Re: [PATCH net] net: do not bond/team netdevices which use ml_priv

[Hangbin Liu <hangbin.liu@linux.dev>]

On Wed, Aug 19, 2026 at 08:15:42PM +0200, Oliver Hartkopp wrote:
> Hi Hangbin, all,
> 
> thanks for your feedback!
> 
> In fact checking for dev->ml_priv != NULL seems to be too hard and would
> likely create some breaking setups.
> 
> I have sent a patch on the Linux-CAN ML that makes the CAN subsystem robust
> against alien ARPHRD_CAN interfaces that might be created by TUN/TAP via
> TUNSETLINK ioctl:
> 
> https://lore.kernel.org/linux-can/20260819160822.8256-1-socketcan@hartkopp.net/
> 
> The other question remains how to make bonding/team keep the fingers away
> from incompatible net devices.
> 
> The current black listing approach from Jiale Yao (using a unified helper as
> suggested by Jiri Pirko) seems to be the best way to go now:
> 
> https://lore.kernel.org/netdev/20260728151240.89434-1-yaojiale02@163.com/
> 
> +		if (port_dev->type == ARPHRD_CAN ||
> +		    port_dev->type == ARPHRD_IEEE802154 ||
> +		    port_dev->type == ARPHRD_IEEE802154_MONITOR) {
> +			NL_SET_ERR_MSG(extack,
> +				       "CAN and IEEE 802.15.4 devices can't be added as a team port");
> +			netdev_err(dev, "Device %s is CAN or IEEE 802.15.4. These device types
> can't be added as a team port\n",
> +				   portname);
> +			return -EINVAL;
> +		}
> +	}
> +

This looks good to me to avoid making the checking to wide.

> 
> There might be other dev->types (e.g. ARPHRD_ARCNET) or a future white list
> approach this unified helper could support. For either team and bonding!
> 
> @Jiale Yao: What would be a good name for such helper in
> include/linux/if_arp.h ?
> 
> dev_is_not_ether_compatible(const struct net_device *dev)
> dev_is_ether_compatible(const struct net_device *dev)
> dev_has_special_l2_proto(const struct net_device *dev)
> dev_has_l2_proto(const struct net_device *dev)
> dev_is_pure_packet_bus(const struct net_device *dev)
> 
> or something like this?

I'm not good at naming. Leave it to you.

Thanks for your works!

Hangbin