Re: [PATCH resend] virtio_console: Free buffers from out-queue upon close

[Amit Shah <amit.shah@redhat.com>]

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