geneve: avoid indirect calls in GRO path, when possible

In the most common setups, the geneve tunnels use an inner
ethernet encapsulation. In the GRO path, when such condition is
true, we can call directly the relevant GRO helper and avoid
a few indirect calls.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/geneve.c

@@ -533,14 +533,16 @@ static struct sk_buff *geneve_gro_receive(struct sock *sk,
 		}
 	}
 
+	skb_gro_pull(skb, gh_len);
+	skb_gro_postpull_rcsum(skb, gh, gh_len);
 	type = gh->proto_type;
+	if (likely(type == htons(ETH_P_TEB)))
+		return call_gro_receive(eth_gro_receive, head, skb);
 
 	ptype = gro_find_receive_by_type(type);
 	if (!ptype)
 		goto out;
 
-	skb_gro_pull(skb, gh_len);
-	skb_gro_postpull_rcsum(skb, gh, gh_len);
 	pp = call_gro_receive(ptype->callbacks.gro_receive, head, skb);
 	flush = 0;
 
@@ -563,6 +565,10 @@ static int geneve_gro_complete(struct sock *sk, struct sk_buff *skb,
 	gh_len = geneve_hlen(gh);
 	type = gh->proto_type;
 
+	/* since skb->encapsulation is set, eth_gro_complete() sets the inner mac header */
+	if (likely(type == htons(ETH_P_TEB)))
+		return eth_gro_complete(skb, nhoff + gh_len);
+
 	ptype = gro_find_complete_by_type(type);
 	if (ptype)
 		err = ptype->callbacks.gro_complete(skb, nhoff + gh_len);