# Re: \[PATCH net-next\] net: virtio: use eth\_hw\_addr\_set()

- From: Michael S. Tsirkin \<mst@redhat.com\>
- Date: 2021-10-27 07:23:27 
- List: virtualization
- Page: https://ratatoskr.run/virtualization/2021/10/11214750
- Thread: https://ratatoskr.run/netdev/2021/10/11214694/t.md

```text
On Tue, Oct 26, 2021 at 10:56:34AM -0700, Jakub Kicinski wrote:
> Commit 406f42fa0d3c ("net-next: When a bond have a massive amount
> of VLANs...") introduced a rbtree for faster Ethernet address look
> up. To maintain netdev->dev_addr in this tree we need to make all
> the writes to it go through appropriate helpers.
> 
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

> ---
> CC: mst@redhat.com
> CC: <redacted>
> CC: <redacted>
> ---
>  drivers/net/virtio_net.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index c501b5974aee..b7f35aff8e82 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -3177,12 +3177,16 @@ static int virtnet_probe(struct virtio_device *vdev)
>  	dev->max_mtu = MAX_MTU;
>  
>  	/* Configuration may specify what MAC to use.  Otherwise random. */
> -	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC))
> +	if (virtio_has_feature(vdev, VIRTIO_NET_F_MAC)) {
> +		u8 addr[MAX_ADDR_LEN];
> +
>  		virtio_cread_bytes(vdev,
>  				   offsetof(struct virtio_net_config, mac),
> -				   dev->dev_addr, dev->addr_len);
> -	else
> +				   addr, dev->addr_len);

Maybe BUG_ON(dev->addr_len > sizeof addr);

here just to make sure we don't overflow addr silently?


> +		dev_addr_set(dev, addr);
> +	} else {
>  		eth_hw_addr_random(dev);
> +	}
>  
>  	/* Set up our device-specific information */
>  	vi = netdev_priv(dev);
> -- 
> 2.31.1

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```