Merge branch 'SO_PRIORITY'

Merge branch 'SO_PRIORITY'

Eric Dumazet says:

====================
tcp: provide correct skb->priority

SO_PRIORITY socket option requests TCP egress packets
to contain a user provided value.

TCP manages to send most packets with the requested values,
notably for TCP_ESTABLISHED state, but fails to do so for
few packets.

These packets are control packets sent on behalf
of SYN_RECV or TIME_WAIT states.

Note that to test this with packetdrill, it is a bit
of a hassle, since packetdrill can not verify priority
of egress packets, other than indirect observations,
using for example sch_prio on its tunnel device.

The bad skb priorities cause problems for GCP,
as this field is one of the keys used in routing.
====================

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