Il 18/04/2012 18:10, Michael S. Tsirkin ha scritto:
> On Wed, Apr 18, 2012 at 04:34:12PM +0200, Paolo Bonzini wrote:
>> Il 18/04/2012 16:21, Michael S. Tsirkin ha scritto:
>>>> @@ -1872,6 +1864,8 @@ static int virtcons_restore(struct virtio_device *vdev)
>>>> list_for_each_entry(port, &portdev->ports, list) {
>>>> port->in_vq = portdev->in_vqs[port->id];
>>>> port->out_vq = portdev->out_vqs[port->id];
>>>> + port->in_vq->vdev_priv = port;
>>>> + port->out_vq->vdev_priv = port;
>>>>
>>>> fill_queue(port->in_vq, &port->inbuf_lock);
>>>>
>>>
>>> Let's add an API to set this pointer.
>>> Document that you must not set it after
>>> probe/restore returned.
>>
>> Why?
>
> How would you prevent races if you do?
With some lock in the driver. It's private to the driver, so the driver
decides how to synchronize access.
>>>> * @priv: a pointer for the virtqueue implementation to use.
>>>> */
>>>> struct virtqueue {
>>>> @@ -21,6 +22,7 @@ struct virtqueue {
>>>> void (*callback)(struct virtqueue *vq);
>>>> const char *name;
>>>> struct virtio_device *vdev;
>>>> + void *vdev_priv;
>>>> void *priv;
>>>
>>> The name is confusing: it seems to imply it's a device pointer.
>>
>> ... it's private to the driver that owns vdev, hence the name.
>
> I own a car but I'm not called Michael Car :)
> driver_priv might be ok too. unfortunately virtio-pci
> is also a driver so it can be misunderstood.
Yes. Is fixing the comment and keeping the vdev_priv name ok with you?
> devices should dominate. ring is an implementation detail.
Ring came first, ring gets the nice name. :)
Paolo
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