constify dentry argument of dentry_path()/dentry_path_raw()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/d_path.c b/fs/d_path.c
index a69e2cd..270d621 100644
--- a/fs/d_path.c
+++ b/fs/d_path.c
@@ -326,9 +326,9 @@ char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
 /*
  * Write full pathname from the root of the filesystem into the buffer.
  */
-static char *__dentry_path(struct dentry *d, char *buf, int buflen)
+static char *__dentry_path(const struct dentry *d, char *buf, int buflen)
 {
-	struct dentry *dentry;
+	const struct dentry *dentry;
 	char *end, *retval;
 	int len, seq = 0;
 	int error = 0;
@@ -347,7 +347,7 @@ static char *__dentry_path(struct dentry *d, char *buf, int buflen)
 	*retval = '/';
 	read_seqbegin_or_lock(&rename_lock, &seq);
 	while (!IS_ROOT(dentry)) {
-		struct dentry *parent = dentry->d_parent;
+		const struct dentry *parent = dentry->d_parent;
 
 		prefetch(parent);
 		error = prepend_name(&end, &len, &dentry->d_name);
@@ -371,13 +371,13 @@ static char *__dentry_path(struct dentry *d, char *buf, int buflen)
 	return ERR_PTR(-ENAMETOOLONG);
 }
 
-char *dentry_path_raw(struct dentry *dentry, char *buf, int buflen)
+char *dentry_path_raw(const struct dentry *dentry, char *buf, int buflen)
 {
 	return __dentry_path(dentry, buf, buflen);
 }
 EXPORT_SYMBOL(dentry_path_raw);
 
-char *dentry_path(struct dentry *dentry, char *buf, int buflen)
+char *dentry_path(const struct dentry *dentry, char *buf, int buflen)
 {
 	char *p = NULL;
 	char *retval;