target/linux/generic/patches-3.19/680-net-skip-gro-for-otherhost-packets.patch

   1 Subject: NET: skip GRO for otherhost packets
   2
   3 For network drivers using napi_gro_receive, packets are run through GRO,
   4 even when the destination MAC address does not match, and they're supposed
   5 to be delivered to another host behind a different bridge port.
   6
   7 This can be very expensive, because for drivers without TSO or scatter-
   8 gather, this can only be undone by copying the skb and checksumming it
   9 again.
  10
  11 Fix this by leaving skbs with PACKET_OTHERHOST untouched.
  12
  13 Signed-off-by: Felix Fietkau <nbd@openwrt.org>
  14
  15 --- a/net/core/dev.c
  16 +++ b/net/core/dev.c
  17 @@ -3967,6 +3967,9 @@ static enum gro_result dev_gro_receive(s
  18         enum gro_result ret;
  19         int grow;
  20
  21 +       if (skb->pkt_type == PACKET_OTHERHOST)
  22 +               goto normal;
  23 +
  24         if (!(skb->dev->features & NETIF_F_GRO))
  25                 goto normal;
  26