| /* |
| * 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/debugfs.h> |
| #include <linux/bpf.h> |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/block.h> |
| |
| #include "blk.h" |
| #include "blk-mq.h" |
| #include "blk-mq-sched.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 the allocated request tables |
| */ |
| struct kmem_cache *request_cachep; |
| |
| /* |
| * 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) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| queue_flag_set(flag, q); |
| spin_unlock_irqrestore(q->queue_lock, 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) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| queue_flag_clear(flag, q); |
| spin_unlock_irqrestore(q->queue_lock, 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) |
| { |
| unsigned long flags; |
| bool res; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| res = queue_flag_test_and_set(flag, q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| return res; |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_set); |
| |
| /** |
| * blk_queue_flag_test_and_clear - atomically test and clear a queue flag |
| * @flag: flag to be cleared |
| * @q: request queue |
| * |
| * Returns the previous value of @flag - 0 if the flag was not set and 1 if |
| * the flag was set. |
| */ |
| bool blk_queue_flag_test_and_clear(unsigned int flag, struct request_queue *q) |
| { |
| unsigned long flags; |
| bool res; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| res = queue_flag_test_and_clear(flag, q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| return res; |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_flag_test_and_clear); |
| |
| static void blk_clear_congested(struct request_list *rl, int sync) |
| { |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| clear_wb_congested(rl->blkg->wb_congested, sync); |
| #else |
| /* |
| * If !CGROUP_WRITEBACK, all blkg's map to bdi->wb and we shouldn't |
| * flip its congestion state for events on other blkcgs. |
| */ |
| if (rl == &rl->q->root_rl) |
| clear_wb_congested(rl->q->backing_dev_info->wb.congested, sync); |
| #endif |
| } |
| |
| static void blk_set_congested(struct request_list *rl, int sync) |
| { |
| #ifdef CONFIG_CGROUP_WRITEBACK |
| set_wb_congested(rl->blkg->wb_congested, sync); |
| #else |
| /* see blk_clear_congested() */ |
| if (rl == &rl->q->root_rl) |
| set_wb_congested(rl->q->backing_dev_info->wb.congested, sync); |
| #endif |
| } |
| |
| void blk_queue_congestion_threshold(struct request_queue *q) |
| { |
| int nr; |
| |
| nr = q->nr_requests - (q->nr_requests / 8) + 1; |
| if (nr > q->nr_requests) |
| nr = q->nr_requests; |
| q->nr_congestion_on = nr; |
| |
| nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1; |
| if (nr < 1) |
| nr = 1; |
| q->nr_congestion_off = nr; |
| } |
| |
| void blk_rq_init(struct request_queue *q, struct request *rq) |
| { |
| memset(rq, 0, sizeof(*rq)); |
| |
| INIT_LIST_HEAD(&rq->queuelist); |
| INIT_LIST_HEAD(&rq->timeout_list); |
| rq->cpu = -1; |
| 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); |
| } |
| EXPORT_SYMBOL(blk_rq_init); |
| |
| 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) |
| { |
| 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\n", |
| __func__, blk_errors[idx].name, req->rq_disk ? |
| req->rq_disk->disk_name : "?", |
| (unsigned long long)blk_rq_pos(req)); |
| } |
| |
| 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); |
| |
| static void blk_delay_work(struct work_struct *work) |
| { |
| struct request_queue *q; |
| |
| q = container_of(work, struct request_queue, delay_work.work); |
| spin_lock_irq(q->queue_lock); |
| __blk_run_queue(q); |
| spin_unlock_irq(q->queue_lock); |
| } |
| |
| /** |
| * blk_delay_queue - restart queueing after defined interval |
| * @q: The &struct request_queue in question |
| * @msecs: Delay in msecs |
| * |
| * Description: |
| * Sometimes queueing needs to be postponed for a little while, to allow |
| * resources to come back. This function will make sure that queueing is |
| * restarted around the specified time. |
| */ |
| void blk_delay_queue(struct request_queue *q, unsigned long msecs) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| if (likely(!blk_queue_dead(q))) |
| queue_delayed_work(kblockd_workqueue, &q->delay_work, |
| msecs_to_jiffies(msecs)); |
| } |
| EXPORT_SYMBOL(blk_delay_queue); |
| |
| /** |
| * blk_start_queue_async - asynchronously restart a previously stopped queue |
| * @q: The &struct request_queue in question |
| * |
| * Description: |
| * blk_start_queue_async() will clear the stop flag on the queue, and |
| * ensure that the request_fn for the queue is run from an async |
| * context. |
| **/ |
| void blk_start_queue_async(struct request_queue *q) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
| blk_run_queue_async(q); |
| } |
| EXPORT_SYMBOL(blk_start_queue_async); |
| |
| /** |
| * blk_start_queue - restart a previously stopped queue |
| * @q: The &struct request_queue in question |
| * |
| * Description: |
| * blk_start_queue() will clear the stop flag on the queue, and call |
| * the request_fn for the queue if it was in a stopped state when |
| * entered. Also see blk_stop_queue(). |
| **/ |
| void blk_start_queue(struct request_queue *q) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| queue_flag_clear(QUEUE_FLAG_STOPPED, q); |
| __blk_run_queue(q); |
| } |
| EXPORT_SYMBOL(blk_start_queue); |
| |
| /** |
| * blk_stop_queue - stop a queue |
| * @q: The &struct request_queue in question |
| * |
| * Description: |
| * The Linux block layer assumes that a block driver will consume all |
| * entries on the request queue when the request_fn strategy is called. |
| * Often this will not happen, because of hardware limitations (queue |
| * depth settings). If a device driver gets a 'queue full' response, |
| * or if it simply chooses not to queue more I/O at one point, it can |
| * call this function to prevent the request_fn from being called until |
| * the driver has signalled it's ready to go again. This happens by calling |
| * blk_start_queue() to restart queue operations. |
| **/ |
| void blk_stop_queue(struct request_queue *q) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| cancel_delayed_work(&q->delay_work); |
| queue_flag_set(QUEUE_FLAG_STOPPED, q); |
| } |
| EXPORT_SYMBOL(blk_stop_queue); |
| |
| /** |
| * 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); |
| |
| if (q->mq_ops) { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| cancel_delayed_work_sync(&hctx->run_work); |
| } else { |
| cancel_delayed_work_sync(&q->delay_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_run_queue_uncond - run a queue whether or not it has been stopped |
| * @q: The queue to run |
| * |
| * Description: |
| * Invoke request handling on a queue if there are any pending requests. |
| * May be used to restart request handling after a request has completed. |
| * This variant runs the queue whether or not the queue has been |
| * stopped. Must be called with the queue lock held and interrupts |
| * disabled. See also @blk_run_queue. |
| */ |
| inline void __blk_run_queue_uncond(struct request_queue *q) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| if (unlikely(blk_queue_dead(q))) |
| return; |
| |
| /* |
| * Some request_fn implementations, e.g. scsi_request_fn(), unlock |
| * the queue lock internally. As a result multiple threads may be |
| * running such a request function concurrently. Keep track of the |
| * number of active request_fn invocations such that blk_drain_queue() |
| * can wait until all these request_fn calls have finished. |
| */ |
| q->request_fn_active++; |
| q->request_fn(q); |
| q->request_fn_active--; |
| } |
| EXPORT_SYMBOL_GPL(__blk_run_queue_uncond); |
| |
| /** |
| * __blk_run_queue - run a single device queue |
| * @q: The queue to run |
| * |
| * Description: |
| * See @blk_run_queue. |
| */ |
| void __blk_run_queue(struct request_queue *q) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| if (unlikely(blk_queue_stopped(q))) |
| return; |
| |
| __blk_run_queue_uncond(q); |
| } |
| EXPORT_SYMBOL(__blk_run_queue); |
| |
| /** |
| * blk_run_queue_async - run a single device queue in workqueue context |
| * @q: The queue to run |
| * |
| * Description: |
| * Tells kblockd to perform the equivalent of @blk_run_queue on behalf |
| * of us. |
| * |
| * Note: |
| * Since it is not allowed to run q->delay_work after blk_cleanup_queue() |
| * has canceled q->delay_work, callers must hold the queue lock to avoid |
| * race conditions between blk_cleanup_queue() and blk_run_queue_async(). |
| */ |
| void blk_run_queue_async(struct request_queue *q) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) |
| mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); |
| } |
| EXPORT_SYMBOL(blk_run_queue_async); |
| |
| /** |
| * blk_run_queue - run a single device queue |
| * @q: The queue to run |
| * |
| * Description: |
| * Invoke request handling on this queue, if it has pending work to do. |
| * May be used to restart queueing when a request has completed. |
| */ |
| void blk_run_queue(struct request_queue *q) |
| { |
| unsigned long flags; |
| |
| WARN_ON_ONCE(q->mq_ops); |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| __blk_run_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| EXPORT_SYMBOL(blk_run_queue); |
| |
| void blk_put_queue(struct request_queue *q) |
| { |
| kobject_put(&q->kobj); |
| } |
| EXPORT_SYMBOL(blk_put_queue); |
| |
| /** |
| * __blk_drain_queue - drain requests from request_queue |
| * @q: queue to drain |
| * @drain_all: whether to drain all requests or only the ones w/ ELVPRIV |
| * |
| * Drain requests from @q. If @drain_all is set, all requests are drained. |
| * If not, only ELVPRIV requests are drained. The caller is responsible |
| * for ensuring that no new requests which need to be drained are queued. |
| */ |
| static void __blk_drain_queue(struct request_queue *q, bool drain_all) |
| __releases(q->queue_lock) |
| __acquires(q->queue_lock) |
| { |
| int i; |
| |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| while (true) { |
| bool drain = false; |
| |
| /* |
| * The caller might be trying to drain @q before its |
| * elevator is initialized. |
| */ |
| if (q->elevator) |
| elv_drain_elevator(q); |
| |
| blkcg_drain_queue(q); |
| |
| /* |
| * This function might be called on a queue which failed |
| * driver init after queue creation or is not yet fully |
| * active yet. Some drivers (e.g. fd and loop) get unhappy |
| * in such cases. Kick queue iff dispatch queue has |
| * something on it and @q has request_fn set. |
| */ |
| if (!list_empty(&q->queue_head) && q->request_fn) |
| __blk_run_queue(q); |
| |
| drain |= q->nr_rqs_elvpriv; |
| drain |= q->request_fn_active; |
| |
| /* |
| * Unfortunately, requests are queued at and tracked from |
| * multiple places and there's no single counter which can |
| * be drained. Check all the queues and counters. |
| */ |
| if (drain_all) { |
| struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); |
| drain |= !list_empty(&q->queue_head); |
| for (i = 0; i < 2; i++) { |
| drain |= q->nr_rqs[i]; |
| drain |= q->in_flight[i]; |
| if (fq) |
| drain |= !list_empty(&fq->flush_queue[i]); |
| } |
| } |
| |
| if (!drain) |
| break; |
| |
| spin_unlock_irq(q->queue_lock); |
| |
| msleep(10); |
| |
| spin_lock_irq(q->queue_lock); |
| } |
| |
| /* |
| * With queue marked dead, any woken up waiter will fail the |
| * allocation path, so the wakeup chaining is lost and we're |
| * left with hung waiters. We need to wake up those waiters. |
| */ |
| if (q->request_fn) { |
| struct request_list *rl; |
| |
| blk_queue_for_each_rl(rl, q) |
| for (i = 0; i < ARRAY_SIZE(rl->wait); i++) |
| wake_up_all(&rl->wait[i]); |
| } |
| } |
| |
| void blk_drain_queue(struct request_queue *q) |
| { |
| spin_lock_irq(q->queue_lock); |
| __blk_drain_queue(q, true); |
| spin_unlock_irq(q->queue_lock); |
| } |
| |
| /** |
| * blk_queue_bypass_start - enter queue bypass mode |
| * @q: queue of interest |
| * |
| * In bypass mode, only the dispatch FIFO queue of @q is used. This |
| * function makes @q enter bypass mode and drains all requests which were |
| * throttled or issued before. On return, it's guaranteed that no request |
| * is being throttled or has ELVPRIV set and blk_queue_bypass() %true |
| * inside queue or RCU read lock. |
| */ |
| void blk_queue_bypass_start(struct request_queue *q) |
| { |
| WARN_ON_ONCE(q->mq_ops); |
| |
| spin_lock_irq(q->queue_lock); |
| q->bypass_depth++; |
| queue_flag_set(QUEUE_FLAG_BYPASS, q); |
| spin_unlock_irq(q->queue_lock); |
| |
| /* |
| * Queues start drained. Skip actual draining till init is |
| * complete. This avoids lenghty delays during queue init which |
| * can happen many times during boot. |
| */ |
| if (blk_queue_init_done(q)) { |
| spin_lock_irq(q->queue_lock); |
| __blk_drain_queue(q, false); |
| spin_unlock_irq(q->queue_lock); |
| |
| /* ensure blk_queue_bypass() is %true inside RCU read lock */ |
| synchronize_rcu(); |
| } |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_bypass_start); |
| |
| /** |
| * blk_queue_bypass_end - leave queue bypass mode |
| * @q: queue of interest |
| * |
| * Leave bypass mode and restore the normal queueing behavior. |
| * |
| * Note: although blk_queue_bypass_start() is only called for blk-sq queues, |
| * this function is called for both blk-sq and blk-mq queues. |
| */ |
| void blk_queue_bypass_end(struct request_queue *q) |
| { |
| spin_lock_irq(q->queue_lock); |
| if (!--q->bypass_depth) |
| queue_flag_clear(QUEUE_FLAG_BYPASS, q); |
| WARN_ON_ONCE(q->bypass_depth < 0); |
| spin_unlock_irq(q->queue_lock); |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_bypass_end); |
| |
| 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 (q->mq_ops) |
| blk_mq_wake_waiters(q); |
| else { |
| struct request_list *rl; |
| |
| spin_lock_irq(q->queue_lock); |
| blk_queue_for_each_rl(rl, q) { |
| if (rl->rq_pool) { |
| wake_up_all(&rl->wait[BLK_RW_SYNC]); |
| wake_up_all(&rl->wait[BLK_RW_ASYNC]); |
| } |
| } |
| spin_unlock_irq(q->queue_lock); |
| } |
| |
| /* Make blk_queue_enter() reexamine the DYING flag. */ |
| wake_up_all(&q->mq_freeze_wq); |
| } |
| EXPORT_SYMBOL_GPL(blk_set_queue_dying); |
| |
| /* Unconfigure the I/O scheduler and dissociate from the cgroup controller. */ |
| void blk_exit_queue(struct request_queue *q) |
| { |
| /* |
| * Since the I/O scheduler exit code may access cgroup information, |
| * perform I/O scheduler exit before disassociating from the block |
| * cgroup controller. |
| */ |
| if (q->elevator) { |
| ioc_clear_queue(q); |
| elevator_exit(q, q->elevator); |
| q->elevator = NULL; |
| } |
| |
| /* |
| * Remove all references to @q from the block cgroup controller before |
| * restoring @q->queue_lock to avoid that restoring this pointer causes |
| * e.g. blkcg_print_blkgs() to crash. |
| */ |
| blkcg_exit_queue(q); |
| |
| /* |
| * Since the cgroup code may dereference the @q->backing_dev_info |
| * pointer, only decrease its reference count after having removed the |
| * association with the block cgroup controller. |
| */ |
| bdi_put(q->backing_dev_info); |
| } |
| |
| /** |
| * 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) |
| { |
| spinlock_t *lock = q->queue_lock; |
| |
| /* mark @q DYING, no new request or merges will be allowed afterwards */ |
| mutex_lock(&q->sysfs_lock); |
| blk_set_queue_dying(q); |
| spin_lock_irq(lock); |
| |
| /* |
| * A dying queue is permanently in bypass mode till released. Note |
| * that, unlike blk_queue_bypass_start(), we aren't performing |
| * synchronize_rcu() after entering bypass mode to avoid the delay |
| * as some drivers create and destroy a lot of queues while |
| * probing. This is still safe because blk_release_queue() will be |
| * called only after the queue refcnt drops to zero and nothing, |
| * RCU or not, would be traversing the queue by then. |
| */ |
| q->bypass_depth++; |
| queue_flag_set(QUEUE_FLAG_BYPASS, q); |
| |
| queue_flag_set(QUEUE_FLAG_NOMERGES, q); |
| queue_flag_set(QUEUE_FLAG_NOXMERGES, q); |
| queue_flag_set(QUEUE_FLAG_DYING, q); |
| spin_unlock_irq(lock); |
| mutex_unlock(&q->sysfs_lock); |
| |
| /* |
| * Drain all requests queued before DYING marking. Set DEAD flag to |
| * prevent that q->request_fn() gets invoked after draining finished. |
| */ |
| blk_freeze_queue(q); |
| |
| rq_qos_exit(q); |
| |
| spin_lock_irq(lock); |
| queue_flag_set(QUEUE_FLAG_DEAD, q); |
| spin_unlock_irq(lock); |
| |
| /* |
| * make sure all in-progress dispatch are completed because |
| * blk_freeze_queue() can only complete all requests, and |
| * dispatch may still be in-progress since we dispatch requests |
| * from more than one contexts. |
| * |
| * We rely on driver to deal with the race in case that queue |
| * initialization isn't done. |
| */ |
| if (q->mq_ops && blk_queue_init_done(q)) |
| blk_mq_quiesce_queue(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); |
| |
| /* |
| * I/O scheduler exit is only safe after the sysfs scheduler attribute |
| * has been removed. |
| */ |
| WARN_ON_ONCE(q->kobj.state_in_sysfs); |
| |
| blk_exit_queue(q); |
| |
| if (q->mq_ops) |
| blk_mq_exit_queue(q); |
| |
| percpu_ref_exit(&q->q_usage_counter); |
| |
| spin_lock_irq(lock); |
| if (q->queue_lock != &q->__queue_lock) |
| q->queue_lock = &q->__queue_lock; |
| spin_unlock_irq(lock); |
| |
| /* @q is and will stay empty, shutdown and put */ |
| blk_put_queue(q); |
| } |
| EXPORT_SYMBOL(blk_cleanup_queue); |
| |
| /* Allocate memory local to the request queue */ |
| static void *alloc_request_simple(gfp_t gfp_mask, void *data) |
| { |
| struct request_queue *q = data; |
| |
| return kmem_cache_alloc_node(request_cachep, gfp_mask, q->node); |
| } |
| |
| static void free_request_simple(void *element, void *data) |
| { |
| kmem_cache_free(request_cachep, element); |
| } |
| |
| static void *alloc_request_size(gfp_t gfp_mask, void *data) |
| { |
| struct request_queue *q = data; |
| struct request *rq; |
| |
| rq = kmalloc_node(sizeof(struct request) + q->cmd_size, gfp_mask, |
| q->node); |
| if (rq && q->init_rq_fn && q->init_rq_fn(q, rq, gfp_mask) < 0) { |
| kfree(rq); |
| rq = NULL; |
| } |
| return rq; |
| } |
| |
| static void free_request_size(void *element, void *data) |
| { |
| struct request_queue *q = data; |
| |
| if (q->exit_rq_fn) |
| q->exit_rq_fn(q, element); |
| kfree(element); |
| } |
| |
| int blk_init_rl(struct request_list *rl, struct request_queue *q, |
| gfp_t gfp_mask) |
| { |
| if (unlikely(rl->rq_pool) || q->mq_ops) |
| return 0; |
| |
| rl->q = q; |
| rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0; |
| rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0; |
| init_waitqueue_head(&rl->wait[BLK_RW_SYNC]); |
| init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]); |
| |
| if (q->cmd_size) { |
| rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, |
| alloc_request_size, free_request_size, |
| q, gfp_mask, q->node); |
| } else { |
| rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, |
| alloc_request_simple, free_request_simple, |
| q, gfp_mask, q->node); |
| } |
| if (!rl->rq_pool) |
| return -ENOMEM; |
| |
| if (rl != &q->root_rl) |
| WARN_ON_ONCE(!blk_get_queue(q)); |
| |
| return 0; |
| } |
| |
| void blk_exit_rl(struct request_queue *q, struct request_list *rl) |
| { |
| if (rl->rq_pool) { |
| mempool_destroy(rl->rq_pool); |
| if (rl != &q->root_rl) |
| blk_put_queue(q); |
| } |
| } |
| |
| struct request_queue *blk_alloc_queue(gfp_t gfp_mask) |
| { |
| return blk_alloc_queue_node(gfp_mask, NUMA_NO_NODE, NULL); |
| } |
| 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, |
| (atomic_read(&q->mq_freeze_depth) == 0 && |
| (pm || !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_dummy(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 |
| * @lock: For legacy queues, pointer to a spinlock that will be used to e.g. |
| * serialize calls to the legacy .request_fn() callback. Ignored for |
| * blk-mq request queues. |
| * |
| * Note: pass the queue lock as the third argument to this function instead of |
| * setting the queue lock pointer explicitly to avoid triggering a sporadic |
| * crash in the blkcg code. This function namely calls blkcg_init_queue() and |
| * the queue lock pointer must be set before blkcg_init_queue() is called. |
| */ |
| struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id, |
| spinlock_t *lock) |
| { |
| struct request_queue *q; |
| int ret; |
| |
| q = kmem_cache_alloc_node(blk_requestq_cachep, |
| gfp_mask | __GFP_ZERO, node_id); |
| if (!q) |
| return NULL; |
| |
| INIT_LIST_HEAD(&q->queue_head); |
| q->last_merge = NULL; |
| q->end_sector = 0; |
| q->boundary_rq = 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_MAX_READAHEAD * 1024) / PAGE_SIZE; |
| 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_dummy); |
| INIT_LIST_HEAD(&q->timeout_list); |
| INIT_LIST_HEAD(&q->icq_list); |
| #ifdef CONFIG_BLK_CGROUP |
| INIT_LIST_HEAD(&q->blkg_list); |
| #endif |
| INIT_DELAYED_WORK(&q->delay_work, blk_delay_work); |
| |
| 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); |
| spin_lock_init(&q->__queue_lock); |
| |
| if (!q->mq_ops) |
| q->queue_lock = lock ? : &q->__queue_lock; |
| |
| /* |
| * A queue starts its life with bypass turned on to avoid |
| * unnecessary bypass on/off overhead and nasty surprises during |
| * init. The initial bypass will be finished when the queue is |
| * registered by blk_register_queue(). |
| */ |
| q->bypass_depth = 1; |
| queue_flag_set_unlocked(QUEUE_FLAG_BYPASS, q); |
| |
| init_waitqueue_head(&q->mq_freeze_wq); |
| |
| /* |
| * 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); |
| |
| /** |
| * blk_init_queue - prepare a request queue for use with a block device |
| * @rfn: The function to be called to process requests that have been |
| * placed on the queue. |
| * @lock: Request queue spin lock |
| * |
| * Description: |
| * If a block device wishes to use the standard request handling procedures, |
| * which sorts requests and coalesces adjacent requests, then it must |
| * call blk_init_queue(). The function @rfn will be called when there |
| * are requests on the queue that need to be processed. If the device |
| * supports plugging, then @rfn may not be called immediately when requests |
| * are available on the queue, but may be called at some time later instead. |
| * Plugged queues are generally unplugged when a buffer belonging to one |
| * of the requests on the queue is needed, or due to memory pressure. |
| * |
| * @rfn is not required, or even expected, to remove all requests off the |
| * queue, but only as many as it can handle at a time. If it does leave |
| * requests on the queue, it is responsible for arranging that the requests |
| * get dealt with eventually. |
| * |
| * The queue spin lock must be held while manipulating the requests on the |
| * request queue; this lock will be taken also from interrupt context, so irq |
| * disabling is needed for it. |
| * |
| * Function returns a pointer to the initialized request queue, or %NULL if |
| * it didn't succeed. |
| * |
| * Note: |
| * blk_init_queue() must be paired with a blk_cleanup_queue() call |
| * when the block device is deactivated (such as at module unload). |
| **/ |
| |
| struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock) |
| { |
| return blk_init_queue_node(rfn, lock, NUMA_NO_NODE); |
| } |
| EXPORT_SYMBOL(blk_init_queue); |
| |
| struct request_queue * |
| blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id) |
| { |
| struct request_queue *q; |
| |
| q = blk_alloc_queue_node(GFP_KERNEL, node_id, lock); |
| if (!q) |
| return NULL; |
| |
| q->request_fn = rfn; |
| if (blk_init_allocated_queue(q) < 0) { |
| blk_cleanup_queue(q); |
| return NULL; |
| } |
| |
| return q; |
| } |
| EXPORT_SYMBOL(blk_init_queue_node); |
| |
| static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio); |
| |
| |
| int blk_init_allocated_queue(struct request_queue *q) |
| { |
| WARN_ON_ONCE(q->mq_ops); |
| |
| q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, q->cmd_size, GFP_KERNEL); |
| if (!q->fq) |
| return -ENOMEM; |
| |
| if (q->init_rq_fn && q->init_rq_fn(q, q->fq->flush_rq, GFP_KERNEL)) |
| goto out_free_flush_queue; |
| |
| if (blk_init_rl(&q->root_rl, q, GFP_KERNEL)) |
| goto out_exit_flush_rq; |
| |
| INIT_WORK(&q->timeout_work, blk_timeout_work); |
| q->queue_flags |= QUEUE_FLAG_DEFAULT; |
| |
| /* |
| * This also sets hw/phys segments, boundary and size |
| */ |
| blk_queue_make_request(q, blk_queue_bio); |
| |
| q->sg_reserved_size = INT_MAX; |
| |
| if (elevator_init(q)) |
| goto out_exit_flush_rq; |
| return 0; |
| |
| out_exit_flush_rq: |
| if (q->exit_rq_fn) |
| q->exit_rq_fn(q, q->fq->flush_rq); |
| out_free_flush_queue: |
| blk_free_flush_queue(q->fq); |
| q->fq = NULL; |
| return -ENOMEM; |
| } |
| EXPORT_SYMBOL(blk_init_allocated_queue); |
| |
| 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); |
| |
| static inline void blk_free_request(struct request_list *rl, struct request *rq) |
| { |
| if (rq->rq_flags & RQF_ELVPRIV) { |
| elv_put_request(rl->q, rq); |
| if (rq->elv.icq) |
| put_io_context(rq->elv.icq->ioc); |
| } |
| |
| mempool_free(rq, rl->rq_pool); |
| } |
| |
| /* |
| * ioc_batching returns true if the ioc is a valid batching request and |
| * should be given priority access to a request. |
| */ |
| static inline int ioc_batching(struct request_queue *q, struct io_context *ioc) |
| { |
| if (!ioc) |
| return 0; |
| |
| /* |
| * Make sure the process is able to allocate at least 1 request |
| * even if the batch times out, otherwise we could theoretically |
| * lose wakeups. |
| */ |
| return ioc->nr_batch_requests == q->nr_batching || |
| (ioc->nr_batch_requests > 0 |
| && time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME)); |
| } |
| |
| /* |
| * ioc_set_batching sets ioc to be a new "batcher" if it is not one. This |
| * will cause the process to be a "batcher" on all queues in the system. This |
| * is the behaviour we want though - once it gets a wakeup it should be given |
| * a nice run. |
| */ |
| static void ioc_set_batching(struct request_queue *q, struct io_context *ioc) |
| { |
| if (!ioc || ioc_batching(q, ioc)) |
| return; |
| |
| ioc->nr_batch_requests = q->nr_batching; |
| ioc->last_waited = jiffies; |
| } |
| |
| static void __freed_request(struct request_list *rl, int sync) |
| { |
| struct request_queue *q = rl->q; |
| |
| if (rl->count[sync] < queue_congestion_off_threshold(q)) |
| blk_clear_congested(rl, sync); |
| |
| if (rl->count[sync] + 1 <= q->nr_requests) { |
| if (waitqueue_active(&rl->wait[sync])) |
| wake_up(&rl->wait[sync]); |
| |
| blk_clear_rl_full(rl, sync); |
| } |
| } |
| |
| /* |
| * A request has just been released. Account for it, update the full and |
| * congestion status, wake up any waiters. Called under q->queue_lock. |
| */ |
| static void freed_request(struct request_list *rl, bool sync, |
| req_flags_t rq_flags) |
| { |
| struct request_queue *q = rl->q; |
| |
| q->nr_rqs[sync]--; |
| rl->count[sync]--; |
| if (rq_flags & RQF_ELVPRIV) |
| q->nr_rqs_elvpriv--; |
| |
| __freed_request(rl, sync); |
| |
| if (unlikely(rl->starved[sync ^ 1])) |
| __freed_request(rl, sync ^ 1); |
| } |
| |
| int blk_update_nr_requests(struct request_queue *q, unsigned int nr) |
| { |
| struct request_list *rl; |
| int on_thresh, off_thresh; |
| |
| WARN_ON_ONCE(q->mq_ops); |
| |
| spin_lock_irq(q->queue_lock); |
| q->nr_requests = nr; |
| blk_queue_congestion_threshold(q); |
| on_thresh = queue_congestion_on_threshold(q); |
| off_thresh = queue_congestion_off_threshold(q); |
| |
| blk_queue_for_each_rl(rl, q) { |
| if (rl->count[BLK_RW_SYNC] >= on_thresh) |
| blk_set_congested(rl, BLK_RW_SYNC); |
| else if (rl->count[BLK_RW_SYNC] < off_thresh) |
| blk_clear_congested(rl, BLK_RW_SYNC); |
| |
| if (rl->count[BLK_RW_ASYNC] >= on_thresh) |
| blk_set_congested(rl, BLK_RW_ASYNC); |
| else if (rl->count[BLK_RW_ASYNC] < off_thresh) |
| blk_clear_congested(rl, BLK_RW_ASYNC); |
| |
| if (rl->count[BLK_RW_SYNC] >= q->nr_requests) { |
| blk_set_rl_full(rl, BLK_RW_SYNC); |
| } else { |
| blk_clear_rl_full(rl, BLK_RW_SYNC); |
| wake_up(&rl->wait[BLK_RW_SYNC]); |
| } |
| |
| if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) { |
| blk_set_rl_full(rl, BLK_RW_ASYNC); |
| } else { |
| blk_clear_rl_full(rl, BLK_RW_ASYNC); |
| wake_up(&rl->wait[BLK_RW_ASYNC]); |
| } |
| } |
| |
| spin_unlock_irq(q->queue_lock); |
| return 0; |
| } |
| |
| /** |
| * __get_request - get a free request |
| * @rl: request list to allocate from |
| * @op: operation and flags |
| * @bio: bio to allocate request for (can be %NULL) |
| * @flags: BLQ_MQ_REQ_* flags |
| * @gfp_mask: allocator flags |
| * |
| * Get a free request from @q. This function may fail under memory |
| * pressure or if @q is dead. |
| * |
| * Must be called with @q->queue_lock held and, |
| * Returns ERR_PTR on failure, with @q->queue_lock held. |
| * Returns request pointer on success, with @q->queue_lock *not held*. |
| */ |
| static struct request *__get_request(struct request_list *rl, unsigned int op, |
| struct bio *bio, blk_mq_req_flags_t flags, gfp_t gfp_mask) |
| { |
| struct request_queue *q = rl->q; |
| struct request *rq; |
| struct elevator_type *et = q->elevator->type; |
| struct io_context *ioc = rq_ioc(bio); |
| struct io_cq *icq = NULL; |
| const bool is_sync = op_is_sync(op); |
| int may_queue; |
| req_flags_t rq_flags = RQF_ALLOCED; |
| |
| lockdep_assert_held(q->queue_lock); |
| |
| if (unlikely(blk_queue_dying(q))) |
| return ERR_PTR(-ENODEV); |
| |
| may_queue = elv_may_queue(q, op); |
| if (may_queue == ELV_MQUEUE_NO) |
| goto rq_starved; |
| |
| if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) { |
| if (rl->count[is_sync]+1 >= q->nr_requests) { |
| /* |
| * The queue will fill after this allocation, so set |
| * it as full, and mark this process as "batching". |
| * This process will be allowed to complete a batch of |
| * requests, others will be blocked. |
| */ |
| if (!blk_rl_full(rl, is_sync)) { |
| ioc_set_batching(q, ioc); |
| blk_set_rl_full(rl, is_sync); |
| } else { |
| if (may_queue != ELV_MQUEUE_MUST |
| && !ioc_batching(q, ioc)) { |
| /* |
| * The queue is full and the allocating |
| * process is not a "batcher", and not |
| * exempted by the IO scheduler |
| */ |
| return ERR_PTR(-ENOMEM); |
| } |
| } |
| } |
| blk_set_congested(rl, is_sync); |
| } |
| |
| /* |
| * Only allow batching queuers to allocate up to 50% over the defined |
| * limit of requests, otherwise we could have thousands of requests |
| * allocated with any setting of ->nr_requests |
| */ |
| if (rl->count[is_sync] >= (3 * q->nr_requests / 2)) |
| return ERR_PTR(-ENOMEM); |
| |
| q->nr_rqs[is_sync]++; |
| rl->count[is_sync]++; |
| rl->starved[is_sync] = 0; |
| |
| /* |
| * Decide whether the new request will be managed by elevator. If |
| * so, mark @rq_flags and increment elvpriv. Non-zero elvpriv will |
| * prevent the current elevator from being destroyed until the new |
| * request is freed. This guarantees icq's won't be destroyed and |
| * makes creating new ones safe. |
| * |
| * Flush requests do not use the elevator so skip initialization. |
| * This allows a request to share the flush and elevator data. |
| * |
| * Also, lookup icq while holding queue_lock. If it doesn't exist, |
| * it will be created after releasing queue_lock. |
| */ |
| if (!op_is_flush(op) && !blk_queue_bypass(q)) { |
| rq_flags |= RQF_ELVPRIV; |
| q->nr_rqs_elvpriv++; |
| if (et->icq_cache && ioc) |
| icq = ioc_lookup_icq(ioc, q); |
| } |
| |
| if (blk_queue_io_stat(q)) |
| rq_flags |= RQF_IO_STAT; |
| spin_unlock_irq(q->queue_lock); |
| |
| /* allocate and init request */ |
| rq = mempool_alloc(rl->rq_pool, gfp_mask); |
| if (!rq) |
| goto fail_alloc; |
| |
| blk_rq_init(q, rq); |
| blk_rq_set_rl(rq, rl); |
| rq->cmd_flags = op; |
| rq->rq_flags = rq_flags; |
| if (flags & BLK_MQ_REQ_PREEMPT) |
| rq->rq_flags |= RQF_PREEMPT; |
| |
| /* init elvpriv */ |
| if (rq_flags & RQF_ELVPRIV) { |
| if (unlikely(et->icq_cache && !icq)) { |
| if (ioc) |
| icq = ioc_create_icq(ioc, q, gfp_mask); |
| if (!icq) |
| goto fail_elvpriv; |
| } |
| |
| rq->elv.icq = icq; |
| if (unlikely(elv_set_request(q, rq, bio, gfp_mask))) |
| goto fail_elvpriv; |
| |
| /* @rq->elv.icq holds io_context until @rq is freed */ |
| if (icq) |
| get_io_context(icq->ioc); |
| } |
| out: |
| /* |
| * ioc may be NULL here, and ioc_batching will be false. That's |
| * OK, if the queue is under the request limit then requests need |
| * not count toward the nr_batch_requests limit. There will always |
| * be some limit enforced by BLK_BATCH_TIME. |
| */ |
| if (ioc_batching(q, ioc)) |
| ioc->nr_batch_requests--; |
| |
| trace_block_getrq(q, bio, op); |
| return rq; |
| |
| fail_elvpriv: |
| /* |
| * elvpriv init failed. ioc, icq and elvpriv aren't mempool backed |
| * and may fail indefinitely under memory pressure and thus |
| * shouldn't stall IO. Treat this request as !elvpriv. This will |
| * disturb iosched and blkcg but weird is bettern than dead. |
| */ |
| printk_ratelimited(KERN_WARNING "%s: dev %s: request aux data allocation failed, iosched may be disturbed\n", |
| __func__, dev_name(q->backing_dev_info->dev)); |
| |
| rq->rq_flags &= ~RQF_ELVPRIV; |
| rq->elv.icq = NULL; |
| |
| spin_lock_irq(q->queue_lock); |
| q->nr_rqs_elvpriv--; |
| spin_unlock_irq(q->queue_lock); |
| goto out; |
| |
| fail_alloc: |
| /* |
| * Allocation failed presumably due to memory. Undo anything we |
| * might have messed up. |
| * |
| * Allocating task should really be put onto the front of the wait |
| * queue, but this is pretty rare. |
| */ |
| spin_lock_irq(q->queue_lock); |
| freed_request(rl, is_sync, rq_flags); |
| |
| /* |
| * in the very unlikely event that allocation failed and no |
| * requests for this direction was pending, mark us starved so that |
| * freeing of a request in the other direction will notice |
| * us. another possible fix would be to split the rq mempool into |
| * READ and WRITE |
| */ |
| rq_starved: |
| if (unlikely(rl->count[is_sync] == 0)) |
| rl->starved[is_sync] = 1; |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| /** |
| * get_request - get a free request |
| * @q: request_queue to allocate request from |
| * @op: operation and flags |
| * @bio: bio to allocate request for (can be %NULL) |
| * @flags: BLK_MQ_REQ_* flags. |
| * @gfp: allocator flags |
| * |
| * Get a free request from @q. If %BLK_MQ_REQ_NOWAIT is set in @flags, |
| * this function keeps retrying under memory pressure and fails iff @q is dead. |
| * |
| * Must be called with @q->queue_lock held and, |
| * Returns ERR_PTR on failure, with @q->queue_lock held. |
| * Returns request pointer on success, with @q->queue_lock *not held*. |
| */ |
| static struct request *get_request(struct request_queue *q, unsigned int op, |
| struct bio *bio, blk_mq_req_flags_t flags, gfp_t gfp) |
| { |
| const bool is_sync = op_is_sync(op); |
| DEFINE_WAIT(wait); |
| struct request_list *rl; |
| struct request *rq; |
| |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| rl = blk_get_rl(q, bio); /* transferred to @rq on success */ |
| retry: |
| rq = __get_request(rl, op, bio, flags, gfp); |
| if (!IS_ERR(rq)) |
| return rq; |
| |
| if (op & REQ_NOWAIT) { |
| blk_put_rl(rl); |
| return ERR_PTR(-EAGAIN); |
| } |
| |
| if ((flags & BLK_MQ_REQ_NOWAIT) || unlikely(blk_queue_dying(q))) { |
| blk_put_rl(rl); |
| return rq; |
| } |
| |
| /* wait on @rl and retry */ |
| prepare_to_wait_exclusive(&rl->wait[is_sync], &wait, |
| TASK_UNINTERRUPTIBLE); |
| |
| trace_block_sleeprq(q, bio, op); |
| |
| spin_unlock_irq(q->queue_lock); |
| io_schedule(); |
| |
| /* |
| * After sleeping, we become a "batching" process and will be able |
| * to allocate at least one request, and up to a big batch of them |
| * for a small period time. See ioc_batching, ioc_set_batching |
| */ |
| ioc_set_batching(q, current->io_context); |
| |
| spin_lock_irq(q->queue_lock); |
| finish_wait(&rl->wait[is_sync], &wait); |
| |
| goto retry; |
| } |
| |
| /* flags: BLK_MQ_REQ_PREEMPT and/or BLK_MQ_REQ_NOWAIT. */ |
| static struct request *blk_old_get_request(struct request_queue *q, |
| unsigned int op, blk_mq_req_flags_t flags) |
| { |
| struct request *rq; |
| gfp_t gfp_mask = flags & BLK_MQ_REQ_NOWAIT ? GFP_ATOMIC : GFP_NOIO; |
| int ret = 0; |
| |
| WARN_ON_ONCE(q->mq_ops); |
| |
| /* create ioc upfront */ |
| create_io_context(gfp_mask, q->node); |
| |
| ret = blk_queue_enter(q, flags); |
| if (ret) |
| return ERR_PTR(ret); |
| spin_lock_irq(q->queue_lock); |
| rq = get_request(q, op, NULL, flags, gfp_mask); |
| if (IS_ERR(rq)) { |
| spin_unlock_irq(q->queue_lock); |
| blk_queue_exit(q); |
| return rq; |
| } |
| |
| /* q->queue_lock is unlocked at this point */ |
| rq->__data_len = 0; |
| rq->__sector = (sector_t) -1; |
| rq->bio = rq->biotail = NULL; |
| return rq; |
| } |
| |
| /** |
| * 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)); |
| |
| if (q->mq_ops) { |
| 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); |
| } else { |
| req = blk_old_get_request(q, op, flags); |
| if (!IS_ERR(req) && q->initialize_rq_fn) |
| q->initialize_rq_fn(req); |
| } |
| |
| return req; |
| } |
| EXPORT_SYMBOL(blk_get_request); |
| |
| /** |
| * blk_requeue_request - put a request back on queue |
| * @q: request queue where request should be inserted |
| * @rq: request to be inserted |
| * |
| * Description: |
| * Drivers often keep queueing requests until the hardware cannot accept |
| * more, when that condition happens we need to put the request back |
| * on the queue. Must be called with queue lock held. |
| */ |
| void blk_requeue_request(struct request_queue *q, struct request *rq) |
| { |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| blk_delete_timer(rq); |
| blk_clear_rq_complete(rq); |
| trace_block_rq_requeue(q, rq); |
| rq_qos_requeue(q, rq); |
| |
| if (rq->rq_flags & RQF_QUEUED) |
| blk_queue_end_tag(q, rq); |
| |
| BUG_ON(blk_queued_rq(rq)); |
| |
| elv_requeue_request(q, rq); |
| } |
| EXPORT_SYMBOL(blk_requeue_request); |
| |
| static void add_acct_request(struct request_queue *q, struct request *rq, |
| int where) |
| { |
| blk_account_io_start(rq, true); |
| __elv_add_request(q, rq, where); |
| } |
| |
| static void part_round_stats_single(struct request_queue *q, int cpu, |
| struct hd_struct *part, unsigned long now, |
| unsigned int inflight) |
| { |
| if (inflight) { |
| __part_stat_add(cpu, part, time_in_queue, |
| inflight * (now - part->stamp)); |
| __part_stat_add(cpu, part, io_ticks, (now - part->stamp)); |
| } |
| part->stamp = now; |
| } |
| |
| /** |
| * part_round_stats() - Round off the performance stats on a struct disk_stats. |
| * @q: target block queue |
| * @cpu: cpu number for stats access |
| * @part: target partition |
| * |
| * The average IO queue length and utilisation statistics are maintained |
| * by observing the current state of the queue length and the amount of |
| * time it has been in this state for. |
| * |
| * Normally, that accounting is done on IO completion, but that can result |
| * in more than a second's worth of IO being accounted for within any one |
| * second, leading to >100% utilisation. To deal with that, we call this |
| * function to do a round-off before returning the results when reading |
| * /proc/diskstats. This accounts immediately for all queue usage up to |
| * the current jiffies and restarts the counters again. |
| */ |
| void part_round_stats(struct request_queue *q, int cpu, struct hd_struct *part) |
| { |
| struct hd_struct *part2 = NULL; |
| unsigned long now = jiffies; |
| unsigned int inflight[2]; |
| int stats = 0; |
| |
| if (part->stamp != now) |
| stats |= 1; |
| |
| if (part->partno) { |
| part2 = &part_to_disk(part)->part0; |
| if (part2->stamp != now) |
| stats |= 2; |
| } |
| |
| if (!stats) |
| return; |
| |
| part_in_flight(q, part, inflight); |
| |
| if (stats & 2) |
| part_round_stats_single(q, cpu, part2, now, inflight[1]); |
| if (stats & 1) |
| part_round_stats_single(q, cpu, part, now, inflight[0]); |
| } |
| EXPORT_SYMBOL_GPL(part_round_stats); |
| |
| #ifdef CONFIG_PM |
| static void blk_pm_put_request(struct request *rq) |
| { |
| if (rq->q->dev && !(rq->rq_flags & RQF_PM) && !--rq->q->nr_pending) |
| pm_runtime_mark_last_busy(rq->q->dev); |
| } |
| #else |
| static inline void blk_pm_put_request(struct request *rq) {} |
| #endif |
| |
| void __blk_put_request(struct request_queue *q, struct request *req) |
| { |
| req_flags_t rq_flags = req->rq_flags; |
| |
| if (unlikely(!q)) |
| return; |
| |
| if (q->mq_ops) { |
| blk_mq_free_request(req); |
| return; |
| } |
| |
| lockdep_assert_held(q->queue_lock); |
| |
| blk_req_zone_write_unlock(req); |
| blk_pm_put_request(req); |
| |
| elv_completed_request(q, req); |
| |
| /* this is a bio leak */ |
| WARN_ON(req->bio != NULL); |
| |
| rq_qos_done(q, req); |
| |
| /* |
| * Request may not have originated from ll_rw_blk. if not, |
| * it didn't come out of our reserved rq pools |
| */ |
| if (rq_flags & RQF_ALLOCED) { |
| struct request_list *rl = blk_rq_rl(req); |
| bool sync = op_is_sync(req->cmd_flags); |
| |
| BUG_ON(!list_empty(&req->queuelist)); |
| BUG_ON(ELV_ON_HASH(req)); |
| |
| blk_free_request(rl, req); |
| freed_request(rl, sync, rq_flags); |
| blk_put_rl(rl); |
| blk_queue_exit(q); |
| } |
| } |
| EXPORT_SYMBOL_GPL(__blk_put_request); |
| |
| void blk_put_request(struct request *req) |
| { |
| struct request_queue *q = req->q; |
| |
| if (q->mq_ops) |
| blk_mq_free_request(req); |
| else { |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| __blk_put_request(q, req); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| } |
| EXPORT_SYMBOL(blk_put_request); |
| |
| bool bio_attempt_back_merge(struct request_queue *q, struct request *req, |
| struct bio *bio) |
| { |
| const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
| |
| if (!ll_back_merge_fn(q, req, bio)) |
| return false; |
| |
| trace_block_bio_backmerge(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; |
| req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
| |
| blk_account_io_start(req, false); |
| return true; |
| } |
| |
| bool bio_attempt_front_merge(struct request_queue *q, struct request *req, |
| struct bio *bio) |
| { |
| const int ff = bio->bi_opf & REQ_FAILFAST_MASK; |
| |
| if (!ll_front_merge_fn(q, req, bio)) |
| return false; |
| |
| trace_block_bio_frontmerge(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; |
| req->ioprio = ioprio_best(req->ioprio, bio_prio(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; |
| |
| req->biotail->bi_next = bio; |
| req->biotail = bio; |
| req->__data_len += bio->bi_iter.bi_size; |
| req->ioprio = ioprio_best(req->ioprio, bio_prio(bio)); |
| 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 |
| * @request_count: out parameter for number of traversed plugged requests |
| * @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 *request_count, |
| struct request **same_queue_rq) |
| { |
| struct blk_plug *plug; |
| struct request *rq; |
| struct list_head *plug_list; |
| |
| plug = current->plug; |
| if (!plug) |
| return false; |
| *request_count = 0; |
| |
| if (q->mq_ops) |
| plug_list = &plug->mq_list; |
| else |
| plug_list = &plug->list; |
| |
| list_for_each_entry_reverse(rq, plug_list, queuelist) { |
| bool merged = false; |
| |
| if (rq->q == q) { |
| (*request_count)++; |
| /* |
| * Only blk-mq multiple hardware queues case checks the |
| * rq in the same queue, there should be only one such |
| * rq in a queue |
| **/ |
| if (same_queue_rq) |
| *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(q, rq, bio); |
| break; |
| case ELEVATOR_FRONT_MERGE: |
| merged = bio_attempt_front_merge(q, rq, bio); |
| break; |
| case ELEVATOR_DISCARD_MERGE: |
| merged = bio_attempt_discard_merge(q, rq, bio); |
| break; |
| default: |
| break; |
| } |
| |
| if (merged) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| unsigned int blk_plug_queued_count(struct request_queue *q) |
| { |
| struct blk_plug *plug; |
| struct request *rq; |
| struct list_head *plug_list; |
| unsigned int ret = 0; |
| |
| plug = current->plug; |
| if (!plug) |
| goto out; |
| |
| if (q->mq_ops) |
| plug_list = &plug->mq_list; |
| else |
| plug_list = &plug->list; |
| |
| list_for_each_entry(rq, plug_list, queuelist) { |
| if (rq->q == q) |
| ret++; |
| } |
| out: |
| return ret; |
| } |
| |
| void blk_init_request_from_bio(struct request *req, struct bio *bio) |
| { |
| struct io_context *ioc = rq_ioc(bio); |
| |
| if (bio->bi_opf & REQ_RAHEAD) |
| req->cmd_flags |= REQ_FAILFAST_MASK; |
| |
| req->__sector = bio->bi_iter.bi_sector; |
| if (ioprio_valid(bio_prio(bio))) |
| req->ioprio = bio_prio(bio); |
| else if (ioc) |
| req->ioprio = ioc->ioprio; |
| else |
| req->ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); |
| req->write_hint = bio->bi_write_hint; |
| blk_rq_bio_prep(req->q, req, bio); |
| } |
| EXPORT_SYMBOL_GPL(blk_init_request_from_bio); |
| |
| static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) |
| { |
| struct blk_plug *plug; |
| int where = ELEVATOR_INSERT_SORT; |
| struct request *req, *free; |
| unsigned int request_count = 0; |
| |
| /* |
| * low level driver can indicate that it wants pages above a |
| * certain limit bounced to low memory (ie for highmem, or even |
| * ISA dma in theory) |
| */ |
| blk_queue_bounce(q, &bio); |
| |
| blk_queue_split(q, &bio); |
| |
| if (!bio_integrity_prep(bio)) |
| return BLK_QC_T_NONE; |
| |
| if (op_is_flush(bio->bi_opf)) { |
| spin_lock_irq(q->queue_lock); |
| where = ELEVATOR_INSERT_FLUSH; |
| goto get_rq; |
| } |
| |
| /* |
| * Check if we can merge with the plugged list before grabbing |
| * any locks. |
| */ |
| if (!blk_queue_nomerges(q)) { |
| if (blk_attempt_plug_merge(q, bio, &request_count, NULL)) |
| return BLK_QC_T_NONE; |
| } else |
| request_count = blk_plug_queued_count(q); |
| |
| spin_lock_irq(q->queue_lock); |
| |
| switch (elv_merge(q, &req, bio)) { |
| case ELEVATOR_BACK_MERGE: |
| if (!bio_attempt_back_merge(q, req, bio)) |
| break; |
| elv_bio_merged(q, req, bio); |
| free = attempt_back_merge(q, req); |
| if (free) |
| __blk_put_request(q, free); |
| else |
| elv_merged_request(q, req, ELEVATOR_BACK_MERGE); |
| goto out_unlock; |
| case ELEVATOR_FRONT_MERGE: |
| if (!bio_attempt_front_merge(q, req, bio)) |
| break; |
| elv_bio_merged(q, req, bio); |
| free = attempt_front_merge(q, req); |
| if (free) |
| __blk_put_request(q, free); |
| else |
| elv_merged_request(q, req, ELEVATOR_FRONT_MERGE); |
| goto out_unlock; |
| default: |
| break; |
| } |
| |
| get_rq: |
| rq_qos_throttle(q, bio, q->queue_lock); |
| |
| /* |
| * Grab a free request. This is might sleep but can not fail. |
| * Returns with the queue unlocked. |
| */ |
| blk_queue_enter_live(q); |
| req = get_request(q, bio->bi_opf, bio, 0, GFP_NOIO); |
| if (IS_ERR(req)) { |
| blk_queue_exit(q); |
| rq_qos_cleanup(q, bio); |
| if (PTR_ERR(req) == -ENOMEM) |
| bio->bi_status = BLK_STS_RESOURCE; |
| else |
| bio->bi_status = BLK_STS_IOERR; |
| bio_endio(bio); |
| goto out_unlock; |
| } |
| |
| rq_qos_track(q, req, bio); |
| |
| /* |
| * After dropping the lock and possibly sleeping here, our request |
| * may now be mergeable after it had proven unmergeable (above). |
| * We don't worry about that case for efficiency. It won't happen |
| * often, and the elevators are able to handle it. |
| */ |
| blk_init_request_from_bio(req, bio); |
| |
| if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) |
| req->cpu = raw_smp_processor_id(); |
| |
| plug = current->plug; |
| if (plug) { |
| /* |
| * If this is the first request added after a plug, fire |
| * of a plug trace. |
| * |
| * @request_count may become stale because of schedule |
| * out, so check plug list again. |
| */ |
| if (!request_count || list_empty(&plug->list)) |
| trace_block_plug(q); |
| else { |
| struct request *last = list_entry_rq(plug->list.prev); |
| if (request_count >= BLK_MAX_REQUEST_COUNT || |
| blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE) { |
| blk_flush_plug_list(plug, false); |
| trace_block_plug(q); |
| } |
| } |
| list_add_tail(&req->queuelist, &plug->list); |
| blk_account_io_start(req, true); |
| } else { |
| spin_lock_irq(q->queue_lock); |
| add_acct_request(q, req, where); |
| __blk_run_queue(q); |
| out_unlock: |
| spin_unlock_irq(q->queue_lock); |
| } |
| |
| return BLK_QC_T_NONE; |
| } |
| |
| static void handle_bad_sector(struct bio *bio, sector_t maxsector) |
| { |
| char b[BDEVNAME_SIZE]; |
| |
| printk(KERN_INFO "attempt to access beyond end of device\n"); |
| printk(KERN_INFO "%s: rw=%d, want=%Lu, limit=%Lu\n", |
| bio_devname(bio, b), bio->bi_opf, |
| (unsigned long long)bio_end_sector(bio), |
| (long long)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; |
| |
| /* |
| * Zone reset does not include bi_size so bio_sectors() is always 0. |
| * Include a test for the reset op code and perform the remap if needed. |
| */ |
| if (bio_sectors(bio) || bio_op(bio) == REQ_OP_ZONE_RESET) { |
| 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; |
| } |
| |
| /* |
| * For a REQ_NOWAIT based request, return -EOPNOTSUPP |
| * if queue is not a request based queue. |
| */ |
| if ((bio->bi_opf & REQ_NOWAIT) && !queue_is_rq_based(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 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; |
| } |
| } |
| |
| 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_REPORT: |
| case REQ_OP_ZONE_RESET: |
| if (!blk_queue_is_zoned(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_mq_req_flags_t flags = 0; |
| struct request_queue *q = bio->bi_disk->queue; |
| blk_qc_t ret = BLK_QC_T_NONE; |
| |
| if (bio->bi_opf & REQ_NOWAIT) |
| flags = BLK_MQ_REQ_NOWAIT; |
| if (bio_flagged(bio, BIO_QUEUE_ENTERED)) |
| blk_queue_enter_live(q); |
| else if (blk_queue_enter(q, flags) < 0) { |
| if (!blk_queue_dying(q) && (bio->bi_opf & REQ_NOWAIT)) |
| bio_wouldblock_error(bio); |
| else |
| bio_io_error(bio); |
| return ret; |
| } |
| |
| 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 { |
| bool enter_succeeded = true; |
| |
| if (unlikely(q != bio->bi_disk->queue)) { |
| if (q) |
| blk_queue_exit(q); |
| q = bio->bi_disk->queue; |
| flags = 0; |
| if (bio->bi_opf & REQ_NOWAIT) |
| flags = BLK_MQ_REQ_NOWAIT; |
| if (blk_queue_enter(q, flags) < 0) |
| enter_succeeded = false; |
| } |
| |
| if (enter_succeeded) { |
| 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]); |
| ret = q->make_request_fn(q, 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]); |
| } else { |
| if (unlikely(!blk_queue_dying(q) && |
| (bio->bi_opf & REQ_NOWAIT))) |
| bio_wouldblock_error(bio); |
| else |
| bio_io_error(bio); |
| q = NULL; |
| } |
| bio = bio_list_pop(&bio_list_on_stack[0]); |
| } while (bio); |
| current->bio_list = NULL; /* deactivate */ |
| |
| out: |
| if (q) |
| blk_queue_exit(q); |
| 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; |
| |
| 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; |
| } |
| |
| 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) |
| { |
| /* |
| * 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); |
| } |
| } |
| |
| return generic_make_request(bio); |
| } |
| EXPORT_SYMBOL(submit_bio); |
| |
| bool blk_poll(struct request_queue *q, blk_qc_t cookie) |
| { |
| if (!q->poll_fn || !blk_qc_t_valid(cookie)) |
| return false; |
| |
| if (current->plug) |
| blk_flush_plug_list(current->plug, false); |
| return q->poll_fn(q, cookie); |
| } |
| EXPORT_SYMBOL_GPL(blk_poll); |
| |
| /** |
| * 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.\n", __func__); |
| 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. |
| */ |
| blk_recalc_rq_segments(rq); |
| if (rq->nr_phys_segments > queue_max_segments(q)) { |
| printk(KERN_ERR "%s: over max segments limit.\n", __func__); |
| 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) |
| { |
| unsigned long flags; |
| int where = ELEVATOR_INSERT_BACK; |
| |
| 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 (q->mq_ops) { |
| 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); |
| } |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| if (unlikely(blk_queue_dying(q))) { |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| return BLK_STS_IOERR; |
| } |
| |
| /* |
| * Submitting request must be dequeued before calling this function |
| * because it will be linked to another request_queue |
| */ |
| BUG_ON(blk_queued_rq(rq)); |
| |
| if (op_is_flush(rq->cmd_flags)) |
| where = ELEVATOR_INSERT_FLUSH; |
| |
| add_acct_request(q, rq, where); |
| if (where == ELEVATOR_INSERT_FLUSH) |
| __blk_run_queue(q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| return BLK_STS_OK; |
| } |
| 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; |
| int cpu; |
| |
| cpu = part_stat_lock(); |
| part = req->part; |
| part_stat_add(cpu, 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; |
| int cpu; |
| |
| cpu = part_stat_lock(); |
| part = req->part; |
| |
| part_stat_inc(cpu, part, ios[sgrp]); |
| part_stat_add(cpu, part, nsecs[sgrp], now - req->start_time_ns); |
| part_round_stats(req->q, cpu, part); |
| part_dec_in_flight(req->q, part, rq_data_dir(req)); |
| |
| hd_struct_put(part); |
| part_stat_unlock(); |
| } |
| } |
| |
| #ifdef CONFIG_PM |
| /* |
| * Don't process normal requests when queue is suspended |
| * or in the process of suspending/resuming |
| */ |
| static bool blk_pm_allow_request(struct request *rq) |
| { |
| switch (rq->q->rpm_status) { |
| case RPM_RESUMING: |
| case RPM_SUSPENDING: |
| return rq->rq_flags & RQF_PM; |
| case RPM_SUSPENDED: |
| return false; |
| default: |
| return true; |
| } |
| } |
| #else |
| static bool blk_pm_allow_request(struct request *rq) |
| { |
| return true; |
| } |
| #endif |
| |
| void blk_account_io_start(struct request *rq, bool new_io) |
| { |
| struct hd_struct *part; |
| int rw = rq_data_dir(rq); |
| int cpu; |
| |
| if (!blk_do_io_stat(rq)) |
| return; |
| |
| cpu = part_stat_lock(); |
| |
| if (!new_io) { |
| part = rq->part; |
| part_stat_inc(cpu, 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_round_stats(rq->q, cpu, part); |
| part_inc_in_flight(rq->q, part, rw); |
| rq->part = part; |
| } |
| |
| part_stat_unlock(); |
| } |
| |
| static struct request *elv_next_request(struct request_queue *q) |
| { |
| struct request *rq; |
| struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); |
| |
| WARN_ON_ONCE(q->mq_ops); |
| |
| while (1) { |
| list_for_each_entry(rq, &q->queue_head, queuelist) { |
| if (blk_pm_allow_request(rq)) |
| return rq; |
| |
| if (rq->rq_flags & RQF_SOFTBARRIER) |
| break; |
| } |
| |
| /* |
| * Flush request is running and flush request isn't queueable |
| * in the drive, we can hold the queue till flush request is |
| * finished. Even we don't do this, driver can't dispatch next |
| * requests and will requeue them. And this can improve |
| * throughput too. For example, we have request flush1, write1, |
| * flush 2. flush1 is dispatched, then queue is hold, write1 |
| * isn't inserted to queue. After flush1 is finished, flush2 |
| * will be dispatched. Since disk cache is already clean, |
| * flush2 will be finished very soon, so looks like flush2 is |
| * folded to flush1. |
| * Since the queue is hold, a flag is set to indicate the queue |
| * should be restarted later. Please see flush_end_io() for |
| * details. |
| */ |
| if (fq->flush_pending_idx != fq->flush_running_idx && |
| !queue_flush_queueable(q)) { |
| fq->flush_queue_delayed = 1; |
| return NULL; |
| } |
| if (unlikely(blk_queue_bypass(q)) || |
| !q->elevator->type->ops.sq.elevator_dispatch_fn(q, 0)) |
| return NULL; |
| } |
| } |
| |
| /** |
| * blk_peek_request - peek at the top of a request queue |
| * @q: request queue to peek at |
| * |
| * Description: |
| * Return the request at the top of @q. The returned request |
| * should be started using blk_start_request() before LLD starts |
| * processing it. |
| * |
| * Return: |
| * Pointer to the request at the top of @q if available. Null |
| * otherwise. |
| */ |
| struct request *blk_peek_request(struct request_queue *q) |
| { |
| struct request *rq; |
| int ret; |
| |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| while ((rq = elv_next_request(q)) != NULL) { |
| if (!(rq->rq_flags & RQF_STARTED)) { |
| /* |
| * This is the first time the device driver |
| * sees this request (possibly after |
| * requeueing). Notify IO scheduler. |
| */ |
| if (rq->rq_flags & RQF_SORTED) |
| elv_activate_rq(q, rq); |
| |
| /* |
| * just mark as started even if we don't start |
| * it, a request that has been delayed should |
| * not be passed by new incoming requests |
| */ |
| rq->rq_flags |= RQF_STARTED; |
| trace_block_rq_issue(q, rq); |
| } |
| |
| if (!q->boundary_rq || q->boundary_rq == rq) { |
| q->end_sector = rq_end_sector(rq); |
| q->boundary_rq = NULL; |
| } |
| |
| if (rq->rq_flags & RQF_DONTPREP) |
| break; |
| |
| if (q->dma_drain_size && blk_rq_bytes(rq)) { |
| /* |
| * make sure space for the drain appears we |
| * know we can do this because max_hw_segments |
| * has been adjusted to be one fewer than the |
| * device can handle |
| */ |
| rq->nr_phys_segments++; |
| } |
| |
| if (!q->prep_rq_fn) |
| break; |
| |
| ret = q->prep_rq_fn(q, rq); |
| if (ret == BLKPREP_OK) { |
| break; |
| } else if (ret == BLKPREP_DEFER) { |
| /* |
| * the request may have been (partially) prepped. |
| * we need to keep this request in the front to |
| * avoid resource deadlock. RQF_STARTED will |
| * prevent other fs requests from passing this one. |
| */ |
| if (q->dma_drain_size && blk_rq_bytes(rq) && |
| !(rq->rq_flags & RQF_DONTPREP)) { |
| /* |
| * remove the space for the drain we added |
| * so that we don't add it again |
| */ |
| --rq->nr_phys_segments; |
| } |
| |
| rq = NULL; |
| break; |
| } else if (ret == BLKPREP_KILL || ret == BLKPREP_INVALID) { |
| rq->rq_flags |= RQF_QUIET; |
| /* |
| * Mark this request as started so we don't trigger |
| * any debug logic in the end I/O path. |
| */ |
| blk_start_request(rq); |
| __blk_end_request_all(rq, ret == BLKPREP_INVALID ? |
| BLK_STS_TARGET : BLK_STS_IOERR); |
| } else { |
| printk(KERN_ERR "%s: bad return=%d\n", __func__, ret); |
| break; |
| } |
| } |
| |
| return rq; |
| } |
| EXPORT_SYMBOL(blk_peek_request); |
| |
| static void blk_dequeue_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| BUG_ON(list_empty(&rq->queuelist)); |
| BUG_ON(ELV_ON_HASH(rq)); |
| |
| list_del_init(&rq->queuelist); |
| |
| /* |
| * the time frame between a request being removed from the lists |
| * and to it is freed is accounted as io that is in progress at |
| * the driver side. |
| */ |
| if (blk_account_rq(rq)) |
| q->in_flight[rq_is_sync(rq)]++; |
| } |
| |
| /** |
| * blk_start_request - start request processing on the driver |
| * @req: request to dequeue |
| * |
| * Description: |
| * Dequeue @req and start timeout timer on it. This hands off the |
| * request to the driver. |
| */ |
| void blk_start_request(struct request *req) |
| { |
| lockdep_assert_held(req->q->queue_lock); |
| WARN_ON_ONCE(req->q->mq_ops); |
| |
| blk_dequeue_request(req); |
| |
| if (test_bit(QUEUE_FLAG_STATS, &req->q->queue_flags)) { |
| req->io_start_time_ns = ktime_get_ns(); |
| #ifdef CONFIG_BLK_DEV_THROTTLING_LOW |
| req->throtl_size = blk_rq_sectors(req); |
| #endif |
| req->rq_flags |= RQF_STATS; |
| rq_qos_issue(req->q, req); |
| } |
| |
| BUG_ON(blk_rq_is_complete(req)); |
| blk_add_timer(req); |
| } |
| EXPORT_SYMBOL(blk_start_request); |
| |
| /** |
| * blk_fetch_request - fetch a request from a request queue |
| * @q: request queue to fetch a request from |
| * |
| * Description: |
| * Return the request at the top of @q. The request is started on |
| * return and LLD can start processing it immediately. |
| * |
| * Return: |
| * Pointer to the request at the top of @q if available. Null |
| * otherwise. |
| */ |
| struct request *blk_fetch_request(struct request_queue *q) |
| { |
| struct request *rq; |
| |
| lockdep_assert_held(q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| rq = blk_peek_request(q); |
| if (rq) |
| blk_start_request(rq); |
| return rq; |
| } |
| EXPORT_SYMBOL(blk_fetch_request); |
| |
| /* |
| * 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_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; |
| |
| if (unlikely(error && !blk_rq_is_passthrough(req) && |
| !(req->rq_flags & RQF_QUIET))) |
| print_req_error(req, error); |
| |
| 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 */ |
| blk_recalc_rq_segments(req); |
| } |
| |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(blk_update_request); |
| |
| static bool blk_update_bidi_request(struct request *rq, blk_status_t error, |
| unsigned int nr_bytes, |
| unsigned int bidi_bytes) |
| { |
| if (blk_update_request(rq, error, nr_bytes)) |
| return true; |
| |
| /* Bidi request must be completed as a whole */ |
| if (unlikely(blk_bidi_rq(rq)) && |
| blk_update_request(rq->next_rq, error, bidi_bytes)) |
| return true; |
| |
| if (blk_queue_add_random(rq->q)) |
| add_disk_randomness(rq->rq_disk); |
| |
| return false; |
| } |
| |
| /** |
| * blk_unprep_request - unprepare a request |
| * @req: the request |
| * |
| * This function makes a request ready for complete resubmission (or |
| * completion). It happens only after all error handling is complete, |
| * so represents the appropriate moment to deallocate any resources |
| * that were allocated to the request in the prep_rq_fn. The queue |
| * lock is held when calling this. |
| */ |
| void blk_unprep_request(struct request *req) |
| { |
| struct request_queue *q = req->q; |
| |
| req->rq_flags &= ~RQF_DONTPREP; |
| if (q->unprep_rq_fn) |
| q->unprep_rq_fn(q, req); |
| } |
| EXPORT_SYMBOL_GPL(blk_unprep_request); |
| |
| void blk_finish_request(struct request *req, blk_status_t error) |
| { |
| struct request_queue *q = req->q; |
| u64 now = ktime_get_ns(); |
| |
| lockdep_assert_held(req->q->queue_lock); |
| WARN_ON_ONCE(q->mq_ops); |
| |
| if (req->rq_flags & RQF_STATS) |
| blk_stat_add(req, now); |
| |
| if (req->rq_flags & RQF_QUEUED) |
| blk_queue_end_tag(q, req); |
| |
| BUG_ON(blk_queued_rq(req)); |
| |
| if (unlikely(laptop_mode) && !blk_rq_is_passthrough(req)) |
| laptop_io_completion(req->q->backing_dev_info); |
| |
| blk_delete_timer(req); |
| |
| if (req->rq_flags & RQF_DONTPREP) |
| blk_unprep_request(req); |
| |
| blk_account_io_done(req, now); |
| |
| if (req->end_io) { |
| rq_qos_done(q, req); |
| req->end_io(req, error); |
| } else { |
| if (blk_bidi_rq(req)) |
| __blk_put_request(req->next_rq->q, req->next_rq); |
| |
| __blk_put_request(q, req); |
| } |
| } |
| EXPORT_SYMBOL(blk_finish_request); |
| |
| /** |
| * blk_end_bidi_request - Complete a bidi request |
| * @rq: the request to complete |
| * @error: block status code |
| * @nr_bytes: number of bytes to complete @rq |
| * @bidi_bytes: number of bytes to complete @rq->next_rq |
| * |
| * Description: |
| * Ends I/O on a number of bytes attached to @rq and @rq->next_rq. |
| * Drivers that supports bidi can safely call this member for any |
| * type of request, bidi or uni. In the later case @bidi_bytes is |
| * just ignored. |
| * |
| * Return: |
| * %false - we are done with this request |
| * %true - still buffers pending for this request |
| **/ |
| static bool blk_end_bidi_request(struct request *rq, blk_status_t error, |
| unsigned int nr_bytes, unsigned int bidi_bytes) |
| { |
| struct request_queue *q = rq->q; |
| unsigned long flags; |
| |
| WARN_ON_ONCE(q->mq_ops); |
| |
| if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
| return true; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| blk_finish_request(rq, error); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| return false; |
| } |
| |
| /** |
| * __blk_end_bidi_request - Complete a bidi request with queue lock held |
| * @rq: the request to complete |
| * @error: block status code |
| * @nr_bytes: number of bytes to complete @rq |
| * @bidi_bytes: number of bytes to complete @rq->next_rq |
| * |
| * Description: |
| * Identical to blk_end_bidi_request() except that queue lock is |
| * assumed to be locked on entry and remains so on return. |
| * |
| * Return: |
| * %false - we are done with this request |
| * %true - still buffers pending for this request |
| **/ |
| static bool __blk_end_bidi_request(struct request *rq, blk_status_t error, |
| unsigned int nr_bytes, unsigned int bidi_bytes) |
| { |
| lockdep_assert_held(rq->q->queue_lock); |
| WARN_ON_ONCE(rq->q->mq_ops); |
| |
| if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) |
| return true; |
| |
| blk_finish_request(rq, error); |
| |
| return false; |
| } |
| |