blkcg: s/RQ_QOS_CGROUP/RQ_QOS_LATENCY/

io.weight is gonna be another rq_qos cgroup mechanism.  Let's rename
RQ_QOS_CGROUP which is being used by io.latency to RQ_QOS_LATENCY in
preparation.
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-iolatency.c

@@ -725,7 +725,7 @@ int blk_iolatency_init(struct request_queue *q)
 		return -ENOMEM;
 
 	rqos = &blkiolat->rqos;
-	rqos->id = RQ_QOS_CGROUP;
+	rqos->id = RQ_QOS_LATENCY;
 	rqos->ops = &blkcg_iolatency_ops;
 	rqos->q = q;
 

block/blk-rq-qos.h

@@ -14,7 +14,7 @@ struct blk_mq_debugfs_attr;
 
 enum rq_qos_id {
 	RQ_QOS_WBT,
-	RQ_QOS_CGROUP,
+	RQ_QOS_LATENCY,
 };
 
 struct rq_wait {
@@ -74,7 +74,7 @@ static inline struct rq_qos *wbt_rq_qos(struct request_queue *q)
 
 static inline struct rq_qos *blkcg_rq_qos(struct request_queue *q)
 {
-	return rq_qos_id(q, RQ_QOS_CGROUP);
+	return rq_qos_id(q, RQ_QOS_LATENCY);
 }
 
 static inline const char *rq_qos_id_to_name(enum rq_qos_id id)
@@ -82,8 +82,8 @@ static inline const char *rq_qos_id_to_name(enum rq_qos_id id)
 	switch (id) {
 	case RQ_QOS_WBT:
 		return "wbt";
-	case RQ_QOS_CGROUP:
-		return "cgroup";
+	case RQ_QOS_LATENCY:
+		return "latency";
 	}
 	return "unknown";
 }