Commit b86d865c authored by Bart Van Assche's avatar Bart Van Assche Committed by Jens Axboe
Browse files

blkcg: Make blkg_root_lookup() work for queues in bypass mode 



For legacy queues the only call of blkg_root_lookup() happens after
bypass mode has been enabled. Since blkg_lookup() returns NULL for
queues in bypass mode, modify the blkg_root_lookup() such that it
no longer depends on bypass mode. Rename the function into
blk_queue_root_blkg() as suggested by Tejun.

Suggested-by: default avatarTejun Heo <tj@kernel.org>
Fixes: 6bad9b21 ("blkcg: Introduce blkg_root_lookup()")
Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 46451874

block/blk-sysfs.c

+1 −1
Original line number Diff line number Diff line
@@ -813,7 +813,7 @@ static void __blk_release_queue(struct work_struct *work) 
		blk_exit_queue(q);

	}



	WARN(blkg_root_lookup(q),

	WARN(blk_queue_root_blkg(q),

	     "request queue %p is being released but it has not yet been removed from the blkcg controller\n",

	     q);

include/linux/blk-cgroup.h

+5 −10
Original line number Diff line number Diff line
@@ -342,20 +342,14 @@ static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, 
}



/**

 * blkg_lookup - look up blkg for the specified request queue

 * blk_queue_root_blkg - return blkg for the (blkcg_root, @q) pair

 * @q: request_queue of interest

 *

 * Lookup blkg for @q at the root level. See also blkg_lookup().

 */

static inline struct blkcg_gq *blkg_root_lookup(struct request_queue *q)

static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q)

{

	struct blkcg_gq *blkg;



	rcu_read_lock();

	blkg = blkg_lookup(&blkcg_root, q);

	rcu_read_unlock();



	return blkg;

	return q->root_blkg;

}



/**
@@ -881,7 +875,8 @@ static inline bool blk_cgroup_congested(void) { return false; } 
static inline void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay) { }



static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }

static inline struct blkcg_gq *blkg_root_lookup(struct request_queue *q) { return NULL; }

static inline struct blkcg_gq *blk_queue_root_blkg(struct request_queue *q)

{ return NULL; }

static inline int blkcg_init_queue(struct request_queue *q) { return 0; }

static inline void blkcg_drain_queue(struct request_queue *q) { }

static inline void blkcg_exit_queue(struct request_queue *q) { }

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