linux-kernel - [PATCH net v2] net: renesas: rswitch: fix forwarding offload statemachine

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Message-Id: <20260205-fix-offloading-statemachine-v2-1-fafcf0c6eb1d@renesas.com>
Date: Thu, 05 Feb 2026 14:35:21 +0100
From: Michael Dege <michael.dege@...esas.com>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>, 
 Andrew Lunn <andrew+netdev@...n.ch>, 
 "David S. Miller" <davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, 
 Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>, 
 Nikita Yushchenko <nikita.yoush@...entembedded.com>
Cc: netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
 linux-kernel@...r.kernel.org, Michael Dege <michael.dege@...esas.com>
Subject: [PATCH net v2] net: renesas: rswitch: fix forwarding offload
 statemachine

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@...esas.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")

Changes in v2:
- Implemented suggested improvements to the function.
- Addded missing condition to an if statement.
- introduced bool variable, to reduce the the logic in the if
  statements.
- Link to v1: https://lore.kernel.org/r/20260205-fix-offloading-statemachine-v1-1-640224a531d0@renesas.com
---
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To: Andrew Lunn <andrew+netdev@...n.ch>
To: David S. Miller <davem@...emloft.net>
To: Eric Dumazet <edumazet@...gle.com>
To: Jakub Kicinski <kuba@...nel.org>
To: Paolo Abeni <pabeni@...hat.com>
To: Nikita Yushchenko <nikita.yoush@...entembedded.com>
To: Michael Dege <michael.dege@...esas.com>
Cc: netdev@...r.kernel.org
Cc: linux-renesas-soc@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
---
 drivers/net/ethernet/renesas/rswitch_l2.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/renesas/rswitch_l2.c b/drivers/net/ethernet/renesas/rswitch_l2.c
index 4a69ec77d69c..9433cd8adced 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>
@@ -60,6 +60,7 @@ static void rswitch_update_l2_hw_learning(struct rswitch_private *priv)
 static void rswitch_update_l2_hw_forwarding(struct rswitch_private *priv)
 {
 	struct rswitch_device *rdev;
+	bool new_forwarding_offload;
 	unsigned int fwd_mask;
 
 	/* calculate fwd_mask with zeroes in bits corresponding to ports that
@@ -73,8 +74,9 @@ static void rswitch_update_l2_hw_forwarding(struct rswitch_private *priv)
 	}
 
 	rswitch_for_all_ports(priv, rdev) {
-		if ((rdev_for_l2_offload(rdev) && rdev->forwarding_requested) ||
-		    rdev->forwarding_offloaded) {
+		new_forwarding_offload = (rdev_for_l2_offload(rdev) && rdev->forwarding_requested);
+
+		if (new_forwarding_offload || rdev->forwarding_offloaded) {
 			/* Update allowed offload destinations even for ports
 			 * with L2 offload enabled earlier.
 			 *
@@ -84,13 +86,10 @@ static void rswitch_update_l2_hw_forwarding(struct rswitch_private *priv)
 				  priv->addr + FWPC2(rdev->port));
 		}
 
-		if (rdev_for_l2_offload(rdev) &&
-		    rdev->forwarding_requested &&
-		    !rdev->forwarding_offloaded) {
+		if (new_forwarding_offload && !rdev->forwarding_offloaded)
 			rswitch_change_l2_hw_offloading(rdev, true, false);
-		} else if (rdev->forwarding_offloaded) {
+		else if (!new_forwarding_offload && rdev->forwarding_offloaded)
 			rswitch_change_l2_hw_offloading(rdev, false, false);
-		}
 	}
 }
 

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

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