[S390] drivers/s390: put NULL test before dereference
authorJulia Lawall <julia@diku.dk>
Sun, 23 Aug 2009 16:09:05 +0000 (18:09 +0200)
committerMartin Schwidefsky <schwidefsky@de.ibm.com>
Sun, 23 Aug 2009 16:10:00 +0000 (18:10 +0200)
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>
drivers/s390/block/dasd.c

index 749836668655980c0111be468bbdb8c3edd70e98..3f62dd50bbbe0afeef786877c1de7234ff80662d 100644 (file)
@@ -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)