Subject: NET: skip GRO for otherhost packets

For network drivers using napi_gro_receive, packets are run through GRO,
even when the destination MAC address does not match, and they're supposed
to be delivered to another host behind a different bridge port.

This can be very expensive, because for drivers without TSO or scatter-
gather, this can only be undone by copying the skb and checksumming it
again.

Fix this by leaving skbs with PACKET_OTHERHOST untouched.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4003,6 +4003,9 @@ static enum gro_result dev_gro_receive(s
 	enum gro_result ret;
 	int grow;
 
+	if (skb->pkt_type == PACKET_OTHERHOST)
+		goto normal;
+
 	if (!(skb->dev->features & NETIF_F_GRO))
 		goto normal;
 
