Re: [PATCH net 2/4] virtio-net: correctly transmit XDP buff after linearizing

Michael S. Tsirkin
2018-05-21T15:03:55Z

On Mon, May 21, 2018 at 04:35:04PM +0800, Jason Wang wrote:
> We should not go for the error path after successfully transmitting a
> XDP buffer after linearizing. Since the error path may try to pop and
> drop next packet and increase the drop counters. Fixing this by simply
> drop the refcnt of original page and go for xmit path.
>
> Fixes: 72979a6c3590 ("virtio_net: xdp, add slowpath case for non contiguous buffers")
> Cc: John Fastabend <john.fastabend@gmail.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> ---
> drivers/net/virtio_net.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index c15d240..6260d65 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -775,7 +775,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
> }
> *xdp_xmit = true;
> if (unlikely(xdp_page != page))
> - goto err_xdp;
> + put_page(page);
> rcu_read_unlock();
> goto xdp_xmit;
> case XDP_REDIRECT:
> --
> 2.7.4