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From: Jamie Lokier <jamie@shareable.org>
To: Davide Libenzi <davidel@xmailserver.org>
Cc: Ben Mansell <ben@zeus.com>, Steven Dake <sdake@mvista.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Is POLLHUP an input-only or bidirectional condition? (was: epoll reporting events when it hasn't been asked to)
Date: Sun, 4 Apr 2004 03:08:51 +0100	[thread overview]
Message-ID: <20040404020851.GB7074@mail.shareable.org> (raw)
In-Reply-To: <Pine.LNX.4.44.0404031723570.2710-100000@bigblue.dev.mdolabs.com>

Davide Libenzi wrote:
> > Btw, I notice epoll never reports POLLNVAL.  Is that correct?
> 
> Yep, epoll does not allow you to push an invalid/unopen file descriptor 
> inside the set. So you get an EBADF from epoll_ctl().

A comment in eventpoll.c says:

 * This semaphore is acquired by ep_free() during the epoll file
 * cleanup path and it is also acquired by eventpoll_release()
 * if a file has been pushed inside an epoll set and it is then
 * close()d without a previous call toepoll_ctl(EPOLL_CTL_DEL).

I.e. implying that the final close() is possible while it's registered.
(Btw, a function called eventpoll_release() doesn't exist).

What happens when a file descriptor is closed while it is inside the set?

I guess it's simply dropped from the set, is that right?

-- Jamie

  reply	other threads:[~2004-04-04  2:09 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-04-01 18:25 epoll reporting events when it hasn't been asked to Ben Mansell
2004-04-01 19:28 ` Davide Libenzi
2004-04-01 23:29   ` Steven Dake
2004-04-02  9:04     ` Ben Mansell
2004-04-02 15:22       ` Davide Libenzi
2004-04-02 18:40         ` Is POLLHUP an input-only or bidirectional condition? (was: epoll reporting events when it hasn't been asked to) Jamie Lokier
2004-04-03 12:19           ` Is POLLHUP an input-only or bidirectional condition? Richard Kettlewell
2004-04-03 21:44           ` Is POLLHUP an input-only or bidirectional condition? (was: epoll reporting events when it hasn't been asked to) Davide Libenzi
2004-04-03 22:35             ` Jamie Lokier
2004-04-04  1:28               ` Davide Libenzi
2004-04-04  2:08                 ` Jamie Lokier [this message]
2004-04-04  2:49                   ` Davide Libenzi
2004-04-04 18:51               ` Ben Mansell
2004-04-04 19:41                 ` Davide Libenzi
2004-04-04 20:24                 ` Jamie Lokier
2004-04-14 17:59         ` epoll reporting events when it hasn't been asked to Dirk Morris
2004-04-14 19:39           ` Jamie Lokier
2004-04-14 20:21             ` Dirk Morris
2004-04-14 21:48               ` Jamie Lokier

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