On Wed Mar 24 2021, Vladimir Oltean wrote:
> From: Vladimir Oltean <vladimir.oltean@nxp.com>
>
> DSA is aware of switches with global VLAN filtering since the blamed
> commit, but it makes a bad decision when multiple bridges are spanning
> the same switch:
>
> ip link add br0 type bridge vlan_filtering 1
> ip link add br1 type bridge vlan_filtering 1
> ip link set swp2 master br0
> ip link set swp3 master br0
> ip link set swp4 master br1
> ip link set swp5 master br1
> ip link set swp5 nomaster
> ip link set swp4 nomaster
> [138665.939930] sja1105 spi0.1: port 3: dsa_core: VLAN filtering is a global setting
> [138665.947514] DSA: failed to notify DSA_NOTIFIER_BRIDGE_LEAVE
>
> When all ports leave br1, DSA blindly attempts to disable VLAN filtering
> on the switch, ignoring the fact that br0 still exists and is VLAN-aware
> too. It fails while doing that.
>
> This patch checks whether any port exists at all and is under a
> VLAN-aware bridge.
>
> Fixes: d371b7c92d19 ("net: dsa: Unset vlan_filtering when ports leave the bridge")
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
> Tested-by: Florian Fainelli <f.fainelli@gmail.com>
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>

Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de>