2008-02-26 20:46:34

by Julia Lawall

Subject: [PATCH 8/9] fs/ocfs2/aops.c: Correct use of ! and &

From: Julia Lawall <[email protected]>

In commit e6bafba5b4765a5a252f1b8d31cbf6d2459da337, a bug was fixed that
involved converting !x & y to !(x & y). The code below shows the same
pattern, and thus should perhaps be fixed in the same way.

This is not tested and clearly changes the semantics, so it is only
something to consider.

The semantic patch that makes this change is as follows:
(http://www.emn.fr/x-info/coccinelle/)

// <smpl>
@@ expression E1,E2; @@
(
!E1 & !E2
|
- !E1 & E2
+ !(E1 & E2)
)
// </smpl>

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

---

diff -u -p a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
--- a/fs/ocfs2/aops.c 2008-02-05 20:56:02.000000000 +0100
+++ b/fs/ocfs2/aops.c 2008-02-26 08:16:47.000000000 +0100
@@ -257,7 +257,7 @@ static int ocfs2_readpage_inline(struct
struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

BUG_ON(!PageLocked(page));
- BUG_ON(!OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL);
+ BUG_ON(!(OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL));

ret = ocfs2_read_block(osb, OCFS2_I(inode)->ip_blkno, &di_bh,
OCFS2_BH_CACHED, inode);

2008-02-27 21:27:29

by Mark Fasheh

Subject: Re: [PATCH 8/9] fs/ocfs2/aops.c: Correct use of ! and &

On Tue, Feb 26, 2008 at 09:45:56PM +0100, Julia Lawall wrote:
> From: Julia Lawall <[email protected]>
>
> In commit e6bafba5b4765a5a252f1b8d31cbf6d2459da337, a bug was fixed that
> involved converting !x & y to !(x & y). The code below shows the same
> pattern, and thus should perhaps be fixed in the same way.
>
> This is not tested and clearly changes the semantics, so it is only
> something to consider.

That looks fine - it's in Ocfs2.git now, thanks.
--Mark

--
Mark Fasheh
Principal Software Developer, Oracle
[email protected]