ibmvnic: Include header descriptor support for ARP packets

In recent tests with new adapters, it was discovered that ARP
packets were not being properly processed. This patch adds
support for ARP packet headers to be passed to backing adapters,
if necessary.
Signed-off-by: NThomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/ibm/ibmvnic.c

@@ -59,6 +59,7 @@
 #include <linux/mm.h>
 #include <linux/ethtool.h>
 #include <linux/proc_fs.h>
+#include <linux/if_arp.h>
 #include <linux/in.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
@@ -1153,6 +1154,9 @@ static int build_hdr_data(u8 hdr_field, struct sk_buff *skb,
 			hdr_len[2] = tcp_hdrlen(skb);
 		else if (ipv6_hdr(skb)->nexthdr == IPPROTO_UDP)
 			hdr_len[2] = sizeof(struct udphdr);
+	} else if (skb->protocol == htons(ETH_P_ARP)) {
+		hdr_len[1] = arp_hdr_len(skb->dev);
+		hdr_len[2] = 0;
 	}
 
 	memset(hdr_data, 0, 120);
@@ -1386,7 +1390,8 @@ static int ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
 	/* determine if l2/3/4 headers are sent to firmware */
 	if ((*hdrs >> 7) & 1 &&
 	    (skb->protocol == htons(ETH_P_IP) ||
-	     skb->protocol == htons(ETH_P_IPV6))) {
+	     skb->protocol == htons(ETH_P_IPV6) ||
+	     skb->protocol == htons(ETH_P_ARP))) {
 		build_hdr_descs_arr(tx_buff, &num_entries, *hdrs);
 		tx_crq.v1.n_crq_elem = num_entries;
 		tx_buff->indir_arr[0] = tx_crq;