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From:   =?UTF-8?B?6L+Q6L6J5bSU?= <cuiyunhui@bytedance.com>
Date:   Tue, 10 Jan 2023 16:58:36 +0800
Message-ID: <CAEEQ3w=ZyzamCKtYA76EksYiHM=-=mS5jaWwH5mk9nz-T0up4w@mail.gmail.com>
Subject: Re: [External] Re: [PATCH v4] sock: add tracepoint for send recv length
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Eric Dumazet <edumazet@google.com>, mhiramat@kernel.org,
        davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com,
        kuniyu@amazon.com, xiyou.wangcong@gmail.com,
        duanxiongchun@bytedance.com, linux-kernel@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org, netdev@vger.kernel.org,
        dust.li@linux.alibaba.com
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On Mon, Jan 9, 2023 at 11:39 PM Steven Rostedt <rostedt@goodmis.org> wrote:

>
> But looking at this tracepoint again, I see a issue that can help with the
> dereferencing.
>
> Why is family and protocol passed in?
>
> +       trace_sock_send_length(sock->sk, sock->sk->sk_family,
> +                              sock->sk->sk_protocol, ret, 0);
>
>
> Where the TP_fast_assign() is:
>
> +       TP_fast_assign(
> +               __entry->sk = sk;
> +               __entry->family = sk->sk_family;
> +               __entry->protocol = sk->sk_protocol;
> +               __entry->length = ret > 0 ? ret : 0;
> +               __entry->error = ret < 0 ? ret : 0;
> +               __entry->flags = flags;
> +       ),
>
> The family and protocol is taken from the sk, and not the parameters. I bet
> dropping those would help.
>
> -- Steve
>

Many thanks to Eric and Steven for your discussions and suggestions, I
will update on v5.


Thanks,
Yunhui