Subject: Re: [PATCH v3 net-next 12/24] net: dsa: Copy the vlan_filtering setting on the CPU port if it's global

From: Andrew Lunn <[email-masked]>
Date: Sat, 13 Apr 2019 17:23:07 +0200

On Sat, Apr 13, 2019 at 04:28:10AM +0300, Vladimir Oltean wrote:
> The current behavior is not as obvious as one would assume (which is
> that, if the driver set vlan_filtering_is_global = 1, then checking any
> dp->vlan_filtering would yield the same result). Only the ports which
> are actively enslaved into a bridge would have vlan_filtering set.
> 
> This makes it tricky for drivers to check what the global state is.
> Moreover, the most obvious place to check for this setting, the CPU
> port, is not populated since it's not being enslaved to the bridge.
> So fix this and make the CPU port hold the global state of VLAN
> filtering on this switch.
> 
> Signed-off-by: Vladimir Oltean <[email-masked]>
> ---
> Changes in v3:
> Patch is new.
> 
>  net/dsa/port.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/net/dsa/port.c b/net/dsa/port.c
> index c8eb2cbcea6e..acb4ed1f9929 100644
> --- a/net/dsa/port.c
> +++ b/net/dsa/port.c
> @@ -190,6 +190,8 @@ static bool dsa_port_can_apply_vlan_filtering(struct dsa_port *dp,
>  int dsa_port_vlan_filtering(struct dsa_port *dp, bool vlan_filtering,
>  			    struct switchdev_trans *trans)
>  {
> +	/* Violate a const pointer here */
> +	struct dsa_port *cpu_dp = (struct dsa_port *)dp->cpu_dp;

Hi Vladimir

As compilers get more picky, i expect that is going to result in a
warning. 

Since this is a switch global attribute, putting it in dsa_switch
would be better, next to vlan_filteris_is_global.

	Andrew