| // 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/blk-integrity.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/interrupt.h> |
| #include <linux/llist.h> |
| #include <linux/cpu.h> |
| #include <linux/cache.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 <linux/blk-crypto.h> |
| #include <linux/part_stat.h> |
| #include <linux/sched/isolation.h> |
| |
| #include <trace/events/block.h> |
| |
| #include <linux/t10-pi.h> |
| #include "blk.h" |
| #include "blk-mq.h" |
| #include "blk-mq-debugfs.h" |
| #include "blk-pm.h" |
| #include "blk-stat.h" |
| #include "blk-mq-sched.h" |
| #include "blk-rq-qos.h" |
| |
| static DEFINE_PER_CPU(struct llist_head, blk_cpu_done); |
| static DEFINE_PER_CPU(call_single_data_t, blk_cpu_csd); |
| |
| static void blk_mq_insert_request(struct request *rq, blk_insert_t flags); |
| static void blk_mq_request_bypass_insert(struct request *rq, |
| blk_insert_t flags); |
| static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, |
| struct list_head *list); |
| static int blk_hctx_poll(struct request_queue *q, struct blk_mq_hw_ctx *hctx, |
| struct io_comp_batch *iob, unsigned int flags); |
| |
| /* |
| * 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 block_device *part; |
| unsigned int inflight[2]; |
| }; |
| |
| static bool blk_mq_check_inflight(struct request *rq, void *priv) |
| { |
| struct mq_inflight *mi = priv; |
| |
| if (rq->part && blk_do_io_stat(rq) && |
| (!bdev_is_partition(mi->part) || rq->part == mi->part) && |
| blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT) |
| mi->inflight[rq_data_dir(rq)]++; |
| |
| return true; |
| } |
| |
| unsigned int blk_mq_in_flight(struct request_queue *q, |
| struct block_device *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 block_device *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, bool force_atomic) |
| { |
| mutex_lock(&q->mq_freeze_lock); |
| if (force_atomic) |
| q->q_usage_counter.data->force_atomic = true; |
| 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); |
| } |
| |
| void blk_mq_unfreeze_queue(struct request_queue *q) |
| { |
| __blk_mq_unfreeze_queue(q, false); |
| } |
| 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) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&q->queue_lock, flags); |
| if (!q->quiesce_depth++) |
| blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); |
| spin_unlock_irqrestore(&q->queue_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); |
| |
| /** |
| * blk_mq_wait_quiesce_done() - wait until in-progress quiesce is done |
| * @set: tag_set to wait on |
| * |
| * Note: it is driver's responsibility for making sure that quiesce has |
| * been started on or more of the request_queues of the tag_set. This |
| * function only waits for the quiesce on those request_queues that had |
| * the quiesce flag set using blk_mq_quiesce_queue_nowait. |
| */ |
| void blk_mq_wait_quiesce_done(struct blk_mq_tag_set *set) |
| { |
| if (set->flags & BLK_MQ_F_BLOCKING) |
| synchronize_srcu(set->srcu); |
| else |
| synchronize_rcu(); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_wait_quiesce_done); |
| |
| /** |
| * 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) |
| { |
| blk_mq_quiesce_queue_nowait(q); |
| /* nothing to wait for non-mq queues */ |
| if (queue_is_mq(q)) |
| blk_mq_wait_quiesce_done(q->tag_set); |
| } |
| 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) |
| { |
| unsigned long flags; |
| bool run_queue = false; |
| |
| spin_lock_irqsave(&q->queue_lock, flags); |
| if (WARN_ON_ONCE(q->quiesce_depth <= 0)) { |
| ; |
| } else if (!--q->quiesce_depth) { |
| blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); |
| run_queue = true; |
| } |
| spin_unlock_irqrestore(&q->queue_lock, flags); |
| |
| /* dispatch requests which are inserted during quiescing */ |
| if (run_queue) |
| blk_mq_run_hw_queues(q, true); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); |
| |
| void blk_mq_quiesce_tagset(struct blk_mq_tag_set *set) |
| { |
| struct request_queue *q; |
| |
| mutex_lock(&set->tag_list_lock); |
| list_for_each_entry(q, &set->tag_list, tag_set_list) { |
| if (!blk_queue_skip_tagset_quiesce(q)) |
| blk_mq_quiesce_queue_nowait(q); |
| } |
| blk_mq_wait_quiesce_done(set); |
| mutex_unlock(&set->tag_list_lock); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_quiesce_tagset); |
| |
| void blk_mq_unquiesce_tagset(struct blk_mq_tag_set *set) |
| { |
| struct request_queue *q; |
| |
| mutex_lock(&set->tag_list_lock); |
| list_for_each_entry(q, &set->tag_list, tag_set_list) { |
| if (!blk_queue_skip_tagset_quiesce(q)) |
| blk_mq_unquiesce_queue(q); |
| } |
| mutex_unlock(&set->tag_list_lock); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_unquiesce_tagset); |
| |
| void blk_mq_wake_waiters(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned long i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| if (blk_mq_hw_queue_mapped(hctx)) |
| blk_mq_tag_wakeup_all(hctx->tags, true); |
| } |
| |
| void blk_rq_init(struct request_queue *q, struct request *rq) |
| { |
| memset(rq, 0, sizeof(*rq)); |
| |
| INIT_LIST_HEAD(&rq->queuelist); |
| rq->q = q; |
| rq->__sector = (sector_t) -1; |
| INIT_HLIST_NODE(&rq->hash); |
| RB_CLEAR_NODE(&rq->rb_node); |
| rq->tag = BLK_MQ_NO_TAG; |
| rq->internal_tag = BLK_MQ_NO_TAG; |
| rq->start_time_ns = blk_time_get_ns(); |
| rq->part = NULL; |
| blk_crypto_rq_set_defaults(rq); |
| } |
| EXPORT_SYMBOL(blk_rq_init); |
| |
| /* Set start and alloc time when the allocated request is actually used */ |
| static inline void blk_mq_rq_time_init(struct request *rq, u64 alloc_time_ns) |
| { |
| if (blk_mq_need_time_stamp(rq)) |
| rq->start_time_ns = blk_time_get_ns(); |
| else |
| rq->start_time_ns = 0; |
| |
| #ifdef CONFIG_BLK_RQ_ALLOC_TIME |
| if (blk_queue_rq_alloc_time(rq->q)) |
| rq->alloc_time_ns = alloc_time_ns ?: rq->start_time_ns; |
| else |
| rq->alloc_time_ns = 0; |
| #endif |
| } |
| |
| static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, |
| struct blk_mq_tags *tags, unsigned int tag) |
| { |
| struct blk_mq_ctx *ctx = data->ctx; |
| struct blk_mq_hw_ctx *hctx = data->hctx; |
| struct request_queue *q = data->q; |
| struct request *rq = tags->static_rqs[tag]; |
| |
| rq->q = q; |
| rq->mq_ctx = ctx; |
| rq->mq_hctx = hctx; |
| rq->cmd_flags = data->cmd_flags; |
| |
| if (data->flags & BLK_MQ_REQ_PM) |
| data->rq_flags |= RQF_PM; |
| if (blk_queue_io_stat(q)) |
| data->rq_flags |= RQF_IO_STAT; |
| rq->rq_flags = data->rq_flags; |
| |
| if (data->rq_flags & RQF_SCHED_TAGS) { |
| rq->tag = BLK_MQ_NO_TAG; |
| rq->internal_tag = tag; |
| } else { |
| rq->tag = tag; |
| rq->internal_tag = BLK_MQ_NO_TAG; |
| } |
| rq->timeout = 0; |
| |
| rq->part = NULL; |
| 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 |
| rq->end_io = NULL; |
| rq->end_io_data = NULL; |
| |
| blk_crypto_rq_set_defaults(rq); |
| INIT_LIST_HEAD(&rq->queuelist); |
| /* tag was already set */ |
| WRITE_ONCE(rq->deadline, 0); |
| req_ref_set(rq, 1); |
| |
| if (rq->rq_flags & RQF_USE_SCHED) { |
| struct elevator_queue *e = data->q->elevator; |
| |
| INIT_HLIST_NODE(&rq->hash); |
| RB_CLEAR_NODE(&rq->rb_node); |
| |
| if (e->type->ops.prepare_request) |
| e->type->ops.prepare_request(rq); |
| } |
| |
| return rq; |
| } |
| |
| static inline struct request * |
| __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data) |
| { |
| unsigned int tag, tag_offset; |
| struct blk_mq_tags *tags; |
| struct request *rq; |
| unsigned long tag_mask; |
| int i, nr = 0; |
| |
| tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset); |
| if (unlikely(!tag_mask)) |
| return NULL; |
| |
| tags = blk_mq_tags_from_data(data); |
| for (i = 0; tag_mask; i++) { |
| if (!(tag_mask & (1UL << i))) |
| continue; |
| tag = tag_offset + i; |
| prefetch(tags->static_rqs[tag]); |
| tag_mask &= ~(1UL << i); |
| rq = blk_mq_rq_ctx_init(data, tags, tag); |
| rq_list_add(data->cached_rq, rq); |
| nr++; |
| } |
| if (!(data->rq_flags & RQF_SCHED_TAGS)) |
| blk_mq_add_active_requests(data->hctx, nr); |
| /* caller already holds a reference, add for remainder */ |
| percpu_ref_get_many(&data->q->q_usage_counter, nr - 1); |
| data->nr_tags -= nr; |
| |
| return rq_list_pop(data->cached_rq); |
| } |
| |
| static struct request *__blk_mq_alloc_requests(struct blk_mq_alloc_data *data) |
| { |
| struct request_queue *q = data->q; |
| u64 alloc_time_ns = 0; |
| struct request *rq; |
| unsigned int tag; |
| |
| /* alloc_time includes depth and tag waits */ |
| if (blk_queue_rq_alloc_time(q)) |
| alloc_time_ns = blk_time_get_ns(); |
| |
| if (data->cmd_flags & REQ_NOWAIT) |
| data->flags |= BLK_MQ_REQ_NOWAIT; |
| |
| retry: |
| data->ctx = blk_mq_get_ctx(q); |
| data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx); |
| |
| if (q->elevator) { |
| /* |
| * All requests use scheduler tags when an I/O scheduler is |
| * enabled for the queue. |
| */ |
| data->rq_flags |= RQF_SCHED_TAGS; |
| |
| /* |
| * Flush/passthrough requests are special and go directly to the |
| * dispatch list. |
| */ |
| if ((data->cmd_flags & REQ_OP_MASK) != REQ_OP_FLUSH && |
| !blk_op_is_passthrough(data->cmd_flags)) { |
| struct elevator_mq_ops *ops = &q->elevator->type->ops; |
| |
| WARN_ON_ONCE(data->flags & BLK_MQ_REQ_RESERVED); |
| |
| data->rq_flags |= RQF_USE_SCHED; |
| if (ops->limit_depth) |
| ops->limit_depth(data->cmd_flags, data); |
| } |
| } else { |
| blk_mq_tag_busy(data->hctx); |
| } |
| |
| if (data->flags & BLK_MQ_REQ_RESERVED) |
| data->rq_flags |= RQF_RESV; |
| |
| /* |
| * Try batched alloc if we want more than 1 tag. |
| */ |
| if (data->nr_tags > 1) { |
| rq = __blk_mq_alloc_requests_batch(data); |
| if (rq) { |
| blk_mq_rq_time_init(rq, alloc_time_ns); |
| return rq; |
| } |
| data->nr_tags = 1; |
| } |
| |
| /* |
| * Waiting allocations only fail because of an inactive hctx. In that |
| * case just retry the hctx assignment and tag allocation as CPU hotplug |
| * should have migrated us to an online CPU by now. |
| */ |
| tag = blk_mq_get_tag(data); |
| if (tag == BLK_MQ_NO_TAG) { |
| if (data->flags & BLK_MQ_REQ_NOWAIT) |
| return NULL; |
| /* |
| * Give up the CPU and sleep for a random short time to |
| * ensure that thread using a realtime scheduling class |
| * are migrated off the CPU, and thus off the hctx that |
| * is going away. |
| */ |
| msleep(3); |
| goto retry; |
| } |
| |
| if (!(data->rq_flags & RQF_SCHED_TAGS)) |
| blk_mq_inc_active_requests(data->hctx); |
| rq = blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag); |
| blk_mq_rq_time_init(rq, alloc_time_ns); |
| return rq; |
| } |
| |
| static struct request *blk_mq_rq_cache_fill(struct request_queue *q, |
| struct blk_plug *plug, |
| blk_opf_t opf, |
| blk_mq_req_flags_t flags) |
| { |
| struct blk_mq_alloc_data data = { |
| .q = q, |
| .flags = flags, |
| .cmd_flags = opf, |
| .nr_tags = plug->nr_ios, |
| .cached_rq = &plug->cached_rq, |
| }; |
| struct request *rq; |
| |
| if (blk_queue_enter(q, flags)) |
| return NULL; |
| |
| plug->nr_ios = 1; |
| |
| rq = __blk_mq_alloc_requests(&data); |
| if (unlikely(!rq)) |
| blk_queue_exit(q); |
| return rq; |
| } |
| |
| static struct request *blk_mq_alloc_cached_request(struct request_queue *q, |
| blk_opf_t opf, |
| blk_mq_req_flags_t flags) |
| { |
| struct blk_plug *plug = current->plug; |
| struct request *rq; |
| |
| if (!plug) |
| return NULL; |
| |
| if (rq_list_empty(plug->cached_rq)) { |
| if (plug->nr_ios == 1) |
| return NULL; |
| rq = blk_mq_rq_cache_fill(q, plug, opf, flags); |
| if (!rq) |
| return NULL; |
| } else { |
| rq = rq_list_peek(&plug->cached_rq); |
| if (!rq || rq->q != q) |
| return NULL; |
| |
| if (blk_mq_get_hctx_type(opf) != rq->mq_hctx->type) |
| return NULL; |
| if (op_is_flush(rq->cmd_flags) != op_is_flush(opf)) |
| return NULL; |
| |
| plug->cached_rq = rq_list_next(rq); |
| blk_mq_rq_time_init(rq, 0); |
| } |
| |
| rq->cmd_flags = opf; |
| INIT_LIST_HEAD(&rq->queuelist); |
| return rq; |
| } |
| |
| struct request *blk_mq_alloc_request(struct request_queue *q, blk_opf_t opf, |
| blk_mq_req_flags_t flags) |
| { |
| struct request *rq; |
| |
| rq = blk_mq_alloc_cached_request(q, opf, flags); |
| if (!rq) { |
| struct blk_mq_alloc_data data = { |
| .q = q, |
| .flags = flags, |
| .cmd_flags = opf, |
| .nr_tags = 1, |
| }; |
| int ret; |
| |
| ret = blk_queue_enter(q, flags); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| rq = __blk_mq_alloc_requests(&data); |
| if (!rq) |
| goto out_queue_exit; |
| } |
| rq->__data_len = 0; |
| rq->__sector = (sector_t) -1; |
| rq->bio = rq->biotail = NULL; |
| return rq; |
| out_queue_exit: |
| blk_queue_exit(q); |
| return ERR_PTR(-EWOULDBLOCK); |
| } |
| EXPORT_SYMBOL(blk_mq_alloc_request); |
| |
| struct request *blk_mq_alloc_request_hctx(struct request_queue *q, |
| blk_opf_t opf, blk_mq_req_flags_t flags, unsigned int hctx_idx) |
| { |
| struct blk_mq_alloc_data data = { |
| .q = q, |
| .flags = flags, |
| .cmd_flags = opf, |
| .nr_tags = 1, |
| }; |
| u64 alloc_time_ns = 0; |
| struct request *rq; |
| unsigned int cpu; |
| unsigned int tag; |
| int ret; |
| |
| /* alloc_time includes depth and tag waits */ |
| if (blk_queue_rq_alloc_time(q)) |
| alloc_time_ns = blk_time_get_ns(); |
| |
| /* |
| * 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)) || |
| WARN_ON_ONCE(!(flags & BLK_MQ_REQ_RESERVED))) |
| 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. |
| */ |
| ret = -EXDEV; |
| data.hctx = xa_load(&q->hctx_table, hctx_idx); |
| if (!blk_mq_hw_queue_mapped(data.hctx)) |
| goto out_queue_exit; |
| cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask); |
| if (cpu >= nr_cpu_ids) |
| goto out_queue_exit; |
| data.ctx = __blk_mq_get_ctx(q, cpu); |
| |
| if (q->elevator) |
| data.rq_flags |= RQF_SCHED_TAGS; |
| else |
| blk_mq_tag_busy(data.hctx); |
| |
| if (flags & BLK_MQ_REQ_RESERVED) |
| data.rq_flags |= RQF_RESV; |
| |
| ret = -EWOULDBLOCK; |
| tag = blk_mq_get_tag(&data); |
| if (tag == BLK_MQ_NO_TAG) |
| goto out_queue_exit; |
| if (!(data.rq_flags & RQF_SCHED_TAGS)) |
| blk_mq_inc_active_requests(data.hctx); |
| rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag); |
| blk_mq_rq_time_init(rq, alloc_time_ns); |
| rq->__data_len = 0; |
| rq->__sector = (sector_t) -1; |
| rq->bio = rq->biotail = NULL; |
| return rq; |
| |
| out_queue_exit: |
| blk_queue_exit(q); |
| return ERR_PTR(ret); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx); |
| |
| static void blk_mq_finish_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| blk_zone_finish_request(rq); |
| |
| if (rq->rq_flags & RQF_USE_SCHED) { |
| q->elevator->type->ops.finish_request(rq); |
| /* |
| * For postflush request that may need to be |
| * completed twice, we should clear this flag |
| * to avoid double finish_request() on the rq. |
| */ |
| rq->rq_flags &= ~RQF_USE_SCHED; |
| } |
| } |
| |
| 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_crypto_free_request(rq); |
| blk_pm_mark_last_busy(rq); |
| rq->mq_hctx = NULL; |
| |
| if (rq->tag != BLK_MQ_NO_TAG) { |
| blk_mq_dec_active_requests(hctx); |
| blk_mq_put_tag(hctx->tags, ctx, rq->tag); |
| } |
| if (sched_tag != BLK_MQ_NO_TAG) |
| 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; |
| |
| blk_mq_finish_request(rq); |
| |
| if (unlikely(laptop_mode && !blk_rq_is_passthrough(rq))) |
| laptop_io_completion(q->disk->bdi); |
| |
| rq_qos_done(q, rq); |
| |
| WRITE_ONCE(rq->state, MQ_RQ_IDLE); |
| if (req_ref_put_and_test(rq)) |
| __blk_mq_free_request(rq); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_free_request); |
| |
| void blk_mq_free_plug_rqs(struct blk_plug *plug) |
| { |
| struct request *rq; |
| |
| while ((rq = rq_list_pop(&plug->cached_rq)) != NULL) |
| blk_mq_free_request(rq); |
| } |
| |
| void blk_dump_rq_flags(struct request *rq, char *msg) |
| { |
| printk(KERN_INFO "%s: dev %s: flags=%llx\n", msg, |
| rq->q->disk ? rq->q->disk->disk_name : "?", |
| (__force 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_account_io_completion(struct request *req, unsigned int bytes) |
| { |
| if (req->part && blk_do_io_stat(req)) { |
| const int sgrp = op_stat_group(req_op(req)); |
| |
| part_stat_lock(); |
| part_stat_add(req->part, sectors[sgrp], bytes >> 9); |
| part_stat_unlock(); |
| } |
| } |
| |
| static void blk_print_req_error(struct request *req, blk_status_t status) |
| { |
| printk_ratelimited(KERN_ERR |
| "%s error, dev %s, sector %llu op 0x%x:(%s) flags 0x%x " |
| "phys_seg %u prio class %u\n", |
| blk_status_to_str(status), |
| req->q->disk ? req->q->disk->disk_name : "?", |
| blk_rq_pos(req), (__force u32)req_op(req), |
| blk_op_str(req_op(req)), |
| (__force u32)(req->cmd_flags & ~REQ_OP_MASK), |
| req->nr_phys_segments, |
| IOPRIO_PRIO_CLASS(req->ioprio)); |
| } |
| |
| /* |
| * Fully end IO on a request. Does not support partial completions, or |
| * errors. |
| */ |
| static void blk_complete_request(struct request *req) |
| { |
| const bool is_flush = (req->rq_flags & RQF_FLUSH_SEQ) != 0; |
| int total_bytes = blk_rq_bytes(req); |
| struct bio *bio = req->bio; |
| |
| trace_block_rq_complete(req, BLK_STS_OK, total_bytes); |
| |
| if (!bio) |
| return; |
| |
| if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ) |
| blk_integrity_complete(req, total_bytes); |
| |
| /* |
| * Upper layers may call blk_crypto_evict_key() anytime after the last |
| * bio_endio(). Therefore, the keyslot must be released before that. |
| */ |
| blk_crypto_rq_put_keyslot(req); |
| |
| blk_account_io_completion(req, total_bytes); |
| |
| do { |
| struct bio *next = bio->bi_next; |
| |
| /* Completion has already been traced */ |
| bio_clear_flag(bio, BIO_TRACE_COMPLETION); |
| |
| blk_zone_update_request_bio(req, bio); |
| |
| if (!is_flush) |
| bio_endio(bio); |
| bio = next; |
| } while (bio); |
| |
| /* |
| * Reset counters so that the request stacking driver |
| * can find how many bytes remain in the request |
| * later. |
| */ |
| if (!req->end_io) { |
| req->bio = NULL; |
| req->__data_len = 0; |
| } |
| } |
| |
| /** |
| * blk_update_request - Complete multiple bytes without completing the request |
| * @req: the request being processed |
| * @error: block status code |
| * @nr_bytes: number of bytes to complete for @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. |
| * |
| * 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 this function |
| * except in the consistency check at the end of this function. |
| * |
| * 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) |
| { |
| bool is_flush = req->rq_flags & RQF_FLUSH_SEQ; |
| bool quiet = req->rq_flags & RQF_QUIET; |
| int total_bytes; |
| |
| trace_block_rq_complete(req, error, nr_bytes); |
| |
| if (!req->bio) |
| return false; |
| |
| if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ && |
| error == BLK_STS_OK) |
| blk_integrity_complete(req, nr_bytes); |
| |
| /* |
| * Upper layers may call blk_crypto_evict_key() anytime after the last |
| * bio_endio(). Therefore, the keyslot must be released before that. |
| */ |
| if (blk_crypto_rq_has_keyslot(req) && nr_bytes >= blk_rq_bytes(req)) |
| __blk_crypto_rq_put_keyslot(req); |
| |
| if (unlikely(error && !blk_rq_is_passthrough(req) && !quiet) && |
| !test_bit(GD_DEAD, &req->q->disk->state)) { |
| blk_print_req_error(req, error); |
| trace_block_rq_error(req, error, nr_bytes); |
| } |
| |
| 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 (unlikely(error)) |
| bio->bi_status = error; |
| |
| if (bio_bytes == bio->bi_iter.bi_size) { |
| req->bio = bio->bi_next; |
| } else if (bio_is_zone_append(bio) && error == BLK_STS_OK) { |
| /* |
| * Partial zone append completions cannot be supported |
| * as the BIO fragments may end up not being written |
| * sequentially. |
| */ |
| bio->bi_status = BLK_STS_IOERR; |
| } |
| |
| /* Completion has already been traced */ |
| bio_clear_flag(bio, BIO_TRACE_COMPLETION); |
| if (unlikely(quiet)) |
| bio_set_flag(bio, BIO_QUIET); |
| |
| bio_advance(bio, bio_bytes); |
| |
| /* Don't actually finish bio if it's part of flush sequence */ |
| if (!bio->bi_iter.bi_size) { |
| blk_zone_update_request_bio(req, bio); |
| if (!is_flush) |
| bio_endio(bio); |
| } |
| |
| total_bytes += bio_bytes; |
| nr_bytes -= bio_bytes; |
| |
| if (!nr_bytes) |
| break; |
| } |
| |
| /* |
| * completely done |
| */ |
| if (!req->bio) { |
| /* |
| * Reset counters so that the request stacking driver |
| * can find how many bytes remain in the request |
| * later. |
| */ |
| req->__data_len = 0; |
| return false; |
| } |
| |
| req->__data_len -= total_bytes; |
| |
| /* update sector only for requests with clear definition of sector */ |
| if (!blk_rq_is_passthrough(req)) |
| req->__sector += total_bytes >> 9; |
| |
| /* mixed attributes always follow the first bio */ |
| if (req->rq_flags & RQF_MIXED_MERGE) { |
| req->cmd_flags &= ~REQ_FAILFAST_MASK; |
| req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; |
| } |
| |
| if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { |
| /* |
| * If total number of sectors is less than the first segment |
| * size, something has gone terribly wrong. |
| */ |
| if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { |
| blk_dump_rq_flags(req, "request botched"); |
| req->__data_len = blk_rq_cur_bytes(req); |
| } |
| |
| /* recalculate the number of segments */ |
| req->nr_phys_segments = blk_recalc_rq_segments(req); |
| } |
| |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(blk_update_request); |
| |
| static inline void blk_account_io_done(struct request *req, u64 now) |
| { |
| trace_block_io_done(req); |
| |
| /* |
| * 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->part && |
| !(req->rq_flags & RQF_FLUSH_SEQ)) { |
| const int sgrp = op_stat_group(req_op(req)); |
| |
| part_stat_lock(); |
| update_io_ticks(req->part, jiffies, true); |
| part_stat_inc(req->part, ios[sgrp]); |
| part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns); |
| part_stat_local_dec(req->part, |
| in_flight[op_is_write(req_op(req))]); |
| part_stat_unlock(); |
| } |
| } |
| |
| static inline void blk_account_io_start(struct request *req) |
| { |
| trace_block_io_start(req); |
| |
| if (blk_do_io_stat(req)) { |
| /* |
| * All non-passthrough requests are created from a bio with one |
| * exception: when a flush command that is part of a flush sequence |
| * generated by the state machine in blk-flush.c is cloned onto the |
| * lower device by dm-multipath we can get here without a bio. |
| */ |
| if (req->bio) |
| req->part = req->bio->bi_bdev; |
| else |
| req->part = req->q->disk->part0; |
| |
| part_stat_lock(); |
| update_io_ticks(req->part, jiffies, false); |
| part_stat_local_inc(req->part, |
| in_flight[op_is_write(req_op(req))]); |
| part_stat_unlock(); |
| } |
| } |
| |
| static inline void __blk_mq_end_request_acct(struct request *rq, u64 now) |
| { |
| if (rq->rq_flags & RQF_STATS) |
| blk_stat_add(rq, now); |
| |
| blk_mq_sched_completed_request(rq, now); |
| blk_account_io_done(rq, now); |
| } |
| |
| inline void __blk_mq_end_request(struct request *rq, blk_status_t error) |
| { |
| if (blk_mq_need_time_stamp(rq)) |
| __blk_mq_end_request_acct(rq, blk_time_get_ns()); |
| |
| blk_mq_finish_request(rq); |
| |
| if (rq->end_io) { |
| rq_qos_done(rq->q, rq); |
| if (rq->end_io(rq, error) == RQ_END_IO_FREE) |
| blk_mq_free_request(rq); |
| } 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); |
| |
| #define TAG_COMP_BATCH 32 |
| |
| static inline void blk_mq_flush_tag_batch(struct blk_mq_hw_ctx *hctx, |
| int *tag_array, int nr_tags) |
| { |
| struct request_queue *q = hctx->queue; |
| |
| blk_mq_sub_active_requests(hctx, nr_tags); |
| |
| blk_mq_put_tags(hctx->tags, tag_array, nr_tags); |
| percpu_ref_put_many(&q->q_usage_counter, nr_tags); |
| } |
| |
| void blk_mq_end_request_batch(struct io_comp_batch *iob) |
| { |
| int tags[TAG_COMP_BATCH], nr_tags = 0; |
| struct blk_mq_hw_ctx *cur_hctx = NULL; |
| struct request *rq; |
| u64 now = 0; |
| |
| if (iob->need_ts) |
| now = blk_time_get_ns(); |
| |
| while ((rq = rq_list_pop(&iob->req_list)) != NULL) { |
| prefetch(rq->bio); |
| prefetch(rq->rq_next); |
| |
| blk_complete_request(rq); |
| if (iob->need_ts) |
| __blk_mq_end_request_acct(rq, now); |
| |
| blk_mq_finish_request(rq); |
| |
| rq_qos_done(rq->q, rq); |
| |
| /* |
| * If end_io handler returns NONE, then it still has |
| * ownership of the request. |
| */ |
| if (rq->end_io && rq->end_io(rq, 0) == RQ_END_IO_NONE) |
| continue; |
| |
| WRITE_ONCE(rq->state, MQ_RQ_IDLE); |
| if (!req_ref_put_and_test(rq)) |
| continue; |
| |
| blk_crypto_free_request(rq); |
| blk_pm_mark_last_busy(rq); |
| |
| if (nr_tags == TAG_COMP_BATCH || cur_hctx != rq->mq_hctx) { |
| if (cur_hctx) |
| blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags); |
| nr_tags = 0; |
| cur_hctx = rq->mq_hctx; |
| } |
| tags[nr_tags++] = rq->tag; |
| } |
| |
| if (nr_tags) |
| blk_mq_flush_tag_batch(cur_hctx, tags, nr_tags); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_end_request_batch); |
| |
| static void blk_complete_reqs(struct llist_head *list) |
| { |
| struct llist_node *entry = llist_reverse_order(llist_del_all(list)); |
| struct request *rq, *next; |
| |
| llist_for_each_entry_safe(rq, next, entry, ipi_list) |
| rq->q->mq_ops->complete(rq); |
| } |
| |
| static __latent_entropy void blk_done_softirq(struct softirq_action *h) |
| { |
| blk_complete_reqs(this_cpu_ptr(&blk_cpu_done)); |
| } |
| |
| static int blk_softirq_cpu_dead(unsigned int cpu) |
| { |
| blk_complete_reqs(&per_cpu(blk_cpu_done, cpu)); |
| return 0; |
| } |
| |
| static void __blk_mq_complete_request_remote(void *data) |
| { |
| __raise_softirq_irqoff(BLOCK_SOFTIRQ); |
| } |
| |
| static inline bool blk_mq_complete_need_ipi(struct request *rq) |
| { |
| int cpu = raw_smp_processor_id(); |
| |
| if (!IS_ENABLED(CONFIG_SMP) || |
| !test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) |
| return false; |
| /* |
| * With force threaded interrupts enabled, raising softirq from an SMP |
| * function call will always result in waking the ksoftirqd thread. |
| * This is probably worse than completing the request on a different |
| * cache domain. |
| */ |
| if (force_irqthreads()) |
| return false; |
| |
| /* same CPU or cache domain and capacity? Complete locally */ |
| if (cpu == rq->mq_ctx->cpu || |
| (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) && |
| cpus_share_cache(cpu, rq->mq_ctx->cpu) && |
| cpus_equal_capacity(cpu, rq->mq_ctx->cpu))) |
| return false; |
| |
| /* don't try to IPI to an offline CPU */ |
| return cpu_online(rq->mq_ctx->cpu); |
| } |
| |
| static void blk_mq_complete_send_ipi(struct request *rq) |
| { |
| unsigned int cpu; |
| |
| cpu = rq->mq_ctx->cpu; |
| if (llist_add(&rq->ipi_list, &per_cpu(blk_cpu_done, cpu))) |
| smp_call_function_single_async(cpu, &per_cpu(blk_cpu_csd, cpu)); |
| } |
| |
| static void blk_mq_raise_softirq(struct request *rq) |
| { |
| struct llist_head *list; |
| |
| preempt_disable(); |
| list = this_cpu_ptr(&blk_cpu_done); |
| if (llist_add(&rq->ipi_list, list)) |
| raise_softirq(BLOCK_SOFTIRQ); |
| preempt_enable(); |
| } |
| |
| bool blk_mq_complete_request_remote(struct request *rq) |
| { |
| WRITE_ONCE(rq->state, MQ_RQ_COMPLETE); |
| |
| /* |
| * For request which hctx has only one ctx mapping, |
| * or a polled request, always complete locally, |
| * it's pointless to redirect the completion. |
| */ |
| if ((rq->mq_hctx->nr_ctx == 1 && |
| rq->mq_ctx->cpu == raw_smp_processor_id()) || |
| rq->cmd_flags & REQ_POLLED) |
| return false; |
| |
| if (blk_mq_complete_need_ipi(rq)) { |
| blk_mq_complete_send_ipi(rq); |
| return true; |
| } |
| |
| if (rq->q->nr_hw_queues == 1) { |
| blk_mq_raise_softirq(rq); |
| return true; |
| } |
| return false; |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_complete_request_remote); |
| |
| /** |
| * blk_mq_complete_request - end I/O on a request |
| * @rq: the request being processed |
| * |
| * Description: |
| * Complete a request by scheduling the ->complete_rq operation. |
| **/ |
| void blk_mq_complete_request(struct request *rq) |
| { |
| if (!blk_mq_complete_request_remote(rq)) |
| rq->q->mq_ops->complete(rq); |
| } |
| 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(rq); |
| |
| if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags) && |
| !blk_rq_is_passthrough(rq)) { |
| rq->io_start_time_ns = blk_time_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); |
| rq->mq_hctx->tags->rqs[rq->tag] = rq; |
| |
| if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE) |
| blk_integrity_prepare(rq); |
| |
| if (rq->bio && rq->bio->bi_opf & REQ_POLLED) |
| WRITE_ONCE(rq->bio->bi_cookie, rq->mq_hctx->queue_num); |
| } |
| EXPORT_SYMBOL(blk_mq_start_request); |
| |
| /* |
| * Allow 2x BLK_MAX_REQUEST_COUNT requests on plug queue for multiple |
| * queues. This is important for md arrays to benefit from merging |
| * requests. |
| */ |
| static inline unsigned short blk_plug_max_rq_count(struct blk_plug *plug) |
| { |
| if (plug->multiple_queues) |
| return BLK_MAX_REQUEST_COUNT * 2; |
| return BLK_MAX_REQUEST_COUNT; |
| } |
| |
| static void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) |
| { |
| struct request *last = rq_list_peek(&plug->mq_list); |
| |
| if (!plug->rq_count) { |
| trace_block_plug(rq->q); |
| } else if (plug->rq_count >= blk_plug_max_rq_count(plug) || |
| (!blk_queue_nomerges(rq->q) && |
| blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { |
| blk_mq_flush_plug_list(plug, false); |
| last = NULL; |
| trace_block_plug(rq->q); |
| } |
| |
| if (!plug->multiple_queues && last && last->q != rq->q) |
| plug->multiple_queues = true; |
| /* |
| * Any request allocated from sched tags can't be issued to |
| * ->queue_rqs() directly |
| */ |
| if (!plug->has_elevator && (rq->rq_flags & RQF_SCHED_TAGS)) |
| plug->has_elevator = true; |
| rq->rq_next = NULL; |
| rq_list_add(&plug->mq_list, rq); |
| plug->rq_count++; |
| } |
| |
| /** |
| * blk_execute_rq_nowait - insert a request to I/O scheduler for execution |
| * @rq: request to insert |
| * @at_head: insert request at head or tail of queue |
| * |
| * Description: |
| * Insert a fully prepared request at the back of the I/O scheduler queue |
| * for execution. Don't wait for completion. |
| * |
| * Note: |
| * This function will invoke @done directly if the queue is dead. |
| */ |
| void blk_execute_rq_nowait(struct request *rq, bool at_head) |
| { |
| struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
| |
| WARN_ON(irqs_disabled()); |
| WARN_ON(!blk_rq_is_passthrough(rq)); |
| |
| blk_account_io_start(rq); |
| |
| if (current->plug && !at_head) { |
| blk_add_rq_to_plug(current->plug, rq); |
| return; |
| } |
| |
| blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0); |
| blk_mq_run_hw_queue(hctx, hctx->flags & BLK_MQ_F_BLOCKING); |
| } |
| EXPORT_SYMBOL_GPL(blk_execute_rq_nowait); |
| |
| struct blk_rq_wait { |
| struct completion done; |
| blk_status_t ret; |
| }; |
| |
| static enum rq_end_io_ret blk_end_sync_rq(struct request *rq, blk_status_t ret) |
| { |
| struct blk_rq_wait *wait = rq->end_io_data; |
| |
| wait->ret = ret; |
| complete(&wait->done); |
| return RQ_END_IO_NONE; |
| } |
| |
| bool blk_rq_is_poll(struct request *rq) |
| { |
| if (!rq->mq_hctx) |
| return false; |
| if (rq->mq_hctx->type != HCTX_TYPE_POLL) |
| return false; |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(blk_rq_is_poll); |
| |
| static void blk_rq_poll_completion(struct request *rq, struct completion *wait) |
| { |
| do { |
| blk_hctx_poll(rq->q, rq->mq_hctx, NULL, 0); |
| cond_resched(); |
| } while (!completion_done(wait)); |
| } |
| |
| /** |
| * blk_execute_rq - insert a request into queue for execution |
| * @rq: request to insert |
| * @at_head: insert request at head or tail of queue |
| * |
| * Description: |
| * Insert a fully prepared request at the back of the I/O scheduler queue |
| * for execution and wait for completion. |
| * Return: The blk_status_t result provided to blk_mq_end_request(). |
| */ |
| blk_status_t blk_execute_rq(struct request *rq, bool at_head) |
| { |
| struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
| struct blk_rq_wait wait = { |
| .done = COMPLETION_INITIALIZER_ONSTACK(wait.done), |
| }; |
| |
| WARN_ON(irqs_disabled()); |
| WARN_ON(!blk_rq_is_passthrough(rq)); |
| |
| rq->end_io_data = &wait; |
| rq->end_io = blk_end_sync_rq; |
| |
| blk_account_io_start(rq); |
| blk_mq_insert_request(rq, at_head ? BLK_MQ_INSERT_AT_HEAD : 0); |
| blk_mq_run_hw_queue(hctx, false); |
| |
| if (blk_rq_is_poll(rq)) |
| blk_rq_poll_completion(rq, &wait.done); |
| else |
| blk_wait_io(&wait.done); |
| |
| return wait.ret; |
| } |
| EXPORT_SYMBOL(blk_execute_rq); |
| |
| 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(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; |
| } |
| } |
| |
| void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list) |
| { |
| struct request_queue *q = rq->q; |
| unsigned long flags; |
| |
| __blk_mq_requeue_request(rq); |
| |
| /* this request will be re-inserted to io scheduler queue */ |
| blk_mq_sched_requeue_request(rq); |
| |
| spin_lock_irqsave(&q->requeue_lock, flags); |
| 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); |
| } |
| 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); |
| LIST_HEAD(flush_list); |
| struct request *rq; |
| |
| spin_lock_irq(&q->requeue_lock); |
| list_splice_init(&q->requeue_list, &rq_list); |
| list_splice_init(&q->flush_list, &flush_list); |
| spin_unlock_irq(&q->requeue_lock); |
| |
| while (!list_empty(&rq_list)) { |
| rq = list_entry(rq_list.next, struct request, queuelist); |
| /* |
| * If RQF_DONTPREP ist set, the request has been started by the |
| * driver already and might have driver-specific data allocated |
| * already. Insert it into the hctx dispatch list to avoid |
| * block layer merges for the request. |
| */ |
| if (rq->rq_flags & RQF_DONTPREP) { |
| list_del_init(&rq->queuelist); |
| blk_mq_request_bypass_insert(rq, 0); |
| } else { |
| list_del_init(&rq->queuelist); |
| blk_mq_insert_request(rq, BLK_MQ_INSERT_AT_HEAD); |
| } |
| } |
| |
| while (!list_empty(&flush_list)) { |
| rq = list_entry(flush_list.next, struct request, queuelist); |
| list_del_init(&rq->queuelist); |
| blk_mq_insert_request(rq, 0); |
| } |
| |
| blk_mq_run_hw_queues(q, false); |
| } |
| |
| 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); |
| |
| static bool blk_is_flush_data_rq(struct request *rq) |
| { |
| return (rq->rq_flags & RQF_FLUSH_SEQ) && !is_flush_rq(rq); |
| } |
| |
| static bool blk_mq_rq_inflight(struct request *rq, void *priv) |
| { |
| /* |
| * If we find a request that isn't idle we know the queue is busy |
| * as it's checked in the iter. |
| * Return false to stop the iteration. |
| * |
| * In case of queue quiesce, if one flush data request is completed, |
| * don't count it as inflight given the flush sequence is suspended, |
| * and the original flush data request is invisible to driver, just |
| * like other pending requests because of quiesce |
| */ |
| if (blk_mq_request_started(rq) && !(blk_queue_quiesced(rq->q) && |
| blk_is_flush_data_rq(rq) && |
| blk_mq_request_completed(rq))) { |
| 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) |
| { |
| 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); |
| if (ret == BLK_EH_DONE) |
| return; |
| WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER); |
| } |
| |
| blk_add_timer(req); |
| } |
| |
| struct blk_expired_data { |
| bool has_timedout_rq; |
| unsigned long next; |
| unsigned long timeout_start; |
| }; |
| |
| static bool blk_mq_req_expired(struct request *rq, struct blk_expired_data *expired) |
| { |
| 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(expired->timeout_start, deadline)) |
| return true; |
| |
| if (expired->next == 0) |
| expired->next = deadline; |
| else if (time_after(expired->next, deadline)) |
| expired->next = deadline; |
| return false; |
| } |
| |
| void blk_mq_put_rq_ref(struct request *rq) |
| { |
| if (is_flush_rq(rq)) { |
| if (rq->end_io(rq, 0) == RQ_END_IO_FREE) |
| blk_mq_free_request(rq); |
| } else if (req_ref_put_and_test(rq)) { |
| __blk_mq_free_request(rq); |
| } |
| } |
| |
| static bool blk_mq_check_expired(struct request *rq, void *priv) |
| { |
| struct blk_expired_data *expired = priv; |
| |
| /* |
| * blk_mq_queue_tag_busy_iter() has locked the request, so it cannot |
| * be reallocated underneath the timeout handler's processing, then |
| * the expire check is reliable. If the request is not expired, then |
| * it was completed and reallocated as a new request after returning |
| * from blk_mq_check_expired(). |
| */ |
| if (blk_mq_req_expired(rq, expired)) { |
| expired->has_timedout_rq = true; |
| return false; |
| } |
| return true; |
| } |
| |
| static bool blk_mq_handle_expired(struct request *rq, void *priv) |
| { |
| struct blk_expired_data *expired = priv; |
| |
| if (blk_mq_req_expired(rq, expired)) |
| blk_mq_rq_timed_out(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); |
| struct blk_expired_data expired = { |
| .timeout_start = jiffies, |
| }; |
| struct blk_mq_hw_ctx *hctx; |
| unsigned long 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; |
| |
| /* check if there is any timed-out request */ |
| blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &expired); |
| if (expired.has_timedout_rq) { |
| /* |
| * Before walking tags, we must ensure any submit started |
| * before the current time has finished. Since the submit |
| * uses srcu or rcu, wait for a synchronization point to |
| * ensure all running submits have finished |
| */ |
| blk_mq_wait_quiesce_done(q->tag_set); |
| |
| expired.next = 0; |
| blk_mq_queue_tag_busy_iter(q, blk_mq_handle_expired, &expired); |
| } |
| |
| if (expired.next != 0) { |
| mod_timer(&q->timeout, expired.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; |
| } |
| |
| bool __blk_mq_alloc_driver_tag(struct request *rq) |
| { |
| struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags; |
| unsigned int tag_offset = rq->mq_hctx->tags->nr_reserved_tags; |
| int tag; |
| |
| blk_mq_tag_busy(rq->mq_hctx); |
| |
| if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) { |
| bt = &rq->mq_hctx->tags->breserved_tags; |
| tag_offset = 0; |
| } else { |
| if (!hctx_may_queue(rq->mq_hctx, bt)) |
| return false; |
| } |
| |
| tag = __sbitmap_queue_get(bt); |
| if (tag == BLK_MQ_NO_TAG) |
| return false; |
| |
| rq->tag = tag + tag_offset; |
| blk_mq_inc_active_requests(rq->mq_hctx); |
| return true; |
| } |
| |
| 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; |
| struct wait_queue_head *wq; |
| wait_queue_entry_t *wait; |
| bool ret; |
| |
| if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) && |
| !(blk_mq_is_shared_tags(hctx->flags))) { |
| 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; |
| |
| if (blk_mq_tag_is_reserved(rq->mq_hctx->sched_tags, rq->internal_tag)) |
| sbq = &hctx->tags->breserved_tags; |
| else |
| sbq = &hctx->tags->bitmap_tags; |
| 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); |
| |
| /* |
| * Add one explicit barrier since blk_mq_get_driver_tag() may |
| * not imply barrier in case of failure. |
| * |
| * Order adding us to wait queue and allocating driver tag. |
| * |
| * The pair is the one implied in sbitmap_queue_wake_up() which |
| * orders clearing sbitmap tag bits and waitqueue_active() in |
| * __sbitmap_queue_wake_up(), since waitqueue_active() is lockless |
| * |
| * Otherwise, re-order of adding wait queue and getting driver tag |
| * may cause __sbitmap_queue_wake_up() to wake up nothing because |
| * the waitqueue_active() may not observe us in wait queue. |
| */ |
| smp_mb(); |
| |
| /* |
| * 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; |
| |
| 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) |
| { |
| list_add(&rq->queuelist, list); |
| __blk_mq_requeue_request(rq); |
| } |
| |
| enum prep_dispatch { |
| PREP_DISPATCH_OK, |
| PREP_DISPATCH_NO_TAG, |
| PREP_DISPATCH_NO_BUDGET, |
| }; |
| |
| static enum prep_dispatch blk_mq_prep_dispatch_rq(struct request *rq, |
| bool need_budget) |
| { |
| struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
| int budget_token = -1; |
| |
| if (need_budget) { |
| budget_token = blk_mq_get_dispatch_budget(rq->q); |
| if (budget_token < 0) { |
| blk_mq_put_driver_tag(rq); |
| return PREP_DISPATCH_NO_BUDGET; |
| } |
| blk_mq_set_rq_budget_token(rq, budget_token); |
| } |
| |
| 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)) { |
| /* |
| * All budgets not got from this function will be put |
| * together during handling partial dispatch |
| */ |
| if (need_budget) |
| blk_mq_put_dispatch_budget(rq->q, budget_token); |
| return PREP_DISPATCH_NO_TAG; |
| } |
| } |
| |
| return PREP_DISPATCH_OK; |
| } |
| |
| /* release all allocated budgets before calling to blk_mq_dispatch_rq_list */ |
| static void blk_mq_release_budgets(struct request_queue *q, |
| struct list_head *list) |
| { |
| struct request *rq; |
| |
| list_for_each_entry(rq, list, queuelist) { |
| int budget_token = blk_mq_get_rq_budget_token(rq); |
| |
| if (budget_token >= 0) |
| blk_mq_put_dispatch_budget(q, budget_token); |
| } |
| } |
| |
| /* |
| * blk_mq_commit_rqs will notify driver using bd->last that there is no |
| * more requests. (See comment in struct blk_mq_ops for commit_rqs for |
| * details) |
| * Attention, we should explicitly call this in unusual cases: |
| * 1) did not queue everything initially scheduled to queue |
| * 2) the last attempt to queue a request failed |
| */ |
| static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int queued, |
| bool from_schedule) |
| { |
| if (hctx->queue->mq_ops->commit_rqs && queued) { |
| trace_block_unplug(hctx->queue, queued, !from_schedule); |
| hctx->queue->mq_ops->commit_rqs(hctx); |
| } |
| } |
| |
| /* |
| * Returns true if we did some work AND can potentially do more. |
| */ |
| bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list, |
| unsigned int nr_budgets) |
| { |
| enum prep_dispatch prep; |
| struct request_queue *q = hctx->queue; |
| struct request *rq; |
| int queued; |
| blk_status_t ret = BLK_STS_OK; |
| bool needs_resource = false; |
| |
| if (list_empty(list)) |
| return false; |
| |
| /* |
| * Now process all the entries, sending them to the driver. |
| */ |
| queued = 0; |
| do { |
| struct blk_mq_queue_data bd; |
| |
| rq = list_first_entry(list, struct request, queuelist); |
| |
| WARN_ON_ONCE(hctx != rq->mq_hctx); |
| prep = blk_mq_prep_dispatch_rq(rq, !nr_budgets); |
| if (prep != PREP_DISPATCH_OK) |
| break; |
| |
| list_del_init(&rq->queuelist); |
| |
| bd.rq = rq; |
| bd.last = list_empty(list); |
| |
| /* |
| * once the request is queued to lld, no need to cover the |
| * budget any more |
| */ |
| if (nr_budgets) |
| nr_budgets--; |
| ret = q->mq_ops->queue_rq(hctx, &bd); |
| switch (ret) { |
| case BLK_STS_OK: |
| queued++; |
| break; |
| case BLK_STS_RESOURCE: |
| needs_resource = true; |
| fallthrough; |
| case BLK_STS_DEV_RESOURCE: |
| blk_mq_handle_dev_resource(rq, list); |
| goto out; |
| default: |
| blk_mq_end_request(rq, ret); |
| } |
| } while (!list_empty(list)); |
| out: |
| /* 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) || ret != BLK_STS_OK) |
| blk_mq_commit_rqs(hctx, queued, false); |
| |
| /* |
| * 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; |
| /* For non-shared tags, the RESTART check will suffice */ |
| bool no_tag = prep == PREP_DISPATCH_NO_TAG && |
| ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) || |
| blk_mq_is_shared_tags(hctx->flags)); |
| |
| if (nr_budgets) |
| blk_mq_release_budgets(q, list); |
| |
| spin_lock(&hctx->lock); |
| list_splice_tail_init(list, &hctx->dispatch); |
| spin_unlock(&hctx->lock); |
| |
| /* |
| * Order adding requests to hctx->dispatch and checking |
| * SCHED_RESTART flag. The pair of this smp_mb() is the one |
| * in blk_mq_sched_restart(). Avoid restart code path to |
| * miss the new added requests to hctx->dispatch, meantime |
| * SCHED_RESTART is observed here. |
| */ |
| smp_mb(); |
| |
| /* |
| * 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. We'll do |
| * similar if we couldn't get budget or couldn't lock a zone |
| * and SCHED_RESTART is set. |
| */ |
| needs_restart = blk_mq_sched_needs_restart(hctx); |
| if (prep == PREP_DISPATCH_NO_BUDGET) |
| needs_resource = true; |
| if (!needs_restart || |
| (no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) |
| blk_mq_run_hw_queue(hctx, true); |
| else if (needs_resource) |
| blk_mq_delay_run_hw_queue(hctx, BLK_MQ_RESOURCE_DELAY); |
| |
| blk_mq_update_dispatch_busy(hctx, true); |
| return false; |
| } |
| |
| blk_mq_update_dispatch_busy(hctx, false); |
| return true; |
| } |
| |
| 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; |
| } |
| |
| /* |
| * ->next_cpu is always calculated from hctx->cpumask, so simply use |
| * it for speeding up the check |
| */ |
| static bool blk_mq_hctx_empty_cpumask(struct blk_mq_hw_ctx *hctx) |
| { |
| return hctx->next_cpu >= nr_cpu_ids; |
| } |
| |
| /* |
| * 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; |
| |
| /* Switch to unbound if no allowable CPUs in this hctx */ |
| if (hctx->queue->nr_hw_queues == 1 || blk_mq_hctx_empty_cpumask(hctx)) |
| 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 a hardware queue asynchronously. |
| * @hctx: Pointer to the hardware queue to run. |
| * @msecs: Milliseconds 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) |
| { |
| if (unlikely(blk_mq_hctx_stopped(hctx))) |
| return; |
| kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, |
| msecs_to_jiffies(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) |
| { |
| bool need_run; |
| |
| /* |
| * We can't run the queue inline with interrupts disabled. |
| */ |
| WARN_ON_ONCE(!async && in_interrupt()); |
| |
| might_sleep_if(!async && hctx->flags & BLK_MQ_F_BLOCKING); |
| |
| /* |
| * 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. |
| */ |
| __blk_mq_run_dispatch_ops(hctx->queue, false, |
| need_run = !blk_queue_quiesced(hctx->queue) && |
| blk_mq_hctx_has_pending(hctx)); |
| |
| if (!need_run) |
| return; |
| |
| if (async || !cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) { |
| blk_mq_delay_run_hw_queue(hctx, 0); |
| return; |
| } |
| |
| blk_mq_run_dispatch_ops(hctx->queue, |
| blk_mq_sched_dispatch_requests(hctx)); |
| } |
| EXPORT_SYMBOL(blk_mq_run_hw_queue); |
| |
| /* |
| * Return prefered queue to dispatch from (if any) for non-mq aware IO |
| * scheduler. |
| */ |
| static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q) |
| { |
| struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); |
| /* |
| * If the IO scheduler does not respect hardware queues when |
| * dispatching, we just don't bother with multiple HW queues and |
| * dispatch from hctx for the current CPU since running multiple queues |
| * just causes lock contention inside the scheduler and pointless cache |
| * bouncing. |
| */ |
| struct blk_mq_hw_ctx *hctx = ctx->hctxs[HCTX_TYPE_DEFAULT]; |
| |
| if (!blk_mq_hctx_stopped(hctx)) |
| return hctx; |
| return NULL; |
| } |
| |
| /** |
| * blk_mq_run_hw_queues - 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, *sq_hctx; |
| unsigned long i; |
| |
| sq_hctx = NULL; |
| if (blk_queue_sq_sched(q)) |
| sq_hctx = blk_mq_get_sq_hctx(q); |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (blk_mq_hctx_stopped(hctx)) |
| continue; |
| /* |
| * Dispatch from this hctx either if there's no hctx preferred |
| * by IO scheduler or if it has requests that bypass the |
| * scheduler. |
| */ |
| if (!sq_hctx || sq_hctx == hctx || |
| !list_empty_careful(&hctx->dispatch)) |
| blk_mq_run_hw_queue(hctx, async); |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_run_hw_queues); |
| |
| /** |
| * blk_mq_delay_run_hw_queues - Run all hardware queues asynchronously. |
| * @q: Pointer to the request queue to run. |
| * @msecs: Milliseconds of delay to wait before running the queues. |
| */ |
| void blk_mq_delay_run_hw_queues(struct request_queue *q, unsigned long msecs) |
| { |
| struct blk_mq_hw_ctx *hctx, *sq_hctx; |
| unsigned long i; |
| |
| sq_hctx = NULL; |
| if (blk_queue_sq_sched(q)) |
| sq_hctx = blk_mq_get_sq_hctx(q); |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (blk_mq_hctx_stopped(hctx)) |
| continue; |
| /* |
| * If there is already a run_work pending, leave the |
| * pending delay untouched. Otherwise, a hctx can stall |
| * if another hctx is re-delaying the other's work |
| * before the work executes. |
| */ |
| if (delayed_work_pending(&hctx->run_work)) |
| continue; |
| /* |
| * Dispatch from this hctx either if there's no hctx preferred |
| * by IO scheduler or if it has requests that bypass the |
| * scheduler. |
| */ |
| if (!sq_hctx || sq_hctx == hctx || |
| !list_empty_careful(&hctx->dispatch)) |
| blk_mq_delay_run_hw_queue(hctx, msecs); |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_delay_run_hw_queues); |
| |
| /* |
| * 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; |
| unsigned long 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, hctx->flags & BLK_MQ_F_BLOCKING); |
| } |
| EXPORT_SYMBOL(blk_mq_start_hw_queue); |
| |
| void blk_mq_start_hw_queues(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned long 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; |
| unsigned long i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| blk_mq_start_stopped_hw_queue(hctx, async || |
| (hctx->flags & BLK_MQ_F_BLOCKING)); |
| } |
| 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 = |
| container_of(work, struct blk_mq_hw_ctx, run_work.work); |
| |
| blk_mq_run_dispatch_ops(hctx->queue, |
| blk_mq_sched_dispatch_requests(hctx)); |
| } |
| |
| /** |
| * blk_mq_request_bypass_insert - Insert a request at dispatch list. |
| * @rq: Pointer to request to be inserted. |
| * @flags: BLK_MQ_INSERT_* |
| * |
| * Should only be used carefully, when the caller knows we want to |
| * bypass a potential IO scheduler on the target device. |
| */ |
| static void blk_mq_request_bypass_insert(struct request *rq, blk_insert_t flags) |
| { |
| struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
| |
| spin_lock(&hctx->lock); |
| if (flags & BLK_MQ_INSERT_AT_HEAD) |
| list_add(&rq->queuelist, &hctx->dispatch); |
| else |
| list_add_tail(&rq->queuelist, &hctx->dispatch); |
| spin_unlock(&hctx->lock); |
| } |
| |
| static void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, |
| struct blk_mq_ctx *ctx, struct list_head *list, |
| bool run_queue_async) |
| { |
| struct request *rq; |
| enum hctx_type type = hctx->type; |
| |
| /* |
| * Try to issue requests directly if the hw queue isn't busy to save an |
| * extra enqueue & dequeue to the sw queue. |
| */ |
| if (!hctx->dispatch_busy && !run_queue_async) { |
| blk_mq_run_dispatch_ops(hctx->queue, |
| blk_mq_try_issue_list_directly(hctx, list)); |
| if (list_empty(list)) |
| goto out; |
| } |
| |
| /* |
| * 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(rq); |
| if (rq->cmd_flags & REQ_NOWAIT) |
| run_queue_async = true; |
| } |
| |
| spin_lock(&ctx->lock); |
| list_splice_tail_init(list, &ctx->rq_lists[type]); |
| blk_mq_hctx_mark_pending(hctx, ctx); |
| spin_unlock(&ctx->lock); |
| out: |
| blk_mq_run_hw_queue(hctx, run_queue_async); |
| } |
| |
| static void blk_mq_insert_request(struct request *rq, blk_insert_t flags) |
| { |
| struct request_queue *q = rq->q; |
| struct blk_mq_ctx *ctx = rq->mq_ctx; |
| struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
| |
| if (blk_rq_is_passthrough(rq)) { |
| /* |
| * Passthrough request have to be added to hctx->dispatch |
| * directly. The device may be in a situation where it can't |
| * handle FS request, and always returns BLK_STS_RESOURCE for |
| * them, which gets them added to hctx->dispatch. |
| * |
| * If a passthrough request is required to unblock the queues, |
| * and it is added to the scheduler queue, there is no chance to |
| * dispatch it given we prioritize requests in hctx->dispatch. |
| */ |
| blk_mq_request_bypass_insert(rq, flags); |
| } else if (req_op(rq) == REQ_OP_FLUSH) { |
| /* |
| * Firstly normal IO request is inserted to scheduler queue or |
| * sw queue, meantime we add flush request to dispatch queue( |
| * hctx->dispatch) directly and there is at most one in-flight |
| * flush request for each hw queue, so it doesn't matter to add |
| * flush request to tail or front of the dispatch queue. |
| * |
| * Secondly in case of NCQ, flush request belongs to non-NCQ |
| * command, and queueing it will fail when there is any |
| * in-flight normal IO request(NCQ command). When adding flush |
| * rq to the front of hctx->dispatch, it is easier to introduce |
| * extra time to flush rq's latency because of S_SCHED_RESTART |
| * compared with adding to the tail of dispatch queue, then |
| * chance of flush merge is increased, and less flush requests |
| * will be issued to controller. It is observed that ~10% time |
| * is saved in blktests block/004 on disk attached to AHCI/NCQ |
| * drive when adding flush rq to the front of hctx->dispatch. |
| * |
| * Simply queue flush rq to the front of hctx->dispatch so that |
| * intensive flush workloads can benefit in case of NCQ HW. |
| */ |
| blk_mq_request_bypass_insert(rq, BLK_MQ_INSERT_AT_HEAD); |
| } else if (q->elevator) { |
| LIST_HEAD(list); |
| |
| WARN_ON_ONCE(rq->tag != BLK_MQ_NO_TAG); |
| |
| list_add(&rq->queuelist, &list); |
| q->elevator->type->ops.insert_requests(hctx, &list, flags); |
| } else { |
| trace_block_rq_insert(rq); |
| |
| spin_lock(&ctx->lock); |
| if (flags & BLK_MQ_INSERT_AT_HEAD) |
| list_add(&rq->queuelist, &ctx->rq_lists[hctx->type]); |
| else |
| list_add_tail(&rq->queuelist, |
| &ctx->rq_lists[hctx->type]); |
| blk_mq_hctx_mark_pending(hctx, ctx); |
| spin_unlock(&ctx->lock); |
| } |
| } |
| |
| static void blk_mq_bio_to_request(struct request *rq, struct bio *bio, |
| unsigned int nr_segs) |
| { |
| int err; |
| |
| 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); |
| |
| /* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */ |
| err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO); |
| WARN_ON_ONCE(err); |
| |
| blk_account_io_start(rq); |
| } |
| |
| static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, bool last) |
| { |
| struct request_queue *q = rq->q; |
| struct blk_mq_queue_data bd = { |
| .rq = rq, |
| .last = last, |
| }; |
| blk_status_t ret; |
| |
| /* |
| * 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); |
| 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); |
| break; |
| } |
| |
| return ret; |
| } |
| |
| static bool blk_mq_get_budget_and_tag(struct request *rq) |
| { |
| int budget_token; |
| |
| budget_token = blk_mq_get_dispatch_budget(rq->q); |
| if (budget_token < 0) |
| return false; |
| blk_mq_set_rq_budget_token(rq, budget_token); |
| if (!blk_mq_get_driver_tag(rq)) { |
| blk_mq_put_dispatch_budget(rq->q, budget_token); |
| return false; |
| } |
| return true; |
| } |
| |
| /** |
| * 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. |
| * |
| * 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_status_t ret; |
| |
| if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { |
| blk_mq_insert_request(rq, 0); |
| return; |
| } |
| |
| if ((rq->rq_flags & RQF_USE_SCHED) || !blk_mq_get_budget_and_tag(rq)) { |
| blk_mq_insert_request(rq, 0); |
| blk_mq_run_hw_queue(hctx, rq->cmd_flags & REQ_NOWAIT); |
| return; |
| } |
| |
| ret = __blk_mq_issue_directly(hctx, rq, true); |
| switch (ret) { |
| case BLK_STS_OK: |
| break; |
| case BLK_STS_RESOURCE: |
| case BLK_STS_DEV_RESOURCE: |
| blk_mq_request_bypass_insert(rq, 0); |
| blk_mq_run_hw_queue(hctx, false); |
| break; |
| default: |
| blk_mq_end_request(rq, ret); |
| break; |
| } |
| } |
| |
| static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) |
| { |
| struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
| |
| if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(rq->q)) { |
| blk_mq_insert_request(rq, 0); |
| return BLK_STS_OK; |
| } |
| |
| if (!blk_mq_get_budget_and_tag(rq)) |
| return BLK_STS_RESOURCE; |
| return __blk_mq_issue_directly(hctx, rq, last); |
| } |
| |
| static void blk_mq_plug_issue_direct(struct blk_plug *plug) |
| { |
| struct blk_mq_hw_ctx *hctx = NULL; |
| struct request *rq; |
| int queued = 0; |
| blk_status_t ret = BLK_STS_OK; |
| |
| while ((rq = rq_list_pop(&plug->mq_list))) { |
| bool last = rq_list_empty(plug->mq_list); |
| |
| if (hctx != rq->mq_hctx) { |
| if (hctx) { |
| blk_mq_commit_rqs(hctx, queued, false); |
| queued = 0; |
| } |
| hctx = rq->mq_hctx; |
| } |
| |
| ret = blk_mq_request_issue_directly(rq, last); |
| switch (ret) { |
| case BLK_STS_OK: |
| queued++; |
| break; |
| case BLK_STS_RESOURCE: |
| case BLK_STS_DEV_RESOURCE: |
| blk_mq_request_bypass_insert(rq, 0); |
| blk_mq_run_hw_queue(hctx, false); |
| goto out; |
| default: |
| blk_mq_end_request(rq, ret); |
| break; |
| } |
| } |
| |
| out: |
| if (ret != BLK_STS_OK) |
| blk_mq_commit_rqs(hctx, queued, false); |
| } |
| |
| static void __blk_mq_flush_plug_list(struct request_queue *q, |
| struct blk_plug *plug) |
| { |
| if (blk_queue_quiesced(q)) |
| return; |
| q->mq_ops->queue_rqs(&plug->mq_list); |
| } |
| |
| static void blk_mq_dispatch_plug_list(struct blk_plug *plug, bool from_sched) |
| { |
| struct blk_mq_hw_ctx *this_hctx = NULL; |
| struct blk_mq_ctx *this_ctx = NULL; |
| struct request *requeue_list = NULL; |
| struct request **requeue_lastp = &requeue_list; |
| unsigned int depth = 0; |
| bool is_passthrough = false; |
| LIST_HEAD(list); |
| |
| do { |
| struct request *rq = rq_list_pop(&plug->mq_list); |
| |
| if (!this_hctx) { |
| this_hctx = rq->mq_hctx; |
| this_ctx = rq->mq_ctx; |
| is_passthrough = blk_rq_is_passthrough(rq); |
| } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx || |
| is_passthrough != blk_rq_is_passthrough(rq)) { |
| rq_list_add_tail(&requeue_lastp, rq); |
| continue; |
| } |
| list_add(&rq->queuelist, &list); |
| depth++; |
| } while (!rq_list_empty(plug->mq_list)); |
| |
| plug->mq_list = requeue_list; |
| trace_block_unplug(this_hctx->queue, depth, !from_sched); |
| |
| percpu_ref_get(&this_hctx->queue->q_usage_counter); |
| /* passthrough requests should never be issued to the I/O scheduler */ |
| if (is_passthrough) { |
| spin_lock(&this_hctx->lock); |
| list_splice_tail_init(&list, &this_hctx->dispatch); |
| spin_unlock(&this_hctx->lock); |
| blk_mq_run_hw_queue(this_hctx, from_sched); |
| } else if (this_hctx->queue->elevator) { |
| this_hctx->queue->elevator->type->ops.insert_requests(this_hctx, |
| &list, 0); |
| blk_mq_run_hw_queue(this_hctx, from_sched); |
| } else { |
| blk_mq_insert_requests(this_hctx, this_ctx, &list, from_sched); |
| } |
| percpu_ref_put(&this_hctx->queue->q_usage_counter); |
| } |
| |
| void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
| { |
| struct request *rq; |
| |
| /* |
| * We may have been called recursively midway through handling |
| * plug->mq_list via a schedule() in the driver's queue_rq() callback. |
| * To avoid mq_list changing under our feet, clear rq_count early and |
| * bail out specifically if rq_count is 0 rather than checking |
| * whether the mq_list is empty. |
| */ |
| if (plug->rq_count == 0) |
| return; |
| plug->rq_count = 0; |
| |
| if (!plug->multiple_queues && !plug->has_elevator && !from_schedule) { |
| struct request_queue *q; |
| |
| rq = rq_list_peek(&plug->mq_list); |
| q = rq->q; |
| |
| /* |
| * Peek first request and see if we have a ->queue_rqs() hook. |
| * If we do, we can dispatch the whole plug list in one go. We |
| * already know at this point that all requests belong to the |
| * same queue, caller must ensure that's the case. |
| */ |
| if (q->mq_ops->queue_rqs) { |
| blk_mq_run_dispatch_ops(q, |
| __blk_mq_flush_plug_list(q, plug)); |
| if (rq_list_empty(plug->mq_list)) |
| return; |
| } |
| |
| blk_mq_run_dispatch_ops(q, |
| blk_mq_plug_issue_direct(plug)); |
| if (rq_list_empty(plug->mq_list)) |
| return; |
| } |
| |
| do { |
| blk_mq_dispatch_plug_list(plug, from_schedule); |
| } while (!rq_list_empty(plug->mq_list)); |
| } |
| |
| static void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, |
| struct list_head *list) |
| { |
| int queued = 0; |
| blk_status_t ret = BLK_STS_OK; |
| |
| while (!list_empty(list)) { |
| 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)); |
| switch (ret) { |
| case BLK_STS_OK: |
| queued++; |
| break; |
| case BLK_STS_RESOURCE: |
| case BLK_STS_DEV_RESOURCE: |
| blk_mq_request_bypass_insert(rq, 0); |
| if (list_empty(list)) |
| blk_mq_run_hw_queue(hctx, false); |
| goto out; |
| default: |
| blk_mq_end_request(rq, ret); |
| break; |
| } |
| } |
| |
| out: |
| if (ret != BLK_STS_OK) |
| blk_mq_commit_rqs(hctx, queued, false); |
| } |
| |
| static bool blk_mq_attempt_bio_merge(struct request_queue *q, |
| struct bio *bio, unsigned int nr_segs) |
| { |
| if (!blk_queue_nomerges(q) && bio_mergeable(bio)) { |
| if (blk_attempt_plug_merge(q, bio, nr_segs)) |
| return true; |
| if (blk_mq_sched_bio_merge(q, bio, nr_segs)) |
| return true; |
| } |
| return false; |
| } |
| |
| static struct request *blk_mq_get_new_requests(struct request_queue *q, |
| struct blk_plug *plug, |
| struct bio *bio, |
| unsigned int nsegs) |
| { |
| struct blk_mq_alloc_data data = { |
| .q = q, |
| .nr_tags = 1, |
| .cmd_flags = bio->bi_opf, |
| }; |
| struct request *rq; |
| |
| rq_qos_throttle(q, bio); |
| |
| if (plug) { |
| data.nr_tags = plug->nr_ios; |
| plug->nr_ios = 1; |
| data.cached_rq = &plug->cached_rq; |
| } |
| |
| rq = __blk_mq_alloc_requests(&data); |
| if (rq) |
| return rq; |
| rq_qos_cleanup(q, bio); |
| if (bio->bi_opf & REQ_NOWAIT) |
| bio_wouldblock_error(bio); |
| return NULL; |
| } |
| |
| /* |
| * Check if there is a suitable cached request and return it. |
| */ |
| static struct request *blk_mq_peek_cached_request(struct blk_plug *plug, |
| struct request_queue *q, blk_opf_t opf) |
| { |
| enum hctx_type type = blk_mq_get_hctx_type(opf); |
| struct request *rq; |
| |
| if (!plug) |
| return NULL; |
| rq = rq_list_peek(&plug->cached_rq); |
| if (!rq || rq->q != q) |
| return NULL; |
| if (type != rq->mq_hctx->type && |
| (type != HCTX_TYPE_READ || rq->mq_hctx->type != HCTX_TYPE_DEFAULT)) |
| return NULL; |
| if (op_is_flush(rq->cmd_flags) != op_is_flush(opf)) |
| return NULL; |
| return rq; |
| } |
| |
| static void blk_mq_use_cached_rq(struct request *rq, struct blk_plug *plug, |
| struct bio *bio) |
| { |
| WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq); |
| |
| /* |
| * If any qos ->throttle() end up blocking, we will have flushed the |
| * plug and hence killed the cached_rq list as well. Pop this entry |
| * before we throttle. |
| */ |
| plug->cached_rq = rq_list_next(rq); |
| rq_qos_throttle(rq->q, bio); |
| |
| blk_mq_rq_time_init(rq, 0); |
| rq->cmd_flags = bio->bi_opf; |
| INIT_LIST_HEAD(&rq->queuelist); |
| } |
| |
| static bool bio_unaligned(const struct bio *bio, struct request_queue *q) |
| { |
| unsigned int bs_mask = queue_logical_block_size(q) - 1; |
| |
| /* .bi_sector of any zero sized bio need to be initialized */ |
| if ((bio->bi_iter.bi_size & bs_mask) || |
| ((bio->bi_iter.bi_sector << SECTOR_SHIFT) & bs_mask)) |
| return true; |
| return false; |
| } |
| |
| /** |
| * blk_mq_submit_bio - Create and send a request to block device. |
| * @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. |
| */ |
| void blk_mq_submit_bio(struct bio *bio) |
| { |
| struct request_queue *q = bdev_get_queue(bio->bi_bdev); |
| struct blk_plug *plug = current->plug; |
| const int is_sync = op_is_sync(bio->bi_opf); |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int nr_segs = 1; |
| struct request *rq; |
| blk_status_t ret; |
| |
| /* |
| * If the plug has a cached request for this queue, try to use it. |
| */ |
| rq = blk_mq_peek_cached_request(plug, q, bio->bi_opf); |
| |
| /* |
| * A BIO that was released from a zone write plug has already been |
| * through the preparation in this function, already holds a reference |
| * on the queue usage counter, and is the only write BIO in-flight for |
| * the target zone. Go straight to preparing a request for it. |
| */ |
| if (bio_zone_write_plugging(bio)) { |
| nr_segs = bio->__bi_nr_segments; |
| if (rq) |
| blk_queue_exit(q); |
| goto new_request; |
| } |
| |
| bio = blk_queue_bounce(bio, q); |
| |
| /* |
| * The cached request already holds a q_usage_counter reference and we |
| * don't have to acquire a new one if we use it. |
| */ |
| if (!rq) { |
| if (unlikely(bio_queue_enter(bio))) |
| return; |
| } |
| |
| /* |
| * Device reconfiguration may change logical block size, so alignment |
| * check has to be done with queue usage counter held |
| */ |
| if (unlikely(bio_unaligned(bio, q))) { |
| bio_io_error(bio); |
| goto queue_exit; |
| } |
| |
| if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { |
| bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); |
| if (!bio) |
| goto queue_exit; |
| } |
| if (!bio_integrity_prep(bio)) |
| goto queue_exit; |
| |
| if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) |
| goto queue_exit; |
| |
| if (blk_queue_is_zoned(q) && blk_zone_plug_bio(bio, nr_segs)) |
| goto queue_exit; |
| |
| new_request: |
| if (!rq) { |
| rq = blk_mq_get_new_requests(q, plug, bio, nr_segs); |
| if (unlikely(!rq)) |
| goto queue_exit; |
| } else { |
| blk_mq_use_cached_rq(rq, plug, bio); |
| } |
| |
| trace_block_getrq(bio); |
| |
| rq_qos_track(q, rq, bio); |
| |
| blk_mq_bio_to_request(rq, bio, nr_segs); |
| |
| ret = blk_crypto_rq_get_keyslot(rq); |
| if (ret != BLK_STS_OK) { |
| bio->bi_status = ret; |
| bio_endio(bio); |
| blk_mq_free_request(rq); |
| return; |
| } |
| |
| if (bio_zone_write_plugging(bio)) |
| blk_zone_write_plug_init_request(rq); |
| |
| if (op_is_flush(bio->bi_opf) && blk_insert_flush(rq)) |
| return; |
| |
| if (plug) { |
| blk_add_rq_to_plug(plug, rq); |
| return; |
| } |
| |
| hctx = rq->mq_hctx; |
| if ((rq->rq_flags & RQF_USE_SCHED) || |
| (hctx->dispatch_busy && (q->nr_hw_queues == 1 || !is_sync))) { |
| blk_mq_insert_request(rq, 0); |
| blk_mq_run_hw_queue(hctx, true); |
| } else { |
| blk_mq_run_dispatch_ops(q, blk_mq_try_issue_directly(hctx, rq)); |
| } |
| return; |
| |
| queue_exit: |
| /* |
| * Don't drop the queue reference if we were trying to use a cached |
| * request and thus didn't acquire one. |
| */ |
| if (!rq) |
| blk_queue_exit(q); |
| } |
| |
| #ifdef CONFIG_BLK_MQ_STACKING |
| /** |
| * blk_insert_cloned_request - Helper for stacking drivers to submit a request |
| * @rq: the request being queued |
| */ |
| blk_status_t blk_insert_cloned_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| unsigned int max_sectors = blk_queue_get_max_sectors(rq); |
| unsigned int max_segments = blk_rq_get_max_segments(rq); |
| blk_status_t ret; |
| |
| if (blk_rq_sectors(rq) > max_sectors) { |
| /* |
| * SCSI device does not have a good way to return if |
| * Write Same/Zero is actually supported. If a device rejects |
| * a non-read/write command (discard, write same,etc.) the |
| * low-level device driver will set the relevant queue limit to |
| * 0 to prevent blk-lib from issuing more of the offending |
| * operations. Commands queued prior to the queue limit being |
| * reset need to be completed with BLK_STS_NOTSUPP to avoid I/O |
| * errors being propagated to upper layers. |
| */ |
| if (max_sectors == 0) |
| return BLK_STS_NOTSUPP; |
| |
| printk(KERN_ERR "%s: over max size limit. (%u > %u)\n", |
| __func__, blk_rq_sectors(rq), max_sectors); |
| return BLK_STS_IOERR; |
| } |
| |
| /* |
| * The queue settings related to segment counting may differ from the |
| * original queue. |
| */ |
| rq->nr_phys_segments = blk_recalc_rq_segments(rq); |
| if (rq->nr_phys_segments > max_segments) { |
| printk(KERN_ERR "%s: over max segments limit. (%u > %u)\n", |
| __func__, rq->nr_phys_segments, max_segments); |
| return BLK_STS_IOERR; |
| } |
| |
| if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq))) |
| return BLK_STS_IOERR; |
| |
| ret = blk_crypto_rq_get_keyslot(rq); |
| if (ret != BLK_STS_OK) |
| return ret; |
| |
| blk_account_io_start(rq); |
| |
| /* |
| * Since we have a scheduler attached on the top device, |
| * bypass a potential scheduler on the bottom device for |
| * insert. |
| */ |
| blk_mq_run_dispatch_ops(q, |
| ret = blk_mq_request_issue_directly(rq, true)); |
| if (ret) |
| blk_account_io_done(rq, blk_time_get_ns()); |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(blk_insert_cloned_request); |
| |
| /** |
| * blk_rq_unprep_clone - Helper function to free all bios in a cloned request |
| * @rq: the clone request to be cleaned up |
| * |
| * Description: |
| * Free all bios in @rq for a cloned request. |
| */ |
| void blk_rq_unprep_clone(struct request *rq) |
| { |
| struct bio *bio; |
| |
| while ((bio = rq->bio) != NULL) { |
| rq->bio = bio->bi_next; |
| |
| bio_put(bio); |
| } |
| } |
| EXPORT_SYMBOL_GPL(blk_rq_unprep_clone); |
| |
| /** |
| * blk_rq_prep_clone - Helper function to setup clone request |
| * @rq: the request to be setup |
| * @rq_src: original request to be cloned |
| * @bs: bio_set that bios for clone are allocated from |
| * @gfp_mask: memory allocation mask for bio |
| * @bio_ctr: setup function to be called for each clone bio. |
| * Returns %0 for success, non %0 for failure. |
| * @data: private data to be passed to @bio_ctr |
| * |
| * Description: |
| * Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq. |
| * Also, pages which the original bios are pointing to are not copied |
| * and the cloned bios just point same pages. |
| * So cloned bios must be completed before original bios, which means |
| * the caller must complete @rq before @rq_src. |
| */ |
| int blk_rq_prep_clone(struct request *rq, struct request *rq_src, |
| struct bio_set *bs, gfp_t gfp_mask, |
| int (*bio_ctr)(struct bio *, struct bio *, void *), |
| void *data) |
| { |
| struct bio *bio, *bio_src; |
| |
| if (!bs) |
| bs = &fs_bio_set; |
| |
| __rq_for_each_bio(bio_src, rq_src) { |
| bio = bio_alloc_clone(rq->q->disk->part0, bio_src, gfp_mask, |
| bs); |
| if (!bio) |
| goto free_and_out; |
| |
| if (bio_ctr && bio_ctr(bio, bio_src, data)) |
| goto free_and_out; |
| |
| if (rq->bio) { |
| rq->biotail->bi_next = bio; |
| rq->biotail = bio; |
| } else { |
| rq->bio = rq->biotail = bio; |
| } |
| bio = NULL; |
| } |
| |
| /* Copy attributes of the original request to the clone request. */ |
| rq->__sector = blk_rq_pos(rq_src); |
| rq->__data_len = blk_rq_bytes(rq_src); |
| if (rq_src->rq_flags & RQF_SPECIAL_PAYLOAD) { |
| rq->rq_flags |= RQF_SPECIAL_PAYLOAD; |
| rq->special_vec = rq_src->special_vec; |
| } |
| rq->nr_phys_segments = rq_src->nr_phys_segments; |
| rq->ioprio = rq_src->ioprio; |
| rq->write_hint = rq_src->write_hint; |
| |
| if (rq->bio && blk_crypto_rq_bio_prep(rq, rq->bio, gfp_mask) < 0) |
| goto free_and_out; |
| |
| return 0; |
| |
| free_and_out: |
| if (bio) |
| bio_put(bio); |
| blk_rq_unprep_clone(rq); |
| |
| return -ENOMEM; |
| } |
| EXPORT_SYMBOL_GPL(blk_rq_prep_clone); |
| #endif /* CONFIG_BLK_MQ_STACKING */ |
| |
| /* |
| * 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; |
| |
| |