On (Fri) 02 Nov 2012 [09:52:08], Rusty Russell wrote:
> Amit Shah <amit.shah@xxxxxxxxxx> writes:
> > On (Tue) 23 Oct 2012 [12:17:49], Rusty Russell wrote:
> >> sjur.brandeland@xxxxxxxxxxxxxx writes:
> >> > From: Sjur Brændeland <sjur.brandeland@xxxxxxxxxxxxxx>
> >
> >> > @@ -1415,7 +1524,16 @@ static void remove_port_data(struct port *port)
> >> >
> >> > /* Remove buffers we queued up for the Host to send us data in. */
> >> > while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
> >> > - free_buf(buf);
> >> > + free_buf(buf, true);
> >> > +
> >> > + /*
> >> > + * Remove buffers from out queue for rproc-serial. We cannot afford
> >> > + * to leak any DMA mem, so reclaim this memory even if this might be
> >> > + * racy for the remote processor.
> >> > + */
> >> > + if (is_rproc_serial(port->portdev->vdev))
> >> > + while ((buf = virtqueue_detach_unused_buf(port->out_vq)))
> >> > + free_buf(buf, true);
> >> > }
> >>
> >> This seems wrong; either this is needed even if !is_rproc_serial(), or
> >> it's not necessary as the out_vq is empty.
> >>
> >> Every path I can see has the device reset (in which case the queues
> >> should not be active), or we got a VIRTIO_CONSOLE_PORT_REMOVE event (in
> >> which case, the same).
> >>
> >> I think we can have non-blocking writes which could leave buffers in
> >> out_vq: Amit?
> >
> > Those get 'reclaimed' just above this hunk:
> >
> >
> > static void remove_port_data(struct port *port)
> > {
> > struct port_buffer *buf;
> >
> > /* Remove unused data this port might have received. */
> > discard_port_data(port);
> >
> > reclaim_consumed_buffers(port);
> >
> > /* Remove buffers we queued up for the Host to send us data in. */
> > while ((buf = virtqueue_detach_unused_buf(port->in_vq)))
> > free_buf(buf, true);
>
> No, that's pending input buffers, not output buffers.
You're right. Nice catch.
Sjur, can you remove the WARN_ON in your latest series, even generic
ports may have buffers in the outq.
It'll also need to be done in the port_fops_release() function. Let
me know if you prefer I send a patch instead.
Thanks,
Amit
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