Re: [PATCH] epoll: add exclusive wakeups flag

[Michael Kerrisk (man-pages)]

>> By the way, in the code you have
>>
>>         case EPOLL_CTL_MOD:
>>                 if (epi) {
>>                         if (!(epi->event.events & EPOLLEXCLUSIVE)) {
>>                                 epds.events |= POLLERR | POLLHUP;
>>                                 error = ep_modify(ep, epi, &epds);
>>                         }
>>
>> I think the "if" here is redundant. IIUC, earlier in the code you
>> disallow EPOLL_CTL_MOD with EPOLLEXCLUSIVE.
>>
>> Cheers,
>>
>> Michael
>>
>>
>
> Hi Michael,
>
> So the previous check ensures that you can not add the EPOLLEXCLUSIVE
> flag to the events via an EPOLL_CTL_MOD operation, where EPOLLEXCLUSIVE
> may not be the existing events set. While this check here ensure you
> can't modify an existing set that already has the EPOLLEXCLUSIVE flag.

Hmmm - I misread the code, itr seems :-/. Could you please carefully
check the man page text I sent earlier in this thread. Maybe I
injected some errors into the text.

Thanks,

Michael

-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/