kernfs: remove kernfs_path_len()

It doesn't have any in-kernel user and the same result can be obtained
from kernfs_path(@kn, NULL, 0).  Remove it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Serge Hallyn <serge.hallyn@ubuntu.com>

fs/kernfs/dir.c

@@ -179,29 +179,6 @@ int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
 	return ret;
 }
 
-/**
- * kernfs_path_len - determine the length of the full path of a given node
- * @kn: kernfs_node of interest
- *
- * The returned length doesn't include the space for the terminating '\0'.
- */
-size_t kernfs_path_len(struct kernfs_node *kn)
-{
-	size_t len = 0;
-	unsigned long flags;
-
-	spin_lock_irqsave(&kernfs_rename_lock, flags);
-
-	do {
-		len += strlen(kn->name) + 1;
-		kn = kn->parent;
-	} while (kn && kn->parent);
-
-	spin_unlock_irqrestore(&kernfs_rename_lock, flags);
-
-	return len;
-}
-
 /**
  * kernfs_path_from_node - build path of node @to relative to @from.
  * @from: parent kernfs_node relative to which we need to build the path

include/linux/kernfs.h

@@ -269,7 +269,6 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
 }
 
 int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
-size_t kernfs_path_len(struct kernfs_node *kn);
 int kernfs_path_from_node(struct kernfs_node *root_kn, struct kernfs_node *kn,
 			  char *buf, size_t buflen);
 void pr_cont_kernfs_name(struct kernfs_node *kn);
@@ -340,9 +339,6 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
 static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
 { return -ENOSYS; }
 
-static inline size_t kernfs_path_len(struct kernfs_node *kn)
-{ return 0; }
-
 static inline int kernfs_path_from_node(struct kernfs_node *root_kn,
 					struct kernfs_node *kn,
 					char *buf, size_t buflen)