qla3xxx: cleanup checksum offload code

The code for checksum is more complex than needed when dealing with VLAN's;
the higher layers already pass down the location of the IP header.

Compile tested only, no hardware available.
Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: Ron Mercer <ron.mercer@qlogic.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

drivers/net/qla3xxx.c

@@ -2433,37 +2433,22 @@ static int ql_get_seg_count(struct ql3_adapter *qdev,
 	return -1;
 }
 
-static void ql_hw_csum_setup(struct sk_buff *skb,
+static void ql_hw_csum_setup(const struct sk_buff *skb,
 			     struct ob_mac_iocb_req *mac_iocb_ptr)
 {
-	struct ethhdr *eth;
-	struct iphdr *ip = NULL;
-	u8 offset = ETH_HLEN;
+	const struct iphdr *ip = ip_hdr(skb);
 
-	eth = (struct ethhdr *)(skb->data);
-
-	if (eth->h_proto == __constant_htons(ETH_P_IP)) {
-		ip = (struct iphdr *)&skb->data[ETH_HLEN];
-	} else if (eth->h_proto == htons(ETH_P_8021Q) &&
-		   ((struct vlan_ethhdr *)skb->data)->
-		   h_vlan_encapsulated_proto == __constant_htons(ETH_P_IP)) {
-		ip = (struct iphdr *)&skb->data[VLAN_ETH_HLEN];
-		offset = VLAN_ETH_HLEN;
-	}
+	mac_iocb_ptr->ip_hdr_off = skb_network_offset(skb);
+	mac_iocb_ptr->ip_hdr_len = ip->ihl;
 
-	if (ip) {
 	if (ip->protocol == IPPROTO_TCP) {
 		mac_iocb_ptr->flags1 |= OB_3032MAC_IOCB_REQ_TC |
 			OB_3032MAC_IOCB_REQ_IC;
-			mac_iocb_ptr->ip_hdr_off = offset;
-			mac_iocb_ptr->ip_hdr_len = ip->ihl;
-		} else if (ip->protocol == IPPROTO_UDP) {
+	} else {
 		mac_iocb_ptr->flags1 |= OB_3032MAC_IOCB_REQ_UC |
 			OB_3032MAC_IOCB_REQ_IC;
-			mac_iocb_ptr->ip_hdr_off = offset;
-			mac_iocb_ptr->ip_hdr_len = ip->ihl;
-		}
 	}
+
 }
 
 /*