Subject: Re: [PATCH net-next v12 1/5] net: Introduce generic failover module

From: "Samudrala, Sridhar" <[email-masked]>
Date: Wed, 30 May 2018 19:58:30 -0700

On 5/30/2018 7:52 PM, Stephen Hemminger wrote:
> On Fri, 25 May 2018 16:06:58 -0700
> "Samudrala, Sridhar" <[email-masked]> wrote:
>
>> On 5/25/2018 3:38 PM, Stephen Hemminger wrote:
>>> On Thu, 24 May 2018 09:55:13 -0700
>>> Sridhar Samudrala <[email-masked]> wrote:
>>>   
>>>> diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
>>>> index 03ed492c4e14..0f4ba52b641d 100644
>>>> --- a/include/linux/netdevice.h
>>>> +++ b/include/linux/netdevice.h
>>>> @@ -1421,6 +1421,8 @@ struct net_device_ops {
>>>>     *	entity (i.e. the master device for bridged veth)
>>>>     * @IFF_MACSEC: device is a MACsec device
>>>>     * @IFF_NO_RX_HANDLER: device doesn't support the rx_handler hook
>>>> + * @IFF_FAILOVER: device is a failover master device
>>>> + * @IFF_FAILOVER_SLAVE: device is lower dev of a failover master device
>>>>     */
>>>>    enum netdev_priv_flags {
>>>>    	IFF_802_1Q_VLAN			= 1<<0,
>>>> @@ -1450,6 +1452,8 @@ enum netdev_priv_flags {
>>>>    	IFF_PHONY_HEADROOM		= 1<<24,
>>>>    	IFF_MACSEC			= 1<<25,
>>>>    	IFF_NO_RX_HANDLER		= 1<<26,
>>>> +	IFF_FAILOVER			= 1<<27,
>>>> +	IFF_FAILOVER_SLAVE		= 1<<28,
>>>>    };
>>> Why is FAILOVER any different than other master/slave relationships.
>>> I don't think you need to take up precious netdev flag bits for this.
>> These are netdev priv flags.
>> Jiri says that IFF_MASTER/IFF_SLAVE are bonding specific flags and cannot be used
>> with other failover mechanisms. Team also doesn't use this flags and it has its own
>> priv_flags.
>>
> This change breaks userspace.
> We already have worked with partners to ignore devices marked as IFF_SLAVE,
> and IFF_SLAVE is visible to user space API's.

I specifically made sure not to remove IFF_SLAVE in the netvsc patch.

> NAK