[PATCH 4/7] fs/direct-io.c: adjust suspicious bit operation

[PATCH 4/7] fs/direct-io.c: adjust suspicious bit operation

[Julia Lawall]

From: Julia Lawall <Julia.Lawall@lip6.fr>

READ is 0, so the result of the bit-and operation is 0.  Rewrite with == as
done elsewhere in the same file.

This problem was found using Coccinelle (http://coccinelle.lip6.fr/).

Signed-off-by: Julia Lawall <julia@diku.dk>

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

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 0c85fae..1faf4cb 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -1258,7 +1258,7 @@ do_blockdev_direct_IO(int rw, struct kiocb *iocb, struct inode *inode,
 	 */
 	BUG_ON(retval == -EIOCBQUEUED);
 	if (dio->is_async && retval == 0 && dio->result &&
-	    ((rw & READ) || (dio->result == sdio.size)))
+	    ((rw == READ) || (dio->result == sdio.size)))
 		retval = -EIOCBQUEUED;
 
 	if (retval != -EIOCBQUEUED)

Re: [PATCH 4/7] fs/direct-io.c: adjust suspicious bit operation

[Jeff Moyer]

Julia Lawall <Julia.Lawall@lip6.fr> writes:

> From: Julia Lawall <Julia.Lawall@lip6.fr>
>
> READ is 0, so the result of the bit-and operation is 0.  Rewrite with == as
> done elsewhere in the same file.
>
> This problem was found using Coccinelle (http://coccinelle.lip6.fr/).

Interesting catch, that one.  Yeah, we don't expect any readahead I/O to
be done via O_DIRECT.  The test for rw == READ all over that file seems
fine to me, given that.

Reviewed-by: Jeff Moyer <jmoyer@redhat.com>