Commit 41adf531 authored by Ming Lei's avatar Ming Lei Committed by Jens Axboe
Browse files

blk-mq: don't run might_sleep() if the operation needn't blocking 



The operation protected via blk_mq_run_dispatch_ops() in blk_mq_run_hw_queue
won't sleep, so don't run might_sleep() for it.

Reported-and-tested-by: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 4cafe86c

block/blk-mq.c

+1 −1
Original line number Diff line number Diff line
@@ -2048,7 +2048,7 @@ void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) 
	 * And queue will be rerun in blk_mq_unquiesce_queue() if it is

	 * quiesced.

	 */

	blk_mq_run_dispatch_ops(hctx->queue,

	__blk_mq_run_dispatch_ops(hctx->queue, false,

		need_run = !blk_queue_quiesced(hctx->queue) &&

		blk_mq_hctx_has_pending(hctx));

block/blk-mq.h

+5 −2
Original line number Diff line number Diff line
@@ -375,7 +375,7 @@ static inline bool hctx_may_queue(struct blk_mq_hw_ctx *hctx, 
}



/* run the code block in @dispatch_ops with rcu/srcu read lock held */

#define blk_mq_run_dispatch_ops(q, dispatch_ops)		\

#define __blk_mq_run_dispatch_ops(q, check_sleep, dispatch_ops)	\

do {								\

	if (!blk_queue_has_srcu(q)) {				\

		rcu_read_lock();				\
@@ -384,11 +384,14 @@ do { \ 
	} else {						\

		int srcu_idx;					\

								\

		might_sleep();					\

		might_sleep_if(check_sleep);			\

		srcu_idx = srcu_read_lock((q)->srcu);		\

		(dispatch_ops);					\

		srcu_read_unlock((q)->srcu, srcu_idx);		\

	}							\

} while (0)



#define blk_mq_run_dispatch_ops(q, dispatch_ops)		\

	__blk_mq_run_dispatch_ops(q, true, dispatch_ops)	\



#endif