Re: [PATCH v3 net-next 03/11] net: switchdev: remove the transaction structure from port object notifiers

[Vladimir Oltean <olteanv@gmail.com>]

On Thu, Jan 07, 2021 at 12:38:35PM +0200, Ido Schimmel wrote:
> +Petr
> 
> On Thu, Jan 07, 2021 at 01:17:20AM +0200, Vladimir Oltean wrote:
> >  static int mlxsw_sp_port_obj_add(struct net_device *dev,
> >  				 const struct switchdev_obj *obj,
> > -				 struct switchdev_trans *trans,
> >  				 struct netlink_ext_ack *extack)
> >  {
> >  	struct mlxsw_sp_port *mlxsw_sp_port = netdev_priv(dev);
> >  	const struct switchdev_obj_port_vlan *vlan;
> > +	struct switchdev_trans trans;
> >  	int err = 0;
> >  
> >  	switch (obj->id) {
> >  	case SWITCHDEV_OBJ_ID_PORT_VLAN:
> >  		vlan = SWITCHDEV_OBJ_PORT_VLAN(obj);
> > -		err = mlxsw_sp_port_vlans_add(mlxsw_sp_port, vlan, trans,
> > +
> 
> Got the regression results. The call to mlxsw_sp_span_respin() should be
> placed here because it needs to be triggered regardless of the return
> value of mlxsw_sp_port_vlans_add().

So before, mlxsw_sp_span_respin() was called right in between the
prepare phase and the commit phase, regardless of the error value of
mlxsw_sp_port_vlans_add. How does that work, I assume that
mlxsw_sp_span_respin_work gets to run after the commit phase because it
serializes using rtnl_lock()? Then why did it matter enough to schedule
it between the prepare and commit phase in the first place?
And what is there to do in mlxsw_sp_span_respin_work when
mlxsw_sp_port_vlans_add returns -EOPNOTSUPP, -EBUSY, -EINVAL, -EEXIST or
-ENOMEM?