Reduce path_lookup() abuses

... use kern_path() where possible

[folded a fix from rdd]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index 650a730..1ff9473 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1282,21 +1282,21 @@
 static struct super_block *get_gfs2_sb(const char *dev_name)
 {
 	struct super_block *sb;
-	struct nameidata nd;
+	struct path path;
 	int error;
 
-	error = path_lookup(dev_name, LOOKUP_FOLLOW, &nd);
+	error = kern_path(dev_name, LOOKUP_FOLLOW, &path);
 	if (error) {
 		printk(KERN_WARNING "GFS2: path_lookup on %s returned error %d\n",
 		       dev_name, error);
 		return NULL;
 	}
-	sb = nd.path.dentry->d_inode->i_sb;
+	sb = path.dentry->d_inode->i_sb;
 	if (sb && (sb->s_type == &gfs2_fs_type))
 		atomic_inc(&sb->s_active);
 	else
 		sb = NULL;
-	path_put(&nd.path);
+	path_put(&path);
 	return sb;
 }