s390/qeth: increase GSO max size for eligible L3 devices

When a L3 device doesn't offer TSO, allow the stack to build full-size
GSO skbs.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_l3_main.c

@@ -2536,8 +2536,9 @@ static int qeth_l3_setup_netdev(struct qeth_card *card)
 				NETIF_F_HW_VLAN_CTAG_RX |
 				NETIF_F_HW_VLAN_CTAG_FILTER;
 	netif_keep_dst(card->dev);
-	netif_set_gso_max_size(card->dev, (QETH_MAX_BUFFER_ELEMENTS(card) - 1) *
-					  PAGE_SIZE);
+	if (card->dev->hw_features & NETIF_F_TSO)
+		netif_set_gso_max_size(card->dev,
+				       PAGE_SIZE * (QETH_MAX_BUFFER_ELEMENTS(card) - 1));
 
 	SET_NETDEV_DEV(card->dev, &card->gdev->dev);
 	netif_napi_add(card->dev, &card->napi, qeth_poll, QETH_NAPI_WEIGHT);