Re: [PATCH v2 mptcp-net 2/2] mptcp: fix duplicate reset on fastclose

[Paolo Abeni <pabeni@redhat.com>]

On 11/11/25 7:14 AM, Matthieu Baerts wrote:
> 11 Nov 2025 02:59:28 Geliang Tang <geliang@kernel.org>:
>> On Fri, 2025-11-07 at 08:23 +0100, Paolo Abeni wrote:
>>> @@ -2448,7 +2447,7 @@ static void __mptcp_subflow_disconnect(struct
>>> sock *ssk,
>>>                        unsigned int flags)
>>
>> nit:
>>
>> The 3rd argument "flags" of __mptcp_subflow_disconnect is useless now.
>> We can drop it.
> 
> I don't think it is useless: __mptcp_close_ssk() is still called with either
> the push flag or no flag (0).
> 
> Because this patch is for net, we should avoid unnecessary modifications:
> we should not change the type or the name of the function argument for
> "cosmetic" reasons.

FWIW, I agree with Mat.

>>> @@ -2511,20 +2510,13 @@ static void __mptcp_close_ssk(struct sock
>>> *sk, struct sock *ssk,
>>>     if (dispose_it)
>>>         list_del(&subflow->node);
>>>  
>>> -   if ((flags & MPTCP_CF_FASTCLOSE) &&
>>> !__mptcp_check_fallback(msk)) {
>>> -       /* be sure to force the tcp_close path
>>> -        * to generate the egress reset
>>> -        */
>>> -       ssk->sk_lingertime = 0;
>>> -       sock_set_flag(ssk, SOCK_LINGER);
>>> -       subflow->send_fastclose = 1;
>>> -   }
>>> +   if (subflow->send_fastclose && ssk->sk_state != TCP_CLOSE)
>>> +       tcp_set_state(ssk, TCP_CLOSE);
>>>  
>>>     need_push = (flags & MPTCP_CF_PUSH) &&
>>> __mptcp_retransmit_pending_data(sk);
>>>     if (!dispose_it) {
>>>         __mptcp_subflow_disconnect(ssk, subflow, flags);
>>>         release_sock(ssk);
>>> -
> 
> (This line should not be removed but this can be fixed when applying the patch.)

Thanks!

/P