| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright (C) 1994, Karl Keyte: Added support for disk statistics |
| * Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE |
| * Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de> |
| * kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au> |
| * - July2000 |
| * bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001 |
| */ |
| |
| /* |
| * This handles all read/write requests to block devices |
| */ |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/bio.h> |
| #include <linux/blkdev.h> |
| #include <linux/blk-pm.h> |
| #include <linux/blk-integrity.h> |
| #include <linux/highmem.h> |
| #include <linux/mm.h> |
| #include <linux/pagemap.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/string.h> |
| #include <linux/init.h> |
| #include <linux/completion.h> |
| #include <linux/slab.h> |
| #include <linux/swap.h> |
| #include <linux/writeback.h> |
| #include <linux/task_io_accounting_ops.h> |
| #include <linux/fault-inject.h> |
| #include <linux/list_sort.h> |
| #include <linux/delay.h> |
| #include <linux/ratelimit.h> |
| #include <linux/pm_runtime.h> |
| #include <linux/t10-pi.h> |
| #include <linux/debugfs.h> |
| #include <linux/bpf.h> |
| #include <linux/part_stat.h> |
| #include <linux/sched/sysctl.h> |
| #include <linux/blk-crypto.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/block.h> |
| |
| #include "blk.h" |
| #include "blk-mq-sched.h" |
| #include "blk-pm.h" |
| #include "blk-cgroup.h" |
| #include "blk-throttle.h" |
| |
| struct dentry *blk_debugfs_root; |
| |
| EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); |
| EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); |
| EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); |
| EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); |
| EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); |
| EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_insert); |
| |
| DEFINE_IDA(blk_queue_ida); |
| |
| /* |
| * For queue allocation |
| */ |
| struct kmem_cache *blk_requestq_cachep; |
| struct kmem_cache *blk_requestq_srcu_cachep; |
| |
| /* |
| * Controlling structure to kblockd |
| */ |
| static struct workqueue_struct *kblockd_workqueue; |
| |
| /** |
| * blk_queue_flag_set - atomically set a queue flag |
| * @flag: flag to be set |
| * @q: request queue |
| */ |
| void blk_queue_flag_set(unsigned int flag, struct request_queue *q) |
| { |
| set_bit(flag, &q->queue_flags); |
| } |
| EXPORT_SYMBOL(blk_queue_flag_set); |
| |
| /** |
| * blk_queue_flag_clear - atomically clear a queue flag |
| * @flag: flag to be cleared |
| * @q: request queue |
| */ |
| void blk_queue_flag_clear(unsigned int flag, struct request_queue *q) |
| { |
| clear_bit(flag, &q->queue_flags); |
| } |
| EXPORT_SYMBOL(blk_queue_flag_clear); |
| |
| /** |
| * blk_queue_flag_test_and_set - atomically test and set a queue flag |
| * @flag: flag to be set |
| * @q: request queue |
| * |
| * Returns the previous value of @flag - 0 if the flag was not set and 1 if |
| * the flag was already set. |
| */ |
| bool blk_queue_flag_test_and_set(unsigned int flag, struct request_queue *q) |
| { |
| return test_and_set_bit(flag, &q->queue_flags); |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); |
| |
| #define REQ_OP_NAME(name) [REQ_OP_##name] = #name |
| static const char *const blk_op_name[] = { |
| REQ_OP_NAME(READ), |
| REQ_OP_NAME(WRITE), |
| REQ_OP_NAME(FLUSH), |
| REQ_OP_NAME(DISCARD), |
| REQ_OP_NAME(SECURE_ERASE), |
| REQ_OP_NAME(ZONE_RESET), |
| REQ_OP_NAME(ZONE_RESET_ALL), |
| REQ_OP_NAME(ZONE_OPEN), |
| REQ_OP_NAME(ZONE_CLOSE), |
| REQ_OP_NAME(ZONE_FINISH), |
| REQ_OP_NAME(ZONE_APPEND), |
| REQ_OP_NAME(WRITE_ZEROES), |
| REQ_OP_NAME(DRV_IN), |
| REQ_OP_NAME(DRV_OUT), |
| }; |
| #undef REQ_OP_NAME |
| |
| /** |
| * blk_op_str - Return string XXX in the REQ_OP_XXX. |
| * @op: REQ_OP_XXX. |
| * |
| * Description: Centralize block layer function to convert REQ_OP_XXX into |
| * string format. Useful in the debugging and tracing bio or request. For |
| * invalid REQ_OP_XXX it returns string "UNKNOWN". |
| */ |
| inline const char *blk_op_str(enum req_op op) |
| { |
| const char *op_str = "UNKNOWN"; |
| |
| if (op < ARRAY_SIZE(blk_op_name) && blk_op_name[op]) |
| op_str = blk_op_name[op]; |
| |
| return op_str; |
| } |
| EXPORT_SYMBOL_GPL(blk_op_str); |
| |
| static const struct { |
| int errno; |
| const char *name; |
| } blk_errors[] = { |
| [BLK_STS_OK] = { 0, "" }, |
| [BLK_STS_NOTSUPP] = { -EOPNOTSUPP, "operation not supported" }, |
| [BLK_STS_TIMEOUT] = { -ETIMEDOUT, "timeout" }, |
| [BLK_STS_NOSPC] = { -ENOSPC, "critical space allocation" }, |
| [BLK_STS_TRANSPORT] = { -ENOLINK, "recoverable transport" }, |
| [BLK_STS_TARGET] = { -EREMOTEIO, "critical target" }, |
| [BLK_STS_NEXUS] = { -EBADE, "critical nexus" }, |
| [BLK_STS_MEDIUM] = { -ENODATA, "critical medium" }, |
| [BLK_STS_PROTECTION] = { -EILSEQ, "protection" }, |
| [BLK_STS_RESOURCE] = { -ENOMEM, "kernel resource" }, |
| [BLK_STS_DEV_RESOURCE] = { -EBUSY, "device resource" }, |
| [BLK_STS_AGAIN] = { -EAGAIN, "nonblocking retry" }, |
| [BLK_STS_OFFLINE] = { -ENODEV, "device offline" }, |
| |
| /* device mapper special case, should not leak out: */ |
| [BLK_STS_DM_REQUEUE] = { -EREMCHG, "dm internal retry" }, |
| |
| /* zone device specific errors */ |
| [BLK_STS_ZONE_OPEN_RESOURCE] = { -ETOOMANYREFS, "open zones exceeded" }, |
| [BLK_STS_ZONE_ACTIVE_RESOURCE] = { -EOVERFLOW, "active zones exceeded" }, |
| |
| /* everything else not covered above: */ |
| [BLK_STS_IOERR] = { -EIO, "I/O" }, |
| }; |
| |
| blk_status_t errno_to_blk_status(int errno) |
| { |
| int i; |
| |
| for (i = 0; i < ARRAY_SIZE(blk_errors); i++) { |
| if (blk_errors[i].errno == errno) |
| return (__force blk_status_t)i; |
| } |
| |
| return BLK_STS_IOERR; |
| } |
| EXPORT_SYMBOL_GPL(errno_to_blk_status); |
| |
| int blk_status_to_errno(blk_status_t status) |
| { |
| int idx = (__force int)status; |
| |
| if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
| return -EIO; |
| return blk_errors[idx].errno; |
| } |
| EXPORT_SYMBOL_GPL(blk_status_to_errno); |
| |
| const char *blk_status_to_str(blk_status_t status) |
| { |
| int idx = (__force int)status; |
| |
| if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) |
| return "<null>"; |
| return blk_errors[idx].name; |
| } |
| |
| /** |
| * blk_sync_queue - cancel any pending callbacks on a queue |
| * @q: the queue |
| * |
| * Description: |
| * The block layer may perform asynchronous callback activity |
| * on a queue, such as calling the unplug function after a timeout. |
| * A block device may call blk_sync_queue to ensure that any |
| * such activity is cancelled, thus allowing it to release resources |
| * that the callbacks might use. The caller must already have made sure |
| * that its ->submit_bio will not re-add plugging prior to calling |
| * this function. |
| * |
| * This function does not cancel any asynchronous activity arising |
| * out of elevator or throttling code. That would require elevator_exit() |
| * and blkcg_exit_queue() to be called with queue lock initialized. |
| * |
| */ |
| void blk_sync_queue(struct request_queue *q) |
| { |
| del_timer_sync(&q->timeout); |
| cancel_work_sync(&q->timeout_work); |
| } |
| EXPORT_SYMBOL(blk_sync_queue); |
| |
| /** |
| * blk_set_pm_only - increment pm_only counter |
| * @q: request queue pointer |
| */ |
| void blk_set_pm_only(struct request_queue *q) |
| { |
| atomic_inc(&q->pm_only); |
| } |
| EXPORT_SYMBOL_GPL(blk_set_pm_only); |
| |
| void blk_clear_pm_only(struct request_queue *q) |
| { |
| int pm_only; |
| |
| pm_only = atomic_dec_return(&q->pm_only); |
| WARN_ON_ONCE(pm_only < 0); |
| if (pm_only == 0) |
| wake_up_all(&q->mq_freeze_wq); |
| } |
| EXPORT_SYMBOL_GPL(blk_clear_pm_only); |
| |
| /** |
| * blk_put_queue - decrement the request_queue refcount |
| * @q: the request_queue structure to decrement the refcount for |
| * |
| * Decrements the refcount of the request_queue kobject. When this reaches 0 |
| * we'll have blk_release_queue() called. |
| * |
| * Context: Any context, but the last reference must not be dropped from |
| * atomic context. |
| */ |
| void blk_put_queue(struct request_queue *q) |
| { |
| kobject_put(&q->kobj); |
| } |
| EXPORT_SYMBOL(blk_put_queue); |
| |
| void blk_queue_start_drain(struct request_queue *q) |
| { |
| /* |
| * When queue DYING flag is set, we need to block new req |
| * entering queue, so we call blk_freeze_queue_start() to |
| * prevent I/O from crossing blk_queue_enter(). |
| */ |
| blk_freeze_queue_start(q); |
| if (queue_is_mq(q)) |
| blk_mq_wake_waiters(q); |
| /* Make blk_queue_enter() reexamine the DYING flag. */ |
| wake_up_all(&q->mq_freeze_wq); |
| } |
| |
| /** |
| * blk_queue_enter() - try to increase q->q_usage_counter |
| * @q: request queue pointer |
| * @flags: BLK_MQ_REQ_NOWAIT and/or BLK_MQ_REQ_PM |
| */ |
| int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) |
| { |
| const bool pm = flags & BLK_MQ_REQ_PM; |
| |
| while (!blk_try_enter_queue(q, pm)) { |
| if (flags & BLK_MQ_REQ_NOWAIT) |
| return -EAGAIN; |
| |
| /* |
| * read pair of barrier in blk_freeze_queue_start(), we need to |
| * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and |
| * reading .mq_freeze_depth or queue dying flag, otherwise the |
| * following wait may never return if the two reads are |
| * reordered. |
| */ |
| smp_rmb(); |
| wait_event(q->mq_freeze_wq, |
| (!q->mq_freeze_depth && |
| blk_pm_resume_queue(pm, q)) || |
| blk_queue_dying(q)); |
| if (blk_queue_dying(q)) |
| return -ENODEV; |
| } |
| |
| return 0; |
| } |
| |
| int __bio_queue_enter(struct request_queue *q, struct bio *bio) |
| { |
| while (!blk_try_enter_queue(q, false)) { |
| struct gendisk *disk = bio->bi_bdev->bd_disk; |
| |
| if (bio->bi_opf & REQ_NOWAIT) { |
| if (test_bit(GD_DEAD, &disk->state)) |
| goto dead; |
| bio_wouldblock_error(bio); |
| return -EAGAIN; |
| } |
| |
| /* |
| * read pair of barrier in blk_freeze_queue_start(), we need to |
| * order reading __PERCPU_REF_DEAD flag of .q_usage_counter and |
| * reading .mq_freeze_depth or queue dying flag, otherwise the |
| * following wait may never return if the two reads are |
| * reordered. |
| */ |
| smp_rmb(); |
| wait_event(q->mq_freeze_wq, |
| (!q->mq_freeze_depth && |
| blk_pm_resume_queue(false, q)) || |
| test_bit(GD_DEAD, &disk->state)); |
| if (test_bit(GD_DEAD, &disk->state)) |
| goto dead; |
| } |
| |
| return 0; |
| dead: |
| bio_io_error(bio); |
| return -ENODEV; |
| } |
| |
| void blk_queue_exit(struct request_queue *q) |
| { |
| percpu_ref_put(&q->q_usage_counter); |
| } |
| |
| static void blk_queue_usage_counter_release(struct percpu_ref *ref) |
| { |
| struct request_queue *q = |
| container_of(ref, struct request_queue, q_usage_counter); |
| |
| wake_up_all(&q->mq_freeze_wq); |
| } |
| |
| static void blk_rq_timed_out_timer(struct timer_list *t) |
| { |
| struct request_queue *q = from_timer(q, t, timeout); |
| |
| kblockd_schedule_work(&q->timeout_work); |
| } |
| |
| static void blk_timeout_work(struct work_struct *work) |
| { |
| } |
| |
| struct request_queue *blk_alloc_queue(int node_id, bool alloc_srcu) |
| { |
| struct request_queue *q; |
| |
| q = kmem_cache_alloc_node(blk_get_queue_kmem_cache(alloc_srcu), |
| GFP_KERNEL | __GFP_ZERO, node_id); |
| if (!q) |
| return NULL; |
| |
| if (alloc_srcu) { |
| blk_queue_flag_set(QUEUE_FLAG_HAS_SRCU, q); |
| if (init_srcu_struct(q->srcu) != 0) |
| goto fail_q; |
| } |
| |
| q->last_merge = NULL; |
| |
| q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL); |
| if (q->id < 0) |
| goto fail_srcu; |
| |
| q->stats = blk_alloc_queue_stats(); |
| if (!q->stats) |
| goto fail_id; |
| |
| q->node = node_id; |
| |
| atomic_set(&q->nr_active_requests_shared_tags, 0); |
| |
| timer_setup(&q->timeout, blk_rq_timed_out_timer, 0); |
| INIT_WORK(&q->timeout_work, blk_timeout_work); |
| INIT_LIST_HEAD(&q->icq_list); |
| |
| kobject_init(&q->kobj, &blk_queue_ktype); |
| |
| mutex_init(&q->debugfs_mutex); |
| mutex_init(&q->sysfs_lock); |
| mutex_init(&q->sysfs_dir_lock); |
| spin_lock_init(&q->queue_lock); |
| |
| init_waitqueue_head(&q->mq_freeze_wq); |
| mutex_init(&q->mq_freeze_lock); |
| |
| /* |
| * Init percpu_ref in atomic mode so that it's faster to shutdown. |
| * See blk_register_queue() for details. |
| */ |
| if (percpu_ref_init(&q->q_usage_counter, |
| blk_queue_usage_counter_release, |
| PERCPU_REF_INIT_ATOMIC, GFP_KERNEL)) |
| goto fail_stats; |
| |
| blk_set_default_limits(&q->limits); |
| q->nr_requests = BLKDEV_DEFAULT_RQ; |
| |
| return q; |
| |
| fail_stats: |
| blk_free_queue_stats(q->stats); |
| fail_id: |
| ida_free(&blk_queue_ida, q->id); |
| fail_srcu: |
| if (alloc_srcu) |
| cleanup_srcu_struct(q->srcu); |
| fail_q: |
| kmem_cache_free(blk_get_queue_kmem_cache(alloc_srcu), q); |
| return NULL; |
| } |
| |
| /** |
| * blk_get_queue - increment the request_queue refcount |
| * @q: the request_queue structure to increment the refcount for |
| * |
| * Increment the refcount of the request_queue kobject. |
| * |
| * Context: Any context. |
| */ |
| bool blk_get_queue(struct request_queue *q) |
| { |
| if (unlikely(blk_queue_dying(q))) |
| return false; |
| kobject_get(&q->kobj); |
| return true; |
| } |
| EXPORT_SYMBOL(blk_get_queue); |
| |
| #ifdef CONFIG_FAIL_MAKE_REQUEST |
| |
| static DECLARE_FAULT_ATTR(fail_make_request); |
| |
| static int __init setup_fail_make_request(char *str) |
| { |
| return setup_fault_attr(&fail_make_request, str); |
| } |
| __setup("fail_make_request=", setup_fail_make_request); |
| |
| bool should_fail_request(struct block_device *part, unsigned int bytes) |
| { |
| return part->bd_make_it_fail && should_fail(&fail_make_request, bytes); |
| } |
| |
| static int __init fail_make_request_debugfs(void) |
| { |
| struct dentry *dir = fault_create_debugfs_attr("fail_make_request", |
| NULL, &fail_make_request); |
| |
| return PTR_ERR_OR_ZERO(dir); |
| } |
| |
| late_initcall(fail_make_request_debugfs); |
| #endif /* CONFIG_FAIL_MAKE_REQUEST */ |
| |
| static inline void bio_check_ro(struct bio *bio) |
| { |
| if (op_is_write(bio_op(bio)) && bdev_read_only(bio->bi_bdev)) { |
| if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) |
| return; |
| pr_warn_ratelimited("Trying to write to read-only block-device %pg\n", |
| bio->bi_bdev); |
| /* Older lvm-tools actually trigger this */ |
| } |
| } |
| |
| static noinline int should_fail_bio(struct bio *bio) |
| { |
| if (should_fail_request(bdev_whole(bio->bi_bdev), bio->bi_iter.bi_size)) |
| return -EIO; |
| return 0; |
| } |
| ALLOW_ERROR_INJECTION(should_fail_bio, ERRNO); |
| |
| /* |
| * Check whether this bio extends beyond the end of the device or partition. |
| * This may well happen - the kernel calls bread() without checking the size of |
| * the device, e.g., when mounting a file system. |
| */ |
| static inline int bio_check_eod(struct bio *bio) |
| { |
| sector_t maxsector = bdev_nr_sectors(bio->bi_bdev); |
| unsigned int nr_sectors = bio_sectors(bio); |
| |
| if (nr_sectors && maxsector && |
| (nr_sectors > maxsector || |
| bio->bi_iter.bi_sector > maxsector - nr_sectors)) { |
| pr_info_ratelimited("%s: attempt to access beyond end of device\n" |
| "%pg: rw=%d, sector=%llu, nr_sectors = %u limit=%llu\n", |
| current->comm, bio->bi_bdev, bio->bi_opf, |
| bio->bi_iter.bi_sector, nr_sectors, maxsector); |
| return -EIO; |
| } |
| return 0; |
| } |
| |
| /* |
| * Remap block n of partition p to block n+start(p) of the disk. |
| */ |
| static int blk_partition_remap(struct bio *bio) |
| { |
| struct block_device *p = bio->bi_bdev; |
| |
| if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) |
| return -EIO; |
| if (bio_sectors(bio)) { |
| bio->bi_iter.bi_sector += p->bd_start_sect; |
| trace_block_bio_remap(bio, p->bd_dev, |
| bio->bi_iter.bi_sector - |
| p->bd_start_sect); |
| } |
| bio_set_flag(bio, BIO_REMAPPED); |
| return 0; |
| } |
| |
| /* |
| * Check write append to a zoned block device. |
| */ |
| static inline blk_status_t blk_check_zone_append(struct request_queue *q, |
| struct bio *bio) |
| { |
| int nr_sectors = bio_sectors(bio); |
| |
| /* Only applicable to zoned block devices */ |
| if (!bdev_is_zoned(bio->bi_bdev)) |
| return BLK_STS_NOTSUPP; |
| |
| /* The bio sector must point to the start of a sequential zone */ |
| if (bio->bi_iter.bi_sector & (bdev_zone_sectors(bio->bi_bdev) - 1) || |
| !bio_zone_is_seq(bio)) |
| return BLK_STS_IOERR; |
| |
| /* |
| * Not allowed to cross zone boundaries. Otherwise, the BIO will be |
| * split and could result in non-contiguous sectors being written in |
| * different zones. |
| */ |
| if (nr_sectors > q->limits.chunk_sectors) |
| return BLK_STS_IOERR; |
| |
| /* Make sure the BIO is small enough and will not get split */ |
| if (nr_sectors > q->limits.max_zone_append_sectors) |
| return BLK_STS_IOERR; |
| |
| bio->bi_opf |= REQ_NOMERGE; |
| |
| return BLK_STS_OK; |
| } |
| |
| static void __submit_bio(struct bio *bio) |
| { |
| struct gendisk *disk = bio->bi_bdev->bd_disk; |
| |
| if (unlikely(!blk_crypto_bio_prep(&bio))) |
| return; |
| |
| if (!disk->fops->submit_bio) { |
| blk_mq_submit_bio(bio); |
| } else if (likely(bio_queue_enter(bio) == 0)) { |
| disk->fops->submit_bio(bio); |
| blk_queue_exit(disk->queue); |
| } |
| } |
| |
| /* |
| * The loop in this function may be a bit non-obvious, and so deserves some |
| * explanation: |
| * |
| * - Before entering the loop, bio->bi_next is NULL (as all callers ensure |
| * that), so we have a list with a single bio. |
| * - We pretend that we have just taken it off a longer list, so we assign |
| * bio_list to a pointer to the bio_list_on_stack, thus initialising the |
| * bio_list of new bios to be added. ->submit_bio() may indeed add some more |
| * bios through a recursive call to submit_bio_noacct. If it did, we find a |
| * non-NULL value in bio_list and re-enter the loop from the top. |
| * - In this case we really did just take the bio of the top of the list (no |
| * pretending) and so remove it from bio_list, and call into ->submit_bio() |
| * again. |
| * |
| * bio_list_on_stack[0] contains bios submitted by the current ->submit_bio. |
| * bio_list_on_stack[1] contains bios that were submitted before the current |
| * ->submit_bio, but that haven't been processed yet. |
| */ |
| static void __submit_bio_noacct(struct bio *bio) |
| { |
| struct bio_list bio_list_on_stack[2]; |
| |
| BUG_ON(bio->bi_next); |
| |
| bio_list_init(&bio_list_on_stack[0]); |
| current->bio_list = bio_list_on_stack; |
| |
| do { |
| struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
| struct bio_list lower, same; |
| |
| /* |
| * Create a fresh bio_list for all subordinate requests. |
| */ |
| bio_list_on_stack[1] = bio_list_on_stack[0]; |
| bio_list_init(&bio_list_on_stack[0]); |
| |
| __submit_bio(bio); |
| |
| /* |
| * Sort new bios into those for a lower level and those for the |
| * same level. |
| */ |
| bio_list_init(&lower); |
| bio_list_init(&same); |
| while ((bio = bio_list_pop(&bio_list_on_stack[0])) != NULL) |
| if (q == bdev_get_queue(bio->bi_bdev)) |
| bio_list_add(&same, bio); |
| else |
| bio_list_add(&lower, bio); |
| |
| /* |
| * Now assemble so we handle the lowest level first. |
| */ |
| bio_list_merge(&bio_list_on_stack[0], &lower); |
| bio_list_merge(&bio_list_on_stack[0], &same); |
| bio_list_merge(&bio_list_on_stack[0], &bio_list_on_stack[1]); |
| } while ((bio = bio_list_pop(&bio_list_on_stack[0]))); |
| |
| current->bio_list = NULL; |
| } |
| |
| static void __submit_bio_noacct_mq(struct bio *bio) |
| { |
| struct bio_list bio_list[2] = { }; |
| |
| current->bio_list = bio_list; |
| |
| do { |
| __submit_bio(bio); |
| } while ((bio = bio_list_pop(&bio_list[0]))); |
| |
| current->bio_list = NULL; |
| } |
| |
| void submit_bio_noacct_nocheck(struct bio *bio) |
| { |
| blk_cgroup_bio_start(bio); |
| blkcg_bio_issue_init(bio); |
| |
| if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { |
| trace_block_bio_queue(bio); |
| /* |
| * Now that enqueuing has been traced, we need to trace |
| * completion as well. |
| */ |
| bio_set_flag(bio, BIO_TRACE_COMPLETION); |
| } |
| |
| /* |
| * We only want one ->submit_bio to be active at a time, else stack |
| * usage with stacked devices could be a problem. Use current->bio_list |
| * to collect a list of requests submited by a ->submit_bio method while |
| * it is active, and then process them after it returned. |
| */ |
| if (current->bio_list) |
| bio_list_add(¤t->bio_list[0], bio); |
| else if (!bio->bi_bdev->bd_disk->fops->submit_bio) |
| __submit_bio_noacct_mq(bio); |
| else |
| __submit_bio_noacct(bio); |
| } |
| |
| /** |
| * submit_bio_noacct - re-submit a bio to the block device layer for I/O |
| * @bio: The bio describing the location in memory and on the device. |
| * |
| * This is a version of submit_bio() that shall only be used for I/O that is |
| * resubmitted to lower level drivers by stacking block drivers. All file |
| * systems and other upper level users of the block layer should use |
| * submit_bio() instead. |
| */ |
| void submit_bio_noacct(struct bio *bio) |
| { |
| struct block_device *bdev = bio->bi_bdev; |
| struct request_queue *q = bdev_get_queue(bdev); |
| blk_status_t status = BLK_STS_IOERR; |
| struct blk_plug *plug; |
| |
| might_sleep(); |
| |
| plug = blk_mq_plug(bio); |
| if (plug && plug->nowait) |
| bio->bi_opf |= REQ_NOWAIT; |
| |
| /* |
| * For a REQ_NOWAIT based request, return -EOPNOTSUPP |
| * if queue does not support NOWAIT. |
| */ |
| if ((bio->bi_opf & REQ_NOWAIT) && !bdev_nowait(bdev)) |
| goto not_supported; |
| |
| if (should_fail_bio(bio)) |
| goto end_io; |
| bio_check_ro(bio); |
| if (!bio_flagged(bio, BIO_REMAPPED)) { |
| if (unlikely(bio_check_eod(bio))) |
| goto end_io; |
| if (bdev->bd_partno && unlikely(blk_partition_remap(bio))) |
| goto end_io; |
| } |
| |
| /* |
| * Filter flush bio's early so that bio based drivers without flush |
| * support don't have to worry about them. |
| */ |
| if (op_is_flush(bio->bi_opf) && |
| !test_bit(QUEUE_FLAG_WC, &q->queue_flags)) { |
| bio->bi_opf &= ~(REQ_PREFLUSH | REQ_FUA); |
| if (!bio_sectors(bio)) { |
| status = BLK_STS_OK; |
| goto end_io; |
| } |
| } |
| |
| if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
| bio_clear_polled(bio); |
| |
| switch (bio_op(bio)) { |
| case REQ_OP_DISCARD: |
| if (!bdev_max_discard_sectors(bdev)) |
| goto not_supported; |
| break; |
| case REQ_OP_SECURE_ERASE: |
| if (!bdev_max_secure_erase_sectors(bdev)) |
| goto not_supported; |
| break; |
| case REQ_OP_ZONE_APPEND: |
| status = blk_check_zone_append(q, bio); |
| if (status != BLK_STS_OK) |
| goto end_io; |
| break; |
| case REQ_OP_ZONE_RESET: |
| case REQ_OP_ZONE_OPEN: |
| case REQ_OP_ZONE_CLOSE: |
| case REQ_OP_ZONE_FINISH: |
| if (!bdev_is_zoned(bio->bi_bdev)) |
| goto not_supported; |
| break; |
| case REQ_OP_ZONE_RESET_ALL: |
| if (!bdev_is_zoned(bio->bi_bdev) || !blk_queue_zone_resetall(q)) |
| goto not_supported; |
| break; |
| case REQ_OP_WRITE_ZEROES: |
| if (!q->limits.max_write_zeroes_sectors) |
| goto not_supported; |
| break; |
| default: |
| break; |
| } |
| |
| if (blk_throtl_bio(bio)) |
| return; |
| submit_bio_noacct_nocheck(bio); |
| return; |
| |
| not_supported: |
| status = BLK_STS_NOTSUPP; |
| end_io: |
| bio->bi_status = status; |
| bio_endio(bio); |
| } |
| EXPORT_SYMBOL(submit_bio_noacct); |
| |
| /** |
| * submit_bio - submit a bio to the block device layer for I/O |
| * @bio: The &struct bio which describes the I/O |
| * |
| * submit_bio() is used to submit I/O requests to block devices. It is passed a |
| * fully set up &struct bio that describes the I/O that needs to be done. The |
| * bio will be send to the device described by the bi_bdev field. |
| * |
| * The success/failure status of the request, along with notification of |
| * completion, is delivered asynchronously through the ->bi_end_io() callback |
| * in @bio. The bio must NOT be touched by the caller until ->bi_end_io() has |
| * been called. |
| */ |
| void submit_bio(struct bio *bio) |
| { |
| if (blkcg_punt_bio_submit(bio)) |
| return; |
| |
| if (bio_op(bio) == REQ_OP_READ) { |
| task_io_account_read(bio->bi_iter.bi_size); |
| count_vm_events(PGPGIN, bio_sectors(bio)); |
| } else if (bio_op(bio) == REQ_OP_WRITE) { |
| count_vm_events(PGPGOUT, bio_sectors(bio)); |
| } |
| |
| submit_bio_noacct(bio); |
| } |
| EXPORT_SYMBOL(submit_bio); |
| |
| /** |
| * bio_poll - poll for BIO completions |
| * @bio: bio to poll for |
| * @iob: batches of IO |
| * @flags: BLK_POLL_* flags that control the behavior |
| * |
| * Poll for completions on queue associated with the bio. Returns number of |
| * completed entries found. |
| * |
| * Note: the caller must either be the context that submitted @bio, or |
| * be in a RCU critical section to prevent freeing of @bio. |
| */ |
| int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags) |
| { |
| blk_qc_t cookie = READ_ONCE(bio->bi_cookie); |
| struct block_device *bdev; |
| struct request_queue *q; |
| int ret = 0; |
| |
| bdev = READ_ONCE(bio->bi_bdev); |
| if (!bdev) |
| return 0; |
| |
| q = bdev_get_queue(bdev); |
| if (cookie == BLK_QC_T_NONE || |
| !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
| return 0; |
| |
| /* |
| * As the requests that require a zone lock are not plugged in the |
| * first place, directly accessing the plug instead of using |
| * blk_mq_plug() should not have any consequences during flushing for |
| * zoned devices. |
| */ |
| blk_flush_plug(current->plug, false); |
| |
| /* |
| * We need to be able to enter a frozen queue, similar to how |
| * timeouts also need to do that. If that is blocked, then we can |
| * have pending IO when a queue freeze is started, and then the |
| * wait for the freeze to finish will wait for polled requests to |
| * timeout as the poller is preventer from entering the queue and |
| * completing them. As long as we prevent new IO from being queued, |
| * that should be all that matters. |
| */ |
| if (!percpu_ref_tryget(&q->q_usage_counter)) |
| return 0; |
| if (queue_is_mq(q)) { |
| ret = blk_mq_poll(q, cookie, iob, flags); |
| } else { |
| struct gendisk *disk = q->disk; |
| |
| if (disk && disk->fops->poll_bio) |
| ret = disk->fops->poll_bio(bio, iob, flags); |
| } |
| blk_queue_exit(q); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(bio_poll); |
| |
| /* |
| * Helper to implement file_operations.iopoll. Requires the bio to be stored |
| * in iocb->private, and cleared before freeing the bio. |
| */ |
| int iocb_bio_iopoll(struct kiocb *kiocb, struct io_comp_batch *iob, |
| unsigned int flags) |
| { |
| struct bio *bio; |
| int ret = 0; |
| |
| /* |
| * Note: the bio cache only uses SLAB_TYPESAFE_BY_RCU, so bio can |
| * point to a freshly allocated bio at this point. If that happens |
| * we have a few cases to consider: |
| * |
| * 1) the bio is beeing initialized and bi_bdev is NULL. We can just |
| * simply nothing in this case |
| * 2) the bio points to a not poll enabled device. bio_poll will catch |
| * this and return 0 |
| * 3) the bio points to a poll capable device, including but not |
| * limited to the one that the original bio pointed to. In this |
| * case we will call into the actual poll method and poll for I/O, |
| * even if we don't need to, but it won't cause harm either. |
| * |
| * For cases 2) and 3) above the RCU grace period ensures that bi_bdev |
| * is still allocated. Because partitions hold a reference to the whole |
| * device bdev and thus disk, the disk is also still valid. Grabbing |
| * a reference to the queue in bio_poll() ensures the hctxs and requests |
| * are still valid as well. |
| */ |
| rcu_read_lock(); |
| bio = READ_ONCE(kiocb->private); |
| if (bio) |
| ret = bio_poll(bio, iob, flags); |
| rcu_read_unlock(); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(iocb_bio_iopoll); |
| |
| void update_io_ticks(struct block_device *part, unsigned long now, bool end) |
| { |
| unsigned long stamp; |
| again: |
| stamp = READ_ONCE(part->bd_stamp); |
| if (unlikely(time_after(now, stamp))) { |
| if (likely(try_cmpxchg(&part->bd_stamp, &stamp, now))) |
| __part_stat_add(part, io_ticks, end ? now - stamp : 1); |
| } |
| if (part->bd_partno) { |
| part = bdev_whole(part); |
| goto again; |
| } |
| } |
| |
| unsigned long bdev_start_io_acct(struct block_device *bdev, |
| unsigned int sectors, enum req_op op, |
| unsigned long start_time) |
| { |
| const int sgrp = op_stat_group(op); |
| |
| part_stat_lock(); |
| update_io_ticks(bdev, start_time, false); |
| part_stat_inc(bdev, ios[sgrp]); |
| part_stat_add(bdev, sectors[sgrp], sectors); |
| part_stat_local_inc(bdev, in_flight[op_is_write(op)]); |
| part_stat_unlock(); |
| |
| return start_time; |
| } |
| EXPORT_SYMBOL(bdev_start_io_acct); |
| |
| /** |
| * bio_start_io_acct_time - start I/O accounting for bio based drivers |
| * @bio: bio to start account for |
| * @start_time: start time that should be passed back to bio_end_io_acct(). |
| */ |
| void bio_start_io_acct_time(struct bio *bio, unsigned long start_time) |
| { |
| bdev_start_io_acct(bio->bi_bdev, bio_sectors(bio), |
| bio_op(bio), start_time); |
| } |
| EXPORT_SYMBOL_GPL(bio_start_io_acct_time); |
| |
| /** |
| * bio_start_io_acct - start I/O accounting for bio based drivers |
| * @bio: bio to start account for |
| * |
| * Returns the start time that should be passed back to bio_end_io_acct(). |
| */ |
| unsigned long bio_start_io_acct(struct bio *bio) |
| { |
| return bdev_start_io_acct(bio->bi_bdev, bio_sectors(bio), |
| bio_op(bio), jiffies); |
| } |
| EXPORT_SYMBOL_GPL(bio_start_io_acct); |
| |
| void bdev_end_io_acct(struct block_device *bdev, enum req_op op, |
| unsigned long start_time) |
| { |
| const int sgrp = op_stat_group(op); |
| unsigned long now = READ_ONCE(jiffies); |
| unsigned long duration = now - start_time; |
| |
| part_stat_lock(); |
| update_io_ticks(bdev, now, true); |
| part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration)); |
| part_stat_local_dec(bdev, in_flight[op_is_write(op)]); |
| part_stat_unlock(); |
| } |
| EXPORT_SYMBOL(bdev_end_io_acct); |
| |
| void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time, |
| struct block_device *orig_bdev) |
| { |
| bdev_end_io_acct(orig_bdev, bio_op(bio), start_time); |
| } |
| EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped); |
| |
| /** |
| * blk_lld_busy - Check if underlying low-level drivers of a device are busy |
| * @q : the queue of the device being checked |
| * |
| * Description: |
| * Check if underlying low-level drivers of a device are busy. |
| * If the drivers want to export their busy state, they must set own |
| * exporting function using blk_queue_lld_busy() first. |
| * |
| * Basically, this function is used only by request stacking drivers |
| * to stop dispatching requests to underlying devices when underlying |
| * devices are busy. This behavior helps more I/O merging on the queue |
| * of the request stacking driver and prevents I/O throughput regression |
| * on burst I/O load. |
| * |
| * Return: |
| * 0 - Not busy (The request stacking driver should dispatch request) |
| * 1 - Busy (The request stacking driver should stop dispatching request) |
| */ |
| int blk_lld_busy(struct request_queue *q) |
| { |
| if (queue_is_mq(q) && q->mq_ops->busy) |
| return q->mq_ops->busy(q); |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(blk_lld_busy); |
| |
| int kblockd_schedule_work(struct work_struct *work) |
| { |
| return queue_work(kblockd_workqueue, work); |
| } |
| EXPORT_SYMBOL(kblockd_schedule_work); |
| |
| int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, |
| unsigned long delay) |
| { |
| return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); |
| } |
| EXPORT_SYMBOL(kblockd_mod_delayed_work_on); |
| |
| void blk_start_plug_nr_ios(struct blk_plug *plug, unsigned short nr_ios) |
| { |
| struct task_struct *tsk = current; |
| |
| /* |
| * If this is a nested plug, don't actually assign it. |
| */ |
| if (tsk->plug) |
| return; |
| |
| plug->mq_list = NULL; |
| plug->cached_rq = NULL; |
| plug->nr_ios = min_t(unsigned short, nr_ios, BLK_MAX_REQUEST_COUNT); |
| plug->rq_count = 0; |
| plug->multiple_queues = false; |
| plug->has_elevator = false; |
| plug->nowait = false; |
| INIT_LIST_HEAD(&plug->cb_list); |
| |
| /* |
| * Store ordering should not be needed here, since a potential |
| * preempt will imply a full memory barrier |
| */ |
| tsk->plug = plug; |
| } |
| |
| /** |
| * blk_start_plug - initialize blk_plug and track it inside the task_struct |
| * @plug: The &struct blk_plug that needs to be initialized |
| * |
| * Description: |
| * blk_start_plug() indicates to the block layer an intent by the caller |
| * to submit multiple I/O requests in a batch. The block layer may use |
| * this hint to defer submitting I/Os from the caller until blk_finish_plug() |
| * is called. However, the block layer may choose to submit requests |
| * before a call to blk_finish_plug() if the number of queued I/Os |
| * exceeds %BLK_MAX_REQUEST_COUNT, or if the size of the I/O is larger than |
| * %BLK_PLUG_FLUSH_SIZE. The queued I/Os may also be submitted early if |
| * the task schedules (see below). |
| * |
| * Tracking blk_plug inside the task_struct will help with auto-flushing the |
| * pending I/O should the task end up blocking between blk_start_plug() and |
| * blk_finish_plug(). This is important from a performance perspective, but |
| * also ensures that we don't deadlock. For instance, if the task is blocking |
| * for a memory allocation, memory reclaim could end up wanting to free a |
| * page belonging to that request that is currently residing in our private |
| * plug. By flushing the pending I/O when the process goes to sleep, we avoid |
| * this kind of deadlock. |
| */ |
| void blk_start_plug(struct blk_plug *plug) |
| { |
| blk_start_plug_nr_ios(plug, 1); |
| } |
| EXPORT_SYMBOL(blk_start_plug); |
| |
| static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) |
| { |
| LIST_HEAD(callbacks); |
| |
| while (!list_empty(&plug->cb_list)) { |
| list_splice_init(&plug->cb_list, &callbacks); |
| |
| while (!list_empty(&callbacks)) { |
| struct blk_plug_cb *cb = list_first_entry(&callbacks, |
| struct blk_plug_cb, |
| list); |
| list_del(&cb->list); |
| cb->callback(cb, from_schedule); |
| } |
| } |
| } |
| |
| struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, |
| int size) |
| { |
| struct blk_plug *plug = current->plug; |
| struct blk_plug_cb *cb; |
| |
| if (!plug) |
| return NULL; |
| |
| list_for_each_entry(cb, &plug->cb_list, list) |
| if (cb->callback == unplug && cb->data == data) |
| return cb; |
| |
| /* Not currently on the callback list */ |
| BUG_ON(size < sizeof(*cb)); |
| cb = kzalloc(size, GFP_ATOMIC); |
| if (cb) { |
| cb->data = data; |
| cb->callback = unplug; |
| list_add(&cb->list, &plug->cb_list); |
| } |
| return cb; |
| } |
| EXPORT_SYMBOL(blk_check_plugged); |
| |
| void __blk_flush_plug(struct blk_plug *plug, bool from_schedule) |
| { |
| if (!list_empty(&plug->cb_list)) |
| flush_plug_callbacks(plug, from_schedule); |
| blk_mq_flush_plug_list(plug, from_schedule); |
| /* |
| * Unconditionally flush out cached requests, even if the unplug |
| * event came from schedule. Since we know hold references to the |
| * queue for cached requests, we don't want a blocked task holding |
| * up a queue freeze/quiesce event. |
| */ |
| if (unlikely(!rq_list_empty(plug->cached_rq))) |
| blk_mq_free_plug_rqs(plug); |
| } |
| |
| /** |
| * blk_finish_plug - mark the end of a batch of submitted I/O |
| * @plug: The &struct blk_plug passed to blk_start_plug() |
| * |
| * Description: |
| * Indicate that a batch of I/O submissions is complete. This function |
| * must be paired with an initial call to blk_start_plug(). The intent |
| * is to allow the block layer to optimize I/O submission. See the |
| * documentation for blk_start_plug() for more information. |
| */ |
| void blk_finish_plug(struct blk_plug *plug) |
| { |
| if (plug == current->plug) { |
| __blk_flush_plug(plug, false); |
| current->plug = NULL; |
| } |
| } |
| EXPORT_SYMBOL(blk_finish_plug); |
| |
| void blk_io_schedule(void) |
| { |
| /* Prevent hang_check timer from firing at us during very long I/O */ |
| unsigned long timeout = sysctl_hung_task_timeout_secs * HZ / 2; |
| |
| if (timeout) |
| io_schedule_timeout(timeout); |
| else |
| io_schedule(); |
| } |
| EXPORT_SYMBOL_GPL(blk_io_schedule); |
| |
| int __init blk_dev_init(void) |
| { |
| BUILD_BUG_ON((__force u32)REQ_OP_LAST >= (1 << REQ_OP_BITS)); |
| BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
| sizeof_field(struct request, cmd_flags)); |
| BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
| sizeof_field(struct bio, bi_opf)); |
| BUILD_BUG_ON(ALIGN(offsetof(struct request_queue, srcu), |
| __alignof__(struct request_queue)) != |
| sizeof(struct request_queue)); |
| |
| /* used for unplugging and affects IO latency/throughput - HIGHPRI */ |
| kblockd_workqueue = alloc_workqueue("kblockd", |
| WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); |
| if (!kblockd_workqueue) |
| panic("Failed to create kblockd\n"); |
| |
| blk_requestq_cachep = kmem_cache_create("request_queue", |
| sizeof(struct request_queue), 0, SLAB_PANIC, NULL); |
| |
| blk_requestq_srcu_cachep = kmem_cache_create("request_queue_srcu", |
| sizeof(struct request_queue) + |
| sizeof(struct srcu_struct), 0, SLAB_PANIC, NULL); |
| |
| blk_debugfs_root = debugfs_create_dir("block", NULL); |
| |
| return 0; |
| } |