diff options
Diffstat (limited to 'block/blk-core.c')
| -rw-r--r-- | block/blk-core.c | 1816 |
1 files changed, 1816 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c new file mode 100644 index 000000000..e5eeec801 --- /dev/null +++ b/block/blk-core.c @@ -0,0 +1,1816 @@ +// 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/backing-dev.h> +#include <linux/bio.h> +#include <linux/blkdev.h> +#include <linux/blk-mq.h> +#include <linux/blk-pm.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/blk-cgroup.h> +#include <linux/t10-pi.h> +#include <linux/debugfs.h> +#include <linux/bpf.h> +#include <linux/psi.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.h" +#include "blk-mq-sched.h" +#include "blk-pm.h" +#include "blk-rq-qos.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); + +DEFINE_IDA(blk_queue_ida); + +/* + * For queue allocation + */ +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); + +void blk_rq_init(struct request_queue *q, struct request *rq) +{ + memset(rq, 0, sizeof(*rq)); + + INIT_LIST_HEAD(&rq->queuelist); + rq->q = q; + rq->__sector = (sector_t) -1; + INIT_HLIST_NODE(&rq->hash); + RB_CLEAR_NODE(&rq->rb_node); + rq->tag = BLK_MQ_NO_TAG; + rq->internal_tag = BLK_MQ_NO_TAG; + rq->start_time_ns = ktime_get_ns(); + rq->part = NULL; + blk_crypto_rq_set_defaults(rq); +} +EXPORT_SYMBOL(blk_rq_init); + +#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_SAME), + REQ_OP_NAME(WRITE_ZEROES), + REQ_OP_NAME(SCSI_IN), + REQ_OP_NAME(SCSI_OUT), + 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(unsigned int 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" }, + + /* 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); + +static void print_req_error(struct request *req, blk_status_t status, + const char *caller) +{ + int idx = (__force int)status; + + if (WARN_ON_ONCE(idx >= ARRAY_SIZE(blk_errors))) + return; + + printk_ratelimited(KERN_ERR + "%s: %s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x " + "phys_seg %u prio class %u\n", + caller, blk_errors[idx].name, + req->rq_disk ? req->rq_disk->disk_name : "?", + blk_rq_pos(req), req_op(req), blk_op_str(req_op(req)), + req->cmd_flags & ~REQ_OP_MASK, + req->nr_phys_segments, + IOPRIO_PRIO_CLASS(req->ioprio)); +} + +static void req_bio_endio(struct request *rq, struct bio *bio, + unsigned int nbytes, blk_status_t error) +{ + if (error) + bio->bi_status = error; + + if (unlikely(rq->rq_flags & RQF_QUIET)) + bio_set_flag(bio, BIO_QUIET); + + bio_advance(bio, nbytes); + + if (req_op(rq) == REQ_OP_ZONE_APPEND && error == BLK_STS_OK) { + /* + * Partial zone append completions cannot be supported as the + * BIO fragments may end up not being written sequentially. + */ + if (bio->bi_iter.bi_size) + bio->bi_status = BLK_STS_IOERR; + else + bio->bi_iter.bi_sector = rq->__sector; + } + + /* don't actually finish bio if it's part of flush sequence */ + if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) + bio_endio(bio); +} + +void blk_dump_rq_flags(struct request *rq, char *msg) +{ + printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg, + rq->rq_disk ? rq->rq_disk->disk_name : "?", + (unsigned long long) rq->cmd_flags); + + printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n", + (unsigned long long)blk_rq_pos(rq), + blk_rq_sectors(rq), blk_rq_cur_sectors(rq)); + printk(KERN_INFO " bio %p, biotail %p, len %u\n", + rq->bio, rq->biotail, blk_rq_bytes(rq)); +} +EXPORT_SYMBOL(blk_dump_rq_flags); + +/** + * 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_set_queue_dying(struct request_queue *q) +{ + blk_queue_flag_set(QUEUE_FLAG_DYING, 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); +} +EXPORT_SYMBOL_GPL(blk_set_queue_dying); + +/** + * blk_cleanup_queue - shutdown a request queue + * @q: request queue to shutdown + * + * Mark @q DYING, drain all pending requests, mark @q DEAD, destroy and + * put it. All future requests will be failed immediately with -ENODEV. + * + * Context: can sleep + */ +void blk_cleanup_queue(struct request_queue *q) +{ + /* cannot be called from atomic context */ + might_sleep(); + + WARN_ON_ONCE(blk_queue_registered(q)); + + /* mark @q DYING, no new request or merges will be allowed afterwards */ + blk_set_queue_dying(q); + + blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); + blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); + + /* + * Drain all requests queued before DYING marking. Set DEAD flag to + * prevent that blk_mq_run_hw_queues() accesses the hardware queues + * after draining finished. + */ + blk_freeze_queue(q); + + rq_qos_exit(q); + + blk_queue_flag_set(QUEUE_FLAG_DEAD, q); + + /* for synchronous bio-based driver finish in-flight integrity i/o */ + blk_flush_integrity(); + + /* @q won't process any more request, flush async actions */ + del_timer_sync(&q->backing_dev_info->laptop_mode_wb_timer); + blk_sync_queue(q); + + if (queue_is_mq(q)) + blk_mq_exit_queue(q); + + /* + * In theory, request pool of sched_tags belongs to request queue. + * However, the current implementation requires tag_set for freeing + * requests, so free the pool now. + * + * Queue has become frozen, there can't be any in-queue requests, so + * it is safe to free requests now. + */ + mutex_lock(&q->sysfs_lock); + if (q->elevator) + blk_mq_sched_free_requests(q); + mutex_unlock(&q->sysfs_lock); + + /* @q is and will stay empty, shutdown and put */ + blk_put_queue(q); +} +EXPORT_SYMBOL(blk_cleanup_queue); + +/** + * 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 (true) { + bool success = false; + + rcu_read_lock(); + if (percpu_ref_tryget_live(&q->q_usage_counter)) { + /* + * The code that increments the pm_only counter is + * responsible for ensuring that that counter is + * globally visible before the queue is unfrozen. + */ + if ((pm && queue_rpm_status(q) != RPM_SUSPENDED) || + !blk_queue_pm_only(q)) { + success = true; + } else { + percpu_ref_put(&q->q_usage_counter); + } + } + rcu_read_unlock(); + + if (success) + return 0; + + if (flags & BLK_MQ_REQ_NOWAIT) + return -EBUSY; + + /* + * 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; + } +} + +static inline int bio_queue_enter(struct bio *bio) +{ + struct request_queue *q = bio->bi_disk->queue; + bool nowait = bio->bi_opf & REQ_NOWAIT; + int ret; + + ret = blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0); + if (unlikely(ret)) { + if (nowait && !blk_queue_dying(q)) + bio_wouldblock_error(bio); + else + bio_io_error(bio); + } + + return ret; +} + +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; + int ret; + + 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_simple_get(&blk_queue_ida, 0, 0, GFP_KERNEL); + if (q->id < 0) + goto fail_q; + + ret = bioset_init(&q->bio_split, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS); + if (ret) + goto fail_id; + + q->backing_dev_info = bdi_alloc(node_id); + if (!q->backing_dev_info) + goto fail_split; + + q->stats = blk_alloc_queue_stats(); + if (!q->stats) + goto fail_stats; + + q->node = node_id; + + atomic_set(&q->nr_active_requests_shared_sbitmap, 0); + + timer_setup(&q->backing_dev_info->laptop_mode_wb_timer, + laptop_mode_timer_fn, 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); +#ifdef CONFIG_BLK_CGROUP + INIT_LIST_HEAD(&q->blkg_list); +#endif + + 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_bdi; + + if (blkcg_init_queue(q)) + goto fail_ref; + + blk_queue_dma_alignment(q, 511); + blk_set_default_limits(&q->limits); + q->nr_requests = BLKDEV_MAX_RQ; + + return q; + +fail_ref: + percpu_ref_exit(&q->q_usage_counter); +fail_bdi: + blk_free_queue_stats(q->stats); +fail_stats: + bdi_put(q->backing_dev_info); +fail_split: + bioset_exit(&q->bio_split); +fail_id: + ida_simple_remove(&blk_queue_ida, q->id); +fail_q: + kmem_cache_free(blk_requestq_cachep, q); + return NULL; +} +EXPORT_SYMBOL(blk_alloc_queue); + +/** + * 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 (likely(!blk_queue_dying(q))) { + __blk_get_queue(q); + return true; + } + + return false; +} +EXPORT_SYMBOL(blk_get_queue); + +/** + * blk_get_request - allocate a request + * @q: request queue to allocate a request for + * @op: operation (REQ_OP_*) and REQ_* flags, e.g. REQ_SYNC. + * @flags: BLK_MQ_REQ_* flags, e.g. BLK_MQ_REQ_NOWAIT. + */ +struct request *blk_get_request(struct request_queue *q, unsigned int op, + blk_mq_req_flags_t flags) +{ + struct request *req; + + WARN_ON_ONCE(op & REQ_NOWAIT); + WARN_ON_ONCE(flags & ~(BLK_MQ_REQ_NOWAIT | BLK_MQ_REQ_PM)); + + req = blk_mq_alloc_request(q, op, flags); + if (!IS_ERR(req) && q->mq_ops->initialize_rq_fn) + q->mq_ops->initialize_rq_fn(req); + + return req; +} +EXPORT_SYMBOL(blk_get_request); + +void blk_put_request(struct request *req) +{ + blk_mq_free_request(req); +} +EXPORT_SYMBOL(blk_put_request); + +static void handle_bad_sector(struct bio *bio, sector_t maxsector) +{ + char b[BDEVNAME_SIZE]; + + pr_info_ratelimited("attempt to access beyond end of device\n" + "%s: rw=%d, want=%llu, limit=%llu\n", + bio_devname(bio, b), bio->bi_opf, + bio_end_sector(bio), maxsector); +} + +#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); + +static bool should_fail_request(struct hd_struct *part, unsigned int bytes) +{ + return part->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); + +#else /* CONFIG_FAIL_MAKE_REQUEST */ + +static inline bool should_fail_request(struct hd_struct *part, + unsigned int bytes) +{ + return false; +} + +#endif /* CONFIG_FAIL_MAKE_REQUEST */ + +static inline bool bio_check_ro(struct bio *bio, struct hd_struct *part) +{ + const int op = bio_op(bio); + + if (part->policy && op_is_write(op)) { + char b[BDEVNAME_SIZE]; + + if (op_is_flush(bio->bi_opf) && !bio_sectors(bio)) + return false; + pr_warn("Trying to write to read-only block-device %s (partno %d)\n", + bio_devname(bio, b), part->partno); + /* Older lvm-tools actually trigger this */ + return false; + } + + return false; +} + +static noinline int should_fail_bio(struct bio *bio) +{ + if (should_fail_request(&bio->bi_disk->part0, 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) +{ + unsigned int nr_sectors = bio_sectors(bio); + + if (nr_sectors && maxsector && + (nr_sectors > maxsector || + bio->bi_iter.bi_sector > maxsector - nr_sectors)) { + handle_bad_sector(bio, maxsector); + return -EIO; + } + return 0; +} + +/* + * Remap block n of partition p to block n+start(p) of the disk. + */ +static inline int blk_partition_remap(struct bio *bio) +{ + struct hd_struct *p; + int ret = -EIO; + + rcu_read_lock(); + p = __disk_get_part(bio->bi_disk, bio->bi_partno); + if (unlikely(!p)) + goto out; + if (unlikely(should_fail_request(p, bio->bi_iter.bi_size))) + goto out; + if (unlikely(bio_check_ro(bio, p))) + goto out; + + if (bio_sectors(bio)) { + if (bio_check_eod(bio, part_nr_sects_read(p))) + goto out; + bio->bi_iter.bi_sector += p->start_sect; + trace_block_bio_remap(bio->bi_disk->queue, bio, part_devt(p), + bio->bi_iter.bi_sector - p->start_sect); + } + bio->bi_partno = 0; + ret = 0; +out: + rcu_read_unlock(); + return ret; +} + +/* + * Check write append to a zoned block device. + */ +static inline blk_status_t blk_check_zone_append(struct request_queue *q, + struct bio *bio) +{ + sector_t pos = bio->bi_iter.bi_sector; + int nr_sectors = bio_sectors(bio); + + /* Only applicable to zoned block devices */ + if (!blk_queue_is_zoned(q)) + return BLK_STS_NOTSUPP; + + /* The bio sector must point to the start of a sequential zone */ + if (pos & (blk_queue_zone_sectors(q) - 1) || + !blk_queue_zone_is_seq(q, pos)) + 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 noinline_for_stack bool submit_bio_checks(struct bio *bio) +{ + struct request_queue *q = bio->bi_disk->queue; + blk_status_t status = BLK_STS_IOERR; + struct blk_plug *plug; + + might_sleep(); + + plug = blk_mq_plug(q, 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) && !blk_queue_nowait(q)) + goto not_supported; + + if (should_fail_bio(bio)) + goto end_io; + + if (bio->bi_partno) { + if (unlikely(blk_partition_remap(bio))) + goto end_io; + } else { + if (unlikely(bio_check_ro(bio, &bio->bi_disk->part0))) + goto end_io; + if (unlikely(bio_check_eod(bio, get_capacity(bio->bi_disk)))) + 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->bi_opf &= ~REQ_HIPRI; + + switch (bio_op(bio)) { + case REQ_OP_DISCARD: + if (!blk_queue_discard(q)) + goto not_supported; + break; + case REQ_OP_SECURE_ERASE: + if (!blk_queue_secure_erase(q)) + goto not_supported; + break; + case REQ_OP_WRITE_SAME: + if (!q->limits.max_write_same_sectors) + 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 (!blk_queue_is_zoned(q)) + goto not_supported; + break; + case REQ_OP_ZONE_RESET_ALL: + if (!blk_queue_is_zoned(q) || !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; + } + + /* + * Various block parts want %current->io_context, so allocate it up + * front rather than dealing with lots of pain to allocate it only + * where needed. This may fail and the block layer knows how to live + * with it. + */ + if (unlikely(!current->io_context)) + create_task_io_context(current, GFP_ATOMIC, q->node); + + if (blk_throtl_bio(bio)) + return false; + + blk_cgroup_bio_start(bio); + blkcg_bio_issue_init(bio); + + if (!bio_flagged(bio, BIO_TRACE_COMPLETION)) { + trace_block_bio_queue(q, bio); + /* Now that enqueuing has been traced, we need to trace + * completion as well. + */ + bio_set_flag(bio, BIO_TRACE_COMPLETION); + } + return true; + +not_supported: + status = BLK_STS_NOTSUPP; +end_io: + bio->bi_status = status; + bio_endio(bio); + return false; +} + +static blk_qc_t __submit_bio(struct bio *bio) +{ + struct gendisk *disk = bio->bi_disk; + blk_qc_t ret = BLK_QC_T_NONE; + + if (blk_crypto_bio_prep(&bio)) { + if (!disk->fops->submit_bio) + return blk_mq_submit_bio(bio); + ret = disk->fops->submit_bio(bio); + } + blk_queue_exit(disk->queue); + return ret; +} + +/* + * 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_bio, but that haven't been processed yet. + */ +static blk_qc_t __submit_bio_noacct(struct bio *bio) +{ + struct bio_list bio_list_on_stack[2]; + blk_qc_t ret = BLK_QC_T_NONE; + + 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 = bio->bi_disk->queue; + struct bio_list lower, same; + + if (unlikely(bio_queue_enter(bio) != 0)) + continue; + + /* + * 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]); + + ret = __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 == bio->bi_disk->queue) + 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; + return ret; +} + +static blk_qc_t __submit_bio_noacct_mq(struct bio *bio) +{ + struct bio_list bio_list[2] = { }; + blk_qc_t ret = BLK_QC_T_NONE; + + current->bio_list = bio_list; + + do { + struct gendisk *disk = bio->bi_disk; + + if (unlikely(bio_queue_enter(bio) != 0)) + continue; + + if (!blk_crypto_bio_prep(&bio)) { + blk_queue_exit(disk->queue); + ret = BLK_QC_T_NONE; + continue; + } + + ret = blk_mq_submit_bio(bio); + } while ((bio = bio_list_pop(&bio_list[0]))); + + current->bio_list = NULL; + return ret; +} + +/** + * 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. + */ +blk_qc_t submit_bio_noacct(struct bio *bio) +{ + if (!submit_bio_checks(bio)) + return BLK_QC_T_NONE; + + /* + * 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); + return BLK_QC_T_NONE; + } + + if (!bio->bi_disk->fops->submit_bio) + return __submit_bio_noacct_mq(bio); + return __submit_bio_noacct(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_disk and bi_partno fields. + * + * 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 thecaller until ->bi_end_io() has + * been called. + */ +blk_qc_t submit_bio(struct bio *bio) +{ + if (blkcg_punt_bio_submit(bio)) + return BLK_QC_T_NONE; + + /* + * If it's a regular read/write or a barrier with data attached, + * go through the normal accounting stuff before submission. + */ + if (bio_has_data(bio)) { + unsigned int count; + + if (unlikely(bio_op(bio) == REQ_OP_WRITE_SAME)) + count = queue_logical_block_size(bio->bi_disk->queue) >> 9; + else + count = bio_sectors(bio); + + if (op_is_write(bio_op(bio))) { + count_vm_events(PGPGOUT, count); + } else { + task_io_account_read(bio->bi_iter.bi_size); + count_vm_events(PGPGIN, count); + } + + if (unlikely(block_dump)) { + char b[BDEVNAME_SIZE]; + printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n", + current->comm, task_pid_nr(current), + op_is_write(bio_op(bio)) ? "WRITE" : "READ", + (unsigned long long)bio->bi_iter.bi_sector, + bio_devname(bio, b), count); + } + } + + /* + * If we're reading data that is part of the userspace workingset, count + * submission time as memory stall. When the device is congested, or + * the submitting cgroup IO-throttled, submission can be a significant + * part of overall IO time. + */ + if (unlikely(bio_op(bio) == REQ_OP_READ && + bio_flagged(bio, BIO_WORKINGSET))) { + unsigned long pflags; + blk_qc_t ret; + + psi_memstall_enter(&pflags); + ret = submit_bio_noacct(bio); + psi_memstall_leave(&pflags); + + return ret; + } + + return submit_bio_noacct(bio); +} +EXPORT_SYMBOL(submit_bio); + +/** + * blk_cloned_rq_check_limits - Helper function to check a cloned request + * for the new queue limits + * @q: the queue + * @rq: the request being checked + * + * Description: + * @rq may have been made based on weaker limitations of upper-level queues + * in request stacking drivers, and it may violate the limitation of @q. + * Since the block layer and the underlying device driver trust @rq + * after it is inserted to @q, it should be checked against @q before + * the insertion using this generic function. + * + * Request stacking drivers like request-based dm may change the queue + * limits when retrying requests on other queues. Those requests need + * to be checked against the new queue limits again during dispatch. + */ +static blk_status_t blk_cloned_rq_check_limits(struct request_queue *q, + struct request *rq) +{ + unsigned int max_sectors = blk_queue_get_max_sectors(q, req_op(rq)); + + if (blk_rq_sectors(rq) > max_sectors) { + /* + * SCSI device does not have a good way to return if + * Write Same/Zero is actually supported. If a device rejects + * a non-read/write command (discard, write same,etc.) the + * low-level device driver will set the relevant queue limit to + * 0 to prevent blk-lib from issuing more of the offending + * operations. Commands queued prior to the queue limit being + * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O + * errors being propagated to upper layers. + */ + if (max_sectors == 0) + return BLK_STS_NOTSUPP; + + printk(KERN_ERR "%s: over max size limit. (%u > %u)\n", + __func__, blk_rq_sectors(rq), max_sectors); + return BLK_STS_IOERR; + } + + /* + * queue's settings related to segment counting like q->bounce_pfn + * may differ from that of other stacking queues. + * Recalculate it to check the request correctly on this queue's + * limitation. + */ + rq->nr_phys_segments = blk_recalc_rq_segments(rq); + if (rq->nr_phys_segments > queue_max_segments(q)) { + printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n", + __func__, rq->nr_phys_segments, queue_max_segments(q)); + return BLK_STS_IOERR; + } + + return BLK_STS_OK; +} + +/** + * blk_insert_cloned_request - Helper for stacking drivers to submit a request + * @q: the queue to submit the request + * @rq: the request being queued + */ +blk_status_t blk_insert_cloned_request(struct request_queue *q, struct request *rq) +{ + blk_status_t ret; + + ret = blk_cloned_rq_check_limits(q, rq); + if (ret != BLK_STS_OK) + return ret; + + if (rq->rq_disk && + should_fail_request(&rq->rq_disk->part0, blk_rq_bytes(rq))) + return BLK_STS_IOERR; + + if (blk_crypto_insert_cloned_request(rq)) + return BLK_STS_IOERR; + + if (blk_queue_io_stat(q)) + blk_account_io_start(rq); + + /* + * Since we have a scheduler attached on the top device, + * bypass a potential scheduler on the bottom device for + * insert. + */ + return blk_mq_request_issue_directly(rq, true); +} +EXPORT_SYMBOL_GPL(blk_insert_cloned_request); + +/** + * blk_rq_err_bytes - determine number of bytes till the next failure boundary + * @rq: request to examine + * + * Description: + * A request could be merge of IOs which require different failure + * handling. This function determines the number of bytes which + * can be failed from the beginning of the request without + * crossing into area which need to be retried further. + * + * Return: + * The number of bytes to fail. + */ +unsigned int blk_rq_err_bytes(const struct request *rq) +{ + unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK; + unsigned int bytes = 0; + struct bio *bio; + + if (!(rq->rq_flags & RQF_MIXED_MERGE)) + return blk_rq_bytes(rq); + + /* + * Currently the only 'mixing' which can happen is between + * different fastfail types. We can safely fail portions + * which have all the failfast bits that the first one has - + * the ones which are at least as eager to fail as the first + * one. + */ + for (bio = rq->bio; bio; bio = bio->bi_next) { + if ((bio->bi_opf & ff) != ff) + break; + bytes += bio->bi_iter.bi_size; + } + + /* this could lead to infinite loop */ + BUG_ON(blk_rq_bytes(rq) && !bytes); + return bytes; +} +EXPORT_SYMBOL_GPL(blk_rq_err_bytes); + +static void update_io_ticks(struct hd_struct *part, unsigned long now, bool end) +{ + unsigned long stamp; +again: + stamp = READ_ONCE(part->stamp); + if (unlikely(stamp != now)) { + if (likely(cmpxchg(&part->stamp, stamp, now) == stamp)) + __part_stat_add(part, io_ticks, end ? now - stamp : 1); + } + if (part->partno) { + part = &part_to_disk(part)->part0; + goto again; + } +} + +static void blk_account_io_completion(struct request *req, unsigned int bytes) +{ + if (req->part && blk_do_io_stat(req)) { + const int sgrp = op_stat_group(req_op(req)); + struct hd_struct *part; + + part_stat_lock(); + part = req->part; + part_stat_add(part, sectors[sgrp], bytes >> 9); + part_stat_unlock(); + } +} + +void blk_account_io_done(struct request *req, u64 now) +{ + /* + * Account IO completion. flush_rq isn't accounted as a + * normal IO on queueing nor completion. Accounting the + * containing request is enough. + */ + if (req->part && blk_do_io_stat(req) && + !(req->rq_flags & RQF_FLUSH_SEQ)) { + const int sgrp = op_stat_group(req_op(req)); + struct hd_struct *part; + + part_stat_lock(); + part = req->part; + + update_io_ticks(part, jiffies, true); + part_stat_inc(part, ios[sgrp]); + part_stat_add(part, nsecs[sgrp], now - req->start_time_ns); + part_stat_unlock(); + + hd_struct_put(part); + } +} + +void blk_account_io_start(struct request *rq) +{ + if (!blk_do_io_stat(rq)) + return; + + rq->part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); + + part_stat_lock(); + update_io_ticks(rq->part, jiffies, false); + part_stat_unlock(); +} + +static unsigned long __part_start_io_acct(struct hd_struct *part, + unsigned int sectors, unsigned int op) +{ + const int sgrp = op_stat_group(op); + unsigned long now = READ_ONCE(jiffies); + + part_stat_lock(); + update_io_ticks(part, now, false); + part_stat_inc(part, ios[sgrp]); + part_stat_add(part, sectors[sgrp], sectors); + part_stat_local_inc(part, in_flight[op_is_write(op)]); + part_stat_unlock(); + + return now; +} + +unsigned long part_start_io_acct(struct gendisk *disk, struct hd_struct **part, + struct bio *bio) +{ + *part = disk_map_sector_rcu(disk, bio->bi_iter.bi_sector); + + return __part_start_io_acct(*part, bio_sectors(bio), bio_op(bio)); +} +EXPORT_SYMBOL_GPL(part_start_io_acct); + +unsigned long disk_start_io_acct(struct gendisk *disk, unsigned int sectors, + unsigned int op) +{ + return __part_start_io_acct(&disk->part0, sectors, op); +} +EXPORT_SYMBOL(disk_start_io_acct); + +static void __part_end_io_acct(struct hd_struct *part, unsigned int 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(part, now, true); + part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration)); + part_stat_local_dec(part, in_flight[op_is_write(op)]); + part_stat_unlock(); +} + +void part_end_io_acct(struct hd_struct *part, struct bio *bio, + unsigned long start_time) +{ + __part_end_io_acct(part, bio_op(bio), start_time); + hd_struct_put(part); +} +EXPORT_SYMBOL_GPL(part_end_io_acct); + +void disk_end_io_acct(struct gendisk *disk, unsigned int op, + unsigned long start_time) +{ + __part_end_io_acct(&disk->part0, op, start_time); +} +EXPORT_SYMBOL(disk_end_io_acct); + +/* + * Steal bios from a request and add them to a bio list. + * The request must not have been partially completed before. + */ +void blk_steal_bios(struct bio_list *list, struct request *rq) +{ + if (rq->bio) { + if (list->tail) + list->tail->bi_next = rq->bio; + else + list->head = rq->bio; + list->tail = rq->biotail; + + rq->bio = NULL; + rq->biotail = NULL; + } + + rq->__data_len = 0; +} +EXPORT_SYMBOL_GPL(blk_steal_bios); + +/** + * blk_update_request - Special helper function for request stacking drivers + * @req: the request being processed + * @error: block status code + * @nr_bytes: number of bytes to complete @req + * + * Description: + * Ends I/O on a number of bytes attached to @req, but doesn't complete + * the request structure even if @req doesn't have leftover. + * If @req has leftover, sets it up for the next range of segments. + * + * This special helper function is only for request stacking drivers + * (e.g. request-based dm) so that they can handle partial completion. + * Actual device drivers should use blk_mq_end_request instead. + * + * Passing the result of blk_rq_bytes() as @nr_bytes guarantees + * %false return from this function. + * + * Note: + * The RQF_SPECIAL_PAYLOAD flag is ignored on purpose in both + * blk_rq_bytes() and in blk_update_request(). + * + * Return: + * %false - this request doesn't have any more data + * %true - this request has more data + **/ +bool blk_update_request(struct request *req, blk_status_t error, + unsigned int nr_bytes) +{ + int total_bytes; + + trace_block_rq_complete(req, blk_status_to_errno(error), nr_bytes); + + if (!req->bio) + return false; + +#ifdef CONFIG_BLK_DEV_INTEGRITY + if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ && + error == BLK_STS_OK) + req->q->integrity.profile->complete_fn(req, nr_bytes); +#endif + + /* + * Upper layers may call blk_crypto_evict_key() anytime after the last + * bio_endio(). Therefore, the keyslot must be released before that. + */ + if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req)) + __blk_crypto_rq_put_keyslot(req); + + if (unlikely(error && !blk_rq_is_passthrough(req) && + !(req->rq_flags & RQF_QUIET))) + print_req_error(req, error, __func__); + + blk_account_io_completion(req, nr_bytes); + + total_bytes = 0; + while (req->bio) { + struct bio *bio = req->bio; + unsigned bio_bytes = min(bio->bi_iter.bi_size, nr_bytes); + + if (bio_bytes == bio->bi_iter.bi_size) + req->bio = bio->bi_next; + + /* Completion has already been traced */ + bio_clear_flag(bio, BIO_TRACE_COMPLETION); + req_bio_endio(req, bio, bio_bytes, error); + + total_bytes += bio_bytes; + nr_bytes -= bio_bytes; + + if (!nr_bytes) + break; + } + + /* + * completely done + */ + if (!req->bio) { + /* + * Reset counters so that the request stacking driver + * can find how many bytes remain in the request + * later. + */ + req->__data_len = 0; + return false; + } + + req->__data_len -= total_bytes; + + /* update sector only for requests with clear definition of sector */ + if (!blk_rq_is_passthrough(req)) + req->__sector += total_bytes >> 9; + + /* mixed attributes always follow the first bio */ + if (req->rq_flags & RQF_MIXED_MERGE) { + req->cmd_flags &= ~REQ_FAILFAST_MASK; + req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; + } + + if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { + /* + * If total number of sectors is less than the first segment + * size, something has gone terribly wrong. + */ + if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { + blk_dump_rq_flags(req, "request botched"); + req->__data_len = blk_rq_cur_bytes(req); + } + + /* recalculate the number of segments */ + req->nr_phys_segments = blk_recalc_rq_segments(req); + } + + return true; +} +EXPORT_SYMBOL_GPL(blk_update_request); + +#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE +/** + * rq_flush_dcache_pages - Helper function to flush all pages in a request + * @rq: the request to be flushed + * + * Description: + * Flush all pages in @rq. + */ +void rq_flush_dcache_pages(struct request *rq) +{ + struct req_iterator iter; + struct bio_vec bvec; + + rq_for_each_segment(bvec, rq, iter) + flush_dcache_page(bvec.bv_page); +} +EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); +#endif + +/** + * 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); + +/** + * blk_rq_unprep_clone - Helper function to free all bios in a cloned request + * @rq: the clone request to be cleaned up + * + * Description: + * Free all bios in @rq for a cloned request. + */ +void blk_rq_unprep_clone(struct request *rq) +{ + struct bio *bio; + + while ((bio = rq->bio) != NULL) { + rq->bio = bio->bi_next; + + bio_put(bio); + } +} +EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); + +/** + * blk_rq_prep_clone - Helper function to setup clone request + * @rq: the request to be setup + * @rq_src: original request to be cloned + * @bs: bio_set that bios for clone are allocated from + * @gfp_mask: memory allocation mask for bio + * @bio_ctr: setup function to be called for each clone bio. + * Returns %0 for success, non %0 for failure. + * @data: private data to be passed to @bio_ctr + * + * Description: + * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. + * Also, pages which the original bios are pointing to are not copied + * and the cloned bios just point same pages. + * So cloned bios must be completed before original bios, which means + * the caller must complete @rq before @rq_src. + */ +int blk_rq_prep_clone(struct request *rq, struct request *rq_src, + struct bio_set *bs, gfp_t gfp_mask, + int (*bio_ctr)(struct bio *, struct bio *, void *), + void *data) +{ + struct bio *bio, *bio_src; + + if (!bs) + bs = &fs_bio_set; + + __rq_for_each_bio(bio_src, rq_src) { + bio = bio_clone_fast(bio_src, gfp_mask, bs); + if (!bio) + goto free_and_out; + + if (bio_ctr && bio_ctr(bio, bio_src, data)) + goto free_and_out; + + if (rq->bio) { + rq->biotail->bi_next = bio; + rq->biotail = bio; + } else { + rq->bio = rq->biotail = bio; + } + bio = NULL; + } + + /* Copy attributes of the original request to the clone request. */ + rq->__sector = blk_rq_pos(rq_src); + rq->__data_len = blk_rq_bytes(rq_src); + if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) { + rq->rq_flags |= RQF_SPECIAL_PAYLOAD; + rq->special_vec = rq_src->special_vec; + } + rq->nr_phys_segments = rq_src->nr_phys_segments; + rq->ioprio = rq_src->ioprio; + + if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0) + goto free_and_out; + + return 0; + +free_and_out: + if (bio) + bio_put(bio); + blk_rq_unprep_clone(rq); + + return -ENOMEM; +} +EXPORT_SYMBOL_GPL(blk_rq_prep_clone); + +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); + +/** + * 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) +{ + struct task_struct *tsk = current; + + /* + * If this is a nested plug, don't actually assign it. + */ + if (tsk->plug) + return; + + INIT_LIST_HEAD(&plug->mq_list); + INIT_LIST_HEAD(&plug->cb_list); + plug->rq_count = 0; + plug->multiple_queues = false; + plug->nowait = false; + + /* + * Store ordering should not be needed here, since a potential + * preempt will imply a full memory barrier + */ + tsk->plug = plug; +} +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_list(struct blk_plug *plug, bool from_schedule) +{ + flush_plug_callbacks(plug, from_schedule); + + if (!list_empty(&plug->mq_list)) + blk_mq_flush_plug_list(plug, from_schedule); +} + +/** + * 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) + return; + blk_flush_plug_list(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(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; +} |