A change of the port state of one port, caused the state of another
port to change. This behvior was unintended.

Signed-off-by: Michael Dege <michael.dege@renesas.com>
---
A change of the port state of one port, caused the state of another
port to change. This behvior was unintended.

Fixes: b7502b1043de86967ff341819d05e09a8dbe8b2b ("net: renesas: rswitch: add offloading for L2 switching")
---
 drivers/net/ethernet/renesas/rswitch_l2.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/renesas/rswitch_l2.c b/drivers/net/ethernet/renesas/rswitch_l2.c
index 4a69ec77d69c..dcf726793bdc 100644
--- a/drivers/net/ethernet/renesas/rswitch_l2.c
+++ b/drivers/net/ethernet/renesas/rswitch_l2.c
@@ -1,7 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 /* Renesas Ethernet Switch device driver
  *
- * Copyright (C) 2025 Renesas Electronics Corporation
+ * Copyright (C) 2025 - 2026 Renesas Electronics Corporation
  */
 
 #include <linux/err.h>
@@ -88,7 +88,8 @@ static void rswitch_update_l2_hw_forwarding(struct rswitch_private *priv)
 		    rdev->forwarding_requested &&
 		    !rdev->forwarding_offloaded) {
 			rswitch_change_l2_hw_offloading(rdev, true, false);
-		} else if (rdev->forwarding_offloaded) {
+		} else if (rdev->forwarding_offloaded &&
+			   !rdev->forwarding_requested) {
 			rswitch_change_l2_hw_offloading(rdev, false, false);
 		}
 	}

---
base-commit: f14faaf3a1fb3b9e4cf2e56269711fb85fba9458
change-id: 20260205-fix-offloading-statemachine-1d301630a08d

Best regards,
-- 
Michael Dege <michael.dege@renesas.com>

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

WBR,
Nikita Yushchenko,
System Software Engineer @ Cogent Embedded

05.02.2026 08:47, Nikita Yushchenko wrote:
> 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.

May be even better to add

   bool new_forwarding_offloaded = rdev_for_l2_offload(rdev) && rdev->forwarding_requested;

at the beginning of the loop body, and use this flag over the loop - it will make the code shorter and 
cleaner.

>    rdev_for_l2_offload() && rdev->forwarding_requested

rdev_for_l2_offload(rdev) && rdev->forwarding_requested