Re: [PATCH net-next v2 07/10] net: dsa: lan9303: Added basic offloading of unicast traffic

[Egil Hjelmeland]

On 27. juli 2017 15:31, Andrew Lunn wrote:
> > > I think you are over-simplifying here. Say i have a layer 2 VPN and i
> > > bridge port 1 and the VPN? The software bridge still wants to do STP
> > > on port 1, in order to solve loops.
> >
> > Problem is that the mainline lan9303_separate_ports() does its
> > work by setting port 1 & 2 in STP BLOCKING state (and port 0 in
> > FORWARDING state). So my understanding is that it would break port
> > separation if LAN9303_SWE_PORT_STATE is written while the driver
> > is in the non-bridged state.
>
> If the hardware cannot do it, that is a different matter. But if the
> hardware can do STP states per port, you should try to make use of it
> here.

The HW does STP states per port, but not per pair of port.
I can set port 1 in learning, but I can not tell port 2
to ignore addresses learned on port 1. (Except by using VLAN).

Unless somebody can come up with an other way to implement the
port separation, I think this is how it has to be. I suppose
we don't want to break the port separation feature.


> > I thought the SW bridge would carry doing its STP work even if
> > there is a port_stp_state_set method on a DSA port?
>
> It will, but it means you are dropping frames in software, adding
> extra load to the CPU, reducing the available bandwidth for the other
> port, etc.

That is exactly the case with all traffic with the current mainline
driver.


>         Andrew

Egil