block: drop queue lock before calling __blk_run_queue() for kblockd punt (99e22598) · Commits · 戴 / test

block/blk-core.c

+25 −8

Original line number	Diff line number	Diff line
		@@ -295,7 +295,8 @@ EXPORT_SYMBOL(blk_sync_queue);
		*
		* Description:
		* See @blk_run_queue. This variant must be called with the queue lock
		* held and interrupts disabled.
		* held and interrupts disabled. If force_kblockd is true, then it is
		* safe to call this without holding the queue lock.
		*
		*/
		void __blk_run_queue(struct request_queue *q, bool force_kblockd)
		@@ -2671,9 +2672,23 @@ static int plug_rq_cmp(void priv, struct list_head a, struct list_head *b)
		*/
		static void queue_unplugged(struct request_queue *q, unsigned int depth,
		bool from_schedule)
		__releases(q->queue_lock)
		{
		trace_block_unplug(q, depth, !from_schedule);
		__blk_run_queue(q, from_schedule);

		/*
		* If we are punting this to kblockd, then we can safely drop
		* the queue_lock before waking kblockd (which needs to take
		* this lock).
		*/
		if (from_schedule) {
		spin_unlock(q->queue_lock);
		__blk_run_queue(q, true);
		} else {
		__blk_run_queue(q, false);
		spin_unlock(q->queue_lock);
		}

		}

		static void flush_plug_callbacks(struct blk_plug *plug)
		@@ -2729,10 +2744,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
		BUG_ON(!(rq->cmd_flags & REQ_ON_PLUG));
		BUG_ON(!rq->q);
		if (rq->q != q) {
		if (q) {
		/*
		* This drops the queue lock
		*/
		if (q)
		queue_unplugged(q, depth, from_schedule);
		spin_unlock(q->queue_lock);
		}
		q = rq->q;
		depth = 0;
		spin_lock(q->queue_lock);
		@@ -2750,10 +2766,11 @@ void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
		depth++;
		}

		if (q) {
		/*
		* This drops the queue lock
		*/
		if (q)
		queue_unplugged(q, depth, from_schedule);
		spin_unlock(q->queue_lock);
		}

		local_irq_restore(flags);
		}

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