switch open-coded instances of d_make_root() to new helper

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/ocfs2/dlmfs/dlmfs.c b/fs/ocfs2/dlmfs/dlmfs.c
index abfac0d..3b5825e 100644
--- a/fs/ocfs2/dlmfs/dlmfs.c
+++ b/fs/ocfs2/dlmfs/dlmfs.c
@@ -582,24 +582,14 @@
 			    void * data,
 			    int silent)
 {
-	struct inode * inode;
-	struct dentry * root;
-
 	sb->s_maxbytes = MAX_LFS_FILESIZE;
 	sb->s_blocksize = PAGE_CACHE_SIZE;
 	sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
 	sb->s_magic = DLMFS_MAGIC;
 	sb->s_op = &dlmfs_ops;
-	inode = dlmfs_get_root_inode(sb);
-	if (!inode)
+	sb->s_root = d_make_root(dlmfs_get_root_inode(sb));
+	if (!sb->s_root)
 		return -ENOMEM;
-
-	root = d_alloc_root(inode);
-	if (!root) {
-		iput(inode);
-		return -ENOMEM;
-	}
-	sb->s_root = root;
 	return 0;
 }