On Fri, Apr 20, 2018 at 2:58 PM, Willem de Bruijn
[off-list ref] wrote:

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Also any plans for HW offload support for this? I vaguely recall that
the igb and ixgbe parts had support for something like this in
hardware. I would have to double check to see what exactly is
supported.

I hadn't given that much thought until the request yesterday to
expose the NETIF_F_GSO_UDP_L4 flag through ethtool. By
virtue of having only a single fixed segmentation length, it
appears reasonably straightforward to offload.

Actually I just got a chance to start on a review of things. Do we
need to have to use both GSO_UDP and and GSO_UDP_L4? It might be
better if we could split these up and specifically call out GSO_UDP as
UFO and GSO_UDP_L4 as being UDP segmentation.

Thanks for taking a look, Alex.

Agreed, I'll revise that. My initial thought was that both gso skbs need
to take the same udp gso special case branches in places like act_csum
and ovs. But on rereading that seems an unsafe approach, as some
branches are fragmentation specific. I'll review them all and add
separate SKB_GSO_UDP_L4 cases where needed, instead.

Sounds good. Keep me in the loop on these patches. I will see if we
can get support for ixgbe, ixgbevf, and igb to at least offload this
since it shouldn't be much of a lift to get that. Once we have that I
can also take a look and see if there would be much work needed to add
gso_partial support so we could deal with tunnel encapsulated UDP
segmentation offload support on those devices.

Thanks.

- Alex