[PATCH] fs/9p: Use an IS_ERR test rather than a NULL test

From: Julien Brunel
Date: Fri Sep 12 2008 - 10:23:40 EST


From: Julien Brunel <brunel@xxxxxxx>

In case of error, the function p9_client_walk 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 = p9_client_walk(...)
... when != x = E
* if (x != NULL)
S1 else S2
// </smpl>

Signed-off-by: Julien Brunel <brunel@xxxxxxx>
Signed-off-by: Julia Lawall <julia@xxxxxxx>

---
fs/9p/vfs_inode.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff -u -p a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -626,8 +626,7 @@ static struct dentry *v9fs_vfs_lookup(st
return NULL;

error:
- if (fid)
- p9_client_clunk(fid);
+ p9_client_clunk(fid);

return ERR_PTR(result);
}
--
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