From: Andrii Nakryiko <andrii.nakryiko@gmail.com>
To: David Ahern <dsahern@gmail.com>
Cc: "David Ahern" <dsahern@kernel.org>,
Networking <netdev@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Jakub Kicinski" <kuba@kernel.org>,
"Jesper Dangaard Brouer" <brouer@redhat.com>,
"Toke Høiland-Jørgensen" <toke@redhat.com>,
"Daniel Borkmann" <daniel@iogearbox.net>,
"john fastabend" <john.fastabend@gmail.com>,
"Alexei Starovoitov" <ast@kernel.org>,
"Martin Lau" <kafai@fb.com>, "Song Liu" <songliubraving@fb.com>,
"Yonghong Song" <yhs@fb.com>, "Andrii Nakryiko" <andriin@fb.com>
Subject: Re: [PATCH v2 bpf-next 2/5] bpf: Add support to attach bpf program to a devmap entry
Date: Thu, 28 May 2020 15:54:16 -0700 [thread overview]
Message-ID: <CAEf4BzZft4TV75RbgBgPfu5Ps3b+h8dM6jbJQ_3_ue=EmSq0rQ@mail.gmail.com> (raw)
In-Reply-To: <191ba79f-3aeb-718c-644e-bd2cc539dc60@gmail.com>
On Thu, May 28, 2020 at 3:40 PM David Ahern <dsahern@gmail.com> wrote:
>
> On 5/28/20 1:01 AM, Andrii Nakryiko wrote:
> >
> > Please cc bpf@vger.kernel.org in the future for patches related to BPF
> > in general.
>
> added to my script
>
> >
> >> include/linux/bpf.h | 5 +++
> >> include/uapi/linux/bpf.h | 5 +++
> >> kernel/bpf/devmap.c | 79 +++++++++++++++++++++++++++++++++-
> >> net/core/dev.c | 18 ++++++++
> >> tools/include/uapi/linux/bpf.h | 5 +++
> >> 5 files changed, 110 insertions(+), 2 deletions(-)
> >>
> >
> > [...]
> >
> >>
> >> +static struct xdp_buff *dev_map_run_prog(struct net_device *dev,
> >> + struct xdp_buff *xdp,
> >> + struct bpf_prog *xdp_prog)
> >> +{
> >> + u32 act;
> >> +
> >> + act = bpf_prog_run_xdp(xdp_prog, xdp);
> >> + switch (act) {
> >> + case XDP_DROP:
> >> + fallthrough;
> >
> > nit: I don't think fallthrough is necessary for cases like:
> >
> > case XDP_DROP:
> > case XDP_PASS:
> > /* do something */
> >
> >> + case XDP_PASS:
> >> + break;
> >> + default:
> >> + bpf_warn_invalid_xdp_action(act);
> >> + fallthrough;
> >> + case XDP_ABORTED:
> >> + trace_xdp_exception(dev, xdp_prog, act);
> >> + act = XDP_DROP;
> >> + break;
> >> + }
> >> +
> >> + if (act == XDP_DROP) {
> >> + xdp_return_buff(xdp);
> >> + xdp = NULL;
> >
> > hm.. if you move XDP_DROP case to after XDP_ABORTED and do fallthrough
> > from XDP_ABORTED, you won't even need to override act and it will just
> > handle all the cases, no?
> >
> > switch (act) {
> > case XDP_PASS:
> > return xdp;
> > default:
> > bpf_warn_invalid_xdp_action(act);
> > fallthrough;
> > case XDP_ABORTED:
> > trace_xdp_exception(dev, xdp_prog, act);
> > fallthrough;
> > case XDP_DROP:
> > xdp_return_buff(xdp);
> > return NULL;
> > }
> >
> > Wouldn't this be simpler?
> >
>
> Switched it to this which captures your intent with a more traditional
> return location.
>
> act = bpf_prog_run_xdp(xdp_prog, xdp);
> switch (act) {
> case XDP_PASS:
> return xdp;
> case XDP_DROP:
> break;
> default:
> bpf_warn_invalid_xdp_action(act);
> fallthrough;
> case XDP_ABORTED:
> trace_xdp_exception(dev, xdp_prog, act);
> break;
> }
>
> xdp_return_buff(xdp);
> return NULL;
looks good as well, thanks
next prev parent reply other threads:[~2020-05-28 22:54 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-28 0:14 [PATCH v2 bpf-next 0/5] bpf: Add support for XDP programs in DEVMAP entries David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 1/5] devmap: Formalize map value as a named struct David Ahern
2020-05-28 7:01 ` Andrii Nakryiko
2020-05-28 22:37 ` David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 2/5] bpf: Add support to attach bpf program to a devmap entry David Ahern
2020-05-28 7:01 ` Andrii Nakryiko
2020-05-28 22:40 ` David Ahern
2020-05-28 22:54 ` Andrii Nakryiko [this message]
2020-05-28 8:54 ` Toke Høiland-Jørgensen
2020-05-28 0:14 ` [PATCH v2 bpf-next 3/5] xdp: Add xdp_txq_info to xdp_buff David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 4/5] libbpf: Add SEC name for xdp programs attached to device map David Ahern
2020-05-28 7:04 ` Andrii Nakryiko
2020-05-28 22:49 ` David Ahern
2020-05-28 0:14 ` [PATCH v2 bpf-next 5/5] selftest: Add tests for XDP programs in devmap entries David Ahern
2020-05-28 7:08 ` Andrii Nakryiko
2020-05-28 10:25 ` Jesper Dangaard Brouer
2020-05-28 22:56 ` David Ahern
2020-05-28 22:54 ` David Ahern
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