Merge branch 'skb-gro-optimize'

Paolo Abeni says:

====================
sk_buff: optimize GRO for the common case

This is a trimmed down revision of "sk_buff: optimize layout for GRO",
specifically dropping the changes to the sk_buff layout[1].

This series tries to accomplish 2 goals:
- optimize the GRO stage for the most common scenario, avoiding a bunch
  of conditional and some more code
- let owned skbs entering the GRO engine, allowing backpressure in the
  veth GRO forward path.

A new sk_buff flag (!!!) is introduced and maintained for GRO's sake.
Such field uses an existing hole, so there is no change to the sk_buff
size.

[1] two main reasons:
- move skb->inner_ field requires some extra care, as some in kernel
  users access and the fields regardless of skb->encapsulation.
- extending secmark size clash with ct and nft uAPIs

address the all above is possible, I think, but for sure not in a single
series.
====================

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