Line data Source code
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 : /*
16 : * One of these is allocated per request.
17 : */
18 : struct dm_rq_target_io {
19 : struct mapped_device *md;
20 : struct dm_target *ti;
21 : struct request *orig, *clone;
22 : struct kthread_work work;
23 : blk_status_t error;
24 : union map_info info;
25 : struct dm_stats_aux stats_aux;
26 : unsigned long duration_jiffies;
27 : unsigned n_sectors;
28 : unsigned completed;
29 : };
30 :
31 : #define DM_MQ_NR_HW_QUEUES 1
32 : #define DM_MQ_QUEUE_DEPTH 2048
33 : static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
34 : static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
35 :
36 : /*
37 : * Request-based DM's mempools' reserved IOs set by the user.
38 : */
39 : #define RESERVED_REQUEST_BASED_IOS 256
40 : static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
41 :
42 0 : unsigned dm_get_reserved_rq_based_ios(void)
43 : {
44 0 : return __dm_get_module_param(&reserved_rq_based_ios,
45 : RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS);
46 : }
47 : EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
48 :
49 0 : static unsigned dm_get_blk_mq_nr_hw_queues(void)
50 : {
51 0 : return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);
52 : }
53 :
54 0 : static unsigned dm_get_blk_mq_queue_depth(void)
55 : {
56 0 : return __dm_get_module_param(&dm_mq_queue_depth,
57 : DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);
58 : }
59 :
60 0 : int dm_request_based(struct mapped_device *md)
61 : {
62 0 : return queue_is_mq(md->queue);
63 : }
64 :
65 0 : void dm_start_queue(struct request_queue *q)
66 : {
67 0 : blk_mq_unquiesce_queue(q);
68 0 : blk_mq_kick_requeue_list(q);
69 0 : }
70 :
71 0 : void dm_stop_queue(struct request_queue *q)
72 : {
73 0 : blk_mq_quiesce_queue(q);
74 0 : }
75 :
76 : /*
77 : * Partial completion handling for request-based dm
78 : */
79 0 : static void end_clone_bio(struct bio *clone)
80 : {
81 0 : struct dm_rq_clone_bio_info *info =
82 0 : container_of(clone, struct dm_rq_clone_bio_info, clone);
83 0 : struct dm_rq_target_io *tio = info->tio;
84 0 : unsigned int nr_bytes = info->orig->bi_iter.bi_size;
85 0 : blk_status_t error = clone->bi_status;
86 0 : bool is_last = !clone->bi_next;
87 :
88 0 : bio_put(clone);
89 :
90 0 : if (tio->error)
91 : /*
92 : * An error has already been detected on the request.
93 : * Once error occurred, just let clone->end_io() handle
94 : * the remainder.
95 : */
96 : return;
97 0 : else if (error) {
98 : /*
99 : * Don't notice the error to the upper layer yet.
100 : * The error handling decision is made by the target driver,
101 : * when the request is completed.
102 : */
103 0 : tio->error = error;
104 0 : goto exit;
105 : }
106 :
107 : /*
108 : * I/O for the bio successfully completed.
109 : * Notice the data completion to the upper layer.
110 : */
111 0 : tio->completed += nr_bytes;
112 :
113 : /*
114 : * Update the original request.
115 : * Do not use blk_mq_end_request() here, because it may complete
116 : * the original request before the clone, and break the ordering.
117 : */
118 0 : if (is_last)
119 0 : exit:
120 0 : blk_update_request(tio->orig, BLK_STS_OK, tio->completed);
121 : }
122 :
123 0 : static struct dm_rq_target_io *tio_from_request(struct request *rq)
124 : {
125 0 : return blk_mq_rq_to_pdu(rq);
126 : }
127 :
128 0 : static void rq_end_stats(struct mapped_device *md, struct request *orig)
129 : {
130 0 : if (unlikely(dm_stats_used(&md->stats))) {
131 0 : struct dm_rq_target_io *tio = tio_from_request(orig);
132 0 : tio->duration_jiffies = jiffies - tio->duration_jiffies;
133 0 : dm_stats_account_io(&md->stats, rq_data_dir(orig),
134 : blk_rq_pos(orig), tio->n_sectors, true,
135 : tio->duration_jiffies, &tio->stats_aux);
136 : }
137 0 : }
138 :
139 : /*
140 : * Don't touch any member of the md after calling this function because
141 : * the md may be freed in dm_put() at the end of this function.
142 : * Or do dm_get() before calling this function and dm_put() later.
143 : */
144 0 : static void rq_completed(struct mapped_device *md)
145 : {
146 : /*
147 : * dm_put() must be at the end of this function. See the comment above
148 : */
149 0 : dm_put(md);
150 : }
151 :
152 : /*
153 : * Complete the clone and the original request.
154 : * Must be called without clone's queue lock held,
155 : * see end_clone_request() for more details.
156 : */
157 0 : static void dm_end_request(struct request *clone, blk_status_t error)
158 : {
159 0 : struct dm_rq_target_io *tio = clone->end_io_data;
160 0 : struct mapped_device *md = tio->md;
161 0 : struct request *rq = tio->orig;
162 :
163 0 : blk_rq_unprep_clone(clone);
164 0 : tio->ti->type->release_clone_rq(clone, NULL);
165 :
166 0 : rq_end_stats(md, rq);
167 0 : blk_mq_end_request(rq, error);
168 0 : rq_completed(md);
169 0 : }
170 :
171 0 : static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs)
172 : {
173 0 : blk_mq_delay_kick_requeue_list(q, msecs);
174 : }
175 :
176 0 : void dm_mq_kick_requeue_list(struct mapped_device *md)
177 : {
178 0 : __dm_mq_kick_requeue_list(md->queue, 0);
179 0 : }
180 : EXPORT_SYMBOL(dm_mq_kick_requeue_list);
181 :
182 0 : static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)
183 : {
184 0 : blk_mq_requeue_request(rq, false);
185 0 : __dm_mq_kick_requeue_list(rq->q, msecs);
186 0 : }
187 :
188 0 : static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue)
189 : {
190 0 : struct mapped_device *md = tio->md;
191 0 : struct request *rq = tio->orig;
192 0 : unsigned long delay_ms = delay_requeue ? 100 : 0;
193 :
194 0 : rq_end_stats(md, rq);
195 0 : if (tio->clone) {
196 0 : blk_rq_unprep_clone(tio->clone);
197 0 : tio->ti->type->release_clone_rq(tio->clone, NULL);
198 : }
199 :
200 0 : dm_mq_delay_requeue_request(rq, delay_ms);
201 0 : rq_completed(md);
202 0 : }
203 :
204 0 : static void dm_done(struct request *clone, blk_status_t error, bool mapped)
205 : {
206 0 : int r = DM_ENDIO_DONE;
207 0 : struct dm_rq_target_io *tio = clone->end_io_data;
208 0 : dm_request_endio_fn rq_end_io = NULL;
209 :
210 0 : if (tio->ti) {
211 0 : rq_end_io = tio->ti->type->rq_end_io;
212 :
213 0 : if (mapped && rq_end_io)
214 0 : r = rq_end_io(tio->ti, clone, error, &tio->info);
215 : }
216 :
217 0 : if (unlikely(error == BLK_STS_TARGET)) {
218 0 : if (req_op(clone) == REQ_OP_DISCARD &&
219 0 : !clone->q->limits.max_discard_sectors)
220 0 : disable_discard(tio->md);
221 0 : else if (req_op(clone) == REQ_OP_WRITE_SAME &&
222 0 : !clone->q->limits.max_write_same_sectors)
223 0 : disable_write_same(tio->md);
224 0 : else if (req_op(clone) == REQ_OP_WRITE_ZEROES &&
225 0 : !clone->q->limits.max_write_zeroes_sectors)
226 0 : disable_write_zeroes(tio->md);
227 : }
228 :
229 0 : switch (r) {
230 0 : case DM_ENDIO_DONE:
231 : /* The target wants to complete the I/O */
232 0 : dm_end_request(clone, error);
233 0 : break;
234 : case DM_ENDIO_INCOMPLETE:
235 : /* The target will handle the I/O */
236 : return;
237 0 : case DM_ENDIO_REQUEUE:
238 : /* The target wants to requeue the I/O */
239 0 : dm_requeue_original_request(tio, false);
240 0 : break;
241 0 : case DM_ENDIO_DELAY_REQUEUE:
242 : /* The target wants to requeue the I/O after a delay */
243 0 : dm_requeue_original_request(tio, true);
244 0 : break;
245 0 : default:
246 0 : DMWARN("unimplemented target endio return value: %d", r);
247 0 : BUG();
248 : }
249 : }
250 :
251 : /*
252 : * Request completion handler for request-based dm
253 : */
254 0 : static void dm_softirq_done(struct request *rq)
255 : {
256 0 : bool mapped = true;
257 0 : struct dm_rq_target_io *tio = tio_from_request(rq);
258 0 : struct request *clone = tio->clone;
259 :
260 0 : if (!clone) {
261 0 : struct mapped_device *md = tio->md;
262 :
263 0 : rq_end_stats(md, rq);
264 0 : blk_mq_end_request(rq, tio->error);
265 0 : rq_completed(md);
266 0 : return;
267 : }
268 :
269 0 : if (rq->rq_flags & RQF_FAILED)
270 0 : mapped = false;
271 :
272 0 : dm_done(clone, tio->error, mapped);
273 : }
274 :
275 : /*
276 : * Complete the clone and the original request with the error status
277 : * through softirq context.
278 : */
279 0 : static void dm_complete_request(struct request *rq, blk_status_t error)
280 : {
281 0 : struct dm_rq_target_io *tio = tio_from_request(rq);
282 :
283 0 : tio->error = error;
284 0 : if (likely(!blk_should_fake_timeout(rq->q)))
285 0 : blk_mq_complete_request(rq);
286 0 : }
287 :
288 : /*
289 : * Complete the not-mapped clone and the original request with the error status
290 : * through softirq context.
291 : * Target's rq_end_io() function isn't called.
292 : * This may be used when the target's clone_and_map_rq() function fails.
293 : */
294 0 : static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
295 : {
296 0 : rq->rq_flags |= RQF_FAILED;
297 0 : dm_complete_request(rq, error);
298 0 : }
299 :
300 0 : static void end_clone_request(struct request *clone, blk_status_t error)
301 : {
302 0 : struct dm_rq_target_io *tio = clone->end_io_data;
303 :
304 0 : dm_complete_request(tio->orig, error);
305 0 : }
306 :
307 0 : static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq)
308 : {
309 0 : blk_status_t r;
310 :
311 0 : if (blk_queue_io_stat(clone->q))
312 0 : clone->rq_flags |= RQF_IO_STAT;
313 :
314 0 : clone->start_time_ns = ktime_get_ns();
315 0 : r = blk_insert_cloned_request(clone->q, clone);
316 0 : if (r != BLK_STS_OK && r != BLK_STS_RESOURCE && r != BLK_STS_DEV_RESOURCE)
317 : /* must complete clone in terms of original request */
318 0 : dm_complete_request(rq, r);
319 0 : return r;
320 : }
321 :
322 0 : static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
323 : void *data)
324 : {
325 0 : struct dm_rq_target_io *tio = data;
326 0 : struct dm_rq_clone_bio_info *info =
327 0 : container_of(bio, struct dm_rq_clone_bio_info, clone);
328 :
329 0 : info->orig = bio_orig;
330 0 : info->tio = tio;
331 0 : bio->bi_end_io = end_clone_bio;
332 :
333 0 : return 0;
334 : }
335 :
336 0 : static int setup_clone(struct request *clone, struct request *rq,
337 : struct dm_rq_target_io *tio, gfp_t gfp_mask)
338 : {
339 0 : int r;
340 :
341 0 : r = blk_rq_prep_clone(clone, rq, &tio->md->bs, gfp_mask,
342 : dm_rq_bio_constructor, tio);
343 0 : if (r)
344 : return r;
345 :
346 0 : clone->end_io = end_clone_request;
347 0 : clone->end_io_data = tio;
348 :
349 0 : tio->clone = clone;
350 :
351 0 : return 0;
352 : }
353 :
354 0 : static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
355 : struct mapped_device *md)
356 : {
357 0 : tio->md = md;
358 0 : tio->ti = NULL;
359 0 : tio->clone = NULL;
360 0 : tio->orig = rq;
361 0 : tio->error = 0;
362 0 : tio->completed = 0;
363 : /*
364 : * Avoid initializing info for blk-mq; it passes
365 : * target-specific data through info.ptr
366 : * (see: dm_mq_init_request)
367 : */
368 0 : if (!md->init_tio_pdu)
369 0 : memset(&tio->info, 0, sizeof(tio->info));
370 0 : }
371 :
372 : /*
373 : * Returns:
374 : * DM_MAPIO_* : the request has been processed as indicated
375 : * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued
376 : * < 0 : the request was completed due to failure
377 : */
378 0 : static int map_request(struct dm_rq_target_io *tio)
379 : {
380 0 : int r;
381 0 : struct dm_target *ti = tio->ti;
382 0 : struct mapped_device *md = tio->md;
383 0 : struct request *rq = tio->orig;
384 0 : struct request *clone = NULL;
385 0 : blk_status_t ret;
386 :
387 0 : r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
388 0 : switch (r) {
389 : case DM_MAPIO_SUBMITTED:
390 : /* The target has taken the I/O to submit by itself later */
391 : break;
392 0 : case DM_MAPIO_REMAPPED:
393 0 : if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
394 : /* -ENOMEM */
395 0 : ti->type->release_clone_rq(clone, &tio->info);
396 0 : return DM_MAPIO_REQUEUE;
397 : }
398 :
399 : /* The target has remapped the I/O so dispatch it */
400 0 : trace_block_rq_remap(clone, disk_devt(dm_disk(md)),
401 : blk_rq_pos(rq));
402 0 : ret = dm_dispatch_clone_request(clone, rq);
403 0 : if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) {
404 0 : blk_rq_unprep_clone(clone);
405 0 : blk_mq_cleanup_rq(clone);
406 0 : tio->ti->type->release_clone_rq(clone, &tio->info);
407 0 : tio->clone = NULL;
408 0 : return DM_MAPIO_REQUEUE;
409 : }
410 : break;
411 : case DM_MAPIO_REQUEUE:
412 : /* The target wants to requeue the I/O */
413 : break;
414 0 : case DM_MAPIO_DELAY_REQUEUE:
415 : /* The target wants to requeue the I/O after a delay */
416 0 : dm_requeue_original_request(tio, true);
417 0 : break;
418 : case DM_MAPIO_KILL:
419 : /* The target wants to complete the I/O */
420 0 : dm_kill_unmapped_request(rq, BLK_STS_IOERR);
421 : break;
422 0 : default:
423 0 : DMWARN("unimplemented target map return value: %d", r);
424 0 : BUG();
425 : }
426 :
427 : return r;
428 : }
429 :
430 : /* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */
431 0 : ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
432 : {
433 0 : return sprintf(buf, "%u\n", 0);
434 : }
435 :
436 0 : ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
437 : const char *buf, size_t count)
438 : {
439 0 : return count;
440 : }
441 :
442 0 : static void dm_start_request(struct mapped_device *md, struct request *orig)
443 : {
444 0 : blk_mq_start_request(orig);
445 :
446 0 : if (unlikely(dm_stats_used(&md->stats))) {
447 0 : struct dm_rq_target_io *tio = tio_from_request(orig);
448 0 : tio->duration_jiffies = jiffies;
449 0 : tio->n_sectors = blk_rq_sectors(orig);
450 0 : dm_stats_account_io(&md->stats, rq_data_dir(orig),
451 : blk_rq_pos(orig), tio->n_sectors, false, 0,
452 : &tio->stats_aux);
453 : }
454 :
455 : /*
456 : * Hold the md reference here for the in-flight I/O.
457 : * We can't rely on the reference count by device opener,
458 : * because the device may be closed during the request completion
459 : * when all bios are completed.
460 : * See the comment in rq_completed() too.
461 : */
462 0 : dm_get(md);
463 0 : }
464 :
465 0 : static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
466 : unsigned int hctx_idx, unsigned int numa_node)
467 : {
468 0 : struct mapped_device *md = set->driver_data;
469 0 : struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
470 :
471 : /*
472 : * Must initialize md member of tio, otherwise it won't
473 : * be available in dm_mq_queue_rq.
474 : */
475 0 : tio->md = md;
476 :
477 0 : if (md->init_tio_pdu) {
478 : /* target-specific per-io data is immediately after the tio */
479 0 : tio->info.ptr = tio + 1;
480 : }
481 :
482 0 : return 0;
483 : }
484 :
485 0 : static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
486 : const struct blk_mq_queue_data *bd)
487 : {
488 0 : struct request *rq = bd->rq;
489 0 : struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
490 0 : struct mapped_device *md = tio->md;
491 0 : struct dm_target *ti = md->immutable_target;
492 :
493 0 : if (unlikely(!ti)) {
494 0 : int srcu_idx;
495 0 : struct dm_table *map = dm_get_live_table(md, &srcu_idx);
496 :
497 0 : ti = dm_table_find_target(map, 0);
498 0 : dm_put_live_table(md, srcu_idx);
499 : }
500 :
501 0 : if (ti->type->busy && ti->type->busy(ti))
502 : return BLK_STS_RESOURCE;
503 :
504 0 : dm_start_request(md, rq);
505 :
506 : /* Init tio using md established in .init_request */
507 0 : init_tio(tio, rq, md);
508 :
509 : /*
510 : * Establish tio->ti before calling map_request().
511 : */
512 0 : tio->ti = ti;
513 :
514 : /* Direct call is fine since .queue_rq allows allocations */
515 0 : if (map_request(tio) == DM_MAPIO_REQUEUE) {
516 : /* Undo dm_start_request() before requeuing */
517 0 : rq_end_stats(md, rq);
518 0 : rq_completed(md);
519 0 : return BLK_STS_RESOURCE;
520 : }
521 :
522 : return BLK_STS_OK;
523 : }
524 :
525 : static const struct blk_mq_ops dm_mq_ops = {
526 : .queue_rq = dm_mq_queue_rq,
527 : .complete = dm_softirq_done,
528 : .init_request = dm_mq_init_request,
529 : };
530 :
531 0 : int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
532 : {
533 0 : struct request_queue *q;
534 0 : struct dm_target *immutable_tgt;
535 0 : int err;
536 :
537 0 : md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
538 0 : if (!md->tag_set)
539 : return -ENOMEM;
540 :
541 0 : md->tag_set->ops = &dm_mq_ops;
542 0 : md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
543 0 : md->tag_set->numa_node = md->numa_node_id;
544 0 : md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_STACKING;
545 0 : md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
546 0 : md->tag_set->driver_data = md;
547 :
548 0 : md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
549 0 : immutable_tgt = dm_table_get_immutable_target(t);
550 0 : if (immutable_tgt && immutable_tgt->per_io_data_size) {
551 : /* any target-specific per-io data is immediately after the tio */
552 0 : md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
553 0 : md->init_tio_pdu = true;
554 : }
555 :
556 0 : err = blk_mq_alloc_tag_set(md->tag_set);
557 0 : if (err)
558 0 : goto out_kfree_tag_set;
559 :
560 0 : q = blk_mq_init_allocated_queue(md->tag_set, md->queue, true);
561 0 : if (IS_ERR(q)) {
562 0 : err = PTR_ERR(q);
563 0 : goto out_tag_set;
564 : }
565 :
566 : return 0;
567 :
568 0 : out_tag_set:
569 0 : blk_mq_free_tag_set(md->tag_set);
570 0 : out_kfree_tag_set:
571 0 : kfree(md->tag_set);
572 :
573 0 : return err;
574 : }
575 :
576 0 : void dm_mq_cleanup_mapped_device(struct mapped_device *md)
577 : {
578 0 : if (md->tag_set) {
579 0 : blk_mq_free_tag_set(md->tag_set);
580 0 : kfree(md->tag_set);
581 : }
582 0 : }
583 :
584 : module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
585 : MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
586 :
587 : /* Unused, but preserved for userspace compatibility */
588 : static bool use_blk_mq = true;
589 : module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
590 : MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
591 :
592 : module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR);
593 : MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices");
594 :
595 : module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR);
596 : MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");
|
