| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Jens Axboe | 4362 | 32.70% | 110 | 21.36% |
| Tejun Heo | 2013 | 15.09% | 75 | 14.56% |
| Christoph Hellwig | 1880 | 14.09% | 46 | 8.93% |
| Bart Van Assche | 1352 | 10.13% | 37 | 7.18% |
| Neil Brown | 424 | 3.18% | 12 | 2.33% |
| Kiyoshi Ueda | 338 | 2.53% | 10 | 1.94% |
| Mike Snitzer | 291 | 2.18% | 9 | 1.75% |
| Dan J Williams | 186 | 1.39% | 2 | 0.39% |
| FUJITA Tomonori | 178 | 1.33% | 3 | 0.58% |
| Shaohua Li | 157 | 1.18% | 13 | 2.52% |
| Ming Lei | 152 | 1.14% | 14 | 2.72% |
| Andrew Morton | 146 | 1.09% | 16 | 3.11% |
| Jeff Moyer | 140 | 1.05% | 4 | 0.78% |
| Ilya Dryomov | 108 | 0.81% | 2 | 0.39% |
| Michael Christie | 101 | 0.76% | 10 | 1.94% |
| Kent Overstreet | 97 | 0.73% | 7 | 1.36% |
| James Bottomley | 92 | 0.69% | 4 | 0.78% |
| Akinobu Mita | 85 | 0.64% | 4 | 0.78% |
| Linus Torvalds (pre-git) | 84 | 0.63% | 19 | 3.69% |
| Goldwyn Rodrigues | 76 | 0.57% | 1 | 0.19% |
| Linus Torvalds | 74 | 0.55% | 13 | 2.52% |
| Asias He | 69 | 0.52% | 2 | 0.39% |
| Omar Sandoval | 68 | 0.51% | 5 | 0.97% |
| Jerome Marchand | 56 | 0.42% | 4 | 0.78% |
| Ilya Loginov | 53 | 0.40% | 1 | 0.19% |
| Martin K. Petersen | 50 | 0.37% | 6 | 1.17% |
| David Rientjes | 48 | 0.36% | 1 | 0.19% |
| Howard McLauchlan | 48 | 0.36% | 1 | 0.19% |
| Lei Ming | 42 | 0.31% | 5 | 0.97% |
| Joe Lawrence | 33 | 0.25% | 1 | 0.19% |
| Jan Kara | 30 | 0.22% | 2 | 0.39% |
| Keith Busch | 29 | 0.22% | 2 | 0.39% |
| Mikulas Patocka | 27 | 0.20% | 2 | 0.39% |
| Arnaldo Carvalho de Melo | 24 | 0.18% | 2 | 0.39% |
| Jianpeng Ma | 23 | 0.17% | 2 | 0.39% |
| Divyesh Shah | 23 | 0.17% | 2 | 0.39% |
| Martin Dalecki | 21 | 0.16% | 2 | 0.39% |
| Hannes Reinecke | 20 | 0.15% | 3 | 0.58% |
| Al Viro | 19 | 0.14% | 2 | 0.39% |
| Matthew Garrett | 18 | 0.13% | 1 | 0.19% |
| Boaz Harrosh | 18 | 0.13% | 2 | 0.39% |
| Michael Callahan | 17 | 0.13% | 1 | 0.19% |
| Nicholas Piggin | 17 | 0.13% | 3 | 0.58% |
| Kees Cook | 16 | 0.12% | 1 | 0.19% |
| Tahsin Erdogan | 14 | 0.10% | 1 | 0.19% |
| Nikanth Karthikesan | 13 | 0.10% | 2 | 0.39% |
| Waiman Long | 13 | 0.10% | 1 | 0.19% |
| Dave Jones | 12 | 0.09% | 1 | 0.19% |
| Josef Bacik | 12 | 0.09% | 2 | 0.39% |
| Shaun Tancheff | 12 | 0.09% | 1 | 0.19% |
| Chaitanya Kulkarni | 12 | 0.09% | 1 | 0.19% |
| Vivek Goyal | 12 | 0.09% | 2 | 0.39% |
| Adam Manzanares | 10 | 0.07% | 1 | 0.19% |
| Jun'ichi Nomura | 9 | 0.07% | 2 | 0.39% |
| David Woodhouse | 9 | 0.07% | 1 | 0.19% |
| Keith Mannthey | 9 | 0.07% | 1 | 0.19% |
| Robert Elliott | 8 | 0.06% | 2 | 0.39% |
| Lin Ming | 8 | 0.06% | 2 | 0.39% |
| MinChan Kim | 7 | 0.05% | 1 | 0.19% |
| Peter Zijlstra | 7 | 0.05% | 1 | 0.19% |
| Darrick J. Wong | 7 | 0.05% | 1 | 0.19% |
| xiao jin | 6 | 0.04% | 1 | 0.19% |
| Christoph Lameter | 6 | 0.04% | 2 | 0.39% |
| Li Zefan | 5 | 0.04% | 1 | 0.19% |
| Mike Anderson | 5 | 0.04% | 1 | 0.19% |
| Ingo Molnar | 5 | 0.04% | 1 | 0.19% |
| Adrian Hunter | 4 | 0.03% | 1 | 0.19% |
| San Mehat | 3 | 0.02% | 1 | 0.19% |
| Jianchao Wang | 2 | 0.01% | 1 | 0.19% |
| Jiufei (Joyce) Xue | 2 | 0.01% | 1 | 0.19% |
| Maninder Singh | 2 | 0.01% | 1 | 0.19% |
| Damien Le Moal | 2 | 0.01% | 1 | 0.19% |
| Ezequiel García | 2 | 0.01% | 1 | 0.19% |
| Thomas Gleixner | 2 | 0.01% | 1 | 0.19% |
| Roman Peniaev | 2 | 0.01% | 1 | 0.19% |
| Randy Dunlap | 2 | 0.01% | 2 | 0.39% |
| Greg Kroah-Hartman | 1 | 0.01% | 1 | 0.19% |
| Masanari Iida | 1 | 0.01% | 1 | 0.19% |
| Suresh Jayaraman | 1 | 0.01% | 1 | 0.19% |
| Nicolai Stange | 1 | 0.01% | 1 | 0.19% |
| Adrian Bunk | 1 | 0.01% | 1 | 0.19% |
| Alan Jenkins | 1 | 0.01% | 1 | 0.19% |
| Duan Jiong | 1 | 0.01% | 1 | 0.19% |
| Brian King | 1 | 0.01% | 1 | 0.19% |
| Dan Carpenter | 1 | 0.01% | 1 | 0.19% |
| Dmitriy Monakhov | 1 | 0.01% | 1 | 0.19% |
| Kirill A. Shutemov | 1 | 0.01% | 1 | 0.19% |
| Total | 13340 | 515 |
/* * 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-pm.h" #include "blk-rq-qos.h" #ifdef CONFIG_DEBUG_FS struct dentry *blk_debugfs_root; #endif EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete); EXPORT_TRACEPOINT_SYMBOL_GPL(block_split); EXPORT_TRACEPOINT_SYMBOL_GPL(block_unplug); DEFINE_IDA(blk_queue_ida); /* * For 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; } 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; cancel_delayed_work_sync(&q->requeue_work); 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_free_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_pm_request_resume(q), !blk_queue_pm_only(q)))) || blk_queue_dying(q)); if (blk_queue_dying(q)) return -ENODEV; } } void blk_queue_exit(struct request_queue *q) { percpu_ref_put(&q->q_usage_counter); } static void blk_queue_usage_counter_release(struct percpu_ref *ref) { struct request_queue *q = container_of(ref, struct request_queue, q_usage_counter); wake_up_all(&q->mq_freeze_wq); } static void blk_rq_timed_out_timer(struct timer_list *t) { struct request_queue *q = from_timer(q, t, timeout); kblockd_schedule_work(&q->timeout_work); } /** * 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, NULL); 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); 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); 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); blk_pm_mark_last_busy(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_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; q = NULL; } } 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); } 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(); } } 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) { #ifdef CONFIG_PM /* * If a request gets queued in state RPM_SUSPENDED * then that's a kernel bug. */ WARN_ON_ONCE(q->rpm_status == RPM_SUSPENDED); #endif return rq; } /* * 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; } /** * blk_end_request - Helper function for drivers to complete the request. * @rq: the request being processed * @error: block status code * @nr_bytes: number of bytes to complete * * Description: * Ends I/O on a number of bytes attached to @rq. * If @rq has leftover, sets it up for the next range of segments. * * Return: * %false - we are done with this request * %true - still buffers pending for this request **/ bool blk_end_request(struct request *rq, blk_status_t error, unsigned int nr_bytes) { WARN_ON_ONCE(rq->q->mq_ops); return blk_end_bidi_request(rq, error, nr_bytes, 0); } EXPORT_SYMBOL(blk_end_request); /** * blk_end_request_all - Helper function for drives to finish the request. * @rq: the request to finish * @error: block status code * * Description: * Completely finish @rq. */ void blk_end_request_all(struct request *rq, blk_status_t error) { bool pending; unsigned int bidi_bytes = 0; if (unlikely(blk_bidi_rq(rq))) bidi_bytes = blk_rq_bytes(rq->next_rq); pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); BUG_ON(pending); } EXPORT_SYMBOL(blk_end_request_all); /** * __blk_end_request - Helper function for drivers to complete the request. * @rq: the request being processed * @error: block status code * @nr_bytes: number of bytes to complete * * Description: * Must be called with queue lock held unlike blk_end_request(). * * Return: * %false - we are done with this request * %true - still buffers pending for this request **/ bool __blk_end_request(struct request *rq, blk_status_t error, unsigned int nr_bytes) { lockdep_assert_held(rq->q->queue_lock); WARN_ON_ONCE(rq->q->mq_ops); return __blk_end_bidi_request(rq, error, nr_bytes, 0); } EXPORT_SYMBOL(__blk_end_request); /** * __blk_end_request_all - Helper function for drives to finish the request. * @rq: the request to finish * @error: block status code * * Description: * Completely finish @rq. Must be called with queue lock held. */ void __blk_end_request_all(struct request *rq, blk_status_t error) { bool pending; unsigned int bidi_bytes = 0; lockdep_assert_held(rq->q->queue_lock); WARN_ON_ONCE(rq->q->mq_ops); if (unlikely(blk_bidi_rq(rq))) bidi_bytes = blk_rq_bytes(rq->next_rq); pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes); BUG_ON(pending); } EXPORT_SYMBOL(__blk_end_request_all); /** * __blk_end_request_cur - Helper function to finish the current request chunk. * @rq: the request to finish the current chunk for * @error: block status code * * Description: * Complete the current consecutively mapped chunk from @rq. Must * be called with queue lock held. * * Return: * %false - we are done with this request * %true - still buffers pending for this request */ bool __blk_end_request_cur(struct request *rq, blk_status_t error) { return __blk_end_request(rq, error, blk_rq_cur_bytes(rq)); } EXPORT_SYMBOL(__blk_end_request_cur); void blk_rq_bio_prep(struct request_queue *q, struct request *rq, struct bio *bio) { if (bio_has_data(bio)) rq->nr_phys_segments = bio_phys_segments(q, bio); else if (bio_op(bio) == REQ_OP_DISCARD) rq->nr_phys_segments = 1; rq->__data_len = bio->bi_iter.bi_size; rq->bio = rq->biotail = bio; if (bio->bi_disk) rq->rq_disk = bio->bi_disk; } #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE /** * rq_flush_dcache_pages - Helper function to flush all pages in a request * @rq: the request to be flushed * * Description: * Flush all pages in @rq. */ void rq_flush_dcache_pages(struct request *rq) { struct req_iterator iter; struct bio_vec bvec; rq_for_each_segment(bvec, rq, iter) flush_dcache_page(bvec.bv_page); } EXPORT_SYMBOL_GPL(rq_flush_dcache_pages); #endif /** * blk_lld_busy - Check if underlying low-level drivers of a device are busy * @q : the queue of the device being checked * * Description: * Check if underlying low-level drivers of a device are busy. * If the drivers want to export their busy state, they must set own * exporting function using blk_queue_lld_busy() first. * * Basically, this function is used only by request stacking drivers * to stop dispatching requests to underlying devices when underlying * devices are busy. This behavior helps more I/O merging on the queue * of the request stacking driver and prevents I/O throughput regression * on burst I/O load. * * Return: * 0 - Not busy (The request stacking driver should dispatch request) * 1 - Busy (The request stacking driver should stop dispatching request) */ int blk_lld_busy(struct request_queue *q) { if (q->lld_busy_fn) return q->lld_busy_fn(q); return 0; } EXPORT_SYMBOL_GPL(blk_lld_busy); /** * blk_rq_unprep_clone - Helper function to free all bios in a cloned request * @rq: the clone request to be cleaned up * * Description: * Free all bios in @rq for a cloned request. */ void blk_rq_unprep_clone(struct request *rq) { struct bio *bio; while ((bio = rq->bio) != NULL) { rq->bio = bio->bi_next; bio_put(bio); } } EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); /* * Copy attributes of the original request to the clone request. * The actual data parts (e.g. ->cmd, ->sense) are not copied. */ static void __blk_rq_prep_clone(struct request *dst, struct request *src) { dst->cpu = src->cpu; dst->__sector = blk_rq_pos(src); dst->__data_len = blk_rq_bytes(src); if (src->rq_flags & RQF_SPECIAL_PAYLOAD) { dst->rq_flags |= RQF_SPECIAL_PAYLOAD; dst->special_vec = src->special_vec; } dst->nr_phys_segments = src->nr_phys_segments; dst->ioprio = src->ioprio; dst->extra_len = src->extra_len; } /** * blk_rq_prep_clone - Helper function to setup clone request * @rq: the request to be setup * @rq_src: original request to be cloned * @bs: bio_set that bios for clone are allocated from * @gfp_mask: memory allocation mask for bio * @bio_ctr: setup function to be called for each clone bio. * Returns %0 for success, non %0 for failure. * @data: private data to be passed to @bio_ctr * * Description: * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. * The actual data parts of @rq_src (e.g. ->cmd, ->sense) * are not copied, and copying such parts is the caller's responsibility. * Also, pages which the original bios are pointing to are not copied * and the cloned bios just point same pages. * So cloned bios must be completed before original bios, which means * the caller must complete @rq before @rq_src. */ int blk_rq_prep_clone(struct request *rq, struct request *rq_src, struct bio_set *bs, gfp_t gfp_mask, int (*bio_ctr)(struct bio *, struct bio *, void *), void *data) { struct bio *bio, *bio_src; if (!bs) bs = &fs_bio_set; __rq_for_each_bio(bio_src, rq_src) { bio = bio_clone_fast(bio_src, gfp_mask, bs); if (!bio) goto free_and_out; if (bio_ctr && bio_ctr(bio, bio_src, data)) goto free_and_out; if (rq->bio) { rq->biotail->bi_next = bio; rq->biotail = bio; } else rq->bio = rq->biotail = bio; } __blk_rq_prep_clone(rq, rq_src); return 0; free_and_out: if (bio) bio_put(bio); blk_rq_unprep_clone(rq); return -ENOMEM; } EXPORT_SYMBOL_GPL(blk_rq_prep_clone); int kblockd_schedule_work(struct work_struct *work) { return queue_work(kblockd_workqueue, work); } EXPORT_SYMBOL(kblockd_schedule_work); int kblockd_schedule_work_on(int cpu, struct work_struct *work) { return queue_work_on(cpu, kblockd_workqueue, work); } EXPORT_SYMBOL(kblockd_schedule_work_on); int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay) { return mod_delayed_work_on(cpu, kblockd_workqueue, dwork, delay); } EXPORT_SYMBOL(kblockd_mod_delayed_work_on); /** * blk_start_plug - initialize blk_plug and track it inside the task_struct * @plug: The &struct blk_plug that needs to be initialized * * Description: * Tracking blk_plug inside the task_struct will help with auto-flushing the * pending I/O should the task end up blocking between blk_start_plug() and * blk_finish_plug(). This is important from a performance perspective, but * also ensures that we don't deadlock. For instance, if the task is blocking * for a memory allocation, memory reclaim could end up wanting to free a * page belonging to that request that is currently residing in our private * plug. By flushing the pending I/O when the process goes to sleep, we avoid * this kind of deadlock. */ void blk_start_plug(struct blk_plug *plug) { struct task_struct *tsk = current; /* * If this is a nested plug, don't actually assign it. */ if (tsk->plug) return; INIT_LIST_HEAD(&plug->list); INIT_LIST_HEAD(&plug->mq_list); INIT_LIST_HEAD(&plug->cb_list); /* * Store ordering should not be needed here, since a potential * preempt will imply a full memory barrier */ tsk->plug = plug; } EXPORT_SYMBOL(blk_start_plug); static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) { struct request *rqa = container_of(a, struct request, queuelist); struct request *rqb = container_of(b, struct request, queuelist); return !(rqa->q < rqb->q || (rqa->q == rqb->q && blk_rq_pos(rqa) < blk_rq_pos(rqb))); } /* * If 'from_schedule' is true, then postpone the dispatch of requests * until a safe kblockd context. We due this to avoid accidental big * additional stack usage in driver dispatch, in places where the originally * plugger did not intend it. */ static void queue_unplugged(struct request_queue *q, unsigned int depth, bool from_schedule) __releases(q->queue_lock) { lockdep_assert_held(q->queue_lock); trace_block_unplug(q, depth, !from_schedule); if (from_schedule) blk_run_queue_async(q); else __blk_run_queue(q); spin_unlock_irq(q->queue_lock); } static void flush_plug_callbacks(struct blk_plug *plug, bool from_schedule) { LIST_HEAD(callbacks); while (!list_empty(&plug->cb_list)) { list_splice_init(&plug->cb_list, &callbacks); while (!list_empty(&callbacks)) { struct blk_plug_cb *cb = list_first_entry(&callbacks, struct blk_plug_cb, list); list_del(&cb->list); cb->callback(cb, from_schedule); } } } struct blk_plug_cb *blk_check_plugged(blk_plug_cb_fn unplug, void *data, int size) { struct blk_plug *plug = current->plug; struct blk_plug_cb *cb; if (!plug) return NULL; list_for_each_entry(cb, &plug->cb_list, list) if (cb->callback == unplug && cb->data == data) return cb; /* Not currently on the callback list */ BUG_ON(size < sizeof(*cb)); cb = kzalloc(size, GFP_ATOMIC); if (cb) { cb->data = data; cb->callback = unplug; list_add(&cb->list, &plug->cb_list); } return cb; } EXPORT_SYMBOL(blk_check_plugged); void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) { struct request_queue *q; struct request *rq; LIST_HEAD(list); unsigned int depth; flush_plug_callbacks(plug, from_schedule); if (!list_empty(&plug->mq_list)) blk_mq_flush_plug_list(plug, from_schedule); if (list_empty(&plug->list)) return; list_splice_init(&plug->list, &list); list_sort(NULL, &list, plug_rq_cmp); q = NULL; depth = 0; while (!list_empty(&list)) { rq = list_entry_rq(list.next); list_del_init(&rq->queuelist); BUG_ON(!rq->q); if (rq->q != q) { /* * This drops the queue lock */ if (q) queue_unplugged(q, depth, from_schedule); q = rq->q; depth = 0; spin_lock_irq(q->queue_lock); } /* * Short-circuit if @q is dead */ if (unlikely(blk_queue_dying(q))) { __blk_end_request_all(rq, BLK_STS_IOERR); continue; } /* * rq is already accounted, so use raw insert */ if (op_is_flush(rq->cmd_flags)) __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); else __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); depth++; } /* * This drops the queue lock */ if (q) queue_unplugged(q, depth, from_schedule); } void blk_finish_plug(struct blk_plug *plug) { if (plug != current->plug) return; blk_flush_plug_list(plug, false); current->plug = NULL; } EXPORT_SYMBOL(blk_finish_plug); int __init blk_dev_init(void) { BUILD_BUG_ON(REQ_OP_LAST >= (1 << REQ_OP_BITS)); BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * FIELD_SIZEOF(struct request, cmd_flags)); BUILD_BUG_ON(REQ_OP_BITS + REQ_FLAG_BITS > 8 * FIELD_SIZEOF(struct bio, bi_opf)); /* used for unplugging and affects IO latency/throughput - HIGHPRI */ kblockd_workqueue = alloc_workqueue("kblockd", WQ_MEM_RECLAIM | WQ_HIGHPRI, 0); if (!kblockd_workqueue) panic("Failed to create kblockd\n"); request_cachep = kmem_cache_create("blkdev_requests", sizeof(struct request), 0, SLAB_PANIC, NULL); blk_requestq_cachep = kmem_cache_create("request_queue", sizeof(struct request_queue), 0, SLAB_PANIC, NULL); #ifdef CONFIG_DEBUG_FS blk_debugfs_root = debugfs_create_dir("block", NULL); #endif return 0; }
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