From: David Ahern <dsahern@gmail•com>
To: Andrii Nakryiko <andrii.nakryiko@gmail•com>,
David Ahern <dsahern@kernel•org>
Cc: 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 16:40:06 -0600 [thread overview]
Message-ID: <191ba79f-3aeb-718c-644e-bd2cc539dc60@gmail.com> (raw)
In-Reply-To: <CAEf4BzYZSPdGH+RXp+kHfWnGGLRuiP=ho9oMsSf7RsYWyeNk0g@mail.gmail.com>
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;
next prev parent reply other threads:[~2020-05-28 22:40 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 [this message]
2020-05-28 22:54 ` Andrii Nakryiko
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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