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References: <20190624215824.118783-1-allanzhang@google.com>
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From:   Song Liu <liu.song.a23@gmail.com>
Date:   Mon, 24 Jun 2019 16:10:59 -0700
Message-ID: <CAPhsuW40c=CTdTo9YUbyj3AAL+A37TX1-Bty267bCYOaThJJ7w@mail.gmail.com>
Subject: Re: [PATCH] bpf: Allow bpf_skb_event_output for a few prog types
To:     allanzhang <allanzhang@google.com>
Cc:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        "David S. Miller" <davem@davemloft.net>,
        Networking <netdev@vger.kernel.org>, bpf <bpf@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
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On Mon, Jun 24, 2019 at 3:08 PM allanzhang <allanzhang@google.com> wrote:
>
> Software event output is only enabled by a few prog types right now (TC,
> LWT out, XDP, sockops). Many other skb based prog types need
> bpf_skb_event_output to produce software event.
>
> Added socket_filter, cg_skb, sk_skb prog types to generate sw event.
>
> Test bpf code is generated from code snippet:
>
> struct TMP {
>     uint64_t tmp;
> } tt;
> tt.tmp = 5;
> bpf_perf_event_output(skb, &connection_tracking_event_map, 0,
>                       &tt, sizeof(tt));
> return 1;
>
> the bpf assembly from llvm is:
>        0:       b7 02 00 00 05 00 00 00         r2 = 5
>        1:       7b 2a f8 ff 00 00 00 00         *(u64 *)(r10 - 8) = r2
>        2:       bf a4 00 00 00 00 00 00         r4 = r10
>        3:       07 04 00 00 f8 ff ff ff         r4 += -8
>        4:       18 02 00 00 00 00 00 00 00 00 00 00 00 00 00 00    r2 = 0ll
>        6:       b7 03 00 00 00 00 00 00         r3 = 0
>        7:       b7 05 00 00 08 00 00 00         r5 = 8
>        8:       85 00 00 00 19 00 00 00         call 25
>        9:       b7 00 00 00 01 00 00 00         r0 = 1
>       10:       95 00 00 00 00 00 00 00         exit
>
> Patch 1 is enabling code.
> Patch 2 is fullly covered selftest code.
>
> Signed-off-by: allanzhang <allanzhang@google.com>

A few logistics issues:

1. The patch should be sent as a set, as
   [PATCH bpf-next 0/2] ...
   [PATCH bpf-next 1/2] ...
   [PATCH bpf-next 2/2] ...

2. You need to specify which tree this is targeting. In this case, bpf-next.
3. Please use different commit log for each patch.
4. No need for Signed-off-by in the cover letter.

Please resubmit. And generate the patches with git command similar to
the following:

git format-patch --cover-leter --subject_prefix "PATCH bpf-next v2" HEAD~2

Thanks,
Song