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

- From: Stephen Hemminger \<stephen@networkplumber.org\>
- Date: 2018-05-31 02:53:03 
- List: netdev
- Page: https://ratatoskr.run/netdev/2018/05/11097961
- Thread: https://ratatoskr.run/netdev/2018/05/11097172/t.md

```text
On Fri, 25 May 2018 16:06:58 -0700
"Samudrala, Sridhar" [ref] wrote:

> On 5/25/2018 3:38 PM, Stephen Hemminger wrote:
> > On Thu, 24 May 2018 09:55:13 -0700
> > Sridhar Samudrala [ref] 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.

NAK
```