Date: Tue, 05 Dec 2017 15:11:59 -0500 (EST)
Message-Id: <20171205.151159.1781485937410298333.davem@davemloft.net>
To: laoar.shao@gmail.com
Cc: songliubraving@fb.com, marcelo.leitner@gmail.com, kuznet@ms2.inr.ac.ru,
        yoshfuji@linux-ipv6.org, rostedt@goodmis.org, bgregg@netflix.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 net-next] net/tcp: trace all TCP/IP state transition
 with tcp_set_state tracepoint
From: David Miller <davem@davemloft.net>
In-Reply-To: <1512483162-5557-1-git-send-email-laoar.shao@gmail.com>
References: <1512483162-5557-1-git-send-email-laoar.shao@gmail.com>
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From: Yafang Shao <laoar.shao@gmail.com>
Date: Tue,  5 Dec 2017 14:12:42 +0000

>  }
>  
> +/* For tcp_set_state tracepoint */
> +void sk_state_store(struct sock *sk, int newstate);
> +
>  void sock_enable_timestamp(struct sock *sk, int flag);
>  int sock_get_timestamp(struct sock *, struct timeval __user *);
>  int sock_get_timestampns(struct sock *, struct timespec __user *);
 ...
> --- a/net/ipv4/tcp.c
> +++ b/net/ipv4/tcp.c
> @@ -2036,6 +2036,18 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int nonblock,
>  }
>  EXPORT_SYMBOL(tcp_recvmsg);
>  
> +void sk_state_store(struct sock *sk, int newstate)
> +{
> +	trace_tcp_set_state(sk, sk->sk_state, newstate);
> +	__sk_state_store(sk, newstate);
> +}
> +

Please do not define a sock generic function in the TCP protocol code.

If it belongs in TCP and is only used by TCP, give is a tcp specific
name prefix rather than a generic sk_ one.

This is even more ugly because I see that inet_connection_sock.c and
inet_hashtables.c uses this thing too.  Which means that DCCP sockets
will trigger this tracepoint.

inet_connection_sock.c and inet_hashtables.c are not guaranteed to
operate on only TCP sockets, and you must make amends to handle that
properly.

Thanks.