Re: [PATCH v4 4/7] tcp, flow: Replace per-connection in_epoll flag with threadnb in flow_common

[Laurent Vivier <lvivier@redhat.com>]

On 20/10/2025 03:34, David Gibson wrote:
>> @@ -570,7 +572,8 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
>>   		}
>>   		conn->timer = fd;
>>   
>> -		if (epoll_ctl(c->epollfd, EPOLL_CTL_ADD, conn->timer, &ev)) {
>> +		if (epoll_ctl(flow_epollfd(&conn->f), EPOLL_CTL_ADD,
>> +			      conn->timer, &ev)) {
> Possibly a question for an earlier patch, but is there a reason we
> can't use epoll_add() here?
> 

Yes, the fd we use in epoll_ctl() and the fd stored in ref are not the same.

The fd in ref is conn->sock (epoll_add() takes fd from ref) but in epoll_ctl() we add 
conn->timer (the fd from timerfd_create()).

Thanks,
Laurent