Re: [RFC net-next v3 06/10] net: bridge: mrp: switchdev: Extend switchdev API to offload MRP

[Horatiu Vultur]

The 01/25/2020 17:35, Andrew Lunn wrote:
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> 
> > SWITCHDEV_OBJ_ID_RING_TEST_MRP: This is used when to start/stop sending
> >   MRP_Test frames on the mrp ring ports. This is called only on nodes that have
> >   the role Media Redundancy Manager.
> 
> How do you handle the 'headless chicken' scenario? User space tells
> the port to start sending MRP_Test frames. It then dies. The hardware
> continues sending these messages, and the neighbours thinks everything
> is O.K, but in reality the state machine is dead, and when the ring
> breaks, the daemon is not there to fix it?
> 
> And it is not just the daemon that could die. The kernel could opps or
> deadlock, etc.
> 
> For a robust design, it seems like SWITCHDEV_OBJ_ID_RING_TEST_MRP
> should mean: start sending MRP_Test frames for the next X seconds, and
> then stop. And the request is repeated every X-1 seconds.

I totally missed this case, I will update this as you suggest.

> 
>      Andrew

-- 
/Horatiu