openvswitch: fix vlan subtraction from packet length

When the packet has its vlan tag in skb->vlan_tci, the length of the VLAN
header is not counted in skb->len. It doesn't make sense to subtract it.

Fixes: 018c1dda ("openvswitch: 802.1AD Flow handling, actions, vlan parsing, netlink attributes")
Signed-off-by: NJiri Benc <jbenc@redhat.com>
Acked-by: NPravin B Shelar <pshelar@ovn.org>
Acked-by: NEric Garver <e@erig.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/openvswitch/vport.c

@@ -485,7 +485,8 @@ static unsigned int packet_length(const struct sk_buff *skb)
 {
 	unsigned int length = skb->len - ETH_HLEN;
 
-	if (skb_vlan_tagged(skb))
+	if (!skb_vlan_tag_present(skb) &&
+	    eth_type_vlan(skb->protocol))
 		length -= VLAN_HLEN;
 
 	/* Don't subtract for multiple VLAN tags. Most (all?) drivers allow