From: Davide Libenzi <davidel@xmailserver.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
zach.brown@oracle.com, jroberson@chesapeake.net
Subject: Re: [patch] eventfd/kaio integration fix
Date: Wed, 9 Apr 2008 12:19:50 -0700 (PDT) [thread overview]
Message-ID: <Pine.LNX.4.64.0804091217150.7000@alien.or.mcafeemobile.com> (raw)
In-Reply-To: <20080409120812.cad8f173.akpm@linux-foundation.org>
On Wed, 9 Apr 2008, Andrew Morton wrote:
> On Wed, 9 Apr 2008 11:45:47 -0700 (PDT)
> Davide Libenzi <davidel@xmailserver.org> wrote:
>
> > Jeff Roberson discovered a race when using kaio eventfd based
> > notifications. This patch fixes the race by moving the notification inside
> > the spinlocked section of kaio.
>
> Missing information.
>
> What are the consequences of this race, when it occurs?
This was described in the original email. I posted a patch back then
(waiting for Jeff test feedback - that never came), but then I forgot
about it till now:
http://groups.google.com/group/linux.kernel/browse_thread/thread/e814b54c14198616
> > The operation is safe since eventfd
> > spinlock and kaio one are unrelated.
>
> Yes, it's safe from that perspective.
>
> However with this patch applied, we will no longer run eventfd_signal() if
> kiocbIsCancelled(iocb). Convincing is needed, please?
This was the intended behaviour. No event was actually *ready*, so no need
to signal completion of an event.
- Davide
next prev parent reply other threads:[~2008-04-09 19:19 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-09 18:45 Davide Libenzi
2008-04-09 19:08 ` Andrew Morton
2008-04-09 19:19 ` Davide Libenzi [this message]
2008-04-09 19:33 ` Jeff Roberson
2008-04-13 12:29 ` Oliver Pinter
2008-04-13 22:57 ` Davide Libenzi
2008-04-14 17:56 ` Oliver Pinter
2008-04-14 18:02 ` Davide Libenzi
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