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/pagemap.h> 24 #include <linux/kernel_stat.h> 25 #include <linux/string.h> 26 #include <linux/init.h> 27 #include <linux/completion.h> 28 #include <linux/slab.h> 29 #include <linux/swap.h> 30 #include <linux/writeback.h> 31 #include <linux/task_io_accounting_ops.h> 32 #include <linux/fault-inject.h> 33 #include <linux/list_sort.h> 34 #include <linux/delay.h> 35 #include <linux/ratelimit.h> 36 #include <linux/pm_runtime.h> 37 #include <linux/blk-cgroup.h> 38 #include <linux/t10-pi.h> 39 #include <linux/debugfs.h> 40 #include <linux/bpf.h> 41 #include <linux/psi.h> 42 #include <linux/sched/sysctl.h> 43 #include <linux/blk-crypto.h> 44 45 #define CREATE_TRACE_POINTS 46 #include <trace/events/block.h> 47 48 #include "blk.h" 49 #include "blk-mq.h" 50 #include "blk-mq-sched.h" 51 #include "blk-pm.h" 52 #include "blk-rq-qos.h" 53 54 struct dentry *blk_debugfs_root; 55 56 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); 57 EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); 58 EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); 59 EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); 60 EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); 61 62 DEFINE_IDA(blk_queue_ida); 63 64 /* 65 * For queue allocation 66 */ 67 struct kmem_cache *blk_requestq_cachep; 68 69 /* 70 * Controlling structure to kblockd 71 */ 72 static struct workqueue_struct *kblockd_workqueue; 73 74 /** 75 * blk_queue_flag_set - atomically set a queue flag 76 * @flag: flag to be set 77 * @q: request queue 78 */ 79 void blk_queue_flag_set(unsigned int flag, struct request_queue *q) 80 { 81 set_bit(flag, &q->queue_flags); 82 } 83 EXPORT_SYMBOL(blk_queue_flag_set); 84 85 /** 86 * blk_queue_flag_clear - atomically clear a queue flag 87 * @flag: flag to be cleared 88 * @q: request queue 89 */ 90 void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) 91 { 92 clear_bit(flag, &q->queue_flags); 93 } 94 EXPORT_SYMBOL(blk_queue_flag_clear); 95 96 /** 97 * blk_queue_flag_test_and_set - atomically test and set a queue flag 98 * @flag: flag to be set 99 * @q: request queue 100 * 101 * Returns the previous value of @flag - 0 if the flag was not set and 1 if 102 * the flag was already set. 103 */ 104 bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) 105 { 106 return test_and_set_bit(flag, &q->queue_flags); 107 } 108 EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); 109 110 void blk_rq_init(struct request_queue *q, struct request *rq) 111 { 112 memset(rq, 0, sizeof(*rq)); 113 114 INIT_LIST_HEAD(&rq->queuelist); 115 rq->q = q; 116 rq->__sector = (sector_t) -1; 117 INIT_HLIST_NODE(&rq->hash); 118 RB_CLEAR_NODE(&rq->rb_node); 119 rq->tag = -1; 120 rq->internal_tag = -1; 121 rq->start_time_ns = ktime_get_ns(); 122 rq->part = NULL; 123 refcount_set(&rq->ref, 1); 124 blk_crypto_rq_set_defaults(rq); 125 } 126 EXPORT_SYMBOL(blk_rq_init); 127 128 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name 129 static const char *const blk_op_name[] = { 130 REQ_OP_NAME(READ), 131 REQ_OP_NAME(WRITE), 132 REQ_OP_NAME(FLUSH), 133 REQ_OP_NAME(DISCARD), 134 REQ_OP_NAME(SECURE_ERASE), 135 REQ_OP_NAME(ZONE_RESET), 136 REQ_OP_NAME(ZONE_RESET_ALL), 137 REQ_OP_NAME(ZONE_OPEN), 138 REQ_OP_NAME(ZONE_CLOSE), 139 REQ_OP_NAME(ZONE_FINISH), 140 REQ_OP_NAME(ZONE_APPEND), 141 REQ_OP_NAME(WRITE_SAME), 142 REQ_OP_NAME(WRITE_ZEROES), 143 REQ_OP_NAME(SCSI_IN), 144 REQ_OP_NAME(SCSI_OUT), 145 REQ_OP_NAME(DRV_IN), 146 REQ_OP_NAME(DRV_OUT), 147 }; 148 #undef REQ_OP_NAME 149 150 /** 151 * blk_op_str - Return string XXX in the REQ_OP_XXX. 152 * @op: REQ_OP_XXX. 153 * 154 * Description: Centralize block layer function to convert REQ_OP_XXX into 155 * string format. Useful in the debugging and tracing bio or request. For 156 * invalid REQ_OP_XXX it returns string "UNKNOWN". 157 */ 158 inline const char *blk_op_str(unsigned int op) 159 { 160 const char *op_str = "UNKNOWN"; 161 162 if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op]) 163 op_str = blk_op_name[op]; 164 165 return op_str; 166 } 167 EXPORT_SYMBOL_GPL(blk_op_str); 168 169 static const struct { 170 int errno; 171 const char *name; 172 } blk_errors[] = { 173 [BLK_STS_OK] = { 0, "" }, 174 [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, 175 [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, 176 [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, 177 [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, 178 [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, 179 [BLK_STS_NEXUS] = { -EBADE, "critical nexus" }, 180 [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, 181 [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, 182 [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, 183 [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" }, 184 [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, 185 186 /* device mapper special case, should not leak out: */ 187 [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, 188 189 /* everything else not covered above: */ 190 [BLK_STS_IOERR] = { -EIO, "I/O" }, 191 }; 192 193 blk_status_t errno_to_blk_status(int errno) 194 { 195 int i; 196 197 for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { 198 if (blk_errors[i].errno == errno) 199 return (__force blk_status_t)i; 200 } 201 202 return BLK_STS_IOERR; 203 } 204 EXPORT_SYMBOL_GPL(errno_to_blk_status); 205 206 int blk_status_to_errno(blk_status_t status) 207 { 208 int idx = (__force int)status; 209 210 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) 211 return -EIO; 212 return blk_errors[idx].errno; 213 } 214 EXPORT_SYMBOL_GPL(blk_status_to_errno); 215 216 static void print_req_error(struct request *req, blk_status_t status, 217 const char *caller) 218 { 219 int idx = (__force int)status; 220 221 if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) 222 return; 223 224 printk_ratelimited(KERN_ERR 225 "%s: %s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x " 226 "phys_seg %u prio class %u\n", 227 caller, blk_errors[idx].name, 228 req->rq_disk ? req->rq_disk->disk_name : "?", 229 blk_rq_pos(req), req_op(req), blk_op_str(req_op(req)), 230 req->cmd_flags & ~REQ_OP_MASK, 231 req->nr_phys_segments, 232 IOPRIO_PRIO_CLASS(req->ioprio)); 233 } 234 235 static void req_bio_endio(struct request *rq, struct bio *bio, 236 unsigned int nbytes, blk_status_t error) 237 { 238 if (error) 239 bio->bi_status = error; 240 241 if (unlikely(rq->rq_flags & RQF_QUIET)) 242 bio_set_flag(bio, BIO_QUIET); 243 244 bio_advance(bio, nbytes); 245 246 if (req_op(rq) == REQ_OP_ZONE_APPEND && error == BLK_STS_OK) { 247 /* 248 * Partial zone append completions cannot be supported as the 249 * BIO fragments may end up not being written sequentially. 250 */ 251 if (bio->bi_iter.bi_size) 252 bio->bi_status = BLK_STS_IOERR; 253 else 254 bio->bi_iter.bi_sector = rq->__sector; 255 } 256 257 /* don't actually finish bio if it's part of flush sequence */ 258 if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) 259 bio_endio(bio); 260 } 261 262 void blk_dump_rq_flags(struct request *rq, char *msg) 263 { 264 printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg, 265 rq->rq_disk ? rq->rq_disk->disk_name : "?", 266 (unsigned long long) rq->cmd_flags); 267 268 printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", 269 (unsigned long long)blk_rq_pos(rq), 270 blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); 271 printk(KERN_INFO " bio %p, biotail %p, len %u\n", 272 rq->bio, rq->biotail, blk_rq_bytes(rq)); 273 } 274 EXPORT_SYMBOL(blk_dump_rq_flags); 275 276 /** 277 * blk_sync_queue - cancel any pending callbacks on a queue 278 * @q: the queue 279 * 280 * Description: 281 * The block layer may perform asynchronous callback activity 282 * on a queue, such as calling the unplug function after a timeout. 283 * A block device may call blk_sync_queue to ensure that any 284 * such activity is cancelled, thus allowing it to release resources 285 * that the callbacks might use. The caller must already have made sure 286 * that its ->submit_bio will not re-add plugging prior to calling 287 * this function. 288 * 289 * This function does not cancel any asynchronous activity arising 290 * out of elevator or throttling code. That would require elevator_exit() 291 * and blkcg_exit_queue() to be called with queue lock initialized. 292 * 293 */ 294 void blk_sync_queue(struct request_queue *q) 295 { 296 del_timer_sync(&q->timeout); 297 cancel_work_sync(&q->timeout_work); 298 } 299 EXPORT_SYMBOL(blk_sync_queue); 300 301 /** 302 * blk_set_pm_only - increment pm_only counter 303 * @q: request queue pointer 304 */ 305 void blk_set_pm_only(struct request_queue *q) 306 { 307 atomic_inc(&q->pm_only); 308 } 309 EXPORT_SYMBOL_GPL(blk_set_pm_only); 310 311 void blk_clear_pm_only(struct request_queue *q) 312 { 313 int pm_only; 314 315 pm_only = atomic_dec_return(&q->pm_only); 316 WARN_ON_ONCE(pm_only < 0); 317 if (pm_only == 0) 318 wake_up_all(&q->mq_freeze_wq); 319 } 320 EXPORT_SYMBOL_GPL(blk_clear_pm_only); 321 322 /** 323 * blk_put_queue - decrement the request_queue refcount 324 * @q: the request_queue structure to decrement the refcount for 325 * 326 * Decrements the refcount of the request_queue kobject. When this reaches 0 327 * we'll have blk_release_queue() called. 328 * 329 * Context: Any context, but the last reference must not be dropped from 330 * atomic context. 331 */ 332 void blk_put_queue(struct request_queue *q) 333 { 334 kobject_put(&q->kobj); 335 } 336 EXPORT_SYMBOL(blk_put_queue); 337 338 void blk_set_queue_dying(struct request_queue *q) 339 { 340 blk_queue_flag_set(QUEUE_FLAG_DYING, q); 341 342 /* 343 * When queue DYING flag is set, we need to block new req 344 * entering queue, so we call blk_freeze_queue_start() to 345 * prevent I/O from crossing blk_queue_enter(). 346 */ 347 blk_freeze_queue_start(q); 348 349 if (queue_is_mq(q)) 350 blk_mq_wake_waiters(q); 351 352 /* Make blk_queue_enter() reexamine the DYING flag. */ 353 wake_up_all(&q->mq_freeze_wq); 354 } 355 EXPORT_SYMBOL_GPL(blk_set_queue_dying); 356 357 /** 358 * blk_cleanup_queue - shutdown a request queue 359 * @q: request queue to shutdown 360 * 361 * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and 362 * put it. All future requests will be failed immediately with -ENODEV. 363 * 364 * Context: can sleep 365 */ 366 void blk_cleanup_queue(struct request_queue *q) 367 { 368 /* cannot be called from atomic context */ 369 might_sleep(); 370 371 WARN_ON_ONCE(blk_queue_registered(q)); 372 373 /* mark @q DYING, no new request or merges will be allowed afterwards */ 374 blk_set_queue_dying(q); 375 376 blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); 377 blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); 378 379 /* 380 * Drain all requests queued before DYING marking. Set DEAD flag to 381 * prevent that blk_mq_run_hw_queues() accesses the hardware queues 382 * after draining finished. 383 */ 384 blk_freeze_queue(q); 385 386 rq_qos_exit(q); 387 388 blk_queue_flag_set(QUEUE_FLAG_DEAD, q); 389 390 /* for synchronous bio-based driver finish in-flight integrity i/o */ 391 blk_flush_integrity(); 392 393 /* @q won't process any more request, flush async actions */ 394 del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer); 395 blk_sync_queue(q); 396 397 if (queue_is_mq(q)) 398 blk_mq_exit_queue(q); 399 400 /* 401 * In theory, request pool of sched_tags belongs to request queue. 402 * However, the current implementation requires tag_set for freeing 403 * requests, so free the pool now. 404 * 405 * Queue has become frozen, there can't be any in-queue requests, so 406 * it is safe to free requests now. 407 */ 408 mutex_lock(&q->sysfs_lock); 409 if (q->elevator) 410 blk_mq_sched_free_requests(q); 411 mutex_unlock(&q->sysfs_lock); 412 413 percpu_ref_exit(&q->q_usage_counter); 414 415 /* @q is and will stay empty, shutdown and put */ 416 blk_put_queue(q); 417 } 418 EXPORT_SYMBOL(blk_cleanup_queue); 419 420 /** 421 * blk_queue_enter() - try to increase q->q_usage_counter 422 * @q: request queue pointer 423 * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PREEMPT 424 */ 425 int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) 426 { 427 const bool pm = flags & BLK_MQ_REQ_PREEMPT; 428 429 while (true) { 430 bool success = false; 431 432 rcu_read_lock(); 433 if (percpu_ref_tryget_live(&q->q_usage_counter)) { 434 /* 435 * The code that increments the pm_only counter is 436 * responsible for ensuring that that counter is 437 * globally visible before the queue is unfrozen. 438 */ 439 if (pm || !blk_queue_pm_only(q)) { 440 success = true; 441 } else { 442 percpu_ref_put(&q->q_usage_counter); 443 } 444 } 445 rcu_read_unlock(); 446 447 if (success) 448 return 0; 449 450 if (flags & BLK_MQ_REQ_NOWAIT) 451 return -EBUSY; 452 453 /* 454 * read pair of barrier in blk_freeze_queue_start(), 455 * we need to order reading __PERCPU_REF_DEAD flag of 456 * .q_usage_counter and reading .mq_freeze_depth or 457 * queue dying flag, otherwise the following wait may 458 * never return if the two reads are reordered. 459 */ 460 smp_rmb(); 461 462 wait_event(q->mq_freeze_wq, 463 (!q->mq_freeze_depth && 464 (pm || (blk_pm_request_resume(q), 465 !blk_queue_pm_only(q)))) || 466 blk_queue_dying(q)); 467 if (blk_queue_dying(q)) 468 return -ENODEV; 469 } 470 } 471 472 static inline int bio_queue_enter(struct bio *bio) 473 { 474 struct request_queue *q = bio->bi_disk->queue; 475 bool nowait = bio->bi_opf & REQ_NOWAIT; 476 int ret; 477 478 ret = blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0); 479 if (unlikely(ret)) { 480 if (nowait && !blk_queue_dying(q)) 481 bio_wouldblock_error(bio); 482 else 483 bio_io_error(bio); 484 } 485 486 return ret; 487 } 488 489 void blk_queue_exit(struct request_queue *q) 490 { 491 percpu_ref_put(&q->q_usage_counter); 492 } 493 494 static void blk_queue_usage_counter_release(struct percpu_ref *ref) 495 { 496 struct request_queue *q = 497 container_of(ref, struct request_queue, q_usage_counter); 498 499 wake_up_all(&q->mq_freeze_wq); 500 } 501 502 static void blk_rq_timed_out_timer(struct timer_list *t) 503 { 504 struct request_queue *q = from_timer(q, t, timeout); 505 506 kblockd_schedule_work(&q->timeout_work); 507 } 508 509 static void blk_timeout_work(struct work_struct *work) 510 { 511 } 512 513 struct request_queue *blk_alloc_queue(int node_id) 514 { 515 struct request_queue *q; 516 int ret; 517 518 q = kmem_cache_alloc_node(blk_requestq_cachep, 519 GFP_KERNEL | __GFP_ZERO, node_id); 520 if (!q) 521 return NULL; 522 523 q->last_merge = NULL; 524 525 q->id = ida_simple_get(&blk_queue_ida, 0, 0, GFP_KERNEL); 526 if (q->id < 0) 527 goto fail_q; 528 529 ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); 530 if (ret) 531 goto fail_id; 532 533 q->backing_dev_info = bdi_alloc(node_id); 534 if (!q->backing_dev_info) 535 goto fail_split; 536 537 q->stats = blk_alloc_queue_stats(); 538 if (!q->stats) 539 goto fail_stats; 540 541 q->backing_dev_info->ra_pages = VM_READAHEAD_PAGES; 542 q->backing_dev_info->io_pages = VM_READAHEAD_PAGES; 543 q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK; 544 q->node = node_id; 545 546 timer_setup(&q->backing_dev_info->laptop_mode_wb_timer, 547 laptop_mode_timer_fn, 0); 548 timer_setup(&q->timeout, blk_rq_timed_out_timer, 0); 549 INIT_WORK(&q->timeout_work, blk_timeout_work); 550 INIT_LIST_HEAD(&q->icq_list); 551 #ifdef CONFIG_BLK_CGROUP 552 INIT_LIST_HEAD(&q->blkg_list); 553 #endif 554 555 kobject_init(&q->kobj, &blk_queue_ktype); 556 557 mutex_init(&q->debugfs_mutex); 558 mutex_init(&q->sysfs_lock); 559 mutex_init(&q->sysfs_dir_lock); 560 spin_lock_init(&q->queue_lock); 561 562 init_waitqueue_head(&q->mq_freeze_wq); 563 mutex_init(&q->mq_freeze_lock); 564 565 /* 566 * Init percpu_ref in atomic mode so that it's faster to shutdown. 567 * See blk_register_queue() for details. 568 */ 569 if (percpu_ref_init(&q->q_usage_counter, 570 blk_queue_usage_counter_release, 571 PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) 572 goto fail_bdi; 573 574 if (blkcg_init_queue(q)) 575 goto fail_ref; 576 577 blk_queue_dma_alignment(q, 511); 578 blk_set_default_limits(&q->limits); 579 q->nr_requests = BLKDEV_MAX_RQ; 580 581 return q; 582 583 fail_ref: 584 percpu_ref_exit(&q->q_usage_counter); 585 fail_bdi: 586 blk_free_queue_stats(q->stats); 587 fail_stats: 588 bdi_put(q->backing_dev_info); 589 fail_split: 590 bioset_exit(&q->bio_split); 591 fail_id: 592 ida_simple_remove(&blk_queue_ida, q->id); 593 fail_q: 594 kmem_cache_free(blk_requestq_cachep, q); 595 return NULL; 596 } 597 EXPORT_SYMBOL(blk_alloc_queue); 598 599 /** 600 * blk_get_queue - increment the request_queue refcount 601 * @q: the request_queue structure to increment the refcount for 602 * 603 * Increment the refcount of the request_queue kobject. 604 * 605 * Context: Any context. 606 */ 607 bool blk_get_queue(struct request_queue *q) 608 { 609 if (likely(!blk_queue_dying(q))) { 610 __blk_get_queue(q); 611 return true; 612 } 613 614 return false; 615 } 616 EXPORT_SYMBOL(blk_get_queue); 617 618 /** 619 * blk_get_request - allocate a request 620 * @q: request queue to allocate a request for 621 * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC. 622 * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT. 623 */ 624 struct request *blk_get_request(struct request_queue *q, unsigned int op, 625 blk_mq_req_flags_t flags) 626 { 627 struct request *req; 628 629 WARN_ON_ONCE(op & REQ_NOWAIT); 630 WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PREEMPT)); 631 632 req = blk_mq_alloc_request(q, op, flags); 633 if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn) 634 q->mq_ops->initialize_rq_fn(req); 635 636 return req; 637 } 638 EXPORT_SYMBOL(blk_get_request); 639 640 void blk_put_request(struct request *req) 641 { 642 blk_mq_free_request(req); 643 } 644 EXPORT_SYMBOL(blk_put_request); 645 646 static void blk_account_io_merge_bio(struct request *req) 647 { 648 if (!blk_do_io_stat(req)) 649 return; 650 651 part_stat_lock(); 652 part_stat_inc(req->part, merges[op_stat_group(req_op(req))]); 653 part_stat_unlock(); 654 } 655 656 bool bio_attempt_back_merge(struct request *req, struct bio *bio, 657 unsigned int nr_segs) 658 { 659 const int ff = bio->bi_opf & REQ_FAILFAST_MASK; 660 661 if (!ll_back_merge_fn(req, bio, nr_segs)) 662 return false; 663 664 trace_block_bio_backmerge(req->q, req, bio); 665 rq_qos_merge(req->q, req, bio); 666 667 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) 668 blk_rq_set_mixed_merge(req); 669 670 req->biotail->bi_next = bio; 671 req->biotail = bio; 672 req->__data_len += bio->bi_iter.bi_size; 673 674 bio_crypt_free_ctx(bio); 675 676 blk_account_io_merge_bio(req); 677 return true; 678 } 679 680 bool bio_attempt_front_merge(struct request *req, struct bio *bio, 681 unsigned int nr_segs) 682 { 683 const int ff = bio->bi_opf & REQ_FAILFAST_MASK; 684 685 if (!ll_front_merge_fn(req, bio, nr_segs)) 686 return false; 687 688 trace_block_bio_frontmerge(req->q, req, bio); 689 rq_qos_merge(req->q, req, bio); 690 691 if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) 692 blk_rq_set_mixed_merge(req); 693 694 bio->bi_next = req->bio; 695 req->bio = bio; 696 697 req->__sector = bio->bi_iter.bi_sector; 698 req->__data_len += bio->bi_iter.bi_size; 699 700 bio_crypt_do_front_merge(req, bio); 701 702 blk_account_io_merge_bio(req); 703 return true; 704 } 705 706 bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, 707 struct bio *bio) 708 { 709 unsigned short segments = blk_rq_nr_discard_segments(req); 710 711 if (segments >= queue_max_discard_segments(q)) 712 goto no_merge; 713 if (blk_rq_sectors(req) + bio_sectors(bio) > 714 blk_rq_get_max_sectors(req, blk_rq_pos(req))) 715 goto no_merge; 716 717 rq_qos_merge(q, req, bio); 718 719 req->biotail->bi_next = bio; 720 req->biotail = bio; 721 req->__data_len += bio->bi_iter.bi_size; 722 req->nr_phys_segments = segments + 1; 723 724 blk_account_io_merge_bio(req); 725 return true; 726 no_merge: 727 req_set_nomerge(q, req); 728 return false; 729 } 730 731 /** 732 * blk_attempt_plug_merge - try to merge with %current's plugged list 733 * @q: request_queue new bio is being queued at 734 * @bio: new bio being queued 735 * @nr_segs: number of segments in @bio 736 * @same_queue_rq: pointer to &struct request that gets filled in when 737 * another request associated with @q is found on the plug list 738 * (optional, may be %NULL) 739 * 740 * Determine whether @bio being queued on @q can be merged with a request 741 * on %current's plugged list. Returns %true if merge was successful, 742 * otherwise %false. 743 * 744 * Plugging coalesces IOs from the same issuer for the same purpose without 745 * going through @q->queue_lock. As such it's more of an issuing mechanism 746 * than scheduling, and the request, while may have elvpriv data, is not 747 * added on the elevator at this point. In addition, we don't have 748 * reliable access to the elevator outside queue lock. Only check basic 749 * merging parameters without querying the elevator. 750 * 751 * Caller must ensure !blk_queue_nomerges(q) beforehand. 752 */ 753 bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, 754 unsigned int nr_segs, struct request **same_queue_rq) 755 { 756 struct blk_plug *plug; 757 struct request *rq; 758 struct list_head *plug_list; 759 760 plug = blk_mq_plug(q, bio); 761 if (!plug) 762 return false; 763 764 plug_list = &plug->mq_list; 765 766 list_for_each_entry_reverse(rq, plug_list, queuelist) { 767 bool merged = false; 768 769 if (rq->q == q && same_queue_rq) { 770 /* 771 * Only blk-mq multiple hardware queues case checks the 772 * rq in the same queue, there should be only one such 773 * rq in a queue 774 **/ 775 *same_queue_rq = rq; 776 } 777 778 if (rq->q != q || !blk_rq_merge_ok(rq, bio)) 779 continue; 780 781 switch (blk_try_merge(rq, bio)) { 782 case ELEVATOR_BACK_MERGE: 783 merged = bio_attempt_back_merge(rq, bio, nr_segs); 784 break; 785 case ELEVATOR_FRONT_MERGE: 786 merged = bio_attempt_front_merge(rq, bio, nr_segs); 787 break; 788 case ELEVATOR_DISCARD_MERGE: 789 merged = bio_attempt_discard_merge(q, rq, bio); 790 break; 791 default: 792 break; 793 } 794 795 if (merged) 796 return true; 797 } 798 799 return false; 800 } 801 802 static void handle_bad_sector(struct bio *bio, sector_t maxsector) 803 { 804 char b[BDEVNAME_SIZE]; 805 806 printk(KERN_INFO "attempt to access beyond end of device\n"); 807 printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n", 808 bio_devname(bio, b), bio->bi_opf, 809 (unsigned long long)bio_end_sector(bio), 810 (long long)maxsector); 811 } 812 813 #ifdef CONFIG_FAIL_MAKE_REQUEST 814 815 static DECLARE_FAULT_ATTR(fail_make_request); 816 817 static int __init setup_fail_make_request(char *str) 818 { 819 return setup_fault_attr(&fail_make_request, str); 820 } 821 __setup("fail_make_request=", setup_fail_make_request); 822 823 static bool should_fail_request(struct hd_struct *part, unsigned int bytes) 824 { 825 return part->make_it_fail && should_fail(&fail_make_request, bytes); 826 } 827 828 static int __init fail_make_request_debugfs(void) 829 { 830 struct dentry *dir = fault_create_debugfs_attr("fail_make_request", 831 NULL, &fail_make_request); 832 833 return PTR_ERR_OR_ZERO(dir); 834 } 835 836 late_initcall(fail_make_request_debugfs); 837 838 #else /* CONFIG_FAIL_MAKE_REQUEST */ 839 840 static inline bool should_fail_request(struct hd_struct *part, 841 unsigned int bytes) 842 { 843 return false; 844 } 845 846 #endif /* CONFIG_FAIL_MAKE_REQUEST */ 847 848 static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part) 849 { 850 const int op = bio_op(bio); 851 852 if (part->policy && op_is_write(op)) { 853 char b[BDEVNAME_SIZE]; 854 855 if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) 856 return false; 857 858 WARN_ONCE(1, 859 "Trying to write to read-only block-device %s (partno %d)\n", 860 bio_devname(bio, b), part->partno); 861 /* Older lvm-tools actually trigger this */ 862 return false; 863 } 864 865 return false; 866 } 867 868 static noinline int should_fail_bio(struct bio *bio) 869 { 870 if (should_fail_request(&bio->bi_disk->part0, bio->bi_iter.bi_size)) 871 return -EIO; 872 return 0; 873 } 874 ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); 875 876 /* 877 * Check whether this bio extends beyond the end of the device or partition. 878 * This may well happen - the kernel calls bread() without checking the size of 879 * the device, e.g., when mounting a file system. 880 */ 881 static inline int bio_check_eod(struct bio *bio, sector_t maxsector) 882 { 883 unsigned int nr_sectors = bio_sectors(bio); 884 885 if (nr_sectors && maxsector && 886 (nr_sectors > maxsector || 887 bio->bi_iter.bi_sector > maxsector - nr_sectors)) { 888 handle_bad_sector(bio, maxsector); 889 return -EIO; 890 } 891 return 0; 892 } 893 894 /* 895 * Remap block n of partition p to block n+start(p) of the disk. 896 */ 897 static inline int blk_partition_remap(struct bio *bio) 898 { 899 struct hd_struct *p; 900 int ret = -EIO; 901 902 rcu_read_lock(); 903 p = __disk_get_part(bio->bi_disk, bio->bi_partno); 904 if (unlikely(!p)) 905 goto out; 906 if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) 907 goto out; 908 if (unlikely(bio_check_ro(bio, p))) 909 goto out; 910 911 if (bio_sectors(bio)) { 912 if (bio_check_eod(bio, part_nr_sects_read(p))) 913 goto out; 914 bio->bi_iter.bi_sector += p->start_sect; 915 trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), 916 bio->bi_iter.bi_sector - p->start_sect); 917 } 918 bio->bi_partno = 0; 919 ret = 0; 920 out: 921 rcu_read_unlock(); 922 return ret; 923 } 924 925 /* 926 * Check write append to a zoned block device. 927 */ 928 static inline blk_status_t blk_check_zone_append(struct request_queue *q, 929 struct bio *bio) 930 { 931 sector_t pos = bio->bi_iter.bi_sector; 932 int nr_sectors = bio_sectors(bio); 933 934 /* Only applicable to zoned block devices */ 935 if (!blk_queue_is_zoned(q)) 936 return BLK_STS_NOTSUPP; 937 938 /* The bio sector must point to the start of a sequential zone */ 939 if (pos & (blk_queue_zone_sectors(q) - 1) || 940 !blk_queue_zone_is_seq(q, pos)) 941 return BLK_STS_IOERR; 942 943 /* 944 * Not allowed to cross zone boundaries. Otherwise, the BIO will be 945 * split and could result in non-contiguous sectors being written in 946 * different zones. 947 */ 948 if (nr_sectors > q->limits.chunk_sectors) 949 return BLK_STS_IOERR; 950 951 /* Make sure the BIO is small enough and will not get split */ 952 if (nr_sectors > q->limits.max_zone_append_sectors) 953 return BLK_STS_IOERR; 954 955 bio->bi_opf |= REQ_NOMERGE; 956 957 return BLK_STS_OK; 958 } 959 960 static noinline_for_stack bool submit_bio_checks(struct bio *bio) 961 { 962 struct request_queue *q = bio->bi_disk->queue; 963 blk_status_t status = BLK_STS_IOERR; 964 struct blk_plug *plug; 965 966 might_sleep(); 967 968 plug = blk_mq_plug(q, bio); 969 if (plug && plug->nowait) 970 bio->bi_opf |= REQ_NOWAIT; 971 972 /* 973 * For a REQ_NOWAIT based request, return -EOPNOTSUPP 974 * if queue is not a request based queue. 975 */ 976 if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q)) 977 goto not_supported; 978 979 if (should_fail_bio(bio)) 980 goto end_io; 981 982 if (bio->bi_partno) { 983 if (unlikely(blk_partition_remap(bio))) 984 goto end_io; 985 } else { 986 if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0))) 987 goto end_io; 988 if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk)))) 989 goto end_io; 990 } 991 992 /* 993 * Filter flush bio's early so that bio based drivers without flush 994 * support don't have to worry about them. 995 */ 996 if (op_is_flush(bio->bi_opf) && 997 !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { 998 bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); 999 if (!bio_sectors(bio)) { 1000 status = BLK_STS_OK; 1001 goto end_io; 1002 } 1003 } 1004 1005 if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) 1006 bio->bi_opf &= ~REQ_HIPRI; 1007 1008 switch (bio_op(bio)) { 1009 case REQ_OP_DISCARD: 1010 if (!blk_queue_discard(q)) 1011 goto not_supported; 1012 break; 1013 case REQ_OP_SECURE_ERASE: 1014 if (!blk_queue_secure_erase(q)) 1015 goto not_supported; 1016 break; 1017 case REQ_OP_WRITE_SAME: 1018 if (!q->limits.max_write_same_sectors) 1019 goto not_supported; 1020 break; 1021 case REQ_OP_ZONE_APPEND: 1022 status = blk_check_zone_append(q, bio); 1023 if (status != BLK_STS_OK) 1024 goto end_io; 1025 break; 1026 case REQ_OP_ZONE_RESET: 1027 case REQ_OP_ZONE_OPEN: 1028 case REQ_OP_ZONE_CLOSE: 1029 case REQ_OP_ZONE_FINISH: 1030 if (!blk_queue_is_zoned(q)) 1031 goto not_supported; 1032 break; 1033 case REQ_OP_ZONE_RESET_ALL: 1034 if (!blk_queue_is_zoned(q) || !blk_queue_zone_resetall(q)) 1035 goto not_supported; 1036 break; 1037 case REQ_OP_WRITE_ZEROES: 1038 if (!q->limits.max_write_zeroes_sectors) 1039 goto not_supported; 1040 break; 1041 default: 1042 break; 1043 } 1044 1045 /* 1046 * Various block parts want %current->io_context, so allocate it up 1047 * front rather than dealing with lots of pain to allocate it only 1048 * where needed. This may fail and the block layer knows how to live 1049 * with it. 1050 */ 1051 if (unlikely(!current->io_context)) 1052 create_task_io_context(current, GFP_ATOMIC, q->node); 1053 1054 if (blk_throtl_bio(bio)) { 1055 blkcg_bio_issue_init(bio); 1056 return false; 1057 } 1058 1059 blk_cgroup_bio_start(bio); 1060 blkcg_bio_issue_init(bio); 1061 1062 if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { 1063 trace_block_bio_queue(q, bio); 1064 /* Now that enqueuing has been traced, we need to trace 1065 * completion as well. 1066 */ 1067 bio_set_flag(bio, BIO_TRACE_COMPLETION); 1068 } 1069 return true; 1070 1071 not_supported: 1072 status = BLK_STS_NOTSUPP; 1073 end_io: 1074 bio->bi_status = status; 1075 bio_endio(bio); 1076 return false; 1077 } 1078 1079 static blk_qc_t __submit_bio(struct bio *bio) 1080 { 1081 struct gendisk *disk = bio->bi_disk; 1082 blk_qc_t ret = BLK_QC_T_NONE; 1083 1084 if (blk_crypto_bio_prep(&bio)) { 1085 if (!disk->fops->submit_bio) 1086 return blk_mq_submit_bio(bio); 1087 ret = disk->fops->submit_bio(bio); 1088 } 1089 blk_queue_exit(disk->queue); 1090 return ret; 1091 } 1092 1093 /* 1094 * The loop in this function may be a bit non-obvious, and so deserves some 1095 * explanation: 1096 * 1097 * - Before entering the loop, bio->bi_next is NULL (as all callers ensure 1098 * that), so we have a list with a single bio. 1099 * - We pretend that we have just taken it off a longer list, so we assign 1100 * bio_list to a pointer to the bio_list_on_stack, thus initialising the 1101 * bio_list of new bios to be added. ->submit_bio() may indeed add some more 1102 * bios through a recursive call to submit_bio_noacct. If it did, we find a 1103 * non-NULL value in bio_list and re-enter the loop from the top. 1104 * - In this case we really did just take the bio of the top of the list (no 1105 * pretending) and so remove it from bio_list, and call into ->submit_bio() 1106 * again. 1107 * 1108 * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio. 1109 * bio_list_on_stack[1] contains bios that were submitted before the current 1110 * ->submit_bio_bio, but that haven't been processed yet. 1111 */ 1112 static blk_qc_t __submit_bio_noacct(struct bio *bio) 1113 { 1114 struct bio_list bio_list_on_stack[2]; 1115 blk_qc_t ret = BLK_QC_T_NONE; 1116 1117 BUG_ON(bio->bi_next); 1118 1119 bio_list_init(&bio_list_on_stack[0]); 1120 current->bio_list = bio_list_on_stack; 1121 1122 do { 1123 struct request_queue *q = bio->bi_disk->queue; 1124 struct bio_list lower, same; 1125 1126 if (unlikely(bio_queue_enter(bio) != 0)) 1127 continue; 1128 1129 /* 1130 * Create a fresh bio_list for all subordinate requests. 1131 */ 1132 bio_list_on_stack[1] = bio_list_on_stack[0]; 1133 bio_list_init(&bio_list_on_stack[0]); 1134 1135 ret = __submit_bio(bio); 1136 1137 /* 1138 * Sort new bios into those for a lower level and those for the 1139 * same level. 1140 */ 1141 bio_list_init(&lower); 1142 bio_list_init(&same); 1143 while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) 1144 if (q == bio->bi_disk->queue) 1145 bio_list_add(&same, bio); 1146 else 1147 bio_list_add(&lower, bio); 1148 1149 /* 1150 * Now assemble so we handle the lowest level first. 1151 */ 1152 bio_list_merge(&bio_list_on_stack[0], &lower); 1153 bio_list_merge(&bio_list_on_stack[0], &same); 1154 bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); 1155 } while ((bio = bio_list_pop(&bio_list_on_stack[0]))); 1156 1157 current->bio_list = NULL; 1158 return ret; 1159 } 1160 1161 static blk_qc_t __submit_bio_noacct_mq(struct bio *bio) 1162 { 1163 struct bio_list bio_list[2] = { }; 1164 blk_qc_t ret = BLK_QC_T_NONE; 1165 1166 current->bio_list = bio_list; 1167 1168 do { 1169 struct gendisk *disk = bio->bi_disk; 1170 1171 if (unlikely(bio_queue_enter(bio) != 0)) 1172 continue; 1173 1174 if (!blk_crypto_bio_prep(&bio)) { 1175 blk_queue_exit(disk->queue); 1176 ret = BLK_QC_T_NONE; 1177 continue; 1178 } 1179 1180 ret = blk_mq_submit_bio(bio); 1181 } while ((bio = bio_list_pop(&bio_list[0]))); 1182 1183 current->bio_list = NULL; 1184 return ret; 1185 } 1186 1187 /** 1188 * submit_bio_noacct - re-submit a bio to the block device layer for I/O 1189 * @bio: The bio describing the location in memory and on the device. 1190 * 1191 * This is a version of submit_bio() that shall only be used for I/O that is 1192 * resubmitted to lower level drivers by stacking block drivers. All file 1193 * systems and other upper level users of the block layer should use 1194 * submit_bio() instead. 1195 */ 1196 blk_qc_t submit_bio_noacct(struct bio *bio) 1197 { 1198 if (!submit_bio_checks(bio)) 1199 return BLK_QC_T_NONE; 1200 1201 /* 1202 * We only want one ->submit_bio to be active at a time, else stack 1203 * usage with stacked devices could be a problem. Use current->bio_list 1204 * to collect a list of requests submited by a ->submit_bio method while 1205 * it is active, and then process them after it returned. 1206 */ 1207 if (current->bio_list) { 1208 bio_list_add(¤t->bio_list[0], bio); 1209 return BLK_QC_T_NONE; 1210 } 1211 1212 if (!bio->bi_disk->fops->submit_bio) 1213 return __submit_bio_noacct_mq(bio); 1214 return __submit_bio_noacct(bio); 1215 } 1216 EXPORT_SYMBOL(submit_bio_noacct); 1217 1218 /** 1219 * submit_bio - submit a bio to the block device layer for I/O 1220 * @bio: The &struct bio which describes the I/O 1221 * 1222 * submit_bio() is used to submit I/O requests to block devices. It is passed a 1223 * fully set up &struct bio that describes the I/O that needs to be done. The 1224 * bio will be send to the device described by the bi_disk and bi_partno fields. 1225 * 1226 * The success/failure status of the request, along with notification of 1227 * completion, is delivered asynchronously through the ->bi_end_io() callback 1228 * in @bio. The bio must NOT be touched by thecaller until ->bi_end_io() has 1229 * been called. 1230 */ 1231 blk_qc_t submit_bio(struct bio *bio) 1232 { 1233 if (blkcg_punt_bio_submit(bio)) 1234 return BLK_QC_T_NONE; 1235 1236 /* 1237 * If it's a regular read/write or a barrier with data attached, 1238 * go through the normal accounting stuff before submission. 1239 */ 1240 if (bio_has_data(bio)) { 1241 unsigned int count; 1242 1243 if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) 1244 count = queue_logical_block_size(bio->bi_disk->queue) >> 9; 1245 else 1246 count = bio_sectors(bio); 1247 1248 if (op_is_write(bio_op(bio))) { 1249 count_vm_events(PGPGOUT, count); 1250 } else { 1251 task_io_account_read(bio->bi_iter.bi_size); 1252 count_vm_events(PGPGIN, count); 1253 } 1254 1255 if (unlikely(block_dump)) { 1256 char b[BDEVNAME_SIZE]; 1257 printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", 1258 current->comm, task_pid_nr(current), 1259 op_is_write(bio_op(bio)) ? "WRITE" : "READ", 1260 (unsigned long long)bio->bi_iter.bi_sector, 1261 bio_devname(bio, b), count); 1262 } 1263 } 1264 1265 /* 1266 * If we're reading data that is part of the userspace workingset, count 1267 * submission time as memory stall. When the device is congested, or 1268 * the submitting cgroup IO-throttled, submission can be a significant 1269 * part of overall IO time. 1270 */ 1271 if (unlikely(bio_op(bio) == REQ_OP_READ && 1272 bio_flagged(bio, BIO_WORKINGSET))) { 1273 unsigned long pflags; 1274 blk_qc_t ret; 1275 1276 psi_memstall_enter(&pflags); 1277 ret = submit_bio_noacct(bio); 1278 psi_memstall_leave(&pflags); 1279 1280 return ret; 1281 } 1282 1283 return submit_bio_noacct(bio); 1284 } 1285 EXPORT_SYMBOL(submit_bio); 1286 1287 /** 1288 * blk_cloned_rq_check_limits - Helper function to check a cloned request 1289 * for the new queue limits 1290 * @q: the queue 1291 * @rq: the request being checked 1292 * 1293 * Description: 1294 * @rq may have been made based on weaker limitations of upper-level queues 1295 * in request stacking drivers, and it may violate the limitation of @q. 1296 * Since the block layer and the underlying device driver trust @rq 1297 * after it is inserted to @q, it should be checked against @q before 1298 * the insertion using this generic function. 1299 * 1300 * Request stacking drivers like request-based dm may change the queue 1301 * limits when retrying requests on other queues. Those requests need 1302 * to be checked against the new queue limits again during dispatch. 1303 */ 1304 static int blk_cloned_rq_check_limits(struct request_queue *q, 1305 struct request *rq) 1306 { 1307 if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) { 1308 printk(KERN_ERR "%s: over max size limit. (%u > %u)\n", 1309 __func__, blk_rq_sectors(rq), 1310 blk_queue_get_max_sectors(q, req_op(rq))); 1311 return -EIO; 1312 } 1313 1314 /* 1315 * queue's settings related to segment counting like q->bounce_pfn 1316 * may differ from that of other stacking queues. 1317 * Recalculate it to check the request correctly on this queue's 1318 * limitation. 1319 */ 1320 rq->nr_phys_segments = blk_recalc_rq_segments(rq); 1321 if (rq->nr_phys_segments > queue_max_segments(q)) { 1322 printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n", 1323 __func__, rq->nr_phys_segments, queue_max_segments(q)); 1324 return -EIO; 1325 } 1326 1327 return 0; 1328 } 1329 1330 /** 1331 * blk_insert_cloned_request - Helper for stacking drivers to submit a request 1332 * @q: the queue to submit the request 1333 * @rq: the request being queued 1334 */ 1335 blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq) 1336 { 1337 if (blk_cloned_rq_check_limits(q, rq)) 1338 return BLK_STS_IOERR; 1339 1340 if (rq->rq_disk && 1341 should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) 1342 return BLK_STS_IOERR; 1343 1344 if (blk_crypto_insert_cloned_request(rq)) 1345 return BLK_STS_IOERR; 1346 1347 if (blk_queue_io_stat(q)) 1348 blk_account_io_start(rq); 1349 1350 /* 1351 * Since we have a scheduler attached on the top device, 1352 * bypass a potential scheduler on the bottom device for 1353 * insert. 1354 */ 1355 return blk_mq_request_issue_directly(rq, true); 1356 } 1357 EXPORT_SYMBOL_GPL(blk_insert_cloned_request); 1358 1359 /** 1360 * blk_rq_err_bytes - determine number of bytes till the next failure boundary 1361 * @rq: request to examine 1362 * 1363 * Description: 1364 * A request could be merge of IOs which require different failure 1365 * handling. This function determines the number of bytes which 1366 * can be failed from the beginning of the request without 1367 * crossing into area which need to be retried further. 1368 * 1369 * Return: 1370 * The number of bytes to fail. 1371 */ 1372 unsigned int blk_rq_err_bytes(const struct request *rq) 1373 { 1374 unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; 1375 unsigned int bytes = 0; 1376 struct bio *bio; 1377 1378 if (!(rq->rq_flags & RQF_MIXED_MERGE)) 1379 return blk_rq_bytes(rq); 1380 1381 /* 1382 * Currently the only 'mixing' which can happen is between 1383 * different fastfail types. We can safely fail portions 1384 * which have all the failfast bits that the first one has - 1385 * the ones which are at least as eager to fail as the first 1386 * one. 1387 */ 1388 for (bio = rq->bio; bio; bio = bio->bi_next) { 1389 if ((bio->bi_opf & ff) != ff) 1390 break; 1391 bytes += bio->bi_iter.bi_size; 1392 } 1393 1394 /* this could lead to infinite loop */ 1395 BUG_ON(blk_rq_bytes(rq) && !bytes); 1396 return bytes; 1397 } 1398 EXPORT_SYMBOL_GPL(blk_rq_err_bytes); 1399 1400 static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end) 1401 { 1402 unsigned long stamp; 1403 again: 1404 stamp = READ_ONCE(part->stamp); 1405 if (unlikely(stamp != now)) { 1406 if (likely(cmpxchg(&part->stamp, stamp, now) == stamp)) 1407 __part_stat_add(part, io_ticks, end ? now - stamp : 1); 1408 } 1409 if (part->partno) { 1410 part = &part_to_disk(part)->part0; 1411 goto again; 1412 } 1413 } 1414 1415 static void blk_account_io_completion(struct request *req, unsigned int bytes) 1416 { 1417 if (req->part && blk_do_io_stat(req)) { 1418 const int sgrp = op_stat_group(req_op(req)); 1419 struct hd_struct *part; 1420 1421 part_stat_lock(); 1422 part = req->part; 1423 part_stat_add(part, sectors[sgrp], bytes >> 9); 1424 part_stat_unlock(); 1425 } 1426 } 1427 1428 void blk_account_io_done(struct request *req, u64 now) 1429 { 1430 /* 1431 * Account IO completion. flush_rq isn't accounted as a 1432 * normal IO on queueing nor completion. Accounting the 1433 * containing request is enough. 1434 */ 1435 if (req->part && blk_do_io_stat(req) && 1436 !(req->rq_flags & RQF_FLUSH_SEQ)) { 1437 const int sgrp = op_stat_group(req_op(req)); 1438 struct hd_struct *part; 1439 1440 part_stat_lock(); 1441 part = req->part; 1442 1443 update_io_ticks(part, jiffies, true); 1444 part_stat_inc(part, ios[sgrp]); 1445 part_stat_add(part, nsecs[sgrp], now - req->start_time_ns); 1446 part_stat_unlock(); 1447 1448 hd_struct_put(part); 1449 } 1450 } 1451 1452 void blk_account_io_start(struct request *rq) 1453 { 1454 if (!blk_do_io_stat(rq)) 1455 return; 1456 1457 rq->part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); 1458 1459 part_stat_lock(); 1460 update_io_ticks(rq->part, jiffies, false); 1461 part_stat_unlock(); 1462 } 1463 1464 unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors, 1465 unsigned int op) 1466 { 1467 struct hd_struct *part = &disk->part0; 1468 const int sgrp = op_stat_group(op); 1469 unsigned long now = READ_ONCE(jiffies); 1470 1471 part_stat_lock(); 1472 update_io_ticks(part, now, false); 1473 part_stat_inc(part, ios[sgrp]); 1474 part_stat_add(part, sectors[sgrp], sectors); 1475 part_stat_local_inc(part, in_flight[op_is_write(op)]); 1476 part_stat_unlock(); 1477 1478 return now; 1479 } 1480 EXPORT_SYMBOL(disk_start_io_acct); 1481 1482 void disk_end_io_acct(struct gendisk *disk, unsigned int op, 1483 unsigned long start_time) 1484 { 1485 struct hd_struct *part = &disk->part0; 1486 const int sgrp = op_stat_group(op); 1487 unsigned long now = READ_ONCE(jiffies); 1488 unsigned long duration = now - start_time; 1489 1490 part_stat_lock(); 1491 update_io_ticks(part, now, true); 1492 part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration)); 1493 part_stat_local_dec(part, in_flight[op_is_write(op)]); 1494 part_stat_unlock(); 1495 } 1496 EXPORT_SYMBOL(disk_end_io_acct); 1497 1498 /* 1499 * Steal bios from a request and add them to a bio list. 1500 * The request must not have been partially completed before. 1501 */ 1502 void blk_steal_bios(struct bio_list *list, struct request *rq) 1503 { 1504 if (rq->bio) { 1505 if (list->tail) 1506 list->tail->bi_next = rq->bio; 1507 else 1508 list->head = rq->bio; 1509 list->tail = rq->biotail; 1510 1511 rq->bio = NULL; 1512 rq->biotail = NULL; 1513 } 1514 1515 rq->__data_len = 0; 1516 } 1517 EXPORT_SYMBOL_GPL(blk_steal_bios); 1518 1519 /** 1520 * blk_update_request - Special helper function for request stacking drivers 1521 * @req: the request being processed 1522 * @error: block status code 1523 * @nr_bytes: number of bytes to complete @req 1524 * 1525 * Description: 1526 * Ends I/O on a number of bytes attached to @req, but doesn't complete 1527 * the request structure even if @req doesn't have leftover. 1528 * If @req has leftover, sets it up for the next range of segments. 1529 * 1530 * This special helper function is only for request stacking drivers 1531 * (e.g. request-based dm) so that they can handle partial completion. 1532 * Actual device drivers should use blk_mq_end_request instead. 1533 * 1534 * Passing the result of blk_rq_bytes() as @nr_bytes guarantees 1535 * %false return from this function. 1536 * 1537 * Note: 1538 * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in both 1539 * blk_rq_bytes() and in blk_update_request(). 1540 * 1541 * Return: 1542 * %false - this request doesn't have any more data 1543 * %true - this request has more data 1544 **/ 1545 bool blk_update_request(struct request *req, blk_status_t error, 1546 unsigned int nr_bytes) 1547 { 1548 int total_bytes; 1549 1550 trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes); 1551 1552 if (!req->bio) 1553 return false; 1554 1555 #ifdef CONFIG_BLK_DEV_INTEGRITY 1556 if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ && 1557 error == BLK_STS_OK) 1558 req->q->integrity.profile->complete_fn(req, nr_bytes); 1559 #endif 1560 1561 if (unlikely(error && !blk_rq_is_passthrough(req) && 1562 !(req->rq_flags & RQF_QUIET))) 1563 print_req_error(req, error, __func__); 1564 1565 blk_account_io_completion(req, nr_bytes); 1566 1567 total_bytes = 0; 1568 while (req->bio) { 1569 struct bio *bio = req->bio; 1570 unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); 1571 1572 if (bio_bytes == bio->bi_iter.bi_size) 1573 req->bio = bio->bi_next; 1574 1575 /* Completion has already been traced */ 1576 bio_clear_flag(bio, BIO_TRACE_COMPLETION); 1577 req_bio_endio(req, bio, bio_bytes, error); 1578 1579 total_bytes += bio_bytes; 1580 nr_bytes -= bio_bytes; 1581 1582 if (!nr_bytes) 1583 break; 1584 } 1585 1586 /* 1587 * completely done 1588 */ 1589 if (!req->bio) { 1590 /* 1591 * Reset counters so that the request stacking driver 1592 * can find how many bytes remain in the request 1593 * later. 1594 */ 1595 req->__data_len = 0; 1596 return false; 1597 } 1598 1599 req->__data_len -= total_bytes; 1600 1601 /* update sector only for requests with clear definition of sector */ 1602 if (!blk_rq_is_passthrough(req)) 1603 req->__sector += total_bytes >> 9; 1604 1605 /* mixed attributes always follow the first bio */ 1606 if (req->rq_flags & RQF_MIXED_MERGE) { 1607 req->cmd_flags &= ~REQ_FAILFAST_MASK; 1608 req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; 1609 } 1610 1611 if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { 1612 /* 1613 * If total number of sectors is less than the first segment 1614 * size, something has gone terribly wrong. 1615 */ 1616 if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { 1617 blk_dump_rq_flags(req, "request botched"); 1618 req->__data_len = blk_rq_cur_bytes(req); 1619 } 1620 1621 /* recalculate the number of segments */ 1622 req->nr_phys_segments = blk_recalc_rq_segments(req); 1623 } 1624 1625 return true; 1626 } 1627 EXPORT_SYMBOL_GPL(blk_update_request); 1628 1629 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1630 /** 1631 * rq_flush_dcache_pages - Helper function to flush all pages in a request 1632 * @rq: the request to be flushed 1633 * 1634 * Description: 1635 * Flush all pages in @rq. 1636 */ 1637 void rq_flush_dcache_pages(struct request *rq) 1638 { 1639 struct req_iterator iter; 1640 struct bio_vec bvec; 1641 1642 rq_for_each_segment(bvec, rq, iter) 1643 flush_dcache_page(bvec.bv_page); 1644 } 1645 EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); 1646 #endif 1647 1648 /** 1649 * blk_lld_busy - Check if underlying low-level drivers of a device are busy 1650 * @q : the queue of the device being checked 1651 * 1652 * Description: 1653 * Check if underlying low-level drivers of a device are busy. 1654 * If the drivers want to export their busy state, they must set own 1655 * exporting function using blk_queue_lld_busy() first. 1656 * 1657 * Basically, this function is used only by request stacking drivers 1658 * to stop dispatching requests to underlying devices when underlying 1659 * devices are busy. This behavior helps more I/O merging on the queue 1660 * of the request stacking driver and prevents I/O throughput regression 1661 * on burst I/O load. 1662 * 1663 * Return: 1664 * 0 - Not busy (The request stacking driver should dispatch request) 1665 * 1 - Busy (The request stacking driver should stop dispatching request) 1666 */ 1667 int blk_lld_busy(struct request_queue *q) 1668 { 1669 if (queue_is_mq(q) && q->mq_ops->busy) 1670 return q->mq_ops->busy(q); 1671 1672 return 0; 1673 } 1674 EXPORT_SYMBOL_GPL(blk_lld_busy); 1675 1676 /** 1677 * blk_rq_unprep_clone - Helper function to free all bios in a cloned request 1678 * @rq: the clone request to be cleaned up 1679 * 1680 * Description: 1681 * Free all bios in @rq for a cloned request. 1682 */ 1683 void blk_rq_unprep_clone(struct request *rq) 1684 { 1685 struct bio *bio; 1686 1687 while ((bio = rq->bio) != NULL) { 1688 rq->bio = bio->bi_next; 1689 1690 bio_put(bio); 1691 } 1692 } 1693 EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); 1694 1695 /** 1696 * blk_rq_prep_clone - Helper function to setup clone request 1697 * @rq: the request to be setup 1698 * @rq_src: original request to be cloned 1699 * @bs: bio_set that bios for clone are allocated from 1700 * @gfp_mask: memory allocation mask for bio 1701 * @bio_ctr: setup function to be called for each clone bio. 1702 * Returns %0 for success, non %0 for failure. 1703 * @data: private data to be passed to @bio_ctr 1704 * 1705 * Description: 1706 * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. 1707 * Also, pages which the original bios are pointing to are not copied 1708 * and the cloned bios just point same pages. 1709 * So cloned bios must be completed before original bios, which means 1710 * the caller must complete @rq before @rq_src. 1711 */ 1712 int blk_rq_prep_clone(struct request *rq, struct request *rq_src, 1713 struct bio_set *bs, gfp_t gfp_mask, 1714 int (*bio_ctr)(struct bio *, struct bio *, void *), 1715 void *data) 1716 { 1717 struct bio *bio, *bio_src; 1718 1719 if (!bs) 1720 bs = &fs_bio_set; 1721 1722 __rq_for_each_bio(bio_src, rq_src) { 1723 bio = bio_clone_fast(bio_src, gfp_mask, bs); 1724 if (!bio) 1725 goto free_and_out; 1726 1727 if (bio_ctr && bio_ctr(bio, bio_src, data)) 1728 goto free_and_out; 1729 1730 if (rq->bio) { 1731 rq->biotail->bi_next = bio; 1732 rq->biotail = bio; 1733 } else 1734 rq->bio = rq->biotail = bio; 1735 } 1736 1737 /* Copy attributes of the original request to the clone request. */ 1738 rq->__sector = blk_rq_pos(rq_src); 1739 rq->__data_len = blk_rq_bytes(rq_src); 1740 if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) { 1741 rq->rq_flags |= RQF_SPECIAL_PAYLOAD; 1742 rq->special_vec = rq_src->special_vec; 1743 } 1744 rq->nr_phys_segments = rq_src->nr_phys_segments; 1745 rq->ioprio = rq_src->ioprio; 1746 1747 if (rq->bio) 1748 blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask); 1749 1750 return 0; 1751 1752 free_and_out: 1753 if (bio) 1754 bio_put(bio); 1755 blk_rq_unprep_clone(rq); 1756 1757 return -ENOMEM; 1758 } 1759 EXPORT_SYMBOL_GPL(blk_rq_prep_clone); 1760 1761 int kblockd_schedule_work(struct work_struct *work) 1762 { 1763 return queue_work(kblockd_workqueue, work); 1764 } 1765 EXPORT_SYMBOL(kblockd_schedule_work); 1766 1767 int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, 1768 unsigned long delay) 1769 { 1770 return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); 1771 } 1772 EXPORT_SYMBOL(kblockd_mod_delayed_work_on); 1773 1774 /** 1775 * blk_start_plug - initialize blk_plug and track it inside the task_struct 1776 * @plug: The &struct blk_plug that needs to be initialized 1777 * 1778 * Description: 1779 * blk_start_plug() indicates to the block layer an intent by the caller 1780 * to submit multiple I/O requests in a batch. The block layer may use 1781 * this hint to defer submitting I/Os from the caller until blk_finish_plug() 1782 * is called. However, the block layer may choose to submit requests 1783 * before a call to blk_finish_plug() if the number of queued I/Os 1784 * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than 1785 * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if 1786 * the task schedules (see below). 1787 * 1788 * Tracking blk_plug inside the task_struct will help with auto-flushing the 1789 * pending I/O should the task end up blocking between blk_start_plug() and 1790 * blk_finish_plug(). This is important from a performance perspective, but 1791 * also ensures that we don't deadlock. For instance, if the task is blocking 1792 * for a memory allocation, memory reclaim could end up wanting to free a 1793 * page belonging to that request that is currently residing in our private 1794 * plug. By flushing the pending I/O when the process goes to sleep, we avoid 1795 * this kind of deadlock. 1796 */ 1797 void blk_start_plug(struct blk_plug *plug) 1798 { 1799 struct task_struct *tsk = current; 1800 1801 /* 1802 * If this is a nested plug, don't actually assign it. 1803 */ 1804 if (tsk->plug) 1805 return; 1806 1807 INIT_LIST_HEAD(&plug->mq_list); 1808 INIT_LIST_HEAD(&plug->cb_list); 1809 plug->rq_count = 0; 1810 plug->multiple_queues = false; 1811 plug->nowait = false; 1812 1813 /* 1814 * Store ordering should not be needed here, since a potential 1815 * preempt will imply a full memory barrier 1816 */ 1817 tsk->plug = plug; 1818 } 1819 EXPORT_SYMBOL(blk_start_plug); 1820 1821 static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) 1822 { 1823 LIST_HEAD(callbacks); 1824 1825 while (!list_empty(&plug->cb_list)) { 1826 list_splice_init(&plug->cb_list, &callbacks); 1827 1828 while (!list_empty(&callbacks)) { 1829 struct blk_plug_cb *cb = list_first_entry(&callbacks, 1830 struct blk_plug_cb, 1831 list); 1832 list_del(&cb->list); 1833 cb->callback(cb, from_schedule); 1834 } 1835 } 1836 } 1837 1838 struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, 1839 int size) 1840 { 1841 struct blk_plug *plug = current->plug; 1842 struct blk_plug_cb *cb; 1843 1844 if (!plug) 1845 return NULL; 1846 1847 list_for_each_entry(cb, &plug->cb_list, list) 1848 if (cb->callback == unplug && cb->data == data) 1849 return cb; 1850 1851 /* Not currently on the callback list */ 1852 BUG_ON(size < sizeof(*cb)); 1853 cb = kzalloc(size, GFP_ATOMIC); 1854 if (cb) { 1855 cb->data = data; 1856 cb->callback = unplug; 1857 list_add(&cb->list, &plug->cb_list); 1858 } 1859 return cb; 1860 } 1861 EXPORT_SYMBOL(blk_check_plugged); 1862 1863 void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) 1864 { 1865 flush_plug_callbacks(plug, from_schedule); 1866 1867 if (!list_empty(&plug->mq_list)) 1868 blk_mq_flush_plug_list(plug, from_schedule); 1869 } 1870 1871 /** 1872 * blk_finish_plug - mark the end of a batch of submitted I/O 1873 * @plug: The &struct blk_plug passed to blk_start_plug() 1874 * 1875 * Description: 1876 * Indicate that a batch of I/O submissions is complete. This function 1877 * must be paired with an initial call to blk_start_plug(). The intent 1878 * is to allow the block layer to optimize I/O submission. See the 1879 * documentation for blk_start_plug() for more information. 1880 */ 1881 void blk_finish_plug(struct blk_plug *plug) 1882 { 1883 if (plug != current->plug) 1884 return; 1885 blk_flush_plug_list(plug, false); 1886 1887 current->plug = NULL; 1888 } 1889 EXPORT_SYMBOL(blk_finish_plug); 1890 1891 void blk_io_schedule(void) 1892 { 1893 /* Prevent hang_check timer from firing at us during very long I/O */ 1894 unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; 1895 1896 if (timeout) 1897 io_schedule_timeout(timeout); 1898 else 1899 io_schedule(); 1900 } 1901 EXPORT_SYMBOL_GPL(blk_io_schedule); 1902 1903 int __init blk_dev_init(void) 1904 { 1905 BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS)); 1906 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1907 sizeof_field(struct request, cmd_flags)); 1908 BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * 1909 sizeof_field(struct bio, bi_opf)); 1910 1911 /* used for unplugging and affects IO latency/throughput - HIGHPRI */ 1912 kblockd_workqueue = alloc_workqueue("kblockd", 1913 WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); 1914 if (!kblockd_workqueue) 1915 panic("Failed to create kblockd\n"); 1916 1917 blk_requestq_cachep = kmem_cache_create("request_queue", 1918 sizeof(struct request_queue), 0, SLAB_PANIC, NULL); 1919 1920 blk_debugfs_root = debugfs_create_dir("block", NULL); 1921 1922 return 0; 1923 } 1924