Re: [PATCH net v2] usbnet: cap max_mtu for drivers without bind callback

Laurent Vivier <[email protected]> Thu, 30 Jul 2026 09:30:57 +0200

Newsgroups	org.kernel.vger.linux-usb,org.kernel.vger.linux-kernel,org.kernel.vger.netdev,org.kernel.vger.stable
Message-ID	<[email protected]>

On 7/30/26 02:52, Jakub Kicinski wrote:
> On Mon, 27 Jul 2026 09:23:04 +0200 Laurent Vivier wrote:
>> -		if ((dev->driver_info->flags & FLAG_NOMAXMTU) == 0 &&
>> -		    net->max_mtu > (dev->hard_mtu - net->hard_header_len))
>> +		if (dev->driver_info->flags & FLAG_NOMAXMTU)
>> +			net->max_mtu = ETH_MAX_MTU;
>> +		else
>>   			net->max_mtu = dev->hard_mtu - net->hard_header_len;
> 
> Sashikos point out that this will causes issues for existing drivers in
> both directions. Some drivers explicitly set max_mtu. So we need to move
> the
> 
> 	net->max_mtu = ETH_MAX_MTU;
> 
> line before the call to ->bind ?

So you mean like my v1?

Thanks,
Laurent