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4035 lines
100 KiB
4035 lines
100 KiB
// SPDX-License-Identifier: GPL-2.0 |
|
/* |
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* Block multiqueue core code |
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* |
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* Copyright (C) 2013-2014 Jens Axboe |
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* Copyright (C) 2013-2014 Christoph Hellwig |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/backing-dev.h> |
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#include <linux/bio.h> |
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#include <linux/blkdev.h> |
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#include <linux/kmemleak.h> |
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#include <linux/mm.h> |
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#include <linux/init.h> |
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#include <linux/slab.h> |
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#include <linux/workqueue.h> |
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#include <linux/smp.h> |
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#include <linux/llist.h> |
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#include <linux/list_sort.h> |
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#include <linux/cpu.h> |
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#include <linux/cache.h> |
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#include <linux/sched/sysctl.h> |
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#include <linux/sched/topology.h> |
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#include <linux/sched/signal.h> |
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#include <linux/delay.h> |
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#include <linux/crash_dump.h> |
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#include <linux/prefetch.h> |
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#include <linux/blk-crypto.h> |
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|
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#include <trace/events/block.h> |
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|
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#include <linux/blk-mq.h> |
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#include <linux/t10-pi.h> |
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#include "blk.h" |
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#include "blk-mq.h" |
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#include "blk-mq-debugfs.h" |
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#include "blk-mq-tag.h" |
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#include "blk-pm.h" |
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#include "blk-stat.h" |
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#include "blk-mq-sched.h" |
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#include "blk-rq-qos.h" |
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|
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static DEFINE_PER_CPU(struct llist_head, blk_cpu_done); |
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|
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static void blk_mq_poll_stats_start(struct request_queue *q); |
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static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb); |
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|
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static int blk_mq_poll_stats_bkt(const struct request *rq) |
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{ |
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int ddir, sectors, bucket; |
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|
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ddir = rq_data_dir(rq); |
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sectors = blk_rq_stats_sectors(rq); |
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|
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bucket = ddir + 2 * ilog2(sectors); |
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|
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if (bucket < 0) |
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return -1; |
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else if (bucket >= BLK_MQ_POLL_STATS_BKTS) |
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return ddir + BLK_MQ_POLL_STATS_BKTS - 2; |
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|
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return bucket; |
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} |
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|
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/* |
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* Check if any of the ctx, dispatch list or elevator |
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* have pending work in this hardware queue. |
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*/ |
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static bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx) |
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{ |
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return !list_empty_careful(&hctx->dispatch) || |
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sbitmap_any_bit_set(&hctx->ctx_map) || |
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blk_mq_sched_has_work(hctx); |
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} |
|
|
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/* |
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* Mark this ctx as having pending work in this hardware queue |
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*/ |
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static void blk_mq_hctx_mark_pending(struct blk_mq_hw_ctx *hctx, |
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struct blk_mq_ctx *ctx) |
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{ |
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const int bit = ctx->index_hw[hctx->type]; |
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|
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if (!sbitmap_test_bit(&hctx->ctx_map, bit)) |
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sbitmap_set_bit(&hctx->ctx_map, bit); |
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} |
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|
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static void blk_mq_hctx_clear_pending(struct blk_mq_hw_ctx *hctx, |
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struct blk_mq_ctx *ctx) |
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{ |
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const int bit = ctx->index_hw[hctx->type]; |
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|
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sbitmap_clear_bit(&hctx->ctx_map, bit); |
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} |
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|
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struct mq_inflight { |
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struct block_device *part; |
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unsigned int inflight[2]; |
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}; |
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|
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static bool blk_mq_check_inflight(struct blk_mq_hw_ctx *hctx, |
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struct request *rq, void *priv, |
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bool reserved) |
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{ |
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struct mq_inflight *mi = priv; |
|
|
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if ((!mi->part->bd_partno || rq->part == mi->part) && |
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blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT) |
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mi->inflight[rq_data_dir(rq)]++; |
|
|
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return true; |
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} |
|
|
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unsigned int blk_mq_in_flight(struct request_queue *q, |
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struct block_device *part) |
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{ |
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struct mq_inflight mi = { .part = part }; |
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|
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blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi); |
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|
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return mi.inflight[0] + mi.inflight[1]; |
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} |
|
|
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void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part, |
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unsigned int inflight[2]) |
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{ |
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struct mq_inflight mi = { .part = part }; |
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|
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blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi); |
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inflight[0] = mi.inflight[0]; |
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inflight[1] = mi.inflight[1]; |
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} |
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|
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void blk_freeze_queue_start(struct request_queue *q) |
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{ |
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mutex_lock(&q->mq_freeze_lock); |
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if (++q->mq_freeze_depth == 1) { |
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percpu_ref_kill(&q->q_usage_counter); |
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mutex_unlock(&q->mq_freeze_lock); |
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if (queue_is_mq(q)) |
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blk_mq_run_hw_queues(q, false); |
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} else { |
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mutex_unlock(&q->mq_freeze_lock); |
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} |
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} |
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EXPORT_SYMBOL_GPL(blk_freeze_queue_start); |
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|
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void blk_mq_freeze_queue_wait(struct request_queue *q) |
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{ |
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wait_event(q->mq_freeze_wq, percpu_ref_is_zero(&q->q_usage_counter)); |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait); |
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|
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int blk_mq_freeze_queue_wait_timeout(struct request_queue *q, |
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unsigned long timeout) |
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{ |
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return wait_event_timeout(q->mq_freeze_wq, |
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percpu_ref_is_zero(&q->q_usage_counter), |
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timeout); |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_wait_timeout); |
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|
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/* |
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* Guarantee no request is in use, so we can change any data structure of |
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* the queue afterward. |
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*/ |
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void blk_freeze_queue(struct request_queue *q) |
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{ |
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/* |
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* In the !blk_mq case we are only calling this to kill the |
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* q_usage_counter, otherwise this increases the freeze depth |
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* and waits for it to return to zero. For this reason there is |
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* no blk_unfreeze_queue(), and blk_freeze_queue() is not |
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* exported to drivers as the only user for unfreeze is blk_mq. |
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*/ |
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blk_freeze_queue_start(q); |
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blk_mq_freeze_queue_wait(q); |
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} |
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|
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void blk_mq_freeze_queue(struct request_queue *q) |
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{ |
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/* |
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* ...just an alias to keep freeze and unfreeze actions balanced |
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* in the blk_mq_* namespace |
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*/ |
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blk_freeze_queue(q); |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_freeze_queue); |
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|
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void __blk_mq_unfreeze_queue(struct request_queue *q, bool force_atomic) |
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{ |
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mutex_lock(&q->mq_freeze_lock); |
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if (force_atomic) |
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q->q_usage_counter.data->force_atomic = true; |
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q->mq_freeze_depth--; |
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WARN_ON_ONCE(q->mq_freeze_depth < 0); |
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if (!q->mq_freeze_depth) { |
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percpu_ref_resurrect(&q->q_usage_counter); |
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wake_up_all(&q->mq_freeze_wq); |
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} |
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mutex_unlock(&q->mq_freeze_lock); |
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} |
|
|
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void blk_mq_unfreeze_queue(struct request_queue *q) |
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{ |
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__blk_mq_unfreeze_queue(q, false); |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); |
|
|
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/* |
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* FIXME: replace the scsi_internal_device_*block_nowait() calls in the |
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* mpt3sas driver such that this function can be removed. |
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*/ |
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void blk_mq_quiesce_queue_nowait(struct request_queue *q) |
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{ |
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blk_queue_flag_set(QUEUE_FLAG_QUIESCED, q); |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); |
|
|
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/** |
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* blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished |
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* @q: request queue. |
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* |
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* Note: this function does not prevent that the struct request end_io() |
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* callback function is invoked. Once this function is returned, we make |
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* sure no dispatch can happen until the queue is unquiesced via |
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* blk_mq_unquiesce_queue(). |
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*/ |
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void blk_mq_quiesce_queue(struct request_queue *q) |
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{ |
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struct blk_mq_hw_ctx *hctx; |
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unsigned int i; |
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bool rcu = false; |
|
|
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blk_mq_quiesce_queue_nowait(q); |
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|
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queue_for_each_hw_ctx(q, hctx, i) { |
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if (hctx->flags & BLK_MQ_F_BLOCKING) |
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synchronize_srcu(hctx->srcu); |
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else |
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rcu = true; |
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} |
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if (rcu) |
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synchronize_rcu(); |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue); |
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|
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/* |
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* blk_mq_unquiesce_queue() - counterpart of blk_mq_quiesce_queue() |
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* @q: request queue. |
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* |
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* This function recovers queue into the state before quiescing |
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* which is done by blk_mq_quiesce_queue. |
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*/ |
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void blk_mq_unquiesce_queue(struct request_queue *q) |
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{ |
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blk_queue_flag_clear(QUEUE_FLAG_QUIESCED, q); |
|
|
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/* dispatch requests which are inserted during quiescing */ |
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blk_mq_run_hw_queues(q, true); |
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} |
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EXPORT_SYMBOL_GPL(blk_mq_unquiesce_queue); |
|
|
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void blk_mq_wake_waiters(struct request_queue *q) |
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{ |
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struct blk_mq_hw_ctx *hctx; |
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unsigned int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) |
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if (blk_mq_hw_queue_mapped(hctx)) |
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blk_mq_tag_wakeup_all(hctx->tags, true); |
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} |
|
|
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/* |
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* Only need start/end time stamping if we have iostat or |
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* blk stats enabled, or using an IO scheduler. |
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*/ |
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static inline bool blk_mq_need_time_stamp(struct request *rq) |
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{ |
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return (rq->rq_flags & (RQF_IO_STAT | RQF_STATS)) || rq->q->elevator; |
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} |
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|
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static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data, |
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unsigned int tag, u64 alloc_time_ns) |
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{ |
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struct blk_mq_tags *tags = blk_mq_tags_from_data(data); |
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struct request *rq = tags->static_rqs[tag]; |
|
|
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if (data->q->elevator) { |
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rq->tag = BLK_MQ_NO_TAG; |
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rq->internal_tag = tag; |
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} else { |
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rq->tag = tag; |
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rq->internal_tag = BLK_MQ_NO_TAG; |
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} |
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|
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/* csd/requeue_work/fifo_time is initialized before use */ |
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rq->q = data->q; |
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rq->mq_ctx = data->ctx; |
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rq->mq_hctx = data->hctx; |
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rq->rq_flags = 0; |
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rq->cmd_flags = data->cmd_flags; |
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if (data->flags & BLK_MQ_REQ_PM) |
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rq->rq_flags |= RQF_PM; |
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if (blk_queue_io_stat(data->q)) |
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rq->rq_flags |= RQF_IO_STAT; |
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INIT_LIST_HEAD(&rq->queuelist); |
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INIT_HLIST_NODE(&rq->hash); |
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RB_CLEAR_NODE(&rq->rb_node); |
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rq->rq_disk = NULL; |
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rq->part = NULL; |
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#ifdef CONFIG_BLK_RQ_ALLOC_TIME |
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rq->alloc_time_ns = alloc_time_ns; |
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#endif |
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if (blk_mq_need_time_stamp(rq)) |
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rq->start_time_ns = ktime_get_ns(); |
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else |
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rq->start_time_ns = 0; |
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rq->io_start_time_ns = 0; |
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rq->stats_sectors = 0; |
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rq->nr_phys_segments = 0; |
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#if defined(CONFIG_BLK_DEV_INTEGRITY) |
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rq->nr_integrity_segments = 0; |
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#endif |
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blk_crypto_rq_set_defaults(rq); |
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/* tag was already set */ |
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WRITE_ONCE(rq->deadline, 0); |
|
|
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rq->timeout = 0; |
|
|
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rq->end_io = NULL; |
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rq->end_io_data = NULL; |
|
|
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data->ctx->rq_dispatched[op_is_sync(data->cmd_flags)]++; |
|
refcount_set(&rq->ref, 1); |
|
|
|
if (!op_is_flush(data->cmd_flags)) { |
|
struct elevator_queue *e = data->q->elevator; |
|
|
|
rq->elv.icq = NULL; |
|
if (e && e->type->ops.prepare_request) { |
|
if (e->type->icq_cache) |
|
blk_mq_sched_assign_ioc(rq); |
|
|
|
e->type->ops.prepare_request(rq); |
|
rq->rq_flags |= RQF_ELVPRIV; |
|
} |
|
} |
|
|
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data->hctx->queued++; |
|
return rq; |
|
} |
|
|
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static struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data) |
|
{ |
|
struct request_queue *q = data->q; |
|
struct elevator_queue *e = q->elevator; |
|
u64 alloc_time_ns = 0; |
|
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 (e) { |
|
/* |
|
* 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 (!e) |
|
blk_mq_tag_busy(data->hctx); |
|
|
|
/* |
|
* 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, tag, alloc_time_ns); |
|
} |
|
|
|
struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op, |
|
blk_mq_req_flags_t flags) |
|
{ |
|
struct blk_mq_alloc_data data = { |
|
.q = q, |
|
.flags = flags, |
|
.cmd_flags = op, |
|
}; |
|
struct request *rq; |
|
int ret; |
|
|
|
ret = blk_queue_enter(q, flags); |
|
if (ret) |
|
return ERR_PTR(ret); |
|
|
|
rq = __blk_mq_alloc_request(&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, |
|
unsigned int op, blk_mq_req_flags_t flags, unsigned int hctx_idx) |
|
{ |
|
struct blk_mq_alloc_data data = { |
|
.q = q, |
|
.flags = flags, |
|
.cmd_flags = op, |
|
}; |
|
u64 alloc_time_ns = 0; |
|
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 | 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 = q->queue_hw_ctx[hctx_idx]; |
|
if (!blk_mq_hw_queue_mapped(data.hctx)) |
|
goto out_queue_exit; |
|
cpu = cpumask_first_and(data.hctx->cpumask, cpu_online_mask); |
|
data.ctx = __blk_mq_get_ctx(q, cpu); |
|
|
|
if (!q->elevator) |
|
blk_mq_tag_busy(data.hctx); |
|
|
|
ret = -EWOULDBLOCK; |
|
tag = blk_mq_get_tag(&data); |
|
if (tag == BLK_MQ_NO_TAG) |
|
goto out_queue_exit; |
|
return blk_mq_rq_ctx_init(&data, tag, alloc_time_ns); |
|
|
|
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->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; |
|
struct elevator_queue *e = q->elevator; |
|
struct blk_mq_ctx *ctx = rq->mq_ctx; |
|
struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
|
|
|
if (rq->rq_flags & RQF_ELVPRIV) { |
|
if (e && e->type->ops.finish_request) |
|
e->type->ops.finish_request(rq); |
|
if (rq->elv.icq) { |
|
put_io_context(rq->elv.icq->ioc); |
|
rq->elv.icq = NULL; |
|
} |
|
} |
|
|
|
ctx->rq_completed[rq_is_sync(rq)]++; |
|
if (rq->rq_flags & RQF_MQ_INFLIGHT) |
|
__blk_mq_dec_active_requests(hctx); |
|
|
|
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 (refcount_dec_and_test(&rq->ref)) |
|
__blk_mq_free_request(rq); |
|
} |
|
EXPORT_SYMBOL_GPL(blk_mq_free_request); |
|
|
|
inline void __blk_mq_end_request(struct request *rq, blk_status_t error) |
|
{ |
|
u64 now = 0; |
|
|
|
if (blk_mq_need_time_stamp(rq)) |
|
now = ktime_get_ns(); |
|
|
|
if (rq->rq_flags & RQF_STATS) { |
|
blk_mq_poll_stats_start(rq->q); |
|
blk_stat_add(rq, now); |
|
} |
|
|
|
blk_mq_sched_completed_request(rq, now); |
|
|
|
blk_account_io_done(rq, now); |
|
|
|
if (rq->end_io) { |
|
rq_qos_done(rq->q, rq); |
|
rq->end_io(rq, error); |
|
} else { |
|
blk_mq_free_request(rq); |
|
} |
|
} |
|
EXPORT_SYMBOL(__blk_mq_end_request); |
|
|
|
void blk_mq_end_request(struct request *rq, blk_status_t error) |
|
{ |
|
if (blk_update_request(rq, error, blk_rq_bytes(rq))) |
|
BUG(); |
|
__blk_mq_end_request(rq, error); |
|
} |
|
EXPORT_SYMBOL(blk_mq_end_request); |
|
|
|
static void blk_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 a polled request, always complete locallly, it's pointless |
|
* to redirect the completion. |
|
*/ |
|
if (rq->cmd_flags & REQ_HIPRI) |
|
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); |
|
|
|
static void hctx_unlock(struct blk_mq_hw_ctx *hctx, int srcu_idx) |
|
__releases(hctx->srcu) |
|
{ |
|
if (!(hctx->flags & BLK_MQ_F_BLOCKING)) |
|
rcu_read_unlock(); |
|
else |
|
srcu_read_unlock(hctx->srcu, srcu_idx); |
|
} |
|
|
|
static void hctx_lock(struct blk_mq_hw_ctx *hctx, int *srcu_idx) |
|
__acquires(hctx->srcu) |
|
{ |
|
if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { |
|
/* shut up gcc false positive */ |
|
*srcu_idx = 0; |
|
rcu_read_lock(); |
|
} else |
|
*srcu_idx = srcu_read_lock(hctx->srcu); |
|
} |
|
|
|
/** |
|
* blk_mq_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 |
|
} |
|
EXPORT_SYMBOL(blk_mq_start_request); |
|
|
|
static void __blk_mq_requeue_request(struct request *rq) |
|
{ |
|
struct request_queue *q = rq->q; |
|
|
|
blk_mq_put_driver_tag(rq); |
|
|
|
trace_block_rq_requeue(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); |
|
|
|
BUG_ON(!list_empty(&rq->queuelist)); |
|
blk_mq_add_to_requeue_list(rq, true, kick_requeue_list); |
|
} |
|
EXPORT_SYMBOL(blk_mq_requeue_request); |
|
|
|
static void blk_mq_requeue_work(struct work_struct *work) |
|
{ |
|
struct request_queue *q = |
|
container_of(work, struct request_queue, requeue_work.work); |
|
LIST_HEAD(rq_list); |
|
struct request *rq, *next; |
|
|
|
spin_lock_irq(&q->requeue_lock); |
|
list_splice_init(&q->requeue_list, &rq_list); |
|
spin_unlock_irq(&q->requeue_lock); |
|
|
|
list_for_each_entry_safe(rq, next, &rq_list, queuelist) { |
|
if (!(rq->rq_flags & (RQF_SOFTBARRIER | RQF_DONTPREP))) |
|
continue; |
|
|
|
rq->rq_flags &= ~RQF_SOFTBARRIER; |
|
list_del_init(&rq->queuelist); |
|
/* |
|
* If RQF_DONTPREP, rq has contained some driver specific |
|
* data, so insert it to hctx dispatch list to avoid any |
|
* merge. |
|
*/ |
|
if (rq->rq_flags & RQF_DONTPREP) |
|
blk_mq_request_bypass_insert(rq, false, false); |
|
else |
|
blk_mq_sched_insert_request(rq, true, false, false); |
|
} |
|
|
|
while (!list_empty(&rq_list)) { |
|
rq = list_entry(rq_list.next, struct request, queuelist); |
|
list_del_init(&rq->queuelist); |
|
blk_mq_sched_insert_request(rq, false, false, false); |
|
} |
|
|
|
blk_mq_run_hw_queues(q, false); |
|
} |
|
|
|
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head, |
|
bool kick_requeue_list) |
|
{ |
|
struct request_queue *q = rq->q; |
|
unsigned long flags; |
|
|
|
/* |
|
* We abuse this flag that is otherwise used by the I/O scheduler to |
|
* request head insertion from the workqueue. |
|
*/ |
|
BUG_ON(rq->rq_flags & RQF_SOFTBARRIER); |
|
|
|
spin_lock_irqsave(&q->requeue_lock, flags); |
|
if (at_head) { |
|
rq->rq_flags |= RQF_SOFTBARRIER; |
|
list_add(&rq->queuelist, &q->requeue_list); |
|
} else { |
|
list_add_tail(&rq->queuelist, &q->requeue_list); |
|
} |
|
spin_unlock_irqrestore(&q->requeue_lock, flags); |
|
|
|
if (kick_requeue_list) |
|
blk_mq_kick_requeue_list(q); |
|
} |
|
|
|
void blk_mq_kick_requeue_list(struct request_queue *q) |
|
{ |
|
kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, 0); |
|
} |
|
EXPORT_SYMBOL(blk_mq_kick_requeue_list); |
|
|
|
void blk_mq_delay_kick_requeue_list(struct request_queue *q, |
|
unsigned long msecs) |
|
{ |
|
kblockd_mod_delayed_work_on(WORK_CPU_UNBOUND, &q->requeue_work, |
|
msecs_to_jiffies(msecs)); |
|
} |
|
EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list); |
|
|
|
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) |
|
{ |
|
if (tag < tags->nr_tags) { |
|
prefetch(tags->rqs[tag]); |
|
return tags->rqs[tag]; |
|
} |
|
|
|
return NULL; |
|
} |
|
EXPORT_SYMBOL(blk_mq_tag_to_rq); |
|
|
|
static bool blk_mq_rq_inflight(struct blk_mq_hw_ctx *hctx, struct request *rq, |
|
void *priv, bool reserved) |
|
{ |
|
/* |
|
* If we find a request that isn't idle and the queue matches, |
|
* we know the queue is busy. Return false to stop the iteration. |
|
*/ |
|
if (blk_mq_request_started(rq) && rq->q == hctx->queue) { |
|
bool *busy = priv; |
|
|
|
*busy = true; |
|
return false; |
|
} |
|
|
|
return true; |
|
} |
|
|
|
bool blk_mq_queue_inflight(struct request_queue *q) |
|
{ |
|
bool busy = false; |
|
|
|
blk_mq_queue_tag_busy_iter(q, blk_mq_rq_inflight, &busy); |
|
return busy; |
|
} |
|
EXPORT_SYMBOL_GPL(blk_mq_queue_inflight); |
|
|
|
static void blk_mq_rq_timed_out(struct request *req, bool reserved) |
|
{ |
|
req->rq_flags |= RQF_TIMED_OUT; |
|
if (req->q->mq_ops->timeout) { |
|
enum blk_eh_timer_return ret; |
|
|
|
ret = req->q->mq_ops->timeout(req, reserved); |
|
if (ret == BLK_EH_DONE) |
|
return; |
|
WARN_ON_ONCE(ret != BLK_EH_RESET_TIMER); |
|
} |
|
|
|
blk_add_timer(req); |
|
} |
|
|
|
static bool blk_mq_req_expired(struct request *rq, unsigned long *next) |
|
{ |
|
unsigned long deadline; |
|
|
|
if (blk_mq_rq_state(rq) != MQ_RQ_IN_FLIGHT) |
|
return false; |
|
if (rq->rq_flags & RQF_TIMED_OUT) |
|
return false; |
|
|
|
deadline = READ_ONCE(rq->deadline); |
|
if (time_after_eq(jiffies, deadline)) |
|
return true; |
|
|
|
if (*next == 0) |
|
*next = deadline; |
|
else if (time_after(*next, deadline)) |
|
*next = deadline; |
|
return false; |
|
} |
|
|
|
void blk_mq_put_rq_ref(struct request *rq) |
|
{ |
|
if (is_flush_rq(rq)) |
|
rq->end_io(rq, 0); |
|
else if (refcount_dec_and_test(&rq->ref)) |
|
__blk_mq_free_request(rq); |
|
} |
|
|
|
static bool blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, |
|
struct request *rq, void *priv, bool reserved) |
|
{ |
|
unsigned long *next = 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, next)) |
|
blk_mq_rq_timed_out(rq, reserved); |
|
return true; |
|
} |
|
|
|
static void blk_mq_timeout_work(struct work_struct *work) |
|
{ |
|
struct request_queue *q = |
|
container_of(work, struct request_queue, timeout_work); |
|
unsigned long next = 0; |
|
struct blk_mq_hw_ctx *hctx; |
|
int i; |
|
|
|
/* A deadlock might occur if a request is stuck requiring a |
|
* timeout at the same time a queue freeze is waiting |
|
* completion, since the timeout code would not be able to |
|
* acquire the queue reference here. |
|
* |
|
* That's why we don't use blk_queue_enter here; instead, we use |
|
* percpu_ref_tryget directly, because we need to be able to |
|
* obtain a reference even in the short window between the queue |
|
* starting to freeze, by dropping the first reference in |
|
* blk_freeze_queue_start, and the moment the last request is |
|
* consumed, marked by the instant q_usage_counter reaches |
|
* zero. |
|
*/ |
|
if (!percpu_ref_tryget(&q->q_usage_counter)) |
|
return; |
|
|
|
blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &next); |
|
|
|
if (next != 0) { |
|
mod_timer(&q->timeout, next); |
|
} else { |
|
/* |
|
* Request timeouts are handled as a forward rolling timer. If |
|
* we end up here it means that no requests are pending and |
|
* also that no request has been pending for a while. Mark |
|
* each hctx as idle. |
|
*/ |
|
queue_for_each_hw_ctx(q, hctx, i) { |
|
/* the hctx may be unmapped, so check it here */ |
|
if (blk_mq_hw_queue_mapped(hctx)) |
|
blk_mq_tag_idle(hctx); |
|
} |
|
} |
|
blk_queue_exit(q); |
|
} |
|
|
|
struct flush_busy_ctx_data { |
|
struct blk_mq_hw_ctx *hctx; |
|
struct list_head *list; |
|
}; |
|
|
|
static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data) |
|
{ |
|
struct flush_busy_ctx_data *flush_data = data; |
|
struct blk_mq_hw_ctx *hctx = flush_data->hctx; |
|
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; |
|
enum hctx_type type = hctx->type; |
|
|
|
spin_lock(&ctx->lock); |
|
list_splice_tail_init(&ctx->rq_lists[type], flush_data->list); |
|
sbitmap_clear_bit(sb, bitnr); |
|
spin_unlock(&ctx->lock); |
|
return true; |
|
} |
|
|
|
/* |
|
* Process software queues that have been marked busy, splicing them |
|
* to the for-dispatch |
|
*/ |
|
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list) |
|
{ |
|
struct flush_busy_ctx_data data = { |
|
.hctx = hctx, |
|
.list = list, |
|
}; |
|
|
|
sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data); |
|
} |
|
EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs); |
|
|
|
struct dispatch_rq_data { |
|
struct blk_mq_hw_ctx *hctx; |
|
struct request *rq; |
|
}; |
|
|
|
static bool dispatch_rq_from_ctx(struct sbitmap *sb, unsigned int bitnr, |
|
void *data) |
|
{ |
|
struct dispatch_rq_data *dispatch_data = data; |
|
struct blk_mq_hw_ctx *hctx = dispatch_data->hctx; |
|
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr]; |
|
enum hctx_type type = hctx->type; |
|
|
|
spin_lock(&ctx->lock); |
|
if (!list_empty(&ctx->rq_lists[type])) { |
|
dispatch_data->rq = list_entry_rq(ctx->rq_lists[type].next); |
|
list_del_init(&dispatch_data->rq->queuelist); |
|
if (list_empty(&ctx->rq_lists[type])) |
|
sbitmap_clear_bit(sb, bitnr); |
|
} |
|
spin_unlock(&ctx->lock); |
|
|
|
return !dispatch_data->rq; |
|
} |
|
|
|
struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx, |
|
struct blk_mq_ctx *start) |
|
{ |
|
unsigned off = start ? start->index_hw[hctx->type] : 0; |
|
struct dispatch_rq_data data = { |
|
.hctx = hctx, |
|
.rq = NULL, |
|
}; |
|
|
|
__sbitmap_for_each_set(&hctx->ctx_map, off, |
|
dispatch_rq_from_ctx, &data); |
|
|
|
return data.rq; |
|
} |
|
|
|
static inline unsigned int queued_to_index(unsigned int queued) |
|
{ |
|
if (!queued) |
|
return 0; |
|
|
|
return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1); |
|
} |
|
|
|
static bool __blk_mq_get_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 request *rq) |
|
{ |
|
struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
|
|
|
if (rq->tag == BLK_MQ_NO_TAG && !__blk_mq_get_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 = hctx->tags->bitmap_tags; |
|
struct wait_queue_head *wq; |
|
wait_queue_entry_t *wait; |
|
bool ret; |
|
|
|
if (!(hctx->flags & BLK_MQ_F_TAG_QUEUE_SHARED)) { |
|
blk_mq_sched_mark_restart_hctx(hctx); |
|
|
|
/* |
|
* It's possible that a tag was freed in the window between the |
|
* allocation failure and adding the hardware queue to the wait |
|
* queue. |
|
* |
|
* Don't clear RESTART here, someone else could have set it. |
|
* At most this will cost an extra queue run. |
|
*/ |
|
return blk_mq_get_driver_tag(rq); |
|
} |
|
|
|
wait = &hctx->dispatch_wait; |
|
if (!list_empty_careful(&wait->entry)) |
|
return false; |
|
|
|
wq = &bt_wait_ptr(sbq, hctx)->wait; |
|
|
|
spin_lock_irq(&wq->lock); |
|
spin_lock(&hctx->dispatch_wait_lock); |
|
if (!list_empty(&wait->entry)) { |
|
spin_unlock(&hctx->dispatch_wait_lock); |
|
spin_unlock_irq(&wq->lock); |
|
return false; |
|
} |
|
|
|
atomic_inc(&sbq->ws_active); |
|
wait->flags &= ~WQ_FLAG_EXCLUSIVE; |
|
__add_wait_queue(wq, wait); |
|
|
|
/* |
|
* It's possible that a tag was freed in the window between the |
|
* allocation failure and adding the hardware queue to the wait |
|
* queue. |
|
*/ |
|
ret = blk_mq_get_driver_tag(rq); |
|
if (!ret) { |
|
spin_unlock(&hctx->dispatch_wait_lock); |
|
spin_unlock_irq(&wq->lock); |
|
return false; |
|
} |
|
|
|
/* |
|
* We got a tag, remove ourselves from the wait queue to ensure |
|
* someone else gets the wakeup. |
|
*/ |
|
list_del_init(&wait->entry); |
|
atomic_dec(&sbq->ws_active); |
|
spin_unlock(&hctx->dispatch_wait_lock); |
|
spin_unlock_irq(&wq->lock); |
|
|
|
return true; |
|
} |
|
|
|
#define BLK_MQ_DISPATCH_BUSY_EWMA_WEIGHT 8 |
|
#define BLK_MQ_DISPATCH_BUSY_EWMA_FACTOR 4 |
|
/* |
|
* Update dispatch busy with the Exponential Weighted Moving Average(EWMA): |
|
* - EWMA is one simple way to compute running average value |
|
* - weight(7/8 and 1/8) is applied so that it can decrease exponentially |
|
* - take 4 as factor for avoiding to get too small(0) result, and this |
|
* factor doesn't matter because EWMA decreases exponentially |
|
*/ |
|
static void blk_mq_update_dispatch_busy(struct blk_mq_hw_ctx *hctx, bool busy) |
|
{ |
|
unsigned int ewma; |
|
|
|
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); |
|
|
|
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: |
|
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); |
|
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); |
|
|
|
hctx->dispatched[queued_to_index(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) && 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); |
|
bool no_budget_avail = prep == PREP_DISPATCH_NO_BUDGET; |
|
|
|
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 and SCHED_RESTART is set. |
|
*/ |
|
needs_restart = blk_mq_sched_needs_restart(hctx); |
|
if (!needs_restart || |
|
(no_tag && list_empty_careful(&hctx->dispatch_wait.entry))) |
|
blk_mq_run_hw_queue(hctx, true); |
|
else if (needs_restart && (ret == BLK_STS_RESOURCE || |
|
no_budget_avail)) |
|
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) |
|
{ |
|
int srcu_idx; |
|
|
|
/* |
|
* We can't run the queue inline with ints disabled. Ensure that |
|
* we catch bad users of this early. |
|
*/ |
|
WARN_ON_ONCE(in_interrupt()); |
|
|
|
might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); |
|
|
|
hctx_lock(hctx, &srcu_idx); |
|
blk_mq_sched_dispatch_requests(hctx); |
|
hctx_unlock(hctx, srcu_idx); |
|
} |
|
|
|
static inline int blk_mq_first_mapped_cpu(struct blk_mq_hw_ctx *hctx) |
|
{ |
|
int cpu = cpumask_first_and(hctx->cpumask, cpu_online_mask); |
|
|
|
if (cpu >= nr_cpu_ids) |
|
cpu = cpumask_first(hctx->cpumask); |
|
return cpu; |
|
} |
|
|
|
/* |
|
* It'd be great if the workqueue API had a way to pass |
|
* in a mask and had some smarts for more clever placement. |
|
* For now we just round-robin here, switching for every |
|
* BLK_MQ_CPU_WORK_BATCH queued items. |
|
*/ |
|
static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx) |
|
{ |
|
bool tried = false; |
|
int next_cpu = hctx->next_cpu; |
|
|
|
if (hctx->queue->nr_hw_queues == 1) |
|
return WORK_CPU_UNBOUND; |
|
|
|
if (--hctx->next_cpu_batch <= 0) { |
|
select_cpu: |
|
next_cpu = cpumask_next_and(next_cpu, hctx->cpumask, |
|
cpu_online_mask); |
|
if (next_cpu >= nr_cpu_ids) |
|
next_cpu = blk_mq_first_mapped_cpu(hctx); |
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
|
} |
|
|
|
/* |
|
* Do unbound schedule if we can't find a online CPU for this hctx, |
|
* and it should only happen in the path of handling CPU DEAD. |
|
*/ |
|
if (!cpu_online(next_cpu)) { |
|
if (!tried) { |
|
tried = true; |
|
goto select_cpu; |
|
} |
|
|
|
/* |
|
* Make sure to re-select CPU next time once after CPUs |
|
* in hctx->cpumask become online again. |
|
*/ |
|
hctx->next_cpu = next_cpu; |
|
hctx->next_cpu_batch = 1; |
|
return WORK_CPU_UNBOUND; |
|
} |
|
|
|
hctx->next_cpu = next_cpu; |
|
return next_cpu; |
|
} |
|
|
|
/** |
|
* __blk_mq_delay_run_hw_queue - Run (or schedule to run) a hardware queue. |
|
* @hctx: Pointer to the hardware queue to run. |
|
* @async: If we want to run the queue asynchronously. |
|
* @msecs: 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)) { |
|
int cpu = get_cpu(); |
|
if (cpumask_test_cpu(cpu, hctx->cpumask)) { |
|
__blk_mq_run_hw_queue(hctx); |
|
put_cpu(); |
|
return; |
|
} |
|
|
|
put_cpu(); |
|
} |
|
|
|
kblockd_mod_delayed_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work, |
|
msecs_to_jiffies(msecs)); |
|
} |
|
|
|
/** |
|
* blk_mq_delay_run_hw_queue - Run a hardware queue asynchronously. |
|
* @hctx: Pointer to the hardware queue to run. |
|
* @msecs: 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) |
|
{ |
|
int srcu_idx; |
|
bool need_run; |
|
|
|
/* |
|
* When queue is quiesced, we may be switching io scheduler, or |
|
* updating nr_hw_queues, or other things, and we can't run queue |
|
* any more, even __blk_mq_hctx_has_pending() can't be called safely. |
|
* |
|
* And queue will be rerun in blk_mq_unquiesce_queue() if it is |
|
* quiesced. |
|
*/ |
|
hctx_lock(hctx, &srcu_idx); |
|
need_run = !blk_queue_quiesced(hctx->queue) && |
|
blk_mq_hctx_has_pending(hctx); |
|
hctx_unlock(hctx, srcu_idx); |
|
|
|
if (need_run) |
|
__blk_mq_delay_run_hw_queue(hctx, async, 0); |
|
} |
|
EXPORT_SYMBOL(blk_mq_run_hw_queue); |
|
|
|
/* |
|
* Is the request queue handled by an IO scheduler that does not respect |
|
* hardware queues when dispatching? |
|
*/ |
|
static bool blk_mq_has_sqsched(struct request_queue *q) |
|
{ |
|
struct elevator_queue *e = q->elevator; |
|
|
|
if (e && e->type->ops.dispatch_request && |
|
!(e->type->elevator_features & ELEVATOR_F_MQ_AWARE)) |
|
return true; |
|
return false; |
|
} |
|
|
|
/* |
|
* 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_hw_ctx *hctx; |
|
|
|
/* |
|
* 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. |
|
*/ |
|
hctx = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT, |
|
raw_smp_processor_id()); |
|
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; |
|
int i; |
|
|
|
sq_hctx = NULL; |
|
if (blk_mq_has_sqsched(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; |
|
int i; |
|
|
|
sq_hctx = NULL; |
|
if (blk_mq_has_sqsched(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_delay_run_hw_queue(hctx, msecs); |
|
} |
|
} |
|
EXPORT_SYMBOL(blk_mq_delay_run_hw_queues); |
|
|
|
/** |
|
* blk_mq_queue_stopped() - check whether one or more hctxs have been stopped |
|
* @q: request queue. |
|
* |
|
* The caller is responsible for serializing this function against |
|
* blk_mq_{start,stop}_hw_queue(). |
|
*/ |
|
bool blk_mq_queue_stopped(struct request_queue *q) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) |
|
if (blk_mq_hctx_stopped(hctx)) |
|
return true; |
|
|
|
return false; |
|
} |
|
EXPORT_SYMBOL(blk_mq_queue_stopped); |
|
|
|
/* |
|
* This function is often used for pausing .queue_rq() by driver when |
|
* there isn't enough resource or some conditions aren't satisfied, and |
|
* BLK_STS_RESOURCE is usually returned. |
|
* |
|
* We do not guarantee that dispatch can be drained or blocked |
|
* after blk_mq_stop_hw_queue() returns. Please use |
|
* blk_mq_quiesce_queue() for that requirement. |
|
*/ |
|
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx) |
|
{ |
|
cancel_delayed_work(&hctx->run_work); |
|
|
|
set_bit(BLK_MQ_S_STOPPED, &hctx->state); |
|
} |
|
EXPORT_SYMBOL(blk_mq_stop_hw_queue); |
|
|
|
/* |
|
* This function is often used for pausing .queue_rq() by driver when |
|
* there isn't enough resource or some conditions aren't satisfied, and |
|
* BLK_STS_RESOURCE is usually returned. |
|
* |
|
* We do not guarantee that dispatch can be drained or blocked |
|
* after blk_mq_stop_hw_queues() returns. Please use |
|
* blk_mq_quiesce_queue() for that requirement. |
|
*/ |
|
void blk_mq_stop_hw_queues(struct request_queue *q) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) |
|
blk_mq_stop_hw_queue(hctx); |
|
} |
|
EXPORT_SYMBOL(blk_mq_stop_hw_queues); |
|
|
|
void blk_mq_start_hw_queue(struct blk_mq_hw_ctx *hctx) |
|
{ |
|
clear_bit(BLK_MQ_S_STOPPED, &hctx->state); |
|
|
|
blk_mq_run_hw_queue(hctx, false); |
|
} |
|
EXPORT_SYMBOL(blk_mq_start_hw_queue); |
|
|
|
void blk_mq_start_hw_queues(struct request_queue *q) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) |
|
blk_mq_start_hw_queue(hctx); |
|
} |
|
EXPORT_SYMBOL(blk_mq_start_hw_queues); |
|
|
|
void blk_mq_start_stopped_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) |
|
{ |
|
if (!blk_mq_hctx_stopped(hctx)) |
|
return; |
|
|
|
clear_bit(BLK_MQ_S_STOPPED, &hctx->state); |
|
blk_mq_run_hw_queue(hctx, async); |
|
} |
|
EXPORT_SYMBOL_GPL(blk_mq_start_stopped_hw_queue); |
|
|
|
void blk_mq_start_stopped_hw_queues(struct request_queue *q, bool async) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) |
|
blk_mq_start_stopped_hw_queue(hctx, async); |
|
} |
|
EXPORT_SYMBOL(blk_mq_start_stopped_hw_queues); |
|
|
|
static void blk_mq_run_work_fn(struct work_struct *work) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
|
|
hctx = container_of(work, struct blk_mq_hw_ctx, run_work.work); |
|
|
|
/* |
|
* If we are stopped, don't run the queue. |
|
*/ |
|
if (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 int plug_rq_cmp(void *priv, const struct list_head *a, |
|
const struct list_head *b) |
|
{ |
|
struct request *rqa = container_of(a, struct request, queuelist); |
|
struct request *rqb = container_of(b, struct request, queuelist); |
|
|
|
if (rqa->mq_ctx != rqb->mq_ctx) |
|
return rqa->mq_ctx > rqb->mq_ctx; |
|
if (rqa->mq_hctx != rqb->mq_hctx) |
|
return rqa->mq_hctx > rqb->mq_hctx; |
|
|
|
return blk_rq_pos(rqa) > blk_rq_pos(rqb); |
|
} |
|
|
|
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule) |
|
{ |
|
LIST_HEAD(list); |
|
|
|
if (list_empty(&plug->mq_list)) |
|
return; |
|
list_splice_init(&plug->mq_list, &list); |
|
|
|
if (plug->rq_count > 2 && plug->multiple_queues) |
|
list_sort(NULL, &list, plug_rq_cmp); |
|
|
|
plug->rq_count = 0; |
|
|
|
do { |
|
struct list_head rq_list; |
|
struct request *rq, *head_rq = list_entry_rq(list.next); |
|
struct list_head *pos = &head_rq->queuelist; /* skip first */ |
|
struct blk_mq_hw_ctx *this_hctx = head_rq->mq_hctx; |
|
struct blk_mq_ctx *this_ctx = head_rq->mq_ctx; |
|
unsigned int depth = 1; |
|
|
|
list_for_each_continue(pos, &list) { |
|
rq = list_entry_rq(pos); |
|
BUG_ON(!rq->q); |
|
if (rq->mq_hctx != this_hctx || rq->mq_ctx != this_ctx) |
|
break; |
|
depth++; |
|
} |
|
|
|
list_cut_before(&rq_list, &list, pos); |
|
trace_block_unplug(head_rq->q, depth, !from_schedule); |
|
blk_mq_sched_insert_requests(this_hctx, this_ctx, &rq_list, |
|
from_schedule); |
|
} while(!list_empty(&list)); |
|
} |
|
|
|
static void blk_mq_bio_to_request(struct request *rq, struct bio *bio, |
|
unsigned int nr_segs) |
|
{ |
|
int err; |
|
|
|
if (bio->bi_opf & REQ_RAHEAD) |
|
rq->cmd_flags |= REQ_FAILFAST_MASK; |
|
|
|
rq->__sector = bio->bi_iter.bi_sector; |
|
rq->write_hint = bio->bi_write_hint; |
|
blk_rq_bio_prep(rq, bio, nr_segs); |
|
|
|
/* This can't fail, since GFP_NOIO includes __GFP_DIRECT_RECLAIM. */ |
|
err = blk_crypto_rq_bio_prep(rq, bio, GFP_NOIO); |
|
WARN_ON_ONCE(err); |
|
|
|
blk_account_io_start(rq); |
|
} |
|
|
|
static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx, |
|
struct request *rq, |
|
blk_qc_t *cookie, bool last) |
|
{ |
|
struct request_queue *q = rq->q; |
|
struct blk_mq_queue_data bd = { |
|
.rq = rq, |
|
.last = last, |
|
}; |
|
blk_qc_t new_cookie; |
|
blk_status_t ret; |
|
|
|
new_cookie = request_to_qc_t(hctx, rq); |
|
|
|
/* |
|
* For OK queue, we are done. For error, caller may kill it. |
|
* Any other error (busy), just add it to our list as we |
|
* previously would have done. |
|
*/ |
|
ret = q->mq_ops->queue_rq(hctx, &bd); |
|
switch (ret) { |
|
case BLK_STS_OK: |
|
blk_mq_update_dispatch_busy(hctx, false); |
|
*cookie = new_cookie; |
|
break; |
|
case BLK_STS_RESOURCE: |
|
case BLK_STS_DEV_RESOURCE: |
|
blk_mq_update_dispatch_busy(hctx, true); |
|
__blk_mq_requeue_request(rq); |
|
break; |
|
default: |
|
blk_mq_update_dispatch_busy(hctx, false); |
|
*cookie = BLK_QC_T_NONE; |
|
break; |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, |
|
struct request *rq, |
|
blk_qc_t *cookie, |
|
bool bypass_insert, bool last) |
|
{ |
|
struct request_queue *q = rq->q; |
|
bool run_queue = true; |
|
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 (q->elevator && !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, cookie, 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. |
|
* @cookie: Request queue cookie. |
|
* |
|
* If the device has enough resources to accept a new request now, send the |
|
* request directly to device driver. Else, insert at hctx->dispatch queue, so |
|
* we can try send it another time in the future. Requests inserted at this |
|
* queue have higher priority. |
|
*/ |
|
static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, |
|
struct request *rq, blk_qc_t *cookie) |
|
{ |
|
blk_status_t ret; |
|
int srcu_idx; |
|
|
|
might_sleep_if(hctx->flags & BLK_MQ_F_BLOCKING); |
|
|
|
hctx_lock(hctx, &srcu_idx); |
|
|
|
ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true); |
|
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) |
|
blk_mq_request_bypass_insert(rq, false, true); |
|
else if (ret != BLK_STS_OK) |
|
blk_mq_end_request(rq, ret); |
|
|
|
hctx_unlock(hctx, srcu_idx); |
|
} |
|
|
|
blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last) |
|
{ |
|
blk_status_t ret; |
|
int srcu_idx; |
|
blk_qc_t unused_cookie; |
|
struct blk_mq_hw_ctx *hctx = rq->mq_hctx; |
|
|
|
hctx_lock(hctx, &srcu_idx); |
|
ret = __blk_mq_try_issue_directly(hctx, rq, &unused_cookie, true, last); |
|
hctx_unlock(hctx, srcu_idx); |
|
|
|
return ret; |
|
} |
|
|
|
void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx, |
|
struct list_head *list) |
|
{ |
|
int queued = 0; |
|
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) { |
|
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); |
|
errors++; |
|
} 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 void blk_add_rq_to_plug(struct blk_plug *plug, struct request *rq) |
|
{ |
|
list_add_tail(&rq->queuelist, &plug->mq_list); |
|
plug->rq_count++; |
|
if (!plug->multiple_queues && !list_is_singular(&plug->mq_list)) { |
|
struct request *tmp; |
|
|
|
tmp = list_first_entry(&plug->mq_list, struct request, |
|
queuelist); |
|
if (tmp->q != rq->q) |
|
plug->multiple_queues = true; |
|
} |
|
} |
|
|
|
/* |
|
* Allow 4x 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 * 4; |
|
return BLK_MAX_REQUEST_COUNT; |
|
} |
|
|
|
/** |
|
* 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. |
|
* |
|
* Returns: Request queue cookie. |
|
*/ |
|
blk_qc_t blk_mq_submit_bio(struct bio *bio) |
|
{ |
|
struct request_queue *q = bio->bi_bdev->bd_disk->queue; |
|
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 = { |
|
.q = q, |
|
}; |
|
struct request *rq; |
|
struct blk_plug *plug; |
|
struct request *same_queue_rq = NULL; |
|
unsigned int nr_segs; |
|
blk_qc_t cookie; |
|
blk_status_t ret; |
|
bool hipri; |
|
|
|
blk_queue_bounce(q, &bio); |
|
__blk_queue_split(&bio, &nr_segs); |
|
|
|
if (!bio_integrity_prep(bio)) |
|
goto queue_exit; |
|
|
|
if (!is_flush_fua && !blk_queue_nomerges(q) && |
|
blk_attempt_plug_merge(q, bio, nr_segs, &same_queue_rq)) |
|
goto queue_exit; |
|
|
|
if (blk_mq_sched_bio_merge(q, bio, nr_segs)) |
|
goto queue_exit; |
|
|
|
rq_qos_throttle(q, bio); |
|
|
|
hipri = bio->bi_opf & REQ_HIPRI; |
|
|
|
data.cmd_flags = bio->bi_opf; |
|
rq = __blk_mq_alloc_request(&data); |
|
if (unlikely(!rq)) { |
|
rq_qos_cleanup(q, bio); |
|
if (bio->bi_opf & REQ_NOWAIT) |
|
bio_wouldblock_error(bio); |
|
goto queue_exit; |
|
} |
|
|
|
trace_block_getrq(bio); |
|
|
|
rq_qos_track(q, rq, bio); |
|
|
|
cookie = request_to_qc_t(data.hctx, rq); |
|
|
|
blk_mq_bio_to_request(rq, bio, nr_segs); |
|
|
|
ret = blk_crypto_init_request(rq); |
|
if (ret != BLK_STS_OK) { |
|
bio->bi_status = ret; |
|
bio_endio(bio); |
|
blk_mq_free_request(rq); |
|
return BLK_QC_T_NONE; |
|
} |
|
|
|
plug = blk_mq_plug(q, bio); |
|
if (unlikely(is_flush_fua)) { |
|
/* Bypass scheduler for flush requests */ |
|
blk_insert_flush(rq); |
|
blk_mq_run_hw_queue(data.hctx, true); |
|
} else if (plug && (q->nr_hw_queues == 1 || |
|
blk_mq_is_sbitmap_shared(rq->mq_hctx->flags) || |
|
q->mq_ops->commit_rqs || !blk_queue_nonrot(q))) { |
|
/* |
|
* Use plugging if we have a ->commit_rqs() hook as well, as |
|
* we know the driver uses bd->last in a smart fashion. |
|
* |
|
* Use normal plugging if this disk is slow HDD, as sequential |
|
* IO may benefit a lot from plug merging. |
|
*/ |
|
unsigned int request_count = plug->rq_count; |
|
struct request *last = NULL; |
|
|
|
if (!request_count) |
|
trace_block_plug(q); |
|
else |
|
last = list_entry_rq(plug->mq_list.prev); |
|
|
|
if (request_count >= blk_plug_max_rq_count(plug) || (last && |
|
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) { |
|
blk_flush_plug_list(plug, false); |
|
trace_block_plug(q); |
|
} |
|
|
|
blk_add_rq_to_plug(plug, rq); |
|
} else if (q->elevator) { |
|
/* Insert the request at the IO scheduler queue */ |
|
blk_mq_sched_insert_request(rq, false, true, true); |
|
} else if (plug && !blk_queue_nomerges(q)) { |
|
/* |
|
* We do limited plugging. If the bio can be merged, do that. |
|
* Otherwise the existing request in the plug list will be |
|
* issued. So the plug list will have one request at most |
|
* The plug list might get flushed before this. If that happens, |
|
* the plug list is empty, and same_queue_rq is invalid. |
|
*/ |
|
if (list_empty(&plug->mq_list)) |
|
same_queue_rq = NULL; |
|
if (same_queue_rq) { |
|
list_del_init(&same_queue_rq->queuelist); |
|
plug->rq_count--; |
|
} |
|
blk_add_rq_to_plug(plug, rq); |
|
trace_block_plug(q); |
|
|
|
if (same_queue_rq) { |
|
data.hctx = same_queue_rq->mq_hctx; |
|
trace_block_unplug(q, 1, true); |
|
blk_mq_try_issue_directly(data.hctx, same_queue_rq, |
|
&cookie); |
|
} |
|
} else if ((q->nr_hw_queues > 1 && is_sync) || |
|
!data.hctx->dispatch_busy) { |
|
/* |
|
* There is no scheduler and we can try to send directly |
|
* to the hardware. |
|
*/ |
|
blk_mq_try_issue_directly(data.hctx, rq, &cookie); |
|
} else { |
|
/* Default case. */ |
|
blk_mq_sched_insert_request(rq, false, true, true); |
|
} |
|
|
|
if (!hipri) |
|
return BLK_QC_T_NONE; |
|
return cookie; |
|
queue_exit: |
|
blk_queue_exit(q); |
|
return BLK_QC_T_NONE; |
|
} |
|
|
|
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_tag_set *set, |
|
struct blk_mq_tags *tags, unsigned int hctx_idx) |
|
{ |
|
struct blk_mq_tags *drv_tags = set->tags[hctx_idx]; |
|
struct page *page; |
|
unsigned long flags; |
|
|
|
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 < set->queue_depth; 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(refcount_read(&rq->ref) != 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 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; |
|
} |
|
} |
|
|
|
blk_mq_clear_rq_mapping(set, tags, hctx_idx); |
|
|
|
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, unsigned int flags) |
|
{ |
|
kfree(tags->rqs); |
|
tags->rqs = NULL; |
|
kfree(tags->static_rqs); |
|
tags->static_rqs = NULL; |
|
|
|
blk_mq_free_tags(tags, flags); |
|
} |
|
|
|
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, |
|
unsigned int flags) |
|
{ |
|
struct blk_mq_tags *tags; |
|
int node; |
|
|
|
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx); |
|
if (node == NUMA_NO_NODE) |
|
node = set->numa_node; |
|
|
|
tags = blk_mq_init_tags(nr_tags, reserved_tags, node, 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, flags); |
|
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, flags); |
|
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; |
|
} |
|
|
|
int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags, |
|
unsigned int hctx_idx, unsigned int depth) |
|
{ |
|
unsigned int i, j, entries_per_page, max_order = 4; |
|
size_t rq_size, left; |
|
int node; |
|
|
|
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], hctx_idx); |
|
if (node == NUMA_NO_NODE) |
|
node = set->numa_node; |
|
|
|
INIT_LIST_HEAD(&tags->page_list); |
|
|
|
/* |
|
* rq_size is the size of the request plus driver payload, rounded |
|
* to the cacheline size |
|
*/ |
|
rq_size = round_up(sizeof(struct request) + set->cmd_size, |
|
cache_line_size()); |
|
left = rq_size * depth; |
|
|
|
for (i = 0; i < depth; ) { |
|
int this_order = max_order; |
|
struct page *page; |
|
int to_do; |
|
void *p; |
|
|
|
while (this_order && left < order_to_size(this_order - 1)) |
|
this_order--; |
|
|
|
do { |
|
page = alloc_pages_node(node, |
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO, |
|
this_order); |
|
if (page) |
|
break; |
|
if (!this_order--) |
|
break; |
|
if (order_to_size(this_order) < rq_size) |
|
break; |
|
} while (1); |
|
|
|
if (!page) |
|
goto fail; |
|
|
|
page->private = this_order; |
|
list_add_tail(&page->lru, &tags->page_list); |
|
|
|
p = page_address(page); |
|
/* |
|
* Allow kmemleak to scan these pages as they contain pointers |
|
* to additional allocations like via ops->init_request(). |
|
*/ |
|
kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO); |
|
entries_per_page = order_to_size(this_order) / rq_size; |
|
to_do = min(entries_per_page, depth - i); |
|
left -= to_do * rq_size; |
|
for (j = 0; j < to_do; j++) { |
|
struct request *rq = p; |
|
|
|
tags->static_rqs[i] = rq; |
|
if (blk_mq_init_request(set, rq, hctx_idx, node)) { |
|
tags->static_rqs[i] = NULL; |
|
goto fail; |
|
} |
|
|
|
p += rq_size; |
|
i++; |
|
} |
|
} |
|
return 0; |
|
|
|
fail: |
|
blk_mq_free_rqs(set, tags, hctx_idx); |
|
return -ENOMEM; |
|
} |
|
|
|
struct rq_iter_data { |
|
struct blk_mq_hw_ctx *hctx; |
|
bool has_rq; |
|
}; |
|
|
|
static bool blk_mq_has_request(struct request *rq, void *data, bool reserved) |
|
{ |
|
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_next_and(-1, 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(refcount_read(&flush_rq->ref) != 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); |
|
|
|
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); |
|
|
|
spin_lock(&q->unused_hctx_lock); |
|
list_add(&hctx->hctx_list, &q->unused_hctx_list); |
|
spin_unlock(&q->unused_hctx_lock); |
|
} |
|
|
|
static void blk_mq_exit_hw_queues(struct request_queue *q, |
|
struct blk_mq_tag_set *set, int nr_queue) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
unsigned int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) { |
|
if (i == nr_queue) |
|
break; |
|
blk_mq_debugfs_unregister_hctx(hctx); |
|
blk_mq_exit_hctx(q, set, hctx, i); |
|
} |
|
} |
|
|
|
static int blk_mq_hw_ctx_size(struct blk_mq_tag_set *tag_set) |
|
{ |
|
int hw_ctx_size = sizeof(struct blk_mq_hw_ctx); |
|
|
|
BUILD_BUG_ON(ALIGN(offsetof(struct blk_mq_hw_ctx, srcu), |
|
__alignof__(struct blk_mq_hw_ctx)) != |
|
sizeof(struct blk_mq_hw_ctx)); |
|
|
|
if (tag_set->flags & BLK_MQ_F_BLOCKING) |
|
hw_ctx_size += sizeof(struct srcu_struct); |
|
|
|
return hw_ctx_size; |
|
} |
|
|
|
static int blk_mq_init_hctx(struct request_queue *q, |
|
struct blk_mq_tag_set *set, |
|
struct blk_mq_hw_ctx *hctx, unsigned hctx_idx) |
|
{ |
|
hctx->queue_num = hctx_idx; |
|
|
|
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; |
|
return 0; |
|
|
|
exit_hctx: |
|
if (set->ops->exit_hctx) |
|
set->ops->exit_hctx(hctx, hctx_idx); |
|
unregister_cpu_notifier: |
|
blk_mq_remove_cpuhp(hctx); |
|
return -1; |
|
} |
|
|
|
static struct blk_mq_hw_ctx * |
|
blk_mq_alloc_hctx(struct request_queue *q, struct blk_mq_tag_set *set, |
|
int node) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY; |
|
|
|
hctx = kzalloc_node(blk_mq_hw_ctx_size(set), gfp, node); |
|
if (!hctx) |
|
goto fail_alloc_hctx; |
|
|
|
if (!zalloc_cpumask_var_node(&hctx->cpumask, gfp, node)) |
|
goto free_hctx; |
|
|
|
atomic_set(&hctx->nr_active, 0); |
|
if (node == NUMA_NO_NODE) |
|
node = set->numa_node; |
|
hctx->numa_node = node; |
|
|
|
INIT_DELAYED_WORK(&hctx->run_work, blk_mq_run_work_fn); |
|
spin_lock_init(&hctx->lock); |
|
INIT_LIST_HEAD(&hctx->dispatch); |
|
hctx->queue = q; |
|
hctx->flags = set->flags & ~BLK_MQ_F_TAG_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; |
|
|
|
if (hctx->flags & BLK_MQ_F_BLOCKING) |
|
init_srcu_struct(hctx->srcu); |
|
blk_mq_hctx_kobj_init(hctx); |
|
|
|
return hctx; |
|
|
|
free_bitmap: |
|
sbitmap_free(&hctx->ctx_map); |
|
free_ctxs: |
|
kfree(hctx->ctxs); |
|
free_cpumask: |
|
free_cpumask_var(hctx->cpumask); |
|
free_hctx: |
|
kfree(hctx); |
|
fail_alloc_hctx: |
|
return NULL; |
|
} |
|
|
|
static void blk_mq_init_cpu_queues(struct request_queue *q, |
|
unsigned int nr_hw_queues) |
|
{ |
|
struct blk_mq_tag_set *set = q->tag_set; |
|
unsigned int i, j; |
|
|
|
for_each_possible_cpu(i) { |
|
struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i); |
|
struct blk_mq_hw_ctx *hctx; |
|
int k; |
|
|
|
__ctx->cpu = i; |
|
spin_lock_init(&__ctx->lock); |
|
for (k = HCTX_TYPE_DEFAULT; k < HCTX_MAX_TYPES; k++) |
|
INIT_LIST_HEAD(&__ctx->rq_lists[k]); |
|
|
|
__ctx->queue = q; |
|
|
|
/* |
|
* Set local node, IFF we have more than one hw queue. If |
|
* not, we remain on the home node of the device |
|
*/ |
|
for (j = 0; j < set->nr_maps; j++) { |
|
hctx = blk_mq_map_queue_type(q, j, i); |
|
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE) |
|
hctx->numa_node = cpu_to_node(i); |
|
} |
|
} |
|
} |
|
|
|
static bool __blk_mq_alloc_map_and_request(struct blk_mq_tag_set *set, |
|
int hctx_idx) |
|
{ |
|
unsigned int flags = set->flags; |
|
int ret = 0; |
|
|
|
set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx, |
|
set->queue_depth, set->reserved_tags, flags); |
|
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], flags); |
|
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) |
|
{ |
|
unsigned int flags = set->flags; |
|
|
|
if (set->tags && set->tags[hctx_idx]) { |
|
blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx); |
|
blk_mq_free_rq_map(set->tags[hctx_idx], flags); |
|
set->tags[hctx_idx] = NULL; |
|
} |
|
} |
|
|
|
static void blk_mq_map_swqueue(struct request_queue *q) |
|
{ |
|
unsigned int i, j, hctx_idx; |
|
struct blk_mq_hw_ctx *hctx; |
|
struct blk_mq_ctx *ctx; |
|
struct blk_mq_tag_set *set = q->tag_set; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) { |
|
cpumask_clear(hctx->cpumask); |
|
hctx->nr_ctx = 0; |
|
hctx->dispatch_from = NULL; |
|
} |
|
|
|
/* |
|
* Map software to hardware queues. |
|
* |
|
* If the cpu isn't present, the cpu is mapped to first hctx. |
|
*/ |
|
for_each_possible_cpu(i) { |
|
|
|
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_request(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 && set->tags[i]) |
|
blk_mq_free_map_and_requests(set, i); |
|
|
|
hctx->tags = NULL; |
|
continue; |
|
} |
|
|
|
hctx->tags = set->tags[i]; |
|
WARN_ON(!hctx->tags); |
|
|
|
/* |
|
* Set the map size to the number of mapped software queues. |
|
* This is more accurate and more efficient than looping |
|
* over all possibly mapped software queues. |
|
*/ |
|
sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx); |
|
|
|
/* |
|
* Initialize batch roundrobin counts |
|
*/ |
|
hctx->next_cpu = blk_mq_first_mapped_cpu(hctx); |
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH; |
|
} |
|
} |
|
|
|
/* |
|
* Caller needs to ensure that we're either frozen/quiesced, or that |
|
* the queue isn't live yet. |
|
*/ |
|
static void queue_set_hctx_shared(struct request_queue *q, bool shared) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) { |
|
if (shared) { |
|
hctx->flags |= BLK_MQ_F_TAG_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; |
|
int i; |
|
|
|
queue_for_each_hw_ctx(q, hctx, i) |
|
WARN_ON_ONCE(hctx && list_empty(&hctx->hctx_list)); |
|
|
|
/* all hctx are in .unused_hctx_list now */ |
|
list_for_each_entry_safe(hctx, next, &q->unused_hctx_list, hctx_list) { |
|
list_del_init(&hctx->hctx_list); |
|
kobject_put(&hctx->kobj); |
|
} |
|
|
|
kfree(q->queue_hw_ctx); |
|
|
|
/* |
|
* release .mq_kobj and sw queue's kobject now because |
|
* both share lifetime with request queue. |
|
*/ |
|
blk_mq_sysfs_deinit(q); |
|
} |
|
|
|
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); |
|
if (!q) |
|
return ERR_PTR(-ENOMEM); |
|
q->queuedata = queuedata; |
|
ret = blk_mq_init_allocated_queue(set, q); |
|
if (ret) { |
|
blk_cleanup_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); |
|
|
|
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_cleanup_queue(q); |
|
return ERR_PTR(-ENOMEM); |
|
} |
|
return disk; |
|
} |
|
EXPORT_SYMBOL(__blk_mq_alloc_disk); |
|
|
|
static struct blk_mq_hw_ctx *blk_mq_alloc_and_init_hctx( |
|
struct blk_mq_tag_set *set, struct request_queue *q, |
|
int hctx_idx, int node) |
|
{ |
|
struct blk_mq_hw_ctx *hctx = NULL, *tmp; |
|
|
|
/* reuse dead hctx first */ |
|
spin_lock(&q->unused_hctx_lock); |
|
list_for_each_entry(tmp, &q->unused_hctx_list, hctx_list) { |
|
if (tmp->numa_node == node) { |
|
hctx = tmp; |
|
break; |
|
} |
|
} |
|
if (hctx) |
|
list_del_init(&hctx->hctx_list); |
|
spin_unlock(&q->unused_hctx_lock); |
|
|
|
if (!hctx) |
|
hctx = blk_mq_alloc_hctx(q, set, node); |
|
if (!hctx) |
|
goto fail; |
|
|
|
if (blk_mq_init_hctx(q, set, hctx, hctx_idx)) |
|
goto free_hctx; |
|
|
|
return hctx; |
|
|
|
free_hctx: |
|
kobject_put(&hctx->kobj); |
|
fail: |
|
return NULL; |
|
} |
|
|
|
static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set, |
|
struct request_queue *q) |
|
{ |
|
int i, j, end; |
|
struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx; |
|
|
|
if (q->nr_hw_queues < set->nr_hw_queues) { |
|
struct blk_mq_hw_ctx **new_hctxs; |
|
|
|
new_hctxs = kcalloc_node(set->nr_hw_queues, |
|
sizeof(*new_hctxs), GFP_KERNEL, |
|
set->numa_node); |
|
if (!new_hctxs) |
|
return; |
|
if (hctxs) |
|
memcpy(new_hctxs, hctxs, q->nr_hw_queues * |
|
sizeof(*hctxs)); |
|
q->queue_hw_ctx = new_hctxs; |
|
kfree(hctxs); |
|
hctxs = new_hctxs; |
|
} |
|
|
|
/* protect against switching io scheduler */ |
|
mutex_lock(&q->sysfs_lock); |
|
for (i = 0; i < set->nr_hw_queues; i++) { |
|
int node; |
|
struct blk_mq_hw_ctx *hctx; |
|
|
|
node = blk_mq_hw_queue_to_node(&set->map[HCTX_TYPE_DEFAULT], i); |
|
/* |
|
* If the hw queue has been mapped to another numa node, |
|
* we need to realloc the hctx. If allocation fails, fallback |
|
* to use the previous one. |
|
*/ |
|
if (hctxs[i] && (hctxs[i]->numa_node == node)) |
|
continue; |
|
|
|
hctx = blk_mq_alloc_and_init_hctx(set, q, i, node); |
|
if (hctx) { |
|
if (hctxs[i]) |
|
blk_mq_exit_hctx(q, set, hctxs[i], i); |
|
hctxs[i] = hctx; |
|
} else { |
|
if (hctxs[i]) |
|
pr_warn("Allocate new hctx on node %d fails,\ |
|
fallback to previous one on node %d\n", |
|
node, hctxs[i]->numa_node); |
|
else |
|
break; |
|
} |
|
} |
|
/* |
|
* Increasing nr_hw_queues fails. Free the newly allocated |
|
* hctxs and keep the previous q->nr_hw_queues. |
|
*/ |
|
if (i != set->nr_hw_queues) { |
|
j = q->nr_hw_queues; |
|
end = i; |
|
} else { |
|
j = i; |
|
end = q->nr_hw_queues; |
|
q->nr_hw_queues = set->nr_hw_queues; |
|
} |
|
|
|
for (; j < end; j++) { |
|
struct blk_mq_hw_ctx *hctx = hctxs[j]; |
|
|
|
if (hctx) { |
|
if (hctx->tags) |
|
blk_mq_free_map_and_requests(set, j); |
|
blk_mq_exit_hctx(q, set, hctx, j); |
|
hctxs[j] = NULL; |
|
} |
|
} |
|
mutex_unlock(&q->sysfs_lock); |
|
} |
|
|
|
int 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; |
|
|
|
if (blk_mq_alloc_ctxs(q)) |
|
goto err_poll; |
|
|
|
/* init q->mq_kobj and sw queues' kobjects */ |
|
blk_mq_sysfs_init(q); |
|
|
|
INIT_LIST_HEAD(&q->unused_hctx_list); |
|
spin_lock_init(&q->unused_hctx_lock); |
|
|
|
blk_mq_realloc_hw_ctxs(set, q); |
|
if (!q->nr_hw_queues) |
|
goto err_hctxs; |
|
|
|
INIT_WORK(&q->timeout_work, blk_mq_timeout_work); |
|
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); |
|
|
|
q->tag_set = set; |
|
|
|
q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT; |
|
if (set->nr_maps > HCTX_TYPE_POLL && |
|
set->map[HCTX_TYPE_POLL].nr_queues) |
|
blk_queue_flag_set(QUEUE_FLAG_POLL, q); |
|
|
|
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: |
|
kfree(q->queue_hw_ctx); |
|
q->nr_hw_queues = 0; |
|
blk_mq_sysfs_deinit(q); |
|
err_poll: |
|
blk_stat_free_callback(q->poll_cb); |
|
q->poll_cb = NULL; |
|
err_exit: |
|
q->mq_ops = NULL; |
|
return -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; |
|
|
|
for (i = 0; i < set->nr_hw_queues; i++) { |
|
if (!__blk_mq_alloc_map_and_request(set, i)) |
|
goto out_unwind; |
|
cond_resched(); |
|
} |
|
|
|
return 0; |
|
|
|
out_unwind: |
|
while (--i >= 0) |
|
blk_mq_free_map_and_requests(set, 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_map_and_requests(struct blk_mq_tag_set *set) |
|
{ |
|
unsigned int depth; |
|
int err; |
|
|
|
depth = set->queue_depth; |
|
do { |
|
err = __blk_mq_alloc_rq_maps(set); |
|
if (!err) |
|
break; |
|
|
|
set->queue_depth >>= 1; |
|
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) { |
|
err = -ENOMEM; |
|
break; |
|
} |
|
} while (set->queue_depth); |
|
|
|
if (!set->queue_depth || err) { |
|
pr_err("blk-mq: failed to allocate request map\n"); |
|
return -ENOMEM; |
|
} |
|
|
|
if (depth != set->queue_depth) |
|
pr_info("blk-mq: reduced tag depth (%u -> %u)\n", |
|
depth, set->queue_depth); |
|
|
|
return 0; |
|
} |
|
|
|
static int blk_mq_update_queue_map(struct blk_mq_tag_set *set) |
|
{ |
|
/* |
|
* blk_mq_map_queues() and multiple .map_queues() implementations |
|
* expect that set->map[HCTX_TYPE_DEFAULT].nr_queues is set to the |
|
* number of hardware queues. |
|
*/ |
|
if (set->nr_maps == 1) |
|
set->map[HCTX_TYPE_DEFAULT].nr_queues = set->nr_hw_queues; |
|
|
|
if (set->ops->map_queues && !is_kdump_kernel()) { |
|
int i; |
|
|
|
/* |
|
* transport .map_queues is usually done in the following |
|
* way: |
|
* |
|
* for (queue = 0; queue < set->nr_hw_queues; queue++) { |
|
* mask = get_cpu_mask(queue) |
|
* for_each_cpu(cpu, mask) |
|
* set->map[x].mq_map[cpu] = queue; |
|
* } |
|
* |
|
* When we need to remap, the table has to be cleared for |
|
* killing stale mapping since one CPU may not be mapped |
|
* to any hw queue. |
|
*/ |
|
for (i = 0; i < set->nr_maps; i++) |
|
blk_mq_clear_mq_map(&set->map[i]); |
|
|
|
return set->ops->map_queues(set); |
|
} else { |
|
BUG_ON(set->nr_maps > 1); |
|
return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); |
|
} |
|
} |
|
|
|
static int blk_mq_realloc_tag_set_tags(struct blk_mq_tag_set *set, |
|
int cur_nr_hw_queues, int new_nr_hw_queues) |
|
{ |
|
struct blk_mq_tags **new_tags; |
|
|
|
if (cur_nr_hw_queues >= new_nr_hw_queues) |
|
return 0; |
|
|
|
new_tags = kcalloc_node(new_nr_hw_queues, sizeof(struct blk_mq_tags *), |
|
GFP_KERNEL, set->numa_node); |
|
if (!new_tags) |
|
return -ENOMEM; |
|
|
|
if (set->tags) |
|
memcpy(new_tags, set->tags, cur_nr_hw_queues * |
|
sizeof(*set->tags)); |
|
kfree(set->tags); |
|
set->tags = new_tags; |
|
set->nr_hw_queues = new_nr_hw_queues; |
|
|
|
return 0; |
|
} |
|
|
|
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; |
|
} |
|
|
|
ret = blk_mq_update_queue_map(set); |
|
if (ret) |
|
goto out_free_mq_map; |
|
|
|
ret = blk_mq_alloc_map_and_requests(set); |
|
if (ret) |
|
goto out_free_mq_map; |
|
|
|
if (blk_mq_is_sbitmap_shared(set->flags)) { |
|
atomic_set(&set->active_queues_shared_sbitmap, 0); |
|
|
|
if (blk_mq_init_shared_sbitmap(set)) { |
|
ret = -ENOMEM; |
|
goto out_free_mq_rq_maps; |
|
} |
|
} |
|
|
|
mutex_init(&set->tag_list_lock); |
|
INIT_LIST_HEAD(&set->tag_list); |
|
|
|
return 0; |
|
|
|
out_free_mq_rq_maps: |
|
for (i = 0; i < set->nr_hw_queues; i++) |
|
blk_mq_free_map_and_requests(set, i); |
|
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_requests(set, i); |
|
|
|
if (blk_mq_is_sbitmap_shared(set->flags)) |
|
blk_mq_exit_shared_sbitmap(set); |
|
|
|
for (j = 0; j < set->nr_maps; j++) { |
|
kfree(set->map[j].mq_map); |
|
set->map[j].mq_map = NULL; |
|
} |
|
|
|
kfree(set->tags); |
|
set->tags = NULL; |
|
} |
|
EXPORT_SYMBOL(blk_mq_free_tag_set); |
|
|
|
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) |
|
{ |
|
struct blk_mq_tag_set *set = q->tag_set; |
|
struct blk_mq_hw_ctx *hctx; |
|
int i, ret; |
|
|
|
if (!set) |
|
return -EINVAL; |
|
|
|
if (q->nr_requests == nr) |
|
return 0; |
|
|
|
blk_mq_freeze_queue(q); |
|
blk_mq_quiesce_queue(q); |
|
|
|
ret = 0; |
|
queue_for_each_hw_ctx(q, hctx, i) { |
|
if (!hctx->tags) |
|
continue; |
|
/* |
|
* If we're using an MQ scheduler, just update the scheduler |
|
* queue depth. This is similar to what the old code would do. |
|
*/ |
|
if (!hctx->sched_tags) { |
|
ret = blk_mq_tag_update_depth(hctx, &hctx->tags, nr, |
|
false); |
|
if (!ret && blk_mq_is_sbitmap_shared(set->flags)) |
|
blk_mq_tag_resize_shared_sbitmap(set, nr); |
|
} else { |
|
ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags, |
|
nr, true); |
|
if (blk_mq_is_sbitmap_shared(set->flags)) { |
|
hctx->sched_tags->bitmap_tags = |
|
&q->sched_bitmap_tags; |
|
hctx->sched_tags->breserved_tags = |
|
&q->sched_breserved_tags; |
|
} |
|
} |
|
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 (q->elevator && blk_mq_is_sbitmap_shared(set->flags)) |
|
sbitmap_queue_resize(&q->sched_bitmap_tags, |
|
nr - set->reserved_tags); |
|
} |
|
|
|
blk_mq_unquiesce_queue(q); |
|
blk_mq_unfreeze_queue(q); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* request_queue and elevator_type pair. |
|
* It is just used by __blk_mq_update_nr_hw_queues to cache |
|
* the elevator_type associated with a request_queue. |
|
*/ |
|
struct blk_mq_qe_pair { |
|
struct list_head node; |
|
struct request_queue *q; |
|
struct elevator_type *type; |
|
}; |
|
|
|
/* |
|
* Cache the elevator_type in qe pair list and switch the |
|
* io scheduler to 'none' |
|
*/ |
|
static bool blk_mq_elv_switch_none(struct list_head *head, |
|
struct request_queue *q) |
|
{ |
|
struct blk_mq_qe_pair *qe; |
|
|
|
if (!q->elevator) |
|
return true; |
|
|
|
qe = kmalloc(sizeof(*qe), GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY); |
|
if (!qe) |
|
return false; |
|
|
|
INIT_LIST_HEAD(&qe->node); |
|
qe->q = q; |
|
qe->type = q->elevator->type; |
|
list_add(&qe->node, head); |
|
|
|
mutex_lock(&q->sysfs_lock); |
|
/* |
|
* After elevator_switch_mq, the previous elevator_queue will be |
|
* released by elevator_release. The reference of the io scheduler |
|
* module get by elevator_get will also be put. So we need to get |
|
* a reference of the io scheduler module here to prevent it to be |
|
* removed. |
|
*/ |
|
__module_get(qe->type->elevator_owner); |
|
elevator_switch_mq(q, NULL); |
|
mutex_unlock(&q->sysfs_lock); |
|
|
|
return true; |
|
} |
|
|
|
static void blk_mq_elv_switch_back(struct list_head *head, |
|
struct request_queue *q) |
|
{ |
|
struct blk_mq_qe_pair *qe; |
|
struct elevator_type *t = NULL; |
|
|
|
list_for_each_entry(qe, head, node) |
|
if (qe->q == q) { |
|
t = qe->type; |
|
break; |
|
} |
|
|
|
if (!t) |
|
return; |
|
|
|
list_del(&qe->node); |
|
kfree(qe); |
|
|
|
mutex_lock(&q->sysfs_lock); |
|
elevator_switch_mq(q, t); |
|
mutex_unlock(&q->sysfs_lock); |
|
} |
|
|
|
static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, |
|
int nr_hw_queues) |
|
{ |
|
struct request_queue *q; |
|
LIST_HEAD(head); |
|
int prev_nr_hw_queues; |
|
|
|
lockdep_assert_held(&set->tag_list_lock); |
|
|
|
if (set->nr_maps == 1 && nr_hw_queues > nr_cpu_ids) |
|
nr_hw_queues = nr_cpu_ids; |
|
if (nr_hw_queues < 1) |
|
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(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); |
|
if (q->nr_hw_queues != set->nr_hw_queues) { |
|
pr_warn("Increasing nr_hw_queues to %d fails, fallback to %d\n", |
|
nr_hw_queues, prev_nr_hw_queues); |
|
set->nr_hw_queues = prev_nr_hw_queues; |
|
blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]); |
|
goto fallback; |
|
} |
|
blk_mq_map_swqueue(q); |
|
} |
|
|
|
reregister: |
|
list_for_each_entry(q, &set->tag_list, tag_set_list) { |
|
blk_mq_sysfs_register(q); |
|
blk_mq_debugfs_register_hctxs(q); |
|
} |
|
|
|
switch_back: |
|
list_for_each_entry(q, &set->tag_list, tag_set_list) |
|
blk_mq_elv_switch_back(&head, q); |
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) |
|
blk_mq_unfreeze_queue(q); |
|
} |
|
|
|
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) |
|
{ |
|
mutex_lock(&set->tag_list_lock); |
|
__blk_mq_update_nr_hw_queues(set, nr_hw_queues); |
|
mutex_unlock(&set->tag_list_lock); |
|
} |
|
EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); |
|
|
|
/* Enable polling stats and return whether they were already enabled. */ |
|
static bool blk_poll_stats_enable(struct request_queue *q) |
|
{ |
|
if (test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || |
|
blk_queue_flag_test_and_set(QUEUE_FLAG_POLL_STATS, q)) |
|
return true; |
|
blk_stat_add_callback(q, q->poll_cb); |
|
return false; |
|
} |
|
|
|
static void blk_mq_poll_stats_start(struct request_queue *q) |
|
{ |
|
/* |
|
* We don't arm the callback if polling stats are not enabled or the |
|
* callback is already active. |
|
*/ |
|
if (!test_bit(QUEUE_FLAG_POLL_STATS, &q->queue_flags) || |
|
blk_stat_is_active(q->poll_cb)) |
|
return; |
|
|
|
blk_stat_activate_msecs(q->poll_cb, 100); |
|
} |
|
|
|
static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb) |
|
{ |
|
struct request_queue *q = cb->data; |
|
int bucket; |
|
|
|
for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS; bucket++) { |
|
if (cb->stat[bucket].nr_samples) |
|
q->poll_stat[bucket] = cb->stat[bucket]; |
|
} |
|
} |
|
|
|
static unsigned long blk_mq_poll_nsecs(struct request_queue *q, |
|
struct request *rq) |
|
{ |
|
unsigned long ret = 0; |
|
int bucket; |
|
|
|
/* |
|
* If stats collection isn't on, don't sleep but turn it on for |
|
* future users |
|
*/ |
|
if (!blk_poll_stats_enable(q)) |
|
return 0; |
|
|
|
/* |
|
* As an optimistic guess, use half of the mean service time |
|
* for this type of request. We can (and should) make this smarter. |
|
* For instance, if the completion latencies are tight, we can |
|
* get closer than just half the mean. This is especially |
|
* important on devices where the completion latencies are longer |
|
* than ~10 usec. We do use the stats for the relevant IO size |
|
* if available which does lead to better estimates. |
|
*/ |
|
bucket = blk_mq_poll_stats_bkt(rq); |
|
if (bucket < 0) |
|
return ret; |
|
|
|
if (q->poll_stat[bucket].nr_samples) |
|
ret = (q->poll_stat[bucket].mean + 1) / 2; |
|
|
|
return ret; |
|
} |
|
|
|
static bool blk_mq_poll_hybrid_sleep(struct request_queue *q, |
|
struct request *rq) |
|
{ |
|
struct hrtimer_sleeper hs; |
|
enum hrtimer_mode mode; |
|
unsigned int nsecs; |
|
ktime_t kt; |
|
|
|
if (rq->rq_flags & RQF_MQ_POLL_SLEPT) |
|
return false; |
|
|
|
/* |
|
* If we get here, hybrid polling is enabled. Hence poll_nsec can be: |
|
* |
|
* 0: use half of prev avg |
|
* >0: use this specific value |
|
*/ |
|
if (q->poll_nsec > 0) |
|
nsecs = q->poll_nsec; |
|
else |
|
nsecs = blk_mq_poll_nsecs(q, rq); |
|
|
|
if (!nsecs) |
|
return false; |
|
|
|
rq->rq_flags |= RQF_MQ_POLL_SLEPT; |
|
|
|
/* |
|
* This will be replaced with the stats tracking code, using |
|
* 'avg_completion_time / 2' as the pre-sleep target. |
|
*/ |
|
kt = nsecs; |
|
|
|
mode = HRTIMER_MODE_REL; |
|
hrtimer_init_sleeper_on_stack(&hs, CLOCK_MONOTONIC, mode); |
|
hrtimer_set_expires(&hs.timer, kt); |
|
|
|
do { |
|
if (blk_mq_rq_state(rq) == MQ_RQ_COMPLETE) |
|
break; |
|
set_current_state(TASK_UNINTERRUPTIBLE); |
|
hrtimer_sleeper_start_expires(&hs, mode); |
|
if (hs.task) |
|
io_schedule(); |
|
hrtimer_cancel(&hs.timer); |
|
mode = HRTIMER_MODE_ABS; |
|
} while (hs.task && !signal_pending(current)); |
|
|
|
__set_current_state(TASK_RUNNING); |
|
destroy_hrtimer_on_stack(&hs.timer); |
|
return true; |
|
} |
|
|
|
static bool blk_mq_poll_hybrid(struct request_queue *q, |
|
struct blk_mq_hw_ctx *hctx, blk_qc_t cookie) |
|
{ |
|
struct request *rq; |
|
|
|
if (q->poll_nsec == BLK_MQ_POLL_CLASSIC) |
|
return false; |
|
|
|
if (!blk_qc_t_is_internal(cookie)) |
|
rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie)); |
|
else { |
|
rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie)); |
|
/* |
|
* With scheduling, if the request has completed, we'll |
|
* get a NULL return here, as we clear the sched tag when |
|
* that happens. The request still remains valid, like always, |
|
* so we should be safe with just the NULL check. |
|
*/ |
|
if (!rq) |
|
return false; |
|
} |
|
|
|
return blk_mq_poll_hybrid_sleep(q, rq); |
|
} |
|
|
|
/** |
|
* blk_poll - poll for IO completions |
|
* @q: the queue |
|
* @cookie: cookie passed back at IO submission time |
|
* @spin: whether to spin for completions |
|
* |
|
* Description: |
|
* Poll for completions on the passed in queue. Returns number of |
|
* completed entries found. If @spin is true, then blk_poll will continue |
|
* looping until at least one completion is found, unless the task is |
|
* otherwise marked running (or we need to reschedule). |
|
*/ |
|
int blk_poll(struct request_queue *q, blk_qc_t cookie, bool spin) |
|
{ |
|
struct blk_mq_hw_ctx *hctx; |
|
unsigned int state; |
|
|
|
if (!blk_qc_t_valid(cookie) || |
|
!test_bit(QUEUE_FLAG_POLL, &q->queue_flags)) |
|
return 0; |
|
|
|
if (current->plug) |
|
blk_flush_plug_list(current->plug, false); |
|
|
|
hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)]; |
|
|
|
/* |
|
* If we sleep, have the caller restart the poll loop to reset |
|
* the state. Like for the other success return cases, the |
|
* caller is responsible for checking if the IO completed. If |
|
* the IO isn't complete, we'll get called again and will go |
|
* straight to the busy poll loop. If specified not to spin, |
|
* we also should not sleep. |
|
*/ |
|
if (spin && blk_mq_poll_hybrid(q, hctx, cookie)) |
|
return 1; |
|
|
|
hctx->poll_considered++; |
|
|
|
state = get_current_state(); |
|
do { |
|
int ret; |
|
|
|
hctx->poll_invoked++; |
|
|
|
ret = q->mq_ops->poll(hctx); |
|
if (ret > 0) { |
|
hctx->poll_success++; |
|
__set_current_state(TASK_RUNNING); |
|
return ret; |
|
} |
|
|
|
if (signal_pending_state(state, current)) |
|
__set_current_state(TASK_RUNNING); |
|
|
|
if (task_is_running(current)) |
|
return 1; |
|
if (ret < 0 || !spin) |
|
break; |
|
cpu_relax(); |
|
} while (!need_resched()); |
|
|
|
__set_current_state(TASK_RUNNING); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(blk_poll); |
|
|
|
unsigned int blk_mq_rq_cpu(struct request *rq) |
|
{ |
|
return rq->mq_ctx->cpu; |
|
} |
|
EXPORT_SYMBOL(blk_mq_rq_cpu); |
|
|
|
static int __init blk_mq_init(void) |
|
{ |
|
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);
|
|
|