| // 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/highmem.h> |
| #include <linux/mm.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/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" |
| |
| #ifdef CONFIG_DEBUG_FS |
| struct dentry *blk_debugfs_root; |
| #endif |
| |
| 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 = -1; |
| rq->internal_tag = -1; |
| rq->start_time_ns = ktime_get_ns(); |
| rq->part = NULL; |
| refcount_set(&rq->ref, 1); |
| 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(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" }, |
| |
| /* 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); |
| |
| /* 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 ->make_request_fn 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); |
| |
| 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. |
| */ |
| void blk_cleanup_queue(struct request_queue *q) |
| { |
| /* mark @q DYING, no new request or merges will be allowed afterwards */ |
| mutex_lock(&q->sysfs_lock); |
| blk_set_queue_dying(q); |
| |
| blk_queue_flag_set(QUEUE_FLAG_NOMERGES, q); |
| blk_queue_flag_set(QUEUE_FLAG_NOXMERGES, q); |
| blk_queue_flag_set(QUEUE_FLAG_DYING, q); |
| mutex_unlock(&q->sysfs_lock); |
| |
| /* |
| * 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); |
| |
| percpu_ref_exit(&q->q_usage_counter); |
| |
| /* @q is and will stay empty, shutdown and put */ |
| blk_put_queue(q); |
| } |
| EXPORT_SYMBOL(blk_cleanup_queue); |
| |
| struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
| { |
| return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE); |
| } |
| EXPORT_SYMBOL(blk_alloc_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_PREEMPT |
| */ |
| int blk_queue_enter(struct request_queue *q, blk_mq_req_flags_t flags) |
| { |
| const bool pm = flags & BLK_MQ_REQ_PREEMPT; |
| |
| 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 || !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 && |
| (pm || (blk_pm_request_resume(q), |
| !blk_queue_pm_only(q)))) || |
| blk_queue_dying(q)); |
| if (blk_queue_dying(q)) |
| 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) |
| { |
| } |
| |
| /** |
| * blk_alloc_queue_node - allocate a request queue |
| * @gfp_mask: memory allocation flags |
| * @node_id: NUMA node to allocate memory from |
| */ |
| struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id) |
| { |
| struct request_queue *q; |
| int ret; |
| |
| q = kmem_cache_alloc_node(blk_requestq_cachep, |
| gfp_mask | __GFP_ZERO, node_id); |
| if (!q) |
| return NULL; |
| |
| q->last_merge = NULL; |
| |
| q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask); |
| 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(gfp_mask, node_id); |
| if (!q->backing_dev_info) |
| goto fail_split; |
| |
| q->stats = blk_alloc_queue_stats(); |
| if (!q->stats) |
| goto fail_stats; |
| |
| q->backing_dev_info->ra_pages = VM_READAHEAD_PAGES; |
| q->backing_dev_info->io_pages = VM_READAHEAD_PAGES; |
| q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK; |
| q->backing_dev_info->name = "block"; |
| q->node = node_id; |
| |
| 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); |
| |
| #ifdef CONFIG_BLK_DEV_IO_TRACE |
| mutex_init(&q->blk_trace_mutex); |
| #endif |
| 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; |
| |
| 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_node); |
| |
| 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_PREEMPT)); |
| |
| 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); |
| |
| bool bio_attempt_back_merge(struct request *req, struct bio *bio, |
| unsigned int nr_segs) |
| { |
| const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
| |
| if (!ll_back_merge_fn(req, bio, nr_segs)) |
| return false; |
| |
| trace_block_bio_backmerge(req->q, req, bio); |
| rq_qos_merge(req->q, req, bio); |
| |
| if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) |
| blk_rq_set_mixed_merge(req); |
| |
| req->biotail->bi_next = bio; |
| req->biotail = bio; |
| req->__data_len += bio->bi_iter.bi_size; |
| |
| bio_crypt_free_ctx(bio); |
| |
| blk_account_io_start(req, false); |
| return true; |
| } |
| |
| bool bio_attempt_front_merge(struct request *req, struct bio *bio, |
| unsigned int nr_segs) |
| { |
| const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
| |
| if (!ll_front_merge_fn(req, bio, nr_segs)) |
| return false; |
| |
| trace_block_bio_frontmerge(req->q, req, bio); |
| rq_qos_merge(req->q, req, bio); |
| |
| if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) |
| blk_rq_set_mixed_merge(req); |
| |
| bio->bi_next = req->bio; |
| req->bio = bio; |
| |
| req->__sector = bio->bi_iter.bi_sector; |
| req->__data_len += bio->bi_iter.bi_size; |
| |
| bio_crypt_do_front_merge(req, bio); |
| |
| blk_account_io_start(req, false); |
| return true; |
| } |
| |
| bool bio_attempt_discard_merge(struct request_queue *q, struct request *req, |
| struct bio *bio) |
| { |
| unsigned short segments = blk_rq_nr_discard_segments(req); |
| |
| if (segments >= queue_max_discard_segments(q)) |
| goto no_merge; |
| if (blk_rq_sectors(req) + bio_sectors(bio) > |
| blk_rq_get_max_sectors(req, blk_rq_pos(req))) |
| goto no_merge; |
| |
| rq_qos_merge(q, req, bio); |
| |
| req->biotail->bi_next = bio; |
| req->biotail = bio; |
| req->__data_len += bio->bi_iter.bi_size; |
| req->nr_phys_segments = segments + 1; |
| |
| blk_account_io_start(req, false); |
| return true; |
| no_merge: |
| req_set_nomerge(q, req); |
| return false; |
| } |
| |
| /** |
| * blk_attempt_plug_merge - try to merge with %current's plugged list |
| * @q: request_queue new bio is being queued at |
| * @bio: new bio being queued |
| * @nr_segs: number of segments in @bio |
| * @same_queue_rq: pointer to &struct request that gets filled in when |
| * another request associated with @q is found on the plug list |
| * (optional, may be %NULL) |
| * |
| * Determine whether @bio being queued on @q can be merged with a request |
| * on %current's plugged list. Returns %true if merge was successful, |
| * otherwise %false. |
| * |
| * Plugging coalesces IOs from the same issuer for the same purpose without |
| * going through @q->queue_lock. As such it's more of an issuing mechanism |
| * than scheduling, and the request, while may have elvpriv data, is not |
| * added on the elevator at this point. In addition, we don't have |
| * reliable access to the elevator outside queue lock. Only check basic |
| * merging parameters without querying the elevator. |
| * |
| * Caller must ensure !blk_queue_nomerges(q) beforehand. |
| */ |
| bool blk_attempt_plug_merge(struct request_queue *q, struct bio *bio, |
| unsigned int nr_segs, struct request **same_queue_rq) |
| { |
| struct blk_plug *plug; |
| struct request *rq; |
| struct list_head *plug_list; |
| |
| plug = blk_mq_plug(q, bio); |
| if (!plug) |
| return false; |
| |
| plug_list = &plug->mq_list; |
| |
| list_for_each_entry_reverse(rq, plug_list, queuelist) { |
| bool merged = false; |
| |
| if (rq->q == q && same_queue_rq) { |
| /* |
| * Only blk-mq multiple hardware queues case checks the |
| * rq in the same queue, there should be only one such |
| * rq in a queue |
| **/ |
| *same_queue_rq = rq; |
| } |
| |
| if (rq->q != q || !blk_rq_merge_ok(rq, bio)) |
| continue; |
| |
| switch (blk_try_merge(rq, bio)) { |
| case ELEVATOR_BACK_MERGE: |
| merged = bio_attempt_back_merge(rq, bio, nr_segs); |
| break; |
| case ELEVATOR_FRONT_MERGE: |
| merged = bio_attempt_front_merge(rq, bio, nr_segs); |
| break; |
| case ELEVATOR_DISCARD_MERGE: |
| merged = bio_attempt_discard_merge(q, rq, bio); |
| break; |
| default: |
| break; |
| } |
| |
| if (merged) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| 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; |
| |
| WARN_ONCE(1, |
| "generic_make_request: 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; |
| } |
| |
| static noinline_for_stack bool |
| generic_make_request_checks(struct bio *bio) |
| { |
| struct request_queue *q; |
| int nr_sectors = bio_sectors(bio); |
| blk_status_t status = BLK_STS_IOERR; |
| char b[BDEVNAME_SIZE]; |
| |
| might_sleep(); |
| |
| q = bio->bi_disk->queue; |
| if (unlikely(!q)) { |
| printk(KERN_ERR |
| "generic_make_request: Trying to access " |
| "nonexistent block-device %s (%Lu)\n", |
| bio_devname(bio, b), (long long)bio->bi_iter.bi_sector); |
| goto end_io; |
| } |
| |
| /* |
| * Non-mq queues do not honor REQ_NOWAIT, so complete a bio |
| * with BLK_STS_AGAIN status in order to catch -EAGAIN and |
| * to give a chance to the caller to repeat request gracefully. |
| */ |
| if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_mq(q)) { |
| status = BLK_STS_AGAIN; |
| goto end_io; |
| } |
| |
| 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 make_request 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 (!nr_sectors) { |
| 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_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 and lazy ioc |
| * allocation ends up trading a lot of pain for a small amount of |
| * memory. Just allocate it upfront. This may fail and block |
| * layer knows how to live with it. |
| */ |
| create_io_context(GFP_ATOMIC, q->node); |
| |
| if (!blkcg_bio_issue_check(q, bio)) |
| return false; |
| |
| 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; |
| } |
| |
| /** |
| * generic_make_request - hand a buffer to its device driver for I/O |
| * @bio: The bio describing the location in memory and on the device. |
| * |
| * generic_make_request() is used to make I/O requests of block |
| * devices. It is passed a &struct bio, which describes the I/O that needs |
| * to be done. |
| * |
| * generic_make_request() does not return any status. The |
| * success/failure status of the request, along with notification of |
| * completion, is delivered asynchronously through the bio->bi_end_io |
| * function described (one day) else where. |
| * |
| * The caller of generic_make_request must make sure that bi_io_vec |
| * are set to describe the memory buffer, and that bi_dev and bi_sector are |
| * set to describe the device address, and the |
| * bi_end_io and optionally bi_private are set to describe how |
| * completion notification should be signaled. |
| * |
| * generic_make_request and the drivers it calls may use bi_next if this |
| * bio happens to be merged with someone else, and may resubmit the bio to |
| * a lower device by calling into generic_make_request recursively, which |
| * means the bio should NOT be touched after the call to ->make_request_fn. |
| */ |
| blk_qc_t generic_make_request(struct bio *bio) |
| { |
| /* |
| * bio_list_on_stack[0] contains bios submitted by the current |
| * make_request_fn. |
| * bio_list_on_stack[1] contains bios that were submitted before |
| * the current make_request_fn, but that haven't been processed |
| * yet. |
| */ |
| struct bio_list bio_list_on_stack[2]; |
| blk_qc_t ret = BLK_QC_T_NONE; |
| |
| if (!generic_make_request_checks(bio)) |
| goto out; |
| |
| /* |
| * We only want one ->make_request_fn to be active at a time, else |
| * stack usage with stacked devices could be a problem. So use |
| * current->bio_list to keep a list of requests submited by a |
| * make_request_fn function. current->bio_list is also used as a |
| * flag to say if generic_make_request is currently active in this |
| * task or not. If it is NULL, then no make_request is active. If |
| * it is non-NULL, then a make_request is active, and new requests |
| * should be added at the tail |
| */ |
| if (current->bio_list) { |
| bio_list_add(¤t->bio_list[0], bio); |
| goto out; |
| } |
| |
| /* following loop 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. ->make_request() may indeed add some more bios |
| * through a recursive call to generic_make_request. 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 ->make_request() again. |
| */ |
| 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; |
| blk_mq_req_flags_t flags = bio->bi_opf & REQ_NOWAIT ? |
| BLK_MQ_REQ_NOWAIT : 0; |
| |
| if (likely(blk_queue_enter(q, flags) == 0)) { |
| 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]); |
| if (blk_crypto_bio_prep(&bio)) |
| ret = q->make_request_fn(q, bio); |
| |
| blk_queue_exit(q); |
| |
| /* 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]); |
| } else { |
| if (unlikely(!blk_queue_dying(q) && |
| (bio->bi_opf & REQ_NOWAIT))) |
| bio_wouldblock_error(bio); |
| else |
| bio_io_error(bio); |
| } |
| bio = bio_list_pop(&bio_list_on_stack[0]); |
| } while (bio); |
| current->bio_list = NULL; /* deactivate */ |
| |
| out: |
| return ret; |
| } |
| EXPORT_SYMBOL(generic_make_request); |
| |
| /** |
| * direct_make_request - hand a buffer directly to its device driver for I/O |
| * @bio: The bio describing the location in memory and on the device. |
| * |
| * This function behaves like generic_make_request(), but does not protect |
| * against recursion. Must only be used if the called driver is known |
| * to not call generic_make_request (or direct_make_request) again from |
| * its make_request function. (Calling direct_make_request again from |
| * a workqueue is perfectly fine as that doesn't recurse). |
| */ |
| blk_qc_t direct_make_request(struct bio *bio) |
| { |
| struct request_queue *q = bio->bi_disk->queue; |
| bool nowait = bio->bi_opf & REQ_NOWAIT; |
| blk_qc_t ret = BLK_QC_T_NONE; |
| |
| if (!generic_make_request_checks(bio)) |
| return BLK_QC_T_NONE; |
| |
| if (unlikely(blk_queue_enter(q, nowait ? BLK_MQ_REQ_NOWAIT : 0))) { |
| if (nowait && !blk_queue_dying(q)) |
| bio->bi_status = BLK_STS_AGAIN; |
| else |
| bio->bi_status = BLK_STS_IOERR; |
| bio_endio(bio); |
| return BLK_QC_T_NONE; |
| } |
| |
| if (blk_crypto_bio_prep(&bio)) |
| ret = q->make_request_fn(q, bio); |
| blk_queue_exit(q); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(direct_make_request); |
| |
| /** |
| * 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 very similar in purpose to generic_make_request(), and |
| * uses that function to do most of the work. Both are fairly rough |
| * interfaces; @bio must be presetup and ready for I/O. |
| * |
| */ |
| blk_qc_t submit_bio(struct bio *bio) |
| { |
| bool workingset_read = false; |
| unsigned long pflags; |
| blk_qc_t ret; |
| |
| 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 { |
| if (bio_flagged(bio, BIO_WORKINGSET)) |
| workingset_read = true; |
| 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 (workingset_read) |
| psi_memstall_enter(&pflags); |
| |
| ret = generic_make_request(bio); |
| |
| if (workingset_read) |
| psi_memstall_leave(&pflags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(submit_bio); |
| |
| /** |
| * blk_cloned_rq_check_limits - Helper function to check a cloned request |
| * for new the 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 int blk_cloned_rq_check_limits(struct request_queue *q, |
| struct request *rq) |
| { |
| if (blk_rq_sectors(rq) > blk_queue_get_max_sectors(q, req_op(rq))) { |
| printk(KERN_ERR "%s: over max size limit. (%u > %u)\n", |
| __func__, blk_rq_sectors(rq), |
| blk_queue_get_max_sectors(q, req_op(rq))); |
| return -EIO; |
| } |
| |
| /* |
| * 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 -EIO; |
| } |
| |
| return 0; |
| } |
| |
| /** |
| * 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) |
| { |
| if (blk_cloned_rq_check_limits(q, rq)) |
| return BLK_STS_IOERR; |
| |
| 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, true); |
| |
| /* |
| * 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); |
| |
| void blk_account_io_completion(struct request *req, unsigned int bytes) |
| { |
| if (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 (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_add(part, time_in_queue, nsecs_to_jiffies64(now - req->start_time_ns)); |
| part_dec_in_flight(req->q, part, rq_data_dir(req)); |
| |
| hd_struct_put(part); |
| part_stat_unlock(); |
| } |
| } |
| |
| void blk_account_io_start(struct request *rq, bool new_io) |
| { |
| struct hd_struct *part; |
| int rw = rq_data_dir(rq); |
| |
| if (!blk_do_io_stat(rq)) |
| return; |
| |
| part_stat_lock(); |
| |
| if (!new_io) { |
| part = rq->part; |
| part_stat_inc(part, merges[rw]); |
| } else { |
| part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq)); |
| if (!hd_struct_try_get(part)) { |
| /* |
| * The partition is already being removed, |
| * the request will be accounted on the disk only |
| * |
| * We take a reference on disk->part0 although that |
| * partition will never be deleted, so we can treat |
| * it as any other partition. |
| */ |
| part = &rq->rq_disk->part0; |
| hd_struct_get(part); |
| } |
| part_inc_in_flight(rq->q, part, rw); |
| rq->part = part; |
| } |
| |
| update_io_ticks(part, jiffies, false); |
| |
| part_stat_unlock(); |
| } |
| |
| /* |
| * 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 |
| |
| 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); |
| |
| /* |
| * Copy attributes of the original request to the clone request. |
| * The actual data parts (e.g. ->cmd, ->sense) are not copied. |
| */ |
| static void __blk_rq_prep_clone(struct request *dst, struct request *src) |
| { |
| dst->__sector = blk_rq_pos(src); |
| dst->__data_len = blk_rq_bytes(src); |
| if (src->rq_flags & RQF_SPECIAL_PAYLOAD) { |
| dst->rq_flags |= RQF_SPECIAL_PAYLOAD; |
| dst->special_vec = src->special_vec; |
| } |
| dst->nr_phys_segments = src->nr_phys_segments; |
| dst->ioprio = src->ioprio; |
| dst->extra_len = src->extra_len; |
| } |
| |
| /** |
| * 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. |
| * The actual data parts of @rq_src (e.g. ->cmd, ->sense) |
| * are not copied, and copying such parts is the caller's responsibility. |
| * 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; |
| } |
| |
| __blk_rq_prep_clone(rq, rq_src); |
| |
| 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_schedule_work_on(int cpu, struct work_struct *work) |
| { |
| return queue_work_on(cpu, kblockd_workqueue, work); |
| } |
| EXPORT_SYMBOL(kblockd_schedule_work_on); |
| |
| 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; |
| |
| /* |
| * 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); |
| |
| 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 * |
| FIELD_SIZEOF(struct request, cmd_flags)); |
| BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * |
| FIELD_SIZEOF(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); |
| |
| #ifdef CONFIG_DEBUG_FS |
| blk_debugfs_root = debugfs_create_dir("block", NULL); |
| #endif |
| |
| return 0; |
| } |