kernel: add missing description for GRO optimization patch

[15.05/openwrt.git] / target / linux / generic / patches-4.0 / 680-net-skip-gro-for-otherhost-packets.patch

diff --git a/target/linux/generic/patches-4.0/680-net-skip-gro-for-otherhost-packets.patch b/target/linux/generic/patches-4.0/680-net-skip-gro-for-otherhost-packets.patch
index fc36258..62e0bde 100644 (file)
--- a/target/linux/generic/patches-4.0/680-net-skip-gro-for-otherhost-packets.patch
+++ b/target/linux/generic/patches-4.0/680-net-skip-gro-for-otherhost-packets.patch
@@ -1,3 +1,17 @@
+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
 @@ -4005,6 +4005,9 @@ static enum gro_result dev_gro_receive(s