
703 | ||
704 | if (unlikely(dm_stats_used(&md->stats))) { | |
705 | struct dm_rq_target_io *tio = tio_from_request(orig); | |
706 | tio->duration_jiffies = jiffies; | |
707 | tio->n_sectors = blk_rq_sectors(orig); | |
708 | dm_stats_account_io(&md->stats, rq_data_dir(orig), | |
709 | blk_rq_pos(orig), tio->n_sectors, false, 0, | |
710 | &tio->stats_aux); | |
711 | } | |
712 | ||
713 | /* | |
714 | * Hold the md reference here for the in-flight I/O. | |
715 | * We can't rely on the reference count by device opener, | |
716 | * because the device may be closed during the request completion | |
717 | * when all bios are completed. | |
718 | * See the comment in rq_completed() too. | |
719 | */ | |
720 | dm_get(md); | |
721 | } | |
722 | ||
723 | static void map_tio_request(struct kthread_work *work) | |
724 | { | |
725 | struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work); | |
726 | struct request *rq = tio->orig; | |
727 | struct mapped_device *md = tio->md; | |
728 | ||
729 | if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) | |
730 | dm_requeue_original_request(md, rq); | |
731 | } | |
732 | ||
733 | ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf) | |
734 | { | |
735 | return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs); | |
736 | } | |
737 | ||
738 | #define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000 | |
739 | ||
740 | ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md, | |
741 | const char *buf, size_t count) | |
742 | { | |
743 | unsigned deadline; | |
744 | ||
e83068a5 | 745 | if (dm_get_md_type(md) != DM_TYPE_REQUEST_BASED) |
4cc96131 MS |
746 | return count; |
747 | ||
748 | if (kstrtouint(buf, 10, &deadline)) | |
749 | return -EINVAL; | |
750 | ||
751 | if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS) | |
752 | deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS; | |
753 | ||
754 | md->seq_rq_merge_deadline_usecs = deadline; | |
755 | ||
756 | return count; | |
757 | } | |
758 | ||
759 | static bool dm_old_request_peeked_before_merge_deadline(struct mapped_device *md) | |
760 | { | |
761 | ktime_t kt_deadline; | |
762 | ||
763 | if (!md->seq_rq_merge_deadline_usecs) | |
764 | return false; | |
765 | ||
766 | kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC); | |
767 | kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline); | |
768 | ||
769 | return !ktime_after(ktime_get(), kt_deadline); | |
770 | } | |
771 | ||
772 | /* | |
773 | * q->request_fn for old request-based dm. | |
774 | * Called with the queue lock held. | |
775 | */ | |
776 | static void dm_old_request_fn(struct request_queue *q) | |
777 | { | |
778 | struct mapped_device *md = q->queuedata; | |
779 | struct dm_target *ti = md->immutable_target; | |
780 | struct request *rq; | |
781 | struct dm_rq_target_io *tio; | |
782 | sector_t pos = 0; | |
783 | ||
784 | if (unlikely(!ti)) { | |
785 | int srcu_idx; | |
786 | struct dm_table *map = dm_get_live_table(md, &srcu_idx); | |
787 | ||
788 | ti = dm_table_find_target(map, pos); | |
789 | dm_put_live_table(md, srcu_idx); | |
790 | } | |
791 | ||
792 | /* | |
793 | * For suspend, check blk_queue_stopped() and increment | |
794 | * ->pending within a single queue_lock not to increment the | |
795 | * number of in-flight I/Os after the queue is stopped in | |
796 | * dm_suspend(). | |
797 | */ | |
798 | while (!blk_queue_stopped(q)) { | |
799 | rq = blk_peek_request(q); | |
800 | if (!rq) | |
801 | return; | |
802 | ||
803 | /* always use block 0 to find the target for flushes for now */ | |
804 | pos = 0; | |
805 | if (req_op(rq) != REQ_OP_FLUSH) | |
806 | pos = blk_rq_pos(rq); | |
807 | ||
808 | if ((dm_old_request_peeked_before_merge_deadline(md) && | |
809 | md_in_flight(md) && rq->bio && rq->bio->bi_vcnt == 1 && | |
810 | md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) || | |
811 | (ti->type->busy && ti->type->busy(ti))) { | |
bd9f55ea | 812 | blk_delay_queue(q, 10); |
4cc96131 MS |
813 | return; |
814 | } | |
815 | ||
816 | dm_start_request(md, rq); | |
817 | ||
818 | tio = tio_from_request(rq); | |
819 | /* Establish tio->ti before queuing work (map_tio_request) */ | |
820 | tio->ti = ti; | |
821 | queue_kthread_work(&md->kworker, &tio->work); | |
822 | BUG_ON(!irqs_disabled()); | |
823 | } | |
824 | } | |
825 | ||
826 | /* | |
827 | * Fully initialize a .request_fn request-based queue. | |
828 | */ | |
829 | int dm_old_init_request_queue(struct mapped_device *md) | |
830 | { | |
831 | /* Fully initialize the queue */ | |
832 | if (!blk_init_allocated_queue(md->queue, dm_old_request_fn, NULL)) | |
833 | return -EINVAL; | |
834 | ||
835 | /* disable dm_old_request_fn's merge heuristic by default */ | |
836 | md->seq_rq_merge_deadline_usecs = 0; | |
837 | ||
838 | dm_init_normal_md_queue(md); | |
839 | blk_queue_softirq_done(md->queue, dm_softirq_done); | |
840 | blk_queue_prep_rq(md->queue, dm_old_prep_fn); | |
841 | ||
842 | /* Initialize the request-based DM worker thread */ | |
843 | init_kthread_worker(&md->kworker); | |
844 | md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker, | |
845 | "kdmwork-%s", dm_device_name(md)); | |
7193a9de MS |
846 | if (IS_ERR(md->kworker_task)) |
847 | return PTR_ERR(md->kworker_task); | |
4cc96131 MS |
848 | |
849 | elv_register_queue(md->queue); | |
850 | ||
851 | return 0; | |
852 | } | |
853 | ||
854 | static int dm_mq_init_request(void *data, struct request *rq, | |
855 | unsigned int hctx_idx, unsigned int request_idx, | |
856 | unsigned int numa_node) | |
857 | { | |
858 | struct mapped_device *md = data; | |
859 | struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); | |
860 | ||
861 | /* | |
862 | * Must initialize md member of tio, otherwise it won't | |
863 | * be available in dm_mq_queue_rq. | |
864 | */ | |
865 | tio->md = md; | |
866 | ||
867 | if (md->init_tio_pdu) { | |
868 | /* target-specific per-io data is immediately after the tio */ | |
869 | tio->info.ptr = tio + 1; | |
870 | } | |
871 | ||
872 | return 0; | |
873 | } | |
874 | ||
875 | static int dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, | |
876 | const struct blk_mq_queue_data *bd) | |
877 | { | |
878 | struct request *rq = bd->rq; | |
879 | struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); | |
880 | struct mapped_device *md = tio->md; | |
881 | struct dm_target *ti = md->immutable_target; | |
882 | ||
883 | if (unlikely(!ti)) { | |
884 | int srcu_idx; | |
885 | struct dm_table *map = dm_get_live_table(md, &srcu_idx); | |
886 | ||
887 | ti = dm_table_find_target(map, 0); | |
888 | dm_put_live_table(md, srcu_idx); | |
889 | } | |
890 | ||
7d9595d8 MS |
891 | /* |
892 | * On suspend dm_stop_queue() handles stopping the blk-mq | |
893 | * request_queue BUT: even though the hw_queues are marked | |
894 | * BLK_MQ_S_STOPPED at that point there is still a race that | |
895 | * is allowing block/blk-mq.c to call ->queue_rq against a | |
896 | * hctx that it really shouldn't. The following check guards | |
897 | * against this rarity (albeit _not_ race-free). | |
898 | */ | |
899 | if (unlikely(test_bit(BLK_MQ_S_STOPPED, &hctx->state))) | |
900 | return BLK_MQ_RQ_QUEUE_BUSY; | |
901 | ||
4cc96131 MS |
902 | if (ti->type->busy && ti->type->busy(ti)) |
903 | return BLK_MQ_RQ_QUEUE_BUSY; | |
904 | ||
905 | dm_start_request(md, rq); | |
906 | ||
907 | /* Init tio using md established in .init_request */ | |
908 | init_tio(tio, rq, md); | |
909 | ||
910 | /* | |
911 | * Establish tio->ti before calling map_request(). | |
912 | */ | |
913 | tio->ti = ti; | |
914 | ||
915 | /* Direct call is fine since .queue_rq allows allocations */ | |
916 | if (map_request(tio, rq, md) == DM_MAPIO_REQUEUE) { | |
917 | /* Undo dm_start_request() before requeuing */ | |
918 | rq_end_stats(md, rq); | |
919 | rq_completed(md, rq_data_dir(rq), false); | |
920 | return BLK_MQ_RQ_QUEUE_BUSY; | |
921 | } | |
922 | ||
923 | return BLK_MQ_RQ_QUEUE_OK; | |
924 | } | |
925 | ||
926 | static struct blk_mq_ops dm_mq_ops = { | |
927 | .queue_rq = dm_mq_queue_rq, | |
928 | .map_queue = blk_mq_map_queue, | |
929 | .complete = dm_softirq_done, | |
930 | .init_request = dm_mq_init_request, | |
931 | }; | |
932 | ||
e83068a5 | 933 | int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) |
4cc96131 MS |
934 | { |
935 | struct request_queue *q; | |
e83068a5 | 936 | struct dm_target *immutable_tgt; |
4cc96131 MS |
937 | int err; |
938 | ||
e83068a5 | 939 | if (!dm_table_all_blk_mq_devices(t)) { |
4cc96131 MS |
940 | DMERR("request-based dm-mq may only be stacked on blk-mq device(s)"); |
941 | return -EINVAL; | |
942 | } | |
943 | ||
944 | md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id); | |
945 | if (!md->tag_set) | |
946 | return -ENOMEM; | |
947 | ||
948 | md->tag_set->ops = &dm_mq_ops; | |
949 | md->tag_set->queue_depth = dm_get_blk_mq_queue_depth(); | |
950 | md->tag_set->numa_node = md->numa_node_id; | |
951 | md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE; | |
952 | md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues(); | |
953 | md->tag_set->driver_data = md; | |
954 | ||
955 | md->tag_set->cmd_size = sizeof(struct dm_rq_target_io); | |
e83068a5 | 956 | immutable_tgt = dm_table_get_immutable_target(t); |
4cc96131 MS |
957 | if (immutable_tgt && immutable_tgt->per_io_data_size) { |
958 | /* any target-specific per-io data is immediately after the tio */ | |
959 | md->tag_set->cmd_size += immutable_tgt->per_io_data_size; | |
960 | md->init_tio_pdu = true; | |
961 | } | |
962 | ||
963 | err = blk_mq_alloc_tag_set(md->tag_set); | |
964 | if (err) | |
965 | goto out_kfree_tag_set; | |
966 | ||
967 | q = blk_mq_init_allocated_queue(md->tag_set, md->queue); | |
968 | if (IS_ERR(q)) { | |
969 | err = PTR_ERR(q); | |
970 | goto out_tag_set; | |
971 | } | |
972 | dm_init_md_queue(md); | |
973 | ||
974 | /* backfill 'mq' sysfs registration normally done in blk_register_queue */ | |
975 | blk_mq_register_disk(md->disk); | |
976 | ||
977 | return 0; | |
978 | ||
979 | out_tag_set: | |
980 | blk_mq_free_tag_set(md->tag_set); | |
981 | out_kfree_tag_set: | |
982 | kfree(md->tag_set); | |
983 | ||
984 | return err; | |
985 | } | |
986 | ||
987 | void dm_mq_cleanup_mapped_device(struct mapped_device *md) | |
988 | { | |
989 | if (md->tag_set) { | |
990 | blk_mq_free_tag_set(md->tag_set); | |
991 | kfree(md->tag_set); | |
992 | } | |
993 | } | |
994 | ||
995 | module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR); | |
996 | MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools"); | |
997 | ||
998 | module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR); | |
999 | MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices"); | |
1000 | ||
1001 | module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR); | |
1002 | MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices"); | |
1003 | ||
1004 | module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR); | |
1005 | MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices"); |