bonding/vlan: Fix mangled NAs on slaves without VLAN tag insertion

bond_na_send() attempts to insert a VLAN tag in between building and
sending packets of the respective formats.  If the slave does not
implement hardware VLAN tag insertion then vlan_put_tag() will mangle
the network-layer header because the Ethernet header is not present at
this point (unlike in bond_arp_send()).

Fix this by adding the tag out-of-line and relying on
dev_hard_start_xmit() to insert it inline if necessary.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NJay Vosburgh <fubar@us.ibm.com>
Reviewed-by: NJesse Gross <jesse@nicira.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_ipv6.c

@@ -88,7 +88,12 @@ static void bond_na_send(struct net_device *slave_dev,
 	}
 
 	if (vlan_id) {
-		skb = vlan_put_tag(skb, vlan_id);
+		/* The Ethernet header is not present yet, so it is
+		 * too early to insert a VLAN tag.  Force use of an
+		 * out-of-line tag here and let dev_hard_start_xmit()
+		 * insert it if the slave hardware can't.
+		 */
+		skb = __vlan_hwaccel_put_tag(skb, vlan_id);
 		if (!skb) {
 			pr_err("failed to insert VLAN tag\n");
 			return;