diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-11 08:27:49 +0000 |
commit | ace9429bb58fd418f0c81d4c2835699bddf6bde6 (patch) | |
tree | b2d64bc10158fdd5497876388cd68142ca374ed3 /block/blk-core.c | |
parent | Initial commit. (diff) | |
download | linux-upstream/6.6.15.tar.xz linux-upstream/6.6.15.zip |
Adding upstream version 6.6.15.upstream/6.6.15
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | block/blk-core.c | 1212 |
1 files changed, 1212 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c new file mode 100644 index 0000000000..2eca76ccf4 --- /dev/null +++ b/block/blk-core.c @@ -0,0 +1,1212 @@ +// 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); + +static DEFINE_IDA(blk_queue_ida); + +/* + * For queue allocation + */ +static struct kmem_cache *blk_requestq_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_RESV_CONFLICT] = { -EBADE, "reservation conflict" }, + [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" }, + + /* Command duration limit device-side timeout */ + [BLK_STS_DURATION_LIMIT] = { -ETIME, "duration limit 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; +} +EXPORT_SYMBOL_GPL(blk_status_to_str); + +/** + * 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); + +static void blk_free_queue_rcu(struct rcu_head *rcu_head) +{ + struct request_queue *q = container_of(rcu_head, + struct request_queue, rcu_head); + + percpu_ref_exit(&q->q_usage_counter); + kmem_cache_free(blk_requestq_cachep, q); +} + +static void blk_free_queue(struct request_queue *q) +{ + blk_free_queue_stats(q->stats); + if (queue_is_mq(q)) + blk_mq_release(q); + + ida_free(&blk_queue_ida, q->id); + call_rcu(&q->rcu_head, blk_free_queue_rcu); +} + +/** + * 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 and free it when the refcount + * reaches 0. + */ +void blk_put_queue(struct request_queue *q) +{ + if (refcount_dec_and_test(&q->refs)) + blk_free_queue(q); +} +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) +{ + struct request_queue *q; + + q = kmem_cache_alloc_node(blk_requestq_cachep, GFP_KERNEL | __GFP_ZERO, + node_id); + if (!q) + return NULL; + + q->last_merge = NULL; + + q->id = ida_alloc(&blk_queue_ida, GFP_KERNEL); + if (q->id < 0) + goto fail_q; + + 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); + + refcount_set(&q->refs, 1); + mutex_init(&q->debugfs_mutex); + mutex_init(&q->sysfs_lock); + mutex_init(&q->sysfs_dir_lock); + mutex_init(&q->rq_qos_mutex); + 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_q: + kmem_cache_free(blk_requestq_cachep, 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; + refcount_inc(&q->refs); + 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; + + if (bio->bi_bdev->bd_ro_warned) + return; + + bio->bi_bdev->bd_ro_warned = true; + /* + * Use ioctl to set underlying disk of raid/dm to read-only + * will trigger this. + */ + pr_warn("Trying to write to read-only block-device %pg\n", + bio->bi_bdev); + } +} + +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 && + (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 (!bdev_is_zone_start(bio->bi_bdev, bio->bi_iter.bi_sector) || + !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) +{ + if (unlikely(!blk_crypto_bio_prep(&bio))) + return; + + if (!bio->bi_bdev->bd_has_submit_bio) { + blk_mq_submit_bio(bio); + } else if (likely(bio_queue_enter(bio) == 0)) { + struct gendisk *disk = bio->bi_bdev->bd_disk; + + 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_has_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; + + might_sleep(); + + /* + * 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)) { + if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_WRITE && + bio_op(bio) != REQ_OP_ZONE_APPEND)) + goto end_io; + if (!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 (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, enum req_op op, + unsigned long start_time) +{ + part_stat_lock(); + update_io_ticks(bdev, start_time, false); + 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 - 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_op(bio), jiffies); +} +EXPORT_SYMBOL_GPL(bio_start_io_acct); + +void bdev_end_io_acct(struct block_device *bdev, enum req_op op, + unsigned int sectors, 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_inc(bdev, ios[sgrp]); + part_stat_add(bdev, sectors[sgrp], sectors); + 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), bio_sectors(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; + 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)); + + /* 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_debugfs_root = debugfs_create_dir("block", NULL); + + return 0; +} |