1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * Copyright (C) 1994, Karl Keyte: Added support for disk statistics 5 * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE 6 * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> 7 * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> 8 * - July2000 9 * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 10 */ 11 12 /* 13 * This handles all read/write requests to block devices 14 */ 15 #include <linux/kernel.h> 16 #include <linux/module.h> 17 #include <linux/backing-dev.h> 18 #include <linux/bio.h> 19 #include <linux/blkdev.h> 20 #include <linux/blk-mq.h> 21 #include <linux/highmem.h> 22 #include <linux/mm.h> 23 #include <linux/kernel_stat.h> 24 #include <linux/string.h> 25 #include <linux/init.h> 26 #include <linux/completion.h> 27 #include <linux/slab.h> 28 #include <linux/swap.h> 29 #include <linux/writeback.h> 30 #include <linux/task_io_accounting_ops.h> 31 #include <linux/fault-inject.h> 32 #include <linux/list_sort.h> 33 #include <linux/delay.h> 34 #include <linux/ratelimit.h> 35 #include <linux/pm_runtime.h> 36 #include <linux/blk-cgroup.h> 37 #include <linux/debugfs.h> 38 #include <linux/bpf.h> 39 40 #define CREATE_TRACE_POINTS 41 #include <trace/events/block.h> 42 43 #include "blk.h" 44 #include "blk-mq.h" 45 #include "blk-mq-sched.h" 46 #include "blk-pm.h" 47 #include "blk-rq-qos.h" 48 49 #ifdef CONFIG_DEBUG_FS 50 struct dentry *blk_debugfs_root; 51 #endif 52 53 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); 54 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); 55 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); 56 EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); 57 EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); 58 59 DEFINE_IDA(blk_queue_ida); 60 61 /* 62 * For queue allocation 63 */ 64 struct kmem_cache *blk_requestq_cachep; 65 66 /* 67 * Controlling structure to kblockd 68 */ 69 static struct workqueue_struct *kblockd_workqueue; 70 71 /** 72 * blk_queue_flag_set - atomically set a queue flag 73 * @flag: flag to be set 74 * @q: request queue 75 */ 76 void blk_queue_flag_set(unsigned int flag, struct request_queue *q) 77 { 78 set_bit(flag, &q->queue_flags); 79 } 80 EXPORT_SYMBOL(blk_queue_flag_set); 81 82 /** 83 * blk_queue_flag_clear - atomically clear a queue flag 84 * @flag: flag to be cleared 85 * @q: request queue 86 */ 87 void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) 88 { 89 clear_bit(flag, &q->queue_flags); 90 } 91 EXPORT_SYMBOL(blk_queue_flag_clear); 92 93 /** 94 * blk_queue_flag_test_and_set - atomically test and set a queue flag 95 * @flag: flag to be set 96 * @q: request queue 97 * 98 * Returns the previous value of @flag - 0 if the flag was not set and 1 if 99 * the flag was already set. 100 */ 101 bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) 102 { 103 return test_and_set_bit(flag, &q->queue_flags); 104 } 105 EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); 106 107 void blk_rq_init(struct request_queue *q, struct request *rq) 108 { 109 memset(rq, 0, sizeof(*rq)); 110 111 INIT_LIST_HEAD(&rq->queuelist); 112 rq->q = q; 113 rq->__sector = (sector_t) -1; 114 INIT_HLIST_NODE(&rq->hash); 115 RB_CLEAR_NODE(&rq->rb_node); 116 rq->tag = -1; 117 rq->internal_tag = -1; 118 rq->start_time_ns = ktime_get_ns(); 119 rq->part = NULL; 120 } 121 EXPORT_SYMBOL(blk_rq_init); 122 123 static const struct { 124 int errno; 125 const char *name; 126 } blk_errors[] = { 127 [BLK_STS_OK] = { 0, "" }, 128 [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, 129 [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, 130 [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, 131 [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, 132 [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, 133 [BLK_STS_NEXUS] = { -EBADE, "critical nexus" }, 134 [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, 135 [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, 136 [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, 137 [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" }, 138 [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, 139 140 /* device mapper special case, should not leak out: */ 141 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, 142 143 /* everything else not covered above: */ 144 [BLK_STS_IOERR] = { -EIO, "I/O" }, 145 }; 146 147 blk_status_t errno_to_blk_status(int errno) 148 { 149 int i; 150 151 for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { 152 if (blk_errors[i].errno == errno) 153 return (__force blk_status_t)i; 154 } 155 156 return BLK_STS_IOERR; 157 } 158 EXPORT_SYMBOL_GPL(errno_to_blk_status); 159 160 int blk_status_to_errno(blk_status_t status) 161 { 162 int idx = (__force int)status; 163 164 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) 165 return -EIO; 166 return blk_errors[idx].errno; 167 } 168 EXPORT_SYMBOL_GPL(blk_status_to_errno); 169 170 static void print_req_error(struct request *req, blk_status_t status) 171 { 172 int idx = (__force int)status; 173 174 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) 175 return; 176 177 printk_ratelimited(KERN_ERR "%s: %s error, dev %s, sector %llu flags %x\n", 178 __func__, blk_errors[idx].name, 179 req->rq_disk ? req->rq_disk->disk_name : "?", 180 (unsigned long long)blk_rq_pos(req), 181 req->cmd_flags); 182 } 183 184 static void req_bio_endio(struct request *rq, struct bio *bio, 185 unsigned int nbytes, blk_status_t error) 186 { 187 if (error) 188 bio->bi_status = error; 189 190 if (unlikely(rq->rq_flags & RQF_QUIET)) 191 bio_set_flag(bio, BIO_QUIET); 192 193 bio_advance(bio, nbytes); 194 195 /* don't actually finish bio if it's part of flush sequence */ 196 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) 197 bio_endio(bio); 198 } 199 200 void blk_dump_rq_flags(struct request *rq, char *msg) 201 { 202 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg, 203 rq->rq_disk ? rq->rq_disk->disk_name : "?", 204 (unsigned long long) rq->cmd_flags); 205 206 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", 207 (unsigned long long)blk_rq_pos(rq), 208 blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); 209 printk(KERN_INFO " bio %p, biotail %p, len %u\n", 210 rq->bio, rq->biotail, blk_rq_bytes(rq)); 211 } 212 EXPORT_SYMBOL(blk_dump_rq_flags); 213 214 /** 215 * blk_sync_queue - cancel any pending callbacks on a queue 216 * @q: the queue 217 * 218 * Description: 219 * The block layer may perform asynchronous callback activity 220 * on a queue, such as calling the unplug function after a timeout. 221 * A block device may call blk_sync_queue to ensure that any 222 * such activity is cancelled, thus allowing it to release resources 223 * that the callbacks might use. The caller must already have made sure 224 * that its ->make_request_fn will not re-add plugging prior to calling 225 * this function. 226 * 227 * This function does not cancel any asynchronous activity arising 228 * out of elevator or throttling code. That would require elevator_exit() 229 * and blkcg_exit_queue() to be called with queue lock initialized. 230 * 231 */ 232 void blk_sync_queue(struct request_queue *q) 233 { 234 del_timer_sync(&q->timeout); 235 cancel_work_sync(&q->timeout_work); 236 } 237 EXPORT_SYMBOL(blk_sync_queue); 238 239 /** 240 * blk_set_pm_only - increment pm_only counter 241 * @q: request queue pointer 242 */ 243 void blk_set_pm_only(struct request_queue *q) 244 { 245 atomic_inc(&q->pm_only); 246 } 247 EXPORT_SYMBOL_GPL(blk_set_pm_only); 248 249 void blk_clear_pm_only(struct request_queue *q) 250 { 251 int pm_only; 252 253 pm_only = atomic_dec_return(&q->pm_only); 254 WARN_ON_ONCE(pm_only < 0); 255 if (pm_only == 0) 256 wake_up_all(&q->mq_freeze_wq); 257 } 258 EXPORT_SYMBOL_GPL(blk_clear_pm_only); 259 260 void blk_put_queue(struct request_queue *q) 261 { 262 kobject_put(&q->kobj); 263 } 264 EXPORT_SYMBOL(blk_put_queue); 265 266 void blk_set_queue_dying(struct request_queue *q) 267 { 268 blk_queue_flag_set(QUEUE_FLAG_DYING, q); 269 270 /* 271 * When queue DYING flag is set, we need to block new req 272 * entering queue, so we call blk_freeze_queue_start() to 273 * prevent I/O from crossing blk_queue_enter(). 274 */ 275 blk_freeze_queue_start(q); 276 277 if (queue_is_mq(q)) 278 blk_mq_wake_waiters(q); 279 280 /* Make blk_queue_enter() reexamine the DYING flag. */ 281 wake_up_all(&q->mq_freeze_wq); 282 } 283 EXPORT_SYMBOL_GPL(blk_set_queue_dying); 284 285 /** 286 * blk_cleanup_queue - shutdown a request queue 287 * @q: request queue to shutdown 288 * 289 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and 290 * put it. All future requests will be failed immediately with -ENODEV. 291 */ 292 void blk_cleanup_queue(struct request_queue *q) 293 { 294 /* mark @q DYING, no new request or merges will be allowed afterwards */ 295 mutex_lock(&q->sysfs_lock); 296 blk_set_queue_dying(q); 297 298 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); 299 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); 300 blk_queue_flag_set(QUEUE_FLAG_DYING, q); 301 mutex_unlock(&q->sysfs_lock); 302 303 /* 304 * Drain all requests queued before DYING marking. Set DEAD flag to 305 * prevent that q->request_fn() gets invoked after draining finished. 306 */ 307 blk_freeze_queue(q); 308 309 rq_qos_exit(q); 310 311 blk_queue_flag_set(QUEUE_FLAG_DEAD, q); 312 313 /* for synchronous bio-based driver finish in-flight integrity i/o */ 314 blk_flush_integrity(); 315 316 /* @q won't process any more request, flush async actions */ 317 del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer); 318 blk_sync_queue(q); 319 320 if (queue_is_mq(q)) 321 blk_mq_exit_queue(q); 322 323 percpu_ref_exit(&q->q_usage_counter); 324 325 /* @q is and will stay empty, shutdown and put */ 326 blk_put_queue(q); 327 } 328 EXPORT_SYMBOL(blk_cleanup_queue); 329 330 struct request_queue *blk_alloc_queue(gfp_t gfp_mask) 331 { 332 return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE); 333 } 334 EXPORT_SYMBOL(blk_alloc_queue); 335 336 /** 337 * blk_queue_enter() - try to increase q->q_usage_counter 338 * @q: request queue pointer 339 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PREEMPT 340 */ 341 int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) 342 { 343 const bool pm = flags & BLK_MQ_REQ_PREEMPT; 344 345 while (true) { 346 bool success = false; 347 348 rcu_read_lock(); 349 if (percpu_ref_tryget_live(&q->q_usage_counter)) { 350 /* 351 * The code that increments the pm_only counter is 352 * responsible for ensuring that that counter is 353 * globally visible before the queue is unfrozen. 354 */ 355 if (pm || !blk_queue_pm_only(q)) { 356 success = true; 357 } else { 358 percpu_ref_put(&q->q_usage_counter); 359 } 360 } 361 rcu_read_unlock(); 362 363 if (success) 364 return 0; 365 366 if (flags & BLK_MQ_REQ_NOWAIT) 367 return -EBUSY; 368 369 /* 370 * read pair of barrier in blk_freeze_queue_start(), 371 * we need to order reading __PERCPU_REF_DEAD flag of 372 * .q_usage_counter and reading .mq_freeze_depth or 373 * queue dying flag, otherwise the following wait may 374 * never return if the two reads are reordered. 375 */ 376 smp_rmb(); 377 378 wait_event(q->mq_freeze_wq, 379 (!q->mq_freeze_depth && 380 (pm || (blk_pm_request_resume(q), 381 !blk_queue_pm_only(q)))) || 382 blk_queue_dying(q)); 383 if (blk_queue_dying(q)) 384 return -ENODEV; 385 } 386 } 387 388 void blk_queue_exit(struct request_queue *q) 389 { 390 percpu_ref_put(&q->q_usage_counter); 391 } 392 393 static void blk_queue_usage_counter_release(struct percpu_ref *ref) 394 { 395 struct request_queue *q = 396 container_of(ref, struct request_queue, q_usage_counter); 397 398 wake_up_all(&q->mq_freeze_wq); 399 } 400 401 static void blk_rq_timed_out_timer(struct timer_list *t) 402 { 403 struct request_queue *q = from_timer(q, t, timeout); 404 405 kblockd_schedule_work(&q->timeout_work); 406 } 407 408 static void blk_timeout_work(struct work_struct *work) 409 { 410 } 411 412 /** 413 * blk_alloc_queue_node - allocate a request queue 414 * @gfp_mask: memory allocation flags 415 * @node_id: NUMA node to allocate memory from 416 */ 417 struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) 418 { 419 struct request_queue *q; 420 int ret; 421 422 q = kmem_cache_alloc_node(blk_requestq_cachep, 423 gfp_mask | __GFP_ZERO, node_id); 424 if (!q) 425 return NULL; 426 427 INIT_LIST_HEAD(&q->queue_head); 428 q->last_merge = NULL; 429 430 q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); 431 if (q->id < 0) 432 goto fail_q; 433 434 ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); 435 if (ret) 436 goto fail_id; 437 438 q->backing_dev_info = bdi_alloc_node(gfp_mask, node_id); 439 if (!q->backing_dev_info) 440 goto fail_split; 441 442 q->stats = blk_alloc_queue_stats(); 443 if (!q->stats) 444 goto fail_stats; 445 446 q->backing_dev_info->ra_pages = VM_READAHEAD_PAGES; 447 q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK; 448 q->backing_dev_info->name = "block"; 449 q->node = node_id; 450 451 timer_setup(&q->backing_dev_info->laptop_mode_wb_timer, 452 laptop_mode_timer_fn, 0); 453 timer_setup(&q->timeout, blk_rq_timed_out_timer, 0); 454 INIT_WORK(&q->timeout_work, blk_timeout_work); 455 INIT_LIST_HEAD(&q->icq_list); 456 #ifdef CONFIG_BLK_CGROUP 457 INIT_LIST_HEAD(&q->blkg_list); 458 #endif 459 460 kobject_init(&q->kobj, &blk_queue_ktype); 461 462 #ifdef CONFIG_BLK_DEV_IO_TRACE 463 mutex_init(&q->blk_trace_mutex); 464 #endif 465 mutex_init(&q->sysfs_lock); 466 spin_lock_init(&q->queue_lock); 467 468 init_waitqueue_head(&q->mq_freeze_wq); 469 mutex_init(&q->mq_freeze_lock); 470 471 /* 472 * Init percpu_ref in atomic mode so that it's faster to shutdown. 473 * See blk_register_queue() for details. 474 */ 475 if (percpu_ref_init(&q->q_usage_counter, 476 blk_queue_usage_counter_release, 477 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) 478 goto fail_bdi; 479 480 if (blkcg_init_queue(q)) 481 goto fail_ref; 482 483 return q; 484 485 fail_ref: 486 percpu_ref_exit(&q->q_usage_counter); 487 fail_bdi: 488 blk_free_queue_stats(q->stats); 489 fail_stats: 490 bdi_put(q->backing_dev_info); 491 fail_split: 492 bioset_exit(&q->bio_split); 493 fail_id: 494 ida_simple_remove(&blk_queue_ida, q->id); 495 fail_q: 496 kmem_cache_free(blk_requestq_cachep, q); 497 return NULL; 498 } 499 EXPORT_SYMBOL(blk_alloc_queue_node); 500 501 bool blk_get_queue(struct request_queue *q) 502 { 503 if (likely(!blk_queue_dying(q))) { 504 __blk_get_queue(q); 505 return true; 506 } 507 508 return false; 509 } 510 EXPORT_SYMBOL(blk_get_queue); 511 512 /** 513 * blk_get_request - allocate a request 514 * @q: request queue to allocate a request for 515 * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC. 516 * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT. 517 */ 518 struct request *blk_get_request(struct request_queue *q, unsigned int op, 519 blk_mq_req_flags_t flags) 520 { 521 struct request *req; 522 523 WARN_ON_ONCE(op & REQ_NOWAIT); 524 WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PREEMPT)); 525 526 req = blk_mq_alloc_request(q, op, flags); 527 if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn) 528 q->mq_ops->initialize_rq_fn(req); 529 530 return req; 531 } 532 EXPORT_SYMBOL(blk_get_request); 533 534 void blk_put_request(struct request *req) 535 { 536 blk_mq_free_request(req); 537 } 538 EXPORT_SYMBOL(blk_put_request); 539 540 bool bio_attempt_back_merge(struct request_queue *q, struct request *req, 541 struct bio *bio) 542 { 543 const int ff = bio->bi_opf & REQ_FAILFAST_MASK; 544 545 if (!ll_back_merge_fn(q, req, bio)) 546 return false; 547 548 trace_block_bio_backmerge(q, req, bio); 549 550 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) 551 blk_rq_set_mixed_merge(req); 552 553 req->biotail->bi_next = bio; 554 req->biotail = bio; 555 req->__data_len += bio->bi_iter.bi_size; 556 557 blk_account_io_start(req, false); 558 return true; 559 } 560 561 bool bio_attempt_front_merge(struct request_queue *q, struct request *req, 562 struct bio *bio) 563 { 564 const int ff = bio->bi_opf & REQ_FAILFAST_MASK; 565 566 if (!ll_front_merge_fn(q, req, bio)) 567 return false; 568 569 trace_block_bio_frontmerge(q, req, bio); 570 571 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) 572 blk_rq_set_mixed_merge(req); 573 574 bio->bi_next = req->bio; 575 req->bio = bio; 576 577 req->__sector = bio->bi_iter.bi_sector; 578 req->__data_len += bio->bi_iter.bi_size; 579 580 blk_account_io_start(req, false); 581 return true; 582 } 583 584 bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, 585 struct bio *bio) 586 { 587 unsigned short segments = blk_rq_nr_discard_segments(req); 588 589 if (segments >= queue_max_discard_segments(q)) 590 goto no_merge; 591 if (blk_rq_sectors(req) + bio_sectors(bio) > 592 blk_rq_get_max_sectors(req, blk_rq_pos(req))) 593 goto no_merge; 594 595 req->biotail->bi_next = bio; 596 req->biotail = bio; 597 req->__data_len += bio->bi_iter.bi_size; 598 req->nr_phys_segments = segments + 1; 599 600 blk_account_io_start(req, false); 601 return true; 602 no_merge: 603 req_set_nomerge(q, req); 604 return false; 605 } 606 607 /** 608 * blk_attempt_plug_merge - try to merge with %current's plugged list 609 * @q: request_queue new bio is being queued at 610 * @bio: new bio being queued 611 * @same_queue_rq: pointer to &struct request that gets filled in when 612 * another request associated with @q is found on the plug list 613 * (optional, may be %NULL) 614 * 615 * Determine whether @bio being queued on @q can be merged with a request 616 * on %current's plugged list. Returns %true if merge was successful, 617 * otherwise %false. 618 * 619 * Plugging coalesces IOs from the same issuer for the same purpose without 620 * going through @q->queue_lock. As such it's more of an issuing mechanism 621 * than scheduling, and the request, while may have elvpriv data, is not 622 * added on the elevator at this point. In addition, we don't have 623 * reliable access to the elevator outside queue lock. Only check basic 624 * merging parameters without querying the elevator. 625 * 626 * Caller must ensure !blk_queue_nomerges(q) beforehand. 627 */ 628 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, 629 struct request **same_queue_rq) 630 { 631 struct blk_plug *plug; 632 struct request *rq; 633 struct list_head *plug_list; 634 635 plug = current->plug; 636 if (!plug) 637 return false; 638 639 plug_list = &plug->mq_list; 640 641 list_for_each_entry_reverse(rq, plug_list, queuelist) { 642 bool merged = false; 643 644 if (rq->q == q && same_queue_rq) { 645 /* 646 * Only blk-mq multiple hardware queues case checks the 647 * rq in the same queue, there should be only one such 648 * rq in a queue 649 **/ 650 *same_queue_rq = rq; 651 } 652 653 if (rq->q != q || !blk_rq_merge_ok(rq, bio)) 654 continue; 655 656 switch (blk_try_merge(rq, bio)) { 657 case ELEVATOR_BACK_MERGE: 658 merged = bio_attempt_back_merge(q, rq, bio); 659 break; 660 case ELEVATOR_FRONT_MERGE: 661 merged = bio_attempt_front_merge(q, rq, bio); 662 break; 663 case ELEVATOR_DISCARD_MERGE: 664 merged = bio_attempt_discard_merge(q, rq, bio); 665 break; 666 default: 667 break; 668 } 669 670 if (merged) 671 return true; 672 } 673 674 return false; 675 } 676 677 void blk_init_request_from_bio(struct request *req, struct bio *bio) 678 { 679 if (bio->bi_opf & REQ_RAHEAD) 680 req->cmd_flags |= REQ_FAILFAST_MASK; 681 682 req->__sector = bio->bi_iter.bi_sector; 683 req->ioprio = bio_prio(bio); 684 req->write_hint = bio->bi_write_hint; 685 blk_rq_bio_prep(req->q, req, bio); 686 } 687 EXPORT_SYMBOL_GPL(blk_init_request_from_bio); 688 689 static void handle_bad_sector(struct bio *bio, sector_t maxsector) 690 { 691 char b[BDEVNAME_SIZE]; 692 693 printk(KERN_INFO "attempt to access beyond end of device\n"); 694 printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n", 695 bio_devname(bio, b), bio->bi_opf, 696 (unsigned long long)bio_end_sector(bio), 697 (long long)maxsector); 698 } 699 700 #ifdef CONFIG_FAIL_MAKE_REQUEST 701 702 static DECLARE_FAULT_ATTR(fail_make_request); 703 704 static int __init setup_fail_make_request(char *str) 705 { 706 return setup_fault_attr(&fail_make_request, str); 707 } 708 __setup("fail_make_request=", setup_fail_make_request); 709 710 static bool should_fail_request(struct hd_struct *part, unsigned int bytes) 711 { 712 return part->make_it_fail && should_fail(&fail_make_request, bytes); 713 } 714 715 static int __init fail_make_request_debugfs(void) 716 { 717 struct dentry *dir = fault_create_debugfs_attr("fail_make_request", 718 NULL, &fail_make_request); 719 720 return PTR_ERR_OR_ZERO(dir); 721 } 722 723 late_initcall(fail_make_request_debugfs); 724 725 #else /* CONFIG_FAIL_MAKE_REQUEST */ 726 727 static inline bool should_fail_request(struct hd_struct *part, 728 unsigned int bytes) 729 { 730 return false; 731 } 732 733 #endif /* CONFIG_FAIL_MAKE_REQUEST */ 734 735 static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part) 736 { 737 const int op = bio_op(bio); 738 739 if (part->policy && op_is_write(op)) { 740 char b[BDEVNAME_SIZE]; 741 742 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) 743 return false; 744 745 WARN_ONCE(1, 746 "generic_make_request: Trying to write " 747 "to read-only block-device %s (partno %d)\n", 748 bio_devname(bio, b), part->partno); 749 /* Older lvm-tools actually trigger this */ 750 return false; 751 } 752 753 return false; 754 } 755 756 static noinline int should_fail_bio(struct bio *bio) 757 { 758 if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size)) 759 return -EIO; 760 return 0; 761 } 762 ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); 763 764 /* 765 * Check whether this bio extends beyond the end of the device or partition. 766 * This may well happen - the kernel calls bread() without checking the size of 767 * the device, e.g., when mounting a file system. 768 */ 769 static inline int bio_check_eod(struct bio *bio, sector_t maxsector) 770 { 771 unsigned int nr_sectors = bio_sectors(bio); 772 773 if (nr_sectors && maxsector && 774 (nr_sectors > maxsector || 775 bio->bi_iter.bi_sector > maxsector - nr_sectors)) { 776 handle_bad_sector(bio, maxsector); 777 return -EIO; 778 } 779 return 0; 780 } 781 782 /* 783 * Remap block n of partition p to block n+start(p) of the disk. 784 */ 785 static inline int blk_partition_remap(struct bio *bio) 786 { 787 struct hd_struct *p; 788 int ret = -EIO; 789 790 rcu_read_lock(); 791 p = __disk_get_part(bio->bi_disk, bio->bi_partno); 792 if (unlikely(!p)) 793 goto out; 794 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) 795 goto out; 796 if (unlikely(bio_check_ro(bio, p))) 797 goto out; 798 799 /* 800 * Zone reset does not include bi_size so bio_sectors() is always 0. 801 * Include a test for the reset op code and perform the remap if needed. 802 */ 803 if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET) { 804 if (bio_check_eod(bio, part_nr_sects_read(p))) 805 goto out; 806 bio->bi_iter.bi_sector += p->start_sect; 807 trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), 808 bio->bi_iter.bi_sector - p->start_sect); 809 } 810 bio->bi_partno = 0; 811 ret = 0; 812 out: 813 rcu_read_unlock(); 814 return ret; 815 } 816 817 static noinline_for_stack bool 818 generic_make_request_checks(struct bio *bio) 819 { 820 struct request_queue *q; 821 int nr_sectors = bio_sectors(bio); 822 blk_status_t status = BLK_STS_IOERR; 823 char b[BDEVNAME_SIZE]; 824 825 might_sleep(); 826 827 q = bio->bi_disk->queue; 828 if (unlikely(!q)) { 829 printk(KERN_ERR 830 "generic_make_request: Trying to access " 831 "nonexistent block-device %s (%Lu)\n", 832 bio_devname(bio, b), (long long)bio->bi_iter.bi_sector); 833 goto end_io; 834 } 835 836 /* 837 * For a REQ_NOWAIT based request, return -EOPNOTSUPP 838 * if queue is not a request based queue. 839 */ 840 if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q)) 841 goto not_supported; 842 843 if (should_fail_bio(bio)) 844 goto end_io; 845 846 if (bio->bi_partno) { 847 if (unlikely(blk_partition_remap(bio))) 848 goto end_io; 849 } else { 850 if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0))) 851 goto end_io; 852 if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk)))) 853 goto end_io; 854 } 855 856 /* 857 * Filter flush bio's early so that make_request based 858 * drivers without flush support don't have to worry 859 * about them. 860 */ 861 if (op_is_flush(bio->bi_opf) && 862 !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { 863 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); 864 if (!nr_sectors) { 865 status = BLK_STS_OK; 866 goto end_io; 867 } 868 } 869 870 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) 871 bio->bi_opf &= ~REQ_HIPRI; 872 873 switch (bio_op(bio)) { 874 case REQ_OP_DISCARD: 875 if (!blk_queue_discard(q)) 876 goto not_supported; 877 break; 878 case REQ_OP_SECURE_ERASE: 879 if (!blk_queue_secure_erase(q)) 880 goto not_supported; 881 break; 882 case REQ_OP_WRITE_SAME: 883 if (!q->limits.max_write_same_sectors) 884 goto not_supported; 885 break; 886 case REQ_OP_ZONE_RESET: 887 if (!blk_queue_is_zoned(q)) 888 goto not_supported; 889 break; 890 case REQ_OP_WRITE_ZEROES: 891 if (!q->limits.max_write_zeroes_sectors) 892 goto not_supported; 893 break; 894 default: 895 break; 896 } 897 898 /* 899 * Various block parts want %current->io_context and lazy ioc 900 * allocation ends up trading a lot of pain for a small amount of 901 * memory. Just allocate it upfront. This may fail and block 902 * layer knows how to live with it. 903 */ 904 create_io_context(GFP_ATOMIC, q->node); 905 906 if (!blkcg_bio_issue_check(q, bio)) 907 return false; 908 909 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { 910 trace_block_bio_queue(q, bio); 911 /* Now that enqueuing has been traced, we need to trace 912 * completion as well. 913 */ 914 bio_set_flag(bio, BIO_TRACE_COMPLETION); 915 } 916 return true; 917 918 not_supported: 919 status = BLK_STS_NOTSUPP; 920 end_io: 921 bio->bi_status = status; 922 bio_endio(bio); 923 return false; 924 } 925 926 /** 927 * generic_make_request - hand a buffer to its device driver for I/O 928 * @bio: The bio describing the location in memory and on the device. 929 * 930 * generic_make_request() is used to make I/O requests of block 931 * devices. It is passed a &struct bio, which describes the I/O that needs 932 * to be done. 933 * 934 * generic_make_request() does not return any status. The 935 * success/failure status of the request, along with notification of 936 * completion, is delivered asynchronously through the bio->bi_end_io 937 * function described (one day) else where. 938 * 939 * The caller of generic_make_request must make sure that bi_io_vec 940 * are set to describe the memory buffer, and that bi_dev and bi_sector are 941 * set to describe the device address, and the 942 * bi_end_io and optionally bi_private are set to describe how 943 * completion notification should be signaled. 944 * 945 * generic_make_request and the drivers it calls may use bi_next if this 946 * bio happens to be merged with someone else, and may resubmit the bio to 947 * a lower device by calling into generic_make_request recursively, which 948 * means the bio should NOT be touched after the call to ->make_request_fn. 949 */ 950 blk_qc_t generic_make_request(struct bio *bio) 951 { 952 /* 953 * bio_list_on_stack[0] contains bios submitted by the current 954 * make_request_fn. 955 * bio_list_on_stack[1] contains bios that were submitted before 956 * the current make_request_fn, but that haven't been processed 957 * yet. 958 */ 959 struct bio_list bio_list_on_stack[2]; 960 blk_qc_t ret = BLK_QC_T_NONE; 961 962 if (!generic_make_request_checks(bio)) 963 goto out; 964 965 /* 966 * We only want one ->make_request_fn to be active at a time, else 967 * stack usage with stacked devices could be a problem. So use 968 * current->bio_list to keep a list of requests submited by a 969 * make_request_fn function. current->bio_list is also used as a 970 * flag to say if generic_make_request is currently active in this 971 * task or not. If it is NULL, then no make_request is active. If 972 * it is non-NULL, then a make_request is active, and new requests 973 * should be added at the tail 974 */ 975 if (current->bio_list) { 976 bio_list_add(¤t->bio_list[0], bio); 977 goto out; 978 } 979 980 /* following loop may be a bit non-obvious, and so deserves some 981 * explanation. 982 * Before entering the loop, bio->bi_next is NULL (as all callers 983 * ensure that) so we have a list with a single bio. 984 * We pretend that we have just taken it off a longer list, so 985 * we assign bio_list to a pointer to the bio_list_on_stack, 986 * thus initialising the bio_list of new bios to be 987 * added. ->make_request() may indeed add some more bios 988 * through a recursive call to generic_make_request. If it 989 * did, we find a non-NULL value in bio_list and re-enter the loop 990 * from the top. In this case we really did just take the bio 991 * of the top of the list (no pretending) and so remove it from 992 * bio_list, and call into ->make_request() again. 993 */ 994 BUG_ON(bio->bi_next); 995 bio_list_init(&bio_list_on_stack[0]); 996 current->bio_list = bio_list_on_stack; 997 do { 998 struct request_queue *q = bio->bi_disk->queue; 999 blk_mq_req_flags_t flags = bio->bi_opf & REQ_NOWAIT ? 1000 BLK_MQ_REQ_NOWAIT : 0; 1001 1002 if (likely(blk_queue_enter(q, flags) == 0)) { 1003 struct bio_list lower, same; 1004 1005 /* Create a fresh bio_list for all subordinate requests */ 1006 bio_list_on_stack[1] = bio_list_on_stack[0]; 1007 bio_list_init(&bio_list_on_stack[0]); 1008 ret = q->make_request_fn(q, bio); 1009 1010 blk_queue_exit(q); 1011 1012 /* sort new bios into those for a lower level 1013 * and those for the same level 1014 */ 1015 bio_list_init(&lower); 1016 bio_list_init(&same); 1017 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) 1018 if (q == bio->bi_disk->queue) 1019 bio_list_add(&same, bio); 1020 else 1021 bio_list_add(&lower, bio); 1022 /* now assemble so we handle the lowest level first */ 1023 bio_list_merge(&bio_list_on_stack[0], &lower); 1024 bio_list_merge(&bio_list_on_stack[0], &same); 1025 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); 1026 } else { 1027 if (unlikely(!blk_queue_dying(q) && 1028 (bio->bi_opf & REQ_NOWAIT))) 1029 bio_wouldblock_error(bio); 1030 else 1031 bio_io_error(bio); 1032 } 1033 bio = bio_list_pop(&bio_list_on_stack[0]); 1034 } while (bio); 1035 current->bio_list = NULL; /* deactivate */ 1036 1037 out: 1038 return ret; 1039 } 1040 EXPORT_SYMBOL(generic_make_request); 1041 1042 /** 1043 * direct_make_request - hand a buffer directly to its device driver for I/O 1044 * @bio: The bio describing the location in memory and on the device. 1045 * 1046 * This function behaves like generic_make_request(), but does not protect 1047 * against recursion. Must only be used if the called driver is known 1048 * to not call generic_make_request (or direct_make_request) again from 1049 * its make_request function. (Calling direct_make_request again from 1050 * a workqueue is perfectly fine as that doesn't recurse). 1051 */ 1052 blk_qc_t direct_make_request(struct bio *bio) 1053 { 1054 struct request_queue *q = bio->bi_disk->queue; 1055 bool nowait = bio->bi_opf & REQ_NOWAIT; 1056 blk_qc_t ret; 1057 1058 if (!generic_make_request_checks(bio)) 1059 return BLK_QC_T_NONE; 1060 1061 if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) { 1062 if (nowait && !blk_queue_dying(q)) 1063 bio->bi_status = BLK_STS_AGAIN; 1064 else 1065 bio->bi_status = BLK_STS_IOERR; 1066 bio_endio(bio); 1067 return BLK_QC_T_NONE; 1068 } 1069 1070 ret = q->make_request_fn(q, bio); 1071 blk_queue_exit(q); 1072 return ret; 1073 } 1074 EXPORT_SYMBOL_GPL(direct_make_request); 1075 1076 /** 1077 * submit_bio - submit a bio to the block device layer for I/O 1078 * @bio: The &struct bio which describes the I/O 1079 * 1080 * submit_bio() is very similar in purpose to generic_make_request(), and 1081 * uses that function to do most of the work. Both are fairly rough 1082 * interfaces; @bio must be presetup and ready for I/O. 1083 * 1084 */ 1085 blk_qc_t submit_bio(struct bio *bio) 1086 { 1087 /* 1088 * If it's a regular read/write or a barrier with data attached, 1089 * go through the normal accounting stuff before submission. 1090 */ 1091 if (bio_has_data(bio)) { 1092 unsigned int count; 1093 1094 if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) 1095 count = queue_logical_block_size(bio->bi_disk->queue) >> 9; 1096 else 1097 count = bio_sectors(bio); 1098 1099 if (op_is_write(bio_op(bio))) { 1100 count_vm_events(PGPGOUT, count); 1101 } else { 1102 task_io_account_read(bio->bi_iter.bi_size); 1103 count_vm_events(PGPGIN, count); 1104 } 1105 1106 if (unlikely(block_dump)) { 1107 char b[BDEVNAME_SIZE]; 1108 printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", 1109 current->comm, task_pid_nr(current), 1110 op_is_write(bio_op(bio)) ? "WRITE" : "READ", 1111 (unsigned long long)bio->bi_iter.bi_sector, 1112 bio_devname(bio, b), count); 1113 } 1114 } 1115 1116 return generic_make_request(bio); 1117 } 1118 EXPORT_SYMBOL(submit_bio); 1119 1120 /** 1121 * blk_cloned_rq_check_limits - Helper function to check a cloned request 1122 * for new the queue limits 1123 * @q: the queue 1124 * @rq: the request being checked 1125 * 1126 * Description: 1127 * @rq may have been made based on weaker limitations of upper-level queues 1128 * in request stacking drivers, and it may violate the limitation of @q. 1129 * Since the block layer and the underlying device driver trust @rq 1130 * after it is inserted to @q, it should be checked against @q before 1131 * the insertion using this generic function. 1132 * 1133 * Request stacking drivers like request-based dm may change the queue 1134 * limits when retrying requests on other queues. Those requests need 1135 * to be checked against the new queue limits again during dispatch. 1136 */ 1137 static int blk_cloned_rq_check_limits(struct request_queue *q, 1138 struct request *rq) 1139 { 1140 if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) { 1141 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n", 1142 __func__, blk_rq_sectors(rq), 1143 blk_queue_get_max_sectors(q, req_op(rq))); 1144 return -EIO; 1145 } 1146 1147 /* 1148 * queue's settings related to segment counting like q->bounce_pfn 1149 * may differ from that of other stacking queues. 1150 * Recalculate it to check the request correctly on this queue's 1151 * limitation. 1152 */ 1153 blk_recalc_rq_segments(rq); 1154 if (rq->nr_phys_segments > queue_max_segments(q)) { 1155 printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n", 1156 __func__, rq->nr_phys_segments, queue_max_segments(q)); 1157 return -EIO; 1158 } 1159 1160 return 0; 1161 } 1162 1163 /** 1164 * blk_insert_cloned_request - Helper for stacking drivers to submit a request 1165 * @q: the queue to submit the request 1166 * @rq: the request being queued 1167 */ 1168 blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq) 1169 { 1170 if (blk_cloned_rq_check_limits(q, rq)) 1171 return BLK_STS_IOERR; 1172 1173 if (rq->rq_disk && 1174 should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) 1175 return BLK_STS_IOERR; 1176 1177 if (blk_queue_io_stat(q)) 1178 blk_account_io_start(rq, true); 1179 1180 /* 1181 * Since we have a scheduler attached on the top device, 1182 * bypass a potential scheduler on the bottom device for 1183 * insert. 1184 */ 1185 return blk_mq_request_issue_directly(rq, true); 1186 } 1187 EXPORT_SYMBOL_GPL(blk_insert_cloned_request); 1188 1189 /** 1190 * blk_rq_err_bytes - determine number of bytes till the next failure boundary 1191 * @rq: request to examine 1192 * 1193 * Description: 1194 * A request could be merge of IOs which require different failure 1195 * handling. This function determines the number of bytes which 1196 * can be failed from the beginning of the request without 1197 * crossing into area which need to be retried further. 1198 * 1199 * Return: 1200 * The number of bytes to fail. 1201 */ 1202 unsigned int blk_rq_err_bytes(const struct request *rq) 1203 { 1204 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; 1205 unsigned int bytes = 0; 1206 struct bio *bio; 1207 1208 if (!(rq->rq_flags & RQF_MIXED_MERGE)) 1209 return blk_rq_bytes(rq); 1210 1211 /* 1212 * Currently the only 'mixing' which can happen is between 1213 * different fastfail types. We can safely fail portions 1214 * which have all the failfast bits that the first one has - 1215 * the ones which are at least as eager to fail as the first 1216 * one. 1217 */ 1218 for (bio = rq->bio; bio; bio = bio->bi_next) { 1219 if ((bio->bi_opf & ff) != ff) 1220 break; 1221 bytes += bio->bi_iter.bi_size; 1222 } 1223 1224 /* this could lead to infinite loop */ 1225 BUG_ON(blk_rq_bytes(rq) && !bytes); 1226 return bytes; 1227 } 1228 EXPORT_SYMBOL_GPL(blk_rq_err_bytes); 1229 1230 void blk_account_io_completion(struct request *req, unsigned int bytes) 1231 { 1232 if (blk_do_io_stat(req)) { 1233 const int sgrp = op_stat_group(req_op(req)); 1234 struct hd_struct *part; 1235 1236 part_stat_lock(); 1237 part = req->part; 1238 part_stat_add(part, sectors[sgrp], bytes >> 9); 1239 part_stat_unlock(); 1240 } 1241 } 1242 1243 void blk_account_io_done(struct request *req, u64 now) 1244 { 1245 /* 1246 * Account IO completion. flush_rq isn't accounted as a 1247 * normal IO on queueing nor completion. Accounting the 1248 * containing request is enough. 1249 */ 1250 if (blk_do_io_stat(req) && !(req->rq_flags & RQF_FLUSH_SEQ)) { 1251 const int sgrp = op_stat_group(req_op(req)); 1252 struct hd_struct *part; 1253 1254 part_stat_lock(); 1255 part = req->part; 1256 1257 update_io_ticks(part, jiffies); 1258 part_stat_inc(part, ios[sgrp]); 1259 part_stat_add(part, nsecs[sgrp], now - req->start_time_ns); 1260 part_stat_add(part, time_in_queue, nsecs_to_jiffies64(now - req->start_time_ns)); 1261 part_dec_in_flight(req->q, part, rq_data_dir(req)); 1262 1263 hd_struct_put(part); 1264 part_stat_unlock(); 1265 } 1266 } 1267 1268 void blk_account_io_start(struct request *rq, bool new_io) 1269 { 1270 struct hd_struct *part; 1271 int rw = rq_data_dir(rq); 1272 1273 if (!blk_do_io_stat(rq)) 1274 return; 1275 1276 part_stat_lock(); 1277 1278 if (!new_io) { 1279 part = rq->part; 1280 part_stat_inc(part, merges[rw]); 1281 } else { 1282 part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); 1283 if (!hd_struct_try_get(part)) { 1284 /* 1285 * The partition is already being removed, 1286 * the request will be accounted on the disk only 1287 * 1288 * We take a reference on disk->part0 although that 1289 * partition will never be deleted, so we can treat 1290 * it as any other partition. 1291 */ 1292 part = &rq->rq_disk->part0; 1293 hd_struct_get(part); 1294 } 1295 part_inc_in_flight(rq->q, part, rw); 1296 rq->part = part; 1297 } 1298 1299 update_io_ticks(part, jiffies); 1300 1301 part_stat_unlock(); 1302 } 1303 1304 /* 1305 * Steal bios from a request and add them to a bio list. 1306 * The request must not have been partially completed before. 1307 */ 1308 void blk_steal_bios(struct bio_list *list, struct request *rq) 1309 { 1310 if (rq->bio) { 1311 if (list->tail) 1312 list->tail->bi_next = rq->bio; 1313 else 1314 list->head = rq->bio; 1315 list->tail = rq->biotail; 1316 1317 rq->bio = NULL; 1318 rq->biotail = NULL; 1319 } 1320 1321 rq->__data_len = 0; 1322 } 1323 EXPORT_SYMBOL_GPL(blk_steal_bios); 1324 1325 /** 1326 * blk_update_request - Special helper function for request stacking drivers 1327 * @req: the request being processed 1328 * @error: block status code 1329 * @nr_bytes: number of bytes to complete @req 1330 * 1331 * Description: 1332 * Ends I/O on a number of bytes attached to @req, but doesn't complete 1333 * the request structure even if @req doesn't have leftover. 1334 * If @req has leftover, sets it up for the next range of segments. 1335 * 1336 * This special helper function is only for request stacking drivers 1337 * (e.g. request-based dm) so that they can handle partial completion. 1338 * Actual device drivers should use blk_end_request instead. 1339 * 1340 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees 1341 * %false return from this function. 1342 * 1343 * Note: 1344 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in both 1345 * blk_rq_bytes() and in blk_update_request(). 1346 * 1347 * Return: 1348 * %false - this request doesn't have any more data 1349 * %true - this request has more data 1350 **/ 1351 bool blk_update_request(struct request *req, blk_status_t error, 1352 unsigned int nr_bytes) 1353 { 1354 int total_bytes; 1355 1356 trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes); 1357 1358 if (!req->bio) 1359 return false; 1360 1361 if (unlikely(error && !blk_rq_is_passthrough(req) && 1362 !(req->rq_flags & RQF_QUIET))) 1363 print_req_error(req, error); 1364 1365 blk_account_io_completion(req, nr_bytes); 1366 1367 total_bytes = 0; 1368 while (req->bio) { 1369 struct bio *bio = req->bio; 1370 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); 1371 1372 if (bio_bytes == bio->bi_iter.bi_size) 1373 req->bio = bio->bi_next; 1374 1375 /* Completion has already been traced */ 1376 bio_clear_flag(bio, BIO_TRACE_COMPLETION); 1377 req_bio_endio(req, bio, bio_bytes, error); 1378 1379 total_bytes += bio_bytes; 1380 nr_bytes -= bio_bytes; 1381 1382 if (!nr_bytes) 1383 break; 1384 } 1385 1386 /* 1387 * completely done 1388 */ 1389 if (!req->bio) { 1390 /* 1391 * Reset counters so that the request stacking driver 1392 * can find how many bytes remain in the request 1393 * later. 1394 */ 1395 req->__data_len = 0; 1396 return false; 1397 } 1398 1399 req->__data_len -= total_bytes; 1400 1401 /* update sector only for requests with clear definition of sector */ 1402 if (!blk_rq_is_passthrough(req)) 1403 req->__sector += total_bytes >> 9; 1404 1405 /* mixed attributes always follow the first bio */ 1406 if (req->rq_flags & RQF_MIXED_MERGE) { 1407 req->cmd_flags &= ~REQ_FAILFAST_MASK; 1408 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; 1409 } 1410 1411 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { 1412 /* 1413 * If total number of sectors is less than the first segment 1414 * size, something has gone terribly wrong. 1415 */ 1416 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { 1417 blk_dump_rq_flags(req, "request botched"); 1418 req->__data_len = blk_rq_cur_bytes(req); 1419 } 1420 1421 /* recalculate the number of segments */ 1422 blk_recalc_rq_segments(req); 1423 } 1424 1425 return true; 1426 } 1427 EXPORT_SYMBOL_GPL(blk_update_request); 1428 1429 void blk_rq_bio_prep(struct request_queue *q, struct request *rq, 1430 struct bio *bio) 1431 { 1432 if (bio_has_data(bio)) 1433 rq->nr_phys_segments = bio_phys_segments(q, bio); 1434 else if (bio_op(bio) == REQ_OP_DISCARD) 1435 rq->nr_phys_segments = 1; 1436 1437 rq->__data_len = bio->bi_iter.bi_size; 1438 rq->bio = rq->biotail = bio; 1439 1440 if (bio->bi_disk) 1441 rq->rq_disk = bio->bi_disk; 1442 } 1443 1444 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1445 /** 1446 * rq_flush_dcache_pages - Helper function to flush all pages in a request 1447 * @rq: the request to be flushed 1448 * 1449 * Description: 1450 * Flush all pages in @rq. 1451 */ 1452 void rq_flush_dcache_pages(struct request *rq) 1453 { 1454 struct req_iterator iter; 1455 struct bio_vec bvec; 1456 1457 rq_for_each_segment(bvec, rq, iter) 1458 flush_dcache_page(bvec.bv_page); 1459 } 1460 EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); 1461 #endif 1462 1463 /** 1464 * blk_lld_busy - Check if underlying low-level drivers of a device are busy 1465 * @q : the queue of the device being checked 1466 * 1467 * Description: 1468 * Check if underlying low-level drivers of a device are busy. 1469 * If the drivers want to export their busy state, they must set own 1470 * exporting function using blk_queue_lld_busy() first. 1471 * 1472 * Basically, this function is used only by request stacking drivers 1473 * to stop dispatching requests to underlying devices when underlying 1474 * devices are busy. This behavior helps more I/O merging on the queue 1475 * of the request stacking driver and prevents I/O throughput regression 1476 * on burst I/O load. 1477 * 1478 * Return: 1479 * 0 - Not busy (The request stacking driver should dispatch request) 1480 * 1 - Busy (The request stacking driver should stop dispatching request) 1481 */ 1482 int blk_lld_busy(struct request_queue *q) 1483 { 1484 if (queue_is_mq(q) && q->mq_ops->busy) 1485 return q->mq_ops->busy(q); 1486 1487 return 0; 1488 } 1489 EXPORT_SYMBOL_GPL(blk_lld_busy); 1490 1491 /** 1492 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request 1493 * @rq: the clone request to be cleaned up 1494 * 1495 * Description: 1496 * Free all bios in @rq for a cloned request. 1497 */ 1498 void blk_rq_unprep_clone(struct request *rq) 1499 { 1500 struct bio *bio; 1501 1502 while ((bio = rq->bio) != NULL) { 1503 rq->bio = bio->bi_next; 1504 1505 bio_put(bio); 1506 } 1507 } 1508 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); 1509 1510 /* 1511 * Copy attributes of the original request to the clone request. 1512 * The actual data parts (e.g. ->cmd, ->sense) are not copied. 1513 */ 1514 static void __blk_rq_prep_clone(struct request *dst, struct request *src) 1515 { 1516 dst->__sector = blk_rq_pos(src); 1517 dst->__data_len = blk_rq_bytes(src); 1518 if (src->rq_flags & RQF_SPECIAL_PAYLOAD) { 1519 dst->rq_flags |= RQF_SPECIAL_PAYLOAD; 1520 dst->special_vec = src->special_vec; 1521 } 1522 dst->nr_phys_segments = src->nr_phys_segments; 1523 dst->ioprio = src->ioprio; 1524 dst->extra_len = src->extra_len; 1525 } 1526 1527 /** 1528 * blk_rq_prep_clone - Helper function to setup clone request 1529 * @rq: the request to be setup 1530 * @rq_src: original request to be cloned 1531 * @bs: bio_set that bios for clone are allocated from 1532 * @gfp_mask: memory allocation mask for bio 1533 * @bio_ctr: setup function to be called for each clone bio. 1534 * Returns %0 for success, non %0 for failure. 1535 * @data: private data to be passed to @bio_ctr 1536 * 1537 * Description: 1538 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. 1539 * The actual data parts of @rq_src (e.g. ->cmd, ->sense) 1540 * are not copied, and copying such parts is the caller's responsibility. 1541 * Also, pages which the original bios are pointing to are not copied 1542 * and the cloned bios just point same pages. 1543 * So cloned bios must be completed before original bios, which means 1544 * the caller must complete @rq before @rq_src. 1545 */ 1546 int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 1547 struct bio_set *bs, gfp_t gfp_mask, 1548 int (*bio_ctr)(struct bio *, struct bio *, void *), 1549 void *data) 1550 { 1551 struct bio *bio, *bio_src; 1552 1553 if (!bs) 1554 bs = &fs_bio_set; 1555 1556 __rq_for_each_bio(bio_src, rq_src) { 1557 bio = bio_clone_fast(bio_src, gfp_mask, bs); 1558 if (!bio) 1559 goto free_and_out; 1560 1561 if (bio_ctr && bio_ctr(bio, bio_src, data)) 1562 goto free_and_out; 1563 1564 if (rq->bio) { 1565 rq->biotail->bi_next = bio; 1566 rq->biotail = bio; 1567 } else 1568 rq->bio = rq->biotail = bio; 1569 } 1570 1571 __blk_rq_prep_clone(rq, rq_src); 1572 1573 return 0; 1574 1575 free_and_out: 1576 if (bio) 1577 bio_put(bio); 1578 blk_rq_unprep_clone(rq); 1579 1580 return -ENOMEM; 1581 } 1582 EXPORT_SYMBOL_GPL(blk_rq_prep_clone); 1583 1584 int kblockd_schedule_work(struct work_struct *work) 1585 { 1586 return queue_work(kblockd_workqueue, work); 1587 } 1588 EXPORT_SYMBOL(kblockd_schedule_work); 1589 1590 int kblockd_schedule_work_on(int cpu, struct work_struct *work) 1591 { 1592 return queue_work_on(cpu, kblockd_workqueue, work); 1593 } 1594 EXPORT_SYMBOL(kblockd_schedule_work_on); 1595 1596 int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, 1597 unsigned long delay) 1598 { 1599 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); 1600 } 1601 EXPORT_SYMBOL(kblockd_mod_delayed_work_on); 1602 1603 /** 1604 * blk_start_plug - initialize blk_plug and track it inside the task_struct 1605 * @plug: The &struct blk_plug that needs to be initialized 1606 * 1607 * Description: 1608 * blk_start_plug() indicates to the block layer an intent by the caller 1609 * to submit multiple I/O requests in a batch. The block layer may use 1610 * this hint to defer submitting I/Os from the caller until blk_finish_plug() 1611 * is called. However, the block layer may choose to submit requests 1612 * before a call to blk_finish_plug() if the number of queued I/Os 1613 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than 1614 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if 1615 * the task schedules (see below). 1616 * 1617 * Tracking blk_plug inside the task_struct will help with auto-flushing the 1618 * pending I/O should the task end up blocking between blk_start_plug() and 1619 * blk_finish_plug(). This is important from a performance perspective, but 1620 * also ensures that we don't deadlock. For instance, if the task is blocking 1621 * for a memory allocation, memory reclaim could end up wanting to free a 1622 * page belonging to that request that is currently residing in our private 1623 * plug. By flushing the pending I/O when the process goes to sleep, we avoid 1624 * this kind of deadlock. 1625 */ 1626 void blk_start_plug(struct blk_plug *plug) 1627 { 1628 struct task_struct *tsk = current; 1629 1630 /* 1631 * If this is a nested plug, don't actually assign it. 1632 */ 1633 if (tsk->plug) 1634 return; 1635 1636 INIT_LIST_HEAD(&plug->mq_list); 1637 INIT_LIST_HEAD(&plug->cb_list); 1638 plug->rq_count = 0; 1639 plug->multiple_queues = false; 1640 1641 /* 1642 * Store ordering should not be needed here, since a potential 1643 * preempt will imply a full memory barrier 1644 */ 1645 tsk->plug = plug; 1646 } 1647 EXPORT_SYMBOL(blk_start_plug); 1648 1649 static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) 1650 { 1651 LIST_HEAD(callbacks); 1652 1653 while (!list_empty(&plug->cb_list)) { 1654 list_splice_init(&plug->cb_list, &callbacks); 1655 1656 while (!list_empty(&callbacks)) { 1657 struct blk_plug_cb *cb = list_first_entry(&callbacks, 1658 struct blk_plug_cb, 1659 list); 1660 list_del(&cb->list); 1661 cb->callback(cb, from_schedule); 1662 } 1663 } 1664 } 1665 1666 struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, 1667 int size) 1668 { 1669 struct blk_plug *plug = current->plug; 1670 struct blk_plug_cb *cb; 1671 1672 if (!plug) 1673 return NULL; 1674 1675 list_for_each_entry(cb, &plug->cb_list, list) 1676 if (cb->callback == unplug && cb->data == data) 1677 return cb; 1678 1679 /* Not currently on the callback list */ 1680 BUG_ON(size < sizeof(*cb)); 1681 cb = kzalloc(size, GFP_ATOMIC); 1682 if (cb) { 1683 cb->data = data; 1684 cb->callback = unplug; 1685 list_add(&cb->list, &plug->cb_list); 1686 } 1687 return cb; 1688 } 1689 EXPORT_SYMBOL(blk_check_plugged); 1690 1691 void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) 1692 { 1693 flush_plug_callbacks(plug, from_schedule); 1694 1695 if (!list_empty(&plug->mq_list)) 1696 blk_mq_flush_plug_list(plug, from_schedule); 1697 } 1698 1699 /** 1700 * blk_finish_plug - mark the end of a batch of submitted I/O 1701 * @plug: The &struct blk_plug passed to blk_start_plug() 1702 * 1703 * Description: 1704 * Indicate that a batch of I/O submissions is complete. This function 1705 * must be paired with an initial call to blk_start_plug(). The intent 1706 * is to allow the block layer to optimize I/O submission. See the 1707 * documentation for blk_start_plug() for more information. 1708 */ 1709 void blk_finish_plug(struct blk_plug *plug) 1710 { 1711 if (plug != current->plug) 1712 return; 1713 blk_flush_plug_list(plug, false); 1714 1715 current->plug = NULL; 1716 } 1717 EXPORT_SYMBOL(blk_finish_plug); 1718 1719 int __init blk_dev_init(void) 1720 { 1721 BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS)); 1722 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1723 FIELD_SIZEOF(struct request, cmd_flags)); 1724 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1725 FIELD_SIZEOF(struct bio, bi_opf)); 1726 1727 /* used for unplugging and affects IO latency/throughput - HIGHPRI */ 1728 kblockd_workqueue = alloc_workqueue("kblockd", 1729 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); 1730 if (!kblockd_workqueue) 1731 panic("Failed to create kblockd\n"); 1732 1733 blk_requestq_cachep = kmem_cache_create("request_queue", 1734 sizeof(struct request_queue), 0, SLAB_PANIC, NULL); 1735 1736 #ifdef CONFIG_DEBUG_FS 1737 blk_debugfs_root = debugfs_create_dir("block", NULL); 1738 #endif 1739 1740 return 0; 1741 } 1742