From mboxrd@z Thu Jan  1 00:00:00 1970
From: Gleb Natapov <gleb@redhat.com>
Subject: Re: [PATCH 0/2] eventfd: new EFD_STATE flag
Date: Mon, 11 Jan 2010 11:01:27 +0200
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Cc: Davide Libenzi <davidel@xmailserver.org>,
	Avi Kivity <avi@redhat.com>, kvm@vger.kernel.org
To: "Michael S. Tsirkin" <mst@redhat.com>
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On Thu, Jan 07, 2010 at 12:36:01PM +0200, Michael S. Tsirkin wrote:
> Or if I do it the other way:
> 		remove_wait_queue(irqfd->wqh, &irqfd->wait);
> 	->
> 		eventfd_read_ctx(irqfd->eventfd, &ucnt);
> 
> now, if device signals eventfd at point marked by ->,
> it will not be sent but counter will be cleared,
> so we will loose a message.
> 
May be I am missing something here, but why doing it like that is a
problem? Event delivery races with interrupt masking so making masking
succeed before event delivery is OK. Event generation is asynchronous
anyway and could have happened jiffy latter anyway.

--
			Gleb.