Re: [PATCHv2 net-next] Bonding: add per-port priority for failover re-selection

[Hangbin Liu <liuhangbin@gmail.com>]

On Tue, Jun 14, 2022 at 08:52:58PM -0700, Stephen Hemminger wrote:
> On Wed, 15 Jun 2022 11:29:34 +0800
> Hangbin Liu <liuhangbin@gmail.com> wrote:
> 
> > diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
> > index 5a6f44455b95..41b3244747fa 100644
> > --- a/drivers/net/bonding/bond_netlink.c
> > +++ b/drivers/net/bonding/bond_netlink.c
> > @@ -27,6 +27,7 @@ static size_t bond_get_slave_size(const struct net_device *bond_dev,
> >  		nla_total_size(sizeof(u16)) +	/* IFLA_BOND_SLAVE_AD_AGGREGATOR_ID */
> >  		nla_total_size(sizeof(u8)) +	/* IFLA_BOND_SLAVE_AD_ACTOR_OPER_PORT_STATE */
> >  		nla_total_size(sizeof(u16)) +	/* IFLA_BOND_SLAVE_AD_PARTNER_OPER_PORT_STATE */
> > +		nla_total_size(sizeof(s32)) +	/* IFLA_BOND_SLAVE_PRIO */
> >  		0;
> >  }
> 
> Why the choice to make it signed? It would be clearer as unsigned value.

Let's say you have a bond with 10 slaves. You want to make 1 slave with
lowest priority. With singed value, you can just set it to -10 while other
slaves keep using the default value 0.

> Also, using full 32 bits seems like overkill.

Yes, it seems too much for just priority. This is to compatible with team
prio option[1].

[1] https://github.com/jpirko/libteam/blob/master/man/teamd.conf.5#L138

Thanks
Hangbin