[PATCH 5.8 17/56] net: dsa: rtl8366: Properly clear member config

[Greg Kroah-Hartman]

From: Linus Walleij <linus.walleij@xxxxxxxxxx>

[ Upstream commit 4ddcaf1ebb5e4e99240f29d531ee69d4244fe416 ]

When removing a port from a VLAN we are just erasing the
member config for the VLAN, which is wrong: other ports
can be using it.

Just mask off the port and only zero out the rest of the
member config once ports using of the VLAN are removed
from it.

Reported-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
Fixes: d8652956cf37 ("net: dsa: realtek-smi: Add Realtek SMI driver")
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/net/dsa/rtl8366.c |   20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

--- a/drivers/net/dsa/rtl8366.c
+++ b/drivers/net/dsa/rtl8366.c
@@ -452,13 +452,19 @@ int rtl8366_vlan_del(struct dsa_switch *
 				return ret;
 
 			if (vid == vlanmc.vid) {
-				/* clear VLAN member configurations */
-				vlanmc.vid = 0;
-				vlanmc.priority = 0;
-				vlanmc.member = 0;
-				vlanmc.untag = 0;
-				vlanmc.fid = 0;
-
+				/* Remove this port from the VLAN */
+				vlanmc.member &= ~BIT(port);
+				vlanmc.untag &= ~BIT(port);
+				/*
+				 * If no ports are members of this VLAN
+				 * anymore then clear the whole member
+				 * config so it can be reused.
+				 */
+				if (!vlanmc.member && vlanmc.untag) {
+					vlanmc.vid = 0;
+					vlanmc.priority = 0;
+					vlanmc.fid = 0;
+				}
 				ret = smi->ops->set_vlan_mc(smi, i, &vlanmc);
 				if (ret) {
 					dev_err(smi->dev,