s390/qeth: extract csum offload helpers

This consolidates the checksum offload code that was duplicated
over the two qeth subdrivers.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 0e8ed87..bc359e3 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -1367,17 +1367,7 @@ static void qeth_l3_rebuild_skb(struct qeth_card *card, struct sk_buff *skb,
 		__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), tag);
 	}
 
-	if (card->dev->features & NETIF_F_RXCSUM) {
-		if ((hdr->hdr.l3.ext_flags &
-		    (QETH_HDR_EXT_CSUM_HDR_REQ |
-		     QETH_HDR_EXT_CSUM_TRANSP_REQ)) ==
-		    (QETH_HDR_EXT_CSUM_HDR_REQ |
-		     QETH_HDR_EXT_CSUM_TRANSP_REQ))
-			skb->ip_summed = CHECKSUM_UNNECESSARY;
-		else
-			skb->ip_summed = CHECKSUM_NONE;
-	} else
-		skb->ip_summed = CHECKSUM_NONE;
+	qeth_rx_csum(card, skb, hdr->hdr.l3.ext_flags);
 }
 
 static int qeth_l3_process_inbound_buffer(struct qeth_card *card,
@@ -2123,23 +2113,6 @@ static void qeth_l3_fill_header(struct qeth_card *card, struct qeth_hdr *hdr,
 	rcu_read_unlock();
 }
 
-static void qeth_l3_hdr_csum(struct qeth_card *card, struct qeth_hdr *hdr,
-			     struct sk_buff *skb)
-{
-	struct iphdr *iph = ip_hdr(skb);
-
-	/* tcph->check contains already the pseudo hdr checksum
-	 * so just set the header flags
-	 */
-	if (iph->protocol == IPPROTO_UDP)
-		hdr->hdr.l3.ext_flags |= QETH_HDR_EXT_UDP;
-	hdr->hdr.l3.ext_flags |= QETH_HDR_EXT_CSUM_TRANSP_REQ |
-		QETH_HDR_EXT_CSUM_HDR_REQ;
-	iph->check = 0;
-	if (card->options.performance_stats)
-		card->perf_stats.tx_csum++;
-}
-
 static void qeth_tso_fill_header(struct qeth_card *card,
 		struct qeth_hdr *qhdr, struct sk_buff *skb)
 {
@@ -2331,8 +2304,11 @@ static netdev_tx_t qeth_l3_hard_start_xmit(struct sk_buff *skb,
 			}
 		}
 
-		if (skb->ip_summed == CHECKSUM_PARTIAL)
-			qeth_l3_hdr_csum(card, hdr, new_skb);
+		if (new_skb->ip_summed == CHECKSUM_PARTIAL) {
+			qeth_tx_csum(new_skb, &hdr->hdr.l3.ext_flags);
+			if (card->options.performance_stats)
+				card->perf_stats.tx_csum++;
+		}
 	}
 
 	elements = use_tso ?