Linux Virtualization - May 2018 - [PATCH net-next v12 1/5] net: Introduce generic failover module

On Thu, 24 May 2018 09:55:13 -0700
Sridhar Samudrala <sridhar.samudrala at intel.com> 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.

On 5/25/2018 3:38 PM, Stephen Hemminger wrote:
> On Thu, 24 May 2018 09:55:13 -0700
> Sridhar Samudrala <sridhar.samudrala at intel.com> 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.

On Fri, 25 May 2018 16:06:58 -0700
"Samudrala, Sridhar" <sridhar.samudrala at intel.com> wrote:
> On 5/25/2018 3:38 PM, Stephen Hemminger wrote:
> > On Thu, 24 May 2018 09:55:13 -0700
> > Sridhar Samudrala <sridhar.samudrala at intel.com> 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.
> 
They are already used by bonding and team.
I don't see why this can't reuse them.

On Fri, 25 May 2018 16:06:58 -0700
"Samudrala, Sridhar" <sridhar.samudrala at intel.com> wrote:
> On 5/25/2018 3:38 PM, Stephen Hemminger wrote:
> > On Thu, 24 May 2018 09:55:13 -0700
> > Sridhar Samudrala <sridhar.samudrala at intel.com> 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