2 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
4 * This file is released under the GPL.
10 #include <linux/elevator.h> /* for rq_end_sector() */
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
;
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
;
37 * Request-based DM's mempools' reserved IOs set by the user.
39 #define RESERVED_REQUEST_BASED_IOS 256
40 static unsigned reserved_rq_based_ios
= RESERVED_REQUEST_BASED_IOS
;
42 unsigned 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
);
47 EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios
);
49 static unsigned dm_get_blk_mq_nr_hw_queues(void)
51 return __dm_get_module_param(&dm_mq_nr_hw_queues
, 1, 32);
54 static unsigned dm_get_blk_mq_queue_depth(void)
56 return __dm_get_module_param(&dm_mq_queue_depth
,
57 DM_MQ_QUEUE_DEPTH
, BLK_MQ_MAX_DEPTH
);
60 int dm_request_based(struct mapped_device
*md
)
62 return queue_is_mq(md
->queue
);
65 void dm_start_queue(struct request_queue
*q
)
67 blk_mq_unquiesce_queue(q
);
68 blk_mq_kick_requeue_list(q
);
71 void dm_stop_queue(struct request_queue
*q
)
73 if (blk_mq_queue_stopped(q
))
76 blk_mq_quiesce_queue(q
);
80 * Partial completion handling for request-based dm
82 static void end_clone_bio(struct bio
*clone
)
84 struct dm_rq_clone_bio_info
*info
=
85 container_of(clone
, struct dm_rq_clone_bio_info
, clone
);
86 struct dm_rq_target_io
*tio
= info
->tio
;
87 unsigned int nr_bytes
= info
->orig
->bi_iter
.bi_size
;
88 blk_status_t error
= clone
->bi_status
;
89 bool is_last
= !clone
->bi_next
;
95 * An error has already been detected on the request.
96 * Once error occurred, just let clone->end_io() handle
102 * Don't notice the error to the upper layer yet.
103 * The error handling decision is made by the target driver,
104 * when the request is completed.
111 * I/O for the bio successfully completed.
112 * Notice the data completion to the upper layer.
114 tio
->completed
+= nr_bytes
;
117 * Update the original request.
118 * Do not use blk_end_request() here, because it may complete
119 * the original request before the clone, and break the ordering.
123 blk_update_request(tio
->orig
, BLK_STS_OK
, tio
->completed
);
126 static struct dm_rq_target_io
*tio_from_request(struct request
*rq
)
128 return blk_mq_rq_to_pdu(rq
);
131 static void rq_end_stats(struct mapped_device
*md
, struct request
*orig
)
133 if (unlikely(dm_stats_used(&md
->stats
))) {
134 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
135 tio
->duration_jiffies
= jiffies
- tio
->duration_jiffies
;
136 dm_stats_account_io(&md
->stats
, rq_data_dir(orig
),
137 blk_rq_pos(orig
), tio
->n_sectors
, true,
138 tio
->duration_jiffies
, &tio
->stats_aux
);
143 * Don't touch any member of the md after calling this function because
144 * the md may be freed in dm_put() at the end of this function.
145 * Or do dm_get() before calling this function and dm_put() later.
147 static void rq_completed(struct mapped_device
*md
)
149 /* nudge anyone waiting on suspend queue */
150 if (unlikely(wq_has_sleeper(&md
->wait
)))
154 * dm_put() must be at the end of this function. See the comment above
160 * Complete the clone and the original request.
161 * Must be called without clone's queue lock held,
162 * see end_clone_request() for more details.
164 static void dm_end_request(struct request
*clone
, blk_status_t error
)
166 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
167 struct mapped_device
*md
= tio
->md
;
168 struct request
*rq
= tio
->orig
;
170 blk_rq_unprep_clone(clone
);
171 tio
->ti
->type
->release_clone_rq(clone
);
173 rq_end_stats(md
, rq
);
174 blk_mq_end_request(rq
, error
);
178 static void __dm_mq_kick_requeue_list(struct request_queue
*q
, unsigned long msecs
)
180 blk_mq_delay_kick_requeue_list(q
, msecs
);
183 void dm_mq_kick_requeue_list(struct mapped_device
*md
)
185 __dm_mq_kick_requeue_list(dm_get_md_queue(md
), 0);
187 EXPORT_SYMBOL(dm_mq_kick_requeue_list
);
189 static void dm_mq_delay_requeue_request(struct request
*rq
, unsigned long msecs
)
191 blk_mq_requeue_request(rq
, false);
192 __dm_mq_kick_requeue_list(rq
->q
, msecs
);
195 static void dm_requeue_original_request(struct dm_rq_target_io
*tio
, bool delay_requeue
)
197 struct mapped_device
*md
= tio
->md
;
198 struct request
*rq
= tio
->orig
;
199 unsigned long delay_ms
= delay_requeue
? 100 : 0;
201 rq_end_stats(md
, rq
);
203 blk_rq_unprep_clone(tio
->clone
);
204 tio
->ti
->type
->release_clone_rq(tio
->clone
);
207 dm_mq_delay_requeue_request(rq
, delay_ms
);
211 static void dm_done(struct request
*clone
, blk_status_t error
, bool mapped
)
213 int r
= DM_ENDIO_DONE
;
214 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
215 dm_request_endio_fn rq_end_io
= NULL
;
218 rq_end_io
= tio
->ti
->type
->rq_end_io
;
220 if (mapped
&& rq_end_io
)
221 r
= rq_end_io(tio
->ti
, clone
, error
, &tio
->info
);
224 if (unlikely(error
== BLK_STS_TARGET
)) {
225 if (req_op(clone
) == REQ_OP_WRITE_SAME
&&
226 !clone
->q
->limits
.max_write_same_sectors
)
227 disable_write_same(tio
->md
);
228 if (req_op(clone
) == REQ_OP_WRITE_ZEROES
&&
229 !clone
->q
->limits
.max_write_zeroes_sectors
)
230 disable_write_zeroes(tio
->md
);
235 /* The target wants to complete the I/O */
236 dm_end_request(clone
, error
);
238 case DM_ENDIO_INCOMPLETE
:
239 /* The target will handle the I/O */
241 case DM_ENDIO_REQUEUE
:
242 /* The target wants to requeue the I/O */
243 dm_requeue_original_request(tio
, false);
245 case DM_ENDIO_DELAY_REQUEUE
:
246 /* The target wants to requeue the I/O after a delay */
247 dm_requeue_original_request(tio
, true);
250 DMWARN("unimplemented target endio return value: %d", r
);
256 * Request completion handler for request-based dm
258 static void dm_softirq_done(struct request
*rq
)
261 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
262 struct request
*clone
= tio
->clone
;
265 struct mapped_device
*md
= tio
->md
;
267 rq_end_stats(md
, rq
);
268 blk_mq_end_request(rq
, tio
->error
);
273 if (rq
->rq_flags
& RQF_FAILED
)
276 dm_done(clone
, tio
->error
, mapped
);
280 * Complete the clone and the original request with the error status
281 * through softirq context.
283 static void dm_complete_request(struct request
*rq
, blk_status_t error
)
285 struct dm_rq_target_io
*tio
= tio_from_request(rq
);
288 blk_mq_complete_request(rq
);
292 * Complete the not-mapped clone and the original request with the error status
293 * through softirq context.
294 * Target's rq_end_io() function isn't called.
295 * This may be used when the target's clone_and_map_rq() function fails.
297 static void dm_kill_unmapped_request(struct request
*rq
, blk_status_t error
)
299 rq
->rq_flags
|= RQF_FAILED
;
300 dm_complete_request(rq
, error
);
303 static void end_clone_request(struct request
*clone
, blk_status_t error
)
305 struct dm_rq_target_io
*tio
= clone
->end_io_data
;
307 dm_complete_request(tio
->orig
, error
);
310 static blk_status_t
dm_dispatch_clone_request(struct request
*clone
, struct request
*rq
)
314 if (blk_queue_io_stat(clone
->q
))
315 clone
->rq_flags
|= RQF_IO_STAT
;
317 clone
->start_time_ns
= ktime_get_ns();
318 r
= blk_insert_cloned_request(clone
->q
, clone
);
319 if (r
!= BLK_STS_OK
&& r
!= BLK_STS_RESOURCE
&& r
!= BLK_STS_DEV_RESOURCE
)
320 /* must complete clone in terms of original request */
321 dm_complete_request(rq
, r
);
325 static int dm_rq_bio_constructor(struct bio
*bio
, struct bio
*bio_orig
,
328 struct dm_rq_target_io
*tio
= data
;
329 struct dm_rq_clone_bio_info
*info
=
330 container_of(bio
, struct dm_rq_clone_bio_info
, clone
);
332 info
->orig
= bio_orig
;
334 bio
->bi_end_io
= end_clone_bio
;
339 static int setup_clone(struct request
*clone
, struct request
*rq
,
340 struct dm_rq_target_io
*tio
, gfp_t gfp_mask
)
344 r
= blk_rq_prep_clone(clone
, rq
, &tio
->md
->bs
, gfp_mask
,
345 dm_rq_bio_constructor
, tio
);
349 clone
->end_io
= end_clone_request
;
350 clone
->end_io_data
= tio
;
357 static void init_tio(struct dm_rq_target_io
*tio
, struct request
*rq
,
358 struct mapped_device
*md
)
367 * Avoid initializing info for blk-mq; it passes
368 * target-specific data through info.ptr
369 * (see: dm_mq_init_request)
371 if (!md
->init_tio_pdu
)
372 memset(&tio
->info
, 0, sizeof(tio
->info
));
377 * DM_MAPIO_* : the request has been processed as indicated
378 * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued
379 * < 0 : the request was completed due to failure
381 static int map_request(struct dm_rq_target_io
*tio
)
384 struct dm_target
*ti
= tio
->ti
;
385 struct mapped_device
*md
= tio
->md
;
386 struct request
*rq
= tio
->orig
;
387 struct request
*clone
= NULL
;
390 r
= ti
->type
->clone_and_map_rq(ti
, rq
, &tio
->info
, &clone
);
392 case DM_MAPIO_SUBMITTED
:
393 /* The target has taken the I/O to submit by itself later */
395 case DM_MAPIO_REMAPPED
:
396 if (setup_clone(clone
, rq
, tio
, GFP_ATOMIC
)) {
398 ti
->type
->release_clone_rq(clone
);
399 return DM_MAPIO_REQUEUE
;
402 /* The target has remapped the I/O so dispatch it */
403 trace_block_rq_remap(clone
->q
, clone
, disk_devt(dm_disk(md
)),
405 ret
= dm_dispatch_clone_request(clone
, rq
);
406 if (ret
== BLK_STS_RESOURCE
|| ret
== BLK_STS_DEV_RESOURCE
) {
407 blk_rq_unprep_clone(clone
);
408 tio
->ti
->type
->release_clone_rq(clone
);
410 return DM_MAPIO_REQUEUE
;
413 case DM_MAPIO_REQUEUE
:
414 /* The target wants to requeue the I/O */
416 case DM_MAPIO_DELAY_REQUEUE
:
417 /* The target wants to requeue the I/O after a delay */
418 dm_requeue_original_request(tio
, true);
421 /* The target wants to complete the I/O */
422 dm_kill_unmapped_request(rq
, BLK_STS_IOERR
);
425 DMWARN("unimplemented target map return value: %d", r
);
432 /* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */
433 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device
*md
, char *buf
)
435 return sprintf(buf
, "%u\n", 0);
438 ssize_t
dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device
*md
,
439 const char *buf
, size_t count
)
444 static void dm_start_request(struct mapped_device
*md
, struct request
*orig
)
446 blk_mq_start_request(orig
);
448 if (unlikely(dm_stats_used(&md
->stats
))) {
449 struct dm_rq_target_io
*tio
= tio_from_request(orig
);
450 tio
->duration_jiffies
= jiffies
;
451 tio
->n_sectors
= blk_rq_sectors(orig
);
452 dm_stats_account_io(&md
->stats
, rq_data_dir(orig
),
453 blk_rq_pos(orig
), tio
->n_sectors
, false, 0,
458 * Hold the md reference here for the in-flight I/O.
459 * We can't rely on the reference count by device opener,
460 * because the device may be closed during the request completion
461 * when all bios are completed.
462 * See the comment in rq_completed() too.
467 static int dm_mq_init_request(struct blk_mq_tag_set
*set
, struct request
*rq
,
468 unsigned int hctx_idx
, unsigned int numa_node
)
470 struct mapped_device
*md
= set
->driver_data
;
471 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
474 * Must initialize md member of tio, otherwise it won't
475 * be available in dm_mq_queue_rq.
479 if (md
->init_tio_pdu
) {
480 /* target-specific per-io data is immediately after the tio */
481 tio
->info
.ptr
= tio
+ 1;
487 static blk_status_t
dm_mq_queue_rq(struct blk_mq_hw_ctx
*hctx
,
488 const struct blk_mq_queue_data
*bd
)
490 struct request
*rq
= bd
->rq
;
491 struct dm_rq_target_io
*tio
= blk_mq_rq_to_pdu(rq
);
492 struct mapped_device
*md
= tio
->md
;
493 struct dm_target
*ti
= md
->immutable_target
;
497 struct dm_table
*map
= dm_get_live_table(md
, &srcu_idx
);
499 ti
= dm_table_find_target(map
, 0);
500 dm_put_live_table(md
, srcu_idx
);
503 if (ti
->type
->busy
&& ti
->type
->busy(ti
))
504 return BLK_STS_RESOURCE
;
506 dm_start_request(md
, rq
);
508 /* Init tio using md established in .init_request */
509 init_tio(tio
, rq
, md
);
512 * Establish tio->ti before calling map_request().
516 /* Direct call is fine since .queue_rq allows allocations */
517 if (map_request(tio
) == DM_MAPIO_REQUEUE
) {
518 /* Undo dm_start_request() before requeuing */
519 rq_end_stats(md
, rq
);
521 return BLK_STS_RESOURCE
;
527 static const struct blk_mq_ops dm_mq_ops
= {
528 .queue_rq
= dm_mq_queue_rq
,
529 .complete
= dm_softirq_done
,
530 .init_request
= dm_mq_init_request
,
533 int dm_mq_init_request_queue(struct mapped_device
*md
, struct dm_table
*t
)
535 struct request_queue
*q
;
536 struct dm_target
*immutable_tgt
;
539 md
->tag_set
= kzalloc_node(sizeof(struct blk_mq_tag_set
), GFP_KERNEL
, md
->numa_node_id
);
543 md
->tag_set
->ops
= &dm_mq_ops
;
544 md
->tag_set
->queue_depth
= dm_get_blk_mq_queue_depth();
545 md
->tag_set
->numa_node
= md
->numa_node_id
;
546 md
->tag_set
->flags
= BLK_MQ_F_SHOULD_MERGE
;
547 md
->tag_set
->nr_hw_queues
= dm_get_blk_mq_nr_hw_queues();
548 md
->tag_set
->driver_data
= md
;
550 md
->tag_set
->cmd_size
= sizeof(struct dm_rq_target_io
);
551 immutable_tgt
= dm_table_get_immutable_target(t
);
552 if (immutable_tgt
&& immutable_tgt
->per_io_data_size
) {
553 /* any target-specific per-io data is immediately after the tio */
554 md
->tag_set
->cmd_size
+= immutable_tgt
->per_io_data_size
;
555 md
->init_tio_pdu
= true;
558 err
= blk_mq_alloc_tag_set(md
->tag_set
);
560 goto out_kfree_tag_set
;
562 q
= blk_mq_init_allocated_queue(md
->tag_set
, md
->queue
);
571 blk_mq_free_tag_set(md
->tag_set
);
578 void dm_mq_cleanup_mapped_device(struct mapped_device
*md
)
581 blk_mq_free_tag_set(md
->tag_set
);
586 module_param(reserved_rq_based_ios
, uint
, S_IRUGO
| S_IWUSR
);
587 MODULE_PARM_DESC(reserved_rq_based_ios
, "Reserved IOs in request-based mempools");
589 /* Unused, but preserved for userspace compatibility */
590 static bool use_blk_mq
= true;
591 module_param(use_blk_mq
, bool, S_IRUGO
| S_IWUSR
);
592 MODULE_PARM_DESC(use_blk_mq
, "Use block multiqueue for request-based DM devices");
594 module_param(dm_mq_nr_hw_queues
, uint
, S_IRUGO
| S_IWUSR
);
595 MODULE_PARM_DESC(dm_mq_nr_hw_queues
, "Number of hardware queues for request-based dm-mq devices");
597 module_param(dm_mq_queue_depth
, uint
, S_IRUGO
| S_IWUSR
);
598 MODULE_PARM_DESC(dm_mq_queue_depth
, "Queue depth for request-based dm-mq devices");