Re: [PATCH bpf-next 03/11] bpf: Support inlined/unrolled kfuncs for xdp metadata

From: Stanislav Fomichev <sdf@google.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
	andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
	yhs@fb.com, john.fastabend@gmail.com, kpsingh@kernel.org,
	haoluo@google.com, jolsa@kernel.org,
	David Ahern <dsahern@gmail.com>,
	Willem de Bruijn <willemb@google.com>,
	Jesper Dangaard Brouer <brouer@redhat.com>,
	Anatoly Burakov <anatoly.burakov@intel.com>,
	Alexander Lobakin <alexandr.lobakin@intel.com>,
	Magnus Karlsson <magnus.karlsson@gmail.com>,
	Maryam Tahhan <mtahhan@redhat.com>,
	xdp-hints@xdp-project.net, netdev@vger.kernel.org
Subject: Re: [PATCH bpf-next 03/11] bpf: Support inlined/unrolled kfuncs for xdp metadata
Date: Wed, 16 Nov 2022 12:53:43 -0800	[thread overview]
Message-ID: <CAKH8qBvUtpVA2WgeV0wyNK=sZ1kQV7bnWLKCCDuqM2Anry1weQ@mail.gmail.com> (raw)
In-Reply-To: <20221116124256.04a75fba@kernel.org>

On Wed, Nov 16, 2022 at 12:43 PM Jakub Kicinski <kuba@kernel.org> wrote:
>
> On Mon, 14 Nov 2022 19:02:02 -0800 Stanislav Fomichev wrote:
> > diff --git a/net/core/dev.c b/net/core/dev.c
> > index 117e830cabb0..a2227f4f4a0b 100644
> > --- a/net/core/dev.c
> > +++ b/net/core/dev.c
> > @@ -9258,6 +9258,13 @@ static int dev_xdp_attach(struct net_device *dev, struct netlink_ext_ack *extack
> >                       return -EOPNOTSUPP;
> >               }
> >
> > +             if (new_prog &&
> > +                 new_prog->aux->xdp_kfunc_ndo &&
> > +                 new_prog->aux->xdp_kfunc_ndo != dev->netdev_ops) {
> > +                     NL_SET_ERR_MSG(extack, "Cannot attach to a different target device");
> > +                     return -EINVAL;
> > +             }
>
> This chunk can go up into the large
>
>         if (new_prog) {
>                 ...
>
> list of checks?

Agreed, will move!

> nit: aux->xdp_kfunc_ndo sounds like you're storing the kfunc NDO,
>      not all ndos. Throw in an 's' at the end, or some such?

SG. But I'll most likely replace this xdp_kfunc_ndo with something
like xdp_netdev and to add proper refcounting.