Re: [RFC PATCH 8/8] virtio: net: Add freeze, restore handlers to support S4

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jul 28, 2011 at 08:05:13PM +0530, Amit Shah wrote:
> Remove all the vqs on hibernation and re-create them after restoring
> from a hibernated image.  This keeps networking working across
> hibernation.
> 
> Signed-off-by: Amit Shah <amit.shah@redhat.com>
> ---
>  drivers/net/virtio_net.c |   51 ++++++++++++++++++++++++++++++++++++++++++++++
>  1 files changed, 51 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 0c7321c..c9aaa8f 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1117,6 +1117,53 @@ static void __devexit virtnet_remove(struct virtio_device *vdev)
>  	free_netdev(vi->dev);
>  }
>  
> +#ifdef CONFIG_PM
> +static int virtnet_freeze(struct virtio_device *vdev)
> +{
> +	struct virtnet_info *vi = vdev->priv;
> +
> +	cancel_delayed_work_sync(&vi->refill);
> +
> +	/* Free unused buffers in both send and recv, if any. */
> +	free_unused_bufs(vi);
> +
> +	vdev->config->del_vqs(vi->vdev);
> +
> +	while (vi->pages)
> +		__free_pages(get_a_page(vi, GFP_KERNEL), 0);
> +
> +	return 0;
> +}
> +
> +static int virtnet_restore(struct virtio_device *vdev)
> +{
> +	struct virtnet_info *vi = vdev->priv;
> +	struct virtqueue *vqs[3];
> +	vq_callback_t *callbacks[] = { skb_recv_done, skb_xmit_done, NULL};
> +	const char *names[] = { "input", "output", "control" };
> +	int nvqs, err;
> +
> +	/* We expect two virtqueues, receive then send,
> +	 * and optionally control. */
> +	nvqs = virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ) ? 3 : 2;
> +
> +	err = vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names);
> +	if (err)
> +		return err;
> +
> +	vi->rvq = vqs[0];
> +	vi->svq = vqs[1];
> +
> +	if (virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ)) {
> +		vi->cvq = vqs[2];
> +	}
> +
> +	/* Last of all, set up some receive buffers. */
> +	try_fill_recv(vi, GFP_KERNEL);

should probably update carrier status too.

> +	return 0;
> +}
> +#endif
> +
>  static struct virtio_device_id id_table[] = {
>  	{ VIRTIO_ID_NET, VIRTIO_DEV_ANY_ID },
>  	{ 0 },
> @@ -1141,6 +1188,10 @@ static struct virtio_driver virtio_net_driver = {
>  	.probe =	virtnet_probe,
>  	.remove =	__devexit_p(virtnet_remove),
>  	.config_changed = virtnet_config_changed,
> +#ifdef CONFIG_PM
> +	.freeze = 	virtnet_freeze,
> +	.restore =	virtnet_restore,
> +#endif
>  };
>  
>  static int __init init(void)
> -- 
> 1.7.6