fs/reiserfs: Use an IS_ERR test rather than a NULL test

From: Julien Brunel <[email protected]>

In case of error, the function open_xa_dir returns an ERR pointer, but never returns a NULL pointer. So a NULL test that comes after an IS_ERR test should be deleted.

The semantic match that finds this problem is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@match_bad_null_test@
expression x, E;
statement S1,S2;
@@
x = open_xa_dir(...)
... when != x = E
(
* if (x = NULL && ...) S1 else S2
|
* if (x = NULL || ...) S1 else S2
)
// </smpl>

---
 fs/reiserfs/xattr.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -u -p a/fs/reiserfs/xattr.c b/fs/reiserfs/xattr.c
@@ -155,7 +155,7 @@ static struct dentry *get_xa_file_dentry
 	xadir = open_xa_dir(inode, flags);
 	if (IS_ERR(xadir)) {
 		return ERR_CAST(xadir);
-	} else if (xadir && !xadir->d_inode) {
+	} else if (!xadir->d_inode) {
 		dput(xadir);
 		return ERR_PTR(-ENODATA);
 	}