netdev - Re: [PATCH bpf-next 6/6] bpf: BPF_PROG_TYPE_CGROUP_{SKB,SOCK,SOCK

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Date:   Mon, 17 Dec 2018 10:16:31 -0800
From:   Stanislav Fomichev <sdf@...ichev.me>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>
Cc:     Stanislav Fomichev <sdf@...gle.com>,
        Network Development <netdev@...r.kernel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Daniel Borkmann <daniel@...earbox.net>,
        Edward Cree <ecree@...arflare.com>,
        Quentin Monnet <quentin.monnet@...ronome.com>
Subject: Re: [PATCH bpf-next 6/6] bpf:
 BPF_PROG_TYPE_CGROUP_{SKB,SOCK,SOCK_ADDR} require cgroups enabled

On 12/15, Stanislav Fomichev wrote:
> On 12/14, Alexei Starovoitov wrote:
> > On Thu, Dec 13, 2018 at 11:03 AM Stanislav Fomichev <sdf@...gle.com> wrote:
> > >
> > > There is no way to exercise appropriate attach points without cgroups
> > > enabled. This lets test_verifier correctly skip tests for these
> > > prog_types if kernel was compiled without BPF cgroup support.
> > >
> > > Signed-off-by: Stanislav Fomichev <sdf@...gle.com>
> > > ---
> > >  include/linux/bpf_types.h |  2 ++
> > >  net/core/filter.c         | 18 ++++++++++++++++++
> > >  2 files changed, 20 insertions(+)
> > >
> > > diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
> > > index 44d9ab4809bd..08bf2f1fe553 100644
> > > --- a/include/linux/bpf_types.h
> > > +++ b/include/linux/bpf_types.h
> > > @@ -6,9 +6,11 @@ BPF_PROG_TYPE(BPF_PROG_TYPE_SOCKET_FILTER, sk_filter)
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_SCHED_CLS, tc_cls_act)
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_SCHED_ACT, tc_cls_act)
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_XDP, xdp)
> > > +#ifdef CONFIG_CGROUP_BPF
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SKB, cg_skb)
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SOCK, cg_sock)
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_CGROUP_SOCK_ADDR, cg_sock_addr)
> > > +#endif
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_IN, lwt_in)
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_OUT, lwt_out)
> > >  BPF_PROG_TYPE(BPF_PROG_TYPE_LWT_XMIT, lwt_xmit)
> > > diff --git a/net/core/filter.c b/net/core/filter.c
> > > index f9348806e843..6a390e519431 100644
> > > --- a/net/core/filter.c
> > > +++ b/net/core/filter.c
> > > @@ -5315,6 +5315,7 @@ bpf_base_func_proto(enum bpf_func_id func_id)
> > >         }
> > >  }
> > >
> > > +#ifdef CONFIG_CGROUP_BPF
> > >  static const struct bpf_func_proto *
> > >  sock_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > >  {
> > > @@ -5364,6 +5365,7 @@ sock_addr_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > >                 return bpf_base_func_proto(func_id);
> > >         }
> > >  }
> > > +#endif
> > >
> > >  static const struct bpf_func_proto *
> > >  sk_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > > @@ -5382,6 +5384,7 @@ sk_filter_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > >         }
> > >  }
> > >
> > > +#ifdef CONFIG_CGROUP_BPF
> > >  static const struct bpf_func_proto *
> > >  cg_skb_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog)
> > 
> > I don't think it's worth uglifying the code like this.
> > I prefer to leave it as-is.
> Sure, up to you. I mostly included it for completeness sake. I tested on
> two configs: the first one is allyesbpf, the second one is minimal set
> of bpf features and no cgroups.
> 
> (For my usecase cgroups and hence these prog types are always enabled,
> so it doesn't matter for me).
On a second thought, I think I can just have a single ifdef in the
bpf_types.h and don't touch the C file. That should have the same effect
without too much ugliness in the C file. I'll send a v2 shortly.