| /* |
| * Block multiqueue core code |
| * |
| * Copyright (C) 2013-2014 Jens Axboe |
| * Copyright (C) 2013-2014 Christoph Hellwig |
| */ |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/backing-dev.h> |
| #include <linux/bio.h> |
| #include <linux/blkdev.h> |
| #include <linux/kmemleak.h> |
| #include <linux/mm.h> |
| #include <linux/init.h> |
| #include <linux/slab.h> |
| #include <linux/workqueue.h> |
| #include <linux/smp.h> |
| #include <linux/llist.h> |
| #include <linux/list_sort.h> |
| #include <linux/cpu.h> |
| #include <linux/cache.h> |
| #include <linux/sched/sysctl.h> |
| #include <linux/sched/topology.h> |
| #include <linux/sched/signal.h> |
| #include <linux/delay.h> |
| #include <linux/crash_dump.h> |
| #include <linux/prefetch.h> |
| |
| #include <trace/events/block.h> |
| |
| #include <linux/blk-mq.h> |
| #include "blk.h" |
| #include "blk-mq.h" |
| #include "blk-mq-debugfs.h" |
| #include "blk-mq-tag.h" |
| #include "blk-stat.h" |
| #include "blk-wbt.h" |
| #include "blk-mq-sched.h" |
| |
| static void blk_mq_poll_stats_start(struct request_queue *q); |
| static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb); |
| |
| static int blk_mq_poll_stats_bkt(const struct request *rq) |
| { |
| int ddir, bytes, bucket; |
| |
| ddir = rq_data_dir(rq); |
| bytes = blk_rq_bytes(rq); |
| |
| bucket = ddir + 2*(ilog2(bytes) - 9); |
| |
| if (bucket < 0) |
| return -1; |
| else if (bucket >= BLK_MQ_POLL_STATS_BKTS) |
| return ddir + BLK_MQ_POLL_STATS_BKTS - 2; |
| |
| return bucket; |
| } |
| |
| /* |
| * Check if any of the ctx's have pending work in this hardware queue |
| */ |
| bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) |
| { |
| return sbitmap_any_bit_set(&hctx->ctx_map) || |
| !list_empty_careful(&hctx->dispatch) || |
| 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) |
| { |
| if (!sbitmap_test_bit(&hctx->ctx_map, ctx->index_hw)) |
| sbitmap_set_bit(&hctx->ctx_map, ctx->index_hw); |
| } |
| |
| static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, |
| struct blk_mq_ctx *ctx) |
| { |
| sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw); |
| } |
| |
| struct mq_inflight { |
| struct hd_struct *part; |
| unsigned int *inflight; |
| }; |
| |
| static void blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, void *priv, |
| bool reserved) |
| { |
| struct mq_inflight *mi = priv; |
| |
| if (test_bit(REQ_ATOM_STARTED, &rq->atomic_flags) && |
| !test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) { |
| /* |
| * index[0] counts the specific partition that was asked |
| * for. index[1] counts the ones that are active on the |
| * whole device, so increment that if mi->part is indeed |
| * a partition, and not a whole device. |
| */ |
| if (rq->part == mi->part) |
| mi->inflight[0]++; |
| if (mi->part->partno) |
| mi->inflight[1]++; |
| } |
| } |
| |
| void blk_mq_in_flight(struct request_queue *q, struct hd_struct *part, |
| unsigned int inflight[2]) |
| { |
| struct mq_inflight mi = { .part = part, .inflight = inflight, }; |
| |
| inflight[0] = inflight[1] = 0; |
| blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi); |
| } |
| |
| static void blk_mq_check_inflight_rw(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, void *priv, |
| bool reserved) |
| { |
| struct mq_inflight *mi = priv; |
| |
| if (rq->part == mi->part) |
| mi->inflight[rq_data_dir(rq)]++; |
| } |
| |
| void blk_mq_in_flight_rw(struct request_queue *q, struct hd_struct *part, |
| unsigned int inflight[2]) |
| { |
| struct mq_inflight mi = { .part = part, .inflight = inflight, }; |
| |
| inflight[0] = inflight[1] = 0; |
| blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight_rw, &mi); |
| } |
| |
| void blk_freeze_queue_start(struct request_queue *q) |
| { |
| int freeze_depth; |
| |
| freeze_depth = atomic_inc_return(&q->mq_freeze_depth); |
| if (freeze_depth == 1) { |
| percpu_ref_kill(&q->q_usage_counter); |
| blk_mq_run_hw_queues(q, false); |
| } |
| } |
| 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); |
| if (!q->mq_ops) |
| blk_drain_queue(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) |
| { |
| int freeze_depth; |
| |
| freeze_depth = atomic_dec_return(&q->mq_freeze_depth); |
| WARN_ON_ONCE(freeze_depth < 0); |
| if (!freeze_depth) { |
| percpu_ref_reinit(&q->q_usage_counter); |
| wake_up_all(&q->mq_freeze_wq); |
| } |
| } |
| 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); |
| queue_flag_set(QUEUE_FLAG_QUIESCED, q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); |
| |
| /** |
| * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished |
| * @q: request queue. |
| * |
| * Note: this function does not prevent that the struct request end_io() |
| * callback function is invoked. Once this function is returned, we make |
| * sure no dispatch can happen until the queue is unquiesced via |
| * blk_mq_unquiesce_queue(). |
| */ |
| void blk_mq_quiesce_queue(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| bool rcu = false; |
| |
| blk_mq_quiesce_queue_nowait(q); |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (hctx->flags & BLK_MQ_F_BLOCKING) |
| synchronize_srcu(hctx->queue_rq_srcu); |
| else |
| rcu = true; |
| } |
| if (rcu) |
| synchronize_rcu(); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); |
| |
| /* |
| * blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue() |
| * @q: request queue. |
| * |
| * This function recovers queue into the state before quiescing |
| * which is done by blk_mq_quiesce_queue. |
| */ |
| void blk_mq_unquiesce_queue(struct request_queue *q) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(q->queue_lock, flags); |
| queue_flag_clear(QUEUE_FLAG_QUIESCED, q); |
| spin_unlock_irqrestore(q->queue_lock, flags); |
| |
| /* dispatch requests which are inserted during quiescing */ |
| blk_mq_run_hw_queues(q, true); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); |
| |
| void blk_mq_wake_waiters(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| if (blk_mq_hw_queue_mapped(hctx)) |
| blk_mq_tag_wakeup_all(hctx->tags, true); |
| |
| /* |
| * If we are called because the queue has now been marked as |
| * dying, we need to ensure that processes currently waiting on |
| * the queue are notified as well. |
| */ |
| wake_up_all(&q->mq_freeze_wq); |
| } |
| |
| bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx) |
| { |
| return blk_mq_has_free_tags(hctx->tags); |
| } |
| EXPORT_SYMBOL(blk_mq_can_queue); |
| |
| static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, |
| unsigned int tag, unsigned int op) |
| { |
| struct blk_mq_tags *tags = blk_mq_tags_from_data(data); |
| struct request *rq = tags->static_rqs[tag]; |
| |
| rq->rq_flags = 0; |
| |
| if (data->flags & BLK_MQ_REQ_INTERNAL) { |
| rq->tag = -1; |
| rq->internal_tag = tag; |
| } else { |
| if (blk_mq_tag_busy(data->hctx)) { |
| rq->rq_flags = RQF_MQ_INFLIGHT; |
| atomic_inc(&data->hctx->nr_active); |
| } |
| rq->tag = tag; |
| rq->internal_tag = -1; |
| data->hctx->tags->rqs[rq->tag] = rq; |
| } |
| |
| INIT_LIST_HEAD(&rq->queuelist); |
| /* csd/requeue_work/fifo_time is initialized before use */ |
| rq->q = data->q; |
| rq->mq_ctx = data->ctx; |
| rq->cmd_flags = op; |
| if (blk_queue_io_stat(data->q)) |
| rq->rq_flags |= RQF_IO_STAT; |
| /* do not touch atomic flags, it needs atomic ops against the timer */ |
| rq->cpu = -1; |
| INIT_HLIST_NODE(&rq->hash); |
| RB_CLEAR_NODE(&rq->rb_node); |
| rq->rq_disk = NULL; |
| rq->part = NULL; |
| rq->start_time = jiffies; |
| #ifdef CONFIG_BLK_CGROUP |
| rq->rl = NULL; |
| set_start_time_ns(rq); |
| rq->io_start_time_ns = 0; |
| #endif |
| rq->nr_phys_segments = 0; |
| #if defined(CONFIG_BLK_DEV_INTEGRITY) |
| rq->nr_integrity_segments = 0; |
| #endif |
| rq->special = NULL; |
| /* tag was already set */ |
| rq->extra_len = 0; |
| |
| INIT_LIST_HEAD(&rq->timeout_list); |
| rq->timeout = 0; |
| |
| rq->end_io = NULL; |
| rq->end_io_data = NULL; |
| rq->next_rq = NULL; |
| |
| data->ctx->rq_dispatched[op_is_sync(op)]++; |
| return rq; |
| } |
| |
| static struct request *blk_mq_get_request(struct request_queue *q, |
| struct bio *bio, unsigned int op, |
| struct blk_mq_alloc_data *data) |
| { |
| struct elevator_queue *e = q->elevator; |
| struct request *rq; |
| unsigned int tag; |
| struct blk_mq_ctx *local_ctx = NULL; |
| |
| blk_queue_enter_live(q); |
| data->q = q; |
| if (likely(!data->ctx)) |
| data->ctx = local_ctx = blk_mq_get_ctx(q); |
| if (likely(!data->hctx)) |
| data->hctx = blk_mq_map_queue(q, data->ctx->cpu); |
| if (op & REQ_NOWAIT) |
| data->flags |= BLK_MQ_REQ_NOWAIT; |
| |
| if (e) { |
| data->flags |= BLK_MQ_REQ_INTERNAL; |
| |
| /* |
| * Flush requests are special and go directly to the |
| * dispatch list. |
| */ |
| if (!op_is_flush(op) && e->type->ops.mq.limit_depth) |
| e->type->ops.mq.limit_depth(op, data); |
| } |
| |
| tag = blk_mq_get_tag(data); |
| if (tag == BLK_MQ_TAG_FAIL) { |
| if (local_ctx) { |
| blk_mq_put_ctx(local_ctx); |
| data->ctx = NULL; |
| } |
| blk_queue_exit(q); |
| return NULL; |
| } |
| |
| rq = blk_mq_rq_ctx_init(data, tag, op); |
| if (!op_is_flush(op)) { |
| rq->elv.icq = NULL; |
| if (e && e->type->ops.mq.prepare_request) { |
| if (e->type->icq_cache && rq_ioc(bio)) |
| blk_mq_sched_assign_ioc(rq, bio); |
| |
| e->type->ops.mq.prepare_request(rq, bio); |
| rq->rq_flags |= RQF_ELVPRIV; |
| } |
| } |
| data->hctx->queued++; |
| return rq; |
| } |
| |
| struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op, |
| unsigned int flags) |
| { |
| struct blk_mq_alloc_data alloc_data = { .flags = flags }; |
| struct request *rq; |
| int ret; |
| |
| ret = blk_queue_enter(q, flags & BLK_MQ_REQ_NOWAIT); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| rq = blk_mq_get_request(q, NULL, op, &alloc_data); |
| blk_queue_exit(q); |
| |
| if (!rq) |
| return ERR_PTR(-EWOULDBLOCK); |
| |
| blk_mq_put_ctx(alloc_data.ctx); |
| |
| rq->__data_len = 0; |
| rq->__sector = (sector_t) -1; |
| rq->bio = rq->biotail = NULL; |
| return rq; |
| } |
| EXPORT_SYMBOL(blk_mq_alloc_request); |
| |
| struct request *blk_mq_alloc_request_hctx(struct request_queue *q, |
| unsigned int op, unsigned int flags, unsigned int hctx_idx) |
| { |
| struct blk_mq_alloc_data alloc_data = { .flags = flags }; |
| struct request *rq; |
| unsigned int cpu; |
| int ret; |
| |
| /* |
| * If the tag allocator sleeps we could get an allocation for a |
| * different hardware context. No need to complicate the low level |
| * allocator for this for the rare use case of a command tied to |
| * a specific queue. |
| */ |
| if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT))) |
| return ERR_PTR(-EINVAL); |
| |
| if (hctx_idx >= q->nr_hw_queues) |
| return ERR_PTR(-EIO); |
| |
| ret = blk_queue_enter(q, true); |
| if (ret) |
| return ERR_PTR(ret); |
| |
| /* |
| * Check if the hardware context is actually mapped to anything. |
| * If not tell the caller that it should skip this queue. |
| */ |
| alloc_data.hctx = q->queue_hw_ctx[hctx_idx]; |
| if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) { |
| blk_queue_exit(q); |
| return ERR_PTR(-EXDEV); |
| } |
| cpu = cpumask_first(alloc_data.hctx->cpumask); |
| alloc_data.ctx = __blk_mq_get_ctx(q, cpu); |
| |
| rq = blk_mq_get_request(q, NULL, op, &alloc_data); |
| blk_queue_exit(q); |
| |
| if (!rq) |
| return ERR_PTR(-EWOULDBLOCK); |
| |
| return rq; |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx); |
| |
| void blk_mq_free_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| struct elevator_queue *e = q->elevator; |
| struct blk_mq_ctx *ctx = rq->mq_ctx; |
| struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); |
| const int sched_tag = rq->internal_tag; |
| |
| if (rq->rq_flags & RQF_ELVPRIV) { |
| if (e && e->type->ops.mq.finish_request) |
| e->type->ops.mq.finish_request(rq); |
| if (rq->elv.icq) { |
| put_io_context(rq->elv.icq->ioc); |
| rq->elv.icq = NULL; |
| } |
| } |
| |
| ctx->rq_completed[rq_is_sync(rq)]++; |
| if (rq->rq_flags & RQF_MQ_INFLIGHT) |
| atomic_dec(&hctx->nr_active); |
| |
| wbt_done(q->rq_wb, &rq->issue_stat); |
| |
| clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| clear_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags); |
| if (rq->tag != -1) |
| blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag); |
| if (sched_tag != -1) |
| blk_mq_put_tag(hctx, hctx->sched_tags, ctx, sched_tag); |
| blk_mq_sched_restart(hctx); |
| blk_queue_exit(q); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_free_request); |
| |
| inline void __blk_mq_end_request(struct request *rq, blk_status_t error) |
| { |
| blk_account_io_done(rq); |
| |
| if (rq->end_io) { |
| wbt_done(rq->q->rq_wb, &rq->issue_stat); |
| rq->end_io(rq, error); |
| } else { |
| if (unlikely(blk_bidi_rq(rq))) |
| blk_mq_free_request(rq->next_rq); |
| blk_mq_free_request(rq); |
| } |
| } |
| EXPORT_SYMBOL(__blk_mq_end_request); |
| |
| void blk_mq_end_request(struct request *rq, blk_status_t error) |
| { |
| if (blk_update_request(rq, error, blk_rq_bytes(rq))) |
| BUG(); |
| __blk_mq_end_request(rq, error); |
| } |
| EXPORT_SYMBOL(blk_mq_end_request); |
| |
| static void __blk_mq_complete_request_remote(void *data) |
| { |
| struct request *rq = data; |
| |
| rq->q->softirq_done_fn(rq); |
| } |
| |
| static void __blk_mq_complete_request(struct request *rq) |
| { |
| struct blk_mq_ctx *ctx = rq->mq_ctx; |
| bool shared = false; |
| int cpu; |
| |
| if (rq->internal_tag != -1) |
| blk_mq_sched_completed_request(rq); |
| if (rq->rq_flags & RQF_STATS) { |
| blk_mq_poll_stats_start(rq->q); |
| blk_stat_add(rq); |
| } |
| |
| if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) { |
| rq->q->softirq_done_fn(rq); |
| return; |
| } |
| |
| cpu = get_cpu(); |
| if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags)) |
| shared = cpus_share_cache(cpu, ctx->cpu); |
| |
| if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) { |
| rq->csd.func = __blk_mq_complete_request_remote; |
| rq->csd.info = rq; |
| rq->csd.flags = 0; |
| smp_call_function_single_async(ctx->cpu, &rq->csd); |
| } else { |
| rq->q->softirq_done_fn(rq); |
| } |
| put_cpu(); |
| } |
| |
| /** |
| * blk_mq_complete_request - end I/O on a request |
| * @rq: the request being processed |
| * |
| * Description: |
| * Ends all I/O on a request. It does not handle partial completions. |
| * The actual completion happens out-of-order, through a IPI handler. |
| **/ |
| void blk_mq_complete_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| if (unlikely(blk_should_fake_timeout(q))) |
| return; |
| if (!blk_mark_rq_complete(rq)) |
| __blk_mq_complete_request(rq); |
| } |
| EXPORT_SYMBOL(blk_mq_complete_request); |
| |
| int blk_mq_request_started(struct request *rq) |
| { |
| return test_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_request_started); |
| |
| void blk_mq_start_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| blk_mq_sched_started_request(rq); |
| |
| trace_block_rq_issue(q, rq); |
| |
| if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) { |
| blk_stat_set_issue(&rq->issue_stat, blk_rq_sectors(rq)); |
| rq->rq_flags |= RQF_STATS; |
| wbt_issue(q->rq_wb, &rq->issue_stat); |
| } |
| |
| blk_add_timer(rq); |
| |
| /* |
| * Ensure that ->deadline is visible before set the started |
| * flag and clear the completed flag. |
| */ |
| smp_mb__before_atomic(); |
| |
| /* |
| * Mark us as started and clear complete. Complete might have been |
| * set if requeue raced with timeout, which then marked it as |
| * complete. So be sure to clear complete again when we start |
| * the request, otherwise we'll ignore the completion event. |
| */ |
| if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) |
| set_bit(REQ_ATOM_STARTED, &rq->atomic_flags); |
| if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) |
| clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags); |
| |
| if (q->dma_drain_size && blk_rq_bytes(rq)) { |
| /* |
| * Make sure space for the drain appears. We know we can do |
| * this because max_hw_segments has been adjusted to be one |
| * fewer than the device can handle. |
| */ |
| rq->nr_phys_segments++; |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_start_request); |
| |
| /* |
| * When we reach here because queue is busy, REQ_ATOM_COMPLETE |
| * flag isn't set yet, so there may be race with timeout handler, |
| * but given rq->deadline is just set in .queue_rq() under |
| * this situation, the race won't be possible in reality because |
| * rq->timeout should be set as big enough to cover the window |
| * between blk_mq_start_request() called from .queue_rq() and |
| * clearing REQ_ATOM_STARTED here. |
| */ |
| static void __blk_mq_requeue_request(struct request *rq) |
| { |
| struct request_queue *q = rq->q; |
| |
| trace_block_rq_requeue(q, rq); |
| wbt_requeue(q->rq_wb, &rq->issue_stat); |
| |
| if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) { |
| if (q->dma_drain_size && blk_rq_bytes(rq)) |
| rq->nr_phys_segments--; |
| } |
| } |
| |
| void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list) |
| { |
| __blk_mq_requeue_request(rq); |
| |
| /* this request will be re-inserted to io scheduler queue */ |
| blk_mq_sched_requeue_request(rq); |
| |
| BUG_ON(blk_queued_rq(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)) |
| continue; |
| |
| rq->rq_flags &= ~RQF_SOFTBARRIER; |
| list_del_init(&rq->queuelist); |
| blk_mq_sched_insert_request(rq, true, false, false, true); |
| } |
| |
| 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, true); |
| } |
| |
| 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 insertation 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); |
| } |
| EXPORT_SYMBOL(blk_mq_add_to_requeue_list); |
| |
| void blk_mq_kick_requeue_list(struct request_queue *q) |
| { |
| kblockd_schedule_delayed_work(&q->requeue_work, 0); |
| } |
| EXPORT_SYMBOL(blk_mq_kick_requeue_list); |
| |
| void blk_mq_delay_kick_requeue_list(struct request_queue *q, |
| unsigned long msecs) |
| { |
| kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, |
| msecs_to_jiffies(msecs)); |
| } |
| EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list); |
| |
| struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) |
| { |
| if (tag < tags->nr_tags) { |
| prefetch(tags->rqs[tag]); |
| return tags->rqs[tag]; |
| } |
| |
| return NULL; |
| } |
| EXPORT_SYMBOL(blk_mq_tag_to_rq); |
| |
| struct blk_mq_timeout_data { |
| unsigned long next; |
| unsigned int next_set; |
| }; |
| |
| void blk_mq_rq_timed_out(struct request *req, bool reserved) |
| { |
| const struct blk_mq_ops *ops = req->q->mq_ops; |
| enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER; |
| |
| /* |
| * We know that complete is set at this point. If STARTED isn't set |
| * anymore, then the request isn't active and the "timeout" should |
| * just be ignored. This can happen due to the bitflag ordering. |
| * Timeout first checks if STARTED is set, and if it is, assumes |
| * the request is active. But if we race with completion, then |
| * both flags will get cleared. So check here again, and ignore |
| * a timeout event with a request that isn't active. |
| */ |
| if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags)) |
| return; |
| |
| if (ops->timeout) |
| ret = ops->timeout(req, reserved); |
| |
| switch (ret) { |
| case BLK_EH_HANDLED: |
| __blk_mq_complete_request(req); |
| break; |
| case BLK_EH_RESET_TIMER: |
| blk_add_timer(req); |
| blk_clear_rq_complete(req); |
| break; |
| case BLK_EH_NOT_HANDLED: |
| break; |
| default: |
| printk(KERN_ERR "block: bad eh return: %d\n", ret); |
| break; |
| } |
| } |
| |
| static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, void *priv, bool reserved) |
| { |
| struct blk_mq_timeout_data *data = priv; |
| |
| if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) |
| return; |
| |
| /* |
| * The rq being checked may have been freed and reallocated |
| * out already here, we avoid this race by checking rq->deadline |
| * and REQ_ATOM_COMPLETE flag together: |
| * |
| * - if rq->deadline is observed as new value because of |
| * reusing, the rq won't be timed out because of timing. |
| * - if rq->deadline is observed as previous value, |
| * REQ_ATOM_COMPLETE flag won't be cleared in reuse path |
| * because we put a barrier between setting rq->deadline |
| * and clearing the flag in blk_mq_start_request(), so |
| * this rq won't be timed out too. |
| */ |
| if (time_after_eq(jiffies, rq->deadline)) { |
| if (!blk_mark_rq_complete(rq)) |
| blk_mq_rq_timed_out(rq, reserved); |
| } else if (!data->next_set || time_after(data->next, rq->deadline)) { |
| data->next = rq->deadline; |
| data->next_set = 1; |
| } |
| } |
| |
| static void blk_mq_timeout_work(struct work_struct *work) |
| { |
| struct request_queue *q = |
| container_of(work, struct request_queue, timeout_work); |
| struct blk_mq_timeout_data data = { |
| .next = 0, |
| .next_set = 0, |
| }; |
| int i; |
| |
| /* A deadlock might occur if a request is stuck requiring a |
| * timeout at the same time a queue freeze is waiting |
| * completion, since the timeout code would not be able to |
| * acquire the queue reference here. |
| * |
| * That's why we don't use blk_queue_enter here; instead, we use |
| * percpu_ref_tryget directly, because we need to be able to |
| * obtain a reference even in the short window between the queue |
| * starting to freeze, by dropping the first reference in |
| * blk_freeze_queue_start, and the moment the last request is |
| * consumed, marked by the instant q_usage_counter reaches |
| * zero. |
| */ |
| if (!percpu_ref_tryget(&q->q_usage_counter)) |
| return; |
| |
| blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data); |
| |
| if (data.next_set) { |
| data.next = blk_rq_timeout(round_jiffies_up(data.next)); |
| mod_timer(&q->timeout, data.next); |
| } else { |
| struct blk_mq_hw_ctx *hctx; |
| |
| 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]; |
| |
| sbitmap_clear_bit(sb, bitnr); |
| spin_lock(&ctx->lock); |
| list_splice_tail_init(&ctx->rq_list, flush_data->list); |
| 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); |
| |
| static inline unsigned int queued_to_index(unsigned int queued) |
| { |
| if (!queued) |
| return 0; |
| |
| return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1); |
| } |
| |
| bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx, |
| bool wait) |
| { |
| struct blk_mq_alloc_data data = { |
| .q = rq->q, |
| .hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu), |
| .flags = wait ? 0 : BLK_MQ_REQ_NOWAIT, |
| }; |
| |
| might_sleep_if(wait); |
| |
| if (rq->tag != -1) |
| goto done; |
| |
| if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag)) |
| data.flags |= BLK_MQ_REQ_RESERVED; |
| |
| rq->tag = blk_mq_get_tag(&data); |
| if (rq->tag >= 0) { |
| if (blk_mq_tag_busy(data.hctx)) { |
| rq->rq_flags |= RQF_MQ_INFLIGHT; |
| atomic_inc(&data.hctx->nr_active); |
| } |
| data.hctx->tags->rqs[rq->tag] = rq; |
| } |
| |
| done: |
| if (hctx) |
| *hctx = data.hctx; |
| return rq->tag != -1; |
| } |
| |
| static void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx, |
| struct request *rq) |
| { |
| blk_mq_put_tag(hctx, hctx->tags, rq->mq_ctx, rq->tag); |
| rq->tag = -1; |
| |
| if (rq->rq_flags & RQF_MQ_INFLIGHT) { |
| rq->rq_flags &= ~RQF_MQ_INFLIGHT; |
| atomic_dec(&hctx->nr_active); |
| } |
| } |
| |
| static void blk_mq_put_driver_tag_hctx(struct blk_mq_hw_ctx *hctx, |
| struct request *rq) |
| { |
| if (rq->tag == -1 || rq->internal_tag == -1) |
| return; |
| |
| __blk_mq_put_driver_tag(hctx, rq); |
| } |
| |
| static void blk_mq_put_driver_tag(struct request *rq) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| |
| if (rq->tag == -1 || rq->internal_tag == -1) |
| return; |
| |
| hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu); |
| __blk_mq_put_driver_tag(hctx, rq); |
| } |
| |
| /* |
| * If we fail getting a driver tag because all the driver tags are already |
| * assigned and on the dispatch list, BUT the first entry does not have a |
| * tag, then we could deadlock. For that case, move entries with assigned |
| * driver tags to the front, leaving the set of tagged requests in the |
| * same order, and the untagged set in the same order. |
| */ |
| static bool reorder_tags_to_front(struct list_head *list) |
| { |
| struct request *rq, *tmp, *first = NULL; |
| |
| list_for_each_entry_safe_reverse(rq, tmp, list, queuelist) { |
| if (rq == first) |
| break; |
| if (rq->tag != -1) { |
| list_move(&rq->queuelist, list); |
| if (!first) |
| first = rq; |
| } |
| } |
| |
| return first != NULL; |
| } |
| |
| 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); |
| |
| list_del(&wait->entry); |
| clear_bit_unlock(BLK_MQ_S_TAG_WAITING, &hctx->state); |
| blk_mq_run_hw_queue(hctx, true); |
| return 1; |
| } |
| |
| static bool blk_mq_dispatch_wait_add(struct blk_mq_hw_ctx *hctx) |
| { |
| struct sbq_wait_state *ws; |
| |
| /* |
| * The TAG_WAITING bit serves as a lock protecting hctx->dispatch_wait. |
| * The thread which wins the race to grab this bit adds the hardware |
| * queue to the wait queue. |
| */ |
| if (test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state) || |
| test_and_set_bit_lock(BLK_MQ_S_TAG_WAITING, &hctx->state)) |
| return false; |
| |
| init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake); |
| ws = bt_wait_ptr(&hctx->tags->bitmap_tags, hctx); |
| |
| /* |
| * As soon as this returns, it's no longer safe to fiddle with |
| * hctx->dispatch_wait, since a completion can wake up the wait queue |
| * and unlock the bit. |
| */ |
| add_wait_queue(&ws->wait, &hctx->dispatch_wait); |
| return true; |
| } |
| |
| bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| struct request *rq; |
| int errors, queued; |
| |
| 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; |
| blk_status_t ret; |
| |
| rq = list_first_entry(list, struct request, queuelist); |
| if (!blk_mq_get_driver_tag(rq, &hctx, false)) { |
| if (!queued && reorder_tags_to_front(list)) |
| continue; |
| |
| /* |
| * The initial allocation attempt failed, so we need to |
| * rerun the hardware queue when a tag is freed. |
| */ |
| if (!blk_mq_dispatch_wait_add(hctx)) |
| break; |
| |
| /* |
| * It's possible that a tag was freed in the window |
| * between the allocation failure and adding the |
| * hardware queue to the wait queue. |
| */ |
| if (!blk_mq_get_driver_tag(rq, &hctx, false)) |
| 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 { |
| struct request *nxt; |
| |
| nxt = list_first_entry(list, struct request, queuelist); |
| bd.last = !blk_mq_get_driver_tag(nxt, NULL, false); |
| } |
| |
| ret = q->mq_ops->queue_rq(hctx, &bd); |
| if (ret == BLK_STS_RESOURCE) { |
| blk_mq_put_driver_tag_hctx(hctx, rq); |
| list_add(&rq->queuelist, list); |
| __blk_mq_requeue_request(rq); |
| break; |
| } |
| |
| if (unlikely(ret != BLK_STS_OK)) { |
| errors++; |
| blk_mq_end_request(rq, BLK_STS_IOERR); |
| continue; |
| } |
| |
| queued++; |
| } while (!list_empty(list)); |
| |
| hctx->dispatched[queued_to_index(queued)]++; |
| |
| /* |
| * Any items that need requeuing? Stuff them into hctx->dispatch, |
| * that is where we will continue on next queue run. |
| */ |
| if (!list_empty(list)) { |
| /* |
| * If an I/O scheduler has been configured and we got a driver |
| * tag for the next request already, free it again. |
| */ |
| rq = list_first_entry(list, struct request, queuelist); |
| blk_mq_put_driver_tag(rq); |
| |
| spin_lock(&hctx->lock); |
| list_splice_init(list, &hctx->dispatch); |
| spin_unlock(&hctx->lock); |
| |
| /* |
| * If SCHED_RESTART was set by the caller of this function and |
| * it is no longer set that means that it was cleared by another |
| * thread and hence that a queue rerun is needed. |
| * |
| * If TAG_WAITING is set that means that an I/O scheduler has |
| * been configured and another thread is waiting for a driver |
| * tag. To guarantee fairness, do not rerun this hardware queue |
| * but let the other thread grab the driver tag. |
| * |
| * 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 (!blk_mq_sched_needs_restart(hctx) && |
| !test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state)) |
| blk_mq_run_hw_queue(hctx, true); |
| } |
| |
| return (queued + errors) != 0; |
| } |
| |
| static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx) |
| { |
| int srcu_idx; |
| |
| /* |
| * We should be running this queue from one of the CPUs that |
| * are mapped to it. |
| * |
| * There are at least two related races now between setting |
| * hctx->next_cpu from blk_mq_hctx_next_cpu() and running |
| * __blk_mq_run_hw_queue(): |
| * |
| * - hctx->next_cpu is found offline in blk_mq_hctx_next_cpu(), |
| * but later it becomes online, then this warning is harmless |
| * at all |
| * |
| * - hctx->next_cpu is found online in blk_mq_hctx_next_cpu(), |
| * but later it becomes offline, then the warning can't be |
| * triggered, and we depend on blk-mq timeout handler to |
| * handle dispatched requests to this hctx |
| */ |
| if (!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) && |
| cpu_online(hctx->next_cpu)) { |
| printk(KERN_WARNING "run queue from wrong CPU %d, hctx %s\n", |
| raw_smp_processor_id(), |
| cpumask_empty(hctx->cpumask) ? "inactive": "active"); |
| dump_stack(); |
| } |
| |
| /* |
| * We can't run the queue inline with ints disabled. Ensure that |
| * we catch bad users of this early. |
| */ |
| WARN_ON_ONCE(in_interrupt()); |
| |
| if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { |
| rcu_read_lock(); |
| blk_mq_sched_dispatch_requests(hctx); |
| rcu_read_unlock(); |
| } else { |
| might_sleep(); |
| |
| srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); |
| blk_mq_sched_dispatch_requests(hctx); |
| srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); |
| } |
| } |
| |
| /* |
| * 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) |
| { |
| if (hctx->queue->nr_hw_queues == 1) |
| return WORK_CPU_UNBOUND; |
| |
| if (--hctx->next_cpu_batch <= 0) { |
| int next_cpu; |
| |
| next_cpu = cpumask_next(hctx->next_cpu, hctx->cpumask); |
| if (next_cpu >= nr_cpu_ids) |
| next_cpu = cpumask_first(hctx->cpumask); |
| |
| hctx->next_cpu = next_cpu; |
| hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
| } |
| |
| return hctx->next_cpu; |
| } |
| |
| static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async, |
| unsigned long msecs) |
| { |
| if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx))) |
| return; |
| |
| if (unlikely(blk_mq_hctx_stopped(hctx))) |
| return; |
| |
| if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) { |
| int cpu = get_cpu(); |
| if (cpumask_test_cpu(cpu, hctx->cpumask)) { |
| __blk_mq_run_hw_queue(hctx); |
| put_cpu(); |
| return; |
| } |
| |
| put_cpu(); |
| } |
| |
| kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx), |
| &hctx->run_work, |
| msecs_to_jiffies(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); |
| |
| void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) |
| { |
| __blk_mq_delay_run_hw_queue(hctx, async, 0); |
| } |
| EXPORT_SYMBOL(blk_mq_run_hw_queue); |
| |
| void blk_mq_run_hw_queues(struct request_queue *q, bool async) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (!blk_mq_hctx_has_pending(hctx) || |
| blk_mq_hctx_stopped(hctx)) |
| continue; |
| |
| blk_mq_run_hw_queue(hctx, async); |
| } |
| } |
| EXPORT_SYMBOL(blk_mq_run_hw_queues); |
| |
| /** |
| * blk_mq_queue_stopped() - check whether one or more hctxs have been stopped |
| * @q: request queue. |
| * |
| * The caller is responsible for serializing this function against |
| * blk_mq_{start,stop}_hw_queue(). |
| */ |
| bool blk_mq_queue_stopped(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| if (blk_mq_hctx_stopped(hctx)) |
| return true; |
| |
| return false; |
| } |
| EXPORT_SYMBOL(blk_mq_queue_stopped); |
| |
| /* |
| * This function is often used for pausing .queue_rq() by driver when |
| * there isn't enough resource or some conditions aren't satisfied, and |
| * BLK_STS_RESOURCE is usually returned. |
| * |
| * We do not guarantee that dispatch can be drained or blocked |
| * after blk_mq_stop_hw_queue() returns. Please use |
| * blk_mq_quiesce_queue() for that requirement. |
| */ |
| void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) |
| { |
| cancel_delayed_work(&hctx->run_work); |
| |
| set_bit(BLK_MQ_S_STOPPED, &hctx->state); |
| } |
| EXPORT_SYMBOL(blk_mq_stop_hw_queue); |
| |
| /* |
| * This function is often used for pausing .queue_rq() by driver when |
| * there isn't enough resource or some conditions aren't satisfied, and |
| * BLK_STS_RESOURCE is usually returned. |
| * |
| * We do not guarantee that dispatch can be drained or blocked |
| * after blk_mq_stop_hw_queues() returns. Please use |
| * blk_mq_quiesce_queue() for that requirement. |
| */ |
| void blk_mq_stop_hw_queues(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| blk_mq_stop_hw_queue(hctx); |
| } |
| EXPORT_SYMBOL(blk_mq_stop_hw_queues); |
| |
| void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) |
| { |
| clear_bit(BLK_MQ_S_STOPPED, &hctx->state); |
| |
| blk_mq_run_hw_queue(hctx, false); |
| } |
| EXPORT_SYMBOL(blk_mq_start_hw_queue); |
| |
| void blk_mq_start_hw_queues(struct request_queue *q) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| blk_mq_start_hw_queue(hctx); |
| } |
| EXPORT_SYMBOL(blk_mq_start_hw_queues); |
| |
| void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) |
| { |
| if (!blk_mq_hctx_stopped(hctx)) |
| return; |
| |
| clear_bit(BLK_MQ_S_STOPPED, &hctx->state); |
| blk_mq_run_hw_queue(hctx, async); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue); |
| |
| void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) |
| blk_mq_start_stopped_hw_queue(hctx, async); |
| } |
| EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); |
| |
| static void blk_mq_run_work_fn(struct work_struct *work) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| |
| hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); |
| |
| /* |
| * If we are stopped, don't run the queue. The exception is if |
| * BLK_MQ_S_START_ON_RUN is set. For that case, we auto-clear |
| * the STOPPED bit and run it. |
| */ |
| if (test_bit(BLK_MQ_S_STOPPED, &hctx->state)) { |
| if (!test_bit(BLK_MQ_S_START_ON_RUN, &hctx->state)) |
| return; |
| |
| clear_bit(BLK_MQ_S_START_ON_RUN, &hctx->state); |
| clear_bit(BLK_MQ_S_STOPPED, &hctx->state); |
| } |
| |
| __blk_mq_run_hw_queue(hctx); |
| } |
| |
| |
| void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs) |
| { |
| if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx))) |
| return; |
| |
| /* |
| * Stop the hw queue, then modify currently delayed work. |
| * This should prevent us from running the queue prematurely. |
| * Mark the queue as auto-clearing STOPPED when it runs. |
| */ |
| blk_mq_stop_hw_queue(hctx); |
| set_bit(BLK_MQ_S_START_ON_RUN, &hctx->state); |
| kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), |
| &hctx->run_work, |
| msecs_to_jiffies(msecs)); |
| } |
| EXPORT_SYMBOL(blk_mq_delay_queue); |
| |
| 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; |
| |
| lockdep_assert_held(&ctx->lock); |
| |
| trace_block_rq_insert(hctx->queue, rq); |
| |
| if (at_head) |
| list_add(&rq->queuelist, &ctx->rq_list); |
| else |
| list_add_tail(&rq->queuelist, &ctx->rq_list); |
| } |
| |
| 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); |
| } |
| |
| /* |
| * 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) |
| { |
| struct blk_mq_ctx *ctx = rq->mq_ctx; |
| struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(rq->q, ctx->cpu); |
| |
| spin_lock(&hctx->lock); |
| list_add_tail(&rq->queuelist, &hctx->dispatch); |
| spin_unlock(&hctx->lock); |
| |
| 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) |
| |
| { |
| /* |
| * preemption doesn't flush plug list, so it's possible ctx->cpu is |
| * offline now |
| */ |
| spin_lock(&ctx->lock); |
| while (!list_empty(list)) { |
| struct request *rq; |
| |
| rq = list_first_entry(list, struct request, queuelist); |
| BUG_ON(rq->mq_ctx != ctx); |
| list_del_init(&rq->queuelist); |
| __blk_mq_insert_req_list(hctx, rq, false); |
| } |
| blk_mq_hctx_mark_pending(hctx, ctx); |
| spin_unlock(&ctx->lock); |
| } |
| |
| static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b) |
| { |
| struct request *rqa = container_of(a, struct request, queuelist); |
| struct request *rqb = container_of(b, struct request, queuelist); |
| |
| return !(rqa->mq_ctx < rqb->mq_ctx || |
| (rqa->mq_ctx == rqb->mq_ctx && |
| blk_rq_pos(rqa) < blk_rq_pos(rqb))); |
| } |
| |
| void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
| { |
| struct blk_mq_ctx *this_ctx; |
| struct request_queue *this_q; |
| struct request *rq; |
| LIST_HEAD(list); |
| LIST_HEAD(ctx_list); |
| unsigned int depth; |
| |
| list_splice_init(&plug->mq_list, &list); |
| |
| list_sort(NULL, &list, plug_ctx_cmp); |
| |
| this_q = NULL; |
| this_ctx = NULL; |
| depth = 0; |
| |
| while (!list_empty(&list)) { |
| rq = list_entry_rq(list.next); |
| list_del_init(&rq->queuelist); |
| BUG_ON(!rq->q); |
| if (rq->mq_ctx != this_ctx) { |
| if (this_ctx) { |
| trace_block_unplug(this_q, depth, !from_schedule); |
| blk_mq_sched_insert_requests(this_q, this_ctx, |
| &ctx_list, |
| from_schedule); |
| } |
| |
| this_ctx = rq->mq_ctx; |
| this_q = rq->q; |
| depth = 0; |
| } |
| |
| depth++; |
| list_add_tail(&rq->queuelist, &ctx_list); |
| } |
| |
| /* |
| * If 'this_ctx' is set, we know we have entries to complete |
| * on 'ctx_list'. Do those. |
| */ |
| if (this_ctx) { |
| trace_block_unplug(this_q, depth, !from_schedule); |
| blk_mq_sched_insert_requests(this_q, this_ctx, &ctx_list, |
| from_schedule); |
| } |
| } |
| |
| static void blk_mq_bio_to_request(struct request *rq, struct bio *bio) |
| { |
| blk_init_request_from_bio(rq, bio); |
| |
| blk_account_io_start(rq, true); |
| } |
| |
| static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx) |
| { |
| return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) && |
| !blk_queue_nomerges(hctx->queue); |
| } |
| |
| static inline void blk_mq_queue_io(struct blk_mq_hw_ctx *hctx, |
| struct blk_mq_ctx *ctx, |
| struct request *rq) |
| { |
| spin_lock(&ctx->lock); |
| __blk_mq_insert_request(hctx, rq, false); |
| spin_unlock(&ctx->lock); |
| } |
| |
| static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq) |
| { |
| if (rq->tag != -1) |
| return blk_tag_to_qc_t(rq->tag, hctx->queue_num, false); |
| |
| return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true); |
| } |
| |
| static void __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, |
| blk_qc_t *cookie, bool may_sleep) |
| { |
| struct request_queue *q = rq->q; |
| struct blk_mq_queue_data bd = { |
| .rq = rq, |
| .last = true, |
| }; |
| blk_qc_t new_cookie; |
| blk_status_t ret; |
| bool run_queue = true; |
| |
| /* RCU or SRCU read lock is needed before checking quiesced flag */ |
| if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { |
| run_queue = false; |
| goto insert; |
| } |
| |
| if (q->elevator) |
| goto insert; |
| |
| if (!blk_mq_get_driver_tag(rq, NULL, false)) |
| goto insert; |
| |
| new_cookie = request_to_qc_t(hctx, rq); |
| |
| /* |
| * For OK queue, we are done. For error, 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: |
| *cookie = new_cookie; |
| return; |
| case BLK_STS_RESOURCE: |
| __blk_mq_requeue_request(rq); |
| goto insert; |
| default: |
| *cookie = BLK_QC_T_NONE; |
| blk_mq_end_request(rq, ret); |
| return; |
| } |
| |
| insert: |
| blk_mq_sched_insert_request(rq, false, run_queue, false, may_sleep); |
| } |
| |
| static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, |
| struct request *rq, blk_qc_t *cookie) |
| { |
| if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { |
| rcu_read_lock(); |
| __blk_mq_try_issue_directly(hctx, rq, cookie, false); |
| rcu_read_unlock(); |
| } else { |
| unsigned int srcu_idx; |
| |
| might_sleep(); |
| |
| srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); |
| __blk_mq_try_issue_directly(hctx, rq, cookie, true); |
| srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); |
| } |
| } |
| |
| static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) |
| { |
| const int is_sync = op_is_sync(bio->bi_opf); |
| const int is_flush_fua = op_is_flush(bio->bi_opf); |
| struct blk_mq_alloc_data data = { .flags = 0 }; |
| struct request *rq; |
| unsigned int request_count = 0; |
| struct blk_plug *plug; |
| struct request *same_queue_rq = NULL; |
| blk_qc_t cookie; |
| unsigned int wb_acct; |
| |
| blk_queue_bounce(q, &bio); |
| |
| blk_queue_split(q, &bio); |
| |
| if (!bio_integrity_prep(bio)) |
| return BLK_QC_T_NONE; |
| |
| if (!is_flush_fua && !blk_queue_nomerges(q) && |
| blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq)) |
| return BLK_QC_T_NONE; |
| |
| if (blk_mq_sched_bio_merge(q, bio)) |
| return BLK_QC_T_NONE; |
| |
| wb_acct = wbt_wait(q->rq_wb, bio, NULL); |
| |
| trace_block_getrq(q, bio, bio->bi_opf); |
| |
| rq = blk_mq_get_request(q, bio, bio->bi_opf, &data); |
| if (unlikely(!rq)) { |
| __wbt_done(q->rq_wb, wb_acct); |
| if (bio->bi_opf & REQ_NOWAIT) |
| bio_wouldblock_error(bio); |
| return BLK_QC_T_NONE; |
| } |
| |
| wbt_track(&rq->issue_stat, wb_acct); |
| |
| cookie = request_to_qc_t(data.hctx, rq); |
| |
| plug = current->plug; |
| if (unlikely(is_flush_fua)) { |
| blk_mq_put_ctx(data.ctx); |
| blk_mq_bio_to_request(rq, bio); |
| if (q->elevator) { |
| blk_mq_sched_insert_request(rq, false, true, true, |
| true); |
| } else { |
| blk_insert_flush(rq); |
| blk_mq_run_hw_queue(data.hctx, true); |
| } |
| } else if (plug && q->nr_hw_queues == 1) { |
| struct request *last = NULL; |
| |
| blk_mq_put_ctx(data.ctx); |
| blk_mq_bio_to_request(rq, bio); |
| |
| /* |
| * @request_count may become stale because of schedule |
| * out, so check the list again. |
| */ |
| if (list_empty(&plug->mq_list)) |
| request_count = 0; |
| else if (blk_queue_nomerges(q)) |
| request_count = blk_plug_queued_count(q); |
| |
| if (!request_count) |
| trace_block_plug(q); |
| else |
| last = list_entry_rq(plug->mq_list.prev); |
| |
| if (request_count >= BLK_MAX_REQUEST_COUNT || (last && |
| blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { |
| blk_flush_plug_list(plug, false); |
| trace_block_plug(q); |
| } |
| |
| list_add_tail(&rq->queuelist, &plug->mq_list); |
| } else if (plug && !blk_queue_nomerges(q)) { |
| blk_mq_bio_to_request(rq, bio); |
| |
| /* |
| * We do limited plugging. If the bio can be merged, do that. |
| * Otherwise the existing request in the plug list will be |
| * issued. So the plug list will have one request at most |
| * The plug list might get flushed before this. If that happens, |
| * the plug list is empty, and same_queue_rq is invalid. |
| */ |
| if (list_empty(&plug->mq_list)) |
| same_queue_rq = NULL; |
| if (same_queue_rq) |
| list_del_init(&same_queue_rq->queuelist); |
| list_add_tail(&rq->queuelist, &plug->mq_list); |
| |
| blk_mq_put_ctx(data.ctx); |
| |
| if (same_queue_rq) { |
| data.hctx = blk_mq_map_queue(q, |
| same_queue_rq->mq_ctx->cpu); |
| blk_mq_try_issue_directly(data.hctx, same_queue_rq, |
| &cookie); |
| } |
| } else if (q->nr_hw_queues > 1 && is_sync) { |
| blk_mq_put_ctx(data.ctx); |
| blk_mq_bio_to_request(rq, bio); |
| blk_mq_try_issue_directly(data.hctx, rq, &cookie); |
| } else if (q->elevator) { |
| blk_mq_put_ctx(data.ctx); |
| blk_mq_bio_to_request(rq, bio); |
| blk_mq_sched_insert_request(rq, false, true, true, true); |
| } else { |
| blk_mq_put_ctx(data.ctx); |
| blk_mq_bio_to_request(rq, bio); |
| blk_mq_queue_io(data.hctx, data.ctx, rq); |
| blk_mq_run_hw_queue(data.hctx, true); |
| } |
| |
| return cookie; |
| } |
| |
| void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, |
| unsigned int hctx_idx) |
| { |
| struct page *page; |
| |
| if (tags->rqs && set->ops->exit_request) { |
| int i; |
| |
| for (i = 0; i < tags->nr_tags; i++) { |
| struct request *rq = tags->static_rqs[i]; |
| |
| if (!rq) |
| continue; |
| set->ops->exit_request(set, rq, hctx_idx); |
| tags->static_rqs[i] = NULL; |
| } |
| } |
| |
| while (!list_empty(&tags->page_list)) { |
| page = list_first_entry(&tags->page_list, struct page, lru); |
| list_del_init(&page->lru); |
| /* |
| * Remove kmemleak object previously allocated in |
| * blk_mq_init_rq_map(). |
| */ |
| kmemleak_free(page_address(page)); |
| __free_pages(page, page->private); |
| } |
| } |
| |
| void blk_mq_free_rq_map(struct blk_mq_tags *tags) |
| { |
| kfree(tags->rqs); |
| tags->rqs = NULL; |
| kfree(tags->static_rqs); |
| tags->static_rqs = NULL; |
| |
| blk_mq_free_tags(tags); |
| } |
| |
| struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, |
| unsigned int hctx_idx, |
| unsigned int nr_tags, |
| unsigned int reserved_tags) |
| { |
| struct blk_mq_tags *tags; |
| int node; |
| |
| node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx); |
| if (node == NUMA_NO_NODE) |
| node = set->numa_node; |
| |
| tags = blk_mq_init_tags(nr_tags, reserved_tags, node, |
| BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags)); |
| if (!tags) |
| return NULL; |
| |
| tags->rqs = kzalloc_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 = kzalloc_node(nr_tags * sizeof(struct request *), |
| GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY, |
| node); |
| if (!tags->static_rqs) { |
| kfree(tags->rqs); |
| blk_mq_free_tags(tags); |
| return NULL; |
| } |
| |
| return tags; |
| } |
| |
| static size_t order_to_size(unsigned int order) |
| { |
| return (size_t)PAGE_SIZE << order; |
| } |
| |
| int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, |
| unsigned int hctx_idx, unsigned int depth) |
| { |
| unsigned int i, j, entries_per_page, max_order = 4; |
| size_t rq_size, left; |
| int node; |
| |
| node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx); |
| if (node == NUMA_NO_NODE) |
| node = set->numa_node; |
| |
| INIT_LIST_HEAD(&tags->page_list); |
| |
| /* |
| * rq_size is the size of the request plus driver payload, rounded |
| * to the cacheline size |
| */ |
| rq_size = round_up(sizeof(struct request) + set->cmd_size, |
| cache_line_size()); |
| left = rq_size * depth; |
| |
| for (i = 0; i < depth; ) { |
| int this_order = max_order; |
| struct page *page; |
| int to_do; |
| void *p; |
| |
| while (this_order && left < order_to_size(this_order - 1)) |
| this_order--; |
| |
| do { |
| page = alloc_pages_node(node, |
| GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO, |
| this_order); |
| if (page) |
| break; |
| if (!this_order--) |
| break; |
| if (order_to_size(this_order) < rq_size) |
| break; |
| } while (1); |
| |
| if (!page) |
| goto fail; |
| |
| page->private = this_order; |
| list_add_tail(&page->lru, &tags->page_list); |
| |
| p = page_address(page); |
| /* |
| * Allow kmemleak to scan these pages as they contain pointers |
| * to additional allocations like via ops->init_request(). |
| */ |
| kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO); |
| entries_per_page = order_to_size(this_order) / rq_size; |
| to_do = min(entries_per_page, depth - i); |
| left -= to_do * rq_size; |
| for (j = 0; j < to_do; j++) { |
| struct request *rq = p; |
| |
| tags->static_rqs[i] = rq; |
| if (set->ops->init_request) { |
| if (set->ops->init_request(set, rq, hctx_idx, |
| node)) { |
| tags->static_rqs[i] = NULL; |
| goto fail; |
| } |
| } |
| |
| p += rq_size; |
| i++; |
| } |
| } |
| return 0; |
| |
| fail: |
| blk_mq_free_rqs(set, tags, hctx_idx); |
| return -ENOMEM; |
| } |
| |
| /* |
| * 'cpu' is going away. splice any existing rq_list entries from this |
| * software queue to the hw queue dispatch list, and ensure that it |
| * gets run. |
| */ |
| static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| struct blk_mq_ctx *ctx; |
| LIST_HEAD(tmp); |
| |
| hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead); |
| ctx = __blk_mq_get_ctx(hctx->queue, cpu); |
| |
| spin_lock(&ctx->lock); |
| if (!list_empty(&ctx->rq_list)) { |
| list_splice_init(&ctx->rq_list, &tmp); |
| blk_mq_hctx_clear_pending(hctx, ctx); |
| } |
| spin_unlock(&ctx->lock); |
| |
| if (list_empty(&tmp)) |
| return 0; |
| |
| spin_lock(&hctx->lock); |
| list_splice_tail_init(&tmp, &hctx->dispatch); |
| spin_unlock(&hctx->lock); |
| |
| blk_mq_run_hw_queue(hctx, true); |
| return 0; |
| } |
| |
| static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx) |
| { |
| cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD, |
| &hctx->cpuhp_dead); |
| } |
| |
| /* hctx->ctxs will be freed in queue's release handler */ |
| static void blk_mq_exit_hctx(struct request_queue *q, |
| struct blk_mq_tag_set *set, |
| struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx) |
| { |
| blk_mq_debugfs_unregister_hctx(hctx); |
| |
| if (blk_mq_hw_queue_mapped(hctx)) |
| blk_mq_tag_idle(hctx); |
| |
| if (set->ops->exit_request) |
| set->ops->exit_request(set, hctx->fq->flush_rq, hctx_idx); |
| |
| blk_mq_sched_exit_hctx(q, hctx, hctx_idx); |
| |
| if (set->ops->exit_hctx) |
| set->ops->exit_hctx(hctx, hctx_idx); |
| |
| if (hctx->flags & BLK_MQ_F_BLOCKING) |
| cleanup_srcu_struct(hctx->queue_rq_srcu); |
| |
| blk_mq_remove_cpuhp(hctx); |
| blk_free_flush_queue(hctx->fq); |
| sbitmap_free(&hctx->ctx_map); |
| } |
| |
| static void blk_mq_exit_hw_queues(struct request_queue *q, |
| struct blk_mq_tag_set *set, int nr_queue) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| unsigned int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (i == nr_queue) |
| break; |
| blk_mq_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) |
| { |
| int node; |
| |
| node = hctx->numa_node; |
| if (node == NUMA_NO_NODE) |
| node = hctx->numa_node = set->numa_node; |
| |
| INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); |
| spin_lock_init(&hctx->lock); |
| INIT_LIST_HEAD(&hctx->dispatch); |
| hctx->queue = q; |
| hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED; |
| |
| cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead); |
| |
| hctx->tags = set->tags[hctx_idx]; |
| |
| /* |
| * Allocate space for all possible cpus to avoid allocation at |
| * runtime |
| */ |
| hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *), |
| GFP_KERNEL, node); |
| if (!hctx->ctxs) |
| goto unregister_cpu_notifier; |
| |
| if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), GFP_KERNEL, |
| node)) |
| goto free_ctxs; |
| |
| hctx->nr_ctx = 0; |
| |
| if (set->ops->init_hctx && |
| set->ops->init_hctx(hctx, set->driver_data, hctx_idx)) |
| goto free_bitmap; |
| |
| if (blk_mq_sched_init_hctx(q, hctx, hctx_idx)) |
| goto exit_hctx; |
| |
| hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size); |
| if (!hctx->fq) |
| goto sched_exit_hctx; |
| |
| if (set->ops->init_request && |
| set->ops->init_request(set, hctx->fq->flush_rq, hctx_idx, |
| node)) |
| goto free_fq; |
| |
| if (hctx->flags & BLK_MQ_F_BLOCKING) |
| init_srcu_struct(hctx->queue_rq_srcu); |
| |
| blk_mq_debugfs_register_hctx(q, hctx); |
| |
| return 0; |
| |
| free_fq: |
| kfree(hctx->fq); |
| sched_exit_hctx: |
| blk_mq_sched_exit_hctx(q, hctx, hctx_idx); |
| exit_hctx: |
| if (set->ops->exit_hctx) |
| set->ops->exit_hctx(hctx, hctx_idx); |
| free_bitmap: |
| sbitmap_free(&hctx->ctx_map); |
| free_ctxs: |
| kfree(hctx->ctxs); |
| unregister_cpu_notifier: |
| blk_mq_remove_cpuhp(hctx); |
| return -1; |
| } |
| |
| static void blk_mq_init_cpu_queues(struct request_queue *q, |
| unsigned int nr_hw_queues) |
| { |
| unsigned int i; |
| |
| for_each_possible_cpu(i) { |
| struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); |
| struct blk_mq_hw_ctx *hctx; |
| |
| __ctx->cpu = i; |
| spin_lock_init(&__ctx->lock); |
| INIT_LIST_HEAD(&__ctx->rq_list); |
| __ctx->queue = q; |
| |
| /* If the cpu isn't present, the cpu is mapped to first hctx */ |
| if (!cpu_present(i)) |
| continue; |
| |
| hctx = blk_mq_map_queue(q, i); |
| |
| /* |
| * Set local node, IFF we have more than one hw queue. If |
| * not, we remain on the home node of the device |
| */ |
| if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) |
| hctx->numa_node = local_memory_node(cpu_to_node(i)); |
| } |
| } |
| |
| static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx) |
| { |
| int ret = 0; |
| |
| set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx, |
| set->queue_depth, set->reserved_tags); |
| if (!set->tags[hctx_idx]) |
| return false; |
| |
| ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx, |
| set->queue_depth); |
| if (!ret) |
| return true; |
| |
| blk_mq_free_rq_map(set->tags[hctx_idx]); |
| set->tags[hctx_idx] = NULL; |
| return false; |
| } |
| |
| static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set, |
| unsigned int hctx_idx) |
| { |
| if (set->tags[hctx_idx]) { |
| blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx); |
| blk_mq_free_rq_map(set->tags[hctx_idx]); |
| set->tags[hctx_idx] = NULL; |
| } |
| } |
| |
| static void blk_mq_map_swqueue(struct request_queue *q) |
| { |
| unsigned int i, hctx_idx; |
| struct blk_mq_hw_ctx *hctx; |
| struct blk_mq_ctx *ctx; |
| struct blk_mq_tag_set *set = q->tag_set; |
| |
| /* |
| * Avoid others reading imcomplete hctx->cpumask through sysfs |
| */ |
| mutex_lock(&q->sysfs_lock); |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| cpumask_clear(hctx->cpumask); |
| hctx->nr_ctx = 0; |
| } |
| |
| /* |
| * Map software to hardware queues. |
| * |
| * If the cpu isn't present, the cpu is mapped to first hctx. |
| */ |
| for_each_present_cpu(i) { |
| hctx_idx = q->mq_map[i]; |
| /* unmapped hw queue can be remapped after CPU topo changed */ |
| if (!set->tags[hctx_idx] && |
| !__blk_mq_alloc_rq_map(set, hctx_idx)) { |
| /* |
| * If tags initialization fail for some hctx, |
| * that hctx won't be brought online. In this |
| * case, remap the current ctx to hctx[0] which |
| * is guaranteed to always have tags allocated |
| */ |
| q->mq_map[i] = 0; |
| } |
| |
| ctx = per_cpu_ptr(q->queue_ctx, i); |
| hctx = blk_mq_map_queue(q, i); |
| |
| cpumask_set_cpu(i, hctx->cpumask); |
| ctx->index_hw = hctx->nr_ctx; |
| hctx->ctxs[hctx->nr_ctx++] = ctx; |
| } |
| |
| mutex_unlock(&q->sysfs_lock); |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| /* |
| * If no software queues are mapped to this hardware queue, |
| * disable it and free the request entries. |
| */ |
| if (!hctx->nr_ctx) { |
| /* Never unmap queue 0. We need it as a |
| * fallback in case of a new remap fails |
| * allocation |
| */ |
| if (i && set->tags[i]) |
| blk_mq_free_map_and_requests(set, i); |
| |
| hctx->tags = NULL; |
| continue; |
| } |
| |
| hctx->tags = set->tags[i]; |
| WARN_ON(!hctx->tags); |
| |
| /* |
| * Set the map size to the number of mapped software queues. |
| * This is more accurate and more efficient than looping |
| * over all possibly mapped software queues. |
| */ |
| sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx); |
| |
| /* |
| * Initialize batch roundrobin counts |
| */ |
| hctx->next_cpu = cpumask_first(hctx->cpumask); |
| hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
| } |
| } |
| |
| /* |
| * Caller needs to ensure that we're either frozen/quiesced, or that |
| * the queue isn't live yet. |
| */ |
| static void queue_set_hctx_shared(struct request_queue *q, bool shared) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| int i; |
| |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (shared) { |
| if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) |
| atomic_inc(&q->shared_hctx_restart); |
| hctx->flags |= BLK_MQ_F_TAG_SHARED; |
| } else { |
| if (test_bit(BLK_MQ_S_SCHED_RESTART, &hctx->state)) |
| atomic_dec(&q->shared_hctx_restart); |
| hctx->flags &= ~BLK_MQ_F_TAG_SHARED; |
| } |
| } |
| } |
| |
| static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set, |
| bool shared) |
| { |
| struct request_queue *q; |
| |
| lockdep_assert_held(&set->tag_list_lock); |
| |
| list_for_each_entry(q, &set->tag_list, tag_set_list) { |
| blk_mq_freeze_queue(q); |
| queue_set_hctx_shared(q, shared); |
| blk_mq_unfreeze_queue(q); |
| } |
| } |
| |
| static void blk_mq_del_queue_tag_set(struct request_queue *q) |
| { |
| struct blk_mq_tag_set *set = q->tag_set; |
| |
| mutex_lock(&set->tag_list_lock); |
| list_del_rcu(&q->tag_set_list); |
| if (list_is_singular(&set->tag_list)) { |
| /* just transitioned to unshared */ |
| set->flags &= ~BLK_MQ_F_TAG_SHARED; |
| /* update existing queue */ |
| blk_mq_update_tag_set_depth(set, false); |
| } |
| mutex_unlock(&set->tag_list_lock); |
| synchronize_rcu(); |
| 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) |
| { |
| q->tag_set = set; |
| |
| mutex_lock(&set->tag_list_lock); |
| |
| /* Check to see if we're transitioning to shared (from 1 to 2 queues). */ |
| if (!list_empty(&set->tag_list) && !(set->flags & BLK_MQ_F_TAG_SHARED)) { |
| set->flags |= BLK_MQ_F_TAG_SHARED; |
| /* update existing queue */ |
| blk_mq_update_tag_set_depth(set, true); |
| } |
| if (set->flags & BLK_MQ_F_TAG_SHARED) |
| queue_set_hctx_shared(q, true); |
| list_add_tail_rcu(&q->tag_set_list, &set->tag_list); |
| |
| mutex_unlock(&set->tag_list_lock); |
| } |
| |
| /* |
| * 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; |
| unsigned int i; |
| |
| /* hctx kobj stays in hctx */ |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (!hctx) |
| continue; |
| kobject_put(&hctx->kobj); |
| } |
| |
| q->mq_map = NULL; |
| |
| kfree(q->queue_hw_ctx); |
| |
| /* |
| * release .mq_kobj and sw queue's kobject now because |
| * both share lifetime with request queue. |
| */ |
| blk_mq_sysfs_deinit(q); |
| |
| free_percpu(q->queue_ctx); |
| } |
| |
| struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set) |
| { |
| struct request_queue *uninit_q, *q; |
| |
| uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node); |
| if (!uninit_q) |
| return ERR_PTR(-ENOMEM); |
| |
| q = blk_mq_init_allocated_queue(set, uninit_q); |
| if (IS_ERR(q)) |
| blk_cleanup_queue(uninit_q); |
| |
| return q; |
| } |
| EXPORT_SYMBOL(blk_mq_init_queue); |
| |
| static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set) |
| { |
| int hw_ctx_size = sizeof(struct blk_mq_hw_ctx); |
| |
| BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx, queue_rq_srcu), |
| __alignof__(struct blk_mq_hw_ctx)) != |
| sizeof(struct blk_mq_hw_ctx)); |
| |
| if (tag_set->flags & BLK_MQ_F_BLOCKING) |
| hw_ctx_size += sizeof(struct srcu_struct); |
| |
| return hw_ctx_size; |
| } |
| |
| static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, |
| struct request_queue *q) |
| { |
| int i, j; |
| struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx; |
| |
| blk_mq_sysfs_unregister(q); |
| |
| /* protect against switching io scheduler */ |
| mutex_lock(&q->sysfs_lock); |
| for (i = 0; i < set->nr_hw_queues; i++) { |
| int node; |
| |
| if (hctxs[i]) |
| continue; |
| |
| node = blk_mq_hw_queue_to_node(q->mq_map, i); |
| hctxs[i] = kzalloc_node(blk_mq_hw_ctx_size(set), |
| GFP_KERNEL, node); |
| if (!hctxs[i]) |
| break; |
| |
| if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL, |
| node)) { |
| kfree(hctxs[i]); |
| hctxs[i] = NULL; |
| break; |
| } |
| |
| atomic_set(&hctxs[i]->nr_active, 0); |
| hctxs[i]->numa_node = node; |
| hctxs[i]->queue_num = i; |
| |
| if (blk_mq_init_hctx(q, set, hctxs[i], i)) { |
| free_cpumask_var(hctxs[i]->cpumask); |
| kfree(hctxs[i]); |
| hctxs[i] = NULL; |
| break; |
| } |
| blk_mq_hctx_kobj_init(hctxs[i]); |
| } |
| for (j = i; j < q->nr_hw_queues; j++) { |
| struct blk_mq_hw_ctx *hctx = hctxs[j]; |
| |
| if (hctx) { |
| if (hctx->tags) |
| blk_mq_free_map_and_requests(set, j); |
| blk_mq_exit_hctx(q, set, hctx, j); |
| kobject_put(&hctx->kobj); |
| hctxs[j] = NULL; |
| |
| } |
| } |
| q->nr_hw_queues = i; |
| mutex_unlock(&q->sysfs_lock); |
| blk_mq_sysfs_register(q); |
| } |
| |
| struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, |
| struct request_queue *q) |
| { |
| /* 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; |
| |
| q->queue_ctx = alloc_percpu(struct blk_mq_ctx); |
| if (!q->queue_ctx) |
| goto err_exit; |
| |
| /* init q->mq_kobj and sw queues' kobjects */ |
| blk_mq_sysfs_init(q); |
| |
| q->queue_hw_ctx = kzalloc_node(nr_cpu_ids * sizeof(*(q->queue_hw_ctx)), |
| GFP_KERNEL, set->numa_node); |
| if (!q->queue_hw_ctx) |
| goto err_percpu; |
| |
| q->mq_map = set->mq_map; |
| |
| 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->nr_queues = nr_cpu_ids; |
| |
| q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; |
| |
| if (!(set->flags & BLK_MQ_F_SG_MERGE)) |
| q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE; |
| |
| q->sg_reserved_size = INT_MAX; |
| |
| INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work); |
| INIT_LIST_HEAD(&q->requeue_list); |
| spin_lock_init(&q->requeue_lock); |
| |
| blk_queue_make_request(q, blk_mq_make_request); |
| |
| /* |
| * Do this after blk_queue_make_request() overrides it... |
| */ |
| q->nr_requests = set->queue_depth; |
| |
| /* |
| * Default to classic polling |
| */ |
| q->poll_nsec = -1; |
| |
| if (set->ops->complete) |
| blk_queue_softirq_done(q, set->ops->complete); |
| |
| blk_mq_init_cpu_queues(q, set->nr_hw_queues); |
| blk_mq_add_queue_tag_set(set, q); |
| blk_mq_map_swqueue(q); |
| |
| if (!(set->flags & BLK_MQ_F_NO_SCHED)) { |
| int ret; |
| |
| ret = blk_mq_sched_init(q); |
| if (ret) |
| return ERR_PTR(ret); |
| } |
| |
| return q; |
| |
| err_hctxs: |
| kfree(q->queue_hw_ctx); |
| err_percpu: |
| free_percpu(q->queue_ctx); |
| err_exit: |
| q->mq_ops = NULL; |
| return ERR_PTR(-ENOMEM); |
| } |
| EXPORT_SYMBOL(blk_mq_init_allocated_queue); |
| |
| void blk_mq_free_queue(struct request_queue *q) |
| { |
| struct blk_mq_tag_set *set = q->tag_set; |
| |
| blk_mq_del_queue_tag_set(q); |
| blk_mq_exit_hw_queues(q, set, set->nr_hw_queues); |
| } |
| |
| /* Basically redo blk_mq_init_queue with queue frozen */ |
| static void blk_mq_queue_reinit(struct request_queue *q) |
| { |
| WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth)); |
| |
| blk_mq_debugfs_unregister_hctxs(q); |
| blk_mq_sysfs_unregister(q); |
| |
| /* |
| * redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe |
| * we should change hctx numa_node according to new topology (this |
| * involves free and re-allocate memory, worthy doing?) |
| */ |
| |
| blk_mq_map_swqueue(q); |
| |
| blk_mq_sysfs_register(q); |
| blk_mq_debugfs_register_hctxs(q); |
| } |
| |
| static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) |
| { |
| int i; |
| |
| for (i = 0; i < set->nr_hw_queues; i++) |
| if (!__blk_mq_alloc_rq_map(set, i)) |
| goto out_unwind; |
| |
| return 0; |
| |
| out_unwind: |
| while (--i >= 0) |
| blk_mq_free_rq_map(set->tags[i]); |
| |
| return -ENOMEM; |
| } |
| |
| /* |
| * Allocate the request maps associated with this tag_set. Note that this |
| * may reduce the depth asked for, if memory is tight. set->queue_depth |
| * will be updated to reflect the allocated depth. |
| */ |
| static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) |
| { |
| unsigned int depth; |
| int err; |
| |
| depth = set->queue_depth; |
| do { |
| err = __blk_mq_alloc_rq_maps(set); |
| if (!err) |
| break; |
| |
| set->queue_depth >>= 1; |
| if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { |
| err = -ENOMEM; |
| break; |
| } |
| } while (set->queue_depth); |
| |
| if (!set->queue_depth || err) { |
| pr_err("blk-mq: failed to allocate request map\n"); |
| return -ENOMEM; |
| } |
| |
| if (depth != set->queue_depth) |
| pr_info("blk-mq: reduced tag depth (%u -> %u)\n", |
| depth, set->queue_depth); |
| |
| return 0; |
| } |
| |
| static int blk_mq_update_queue_map(struct blk_mq_tag_set *set) |
| { |
| if (set->ops->map_queues) { |
| int cpu; |
| /* |
| * 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->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_each_possible_cpu(cpu) |
| set->mq_map[cpu] = 0; |
| |
| return set->ops->map_queues(set); |
| } else |
| return blk_mq_map_queues(set); |
| } |
| |
| /* |
| * 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 if it 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 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->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 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->queue_depth = min(64U, set->queue_depth); |
| } |
| /* |
| * There is no use for more h/w queues than cpus. |
| */ |
| if (set->nr_hw_queues > nr_cpu_ids) |
| set->nr_hw_queues = nr_cpu_ids; |
| |
| set->tags = kzalloc_node(nr_cpu_ids * sizeof(struct blk_mq_tags *), |
| GFP_KERNEL, set->numa_node); |
| if (!set->tags) |
| return -ENOMEM; |
| |
| ret = -ENOMEM; |
| set->mq_map = kzalloc_node(sizeof(*set->mq_map) * nr_cpu_ids, |
| GFP_KERNEL, set->numa_node); |
| if (!set->mq_map) |
| goto out_free_tags; |
| |
| ret = blk_mq_update_queue_map(set); |
| if (ret) |
| goto out_free_mq_map; |
| |
| ret = blk_mq_alloc_rq_maps(set); |
| if (ret) |
| goto out_free_mq_map; |
| |
| mutex_init(&set->tag_list_lock); |
| INIT_LIST_HEAD(&set->tag_list); |
| |
| return 0; |
| |
| out_free_mq_map: |
| kfree(set->mq_map); |
| set->mq_map = NULL; |
| out_free_tags: |
| kfree(set->tags); |
| set->tags = NULL; |
| return ret; |
| } |
| EXPORT_SYMBOL(blk_mq_alloc_tag_set); |
| |
| void blk_mq_free_tag_set(struct blk_mq_tag_set *set) |
| { |
| int i; |
| |
| for (i = 0; i < nr_cpu_ids; i++) |
| blk_mq_free_map_and_requests(set, i); |
| |
| kfree(set->mq_map); |
| set->mq_map = NULL; |
| |
| kfree(set->tags); |
| set->tags = NULL; |
| } |
| EXPORT_SYMBOL(blk_mq_free_tag_set); |
| |
| int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) |
| { |
| struct blk_mq_tag_set *set = q->tag_set; |
| struct blk_mq_hw_ctx *hctx; |
| int i, ret; |
| |
| if (!set) |
| return -EINVAL; |
| |
| blk_mq_freeze_queue(q); |
| |
| ret = 0; |
| queue_for_each_hw_ctx(q, hctx, i) { |
| if (!hctx->tags) |
| continue; |
| /* |
| * If we're using an MQ scheduler, just update the scheduler |
| * queue depth. This is similar to what the old code would do. |
| */ |
| if (!hctx->sched_tags) { |
| ret = blk_mq_tag_update_depth(hctx, &hctx->tags, |
| min(nr, set->queue_depth), |
| false); |
| } else { |
| ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags, |
| nr, true); |
| } |
| if (ret) |
| break; |
| } |
| |
| if (!ret) |
| q->nr_requests = nr; |
| |
| blk_mq_unfreeze_queue(q); |
| |
| return ret; |
| } |
| |
| static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, |
| int nr_hw_queues) |
| { |
| struct request_queue *q; |
| |
| lockdep_assert_held(&set->tag_list_lock); |
| |
| if (nr_hw_queues > nr_cpu_ids) |
| nr_hw_queues = nr_cpu_ids; |
| if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues) |
| return; |
| |
| list_for_each_entry(q, &set->tag_list, tag_set_list) |
| blk_mq_freeze_queue(q); |
| |
| set->nr_hw_queues = nr_hw_queues; |
| 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_queue_reinit(q); |
| } |
| |
| list_for_each_entry(q, &set->tag_list, tag_set_list) |
| blk_mq_unfreeze_queue(q); |
| } |
| |
| void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) |
| { |
| mutex_lock(&set->tag_list_lock); |
| __blk_mq_update_nr_hw_queues(set, nr_hw_queues); |
| mutex_unlock(&set->tag_list_lock); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); |
| |
| /* Enable polling stats and return whether they were already enabled. */ |
| static bool blk_poll_stats_enable(struct request_queue *q) |
| { |
| if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || |
| test_and_set_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags)) |
| return true; |
| blk_stat_add_callback(q, q->poll_cb); |
| return false; |
| } |
| |
| static void blk_mq_poll_stats_start(struct request_queue *q) |
| { |
| /* |
| * We don't arm the callback if polling stats are not enabled or the |
| * callback is already active. |
| */ |
| if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || |
| blk_stat_is_active(q->poll_cb)) |
| return; |
| |
| blk_stat_activate_msecs(q->poll_cb, 100); |
| } |
| |
| static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb) |
| { |
| struct request_queue *q = cb->data; |
| int bucket; |
| |
| for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) { |
| if (cb->stat[bucket].nr_samples) |
| q->poll_stat[bucket] = cb->stat[bucket]; |
| } |
| } |
| |
| static unsigned long blk_mq_poll_nsecs(struct request_queue *q, |
| struct blk_mq_hw_ctx *hctx, |
| struct request *rq) |
| { |
| unsigned long ret = 0; |
| int bucket; |
| |
| /* |
| * If stats collection isn't on, don't sleep but turn it on for |
| * future users |
| */ |
| if (!blk_poll_stats_enable(q)) |
| return 0; |
| |
| /* |
| * As an optimistic guess, use half of the mean service time |
| * for this type of request. We can (and should) make this smarter. |
| * For instance, if the completion latencies are tight, we can |
| * get closer than just half the mean. This is especially |
| * important on devices where the completion latencies are longer |
| * than ~10 usec. We do use the stats for the relevant IO size |
| * if available which does lead to better estimates. |
| */ |
| bucket = blk_mq_poll_stats_bkt(rq); |
| if (bucket < 0) |
| return ret; |
| |
| if (q->poll_stat[bucket].nr_samples) |
| ret = (q->poll_stat[bucket].mean + 1) / 2; |
| |
| return ret; |
| } |
| |
| static bool blk_mq_poll_hybrid_sleep(struct request_queue *q, |
| struct blk_mq_hw_ctx *hctx, |
| struct request *rq) |
| { |
| struct hrtimer_sleeper hs; |
| enum hrtimer_mode mode; |
| unsigned int nsecs; |
| ktime_t kt; |
| |
| if (test_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags)) |
| return false; |
| |
| /* |
| * poll_nsec can be: |
| * |
| * -1: don't ever hybrid sleep |
| * 0: use half of prev avg |
| * >0: use this specific value |
| */ |
| if (q->poll_nsec == -1) |
| return false; |
| else if (q->poll_nsec > 0) |
| nsecs = q->poll_nsec; |
| else |
| nsecs = blk_mq_poll_nsecs(q, hctx, rq); |
| |
| if (!nsecs) |
| return false; |
| |
| set_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags); |
| |
| /* |
| * 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_on_stack(&hs.timer, CLOCK_MONOTONIC, mode); |
| hrtimer_set_expires(&hs.timer, kt); |
| |
| hrtimer_init_sleeper(&hs, current); |
| do { |
| if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags)) |
| break; |
| set_current_state(TASK_UNINTERRUPTIBLE); |
| hrtimer_start_expires(&hs.timer, mode); |
| if (hs.task) |
| io_schedule(); |
| hrtimer_cancel(&hs.timer); |
| mode = HRTIMER_MODE_ABS; |
| } while (hs.task && !signal_pending(current)); |
| |
| __set_current_state(TASK_RUNNING); |
| destroy_hrtimer_on_stack(&hs.timer); |
| return true; |
| } |
| |
| static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq) |
| { |
| struct request_queue *q = hctx->queue; |
| long state; |
| |
| /* |
| * If we sleep, have the caller restart the poll loop to reset |
| * the state. Like for the other success return cases, the |
| * caller is responsible for checking if the IO completed. If |
| * the IO isn't complete, we'll get called again and will go |
| * straight to the busy poll loop. |
| */ |
| if (blk_mq_poll_hybrid_sleep(q, hctx, rq)) |
| return true; |
| |
| hctx->poll_considered++; |
| |
| state = current->state; |
| while (!need_resched()) { |
| int ret; |
| |
| hctx->poll_invoked++; |
| |
| ret = q->mq_ops->poll(hctx, rq->tag); |
| if (ret > 0) { |
| hctx->poll_success++; |
| set_current_state(TASK_RUNNING); |
| return true; |
| } |
| |
| if (signal_pending_state(state, current)) |
| set_current_state(TASK_RUNNING); |
| |
| if (current->state == TASK_RUNNING) |
| return true; |
| if (ret < 0) |
| break; |
| cpu_relax(); |
| } |
| |
| return false; |
| } |
| |
| bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie) |
| { |
| struct blk_mq_hw_ctx *hctx; |
| struct blk_plug *plug; |
| struct request *rq; |
| |
| if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) || |
| !test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
| return false; |
| |
| plug = current->plug; |
| if (plug) |
| blk_flush_plug_list(plug, false); |
| |
| hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; |
| if (!blk_qc_t_is_internal(cookie)) |
| rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie)); |
| else { |
| rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie)); |
| /* |
| * With scheduling, if the request has completed, we'll |
| * get a NULL return here, as we clear the sched tag when |
| * that happens. The request still remains valid, like always, |
| * so we should be safe with just the NULL check. |
| */ |
| if (!rq) |
| return false; |
| } |
| |
| return __blk_mq_poll(hctx, rq); |
| } |
| EXPORT_SYMBOL_GPL(blk_mq_poll); |
| |
| static int __init blk_mq_init(void) |
| { |
| cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, |
| blk_mq_hctx_notify_dead); |
| return 0; |
| } |
| subsys_initcall(blk_mq_init); |