blkcg: misc preparations for unified hierarchy interface

* Export blkg_dev_name()

* Drop unnecessary @cft from __cfq_set_weight().
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@fb.com>

block/blk-cgroup.c

@@ -462,13 +462,14 @@ static int blkcg_reset_stats(struct cgroup_subsys_state *css,
 	return 0;
 }
 
-static const char *blkg_dev_name(struct blkcg_gq *blkg)
+const char *blkg_dev_name(struct blkcg_gq *blkg)
 {
 	/* some drivers (floppy) instantiate a queue w/o disk registered */
 	if (blkg->q->backing_dev_info.dev)
 		return dev_name(blkg->q->backing_dev_info.dev);
 	return NULL;
 }
+EXPORT_SYMBOL_GPL(blkg_dev_name);
 
 /**
  * blkcg_print_blkgs - helper for printing per-blkg data

block/cfq-iosched.c

@@ -1788,8 +1788,8 @@ static ssize_t cfqg_set_leaf_weight_device(struct kernfs_open_file *of,
 	return __cfqg_set_weight_device(of, buf, nbytes, off, true);
 }
 
-static int __cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft,
-			    u64 val, bool is_leaf_weight)
+static int __cfq_set_weight(struct cgroup_subsys_state *css, u64 val,
+			    bool is_leaf_weight)
 {
 	struct blkcg *blkcg = css_to_blkcg(css);
 	struct blkcg_gq *blkg;
@@ -1834,13 +1834,13 @@ static int __cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft,
 static int cfq_set_weight(struct cgroup_subsys_state *css, struct cftype *cft,
 			  u64 val)
 {
-	return __cfq_set_weight(css, cft, val, false);
+	return __cfq_set_weight(css, val, false);
 }
 
 static int cfq_set_leaf_weight(struct cgroup_subsys_state *css,
 			       struct cftype *cft, u64 val)
 {
-	return __cfq_set_weight(css, cft, val, true);
+	return __cfq_set_weight(css, val, true);
 }
 
 static int cfqg_print_stat(struct seq_file *sf, void *v)

include/linux/blk-cgroup.h

@@ -182,6 +182,7 @@ int blkcg_activate_policy(struct request_queue *q,
 void blkcg_deactivate_policy(struct request_queue *q,
 			     const struct blkcg_policy *pol);
 
+const char *blkg_dev_name(struct blkcg_gq *blkg);
 void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
 		       u64 (*prfill)(struct seq_file *,
 				     struct blkg_policy_data *, int),