On Fri, Mar 09, 2018 at 02:50:33PM +0800, Jason Wang wrote:
> We get pointer ring from the exported sock, this means we should keep
> rx_ring and vq->private synced during both vq stop and backend set,
> otherwise we may see stale rx_ring.
>
> Fixes: c67df11f6e480 ("vhost_net: try batch dequing from skb array")
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
> drivers/vhost/net.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 60f1080..efb9306 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -973,6 +973,7 @@ static struct socket *vhost_net_stop_vq(struct vhost_net *n,
> vhost_net_disable_vq(n, vq);
> vq->private_data = NULL;
> vhost_net_buf_unproduce(nvq);
> + nvq->rx_ring = NULL;
> mutex_unlock(&vq->mutex);
> return sock;
> }
> @@ -1162,14 +1163,14 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
> vhost_net_disable_vq(n, vq);
> vq->private_data = sock;
> vhost_net_buf_unproduce(nvq);
> - if (index == VHOST_NET_VQ_RX)
> - nvq->rx_ring = get_tap_ptr_ring(fd);
> r = vhost_vq_init_access(vq);
> if (r)
> goto err_used;
> r = vhost_net_enable_vq(n, vq);
> if (r)
> goto err_used;
> + if (index == VHOST_NET_VQ_RX)
> + nvq->rx_ring = get_tap_ptr_ring(fd);
>
> oldubufs = nvq->ubufs;
> nvq->ubufs = ubufs;
> --
> 2.7.4
