2008-08-29 09:16:41

by Julien Brunel

Subject: [PATCH] fs/ubifs: Use an IS_ERR test rather than a NULL test

From: Julien Brunel <[email protected]>

In case of error, the function kthread_create returns an ERR pointer,
but never returns a NULL pointer. So a NULL test that comes before 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 = kthread_create(...)
... when != x = E
* if (x == NULL)
S1 else S2
// </smpl>

Signed-off-by: Julien Brunel <[email protected]>
Signed-off-by: Julia Lawall <[email protected]>

---
fs/ubifs/super.c | 4 ----
1 file changed, 4 deletions(-)

diff -u -p a/fs/ubifs/super.c b/fs/ubifs/super.c
--- a/fs/ubifs/super.c
+++ b/fs/ubifs/super.c
@@ -1027,8 +1027,6 @@ static int mount_ubifs(struct ubifs_info
sprintf(c->bgt_name, BGT_NAME_PATTERN, c->vi.ubi_num,
c->vi.vol_id);
c->bgt = kthread_create(ubifs_bg_thread, c, c->bgt_name);
- if (!c->bgt)
- c->bgt = ERR_PTR(-EINVAL);
if (IS_ERR(c->bgt)) {
err = PTR_ERR(c->bgt);
c->bgt = NULL;
@@ -1340,8 +1338,6 @@ static int ubifs_remount_rw(struct ubifs

/* Create background thread */
c->bgt = kthread_create(ubifs_bg_thread, c, c->bgt_name);
- if (!c->bgt)
- c->bgt = ERR_PTR(-EINVAL);
if (IS_ERR(c->bgt)) {
err = PTR_ERR(c->bgt);
c->bgt = NULL;

2008-08-29 10:38:55

by Artem Bityutskiy

Subject: Re: [PATCH] fs/ubifs: Use an IS_ERR test rather than a NULL test

On Fri, 2008-08-29 at 11:08 +0200, Julien Brunel wrote:
> In case of error, the function kthread_create returns an ERR pointer,
> but never returns a NULL pointer. So a NULL test that comes before an
> IS_ERR test should be deleted.
>
> The semantic match that finds this problem is as follows:
> (http://www.emn.fr/x-info/coccinelle/)

Pushed to ubifs-2.6.git, thanks.

--
Best regards,
Artem Bityutskiy (Битюцкий Артём)