| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Jens Axboe | 5881 | 40.14% | 124 | 27.93% |
| Christoph Hellwig | 2083 | 14.22% | 66 | 14.86% |
| Ming Lei | 2041 | 13.93% | 61 | 13.74% |
| Bart Van Assche | 889 | 6.07% | 37 | 8.33% |
| Jianchao Wang | 663 | 4.52% | 13 | 2.93% |
| Omar Sandoval | 642 | 4.38% | 16 | 3.60% |
| Keith Busch | 595 | 4.06% | 14 | 3.15% |
| Tejun Heo | 226 | 1.54% | 12 | 2.70% |
| Mike Snitzer | 203 | 1.39% | 4 | 0.90% |
| Lei Ming | 154 | 1.05% | 11 | 2.48% |
| Shaohua Li | 147 | 1.00% | 6 | 1.35% |
| Ming Lin | 131 | 0.89% | 2 | 0.45% |
| Jeff Moyer | 127 | 0.87% | 2 | 0.45% |
| Pavel Begunkov | 124 | 0.85% | 4 | 0.90% |
| Stephen Bates | 102 | 0.70% | 1 | 0.23% |
| Thomas Gleixner | 60 | 0.41% | 3 | 0.68% |
| Johannes Thumshirn | 59 | 0.40% | 2 | 0.45% |
| Bob Liu | 46 | 0.31% | 1 | 0.23% |
| Yufen Yu | 37 | 0.25% | 5 | 1.13% |
| Max Gurtovoy | 33 | 0.23% | 1 | 0.23% |
| Catalin Marinas | 25 | 0.17% | 1 | 0.23% |
| Goldwyn Rodrigues | 24 | 0.16% | 1 | 0.23% |
| Dan J Williams | 22 | 0.15% | 1 | 0.23% |
| Sagi Grimberg | 21 | 0.14% | 1 | 0.23% |
| Paolo Bonzini | 20 | 0.14% | 2 | 0.45% |
| Joe Lawrence | 20 | 0.14% | 1 | 0.23% |
| Robert Elliott | 18 | 0.12% | 2 | 0.45% |
| Hou Tao | 16 | 0.11% | 2 | 0.45% |
| Jes Sorensen | 16 | 0.11% | 1 | 0.23% |
| André Almeida | 16 | 0.11% | 2 | 0.45% |
| Peter Zijlstra | 14 | 0.10% | 1 | 0.23% |
| Josef Bacik | 13 | 0.09% | 2 | 0.45% |
| Dongli Zhang | 13 | 0.09% | 2 | 0.45% |
| Damien Le Moal | 13 | 0.09% | 2 | 0.45% |
| Aleksei Zakharov | 11 | 0.08% | 1 | 0.23% |
| Hannes Reinecke | 11 | 0.08% | 1 | 0.23% |
| Xiaoguang Wang | 11 | 0.08% | 1 | 0.23% |
| Wei Fang | 9 | 0.06% | 1 | 0.23% |
| Mikulas Patocka | 9 | 0.06% | 1 | 0.23% |
| John Garry | 8 | 0.05% | 2 | 0.45% |
| Gabriel Krisman Bertazi | 8 | 0.05% | 2 | 0.45% |
| Roman Peniaev | 8 | 0.05% | 1 | 0.23% |
| Ingo Molnar | 8 | 0.05% | 4 | 0.90% |
| Nicholas Bellinger | 7 | 0.05% | 1 | 0.23% |
| Wendy Xiong | 7 | 0.05% | 1 | 0.23% |
| huhai | 7 | 0.05% | 2 | 0.45% |
| Kees Cook | 7 | 0.05% | 1 | 0.23% |
| zhengbin | 6 | 0.04% | 1 | 0.23% |
| Akinobu Mita | 6 | 0.04% | 2 | 0.45% |
| Chong Yuan | 5 | 0.03% | 1 | 0.23% |
| Nitesh Shetty | 5 | 0.03% | 1 | 0.23% |
| Dan Carpenter | 4 | 0.03% | 1 | 0.23% |
| Michael Christie | 4 | 0.03% | 2 | 0.45% |
| Raghavendra K T | 3 | 0.02% | 1 | 0.23% |
| Dave Hansen | 3 | 0.02% | 1 | 0.23% |
| Minwoo Im | 3 | 0.02% | 2 | 0.45% |
| Bartlomiej Zolnierkiewicz | 2 | 0.01% | 1 | 0.23% |
| Linus Torvalds | 2 | 0.01% | 1 | 0.23% |
| Sebastian Andrzej Siewior | 1 | 0.01% | 1 | 0.23% |
| Raul E Rangel | 1 | 0.01% | 1 | 0.23% |
| Frédéric Weisbecker | 1 | 0.01% | 1 | 0.23% |
| Dmitriy Monakhov | 1 | 0.01% | 1 | 0.23% |
| Ilya Dryomov | 1 | 0.01% | 1 | 0.23% |
| Total | 14653 | 444 |
// SPDX-License-Identifier: GPL-2.0 /* * Block multiqueue core code * * Copyright (C) 2013-2014 Jens Axboe * Copyright (C) 2013-2014 Christoph Hellwig */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/backing-dev.h> #include <linux/bio.h> #include <linux/blkdev.h> #include <linux/kmemleak.h> #include <linux/mm.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/workqueue.h> #include <linux/smp.h> #include <linux/llist.h> #include <linux/list_sort.h> #include <linux/cpu.h> #include <linux/cache.h> #include <linux/sched/sysctl.h> #include <linux/sched/topology.h> #include <linux/sched/signal.h> #include <linux/delay.h> #include <linux/crash_dump.h> #include <linux/prefetch.h> #include <trace/events/block.h> #include <linux/blk-mq.h> #include <linux/t10-pi.h> #include "blk.h" #include "blk-mq.h" #include "blk-mq-debugfs.h" #include "blk-mq-tag.h" #include "blk-pm.h" #include "blk-stat.h" #include "blk-mq-sched.h" #include "blk-rq-qos.h" static void blk_mq_poll_stats_start(struct request_queue *q); static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb); static int blk_mq_poll_stats_bkt(const struct request *rq) { int ddir, sectors, bucket; ddir = rq_data_dir(rq); sectors = blk_rq_stats_sectors(rq); bucket = ddir + 2 * ilog2(sectors); if (bucket < 0) return -1; else if (bucket >= BLK_MQ_POLL_STATS_BKTS) return ddir + BLK_MQ_POLL_STATS_BKTS - 2; return bucket; } /* * Check if any of the ctx, dispatch list or elevator * have pending work in this hardware queue. */ static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) { return !list_empty_careful(&hctx->dispatch) || sbitmap_any_bit_set(&hctx->ctx_map) || blk_mq_sched_has_work(hctx); } /* * Mark this ctx as having pending work in this hardware queue */ static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx) { const int bit = ctx->index_hw[hctx->type]; if (!sbitmap_test_bit(&hctx->ctx_map, bit)) sbitmap_set_bit(&hctx->ctx_map, bit); } static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx) { const int bit = ctx->index_hw[hctx->type]; sbitmap_clear_bit(&hctx->ctx_map, bit); } struct mq_inflight { struct hd_struct *part; unsigned int inflight[2]; }; static bool blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx, struct request *rq, void *priv, bool reserved) { struct mq_inflight *mi = priv; if (rq->part == mi->part) mi->inflight[rq_data_dir(rq)]++; return true; } unsigned int blk_mq_in_flight(struct request_queue *q, struct hd_struct *part) { struct mq_inflight mi = { .part = part }; blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi); return mi.inflight[0] + mi.inflight[1]; } void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part, unsigned int inflight[2]) { struct mq_inflight mi = { .part = part }; blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi); inflight[0] = mi.inflight[0]; inflight[1] = mi.inflight[1]; } void blk_freeze_queue_start(struct request_queue *q) { mutex_lock(&q->mq_freeze_lock); if (++q->mq_freeze_depth == 1) { percpu_ref_kill(&q->q_usage_counter); mutex_unlock(&q->mq_freeze_lock); if (queue_is_mq(q)) blk_mq_run_hw_queues(q, false); } else { mutex_unlock(&q->mq_freeze_lock); } } EXPORT_SYMBOL_GPL(blk_freeze_queue_start); void blk_mq_freeze_queue_wait(struct request_queue *q) { wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter)); } EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait); int blk_mq_freeze_queue_wait_timeout(struct request_queue *q, unsigned long timeout) { return wait_event_timeout(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter), timeout); } EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout); /* * Guarantee no request is in use, so we can change any data structure of * the queue afterward. */ void blk_freeze_queue(struct request_queue *q) { /* * In the !blk_mq case we are only calling this to kill the * q_usage_counter, otherwise this increases the freeze depth * and waits for it to return to zero. For this reason there is * no blk_unfreeze_queue(), and blk_freeze_queue() is not * exported to drivers as the only user for unfreeze is blk_mq. */ blk_freeze_queue_start(q); blk_mq_freeze_queue_wait(q); } void blk_mq_freeze_queue(struct request_queue *q) { /* * ...just an alias to keep freeze and unfreeze actions balanced * in the blk_mq_* namespace */ blk_freeze_queue(q); } EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); void blk_mq_unfreeze_queue(struct request_queue *q) { mutex_lock(&q->mq_freeze_lock); q->mq_freeze_depth--; WARN_ON_ONCE(q->mq_freeze_depth < 0); if (!q->mq_freeze_depth) { percpu_ref_resurrect(&q->q_usage_counter); wake_up_all(&q->mq_freeze_wq); } mutex_unlock(&q->mq_freeze_lock); } EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); /* * FIXME: replace the scsi_internal_device_*block_nowait() calls in the * mpt3sas driver such that this function can be removed. */ void blk_mq_quiesce_queue_nowait(struct request_queue *q) { blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); } EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); /** * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished * @q: request queue. * * Note: this function does not prevent that the struct request end_io() * callback function is invoked. Once this function is returned, we make * sure no dispatch can happen until the queue is unquiesced via * blk_mq_unquiesce_queue(). */ void blk_mq_quiesce_queue(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; unsigned int i; bool rcu = false; blk_mq_quiesce_queue_nowait(q); queue_for_each_hw_ctx(q, hctx, i) { if (hctx->flags & BLK_MQ_F_BLOCKING) synchronize_srcu(hctx->srcu); else rcu = true; } if (rcu) synchronize_rcu(); } EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); /* * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue() * @q: request queue. * * This function recovers queue into the state before quiescing * which is done by blk_mq_quiesce_queue. */ void blk_mq_unquiesce_queue(struct request_queue *q) { blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); /* dispatch requests which are inserted during quiescing */ blk_mq_run_hw_queues(q, true); } EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); void blk_mq_wake_waiters(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; unsigned int i; queue_for_each_hw_ctx(q, hctx, i) if (blk_mq_hw_queue_mapped(hctx)) blk_mq_tag_wakeup_all(hctx->tags, true); } /* * Only need start/end time stamping if we have iostat or * blk stats enabled, or using an IO scheduler. */ static inline bool blk_mq_need_time_stamp(struct request *rq) { return (rq->rq_flags & (RQF_IO_STAT | RQF_STATS)) || rq->q->elevator; } static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, unsigned int tag, unsigned int op, u64 alloc_time_ns) { struct blk_mq_tags *tags = blk_mq_tags_from_data(data); struct request *rq = tags->static_rqs[tag]; req_flags_t rq_flags = 0; if (data->flags & BLK_MQ_REQ_INTERNAL) { rq->tag = -1; rq->internal_tag = tag; } else { if (data->hctx->flags & BLK_MQ_F_TAG_SHARED) { rq_flags = RQF_MQ_INFLIGHT; atomic_inc(&data->hctx->nr_active); } rq->tag = tag; rq->internal_tag = -1; data->hctx->tags->rqs[rq->tag] = rq; } /* csd/requeue_work/fifo_time is initialized before use */ rq->q = data->q; rq->mq_ctx = data->ctx; rq->mq_hctx = data->hctx; rq->rq_flags = rq_flags; rq->cmd_flags = op; if (data->flags & BLK_MQ_REQ_PREEMPT) rq->rq_flags |= RQF_PREEMPT; if (blk_queue_io_stat(data->q)) rq->rq_flags |= RQF_IO_STAT; INIT_LIST_HEAD(&rq->queuelist); INIT_HLIST_NODE(&rq->hash); RB_CLEAR_NODE(&rq->rb_node); rq->rq_disk = NULL; rq->part = NULL; #ifdef CONFIG_BLK_RQ_ALLOC_TIME rq->alloc_time_ns = alloc_time_ns; #endif if (blk_mq_need_time_stamp(rq)) rq->start_time_ns = ktime_get_ns(); else rq->start_time_ns = 0; rq->io_start_time_ns = 0; rq->stats_sectors = 0; rq->nr_phys_segments = 0; #if defined(CONFIG_BLK_DEV_INTEGRITY) rq->nr_integrity_segments = 0; #endif /* tag was already set */ rq->extra_len = 0; WRITE_ONCE(rq->deadline, 0); rq->timeout = 0; rq->end_io = NULL; rq->end_io_data = NULL; data->ctx->rq_dispatched[op_is_sync(op)]++; refcount_set(&rq->ref, 1); return rq; } static struct request *blk_mq_get_request(struct request_queue *q, struct bio *bio, struct blk_mq_alloc_data *data) { struct elevator_queue *e = q->elevator; struct request *rq; unsigned int tag; bool clear_ctx_on_error = false; u64 alloc_time_ns = 0; blk_queue_enter_live(q); /* alloc_time includes depth and tag waits */ if (blk_queue_rq_alloc_time(q)) alloc_time_ns = ktime_get_ns(); data->q = q; if (likely(!data->ctx)) { data->ctx = blk_mq_get_ctx(q); clear_ctx_on_error = true; } if (likely(!data->hctx)) data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx); if (data->cmd_flags & REQ_NOWAIT) data->flags |= BLK_MQ_REQ_NOWAIT; if (e) { data->flags |= BLK_MQ_REQ_INTERNAL; /* * Flush requests are special and go directly to the * dispatch list. Don't include reserved tags in the * limiting, as it isn't useful. */ if (!op_is_flush(data->cmd_flags) && e->type->ops.limit_depth && !(data->flags & BLK_MQ_REQ_RESERVED)) e->type->ops.limit_depth(data->cmd_flags, data); } else { blk_mq_tag_busy(data->hctx); } tag = blk_mq_get_tag(data); if (tag == BLK_MQ_TAG_FAIL) { if (clear_ctx_on_error) data->ctx = NULL; blk_queue_exit(q); return NULL; } rq = blk_mq_rq_ctx_init(data, tag, data->cmd_flags, alloc_time_ns); if (!op_is_flush(data->cmd_flags)) { rq->elv.icq = NULL; if (e && e->type->ops.prepare_request) { if (e->type->icq_cache) blk_mq_sched_assign_ioc(rq); e->type->ops.prepare_request(rq, bio); rq->rq_flags |= RQF_ELVPRIV; } } data->hctx->queued++; return rq; } struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op, blk_mq_req_flags_t flags) { struct blk_mq_alloc_data alloc_data = { .flags = flags, .cmd_flags = op }; struct request *rq; int ret; ret = blk_queue_enter(q, flags); if (ret) return ERR_PTR(ret); rq = blk_mq_get_request(q, NULL, &alloc_data); blk_queue_exit(q); if (!rq) return ERR_PTR(-EWOULDBLOCK); rq->__data_len = 0; rq->__sector = (sector_t) -1; rq->bio = rq->biotail = NULL; return rq; } EXPORT_SYMBOL(blk_mq_alloc_request); struct request *blk_mq_alloc_request_hctx(struct request_queue *q, unsigned int op, blk_mq_req_flags_t flags, unsigned int hctx_idx) { struct blk_mq_alloc_data alloc_data = { .flags = flags, .cmd_flags = op }; struct request *rq; unsigned int cpu; int ret; /* * If the tag allocator sleeps we could get an allocation for a * different hardware context. No need to complicate the low level * allocator for this for the rare use case of a command tied to * a specific queue. */ if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT))) return ERR_PTR(-EINVAL); if (hctx_idx >= q->nr_hw_queues) return ERR_PTR(-EIO); ret = blk_queue_enter(q, flags); if (ret) return ERR_PTR(ret); /* * Check if the hardware context is actually mapped to anything. * If not tell the caller that it should skip this queue. */ alloc_data.hctx = q->queue_hw_ctx[hctx_idx]; if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) { blk_queue_exit(q); return ERR_PTR(-EXDEV); } cpu = cpumask_first_and(alloc_data.hctx->cpumask, cpu_online_mask); alloc_data.ctx = __blk_mq_get_ctx(q, cpu); rq = blk_mq_get_request(q, NULL, &alloc_data); blk_queue_exit(q); if (!rq) return ERR_PTR(-EWOULDBLOCK); return rq; } EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx); static void __blk_mq_free_request(struct request *rq) { struct request_queue *q = rq->q; struct blk_mq_ctx *ctx = rq->mq_ctx; struct blk_mq_hw_ctx *hctx = rq->mq_hctx; const int sched_tag = rq->internal_tag; blk_pm_mark_last_busy(rq); rq->mq_hctx = NULL; if (rq->tag != -1) blk_mq_put_tag(hctx->tags, ctx, rq->tag); if (sched_tag != -1) blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag); blk_mq_sched_restart(hctx); blk_queue_exit(q); } void blk_mq_free_request(struct request *rq) { struct request_queue *q = rq->q; struct elevator_queue *e = q->elevator; struct blk_mq_ctx *ctx = rq->mq_ctx; struct blk_mq_hw_ctx *hctx = rq->mq_hctx; if (rq->rq_flags & RQF_ELVPRIV) { if (e && e->type->ops.finish_request) e->type->ops.finish_request(rq); if (rq->elv.icq) { put_io_context(rq->elv.icq->ioc); rq->elv.icq = NULL; } } ctx->rq_completed[rq_is_sync(rq)]++; if (rq->rq_flags & RQF_MQ_INFLIGHT) atomic_dec(&hctx->nr_active); if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq))) laptop_io_completion(q->backing_dev_info); rq_qos_done(q, rq); WRITE_ONCE(rq->state, MQ_RQ_IDLE); if (refcount_dec_and_test(&rq->ref)) __blk_mq_free_request(rq); } EXPORT_SYMBOL_GPL(blk_mq_free_request); inline void __blk_mq_end_request(struct request *rq, blk_status_t error) { u64 now = 0; if (blk_mq_need_time_stamp(rq)) now = ktime_get_ns(); if (rq->rq_flags & RQF_STATS) { blk_mq_poll_stats_start(rq->q); blk_stat_add(rq, now); } if (rq->internal_tag != -1) blk_mq_sched_completed_request(rq, now); blk_account_io_done(rq, now); if (rq->end_io) { rq_qos_done(rq->q, rq); rq->end_io(rq, error); } else { blk_mq_free_request(rq); } } EXPORT_SYMBOL(__blk_mq_end_request); void blk_mq_end_request(struct request *rq, blk_status_t error) { if (blk_update_request(rq, error, blk_rq_bytes(rq))) BUG(); __blk_mq_end_request(rq, error); } EXPORT_SYMBOL(blk_mq_end_request); static void __blk_mq_complete_request_remote(void *data) { struct request *rq = data; struct request_queue *q = rq->q; q->mq_ops->complete(rq); } static void __blk_mq_complete_request(struct request *rq) { struct blk_mq_ctx *ctx = rq->mq_ctx; struct request_queue *q = rq->q; bool shared = false; int cpu; WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); /* * Most of single queue controllers, there is only one irq vector * for handling IO completion, and the only irq's affinity is set * as all possible CPUs. On most of ARCHs, this affinity means the * irq is handled on one specific CPU. * * So complete IO reqeust in softirq context in case of single queue * for not degrading IO performance by irqsoff latency. */ if (q->nr_hw_queues == 1) { __blk_complete_request(rq); return; } /* * For a polled request, always complete locallly, it's pointless * to redirect the completion. */ if ((rq->cmd_flags & REQ_HIPRI) || !test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags)) { q->mq_ops->complete(rq); return; } cpu = get_cpu(); if (!test_bit(QUEUE_FLAG_SAME_FORCE, &q->queue_flags)) shared = cpus_share_cache(cpu, ctx->cpu); if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { rq->csd.func = __blk_mq_complete_request_remote; rq->csd.info = rq; rq->csd.flags = 0; smp_call_function_single_async(ctx->cpu, &rq->csd); } else { q->mq_ops->complete(rq); } put_cpu(); } static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx) __releases(hctx->srcu) { if (!(hctx->flags & BLK_MQ_F_BLOCKING)) rcu_read_unlock(); else srcu_read_unlock(hctx->srcu, srcu_idx); } static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx) __acquires(hctx->srcu) { if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { /* shut up gcc false positive */ *srcu_idx = 0; rcu_read_lock(); } else *srcu_idx = srcu_read_lock(hctx->srcu); } /** * blk_mq_complete_request - end I/O on a request * @rq: the request being processed * * Description: * Ends all I/O on a request. It does not handle partial completions. * The actual completion happens out-of-order, through a IPI handler. **/ bool blk_mq_complete_request(struct request *rq) { if (unlikely(blk_should_fake_timeout(rq->q))) return false; __blk_mq_complete_request(rq); return true; } EXPORT_SYMBOL(blk_mq_complete_request); /** * blk_mq_start_request - Start processing a request * @rq: Pointer to request to be started * * Function used by device drivers to notify the block layer that a request * is going to be processed now, so blk layer can do proper initializations * such as starting the timeout timer. */ void blk_mq_start_request(struct request *rq) { struct request_queue *q = rq->q; trace_block_rq_issue(q, rq); if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) { rq->io_start_time_ns = ktime_get_ns(); rq->stats_sectors = blk_rq_sectors(rq); rq->rq_flags |= RQF_STATS; rq_qos_issue(q, rq); } WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE); blk_add_timer(rq); WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT); 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++; } #ifdef CONFIG_BLK_DEV_INTEGRITY if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE) q->integrity.profile->prepare_fn(rq); #endif } EXPORT_SYMBOL(blk_mq_start_request); static void __blk_mq_requeue_request(struct request *rq) { struct request_queue *q = rq->q; blk_mq_put_driver_tag(rq); trace_block_rq_requeue(q, rq); rq_qos_requeue(q, rq); if (blk_mq_request_started(rq)) { WRITE_ONCE(rq->state, MQ_RQ_IDLE); rq->rq_flags &= ~RQF_TIMED_OUT; if (q->dma_drain_size && blk_rq_bytes(rq)) rq->nr_phys_segments--; } } void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list) { __blk_mq_requeue_request(rq); /* this request will be re-inserted to io scheduler queue */ blk_mq_sched_requeue_request(rq); BUG_ON(!list_empty(&rq->queuelist)); blk_mq_add_to_requeue_list(rq, true, kick_requeue_list); } EXPORT_SYMBOL(blk_mq_requeue_request); static void blk_mq_requeue_work(struct work_struct *work) { struct request_queue *q = container_of(work, struct request_queue, requeue_work.work); LIST_HEAD(rq_list); struct request *rq, *next; spin_lock_irq(&q->requeue_lock); list_splice_init(&q->requeue_list, &rq_list); spin_unlock_irq(&q->requeue_lock); list_for_each_entry_safe(rq, next, &rq_list, queuelist) { if (!(rq->rq_flags & (RQF_SOFTBARRIER | RQF_DONTPREP))) continue; rq->rq_flags &= ~RQF_SOFTBARRIER; list_del_init(&rq->queuelist); /* * If RQF_DONTPREP, rq has contained some driver specific * data, so insert it to hctx dispatch list to avoid any * merge. */ if (rq->rq_flags & RQF_DONTPREP) blk_mq_request_bypass_insert(rq, false, false); else blk_mq_sched_insert_request(rq, true, false, false); } while (!list_empty(&rq_list)) { rq = list_entry(rq_list.next, struct request, queuelist); list_del_init(&rq->queuelist); blk_mq_sched_insert_request(rq, false, false, false); } blk_mq_run_hw_queues(q, false); } void blk_mq_add_to_requeue_list(struct request *rq, bool at_head, bool kick_requeue_list) { struct request_queue *q = rq->q; unsigned long flags; /* * We abuse this flag that is otherwise used by the I/O scheduler to * request head insertion from the workqueue. */ BUG_ON(rq->rq_flags & RQF_SOFTBARRIER); spin_lock_irqsave(&q->requeue_lock, flags); if (at_head) { rq->rq_flags |= RQF_SOFTBARRIER; list_add(&rq->queuelist, &q->requeue_list); } else { list_add_tail(&rq->queuelist, &q->requeue_list); } spin_unlock_irqrestore(&q->requeue_lock, flags); if (kick_requeue_list) blk_mq_kick_requeue_list(q); } void blk_mq_kick_requeue_list(struct request_queue *q) { kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0); } EXPORT_SYMBOL(blk_mq_kick_requeue_list); void blk_mq_delay_kick_requeue_list(struct request_queue *q, unsigned long msecs) { kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, msecs_to_jiffies(msecs)); } EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list); struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) { if (tag < tags->nr_tags) { prefetch(tags->rqs[tag]); return tags->rqs[tag]; } return NULL; } EXPORT_SYMBOL(blk_mq_tag_to_rq); static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx *hctx, struct request *rq, void *priv, bool reserved) { /* * If we find a request that is inflight and the queue matches, * we know the queue is busy. Return false to stop the iteration. */ if (rq->state == MQ_RQ_IN_FLIGHT && rq->q == hctx->queue) { bool *busy = priv; *busy = true; return false; } return true; } bool blk_mq_queue_inflight(struct request_queue *q) { bool busy = false; blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy); return busy; } EXPORT_SYMBOL_GPL(blk_mq_queue_inflight); static void blk_mq_rq_timed_out(struct request *req, bool reserved) { req->rq_flags |= RQF_TIMED_OUT; if (req->q->mq_ops->timeout) { enum blk_eh_timer_return ret; ret = req->q->mq_ops->timeout(req, reserved); if (ret == BLK_EH_DONE) return; WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER); } blk_add_timer(req); } static bool blk_mq_req_expired(struct request *rq, unsigned long *next) { unsigned long deadline; if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT) return false; if (rq->rq_flags & RQF_TIMED_OUT) return false; deadline = READ_ONCE(rq->deadline); if (time_after_eq(jiffies, deadline)) return true; if (*next == 0) *next = deadline; else if (time_after(*next, deadline)) *next = deadline; return false; } static bool blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, struct request *rq, void *priv, bool reserved) { unsigned long *next = priv; /* * Just do a quick check if it is expired before locking the request in * so we're not unnecessarilly synchronizing across CPUs. */ if (!blk_mq_req_expired(rq, next)) return true; /* * We have reason to believe the request may be expired. Take a * reference on the request to lock this request lifetime into its * currently allocated context to prevent it from being reallocated in * the event the completion by-passes this timeout handler. * * If the reference was already released, then the driver beat the * timeout handler to posting a natural completion. */ if (!refcount_inc_not_zero(&rq->ref)) return true; /* * The request is now locked and cannot be reallocated underneath the * timeout handler's processing. Re-verify this exact request is truly * expired; if it is not expired, then the request was completed and * reallocated as a new request. */ if (blk_mq_req_expired(rq, next)) blk_mq_rq_timed_out(rq, reserved); if (is_flush_rq(rq, hctx)) rq->end_io(rq, 0); else if (refcount_dec_and_test(&rq->ref)) __blk_mq_free_request(rq); return true; } static void blk_mq_timeout_work(struct work_struct *work) { struct request_queue *q = container_of(work, struct request_queue, timeout_work); unsigned long next = 0; struct blk_mq_hw_ctx *hctx; int i; /* A deadlock might occur if a request is stuck requiring a * timeout at the same time a queue freeze is waiting * completion, since the timeout code would not be able to * acquire the queue reference here. * * That's why we don't use blk_queue_enter here; instead, we use * percpu_ref_tryget directly, because we need to be able to * obtain a reference even in the short window between the queue * starting to freeze, by dropping the first reference in * blk_freeze_queue_start, and the moment the last request is * consumed, marked by the instant q_usage_counter reaches * zero. */ if (!percpu_ref_tryget(&q->q_usage_counter)) return; blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &next); if (next != 0) { mod_timer(&q->timeout, next); } else { /* * Request timeouts are handled as a forward rolling timer. If * we end up here it means that no requests are pending and * also that no request has been pending for a while. Mark * each hctx as idle. */ queue_for_each_hw_ctx(q, hctx, i) { /* the hctx may be unmapped, so check it here */ if (blk_mq_hw_queue_mapped(hctx)) blk_mq_tag_idle(hctx); } } blk_queue_exit(q); } struct flush_busy_ctx_data { struct blk_mq_hw_ctx *hctx; struct list_head *list; }; static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data) { struct flush_busy_ctx_data *flush_data = data; struct blk_mq_hw_ctx *hctx = flush_data->hctx; struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; enum hctx_type type = hctx->type; spin_lock(&ctx->lock); list_splice_tail_init(&ctx->rq_lists[type], flush_data->list); sbitmap_clear_bit(sb, bitnr); spin_unlock(&ctx->lock); return true; } /* * Process software queues that have been marked busy, splicing them * to the for-dispatch */ void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) { struct flush_busy_ctx_data data = { .hctx = hctx, .list = list, }; sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data); } EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs); struct dispatch_rq_data { struct blk_mq_hw_ctx *hctx; struct request *rq; }; static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr, void *data) { struct dispatch_rq_data *dispatch_data = data; struct blk_mq_hw_ctx *hctx = dispatch_data->hctx; struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; enum hctx_type type = hctx->type; spin_lock(&ctx->lock); if (!list_empty(&ctx->rq_lists[type])) { dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next); list_del_init(&dispatch_data->rq->queuelist); if (list_empty(&ctx->rq_lists[type])) sbitmap_clear_bit(sb, bitnr); } spin_unlock(&ctx->lock); return !dispatch_data->rq; } struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *start) { unsigned off = start ? start->index_hw[hctx->type] : 0; struct dispatch_rq_data data = { .hctx = hctx, .rq = NULL, }; __sbitmap_for_each_set(&hctx->ctx_map, off, dispatch_rq_from_ctx, &data); return data.rq; } static inline unsigned int queued_to_index(unsigned int queued) { if (!queued) return 0; return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1); } bool blk_mq_get_driver_tag(struct request *rq) { struct blk_mq_alloc_data data = { .q = rq->q, .hctx = rq->mq_hctx, .flags = BLK_MQ_REQ_NOWAIT, .cmd_flags = rq->cmd_flags, }; bool shared; if (rq->tag != -1) return true; if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag)) data.flags |= BLK_MQ_REQ_RESERVED; shared = blk_mq_tag_busy(data.hctx); rq->tag = blk_mq_get_tag(&data); if (rq->tag >= 0) { if (shared) { rq->rq_flags |= RQF_MQ_INFLIGHT; atomic_inc(&data.hctx->nr_active); } data.hctx->tags->rqs[rq->tag] = rq; } return rq->tag != -1; } static int blk_mq_dispatch_wake(wait_queue_entry_t *wait, unsigned mode, int flags, void *key) { struct blk_mq_hw_ctx *hctx; hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait); spin_lock(&hctx->dispatch_wait_lock); if (!list_empty(&wait->entry)) { struct sbitmap_queue *sbq; list_del_init(&wait->entry); sbq = &hctx->tags->bitmap_tags; atomic_dec(&sbq->ws_active); } spin_unlock(&hctx->dispatch_wait_lock); blk_mq_run_hw_queue(hctx, true); return 1; } /* * Mark us waiting for a tag. For shared tags, this involves hooking us into * the tag wakeups. For non-shared tags, we can simply mark us needing a * restart. For both cases, take care to check the condition again after * marking us as waiting. */ static bool blk_mq_mark_tag_wait(struct blk_mq_hw_ctx *hctx, struct request *rq) { struct sbitmap_queue *sbq = &hctx->tags->bitmap_tags; struct wait_queue_head *wq; wait_queue_entry_t *wait; bool ret; if (!(hctx->flags & BLK_MQ_F_TAG_SHARED)) { blk_mq_sched_mark_restart_hctx(hctx); /* * It's possible that a tag was freed in the window between the * allocation failure and adding the hardware queue to the wait * queue. * * Don't clear RESTART here, someone else could have set it. * At most this will cost an extra queue run. */ return blk_mq_get_driver_tag(rq); } wait = &hctx->dispatch_wait; if (!list_empty_careful(&wait->entry)) return false; wq = &bt_wait_ptr(sbq, hctx)->wait; spin_lock_irq(&wq->lock); spin_lock(&hctx->dispatch_wait_lock); if (!list_empty(&wait->entry)) { spin_unlock(&hctx->dispatch_wait_lock); spin_unlock_irq(&wq->lock); return false; } atomic_inc(&sbq->ws_active); wait->flags &= ~WQ_FLAG_EXCLUSIVE; __add_wait_queue(wq, wait); /* * It's possible that a tag was freed in the window between the * allocation failure and adding the hardware queue to the wait * queue. */ ret = blk_mq_get_driver_tag(rq); if (!ret) { spin_unlock(&hctx->dispatch_wait_lock); spin_unlock_irq(&wq->lock); return false; } /* * We got a tag, remove ourselves from the wait queue to ensure * someone else gets the wakeup. */ list_del_init(&wait->entry); atomic_dec(&sbq->ws_active); spin_unlock(&hctx->dispatch_wait_lock); spin_unlock_irq(&wq->lock); return true; } #define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8 #define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4 /* * Update dispatch busy with the Exponential Weighted Moving Average(EWMA): * - EWMA is one simple way to compute running average value * - weight(7/8 and 1/8) is applied so that it can decrease exponentially * - take 4 as factor for avoiding to get too small(0) result, and this * factor doesn't matter because EWMA decreases exponentially */ static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy) { unsigned int ewma; if (hctx->queue->elevator) return; ewma = hctx->dispatch_busy; if (!ewma && !busy) return; ewma *= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT - 1; if (busy) ewma += 1 << BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR; ewma /= BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT; hctx->dispatch_busy = ewma; } #define BLK_MQ_RESOURCE_DELAY 3 /* ms units */ static void blk_mq_handle_dev_resource(struct request *rq, struct list_head *list) { struct request *next = list_first_entry_or_null(list, struct request, queuelist); /* * If an I/O scheduler has been configured and we got a driver tag for * the next request already, free it. */ if (next) blk_mq_put_driver_tag(next); list_add(&rq->queuelist, list); __blk_mq_requeue_request(rq); } /* * Returns true if we did some work AND can potentially do more. */ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list, bool got_budget) { struct blk_mq_hw_ctx *hctx; struct request *rq, *nxt; bool no_tag = false; int errors, queued; blk_status_t ret = BLK_STS_OK; if (list_empty(list)) return false; WARN_ON(!list_is_singular(list) && got_budget); /* * Now process all the entries, sending them to the driver. */ errors = queued = 0; do { struct blk_mq_queue_data bd; rq = list_first_entry(list, struct request, queuelist); hctx = rq->mq_hctx; if (!got_budget && !blk_mq_get_dispatch_budget(hctx)) { blk_mq_put_driver_tag(rq); break; } if (!blk_mq_get_driver_tag(rq)) { /* * The initial allocation attempt failed, so we need to * rerun the hardware queue when a tag is freed. The * waitqueue takes care of that. If the queue is run * before we add this entry back on the dispatch list, * we'll re-run it below. */ if (!blk_mq_mark_tag_wait(hctx, rq)) { blk_mq_put_dispatch_budget(hctx); /* * For non-shared tags, the RESTART check * will suffice. */ if (hctx->flags & BLK_MQ_F_TAG_SHARED) no_tag = true; break; } } list_del_init(&rq->queuelist); bd.rq = rq; /* * Flag last if we have no more requests, or if we have more * but can't assign a driver tag to it. */ if (list_empty(list)) bd.last = true; else { nxt = list_first_entry(list, struct request, queuelist); bd.last = !blk_mq_get_driver_tag(nxt); } ret = q->mq_ops->queue_rq(hctx, &bd); if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { blk_mq_handle_dev_resource(rq, list); break; } if (unlikely(ret != BLK_STS_OK)) { errors++; blk_mq_end_request(rq, BLK_STS_IOERR); continue; } queued++; } while (!list_empty(list)); hctx->dispatched[queued_to_index(queued)]++; /* * Any items that need requeuing? Stuff them into hctx->dispatch, * that is where we will continue on next queue run. */ if (!list_empty(list)) { bool needs_restart; /* * If we didn't flush the entire list, we could have told * the driver there was more coming, but that turned out to * be a lie. */ if (q->mq_ops->commit_rqs && queued) q->mq_ops->commit_rqs(hctx); spin_lock(&hctx->lock); list_splice_tail_init(list, &hctx->dispatch); spin_unlock(&hctx->lock); /* * If SCHED_RESTART was set by the caller of this function and * it is no longer set that means that it was cleared by another * thread and hence that a queue rerun is needed. * * If 'no_tag' is set, that means that we failed getting * a driver tag with an I/O scheduler attached. If our dispatch * waitqueue is no longer active, ensure that we run the queue * AFTER adding our entries back to the list. * * If no I/O scheduler has been configured it is possible that * the hardware queue got stopped and restarted before requests * were pushed back onto the dispatch list. Rerun the queue to * avoid starvation. Notes: * - blk_mq_run_hw_queue() checks whether or not a queue has * been stopped before rerunning a queue. * - Some but not all block drivers stop a queue before * returning BLK_STS_RESOURCE. Two exceptions are scsi-mq * and dm-rq. * * If driver returns BLK_STS_RESOURCE and SCHED_RESTART * bit is set, run queue after a delay to avoid IO stalls * that could otherwise occur if the queue is idle. */ needs_restart = blk_mq_sched_needs_restart(hctx); if (!needs_restart || (no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) blk_mq_run_hw_queue(hctx, true); else if (needs_restart && (ret == BLK_STS_RESOURCE)) blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY); blk_mq_update_dispatch_busy(hctx, true); return false; } else blk_mq_update_dispatch_busy(hctx, false); /* * If the host/device is unable to accept more work, inform the * caller of that. */ if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) return false; return (queued + errors) != 0; } /** * __blk_mq_run_hw_queue - Run a hardware queue. * @hctx: Pointer to the hardware queue to run. * * Send pending requests to the hardware. */ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) { int srcu_idx; /* * We should be running this queue from one of the CPUs that * are mapped to it. * * There are at least two related races now between setting * hctx->next_cpu from blk_mq_hctx_next_cpu() and running * __blk_mq_run_hw_queue(): * * - hctx->next_cpu is found offline in blk_mq_hctx_next_cpu(), * but later it becomes online, then this warning is harmless * at all * * - hctx->next_cpu is found online in blk_mq_hctx_next_cpu(), * but later it becomes offline, then the warning can't be * triggered, and we depend on blk-mq timeout handler to * handle dispatched requests to this hctx */ if (!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && cpu_online(hctx->next_cpu)) { printk(KERN_WARNING "run queue from wrong CPU %d, hctx %s\n", raw_smp_processor_id(), cpumask_empty(hctx->cpumask) ? "inactive": "active"); dump_stack(); } /* * We can't run the queue inline with ints disabled. Ensure that * we catch bad users of this early. */ WARN_ON_ONCE(in_interrupt()); might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); hctx_lock(hctx, &srcu_idx); blk_mq_sched_dispatch_requests(hctx); hctx_unlock(hctx, srcu_idx); } static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx) { int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask); if (cpu >= nr_cpu_ids) cpu = cpumask_first(hctx->cpumask); return cpu; } /* * It'd be great if the workqueue API had a way to pass * in a mask and had some smarts for more clever placement. * For now we just round-robin here, switching for every * BLK_MQ_CPU_WORK_BATCH queued items. */ static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) { bool tried = false; int next_cpu = hctx->next_cpu; if (hctx->queue->nr_hw_queues == 1) return WORK_CPU_UNBOUND; if (--hctx->next_cpu_batch <= 0) { select_cpu: next_cpu = cpumask_next_and(next_cpu, hctx->cpumask, cpu_online_mask); if (next_cpu >= nr_cpu_ids) next_cpu = blk_mq_first_mapped_cpu(hctx); hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; } /* * Do unbound schedule if we can't find a online CPU for this hctx, * and it should only happen in the path of handling CPU DEAD. */ if (!cpu_online(next_cpu)) { if (!tried) { tried = true; goto select_cpu; } /* * Make sure to re-select CPU next time once after CPUs * in hctx->cpumask become online again. */ hctx->next_cpu = next_cpu; hctx->next_cpu_batch = 1; return WORK_CPU_UNBOUND; } hctx->next_cpu = next_cpu; return next_cpu; } /** * __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue. * @hctx: Pointer to the hardware queue to run. * @async: If we want to run the queue asynchronously. * @msecs: Microseconds of delay to wait before running the queue. * * If !@async, try to run the queue now. Else, run the queue asynchronously and * with a delay of @msecs. */ static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, unsigned long msecs) { if (unlikely(blk_mq_hctx_stopped(hctx))) return; if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) { int cpu = get_cpu(); if (cpumask_test_cpu(cpu, hctx->cpumask)) { __blk_mq_run_hw_queue(hctx); put_cpu(); return; } put_cpu(); } kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, msecs_to_jiffies(msecs)); } /** * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously. * @hctx: Pointer to the hardware queue to run. * @msecs: Microseconds of delay to wait before running the queue. * * Run a hardware queue asynchronously with a delay of @msecs. */ void blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) { __blk_mq_delay_run_hw_queue(hctx, true, msecs); } EXPORT_SYMBOL(blk_mq_delay_run_hw_queue); /** * blk_mq_run_hw_queue - Start to run a hardware queue. * @hctx: Pointer to the hardware queue to run. * @async: If we want to run the queue asynchronously. * * Check if the request queue is not in a quiesced state and if there are * pending requests to be sent. If this is true, run the queue to send requests * to hardware. */ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) { int srcu_idx; bool need_run; /* * When queue is quiesced, we may be switching io scheduler, or * updating nr_hw_queues, or other things, and we can't run queue * any more, even __blk_mq_hctx_has_pending() can't be called safely. * * And queue will be rerun in blk_mq_unquiesce_queue() if it is * quiesced. */ hctx_lock(hctx, &srcu_idx); need_run = !blk_queue_quiesced(hctx->queue) && blk_mq_hctx_has_pending(hctx); hctx_unlock(hctx, srcu_idx); if (need_run) __blk_mq_delay_run_hw_queue(hctx, async, 0); } EXPORT_SYMBOL(blk_mq_run_hw_queue); /** * blk_mq_run_hw_queue - Run all hardware queues in a request queue. * @q: Pointer to the request queue to run. * @async: If we want to run the queue asynchronously. */ void blk_mq_run_hw_queues(struct request_queue *q, bool async) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) { if (blk_mq_hctx_stopped(hctx)) continue; blk_mq_run_hw_queue(hctx, async); } } EXPORT_SYMBOL(blk_mq_run_hw_queues); /** * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped * @q: request queue. * * The caller is responsible for serializing this function against * blk_mq_{start,stop}_hw_queue(). */ bool blk_mq_queue_stopped(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) if (blk_mq_hctx_stopped(hctx)) return true; return false; } EXPORT_SYMBOL(blk_mq_queue_stopped); /* * This function is often used for pausing .queue_rq() by driver when * there isn't enough resource or some conditions aren't satisfied, and * BLK_STS_RESOURCE is usually returned. * * We do not guarantee that dispatch can be drained or blocked * after blk_mq_stop_hw_queue() returns. Please use * blk_mq_quiesce_queue() for that requirement. */ void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) { cancel_delayed_work(&hctx->run_work); set_bit(BLK_MQ_S_STOPPED, &hctx->state); } EXPORT_SYMBOL(blk_mq_stop_hw_queue); /* * This function is often used for pausing .queue_rq() by driver when * there isn't enough resource or some conditions aren't satisfied, and * BLK_STS_RESOURCE is usually returned. * * We do not guarantee that dispatch can be drained or blocked * after blk_mq_stop_hw_queues() returns. Please use * blk_mq_quiesce_queue() for that requirement. */ void blk_mq_stop_hw_queues(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) blk_mq_stop_hw_queue(hctx); } EXPORT_SYMBOL(blk_mq_stop_hw_queues); void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) { clear_bit(BLK_MQ_S_STOPPED, &hctx->state); blk_mq_run_hw_queue(hctx, false); } EXPORT_SYMBOL(blk_mq_start_hw_queue); void blk_mq_start_hw_queues(struct request_queue *q) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) blk_mq_start_hw_queue(hctx); } EXPORT_SYMBOL(blk_mq_start_hw_queues); void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) { if (!blk_mq_hctx_stopped(hctx)) return; clear_bit(BLK_MQ_S_STOPPED, &hctx->state); blk_mq_run_hw_queue(hctx, async); } EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue); void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) blk_mq_start_stopped_hw_queue(hctx, async); } EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); static void blk_mq_run_work_fn(struct work_struct *work) { struct blk_mq_hw_ctx *hctx; hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); /* * If we are stopped, don't run the queue. */ if (test_bit(BLK_MQ_S_STOPPED, &hctx->state)) return; __blk_mq_run_hw_queue(hctx); } static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx, struct request *rq, bool at_head) { struct blk_mq_ctx *ctx = rq->mq_ctx; enum hctx_type type = hctx->type; lockdep_assert_held(&ctx->lock); trace_block_rq_insert(hctx->queue, rq); if (at_head) list_add(&rq->queuelist, &ctx->rq_lists[type]); else list_add_tail(&rq->queuelist, &ctx->rq_lists[type]); } void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, bool at_head) { struct blk_mq_ctx *ctx = rq->mq_ctx; lockdep_assert_held(&ctx->lock); __blk_mq_insert_req_list(hctx, rq, at_head); blk_mq_hctx_mark_pending(hctx, ctx); } /** * blk_mq_request_bypass_insert - Insert a request at dispatch list. * @rq: Pointer to request to be inserted. * @run_queue: If we should run the hardware queue after inserting the request. * * Should only be used carefully, when the caller knows we want to * bypass a potential IO scheduler on the target device. */ void blk_mq_request_bypass_insert(struct request *rq, bool at_head, bool run_queue) { struct blk_mq_hw_ctx *hctx = rq->mq_hctx; spin_lock(&hctx->lock); if (at_head) list_add(&rq->queuelist, &hctx->dispatch); else list_add_tail(&rq->queuelist, &hctx->dispatch); spin_unlock(&hctx->lock); if (run_queue) blk_mq_run_hw_queue(hctx, false); } void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx, struct list_head *list) { struct request *rq; enum hctx_type type = hctx->type; /* * preemption doesn't flush plug list, so it's possible ctx->cpu is * offline now */ list_for_each_entry(rq, list, queuelist) { BUG_ON(rq->mq_ctx != ctx); trace_block_rq_insert(hctx->queue, rq); } spin_lock(&ctx->lock); list_splice_tail_init(list, &ctx->rq_lists[type]); blk_mq_hctx_mark_pending(hctx, ctx); spin_unlock(&ctx->lock); } 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); if (rqa->mq_ctx != rqb->mq_ctx) return rqa->mq_ctx > rqb->mq_ctx; if (rqa->mq_hctx != rqb->mq_hctx) return rqa->mq_hctx > rqb->mq_hctx; return blk_rq_pos(rqa) > blk_rq_pos(rqb); } void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) { LIST_HEAD(list); if (list_empty(&plug->mq_list)) return; list_splice_init(&plug->mq_list, &list); if (plug->rq_count > 2 && plug->multiple_queues) list_sort(NULL, &list, plug_rq_cmp); plug->rq_count = 0; do { struct list_head rq_list; struct request *rq, *head_rq = list_entry_rq(list.next); struct list_head *pos = &head_rq->queuelist; /* skip first */ struct blk_mq_hw_ctx *this_hctx = head_rq->mq_hctx; struct blk_mq_ctx *this_ctx = head_rq->mq_ctx; unsigned int depth = 1; list_for_each_continue(pos, &list) { rq = list_entry_rq(pos); BUG_ON(!rq->q); if (rq->mq_hctx != this_hctx || rq->mq_ctx != this_ctx) break; depth++; } list_cut_before(&rq_list, &list, pos); trace_block_unplug(head_rq->q, depth, !from_schedule); blk_mq_sched_insert_requests(this_hctx, this_ctx, &rq_list, from_schedule); } while(!list_empty(&list)); } static void blk_mq_bio_to_request(struct request *rq, struct bio *bio, unsigned int nr_segs) { if (bio->bi_opf & REQ_RAHEAD) rq->cmd_flags |= REQ_FAILFAST_MASK; rq->__sector = bio->bi_iter.bi_sector; rq->write_hint = bio->bi_write_hint; blk_rq_bio_prep(rq, bio, nr_segs); blk_account_io_start(rq, true); } static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, blk_qc_t *cookie, bool last) { struct request_queue *q = rq->q; struct blk_mq_queue_data bd = { .rq = rq, .last = last, }; blk_qc_t new_cookie; blk_status_t ret; new_cookie = request_to_qc_t(hctx, rq); /* * For OK queue, we are done. For error, caller may kill it. * Any other error (busy), just add it to our list as we * previously would have done. */ ret = q->mq_ops->queue_rq(hctx, &bd); switch (ret) { case BLK_STS_OK: blk_mq_update_dispatch_busy(hctx, false); *cookie = new_cookie; break; case BLK_STS_RESOURCE: case BLK_STS_DEV_RESOURCE: blk_mq_update_dispatch_busy(hctx, true); __blk_mq_requeue_request(rq); break; default: blk_mq_update_dispatch_busy(hctx, false); *cookie = BLK_QC_T_NONE; break; } return ret; } static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, blk_qc_t *cookie, bool bypass_insert, bool last) { struct request_queue *q = rq->q; bool run_queue = true; /* * RCU or SRCU read lock is needed before checking quiesced flag. * * When queue is stopped or quiesced, ignore 'bypass_insert' from * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller, * and avoid driver to try to dispatch again. */ if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { run_queue = false; bypass_insert = false; goto insert; } if (q->elevator && !bypass_insert) goto insert; if (!blk_mq_get_dispatch_budget(hctx)) goto insert; if (!blk_mq_get_driver_tag(rq)) { blk_mq_put_dispatch_budget(hctx); goto insert; } return __blk_mq_issue_directly(hctx, rq, cookie, last); insert: if (bypass_insert) return BLK_STS_RESOURCE; blk_mq_request_bypass_insert(rq, false, run_queue); return BLK_STS_OK; } /** * blk_mq_try_issue_directly - Try to send a request directly to device driver. * @hctx: Pointer of the associated hardware queue. * @rq: Pointer to request to be sent. * @cookie: Request queue cookie. * * If the device has enough resources to accept a new request now, send the * request directly to device driver. Else, insert at hctx->dispatch queue, so * we can try send it another time in the future. Requests inserted at this * queue have higher priority. */ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, struct request *rq, blk_qc_t *cookie) { blk_status_t ret; int srcu_idx; might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); hctx_lock(hctx, &srcu_idx); ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true); if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) blk_mq_request_bypass_insert(rq, false, true); else if (ret != BLK_STS_OK) blk_mq_end_request(rq, ret); hctx_unlock(hctx, srcu_idx); } blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) { blk_status_t ret; int srcu_idx; blk_qc_t unused_cookie; struct blk_mq_hw_ctx *hctx = rq->mq_hctx; hctx_lock(hctx, &srcu_idx); ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true, last); hctx_unlock(hctx, srcu_idx); return ret; } void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, struct list_head *list) { int queued = 0; while (!list_empty(list)) { blk_status_t ret; struct request *rq = list_first_entry(list, struct request, queuelist); list_del_init(&rq->queuelist); ret = blk_mq_request_issue_directly(rq, list_empty(list)); if (ret != BLK_STS_OK) { if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { blk_mq_request_bypass_insert(rq, false, list_empty(list)); break; } blk_mq_end_request(rq, ret); } else queued++; } /* * If we didn't flush the entire list, we could have told * the driver there was more coming, but that turned out to * be a lie. */ if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs && queued) hctx->queue->mq_ops->commit_rqs(hctx); } static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) { list_add_tail(&rq->queuelist, &plug->mq_list); plug->rq_count++; if (!plug->multiple_queues && !list_is_singular(&plug->mq_list)) { struct request *tmp; tmp = list_first_entry(&plug->mq_list, struct request, queuelist); if (tmp->q != rq->q) plug->multiple_queues = true; } } /** * blk_mq_make_request - Create and send a request to block device. * @q: Request queue pointer. * @bio: Bio pointer. * * Builds up a request structure from @q and @bio and send to the device. The * request may not be queued directly to hardware if: * * This request can be merged with another one * * We want to place request at plug queue for possible future merging * * There is an IO scheduler active at this queue * * It will not queue the request if there is an error with the bio, or at the * request creation. * * Returns: Request queue cookie. */ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) { const int is_sync = op_is_sync(bio->bi_opf); const int is_flush_fua = op_is_flush(bio->bi_opf); struct blk_mq_alloc_data data = { .flags = 0}; struct request *rq; struct blk_plug *plug; struct request *same_queue_rq = NULL; unsigned int nr_segs; blk_qc_t cookie; blk_queue_bounce(q, &bio); __blk_queue_split(q, &bio, &nr_segs); if (!bio_integrity_prep(bio)) return BLK_QC_T_NONE; if (!is_flush_fua && !blk_queue_nomerges(q) && blk_attempt_plug_merge(q, bio, nr_segs, &same_queue_rq)) return BLK_QC_T_NONE; if (blk_mq_sched_bio_merge(q, bio, nr_segs)) return BLK_QC_T_NONE; rq_qos_throttle(q, bio); data.cmd_flags = bio->bi_opf; rq = blk_mq_get_request(q, bio, &data); if (unlikely(!rq)) { rq_qos_cleanup(q, bio); if (bio->bi_opf & REQ_NOWAIT) bio_wouldblock_error(bio); return BLK_QC_T_NONE; } trace_block_getrq(q, bio, bio->bi_opf); rq_qos_track(q, rq, bio); cookie = request_to_qc_t(data.hctx, rq); blk_mq_bio_to_request(rq, bio, nr_segs); plug = blk_mq_plug(q, bio); if (unlikely(is_flush_fua)) { /* Bypass scheduler for flush requests */ blk_insert_flush(rq); blk_mq_run_hw_queue(data.hctx, true); } else if (plug && (q->nr_hw_queues == 1 || q->mq_ops->commit_rqs || !blk_queue_nonrot(q))) { /* * Use plugging if we have a ->commit_rqs() hook as well, as * we know the driver uses bd->last in a smart fashion. * * Use normal plugging if this disk is slow HDD, as sequential * IO may benefit a lot from plug merging. */ unsigned int request_count = plug->rq_count; struct request *last = NULL; if (!request_count) trace_block_plug(q); else last = list_entry_rq(plug->mq_list.prev); if (request_count >= BLK_MAX_REQUEST_COUNT || (last && blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { blk_flush_plug_list(plug, false); trace_block_plug(q); } blk_add_rq_to_plug(plug, rq); } else if (q->elevator) { /* Insert the request at the IO scheduler queue */ blk_mq_sched_insert_request(rq, false, true, true); } else if (plug && !blk_queue_nomerges(q)) { /* * We do limited plugging. If the bio can be merged, do that. * Otherwise the existing request in the plug list will be * issued. So the plug list will have one request at most * The plug list might get flushed before this. If that happens, * the plug list is empty, and same_queue_rq is invalid. */ if (list_empty(&plug->mq_list)) same_queue_rq = NULL; if (same_queue_rq) { list_del_init(&same_queue_rq->queuelist); plug->rq_count--; } blk_add_rq_to_plug(plug, rq); trace_block_plug(q); if (same_queue_rq) { data.hctx = same_queue_rq->mq_hctx; trace_block_unplug(q, 1, true); blk_mq_try_issue_directly(data.hctx, same_queue_rq, &cookie); } } else if ((q->nr_hw_queues > 1 && is_sync) || !data.hctx->dispatch_busy) { /* * There is no scheduler and we can try to send directly * to the hardware. */ blk_mq_try_issue_directly(data.hctx, rq, &cookie); } else { /* Default case. */ blk_mq_sched_insert_request(rq, false, true, true); } return cookie; } void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, unsigned int hctx_idx) { struct page *page; if (tags->rqs && set->ops->exit_request) { int i; for (i = 0; i < tags->nr_tags; i++) { struct request *rq = tags->static_rqs[i]; if (!rq) continue; set->ops->exit_request(set, rq, hctx_idx); tags->static_rqs[i] = NULL; } } while (!list_empty(&tags->page_list)) { page = list_first_entry(&tags->page_list, struct page, lru); list_del_init(&page->lru); /* * Remove kmemleak object previously allocated in * blk_mq_alloc_rqs(). */ kmemleak_free(page_address(page)); __free_pages(page, page->private); } } void blk_mq_free_rq_map(struct blk_mq_tags *tags) { kfree(tags->rqs); tags->rqs = NULL; kfree(tags->static_rqs); tags->static_rqs = NULL; blk_mq_free_tags(tags); } struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, unsigned int hctx_idx, unsigned int nr_tags, unsigned int reserved_tags) { struct blk_mq_tags *tags; int node; node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx); if (node == NUMA_NO_NODE) node = set->numa_node; tags = blk_mq_init_tags(nr_tags, reserved_tags, node, BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags)); if (!tags) return NULL; tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, node); if (!tags->rqs) { blk_mq_free_tags(tags); return NULL; } tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, node); if (!tags->static_rqs) { kfree(tags->rqs); blk_mq_free_tags(tags); return NULL; } return tags; } static size_t order_to_size(unsigned int order) { return (size_t)PAGE_SIZE << order; } static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, unsigned int hctx_idx, int node) { int ret; if (set->ops->init_request) { ret = set->ops->init_request(set, rq, hctx_idx, node); if (ret) return ret; } WRITE_ONCE(rq->state, MQ_RQ_IDLE); return 0; } int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, unsigned int hctx_idx, unsigned int depth) { unsigned int i, j, entries_per_page, max_order = 4; size_t rq_size, left; int node; node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx); if (node == NUMA_NO_NODE) node = set->numa_node; INIT_LIST_HEAD(&tags->page_list); /* * rq_size is the size of the request plus driver payload, rounded * to the cacheline size */ rq_size = round_up(sizeof(struct request) + set->cmd_size, cache_line_size()); left = rq_size * depth; for (i = 0; i < depth; ) { int this_order = max_order; struct page *page; int to_do; void *p; while (this_order && left < order_to_size(this_order - 1)) this_order--; do { page = alloc_pages_node(node, GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO, this_order); if (page) break; if (!this_order--) break; if (order_to_size(this_order) < rq_size) break; } while (1); if (!page) goto fail; page->private = this_order; list_add_tail(&page->lru, &tags->page_list); p = page_address(page); /* * Allow kmemleak to scan these pages as they contain pointers * to additional allocations like via ops->init_request(). */ kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO); entries_per_page = order_to_size(this_order) / rq_size; to_do = min(entries_per_page, depth - i); left -= to_do * rq_size; for (j = 0; j < to_do; j++) { struct request *rq = p; tags->static_rqs[i] = rq; if (blk_mq_init_request(set, rq, hctx_idx, node)) { tags->static_rqs[i] = NULL; goto fail; } p += rq_size; i++; } } return 0; fail: blk_mq_free_rqs(set, tags, hctx_idx); return -ENOMEM; } /* * 'cpu' is going away. splice any existing rq_list entries from this * software queue to the hw queue dispatch list, and ensure that it * gets run. */ static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node) { struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx; LIST_HEAD(tmp); enum hctx_type type; hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead); ctx = __blk_mq_get_ctx(hctx->queue, cpu); type = hctx->type; spin_lock(&ctx->lock); if (!list_empty(&ctx->rq_lists[type])) { list_splice_init(&ctx->rq_lists[type], &tmp); blk_mq_hctx_clear_pending(hctx, ctx); } spin_unlock(&ctx->lock); if (list_empty(&tmp)) return 0; spin_lock(&hctx->lock); list_splice_tail_init(&tmp, &hctx->dispatch); spin_unlock(&hctx->lock); blk_mq_run_hw_queue(hctx, true); return 0; } static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx) { cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead); } /* hctx->ctxs will be freed in queue's release handler */ static void blk_mq_exit_hctx(struct request_queue *q, struct blk_mq_tag_set *set, struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) { if (blk_mq_hw_queue_mapped(hctx)) blk_mq_tag_idle(hctx); if (set->ops->exit_request) set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx); if (set->ops->exit_hctx) set->ops->exit_hctx(hctx, hctx_idx); blk_mq_remove_cpuhp(hctx); spin_lock(&q->unused_hctx_lock); list_add(&hctx->hctx_list, &q->unused_hctx_list); spin_unlock(&q->unused_hctx_lock); } static void blk_mq_exit_hw_queues(struct request_queue *q, struct blk_mq_tag_set *set, int nr_queue) { struct blk_mq_hw_ctx *hctx; unsigned int i; queue_for_each_hw_ctx(q, hctx, i) { if (i == nr_queue) break; blk_mq_debugfs_unregister_hctx(hctx); blk_mq_exit_hctx(q, set, hctx, i); } } static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set) { int hw_ctx_size = sizeof(struct blk_mq_hw_ctx); BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx, srcu), __alignof__(struct blk_mq_hw_ctx)) != sizeof(struct blk_mq_hw_ctx)); if (tag_set->flags & BLK_MQ_F_BLOCKING) hw_ctx_size += sizeof(struct srcu_struct); return hw_ctx_size; } static int blk_mq_init_hctx(struct request_queue *q, struct blk_mq_tag_set *set, struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) { hctx->queue_num = hctx_idx; cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead); hctx->tags = set->tags[hctx_idx]; if (set->ops->init_hctx && set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) goto unregister_cpu_notifier; if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx, hctx->numa_node)) goto exit_hctx; return 0; exit_hctx: if (set->ops->exit_hctx) set->ops->exit_hctx(hctx, hctx_idx); unregister_cpu_notifier: blk_mq_remove_cpuhp(hctx); return -1; } static struct blk_mq_hw_ctx * blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set, int node) { struct blk_mq_hw_ctx *hctx; gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY; hctx = kzalloc_node(blk_mq_hw_ctx_size(set), gfp, node); if (!hctx) goto fail_alloc_hctx; if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node)) goto free_hctx; atomic_set(&hctx->nr_active, 0); if (node == NUMA_NO_NODE) node = set->numa_node; hctx->numa_node = node; INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); spin_lock_init(&hctx->lock); INIT_LIST_HEAD(&hctx->dispatch); hctx->queue = q; hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED; INIT_LIST_HEAD(&hctx->hctx_list); /* * Allocate space for all possible cpus to avoid allocation at * runtime */ hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *), gfp, node); if (!hctx->ctxs) goto free_cpumask; if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), gfp, node)) goto free_ctxs; hctx->nr_ctx = 0; spin_lock_init(&hctx->dispatch_wait_lock); init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake); INIT_LIST_HEAD(&hctx->dispatch_wait.entry); hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp); if (!hctx->fq) goto free_bitmap; if (hctx->flags & BLK_MQ_F_BLOCKING) init_srcu_struct(hctx->srcu); blk_mq_hctx_kobj_init(hctx); return hctx; free_bitmap: sbitmap_free(&hctx->ctx_map); free_ctxs: kfree(hctx->ctxs); free_cpumask: free_cpumask_var(hctx->cpumask); free_hctx: kfree(hctx); fail_alloc_hctx: return NULL; } static void blk_mq_init_cpu_queues(struct request_queue *q, unsigned int nr_hw_queues) { struct blk_mq_tag_set *set = q->tag_set; unsigned int i, j; for_each_possible_cpu(i) { struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); struct blk_mq_hw_ctx *hctx; int k; __ctx->cpu = i; spin_lock_init(&__ctx->lock); for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++) INIT_LIST_HEAD(&__ctx->rq_lists[k]); __ctx->queue = q; /* * Set local node, IFF we have more than one hw queue. If * not, we remain on the home node of the device */ for (j = 0; j < set->nr_maps; j++) { hctx = blk_mq_map_queue_type(q, j, i); if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) hctx->numa_node = local_memory_node(cpu_to_node(i)); } } } static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx) { int ret = 0; set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx, set->queue_depth, set->reserved_tags); if (!set->tags[hctx_idx]) return false; ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx, set->queue_depth); if (!ret) return true; blk_mq_free_rq_map(set->tags[hctx_idx]); set->tags[hctx_idx] = NULL; return false; } static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set, unsigned int hctx_idx) { if (set->tags && set->tags[hctx_idx]) { blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx); blk_mq_free_rq_map(set->tags[hctx_idx]); set->tags[hctx_idx] = NULL; } } static void blk_mq_map_swqueue(struct request_queue *q) { unsigned int i, j, hctx_idx; struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx; struct blk_mq_tag_set *set = q->tag_set; queue_for_each_hw_ctx(q, hctx, i) { cpumask_clear(hctx->cpumask); hctx->nr_ctx = 0; hctx->dispatch_from = NULL; } /* * Map software to hardware queues. * * If the cpu isn't present, the cpu is mapped to first hctx. */ for_each_possible_cpu(i) { hctx_idx = set->map[HCTX_TYPE_DEFAULT].mq_map[i]; /* unmapped hw queue can be remapped after CPU topo changed */ if (!set->tags[hctx_idx] && !__blk_mq_alloc_rq_map(set, hctx_idx)) { /* * If tags initialization fail for some hctx, * that hctx won't be brought online. In this * case, remap the current ctx to hctx[0] which * is guaranteed to always have tags allocated */ set->map[HCTX_TYPE_DEFAULT].mq_map[i] = 0; } ctx = per_cpu_ptr(q->queue_ctx, i); for (j = 0; j < set->nr_maps; j++) { if (!set->map[j].nr_queues) { ctx->hctxs[j] = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT, i); continue; } hctx = blk_mq_map_queue_type(q, j, i); ctx->hctxs[j] = hctx; /* * If the CPU is already set in the mask, then we've * mapped this one already. This can happen if * devices share queues across queue maps. */ if (cpumask_test_cpu(i, hctx->cpumask)) continue; cpumask_set_cpu(i, hctx->cpumask); hctx->type = j; ctx->index_hw[hctx->type] = hctx->nr_ctx; hctx->ctxs[hctx->nr_ctx++] = ctx; /* * If the nr_ctx type overflows, we have exceeded the * amount of sw queues we can support. */ BUG_ON(!hctx->nr_ctx); } for (; j < HCTX_MAX_TYPES; j++) ctx->hctxs[j] = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT, i); } queue_for_each_hw_ctx(q, hctx, i) { /* * If no software queues are mapped to this hardware queue, * disable it and free the request entries. */ if (!hctx->nr_ctx) { /* Never unmap queue 0. We need it as a * fallback in case of a new remap fails * allocation */ if (i && set->tags[i]) blk_mq_free_map_and_requests(set, i); hctx->tags = NULL; continue; } hctx->tags = set->tags[i]; WARN_ON(!hctx->tags); /* * Set the map size to the number of mapped software queues. * This is more accurate and more efficient than looping * over all possibly mapped software queues. */ sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx); /* * Initialize batch roundrobin counts */ hctx->next_cpu = blk_mq_first_mapped_cpu(hctx); hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; } } /* * Caller needs to ensure that we're either frozen/quiesced, or that * the queue isn't live yet. */ static void queue_set_hctx_shared(struct request_queue *q, bool shared) { struct blk_mq_hw_ctx *hctx; int i; queue_for_each_hw_ctx(q, hctx, i) { if (shared) hctx->flags |= BLK_MQ_F_TAG_SHARED; else hctx->flags &= ~BLK_MQ_F_TAG_SHARED; } } static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set, bool shared) { struct request_queue *q; lockdep_assert_held(&set->tag_list_lock); list_for_each_entry(q, &set->tag_list, tag_set_list) { blk_mq_freeze_queue(q); queue_set_hctx_shared(q, shared); blk_mq_unfreeze_queue(q); } } static void blk_mq_del_queue_tag_set(struct request_queue *q) { struct blk_mq_tag_set *set = q->tag_set; mutex_lock(&set->tag_list_lock); list_del_rcu(&q->tag_set_list); if (list_is_singular(&set->tag_list)) { /* just transitioned to unshared */ set->flags &= ~BLK_MQ_F_TAG_SHARED; /* update existing queue */ blk_mq_update_tag_set_depth(set, false); } mutex_unlock(&set->tag_list_lock); INIT_LIST_HEAD(&q->tag_set_list); } static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, struct request_queue *q) { mutex_lock(&set->tag_list_lock); /* * Check to see if we're transitioning to shared (from 1 to 2 queues). */ if (!list_empty(&set->tag_list) && !(set->flags & BLK_MQ_F_TAG_SHARED)) { set->flags |= BLK_MQ_F_TAG_SHARED; /* update existing queue */ blk_mq_update_tag_set_depth(set, true); } if (set->flags & BLK_MQ_F_TAG_SHARED) queue_set_hctx_shared(q, true); list_add_tail_rcu(&q->tag_set_list, &set->tag_list); mutex_unlock(&set->tag_list_lock); } /* All allocations will be freed in release handler of q->mq_kobj */ static int blk_mq_alloc_ctxs(struct request_queue *q) { struct blk_mq_ctxs *ctxs; int cpu; ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL); if (!ctxs) return -ENOMEM; ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx); if (!ctxs->queue_ctx) goto fail; for_each_possible_cpu(cpu) { struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu); ctx->ctxs = ctxs; } q->mq_kobj = &ctxs->kobj; q->queue_ctx = ctxs->queue_ctx; return 0; fail: kfree(ctxs); return -ENOMEM; } /* * It is the actual release handler for mq, but we do it from * request queue's release handler for avoiding use-after-free * and headache because q->mq_kobj shouldn't have been introduced, * but we can't group ctx/kctx kobj without it. */ void blk_mq_release(struct request_queue *q) { struct blk_mq_hw_ctx *hctx, *next; int i; queue_for_each_hw_ctx(q, hctx, i) WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list)); /* all hctx are in .unused_hctx_list now */ list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) { list_del_init(&hctx->hctx_list); kobject_put(&hctx->kobj); } kfree(q->queue_hw_ctx); /* * release .mq_kobj and sw queue's kobject now because * both share lifetime with request queue. */ blk_mq_sysfs_deinit(q); } struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set, void *queuedata) { struct request_queue *uninit_q, *q; uninit_q = __blk_alloc_queue(set->numa_node); if (!uninit_q) return ERR_PTR(-ENOMEM); uninit_q->queuedata = queuedata; /* * Initialize the queue without an elevator. device_add_disk() will do * the initialization. */ q = blk_mq_init_allocated_queue(set, uninit_q, false); if (IS_ERR(q)) blk_cleanup_queue(uninit_q); return q; } EXPORT_SYMBOL_GPL(blk_mq_init_queue_data); struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) { return blk_mq_init_queue_data(set, NULL); } EXPORT_SYMBOL(blk_mq_init_queue); /* * Helper for setting up a queue with mq ops, given queue depth, and * the passed in mq ops flags. */ struct request_queue *blk_mq_init_sq_queue(struct blk_mq_tag_set *set, const struct blk_mq_ops *ops, unsigned int queue_depth, unsigned int set_flags) { struct request_queue *q; int ret; memset(set, 0, sizeof(*set)); set->ops = ops; set->nr_hw_queues = 1; set->nr_maps = 1; set->queue_depth = queue_depth; set->numa_node = NUMA_NO_NODE; set->flags = set_flags; ret = blk_mq_alloc_tag_set(set); if (ret) return ERR_PTR(ret); q = blk_mq_init_queue(set); if (IS_ERR(q)) { blk_mq_free_tag_set(set); return q; } return q; } EXPORT_SYMBOL(blk_mq_init_sq_queue); static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx( struct blk_mq_tag_set *set, struct request_queue *q, int hctx_idx, int node) { struct blk_mq_hw_ctx *hctx = NULL, *tmp; /* reuse dead hctx first */ spin_lock(&q->unused_hctx_lock); list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) { if (tmp->numa_node == node) { hctx = tmp; break; } } if (hctx) list_del_init(&hctx->hctx_list); spin_unlock(&q->unused_hctx_lock); if (!hctx) hctx = blk_mq_alloc_hctx(q, set, node); if (!hctx) goto fail; if (blk_mq_init_hctx(q, set, hctx, hctx_idx)) goto free_hctx; return hctx; free_hctx: kobject_put(&hctx->kobj); fail: return NULL; } static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, struct request_queue *q) { int i, j, end; struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx; if (q->nr_hw_queues < set->nr_hw_queues) { struct blk_mq_hw_ctx **new_hctxs; new_hctxs = kcalloc_node(set->nr_hw_queues, sizeof(*new_hctxs), GFP_KERNEL, set->numa_node); if (!new_hctxs) return; if (hctxs) memcpy(new_hctxs, hctxs, q->nr_hw_queues * sizeof(*hctxs)); q->queue_hw_ctx = new_hctxs; kfree(hctxs); hctxs = new_hctxs; } /* protect against switching io scheduler */ mutex_lock(&q->sysfs_lock); for (i = 0; i < set->nr_hw_queues; i++) { int node; struct blk_mq_hw_ctx *hctx; node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], i); /* * If the hw queue has been mapped to another numa node, * we need to realloc the hctx. If allocation fails, fallback * to use the previous one. */ if (hctxs[i] && (hctxs[i]->numa_node == node)) continue; hctx = blk_mq_alloc_and_init_hctx(set, q, i, node); if (hctx) { if (hctxs[i]) blk_mq_exit_hctx(q, set, hctxs[i], i); hctxs[i] = hctx; } else { if (hctxs[i]) pr_warn("Allocate new hctx on node %d fails,\ fallback to previous one on node %d\n", node, hctxs[i]->numa_node); else break; } } /* * Increasing nr_hw_queues fails. Free the newly allocated * hctxs and keep the previous q->nr_hw_queues. */ if (i != set->nr_hw_queues) { j = q->nr_hw_queues; end = i; } else { j = i; end = q->nr_hw_queues; q->nr_hw_queues = set->nr_hw_queues; } for (; j < end; j++) { struct blk_mq_hw_ctx *hctx = hctxs[j]; if (hctx) { if (hctx->tags) blk_mq_free_map_and_requests(set, j); blk_mq_exit_hctx(q, set, hctx, j); hctxs[j] = NULL; } } mutex_unlock(&q->sysfs_lock); } struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, struct request_queue *q, bool elevator_init) { /* mark the queue as mq asap */ q->mq_ops = set->ops; q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn, blk_mq_poll_stats_bkt, BLK_MQ_POLL_STATS_BKTS, q); if (!q->poll_cb) goto err_exit; if (blk_mq_alloc_ctxs(q)) goto err_poll; /* init q->mq_kobj and sw queues' kobjects */ blk_mq_sysfs_init(q); INIT_LIST_HEAD(&q->unused_hctx_list); spin_lock_init(&q->unused_hctx_lock); blk_mq_realloc_hw_ctxs(set, q); if (!q->nr_hw_queues) goto err_hctxs; INIT_WORK(&q->timeout_work, blk_mq_timeout_work); blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); q->tag_set = set; q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; if (set->nr_maps > HCTX_TYPE_POLL && set->map[HCTX_TYPE_POLL].nr_queues) blk_queue_flag_set(QUEUE_FLAG_POLL, q); q->sg_reserved_size = INT_MAX; INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work); INIT_LIST_HEAD(&q->requeue_list); spin_lock_init(&q->requeue_lock); q->make_request_fn = blk_mq_make_request; q->nr_requests = set->queue_depth; /* * Default to classic polling */ q->poll_nsec = BLK_MQ_POLL_CLASSIC; blk_mq_init_cpu_queues(q, set->nr_hw_queues); blk_mq_add_queue_tag_set(set, q); blk_mq_map_swqueue(q); if (elevator_init) elevator_init_mq(q); return q; err_hctxs: kfree(q->queue_hw_ctx); q->nr_hw_queues = 0; blk_mq_sysfs_deinit(q); err_poll: blk_stat_free_callback(q->poll_cb); q->poll_cb = NULL; err_exit: q->mq_ops = NULL; return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL(blk_mq_init_allocated_queue); /* tags can _not_ be used after returning from blk_mq_exit_queue */ void blk_mq_exit_queue(struct request_queue *q) { struct blk_mq_tag_set *set = q->tag_set; blk_mq_del_queue_tag_set(q); blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); } static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) { int i; for (i = 0; i < set->nr_hw_queues; i++) if (!__blk_mq_alloc_rq_map(set, i)) goto out_unwind; return 0; out_unwind: while (--i >= 0) blk_mq_free_rq_map(set->tags[i]); return -ENOMEM; } /* * Allocate the request maps associated with this tag_set. Note that this * may reduce the depth asked for, if memory is tight. set->queue_depth * will be updated to reflect the allocated depth. */ static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) { unsigned int depth; int err; depth = set->queue_depth; do { err = __blk_mq_alloc_rq_maps(set); if (!err) break; set->queue_depth >>= 1; if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { err = -ENOMEM; break; } } while (set->queue_depth); if (!set->queue_depth || err) { pr_err("blk-mq: failed to allocate request map\n"); return -ENOMEM; } if (depth != set->queue_depth) pr_info("blk-mq: reduced tag depth (%u -> %u)\n", depth, set->queue_depth); return 0; } static int blk_mq_update_queue_map(struct blk_mq_tag_set *set) { /* * blk_mq_map_queues() and multiple .map_queues() implementations * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the * number of hardware queues. */ if (set->nr_maps == 1) set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues; if (set->ops->map_queues && !is_kdump_kernel()) { int i; /* * transport .map_queues is usually done in the following * way: * * for (queue = 0; queue < set->nr_hw_queues; queue++) { * mask = get_cpu_mask(queue) * for_each_cpu(cpu, mask) * set->map[x].mq_map[cpu] = queue; * } * * When we need to remap, the table has to be cleared for * killing stale mapping since one CPU may not be mapped * to any hw queue. */ for (i = 0; i < set->nr_maps; i++) blk_mq_clear_mq_map(&set->map[i]); return set->ops->map_queues(set); } else { BUG_ON(set->nr_maps > 1); return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); } } static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set, int cur_nr_hw_queues, int new_nr_hw_queues) { struct blk_mq_tags **new_tags; if (cur_nr_hw_queues >= new_nr_hw_queues) return 0; new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *), GFP_KERNEL, set->numa_node); if (!new_tags) return -ENOMEM; if (set->tags) memcpy(new_tags, set->tags, cur_nr_hw_queues * sizeof(*set->tags)); kfree(set->tags); set->tags = new_tags; set->nr_hw_queues = new_nr_hw_queues; return 0; } /* * Alloc a tag set to be associated with one or more request queues. * May fail with EINVAL for various error conditions. May adjust the * requested depth down, if it's too large. In that case, the set * value will be stored in set->queue_depth. */ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) { int i, ret; BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); if (!set->nr_hw_queues) return -EINVAL; if (!set->queue_depth) return -EINVAL; if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) return -EINVAL; if (!set->ops->queue_rq) return -EINVAL; if (!set->ops->get_budget ^ !set->ops->put_budget) return -EINVAL; if (set->queue_depth > BLK_MQ_MAX_DEPTH) { pr_info("blk-mq: reduced tag depth to %u\n", BLK_MQ_MAX_DEPTH); set->queue_depth = BLK_MQ_MAX_DEPTH; } if (!set->nr_maps) set->nr_maps = 1; else if (set->nr_maps > HCTX_MAX_TYPES) return -EINVAL; /* * If a crashdump is active, then we are potentially in a very * memory constrained environment. Limit us to 1 queue and * 64 tags to prevent using too much memory. */ if (is_kdump_kernel()) { set->nr_hw_queues = 1; set->nr_maps = 1; set->queue_depth = min(64U, set->queue_depth); } /* * There is no use for more h/w queues than cpus if we just have * a single map */ if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids) set->nr_hw_queues = nr_cpu_ids; if (blk_mq_realloc_tag_set_tags(set, 0, set->nr_hw_queues) < 0) return -ENOMEM; ret = -ENOMEM; for (i = 0; i < set->nr_maps; i++) { set->map[i].mq_map = kcalloc_node(nr_cpu_ids, sizeof(set->map[i].mq_map[0]), GFP_KERNEL, set->numa_node); if (!set->map[i].mq_map) goto out_free_mq_map; set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues; } ret = blk_mq_update_queue_map(set); if (ret) goto out_free_mq_map; ret = blk_mq_alloc_rq_maps(set); if (ret) goto out_free_mq_map; mutex_init(&set->tag_list_lock); INIT_LIST_HEAD(&set->tag_list); return 0; out_free_mq_map: for (i = 0; i < set->nr_maps; i++) { kfree(set->map[i].mq_map); set->map[i].mq_map = NULL; } kfree(set->tags); set->tags = NULL; return ret; } EXPORT_SYMBOL(blk_mq_alloc_tag_set); void blk_mq_free_tag_set(struct blk_mq_tag_set *set) { int i, j; for (i = 0; i < set->nr_hw_queues; i++) blk_mq_free_map_and_requests(set, i); for (j = 0; j < set->nr_maps; j++) { kfree(set->map[j].mq_map); set->map[j].mq_map = NULL; } kfree(set->tags); set->tags = NULL; } EXPORT_SYMBOL(blk_mq_free_tag_set); int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) { struct blk_mq_tag_set *set = q->tag_set; struct blk_mq_hw_ctx *hctx; int i, ret; if (!set) return -EINVAL; if (q->nr_requests == nr) return 0; blk_mq_freeze_queue(q); blk_mq_quiesce_queue(q); ret = 0; queue_for_each_hw_ctx(q, hctx, i) { if (!hctx->tags) continue; /* * If we're using an MQ scheduler, just update the scheduler * queue depth. This is similar to what the old code would do. */ if (!hctx->sched_tags) { ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr, false); } else { ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags, nr, true); } if (ret) break; if (q->elevator && q->elevator->type->ops.depth_updated) q->elevator->type->ops.depth_updated(hctx); } if (!ret) q->nr_requests = nr; blk_mq_unquiesce_queue(q); blk_mq_unfreeze_queue(q); return ret; } /* * request_queue and elevator_type pair. * It is just used by __blk_mq_update_nr_hw_queues to cache * the elevator_type associated with a request_queue. */ struct blk_mq_qe_pair { struct list_head node; struct request_queue *q; struct elevator_type *type; }; /* * Cache the elevator_type in qe pair list and switch the * io scheduler to 'none' */ static bool blk_mq_elv_switch_none(struct list_head *head, struct request_queue *q) { struct blk_mq_qe_pair *qe; if (!q->elevator) return true; qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY); if (!qe) return false; INIT_LIST_HEAD(&qe->node); qe->q = q; qe->type = q->elevator->type; list_add(&qe->node, head); mutex_lock(&q->sysfs_lock); /* * After elevator_switch_mq, the previous elevator_queue will be * released by elevator_release. The reference of the io scheduler * module get by elevator_get will also be put. So we need to get * a reference of the io scheduler module here to prevent it to be * removed. */ __module_get(qe->type->elevator_owner); elevator_switch_mq(q, NULL); mutex_unlock(&q->sysfs_lock); return true; } static void blk_mq_elv_switch_back(struct list_head *head, struct request_queue *q) { struct blk_mq_qe_pair *qe; struct elevator_type *t = NULL; list_for_each_entry(qe, head, node) if (qe->q == q) { t = qe->type; break; } if (!t) return; list_del(&qe->node); kfree(qe); mutex_lock(&q->sysfs_lock); elevator_switch_mq(q, t); mutex_unlock(&q->sysfs_lock); } static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) { struct request_queue *q; LIST_HEAD(head); int prev_nr_hw_queues; lockdep_assert_held(&set->tag_list_lock); if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids) nr_hw_queues = nr_cpu_ids; if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues) return; list_for_each_entry(q, &set->tag_list, tag_set_list) blk_mq_freeze_queue(q); /* * Switch IO scheduler to 'none', cleaning up the data associated * with the previous scheduler. We will switch back once we are done * updating the new sw to hw queue mappings. */ list_for_each_entry(q, &set->tag_list, tag_set_list) if (!blk_mq_elv_switch_none(&head, q)) goto switch_back; list_for_each_entry(q, &set->tag_list, tag_set_list) { blk_mq_debugfs_unregister_hctxs(q); blk_mq_sysfs_unregister(q); } if (blk_mq_realloc_tag_set_tags(set, set->nr_hw_queues, nr_hw_queues) < 0) goto reregister; prev_nr_hw_queues = set->nr_hw_queues; set->nr_hw_queues = nr_hw_queues; blk_mq_update_queue_map(set); fallback: list_for_each_entry(q, &set->tag_list, tag_set_list) { blk_mq_realloc_hw_ctxs(set, q); if (q->nr_hw_queues != set->nr_hw_queues) { pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n", nr_hw_queues, prev_nr_hw_queues); set->nr_hw_queues = prev_nr_hw_queues; blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); goto fallback; } blk_mq_map_swqueue(q); } reregister: list_for_each_entry(q, &set->tag_list, tag_set_list) { blk_mq_sysfs_register(q); blk_mq_debugfs_register_hctxs(q); } switch_back: list_for_each_entry(q, &set->tag_list, tag_set_list) blk_mq_elv_switch_back(&head, q); list_for_each_entry(q, &set->tag_list, tag_set_list) blk_mq_unfreeze_queue(q); } void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) { mutex_lock(&set->tag_list_lock); __blk_mq_update_nr_hw_queues(set, nr_hw_queues); mutex_unlock(&set->tag_list_lock); } EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); /* Enable polling stats and return whether they were already enabled. */ static bool blk_poll_stats_enable(struct request_queue *q) { if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS, q)) return true; blk_stat_add_callback(q, q->poll_cb); return false; } static void blk_mq_poll_stats_start(struct request_queue *q) { /* * We don't arm the callback if polling stats are not enabled or the * callback is already active. */ if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || blk_stat_is_active(q->poll_cb)) return; blk_stat_activate_msecs(q->poll_cb, 100); } static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb) { struct request_queue *q = cb->data; int bucket; for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) { if (cb->stat[bucket].nr_samples) q->poll_stat[bucket] = cb->stat[bucket]; } } static unsigned long blk_mq_poll_nsecs(struct request_queue *q, struct request *rq) { unsigned long ret = 0; int bucket; /* * If stats collection isn't on, don't sleep but turn it on for * future users */ if (!blk_poll_stats_enable(q)) return 0; /* * As an optimistic guess, use half of the mean service time * for this type of request. We can (and should) make this smarter. * For instance, if the completion latencies are tight, we can * get closer than just half the mean. This is especially * important on devices where the completion latencies are longer * than ~10 usec. We do use the stats for the relevant IO size * if available which does lead to better estimates. */ bucket = blk_mq_poll_stats_bkt(rq); if (bucket < 0) return ret; if (q->poll_stat[bucket].nr_samples) ret = (q->poll_stat[bucket].mean + 1) / 2; return ret; } static bool blk_mq_poll_hybrid_sleep(struct request_queue *q, struct request *rq) { struct hrtimer_sleeper hs; enum hrtimer_mode mode; unsigned int nsecs; ktime_t kt; if (rq->rq_flags & RQF_MQ_POLL_SLEPT) return false; /* * If we get here, hybrid polling is enabled. Hence poll_nsec can be: * * 0: use half of prev avg * >0: use this specific value */ if (q->poll_nsec > 0) nsecs = q->poll_nsec; else nsecs = blk_mq_poll_nsecs(q, rq); if (!nsecs) return false; rq->rq_flags |= RQF_MQ_POLL_SLEPT; /* * This will be replaced with the stats tracking code, using * 'avg_completion_time / 2' as the pre-sleep target. */ kt = nsecs; mode = HRTIMER_MODE_REL; hrtimer_init_sleeper_on_stack(&hs, CLOCK_MONOTONIC, mode); hrtimer_set_expires(&hs.timer, kt); do { if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE) break; set_current_state(TASK_UNINTERRUPTIBLE); hrtimer_sleeper_start_expires(&hs, mode); if (hs.task) io_schedule(); hrtimer_cancel(&hs.timer); mode = HRTIMER_MODE_ABS; } while (hs.task && !signal_pending(current)); __set_current_state(TASK_RUNNING); destroy_hrtimer_on_stack(&hs.timer); return true; } static bool blk_mq_poll_hybrid(struct request_queue *q, struct blk_mq_hw_ctx *hctx, blk_qc_t cookie) { struct request *rq; if (q->poll_nsec == BLK_MQ_POLL_CLASSIC) return false; if (!blk_qc_t_is_internal(cookie)) rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie)); else { rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie)); /* * With scheduling, if the request has completed, we'll * get a NULL return here, as we clear the sched tag when * that happens. The request still remains valid, like always, * so we should be safe with just the NULL check. */ if (!rq) return false; } return blk_mq_poll_hybrid_sleep(q, rq); } /** * blk_poll - poll for IO completions * @q: the queue * @cookie: cookie passed back at IO submission time * @spin: whether to spin for completions * * Description: * Poll for completions on the passed in queue. Returns number of * completed entries found. If @spin is true, then blk_poll will continue * looping until at least one completion is found, unless the task is * otherwise marked running (or we need to reschedule). */ int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) { struct blk_mq_hw_ctx *hctx; long state; if (!blk_qc_t_valid(cookie) || !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) return 0; if (current->plug) blk_flush_plug_list(current->plug, false); hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; /* * If we sleep, have the caller restart the poll loop to reset * the state. Like for the other success return cases, the * caller is responsible for checking if the IO completed. If * the IO isn't complete, we'll get called again and will go * straight to the busy poll loop. */ if (blk_mq_poll_hybrid(q, hctx, cookie)) return 1; hctx->poll_considered++; state = current->state; do { int ret; hctx->poll_invoked++; ret = q->mq_ops->poll(hctx); if (ret > 0) { hctx->poll_success++; __set_current_state(TASK_RUNNING); return ret; } if (signal_pending_state(state, current)) __set_current_state(TASK_RUNNING); if (current->state == TASK_RUNNING) return 1; if (ret < 0 || !spin) break; cpu_relax(); } while (!need_resched()); __set_current_state(TASK_RUNNING); return 0; } EXPORT_SYMBOL_GPL(blk_poll); unsigned int blk_mq_rq_cpu(struct request *rq) { return rq->mq_ctx->cpu; } EXPORT_SYMBOL(blk_mq_rq_cpu); static int __init blk_mq_init(void) { cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, blk_mq_hctx_notify_dead); return 0; } subsys_initcall(blk_mq_init);
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