개념 설명 전체 · v6.18.37 / block/blk-mq.c
1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Block multiqueue core code 4 * 5 * Copyright (C) 2013-2014 Jens Axboe 6 * Copyright (C) 2013-2014 Christoph Hellwig 7 */ 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/backing-dev.h> 11 #include <linux/bio.h> 12 #include <linux/blkdev.h> 13 #include <linux/blk-integrity.h> 14 #include <linux/kmemleak.h> 15 #include <linux/mm.h> 16 #include <linux/init.h> 17 #include <linux/slab.h> 18 #include <linux/workqueue.h> 19 #include <linux/smp.h> 20 #include <linux/interrupt.h> 21 #include <linux/llist.h> 22 #include <linux/cpu.h> 23 #include <linux/cache.h> 24 #include <linux/sched/topology.h> 25 #include <linux/sched/signal.h> 26 #include <linux/suspend.h> 27 #include <linux/delay.h> 28 #include <linux/crash_dump.h> 29 #include <linux/prefetch.h> 30 #include <linux/blk-crypto.h> 31 #include <linux/part_stat.h> 32 #include <linux/sched/isolation.h> 33 34 #include <trace/events/block.h> 35 36 #include <linux/t10-pi.h> 37 #include "blk.h" 38 #include "blk-mq.h" 39 #include "blk-mq-debugfs.h" 40 #include "blk-pm.h" 41 #include "blk-stat.h" 42 #include "blk-mq-sched.h" 43 #include "blk-rq-qos.h" 44 45 static DEFINE_PER_CPU(struct llist_head, blk_cpu_done); 46 static DEFINE_PER_CPU(call_single_data_t, blk_cpu_csd); 47 static DEFINE_MUTEX(blk_mq_cpuhp_lock); 48 49 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags); 50 static void blk_mq_request_bypass_insert(struct request *rq, 51 blk_insert_t flags); 52 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, 53 struct list_head *list); 54 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx, 55 struct io_comp_batch *iob, unsigned int flags); 56 57 /* 58 * Check if any of the ctx, dispatch list or elevator 59 * have pending work in this hardware queue. 60 */ 61 static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) 62 { 63 return !list_empty_careful(&hctx->dispatch) || 64 sbitmap_any_bit_set(&hctx->ctx_map) || 65 blk_mq_sched_has_work(hctx); 66 } 67 68 /* 69 * Mark this ctx as having pending work in this hardware queue 70 */ 71 static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx, 72 struct blk_mq_ctx *ctx) 73 { 74 const int bit = ctx->index_hw[hctx->type]; 75 76 if (!sbitmap_test_bit(&hctx->ctx_map, bit)) 77 sbitmap_set_bit(&hctx->ctx_map, bit); 78 } 79 80 static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, 81 struct blk_mq_ctx *ctx) 82 { 83 const int bit = ctx->index_hw[hctx->type]; 84 85 sbitmap_clear_bit(&hctx->ctx_map, bit); 86 } 87 88 struct mq_inflight { 89 struct block_device *part; 90 unsigned int inflight[2]; 91 }; 92 93 static bool blk_mq_check_in_driver(struct request *rq, void *priv) 94 { 95 struct mq_inflight *mi = priv; 96 97 if (rq->rq_flags & RQF_IO_STAT && 98 (!bdev_is_partition(mi->part) || rq->part == mi->part) && 99 blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT) 100 mi->inflight[rq_data_dir(rq)]++; 101 102 return true; 103 } 104 105 void blk_mq_in_driver_rw(struct block_device *part, unsigned int inflight[2]) 106 { 107 struct mq_inflight mi = { .part = part }; 108 109 blk_mq_queue_tag_busy_iter(bdev_get_queue(part), blk_mq_check_in_driver, 110 &mi); 111 inflight[READ] = mi.inflight[READ]; 112 inflight[WRITE] = mi.inflight[WRITE]; 113 } 114 115 #ifdef CONFIG_LOCKDEP 116 static bool blk_freeze_set_owner(struct request_queue *q, 117 struct task_struct *owner) 118 { 119 if (!owner) 120 return false; 121 122 if (!q->mq_freeze_depth) { 123 q->mq_freeze_owner = owner; 124 q->mq_freeze_owner_depth = 1; 125 q->mq_freeze_disk_dead = !q->disk || 126 test_bit(GD_DEAD, &q->disk->state) || 127 !blk_queue_registered(q); 128 q->mq_freeze_queue_dying = blk_queue_dying(q); 129 return true; 130 } 131 132 if (owner == q->mq_freeze_owner) 133 q->mq_freeze_owner_depth += 1; 134 return false; 135 } 136 137 /* verify the last unfreeze in owner context */ 138 static bool blk_unfreeze_check_owner(struct request_queue *q) 139 { 140 if (q->mq_freeze_owner != current) 141 return false; 142 if (--q->mq_freeze_owner_depth == 0) { 143 q->mq_freeze_owner = NULL; 144 return true; 145 } 146 return false; 147 } 148 149 #else 150 151 static bool blk_freeze_set_owner(struct request_queue *q, 152 struct task_struct *owner) 153 { 154 return false; 155 } 156 157 static bool blk_unfreeze_check_owner(struct request_queue *q) 158 { 159 return false; 160 } 161 #endif 162 163 bool __blk_freeze_queue_start(struct request_queue *q, 164 struct task_struct *owner) 165 { 166 bool freeze; 167 168 mutex_lock(&q->mq_freeze_lock); 169 freeze = blk_freeze_set_owner(q, owner); 170 if (++q->mq_freeze_depth == 1) { 171 percpu_ref_kill(&q->q_usage_counter); 172 mutex_unlock(&q->mq_freeze_lock); 173 if (queue_is_mq(q)) 174 blk_mq_run_hw_queues(q, false); 175 } else { 176 mutex_unlock(&q->mq_freeze_lock); 177 } 178 179 return freeze; 180 } 181 182 void blk_freeze_queue_start(struct request_queue *q) 183 { 184 if (__blk_freeze_queue_start(q, current)) 185 blk_freeze_acquire_lock(q); 186 } 187 EXPORT_SYMBOL_GPL(blk_freeze_queue_start); 188 189 void blk_mq_freeze_queue_wait(struct request_queue *q) 190 { 191 wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter)); 192 } 193 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait); 194 195 int blk_mq_freeze_queue_wait_timeout(struct request_queue *q, 196 unsigned long timeout) 197 { 198 return wait_event_timeout(q->mq_freeze_wq, 199 percpu_ref_is_zero(&q->q_usage_counter), 200 timeout); 201 } 202 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout); 203 204 void blk_mq_freeze_queue_nomemsave(struct request_queue *q) 205 { 206 blk_freeze_queue_start(q); 207 blk_mq_freeze_queue_wait(q); 208 } 209 EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_nomemsave); 210 211 bool __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic) 212 { 213 bool unfreeze; 214 215 mutex_lock(&q->mq_freeze_lock); 216 if (force_atomic) 217 q->q_usage_counter.data->force_atomic = true; 218 q->mq_freeze_depth--; 219 WARN_ON_ONCE(q->mq_freeze_depth < 0); 220 if (!q->mq_freeze_depth) { 221 percpu_ref_resurrect(&q->q_usage_counter); 222 wake_up_all(&q->mq_freeze_wq); 223 } 224 unfreeze = blk_unfreeze_check_owner(q); 225 mutex_unlock(&q->mq_freeze_lock); 226 227 return unfreeze; 228 } 229 230 void blk_mq_unfreeze_queue_nomemrestore(struct request_queue *q) 231 { 232 if (__blk_mq_unfreeze_queue(q, false)) 233 blk_unfreeze_release_lock(q); 234 } 235 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue_nomemrestore); 236 237 /* 238 * non_owner variant of blk_freeze_queue_start 239 * 240 * Unlike blk_freeze_queue_start, the queue doesn't need to be unfrozen 241 * by the same task. This is fragile and should not be used if at all 242 * possible. 243 */ 244 void blk_freeze_queue_start_non_owner(struct request_queue *q) 245 { 246 __blk_freeze_queue_start(q, NULL); 247 } 248 EXPORT_SYMBOL_GPL(blk_freeze_queue_start_non_owner); 249 250 /* non_owner variant of blk_mq_unfreeze_queue */ 251 void blk_mq_unfreeze_queue_non_owner(struct request_queue *q) 252 { 253 __blk_mq_unfreeze_queue(q, false); 254 } 255 EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue_non_owner); 256 257 /* 258 * FIXME: replace the scsi_internal_device_*block_nowait() calls in the 259 * mpt3sas driver such that this function can be removed. 260 */ 261 void blk_mq_quiesce_queue_nowait(struct request_queue *q) 262 { 263 unsigned long flags; 264 265 spin_lock_irqsave(&q->queue_lock, flags); 266 if (!q->quiesce_depth++) 267 blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); 268 spin_unlock_irqrestore(&q->queue_lock, flags); 269 } 270 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); 271 272 /** 273 * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done 274 * @set: tag_set to wait on 275 * 276 * Note: it is driver's responsibility for making sure that quiesce has 277 * been started on or more of the request_queues of the tag_set. This 278 * function only waits for the quiesce on those request_queues that had 279 * the quiesce flag set using blk_mq_quiesce_queue_nowait. 280 */ 281 void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set) 282 { 283 if (set->flags & BLK_MQ_F_BLOCKING) 284 synchronize_srcu(set->srcu); 285 else 286 synchronize_rcu(); 287 } 288 EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done); 289 290 /** 291 * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished 292 * @q: request queue. 293 * 294 * Note: this function does not prevent that the struct request end_io() 295 * callback function is invoked. Once this function is returned, we make 296 * sure no dispatch can happen until the queue is unquiesced via 297 * blk_mq_unquiesce_queue(). 298 */ 299 void blk_mq_quiesce_queue(struct request_queue *q) 300 { 301 blk_mq_quiesce_queue_nowait(q); 302 /* nothing to wait for non-mq queues */ 303 if (queue_is_mq(q)) 304 blk_mq_wait_quiesce_done(q->tag_set); 305 } 306 EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); 307 308 /* 309 * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue() 310 * @q: request queue. 311 * 312 * This function recovers queue into the state before quiescing 313 * which is done by blk_mq_quiesce_queue. 314 */ 315 void blk_mq_unquiesce_queue(struct request_queue *q) 316 { 317 unsigned long flags; 318 bool run_queue = false; 319 320 spin_lock_irqsave(&q->queue_lock, flags); 321 if (WARN_ON_ONCE(q->quiesce_depth <= 0)) { 322 ; 323 } else if (!--q->quiesce_depth) { 324 blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); 325 run_queue = true; 326 } 327 spin_unlock_irqrestore(&q->queue_lock, flags); 328 329 /* dispatch requests which are inserted during quiescing */ 330 if (run_queue) 331 blk_mq_run_hw_queues(q, true); 332 } 333 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); 334 335 void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set) 336 { 337 struct request_queue *q; 338 339 rcu_read_lock(); 340 list_for_each_entry_rcu(q, &set->tag_list, tag_set_list) { 341 if (!blk_queue_skip_tagset_quiesce(q)) 342 blk_mq_quiesce_queue_nowait(q); 343 } 344 rcu_read_unlock(); 345 346 blk_mq_wait_quiesce_done(set); 347 } 348 EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset); 349 350 void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set) 351 { 352 struct request_queue *q; 353 354 rcu_read_lock(); 355 list_for_each_entry_rcu(q, &set->tag_list, tag_set_list) { 356 if (!blk_queue_skip_tagset_quiesce(q)) 357 blk_mq_unquiesce_queue(q); 358 } 359 rcu_read_unlock(); 360 } 361 EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset); 362 363 void blk_mq_wake_waiters(struct request_queue *q) 364 { 365 struct blk_mq_hw_ctx *hctx; 366 unsigned long i; 367 368 queue_for_each_hw_ctx(q, hctx, i) 369 if (blk_mq_hw_queue_mapped(hctx)) 370 blk_mq_tag_wakeup_all(hctx->tags, true); 371 } 372 373 void blk_rq_init(struct request_queue *q, struct request *rq) 374 { 375 memset(rq, 0, sizeof(*rq)); 376 377 INIT_LIST_HEAD(&rq->queuelist); 378 rq->q = q; 379 rq->__sector = (sector_t) -1; 380 INIT_HLIST_NODE(&rq->hash); 381 RB_CLEAR_NODE(&rq->rb_node); 382 rq->tag = BLK_MQ_NO_TAG; 383 rq->internal_tag = BLK_MQ_NO_TAG; 384 rq->start_time_ns = blk_time_get_ns(); 385 blk_crypto_rq_set_defaults(rq); 386 } 387 EXPORT_SYMBOL(blk_rq_init); 388 389 /* Set start and alloc time when the allocated request is actually used */ 390 static inline void blk_mq_rq_time_init(struct request *rq, u64 alloc_time_ns) 391 { 392 #ifdef CONFIG_BLK_RQ_ALLOC_TIME 393 if (blk_queue_rq_alloc_time(rq->q)) 394 rq->alloc_time_ns = alloc_time_ns; 395 else 396 rq->alloc_time_ns = 0; 397 #endif 398 } 399 400 static inline void blk_mq_bio_issue_init(struct request_queue *q, 401 struct bio *bio) 402 { 403 #ifdef CONFIG_BLK_CGROUP 404 if (test_bit(QUEUE_FLAG_BIO_ISSUE_TIME, &q->queue_flags)) 405 bio->issue_time_ns = blk_time_get_ns(); 406 #endif 407 } 408 409 static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, 410 struct blk_mq_tags *tags, unsigned int tag) 411 { 412 struct blk_mq_ctx *ctx = data->ctx; 413 struct blk_mq_hw_ctx *hctx = data->hctx; 414 struct request_queue *q = data->q; 415 struct request *rq = tags->static_rqs[tag]; 416 417 rq->q = q; 418 rq->mq_ctx = ctx; 419 rq->mq_hctx = hctx; 420 rq->cmd_flags = data->cmd_flags; 421 422 if (data->flags & BLK_MQ_REQ_PM) 423 data->rq_flags |= RQF_PM; 424 rq->rq_flags = data->rq_flags; 425 426 if (data->rq_flags & RQF_SCHED_TAGS) { 427 rq->tag = BLK_MQ_NO_TAG; 428 rq->internal_tag = tag; 429 } else { 430 rq->tag = tag; 431 rq->internal_tag = BLK_MQ_NO_TAG; 432 } 433 rq->timeout = 0; 434 435 rq->part = NULL; 436 rq->io_start_time_ns = 0; 437 rq->stats_sectors = 0; 438 rq->nr_phys_segments = 0; 439 rq->nr_integrity_segments = 0; 440 rq->end_io = NULL; 441 rq->end_io_data = NULL; 442 443 blk_crypto_rq_set_defaults(rq); 444 INIT_LIST_HEAD(&rq->queuelist); 445 /* tag was already set */ 446 WRITE_ONCE(rq->deadline, 0); 447 req_ref_set(rq, 1); 448 449 if (rq->rq_flags & RQF_USE_SCHED) { 450 struct elevator_queue *e = data->q->elevator; 451 452 INIT_HLIST_NODE(&rq->hash); 453 RB_CLEAR_NODE(&rq->rb_node); 454 455 if (e->type->ops.prepare_request) 456 e->type->ops.prepare_request(rq); 457 } 458 459 return rq; 460 } 461 462 static inline struct request * 463 __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data) 464 { 465 unsigned int tag, tag_offset; 466 struct blk_mq_tags *tags; 467 struct request *rq; 468 unsigned long tag_mask; 469 int i, nr = 0; 470 471 tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset); 472 if (unlikely(!tag_mask)) 473 return NULL; 474 475 tags = blk_mq_tags_from_data(data); 476 for (i = 0; tag_mask; i++) { 477 if (!(tag_mask & (1UL << i))) 478 continue; 479 tag = tag_offset + i; 480 prefetch(tags->static_rqs[tag]); 481 tag_mask &= ~(1UL << i); 482 rq = blk_mq_rq_ctx_init(data, tags, tag); 483 rq_list_add_head(data->cached_rqs, rq); 484 nr++; 485 } 486 if (!(data->rq_flags & RQF_SCHED_TAGS)) 487 blk_mq_add_active_requests(data->hctx, nr); 488 /* caller already holds a reference, add for remainder */ 489 percpu_ref_get_many(&data->q->q_usage_counter, nr - 1); 490 data->nr_tags -= nr; 491 492 return rq_list_pop(data->cached_rqs); 493 } 494 495 static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data) 496 { 497 struct request_queue *q = data->q; 498 u64 alloc_time_ns = 0; 499 struct request *rq; 500 unsigned int tag; 501 502 /* alloc_time includes depth and tag waits */ 503 if (blk_queue_rq_alloc_time(q)) 504 alloc_time_ns = blk_time_get_ns(); 505 506 if (data->cmd_flags & REQ_NOWAIT) 507 data->flags |= BLK_MQ_REQ_NOWAIT; 508 509 retry: 510 data->ctx = blk_mq_get_ctx(q); 511 data->hctx = blk_mq_map_queue(data->cmd_flags, data->ctx); 512 513 if (q->elevator) { 514 /* 515 * All requests use scheduler tags when an I/O scheduler is 516 * enabled for the queue. 517 */ 518 data->rq_flags |= RQF_SCHED_TAGS; 519 520 /* 521 * Flush/passthrough requests are special and go directly to the 522 * dispatch list. 523 */ 524 if ((data->cmd_flags & REQ_OP_MASK) != REQ_OP_FLUSH && 525 !blk_op_is_passthrough(data->cmd_flags)) { 526 struct elevator_mq_ops *ops = &q->elevator->type->ops; 527 528 WARN_ON_ONCE(data->flags & BLK_MQ_REQ_RESERVED); 529 530 data->rq_flags |= RQF_USE_SCHED; 531 if (ops->limit_depth) 532 ops->limit_depth(data->cmd_flags, data); 533 } 534 } else { 535 blk_mq_tag_busy(data->hctx); 536 } 537 538 if (data->flags & BLK_MQ_REQ_RESERVED) 539 data->rq_flags |= RQF_RESV; 540 541 /* 542 * Try batched alloc if we want more than 1 tag. 543 */ 544 if (data->nr_tags > 1) { 545 rq = __blk_mq_alloc_requests_batch(data); 546 if (rq) { 547 blk_mq_rq_time_init(rq, alloc_time_ns); 548 return rq; 549 } 550 data->nr_tags = 1; 551 } 552 553 /* 554 * Waiting allocations only fail because of an inactive hctx. In that 555 * case just retry the hctx assignment and tag allocation as CPU hotplug 556 * should have migrated us to an online CPU by now. 557 */ 558 tag = blk_mq_get_tag(data); 559 if (tag == BLK_MQ_NO_TAG) { 560 if (data->flags & BLK_MQ_REQ_NOWAIT) 561 return NULL; 562 /* 563 * Give up the CPU and sleep for a random short time to 564 * ensure that thread using a realtime scheduling class 565 * are migrated off the CPU, and thus off the hctx that 566 * is going away. 567 */ 568 msleep(3); 569 goto retry; 570 } 571 572 if (!(data->rq_flags & RQF_SCHED_TAGS)) 573 blk_mq_inc_active_requests(data->hctx); 574 rq = blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag); 575 blk_mq_rq_time_init(rq, alloc_time_ns); 576 return rq; 577 } 578 579 static struct request *blk_mq_rq_cache_fill(struct request_queue *q, 580 struct blk_plug *plug, 581 blk_opf_t opf, 582 blk_mq_req_flags_t flags) 583 { 584 struct blk_mq_alloc_data data = { 585 .q = q, 586 .flags = flags, 587 .shallow_depth = 0, 588 .cmd_flags = opf, 589 .rq_flags = 0, 590 .nr_tags = plug->nr_ios, 591 .cached_rqs = &plug->cached_rqs, 592 .ctx = NULL, 593 .hctx = NULL 594 }; 595 struct request *rq; 596 597 if (blk_queue_enter(q, flags)) 598 return NULL; 599 600 plug->nr_ios = 1; 601 602 rq = __blk_mq_alloc_requests(&data); 603 if (unlikely(!rq)) 604 blk_queue_exit(q); 605 return rq; 606 } 607 608 static struct request *blk_mq_alloc_cached_request(struct request_queue *q, 609 blk_opf_t opf, 610 blk_mq_req_flags_t flags) 611 { 612 struct blk_plug *plug = current->plug; 613 struct request *rq; 614 615 if (!plug) 616 return NULL; 617 618 if (rq_list_empty(&plug->cached_rqs)) { 619 if (plug->nr_ios == 1) 620 return NULL; 621 rq = blk_mq_rq_cache_fill(q, plug, opf, flags); 622 if (!rq) 623 return NULL; 624 } else { 625 rq = rq_list_peek(&plug->cached_rqs); 626 if (!rq || rq->q != q) 627 return NULL; 628 629 if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type) 630 return NULL; 631 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf)) 632 return NULL; 633 634 rq_list_pop(&plug->cached_rqs); 635 blk_mq_rq_time_init(rq, blk_time_get_ns()); 636 } 637 638 rq->cmd_flags = opf; 639 INIT_LIST_HEAD(&rq->queuelist); 640 return rq; 641 } 642 643 struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf, 644 blk_mq_req_flags_t flags) 645 { 646 struct request *rq; 647 648 rq = blk_mq_alloc_cached_request(q, opf, flags); 649 if (!rq) { 650 struct blk_mq_alloc_data data = { 651 .q = q, 652 .flags = flags, 653 .shallow_depth = 0, 654 .cmd_flags = opf, 655 .rq_flags = 0, 656 .nr_tags = 1, 657 .cached_rqs = NULL, 658 .ctx = NULL, 659 .hctx = NULL 660 }; 661 int ret; 662 663 ret = blk_queue_enter(q, flags); 664 if (ret) 665 return ERR_PTR(ret); 666 667 rq = __blk_mq_alloc_requests(&data); 668 if (!rq) 669 goto out_queue_exit; 670 } 671 rq->__data_len = 0; 672 rq->__sector = (sector_t) -1; 673 rq->bio = rq->biotail = NULL; 674 return rq; 675 out_queue_exit: 676 blk_queue_exit(q); 677 return ERR_PTR(-EWOULDBLOCK); 678 } 679 EXPORT_SYMBOL(blk_mq_alloc_request); 680 681 struct request *blk_mq_alloc_request_hctx(struct request_queue *q, 682 blk_opf_t opf, blk_mq_req_flags_t flags, unsigned int hctx_idx) 683 { 684 struct blk_mq_alloc_data data = { 685 .q = q, 686 .flags = flags, 687 .shallow_depth = 0, 688 .cmd_flags = opf, 689 .rq_flags = 0, 690 .nr_tags = 1, 691 .cached_rqs = NULL, 692 .ctx = NULL, 693 .hctx = NULL 694 }; 695 u64 alloc_time_ns = 0; 696 struct request *rq; 697 unsigned int cpu; 698 unsigned int tag; 699 int ret; 700 701 /* alloc_time includes depth and tag waits */ 702 if (blk_queue_rq_alloc_time(q)) 703 alloc_time_ns = blk_time_get_ns(); 704 705 /* 706 * If the tag allocator sleeps we could get an allocation for a 707 * different hardware context. No need to complicate the low level 708 * allocator for this for the rare use case of a command tied to 709 * a specific queue. 710 */ 711 if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)) || 712 WARN_ON_ONCE(!(flags & BLK_MQ_REQ_RESERVED))) 713 return ERR_PTR(-EINVAL); 714 715 if (hctx_idx >= q->nr_hw_queues) 716 return ERR_PTR(-EIO); 717 718 ret = blk_queue_enter(q, flags); 719 if (ret) 720 return ERR_PTR(ret); 721 722 /* 723 * Check if the hardware context is actually mapped to anything. 724 * If not tell the caller that it should skip this queue. 725 */ 726 ret = -EXDEV; 727 data.hctx = xa_load(&q->hctx_table, hctx_idx); 728 if (!blk_mq_hw_queue_mapped(data.hctx)) 729 goto out_queue_exit; 730 cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask); 731 if (cpu >= nr_cpu_ids) 732 goto out_queue_exit; 733 data.ctx = __blk_mq_get_ctx(q, cpu); 734 735 if (q->elevator) 736 data.rq_flags |= RQF_SCHED_TAGS; 737 else 738 blk_mq_tag_busy(data.hctx); 739 740 if (flags & BLK_MQ_REQ_RESERVED) 741 data.rq_flags |= RQF_RESV; 742 743 ret = -EWOULDBLOCK; 744 tag = blk_mq_get_tag(&data); 745 if (tag == BLK_MQ_NO_TAG) 746 goto out_queue_exit; 747 if (!(data.rq_flags & RQF_SCHED_TAGS)) 748 blk_mq_inc_active_requests(data.hctx); 749 rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag); 750 blk_mq_rq_time_init(rq, alloc_time_ns); 751 rq->__data_len = 0; 752 rq->__sector = (sector_t) -1; 753 rq->bio = rq->biotail = NULL; 754 return rq; 755 756 out_queue_exit: 757 blk_queue_exit(q); 758 return ERR_PTR(ret); 759 } 760 EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx); 761 762 static void blk_mq_finish_request(struct request *rq) 763 { 764 struct request_queue *q = rq->q; 765 766 blk_zone_finish_request(rq); 767 768 if (rq->rq_flags & RQF_USE_SCHED) { 769 q->elevator->type->ops.finish_request(rq); 770 /* 771 * For postflush request that may need to be 772 * completed twice, we should clear this flag 773 * to avoid double finish_request() on the rq. 774 */ 775 rq->rq_flags &= ~RQF_USE_SCHED; 776 } 777 } 778 779 static void __blk_mq_free_request(struct request *rq) 780 { 781 struct request_queue *q = rq->q; 782 struct blk_mq_ctx *ctx = rq->mq_ctx; 783 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 784 const int sched_tag = rq->internal_tag; 785 786 blk_crypto_free_request(rq); 787 blk_pm_mark_last_busy(rq); 788 rq->mq_hctx = NULL; 789 790 if (rq->tag != BLK_MQ_NO_TAG) { 791 blk_mq_dec_active_requests(hctx); 792 blk_mq_put_tag(hctx->tags, ctx, rq->tag); 793 } 794 if (sched_tag != BLK_MQ_NO_TAG) 795 blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag); 796 blk_mq_sched_restart(hctx); 797 blk_queue_exit(q); 798 } 799 800 void blk_mq_free_request(struct request *rq) 801 { 802 struct request_queue *q = rq->q; 803 804 blk_mq_finish_request(rq); 805 806 if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq))) 807 laptop_io_completion(q->disk->bdi); 808 809 rq_qos_done(q, rq); 810 811 WRITE_ONCE(rq->state, MQ_RQ_IDLE); 812 if (req_ref_put_and_test(rq)) 813 __blk_mq_free_request(rq); 814 } 815 EXPORT_SYMBOL_GPL(blk_mq_free_request); 816 817 void blk_mq_free_plug_rqs(struct blk_plug *plug) 818 { 819 struct request *rq; 820 821 while ((rq = rq_list_pop(&plug->cached_rqs)) != NULL) 822 blk_mq_free_request(rq); 823 } 824 825 void blk_dump_rq_flags(struct request *rq, char *msg) 826 { 827 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg, 828 rq->q->disk ? rq->q->disk->disk_name : "?", 829 (__force unsigned long long) rq->cmd_flags); 830 831 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", 832 (unsigned long long)blk_rq_pos(rq), 833 blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); 834 printk(KERN_INFO " bio %p, biotail %p, len %u\n", 835 rq->bio, rq->biotail, blk_rq_bytes(rq)); 836 } 837 EXPORT_SYMBOL(blk_dump_rq_flags); 838 839 static void blk_account_io_completion(struct request *req, unsigned int bytes) 840 { 841 if (req->rq_flags & RQF_IO_STAT) { 842 const int sgrp = op_stat_group(req_op(req)); 843 844 part_stat_lock(); 845 part_stat_add(req->part, sectors[sgrp], bytes >> 9); 846 part_stat_unlock(); 847 } 848 } 849 850 static void blk_print_req_error(struct request *req, blk_status_t status) 851 { 852 printk_ratelimited(KERN_ERR 853 "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x " 854 "phys_seg %u prio class %u\n", 855 blk_status_to_str(status), 856 req->q->disk ? req->q->disk->disk_name : "?", 857 blk_rq_pos(req), (__force u32)req_op(req), 858 blk_op_str(req_op(req)), 859 (__force u32)(req->cmd_flags & ~REQ_OP_MASK), 860 req->nr_phys_segments, 861 IOPRIO_PRIO_CLASS(req_get_ioprio(req))); 862 } 863 864 /* 865 * Fully end IO on a request. Does not support partial completions, or 866 * errors. 867 */ 868 static void blk_complete_request(struct request *req) 869 { 870 const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0; 871 int total_bytes = blk_rq_bytes(req); 872 struct bio *bio = req->bio; 873 874 trace_block_rq_complete(req, BLK_STS_OK, total_bytes); 875 876 if (!bio) 877 return; 878 879 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ) 880 blk_integrity_complete(req, total_bytes); 881 882 /* 883 * Upper layers may call blk_crypto_evict_key() anytime after the last 884 * bio_endio(). Therefore, the keyslot must be released before that. 885 */ 886 blk_crypto_rq_put_keyslot(req); 887 888 blk_account_io_completion(req, total_bytes); 889 890 do { 891 struct bio *next = bio->bi_next; 892 893 /* Completion has already been traced */ 894 bio_clear_flag(bio, BIO_TRACE_COMPLETION); 895 896 if (blk_req_bio_is_zone_append(req, bio)) 897 blk_zone_append_update_request_bio(req, bio); 898 899 if (!is_flush) 900 bio_endio(bio); 901 bio = next; 902 } while (bio); 903 904 /* 905 * Reset counters so that the request stacking driver 906 * can find how many bytes remain in the request 907 * later. 908 */ 909 if (!req->end_io) { 910 req->bio = NULL; 911 req->__data_len = 0; 912 } 913 } 914 915 /** 916 * blk_update_request - Complete multiple bytes without completing the request 917 * @req: the request being processed 918 * @error: block status code 919 * @nr_bytes: number of bytes to complete for @req 920 * 921 * Description: 922 * Ends I/O on a number of bytes attached to @req, but doesn't complete 923 * the request structure even if @req doesn't have leftover. 924 * If @req has leftover, sets it up for the next range of segments. 925 * 926 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees 927 * %false return from this function. 928 * 929 * Note: 930 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in this function 931 * except in the consistency check at the end of this function. 932 * 933 * Return: 934 * %false - this request doesn't have any more data 935 * %true - this request has more data 936 **/ 937 bool blk_update_request(struct request *req, blk_status_t error, 938 unsigned int nr_bytes) 939 { 940 bool is_flush = req->rq_flags & RQF_FLUSH_SEQ; 941 bool quiet = req->rq_flags & RQF_QUIET; 942 int total_bytes; 943 944 trace_block_rq_complete(req, error, nr_bytes); 945 946 if (!req->bio) 947 return false; 948 949 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ && 950 error == BLK_STS_OK) 951 blk_integrity_complete(req, nr_bytes); 952 953 /* 954 * Upper layers may call blk_crypto_evict_key() anytime after the last 955 * bio_endio(). Therefore, the keyslot must be released before that. 956 */ 957 if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req)) 958 __blk_crypto_rq_put_keyslot(req); 959 960 if (unlikely(error && !blk_rq_is_passthrough(req) && !quiet) && 961 !test_bit(GD_DEAD, &req->q->disk->state)) { 962 blk_print_req_error(req, error); 963 trace_block_rq_error(req, error, nr_bytes); 964 } 965 966 blk_account_io_completion(req, nr_bytes); 967 968 total_bytes = 0; 969 while (req->bio) { 970 struct bio *bio = req->bio; 971 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); 972 973 if (unlikely(error)) 974 bio->bi_status = error; 975 976 if (bio_bytes == bio->bi_iter.bi_size) { 977 req->bio = bio->bi_next; 978 } else if (bio_is_zone_append(bio) && error == BLK_STS_OK) { 979 /* 980 * Partial zone append completions cannot be supported 981 * as the BIO fragments may end up not being written 982 * sequentially. 983 */ 984 bio->bi_status = BLK_STS_IOERR; 985 } 986 987 /* Completion has already been traced */ 988 bio_clear_flag(bio, BIO_TRACE_COMPLETION); 989 if (unlikely(quiet)) 990 bio_set_flag(bio, BIO_QUIET); 991 992 bio_advance(bio, bio_bytes); 993 994 /* Don't actually finish bio if it's part of flush sequence */ 995 if (!bio->bi_iter.bi_size) { 996 if (blk_req_bio_is_zone_append(req, bio)) 997 blk_zone_append_update_request_bio(req, bio); 998 if (!is_flush) 999 bio_endio(bio); 1000 } 1001 1002 total_bytes += bio_bytes; 1003 nr_bytes -= bio_bytes; 1004 1005 if (!nr_bytes) 1006 break; 1007 } 1008 1009 /* 1010 * completely done 1011 */ 1012 if (!req->bio) { 1013 /* 1014 * Reset counters so that the request stacking driver 1015 * can find how many bytes remain in the request 1016 * later. 1017 */ 1018 req->__data_len = 0; 1019 return false; 1020 } 1021 1022 req->__data_len -= total_bytes; 1023 1024 /* update sector only for requests with clear definition of sector */ 1025 if (!blk_rq_is_passthrough(req)) 1026 req->__sector += total_bytes >> 9; 1027 1028 /* mixed attributes always follow the first bio */ 1029 if (req->rq_flags & RQF_MIXED_MERGE) { 1030 req->cmd_flags &= ~REQ_FAILFAST_MASK; 1031 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; 1032 } 1033 1034 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { 1035 /* 1036 * If total number of sectors is less than the first segment 1037 * size, something has gone terribly wrong. 1038 */ 1039 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { 1040 blk_dump_rq_flags(req, "request botched"); 1041 req->__data_len = blk_rq_cur_bytes(req); 1042 } 1043 1044 /* recalculate the number of segments */ 1045 req->nr_phys_segments = blk_recalc_rq_segments(req); 1046 } 1047 1048 return true; 1049 } 1050 EXPORT_SYMBOL_GPL(blk_update_request); 1051 1052 static inline void blk_account_io_done(struct request *req, u64 now) 1053 { 1054 trace_block_io_done(req); 1055 1056 /* 1057 * Account IO completion. flush_rq isn't accounted as a 1058 * normal IO on queueing nor completion. Accounting the 1059 * containing request is enough. 1060 */ 1061 if ((req->rq_flags & (RQF_IO_STAT|RQF_FLUSH_SEQ)) == RQF_IO_STAT) { 1062 const int sgrp = op_stat_group(req_op(req)); 1063 1064 part_stat_lock(); 1065 update_io_ticks(req->part, jiffies, true); 1066 part_stat_inc(req->part, ios[sgrp]); 1067 part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns); 1068 part_stat_local_dec(req->part, 1069 in_flight[op_is_write(req_op(req))]); 1070 part_stat_unlock(); 1071 } 1072 } 1073 1074 static inline bool blk_rq_passthrough_stats(struct request *req) 1075 { 1076 struct bio *bio = req->bio; 1077 1078 if (!blk_queue_passthrough_stat(req->q)) 1079 return false; 1080 1081 /* Requests without a bio do not transfer data. */ 1082 if (!bio) 1083 return false; 1084 1085 /* 1086 * Stats are accumulated in the bdev, so must have one attached to a 1087 * bio to track stats. Most drivers do not set the bdev for passthrough 1088 * requests, but nvme is one that will set it. 1089 */ 1090 if (!bio->bi_bdev) 1091 return false; 1092 1093 /* 1094 * We don't know what a passthrough command does, but we know the 1095 * payload size and data direction. Ensuring the size is aligned to the 1096 * block size filters out most commands with payloads that don't 1097 * represent sector access. 1098 */ 1099 if (blk_rq_bytes(req) & (bdev_logical_block_size(bio->bi_bdev) - 1)) 1100 return false; 1101 return true; 1102 } 1103 1104 static inline void blk_account_io_start(struct request *req) 1105 { 1106 trace_block_io_start(req); 1107 1108 if (!blk_queue_io_stat(req->q)) 1109 return; 1110 if (blk_rq_is_passthrough(req) && !blk_rq_passthrough_stats(req)) 1111 return; 1112 1113 req->rq_flags |= RQF_IO_STAT; 1114 req->start_time_ns = blk_time_get_ns(); 1115 1116 /* 1117 * All non-passthrough requests are created from a bio with one 1118 * exception: when a flush command that is part of a flush sequence 1119 * generated by the state machine in blk-flush.c is cloned onto the 1120 * lower device by dm-multipath we can get here without a bio. 1121 */ 1122 if (req->bio) 1123 req->part = req->bio->bi_bdev; 1124 else 1125 req->part = req->q->disk->part0; 1126 1127 part_stat_lock(); 1128 update_io_ticks(req->part, jiffies, false); 1129 part_stat_local_inc(req->part, in_flight[op_is_write(req_op(req))]); 1130 part_stat_unlock(); 1131 } 1132 1133 static inline void __blk_mq_end_request_acct(struct request *rq, u64 now) 1134 { 1135 if (rq->rq_flags & RQF_STATS) 1136 blk_stat_add(rq, now); 1137 1138 blk_mq_sched_completed_request(rq, now); 1139 blk_account_io_done(rq, now); 1140 } 1141 1142 inline void __blk_mq_end_request(struct request *rq, blk_status_t error) 1143 { 1144 if (blk_mq_need_time_stamp(rq)) 1145 __blk_mq_end_request_acct(rq, blk_time_get_ns()); 1146 1147 blk_mq_finish_request(rq); 1148 1149 if (rq->end_io) { 1150 rq_qos_done(rq->q, rq); 1151 if (rq->end_io(rq, error) == RQ_END_IO_FREE) 1152 blk_mq_free_request(rq); 1153 } else { 1154 blk_mq_free_request(rq); 1155 } 1156 } 1157 EXPORT_SYMBOL(__blk_mq_end_request); 1158 1159 void blk_mq_end_request(struct request *rq, blk_status_t error) 1160 { 1161 if (blk_update_request(rq, error, blk_rq_bytes(rq))) 1162 BUG(); 1163 __blk_mq_end_request(rq, error); 1164 } 1165 EXPORT_SYMBOL(blk_mq_end_request); 1166 1167 #define TAG_COMP_BATCH 32 1168 1169 static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx, 1170 int *tag_array, int nr_tags) 1171 { 1172 struct request_queue *q = hctx->queue; 1173 1174 blk_mq_sub_active_requests(hctx, nr_tags); 1175 1176 blk_mq_put_tags(hctx->tags, tag_array, nr_tags); 1177 percpu_ref_put_many(&q->q_usage_counter, nr_tags); 1178 } 1179 1180 void blk_mq_end_request_batch(struct io_comp_batch *iob) 1181 { 1182 int tags[TAG_COMP_BATCH], nr_tags = 0; 1183 struct blk_mq_hw_ctx *cur_hctx = NULL; 1184 struct request *rq; 1185 u64 now = 0; 1186 1187 if (iob->need_ts) 1188 now = blk_time_get_ns(); 1189 1190 while ((rq = rq_list_pop(&iob->req_list)) != NULL) { 1191 prefetch(rq->bio); 1192 prefetch(rq->rq_next); 1193 1194 blk_complete_request(rq); 1195 if (iob->need_ts) 1196 __blk_mq_end_request_acct(rq, now); 1197 1198 blk_mq_finish_request(rq); 1199 1200 rq_qos_done(rq->q, rq); 1201 1202 /* 1203 * If end_io handler returns NONE, then it still has 1204 * ownership of the request. 1205 */ 1206 if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE) 1207 continue; 1208 1209 WRITE_ONCE(rq->state, MQ_RQ_IDLE); 1210 if (!req_ref_put_and_test(rq)) 1211 continue; 1212 1213 blk_crypto_free_request(rq); 1214 blk_pm_mark_last_busy(rq); 1215 1216 if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) { 1217 if (cur_hctx) 1218 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags); 1219 nr_tags = 0; 1220 cur_hctx = rq->mq_hctx; 1221 } 1222 tags[nr_tags++] = rq->tag; 1223 } 1224 1225 if (nr_tags) 1226 blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags); 1227 } 1228 EXPORT_SYMBOL_GPL(blk_mq_end_request_batch); 1229 1230 static void blk_complete_reqs(struct llist_head *list) 1231 { 1232 struct llist_node *entry = llist_reverse_order(llist_del_all(list)); 1233 struct request *rq, *next; 1234 1235 llist_for_each_entry_safe(rq, next, entry, ipi_list) 1236 rq->q->mq_ops->complete(rq); 1237 } 1238 1239 static __latent_entropy void blk_done_softirq(void) 1240 { 1241 blk_complete_reqs(this_cpu_ptr(&blk_cpu_done)); 1242 } 1243 1244 static int blk_softirq_cpu_dead(unsigned int cpu) 1245 { 1246 blk_complete_reqs(&per_cpu(blk_cpu_done, cpu)); 1247 return 0; 1248 } 1249 1250 static void __blk_mq_complete_request_remote(void *data) 1251 { 1252 __raise_softirq_irqoff(BLOCK_SOFTIRQ); 1253 } 1254 1255 static inline bool blk_mq_complete_need_ipi(struct request *rq) 1256 { 1257 int cpu = raw_smp_processor_id(); 1258 1259 if (!IS_ENABLED(CONFIG_SMP) || 1260 !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) 1261 return false; 1262 /* 1263 * With force threaded interrupts enabled, raising softirq from an SMP 1264 * function call will always result in waking the ksoftirqd thread. 1265 * This is probably worse than completing the request on a different 1266 * cache domain. 1267 */ 1268 if (force_irqthreads()) 1269 return false; 1270 1271 /* same CPU or cache domain and capacity? Complete locally */ 1272 if (cpu == rq->mq_ctx->cpu || 1273 (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) && 1274 cpus_share_cache(cpu, rq->mq_ctx->cpu) && 1275 cpus_equal_capacity(cpu, rq->mq_ctx->cpu))) 1276 return false; 1277 1278 /* don't try to IPI to an offline CPU */ 1279 return cpu_online(rq->mq_ctx->cpu); 1280 } 1281 1282 static void blk_mq_complete_send_ipi(struct request *rq) 1283 { 1284 unsigned int cpu; 1285 1286 cpu = rq->mq_ctx->cpu; 1287 if (llist_add(&rq->ipi_list, &per_cpu(blk_cpu_done, cpu))) 1288 smp_call_function_single_async(cpu, &per_cpu(blk_cpu_csd, cpu)); 1289 } 1290 1291 static void blk_mq_raise_softirq(struct request *rq) 1292 { 1293 struct llist_head *list; 1294 1295 preempt_disable(); 1296 list = this_cpu_ptr(&blk_cpu_done); 1297 if (llist_add(&rq->ipi_list, list)) 1298 raise_softirq(BLOCK_SOFTIRQ); 1299 preempt_enable(); 1300 } 1301 1302 bool blk_mq_complete_request_remote(struct request *rq) 1303 { 1304 WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); 1305 1306 /* 1307 * For request which hctx has only one ctx mapping, 1308 * or a polled request, always complete locally, 1309 * it's pointless to redirect the completion. 1310 */ 1311 if ((rq->mq_hctx->nr_ctx == 1 && 1312 rq->mq_ctx->cpu == raw_smp_processor_id()) || 1313 rq->cmd_flags & REQ_POLLED) 1314 return false; 1315 1316 if (blk_mq_complete_need_ipi(rq)) { 1317 blk_mq_complete_send_ipi(rq); 1318 return true; 1319 } 1320 1321 if (rq->q->nr_hw_queues == 1) { 1322 blk_mq_raise_softirq(rq); 1323 return true; 1324 } 1325 return false; 1326 } 1327 EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote); 1328 1329 /** 1330 * blk_mq_complete_request - end I/O on a request 1331 * @rq: the request being processed 1332 * 1333 * Description: 1334 * Complete a request by scheduling the ->complete_rq operation. 1335 **/ 1336 void blk_mq_complete_request(struct request *rq) 1337 { 1338 if (!blk_mq_complete_request_remote(rq)) 1339 rq->q->mq_ops->complete(rq); 1340 } 1341 EXPORT_SYMBOL(blk_mq_complete_request); 1342 1343 /** 1344 * blk_mq_start_request - Start processing a request 1345 * @rq: Pointer to request to be started 1346 * 1347 * Function used by device drivers to notify the block layer that a request 1348 * is going to be processed now, so blk layer can do proper initializations 1349 * such as starting the timeout timer. 1350 */ 1351 void blk_mq_start_request(struct request *rq) 1352 { 1353 struct request_queue *q = rq->q; 1354 1355 trace_block_rq_issue(rq); 1356 1357 if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags) && 1358 !blk_rq_is_passthrough(rq)) { 1359 rq->io_start_time_ns = blk_time_get_ns(); 1360 rq->stats_sectors = blk_rq_sectors(rq); 1361 rq->rq_flags |= RQF_STATS; 1362 rq_qos_issue(q, rq); 1363 } 1364 1365 WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE); 1366 1367 blk_add_timer(rq); 1368 WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT); 1369 rq->mq_hctx->tags->rqs[rq->tag] = rq; 1370 1371 if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE) 1372 blk_integrity_prepare(rq); 1373 1374 if (rq->bio && rq->bio->bi_opf & REQ_POLLED) 1375 WRITE_ONCE(rq->bio->bi_cookie, rq->mq_hctx->queue_num); 1376 } 1377 EXPORT_SYMBOL(blk_mq_start_request); 1378 1379 /* 1380 * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple 1381 * queues. This is important for md arrays to benefit from merging 1382 * requests. 1383 */ 1384 static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug) 1385 { 1386 if (plug->multiple_queues) 1387 return BLK_MAX_REQUEST_COUNT * 2; 1388 return BLK_MAX_REQUEST_COUNT; 1389 } 1390 1391 static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) 1392 { 1393 struct request *last = rq_list_peek(&plug->mq_list); 1394 1395 if (!plug->rq_count) { 1396 trace_block_plug(rq->q); 1397 } else if (plug->rq_count >= blk_plug_max_rq_count(plug) || 1398 (!blk_queue_nomerges(rq->q) && 1399 blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { 1400 blk_mq_flush_plug_list(plug, false); 1401 last = NULL; 1402 trace_block_plug(rq->q); 1403 } 1404 1405 if (!plug->multiple_queues && last && last->q != rq->q) 1406 plug->multiple_queues = true; 1407 /* 1408 * Any request allocated from sched tags can't be issued to 1409 * ->queue_rqs() directly 1410 */ 1411 if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS)) 1412 plug->has_elevator = true; 1413 rq_list_add_tail(&plug->mq_list, rq); 1414 plug->rq_count++; 1415 } 1416 1417 /** 1418 * blk_execute_rq_nowait - insert a request to I/O scheduler for execution 1419 * @rq: request to insert 1420 * @at_head: insert request at head or tail of queue 1421 * 1422 * Description: 1423 * Insert a fully prepared request at the back of the I/O scheduler queue 1424 * for execution. Don't wait for completion. 1425 * 1426 * Note: 1427 * This function will invoke @done directly if the queue is dead. 1428 */ 1429 void blk_execute_rq_nowait(struct request *rq, bool at_head) 1430 { 1431 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 1432 1433 WARN_ON(irqs_disabled()); 1434 WARN_ON(!blk_rq_is_passthrough(rq)); 1435 1436 blk_account_io_start(rq); 1437 1438 if (current->plug && !at_head) { 1439 blk_add_rq_to_plug(current->plug, rq); 1440 return; 1441 } 1442 1443 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0); 1444 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING); 1445 } 1446 EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); 1447 1448 struct blk_rq_wait { 1449 struct completion done; 1450 blk_status_t ret; 1451 }; 1452 1453 static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret) 1454 { 1455 struct blk_rq_wait *wait = rq->end_io_data; 1456 1457 wait->ret = ret; 1458 complete(&wait->done); 1459 return RQ_END_IO_NONE; 1460 } 1461 1462 bool blk_rq_is_poll(struct request *rq) 1463 { 1464 if (!rq->mq_hctx) 1465 return false; 1466 if (rq->mq_hctx->type != HCTX_TYPE_POLL) 1467 return false; 1468 return true; 1469 } 1470 EXPORT_SYMBOL_GPL(blk_rq_is_poll); 1471 1472 static void blk_rq_poll_completion(struct request *rq, struct completion *wait) 1473 { 1474 do { 1475 blk_hctx_poll(rq->q, rq->mq_hctx, NULL, 0); 1476 cond_resched(); 1477 } while (!completion_done(wait)); 1478 } 1479 1480 /** 1481 * blk_execute_rq - insert a request into queue for execution 1482 * @rq: request to insert 1483 * @at_head: insert request at head or tail of queue 1484 * 1485 * Description: 1486 * Insert a fully prepared request at the back of the I/O scheduler queue 1487 * for execution and wait for completion. 1488 * Return: The blk_status_t result provided to blk_mq_end_request(). 1489 */ 1490 blk_status_t blk_execute_rq(struct request *rq, bool at_head) 1491 { 1492 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 1493 struct blk_rq_wait wait = { 1494 .done = COMPLETION_INITIALIZER_ONSTACK(wait.done), 1495 }; 1496 1497 WARN_ON(irqs_disabled()); 1498 WARN_ON(!blk_rq_is_passthrough(rq)); 1499 1500 rq->end_io_data = &wait; 1501 rq->end_io = blk_end_sync_rq; 1502 1503 blk_account_io_start(rq); 1504 blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0); 1505 blk_mq_run_hw_queue(hctx, false); 1506 1507 if (blk_rq_is_poll(rq)) 1508 blk_rq_poll_completion(rq, &wait.done); 1509 else 1510 blk_wait_io(&wait.done); 1511 1512 return wait.ret; 1513 } 1514 EXPORT_SYMBOL(blk_execute_rq); 1515 1516 static void __blk_mq_requeue_request(struct request *rq) 1517 { 1518 struct request_queue *q = rq->q; 1519 1520 blk_mq_put_driver_tag(rq); 1521 1522 trace_block_rq_requeue(rq); 1523 rq_qos_requeue(q, rq); 1524 1525 if (blk_mq_request_started(rq)) { 1526 WRITE_ONCE(rq->state, MQ_RQ_IDLE); 1527 rq->rq_flags &= ~RQF_TIMED_OUT; 1528 } 1529 } 1530 1531 void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list) 1532 { 1533 struct request_queue *q = rq->q; 1534 unsigned long flags; 1535 1536 __blk_mq_requeue_request(rq); 1537 1538 /* this request will be re-inserted to io scheduler queue */ 1539 blk_mq_sched_requeue_request(rq); 1540 1541 spin_lock_irqsave(&q->requeue_lock, flags); 1542 list_add_tail(&rq->queuelist, &q->requeue_list); 1543 spin_unlock_irqrestore(&q->requeue_lock, flags); 1544 1545 if (kick_requeue_list) 1546 blk_mq_kick_requeue_list(q); 1547 } 1548 EXPORT_SYMBOL(blk_mq_requeue_request); 1549 1550 static void blk_mq_requeue_work(struct work_struct *work) 1551 { 1552 struct request_queue *q = 1553 container_of(work, struct request_queue, requeue_work.work); 1554 LIST_HEAD(rq_list); 1555 LIST_HEAD(flush_list); 1556 struct request *rq; 1557 1558 spin_lock_irq(&q->requeue_lock); 1559 list_splice_init(&q->requeue_list, &rq_list); 1560 list_splice_init(&q->flush_list, &flush_list); 1561 spin_unlock_irq(&q->requeue_lock); 1562 1563 while (!list_empty(&rq_list)) { 1564 rq = list_entry(rq_list.next, struct request, queuelist); 1565 list_del_init(&rq->queuelist); 1566 /* 1567 * If RQF_DONTPREP is set, the request has been started by the 1568 * driver already and might have driver-specific data allocated 1569 * already. Insert it into the hctx dispatch list to avoid 1570 * block layer merges for the request. 1571 */ 1572 if (rq->rq_flags & RQF_DONTPREP) 1573 blk_mq_request_bypass_insert(rq, 0); 1574 else 1575 blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD); 1576 } 1577 1578 while (!list_empty(&flush_list)) { 1579 rq = list_entry(flush_list.next, struct request, queuelist); 1580 list_del_init(&rq->queuelist); 1581 blk_mq_insert_request(rq, 0); 1582 } 1583 1584 blk_mq_run_hw_queues(q, false); 1585 } 1586 1587 void blk_mq_kick_requeue_list(struct request_queue *q) 1588 { 1589 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0); 1590 } 1591 EXPORT_SYMBOL(blk_mq_kick_requeue_list); 1592 1593 void blk_mq_delay_kick_requeue_list(struct request_queue *q, 1594 unsigned long msecs) 1595 { 1596 kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 1597 msecs_to_jiffies(msecs)); 1598 } 1599 EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list); 1600 1601 static bool blk_is_flush_data_rq(struct request *rq) 1602 { 1603 return (rq->rq_flags & RQF_FLUSH_SEQ) && !is_flush_rq(rq); 1604 } 1605 1606 static bool blk_mq_rq_inflight(struct request *rq, void *priv) 1607 { 1608 /* 1609 * If we find a request that isn't idle we know the queue is busy 1610 * as it's checked in the iter. 1611 * Return false to stop the iteration. 1612 * 1613 * In case of queue quiesce, if one flush data request is completed, 1614 * don't count it as inflight given the flush sequence is suspended, 1615 * and the original flush data request is invisible to driver, just 1616 * like other pending requests because of quiesce 1617 */ 1618 if (blk_mq_request_started(rq) && !(blk_queue_quiesced(rq->q) && 1619 blk_is_flush_data_rq(rq) && 1620 blk_mq_request_completed(rq))) { 1621 bool *busy = priv; 1622 1623 *busy = true; 1624 return false; 1625 } 1626 1627 return true; 1628 } 1629 1630 bool blk_mq_queue_inflight(struct request_queue *q) 1631 { 1632 bool busy = false; 1633 1634 blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy); 1635 return busy; 1636 } 1637 EXPORT_SYMBOL_GPL(blk_mq_queue_inflight); 1638 1639 static void blk_mq_rq_timed_out(struct request *req) 1640 { 1641 req->rq_flags |= RQF_TIMED_OUT; 1642 if (req->q->mq_ops->timeout) { 1643 enum blk_eh_timer_return ret; 1644 1645 ret = req->q->mq_ops->timeout(req); 1646 if (ret == BLK_EH_DONE) 1647 return; 1648 WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER); 1649 } 1650 1651 blk_add_timer(req); 1652 } 1653 1654 struct blk_expired_data { 1655 bool has_timedout_rq; 1656 unsigned long next; 1657 unsigned long timeout_start; 1658 }; 1659 1660 static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired) 1661 { 1662 unsigned long deadline; 1663 1664 if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT) 1665 return false; 1666 if (rq->rq_flags & RQF_TIMED_OUT) 1667 return false; 1668 1669 deadline = READ_ONCE(rq->deadline); 1670 if (time_after_eq(expired->timeout_start, deadline)) 1671 return true; 1672 1673 if (expired->next == 0) 1674 expired->next = deadline; 1675 else if (time_after(expired->next, deadline)) 1676 expired->next = deadline; 1677 return false; 1678 } 1679 1680 void blk_mq_put_rq_ref(struct request *rq) 1681 { 1682 if (is_flush_rq(rq)) { 1683 if (rq->end_io(rq, 0) == RQ_END_IO_FREE) 1684 blk_mq_free_request(rq); 1685 } else if (req_ref_put_and_test(rq)) { 1686 __blk_mq_free_request(rq); 1687 } 1688 } 1689 1690 static bool blk_mq_check_expired(struct request *rq, void *priv) 1691 { 1692 struct blk_expired_data *expired = priv; 1693 1694 /* 1695 * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot 1696 * be reallocated underneath the timeout handler's processing, then 1697 * the expire check is reliable. If the request is not expired, then 1698 * it was completed and reallocated as a new request after returning 1699 * from blk_mq_check_expired(). 1700 */ 1701 if (blk_mq_req_expired(rq, expired)) { 1702 expired->has_timedout_rq = true; 1703 return false; 1704 } 1705 return true; 1706 } 1707 1708 static bool blk_mq_handle_expired(struct request *rq, void *priv) 1709 { 1710 struct blk_expired_data *expired = priv; 1711 1712 if (blk_mq_req_expired(rq, expired)) 1713 blk_mq_rq_timed_out(rq); 1714 return true; 1715 } 1716 1717 static void blk_mq_timeout_work(struct work_struct *work) 1718 { 1719 struct request_queue *q = 1720 container_of(work, struct request_queue, timeout_work); 1721 struct blk_expired_data expired = { 1722 .timeout_start = jiffies, 1723 }; 1724 struct blk_mq_hw_ctx *hctx; 1725 unsigned long i; 1726 1727 /* A deadlock might occur if a request is stuck requiring a 1728 * timeout at the same time a queue freeze is waiting 1729 * completion, since the timeout code would not be able to 1730 * acquire the queue reference here. 1731 * 1732 * That's why we don't use blk_queue_enter here; instead, we use 1733 * percpu_ref_tryget directly, because we need to be able to 1734 * obtain a reference even in the short window between the queue 1735 * starting to freeze, by dropping the first reference in 1736 * blk_freeze_queue_start, and the moment the last request is 1737 * consumed, marked by the instant q_usage_counter reaches 1738 * zero. 1739 */ 1740 if (!percpu_ref_tryget(&q->q_usage_counter)) 1741 return; 1742 1743 /* check if there is any timed-out request */ 1744 blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired); 1745 if (expired.has_timedout_rq) { 1746 /* 1747 * Before walking tags, we must ensure any submit started 1748 * before the current time has finished. Since the submit 1749 * uses srcu or rcu, wait for a synchronization point to 1750 * ensure all running submits have finished 1751 */ 1752 blk_mq_wait_quiesce_done(q->tag_set); 1753 1754 expired.next = 0; 1755 blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired); 1756 } 1757 1758 if (expired.next != 0) { 1759 mod_timer(&q->timeout, expired.next); 1760 } else { 1761 /* 1762 * Request timeouts are handled as a forward rolling timer. If 1763 * we end up here it means that no requests are pending and 1764 * also that no request has been pending for a while. Mark 1765 * each hctx as idle. 1766 */ 1767 queue_for_each_hw_ctx(q, hctx, i) { 1768 /* the hctx may be unmapped, so check it here */ 1769 if (blk_mq_hw_queue_mapped(hctx)) 1770 blk_mq_tag_idle(hctx); 1771 } 1772 } 1773 blk_queue_exit(q); 1774 } 1775 1776 struct flush_busy_ctx_data { 1777 struct blk_mq_hw_ctx *hctx; 1778 struct list_head *list; 1779 }; 1780 1781 static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data) 1782 { 1783 struct flush_busy_ctx_data *flush_data = data; 1784 struct blk_mq_hw_ctx *hctx = flush_data->hctx; 1785 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; 1786 enum hctx_type type = hctx->type; 1787 1788 spin_lock(&ctx->lock); 1789 list_splice_tail_init(&ctx->rq_lists[type], flush_data->list); 1790 sbitmap_clear_bit(sb, bitnr); 1791 spin_unlock(&ctx->lock); 1792 return true; 1793 } 1794 1795 /* 1796 * Process software queues that have been marked busy, splicing them 1797 * to the for-dispatch 1798 */ 1799 void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) 1800 { 1801 struct flush_busy_ctx_data data = { 1802 .hctx = hctx, 1803 .list = list, 1804 }; 1805 1806 sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data); 1807 } 1808 1809 struct dispatch_rq_data { 1810 struct blk_mq_hw_ctx *hctx; 1811 struct request *rq; 1812 }; 1813 1814 static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr, 1815 void *data) 1816 { 1817 struct dispatch_rq_data *dispatch_data = data; 1818 struct blk_mq_hw_ctx *hctx = dispatch_data->hctx; 1819 struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; 1820 enum hctx_type type = hctx->type; 1821 1822 spin_lock(&ctx->lock); 1823 if (!list_empty(&ctx->rq_lists[type])) { 1824 dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next); 1825 list_del_init(&dispatch_data->rq->queuelist); 1826 if (list_empty(&ctx->rq_lists[type])) 1827 sbitmap_clear_bit(sb, bitnr); 1828 } 1829 spin_unlock(&ctx->lock); 1830 1831 return !dispatch_data->rq; 1832 } 1833 1834 struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx, 1835 struct blk_mq_ctx *start) 1836 { 1837 unsigned off = start ? start->index_hw[hctx->type] : 0; 1838 struct dispatch_rq_data data = { 1839 .hctx = hctx, 1840 .rq = NULL, 1841 }; 1842 1843 __sbitmap_for_each_set(&hctx->ctx_map, off, 1844 dispatch_rq_from_ctx, &data); 1845 1846 return data.rq; 1847 } 1848 1849 bool __blk_mq_alloc_driver_tag(struct request *rq) 1850 { 1851 struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags; 1852 unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags; 1853 int tag; 1854 1855 blk_mq_tag_busy(rq->mq_hctx); 1856 1857 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) { 1858 bt = &rq->mq_hctx->tags->breserved_tags; 1859 tag_offset = 0; 1860 } else { 1861 if (!hctx_may_queue(rq->mq_hctx, bt)) 1862 return false; 1863 } 1864 1865 tag = __sbitmap_queue_get(bt); 1866 if (tag == BLK_MQ_NO_TAG) 1867 return false; 1868 1869 rq->tag = tag + tag_offset; 1870 blk_mq_inc_active_requests(rq->mq_hctx); 1871 return true; 1872 } 1873 1874 static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, 1875 int flags, void *key) 1876 { 1877 struct blk_mq_hw_ctx *hctx; 1878 1879 hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait); 1880 1881 spin_lock(&hctx->dispatch_wait_lock); 1882 if (!list_empty(&wait->entry)) { 1883 struct sbitmap_queue *sbq; 1884 1885 list_del_init(&wait->entry); 1886 sbq = &hctx->tags->bitmap_tags; 1887 atomic_dec(&sbq->ws_active); 1888 } 1889 spin_unlock(&hctx->dispatch_wait_lock); 1890 1891 blk_mq_run_hw_queue(hctx, true); 1892 return 1; 1893 } 1894 1895 /* 1896 * Mark us waiting for a tag. For shared tags, this involves hooking us into 1897 * the tag wakeups. For non-shared tags, we can simply mark us needing a 1898 * restart. For both cases, take care to check the condition again after 1899 * marking us as waiting. 1900 */ 1901 static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, 1902 struct request *rq) 1903 { 1904 struct sbitmap_queue *sbq; 1905 struct wait_queue_head *wq; 1906 wait_queue_entry_t *wait; 1907 bool ret; 1908 1909 if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) && 1910 !(blk_mq_is_shared_tags(hctx->flags))) { 1911 blk_mq_sched_mark_restart_hctx(hctx); 1912 1913 /* 1914 * It's possible that a tag was freed in the window between the 1915 * allocation failure and adding the hardware queue to the wait 1916 * queue. 1917 * 1918 * Don't clear RESTART here, someone else could have set it. 1919 * At most this will cost an extra queue run. 1920 */ 1921 return blk_mq_get_driver_tag(rq); 1922 } 1923 1924 wait = &hctx->dispatch_wait; 1925 if (!list_empty_careful(&wait->entry)) 1926 return false; 1927 1928 if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) 1929 sbq = &hctx->tags->breserved_tags; 1930 else 1931 sbq = &hctx->tags->bitmap_tags; 1932 wq = &bt_wait_ptr(sbq, hctx)->wait; 1933 1934 spin_lock_irq(&wq->lock); 1935 spin_lock(&hctx->dispatch_wait_lock); 1936 if (!list_empty(&wait->entry)) { 1937 spin_unlock(&hctx->dispatch_wait_lock); 1938 spin_unlock_irq(&wq->lock); 1939 return false; 1940 } 1941 1942 atomic_inc(&sbq->ws_active); 1943 wait->flags &= ~WQ_FLAG_EXCLUSIVE; 1944 __add_wait_queue(wq, wait); 1945 1946 /* 1947 * Add one explicit barrier since blk_mq_get_driver_tag() may 1948 * not imply barrier in case of failure. 1949 * 1950 * Order adding us to wait queue and allocating driver tag. 1951 * 1952 * The pair is the one implied in sbitmap_queue_wake_up() which 1953 * orders clearing sbitmap tag bits and waitqueue_active() in 1954 * __sbitmap_queue_wake_up(), since waitqueue_active() is lockless 1955 * 1956 * Otherwise, re-order of adding wait queue and getting driver tag 1957 * may cause __sbitmap_queue_wake_up() to wake up nothing because 1958 * the waitqueue_active() may not observe us in wait queue. 1959 */ 1960 smp_mb(); 1961 1962 /* 1963 * It's possible that a tag was freed in the window between the 1964 * allocation failure and adding the hardware queue to the wait 1965 * queue. 1966 */ 1967 ret = blk_mq_get_driver_tag(rq); 1968 if (!ret) { 1969 spin_unlock(&hctx->dispatch_wait_lock); 1970 spin_unlock_irq(&wq->lock); 1971 return false; 1972 } 1973 1974 /* 1975 * We got a tag, remove ourselves from the wait queue to ensure 1976 * someone else gets the wakeup. 1977 */ 1978 list_del_init(&wait->entry); 1979 atomic_dec(&sbq->ws_active); 1980 spin_unlock(&hctx->dispatch_wait_lock); 1981 spin_unlock_irq(&wq->lock); 1982 1983 return true; 1984 } 1985 1986 #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8 1987 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4 1988 /* 1989 * Update dispatch busy with the Exponential Weighted Moving Average(EWMA): 1990 * - EWMA is one simple way to compute running average value 1991 * - weight(7/8 and 1/8) is applied so that it can decrease exponentially 1992 * - take 4 as factor for avoiding to get too small(0) result, and this 1993 * factor doesn't matter because EWMA decreases exponentially 1994 */ 1995 static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy) 1996 { 1997 unsigned int ewma; 1998 1999 ewma = hctx->dispatch_busy; 2000 2001 if (!ewma && !busy) 2002 return; 2003 2004 ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1; 2005 if (busy) 2006 ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR; 2007 ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT; 2008 2009 hctx->dispatch_busy = ewma; 2010 } 2011 2012 #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */ 2013 2014 static void blk_mq_handle_dev_resource(struct request *rq, 2015 struct list_head *list) 2016 { 2017 list_add(&rq->queuelist, list); 2018 __blk_mq_requeue_request(rq); 2019 } 2020 2021 enum prep_dispatch { 2022 PREP_DISPATCH_OK, 2023 PREP_DISPATCH_NO_TAG, 2024 PREP_DISPATCH_NO_BUDGET, 2025 }; 2026 2027 static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq, 2028 bool need_budget) 2029 { 2030 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 2031 int budget_token = -1; 2032 2033 if (need_budget) { 2034 budget_token = blk_mq_get_dispatch_budget(rq->q); 2035 if (budget_token < 0) { 2036 blk_mq_put_driver_tag(rq); 2037 return PREP_DISPATCH_NO_BUDGET; 2038 } 2039 blk_mq_set_rq_budget_token(rq, budget_token); 2040 } 2041 2042 if (!blk_mq_get_driver_tag(rq)) { 2043 /* 2044 * The initial allocation attempt failed, so we need to 2045 * rerun the hardware queue when a tag is freed. The 2046 * waitqueue takes care of that. If the queue is run 2047 * before we add this entry back on the dispatch list, 2048 * we'll re-run it below. 2049 */ 2050 if (!blk_mq_mark_tag_wait(hctx, rq)) { 2051 /* 2052 * All budgets not got from this function will be put 2053 * together during handling partial dispatch 2054 */ 2055 if (need_budget) 2056 blk_mq_put_dispatch_budget(rq->q, budget_token); 2057 return PREP_DISPATCH_NO_TAG; 2058 } 2059 } 2060 2061 return PREP_DISPATCH_OK; 2062 } 2063 2064 /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */ 2065 static void blk_mq_release_budgets(struct request_queue *q, 2066 struct list_head *list) 2067 { 2068 struct request *rq; 2069 2070 list_for_each_entry(rq, list, queuelist) { 2071 int budget_token = blk_mq_get_rq_budget_token(rq); 2072 2073 if (budget_token >= 0) 2074 blk_mq_put_dispatch_budget(q, budget_token); 2075 } 2076 } 2077 2078 /* 2079 * blk_mq_commit_rqs will notify driver using bd->last that there is no 2080 * more requests. (See comment in struct blk_mq_ops for commit_rqs for 2081 * details) 2082 * Attention, we should explicitly call this in unusual cases: 2083 * 1) did not queue everything initially scheduled to queue 2084 * 2) the last attempt to queue a request failed 2085 */ 2086 static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued, 2087 bool from_schedule) 2088 { 2089 if (hctx->queue->mq_ops->commit_rqs && queued) { 2090 trace_block_unplug(hctx->queue, queued, !from_schedule); 2091 hctx->queue->mq_ops->commit_rqs(hctx); 2092 } 2093 } 2094 2095 /* 2096 * Returns true if we did some work AND can potentially do more. 2097 */ 2098 bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, 2099 bool get_budget) 2100 { 2101 enum prep_dispatch prep; 2102 struct request_queue *q = hctx->queue; 2103 struct request *rq; 2104 int queued; 2105 blk_status_t ret = BLK_STS_OK; 2106 bool needs_resource = false; 2107 2108 if (list_empty(list)) 2109 return false; 2110 2111 /* 2112 * Now process all the entries, sending them to the driver. 2113 */ 2114 queued = 0; 2115 do { 2116 struct blk_mq_queue_data bd; 2117 2118 rq = list_first_entry(list, struct request, queuelist); 2119 2120 WARN_ON_ONCE(hctx != rq->mq_hctx); 2121 prep = blk_mq_prep_dispatch_rq(rq, get_budget); 2122 if (prep != PREP_DISPATCH_OK) 2123 break; 2124 2125 list_del_init(&rq->queuelist); 2126 2127 bd.rq = rq; 2128 bd.last = list_empty(list); 2129 2130 ret = q->mq_ops->queue_rq(hctx, &bd); 2131 switch (ret) { 2132 case BLK_STS_OK: 2133 queued++; 2134 break; 2135 case BLK_STS_RESOURCE: 2136 needs_resource = true; 2137 fallthrough; 2138 case BLK_STS_DEV_RESOURCE: 2139 blk_mq_handle_dev_resource(rq, list); 2140 goto out; 2141 default: 2142 blk_mq_end_request(rq, ret); 2143 } 2144 } while (!list_empty(list)); 2145 out: 2146 /* If we didn't flush the entire list, we could have told the driver 2147 * there was more coming, but that turned out to be a lie. 2148 */ 2149 if (!list_empty(list) || ret != BLK_STS_OK) 2150 blk_mq_commit_rqs(hctx, queued, false); 2151 2152 /* 2153 * Any items that need requeuing? Stuff them into hctx->dispatch, 2154 * that is where we will continue on next queue run. 2155 */ 2156 if (!list_empty(list)) { 2157 bool needs_restart; 2158 /* For non-shared tags, the RESTART check will suffice */ 2159 bool no_tag = prep == PREP_DISPATCH_NO_TAG && 2160 ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) || 2161 blk_mq_is_shared_tags(hctx->flags)); 2162 2163 /* 2164 * If the caller allocated budgets, free the budgets of the 2165 * requests that have not yet been passed to the block driver. 2166 */ 2167 if (!get_budget) 2168 blk_mq_release_budgets(q, list); 2169 2170 spin_lock(&hctx->lock); 2171 list_splice_tail_init(list, &hctx->dispatch); 2172 spin_unlock(&hctx->lock); 2173 2174 /* 2175 * Order adding requests to hctx->dispatch and checking 2176 * SCHED_RESTART flag. The pair of this smp_mb() is the one 2177 * in blk_mq_sched_restart(). Avoid restart code path to 2178 * miss the new added requests to hctx->dispatch, meantime 2179 * SCHED_RESTART is observed here. 2180 */ 2181 smp_mb(); 2182 2183 /* 2184 * If SCHED_RESTART was set by the caller of this function and 2185 * it is no longer set that means that it was cleared by another 2186 * thread and hence that a queue rerun is needed. 2187 * 2188 * If 'no_tag' is set, that means that we failed getting 2189 * a driver tag with an I/O scheduler attached. If our dispatch 2190 * waitqueue is no longer active, ensure that we run the queue 2191 * AFTER adding our entries back to the list. 2192 * 2193 * If no I/O scheduler has been configured it is possible that 2194 * the hardware queue got stopped and restarted before requests 2195 * were pushed back onto the dispatch list. Rerun the queue to 2196 * avoid starvation. Notes: 2197 * - blk_mq_run_hw_queue() checks whether or not a queue has 2198 * been stopped before rerunning a queue. 2199 * - Some but not all block drivers stop a queue before 2200 * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq 2201 * and dm-rq. 2202 * 2203 * If driver returns BLK_STS_RESOURCE and SCHED_RESTART 2204 * bit is set, run queue after a delay to avoid IO stalls 2205 * that could otherwise occur if the queue is idle. We'll do 2206 * similar if we couldn't get budget or couldn't lock a zone 2207 * and SCHED_RESTART is set. 2208 */ 2209 needs_restart = blk_mq_sched_needs_restart(hctx); 2210 if (prep == PREP_DISPATCH_NO_BUDGET) 2211 needs_resource = true; 2212 if (!needs_restart || 2213 (no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) 2214 blk_mq_run_hw_queue(hctx, true); 2215 else if (needs_resource) 2216 blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY); 2217 2218 blk_mq_update_dispatch_busy(hctx, true); 2219 return false; 2220 } 2221 2222 blk_mq_update_dispatch_busy(hctx, false); 2223 return true; 2224 } 2225 2226 static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx) 2227 { 2228 int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask); 2229 2230 if (cpu >= nr_cpu_ids) 2231 cpu = cpumask_first(hctx->cpumask); 2232 return cpu; 2233 } 2234 2235 /* 2236 * ->next_cpu is always calculated from hctx->cpumask, so simply use 2237 * it for speeding up the check 2238 */ 2239 static bool blk_mq_hctx_empty_cpumask(struct blk_mq_hw_ctx *hctx) 2240 { 2241 return hctx->next_cpu >= nr_cpu_ids; 2242 } 2243 2244 /* 2245 * It'd be great if the workqueue API had a way to pass 2246 * in a mask and had some smarts for more clever placement. 2247 * For now we just round-robin here, switching for every 2248 * BLK_MQ_CPU_WORK_BATCH queued items. 2249 */ 2250 static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) 2251 { 2252 bool tried = false; 2253 int next_cpu = hctx->next_cpu; 2254 2255 /* Switch to unbound if no allowable CPUs in this hctx */ 2256 if (hctx->queue->nr_hw_queues == 1 || blk_mq_hctx_empty_cpumask(hctx)) 2257 return WORK_CPU_UNBOUND; 2258 2259 if (--hctx->next_cpu_batch <= 0) { 2260 select_cpu: 2261 next_cpu = cpumask_next_and(next_cpu, hctx->cpumask, 2262 cpu_online_mask); 2263 if (next_cpu >= nr_cpu_ids) 2264 next_cpu = blk_mq_first_mapped_cpu(hctx); 2265 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; 2266 } 2267 2268 /* 2269 * Do unbound schedule if we can't find a online CPU for this hctx, 2270 * and it should only happen in the path of handling CPU DEAD. 2271 */ 2272 if (!cpu_online(next_cpu)) { 2273 if (!tried) { 2274 tried = true; 2275 goto select_cpu; 2276 } 2277 2278 /* 2279 * Make sure to re-select CPU next time once after CPUs 2280 * in hctx->cpumask become online again. 2281 */ 2282 hctx->next_cpu = next_cpu; 2283 hctx->next_cpu_batch = 1; 2284 return WORK_CPU_UNBOUND; 2285 } 2286 2287 hctx->next_cpu = next_cpu; 2288 return next_cpu; 2289 } 2290 2291 /** 2292 * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously. 2293 * @hctx: Pointer to the hardware queue to run. 2294 * @msecs: Milliseconds of delay to wait before running the queue. 2295 * 2296 * Run a hardware queue asynchronously with a delay of @msecs. 2297 */ 2298 void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) 2299 { 2300 if (unlikely(blk_mq_hctx_stopped(hctx))) 2301 return; 2302 kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, 2303 msecs_to_jiffies(msecs)); 2304 } 2305 EXPORT_SYMBOL(blk_mq_delay_run_hw_queue); 2306 2307 static inline bool blk_mq_hw_queue_need_run(struct blk_mq_hw_ctx *hctx) 2308 { 2309 bool need_run; 2310 2311 /* 2312 * When queue is quiesced, we may be switching io scheduler, or 2313 * updating nr_hw_queues, or other things, and we can't run queue 2314 * any more, even blk_mq_hctx_has_pending() can't be called safely. 2315 * 2316 * And queue will be rerun in blk_mq_unquiesce_queue() if it is 2317 * quiesced. 2318 */ 2319 __blk_mq_run_dispatch_ops(hctx->queue, false, 2320 need_run = !blk_queue_quiesced(hctx->queue) && 2321 blk_mq_hctx_has_pending(hctx)); 2322 return need_run; 2323 } 2324 2325 /** 2326 * blk_mq_run_hw_queue - Start to run a hardware queue. 2327 * @hctx: Pointer to the hardware queue to run. 2328 * @async: If we want to run the queue asynchronously. 2329 * 2330 * Check if the request queue is not in a quiesced state and if there are 2331 * pending requests to be sent. If this is true, run the queue to send requests 2332 * to hardware. 2333 */ 2334 void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) 2335 { 2336 bool need_run; 2337 2338 /* 2339 * We can't run the queue inline with interrupts disabled. 2340 */ 2341 WARN_ON_ONCE(!async && in_interrupt()); 2342 2343 might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING); 2344 2345 need_run = blk_mq_hw_queue_need_run(hctx); 2346 if (!need_run) { 2347 unsigned long flags; 2348 2349 /* 2350 * Synchronize with blk_mq_unquiesce_queue(), because we check 2351 * if hw queue is quiesced locklessly above, we need the use 2352 * ->queue_lock to make sure we see the up-to-date status to 2353 * not miss rerunning the hw queue. 2354 */ 2355 spin_lock_irqsave(&hctx->queue->queue_lock, flags); 2356 need_run = blk_mq_hw_queue_need_run(hctx); 2357 spin_unlock_irqrestore(&hctx->queue->queue_lock, flags); 2358 2359 if (!need_run) 2360 return; 2361 } 2362 2363 if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) { 2364 blk_mq_delay_run_hw_queue(hctx, 0); 2365 return; 2366 } 2367 2368 blk_mq_run_dispatch_ops(hctx->queue, 2369 blk_mq_sched_dispatch_requests(hctx)); 2370 } 2371 EXPORT_SYMBOL(blk_mq_run_hw_queue); 2372 2373 /* 2374 * Return prefered queue to dispatch from (if any) for non-mq aware IO 2375 * scheduler. 2376 */ 2377 static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q) 2378 { 2379 struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); 2380 /* 2381 * If the IO scheduler does not respect hardware queues when 2382 * dispatching, we just don't bother with multiple HW queues and 2383 * dispatch from hctx for the current CPU since running multiple queues 2384 * just causes lock contention inside the scheduler and pointless cache 2385 * bouncing. 2386 */ 2387 struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT]; 2388 2389 if (!blk_mq_hctx_stopped(hctx)) 2390 return hctx; 2391 return NULL; 2392 } 2393 2394 /** 2395 * blk_mq_run_hw_queues - Run all hardware queues in a request queue. 2396 * @q: Pointer to the request queue to run. 2397 * @async: If we want to run the queue asynchronously. 2398 */ 2399 void blk_mq_run_hw_queues(struct request_queue *q, bool async) 2400 { 2401 struct blk_mq_hw_ctx *hctx, *sq_hctx; 2402 unsigned long i; 2403 2404 sq_hctx = NULL; 2405 if (blk_queue_sq_sched(q)) 2406 sq_hctx = blk_mq_get_sq_hctx(q); 2407 queue_for_each_hw_ctx(q, hctx, i) { 2408 if (blk_mq_hctx_stopped(hctx)) 2409 continue; 2410 /* 2411 * Dispatch from this hctx either if there's no hctx preferred 2412 * by IO scheduler or if it has requests that bypass the 2413 * scheduler. 2414 */ 2415 if (!sq_hctx || sq_hctx == hctx || 2416 !list_empty_careful(&hctx->dispatch)) 2417 blk_mq_run_hw_queue(hctx, async); 2418 } 2419 } 2420 EXPORT_SYMBOL(blk_mq_run_hw_queues); 2421 2422 /** 2423 * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously. 2424 * @q: Pointer to the request queue to run. 2425 * @msecs: Milliseconds of delay to wait before running the queues. 2426 */ 2427 void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs) 2428 { 2429 struct blk_mq_hw_ctx *hctx, *sq_hctx; 2430 unsigned long i; 2431 2432 sq_hctx = NULL; 2433 if (blk_queue_sq_sched(q)) 2434 sq_hctx = blk_mq_get_sq_hctx(q); 2435 queue_for_each_hw_ctx(q, hctx, i) { 2436 if (blk_mq_hctx_stopped(hctx)) 2437 continue; 2438 /* 2439 * If there is already a run_work pending, leave the 2440 * pending delay untouched. Otherwise, a hctx can stall 2441 * if another hctx is re-delaying the other's work 2442 * before the work executes. 2443 */ 2444 if (delayed_work_pending(&hctx->run_work)) 2445 continue; 2446 /* 2447 * Dispatch from this hctx either if there's no hctx preferred 2448 * by IO scheduler or if it has requests that bypass the 2449 * scheduler. 2450 */ 2451 if (!sq_hctx || sq_hctx == hctx || 2452 !list_empty_careful(&hctx->dispatch)) 2453 blk_mq_delay_run_hw_queue(hctx, msecs); 2454 } 2455 } 2456 EXPORT_SYMBOL(blk_mq_delay_run_hw_queues); 2457 2458 /* 2459 * This function is often used for pausing .queue_rq() by driver when 2460 * there isn't enough resource or some conditions aren't satisfied, and 2461 * BLK_STS_RESOURCE is usually returned. 2462 * 2463 * We do not guarantee that dispatch can be drained or blocked 2464 * after blk_mq_stop_hw_queue() returns. Please use 2465 * blk_mq_quiesce_queue() for that requirement. 2466 */ 2467 void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) 2468 { 2469 cancel_delayed_work(&hctx->run_work); 2470 2471 set_bit(BLK_MQ_S_STOPPED, &hctx->state); 2472 } 2473 EXPORT_SYMBOL(blk_mq_stop_hw_queue); 2474 2475 /* 2476 * This function is often used for pausing .queue_rq() by driver when 2477 * there isn't enough resource or some conditions aren't satisfied, and 2478 * BLK_STS_RESOURCE is usually returned. 2479 * 2480 * We do not guarantee that dispatch can be drained or blocked 2481 * after blk_mq_stop_hw_queues() returns. Please use 2482 * blk_mq_quiesce_queue() for that requirement. 2483 */ 2484 void blk_mq_stop_hw_queues(struct request_queue *q) 2485 { 2486 struct blk_mq_hw_ctx *hctx; 2487 unsigned long i; 2488 2489 queue_for_each_hw_ctx(q, hctx, i) 2490 blk_mq_stop_hw_queue(hctx); 2491 } 2492 EXPORT_SYMBOL(blk_mq_stop_hw_queues); 2493 2494 void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) 2495 { 2496 clear_bit(BLK_MQ_S_STOPPED, &hctx->state); 2497 2498 blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING); 2499 } 2500 EXPORT_SYMBOL(blk_mq_start_hw_queue); 2501 2502 void blk_mq_start_hw_queues(struct request_queue *q) 2503 { 2504 struct blk_mq_hw_ctx *hctx; 2505 unsigned long i; 2506 2507 queue_for_each_hw_ctx(q, hctx, i) 2508 blk_mq_start_hw_queue(hctx); 2509 } 2510 EXPORT_SYMBOL(blk_mq_start_hw_queues); 2511 2512 void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) 2513 { 2514 if (!blk_mq_hctx_stopped(hctx)) 2515 return; 2516 2517 clear_bit(BLK_MQ_S_STOPPED, &hctx->state); 2518 /* 2519 * Pairs with the smp_mb() in blk_mq_hctx_stopped() to order the 2520 * clearing of BLK_MQ_S_STOPPED above and the checking of dispatch 2521 * list in the subsequent routine. 2522 */ 2523 smp_mb__after_atomic(); 2524 blk_mq_run_hw_queue(hctx, async); 2525 } 2526 EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue); 2527 2528 void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) 2529 { 2530 struct blk_mq_hw_ctx *hctx; 2531 unsigned long i; 2532 2533 queue_for_each_hw_ctx(q, hctx, i) 2534 blk_mq_start_stopped_hw_queue(hctx, async || 2535 (hctx->flags & BLK_MQ_F_BLOCKING)); 2536 } 2537 EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); 2538 2539 static void blk_mq_run_work_fn(struct work_struct *work) 2540 { 2541 struct blk_mq_hw_ctx *hctx = 2542 container_of(work, struct blk_mq_hw_ctx, run_work.work); 2543 2544 blk_mq_run_dispatch_ops(hctx->queue, 2545 blk_mq_sched_dispatch_requests(hctx)); 2546 } 2547 2548 /** 2549 * blk_mq_request_bypass_insert - Insert a request at dispatch list. 2550 * @rq: Pointer to request to be inserted. 2551 * @flags: BLK_MQ_INSERT_* 2552 * 2553 * Should only be used carefully, when the caller knows we want to 2554 * bypass a potential IO scheduler on the target device. 2555 */ 2556 static void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags) 2557 { 2558 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 2559 2560 spin_lock(&hctx->lock); 2561 if (flags & BLK_MQ_INSERT_AT_HEAD) 2562 list_add(&rq->queuelist, &hctx->dispatch); 2563 else 2564 list_add_tail(&rq->queuelist, &hctx->dispatch); 2565 spin_unlock(&hctx->lock); 2566 } 2567 2568 static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, 2569 struct blk_mq_ctx *ctx, struct list_head *list, 2570 bool run_queue_async) 2571 { 2572 struct request *rq; 2573 enum hctx_type type = hctx->type; 2574 2575 /* 2576 * Try to issue requests directly if the hw queue isn't busy to save an 2577 * extra enqueue & dequeue to the sw queue. 2578 */ 2579 if (!hctx->dispatch_busy && !run_queue_async) { 2580 blk_mq_run_dispatch_ops(hctx->queue, 2581 blk_mq_try_issue_list_directly(hctx, list)); 2582 if (list_empty(list)) 2583 goto out; 2584 } 2585 2586 /* 2587 * preemption doesn't flush plug list, so it's possible ctx->cpu is 2588 * offline now 2589 */ 2590 list_for_each_entry(rq, list, queuelist) { 2591 BUG_ON(rq->mq_ctx != ctx); 2592 trace_block_rq_insert(rq); 2593 if (rq->cmd_flags & REQ_NOWAIT) 2594 run_queue_async = true; 2595 } 2596 2597 spin_lock(&ctx->lock); 2598 list_splice_tail_init(list, &ctx->rq_lists[type]); 2599 blk_mq_hctx_mark_pending(hctx, ctx); 2600 spin_unlock(&ctx->lock); 2601 out: 2602 blk_mq_run_hw_queue(hctx, run_queue_async); 2603 } 2604 2605 static void blk_mq_insert_request(struct request *rq, blk_insert_t flags) 2606 { 2607 struct request_queue *q = rq->q; 2608 struct blk_mq_ctx *ctx = rq->mq_ctx; 2609 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 2610 2611 if (blk_rq_is_passthrough(rq)) { 2612 /* 2613 * Passthrough request have to be added to hctx->dispatch 2614 * directly. The device may be in a situation where it can't 2615 * handle FS request, and always returns BLK_STS_RESOURCE for 2616 * them, which gets them added to hctx->dispatch. 2617 * 2618 * If a passthrough request is required to unblock the queues, 2619 * and it is added to the scheduler queue, there is no chance to 2620 * dispatch it given we prioritize requests in hctx->dispatch. 2621 */ 2622 blk_mq_request_bypass_insert(rq, flags); 2623 } else if (req_op(rq) == REQ_OP_FLUSH) { 2624 /* 2625 * Firstly normal IO request is inserted to scheduler queue or 2626 * sw queue, meantime we add flush request to dispatch queue( 2627 * hctx->dispatch) directly and there is at most one in-flight 2628 * flush request for each hw queue, so it doesn't matter to add 2629 * flush request to tail or front of the dispatch queue. 2630 * 2631 * Secondly in case of NCQ, flush request belongs to non-NCQ 2632 * command, and queueing it will fail when there is any 2633 * in-flight normal IO request(NCQ command). When adding flush 2634 * rq to the front of hctx->dispatch, it is easier to introduce 2635 * extra time to flush rq's latency because of S_SCHED_RESTART 2636 * compared with adding to the tail of dispatch queue, then 2637 * chance of flush merge is increased, and less flush requests 2638 * will be issued to controller. It is observed that ~10% time 2639 * is saved in blktests block/004 on disk attached to AHCI/NCQ 2640 * drive when adding flush rq to the front of hctx->dispatch. 2641 * 2642 * Simply queue flush rq to the front of hctx->dispatch so that 2643 * intensive flush workloads can benefit in case of NCQ HW. 2644 */ 2645 blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD); 2646 } else if (q->elevator) { 2647 LIST_HEAD(list); 2648 2649 WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG); 2650 2651 list_add(&rq->queuelist, &list); 2652 q->elevator->type->ops.insert_requests(hctx, &list, flags); 2653 } else { 2654 trace_block_rq_insert(rq); 2655 2656 spin_lock(&ctx->lock); 2657 if (flags & BLK_MQ_INSERT_AT_HEAD) 2658 list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]); 2659 else 2660 list_add_tail(&rq->queuelist, 2661 &ctx->rq_lists[hctx->type]); 2662 blk_mq_hctx_mark_pending(hctx, ctx); 2663 spin_unlock(&ctx->lock); 2664 } 2665 } 2666 2667 static void blk_mq_bio_to_request(struct request *rq, struct bio *bio, 2668 unsigned int nr_segs) 2669 { 2670 int err; 2671 2672 if (bio->bi_opf & REQ_RAHEAD) 2673 rq->cmd_flags |= REQ_FAILFAST_MASK; 2674 2675 rq->bio = rq->biotail = bio; 2676 rq->__sector = bio->bi_iter.bi_sector; 2677 rq->__data_len = bio->bi_iter.bi_size; 2678 rq->nr_phys_segments = nr_segs; 2679 if (bio_integrity(bio)) 2680 rq->nr_integrity_segments = blk_rq_count_integrity_sg(rq->q, 2681 bio); 2682 2683 /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */ 2684 err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO); 2685 WARN_ON_ONCE(err); 2686 2687 blk_account_io_start(rq); 2688 } 2689 2690 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, 2691 struct request *rq, bool last) 2692 { 2693 struct request_queue *q = rq->q; 2694 struct blk_mq_queue_data bd = { 2695 .rq = rq, 2696 .last = last, 2697 }; 2698 blk_status_t ret; 2699 2700 /* 2701 * For OK queue, we are done. For error, caller may kill it. 2702 * Any other error (busy), just add it to our list as we 2703 * previously would have done. 2704 */ 2705 ret = q->mq_ops->queue_rq(hctx, &bd); 2706 switch (ret) { 2707 case BLK_STS_OK: 2708 blk_mq_update_dispatch_busy(hctx, false); 2709 break; 2710 case BLK_STS_RESOURCE: 2711 case BLK_STS_DEV_RESOURCE: 2712 blk_mq_update_dispatch_busy(hctx, true); 2713 __blk_mq_requeue_request(rq); 2714 break; 2715 default: 2716 blk_mq_update_dispatch_busy(hctx, false); 2717 break; 2718 } 2719 2720 return ret; 2721 } 2722 2723 static bool blk_mq_get_budget_and_tag(struct request *rq) 2724 { 2725 int budget_token; 2726 2727 budget_token = blk_mq_get_dispatch_budget(rq->q); 2728 if (budget_token < 0) 2729 return false; 2730 blk_mq_set_rq_budget_token(rq, budget_token); 2731 if (!blk_mq_get_driver_tag(rq)) { 2732 blk_mq_put_dispatch_budget(rq->q, budget_token); 2733 return false; 2734 } 2735 return true; 2736 } 2737 2738 /** 2739 * blk_mq_try_issue_directly - Try to send a request directly to device driver. 2740 * @hctx: Pointer of the associated hardware queue. 2741 * @rq: Pointer to request to be sent. 2742 * 2743 * If the device has enough resources to accept a new request now, send the 2744 * request directly to device driver. Else, insert at hctx->dispatch queue, so 2745 * we can try send it another time in the future. Requests inserted at this 2746 * queue have higher priority. 2747 */ 2748 static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, 2749 struct request *rq) 2750 { 2751 blk_status_t ret; 2752 2753 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { 2754 blk_mq_insert_request(rq, 0); 2755 blk_mq_run_hw_queue(hctx, false); 2756 return; 2757 } 2758 2759 if ((rq->rq_flags & RQF_USE_SCHED) || !blk_mq_get_budget_and_tag(rq)) { 2760 blk_mq_insert_request(rq, 0); 2761 blk_mq_run_hw_queue(hctx, rq->cmd_flags & REQ_NOWAIT); 2762 return; 2763 } 2764 2765 ret = __blk_mq_issue_directly(hctx, rq, true); 2766 switch (ret) { 2767 case BLK_STS_OK: 2768 break; 2769 case BLK_STS_RESOURCE: 2770 case BLK_STS_DEV_RESOURCE: 2771 blk_mq_request_bypass_insert(rq, 0); 2772 blk_mq_run_hw_queue(hctx, false); 2773 break; 2774 default: 2775 blk_mq_end_request(rq, ret); 2776 break; 2777 } 2778 } 2779 2780 static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) 2781 { 2782 struct blk_mq_hw_ctx *hctx = rq->mq_hctx; 2783 2784 if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { 2785 blk_mq_insert_request(rq, 0); 2786 blk_mq_run_hw_queue(hctx, false); 2787 return BLK_STS_OK; 2788 } 2789 2790 if (!blk_mq_get_budget_and_tag(rq)) 2791 return BLK_STS_RESOURCE; 2792 return __blk_mq_issue_directly(hctx, rq, last); 2793 } 2794 2795 static void blk_mq_issue_direct(struct rq_list *rqs) 2796 { 2797 struct blk_mq_hw_ctx *hctx = NULL; 2798 struct request *rq; 2799 int queued = 0; 2800 blk_status_t ret = BLK_STS_OK; 2801 2802 while ((rq = rq_list_pop(rqs))) { 2803 bool last = rq_list_empty(rqs); 2804 2805 if (hctx != rq->mq_hctx) { 2806 if (hctx) { 2807 blk_mq_commit_rqs(hctx, queued, false); 2808 queued = 0; 2809 } 2810 hctx = rq->mq_hctx; 2811 } 2812 2813 ret = blk_mq_request_issue_directly(rq, last); 2814 switch (ret) { 2815 case BLK_STS_OK: 2816 queued++; 2817 break; 2818 case BLK_STS_RESOURCE: 2819 case BLK_STS_DEV_RESOURCE: 2820 blk_mq_request_bypass_insert(rq, 0); 2821 blk_mq_run_hw_queue(hctx, false); 2822 goto out; 2823 default: 2824 blk_mq_end_request(rq, ret); 2825 break; 2826 } 2827 } 2828 2829 out: 2830 if (ret != BLK_STS_OK) 2831 blk_mq_commit_rqs(hctx, queued, false); 2832 } 2833 2834 static void __blk_mq_flush_list(struct request_queue *q, struct rq_list *rqs) 2835 { 2836 if (blk_queue_quiesced(q)) 2837 return; 2838 q->mq_ops->queue_rqs(rqs); 2839 } 2840 2841 static unsigned blk_mq_extract_queue_requests(struct rq_list *rqs, 2842 struct rq_list *queue_rqs) 2843 { 2844 struct request *rq = rq_list_pop(rqs); 2845 struct request_queue *this_q = rq->q; 2846 struct request **prev = &rqs->head; 2847 struct rq_list matched_rqs = {}; 2848 struct request *last = NULL; 2849 unsigned depth = 1; 2850 2851 rq_list_add_tail(&matched_rqs, rq); 2852 while ((rq = *prev)) { 2853 if (rq->q == this_q) { 2854 /* move rq from rqs to matched_rqs */ 2855 *prev = rq->rq_next; 2856 rq_list_add_tail(&matched_rqs, rq); 2857 depth++; 2858 } else { 2859 /* leave rq in rqs */ 2860 prev = &rq->rq_next; 2861 last = rq; 2862 } 2863 } 2864 2865 rqs->tail = last; 2866 *queue_rqs = matched_rqs; 2867 return depth; 2868 } 2869 2870 static void blk_mq_dispatch_queue_requests(struct rq_list *rqs, unsigned depth) 2871 { 2872 struct request_queue *q = rq_list_peek(rqs)->q; 2873 2874 trace_block_unplug(q, depth, true); 2875 2876 /* 2877 * Peek first request and see if we have a ->queue_rqs() hook. 2878 * If we do, we can dispatch the whole list in one go. 2879 * We already know at this point that all requests belong to the 2880 * same queue, caller must ensure that's the case. 2881 */ 2882 if (q->mq_ops->queue_rqs) { 2883 blk_mq_run_dispatch_ops(q, __blk_mq_flush_list(q, rqs)); 2884 if (rq_list_empty(rqs)) 2885 return; 2886 } 2887 2888 blk_mq_run_dispatch_ops(q, blk_mq_issue_direct(rqs)); 2889 } 2890 2891 static void blk_mq_dispatch_list(struct rq_list *rqs, bool from_sched) 2892 { 2893 struct blk_mq_hw_ctx *this_hctx = NULL; 2894 struct blk_mq_ctx *this_ctx = NULL; 2895 struct rq_list requeue_list = {}; 2896 unsigned int depth = 0; 2897 bool is_passthrough = false; 2898 LIST_HEAD(list); 2899 2900 do { 2901 struct request *rq = rq_list_pop(rqs); 2902 2903 if (!this_hctx) { 2904 this_hctx = rq->mq_hctx; 2905 this_ctx = rq->mq_ctx; 2906 is_passthrough = blk_rq_is_passthrough(rq); 2907 } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx || 2908 is_passthrough != blk_rq_is_passthrough(rq)) { 2909 rq_list_add_tail(&requeue_list, rq); 2910 continue; 2911 } 2912 list_add_tail(&rq->queuelist, &list); 2913 depth++; 2914 } while (!rq_list_empty(rqs)); 2915 2916 *rqs = requeue_list; 2917 trace_block_unplug(this_hctx->queue, depth, !from_sched); 2918 2919 percpu_ref_get(&this_hctx->queue->q_usage_counter); 2920 /* passthrough requests should never be issued to the I/O scheduler */ 2921 if (is_passthrough) { 2922 spin_lock(&this_hctx->lock); 2923 list_splice_tail_init(&list, &this_hctx->dispatch); 2924 spin_unlock(&this_hctx->lock); 2925 blk_mq_run_hw_queue(this_hctx, from_sched); 2926 } else if (this_hctx->queue->elevator) { 2927 this_hctx->queue->elevator->type->ops.insert_requests(this_hctx, 2928 &list, 0); 2929 blk_mq_run_hw_queue(this_hctx, from_sched); 2930 } else { 2931 blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched); 2932 } 2933 percpu_ref_put(&this_hctx->queue->q_usage_counter); 2934 } 2935 2936 static void blk_mq_dispatch_multiple_queue_requests(struct rq_list *rqs) 2937 { 2938 do { 2939 struct rq_list queue_rqs; 2940 unsigned depth; 2941 2942 depth = blk_mq_extract_queue_requests(rqs, &queue_rqs); 2943 blk_mq_dispatch_queue_requests(&queue_rqs, depth); 2944 while (!rq_list_empty(&queue_rqs)) 2945 blk_mq_dispatch_list(&queue_rqs, false); 2946 } while (!rq_list_empty(rqs)); 2947 } 2948 2949 void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) 2950 { 2951 unsigned int depth; 2952 2953 /* 2954 * We may have been called recursively midway through handling 2955 * plug->mq_list via a schedule() in the driver's queue_rq() callback. 2956 * To avoid mq_list changing under our feet, clear rq_count early and 2957 * bail out specifically if rq_count is 0 rather than checking 2958 * whether the mq_list is empty. 2959 */ 2960 if (plug->rq_count == 0) 2961 return; 2962 depth = plug->rq_count; 2963 plug->rq_count = 0; 2964 2965 if (!plug->has_elevator && !from_schedule) { 2966 if (plug->multiple_queues) { 2967 blk_mq_dispatch_multiple_queue_requests(&plug->mq_list); 2968 return; 2969 } 2970 2971 blk_mq_dispatch_queue_requests(&plug->mq_list, depth); 2972 if (rq_list_empty(&plug->mq_list)) 2973 return; 2974 } 2975 2976 do { 2977 blk_mq_dispatch_list(&plug->mq_list, from_schedule); 2978 } while (!rq_list_empty(&plug->mq_list)); 2979 } 2980 2981 static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, 2982 struct list_head *list) 2983 { 2984 int queued = 0; 2985 blk_status_t ret = BLK_STS_OK; 2986 2987 while (!list_empty(list)) { 2988 struct request *rq = list_first_entry(list, struct request, 2989 queuelist); 2990 2991 list_del_init(&rq->queuelist); 2992 ret = blk_mq_request_issue_directly(rq, list_empty(list)); 2993 switch (ret) { 2994 case BLK_STS_OK: 2995 queued++; 2996 break; 2997 case BLK_STS_RESOURCE: 2998 case BLK_STS_DEV_RESOURCE: 2999 blk_mq_request_bypass_insert(rq, 0); 3000 if (list_empty(list)) 3001 blk_mq_run_hw_queue(hctx, false); 3002 goto out; 3003 default: 3004 blk_mq_end_request(rq, ret); 3005 break; 3006 } 3007 } 3008 3009 out: 3010 if (ret != BLK_STS_OK) 3011 blk_mq_commit_rqs(hctx, queued, false); 3012 } 3013 3014 static bool blk_mq_attempt_bio_merge(struct request_queue *q, 3015 struct bio *bio, unsigned int nr_segs) 3016 { 3017 if (!blk_queue_nomerges(q) && bio_mergeable(bio)) { 3018 if (blk_attempt_plug_merge(q, bio, nr_segs)) 3019 return true; 3020 if (blk_mq_sched_bio_merge(q, bio, nr_segs)) 3021 return true; 3022 } 3023 return false; 3024 } 3025 3026 static struct request *blk_mq_get_new_requests(struct request_queue *q, 3027 struct blk_plug *plug, 3028 struct bio *bio) 3029 { 3030 struct blk_mq_alloc_data data = { 3031 .q = q, 3032 .flags = 0, 3033 .shallow_depth = 0, 3034 .cmd_flags = bio->bi_opf, 3035 .rq_flags = 0, 3036 .nr_tags = 1, 3037 .cached_rqs = NULL, 3038 .ctx = NULL, 3039 .hctx = NULL 3040 }; 3041 struct request *rq; 3042 3043 rq_qos_throttle(q, bio); 3044 3045 if (plug) { 3046 data.nr_tags = plug->nr_ios; 3047 plug->nr_ios = 1; 3048 data.cached_rqs = &plug->cached_rqs; 3049 } 3050 3051 rq = __blk_mq_alloc_requests(&data); 3052 if (unlikely(!rq)) 3053 rq_qos_cleanup(q, bio); 3054 return rq; 3055 } 3056 3057 /* 3058 * Check if there is a suitable cached request and return it. 3059 */ 3060 static struct request *blk_mq_peek_cached_request(struct blk_plug *plug, 3061 struct request_queue *q, blk_opf_t opf) 3062 { 3063 enum hctx_type type = blk_mq_get_hctx_type(opf); 3064 struct request *rq; 3065 3066 if (!plug) 3067 return NULL; 3068 rq = rq_list_peek(&plug->cached_rqs); 3069 if (!rq || rq->q != q) 3070 return NULL; 3071 if (type != rq->mq_hctx->type && 3072 (type != HCTX_TYPE_READ || rq->mq_hctx->type != HCTX_TYPE_DEFAULT)) 3073 return NULL; 3074 if (op_is_flush(rq->cmd_flags) != op_is_flush(opf)) 3075 return NULL; 3076 return rq; 3077 } 3078 3079 static void blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug, 3080 struct bio *bio) 3081 { 3082 if (rq_list_pop(&plug->cached_rqs) != rq) 3083 WARN_ON_ONCE(1); 3084 3085 /* 3086 * If any qos ->throttle() end up blocking, we will have flushed the 3087 * plug and hence killed the cached_rq list as well. Pop this entry 3088 * before we throttle. 3089 */ 3090 rq_qos_throttle(rq->q, bio); 3091 3092 blk_mq_rq_time_init(rq, blk_time_get_ns()); 3093 rq->cmd_flags = bio->bi_opf; 3094 INIT_LIST_HEAD(&rq->queuelist); 3095 } 3096 3097 static bool bio_unaligned(const struct bio *bio, struct request_queue *q) 3098 { 3099 unsigned int bs_mask = queue_logical_block_size(q) - 1; 3100 3101 /* .bi_sector of any zero sized bio need to be initialized */ 3102 if ((bio->bi_iter.bi_size & bs_mask) || 3103 ((bio->bi_iter.bi_sector << SECTOR_SHIFT) & bs_mask)) 3104 return true; 3105 return false; 3106 } 3107 3108 /** 3109 * blk_mq_submit_bio - Create and send a request to block device. 3110 * @bio: Bio pointer. 3111 * 3112 * Builds up a request structure from @q and @bio and send to the device. The 3113 * request may not be queued directly to hardware if: 3114 * * This request can be merged with another one 3115 * * We want to place request at plug queue for possible future merging 3116 * * There is an IO scheduler active at this queue 3117 * 3118 * It will not queue the request if there is an error with the bio, or at the 3119 * request creation. 3120 */ 3121 void blk_mq_submit_bio(struct bio *bio) 3122 { 3123 struct request_queue *q = bdev_get_queue(bio->bi_bdev); 3124 struct blk_plug *plug = current->plug; 3125 const int is_sync = op_is_sync(bio->bi_opf); 3126 struct blk_mq_hw_ctx *hctx; 3127 unsigned int nr_segs; 3128 struct request *rq; 3129 blk_status_t ret; 3130 3131 /* 3132 * If the plug has a cached request for this queue, try to use it. 3133 */ 3134 rq = blk_mq_peek_cached_request(plug, q, bio->bi_opf); 3135 3136 /* 3137 * A BIO that was released from a zone write plug has already been 3138 * through the preparation in this function, already holds a reference 3139 * on the queue usage counter, and is the only write BIO in-flight for 3140 * the target zone. Go straight to preparing a request for it. 3141 */ 3142 if (bio_zone_write_plugging(bio)) { 3143 nr_segs = bio->__bi_nr_segments; 3144 if (rq) 3145 blk_queue_exit(q); 3146 goto new_request; 3147 } 3148 3149 /* 3150 * The cached request already holds a q_usage_counter reference and we 3151 * don't have to acquire a new one if we use it. 3152 */ 3153 if (!rq) { 3154 if (unlikely(bio_queue_enter(bio))) 3155 return; 3156 } 3157 3158 /* 3159 * Device reconfiguration may change logical block size or reduce the 3160 * number of poll queues, so the checks for alignment and poll support 3161 * have to be done with queue usage counter held. 3162 */ 3163 if (unlikely(bio_unaligned(bio, q))) { 3164 bio_io_error(bio); 3165 goto queue_exit; 3166 } 3167 3168 if ((bio->bi_opf & REQ_POLLED) && !blk_mq_can_poll(q)) { 3169 bio->bi_status = BLK_STS_NOTSUPP; 3170 bio_endio(bio); 3171 goto queue_exit; 3172 } 3173 3174 bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); 3175 if (!bio) 3176 goto queue_exit; 3177 3178 if (!bio_integrity_prep(bio)) 3179 goto queue_exit; 3180 3181 blk_mq_bio_issue_init(q, bio); 3182 if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) 3183 goto queue_exit; 3184 3185 if (bio_needs_zone_write_plugging(bio)) { 3186 if (blk_zone_plug_bio(bio, nr_segs)) 3187 goto queue_exit; 3188 } 3189 3190 new_request: 3191 if (rq) { 3192 blk_mq_use_cached_rq(rq, plug, bio); 3193 } else { 3194 rq = blk_mq_get_new_requests(q, plug, bio); 3195 if (unlikely(!rq)) { 3196 if (bio->bi_opf & REQ_NOWAIT) 3197 bio_wouldblock_error(bio); 3198 goto queue_exit; 3199 } 3200 } 3201 3202 trace_block_getrq(bio); 3203 3204 rq_qos_track(q, rq, bio); 3205 3206 blk_mq_bio_to_request(rq, bio, nr_segs); 3207 3208 ret = blk_crypto_rq_get_keyslot(rq); 3209 if (ret != BLK_STS_OK) { 3210 bio->bi_status = ret; 3211 bio_endio(bio); 3212 blk_mq_free_request(rq); 3213 return; 3214 } 3215 3216 if (bio_zone_write_plugging(bio)) 3217 blk_zone_write_plug_init_request(rq); 3218 3219 if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq)) 3220 return; 3221 3222 if (plug) { 3223 blk_add_rq_to_plug(plug, rq); 3224 return; 3225 } 3226 3227 hctx = rq->mq_hctx; 3228 if ((rq->rq_flags & RQF_USE_SCHED) || 3229 (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) { 3230 blk_mq_insert_request(rq, 0); 3231 blk_mq_run_hw_queue(hctx, true); 3232 } else { 3233 blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq)); 3234 } 3235 return; 3236 3237 queue_exit: 3238 /* 3239 * Don't drop the queue reference if we were trying to use a cached 3240 * request and thus didn't acquire one. 3241 */ 3242 if (!rq) 3243 blk_queue_exit(q); 3244 } 3245 3246 #ifdef CONFIG_BLK_MQ_STACKING 3247 /** 3248 * blk_insert_cloned_request - Helper for stacking drivers to submit a request 3249 * @rq: the request being queued 3250 */ 3251 blk_status_t blk_insert_cloned_request(struct request *rq) 3252 { 3253 struct request_queue *q = rq->q; 3254 unsigned int max_sectors = blk_queue_get_max_sectors(rq); 3255 unsigned int max_segments = blk_rq_get_max_segments(rq); 3256 blk_status_t ret; 3257 3258 if (blk_rq_sectors(rq) > max_sectors) { 3259 /* 3260 * SCSI device does not have a good way to return if 3261 * Write Same/Zero is actually supported. If a device rejects 3262 * a non-read/write command (discard, write same,etc.) the 3263 * low-level device driver will set the relevant queue limit to 3264 * 0 to prevent blk-lib from issuing more of the offending 3265 * operations. Commands queued prior to the queue limit being 3266 * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O 3267 * errors being propagated to upper layers. 3268 */ 3269 if (max_sectors == 0) 3270 return BLK_STS_NOTSUPP; 3271 3272 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n", 3273 __func__, blk_rq_sectors(rq), max_sectors); 3274 return BLK_STS_IOERR; 3275 } 3276 3277 /* 3278 * The queue settings related to segment counting may differ from the 3279 * original queue. 3280 */ 3281 rq->nr_phys_segments = blk_recalc_rq_segments(rq); 3282 if (rq->nr_phys_segments > max_segments) { 3283 printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n", 3284 __func__, rq->nr_phys_segments, max_segments); 3285 return BLK_STS_IOERR; 3286 } 3287 3288 /* 3289 * Integrity segment counting depends on the same queue limits 3290 * (virt_boundary_mask, seg_boundary_mask, max_segment_size) that 3291 * vary across stacked queues, so recompute against the bottom 3292 * queue just like nr_phys_segments above. 3293 */ 3294 if (blk_integrity_rq(rq) && rq->bio) { 3295 unsigned short max_int_segs = queue_max_integrity_segments(q); 3296 3297 rq->nr_integrity_segments = 3298 blk_rq_count_integrity_sg(rq->q, rq->bio); 3299 if (rq->nr_integrity_segments > max_int_segs) { 3300 printk(KERN_ERR "%s: over max integrity segments limit. (%u > %u)\n", 3301 __func__, rq->nr_integrity_segments, 3302 max_int_segs); 3303 return BLK_STS_IOERR; 3304 } 3305 } 3306 3307 if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq))) 3308 return BLK_STS_IOERR; 3309 3310 ret = blk_crypto_rq_get_keyslot(rq); 3311 if (ret != BLK_STS_OK) 3312 return ret; 3313 3314 blk_account_io_start(rq); 3315 3316 /* 3317 * Since we have a scheduler attached on the top device, 3318 * bypass a potential scheduler on the bottom device for 3319 * insert. 3320 */ 3321 blk_mq_run_dispatch_ops(q, 3322 ret = blk_mq_request_issue_directly(rq, true)); 3323 if (ret) 3324 blk_account_io_done(rq, blk_time_get_ns()); 3325 return ret; 3326 } 3327 EXPORT_SYMBOL_GPL(blk_insert_cloned_request); 3328 3329 /** 3330 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request 3331 * @rq: the clone request to be cleaned up 3332 * 3333 * Description: 3334 * Free all bios in @rq for a cloned request. 3335 */ 3336 void blk_rq_unprep_clone(struct request *rq) 3337 { 3338 struct bio *bio; 3339 3340 while ((bio = rq->bio) != NULL) { 3341 rq->bio = bio->bi_next; 3342 3343 bio_put(bio); 3344 } 3345 } 3346 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); 3347 3348 /** 3349 * blk_rq_prep_clone - Helper function to setup clone request 3350 * @rq: the request to be setup 3351 * @rq_src: original request to be cloned 3352 * @bs: bio_set that bios for clone are allocated from 3353 * @gfp_mask: memory allocation mask for bio 3354 * @bio_ctr: setup function to be called for each clone bio. 3355 * Returns %0 for success, non %0 for failure. 3356 * @data: private data to be passed to @bio_ctr 3357 * 3358 * Description: 3359 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. 3360 * Also, pages which the original bios are pointing to are not copied 3361 * and the cloned bios just point same pages. 3362 * So cloned bios must be completed before original bios, which means 3363 * the caller must complete @rq before @rq_src. 3364 */ 3365 int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 3366 struct bio_set *bs, gfp_t gfp_mask, 3367 int (*bio_ctr)(struct bio *, struct bio *, void *), 3368 void *data) 3369 { 3370 struct bio *bio_src; 3371 3372 if (!bs) 3373 bs = &fs_bio_set; 3374 3375 __rq_for_each_bio(bio_src, rq_src) { 3376 struct bio *bio = bio_alloc_clone(rq->q->disk->part0, bio_src, 3377 gfp_mask, bs); 3378 if (!bio) 3379 goto free_and_out; 3380 3381 if (bio_ctr && bio_ctr(bio, bio_src, data)) { 3382 bio_put(bio); 3383 goto free_and_out; 3384 } 3385 3386 if (rq->bio) { 3387 rq->biotail->bi_next = bio; 3388 rq->biotail = bio; 3389 } else { 3390 rq->bio = rq->biotail = bio; 3391 } 3392 } 3393 3394 /* Copy attributes of the original request to the clone request. */ 3395 rq->__sector = blk_rq_pos(rq_src); 3396 rq->__data_len = blk_rq_bytes(rq_src); 3397 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) { 3398 rq->rq_flags |= RQF_SPECIAL_PAYLOAD; 3399 rq->special_vec = rq_src->special_vec; 3400 } 3401 rq->nr_phys_segments = rq_src->nr_phys_segments; 3402 rq->nr_integrity_segments = rq_src->nr_integrity_segments; 3403 3404 if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0) 3405 goto free_and_out; 3406 3407 return 0; 3408 3409 free_and_out: 3410 blk_rq_unprep_clone(rq); 3411 3412 return -ENOMEM; 3413 } 3414 EXPORT_SYMBOL_GPL(blk_rq_prep_clone); 3415 #endif /* CONFIG_BLK_MQ_STACKING */ 3416 3417 /* 3418 * Steal bios from a request and add them to a bio list. 3419 * The request must not have been partially completed before. 3420 */ 3421 void blk_steal_bios(struct bio_list *list, struct request *rq) 3422 { 3423 if (rq->bio) { 3424 if (list->tail) 3425 list->tail->bi_next = rq->bio; 3426 else 3427 list->head = rq->bio; 3428 list->tail = rq->biotail; 3429 3430 rq->bio = NULL; 3431 rq->biotail = NULL; 3432 } 3433 3434 rq->__data_len = 0; 3435 } 3436 EXPORT_SYMBOL_GPL(blk_steal_bios); 3437 3438 static size_t order_to_size(unsigned int order) 3439 { 3440 return (size_t)PAGE_SIZE << order; 3441 } 3442 3443 /* called before freeing request pool in @tags */ 3444 static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags, 3445 struct blk_mq_tags *tags) 3446 { 3447 struct page *page; 3448 3449 /* 3450 * There is no need to clear mapping if driver tags is not initialized 3451 * or the mapping belongs to the driver tags. 3452 */ 3453 if (!drv_tags || drv_tags == tags) 3454 return; 3455 3456 list_for_each_entry(page, &tags->page_list, lru) { 3457 unsigned long start = (unsigned long)page_address(page); 3458 unsigned long end = start + order_to_size(page->private); 3459 int i; 3460 3461 for (i = 0; i < drv_tags->nr_tags; i++) { 3462 struct request *rq = drv_tags->rqs[i]; 3463 unsigned long rq_addr = (unsigned long)rq; 3464 3465 if (rq_addr >= start && rq_addr < end) { 3466 WARN_ON_ONCE(req_ref_read(rq) != 0); 3467 cmpxchg(&drv_tags->rqs[i], rq, NULL); 3468 } 3469 } 3470 } 3471 } 3472 3473 void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, 3474 unsigned int hctx_idx) 3475 { 3476 struct blk_mq_tags *drv_tags; 3477 3478 if (list_empty(&tags->page_list)) 3479 return; 3480 3481 if (blk_mq_is_shared_tags(set->flags)) 3482 drv_tags = set->shared_tags; 3483 else 3484 drv_tags = set->tags[hctx_idx]; 3485 3486 if (tags->static_rqs && set->ops->exit_request) { 3487 int i; 3488 3489 for (i = 0; i < tags->nr_tags; i++) { 3490 struct request *rq = tags->static_rqs[i]; 3491 3492 if (!rq) 3493 continue; 3494 set->ops->exit_request(set, rq, hctx_idx); 3495 tags->static_rqs[i] = NULL; 3496 } 3497 } 3498 3499 blk_mq_clear_rq_mapping(drv_tags, tags); 3500 /* 3501 * Free request pages in SRCU callback, which is called from 3502 * blk_mq_free_tags(). 3503 */ 3504 } 3505 3506 void blk_mq_free_rq_map(struct blk_mq_tag_set *set, struct blk_mq_tags *tags) 3507 { 3508 kfree(tags->rqs); 3509 tags->rqs = NULL; 3510 kfree(tags->static_rqs); 3511 tags->static_rqs = NULL; 3512 3513 blk_mq_free_tags(set, tags); 3514 } 3515 3516 static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set, 3517 unsigned int hctx_idx) 3518 { 3519 int i; 3520 3521 for (i = 0; i < set->nr_maps; i++) { 3522 unsigned int start = set->map[i].queue_offset; 3523 unsigned int end = start + set->map[i].nr_queues; 3524 3525 if (hctx_idx >= start && hctx_idx < end) 3526 break; 3527 } 3528 3529 if (i >= set->nr_maps) 3530 i = HCTX_TYPE_DEFAULT; 3531 3532 return i; 3533 } 3534 3535 static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set, 3536 unsigned int hctx_idx) 3537 { 3538 enum hctx_type type = hctx_idx_to_type(set, hctx_idx); 3539 3540 return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx); 3541 } 3542 3543 static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, 3544 unsigned int hctx_idx, 3545 unsigned int nr_tags, 3546 unsigned int reserved_tags) 3547 { 3548 int node = blk_mq_get_hctx_node(set, hctx_idx); 3549 struct blk_mq_tags *tags; 3550 3551 if (node == NUMA_NO_NODE) 3552 node = set->numa_node; 3553 3554 tags = blk_mq_init_tags(nr_tags, reserved_tags, set->flags, node); 3555 if (!tags) 3556 return NULL; 3557 3558 tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *), 3559 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, 3560 node); 3561 if (!tags->rqs) 3562 goto err_free_tags; 3563 3564 tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *), 3565 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, 3566 node); 3567 if (!tags->static_rqs) 3568 goto err_free_rqs; 3569 3570 return tags; 3571 3572 err_free_rqs: 3573 kfree(tags->rqs); 3574 err_free_tags: 3575 blk_mq_free_tags(set, tags); 3576 return NULL; 3577 } 3578 3579 static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, 3580 unsigned int hctx_idx, int node) 3581 { 3582 int ret; 3583 3584 if (set->ops->init_request) { 3585 ret = set->ops->init_request(set, rq, hctx_idx, node); 3586 if (ret) 3587 return ret; 3588 } 3589 3590 WRITE_ONCE(rq->state, MQ_RQ_IDLE); 3591 return 0; 3592 } 3593 3594 static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, 3595 struct blk_mq_tags *tags, 3596 unsigned int hctx_idx, unsigned int depth) 3597 { 3598 unsigned int i, j, entries_per_page, max_order = 4; 3599 int node = blk_mq_get_hctx_node(set, hctx_idx); 3600 size_t rq_size, left; 3601 3602 if (node == NUMA_NO_NODE) 3603 node = set->numa_node; 3604 3605 /* 3606 * rq_size is the size of the request plus driver payload, rounded 3607 * to the cacheline size 3608 */ 3609 rq_size = round_up(sizeof(struct request) + set->cmd_size, 3610 cache_line_size()); 3611 left = rq_size * depth; 3612 3613 for (i = 0; i < depth; ) { 3614 int this_order = max_order; 3615 struct page *page; 3616 int to_do; 3617 void *p; 3618 3619 while (this_order && left < order_to_size(this_order - 1)) 3620 this_order--; 3621 3622 do { 3623 page = alloc_pages_node(node, 3624 GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO, 3625 this_order); 3626 if (page) 3627 break; 3628 if (!this_order--) 3629 break; 3630 if (order_to_size(this_order) < rq_size) 3631 break; 3632 } while (1); 3633 3634 if (!page) 3635 goto fail; 3636 3637 page->private = this_order; 3638 list_add_tail(&page->lru, &tags->page_list); 3639 3640 p = page_address(page); 3641 /* 3642 * Allow kmemleak to scan these pages as they contain pointers 3643 * to additional allocations like via ops->init_request(). 3644 */ 3645 kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO); 3646 entries_per_page = order_to_size(this_order) / rq_size; 3647 to_do = min(entries_per_page, depth - i); 3648 left -= to_do * rq_size; 3649 for (j = 0; j < to_do; j++) { 3650 struct request *rq = p; 3651 3652 tags->static_rqs[i] = rq; 3653 if (blk_mq_init_request(set, rq, hctx_idx, node)) { 3654 tags->static_rqs[i] = NULL; 3655 goto fail; 3656 } 3657 3658 p += rq_size; 3659 i++; 3660 } 3661 } 3662 return 0; 3663 3664 fail: 3665 blk_mq_free_rqs(set, tags, hctx_idx); 3666 return -ENOMEM; 3667 } 3668 3669 struct rq_iter_data { 3670 struct blk_mq_hw_ctx *hctx; 3671 bool has_rq; 3672 }; 3673 3674 static bool blk_mq_has_request(struct request *rq, void *data) 3675 { 3676 struct rq_iter_data *iter_data = data; 3677 3678 if (rq->mq_hctx != iter_data->hctx) 3679 return true; 3680 iter_data->has_rq = true; 3681 return false; 3682 } 3683 3684 static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx) 3685 { 3686 struct blk_mq_tags *tags = hctx->sched_tags ? 3687 hctx->sched_tags : hctx->tags; 3688 struct rq_iter_data data = { 3689 .hctx = hctx, 3690 }; 3691 int srcu_idx; 3692 3693 srcu_idx = srcu_read_lock(&hctx->queue->tag_set->tags_srcu); 3694 blk_mq_all_tag_iter(tags, blk_mq_has_request, &data); 3695 srcu_read_unlock(&hctx->queue->tag_set->tags_srcu, srcu_idx); 3696 3697 return data.has_rq; 3698 } 3699 3700 static bool blk_mq_hctx_has_online_cpu(struct blk_mq_hw_ctx *hctx, 3701 unsigned int this_cpu) 3702 { 3703 enum hctx_type type = hctx->type; 3704 int cpu; 3705 3706 /* 3707 * hctx->cpumask has to rule out isolated CPUs, but userspace still 3708 * might submit IOs on these isolated CPUs, so use the queue map to 3709 * check if all CPUs mapped to this hctx are offline 3710 */ 3711 for_each_online_cpu(cpu) { 3712 struct blk_mq_hw_ctx *h = blk_mq_map_queue_type(hctx->queue, 3713 type, cpu); 3714 3715 if (h != hctx) 3716 continue; 3717 3718 /* this hctx has at least one online CPU */ 3719 if (this_cpu != cpu) 3720 return true; 3721 } 3722 3723 return false; 3724 } 3725 3726 static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node) 3727 { 3728 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node, 3729 struct blk_mq_hw_ctx, cpuhp_online); 3730 int ret = 0; 3731 3732 if (!hctx->nr_ctx || blk_mq_hctx_has_online_cpu(hctx, cpu)) 3733 return 0; 3734 3735 /* 3736 * Prevent new request from being allocated on the current hctx. 3737 * 3738 * The smp_mb__after_atomic() Pairs with the implied barrier in 3739 * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is 3740 * seen once we return from the tag allocator. 3741 */ 3742 set_bit(BLK_MQ_S_INACTIVE, &hctx->state); 3743 smp_mb__after_atomic(); 3744 3745 /* 3746 * Try to grab a reference to the queue and wait for any outstanding 3747 * requests. If we could not grab a reference the queue has been 3748 * frozen and there are no requests. 3749 */ 3750 if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) { 3751 while (blk_mq_hctx_has_requests(hctx)) { 3752 /* 3753 * The wakeup capable IRQ handler of block device is 3754 * not called during suspend. Skip the loop by checking 3755 * pm_wakeup_pending to prevent the deadlock and improve 3756 * suspend latency. 3757 */ 3758 if (pm_wakeup_pending()) { 3759 clear_bit(BLK_MQ_S_INACTIVE, &hctx->state); 3760 ret = -EBUSY; 3761 break; 3762 } 3763 msleep(5); 3764 } 3765 percpu_ref_put(&hctx->queue->q_usage_counter); 3766 } 3767 3768 return ret; 3769 } 3770 3771 /* 3772 * Check if one CPU is mapped to the specified hctx 3773 * 3774 * Isolated CPUs have been ruled out from hctx->cpumask, which is supposed 3775 * to be used for scheduling kworker only. For other usage, please call this 3776 * helper for checking if one CPU belongs to the specified hctx 3777 */ 3778 static bool blk_mq_cpu_mapped_to_hctx(unsigned int cpu, 3779 const struct blk_mq_hw_ctx *hctx) 3780 { 3781 struct blk_mq_hw_ctx *mapped_hctx = blk_mq_map_queue_type(hctx->queue, 3782 hctx->type, cpu); 3783 3784 return mapped_hctx == hctx; 3785 } 3786 3787 static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node) 3788 { 3789 struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node, 3790 struct blk_mq_hw_ctx, cpuhp_online); 3791 3792 if (blk_mq_cpu_mapped_to_hctx(cpu, hctx)) 3793 clear_bit(BLK_MQ_S_INACTIVE, &hctx->state); 3794 return 0; 3795 } 3796 3797 /* 3798 * 'cpu' is going away. splice any existing rq_list entries from this 3799 * software queue to the hw queue dispatch list, and ensure that it 3800 * gets run. 3801 */ 3802 static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node) 3803 { 3804 struct blk_mq_hw_ctx *hctx; 3805 struct blk_mq_ctx *ctx; 3806 LIST_HEAD(tmp); 3807 enum hctx_type type; 3808 3809 hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead); 3810 if (!blk_mq_cpu_mapped_to_hctx(cpu, hctx)) 3811 return 0; 3812 3813 ctx = __blk_mq_get_ctx(hctx->queue, cpu); 3814 type = hctx->type; 3815 3816 spin_lock(&ctx->lock); 3817 if (!list_empty(&ctx->rq_lists[type])) { 3818 list_splice_init(&ctx->rq_lists[type], &tmp); 3819 blk_mq_hctx_clear_pending(hctx, ctx); 3820 } 3821 spin_unlock(&ctx->lock); 3822 3823 if (list_empty(&tmp)) 3824 return 0; 3825 3826 spin_lock(&hctx->lock); 3827 list_splice_tail_init(&tmp, &hctx->dispatch); 3828 spin_unlock(&hctx->lock); 3829 3830 blk_mq_run_hw_queue(hctx, true); 3831 return 0; 3832 } 3833 3834 static void __blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx) 3835 { 3836 lockdep_assert_held(&blk_mq_cpuhp_lock); 3837 3838 if (!(hctx->flags & BLK_MQ_F_STACKING) && 3839 !hlist_unhashed(&hctx->cpuhp_online)) { 3840 cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE, 3841 &hctx->cpuhp_online); 3842 INIT_HLIST_NODE(&hctx->cpuhp_online); 3843 } 3844 3845 if (!hlist_unhashed(&hctx->cpuhp_dead)) { 3846 cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD, 3847 &hctx->cpuhp_dead); 3848 INIT_HLIST_NODE(&hctx->cpuhp_dead); 3849 } 3850 } 3851 3852 static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx) 3853 { 3854 mutex_lock(&blk_mq_cpuhp_lock); 3855 __blk_mq_remove_cpuhp(hctx); 3856 mutex_unlock(&blk_mq_cpuhp_lock); 3857 } 3858 3859 static void __blk_mq_add_cpuhp(struct blk_mq_hw_ctx *hctx) 3860 { 3861 lockdep_assert_held(&blk_mq_cpuhp_lock); 3862 3863 if (!(hctx->flags & BLK_MQ_F_STACKING) && 3864 hlist_unhashed(&hctx->cpuhp_online)) 3865 cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE, 3866 &hctx->cpuhp_online); 3867 3868 if (hlist_unhashed(&hctx->cpuhp_dead)) 3869 cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, 3870 &hctx->cpuhp_dead); 3871 } 3872 3873 static void __blk_mq_remove_cpuhp_list(struct list_head *head) 3874 { 3875 struct blk_mq_hw_ctx *hctx; 3876 3877 lockdep_assert_held(&blk_mq_cpuhp_lock); 3878 3879 list_for_each_entry(hctx, head, hctx_list) 3880 __blk_mq_remove_cpuhp(hctx); 3881 } 3882 3883 /* 3884 * Unregister cpuhp callbacks from exited hw queues 3885 * 3886 * Safe to call if this `request_queue` is live 3887 */ 3888 static void blk_mq_remove_hw_queues_cpuhp(struct request_queue *q) 3889 { 3890 LIST_HEAD(hctx_list); 3891 3892 spin_lock(&q->unused_hctx_lock); 3893 list_splice_init(&q->unused_hctx_list, &hctx_list); 3894 spin_unlock(&q->unused_hctx_lock); 3895 3896 mutex_lock(&blk_mq_cpuhp_lock); 3897 __blk_mq_remove_cpuhp_list(&hctx_list); 3898 mutex_unlock(&blk_mq_cpuhp_lock); 3899 3900 spin_lock(&q->unused_hctx_lock); 3901 list_splice(&hctx_list, &q->unused_hctx_list); 3902 spin_unlock(&q->unused_hctx_lock); 3903 } 3904 3905 /* 3906 * Register cpuhp callbacks from all hw queues 3907 * 3908 * Safe to call if this `request_queue` is live 3909 */ 3910 static void blk_mq_add_hw_queues_cpuhp(struct request_queue *q) 3911 { 3912 struct blk_mq_hw_ctx *hctx; 3913 unsigned long i; 3914 3915 mutex_lock(&blk_mq_cpuhp_lock); 3916 queue_for_each_hw_ctx(q, hctx, i) 3917 __blk_mq_add_cpuhp(hctx); 3918 mutex_unlock(&blk_mq_cpuhp_lock); 3919 } 3920 3921 /* 3922 * Before freeing hw queue, clearing the flush request reference in 3923 * tags->rqs[] for avoiding potential UAF. 3924 */ 3925 static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags, 3926 unsigned int queue_depth, struct request *flush_rq) 3927 { 3928 int i; 3929 3930 /* The hw queue may not be mapped yet */ 3931 if (!tags) 3932 return; 3933 3934 WARN_ON_ONCE(req_ref_read(flush_rq) != 0); 3935 3936 for (i = 0; i < queue_depth; i++) 3937 cmpxchg(&tags->rqs[i], flush_rq, NULL); 3938 } 3939 3940 static void blk_free_flush_queue_callback(struct rcu_head *head) 3941 { 3942 struct blk_flush_queue *fq = 3943 container_of(head, struct blk_flush_queue, rcu_head); 3944 3945 blk_free_flush_queue(fq); 3946 } 3947 3948 /* hctx->ctxs will be freed in queue's release handler */ 3949 static void blk_mq_exit_hctx(struct request_queue *q, 3950 struct blk_mq_tag_set *set, 3951 struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) 3952 { 3953 struct request *flush_rq = hctx->fq->flush_rq; 3954 3955 if (blk_mq_hw_queue_mapped(hctx)) 3956 blk_mq_tag_idle(hctx); 3957 3958 if (blk_queue_init_done(q)) 3959 blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx], 3960 set->queue_depth, flush_rq); 3961 if (set->ops->exit_request) 3962 set->ops->exit_request(set, flush_rq, hctx_idx); 3963 3964 if (set->ops->exit_hctx) 3965 set->ops->exit_hctx(hctx, hctx_idx); 3966 3967 call_srcu(&set->tags_srcu, &hctx->fq->rcu_head, 3968 blk_free_flush_queue_callback); 3969 hctx->fq = NULL; 3970 3971 xa_erase(&q->hctx_table, hctx_idx); 3972 3973 spin_lock(&q->unused_hctx_lock); 3974 list_add(&hctx->hctx_list, &q->unused_hctx_list); 3975 spin_unlock(&q->unused_hctx_lock); 3976 } 3977 3978 static void blk_mq_exit_hw_queues(struct request_queue *q, 3979 struct blk_mq_tag_set *set, int nr_queue) 3980 { 3981 struct blk_mq_hw_ctx *hctx; 3982 unsigned long i; 3983 3984 queue_for_each_hw_ctx(q, hctx, i) { 3985 if (i == nr_queue) 3986 break; 3987 blk_mq_remove_cpuhp(hctx); 3988 blk_mq_exit_hctx(q, set, hctx, i); 3989 } 3990 } 3991 3992 static int blk_mq_init_hctx(struct request_queue *q, 3993 struct blk_mq_tag_set *set, 3994 struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) 3995 { 3996 gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY; 3997 3998 hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp); 3999 if (!hctx->fq) 4000 goto fail; 4001 4002 hctx->queue_num = hctx_idx; 4003 4004 hctx->tags = set->tags[hctx_idx]; 4005 4006 if (set->ops->init_hctx && 4007 set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) 4008 goto fail_free_fq; 4009 4010 if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx, 4011 hctx->numa_node)) 4012 goto exit_hctx; 4013 4014 if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL)) 4015 goto exit_flush_rq; 4016 4017 return 0; 4018 4019 exit_flush_rq: 4020 if (set->ops->exit_request) 4021 set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx); 4022 exit_hctx: 4023 if (set->ops->exit_hctx) 4024 set->ops->exit_hctx(hctx, hctx_idx); 4025 fail_free_fq: 4026 blk_free_flush_queue(hctx->fq); 4027 hctx->fq = NULL; 4028 fail: 4029 return -1; 4030 } 4031 4032 static struct blk_mq_hw_ctx * 4033 blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set, 4034 int node) 4035 { 4036 struct blk_mq_hw_ctx *hctx; 4037 gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY; 4038 4039 hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node); 4040 if (!hctx) 4041 goto fail_alloc_hctx; 4042 4043 if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node)) 4044 goto free_hctx; 4045 4046 atomic_set(&hctx->nr_active, 0); 4047 if (node == NUMA_NO_NODE) 4048 node = set->numa_node; 4049 hctx->numa_node = node; 4050 4051 INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); 4052 spin_lock_init(&hctx->lock); 4053 INIT_LIST_HEAD(&hctx->dispatch); 4054 INIT_HLIST_NODE(&hctx->cpuhp_dead); 4055 INIT_HLIST_NODE(&hctx->cpuhp_online); 4056 hctx->queue = q; 4057 hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED; 4058 4059 INIT_LIST_HEAD(&hctx->hctx_list); 4060 4061 /* 4062 * Allocate space for all possible cpus to avoid allocation at 4063 * runtime 4064 */ 4065 hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *), 4066 gfp, node); 4067 if (!hctx->ctxs) 4068 goto free_cpumask; 4069 4070 if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), 4071 gfp, node, false, false)) 4072 goto free_ctxs; 4073 hctx->nr_ctx = 0; 4074 4075 spin_lock_init(&hctx->dispatch_wait_lock); 4076 init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake); 4077 INIT_LIST_HEAD(&hctx->dispatch_wait.entry); 4078 4079 blk_mq_hctx_kobj_init(hctx); 4080 4081 return hctx; 4082 4083 free_ctxs: 4084 kfree(hctx->ctxs); 4085 free_cpumask: 4086 free_cpumask_var(hctx->cpumask); 4087 free_hctx: 4088 kfree(hctx); 4089 fail_alloc_hctx: 4090 return NULL; 4091 } 4092 4093 static void blk_mq_init_cpu_queues(struct request_queue *q, 4094 unsigned int nr_hw_queues) 4095 { 4096 struct blk_mq_tag_set *set = q->tag_set; 4097 unsigned int i, j; 4098 4099 for_each_possible_cpu(i) { 4100 struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); 4101 struct blk_mq_hw_ctx *hctx; 4102 int k; 4103 4104 __ctx->cpu = i; 4105 spin_lock_init(&__ctx->lock); 4106 for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++) 4107 INIT_LIST_HEAD(&__ctx->rq_lists[k]); 4108 4109 __ctx->queue = q; 4110 4111 /* 4112 * Set local node, IFF we have more than one hw queue. If 4113 * not, we remain on the home node of the device 4114 */ 4115 for (j = 0; j < set->nr_maps; j++) { 4116 hctx = blk_mq_map_queue_type(q, j, i); 4117 if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) 4118 hctx->numa_node = cpu_to_node(i); 4119 } 4120 } 4121 } 4122 4123 struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set, 4124 unsigned int hctx_idx, 4125 unsigned int depth) 4126 { 4127 struct blk_mq_tags *tags; 4128 int ret; 4129 4130 tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags); 4131 if (!tags) 4132 return NULL; 4133 4134 ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth); 4135 if (ret) { 4136 blk_mq_free_rq_map(set, tags); 4137 return NULL; 4138 } 4139 4140 return tags; 4141 } 4142 4143 static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set, 4144 int hctx_idx) 4145 { 4146 if (blk_mq_is_shared_tags(set->flags)) { 4147 set->tags[hctx_idx] = set->shared_tags; 4148 4149 return true; 4150 } 4151 4152 set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx, 4153 set->queue_depth); 4154 4155 return set->tags[hctx_idx]; 4156 } 4157 4158 void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set, 4159 struct blk_mq_tags *tags, 4160 unsigned int hctx_idx) 4161 { 4162 if (tags) { 4163 blk_mq_free_rqs(set, tags, hctx_idx); 4164 blk_mq_free_rq_map(set, tags); 4165 } 4166 } 4167 4168 static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set, 4169 unsigned int hctx_idx) 4170 { 4171 if (!blk_mq_is_shared_tags(set->flags)) 4172 blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx); 4173 4174 set->tags[hctx_idx] = NULL; 4175 } 4176 4177 static void blk_mq_map_swqueue(struct request_queue *q) 4178 { 4179 unsigned int j, hctx_idx; 4180 unsigned long i; 4181 struct blk_mq_hw_ctx *hctx; 4182 struct blk_mq_ctx *ctx; 4183 struct blk_mq_tag_set *set = q->tag_set; 4184 4185 queue_for_each_hw_ctx(q, hctx, i) { 4186 cpumask_clear(hctx->cpumask); 4187 hctx->nr_ctx = 0; 4188 hctx->dispatch_from = NULL; 4189 } 4190 4191 /* 4192 * Map software to hardware queues. 4193 * 4194 * If the cpu isn't present, the cpu is mapped to first hctx. 4195 */ 4196 for_each_possible_cpu(i) { 4197 4198 ctx = per_cpu_ptr(q->queue_ctx, i); 4199 for (j = 0; j < set->nr_maps; j++) { 4200 if (!set->map[j].nr_queues) { 4201 ctx->hctxs[j] = blk_mq_map_queue_type(q, 4202 HCTX_TYPE_DEFAULT, i); 4203 continue; 4204 } 4205 hctx_idx = set->map[j].mq_map[i]; 4206 /* unmapped hw queue can be remapped after CPU topo changed */ 4207 if (!set->tags[hctx_idx] && 4208 !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) { 4209 /* 4210 * If tags initialization fail for some hctx, 4211 * that hctx won't be brought online. In this 4212 * case, remap the current ctx to hctx[0] which 4213 * is guaranteed to always have tags allocated 4214 */ 4215 set->map[j].mq_map[i] = 0; 4216 } 4217 4218 hctx = blk_mq_map_queue_type(q, j, i); 4219 ctx->hctxs[j] = hctx; 4220 /* 4221 * If the CPU is already set in the mask, then we've 4222 * mapped this one already. This can happen if 4223 * devices share queues across queue maps. 4224 */ 4225 if (cpumask_test_cpu(i, hctx->cpumask)) 4226 continue; 4227 4228 cpumask_set_cpu(i, hctx->cpumask); 4229 hctx->type = j; 4230 ctx->index_hw[hctx->type] = hctx->nr_ctx; 4231 hctx->ctxs[hctx->nr_ctx++] = ctx; 4232 4233 /* 4234 * If the nr_ctx type overflows, we have exceeded the 4235 * amount of sw queues we can support. 4236 */ 4237 BUG_ON(!hctx->nr_ctx); 4238 } 4239 4240 for (; j < HCTX_MAX_TYPES; j++) 4241 ctx->hctxs[j] = blk_mq_map_queue_type(q, 4242 HCTX_TYPE_DEFAULT, i); 4243 } 4244 4245 queue_for_each_hw_ctx(q, hctx, i) { 4246 int cpu; 4247 4248 /* 4249 * If no software queues are mapped to this hardware queue, 4250 * disable it and free the request entries. 4251 */ 4252 if (!hctx->nr_ctx) { 4253 /* Never unmap queue 0. We need it as a 4254 * fallback in case of a new remap fails 4255 * allocation 4256 */ 4257 if (i) 4258 __blk_mq_free_map_and_rqs(set, i); 4259 4260 hctx->tags = NULL; 4261 continue; 4262 } 4263 4264 hctx->tags = set->tags[i]; 4265 WARN_ON(!hctx->tags); 4266 4267 /* 4268 * Set the map size to the number of mapped software queues. 4269 * This is more accurate and more efficient than looping 4270 * over all possibly mapped software queues. 4271 */ 4272 sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx); 4273 4274 /* 4275 * Rule out isolated CPUs from hctx->cpumask to avoid 4276 * running block kworker on isolated CPUs 4277 */ 4278 for_each_cpu(cpu, hctx->cpumask) { 4279 if (cpu_is_isolated(cpu)) 4280 cpumask_clear_cpu(cpu, hctx->cpumask); 4281 } 4282 4283 /* 4284 * Initialize batch roundrobin counts 4285 */ 4286 hctx->next_cpu = blk_mq_first_mapped_cpu(hctx); 4287 hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; 4288 } 4289 } 4290 4291 /* 4292 * Caller needs to ensure that we're either frozen/quiesced, or that 4293 * the queue isn't live yet. 4294 */ 4295 static void queue_set_hctx_shared(struct request_queue *q, bool shared) 4296 { 4297 struct blk_mq_hw_ctx *hctx; 4298 unsigned long i; 4299 4300 queue_for_each_hw_ctx(q, hctx, i) { 4301 if (shared) { 4302 hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED; 4303 } else { 4304 blk_mq_tag_idle(hctx); 4305 hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED; 4306 } 4307 } 4308 } 4309 4310 static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set, 4311 bool shared) 4312 { 4313 struct request_queue *q; 4314 unsigned int memflags; 4315 4316 lockdep_assert_held(&set->tag_list_lock); 4317 4318 list_for_each_entry(q, &set->tag_list, tag_set_list) { 4319 memflags = blk_mq_freeze_queue(q); 4320 queue_set_hctx_shared(q, shared); 4321 blk_mq_unfreeze_queue(q, memflags); 4322 } 4323 } 4324 4325 static void blk_mq_del_queue_tag_set(struct request_queue *q) 4326 { 4327 struct blk_mq_tag_set *set = q->tag_set; 4328 4329 mutex_lock(&set->tag_list_lock); 4330 list_del_rcu(&q->tag_set_list); 4331 if (list_is_singular(&set->tag_list)) { 4332 /* just transitioned to unshared */ 4333 set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED; 4334 /* update existing queue */ 4335 blk_mq_update_tag_set_shared(set, false); 4336 } 4337 mutex_unlock(&set->tag_list_lock); 4338 } 4339 4340 static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, 4341 struct request_queue *q) 4342 { 4343 mutex_lock(&set->tag_list_lock); 4344 4345 /* 4346 * Check to see if we're transitioning to shared (from 1 to 2 queues). 4347 */ 4348 if (!list_empty(&set->tag_list) && 4349 !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) { 4350 set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED; 4351 /* update existing queue */ 4352 blk_mq_update_tag_set_shared(set, true); 4353 } 4354 if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED) 4355 queue_set_hctx_shared(q, true); 4356 list_add_tail_rcu(&q->tag_set_list, &set->tag_list); 4357 4358 mutex_unlock(&set->tag_list_lock); 4359 } 4360 4361 /* All allocations will be freed in release handler of q->mq_kobj */ 4362 static int blk_mq_alloc_ctxs(struct request_queue *q) 4363 { 4364 struct blk_mq_ctxs *ctxs; 4365 int cpu; 4366 4367 ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL); 4368 if (!ctxs) 4369 return -ENOMEM; 4370 4371 ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx); 4372 if (!ctxs->queue_ctx) 4373 goto fail; 4374 4375 for_each_possible_cpu(cpu) { 4376 struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu); 4377 ctx->ctxs = ctxs; 4378 } 4379 4380 q->mq_kobj = &ctxs->kobj; 4381 q->queue_ctx = ctxs->queue_ctx; 4382 4383 return 0; 4384 fail: 4385 kfree(ctxs); 4386 return -ENOMEM; 4387 } 4388 4389 /* 4390 * It is the actual release handler for mq, but we do it from 4391 * request queue's release handler for avoiding use-after-free 4392 * and headache because q->mq_kobj shouldn't have been introduced, 4393 * but we can't group ctx/kctx kobj without it. 4394 */ 4395 void blk_mq_release(struct request_queue *q) 4396 { 4397 struct blk_mq_hw_ctx *hctx, *next; 4398 unsigned long i; 4399 4400 queue_for_each_hw_ctx(q, hctx, i) 4401 WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list)); 4402 4403 /* all hctx are in .unused_hctx_list now */ 4404 list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) { 4405 list_del_init(&hctx->hctx_list); 4406 kobject_put(&hctx->kobj); 4407 } 4408 4409 xa_destroy(&q->hctx_table); 4410 4411 /* 4412 * release .mq_kobj and sw queue's kobject now because 4413 * both share lifetime with request queue. 4414 */ 4415 blk_mq_sysfs_deinit(q); 4416 } 4417 4418 struct request_queue *blk_mq_alloc_queue(struct blk_mq_tag_set *set, 4419 struct queue_limits *lim, void *queuedata) 4420 { 4421 struct queue_limits default_lim = { }; 4422 struct request_queue *q; 4423 int ret; 4424 4425 if (!lim) 4426 lim = &default_lim; 4427 lim->features |= BLK_FEAT_IO_STAT | BLK_FEAT_NOWAIT; 4428 if (set->nr_maps > HCTX_TYPE_POLL) 4429 lim->features |= BLK_FEAT_POLL; 4430 4431 q = blk_alloc_queue(lim, set->numa_node); 4432 if (IS_ERR(q)) 4433 return q; 4434 q->queuedata = queuedata; 4435 ret = blk_mq_init_allocated_queue(set, q); 4436 if (ret) { 4437 blk_put_queue(q); 4438 return ERR_PTR(ret); 4439 } 4440 return q; 4441 } 4442 EXPORT_SYMBOL(blk_mq_alloc_queue); 4443 4444 /** 4445 * blk_mq_destroy_queue - shutdown a request queue 4446 * @q: request queue to shutdown 4447 * 4448 * This shuts down a request queue allocated by blk_mq_alloc_queue(). All future 4449 * requests will be failed with -ENODEV. The caller is responsible for dropping 4450 * the reference from blk_mq_alloc_queue() by calling blk_put_queue(). 4451 * 4452 * Context: can sleep 4453 */ 4454 void blk_mq_destroy_queue(struct request_queue *q) 4455 { 4456 WARN_ON_ONCE(!queue_is_mq(q)); 4457 WARN_ON_ONCE(blk_queue_registered(q)); 4458 4459 might_sleep(); 4460 4461 blk_queue_flag_set(QUEUE_FLAG_DYING, q); 4462 blk_queue_start_drain(q); 4463 blk_mq_freeze_queue_wait(q); 4464 4465 blk_sync_queue(q); 4466 blk_mq_cancel_work_sync(q); 4467 blk_mq_exit_queue(q); 4468 } 4469 EXPORT_SYMBOL(blk_mq_destroy_queue); 4470 4471 struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, 4472 struct queue_limits *lim, void *queuedata, 4473 struct lock_class_key *lkclass) 4474 { 4475 struct request_queue *q; 4476 struct gendisk *disk; 4477 4478 q = blk_mq_alloc_queue(set, lim, queuedata); 4479 if (IS_ERR(q)) 4480 return ERR_CAST(q); 4481 4482 disk = __alloc_disk_node(q, set->numa_node, lkclass); 4483 if (!disk) { 4484 blk_mq_destroy_queue(q); 4485 blk_put_queue(q); 4486 return ERR_PTR(-ENOMEM); 4487 } 4488 set_bit(GD_OWNS_QUEUE, &disk->state); 4489 return disk; 4490 } 4491 EXPORT_SYMBOL(__blk_mq_alloc_disk); 4492 4493 struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q, 4494 struct lock_class_key *lkclass) 4495 { 4496 struct gendisk *disk; 4497 4498 if (!blk_get_queue(q)) 4499 return NULL; 4500 disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass); 4501 if (!disk) 4502 blk_put_queue(q); 4503 return disk; 4504 } 4505 EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue); 4506 4507 /* 4508 * Only hctx removed from cpuhp list can be reused 4509 */ 4510 static bool blk_mq_hctx_is_reusable(struct blk_mq_hw_ctx *hctx) 4511 { 4512 return hlist_unhashed(&hctx->cpuhp_online) && 4513 hlist_unhashed(&hctx->cpuhp_dead); 4514 } 4515 4516 static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx( 4517 struct blk_mq_tag_set *set, struct request_queue *q, 4518 int hctx_idx, int node) 4519 { 4520 struct blk_mq_hw_ctx *hctx = NULL, *tmp; 4521 4522 /* reuse dead hctx first */ 4523 spin_lock(&q->unused_hctx_lock); 4524 list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) { 4525 if (tmp->numa_node == node && blk_mq_hctx_is_reusable(tmp)) { 4526 hctx = tmp; 4527 break; 4528 } 4529 } 4530 if (hctx) 4531 list_del_init(&hctx->hctx_list); 4532 spin_unlock(&q->unused_hctx_lock); 4533 4534 if (!hctx) 4535 hctx = blk_mq_alloc_hctx(q, set, node); 4536 if (!hctx) 4537 goto fail; 4538 4539 if (blk_mq_init_hctx(q, set, hctx, hctx_idx)) 4540 goto free_hctx; 4541 4542 return hctx; 4543 4544 free_hctx: 4545 kobject_put(&hctx->kobj); 4546 fail: 4547 return NULL; 4548 } 4549 4550 static void __blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, 4551 struct request_queue *q) 4552 { 4553 struct blk_mq_hw_ctx *hctx; 4554 unsigned long i, j; 4555 4556 for (i = 0; i < set->nr_hw_queues; i++) { 4557 int old_node; 4558 int node = blk_mq_get_hctx_node(set, i); 4559 struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i); 4560 4561 if (old_hctx) { 4562 old_node = old_hctx->numa_node; 4563 blk_mq_exit_hctx(q, set, old_hctx, i); 4564 } 4565 4566 if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) { 4567 if (!old_hctx) 4568 break; 4569 pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n", 4570 node, old_node); 4571 hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node); 4572 WARN_ON_ONCE(!hctx); 4573 } 4574 } 4575 /* 4576 * Increasing nr_hw_queues fails. Free the newly allocated 4577 * hctxs and keep the previous q->nr_hw_queues. 4578 */ 4579 if (i != set->nr_hw_queues) { 4580 j = q->nr_hw_queues; 4581 } else { 4582 j = i; 4583 q->nr_hw_queues = set->nr_hw_queues; 4584 } 4585 4586 xa_for_each_start(&q->hctx_table, j, hctx, j) 4587 blk_mq_exit_hctx(q, set, hctx, j); 4588 } 4589 4590 static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, 4591 struct request_queue *q) 4592 { 4593 __blk_mq_realloc_hw_ctxs(set, q); 4594 4595 /* unregister cpuhp callbacks for exited hctxs */ 4596 blk_mq_remove_hw_queues_cpuhp(q); 4597 4598 /* register cpuhp for new initialized hctxs */ 4599 blk_mq_add_hw_queues_cpuhp(q); 4600 } 4601 4602 int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, 4603 struct request_queue *q) 4604 { 4605 /* mark the queue as mq asap */ 4606 q->mq_ops = set->ops; 4607 4608 /* 4609 * ->tag_set has to be setup before initialize hctx, which cpuphp 4610 * handler needs it for checking queue mapping 4611 */ 4612 q->tag_set = set; 4613 4614 if (blk_mq_alloc_ctxs(q)) 4615 goto err_exit; 4616 4617 /* init q->mq_kobj and sw queues' kobjects */ 4618 blk_mq_sysfs_init(q); 4619 4620 INIT_LIST_HEAD(&q->unused_hctx_list); 4621 spin_lock_init(&q->unused_hctx_lock); 4622 4623 xa_init(&q->hctx_table); 4624 4625 blk_mq_realloc_hw_ctxs(set, q); 4626 if (!q->nr_hw_queues) 4627 goto err_hctxs; 4628 4629 INIT_WORK(&q->timeout_work, blk_mq_timeout_work); 4630 blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); 4631 4632 q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; 4633 4634 INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work); 4635 INIT_LIST_HEAD(&q->flush_list); 4636 INIT_LIST_HEAD(&q->requeue_list); 4637 spin_lock_init(&q->requeue_lock); 4638 4639 q->nr_requests = set->queue_depth; 4640 4641 blk_mq_init_cpu_queues(q, set->nr_hw_queues); 4642 blk_mq_map_swqueue(q); 4643 blk_mq_add_queue_tag_set(set, q); 4644 return 0; 4645 4646 err_hctxs: 4647 blk_mq_release(q); 4648 err_exit: 4649 q->mq_ops = NULL; 4650 return -ENOMEM; 4651 } 4652 EXPORT_SYMBOL(blk_mq_init_allocated_queue); 4653 4654 /* tags can _not_ be used after returning from blk_mq_exit_queue */ 4655 void blk_mq_exit_queue(struct request_queue *q) 4656 { 4657 struct blk_mq_tag_set *set = q->tag_set; 4658 4659 /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */ 4660 blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); 4661 /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */ 4662 blk_mq_del_queue_tag_set(q); 4663 } 4664 4665 static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) 4666 { 4667 int i; 4668 4669 if (blk_mq_is_shared_tags(set->flags)) { 4670 set->shared_tags = blk_mq_alloc_map_and_rqs(set, 4671 BLK_MQ_NO_HCTX_IDX, 4672 set->queue_depth); 4673 if (!set->shared_tags) 4674 return -ENOMEM; 4675 } 4676 4677 for (i = 0; i < set->nr_hw_queues; i++) { 4678 if (!__blk_mq_alloc_map_and_rqs(set, i)) 4679 goto out_unwind; 4680 cond_resched(); 4681 } 4682 4683 return 0; 4684 4685 out_unwind: 4686 while (--i >= 0) 4687 __blk_mq_free_map_and_rqs(set, i); 4688 4689 if (blk_mq_is_shared_tags(set->flags)) { 4690 blk_mq_free_map_and_rqs(set, set->shared_tags, 4691 BLK_MQ_NO_HCTX_IDX); 4692 } 4693 4694 return -ENOMEM; 4695 } 4696 4697 /* 4698 * Allocate the request maps associated with this tag_set. Note that this 4699 * may reduce the depth asked for, if memory is tight. set->queue_depth 4700 * will be updated to reflect the allocated depth. 4701 */ 4702 static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set) 4703 { 4704 unsigned int depth; 4705 int err; 4706 4707 depth = set->queue_depth; 4708 do { 4709 err = __blk_mq_alloc_rq_maps(set); 4710 if (!err) 4711 break; 4712 4713 set->queue_depth >>= 1; 4714 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { 4715 err = -ENOMEM; 4716 break; 4717 } 4718 } while (set->queue_depth); 4719 4720 if (!set->queue_depth || err) { 4721 pr_err("blk-mq: failed to allocate request map\n"); 4722 return -ENOMEM; 4723 } 4724 4725 if (depth != set->queue_depth) 4726 pr_info("blk-mq: reduced tag depth (%u -> %u)\n", 4727 depth, set->queue_depth); 4728 4729 return 0; 4730 } 4731 4732 static void blk_mq_update_queue_map(struct blk_mq_tag_set *set) 4733 { 4734 /* 4735 * blk_mq_map_queues() and multiple .map_queues() implementations 4736 * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the 4737 * number of hardware queues. 4738 */ 4739 if (set->nr_maps == 1) 4740 set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues; 4741 4742 if (set->ops->map_queues) { 4743 int i; 4744 4745 /* 4746 * transport .map_queues is usually done in the following 4747 * way: 4748 * 4749 * for (queue = 0; queue < set->nr_hw_queues; queue++) { 4750 * mask = get_cpu_mask(queue) 4751 * for_each_cpu(cpu, mask) 4752 * set->map[x].mq_map[cpu] = queue; 4753 * } 4754 * 4755 * When we need to remap, the table has to be cleared for 4756 * killing stale mapping since one CPU may not be mapped 4757 * to any hw queue. 4758 */ 4759 for (i = 0; i < set->nr_maps; i++) 4760 blk_mq_clear_mq_map(&set->map[i]); 4761 4762 set->ops->map_queues(set); 4763 } else { 4764 BUG_ON(set->nr_maps > 1); 4765 blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); 4766 } 4767 } 4768 4769 static struct blk_mq_tags **blk_mq_prealloc_tag_set_tags( 4770 struct blk_mq_tag_set *set, 4771 int new_nr_hw_queues) 4772 { 4773 struct blk_mq_tags **new_tags; 4774 int i; 4775 4776 if (set->nr_hw_queues >= new_nr_hw_queues) 4777 return NULL; 4778 4779 new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *), 4780 GFP_KERNEL, set->numa_node); 4781 if (!new_tags) 4782 return ERR_PTR(-ENOMEM); 4783 4784 if (set->tags) 4785 memcpy(new_tags, set->tags, set->nr_hw_queues * 4786 sizeof(*set->tags)); 4787 4788 for (i = set->nr_hw_queues; i < new_nr_hw_queues; i++) { 4789 if (blk_mq_is_shared_tags(set->flags)) { 4790 new_tags[i] = set->shared_tags; 4791 } else { 4792 new_tags[i] = blk_mq_alloc_map_and_rqs(set, i, 4793 set->queue_depth); 4794 if (!new_tags[i]) 4795 goto out_unwind; 4796 } 4797 cond_resched(); 4798 } 4799 4800 return new_tags; 4801 out_unwind: 4802 while (--i >= set->nr_hw_queues) { 4803 if (!blk_mq_is_shared_tags(set->flags)) 4804 blk_mq_free_map_and_rqs(set, new_tags[i], i); 4805 } 4806 kfree(new_tags); 4807 return ERR_PTR(-ENOMEM); 4808 } 4809 4810 /* 4811 * Alloc a tag set to be associated with one or more request queues. 4812 * May fail with EINVAL for various error conditions. May adjust the 4813 * requested depth down, if it's too large. In that case, the set 4814 * value will be stored in set->queue_depth. 4815 */ 4816 int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) 4817 { 4818 int i, ret; 4819 4820 BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); 4821 4822 if (!set->nr_hw_queues) 4823 return -EINVAL; 4824 if (!set->queue_depth) 4825 return -EINVAL; 4826 if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) 4827 return -EINVAL; 4828 4829 if (!set->ops->queue_rq) 4830 return -EINVAL; 4831 4832 if (!set->ops->get_budget ^ !set->ops->put_budget) 4833 return -EINVAL; 4834 4835 if (set->queue_depth > BLK_MQ_MAX_DEPTH) { 4836 pr_info("blk-mq: reduced tag depth to %u\n", 4837 BLK_MQ_MAX_DEPTH); 4838 set->queue_depth = BLK_MQ_MAX_DEPTH; 4839 } 4840 4841 if (!set->nr_maps) 4842 set->nr_maps = 1; 4843 else if (set->nr_maps > HCTX_MAX_TYPES) 4844 return -EINVAL; 4845 4846 /* 4847 * If a crashdump is active, then we are potentially in a very 4848 * memory constrained environment. Limit us to 64 tags to prevent 4849 * using too much memory. 4850 */ 4851 if (is_kdump_kernel()) 4852 set->queue_depth = min(64U, set->queue_depth); 4853 4854 /* 4855 * There is no use for more h/w queues than cpus if we just have 4856 * a single map 4857 */ 4858 if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids) 4859 set->nr_hw_queues = nr_cpu_ids; 4860 4861 if (set->flags & BLK_MQ_F_BLOCKING) { 4862 set->srcu = kmalloc(sizeof(*set->srcu), GFP_KERNEL); 4863 if (!set->srcu) 4864 return -ENOMEM; 4865 ret = init_srcu_struct(set->srcu); 4866 if (ret) 4867 goto out_free_srcu; 4868 } 4869 ret = init_srcu_struct(&set->tags_srcu); 4870 if (ret) 4871 goto out_cleanup_srcu; 4872 4873 init_rwsem(&set->update_nr_hwq_lock); 4874 4875 ret = -ENOMEM; 4876 set->tags = kcalloc_node(set->nr_hw_queues, 4877 sizeof(struct blk_mq_tags *), GFP_KERNEL, 4878 set->numa_node); 4879 if (!set->tags) 4880 goto out_cleanup_tags_srcu; 4881 4882 for (i = 0; i < set->nr_maps; i++) { 4883 set->map[i].mq_map = kcalloc_node(nr_cpu_ids, 4884 sizeof(set->map[i].mq_map[0]), 4885 GFP_KERNEL, set->numa_node); 4886 if (!set->map[i].mq_map) 4887 goto out_free_mq_map; 4888 set->map[i].nr_queues = set->nr_hw_queues; 4889 } 4890 4891 blk_mq_update_queue_map(set); 4892 4893 ret = blk_mq_alloc_set_map_and_rqs(set); 4894 if (ret) 4895 goto out_free_mq_map; 4896 4897 mutex_init(&set->tag_list_lock); 4898 INIT_LIST_HEAD(&set->tag_list); 4899 4900 return 0; 4901 4902 out_free_mq_map: 4903 for (i = 0; i < set->nr_maps; i++) { 4904 kfree(set->map[i].mq_map); 4905 set->map[i].mq_map = NULL; 4906 } 4907 kfree(set->tags); 4908 set->tags = NULL; 4909 out_cleanup_tags_srcu: 4910 cleanup_srcu_struct(&set->tags_srcu); 4911 out_cleanup_srcu: 4912 if (set->flags & BLK_MQ_F_BLOCKING) 4913 cleanup_srcu_struct(set->srcu); 4914 out_free_srcu: 4915 if (set->flags & BLK_MQ_F_BLOCKING) 4916 kfree(set->srcu); 4917 return ret; 4918 } 4919 EXPORT_SYMBOL(blk_mq_alloc_tag_set); 4920 4921 /* allocate and initialize a tagset for a simple single-queue device */ 4922 int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set, 4923 const struct blk_mq_ops *ops, unsigned int queue_depth, 4924 unsigned int set_flags) 4925 { 4926 memset(set, 0, sizeof(*set)); 4927 set->ops = ops; 4928 set->nr_hw_queues = 1; 4929 set->nr_maps = 1; 4930 set->queue_depth = queue_depth; 4931 set->numa_node = NUMA_NO_NODE; 4932 set->flags = set_flags; 4933 return blk_mq_alloc_tag_set(set); 4934 } 4935 EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set); 4936 4937 void blk_mq_free_tag_set(struct blk_mq_tag_set *set) 4938 { 4939 int i, j; 4940 4941 for (i = 0; i < set->nr_hw_queues; i++) 4942 __blk_mq_free_map_and_rqs(set, i); 4943 4944 if (blk_mq_is_shared_tags(set->flags)) { 4945 blk_mq_free_map_and_rqs(set, set->shared_tags, 4946 BLK_MQ_NO_HCTX_IDX); 4947 } 4948 4949 for (j = 0; j < set->nr_maps; j++) { 4950 kfree(set->map[j].mq_map); 4951 set->map[j].mq_map = NULL; 4952 } 4953 4954 kfree(set->tags); 4955 set->tags = NULL; 4956 4957 srcu_barrier(&set->tags_srcu); 4958 cleanup_srcu_struct(&set->tags_srcu); 4959 if (set->flags & BLK_MQ_F_BLOCKING) { 4960 cleanup_srcu_struct(set->srcu); 4961 kfree(set->srcu); 4962 } 4963 } 4964 EXPORT_SYMBOL(blk_mq_free_tag_set); 4965 4966 struct elevator_tags *blk_mq_update_nr_requests(struct request_queue *q, 4967 struct elevator_tags *et, 4968 unsigned int nr) 4969 { 4970 struct blk_mq_tag_set *set = q->tag_set; 4971 struct elevator_tags *old_et = NULL; 4972 struct blk_mq_hw_ctx *hctx; 4973 unsigned long i; 4974 4975 blk_mq_quiesce_queue(q); 4976 4977 if (blk_mq_is_shared_tags(set->flags)) { 4978 /* 4979 * Shared tags, for sched tags, we allocate max initially hence 4980 * tags can't grow, see blk_mq_alloc_sched_tags(). 4981 */ 4982 if (q->elevator) 4983 blk_mq_tag_update_sched_shared_tags(q, nr); 4984 else 4985 blk_mq_tag_resize_shared_tags(set, nr); 4986 } else if (!q->elevator) { 4987 /* 4988 * Non-shared hardware tags, nr is already checked from 4989 * queue_requests_store() and tags can't grow. 4990 */ 4991 queue_for_each_hw_ctx(q, hctx, i) { 4992 if (!hctx->tags) 4993 continue; 4994 sbitmap_queue_resize(&hctx->tags->bitmap_tags, 4995 nr - hctx->tags->nr_reserved_tags); 4996 } 4997 } else if (nr <= q->elevator->et->nr_requests) { 4998 /* Non-shared sched tags, and tags don't grow. */ 4999 queue_for_each_hw_ctx(q, hctx, i) { 5000 if (!hctx->sched_tags) 5001 continue; 5002 sbitmap_queue_resize(&hctx->sched_tags->bitmap_tags, 5003 nr - hctx->sched_tags->nr_reserved_tags); 5004 } 5005 } else { 5006 /* Non-shared sched tags, and tags grow */ 5007 queue_for_each_hw_ctx(q, hctx, i) 5008 hctx->sched_tags = et->tags[i]; 5009 old_et = q->elevator->et; 5010 q->elevator->et = et; 5011 } 5012 5013 q->nr_requests = nr; 5014 if (q->elevator && q->elevator->type->ops.depth_updated) 5015 q->elevator->type->ops.depth_updated(q); 5016 5017 blk_mq_unquiesce_queue(q); 5018 return old_et; 5019 } 5020 5021 /* 5022 * Switch back to the elevator type stored in the xarray. 5023 */ 5024 static void blk_mq_elv_switch_back(struct request_queue *q, 5025 struct xarray *elv_tbl) 5026 { 5027 struct elv_change_ctx *ctx = xa_load(elv_tbl, q->id); 5028 5029 if (WARN_ON_ONCE(!ctx)) 5030 return; 5031 5032 /* The elv_update_nr_hw_queues unfreezes the queue. */ 5033 elv_update_nr_hw_queues(q, ctx); 5034 5035 /* Drop the reference acquired in blk_mq_elv_switch_none. */ 5036 if (ctx->type) 5037 elevator_put(ctx->type); 5038 } 5039 5040 /* 5041 * Stores elevator name and type in ctx and set current elevator to none. 5042 */ 5043 static int blk_mq_elv_switch_none(struct request_queue *q, 5044 struct xarray *elv_tbl) 5045 { 5046 struct elv_change_ctx *ctx; 5047 5048 lockdep_assert_held_write(&q->tag_set->update_nr_hwq_lock); 5049 5050 /* 5051 * Accessing q->elevator without holding q->elevator_lock is safe here 5052 * because we're called from nr_hw_queue update which is protected by 5053 * set->update_nr_hwq_lock in the writer context. So, scheduler update/ 5054 * switch code (which acquires the same lock in the reader context) 5055 * can't run concurrently. 5056 */ 5057 if (q->elevator) { 5058 ctx = xa_load(elv_tbl, q->id); 5059 if (WARN_ON_ONCE(!ctx)) 5060 return -ENOENT; 5061 5062 ctx->name = q->elevator->type->elevator_name; 5063 5064 /* 5065 * Before we switch elevator to 'none', take a reference to 5066 * the elevator module so that while nr_hw_queue update is 5067 * running, no one can remove elevator module. We'd put the 5068 * reference to elevator module later when we switch back 5069 * elevator. 5070 */ 5071 __elevator_get(q->elevator->type); 5072 5073 /* 5074 * Store elevator type so that we can release the reference 5075 * taken above later. 5076 */ 5077 ctx->type = q->elevator->type; 5078 elevator_set_none(q); 5079 } 5080 return 0; 5081 } 5082 5083 static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, 5084 int nr_hw_queues) 5085 { 5086 struct request_queue *q; 5087 int prev_nr_hw_queues = set->nr_hw_queues; 5088 unsigned int memflags; 5089 int i; 5090 struct xarray elv_tbl; 5091 struct blk_mq_tags **new_tags; 5092 bool queues_frozen = false; 5093 5094 lockdep_assert_held(&set->tag_list_lock); 5095 5096 if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids) 5097 nr_hw_queues = nr_cpu_ids; 5098 if (nr_hw_queues < 1) 5099 return; 5100 if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues) 5101 return; 5102 5103 memflags = memalloc_noio_save(); 5104 5105 xa_init(&elv_tbl); 5106 if (blk_mq_alloc_sched_ctx_batch(&elv_tbl, set) < 0) 5107 goto out_free_ctx; 5108 5109 if (blk_mq_alloc_sched_res_batch(&elv_tbl, set, nr_hw_queues) < 0) 5110 goto out_free_ctx; 5111 5112 list_for_each_entry(q, &set->tag_list, tag_set_list) { 5113 blk_mq_debugfs_unregister_hctxs(q); 5114 blk_mq_sysfs_unregister_hctxs(q); 5115 } 5116 5117 /* 5118 * Switch IO scheduler to 'none', cleaning up the data associated 5119 * with the previous scheduler. We will switch back once we are done 5120 * updating the new sw to hw queue mappings. 5121 */ 5122 list_for_each_entry(q, &set->tag_list, tag_set_list) 5123 if (blk_mq_elv_switch_none(q, &elv_tbl)) 5124 goto switch_back; 5125 5126 new_tags = blk_mq_prealloc_tag_set_tags(set, nr_hw_queues); 5127 if (IS_ERR(new_tags)) 5128 goto switch_back; 5129 5130 list_for_each_entry(q, &set->tag_list, tag_set_list) 5131 blk_mq_freeze_queue_nomemsave(q); 5132 queues_frozen = true; 5133 if (new_tags) { 5134 kfree(set->tags); 5135 set->tags = new_tags; 5136 } 5137 set->nr_hw_queues = nr_hw_queues; 5138 5139 fallback: 5140 blk_mq_update_queue_map(set); 5141 list_for_each_entry(q, &set->tag_list, tag_set_list) { 5142 __blk_mq_realloc_hw_ctxs(set, q); 5143 5144 if (q->nr_hw_queues != set->nr_hw_queues) { 5145 int i = prev_nr_hw_queues; 5146 5147 pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n", 5148 nr_hw_queues, prev_nr_hw_queues); 5149 for (; i < set->nr_hw_queues; i++) 5150 __blk_mq_free_map_and_rqs(set, i); 5151 5152 set->nr_hw_queues = prev_nr_hw_queues; 5153 goto fallback; 5154 } 5155 blk_mq_map_swqueue(q); 5156 } 5157 switch_back: 5158 /* The blk_mq_elv_switch_back unfreezes queue for us. */ 5159 list_for_each_entry(q, &set->tag_list, tag_set_list) { 5160 /* switch_back expects queue to be frozen */ 5161 if (!queues_frozen) 5162 blk_mq_freeze_queue_nomemsave(q); 5163 blk_mq_elv_switch_back(q, &elv_tbl); 5164 } 5165 5166 list_for_each_entry(q, &set->tag_list, tag_set_list) { 5167 blk_mq_sysfs_register_hctxs(q); 5168 blk_mq_debugfs_register_hctxs(q); 5169 5170 blk_mq_remove_hw_queues_cpuhp(q); 5171 blk_mq_add_hw_queues_cpuhp(q); 5172 } 5173 5174 out_free_ctx: 5175 blk_mq_free_sched_ctx_batch(&elv_tbl); 5176 xa_destroy(&elv_tbl); 5177 memalloc_noio_restore(memflags); 5178 5179 /* Free the excess tags when nr_hw_queues shrink. */ 5180 for (i = set->nr_hw_queues; i < prev_nr_hw_queues; i++) 5181 __blk_mq_free_map_and_rqs(set, i); 5182 } 5183 5184 void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) 5185 { 5186 down_write(&set->update_nr_hwq_lock); 5187 mutex_lock(&set->tag_list_lock); 5188 __blk_mq_update_nr_hw_queues(set, nr_hw_queues); 5189 mutex_unlock(&set->tag_list_lock); 5190 up_write(&set->update_nr_hwq_lock); 5191 } 5192 EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); 5193 5194 static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx, 5195 struct io_comp_batch *iob, unsigned int flags) 5196 { 5197 long state = get_current_state(); 5198 int ret; 5199 5200 do { 5201 ret = q->mq_ops->poll(hctx, iob); 5202 if (ret > 0) { 5203 __set_current_state(TASK_RUNNING); 5204 return ret; 5205 } 5206 5207 if (signal_pending_state(state, current)) 5208 __set_current_state(TASK_RUNNING); 5209 if (task_is_running(current)) 5210 return 1; 5211 5212 if (ret < 0 || (flags & BLK_POLL_ONESHOT)) 5213 break; 5214 cpu_relax(); 5215 } while (!need_resched()); 5216 5217 __set_current_state(TASK_RUNNING); 5218 return 0; 5219 } 5220 5221 int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, 5222 struct io_comp_batch *iob, unsigned int flags) 5223 { 5224 if (!blk_mq_can_poll(q)) 5225 return 0; 5226 return blk_hctx_poll(q, xa_load(&q->hctx_table, cookie), iob, flags); 5227 } 5228 5229 int blk_rq_poll(struct request *rq, struct io_comp_batch *iob, 5230 unsigned int poll_flags) 5231 { 5232 struct request_queue *q = rq->q; 5233 int ret; 5234 5235 if (!blk_rq_is_poll(rq)) 5236 return 0; 5237 if (!percpu_ref_tryget(&q->q_usage_counter)) 5238 return 0; 5239 5240 ret = blk_hctx_poll(q, rq->mq_hctx, iob, poll_flags); 5241 blk_queue_exit(q); 5242 5243 return ret; 5244 } 5245 EXPORT_SYMBOL_GPL(blk_rq_poll); 5246 5247 unsigned int blk_mq_rq_cpu(struct request *rq) 5248 { 5249 return rq->mq_ctx->cpu; 5250 } 5251 EXPORT_SYMBOL(blk_mq_rq_cpu); 5252 5253 void blk_mq_cancel_work_sync(struct request_queue *q) 5254 { 5255 struct blk_mq_hw_ctx *hctx; 5256 unsigned long i; 5257 5258 cancel_delayed_work_sync(&q->requeue_work); 5259 5260 queue_for_each_hw_ctx(q, hctx, i) 5261 cancel_delayed_work_sync(&hctx->run_work); 5262 } 5263 5264 static int __init blk_mq_init(void) 5265 { 5266 int i; 5267 5268 for_each_possible_cpu(i) 5269 init_llist_head(&per_cpu(blk_cpu_done, i)); 5270 for_each_possible_cpu(i) 5271 INIT_CSD(&per_cpu(blk_cpu_csd, i), 5272 __blk_mq_complete_request_remote, NULL); 5273 open_softirq(BLOCK_SOFTIRQ, blk_done_softirq); 5274 5275 cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD, 5276 "block/softirq:dead", NULL, 5277 blk_softirq_cpu_dead); 5278 cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, 5279 blk_mq_hctx_notify_dead); 5280 cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online", 5281 blk_mq_hctx_notify_online, 5282 blk_mq_hctx_notify_offline); 5283 return 0; 5284 } 5285 subsys_initcall(blk_mq_init);