From: Julia Lawall <julia@diku.dk>
Date: Sun, 23 Aug 2009 16:09:05 +0000 (+0200)
Subject: [S390] drivers/s390: put NULL test before dereference
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=cf05b824dbb871159e1b4c4f2733b9c9d2f756cf;p=linux.git

[S390] drivers/s390: put NULL test before dereference

If the NULL test on block is needed, it should be before the dereference of
the base field.

The semantic match that finds this problem is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@r@
expression E1,E2;
identifier fld;
statement S1,S2;
@@

E1 = E2->fld;
(
if (E1 == NULL) S1 else S2
|
*if (E2 == NULL) S1 else S2
)
// </smpl>

Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 7498366686559..3f62dd50bbbe0 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -2135,9 +2135,9 @@ static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 	struct dasd_device *base;
 
 	block = bdev->bd_disk->private_data;
-	base = block->base;
 	if (!block)
 		return -ENODEV;
+	base = block->base;
 
 	if (!base->discipline ||
 	    !base->discipline->fill_geometry)