[PATCH] cdrom buffer too small

dvd_read_physical() uses a 20 char buffer to read in the dvd structure,
however the size is really 4 bytes header + 17 bytes body so layer->bca
ends up containing garbage. Kudos to the nice folks who made it a non
multiple of 4 bytes.

drivers/cdrom/cdrom.c

@@ -1125,7 +1125,7 @@ static int dvd_do_auth(struct cdrom_device_info *cdi, dvd_authinfo *ai)
 
 static int dvd_read_physical(struct cdrom_device_info *cdi, dvd_struct *s)
 {
-	unsigned char buf[20], *base;
+	unsigned char buf[21], *base;
 	struct dvd_layer *layer;
 	struct cdrom_generic_command cgc;
 	struct cdrom_device_ops *cdo = cdi->ops;