[PATCH net-next] net: dsa: realtek: rtl8366rb: Fix up port isolation

[Linus Walleij <linusw@kernel.org>]

Sashiko reports that we incorrectly disable isolation in the setup
loop while what we want to do is to enable it.

Just delete this setting: the next loop in the setup code, over the
user ports, isolate all the ports from each other, so only the CPU
port can see them.

Fix up the comments so it is clear what is going on, including a
missing word in the helper function.

Reported-by: Paolo Abeni <pabeni@redhat.com>
Closes: https://sashiko.dev/#/patchset/20260630-rtl8366rb-improvements-v2-0-05eb9d6a37f5%40kernel.org
Signed-off-by: Linus Walleij <linusw@kernel.org>
---
 drivers/net/dsa/realtek/rtl8366rb.c | 11 +++--------
 1 file changed, 3 insertions(+), 8 deletions(-)

diff --git a/drivers/net/dsa/realtek/rtl8366rb.c b/drivers/net/dsa/realtek/rtl8366rb.c
index d2fa8ff6a5d0..e615814049c1 100644
--- a/drivers/net/dsa/realtek/rtl8366rb.c
+++ b/drivers/net/dsa/realtek/rtl8366rb.c
@@ -794,8 +794,8 @@ static int rtl8366rb_setup_all_leds_off(struct realtek_priv *priv)
 static int rtl8366rb_port_set_isolation(struct realtek_priv *priv, int port,
 					u32 mask)
 {
-	/* Bit 0 enables isolation so set this if we enable isolation
-	 * any of the ports an clear it if we disable on all of them.
+	/* Bit 0 enables isolation so set this if we enable isolation on
+	 * any of the ports and clear it if we disable on all of them.
 	 */
 	if (mask)
 		mask = RTL8366RB_PORT_ISO_PORTS(mask) | RTL8366RB_PORT_ISO_EN;
@@ -950,11 +950,6 @@ static int rtl8366rb_setup(struct dsa_switch *ds)
 		 */
 		rtl8366rb_port_stp_state_set(ds, dp->index, BR_STATE_DISABLED);
 
-		/* Start with all ports completely isolated */
-		ret = rtl8366rb_port_set_isolation(priv, dp->index, 0);
-		if (ret)
-			return ret;
-
 		/* Disable learning */
 		ret = rtl8366rb_port_set_learning(priv, dp->index, false);
 		if (ret)
@@ -974,7 +969,7 @@ static int rtl8366rb_setup(struct dsa_switch *ds)
 		if (!dsa_port_is_user(dp))
 			continue;
 
-		/* Forward only to the CPU */
+		/* Forward only to the CPU, isolate from all other ports */
 		ret = rtl8366rb_port_set_isolation(priv, dp->index, upports_mask);
 		if (ret)
 			return ret;

---
base-commit: 23dad2d088dfc82cae1f5a936f8ff7ffebb38dd9
change-id: 20260702-rtl8366rb-fixes-a93f831ec2a4

Best regards,
--  
Linus Walleij <linusw@kernel.org>