netdev - Re: [PATCH RFC net-next 00/11] udp gso

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Message-ID: <CAF=yD-JX--1m8owpS+EqNAhU6rP-8KCDDXC51HNpRss4px6yig@mail.gmail.com>
Date:   Fri, 20 Apr 2018 17:58:14 -0400
From:   Willem de Bruijn <willemdebruijn.kernel@...il.com>
To:     Alexander Duyck <alexander.duyck@...il.com>
Cc:     David Miller <davem@...emloft.net>,
        Sowmini Varadhan <sowmini.varadhan@...cle.com>,
        "Samudrala, Sridhar" <sridhar.samudrala@...el.com>,
        Netdev <netdev@...r.kernel.org>,
        Willem de Bruijn <willemb@...gle.com>
Subject: Re: [PATCH RFC net-next 00/11] udp gso

>>> 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.