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);
...
> > static void __exit fini(void)
> > {
> > + reclaim_dma_bufs();
>
> Hmm, you didn't protect it here anyway...
>
> Cheers,
> Rusty.
Amit
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