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9c62110454
If we have scheduling enabled, we jump directly to insert-and-run. That's fine, but we run the queue async and we don't pass in information on whether we can block from this context or not. Fixup both these cases. Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Omar Sandoval <osandov@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2928 lines
70 KiB
C
2928 lines
70 KiB
C
/*
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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 <trace/events/block.h>
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#include <linux/blk-mq.h>
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#include "blk.h"
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#include "blk-mq.h"
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#include "blk-mq-tag.h"
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#include "blk-stat.h"
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#include "blk-wbt.h"
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#include "blk-mq-sched.h"
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static DEFINE_MUTEX(all_q_mutex);
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static LIST_HEAD(all_q_list);
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/*
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* Check if any of the ctx's have pending work in this hardware queue
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*/
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bool blk_mq_hctx_has_pending(struct blk_mq_hw_ctx *hctx)
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{
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return sbitmap_any_bit_set(&hctx->ctx_map) ||
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!list_empty_careful(&hctx->dispatch) ||
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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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if (!sbitmap_test_bit(&hctx->ctx_map, ctx->index_hw))
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sbitmap_set_bit(&hctx->ctx_map, ctx->index_hw);
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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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sbitmap_clear_bit(&hctx->ctx_map, ctx->index_hw);
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}
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void blk_mq_freeze_queue_start(struct request_queue *q)
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{
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int freeze_depth;
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freeze_depth = atomic_inc_return(&q->mq_freeze_depth);
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if (freeze_depth == 1) {
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percpu_ref_kill(&q->q_usage_counter);
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blk_mq_run_hw_queues(q, false);
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}
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}
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EXPORT_SYMBOL_GPL(blk_mq_freeze_queue_start);
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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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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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* 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_mq_freeze_queue_start(q);
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blk_mq_freeze_queue_wait(q);
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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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void blk_mq_unfreeze_queue(struct request_queue *q)
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{
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int freeze_depth;
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freeze_depth = atomic_dec_return(&q->mq_freeze_depth);
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WARN_ON_ONCE(freeze_depth < 0);
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if (!freeze_depth) {
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percpu_ref_reinit(&q->q_usage_counter);
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wake_up_all(&q->mq_freeze_wq);
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}
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}
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EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue);
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/**
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* blk_mq_quiesce_queue() - wait until all ongoing queue_rq calls 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. Additionally, it is not prevented that
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* new queue_rq() calls occur unless the queue has been stopped first.
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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_stop_hw_queues(q);
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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->queue_rq_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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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;
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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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* If we are called because the queue has now been marked as
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* dying, we need to ensure that processes currently waiting on
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* the queue are notified as well.
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*/
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wake_up_all(&q->mq_freeze_wq);
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}
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bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)
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{
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return blk_mq_has_free_tags(hctx->tags);
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}
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EXPORT_SYMBOL(blk_mq_can_queue);
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void blk_mq_rq_ctx_init(struct request_queue *q, struct blk_mq_ctx *ctx,
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struct request *rq, unsigned int op)
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{
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INIT_LIST_HEAD(&rq->queuelist);
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/* csd/requeue_work/fifo_time is initialized before use */
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rq->q = q;
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rq->mq_ctx = ctx;
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rq->cmd_flags = op;
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if (blk_queue_io_stat(q))
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rq->rq_flags |= RQF_IO_STAT;
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/* do not touch atomic flags, it needs atomic ops against the timer */
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rq->cpu = -1;
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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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rq->start_time = jiffies;
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#ifdef CONFIG_BLK_CGROUP
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rq->rl = NULL;
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set_start_time_ns(rq);
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rq->io_start_time_ns = 0;
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#endif
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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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rq->special = NULL;
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/* tag was already set */
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rq->errors = 0;
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rq->extra_len = 0;
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INIT_LIST_HEAD(&rq->timeout_list);
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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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rq->next_rq = NULL;
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ctx->rq_dispatched[op_is_sync(op)]++;
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}
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EXPORT_SYMBOL_GPL(blk_mq_rq_ctx_init);
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struct request *__blk_mq_alloc_request(struct blk_mq_alloc_data *data,
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unsigned int op)
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{
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struct request *rq;
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unsigned int tag;
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tag = blk_mq_get_tag(data);
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if (tag != BLK_MQ_TAG_FAIL) {
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struct blk_mq_tags *tags = blk_mq_tags_from_data(data);
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rq = tags->static_rqs[tag];
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if (data->flags & BLK_MQ_REQ_INTERNAL) {
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rq->tag = -1;
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rq->internal_tag = tag;
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} else {
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if (blk_mq_tag_busy(data->hctx)) {
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rq->rq_flags = RQF_MQ_INFLIGHT;
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atomic_inc(&data->hctx->nr_active);
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}
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rq->tag = tag;
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rq->internal_tag = -1;
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data->hctx->tags->rqs[rq->tag] = rq;
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}
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blk_mq_rq_ctx_init(data->q, data->ctx, rq, op);
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return rq;
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}
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return NULL;
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}
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EXPORT_SYMBOL_GPL(__blk_mq_alloc_request);
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struct request *blk_mq_alloc_request(struct request_queue *q, int rw,
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unsigned int flags)
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{
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struct blk_mq_alloc_data alloc_data = { .flags = flags };
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struct request *rq;
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int ret;
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ret = blk_queue_enter(q, flags & BLK_MQ_REQ_NOWAIT);
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if (ret)
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return ERR_PTR(ret);
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rq = blk_mq_sched_get_request(q, NULL, rw, &alloc_data);
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blk_mq_put_ctx(alloc_data.ctx);
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blk_queue_exit(q);
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if (!rq)
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return ERR_PTR(-EWOULDBLOCK);
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rq->__data_len = 0;
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rq->__sector = (sector_t) -1;
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rq->bio = rq->biotail = NULL;
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return rq;
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}
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EXPORT_SYMBOL(blk_mq_alloc_request);
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struct request *blk_mq_alloc_request_hctx(struct request_queue *q, int rw,
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unsigned int flags, unsigned int hctx_idx)
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{
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struct blk_mq_alloc_data alloc_data = { .flags = flags };
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struct request *rq;
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unsigned int cpu;
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int ret;
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/*
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* If the tag allocator sleeps we could get an allocation for a
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* different hardware context. No need to complicate the low level
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* allocator for this for the rare use case of a command tied to
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* a specific queue.
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*/
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if (WARN_ON_ONCE(!(flags & BLK_MQ_REQ_NOWAIT)))
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return ERR_PTR(-EINVAL);
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if (hctx_idx >= q->nr_hw_queues)
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return ERR_PTR(-EIO);
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ret = blk_queue_enter(q, true);
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if (ret)
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return ERR_PTR(ret);
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/*
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* Check if the hardware context is actually mapped to anything.
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* If not tell the caller that it should skip this queue.
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*/
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alloc_data.hctx = q->queue_hw_ctx[hctx_idx];
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if (!blk_mq_hw_queue_mapped(alloc_data.hctx)) {
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blk_queue_exit(q);
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return ERR_PTR(-EXDEV);
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}
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cpu = cpumask_first(alloc_data.hctx->cpumask);
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alloc_data.ctx = __blk_mq_get_ctx(q, cpu);
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rq = blk_mq_sched_get_request(q, NULL, rw, &alloc_data);
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blk_mq_put_ctx(alloc_data.ctx);
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blk_queue_exit(q);
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if (!rq)
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return ERR_PTR(-EWOULDBLOCK);
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return rq;
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}
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EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);
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void __blk_mq_finish_request(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
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struct request *rq)
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{
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const int sched_tag = rq->internal_tag;
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struct request_queue *q = rq->q;
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if (rq->rq_flags & RQF_MQ_INFLIGHT)
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atomic_dec(&hctx->nr_active);
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wbt_done(q->rq_wb, &rq->issue_stat);
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rq->rq_flags = 0;
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clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
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clear_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags);
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if (rq->tag != -1)
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blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag);
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if (sched_tag != -1)
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blk_mq_sched_completed_request(hctx, rq);
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blk_mq_sched_restart_queues(hctx);
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blk_queue_exit(q);
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}
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static void blk_mq_finish_hctx_request(struct blk_mq_hw_ctx *hctx,
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struct request *rq)
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{
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struct blk_mq_ctx *ctx = rq->mq_ctx;
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ctx->rq_completed[rq_is_sync(rq)]++;
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__blk_mq_finish_request(hctx, ctx, rq);
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}
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void blk_mq_finish_request(struct request *rq)
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{
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blk_mq_finish_hctx_request(blk_mq_map_queue(rq->q, rq->mq_ctx->cpu), rq);
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}
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void blk_mq_free_request(struct request *rq)
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{
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blk_mq_sched_put_request(rq);
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}
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EXPORT_SYMBOL_GPL(blk_mq_free_request);
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inline void __blk_mq_end_request(struct request *rq, int error)
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{
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blk_account_io_done(rq);
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if (rq->end_io) {
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wbt_done(rq->q->rq_wb, &rq->issue_stat);
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rq->end_io(rq, error);
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} else {
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if (unlikely(blk_bidi_rq(rq)))
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blk_mq_free_request(rq->next_rq);
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blk_mq_free_request(rq);
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}
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}
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EXPORT_SYMBOL(__blk_mq_end_request);
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void blk_mq_end_request(struct request *rq, int error)
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{
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if (blk_update_request(rq, error, blk_rq_bytes(rq)))
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BUG();
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__blk_mq_end_request(rq, error);
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}
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EXPORT_SYMBOL(blk_mq_end_request);
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static void __blk_mq_complete_request_remote(void *data)
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{
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struct request *rq = data;
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rq->q->softirq_done_fn(rq);
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}
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static void blk_mq_ipi_complete_request(struct request *rq)
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{
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struct blk_mq_ctx *ctx = rq->mq_ctx;
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bool shared = false;
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int cpu;
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if (!test_bit(QUEUE_FLAG_SAME_COMP, &rq->q->queue_flags)) {
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rq->q->softirq_done_fn(rq);
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return;
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}
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cpu = get_cpu();
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if (!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags))
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shared = cpus_share_cache(cpu, ctx->cpu);
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if (cpu != ctx->cpu && !shared && cpu_online(ctx->cpu)) {
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rq->csd.func = __blk_mq_complete_request_remote;
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rq->csd.info = rq;
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rq->csd.flags = 0;
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smp_call_function_single_async(ctx->cpu, &rq->csd);
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} else {
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rq->q->softirq_done_fn(rq);
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}
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put_cpu();
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}
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static void blk_mq_stat_add(struct request *rq)
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{
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if (rq->rq_flags & RQF_STATS) {
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/*
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* We could rq->mq_ctx here, but there's less of a risk
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* of races if we have the completion event add the stats
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* to the local software queue.
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*/
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struct blk_mq_ctx *ctx;
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ctx = __blk_mq_get_ctx(rq->q, raw_smp_processor_id());
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blk_stat_add(&ctx->stat[rq_data_dir(rq)], rq);
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}
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}
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static void __blk_mq_complete_request(struct request *rq)
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{
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struct request_queue *q = rq->q;
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blk_mq_stat_add(rq);
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if (!q->softirq_done_fn)
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blk_mq_end_request(rq, rq->errors);
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else
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blk_mq_ipi_complete_request(rq);
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}
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|
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/**
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* blk_mq_complete_request - end I/O on a request
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* @rq: the request being processed
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*
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* Description:
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* Ends all I/O on a request. It does not handle partial completions.
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* The actual completion happens out-of-order, through a IPI handler.
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**/
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void blk_mq_complete_request(struct request *rq, int error)
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{
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struct request_queue *q = rq->q;
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if (unlikely(blk_should_fake_timeout(q)))
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return;
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if (!blk_mark_rq_complete(rq)) {
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rq->errors = error;
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__blk_mq_complete_request(rq);
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}
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}
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EXPORT_SYMBOL(blk_mq_complete_request);
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int blk_mq_request_started(struct request *rq)
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{
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return test_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
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}
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EXPORT_SYMBOL_GPL(blk_mq_request_started);
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|
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void blk_mq_start_request(struct request *rq)
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{
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struct request_queue *q = rq->q;
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blk_mq_sched_started_request(rq);
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trace_block_rq_issue(q, rq);
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|
|
if (test_bit(QUEUE_FLAG_STATS, &q->queue_flags)) {
|
|
blk_stat_set_issue_time(&rq->issue_stat);
|
|
rq->rq_flags |= RQF_STATS;
|
|
wbt_issue(q->rq_wb, &rq->issue_stat);
|
|
}
|
|
|
|
blk_add_timer(rq);
|
|
|
|
/*
|
|
* Ensure that ->deadline is visible before set the started
|
|
* flag and clear the completed flag.
|
|
*/
|
|
smp_mb__before_atomic();
|
|
|
|
/*
|
|
* Mark us as started and clear complete. Complete might have been
|
|
* set if requeue raced with timeout, which then marked it as
|
|
* complete. So be sure to clear complete again when we start
|
|
* the request, otherwise we'll ignore the completion event.
|
|
*/
|
|
if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags))
|
|
set_bit(REQ_ATOM_STARTED, &rq->atomic_flags);
|
|
if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags))
|
|
clear_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags);
|
|
|
|
if (q->dma_drain_size && blk_rq_bytes(rq)) {
|
|
/*
|
|
* Make sure space for the drain appears. We know we can do
|
|
* this because max_hw_segments has been adjusted to be one
|
|
* fewer than the device can handle.
|
|
*/
|
|
rq->nr_phys_segments++;
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_start_request);
|
|
|
|
static void __blk_mq_requeue_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
trace_block_rq_requeue(q, rq);
|
|
wbt_requeue(q->rq_wb, &rq->issue_stat);
|
|
blk_mq_sched_requeue_request(rq);
|
|
|
|
if (test_and_clear_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) {
|
|
if (q->dma_drain_size && blk_rq_bytes(rq))
|
|
rq->nr_phys_segments--;
|
|
}
|
|
}
|
|
|
|
void blk_mq_requeue_request(struct request *rq, bool kick_requeue_list)
|
|
{
|
|
__blk_mq_requeue_request(rq);
|
|
|
|
BUG_ON(blk_queued_rq(rq));
|
|
blk_mq_add_to_requeue_list(rq, true, kick_requeue_list);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_requeue_request);
|
|
|
|
static void blk_mq_requeue_work(struct work_struct *work)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(work, struct request_queue, requeue_work.work);
|
|
LIST_HEAD(rq_list);
|
|
struct request *rq, *next;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&q->requeue_lock, flags);
|
|
list_splice_init(&q->requeue_list, &rq_list);
|
|
spin_unlock_irqrestore(&q->requeue_lock, flags);
|
|
|
|
list_for_each_entry_safe(rq, next, &rq_list, queuelist) {
|
|
if (!(rq->rq_flags & RQF_SOFTBARRIER))
|
|
continue;
|
|
|
|
rq->rq_flags &= ~RQF_SOFTBARRIER;
|
|
list_del_init(&rq->queuelist);
|
|
blk_mq_sched_insert_request(rq, true, false, false, true);
|
|
}
|
|
|
|
while (!list_empty(&rq_list)) {
|
|
rq = list_entry(rq_list.next, struct request, queuelist);
|
|
list_del_init(&rq->queuelist);
|
|
blk_mq_sched_insert_request(rq, false, false, false, true);
|
|
}
|
|
|
|
blk_mq_run_hw_queues(q, false);
|
|
}
|
|
|
|
void blk_mq_add_to_requeue_list(struct request *rq, bool at_head,
|
|
bool kick_requeue_list)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* We abuse this flag that is otherwise used by the I/O scheduler to
|
|
* request head insertation from the workqueue.
|
|
*/
|
|
BUG_ON(rq->rq_flags & RQF_SOFTBARRIER);
|
|
|
|
spin_lock_irqsave(&q->requeue_lock, flags);
|
|
if (at_head) {
|
|
rq->rq_flags |= RQF_SOFTBARRIER;
|
|
list_add(&rq->queuelist, &q->requeue_list);
|
|
} else {
|
|
list_add_tail(&rq->queuelist, &q->requeue_list);
|
|
}
|
|
spin_unlock_irqrestore(&q->requeue_lock, flags);
|
|
|
|
if (kick_requeue_list)
|
|
blk_mq_kick_requeue_list(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_add_to_requeue_list);
|
|
|
|
void blk_mq_kick_requeue_list(struct request_queue *q)
|
|
{
|
|
kblockd_schedule_delayed_work(&q->requeue_work, 0);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_kick_requeue_list);
|
|
|
|
void blk_mq_delay_kick_requeue_list(struct request_queue *q,
|
|
unsigned long msecs)
|
|
{
|
|
kblockd_schedule_delayed_work(&q->requeue_work,
|
|
msecs_to_jiffies(msecs));
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_delay_kick_requeue_list);
|
|
|
|
void blk_mq_abort_requeue_list(struct request_queue *q)
|
|
{
|
|
unsigned long flags;
|
|
LIST_HEAD(rq_list);
|
|
|
|
spin_lock_irqsave(&q->requeue_lock, flags);
|
|
list_splice_init(&q->requeue_list, &rq_list);
|
|
spin_unlock_irqrestore(&q->requeue_lock, flags);
|
|
|
|
while (!list_empty(&rq_list)) {
|
|
struct request *rq;
|
|
|
|
rq = list_first_entry(&rq_list, struct request, queuelist);
|
|
list_del_init(&rq->queuelist);
|
|
rq->errors = -EIO;
|
|
blk_mq_end_request(rq, rq->errors);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_abort_requeue_list);
|
|
|
|
struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag)
|
|
{
|
|
if (tag < tags->nr_tags) {
|
|
prefetch(tags->rqs[tag]);
|
|
return tags->rqs[tag];
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_tag_to_rq);
|
|
|
|
struct blk_mq_timeout_data {
|
|
unsigned long next;
|
|
unsigned int next_set;
|
|
};
|
|
|
|
void blk_mq_rq_timed_out(struct request *req, bool reserved)
|
|
{
|
|
const struct blk_mq_ops *ops = req->q->mq_ops;
|
|
enum blk_eh_timer_return ret = BLK_EH_RESET_TIMER;
|
|
|
|
/*
|
|
* We know that complete is set at this point. If STARTED isn't set
|
|
* anymore, then the request isn't active and the "timeout" should
|
|
* just be ignored. This can happen due to the bitflag ordering.
|
|
* Timeout first checks if STARTED is set, and if it is, assumes
|
|
* the request is active. But if we race with completion, then
|
|
* we both flags will get cleared. So check here again, and ignore
|
|
* a timeout event with a request that isn't active.
|
|
*/
|
|
if (!test_bit(REQ_ATOM_STARTED, &req->atomic_flags))
|
|
return;
|
|
|
|
if (ops->timeout)
|
|
ret = ops->timeout(req, reserved);
|
|
|
|
switch (ret) {
|
|
case BLK_EH_HANDLED:
|
|
__blk_mq_complete_request(req);
|
|
break;
|
|
case BLK_EH_RESET_TIMER:
|
|
blk_add_timer(req);
|
|
blk_clear_rq_complete(req);
|
|
break;
|
|
case BLK_EH_NOT_HANDLED:
|
|
break;
|
|
default:
|
|
printk(KERN_ERR "block: bad eh return: %d\n", ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq, void *priv, bool reserved)
|
|
{
|
|
struct blk_mq_timeout_data *data = priv;
|
|
|
|
if (!test_bit(REQ_ATOM_STARTED, &rq->atomic_flags)) {
|
|
/*
|
|
* If a request wasn't started before the queue was
|
|
* marked dying, kill it here or it'll go unnoticed.
|
|
*/
|
|
if (unlikely(blk_queue_dying(rq->q))) {
|
|
rq->errors = -EIO;
|
|
blk_mq_end_request(rq, rq->errors);
|
|
}
|
|
return;
|
|
}
|
|
|
|
if (time_after_eq(jiffies, rq->deadline)) {
|
|
if (!blk_mark_rq_complete(rq))
|
|
blk_mq_rq_timed_out(rq, reserved);
|
|
} else if (!data->next_set || time_after(data->next, rq->deadline)) {
|
|
data->next = rq->deadline;
|
|
data->next_set = 1;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_timeout_work(struct work_struct *work)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(work, struct request_queue, timeout_work);
|
|
struct blk_mq_timeout_data data = {
|
|
.next = 0,
|
|
.next_set = 0,
|
|
};
|
|
int i;
|
|
|
|
/* A deadlock might occur if a request is stuck requiring a
|
|
* timeout at the same time a queue freeze is waiting
|
|
* completion, since the timeout code would not be able to
|
|
* acquire the queue reference here.
|
|
*
|
|
* That's why we don't use blk_queue_enter here; instead, we use
|
|
* percpu_ref_tryget directly, because we need to be able to
|
|
* obtain a reference even in the short window between the queue
|
|
* starting to freeze, by dropping the first reference in
|
|
* blk_mq_freeze_queue_start, and the moment the last request is
|
|
* consumed, marked by the instant q_usage_counter reaches
|
|
* zero.
|
|
*/
|
|
if (!percpu_ref_tryget(&q->q_usage_counter))
|
|
return;
|
|
|
|
blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data);
|
|
|
|
if (data.next_set) {
|
|
data.next = blk_rq_timeout(round_jiffies_up(data.next));
|
|
mod_timer(&q->timeout, data.next);
|
|
} else {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
/* the hctx may be unmapped, so check it here */
|
|
if (blk_mq_hw_queue_mapped(hctx))
|
|
blk_mq_tag_idle(hctx);
|
|
}
|
|
}
|
|
blk_queue_exit(q);
|
|
}
|
|
|
|
/*
|
|
* Reverse check our software queue for entries that we could potentially
|
|
* merge with. Currently includes a hand-wavy stop count of 8, to not spend
|
|
* too much time checking for merges.
|
|
*/
|
|
static bool blk_mq_attempt_merge(struct request_queue *q,
|
|
struct blk_mq_ctx *ctx, struct bio *bio)
|
|
{
|
|
struct request *rq;
|
|
int checked = 8;
|
|
|
|
list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) {
|
|
bool merged = false;
|
|
|
|
if (!checked--)
|
|
break;
|
|
|
|
if (!blk_rq_merge_ok(rq, bio))
|
|
continue;
|
|
|
|
switch (blk_try_merge(rq, bio)) {
|
|
case ELEVATOR_BACK_MERGE:
|
|
if (blk_mq_sched_allow_merge(q, rq, bio))
|
|
merged = bio_attempt_back_merge(q, rq, bio);
|
|
break;
|
|
case ELEVATOR_FRONT_MERGE:
|
|
if (blk_mq_sched_allow_merge(q, rq, bio))
|
|
merged = bio_attempt_front_merge(q, rq, bio);
|
|
break;
|
|
case ELEVATOR_DISCARD_MERGE:
|
|
merged = bio_attempt_discard_merge(q, rq, bio);
|
|
break;
|
|
default:
|
|
continue;
|
|
}
|
|
|
|
if (merged)
|
|
ctx->rq_merged++;
|
|
return merged;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
struct flush_busy_ctx_data {
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct list_head *list;
|
|
};
|
|
|
|
static bool flush_busy_ctx(struct sbitmap *sb, unsigned int bitnr, void *data)
|
|
{
|
|
struct flush_busy_ctx_data *flush_data = data;
|
|
struct blk_mq_hw_ctx *hctx = flush_data->hctx;
|
|
struct blk_mq_ctx *ctx = hctx->ctxs[bitnr];
|
|
|
|
sbitmap_clear_bit(sb, bitnr);
|
|
spin_lock(&ctx->lock);
|
|
list_splice_tail_init(&ctx->rq_list, flush_data->list);
|
|
spin_unlock(&ctx->lock);
|
|
return true;
|
|
}
|
|
|
|
/*
|
|
* Process software queues that have been marked busy, splicing them
|
|
* to the for-dispatch
|
|
*/
|
|
void blk_mq_flush_busy_ctxs(struct blk_mq_hw_ctx *hctx, struct list_head *list)
|
|
{
|
|
struct flush_busy_ctx_data data = {
|
|
.hctx = hctx,
|
|
.list = list,
|
|
};
|
|
|
|
sbitmap_for_each_set(&hctx->ctx_map, flush_busy_ctx, &data);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_flush_busy_ctxs);
|
|
|
|
static inline unsigned int queued_to_index(unsigned int queued)
|
|
{
|
|
if (!queued)
|
|
return 0;
|
|
|
|
return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
|
|
}
|
|
|
|
bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx,
|
|
bool wait)
|
|
{
|
|
struct blk_mq_alloc_data data = {
|
|
.q = rq->q,
|
|
.hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu),
|
|
.flags = wait ? 0 : BLK_MQ_REQ_NOWAIT,
|
|
};
|
|
|
|
if (rq->tag != -1) {
|
|
done:
|
|
if (hctx)
|
|
*hctx = data.hctx;
|
|
return true;
|
|
}
|
|
|
|
if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag))
|
|
data.flags |= BLK_MQ_REQ_RESERVED;
|
|
|
|
rq->tag = blk_mq_get_tag(&data);
|
|
if (rq->tag >= 0) {
|
|
if (blk_mq_tag_busy(data.hctx)) {
|
|
rq->rq_flags |= RQF_MQ_INFLIGHT;
|
|
atomic_inc(&data.hctx->nr_active);
|
|
}
|
|
data.hctx->tags->rqs[rq->tag] = rq;
|
|
goto done;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
static void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
blk_mq_put_tag(hctx, hctx->tags, rq->mq_ctx, rq->tag);
|
|
rq->tag = -1;
|
|
|
|
if (rq->rq_flags & RQF_MQ_INFLIGHT) {
|
|
rq->rq_flags &= ~RQF_MQ_INFLIGHT;
|
|
atomic_dec(&hctx->nr_active);
|
|
}
|
|
}
|
|
|
|
static void blk_mq_put_driver_tag_hctx(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
if (rq->tag == -1 || rq->internal_tag == -1)
|
|
return;
|
|
|
|
__blk_mq_put_driver_tag(hctx, rq);
|
|
}
|
|
|
|
static void blk_mq_put_driver_tag(struct request *rq)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
if (rq->tag == -1 || rq->internal_tag == -1)
|
|
return;
|
|
|
|
hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu);
|
|
__blk_mq_put_driver_tag(hctx, rq);
|
|
}
|
|
|
|
/*
|
|
* If we fail getting a driver tag because all the driver tags are already
|
|
* assigned and on the dispatch list, BUT the first entry does not have a
|
|
* tag, then we could deadlock. For that case, move entries with assigned
|
|
* driver tags to the front, leaving the set of tagged requests in the
|
|
* same order, and the untagged set in the same order.
|
|
*/
|
|
static bool reorder_tags_to_front(struct list_head *list)
|
|
{
|
|
struct request *rq, *tmp, *first = NULL;
|
|
|
|
list_for_each_entry_safe_reverse(rq, tmp, list, queuelist) {
|
|
if (rq == first)
|
|
break;
|
|
if (rq->tag != -1) {
|
|
list_move(&rq->queuelist, list);
|
|
if (!first)
|
|
first = rq;
|
|
}
|
|
}
|
|
|
|
return first != NULL;
|
|
}
|
|
|
|
static int blk_mq_dispatch_wake(wait_queue_t *wait, unsigned mode, int flags,
|
|
void *key)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
hctx = container_of(wait, struct blk_mq_hw_ctx, dispatch_wait);
|
|
|
|
list_del(&wait->task_list);
|
|
clear_bit_unlock(BLK_MQ_S_TAG_WAITING, &hctx->state);
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
return 1;
|
|
}
|
|
|
|
static bool blk_mq_dispatch_wait_add(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
struct sbq_wait_state *ws;
|
|
|
|
/*
|
|
* The TAG_WAITING bit serves as a lock protecting hctx->dispatch_wait.
|
|
* The thread which wins the race to grab this bit adds the hardware
|
|
* queue to the wait queue.
|
|
*/
|
|
if (test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state) ||
|
|
test_and_set_bit_lock(BLK_MQ_S_TAG_WAITING, &hctx->state))
|
|
return false;
|
|
|
|
init_waitqueue_func_entry(&hctx->dispatch_wait, blk_mq_dispatch_wake);
|
|
ws = bt_wait_ptr(&hctx->tags->bitmap_tags, hctx);
|
|
|
|
/*
|
|
* As soon as this returns, it's no longer safe to fiddle with
|
|
* hctx->dispatch_wait, since a completion can wake up the wait queue
|
|
* and unlock the bit.
|
|
*/
|
|
add_wait_queue(&ws->wait, &hctx->dispatch_wait);
|
|
return true;
|
|
}
|
|
|
|
bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list)
|
|
{
|
|
struct request_queue *q = hctx->queue;
|
|
struct request *rq;
|
|
LIST_HEAD(driver_list);
|
|
struct list_head *dptr;
|
|
int queued, ret = BLK_MQ_RQ_QUEUE_OK;
|
|
|
|
/*
|
|
* Start off with dptr being NULL, so we start the first request
|
|
* immediately, even if we have more pending.
|
|
*/
|
|
dptr = NULL;
|
|
|
|
/*
|
|
* Now process all the entries, sending them to the driver.
|
|
*/
|
|
queued = 0;
|
|
while (!list_empty(list)) {
|
|
struct blk_mq_queue_data bd;
|
|
|
|
rq = list_first_entry(list, struct request, queuelist);
|
|
if (!blk_mq_get_driver_tag(rq, &hctx, false)) {
|
|
if (!queued && reorder_tags_to_front(list))
|
|
continue;
|
|
|
|
/*
|
|
* The initial allocation attempt failed, so we need to
|
|
* rerun the hardware queue when a tag is freed.
|
|
*/
|
|
if (blk_mq_dispatch_wait_add(hctx)) {
|
|
/*
|
|
* It's possible that a tag was freed in the
|
|
* window between the allocation failure and
|
|
* adding the hardware queue to the wait queue.
|
|
*/
|
|
if (!blk_mq_get_driver_tag(rq, &hctx, false))
|
|
break;
|
|
} else {
|
|
break;
|
|
}
|
|
}
|
|
|
|
list_del_init(&rq->queuelist);
|
|
|
|
bd.rq = rq;
|
|
bd.list = dptr;
|
|
|
|
/*
|
|
* Flag last if we have no more requests, or if we have more
|
|
* but can't assign a driver tag to it.
|
|
*/
|
|
if (list_empty(list))
|
|
bd.last = true;
|
|
else {
|
|
struct request *nxt;
|
|
|
|
nxt = list_first_entry(list, struct request, queuelist);
|
|
bd.last = !blk_mq_get_driver_tag(nxt, NULL, false);
|
|
}
|
|
|
|
ret = q->mq_ops->queue_rq(hctx, &bd);
|
|
switch (ret) {
|
|
case BLK_MQ_RQ_QUEUE_OK:
|
|
queued++;
|
|
break;
|
|
case BLK_MQ_RQ_QUEUE_BUSY:
|
|
blk_mq_put_driver_tag_hctx(hctx, rq);
|
|
list_add(&rq->queuelist, list);
|
|
__blk_mq_requeue_request(rq);
|
|
break;
|
|
default:
|
|
pr_err("blk-mq: bad return on queue: %d\n", ret);
|
|
case BLK_MQ_RQ_QUEUE_ERROR:
|
|
rq->errors = -EIO;
|
|
blk_mq_end_request(rq, rq->errors);
|
|
break;
|
|
}
|
|
|
|
if (ret == BLK_MQ_RQ_QUEUE_BUSY)
|
|
break;
|
|
|
|
/*
|
|
* We've done the first request. If we have more than 1
|
|
* left in the list, set dptr to defer issue.
|
|
*/
|
|
if (!dptr && list->next != list->prev)
|
|
dptr = &driver_list;
|
|
}
|
|
|
|
hctx->dispatched[queued_to_index(queued)]++;
|
|
|
|
/*
|
|
* Any items that need requeuing? Stuff them into hctx->dispatch,
|
|
* that is where we will continue on next queue run.
|
|
*/
|
|
if (!list_empty(list)) {
|
|
/*
|
|
* If we got a driver tag for the next request already,
|
|
* free it again.
|
|
*/
|
|
rq = list_first_entry(list, struct request, queuelist);
|
|
blk_mq_put_driver_tag(rq);
|
|
|
|
spin_lock(&hctx->lock);
|
|
list_splice_init(list, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
/*
|
|
* the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but
|
|
* it's possible the queue is stopped and restarted again
|
|
* before this. Queue restart will dispatch requests. And since
|
|
* requests in rq_list aren't added into hctx->dispatch yet,
|
|
* the requests in rq_list might get lost.
|
|
*
|
|
* blk_mq_run_hw_queue() already checks the STOPPED bit
|
|
*
|
|
* If RESTART or TAG_WAITING is set, then let completion restart
|
|
* the queue instead of potentially looping here.
|
|
*/
|
|
if (!blk_mq_sched_needs_restart(hctx) &&
|
|
!test_bit(BLK_MQ_S_TAG_WAITING, &hctx->state))
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
}
|
|
|
|
return queued != 0;
|
|
}
|
|
|
|
static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
int srcu_idx;
|
|
|
|
WARN_ON(!cpumask_test_cpu(raw_smp_processor_id(), hctx->cpumask) &&
|
|
cpu_online(hctx->next_cpu));
|
|
|
|
if (!(hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
rcu_read_lock();
|
|
blk_mq_sched_dispatch_requests(hctx);
|
|
rcu_read_unlock();
|
|
} else {
|
|
srcu_idx = srcu_read_lock(&hctx->queue_rq_srcu);
|
|
blk_mq_sched_dispatch_requests(hctx);
|
|
srcu_read_unlock(&hctx->queue_rq_srcu, srcu_idx);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* It'd be great if the workqueue API had a way to pass
|
|
* in a mask and had some smarts for more clever placement.
|
|
* For now we just round-robin here, switching for every
|
|
* BLK_MQ_CPU_WORK_BATCH queued items.
|
|
*/
|
|
static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
if (hctx->queue->nr_hw_queues == 1)
|
|
return WORK_CPU_UNBOUND;
|
|
|
|
if (--hctx->next_cpu_batch <= 0) {
|
|
int next_cpu;
|
|
|
|
next_cpu = cpumask_next(hctx->next_cpu, hctx->cpumask);
|
|
if (next_cpu >= nr_cpu_ids)
|
|
next_cpu = cpumask_first(hctx->cpumask);
|
|
|
|
hctx->next_cpu = next_cpu;
|
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
|
|
}
|
|
|
|
return hctx->next_cpu;
|
|
}
|
|
|
|
void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async)
|
|
{
|
|
if (unlikely(blk_mq_hctx_stopped(hctx) ||
|
|
!blk_mq_hw_queue_mapped(hctx)))
|
|
return;
|
|
|
|
if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
int cpu = get_cpu();
|
|
if (cpumask_test_cpu(cpu, hctx->cpumask)) {
|
|
__blk_mq_run_hw_queue(hctx);
|
|
put_cpu();
|
|
return;
|
|
}
|
|
|
|
put_cpu();
|
|
}
|
|
|
|
kblockd_schedule_work_on(blk_mq_hctx_next_cpu(hctx), &hctx->run_work);
|
|
}
|
|
|
|
void blk_mq_run_hw_queues(struct request_queue *q, bool async)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (!blk_mq_hctx_has_pending(hctx) ||
|
|
blk_mq_hctx_stopped(hctx))
|
|
continue;
|
|
|
|
blk_mq_run_hw_queue(hctx, async);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_run_hw_queues);
|
|
|
|
/**
|
|
* blk_mq_queue_stopped() - check whether one or more hctxs have been stopped
|
|
* @q: request queue.
|
|
*
|
|
* The caller is responsible for serializing this function against
|
|
* blk_mq_{start,stop}_hw_queue().
|
|
*/
|
|
bool blk_mq_queue_stopped(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
if (blk_mq_hctx_stopped(hctx))
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_queue_stopped);
|
|
|
|
void blk_mq_stop_hw_queue(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
cancel_work(&hctx->run_work);
|
|
cancel_delayed_work(&hctx->delay_work);
|
|
set_bit(BLK_MQ_S_STOPPED, &hctx->state);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_stop_hw_queue);
|
|
|
|
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);
|
|
|
|
__blk_mq_run_hw_queue(hctx);
|
|
}
|
|
|
|
static void blk_mq_delay_work_fn(struct work_struct *work)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
hctx = container_of(work, struct blk_mq_hw_ctx, delay_work.work);
|
|
|
|
if (test_and_clear_bit(BLK_MQ_S_STOPPED, &hctx->state))
|
|
__blk_mq_run_hw_queue(hctx);
|
|
}
|
|
|
|
void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
|
|
{
|
|
if (unlikely(!blk_mq_hw_queue_mapped(hctx)))
|
|
return;
|
|
|
|
blk_mq_stop_hw_queue(hctx);
|
|
kblockd_schedule_delayed_work_on(blk_mq_hctx_next_cpu(hctx),
|
|
&hctx->delay_work, msecs_to_jiffies(msecs));
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_delay_queue);
|
|
|
|
static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq,
|
|
bool at_head)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
|
|
trace_block_rq_insert(hctx->queue, rq);
|
|
|
|
if (at_head)
|
|
list_add(&rq->queuelist, &ctx->rq_list);
|
|
else
|
|
list_add_tail(&rq->queuelist, &ctx->rq_list);
|
|
}
|
|
|
|
void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
|
|
bool at_head)
|
|
{
|
|
struct blk_mq_ctx *ctx = rq->mq_ctx;
|
|
|
|
__blk_mq_insert_req_list(hctx, rq, at_head);
|
|
blk_mq_hctx_mark_pending(hctx, ctx);
|
|
}
|
|
|
|
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
|
|
struct list_head *list)
|
|
|
|
{
|
|
/*
|
|
* preemption doesn't flush plug list, so it's possible ctx->cpu is
|
|
* offline now
|
|
*/
|
|
spin_lock(&ctx->lock);
|
|
while (!list_empty(list)) {
|
|
struct request *rq;
|
|
|
|
rq = list_first_entry(list, struct request, queuelist);
|
|
BUG_ON(rq->mq_ctx != ctx);
|
|
list_del_init(&rq->queuelist);
|
|
__blk_mq_insert_req_list(hctx, rq, false);
|
|
}
|
|
blk_mq_hctx_mark_pending(hctx, ctx);
|
|
spin_unlock(&ctx->lock);
|
|
}
|
|
|
|
static int plug_ctx_cmp(void *priv, struct list_head *a, struct list_head *b)
|
|
{
|
|
struct request *rqa = container_of(a, struct request, queuelist);
|
|
struct request *rqb = container_of(b, struct request, queuelist);
|
|
|
|
return !(rqa->mq_ctx < rqb->mq_ctx ||
|
|
(rqa->mq_ctx == rqb->mq_ctx &&
|
|
blk_rq_pos(rqa) < blk_rq_pos(rqb)));
|
|
}
|
|
|
|
void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule)
|
|
{
|
|
struct blk_mq_ctx *this_ctx;
|
|
struct request_queue *this_q;
|
|
struct request *rq;
|
|
LIST_HEAD(list);
|
|
LIST_HEAD(ctx_list);
|
|
unsigned int depth;
|
|
|
|
list_splice_init(&plug->mq_list, &list);
|
|
|
|
list_sort(NULL, &list, plug_ctx_cmp);
|
|
|
|
this_q = NULL;
|
|
this_ctx = NULL;
|
|
depth = 0;
|
|
|
|
while (!list_empty(&list)) {
|
|
rq = list_entry_rq(list.next);
|
|
list_del_init(&rq->queuelist);
|
|
BUG_ON(!rq->q);
|
|
if (rq->mq_ctx != this_ctx) {
|
|
if (this_ctx) {
|
|
trace_block_unplug(this_q, depth, from_schedule);
|
|
blk_mq_sched_insert_requests(this_q, this_ctx,
|
|
&ctx_list,
|
|
from_schedule);
|
|
}
|
|
|
|
this_ctx = rq->mq_ctx;
|
|
this_q = rq->q;
|
|
depth = 0;
|
|
}
|
|
|
|
depth++;
|
|
list_add_tail(&rq->queuelist, &ctx_list);
|
|
}
|
|
|
|
/*
|
|
* If 'this_ctx' is set, we know we have entries to complete
|
|
* on 'ctx_list'. Do those.
|
|
*/
|
|
if (this_ctx) {
|
|
trace_block_unplug(this_q, depth, from_schedule);
|
|
blk_mq_sched_insert_requests(this_q, this_ctx, &ctx_list,
|
|
from_schedule);
|
|
}
|
|
}
|
|
|
|
static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
|
|
{
|
|
init_request_from_bio(rq, bio);
|
|
|
|
blk_account_io_start(rq, true);
|
|
}
|
|
|
|
static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
|
|
!blk_queue_nomerges(hctx->queue);
|
|
}
|
|
|
|
static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx,
|
|
struct blk_mq_ctx *ctx,
|
|
struct request *rq, struct bio *bio)
|
|
{
|
|
if (!hctx_allow_merges(hctx) || !bio_mergeable(bio)) {
|
|
blk_mq_bio_to_request(rq, bio);
|
|
spin_lock(&ctx->lock);
|
|
insert_rq:
|
|
__blk_mq_insert_request(hctx, rq, false);
|
|
spin_unlock(&ctx->lock);
|
|
return false;
|
|
} else {
|
|
struct request_queue *q = hctx->queue;
|
|
|
|
spin_lock(&ctx->lock);
|
|
if (!blk_mq_attempt_merge(q, ctx, bio)) {
|
|
blk_mq_bio_to_request(rq, bio);
|
|
goto insert_rq;
|
|
}
|
|
|
|
spin_unlock(&ctx->lock);
|
|
__blk_mq_finish_request(hctx, ctx, rq);
|
|
return true;
|
|
}
|
|
}
|
|
|
|
static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
|
|
{
|
|
if (rq->tag != -1)
|
|
return blk_tag_to_qc_t(rq->tag, hctx->queue_num, false);
|
|
|
|
return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);
|
|
}
|
|
|
|
static void blk_mq_try_issue_directly(struct request *rq, blk_qc_t *cookie,
|
|
bool may_sleep)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
struct blk_mq_queue_data bd = {
|
|
.rq = rq,
|
|
.list = NULL,
|
|
.last = 1
|
|
};
|
|
struct blk_mq_hw_ctx *hctx;
|
|
blk_qc_t new_cookie;
|
|
int ret;
|
|
|
|
if (q->elevator)
|
|
goto insert;
|
|
|
|
if (!blk_mq_get_driver_tag(rq, &hctx, false))
|
|
goto insert;
|
|
|
|
new_cookie = request_to_qc_t(hctx, rq);
|
|
|
|
/*
|
|
* For OK queue, we are done. For error, kill it. Any other
|
|
* error (busy), just add it to our list as we previously
|
|
* would have done
|
|
*/
|
|
ret = q->mq_ops->queue_rq(hctx, &bd);
|
|
if (ret == BLK_MQ_RQ_QUEUE_OK) {
|
|
*cookie = new_cookie;
|
|
return;
|
|
}
|
|
|
|
__blk_mq_requeue_request(rq);
|
|
|
|
if (ret == BLK_MQ_RQ_QUEUE_ERROR) {
|
|
*cookie = BLK_QC_T_NONE;
|
|
rq->errors = -EIO;
|
|
blk_mq_end_request(rq, rq->errors);
|
|
return;
|
|
}
|
|
|
|
insert:
|
|
blk_mq_sched_insert_request(rq, false, true, false, may_sleep);
|
|
}
|
|
|
|
/*
|
|
* Multiple hardware queue variant. This will not use per-process plugs,
|
|
* but will attempt to bypass the hctx queueing if we can go straight to
|
|
* hardware for SYNC IO.
|
|
*/
|
|
static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
const int is_sync = op_is_sync(bio->bi_opf);
|
|
const int is_flush_fua = op_is_flush(bio->bi_opf);
|
|
struct blk_mq_alloc_data data = { .flags = 0 };
|
|
struct request *rq;
|
|
unsigned int request_count = 0, srcu_idx;
|
|
struct blk_plug *plug;
|
|
struct request *same_queue_rq = NULL;
|
|
blk_qc_t cookie;
|
|
unsigned int wb_acct;
|
|
|
|
blk_queue_bounce(q, &bio);
|
|
|
|
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
|
|
bio_io_error(bio);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
blk_queue_split(q, &bio, q->bio_split);
|
|
|
|
if (!is_flush_fua && !blk_queue_nomerges(q) &&
|
|
blk_attempt_plug_merge(q, bio, &request_count, &same_queue_rq))
|
|
return BLK_QC_T_NONE;
|
|
|
|
if (blk_mq_sched_bio_merge(q, bio))
|
|
return BLK_QC_T_NONE;
|
|
|
|
wb_acct = wbt_wait(q->rq_wb, bio, NULL);
|
|
|
|
trace_block_getrq(q, bio, bio->bi_opf);
|
|
|
|
rq = blk_mq_sched_get_request(q, bio, bio->bi_opf, &data);
|
|
if (unlikely(!rq)) {
|
|
__wbt_done(q->rq_wb, wb_acct);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
wbt_track(&rq->issue_stat, wb_acct);
|
|
|
|
cookie = request_to_qc_t(data.hctx, rq);
|
|
|
|
if (unlikely(is_flush_fua)) {
|
|
if (q->elevator)
|
|
goto elv_insert;
|
|
blk_mq_bio_to_request(rq, bio);
|
|
blk_insert_flush(rq);
|
|
goto run_queue;
|
|
}
|
|
|
|
plug = current->plug;
|
|
/*
|
|
* If the driver supports defer issued based on 'last', then
|
|
* queue it up like normal since we can potentially save some
|
|
* CPU this way.
|
|
*/
|
|
if (((plug && !blk_queue_nomerges(q)) || is_sync) &&
|
|
!(data.hctx->flags & BLK_MQ_F_DEFER_ISSUE)) {
|
|
struct request *old_rq = NULL;
|
|
|
|
blk_mq_bio_to_request(rq, bio);
|
|
|
|
/*
|
|
* We do limited plugging. If the bio can be merged, do that.
|
|
* Otherwise the existing request in the plug list will be
|
|
* issued. So the plug list will have one request at most
|
|
*/
|
|
if (plug) {
|
|
/*
|
|
* The plug list might get flushed before this. If that
|
|
* happens, same_queue_rq is invalid and plug list is
|
|
* empty
|
|
*/
|
|
if (same_queue_rq && !list_empty(&plug->mq_list)) {
|
|
old_rq = same_queue_rq;
|
|
list_del_init(&old_rq->queuelist);
|
|
}
|
|
list_add_tail(&rq->queuelist, &plug->mq_list);
|
|
} else /* is_sync */
|
|
old_rq = rq;
|
|
blk_mq_put_ctx(data.ctx);
|
|
if (!old_rq)
|
|
goto done;
|
|
|
|
if (!(data.hctx->flags & BLK_MQ_F_BLOCKING)) {
|
|
rcu_read_lock();
|
|
blk_mq_try_issue_directly(old_rq, &cookie, false);
|
|
rcu_read_unlock();
|
|
} else {
|
|
srcu_idx = srcu_read_lock(&data.hctx->queue_rq_srcu);
|
|
blk_mq_try_issue_directly(old_rq, &cookie, true);
|
|
srcu_read_unlock(&data.hctx->queue_rq_srcu, srcu_idx);
|
|
}
|
|
goto done;
|
|
}
|
|
|
|
if (q->elevator) {
|
|
elv_insert:
|
|
blk_mq_put_ctx(data.ctx);
|
|
blk_mq_bio_to_request(rq, bio);
|
|
blk_mq_sched_insert_request(rq, false, true,
|
|
!is_sync || is_flush_fua, true);
|
|
goto done;
|
|
}
|
|
if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
|
|
/*
|
|
* For a SYNC request, send it to the hardware immediately. For
|
|
* an ASYNC request, just ensure that we run it later on. The
|
|
* latter allows for merging opportunities and more efficient
|
|
* dispatching.
|
|
*/
|
|
run_queue:
|
|
blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
|
|
}
|
|
blk_mq_put_ctx(data.ctx);
|
|
done:
|
|
return cookie;
|
|
}
|
|
|
|
/*
|
|
* Single hardware queue variant. This will attempt to use any per-process
|
|
* plug for merging and IO deferral.
|
|
*/
|
|
static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
const int is_sync = op_is_sync(bio->bi_opf);
|
|
const int is_flush_fua = op_is_flush(bio->bi_opf);
|
|
struct blk_plug *plug;
|
|
unsigned int request_count = 0;
|
|
struct blk_mq_alloc_data data = { .flags = 0 };
|
|
struct request *rq;
|
|
blk_qc_t cookie;
|
|
unsigned int wb_acct;
|
|
|
|
blk_queue_bounce(q, &bio);
|
|
|
|
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio)) {
|
|
bio_io_error(bio);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
blk_queue_split(q, &bio, q->bio_split);
|
|
|
|
if (!is_flush_fua && !blk_queue_nomerges(q)) {
|
|
if (blk_attempt_plug_merge(q, bio, &request_count, NULL))
|
|
return BLK_QC_T_NONE;
|
|
} else
|
|
request_count = blk_plug_queued_count(q);
|
|
|
|
if (blk_mq_sched_bio_merge(q, bio))
|
|
return BLK_QC_T_NONE;
|
|
|
|
wb_acct = wbt_wait(q->rq_wb, bio, NULL);
|
|
|
|
trace_block_getrq(q, bio, bio->bi_opf);
|
|
|
|
rq = blk_mq_sched_get_request(q, bio, bio->bi_opf, &data);
|
|
if (unlikely(!rq)) {
|
|
__wbt_done(q->rq_wb, wb_acct);
|
|
return BLK_QC_T_NONE;
|
|
}
|
|
|
|
wbt_track(&rq->issue_stat, wb_acct);
|
|
|
|
cookie = request_to_qc_t(data.hctx, rq);
|
|
|
|
if (unlikely(is_flush_fua)) {
|
|
if (q->elevator)
|
|
goto elv_insert;
|
|
blk_mq_bio_to_request(rq, bio);
|
|
blk_insert_flush(rq);
|
|
goto run_queue;
|
|
}
|
|
|
|
/*
|
|
* A task plug currently exists. Since this is completely lockless,
|
|
* utilize that to temporarily store requests until the task is
|
|
* either done or scheduled away.
|
|
*/
|
|
plug = current->plug;
|
|
if (plug) {
|
|
struct request *last = NULL;
|
|
|
|
blk_mq_bio_to_request(rq, bio);
|
|
|
|
/*
|
|
* @request_count may become stale because of schedule
|
|
* out, so check the list again.
|
|
*/
|
|
if (list_empty(&plug->mq_list))
|
|
request_count = 0;
|
|
if (!request_count)
|
|
trace_block_plug(q);
|
|
else
|
|
last = list_entry_rq(plug->mq_list.prev);
|
|
|
|
blk_mq_put_ctx(data.ctx);
|
|
|
|
if (request_count >= BLK_MAX_REQUEST_COUNT || (last &&
|
|
blk_rq_bytes(last) >= BLK_PLUG_FLUSH_SIZE)) {
|
|
blk_flush_plug_list(plug, false);
|
|
trace_block_plug(q);
|
|
}
|
|
|
|
list_add_tail(&rq->queuelist, &plug->mq_list);
|
|
return cookie;
|
|
}
|
|
|
|
if (q->elevator) {
|
|
elv_insert:
|
|
blk_mq_put_ctx(data.ctx);
|
|
blk_mq_bio_to_request(rq, bio);
|
|
blk_mq_sched_insert_request(rq, false, true,
|
|
!is_sync || is_flush_fua, true);
|
|
goto done;
|
|
}
|
|
if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
|
|
/*
|
|
* For a SYNC request, send it to the hardware immediately. For
|
|
* an ASYNC request, just ensure that we run it later on. The
|
|
* latter allows for merging opportunities and more efficient
|
|
* dispatching.
|
|
*/
|
|
run_queue:
|
|
blk_mq_run_hw_queue(data.hctx, !is_sync || is_flush_fua);
|
|
}
|
|
|
|
blk_mq_put_ctx(data.ctx);
|
|
done:
|
|
return cookie;
|
|
}
|
|
|
|
void blk_mq_free_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
|
|
unsigned int hctx_idx)
|
|
{
|
|
struct page *page;
|
|
|
|
if (tags->rqs && set->ops->exit_request) {
|
|
int i;
|
|
|
|
for (i = 0; i < tags->nr_tags; i++) {
|
|
struct request *rq = tags->static_rqs[i];
|
|
|
|
if (!rq)
|
|
continue;
|
|
set->ops->exit_request(set->driver_data, rq,
|
|
hctx_idx, i);
|
|
tags->static_rqs[i] = NULL;
|
|
}
|
|
}
|
|
|
|
while (!list_empty(&tags->page_list)) {
|
|
page = list_first_entry(&tags->page_list, struct page, lru);
|
|
list_del_init(&page->lru);
|
|
/*
|
|
* Remove kmemleak object previously allocated in
|
|
* blk_mq_init_rq_map().
|
|
*/
|
|
kmemleak_free(page_address(page));
|
|
__free_pages(page, page->private);
|
|
}
|
|
}
|
|
|
|
void blk_mq_free_rq_map(struct blk_mq_tags *tags)
|
|
{
|
|
kfree(tags->rqs);
|
|
tags->rqs = NULL;
|
|
kfree(tags->static_rqs);
|
|
tags->static_rqs = NULL;
|
|
|
|
blk_mq_free_tags(tags);
|
|
}
|
|
|
|
struct blk_mq_tags *blk_mq_alloc_rq_map(struct blk_mq_tag_set *set,
|
|
unsigned int hctx_idx,
|
|
unsigned int nr_tags,
|
|
unsigned int reserved_tags)
|
|
{
|
|
struct blk_mq_tags *tags;
|
|
int node;
|
|
|
|
node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx);
|
|
if (node == NUMA_NO_NODE)
|
|
node = set->numa_node;
|
|
|
|
tags = blk_mq_init_tags(nr_tags, reserved_tags, node,
|
|
BLK_MQ_FLAG_TO_ALLOC_POLICY(set->flags));
|
|
if (!tags)
|
|
return NULL;
|
|
|
|
tags->rqs = kzalloc_node(nr_tags * sizeof(struct request *),
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
|
|
node);
|
|
if (!tags->rqs) {
|
|
blk_mq_free_tags(tags);
|
|
return NULL;
|
|
}
|
|
|
|
tags->static_rqs = kzalloc_node(nr_tags * sizeof(struct request *),
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY,
|
|
node);
|
|
if (!tags->static_rqs) {
|
|
kfree(tags->rqs);
|
|
blk_mq_free_tags(tags);
|
|
return NULL;
|
|
}
|
|
|
|
return tags;
|
|
}
|
|
|
|
static size_t order_to_size(unsigned int order)
|
|
{
|
|
return (size_t)PAGE_SIZE << order;
|
|
}
|
|
|
|
int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
|
|
unsigned int hctx_idx, unsigned int depth)
|
|
{
|
|
unsigned int i, j, entries_per_page, max_order = 4;
|
|
size_t rq_size, left;
|
|
int node;
|
|
|
|
node = blk_mq_hw_queue_to_node(set->mq_map, hctx_idx);
|
|
if (node == NUMA_NO_NODE)
|
|
node = set->numa_node;
|
|
|
|
INIT_LIST_HEAD(&tags->page_list);
|
|
|
|
/*
|
|
* rq_size is the size of the request plus driver payload, rounded
|
|
* to the cacheline size
|
|
*/
|
|
rq_size = round_up(sizeof(struct request) + set->cmd_size,
|
|
cache_line_size());
|
|
left = rq_size * depth;
|
|
|
|
for (i = 0; i < depth; ) {
|
|
int this_order = max_order;
|
|
struct page *page;
|
|
int to_do;
|
|
void *p;
|
|
|
|
while (this_order && left < order_to_size(this_order - 1))
|
|
this_order--;
|
|
|
|
do {
|
|
page = alloc_pages_node(node,
|
|
GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY | __GFP_ZERO,
|
|
this_order);
|
|
if (page)
|
|
break;
|
|
if (!this_order--)
|
|
break;
|
|
if (order_to_size(this_order) < rq_size)
|
|
break;
|
|
} while (1);
|
|
|
|
if (!page)
|
|
goto fail;
|
|
|
|
page->private = this_order;
|
|
list_add_tail(&page->lru, &tags->page_list);
|
|
|
|
p = page_address(page);
|
|
/*
|
|
* Allow kmemleak to scan these pages as they contain pointers
|
|
* to additional allocations like via ops->init_request().
|
|
*/
|
|
kmemleak_alloc(p, order_to_size(this_order), 1, GFP_NOIO);
|
|
entries_per_page = order_to_size(this_order) / rq_size;
|
|
to_do = min(entries_per_page, depth - i);
|
|
left -= to_do * rq_size;
|
|
for (j = 0; j < to_do; j++) {
|
|
struct request *rq = p;
|
|
|
|
tags->static_rqs[i] = rq;
|
|
if (set->ops->init_request) {
|
|
if (set->ops->init_request(set->driver_data,
|
|
rq, hctx_idx, i,
|
|
node)) {
|
|
tags->static_rqs[i] = NULL;
|
|
goto fail;
|
|
}
|
|
}
|
|
|
|
p += rq_size;
|
|
i++;
|
|
}
|
|
}
|
|
return 0;
|
|
|
|
fail:
|
|
blk_mq_free_rqs(set, tags, hctx_idx);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* 'cpu' is going away. splice any existing rq_list entries from this
|
|
* software queue to the hw queue dispatch list, and ensure that it
|
|
* gets run.
|
|
*/
|
|
static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct blk_mq_ctx *ctx;
|
|
LIST_HEAD(tmp);
|
|
|
|
hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead);
|
|
ctx = __blk_mq_get_ctx(hctx->queue, cpu);
|
|
|
|
spin_lock(&ctx->lock);
|
|
if (!list_empty(&ctx->rq_list)) {
|
|
list_splice_init(&ctx->rq_list, &tmp);
|
|
blk_mq_hctx_clear_pending(hctx, ctx);
|
|
}
|
|
spin_unlock(&ctx->lock);
|
|
|
|
if (list_empty(&tmp))
|
|
return 0;
|
|
|
|
spin_lock(&hctx->lock);
|
|
list_splice_tail_init(&tmp, &hctx->dispatch);
|
|
spin_unlock(&hctx->lock);
|
|
|
|
blk_mq_run_hw_queue(hctx, true);
|
|
return 0;
|
|
}
|
|
|
|
static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD,
|
|
&hctx->cpuhp_dead);
|
|
}
|
|
|
|
/* hctx->ctxs will be freed in queue's release handler */
|
|
static void blk_mq_exit_hctx(struct request_queue *q,
|
|
struct blk_mq_tag_set *set,
|
|
struct blk_mq_hw_ctx *hctx, unsigned int hctx_idx)
|
|
{
|
|
unsigned flush_start_tag = set->queue_depth;
|
|
|
|
blk_mq_tag_idle(hctx);
|
|
|
|
if (set->ops->exit_request)
|
|
set->ops->exit_request(set->driver_data,
|
|
hctx->fq->flush_rq, hctx_idx,
|
|
flush_start_tag + hctx_idx);
|
|
|
|
if (set->ops->exit_hctx)
|
|
set->ops->exit_hctx(hctx, hctx_idx);
|
|
|
|
if (hctx->flags & BLK_MQ_F_BLOCKING)
|
|
cleanup_srcu_struct(&hctx->queue_rq_srcu);
|
|
|
|
blk_mq_remove_cpuhp(hctx);
|
|
blk_free_flush_queue(hctx->fq);
|
|
sbitmap_free(&hctx->ctx_map);
|
|
}
|
|
|
|
static void blk_mq_exit_hw_queues(struct request_queue *q,
|
|
struct blk_mq_tag_set *set, int nr_queue)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
unsigned int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (i == nr_queue)
|
|
break;
|
|
blk_mq_exit_hctx(q, set, hctx, i);
|
|
}
|
|
}
|
|
|
|
static int blk_mq_init_hctx(struct request_queue *q,
|
|
struct blk_mq_tag_set *set,
|
|
struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
|
|
{
|
|
int node;
|
|
unsigned flush_start_tag = set->queue_depth;
|
|
|
|
node = hctx->numa_node;
|
|
if (node == NUMA_NO_NODE)
|
|
node = hctx->numa_node = set->numa_node;
|
|
|
|
INIT_WORK(&hctx->run_work, blk_mq_run_work_fn);
|
|
INIT_DELAYED_WORK(&hctx->delay_work, blk_mq_delay_work_fn);
|
|
spin_lock_init(&hctx->lock);
|
|
INIT_LIST_HEAD(&hctx->dispatch);
|
|
hctx->queue = q;
|
|
hctx->queue_num = hctx_idx;
|
|
hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED;
|
|
|
|
cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);
|
|
|
|
hctx->tags = set->tags[hctx_idx];
|
|
|
|
/*
|
|
* Allocate space for all possible cpus to avoid allocation at
|
|
* runtime
|
|
*/
|
|
hctx->ctxs = kmalloc_node(nr_cpu_ids * sizeof(void *),
|
|
GFP_KERNEL, node);
|
|
if (!hctx->ctxs)
|
|
goto unregister_cpu_notifier;
|
|
|
|
if (sbitmap_init_node(&hctx->ctx_map, nr_cpu_ids, ilog2(8), GFP_KERNEL,
|
|
node))
|
|
goto free_ctxs;
|
|
|
|
hctx->nr_ctx = 0;
|
|
|
|
if (set->ops->init_hctx &&
|
|
set->ops->init_hctx(hctx, set->driver_data, hctx_idx))
|
|
goto free_bitmap;
|
|
|
|
hctx->fq = blk_alloc_flush_queue(q, hctx->numa_node, set->cmd_size);
|
|
if (!hctx->fq)
|
|
goto exit_hctx;
|
|
|
|
if (set->ops->init_request &&
|
|
set->ops->init_request(set->driver_data,
|
|
hctx->fq->flush_rq, hctx_idx,
|
|
flush_start_tag + hctx_idx, node))
|
|
goto free_fq;
|
|
|
|
if (hctx->flags & BLK_MQ_F_BLOCKING)
|
|
init_srcu_struct(&hctx->queue_rq_srcu);
|
|
|
|
return 0;
|
|
|
|
free_fq:
|
|
kfree(hctx->fq);
|
|
exit_hctx:
|
|
if (set->ops->exit_hctx)
|
|
set->ops->exit_hctx(hctx, hctx_idx);
|
|
free_bitmap:
|
|
sbitmap_free(&hctx->ctx_map);
|
|
free_ctxs:
|
|
kfree(hctx->ctxs);
|
|
unregister_cpu_notifier:
|
|
blk_mq_remove_cpuhp(hctx);
|
|
return -1;
|
|
}
|
|
|
|
static void blk_mq_init_cpu_queues(struct request_queue *q,
|
|
unsigned int nr_hw_queues)
|
|
{
|
|
unsigned int i;
|
|
|
|
for_each_possible_cpu(i) {
|
|
struct blk_mq_ctx *__ctx = per_cpu_ptr(q->queue_ctx, i);
|
|
struct blk_mq_hw_ctx *hctx;
|
|
|
|
__ctx->cpu = i;
|
|
spin_lock_init(&__ctx->lock);
|
|
INIT_LIST_HEAD(&__ctx->rq_list);
|
|
__ctx->queue = q;
|
|
blk_stat_init(&__ctx->stat[BLK_STAT_READ]);
|
|
blk_stat_init(&__ctx->stat[BLK_STAT_WRITE]);
|
|
|
|
/* If the cpu isn't online, the cpu is mapped to first hctx */
|
|
if (!cpu_online(i))
|
|
continue;
|
|
|
|
hctx = blk_mq_map_queue(q, i);
|
|
|
|
/*
|
|
* Set local node, IFF we have more than one hw queue. If
|
|
* not, we remain on the home node of the device
|
|
*/
|
|
if (nr_hw_queues > 1 && hctx->numa_node == NUMA_NO_NODE)
|
|
hctx->numa_node = local_memory_node(cpu_to_node(i));
|
|
}
|
|
}
|
|
|
|
static bool __blk_mq_alloc_rq_map(struct blk_mq_tag_set *set, int hctx_idx)
|
|
{
|
|
int ret = 0;
|
|
|
|
set->tags[hctx_idx] = blk_mq_alloc_rq_map(set, hctx_idx,
|
|
set->queue_depth, set->reserved_tags);
|
|
if (!set->tags[hctx_idx])
|
|
return false;
|
|
|
|
ret = blk_mq_alloc_rqs(set, set->tags[hctx_idx], hctx_idx,
|
|
set->queue_depth);
|
|
if (!ret)
|
|
return true;
|
|
|
|
blk_mq_free_rq_map(set->tags[hctx_idx]);
|
|
set->tags[hctx_idx] = NULL;
|
|
return false;
|
|
}
|
|
|
|
static void blk_mq_free_map_and_requests(struct blk_mq_tag_set *set,
|
|
unsigned int hctx_idx)
|
|
{
|
|
if (set->tags[hctx_idx]) {
|
|
blk_mq_free_rqs(set, set->tags[hctx_idx], hctx_idx);
|
|
blk_mq_free_rq_map(set->tags[hctx_idx]);
|
|
set->tags[hctx_idx] = NULL;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_map_swqueue(struct request_queue *q,
|
|
const struct cpumask *online_mask)
|
|
{
|
|
unsigned int i, hctx_idx;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct blk_mq_ctx *ctx;
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
/*
|
|
* Avoid others reading imcomplete hctx->cpumask through sysfs
|
|
*/
|
|
mutex_lock(&q->sysfs_lock);
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
cpumask_clear(hctx->cpumask);
|
|
hctx->nr_ctx = 0;
|
|
}
|
|
|
|
/*
|
|
* Map software to hardware queues
|
|
*/
|
|
for_each_possible_cpu(i) {
|
|
/* If the cpu isn't online, the cpu is mapped to first hctx */
|
|
if (!cpumask_test_cpu(i, online_mask))
|
|
continue;
|
|
|
|
hctx_idx = q->mq_map[i];
|
|
/* unmapped hw queue can be remapped after CPU topo changed */
|
|
if (!set->tags[hctx_idx] &&
|
|
!__blk_mq_alloc_rq_map(set, hctx_idx)) {
|
|
/*
|
|
* If tags initialization fail for some hctx,
|
|
* that hctx won't be brought online. In this
|
|
* case, remap the current ctx to hctx[0] which
|
|
* is guaranteed to always have tags allocated
|
|
*/
|
|
q->mq_map[i] = 0;
|
|
}
|
|
|
|
ctx = per_cpu_ptr(q->queue_ctx, i);
|
|
hctx = blk_mq_map_queue(q, i);
|
|
|
|
cpumask_set_cpu(i, hctx->cpumask);
|
|
ctx->index_hw = hctx->nr_ctx;
|
|
hctx->ctxs[hctx->nr_ctx++] = ctx;
|
|
}
|
|
|
|
mutex_unlock(&q->sysfs_lock);
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
/*
|
|
* If no software queues are mapped to this hardware queue,
|
|
* disable it and free the request entries.
|
|
*/
|
|
if (!hctx->nr_ctx) {
|
|
/* Never unmap queue 0. We need it as a
|
|
* fallback in case of a new remap fails
|
|
* allocation
|
|
*/
|
|
if (i && set->tags[i])
|
|
blk_mq_free_map_and_requests(set, i);
|
|
|
|
hctx->tags = NULL;
|
|
continue;
|
|
}
|
|
|
|
hctx->tags = set->tags[i];
|
|
WARN_ON(!hctx->tags);
|
|
|
|
/*
|
|
* Set the map size to the number of mapped software queues.
|
|
* This is more accurate and more efficient than looping
|
|
* over all possibly mapped software queues.
|
|
*/
|
|
sbitmap_resize(&hctx->ctx_map, hctx->nr_ctx);
|
|
|
|
/*
|
|
* Initialize batch roundrobin counts
|
|
*/
|
|
hctx->next_cpu = cpumask_first(hctx->cpumask);
|
|
hctx->next_cpu_batch = BLK_MQ_CPU_WORK_BATCH;
|
|
}
|
|
}
|
|
|
|
static void queue_set_hctx_shared(struct request_queue *q, bool shared)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (shared)
|
|
hctx->flags |= BLK_MQ_F_TAG_SHARED;
|
|
else
|
|
hctx->flags &= ~BLK_MQ_F_TAG_SHARED;
|
|
}
|
|
}
|
|
|
|
static void blk_mq_update_tag_set_depth(struct blk_mq_tag_set *set, bool shared)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
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_init(&q->tag_set_list);
|
|
if (list_is_singular(&set->tag_list)) {
|
|
/* just transitioned to unshared */
|
|
set->flags &= ~BLK_MQ_F_TAG_SHARED;
|
|
/* update existing queue */
|
|
blk_mq_update_tag_set_depth(set, false);
|
|
}
|
|
mutex_unlock(&set->tag_list_lock);
|
|
}
|
|
|
|
static void blk_mq_add_queue_tag_set(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
q->tag_set = set;
|
|
|
|
mutex_lock(&set->tag_list_lock);
|
|
|
|
/* Check to see if we're transitioning to shared (from 1 to 2 queues). */
|
|
if (!list_empty(&set->tag_list) && !(set->flags & BLK_MQ_F_TAG_SHARED)) {
|
|
set->flags |= BLK_MQ_F_TAG_SHARED;
|
|
/* update existing queue */
|
|
blk_mq_update_tag_set_depth(set, true);
|
|
}
|
|
if (set->flags & BLK_MQ_F_TAG_SHARED)
|
|
queue_set_hctx_shared(q, true);
|
|
list_add_tail(&q->tag_set_list, &set->tag_list);
|
|
|
|
mutex_unlock(&set->tag_list_lock);
|
|
}
|
|
|
|
/*
|
|
* It is the actual release handler for mq, but we do it from
|
|
* request queue's release handler for avoiding use-after-free
|
|
* and headache because q->mq_kobj shouldn't have been introduced,
|
|
* but we can't group ctx/kctx kobj without it.
|
|
*/
|
|
void blk_mq_release(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
unsigned int i;
|
|
|
|
blk_mq_sched_teardown(q);
|
|
|
|
/* hctx kobj stays in hctx */
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
if (!hctx)
|
|
continue;
|
|
kobject_put(&hctx->kobj);
|
|
}
|
|
|
|
q->mq_map = NULL;
|
|
|
|
kfree(q->queue_hw_ctx);
|
|
|
|
/*
|
|
* release .mq_kobj and sw queue's kobject now because
|
|
* both share lifetime with request queue.
|
|
*/
|
|
blk_mq_sysfs_deinit(q);
|
|
|
|
free_percpu(q->queue_ctx);
|
|
}
|
|
|
|
struct request_queue *blk_mq_init_queue(struct blk_mq_tag_set *set)
|
|
{
|
|
struct request_queue *uninit_q, *q;
|
|
|
|
uninit_q = blk_alloc_queue_node(GFP_KERNEL, set->numa_node);
|
|
if (!uninit_q)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
q = blk_mq_init_allocated_queue(set, uninit_q);
|
|
if (IS_ERR(q))
|
|
blk_cleanup_queue(uninit_q);
|
|
|
|
return q;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_init_queue);
|
|
|
|
static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
int i, j;
|
|
struct blk_mq_hw_ctx **hctxs = q->queue_hw_ctx;
|
|
|
|
blk_mq_sysfs_unregister(q);
|
|
for (i = 0; i < set->nr_hw_queues; i++) {
|
|
int node;
|
|
|
|
if (hctxs[i])
|
|
continue;
|
|
|
|
node = blk_mq_hw_queue_to_node(q->mq_map, i);
|
|
hctxs[i] = kzalloc_node(sizeof(struct blk_mq_hw_ctx),
|
|
GFP_KERNEL, node);
|
|
if (!hctxs[i])
|
|
break;
|
|
|
|
if (!zalloc_cpumask_var_node(&hctxs[i]->cpumask, GFP_KERNEL,
|
|
node)) {
|
|
kfree(hctxs[i]);
|
|
hctxs[i] = NULL;
|
|
break;
|
|
}
|
|
|
|
atomic_set(&hctxs[i]->nr_active, 0);
|
|
hctxs[i]->numa_node = node;
|
|
hctxs[i]->queue_num = i;
|
|
|
|
if (blk_mq_init_hctx(q, set, hctxs[i], i)) {
|
|
free_cpumask_var(hctxs[i]->cpumask);
|
|
kfree(hctxs[i]);
|
|
hctxs[i] = NULL;
|
|
break;
|
|
}
|
|
blk_mq_hctx_kobj_init(hctxs[i]);
|
|
}
|
|
for (j = i; j < q->nr_hw_queues; j++) {
|
|
struct blk_mq_hw_ctx *hctx = hctxs[j];
|
|
|
|
if (hctx) {
|
|
if (hctx->tags)
|
|
blk_mq_free_map_and_requests(set, j);
|
|
blk_mq_exit_hctx(q, set, hctx, j);
|
|
kobject_put(&hctx->kobj);
|
|
hctxs[j] = NULL;
|
|
|
|
}
|
|
}
|
|
q->nr_hw_queues = i;
|
|
blk_mq_sysfs_register(q);
|
|
}
|
|
|
|
struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set,
|
|
struct request_queue *q)
|
|
{
|
|
/* mark the queue as mq asap */
|
|
q->mq_ops = set->ops;
|
|
|
|
q->queue_ctx = alloc_percpu(struct blk_mq_ctx);
|
|
if (!q->queue_ctx)
|
|
goto err_exit;
|
|
|
|
/* init q->mq_kobj and sw queues' kobjects */
|
|
blk_mq_sysfs_init(q);
|
|
|
|
q->queue_hw_ctx = kzalloc_node(nr_cpu_ids * sizeof(*(q->queue_hw_ctx)),
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!q->queue_hw_ctx)
|
|
goto err_percpu;
|
|
|
|
q->mq_map = set->mq_map;
|
|
|
|
blk_mq_realloc_hw_ctxs(set, q);
|
|
if (!q->nr_hw_queues)
|
|
goto err_hctxs;
|
|
|
|
INIT_WORK(&q->timeout_work, blk_mq_timeout_work);
|
|
blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ);
|
|
|
|
q->nr_queues = nr_cpu_ids;
|
|
|
|
q->queue_flags |= QUEUE_FLAG_MQ_DEFAULT;
|
|
|
|
if (!(set->flags & BLK_MQ_F_SG_MERGE))
|
|
q->queue_flags |= 1 << QUEUE_FLAG_NO_SG_MERGE;
|
|
|
|
q->sg_reserved_size = INT_MAX;
|
|
|
|
INIT_DELAYED_WORK(&q->requeue_work, blk_mq_requeue_work);
|
|
INIT_LIST_HEAD(&q->requeue_list);
|
|
spin_lock_init(&q->requeue_lock);
|
|
|
|
if (q->nr_hw_queues > 1)
|
|
blk_queue_make_request(q, blk_mq_make_request);
|
|
else
|
|
blk_queue_make_request(q, blk_sq_make_request);
|
|
|
|
/*
|
|
* Do this after blk_queue_make_request() overrides it...
|
|
*/
|
|
q->nr_requests = set->queue_depth;
|
|
|
|
/*
|
|
* Default to classic polling
|
|
*/
|
|
q->poll_nsec = -1;
|
|
|
|
if (set->ops->complete)
|
|
blk_queue_softirq_done(q, set->ops->complete);
|
|
|
|
blk_mq_init_cpu_queues(q, set->nr_hw_queues);
|
|
|
|
get_online_cpus();
|
|
mutex_lock(&all_q_mutex);
|
|
|
|
list_add_tail(&q->all_q_node, &all_q_list);
|
|
blk_mq_add_queue_tag_set(set, q);
|
|
blk_mq_map_swqueue(q, cpu_online_mask);
|
|
|
|
mutex_unlock(&all_q_mutex);
|
|
put_online_cpus();
|
|
|
|
if (!(set->flags & BLK_MQ_F_NO_SCHED)) {
|
|
int ret;
|
|
|
|
ret = blk_mq_sched_init(q);
|
|
if (ret)
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
return q;
|
|
|
|
err_hctxs:
|
|
kfree(q->queue_hw_ctx);
|
|
err_percpu:
|
|
free_percpu(q->queue_ctx);
|
|
err_exit:
|
|
q->mq_ops = NULL;
|
|
return ERR_PTR(-ENOMEM);
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_init_allocated_queue);
|
|
|
|
void blk_mq_free_queue(struct request_queue *q)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
|
|
mutex_lock(&all_q_mutex);
|
|
list_del_init(&q->all_q_node);
|
|
mutex_unlock(&all_q_mutex);
|
|
|
|
wbt_exit(q);
|
|
|
|
blk_mq_del_queue_tag_set(q);
|
|
|
|
blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
|
|
}
|
|
|
|
/* Basically redo blk_mq_init_queue with queue frozen */
|
|
static void blk_mq_queue_reinit(struct request_queue *q,
|
|
const struct cpumask *online_mask)
|
|
{
|
|
WARN_ON_ONCE(!atomic_read(&q->mq_freeze_depth));
|
|
|
|
blk_mq_sysfs_unregister(q);
|
|
|
|
/*
|
|
* redo blk_mq_init_cpu_queues and blk_mq_init_hw_queues. FIXME: maybe
|
|
* we should change hctx numa_node according to new topology (this
|
|
* involves free and re-allocate memory, worthy doing?)
|
|
*/
|
|
|
|
blk_mq_map_swqueue(q, online_mask);
|
|
|
|
blk_mq_sysfs_register(q);
|
|
}
|
|
|
|
/*
|
|
* New online cpumask which is going to be set in this hotplug event.
|
|
* Declare this cpumasks as global as cpu-hotplug operation is invoked
|
|
* one-by-one and dynamically allocating this could result in a failure.
|
|
*/
|
|
static struct cpumask cpuhp_online_new;
|
|
|
|
static void blk_mq_queue_reinit_work(void)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
mutex_lock(&all_q_mutex);
|
|
/*
|
|
* We need to freeze and reinit all existing queues. Freezing
|
|
* involves synchronous wait for an RCU grace period and doing it
|
|
* one by one may take a long time. Start freezing all queues in
|
|
* one swoop and then wait for the completions so that freezing can
|
|
* take place in parallel.
|
|
*/
|
|
list_for_each_entry(q, &all_q_list, all_q_node)
|
|
blk_mq_freeze_queue_start(q);
|
|
list_for_each_entry(q, &all_q_list, all_q_node)
|
|
blk_mq_freeze_queue_wait(q);
|
|
|
|
list_for_each_entry(q, &all_q_list, all_q_node)
|
|
blk_mq_queue_reinit(q, &cpuhp_online_new);
|
|
|
|
list_for_each_entry(q, &all_q_list, all_q_node)
|
|
blk_mq_unfreeze_queue(q);
|
|
|
|
mutex_unlock(&all_q_mutex);
|
|
}
|
|
|
|
static int blk_mq_queue_reinit_dead(unsigned int cpu)
|
|
{
|
|
cpumask_copy(&cpuhp_online_new, cpu_online_mask);
|
|
blk_mq_queue_reinit_work();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Before hotadded cpu starts handling requests, new mappings must be
|
|
* established. Otherwise, these requests in hw queue might never be
|
|
* dispatched.
|
|
*
|
|
* For example, there is a single hw queue (hctx) and two CPU queues (ctx0
|
|
* for CPU0, and ctx1 for CPU1).
|
|
*
|
|
* Now CPU1 is just onlined and a request is inserted into ctx1->rq_list
|
|
* and set bit0 in pending bitmap as ctx1->index_hw is still zero.
|
|
*
|
|
* And then while running hw queue, blk_mq_flush_busy_ctxs() finds bit0 is set
|
|
* in pending bitmap and tries to retrieve requests in hctx->ctxs[0]->rq_list.
|
|
* But htx->ctxs[0] is a pointer to ctx0, so the request in ctx1->rq_list is
|
|
* ignored.
|
|
*/
|
|
static int blk_mq_queue_reinit_prepare(unsigned int cpu)
|
|
{
|
|
cpumask_copy(&cpuhp_online_new, cpu_online_mask);
|
|
cpumask_set_cpu(cpu, &cpuhp_online_new);
|
|
blk_mq_queue_reinit_work();
|
|
return 0;
|
|
}
|
|
|
|
static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < set->nr_hw_queues; i++)
|
|
if (!__blk_mq_alloc_rq_map(set, i))
|
|
goto out_unwind;
|
|
|
|
return 0;
|
|
|
|
out_unwind:
|
|
while (--i >= 0)
|
|
blk_mq_free_rq_map(set->tags[i]);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* Allocate the request maps associated with this tag_set. Note that this
|
|
* may reduce the depth asked for, if memory is tight. set->queue_depth
|
|
* will be updated to reflect the allocated depth.
|
|
*/
|
|
static int blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set)
|
|
{
|
|
unsigned int depth;
|
|
int err;
|
|
|
|
depth = set->queue_depth;
|
|
do {
|
|
err = __blk_mq_alloc_rq_maps(set);
|
|
if (!err)
|
|
break;
|
|
|
|
set->queue_depth >>= 1;
|
|
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN) {
|
|
err = -ENOMEM;
|
|
break;
|
|
}
|
|
} while (set->queue_depth);
|
|
|
|
if (!set->queue_depth || err) {
|
|
pr_err("blk-mq: failed to allocate request map\n");
|
|
return -ENOMEM;
|
|
}
|
|
|
|
if (depth != set->queue_depth)
|
|
pr_info("blk-mq: reduced tag depth (%u -> %u)\n",
|
|
depth, set->queue_depth);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Alloc a tag set to be associated with one or more request queues.
|
|
* May fail with EINVAL for various error conditions. May adjust the
|
|
* requested depth down, if if it too large. In that case, the set
|
|
* value will be stored in set->queue_depth.
|
|
*/
|
|
int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
|
|
{
|
|
int ret;
|
|
|
|
BUILD_BUG_ON(BLK_MQ_MAX_DEPTH > 1 << BLK_MQ_UNIQUE_TAG_BITS);
|
|
|
|
if (!set->nr_hw_queues)
|
|
return -EINVAL;
|
|
if (!set->queue_depth)
|
|
return -EINVAL;
|
|
if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
|
|
return -EINVAL;
|
|
|
|
if (!set->ops->queue_rq)
|
|
return -EINVAL;
|
|
|
|
if (set->queue_depth > BLK_MQ_MAX_DEPTH) {
|
|
pr_info("blk-mq: reduced tag depth to %u\n",
|
|
BLK_MQ_MAX_DEPTH);
|
|
set->queue_depth = BLK_MQ_MAX_DEPTH;
|
|
}
|
|
|
|
/*
|
|
* If a crashdump is active, then we are potentially in a very
|
|
* memory constrained environment. Limit us to 1 queue and
|
|
* 64 tags to prevent using too much memory.
|
|
*/
|
|
if (is_kdump_kernel()) {
|
|
set->nr_hw_queues = 1;
|
|
set->queue_depth = min(64U, set->queue_depth);
|
|
}
|
|
/*
|
|
* There is no use for more h/w queues than cpus.
|
|
*/
|
|
if (set->nr_hw_queues > nr_cpu_ids)
|
|
set->nr_hw_queues = nr_cpu_ids;
|
|
|
|
set->tags = kzalloc_node(nr_cpu_ids * sizeof(struct blk_mq_tags *),
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!set->tags)
|
|
return -ENOMEM;
|
|
|
|
ret = -ENOMEM;
|
|
set->mq_map = kzalloc_node(sizeof(*set->mq_map) * nr_cpu_ids,
|
|
GFP_KERNEL, set->numa_node);
|
|
if (!set->mq_map)
|
|
goto out_free_tags;
|
|
|
|
if (set->ops->map_queues)
|
|
ret = set->ops->map_queues(set);
|
|
else
|
|
ret = blk_mq_map_queues(set);
|
|
if (ret)
|
|
goto out_free_mq_map;
|
|
|
|
ret = blk_mq_alloc_rq_maps(set);
|
|
if (ret)
|
|
goto out_free_mq_map;
|
|
|
|
mutex_init(&set->tag_list_lock);
|
|
INIT_LIST_HEAD(&set->tag_list);
|
|
|
|
return 0;
|
|
|
|
out_free_mq_map:
|
|
kfree(set->mq_map);
|
|
set->mq_map = NULL;
|
|
out_free_tags:
|
|
kfree(set->tags);
|
|
set->tags = NULL;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_alloc_tag_set);
|
|
|
|
void blk_mq_free_tag_set(struct blk_mq_tag_set *set)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < nr_cpu_ids; i++)
|
|
blk_mq_free_map_and_requests(set, i);
|
|
|
|
kfree(set->mq_map);
|
|
set->mq_map = NULL;
|
|
|
|
kfree(set->tags);
|
|
set->tags = NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_mq_free_tag_set);
|
|
|
|
int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr)
|
|
{
|
|
struct blk_mq_tag_set *set = q->tag_set;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i, ret;
|
|
|
|
if (!set)
|
|
return -EINVAL;
|
|
|
|
blk_mq_freeze_queue(q);
|
|
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,
|
|
min(nr, set->queue_depth),
|
|
false);
|
|
} else {
|
|
ret = blk_mq_tag_update_depth(hctx, &hctx->sched_tags,
|
|
nr, true);
|
|
}
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
if (!ret)
|
|
q->nr_requests = nr;
|
|
|
|
blk_mq_unfreeze_queue(q);
|
|
blk_mq_start_stopped_hw_queues(q, true);
|
|
|
|
return ret;
|
|
}
|
|
|
|
void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues)
|
|
{
|
|
struct request_queue *q;
|
|
|
|
if (nr_hw_queues > nr_cpu_ids)
|
|
nr_hw_queues = nr_cpu_ids;
|
|
if (nr_hw_queues < 1 || nr_hw_queues == set->nr_hw_queues)
|
|
return;
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
blk_mq_freeze_queue(q);
|
|
|
|
set->nr_hw_queues = nr_hw_queues;
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list) {
|
|
blk_mq_realloc_hw_ctxs(set, q);
|
|
|
|
/*
|
|
* Manually set the make_request_fn as blk_queue_make_request
|
|
* resets a lot of the queue settings.
|
|
*/
|
|
if (q->nr_hw_queues > 1)
|
|
q->make_request_fn = blk_mq_make_request;
|
|
else
|
|
q->make_request_fn = blk_sq_make_request;
|
|
|
|
blk_mq_queue_reinit(q, cpu_online_mask);
|
|
}
|
|
|
|
list_for_each_entry(q, &set->tag_list, tag_set_list)
|
|
blk_mq_unfreeze_queue(q);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues);
|
|
|
|
static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
|
|
struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
struct blk_rq_stat stat[2];
|
|
unsigned long ret = 0;
|
|
|
|
/*
|
|
* If stats collection isn't on, don't sleep but turn it on for
|
|
* future users
|
|
*/
|
|
if (!blk_stat_enable(q))
|
|
return 0;
|
|
|
|
/*
|
|
* We don't have to do this once per IO, should optimize this
|
|
* to just use the current window of stats until it changes
|
|
*/
|
|
memset(&stat, 0, sizeof(stat));
|
|
blk_hctx_stat_get(hctx, stat);
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
if (req_op(rq) == REQ_OP_READ && stat[BLK_STAT_READ].nr_samples)
|
|
ret = (stat[BLK_STAT_READ].mean + 1) / 2;
|
|
else if (req_op(rq) == REQ_OP_WRITE && stat[BLK_STAT_WRITE].nr_samples)
|
|
ret = (stat[BLK_STAT_WRITE].mean + 1) / 2;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
|
|
struct blk_mq_hw_ctx *hctx,
|
|
struct request *rq)
|
|
{
|
|
struct hrtimer_sleeper hs;
|
|
enum hrtimer_mode mode;
|
|
unsigned int nsecs;
|
|
ktime_t kt;
|
|
|
|
if (test_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags))
|
|
return false;
|
|
|
|
/*
|
|
* poll_nsec can be:
|
|
*
|
|
* -1: don't ever hybrid sleep
|
|
* 0: use half of prev avg
|
|
* >0: use this specific value
|
|
*/
|
|
if (q->poll_nsec == -1)
|
|
return false;
|
|
else if (q->poll_nsec > 0)
|
|
nsecs = q->poll_nsec;
|
|
else
|
|
nsecs = blk_mq_poll_nsecs(q, hctx, rq);
|
|
|
|
if (!nsecs)
|
|
return false;
|
|
|
|
set_bit(REQ_ATOM_POLL_SLEPT, &rq->atomic_flags);
|
|
|
|
/*
|
|
* This will be replaced with the stats tracking code, using
|
|
* 'avg_completion_time / 2' as the pre-sleep target.
|
|
*/
|
|
kt = nsecs;
|
|
|
|
mode = HRTIMER_MODE_REL;
|
|
hrtimer_init_on_stack(&hs.timer, CLOCK_MONOTONIC, mode);
|
|
hrtimer_set_expires(&hs.timer, kt);
|
|
|
|
hrtimer_init_sleeper(&hs, current);
|
|
do {
|
|
if (test_bit(REQ_ATOM_COMPLETE, &rq->atomic_flags))
|
|
break;
|
|
set_current_state(TASK_UNINTERRUPTIBLE);
|
|
hrtimer_start_expires(&hs.timer, mode);
|
|
if (hs.task)
|
|
io_schedule();
|
|
hrtimer_cancel(&hs.timer);
|
|
mode = HRTIMER_MODE_ABS;
|
|
} while (hs.task && !signal_pending(current));
|
|
|
|
__set_current_state(TASK_RUNNING);
|
|
destroy_hrtimer_on_stack(&hs.timer);
|
|
return true;
|
|
}
|
|
|
|
static bool __blk_mq_poll(struct blk_mq_hw_ctx *hctx, struct request *rq)
|
|
{
|
|
struct request_queue *q = hctx->queue;
|
|
long state;
|
|
|
|
/*
|
|
* If we sleep, have the caller restart the poll loop to reset
|
|
* the state. Like for the other success return cases, the
|
|
* caller is responsible for checking if the IO completed. If
|
|
* the IO isn't complete, we'll get called again and will go
|
|
* straight to the busy poll loop.
|
|
*/
|
|
if (blk_mq_poll_hybrid_sleep(q, hctx, rq))
|
|
return true;
|
|
|
|
hctx->poll_considered++;
|
|
|
|
state = current->state;
|
|
while (!need_resched()) {
|
|
int ret;
|
|
|
|
hctx->poll_invoked++;
|
|
|
|
ret = q->mq_ops->poll(hctx, rq->tag);
|
|
if (ret > 0) {
|
|
hctx->poll_success++;
|
|
set_current_state(TASK_RUNNING);
|
|
return true;
|
|
}
|
|
|
|
if (signal_pending_state(state, current))
|
|
set_current_state(TASK_RUNNING);
|
|
|
|
if (current->state == TASK_RUNNING)
|
|
return true;
|
|
if (ret < 0)
|
|
break;
|
|
cpu_relax();
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
bool blk_mq_poll(struct request_queue *q, blk_qc_t cookie)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct blk_plug *plug;
|
|
struct request *rq;
|
|
|
|
if (!q->mq_ops || !q->mq_ops->poll || !blk_qc_t_valid(cookie) ||
|
|
!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
|
|
return false;
|
|
|
|
plug = current->plug;
|
|
if (plug)
|
|
blk_flush_plug_list(plug, false);
|
|
|
|
hctx = q->queue_hw_ctx[blk_qc_t_to_queue_num(cookie)];
|
|
if (!blk_qc_t_is_internal(cookie))
|
|
rq = blk_mq_tag_to_rq(hctx->tags, blk_qc_t_to_tag(cookie));
|
|
else
|
|
rq = blk_mq_tag_to_rq(hctx->sched_tags, blk_qc_t_to_tag(cookie));
|
|
|
|
return __blk_mq_poll(hctx, rq);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_mq_poll);
|
|
|
|
void blk_mq_disable_hotplug(void)
|
|
{
|
|
mutex_lock(&all_q_mutex);
|
|
}
|
|
|
|
void blk_mq_enable_hotplug(void)
|
|
{
|
|
mutex_unlock(&all_q_mutex);
|
|
}
|
|
|
|
static int __init blk_mq_init(void)
|
|
{
|
|
cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
|
|
blk_mq_hctx_notify_dead);
|
|
|
|
cpuhp_setup_state_nocalls(CPUHP_BLK_MQ_PREPARE, "block/mq:prepare",
|
|
blk_mq_queue_reinit_prepare,
|
|
blk_mq_queue_reinit_dead);
|
|
return 0;
|
|
}
|
|
subsys_initcall(blk_mq_init);
|