Merge branch 'gro-in-udp'

Tom Herbert says:

====================
udp: GRO in UDP sockets

This patch set adds GRO functions (gro_receive and gro_complete) to UDP
sockets and removes udp_offload infrastructure.

Add GRO functions (gro_receive and gro_complete) to UDP sockets. In
udp_gro_receive and udp_gro_complete a socket lookup is done instead of
looking up the port number in udp_offloads.  If a socket is found and
there are GRO functions for it then those are called. This feature
allows binding GRO functions to more than just a port number.
Eventually, we will be able to use this technique to allow application
defined GRO for an application protocol by attaching BPF porgrams to UDP
sockets for doing GRO.

In order to implement these functions, we added exported
udp6_lib_lookup_skb and udp4_lib_lookup_skb functions in ipv4/udp.c and
ipv6/udp.c. Also, inet_iif and references to skb_dst() were changed to
check that dst is set in skbuf before derefencing. In the GRO path there
is now a UDP socket lookup performed before dst is set, to the get the
device in that case we simply use skb->dev.

Tested:

Ran various combinations of VXLAN and GUE TCP_STREAM and TCP_RR tests.
Did not see any material regression.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>