[PATCH net-next] net: ipv6: add IFLA_RA_MTU to expose mtu value in the RA message

[Rocco Yue]

On Thu, 2021-07-29 at 08:41 -0600, David Ahern wrote:
> On 7/29/21 3:02 AM, Rocco Yue wrote:
>> diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
>> index 4882e81514b6..ea6c872c5f2c 100644
>> --- a/include/uapi/linux/if_link.h
>> +++ b/include/uapi/linux/if_link.h
>> @@ -347,7 +347,7 @@ enum {
>>  	 */
>>  	IFLA_PARENT_DEV_NAME,
>>  	IFLA_PARENT_DEV_BUS_NAME,
>> -
>> +	IFLA_RA_MTU,
>>  	__IFLA_MAX
>>  };
>>  
>> diff --git a/include/uapi/linux/ipv6.h b/include/uapi/linux/ipv6.h
>> index 70603775fe91..3dbcf212b766 100644
>> --- a/include/uapi/linux/ipv6.h
>> +++ b/include/uapi/linux/ipv6.h
>> @@ -190,6 +190,7 @@ enum {
>>  	DEVCONF_NDISC_TCLASS,
>>  	DEVCONF_RPL_SEG_ENABLED,
>>  	DEVCONF_RA_DEFRTR_METRIC,
>> +	DEVCONF_RA_MTU,
>>  	DEVCONF_MAX
>>  };
>>  
> 
> you do not need both IFLA and DEVCONF. Drop the DEVCONF completely. IFLA
> attribute can be used for both inspection and notification on change.

Hi David,

Thanks for your review.

Because the purpose of this patch is for userspace to correctly read the
ra_mtu value of different network device, if the DEVCONF is completely dropped,
does that mean I can add the "ra_mtu" member in the "struct net_device" .

> Also do not add mailing lists that cause bounces. Specifically, you tend
> to add wsd_upstream at mediatek.com as a cc and every response to you
> generates a bounce message for this address.

Thanks for pointing out the problem, I will remove it from the mailing list.

Best Regards,
Rocco