Re: [PATCH net] net: renesas: rswitch: fix forwarding offload statemachine

[Nikita Yushchenko]

Hello Michael

> -		} else if (rdev->forwarding_offloaded) {
> +		} else if (rdev->forwarding_offloaded &&
> +			   !rdev->forwarding_requested) {
>   			rswitch_change_l2_hw_offloading(rdev, false, false);
>   		}

Although indeed the condition in the current code is not correct, I'm not sure comfortable with this fix.

Full condition for a port to be a valid candidate for hardware forwarding is

  rdev_for_l2_offload() && rdev->forwarding_requested

It is not obvious if at this point rdev_for_l2_offload() could get changed from the last call to 
rswitch_change_l2_hw_offloading(), so using only the partial condition at this point does not look good 
for me.

I'd suggest to either change to something like

if (rdev_for_l2_offload() && rdev->forwarding_requested && !rdev->forwarding_offloaded)
	rswitch_change_l2_hw_offloading(rdev, true, false);
if (!(rdev_for_l2_offload() && rdev->forwarding_requested) && rdev->forwarding_offloaded)
	rswitch_change_l2_hw_offloading(rdev, false, false);

Or maybe just

if (rdev_for_l2_offload() && rdev->forwarding_requested)
	rswitch_change_l2_hw_offloading(rdev, true, false);
else
	rswitch_change_l2_hw_offloading(rdev, false, false);

since rswitch_change_l2_hw_offloading() has internal check for the current state and returns early if 
the requested change is already applied.

Nikita