Re: [PATCH net-next] net-gre-gro: Fix a bug that breaks the forwarding path

[Jerry Chu <hkchu@google.com>]

On Mon, Jul 14, 2014 at 1:38 PM, Or Gerlitz <or.gerlitz@gmail.com> wrote:
> On Mon, Jul 14, 2014 at 10:16 PM, Jerry Chu <hkchu@google.com> wrote:
>> On Mon, Jul 14, 2014 at 12:05 PM, Or Gerlitz <or.gerlitz@gmail.com> wrote:
>>> On Sun, Jul 13, 2014 at 5:46 PM, H.K. Jerry Chu <hkchu@google.com> wrote:
>>>> Fixed a bug that was introduced by my GRE-GRO patch
>>>> (bf5a755f5e9186406bbf50f4087100af5bd68e40 net-gre-gro: Add GRE
>>>> support to the GRO stack) that breaks the forwarding path
>>>> because various GSO related fields were not set. The bug will
>>>> cause on the egress path either the GSO code to fail, or a
>>>> GRE-TSO capable (NETIF_F_GSO_GRE) NICs to choke. The following
>>>> fix has been tested for both cases.
>
>>> Anything different in this version vs. the one you posted earlier on
>>> February or this is a plain re-post?
>
>> I simply moved the patch against the latest net-next and resolved some small
>> conflict so yes it's pretty much the same.
>
> OK, got it.
>
>> Also I don't see the subsequent
>> discussion on skb->encapsulation affects the validity of this patch so
>> i'm resubmitting it. Also the patch has been confirmed to address the problem
>> Wolfgang reported last week. Feel free to test against the configuration (VXLAN?)
>> you had some question about earlier.
>
> Well, re-reading that thread, we were not very decisive there... my
> comment of setting the inner network header twice in inet_gro_complete
> doesn't apply only to vxlan but to other tunneling protocols.

Understood, but my reply about it applying to the inner most hdr in the end
is not limited to vxlan either.

> Also, if
> we really need (why do we? or explained it on the Feb thread) to set
> skb->encapsulation for the sake of TX in a protocol (GRE) gro
> complete, looks a bit fishy to me...

Why does it look fishy? When h/w support sLRO on tunneled pkts
driver will set that bit. So it seems very reasonable for the GRO stack
that supports tunneled pkts to set that bit too.

> but saying this I think brings us
> back to that incomplete discussion [1]  sounds as this needs some
> plumbering... Still, this way or another I understand a regression was
> introduced here and should be fixed.

Yep. I thought we've made reasonable progress on the skb->encapsualtion
even though we can't close all the questions/issues (but we have a real
bug that needs to be fixed here).

Jerry

>
> Or.
>
> [1] http://marc.info/?t=139353642700003&r=1&w=2