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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2016 Red Hat, Inc. All rights reserved.4 *5 * This file is released under the GPL.6 */7 8#include "dm-core.h"9#include "dm-rq.h"10 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 */18struct 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 int n_sectors;28 unsigned int completed;29};30 31#define DM_MQ_NR_HW_QUEUES 132#define DM_MQ_QUEUE_DEPTH 204833static unsigned int dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;34static unsigned int 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 25640static unsigned int reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;41 42unsigned int dm_get_reserved_rq_based_ios(void)43{44 return __dm_get_module_param(&reserved_rq_based_ios,45 RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS);46}47 48static unsigned int dm_get_blk_mq_nr_hw_queues(void)49{50 return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);51}52 53static unsigned int dm_get_blk_mq_queue_depth(void)54{55 return __dm_get_module_param(&dm_mq_queue_depth,56 DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);57}58 59int dm_request_based(struct mapped_device *md)60{61 return queue_is_mq(md->queue);62}63 64void dm_start_queue(struct request_queue *q)65{66 blk_mq_unquiesce_queue(q);67 blk_mq_kick_requeue_list(q);68}69 70void dm_stop_queue(struct request_queue *q)71{72 blk_mq_quiesce_queue(q);73}74 75/*76 * Partial completion handling for request-based dm77 */78static void end_clone_bio(struct bio *clone)79{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;86 87 bio_put(clone);88 89 if (tio->error)90 /*91 * An error has already been detected on the request.92 * Once error occurred, just let clone->end_io() handle93 * the remainder.94 */95 return;96 else if (error) {97 /*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.101 */102 tio->error = error;103 goto exit;104 }105 106 /*107 * I/O for the bio successfully completed.108 * Notice the data completion to the upper layer.109 */110 tio->completed += nr_bytes;111 112 /*113 * Update the original request.114 * Do not use blk_mq_end_request() here, because it may complete115 * the original request before the clone, and break the ordering.116 */117 if (is_last)118 exit:119 blk_update_request(tio->orig, BLK_STS_OK, tio->completed);120}121 122static struct dm_rq_target_io *tio_from_request(struct request *rq)123{124 return blk_mq_rq_to_pdu(rq);125}126 127static void rq_end_stats(struct mapped_device *md, struct request *orig)128{129 if (unlikely(dm_stats_used(&md->stats))) {130 struct dm_rq_target_io *tio = tio_from_request(orig);131 132 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);136 }137}138 139/*140 * Don't touch any member of the md after calling this function because141 * 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 */144static void rq_completed(struct mapped_device *md)145{146 /*147 * dm_put() must be at the end of this function. See the comment above148 */149 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 */157static void dm_end_request(struct request *clone, blk_status_t error)158{159 struct dm_rq_target_io *tio = clone->end_io_data;160 struct mapped_device *md = tio->md;161 struct request *rq = tio->orig;162 163 blk_rq_unprep_clone(clone);164 tio->ti->type->release_clone_rq(clone, NULL);165 166 rq_end_stats(md, rq);167 blk_mq_end_request(rq, error);168 rq_completed(md);169}170 171static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs)172{173 blk_mq_delay_kick_requeue_list(q, msecs);174}175 176void dm_mq_kick_requeue_list(struct mapped_device *md)177{178 __dm_mq_kick_requeue_list(md->queue, 0);179}180EXPORT_SYMBOL(dm_mq_kick_requeue_list);181 182static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)183{184 blk_mq_requeue_request(rq, false);185 __dm_mq_kick_requeue_list(rq->q, msecs);186}187 188static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue)189{190 struct mapped_device *md = tio->md;191 struct request *rq = tio->orig;192 unsigned long delay_ms = delay_requeue ? 100 : 0;193 194 rq_end_stats(md, rq);195 if (tio->clone) {196 blk_rq_unprep_clone(tio->clone);197 tio->ti->type->release_clone_rq(tio->clone, NULL);198 }199 200 dm_mq_delay_requeue_request(rq, delay_ms);201 rq_completed(md);202}203 204static void dm_done(struct request *clone, blk_status_t error, bool mapped)205{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;209 210 if (tio->ti) {211 rq_end_io = tio->ti->type->rq_end_io;212 213 if (mapped && rq_end_io)214 r = rq_end_io(tio->ti, clone, error, &tio->info);215 }216 217 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);224 }225 226 switch (r) {227 case DM_ENDIO_DONE:228 /* The target wants to complete the I/O */229 dm_end_request(clone, error);230 break;231 case DM_ENDIO_INCOMPLETE:232 /* The target will handle the I/O */233 return;234 case DM_ENDIO_REQUEUE:235 /* The target wants to requeue the I/O */236 dm_requeue_original_request(tio, false);237 break;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);241 break;242 default:243 DMCRIT("unimplemented target endio return value: %d", r);244 BUG();245 }246}247 248/*249 * Request completion handler for request-based dm250 */251static void dm_softirq_done(struct request *rq)252{253 bool mapped = true;254 struct dm_rq_target_io *tio = tio_from_request(rq);255 struct request *clone = tio->clone;256 257 if (!clone) {258 struct mapped_device *md = tio->md;259 260 rq_end_stats(md, rq);261 blk_mq_end_request(rq, tio->error);262 rq_completed(md);263 return;264 }265 266 if (rq->rq_flags & RQF_FAILED)267 mapped = false;268 269 dm_done(clone, tio->error, mapped);270}271 272/*273 * Complete the clone and the original request with the error status274 * through softirq context.275 */276static void dm_complete_request(struct request *rq, blk_status_t error)277{278 struct dm_rq_target_io *tio = tio_from_request(rq);279 280 tio->error = error;281 if (likely(!blk_should_fake_timeout(rq->q)))282 blk_mq_complete_request(rq);283}284 285/*286 * Complete the not-mapped clone and the original request with the error status287 * 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.290 */291static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)292{293 rq->rq_flags |= RQF_FAILED;294 dm_complete_request(rq, error);295}296 297static enum rq_end_io_ret end_clone_request(struct request *clone,298 blk_status_t error)299{300 struct dm_rq_target_io *tio = clone->end_io_data;301 302 dm_complete_request(tio->orig, error);303 return RQ_END_IO_NONE;304}305 306static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,307 void *data)308{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);312 313 info->orig = bio_orig;314 info->tio = tio;315 bio->bi_end_io = end_clone_bio;316 317 return 0;318}319 320static int setup_clone(struct request *clone, struct request *rq,321 struct dm_rq_target_io *tio, gfp_t gfp_mask)322{323 int r;324 325 r = blk_rq_prep_clone(clone, rq, &tio->md->mempools->bs, gfp_mask,326 dm_rq_bio_constructor, tio);327 if (r)328 return r;329 330 clone->end_io = end_clone_request;331 clone->end_io_data = tio;332 333 tio->clone = clone;334 335 return 0;336}337 338static void init_tio(struct dm_rq_target_io *tio, struct request *rq,339 struct mapped_device *md)340{341 tio->md = md;342 tio->ti = NULL;343 tio->clone = NULL;344 tio->orig = rq;345 tio->error = 0;346 tio->completed = 0;347 /*348 * Avoid initializing info for blk-mq; it passes349 * target-specific data through info.ptr350 * (see: dm_mq_init_request)351 */352 if (!md->init_tio_pdu)353 memset(&tio->info, 0, sizeof(tio->info));354}355 356/*357 * Returns:358 * DM_MAPIO_* : the request has been processed as indicated359 * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued360 * < 0 : the request was completed due to failure361 */362static int map_request(struct dm_rq_target_io *tio)363{364 int r;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;369 blk_status_t ret;370 371 r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);372 switch (r) {373 case DM_MAPIO_SUBMITTED:374 /* The target has taken the I/O to submit by itself later */375 break;376 case DM_MAPIO_REMAPPED:377 if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {378 /* -ENOMEM */379 ti->type->release_clone_rq(clone, &tio->info);380 return DM_MAPIO_REQUEUE;381 }382 383 /* The target has remapped the I/O so dispatch it */384 trace_block_rq_remap(clone, disk_devt(dm_disk(md)),385 blk_rq_pos(rq));386 ret = blk_insert_cloned_request(clone);387 switch (ret) {388 case BLK_STS_OK:389 break;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);395 tio->clone = NULL;396 return DM_MAPIO_REQUEUE;397 default:398 /* must complete clone in terms of original request */399 dm_complete_request(rq, ret);400 }401 break;402 case DM_MAPIO_REQUEUE:403 /* The target wants to requeue the I/O */404 break;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);408 break;409 case DM_MAPIO_KILL:410 /* The target wants to complete the I/O */411 dm_kill_unmapped_request(rq, BLK_STS_IOERR);412 break;413 default:414 DMCRIT("unimplemented target map return value: %d", r);415 BUG();416 }417 418 return r;419}420 421/* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */422ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)423{424 return sprintf(buf, "%u\n", 0);425}426 427ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,428 const char *buf, size_t count)429{430 return count;431}432 433static void dm_start_request(struct mapped_device *md, struct request *orig)434{435 blk_mq_start_request(orig);436 437 if (unlikely(dm_stats_used(&md->stats))) {438 struct dm_rq_target_io *tio = tio_from_request(orig);439 440 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, 0,444 &tio->stats_aux);445 }446 447 /*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 completion451 * when all bios are completed.452 * See the comment in rq_completed() too.453 */454 dm_get(md);455}456 457static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,458 unsigned int hctx_idx, unsigned int numa_node)459{460 struct mapped_device *md = set->driver_data;461 struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);462 463 /*464 * Must initialize md member of tio, otherwise it won't465 * be available in dm_mq_queue_rq.466 */467 tio->md = md;468 469 if (md->init_tio_pdu) {470 /* target-specific per-io data is immediately after the tio */471 tio->info.ptr = tio + 1;472 }473 474 return 0;475}476 477static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,478 const struct blk_mq_queue_data *bd)479{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;484 485 /*486 * blk-mq's unquiesce may come from outside events, such as487 * elevator switch, updating nr_requests or others, and request may488 * come during suspend, so simply ask for blk-mq to requeue it.489 */490 if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)))491 return BLK_STS_RESOURCE;492 493 if (unlikely(!ti)) {494 int srcu_idx;495 struct dm_table *map;496 497 map = dm_get_live_table(md, &srcu_idx);498 if (unlikely(!map)) {499 DMERR_LIMIT("%s: mapping table unavailable, erroring io",500 dm_device_name(md));501 dm_put_live_table(md, srcu_idx);502 return BLK_STS_IOERR;503 }504 ti = dm_table_find_target(map, 0);505 dm_put_live_table(md, srcu_idx);506 }507 508 if (ti->type->busy && ti->type->busy(ti))509 return BLK_STS_RESOURCE;510 511 dm_start_request(md, rq);512 513 /* Init tio using md established in .init_request */514 init_tio(tio, rq, md);515 516 /*517 * Establish tio->ti before calling map_request().518 */519 tio->ti = ti;520 521 /* 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);525 rq_completed(md);526 return BLK_STS_RESOURCE;527 }528 529 return BLK_STS_OK;530}531 532static 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,536};537 538int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)539{540 struct dm_target *immutable_tgt;541 int err;542 543 md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);544 if (!md->tag_set)545 return -ENOMEM;546 547 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;553 554 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;560 }561 562 err = blk_mq_alloc_tag_set(md->tag_set);563 if (err)564 goto out_kfree_tag_set;565 566 err = blk_mq_init_allocated_queue(md->tag_set, md->queue);567 if (err)568 goto out_tag_set;569 return 0;570 571out_tag_set:572 blk_mq_free_tag_set(md->tag_set);573out_kfree_tag_set:574 kfree(md->tag_set);575 md->tag_set = NULL;576 577 return err;578}579 580void dm_mq_cleanup_mapped_device(struct mapped_device *md)581{582 if (md->tag_set) {583 blk_mq_free_tag_set(md->tag_set);584 kfree(md->tag_set);585 md->tag_set = NULL;586 }587}588 589module_param(reserved_rq_based_ios, uint, 0644);590MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");591 592/* Unused, but preserved for userspace compatibility */593static bool use_blk_mq = true;594module_param(use_blk_mq, bool, 0644);595MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");596 597module_param(dm_mq_nr_hw_queues, uint, 0644);598MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices");599 600module_param(dm_mq_queue_depth, uint, 0644);601MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");602