Commit 3f0bea9f authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

blk-mq-debugfs: factor out a helper to register debugfs for all rq_qos 



There is already a helper blk_mq_debugfs_register_rqos() to register
one rqos, however this helper is called synchronously when the rqos is
created with queue frozen.

Prepare to fix possible deadlock to create blk-mq debugfs entries while
queue is still frozen.

Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Reviewed-by: default avatarNilay Shroff <nilay@linux.ibm.com>
Signed-off-by: default avatarYu Kuai <yukuai@fnnas.com>
Reviewed-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 41afaeed

block/blk-mq-debugfs.c

+15 −8
Original line number Diff line number Diff line
@@ -631,14 +631,7 @@ void blk_mq_debugfs_register(struct request_queue *q) 
			blk_mq_debugfs_register_hctx(q, hctx);

	}



	if (q->rq_qos) {

		struct rq_qos *rqos = q->rq_qos;



		while (rqos) {

			blk_mq_debugfs_register_rqos(rqos);

			rqos = rqos->next;

		}

	}

	blk_mq_debugfs_register_rq_qos(q);

}



static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
@@ -769,6 +762,20 @@ void blk_mq_debugfs_register_rqos(struct rq_qos *rqos) 
	debugfs_create_files(rqos->debugfs_dir, rqos, rqos->ops->debugfs_attrs);

}



void blk_mq_debugfs_register_rq_qos(struct request_queue *q)

{

	lockdep_assert_held(&q->debugfs_mutex);



	if (q->rq_qos) {

		struct rq_qos *rqos = q->rq_qos;



		while (rqos) {

			blk_mq_debugfs_register_rqos(rqos);

			rqos = rqos->next;

		}

	}

}



void blk_mq_debugfs_register_sched_hctx(struct request_queue *q,

					struct blk_mq_hw_ctx *hctx)

{

block/blk-mq-debugfs.h

+5 −0
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ void blk_mq_debugfs_register_sched_hctx(struct request_queue *q, 
				       struct blk_mq_hw_ctx *hctx);

void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx);



void blk_mq_debugfs_register_rq_qos(struct request_queue *q);

void blk_mq_debugfs_register_rqos(struct rq_qos *rqos);

void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos);

#else
@@ -78,6 +79,10 @@ static inline void blk_mq_debugfs_register_rqos(struct rq_qos *rqos) 
{

}



static inline void blk_mq_debugfs_register_rq_qos(struct request_queue *q)

{

}



static inline void blk_mq_debugfs_unregister_rqos(struct rq_qos *rqos)

{

}