Re: [PATCH v5 net-next] net/tcp: trace all TCP/IP state transition with tcp_set_state tracepoint

[David Miller]

From: Yafang Shao <laoar.shao@xxxxxxxxx>
Date: Fri, 8 Dec 2017 23:50:44 +0800

> 2017-12-08 23:42 GMT+08:00 David Miller <davem@xxxxxxxxxxxxx>:
>> From: Yafang Shao <laoar.shao@xxxxxxxxx>
>> Date: Fri, 8 Dec 2017 11:40:23 +0800
>>
>>> It will looks like these,
>>>
>>>     if (sk->sk_protocol == IPPROTO_TCP)
>>>         __tcp_set_state(newsk, TCP_SYN_RECV);
>>>     else
>>>         newsk->sk_state = TCP_SYN_RECV;
>>>
>>>
>>>     if (sk->sk_protocol == IPPROTO_TCP)
>>>           __tcp_set_state(sk, TCP_CLOSE);
>>>     else
>>>           sk->sk_state = TCP_CLOSE;
>>>
>>>     if (sk->sk_protocol == IPPROTO_TCP)
>>>           tcp_state_store(sk,  state);
>>>     else
>>>           sk_state_store(sk, state);
>>>
>>>
>>> Some redundant code.
>>>
>>> IMO, put these similar code into a wrapper is more nice.
>>
>> I think this discussion and how ugly this is getting shows that
>> tracing the state transitions of a socket is perhaps not best as a TCP
>> specific feature.
> 
> Do you mean that tcp_set_state tracepoint should be replaced with
> sk_set_state tracepoint and move that tracepoint to
> trace/events/sock.h ?

Yes, something like that.

It will avoid all of these protocol specific checks and weird
dependencies.