Re: [PATCH net-next 7/8] net: switchdev: Replace port attr set SDO with a notification

[Ido Schimmel <idosch@mellanox.com>]

On Sun, Feb 24, 2019 at 08:47:27AM -0800, Florian Fainelli wrote:
> Le 2/23/19 à 2:32 AM, Ido Schimmel a écrit :
> > On Fri, Feb 22, 2019 at 03:59:25PM -0800, Florian Fainelli wrote:
> >> -	if (attr->flags & SWITCHDEV_F_NO_RECURSE)
> >> +	if (attr & SWITCHDEV_F_DEFER)
> >> +		rc = call_switchdev_blocking_notifiers(nt, dev,
> >> +						       &attr_info.info, NULL);
> >> +	else
> >> +		rc = call_switchdev_notifiers(nt, dev, &attr_info.info, NULL);
> > 
> > I don't believe this is needed. You're calling this function from
> > switchdev_port_attr_set_now() which is always called from process
> > context. switchdev_port_attr_set() takes care of that. Similar to
> > switchdev_port_obj_add().
> 
> Except for net/bridge/br_switchdev.c when we check the bridge port's
> flags support with PRE_BRIDGE_FLAGS. In that case we are executing from
> the caller (atomic) context and we can't defer otherwise that trumps the
> whole idea of being able to do a quick check and return that to the
> caller that we cannot support specific flags. How would you recommend
> approaching that?

In this case you can invoke call_switchdev_notifiers() directly from
br_switchdev_set_port_flag(). Eventually switchdev_port_attr_set() will
be gone and bridge code will invoke the notifiers directly.