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