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From:   Yuri Benditovich <yuri.benditovich@daynix.com>
Date:   Tue, 11 May 2021 22:06:50 +0300
Message-ID: <CAOEp5Of78_c7bGJNSCN7i+xw_N5q=MMGgr8EjnSR9moR+ugExg@mail.gmail.com>
Subject: Re: [PATCH 4/4] tun: indicate support for USO feature
To:     Jason Wang <jasowang@redhat.com>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        "Michael S . Tsirkin" <mst@redhat.com>,
        Network Development <netdev@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        virtualization@lists.linux-foundation.org,
        Yan Vugenfirer <yan@daynix.com>
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On Tue, May 11, 2021 at 11:33 AM Yuri Benditovich
<yuri.benditovich@daynix.com> wrote:
>
> On Tue, May 11, 2021 at 9:50 AM Jason Wang <jasowang@redhat.com> wrote:
> >
> >
> > =E5=9C=A8 2021/5/11 =E4=B8=8B=E5=8D=8812:42, Yuri Benditovich =E5=86=99=
=E9=81=93:
> > > Signed-off-by: Yuri Benditovich <yuri.benditovich@daynix.com>
> > > ---
> > >   drivers/net/tun.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c
> > > index 84f832806313..a35054f9d941 100644
> > > --- a/drivers/net/tun.c
> > > +++ b/drivers/net/tun.c
> > > @@ -2812,7 +2812,7 @@ static int set_offload(struct tun_struct *tun, =
unsigned long arg)
> > >                       arg &=3D ~(TUN_F_TSO4|TUN_F_TSO6);
> > >               }
> > >
> > > -             arg &=3D ~TUN_F_UFO;
> > > +             arg &=3D ~(TUN_F_UFO|TUN_F_USO);
> >
> >
> > It looks to me kernel doesn't use "USO", so TUN_F_UDP_GSO_L4 is a bette=
r
> > name for this
>
> No problem, I can change it in v2
>
>  and I guess we should toggle NETIF_F_UDP_GSO_l4 here?
>
> No, we do not, because this indicates only the fact that the guest can
> send large UDP packets and have them splitted to UDP segments.
>
> >
> > And how about macvtap?
>
> We will check how to do that for macvtap. We will send a separate
> patch for macvtap or ask for advice.
>

I'll add this feature to the tap.c also (AFAIU this will enable the
USO for macvtap).
Please correct me if I'm mistaken.

> >
> > Thanks
> >
> >
> > >       }
> > >
> > >       /* This gives the user a way to test for new features in future=
 by
> >