s390/qeth: avoid null pointer dereference on OSN

[ Upstream commit 25e2c341 ]

Access card->dev only after checking whether's its valid.
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Reviewed-by: Ursula Braun <ubraun@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/s390/net/qeth_l2_main.c

@@ -1112,7 +1112,6 @@ static int qeth_l2_setup_netdev(struct qeth_card *card)
 	case QETH_CARD_TYPE_OSN:
 		card->dev = alloc_netdev(0, "osn%d", NET_NAME_UNKNOWN,
 					 ether_setup);
-		card->dev->flags |= IFF_NOARP;
 		break;
 	default:
 		card->dev = alloc_etherdev(0);
@@ -1125,9 +1124,12 @@ static int qeth_l2_setup_netdev(struct qeth_card *card)
 	card->dev->watchdog_timeo = QETH_TX_TIMEOUT;
 	card->dev->mtu = card->info.initial_mtu;
 	card->dev->netdev_ops = &qeth_l2_netdev_ops;
-	card->dev->ethtool_ops =
-		(card->info.type != QETH_CARD_TYPE_OSN) ?
-		&qeth_l2_ethtool_ops : &qeth_l2_osn_ops;
+	if (card->info.type == QETH_CARD_TYPE_OSN) {
+		card->dev->ethtool_ops = &qeth_l2_osn_ops;
+		card->dev->flags |= IFF_NOARP;
+	} else {
+		card->dev->ethtool_ops = &qeth_l2_ethtool_ops;
+	}
 	card->dev->features |= NETIF_F_HW_VLAN_CTAG_FILTER;
 	if (card->info.type == QETH_CARD_TYPE_OSD && !card->info.guestlan) {
 		card->dev->hw_features = NETIF_F_IP_CSUM | NETIF_F_RXCSUM;