From mboxrd@z Thu Jan  1 00:00:00 1970
From: Amit Shah <amit.shah@redhat.com>
Subject: Re: [PATCH resend] virtio_console: Free buffers from out-queue upon
	close
Date: Thu, 8 Nov 2012 09:59:13 +0100
Message-ID: <20121108085913.GA31962@amit.redhat.com>
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To: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>, sjur@brendeland.net, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>, sjur.brandeland@stericsson.com
List-Id: virtualization@lists.linuxfoundation.org

On (Thu) 08 Nov 2012 [10:28:53], Rusty Russell wrote:
> sjur.brandeland@stericsson.com writes:
> =

> > From: Sjur Br=E6ndeland <sjur.brandeland@stericsson.com>
> >
> > Free pending output buffers from the virtio out-queue when
> > host has acknowledged port_close. Also removed WARN_ON()
> > in remove_port_data().
> >
> > Signed-off-by: Sjur Br=E6ndeland <sjur.brandeland@stericsson.com>
> > ---
> >
> > Resending, this time including a proper "Subject"...
> > --
> >
> > Hi Amit,
> >
> > Note: This patch is compile tested only. I have done the removal
> > of buffers from out-queue in handle_control_message()
> > when host has acked the close request. This seems less
> > racy than doing it in the release function.
> =

> This confuses me... why are we doing this in case
> VIRTIO_CONSOLE_PORT_OPEN:?
> =

> We can't pull unconsumed buffers out of the ring when the other side may
> still access it, and this seems to be doing that.

Yes -- and it's my fault; I asked Sjur to do that in the close fops
function.

We should only do this in the port remove case (unplug or device
remove) -- so the original patch, with just the WARN_ON removed is the
right way.

I'll send the revised 3/3 patch for you.

		Amit