Re: [patch] epoll - send POLLHUP on ->release

[Davide Libenzi]

On Wed, 3 Jun 2009, Andrew Morton wrote:

> On Wed, 03 Jun 2009 15:20:26 -0400
> Gregory Haskins <ghaskins@xxxxxxxxxx> wrote:
> 
> > Davide Libenzi wrote:
> > > The following patch allows waiters to be notified about the eventfd file* 
> > > going away, and give them a change to unregister from the wait queue.
> > > This is turn allows eventfd users to use the eventfd file* w/out 
> > > holding a live reference to it.
> > > After the eventfd user callbacks returns, any usage of the eventfd file* 
> > > should be dropped. The eventfd user callback can acquire sleepy locks 
> > > since it is invoked lockless.
> > >
> > >
> > >
> > > Signed-off-by: Davide Libenzi <davidel@xxxxxxxxxxxxxxx>
> > >   
> > 
> > Tested-by: Gregory Haskins <ghaskins@xxxxxxxxxx>
> 
> Confused.  Did you test this with some new kernel patch, or with some
> existing kernel code?
> 
> If the latter, what code are we talking about here and what was the test
> case and what went wrong when using the current mainline
> implementation?

Andrew, this is not related to a bug in mainline. It's an helper for 
IRQFD, that allows them to not hold reference counts over the underlying 
eventfd.
I believe this has been tested using Gregory's IRQFD code.



- Davide


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