Re: [PATCH net] bonding: do not report NETDEV_XDP_ACT_XSK_ZEROCOPY

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On Mon, 5 Feb 2024 at 14:08, Toke Høiland-Jørgensen <toke@redhat.com> wrote:
> >
> > Magnus Karlsson <magnus.karlsson@gmail.com> writes:
> >
> > > From: Magnus Karlsson <magnus.karlsson@intel.com>
> > >
> > > Do not report the XDP capability NETDEV_XDP_ACT_XSK_ZEROCOPY as the
> > > bonding driver does not support XDP and AF_XDP in zero-copy mode even
> > > if the real NIC drivers do.
> > >
> > > Fixes: cb9e6e584d58 ("bonding: add xdp_features support")
> > > Reported-by: Prashant Batra <prbatra.mail@gmail.com>
> > > Link: https://lore.kernel.org/all/CAJ8uoz2ieZCopgqTvQ9ZY6xQgTbujmC6XkMTamhp68O-h_-rLg@mail.gmail.com/T/
> > > Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
> > > ---
> > >  drivers/net/bonding/bond_main.c | 6 +++++-
> > >  1 file changed, 5 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
> > > index 4e0600c7b050..79a37bed097b 100644
> > > --- a/drivers/net/bonding/bond_main.c
> > > +++ b/drivers/net/bonding/bond_main.c
> > > @@ -1819,6 +1819,8 @@ void bond_xdp_set_features(struct net_device *bond_dev)
> > >       bond_for_each_slave(bond, slave, iter)
> > >               val &= slave->dev->xdp_features;
> > >
> > > +     val &= ~NETDEV_XDP_ACT_XSK_ZEROCOPY;
> > > +
> > >       xdp_set_features_flag(bond_dev, val);
> > >  }
> > >
> > > @@ -5910,8 +5912,10 @@ void bond_setup(struct net_device *bond_dev)
> > >               bond_dev->features |= BOND_XFRM_FEATURES;
> > >  #endif /* CONFIG_XFRM_OFFLOAD */
> > >
> > > -     if (bond_xdp_check(bond))
> > > +     if (bond_xdp_check(bond)) {
> > >               bond_dev->xdp_features = NETDEV_XDP_ACT_MASK;
> > > +             bond_dev->xdp_features &= ~NETDEV_XDP_ACT_XSK_ZEROCOPY;
> > > +     }
> >
> > Shouldn't we rather drop this assignment completely? It makes no sense
> > to default to all features, it should default to none...
> 
> Good point. Seems the bond device defaults to supporting everything
> before a device is bonded to it, but I might have misunderstood
> something. Lorenzo, could you enlighten us please?

ack, I agree we can get rid of it since the xdp features will be calculated
again as soon as a new device is added to the bond.

Regards,
Lorenzo

> 
> Thanks: Magnus
> 
> > -Toke
> >

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