1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
5 * This file is released under the GPL.
11 #include <linux/blk-mq.h>
13 #define DM_MSG_PREFIX "core-rq"
16 * One of these is allocated per request.
18 struct dm_rq_target_io
{
19 struct mapped_device
*md
;
21 struct request
*orig
, *clone
;
22 struct kthread_work work
;
25 struct dm_stats_aux stats_aux
;
26 unsigned long duration_jiffies
;
27 unsigned int n_sectors
;
28 unsigned int completed
;
31 #define DM_MQ_NR_HW_QUEUES 1
32 #define DM_MQ_QUEUE_DEPTH 2048
33 static unsigned int dm_mq_nr_hw_queues
= DM_MQ_NR_HW_QUEUES
;
34 static unsigned int dm_mq_queue_depth
= DM_MQ_QUEUE_DEPTH
;
37 * Request-based DM's mempools' reserved IOs set by the user.
39 #define RESERVED_REQUEST_BASED_IOS 256
40 static unsigned int reserved_rq_based_ios
= RESERVED_REQUEST_BASED_IOS
;
42 unsigned int dm_get_reserved_rq_based_ios(void)
44 return __dm_get_module_param(&reserved_rq_based_ios
,
45 RESERVED_REQUEST_BASED_IOS
, DM_RESERVED_MAX_IOS
);
48 static unsigned int dm_get_blk_mq_nr_hw_queues(void)
50 return __dm_get_module_param(&dm_mq_nr_hw_queues
, 1, 32);
53 static unsigned int dm_get_blk_mq_queue_depth(void)
55 return __dm_get_module_param(&dm_mq_queue_depth
,
56 DM_MQ_QUEUE_DEPTH
, BLK_MQ_MAX_DEPTH
);
59 int dm_request_based(struct mapped_device
*md
)
61 return queue_is_mq(md
->queue
);
64 void dm_start_queue(struct request_queue
*q
)
66 blk_mq_unquiesce_queue(q
);
67 blk_mq_kick_requeue_list(q
);
70 void dm_stop_queue(struct request_queue
*q
)
72 blk_mq_quiesce_queue(q
);
76 * Partial completion handling for request-based dm
78 static void end_clone_bio(struct bio
*clone
)
80 struct dm_rq_clone_bio_info
*info
=
81 container_of(clone
, struct dm_rq_clone_bio_info
, clone
);
82 struct dm_rq_target_io
*tio
= info
->tio
;
83 unsigned int nr_bytes
= info
->orig
->bi_iter
.bi_size
;
84 blk_status_t error
= clone
->bi_status
;
85 bool is_last
= !clone
->bi_next
;
91 * An error has already been detected on the request.
92 * Once error occurred, just let clone->end_io() handle
98 * Don't notice the error to the upper layer yet.
99 * The error handling decision is made by the target driver,
100 * when the request is completed.
107 * I/O for the bio successfully completed.
108 * Notice the data completion to the upper layer.
110 tio
->completed
+= nr_bytes
;
113 * Update the original request.
114 * Do not use blk_mq_end_request() here, because it may complete
115 * the original request before the clone, and break the ordering.
119 blk_update_request(tio
->orig
, BLK_STS_OK
, tio
->completed
);
122 static struct dm_rq_target_io
*tio_from_request(struct request
*rq
)
124 return blk_mq_rq_to_pdu(rq
);
127 static void rq_end_stats(struct mapped_device
*md
, struct request
*orig
)
129 if (unlikely(dm_stats_used(&md
->stats
))) {
130 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
132 tio
->duration_jiffies
= jiffies
- tio
->duration_jiffies
;
133 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
);
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.
144 static void rq_completed(struct mapped_device
*md
)
147 * dm_put() must be at the end of this function. See the comment above
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.
157 static void dm_end_request(struct request
*clone
, blk_status_t error
)
159 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
160 struct mapped_device
*md
= tio
->md
;
161 struct request
*rq
= tio
->orig
;
163 blk_rq_unprep_clone(clone
);
164 tio
->ti
->type
->release_clone_rq(clone
, NULL
);
166 rq_end_stats(md
, rq
);
167 blk_mq_end_request(rq
, error
);
171 static void __dm_mq_kick_requeue_list(struct request_queue
*q
, unsigned long msecs
)
173 blk_mq_delay_kick_requeue_list(q
, msecs
);
176 void dm_mq_kick_requeue_list(struct mapped_device
*md
)
178 __dm_mq_kick_requeue_list(md
->queue
, 0);
180 EXPORT_SYMBOL(dm_mq_kick_requeue_list
);
182 static void dm_mq_delay_requeue_request(struct request
*rq
, unsigned long msecs
)
184 blk_mq_requeue_request(rq
, false);
185 __dm_mq_kick_requeue_list(rq
->q
, msecs
);
188 static void dm_requeue_original_request(struct dm_rq_target_io
*tio
, bool delay_requeue
)
190 struct mapped_device
*md
= tio
->md
;
191 struct request
*rq
= tio
->orig
;
192 unsigned long delay_ms
= delay_requeue
? 100 : 0;
194 rq_end_stats(md
, rq
);
196 blk_rq_unprep_clone(tio
->clone
);
197 tio
->ti
->type
->release_clone_rq(tio
->clone
, NULL
);
200 dm_mq_delay_requeue_request(rq
, delay_ms
);
204 static void dm_done(struct request
*clone
, blk_status_t error
, bool mapped
)
206 int r
= DM_ENDIO_DONE
;
207 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
208 dm_request_endio_fn rq_end_io
= NULL
;
211 rq_end_io
= tio
->ti
->type
->rq_end_io
;
213 if (mapped
&& rq_end_io
)
214 r
= rq_end_io(tio
->ti
, clone
, error
, &tio
->info
);
217 if (unlikely(error
== BLK_STS_TARGET
)) {
218 if (req_op(clone
) == REQ_OP_DISCARD
&&
219 !clone
->q
->limits
.max_discard_sectors
)
220 disable_discard(tio
->md
);
221 else if (req_op(clone
) == REQ_OP_WRITE_ZEROES
&&
222 !clone
->q
->limits
.max_write_zeroes_sectors
)
223 disable_write_zeroes(tio
->md
);
228 /* The target wants to complete the I/O */
229 dm_end_request(clone
, error
);
231 case DM_ENDIO_INCOMPLETE
:
232 /* The target will handle the I/O */
234 case DM_ENDIO_REQUEUE
:
235 /* The target wants to requeue the I/O */
236 dm_requeue_original_request(tio
, false);
238 case DM_ENDIO_DELAY_REQUEUE
:
239 /* The target wants to requeue the I/O after a delay */
240 dm_requeue_original_request(tio
, true);
243 DMCRIT("unimplemented target endio return value: %d", r
);
249 * Request completion handler for request-based dm
251 static void dm_softirq_done(struct request
*rq
)
254 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
255 struct request
*clone
= tio
->clone
;
258 struct mapped_device
*md
= tio
->md
;
260 rq_end_stats(md
, rq
);
261 blk_mq_end_request(rq
, tio
->error
);
266 if (rq
->rq_flags
& RQF_FAILED
)
269 dm_done(clone
, tio
->error
, mapped
);
273 * Complete the clone and the original request with the error status
274 * through softirq context.
276 static void dm_complete_request(struct request
*rq
, blk_status_t error
)
278 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
281 if (likely(!blk_should_fake_timeout(rq
->q
)))
282 blk_mq_complete_request(rq
);
286 * Complete the not-mapped clone and the original request with the error status
287 * through softirq context.
288 * Target's rq_end_io() function isn't called.
289 * This may be used when the target's clone_and_map_rq() function fails.
291 static void dm_kill_unmapped_request(struct request
*rq
, blk_status_t error
)
293 rq
->rq_flags
|= RQF_FAILED
;
294 dm_complete_request(rq
, error
);
297 static enum rq_end_io_ret
end_clone_request(struct request
*clone
,
300 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
302 dm_complete_request(tio
->orig
, error
);
303 return RQ_END_IO_NONE
;
306 static int dm_rq_bio_constructor(struct bio
*bio
, struct bio
*bio_orig
,
309 struct dm_rq_target_io
*tio
= data
;
310 struct dm_rq_clone_bio_info
*info
=
311 container_of(bio
, struct dm_rq_clone_bio_info
, clone
);
313 info
->orig
= bio_orig
;
315 bio
->bi_end_io
= end_clone_bio
;
320 static int setup_clone(struct request
*clone
, struct request
*rq
,
321 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
325 r
= blk_rq_prep_clone(clone
, rq
, &tio
->md
->mempools
->bs
, gfp_mask
,
326 dm_rq_bio_constructor
, tio
);
330 clone
->end_io
= end_clone_request
;
331 clone
->end_io_data
= tio
;
338 static void init_tio(struct dm_rq_target_io
*tio
, struct request
*rq
,
339 struct mapped_device
*md
)
348 * Avoid initializing info for blk-mq; it passes
349 * target-specific data through info.ptr
350 * (see: dm_mq_init_request)
352 if (!md
->init_tio_pdu
)
353 memset(&tio
->info
, 0, sizeof(tio
->info
));
358 * DM_MAPIO_* : the request has been processed as indicated
359 * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued
360 * < 0 : the request was completed due to failure
362 static int map_request(struct dm_rq_target_io
*tio
)
365 struct dm_target
*ti
= tio
->ti
;
366 struct mapped_device
*md
= tio
->md
;
367 struct request
*rq
= tio
->orig
;
368 struct request
*clone
= NULL
;
371 r
= ti
->type
->clone_and_map_rq(ti
, rq
, &tio
->info
, &clone
);
373 case DM_MAPIO_SUBMITTED
:
374 /* The target has taken the I/O to submit by itself later */
376 case DM_MAPIO_REMAPPED
:
377 if (setup_clone(clone
, rq
, tio
, GFP_ATOMIC
)) {
379 ti
->type
->release_clone_rq(clone
, &tio
->info
);
380 return DM_MAPIO_REQUEUE
;
383 /* The target has remapped the I/O so dispatch it */
384 trace_block_rq_remap(clone
, disk_devt(dm_disk(md
)),
386 ret
= blk_insert_cloned_request(clone
);
390 case BLK_STS_RESOURCE
:
391 case BLK_STS_DEV_RESOURCE
:
392 blk_rq_unprep_clone(clone
);
393 blk_mq_cleanup_rq(clone
);
394 tio
->ti
->type
->release_clone_rq(clone
, &tio
->info
);
396 return DM_MAPIO_REQUEUE
;
398 /* must complete clone in terms of original request */
399 dm_complete_request(rq
, ret
);
402 case DM_MAPIO_REQUEUE
:
403 /* The target wants to requeue the I/O */
405 case DM_MAPIO_DELAY_REQUEUE
:
406 /* The target wants to requeue the I/O after a delay */
407 dm_requeue_original_request(tio
, true);
410 /* The target wants to complete the I/O */
411 dm_kill_unmapped_request(rq
, BLK_STS_IOERR
);
414 DMCRIT("unimplemented target map return value: %d", r
);
421 /* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */
422 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device
*md
, char *buf
)
424 return sprintf(buf
, "%u\n", 0);
427 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device
*md
,
428 const char *buf
, size_t count
)
433 static void dm_start_request(struct mapped_device
*md
, struct request
*orig
)
435 blk_mq_start_request(orig
);
437 if (unlikely(dm_stats_used(&md
->stats
))) {
438 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
440 tio
->duration_jiffies
= jiffies
;
441 tio
->n_sectors
= blk_rq_sectors(orig
);
442 dm_stats_account_io(&md
->stats
, rq_data_dir(orig
),
443 blk_rq_pos(orig
), tio
->n_sectors
, false, 0,
448 * Hold the md reference here for the in-flight I/O.
449 * We can't rely on the reference count by device opener,
450 * because the device may be closed during the request completion
451 * when all bios are completed.
452 * See the comment in rq_completed() too.
457 static int dm_mq_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
458 unsigned int hctx_idx
, unsigned int numa_node
)
460 struct mapped_device
*md
= set
->driver_data
;
461 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
464 * Must initialize md member of tio, otherwise it won't
465 * be available in dm_mq_queue_rq.
469 if (md
->init_tio_pdu
) {
470 /* target-specific per-io data is immediately after the tio */
471 tio
->info
.ptr
= tio
+ 1;
477 static blk_status_t
dm_mq_queue_rq(struct blk_mq_hw_ctx
*hctx
,
478 const struct blk_mq_queue_data
*bd
)
480 struct request
*rq
= bd
->rq
;
481 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
482 struct mapped_device
*md
= tio
->md
;
483 struct dm_target
*ti
= md
->immutable_target
;
486 * blk-mq's unquiesce may come from outside events, such as
487 * elevator switch, updating nr_requests or others, and request may
488 * come during suspend, so simply ask for blk-mq to requeue it.
490 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND
, &md
->flags
)))
491 return BLK_STS_RESOURCE
;
495 struct dm_table
*map
;
497 map
= dm_get_live_table(md
, &srcu_idx
);
498 if (unlikely(!map
)) {
499 DMERR_LIMIT("%s: mapping table unavailable, erroring io",
501 dm_put_live_table(md
, srcu_idx
);
502 return BLK_STS_IOERR
;
504 ti
= dm_table_find_target(map
, 0);
505 dm_put_live_table(md
, srcu_idx
);
508 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
509 return BLK_STS_RESOURCE
;
511 dm_start_request(md
, rq
);
513 /* Init tio using md established in .init_request */
514 init_tio(tio
, rq
, md
);
517 * Establish tio->ti before calling map_request().
521 /* Direct call is fine since .queue_rq allows allocations */
522 if (map_request(tio
) == DM_MAPIO_REQUEUE
) {
523 /* Undo dm_start_request() before requeuing */
524 rq_end_stats(md
, rq
);
526 return BLK_STS_RESOURCE
;
532 static const struct blk_mq_ops dm_mq_ops
= {
533 .queue_rq
= dm_mq_queue_rq
,
534 .complete
= dm_softirq_done
,
535 .init_request
= dm_mq_init_request
,
538 int dm_mq_init_request_queue(struct mapped_device
*md
, struct dm_table
*t
)
540 struct dm_target
*immutable_tgt
;
543 md
->tag_set
= kzalloc_node(sizeof(struct blk_mq_tag_set
), GFP_KERNEL
, md
->numa_node_id
);
547 md
->tag_set
->ops
= &dm_mq_ops
;
548 md
->tag_set
->queue_depth
= dm_get_blk_mq_queue_depth();
549 md
->tag_set
->numa_node
= md
->numa_node_id
;
550 md
->tag_set
->flags
= BLK_MQ_F_SHOULD_MERGE
| BLK_MQ_F_STACKING
;
551 md
->tag_set
->nr_hw_queues
= dm_get_blk_mq_nr_hw_queues();
552 md
->tag_set
->driver_data
= md
;
554 md
->tag_set
->cmd_size
= sizeof(struct dm_rq_target_io
);
555 immutable_tgt
= dm_table_get_immutable_target(t
);
556 if (immutable_tgt
&& immutable_tgt
->per_io_data_size
) {
557 /* any target-specific per-io data is immediately after the tio */
558 md
->tag_set
->cmd_size
+= immutable_tgt
->per_io_data_size
;
559 md
->init_tio_pdu
= true;
562 err
= blk_mq_alloc_tag_set(md
->tag_set
);
564 goto out_kfree_tag_set
;
566 err
= blk_mq_init_allocated_queue(md
->tag_set
, md
->queue
);
572 blk_mq_free_tag_set(md
->tag_set
);
580 void dm_mq_cleanup_mapped_device(struct mapped_device
*md
)
583 blk_mq_free_tag_set(md
->tag_set
);
589 module_param(reserved_rq_based_ios
, uint
, 0644);
590 MODULE_PARM_DESC(reserved_rq_based_ios
, "Reserved IOs in request-based mempools");
592 /* Unused, but preserved for userspace compatibility */
593 static bool use_blk_mq
= true;
594 module_param(use_blk_mq
, bool, 0644);
595 MODULE_PARM_DESC(use_blk_mq
, "Use block multiqueue for request-based DM devices");
597 module_param(dm_mq_nr_hw_queues
, uint
, 0644);
598 MODULE_PARM_DESC(dm_mq_nr_hw_queues
, "Number of hardware queues for request-based dm-mq devices");
600 module_param(dm_mq_queue_depth
, uint
, 0644);
601 MODULE_PARM_DESC(dm_mq_queue_depth
, "Queue depth for request-based dm-mq devices");