diff options
Diffstat (limited to 'block/blk-mq.c')
| -rw-r--r-- | block/blk-mq.c | 4981 |
1 files changed, 4981 insertions, 0 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c new file mode 100644 index 000000000..b3f99dda4 --- /dev/null +++ b/block/blk-mq.c @@ -0,0 +1,4981 @@ +// 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/sysctl.h> +#include <linux/sched/topology.h> +#include <linux/sched/signal.h> +#include <linux/delay.h> +#include <linux/crash_dump.h> +#include <linux/prefetch.h> +#include <linux/blk-crypto.h> +#include <linux/part_stat.h> + +#include <trace/events/block.h> + +#include <linux/blk-mq.h> +#include <linux/t10-pi.h> +#include "blk.h" +#include "blk-mq.h" +#include "blk-mq-debugfs.h" +#include "blk-mq-tag.h" +#include "blk-pm.h" +#include "blk-stat.h" +#include "blk-mq-sched.h" +#include "blk-rq-qos.h" +#include "blk-ioprio.h" + +static DEFINE_PER_CPU(struct llist_head, blk_cpu_done); + +static void blk_mq_poll_stats_start(struct request_queue *q); +static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb); + +static int blk_mq_poll_stats_bkt(const struct request *rq) +{ + int ddir, sectors, bucket; + + ddir = rq_data_dir(rq); + sectors = blk_rq_stats_sectors(rq); + + bucket = ddir + 2 * ilog2(sectors); + + if (bucket < 0) + return -1; + else if (bucket >= BLK_MQ_POLL_STATS_BKTS) + return ddir + BLK_MQ_POLL_STATS_BKTS - 2; + + return bucket; +} + +#define BLK_QC_T_SHIFT 16 +#define BLK_QC_T_INTERNAL (1U << 31) + +static inline struct blk_mq_hw_ctx *blk_qc_to_hctx(struct request_queue *q, + blk_qc_t qc) +{ + return xa_load(&q->hctx_table, + (qc & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT); +} + +static inline struct request *blk_qc_to_rq(struct blk_mq_hw_ctx *hctx, + blk_qc_t qc) +{ + unsigned int tag = qc & ((1U << BLK_QC_T_SHIFT) - 1); + + if (qc & BLK_QC_T_INTERNAL) + return blk_mq_tag_to_rq(hctx->sched_tags, tag); + return blk_mq_tag_to_rq(hctx->tags, tag); +} + +static inline blk_qc_t blk_rq_to_qc(struct request *rq) +{ + return (rq->mq_hctx->queue_num << BLK_QC_T_SHIFT) | + (rq->tag != -1 ? + rq->tag : (rq->internal_tag | BLK_QC_T_INTERNAL)); +} + +/* + * 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) && + (!mi->part->bd_partno || 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 + * @q: request queue. + * + * Note: it is driver's responsibility for making sure that quiesce has + * been started. + */ +void blk_mq_wait_quiesce_done(struct request_queue *q) +{ + if (blk_queue_has_srcu(q)) + synchronize_srcu(q->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); + blk_mq_wait_quiesce_done(q); +} +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_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 = ktime_get_ns(); + rq->part = NULL; + blk_crypto_rq_set_defaults(rq); +} +EXPORT_SYMBOL(blk_rq_init); + +static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, + struct blk_mq_tags *tags, unsigned int tag, u64 alloc_time_ns) +{ + 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_ELV)) { + rq->tag = tag; + rq->internal_tag = BLK_MQ_NO_TAG; + } else { + rq->tag = BLK_MQ_NO_TAG; + rq->internal_tag = tag; + } + rq->timeout = 0; + + if (blk_mq_need_time_stamp(rq)) + rq->start_time_ns = ktime_get_ns(); + else + rq->start_time_ns = 0; + rq->part = NULL; +#ifdef CONFIG_BLK_RQ_ALLOC_TIME + rq->alloc_time_ns = alloc_time_ns; +#endif + 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_ELV) { + struct elevator_queue *e = data->q->elevator; + + INIT_HLIST_NODE(&rq->hash); + RB_CLEAR_NODE(&rq->rb_node); + + if (!op_is_flush(data->cmd_flags) && + e->type->ops.prepare_request) { + e->type->ops.prepare_request(rq); + rq->rq_flags |= RQF_ELVPRIV; + } + } + + return rq; +} + +static inline struct request * +__blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data, + u64 alloc_time_ns) +{ + 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, alloc_time_ns); + rq_list_add(data->cached_rq, rq); + 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 = ktime_get_ns(); + + if (data->cmd_flags & REQ_NOWAIT) + data->flags |= BLK_MQ_REQ_NOWAIT; + + if (q->elevator) { + struct elevator_queue *e = q->elevator; + + data->rq_flags |= RQF_ELV; + + /* + * Flush/passthrough requests are special and go directly to the + * dispatch list. Don't include reserved tags in the + * limiting, as it isn't useful. + */ + if (!op_is_flush(data->cmd_flags) && + !blk_op_is_passthrough(data->cmd_flags) && + e->type->ops.limit_depth && + !(data->flags & BLK_MQ_REQ_RESERVED)) + e->type->ops.limit_depth(data->cmd_flags, data); + } + +retry: + data->ctx = blk_mq_get_ctx(q); + data->hctx = blk_mq_map_queue(q, data->cmd_flags, data->ctx); + if (!(data->rq_flags & RQF_ELV)) + 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, alloc_time_ns); + if (rq) + 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; + } + + return blk_mq_rq_ctx_init(data, blk_mq_tags_from_data(data), tag, + alloc_time_ns); +} + +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) + goto got_it; + return NULL; + } + 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); +got_it: + 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 = ktime_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) + blk_mq_tag_busy(data.hctx); + else + data.rq_flags |= RQF_ELV; + + 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; + rq = blk_mq_rq_ctx_init(&data, blk_mq_tags_from_data(&data), tag, + 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_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->rq_flags & RQF_MQ_INFLIGHT) + __blk_mq_dec_active_requests(hctx); + + if (rq->tag != BLK_MQ_NO_TAG) + 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; + + if ((rq->rq_flags & RQF_ELVPRIV) && + q->elevator->type->ops.finish_request) + q->elevator->type->ops.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 req_bio_endio(struct request *rq, struct bio *bio, + unsigned int nbytes, blk_status_t error) +{ + if (unlikely(error)) { + bio->bi_status = error; + } else if (req_op(rq) == REQ_OP_ZONE_APPEND) { + /* + * Partial zone append completions cannot be supported as the + * BIO fragments may end up not being written sequentially. + */ + if (bio->bi_iter.bi_size != nbytes) + bio->bi_status = BLK_STS_IOERR; + else + bio->bi_iter.bi_sector = rq->__sector; + } + + bio_advance(bio, nbytes); + + if (unlikely(rq->rq_flags & RQF_QUIET)) + bio_set_flag(bio, BIO_QUIET); + /* don't actually finish bio if it's part of flush sequence */ + if (bio->bi_iter.bi_size == 0 && !(rq->rq_flags & RQF_FLUSH_SEQ)) + bio_endio(bio); +} + +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; + +#ifdef CONFIG_BLK_DEV_INTEGRITY + if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ) + req->q->integrity.profile->complete_fn(req, total_bytes); +#endif + + /* + * 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); + + if (req_op(req) == REQ_OP_ZONE_APPEND) + bio->bi_iter.bi_sector = req->__sector; + + 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) +{ + int total_bytes; + + trace_block_rq_complete(req, error, nr_bytes); + + if (!req->bio) + return false; + +#ifdef CONFIG_BLK_DEV_INTEGRITY + if (blk_integrity_rq(req) && req_op(req) == REQ_OP_READ && + error == BLK_STS_OK) + req->q->integrity.profile->complete_fn(req, nr_bytes); +#endif + + /* + * 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) && + !(req->rq_flags & RQF_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 (bio_bytes == bio->bi_iter.bi_size) + req->bio = bio->bi_next; + + /* Completion has already been traced */ + bio_clear_flag(bio, BIO_TRACE_COMPLETION); + req_bio_endio(req, bio, bio_bytes, error); + + total_bytes += bio_bytes; + nr_bytes -= bio_bytes; + + if (!nr_bytes) + break; + } + + /* + * completely done + */ + if (!req->bio) { + /* + * Reset counters so that the request stacking driver + * can find how many bytes remain in the request + * later. + */ + req->__data_len = 0; + return false; + } + + req->__data_len -= total_bytes; + + /* update sector only for requests with clear definition of sector */ + if (!blk_rq_is_passthrough(req)) + req->__sector += total_bytes >> 9; + + /* mixed attributes always follow the first bio */ + if (req->rq_flags & RQF_MIXED_MERGE) { + req->cmd_flags &= ~REQ_FAILFAST_MASK; + req->cmd_flags |= req->bio->bi_opf & REQ_FAILFAST_MASK; + } + + if (!(req->rq_flags & RQF_SPECIAL_PAYLOAD)) { + /* + * If total number of sectors is less than the first segment + * size, something has gone terribly wrong. + */ + if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) { + blk_dump_rq_flags(req, "request botched"); + req->__data_len = blk_rq_cur_bytes(req); + } + + /* recalculate the number of segments */ + req->nr_phys_segments = blk_recalc_rq_segments(req); + } + + return true; +} +EXPORT_SYMBOL_GPL(blk_update_request); + +static void __blk_account_io_done(struct request *req, u64 now) +{ + 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_unlock(); +} + +static inline void blk_account_io_done(struct request *req, u64 now) +{ + /* + * Account IO completion. flush_rq isn't accounted as a + * normal IO on queueing nor completion. Accounting the + * containing request is enough. + */ + if (blk_do_io_stat(req) && req->part && + !(req->rq_flags & RQF_FLUSH_SEQ)) + __blk_account_io_done(req, now); +} + +static void __blk_account_io_start(struct request *rq) +{ + /* + * 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 (rq->bio) + rq->part = rq->bio->bi_bdev; + else + rq->part = rq->q->disk->part0; + + part_stat_lock(); + update_io_ticks(rq->part, jiffies, false); + part_stat_unlock(); +} + +static inline void blk_account_io_start(struct request *req) +{ + if (blk_do_io_stat(req)) + __blk_account_io_start(req); +} + +static inline void __blk_mq_end_request_acct(struct request *rq, u64 now) +{ + if (rq->rq_flags & RQF_STATS) { + blk_mq_poll_stats_start(rq->q); + 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, ktime_get_ns()); + + 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; + + /* + * All requests should have been marked as RQF_MQ_INFLIGHT, so + * update hctx->nr_active in batch + */ + if (hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) + __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 = ktime_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); + + 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? 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))) + 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) +{ + struct llist_head *list; + unsigned int cpu; + + cpu = rq->mq_ctx->cpu; + list = &per_cpu(blk_cpu_done, cpu); + if (llist_add(&rq->ipi_list, list)) { + INIT_CSD(&rq->csd, __blk_mq_complete_request_remote, rq); + smp_call_function_single_async(cpu, &rq->csd); + } +} + +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->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)) { + rq->io_start_time_ns = ktime_get_ns(); + rq->stats_sectors = blk_rq_sectors(rq); + rq->rq_flags |= RQF_STATS; + rq_qos_issue(q, rq); + } + + WARN_ON_ONCE(blk_mq_rq_state(rq) != MQ_RQ_IDLE); + + blk_add_timer(rq); + WRITE_ONCE(rq->state, MQ_RQ_IN_FLIGHT); + +#ifdef CONFIG_BLK_DEV_INTEGRITY + if (blk_integrity_rq(rq) && req_op(rq) == REQ_OP_WRITE) + q->integrity.profile->prepare_fn(rq); +#endif + if (rq->bio && rq->bio->bi_opf & REQ_POLLED) + WRITE_ONCE(rq->bio->bi_cookie, blk_rq_to_qc(rq)); +} +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; + if (!plug->has_elevator && (rq->rq_flags & RQF_ELV)) + 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) +{ + WARN_ON(irqs_disabled()); + WARN_ON(!blk_rq_is_passthrough(rq)); + + blk_account_io_start(rq); + + /* + * As plugging can be enabled for passthrough requests on a zoned + * device, directly accessing the plug instead of using blk_mq_plug() + * should not have any consequences. + */ + if (current->plug && !at_head) + blk_add_rq_to_plug(current->plug, rq); + else + blk_mq_sched_insert_request(rq, at_head, true, false); +} +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_mq_poll(rq->q, blk_rq_to_qc(rq), 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_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_sched_insert_request(rq, at_head, true, false); + + if (blk_rq_is_poll(rq)) { + blk_rq_poll_completion(rq, &wait.done); + } else { + /* + * Prevent hang_check timer from firing at us during very long + * I/O + */ + unsigned long hang_check = sysctl_hung_task_timeout_secs; + + if (hang_check) + while (!wait_for_completion_io_timeout(&wait.done, + hang_check * (HZ/2))) + ; + else + wait_for_completion_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) +{ + __blk_mq_requeue_request(rq); + + /* this request will be re-inserted to io scheduler queue */ + blk_mq_sched_requeue_request(rq); + + blk_mq_add_to_requeue_list(rq, true, kick_requeue_list); +} +EXPORT_SYMBOL(blk_mq_requeue_request); + +static void blk_mq_requeue_work(struct work_struct *work) +{ + struct request_queue *q = + container_of(work, struct request_queue, requeue_work.work); + LIST_HEAD(rq_list); + struct request *rq, *next; + + spin_lock_irq(&q->requeue_lock); + list_splice_init(&q->requeue_list, &rq_list); + spin_unlock_irq(&q->requeue_lock); + + list_for_each_entry_safe(rq, next, &rq_list, queuelist) { + if (!(rq->rq_flags & (RQF_SOFTBARRIER | RQF_DONTPREP))) + continue; + + rq->rq_flags &= ~RQF_SOFTBARRIER; + list_del_init(&rq->queuelist); + /* + * If RQF_DONTPREP, rq has contained some driver specific + * data, so insert it to hctx dispatch list to avoid any + * merge. + */ + if (rq->rq_flags & RQF_DONTPREP) + blk_mq_request_bypass_insert(rq, false, false); + else + blk_mq_sched_insert_request(rq, true, false, false); + } + + while (!list_empty(&rq_list)) { + rq = list_entry(rq_list.next, struct request, queuelist); + list_del_init(&rq->queuelist); + blk_mq_sched_insert_request(rq, false, false, false); + } + + blk_mq_run_hw_queues(q, false); +} + +void blk_mq_add_to_requeue_list(struct request *rq, bool at_head, + bool kick_requeue_list) +{ + struct request_queue *q = rq->q; + unsigned long flags; + + /* + * We abuse this flag that is otherwise used by the I/O scheduler to + * request head insertion from the workqueue. + */ + BUG_ON(rq->rq_flags & RQF_SOFTBARRIER); + + spin_lock_irqsave(&q->requeue_lock, flags); + if (at_head) { + rq->rq_flags |= RQF_SOFTBARRIER; + list_add(&rq->queuelist, &q->requeue_list); + } else { + list_add_tail(&rq->queuelist, &q->requeue_list); + } + spin_unlock_irqrestore(&q->requeue_lock, flags); + + if (kick_requeue_list) + blk_mq_kick_requeue_list(q); +} + +void blk_mq_kick_requeue_list(struct request_queue *q) +{ + kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0); +} +EXPORT_SYMBOL(blk_mq_kick_requeue_list); + +void blk_mq_delay_kick_requeue_list(struct request_queue *q, + unsigned long msecs) +{ + kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, + msecs_to_jiffies(msecs)); +} +EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list); + +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); + + 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; +} + +static 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; + return true; +} + +bool __blk_mq_get_driver_tag(struct blk_mq_hw_ctx *hctx, struct request *rq) +{ + if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_alloc_driver_tag(rq)) + return false; + + if ((hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED) && + !(rq->rq_flags & RQF_MQ_INFLIGHT)) { + rq->rq_flags |= RQF_MQ_INFLIGHT; + __blk_mq_inc_active_requests(hctx); + } + hctx->tags->rqs[rq->tag] = rq; + 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); + + /* + * 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) +{ + struct request *next = + list_first_entry_or_null(list, struct request, queuelist); + + /* + * If an I/O scheduler has been configured and we got a driver tag for + * the next request already, free it. + */ + if (next) + blk_mq_put_driver_tag(next); + + list_add(&rq->queuelist, list); + __blk_mq_requeue_request(rq); +} + +static void blk_mq_handle_zone_resource(struct request *rq, + struct list_head *zone_list) +{ + /* + * If we end up here it is because we cannot dispatch a request to a + * specific zone due to LLD level zone-write locking or other zone + * related resource not being available. In this case, set the request + * aside in zone_list for retrying it later. + */ + list_add(&rq->queuelist, zone_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); + } +} + +/* + * 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, *nxt; + int errors, queued; + blk_status_t ret = BLK_STS_OK; + LIST_HEAD(zone_list); + bool needs_resource = false; + + if (list_empty(list)) + return false; + + /* + * Now process all the entries, sending them to the driver. + */ + errors = queued = 0; + do { + struct blk_mq_queue_data bd; + + rq = list_first_entry(list, struct request, queuelist); + + 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; + + /* + * Flag last if we have no more requests, or if we have more + * but can't assign a driver tag to it. + */ + if (list_empty(list)) + bd.last = true; + else { + nxt = list_first_entry(list, struct request, queuelist); + bd.last = !blk_mq_get_driver_tag(nxt); + } + + /* + * 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; + case BLK_STS_ZONE_RESOURCE: + /* + * Move the request to zone_list and keep going through + * the dispatch list to find more requests the drive can + * accept. + */ + blk_mq_handle_zone_resource(rq, &zone_list); + needs_resource = true; + break; + default: + errors++; + blk_mq_end_request(rq, ret); + } + } while (!list_empty(list)); +out: + if (!list_empty(&zone_list)) + list_splice_tail_init(&zone_list, list); + + /* 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) || errors || needs_resource || + ret == BLK_STS_DEV_RESOURCE) && q->mq_ops->commit_rqs && queued) + q->mq_ops->commit_rqs(hctx); + /* + * 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; + } else + blk_mq_update_dispatch_busy(hctx, false); + + return (queued + errors) != 0; +} + +/** + * __blk_mq_run_hw_queue - Run a hardware queue. + * @hctx: Pointer to the hardware queue to run. + * + * Send pending requests to the hardware. + */ +static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) +{ + /* + * We can't run the queue inline with ints disabled. Ensure that + * we catch bad users of this early. + */ + WARN_ON_ONCE(in_interrupt()); + + blk_mq_run_dispatch_ops(hctx->queue, + blk_mq_sched_dispatch_requests(hctx)); +} + +static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx) +{ + int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask); + + if (cpu >= nr_cpu_ids) + cpu = cpumask_first(hctx->cpumask); + return cpu; +} + +/* + * It'd be great if the workqueue API had a way to pass + * in a mask and had some smarts for more clever placement. + * For now we just round-robin here, switching for every + * BLK_MQ_CPU_WORK_BATCH queued items. + */ +static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) +{ + bool tried = false; + int next_cpu = hctx->next_cpu; + + if (hctx->queue->nr_hw_queues == 1) + return WORK_CPU_UNBOUND; + + if (--hctx->next_cpu_batch <= 0) { +select_cpu: + next_cpu = cpumask_next_and(next_cpu, hctx->cpumask, + cpu_online_mask); + if (next_cpu >= nr_cpu_ids) + next_cpu = blk_mq_first_mapped_cpu(hctx); + hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; + } + + /* + * Do unbound schedule if we can't find a online CPU for this hctx, + * and it should only happen in the path of handling CPU DEAD. + */ + if (!cpu_online(next_cpu)) { + if (!tried) { + tried = true; + goto select_cpu; + } + + /* + * Make sure to re-select CPU next time once after CPUs + * in hctx->cpumask become online again. + */ + hctx->next_cpu = next_cpu; + hctx->next_cpu_batch = 1; + return WORK_CPU_UNBOUND; + } + + hctx->next_cpu = next_cpu; + return next_cpu; +} + +/** + * __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue. + * @hctx: Pointer to the hardware queue to run. + * @async: If we want to run the queue asynchronously. + * @msecs: Milliseconds of delay to wait before running the queue. + * + * If !@async, try to run the queue now. Else, run the queue asynchronously and + * with a delay of @msecs. + */ +static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, + unsigned long msecs) +{ + if (unlikely(blk_mq_hctx_stopped(hctx))) + return; + + if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) { + if (cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask)) { + __blk_mq_run_hw_queue(hctx); + return; + } + } + + kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, + msecs_to_jiffies(msecs)); +} + +/** + * blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously. + * @hctx: Pointer to the hardware queue to run. + * @msecs: 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) +{ + __blk_mq_delay_run_hw_queue(hctx, true, msecs); +} +EXPORT_SYMBOL(blk_mq_delay_run_hw_queue); + +/** + * blk_mq_run_hw_queue - Start to run a hardware queue. + * @hctx: Pointer to the hardware queue to run. + * @async: If we want to run the queue asynchronously. + * + * Check if the request queue is not in a quiesced state and if there are + * pending requests to be sent. If this is true, run the queue to send requests + * to hardware. + */ +void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) +{ + bool need_run; + + /* + * When queue is quiesced, we may be switching io scheduler, or + * updating nr_hw_queues, or other things, and we can't run queue + * any more, even __blk_mq_hctx_has_pending() can't be called safely. + * + * And queue will be rerun in blk_mq_unquiesce_queue() if it is + * quiesced. + */ + __blk_mq_run_dispatch_ops(hctx->queue, false, + need_run = !blk_queue_quiesced(hctx->queue) && + blk_mq_hctx_has_pending(hctx)); + + if (need_run) + __blk_mq_delay_run_hw_queue(hctx, async, 0); +} +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, false); +} +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); +} +EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); + +static void blk_mq_run_work_fn(struct work_struct *work) +{ + struct blk_mq_hw_ctx *hctx; + + hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); + + /* + * If we are stopped, don't run the queue. + */ + if (blk_mq_hctx_stopped(hctx)) + return; + + __blk_mq_run_hw_queue(hctx); +} + +static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx, + struct request *rq, + bool at_head) +{ + struct blk_mq_ctx *ctx = rq->mq_ctx; + enum hctx_type type = hctx->type; + + lockdep_assert_held(&ctx->lock); + + trace_block_rq_insert(rq); + + if (at_head) + list_add(&rq->queuelist, &ctx->rq_lists[type]); + else + list_add_tail(&rq->queuelist, &ctx->rq_lists[type]); +} + +void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, + bool at_head) +{ + struct blk_mq_ctx *ctx = rq->mq_ctx; + + lockdep_assert_held(&ctx->lock); + + __blk_mq_insert_req_list(hctx, rq, at_head); + blk_mq_hctx_mark_pending(hctx, ctx); +} + +/** + * blk_mq_request_bypass_insert - Insert a request at dispatch list. + * @rq: Pointer to request to be inserted. + * @at_head: true if the request should be inserted at the head of the list. + * @run_queue: If we should run the hardware queue after inserting the request. + * + * Should only be used carefully, when the caller knows we want to + * bypass a potential IO scheduler on the target device. + */ +void blk_mq_request_bypass_insert(struct request *rq, bool at_head, + bool run_queue) +{ + struct blk_mq_hw_ctx *hctx = rq->mq_hctx; + + spin_lock(&hctx->lock); + if (at_head) + list_add(&rq->queuelist, &hctx->dispatch); + else + list_add_tail(&rq->queuelist, &hctx->dispatch); + spin_unlock(&hctx->lock); + + if (run_queue) + blk_mq_run_hw_queue(hctx, false); +} + +void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx, + struct list_head *list) + +{ + struct request *rq; + enum hctx_type type = hctx->type; + + /* + * preemption doesn't flush plug list, so it's possible ctx->cpu is + * offline now + */ + list_for_each_entry(rq, list, queuelist) { + BUG_ON(rq->mq_ctx != ctx); + trace_block_rq_insert(rq); + } + + spin_lock(&ctx->lock); + list_splice_tail_init(list, &ctx->rq_lists[type]); + blk_mq_hctx_mark_pending(hctx, ctx); + spin_unlock(&ctx->lock); +} + +static void blk_mq_commit_rqs(struct blk_mq_hw_ctx *hctx, int *queued, + bool from_schedule) +{ + if (hctx->queue->mq_ops->commit_rqs) { + trace_block_unplug(hctx->queue, *queued, !from_schedule); + hctx->queue->mq_ops->commit_rqs(hctx); + } + *queued = 0; +} + +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; + 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 blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, + struct request *rq, + bool bypass_insert, bool last) +{ + struct request_queue *q = rq->q; + bool run_queue = true; + int budget_token; + + /* + * RCU or SRCU read lock is needed before checking quiesced flag. + * + * When queue is stopped or quiesced, ignore 'bypass_insert' from + * blk_mq_request_issue_directly(), and return BLK_STS_OK to caller, + * and avoid driver to try to dispatch again. + */ + if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { + run_queue = false; + bypass_insert = false; + goto insert; + } + + if ((rq->rq_flags & RQF_ELV) && !bypass_insert) + goto insert; + + budget_token = blk_mq_get_dispatch_budget(q); + if (budget_token < 0) + goto insert; + + blk_mq_set_rq_budget_token(rq, budget_token); + + if (!blk_mq_get_driver_tag(rq)) { + blk_mq_put_dispatch_budget(q, budget_token); + goto insert; + } + + return __blk_mq_issue_directly(hctx, rq, last); +insert: + if (bypass_insert) + return BLK_STS_RESOURCE; + + blk_mq_sched_insert_request(rq, false, run_queue, false); + + return BLK_STS_OK; +} + +/** + * blk_mq_try_issue_directly - Try to send a request directly to device driver. + * @hctx: Pointer of the associated hardware queue. + * @rq: Pointer to request to be sent. + * + * 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 = + __blk_mq_try_issue_directly(hctx, rq, false, true); + + if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) + blk_mq_request_bypass_insert(rq, false, true); + else if (ret != BLK_STS_OK) + blk_mq_end_request(rq, ret); +} + +static blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) +{ + return __blk_mq_try_issue_directly(rq->mq_hctx, rq, true, last); +} + +static void blk_mq_plug_issue_direct(struct blk_plug *plug, bool from_schedule) +{ + struct blk_mq_hw_ctx *hctx = NULL; + struct request *rq; + int queued = 0; + int errors = 0; + + while ((rq = rq_list_pop(&plug->mq_list))) { + bool last = rq_list_empty(plug->mq_list); + blk_status_t ret; + + if (hctx != rq->mq_hctx) { + if (hctx) + blk_mq_commit_rqs(hctx, &queued, from_schedule); + 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, false, true); + blk_mq_commit_rqs(hctx, &queued, from_schedule); + return; + default: + blk_mq_end_request(rq, ret); + errors++; + break; + } + } + + /* + * 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 (errors) + blk_mq_commit_rqs(hctx, &queued, from_schedule); +} + +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; + 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; + } else if (this_hctx != rq->mq_hctx || this_ctx != rq->mq_ctx) { + 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); + blk_mq_sched_insert_requests(this_hctx, this_ctx, &list, from_sched); +} + +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. + * + * Since we pass off the full list to the driver at this point, + * we do not increment the active request count for the queue. + * Bypass shared tags for now because of that. + */ + if (q->mq_ops->queue_rqs && + !(rq->mq_hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) { + 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, false)); + if (rq_list_empty(plug->mq_list)) + return; + } + + do { + blk_mq_dispatch_plug_list(plug, from_schedule); + } while (!rq_list_empty(plug->mq_list)); +} + +void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, + struct list_head *list) +{ + int queued = 0; + int errors = 0; + + while (!list_empty(list)) { + blk_status_t ret; + struct request *rq = list_first_entry(list, struct request, + queuelist); + + list_del_init(&rq->queuelist); + ret = blk_mq_request_issue_directly(rq, list_empty(list)); + if (ret != BLK_STS_OK) { + errors++; + if (ret == BLK_STS_RESOURCE || + ret == BLK_STS_DEV_RESOURCE) { + blk_mq_request_bypass_insert(rq, false, + list_empty(list)); + break; + } + blk_mq_end_request(rq, ret); + } else + queued++; + } + + /* + * If we didn't flush the entire list, we could have told + * the driver there was more coming, but that turned out to + * be a lie. + */ + if ((!list_empty(list) || errors) && + hctx->queue->mq_ops->commit_rqs && queued) + hctx->queue->mq_ops->commit_rqs(hctx); +} + +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; + + if (blk_mq_attempt_bio_merge(q, bio, nsegs)) + return NULL; + + 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; +} + +/* return true if this @rq can be used for @bio */ +static bool blk_mq_can_use_cached_rq(struct request *rq, struct blk_plug *plug, + struct bio *bio) +{ + enum hctx_type type = blk_mq_get_hctx_type(bio->bi_opf); + enum hctx_type hctx_type = rq->mq_hctx->type; + + WARN_ON_ONCE(rq_list_peek(&plug->cached_rq) != rq); + + if (type != hctx_type && + !(type == HCTX_TYPE_READ && hctx_type == HCTX_TYPE_DEFAULT)) + return false; + if (op_is_flush(rq->cmd_flags) != op_is_flush(bio->bi_opf)) + return false; + + /* + * 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); + + rq->cmd_flags = bio->bi_opf; + INIT_LIST_HEAD(&rq->queuelist); + return true; +} + +static void bio_set_ioprio(struct bio *bio) +{ + /* Nobody set ioprio so far? Initialize it based on task's nice value */ + if (IOPRIO_PRIO_CLASS(bio->bi_ioprio) == IOPRIO_CLASS_NONE) + bio->bi_ioprio = get_current_ioprio(); + blkcg_set_ioprio(bio); +} + +/** + * 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 = blk_mq_plug(bio); + const int is_sync = op_is_sync(bio->bi_opf); + struct request *rq = NULL; + unsigned int nr_segs = 1; + blk_status_t ret; + + bio = blk_queue_bounce(bio, q); + bio_set_ioprio(bio); + + if (plug) { + rq = rq_list_peek(&plug->cached_rq); + if (rq && rq->q != q) + rq = NULL; + } + if (rq) { + if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { + bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); + if (!bio) + return; + } + if (!bio_integrity_prep(bio)) + return; + if (blk_mq_attempt_bio_merge(q, bio, nr_segs)) + return; + if (blk_mq_can_use_cached_rq(rq, plug, bio)) + goto done; + percpu_ref_get(&q->q_usage_counter); + } else { + if (unlikely(bio_queue_enter(bio))) + return; + if (unlikely(bio_may_exceed_limits(bio, &q->limits))) { + bio = __bio_split_to_limits(bio, &q->limits, &nr_segs); + if (!bio) + goto fail; + } + if (!bio_integrity_prep(bio)) + goto fail; + } + + rq = blk_mq_get_new_requests(q, plug, bio, nr_segs); + if (unlikely(!rq)) { +fail: + blk_queue_exit(q); + return; + } + +done: + 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 (op_is_flush(bio->bi_opf)) { + blk_insert_flush(rq); + return; + } + + if (plug) + blk_add_rq_to_plug(plug, rq); + else if ((rq->rq_flags & RQF_ELV) || + (rq->mq_hctx->dispatch_busy && + (q->nr_hw_queues == 1 || !is_sync))) + blk_mq_sched_insert_request(rq, false, true, true); + else + blk_mq_run_dispatch_ops(rq->q, + blk_mq_try_issue_directly(rq->mq_hctx, rq)); +} + +#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(q, req_op(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 > queue_max_segments(q)) { + printk(KERN_ERR "%s: over max segments limit. (%hu > %hu)\n", + __func__, rq->nr_phys_segments, queue_max_segments(q)); + return BLK_STS_IOERR; + } + + if (q->disk && should_fail_request(q->disk->part0, blk_rq_bytes(rq))) + return BLK_STS_IOERR; + + if (blk_crypto_insert_cloned_request(rq)) + return BLK_STS_IOERR; + + 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, ktime_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; + + 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; + + rq->bio = NULL; + rq->biotail = NULL; + } + + rq->__data_len = 0; +} +EXPORT_SYMBOL_GPL(blk_steal_bios); + +static size_t order_to_size(unsigned int order) +{ + return (size_t)PAGE_SIZE << order; +} + +/* called before freeing request pool in @tags */ +static void blk_mq_clear_rq_mapping(struct blk_mq_tags *drv_tags, + struct blk_mq_tags *tags) +{ + struct page *page; + unsigned long flags; + + /* + * There is no need to clear mapping if driver tags is not initialized + * or the mapping belongs to the driver tags. + */ + if (!drv_tags || drv_tags == tags) + return; + + list_for_each_entry(page, &tags->page_list, lru) { + unsigned long start = (unsigned long)page_address(page); + unsigned long end = start + order_to_size(page->private); + int i; + + for (i = 0; i < drv_tags->nr_tags; i++) { + struct request *rq = drv_tags->rqs[i]; + unsigned long rq_addr = (unsigned long)rq; + + if (rq_addr >= start && rq_addr < end) { + WARN_ON_ONCE(req_ref_read(rq) != 0); + cmpxchg(&drv_tags->rqs[i], rq, NULL); + } + } + } + + /* + * Wait until all pending iteration is done. + * + * Request reference is cleared and it is guaranteed to be observed + * after the ->lock is released. + */ + spin_lock_irqsave(&drv_tags->lock, flags); + spin_unlock_irqrestore(&drv_tags->lock, flags); +} + +void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, + unsigned int hctx_idx) +{ + struct blk_mq_tags *drv_tags; + struct page *page; + + if (list_empty(&tags->page_list)) + return; + + if (blk_mq_is_shared_tags(set->flags)) + drv_tags = set->shared_tags; + else + drv_tags = set->tags[hctx_idx]; + + if (tags->static_rqs && set->ops->exit_request) { + int i; + + for (i = 0; i < tags->nr_tags; i++) { + struct request *rq = tags->static_rqs[i]; + + if (!rq) + continue; + set->ops->exit_request(set, rq, hctx_idx); + tags->static_rqs[i] = NULL; + } + } + + blk_mq_clear_rq_mapping(drv_tags, tags); + + while (!list_empty(&tags->page_list)) { + page = list_first_entry(&tags->page_list, struct page, lru); + list_del_init(&page->lru); + /* + * Remove kmemleak object previously allocated in + * blk_mq_alloc_rqs(). + */ + kmemleak_free(page_address(page)); + __free_pages(page, page->private); + } +} + +void blk_mq_free_rq_map(struct blk_mq_tags *tags) +{ + kfree(tags->rqs); + tags->rqs = NULL; + kfree(tags->static_rqs); + tags->static_rqs = NULL; + + blk_mq_free_tags(tags); +} + +static enum hctx_type hctx_idx_to_type(struct blk_mq_tag_set *set, + unsigned int hctx_idx) +{ + int i; + + for (i = 0; i < set->nr_maps; i++) { + unsigned int start = set->map[i].queue_offset; + unsigned int end = start + set->map[i].nr_queues; + + if (hctx_idx >= start && hctx_idx < end) + break; + } + + if (i >= set->nr_maps) + i = HCTX_TYPE_DEFAULT; + + return i; +} + +static int blk_mq_get_hctx_node(struct blk_mq_tag_set *set, + unsigned int hctx_idx) +{ + enum hctx_type type = hctx_idx_to_type(set, hctx_idx); + + return blk_mq_hw_queue_to_node(&set->map[type], hctx_idx); +} + +static struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, + unsigned int hctx_idx, + unsigned int nr_tags, + unsigned int reserved_tags) +{ + int node = blk_mq_get_hctx_node(set, hctx_idx); + struct blk_mq_tags *tags; + + if (node == NUMA_NO_NODE) + node = set->numa_node; + + tags = blk_mq_init_tags(nr_tags, reserved_tags, node, + BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags)); + if (!tags) + return NULL; + + tags->rqs = kcalloc_node(nr_tags, sizeof(struct request *), + GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, + node); + if (!tags->rqs) { + blk_mq_free_tags(tags); + return NULL; + } + + tags->static_rqs = kcalloc_node(nr_tags, sizeof(struct request *), + GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, + node); + if (!tags->static_rqs) { + kfree(tags->rqs); + blk_mq_free_tags(tags); + return NULL; + } + + return tags; +} + +static int blk_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, + unsigned int hctx_idx, int node) +{ + int ret; + + if (set->ops->init_request) { + ret = set->ops->init_request(set, rq, hctx_idx, node); + if (ret) + return ret; + } + + WRITE_ONCE(rq->state, MQ_RQ_IDLE); + return 0; +} + +static int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, + struct blk_mq_tags *tags, + unsigned int hctx_idx, unsigned int depth) +{ + unsigned int i, j, entries_per_page, max_order = 4; + int node = blk_mq_get_hctx_node(set, hctx_idx); + size_t rq_size, left; + + if (node == NUMA_NO_NODE) + node = set->numa_node; + + INIT_LIST_HEAD(&tags->page_list); + + /* + * rq_size is the size of the request plus driver payload, rounded + * to the cacheline size + */ + rq_size = round_up(sizeof(struct request) + set->cmd_size, + cache_line_size()); + left = rq_size * depth; + + for (i = 0; i < depth; ) { + int this_order = max_order; + struct page *page; + int to_do; + void *p; + + while (this_order && left < order_to_size(this_order - 1)) + this_order--; + + do { + page = alloc_pages_node(node, + GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO, + this_order); + if (page) + break; + if (!this_order--) + break; + if (order_to_size(this_order) < rq_size) + break; + } while (1); + + if (!page) + goto fail; + + page->private = this_order; + list_add_tail(&page->lru, &tags->page_list); + + p = page_address(page); + /* + * Allow kmemleak to scan these pages as they contain pointers + * to additional allocations like via ops->init_request(). + */ + kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO); + entries_per_page = order_to_size(this_order) / rq_size; + to_do = min(entries_per_page, depth - i); + left -= to_do * rq_size; + for (j = 0; j < to_do; j++) { + struct request *rq = p; + + tags->static_rqs[i] = rq; + if (blk_mq_init_request(set, rq, hctx_idx, node)) { + tags->static_rqs[i] = NULL; + goto fail; + } + + p += rq_size; + i++; + } + } + return 0; + +fail: + blk_mq_free_rqs(set, tags, hctx_idx); + return -ENOMEM; +} + +struct rq_iter_data { + struct blk_mq_hw_ctx *hctx; + bool has_rq; +}; + +static bool blk_mq_has_request(struct request *rq, void *data) +{ + struct rq_iter_data *iter_data = data; + + if (rq->mq_hctx != iter_data->hctx) + return true; + iter_data->has_rq = true; + return false; +} + +static bool blk_mq_hctx_has_requests(struct blk_mq_hw_ctx *hctx) +{ + struct blk_mq_tags *tags = hctx->sched_tags ? + hctx->sched_tags : hctx->tags; + struct rq_iter_data data = { + .hctx = hctx, + }; + + blk_mq_all_tag_iter(tags, blk_mq_has_request, &data); + return data.has_rq; +} + +static inline bool blk_mq_last_cpu_in_hctx(unsigned int cpu, + struct blk_mq_hw_ctx *hctx) +{ + if (cpumask_first_and(hctx->cpumask, cpu_online_mask) != cpu) + return false; + if (cpumask_next_and(cpu, hctx->cpumask, cpu_online_mask) < nr_cpu_ids) + return false; + return true; +} + +static int blk_mq_hctx_notify_offline(unsigned int cpu, struct hlist_node *node) +{ + struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node, + struct blk_mq_hw_ctx, cpuhp_online); + + if (!cpumask_test_cpu(cpu, hctx->cpumask) || + !blk_mq_last_cpu_in_hctx(cpu, hctx)) + return 0; + + /* + * Prevent new request from being allocated on the current hctx. + * + * The smp_mb__after_atomic() Pairs with the implied barrier in + * test_and_set_bit_lock in sbitmap_get(). Ensures the inactive flag is + * seen once we return from the tag allocator. + */ + set_bit(BLK_MQ_S_INACTIVE, &hctx->state); + smp_mb__after_atomic(); + + /* + * Try to grab a reference to the queue and wait for any outstanding + * requests. If we could not grab a reference the queue has been + * frozen and there are no requests. + */ + if (percpu_ref_tryget(&hctx->queue->q_usage_counter)) { + while (blk_mq_hctx_has_requests(hctx)) + msleep(5); + percpu_ref_put(&hctx->queue->q_usage_counter); + } + + return 0; +} + +static int blk_mq_hctx_notify_online(unsigned int cpu, struct hlist_node *node) +{ + struct blk_mq_hw_ctx *hctx = hlist_entry_safe(node, + struct blk_mq_hw_ctx, cpuhp_online); + + if (cpumask_test_cpu(cpu, hctx->cpumask)) + clear_bit(BLK_MQ_S_INACTIVE, &hctx->state); + return 0; +} + +/* + * 'cpu' is going away. splice any existing rq_list entries from this + * software queue to the hw queue dispatch list, and ensure that it + * gets run. + */ +static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node) +{ + struct blk_mq_hw_ctx *hctx; + struct blk_mq_ctx *ctx; + LIST_HEAD(tmp); + enum hctx_type type; + + hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead); + if (!cpumask_test_cpu(cpu, hctx->cpumask)) + return 0; + + ctx = __blk_mq_get_ctx(hctx->queue, cpu); + type = hctx->type; + + spin_lock(&ctx->lock); + if (!list_empty(&ctx->rq_lists[type])) { + list_splice_init(&ctx->rq_lists[type], &tmp); + blk_mq_hctx_clear_pending(hctx, ctx); + } + spin_unlock(&ctx->lock); + + if (list_empty(&tmp)) + return 0; + + spin_lock(&hctx->lock); + list_splice_tail_init(&tmp, &hctx->dispatch); + spin_unlock(&hctx->lock); + + blk_mq_run_hw_queue(hctx, true); + return 0; +} + +static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx) +{ + if (!(hctx->flags & BLK_MQ_F_STACKING)) + cpuhp_state_remove_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE, + &hctx->cpuhp_online); + cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD, + &hctx->cpuhp_dead); +} + +/* + * Before freeing hw queue, clearing the flush request reference in + * tags->rqs[] for avoiding potential UAF. + */ +static void blk_mq_clear_flush_rq_mapping(struct blk_mq_tags *tags, + unsigned int queue_depth, struct request *flush_rq) +{ + int i; + unsigned long flags; + + /* The hw queue may not be mapped yet */ + if (!tags) + return; + + WARN_ON_ONCE(req_ref_read(flush_rq) != 0); + + for (i = 0; i < queue_depth; i++) + cmpxchg(&tags->rqs[i], flush_rq, NULL); + + /* + * Wait until all pending iteration is done. + * + * Request reference is cleared and it is guaranteed to be observed + * after the ->lock is released. + */ + spin_lock_irqsave(&tags->lock, flags); + spin_unlock_irqrestore(&tags->lock, flags); +} + +/* hctx->ctxs will be freed in queue's release handler */ +static void blk_mq_exit_hctx(struct request_queue *q, + struct blk_mq_tag_set *set, + struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) +{ + struct request *flush_rq = hctx->fq->flush_rq; + + if (blk_mq_hw_queue_mapped(hctx)) + blk_mq_tag_idle(hctx); + + if (blk_queue_init_done(q)) + blk_mq_clear_flush_rq_mapping(set->tags[hctx_idx], + set->queue_depth, flush_rq); + if (set->ops->exit_request) + set->ops->exit_request(set, flush_rq, hctx_idx); + + if (set->ops->exit_hctx) + set->ops->exit_hctx(hctx, hctx_idx); + + blk_mq_remove_cpuhp(hctx); + + xa_erase(&q->hctx_table, hctx_idx); + + spin_lock(&q->unused_hctx_lock); + list_add(&hctx->hctx_list, &q->unused_hctx_list); + spin_unlock(&q->unused_hctx_lock); +} + +static void blk_mq_exit_hw_queues(struct request_queue *q, + struct blk_mq_tag_set *set, int nr_queue) +{ + struct blk_mq_hw_ctx *hctx; + unsigned long i; + + queue_for_each_hw_ctx(q, hctx, i) { + if (i == nr_queue) + break; + blk_mq_exit_hctx(q, set, hctx, i); + } +} + +static int blk_mq_init_hctx(struct request_queue *q, + struct blk_mq_tag_set *set, + struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) +{ + hctx->queue_num = hctx_idx; + + if (!(hctx->flags & BLK_MQ_F_STACKING)) + cpuhp_state_add_instance_nocalls(CPUHP_AP_BLK_MQ_ONLINE, + &hctx->cpuhp_online); + cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead); + + hctx->tags = set->tags[hctx_idx]; + + if (set->ops->init_hctx && + set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) + goto unregister_cpu_notifier; + + if (blk_mq_init_request(set, hctx->fq->flush_rq, hctx_idx, + hctx->numa_node)) + goto exit_hctx; + + if (xa_insert(&q->hctx_table, hctx_idx, hctx, GFP_KERNEL)) + goto exit_flush_rq; + + return 0; + + exit_flush_rq: + if (set->ops->exit_request) + set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx); + exit_hctx: + if (set->ops->exit_hctx) + set->ops->exit_hctx(hctx, hctx_idx); + unregister_cpu_notifier: + blk_mq_remove_cpuhp(hctx); + return -1; +} + +static struct blk_mq_hw_ctx * +blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set, + int node) +{ + struct blk_mq_hw_ctx *hctx; + gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY; + + hctx = kzalloc_node(sizeof(struct blk_mq_hw_ctx), gfp, node); + if (!hctx) + goto fail_alloc_hctx; + + if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node)) + goto free_hctx; + + atomic_set(&hctx->nr_active, 0); + if (node == NUMA_NO_NODE) + node = set->numa_node; + hctx->numa_node = node; + + INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); + spin_lock_init(&hctx->lock); + INIT_LIST_HEAD(&hctx->dispatch); + hctx->queue = q; + hctx->flags = set->flags & ~BLK_MQ_F_TAG_QUEUE_SHARED; + + INIT_LIST_HEAD(&hctx->hctx_list); + + /* + * Allocate space for all possible cpus to avoid allocation at + * runtime + */ + hctx->ctxs = kmalloc_array_node(nr_cpu_ids, sizeof(void *), + gfp, node); + if (!hctx->ctxs) + goto free_cpumask; + + if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), + gfp, node, false, false)) + goto free_ctxs; + hctx->nr_ctx = 0; + + spin_lock_init(&hctx->dispatch_wait_lock); + init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake); + INIT_LIST_HEAD(&hctx->dispatch_wait.entry); + + hctx->fq = blk_alloc_flush_queue(hctx->numa_node, set->cmd_size, gfp); + if (!hctx->fq) + goto free_bitmap; + + blk_mq_hctx_kobj_init(hctx); + + return hctx; + + free_bitmap: + sbitmap_free(&hctx->ctx_map); + free_ctxs: + kfree(hctx->ctxs); + free_cpumask: + free_cpumask_var(hctx->cpumask); + free_hctx: + kfree(hctx); + fail_alloc_hctx: + return NULL; +} + +static void blk_mq_init_cpu_queues(struct request_queue *q, + unsigned int nr_hw_queues) +{ + struct blk_mq_tag_set *set = q->tag_set; + unsigned int i, j; + + for_each_possible_cpu(i) { + struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); + struct blk_mq_hw_ctx *hctx; + int k; + + __ctx->cpu = i; + spin_lock_init(&__ctx->lock); + for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++) + INIT_LIST_HEAD(&__ctx->rq_lists[k]); + + __ctx->queue = q; + + /* + * Set local node, IFF we have more than one hw queue. If + * not, we remain on the home node of the device + */ + for (j = 0; j < set->nr_maps; j++) { + hctx = blk_mq_map_queue_type(q, j, i); + if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) + hctx->numa_node = cpu_to_node(i); + } + } +} + +struct blk_mq_tags *blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set, + unsigned int hctx_idx, + unsigned int depth) +{ + struct blk_mq_tags *tags; + int ret; + + tags = blk_mq_alloc_rq_map(set, hctx_idx, depth, set->reserved_tags); + if (!tags) + return NULL; + + ret = blk_mq_alloc_rqs(set, tags, hctx_idx, depth); + if (ret) { + blk_mq_free_rq_map(tags); + return NULL; + } + + return tags; +} + +static bool __blk_mq_alloc_map_and_rqs(struct blk_mq_tag_set *set, + int hctx_idx) +{ + if (blk_mq_is_shared_tags(set->flags)) { + set->tags[hctx_idx] = set->shared_tags; + + return true; + } + + set->tags[hctx_idx] = blk_mq_alloc_map_and_rqs(set, hctx_idx, + set->queue_depth); + + return set->tags[hctx_idx]; +} + +void blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set, + struct blk_mq_tags *tags, + unsigned int hctx_idx) +{ + if (tags) { + blk_mq_free_rqs(set, tags, hctx_idx); + blk_mq_free_rq_map(tags); + } +} + +static void __blk_mq_free_map_and_rqs(struct blk_mq_tag_set *set, + unsigned int hctx_idx) +{ + if (!blk_mq_is_shared_tags(set->flags)) + blk_mq_free_map_and_rqs(set, set->tags[hctx_idx], hctx_idx); + + set->tags[hctx_idx] = NULL; +} + +static void blk_mq_map_swqueue(struct request_queue *q) +{ + unsigned int j, hctx_idx; + unsigned long i; + struct blk_mq_hw_ctx *hctx; + struct blk_mq_ctx *ctx; + struct blk_mq_tag_set *set = q->tag_set; + + queue_for_each_hw_ctx(q, hctx, i) { + cpumask_clear(hctx->cpumask); + hctx->nr_ctx = 0; + hctx->dispatch_from = NULL; + } + + /* + * Map software to hardware queues. + * + * If the cpu isn't present, the cpu is mapped to first hctx. + */ + for_each_possible_cpu(i) { + + ctx = per_cpu_ptr(q->queue_ctx, i); + for (j = 0; j < set->nr_maps; j++) { + if (!set->map[j].nr_queues) { + ctx->hctxs[j] = blk_mq_map_queue_type(q, + HCTX_TYPE_DEFAULT, i); + continue; + } + hctx_idx = set->map[j].mq_map[i]; + /* unmapped hw queue can be remapped after CPU topo changed */ + if (!set->tags[hctx_idx] && + !__blk_mq_alloc_map_and_rqs(set, hctx_idx)) { + /* + * If tags initialization fail for some hctx, + * that hctx won't be brought online. In this + * case, remap the current ctx to hctx[0] which + * is guaranteed to always have tags allocated + */ + set->map[j].mq_map[i] = 0; + } + + hctx = blk_mq_map_queue_type(q, j, i); + ctx->hctxs[j] = hctx; + /* + * If the CPU is already set in the mask, then we've + * mapped this one already. This can happen if + * devices share queues across queue maps. + */ + if (cpumask_test_cpu(i, hctx->cpumask)) + continue; + + cpumask_set_cpu(i, hctx->cpumask); + hctx->type = j; + ctx->index_hw[hctx->type] = hctx->nr_ctx; + hctx->ctxs[hctx->nr_ctx++] = ctx; + + /* + * If the nr_ctx type overflows, we have exceeded the + * amount of sw queues we can support. + */ + BUG_ON(!hctx->nr_ctx); + } + + for (; j < HCTX_MAX_TYPES; j++) + ctx->hctxs[j] = blk_mq_map_queue_type(q, + HCTX_TYPE_DEFAULT, i); + } + + queue_for_each_hw_ctx(q, hctx, i) { + /* + * If no software queues are mapped to this hardware queue, + * disable it and free the request entries. + */ + if (!hctx->nr_ctx) { + /* Never unmap queue 0. We need it as a + * fallback in case of a new remap fails + * allocation + */ + if (i) + __blk_mq_free_map_and_rqs(set, i); + + hctx->tags = NULL; + continue; + } + + hctx->tags = set->tags[i]; + WARN_ON(!hctx->tags); + + /* + * Set the map size to the number of mapped software queues. + * This is more accurate and more efficient than looping + * over all possibly mapped software queues. + */ + sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx); + + /* + * Initialize batch roundrobin counts + */ + hctx->next_cpu = blk_mq_first_mapped_cpu(hctx); + hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; + } +} + +/* + * Caller needs to ensure that we're either frozen/quiesced, or that + * the queue isn't live yet. + */ +static void queue_set_hctx_shared(struct request_queue *q, bool shared) +{ + struct blk_mq_hw_ctx *hctx; + unsigned long i; + + queue_for_each_hw_ctx(q, hctx, i) { + if (shared) { + hctx->flags |= BLK_MQ_F_TAG_QUEUE_SHARED; + } else { + blk_mq_tag_idle(hctx); + hctx->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED; + } + } +} + +static void blk_mq_update_tag_set_shared(struct blk_mq_tag_set *set, + bool shared) +{ + struct request_queue *q; + + lockdep_assert_held(&set->tag_list_lock); + + list_for_each_entry(q, &set->tag_list, tag_set_list) { + blk_mq_freeze_queue(q); + queue_set_hctx_shared(q, shared); + blk_mq_unfreeze_queue(q); + } +} + +static void blk_mq_del_queue_tag_set(struct request_queue *q) +{ + struct blk_mq_tag_set *set = q->tag_set; + + mutex_lock(&set->tag_list_lock); + list_del(&q->tag_set_list); + if (list_is_singular(&set->tag_list)) { + /* just transitioned to unshared */ + set->flags &= ~BLK_MQ_F_TAG_QUEUE_SHARED; + /* update existing queue */ + blk_mq_update_tag_set_shared(set, false); + } + mutex_unlock(&set->tag_list_lock); + INIT_LIST_HEAD(&q->tag_set_list); +} + +static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set, + struct request_queue *q) +{ + mutex_lock(&set->tag_list_lock); + + /* + * Check to see if we're transitioning to shared (from 1 to 2 queues). + */ + if (!list_empty(&set->tag_list) && + !(set->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) { + set->flags |= BLK_MQ_F_TAG_QUEUE_SHARED; + /* update existing queue */ + blk_mq_update_tag_set_shared(set, true); + } + if (set->flags & BLK_MQ_F_TAG_QUEUE_SHARED) + queue_set_hctx_shared(q, true); + list_add_tail(&q->tag_set_list, &set->tag_list); + + mutex_unlock(&set->tag_list_lock); +} + +/* All allocations will be freed in release handler of q->mq_kobj */ +static int blk_mq_alloc_ctxs(struct request_queue *q) +{ + struct blk_mq_ctxs *ctxs; + int cpu; + + ctxs = kzalloc(sizeof(*ctxs), GFP_KERNEL); + if (!ctxs) + return -ENOMEM; + + ctxs->queue_ctx = alloc_percpu(struct blk_mq_ctx); + if (!ctxs->queue_ctx) + goto fail; + + for_each_possible_cpu(cpu) { + struct blk_mq_ctx *ctx = per_cpu_ptr(ctxs->queue_ctx, cpu); + ctx->ctxs = ctxs; + } + + q->mq_kobj = &ctxs->kobj; + q->queue_ctx = ctxs->queue_ctx; + + return 0; + fail: + kfree(ctxs); + return -ENOMEM; +} + +/* + * It is the actual release handler for mq, but we do it from + * request queue's release handler for avoiding use-after-free + * and headache because q->mq_kobj shouldn't have been introduced, + * but we can't group ctx/kctx kobj without it. + */ +void blk_mq_release(struct request_queue *q) +{ + struct blk_mq_hw_ctx *hctx, *next; + unsigned long i; + + queue_for_each_hw_ctx(q, hctx, i) + WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list)); + + /* all hctx are in .unused_hctx_list now */ + list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) { + list_del_init(&hctx->hctx_list); + kobject_put(&hctx->kobj); + } + + xa_destroy(&q->hctx_table); + + /* + * release .mq_kobj and sw queue's kobject now because + * both share lifetime with request queue. + */ + blk_mq_sysfs_deinit(q); +} + +static struct request_queue *blk_mq_init_queue_data(struct blk_mq_tag_set *set, + void *queuedata) +{ + struct request_queue *q; + int ret; + + q = blk_alloc_queue(set->numa_node, set->flags & BLK_MQ_F_BLOCKING); + if (!q) + return ERR_PTR(-ENOMEM); + q->queuedata = queuedata; + ret = blk_mq_init_allocated_queue(set, q); + if (ret) { + blk_put_queue(q); + return ERR_PTR(ret); + } + return q; +} + +struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) +{ + return blk_mq_init_queue_data(set, NULL); +} +EXPORT_SYMBOL(blk_mq_init_queue); + +/** + * blk_mq_destroy_queue - shutdown a request queue + * @q: request queue to shutdown + * + * This shuts down a request queue allocated by blk_mq_init_queue() and drops + * the initial reference. All future requests will failed with -ENODEV. + * + * Context: can sleep + */ +void blk_mq_destroy_queue(struct request_queue *q) +{ + WARN_ON_ONCE(!queue_is_mq(q)); + WARN_ON_ONCE(blk_queue_registered(q)); + + might_sleep(); + + blk_queue_flag_set(QUEUE_FLAG_DYING, q); + blk_queue_start_drain(q); + blk_freeze_queue(q); + + blk_sync_queue(q); + blk_mq_cancel_work_sync(q); + blk_mq_exit_queue(q); + + /* @q is and will stay empty, shutdown and put */ + blk_put_queue(q); +} +EXPORT_SYMBOL(blk_mq_destroy_queue); + +struct gendisk *__blk_mq_alloc_disk(struct blk_mq_tag_set *set, void *queuedata, + struct lock_class_key *lkclass) +{ + struct request_queue *q; + struct gendisk *disk; + + q = blk_mq_init_queue_data(set, queuedata); + if (IS_ERR(q)) + return ERR_CAST(q); + + disk = __alloc_disk_node(q, set->numa_node, lkclass); + if (!disk) { + blk_mq_destroy_queue(q); + return ERR_PTR(-ENOMEM); + } + set_bit(GD_OWNS_QUEUE, &disk->state); + return disk; +} +EXPORT_SYMBOL(__blk_mq_alloc_disk); + +struct gendisk *blk_mq_alloc_disk_for_queue(struct request_queue *q, + struct lock_class_key *lkclass) +{ + struct gendisk *disk; + + if (!blk_get_queue(q)) + return NULL; + disk = __alloc_disk_node(q, NUMA_NO_NODE, lkclass); + if (!disk) + blk_put_queue(q); + return disk; +} +EXPORT_SYMBOL(blk_mq_alloc_disk_for_queue); + +static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx( + struct blk_mq_tag_set *set, struct request_queue *q, + int hctx_idx, int node) +{ + struct blk_mq_hw_ctx *hctx = NULL, *tmp; + + /* reuse dead hctx first */ + spin_lock(&q->unused_hctx_lock); + list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) { + if (tmp->numa_node == node) { + hctx = tmp; + break; + } + } + if (hctx) + list_del_init(&hctx->hctx_list); + spin_unlock(&q->unused_hctx_lock); + + if (!hctx) + hctx = blk_mq_alloc_hctx(q, set, node); + if (!hctx) + goto fail; + + if (blk_mq_init_hctx(q, set, hctx, hctx_idx)) + goto free_hctx; + + return hctx; + + free_hctx: + kobject_put(&hctx->kobj); + fail: + return NULL; +} + +static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, + struct request_queue *q) +{ + struct blk_mq_hw_ctx *hctx; + unsigned long i, j; + + /* protect against switching io scheduler */ + mutex_lock(&q->sysfs_lock); + for (i = 0; i < set->nr_hw_queues; i++) { + int old_node; + int node = blk_mq_get_hctx_node(set, i); + struct blk_mq_hw_ctx *old_hctx = xa_load(&q->hctx_table, i); + + if (old_hctx) { + old_node = old_hctx->numa_node; + blk_mq_exit_hctx(q, set, old_hctx, i); + } + + if (!blk_mq_alloc_and_init_hctx(set, q, i, node)) { + if (!old_hctx) + break; + pr_warn("Allocate new hctx on node %d fails, fallback to previous one on node %d\n", + node, old_node); + hctx = blk_mq_alloc_and_init_hctx(set, q, i, old_node); + WARN_ON_ONCE(!hctx); + } + } + /* + * Increasing nr_hw_queues fails. Free the newly allocated + * hctxs and keep the previous q->nr_hw_queues. + */ + if (i != set->nr_hw_queues) { + j = q->nr_hw_queues; + } else { + j = i; + q->nr_hw_queues = set->nr_hw_queues; + } + + xa_for_each_start(&q->hctx_table, j, hctx, j) + blk_mq_exit_hctx(q, set, hctx, j); + mutex_unlock(&q->sysfs_lock); +} + +static void blk_mq_update_poll_flag(struct request_queue *q) +{ + struct blk_mq_tag_set *set = q->tag_set; + + if (set->nr_maps > HCTX_TYPE_POLL && + set->map[HCTX_TYPE_POLL].nr_queues) + blk_queue_flag_set(QUEUE_FLAG_POLL, q); + else + blk_queue_flag_clear(QUEUE_FLAG_POLL, q); +} + +int blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, + struct request_queue *q) +{ + WARN_ON_ONCE(blk_queue_has_srcu(q) != + !!(set->flags & BLK_MQ_F_BLOCKING)); + + /* mark the queue as mq asap */ + q->mq_ops = set->ops; + + q->poll_cb = blk_stat_alloc_callback(blk_mq_poll_stats_fn, + blk_mq_poll_stats_bkt, + BLK_MQ_POLL_STATS_BKTS, q); + if (!q->poll_cb) + goto err_exit; + + if (blk_mq_alloc_ctxs(q)) + goto err_poll; + + /* init q->mq_kobj and sw queues' kobjects */ + blk_mq_sysfs_init(q); + + INIT_LIST_HEAD(&q->unused_hctx_list); + spin_lock_init(&q->unused_hctx_lock); + + xa_init(&q->hctx_table); + + blk_mq_realloc_hw_ctxs(set, q); + if (!q->nr_hw_queues) + goto err_hctxs; + + INIT_WORK(&q->timeout_work, blk_mq_timeout_work); + blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); + + q->tag_set = set; + + q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; + blk_mq_update_poll_flag(q); + + INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work); + INIT_LIST_HEAD(&q->requeue_list); + spin_lock_init(&q->requeue_lock); + + q->nr_requests = set->queue_depth; + + /* + * Default to classic polling + */ + q->poll_nsec = BLK_MQ_POLL_CLASSIC; + + blk_mq_init_cpu_queues(q, set->nr_hw_queues); + blk_mq_add_queue_tag_set(set, q); + blk_mq_map_swqueue(q); + return 0; + +err_hctxs: + blk_mq_release(q); +err_poll: + blk_stat_free_callback(q->poll_cb); + q->poll_cb = NULL; +err_exit: + q->mq_ops = NULL; + return -ENOMEM; +} +EXPORT_SYMBOL(blk_mq_init_allocated_queue); + +/* tags can _not_ be used after returning from blk_mq_exit_queue */ +void blk_mq_exit_queue(struct request_queue *q) +{ + struct blk_mq_tag_set *set = q->tag_set; + + /* Checks hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED. */ + blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); + /* May clear BLK_MQ_F_TAG_QUEUE_SHARED in hctx->flags. */ + blk_mq_del_queue_tag_set(q); +} + +static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) +{ + int i; + + if (blk_mq_is_shared_tags(set->flags)) { + set->shared_tags = blk_mq_alloc_map_and_rqs(set, + BLK_MQ_NO_HCTX_IDX, + set->queue_depth); + if (!set->shared_tags) + return -ENOMEM; + } + + for (i = 0; i < set->nr_hw_queues; i++) { + if (!__blk_mq_alloc_map_and_rqs(set, i)) + goto out_unwind; + cond_resched(); + } + + return 0; + +out_unwind: + while (--i >= 0) + __blk_mq_free_map_and_rqs(set, i); + + if (blk_mq_is_shared_tags(set->flags)) { + blk_mq_free_map_and_rqs(set, set->shared_tags, + BLK_MQ_NO_HCTX_IDX); + } + + return -ENOMEM; +} + +/* + * Allocate the request maps associated with this tag_set. Note that this + * may reduce the depth asked for, if memory is tight. set->queue_depth + * will be updated to reflect the allocated depth. + */ +static int blk_mq_alloc_set_map_and_rqs(struct blk_mq_tag_set *set) +{ + unsigned int depth; + int err; + + depth = set->queue_depth; + do { + err = __blk_mq_alloc_rq_maps(set); + if (!err) + break; + + set->queue_depth >>= 1; + if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { + err = -ENOMEM; + break; + } + } while (set->queue_depth); + + if (!set->queue_depth || err) { + pr_err("blk-mq: failed to allocate request map\n"); + return -ENOMEM; + } + + if (depth != set->queue_depth) + pr_info("blk-mq: reduced tag depth (%u -> %u)\n", + depth, set->queue_depth); + + return 0; +} + +static void blk_mq_update_queue_map(struct blk_mq_tag_set *set) +{ + /* + * blk_mq_map_queues() and multiple .map_queues() implementations + * expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the + * number of hardware queues. + */ + if (set->nr_maps == 1) + set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues; + + if (set->ops->map_queues && !is_kdump_kernel()) { + int i; + + /* + * transport .map_queues is usually done in the following + * way: + * + * for (queue = 0; queue < set->nr_hw_queues; queue++) { + * mask = get_cpu_mask(queue) + * for_each_cpu(cpu, mask) + * set->map[x].mq_map[cpu] = queue; + * } + * + * When we need to remap, the table has to be cleared for + * killing stale mapping since one CPU may not be mapped + * to any hw queue. + */ + for (i = 0; i < set->nr_maps; i++) + blk_mq_clear_mq_map(&set->map[i]); + + set->ops->map_queues(set); + } else { + BUG_ON(set->nr_maps > 1); + blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); + } +} + +static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set, + int cur_nr_hw_queues, int new_nr_hw_queues) +{ + struct blk_mq_tags **new_tags; + + if (cur_nr_hw_queues >= new_nr_hw_queues) + return 0; + + new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *), + GFP_KERNEL, set->numa_node); + if (!new_tags) + return -ENOMEM; + + if (set->tags) + memcpy(new_tags, set->tags, cur_nr_hw_queues * + sizeof(*set->tags)); + kfree(set->tags); + set->tags = new_tags; + set->nr_hw_queues = new_nr_hw_queues; + + return 0; +} + +static int blk_mq_alloc_tag_set_tags(struct blk_mq_tag_set *set, + int new_nr_hw_queues) +{ + return blk_mq_realloc_tag_set_tags(set, 0, new_nr_hw_queues); +} + +/* + * Alloc a tag set to be associated with one or more request queues. + * May fail with EINVAL for various error conditions. May adjust the + * requested depth down, if it's too large. In that case, the set + * value will be stored in set->queue_depth. + */ +int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set) +{ + int i, ret; + + BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS); + + if (!set->nr_hw_queues) + return -EINVAL; + if (!set->queue_depth) + return -EINVAL; + if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) + return -EINVAL; + + if (!set->ops->queue_rq) + return -EINVAL; + + if (!set->ops->get_budget ^ !set->ops->put_budget) + return -EINVAL; + + if (set->queue_depth > BLK_MQ_MAX_DEPTH) { + pr_info("blk-mq: reduced tag depth to %u\n", + BLK_MQ_MAX_DEPTH); + set->queue_depth = BLK_MQ_MAX_DEPTH; + } + + if (!set->nr_maps) + set->nr_maps = 1; + else if (set->nr_maps > HCTX_MAX_TYPES) + return -EINVAL; + + /* + * If a crashdump is active, then we are potentially in a very + * memory constrained environment. Limit us to 1 queue and + * 64 tags to prevent using too much memory. + */ + if (is_kdump_kernel()) { + set->nr_hw_queues = 1; + set->nr_maps = 1; + set->queue_depth = min(64U, set->queue_depth); + } + /* + * There is no use for more h/w queues than cpus if we just have + * a single map + */ + if (set->nr_maps == 1 && set->nr_hw_queues > nr_cpu_ids) + set->nr_hw_queues = nr_cpu_ids; + + if (blk_mq_alloc_tag_set_tags(set, set->nr_hw_queues) < 0) + return -ENOMEM; + + ret = -ENOMEM; + for (i = 0; i < set->nr_maps; i++) { + set->map[i].mq_map = kcalloc_node(nr_cpu_ids, + sizeof(set->map[i].mq_map[0]), + GFP_KERNEL, set->numa_node); + if (!set->map[i].mq_map) + goto out_free_mq_map; + set->map[i].nr_queues = is_kdump_kernel() ? 1 : set->nr_hw_queues; + } + + blk_mq_update_queue_map(set); + + ret = blk_mq_alloc_set_map_and_rqs(set); + if (ret) + goto out_free_mq_map; + + mutex_init(&set->tag_list_lock); + INIT_LIST_HEAD(&set->tag_list); + + return 0; + +out_free_mq_map: + for (i = 0; i < set->nr_maps; i++) { + kfree(set->map[i].mq_map); + set->map[i].mq_map = NULL; + } + kfree(set->tags); + set->tags = NULL; + return ret; +} +EXPORT_SYMBOL(blk_mq_alloc_tag_set); + +/* allocate and initialize a tagset for a simple single-queue device */ +int blk_mq_alloc_sq_tag_set(struct blk_mq_tag_set *set, + const struct blk_mq_ops *ops, unsigned int queue_depth, + unsigned int set_flags) +{ + memset(set, 0, sizeof(*set)); + set->ops = ops; + set->nr_hw_queues = 1; + set->nr_maps = 1; + set->queue_depth = queue_depth; + set->numa_node = NUMA_NO_NODE; + set->flags = set_flags; + return blk_mq_alloc_tag_set(set); +} +EXPORT_SYMBOL_GPL(blk_mq_alloc_sq_tag_set); + +void blk_mq_free_tag_set(struct blk_mq_tag_set *set) +{ + int i, j; + + for (i = 0; i < set->nr_hw_queues; i++) + __blk_mq_free_map_and_rqs(set, i); + + if (blk_mq_is_shared_tags(set->flags)) { + blk_mq_free_map_and_rqs(set, set->shared_tags, + BLK_MQ_NO_HCTX_IDX); + } + + for (j = 0; j < set->nr_maps; j++) { + kfree(set->map[j].mq_map); + set->map[j].mq_map = NULL; + } + + kfree(set->tags); + set->tags = NULL; +} +EXPORT_SYMBOL(blk_mq_free_tag_set); + +int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) +{ + struct blk_mq_tag_set *set = q->tag_set; + struct blk_mq_hw_ctx *hctx; + int ret; + unsigned long i; + + if (!set) + return -EINVAL; + + if (q->nr_requests == nr) + return 0; + + blk_mq_freeze_queue(q); + blk_mq_quiesce_queue(q); + + ret = 0; + queue_for_each_hw_ctx(q, hctx, i) { + if (!hctx->tags) + continue; + /* + * If we're using an MQ scheduler, just update the scheduler + * queue depth. This is similar to what the old code would do. + */ + if (hctx->sched_tags) { + ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags, + nr, true); + } else { + ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr, + false); + } + if (ret) + break; + if (q->elevator && q->elevator->type->ops.depth_updated) + q->elevator->type->ops.depth_updated(hctx); + } + if (!ret) { + q->nr_requests = nr; + if (blk_mq_is_shared_tags(set->flags)) { + if (q->elevator) + blk_mq_tag_update_sched_shared_tags(q); + else + blk_mq_tag_resize_shared_tags(set, nr); + } + } + + blk_mq_unquiesce_queue(q); + blk_mq_unfreeze_queue(q); + + return ret; +} + +/* + * request_queue and elevator_type pair. + * It is just used by __blk_mq_update_nr_hw_queues to cache + * the elevator_type associated with a request_queue. + */ +struct blk_mq_qe_pair { + struct list_head node; + struct request_queue *q; + struct elevator_type *type; +}; + +/* + * Cache the elevator_type in qe pair list and switch the + * io scheduler to 'none' + */ +static bool blk_mq_elv_switch_none(struct list_head *head, + struct request_queue *q) +{ + struct blk_mq_qe_pair *qe; + + if (!q->elevator) + return true; + + qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY); + if (!qe) + return false; + + /* q->elevator needs protection from ->sysfs_lock */ + mutex_lock(&q->sysfs_lock); + + INIT_LIST_HEAD(&qe->node); + qe->q = q; + qe->type = q->elevator->type; + list_add(&qe->node, head); + + /* + * After elevator_switch, the previous elevator_queue will be + * released by elevator_release. The reference of the io scheduler + * module get by elevator_get will also be put. So we need to get + * a reference of the io scheduler module here to prevent it to be + * removed. + */ + __module_get(qe->type->elevator_owner); + elevator_switch(q, NULL); + mutex_unlock(&q->sysfs_lock); + + return true; +} + +static struct blk_mq_qe_pair *blk_lookup_qe_pair(struct list_head *head, + struct request_queue *q) +{ + struct blk_mq_qe_pair *qe; + + list_for_each_entry(qe, head, node) + if (qe->q == q) + return qe; + + return NULL; +} + +static void blk_mq_elv_switch_back(struct list_head *head, + struct request_queue *q) +{ + struct blk_mq_qe_pair *qe; + struct elevator_type *t; + + qe = blk_lookup_qe_pair(head, q); + if (!qe) + return; + t = qe->type; + list_del(&qe->node); + kfree(qe); + + mutex_lock(&q->sysfs_lock); + elevator_switch(q, t); + mutex_unlock(&q->sysfs_lock); +} + +static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, + int nr_hw_queues) +{ + struct request_queue *q; + LIST_HEAD(head); + int prev_nr_hw_queues; + + lockdep_assert_held(&set->tag_list_lock); + + if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids) + nr_hw_queues = nr_cpu_ids; + if (nr_hw_queues < 1) + return; + if (set->nr_maps == 1 && nr_hw_queues == set->nr_hw_queues) + return; + + list_for_each_entry(q, &set->tag_list, tag_set_list) + blk_mq_freeze_queue(q); + /* + * Switch IO scheduler to 'none', cleaning up the data associated + * with the previous scheduler. We will switch back once we are done + * updating the new sw to hw queue mappings. + */ + list_for_each_entry(q, &set->tag_list, tag_set_list) + if (!blk_mq_elv_switch_none(&head, q)) + goto switch_back; + + list_for_each_entry(q, &set->tag_list, tag_set_list) { + blk_mq_debugfs_unregister_hctxs(q); + blk_mq_sysfs_unregister_hctxs(q); + } + + prev_nr_hw_queues = set->nr_hw_queues; + if (blk_mq_realloc_tag_set_tags(set, set->nr_hw_queues, nr_hw_queues) < + 0) + goto reregister; + + set->nr_hw_queues = nr_hw_queues; +fallback: + blk_mq_update_queue_map(set); + list_for_each_entry(q, &set->tag_list, tag_set_list) { + blk_mq_realloc_hw_ctxs(set, q); + blk_mq_update_poll_flag(q); + if (q->nr_hw_queues != set->nr_hw_queues) { + int i = prev_nr_hw_queues; + + pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n", + nr_hw_queues, prev_nr_hw_queues); + for (; i < set->nr_hw_queues; i++) + __blk_mq_free_map_and_rqs(set, i); + + set->nr_hw_queues = prev_nr_hw_queues; + blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); + goto fallback; + } + blk_mq_map_swqueue(q); + } + +reregister: + list_for_each_entry(q, &set->tag_list, tag_set_list) { + blk_mq_sysfs_register_hctxs(q); + blk_mq_debugfs_register_hctxs(q); + } + +switch_back: + list_for_each_entry(q, &set->tag_list, tag_set_list) + blk_mq_elv_switch_back(&head, q); + + list_for_each_entry(q, &set->tag_list, tag_set_list) + blk_mq_unfreeze_queue(q); +} + +void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) +{ + mutex_lock(&set->tag_list_lock); + __blk_mq_update_nr_hw_queues(set, nr_hw_queues); + mutex_unlock(&set->tag_list_lock); +} +EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); + +/* Enable polling stats and return whether they were already enabled. */ +static bool blk_poll_stats_enable(struct request_queue *q) +{ + if (q->poll_stat) + return true; + + return blk_stats_alloc_enable(q); +} + +static void blk_mq_poll_stats_start(struct request_queue *q) +{ + /* + * We don't arm the callback if polling stats are not enabled or the + * callback is already active. + */ + if (!q->poll_stat || blk_stat_is_active(q->poll_cb)) + return; + + blk_stat_activate_msecs(q->poll_cb, 100); +} + +static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb) +{ + struct request_queue *q = cb->data; + int bucket; + + for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) { + if (cb->stat[bucket].nr_samples) + q->poll_stat[bucket] = cb->stat[bucket]; + } +} + +static unsigned long blk_mq_poll_nsecs(struct request_queue *q, + struct request *rq) +{ + unsigned long ret = 0; + int bucket; + + /* + * If stats collection isn't on, don't sleep but turn it on for + * future users + */ + if (!blk_poll_stats_enable(q)) + return 0; + + /* + * As an optimistic guess, use half of the mean service time + * for this type of request. We can (and should) make this smarter. + * For instance, if the completion latencies are tight, we can + * get closer than just half the mean. This is especially + * important on devices where the completion latencies are longer + * than ~10 usec. We do use the stats for the relevant IO size + * if available which does lead to better estimates. + */ + bucket = blk_mq_poll_stats_bkt(rq); + if (bucket < 0) + return ret; + + if (q->poll_stat[bucket].nr_samples) + ret = (q->poll_stat[bucket].mean + 1) / 2; + + return ret; +} + +static bool blk_mq_poll_hybrid(struct request_queue *q, blk_qc_t qc) +{ + struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, qc); + struct request *rq = blk_qc_to_rq(hctx, qc); + struct hrtimer_sleeper hs; + enum hrtimer_mode mode; + unsigned int nsecs; + ktime_t kt; + + /* + * If a request has completed on queue that uses an I/O scheduler, we + * won't get back a request from blk_qc_to_rq. + */ + if (!rq || (rq->rq_flags & RQF_MQ_POLL_SLEPT)) + return false; + + /* + * If we get here, hybrid polling is enabled. Hence poll_nsec can be: + * + * 0: use half of prev avg + * >0: use this specific value + */ + if (q->poll_nsec > 0) + nsecs = q->poll_nsec; + else + nsecs = blk_mq_poll_nsecs(q, rq); + + if (!nsecs) + return false; + + rq->rq_flags |= RQF_MQ_POLL_SLEPT; + + /* + * This will be replaced with the stats tracking code, using + * 'avg_completion_time / 2' as the pre-sleep target. + */ + kt = nsecs; + + mode = HRTIMER_MODE_REL; + hrtimer_init_sleeper_on_stack(&hs, CLOCK_MONOTONIC, mode); + hrtimer_set_expires(&hs.timer, kt); + + do { + if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE) + break; + set_current_state(TASK_UNINTERRUPTIBLE); + hrtimer_sleeper_start_expires(&hs, mode); + if (hs.task) + io_schedule(); + hrtimer_cancel(&hs.timer); + mode = HRTIMER_MODE_ABS; + } while (hs.task && !signal_pending(current)); + + __set_current_state(TASK_RUNNING); + destroy_hrtimer_on_stack(&hs.timer); + + /* + * If we sleep, have the caller restart the poll loop to reset the + * state. Like for the other success return cases, the caller is + * responsible for checking if the IO completed. If the IO isn't + * complete, we'll get called again and will go straight to the busy + * poll loop. + */ + return true; +} + +static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t cookie, + struct io_comp_batch *iob, unsigned int flags) +{ + struct blk_mq_hw_ctx *hctx = blk_qc_to_hctx(q, cookie); + long state = get_current_state(); + int ret; + + do { + ret = q->mq_ops->poll(hctx, iob); + if (ret > 0) { + __set_current_state(TASK_RUNNING); + return ret; + } + + if (signal_pending_state(state, current)) + __set_current_state(TASK_RUNNING); + if (task_is_running(current)) + return 1; + + if (ret < 0 || (flags & BLK_POLL_ONESHOT)) + break; + cpu_relax(); + } while (!need_resched()); + + __set_current_state(TASK_RUNNING); + return 0; +} + +int blk_mq_poll(struct request_queue *q, blk_qc_t cookie, struct io_comp_batch *iob, + unsigned int flags) +{ + if (!(flags & BLK_POLL_NOSLEEP) && + q->poll_nsec != BLK_MQ_POLL_CLASSIC) { + if (blk_mq_poll_hybrid(q, cookie)) + return 1; + } + return blk_mq_poll_classic(q, cookie, iob, flags); +} + +unsigned int blk_mq_rq_cpu(struct request *rq) +{ + return rq->mq_ctx->cpu; +} +EXPORT_SYMBOL(blk_mq_rq_cpu); + +void blk_mq_cancel_work_sync(struct request_queue *q) +{ + if (queue_is_mq(q)) { + struct blk_mq_hw_ctx *hctx; + unsigned long i; + + cancel_delayed_work_sync(&q->requeue_work); + + queue_for_each_hw_ctx(q, hctx, i) + cancel_delayed_work_sync(&hctx->run_work); + } +} + +static int __init blk_mq_init(void) +{ + int i; + + for_each_possible_cpu(i) + init_llist_head(&per_cpu(blk_cpu_done, i)); + open_softirq(BLOCK_SOFTIRQ, blk_done_softirq); + + cpuhp_setup_state_nocalls(CPUHP_BLOCK_SOFTIRQ_DEAD, + "block/softirq:dead", NULL, + blk_softirq_cpu_dead); + cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, + blk_mq_hctx_notify_dead); + cpuhp_setup_state_multi(CPUHP_AP_BLK_MQ_ONLINE, "block/mq:online", + blk_mq_hctx_notify_online, + blk_mq_hctx_notify_offline); + return 0; +} +subsys_initcall(blk_mq_init); |