Re: [PATCH net-next v2 2/4] net: hsr: Add VLAN CTAG filter support

[Paolo Abeni <pabeni@redhat.com>]

On 10/24/24 12:30, MD Danish Anwar wrote:
> From: Murali Karicheri <m-karicheri2@ti.com>
> 
> This patch adds support for VLAN ctag based filtering at slave devices.
> The slave ethernet device may be capable of filtering ethernet packets
> based on VLAN ID. This requires that when the VLAN interface is created
> over an HSR/PRP interface, it passes the VID information to the
> associated slave ethernet devices so that it updates the hardware
> filters to filter ethernet frames based on VID. This patch adds the
> required functions to propagate the vid information to the slave
> devices.
> 
> Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
> Signed-off-by: MD Danish Anwar <danishanwar@ti.com>
> ---
>  net/hsr/hsr_device.c | 71 +++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 70 insertions(+), 1 deletion(-)
> 
> diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
> index 0ca47ebb01d3..ff586bdc2bde 100644
> --- a/net/hsr/hsr_device.c
> +++ b/net/hsr/hsr_device.c
> @@ -515,6 +515,68 @@ static void hsr_change_rx_flags(struct net_device *dev, int change)
>  	}
>  }
>  
> +static int hsr_ndo_vlan_rx_add_vid(struct net_device *dev,
> +				   __be16 proto, u16 vid)
> +{
> +	struct hsr_port *port;
> +	struct hsr_priv *hsr;
> +	int ret = 0;
> +
> +	hsr = netdev_priv(dev);
> +
> +	hsr_for_each_port(hsr, port) {
> +		if (port->type == HSR_PT_MASTER)
> +			continue;

If the desired behavior is to ignore INTERLINK port, I think you should
explicitly skip them here, otherwise you will end-up in a
nondeterministic state.

> +		ret = vlan_vid_add(port->dev, proto, vid);
> +		switch (port->type) {
> +		case HSR_PT_SLAVE_A:
> +			if (ret) {
> +				netdev_err(dev, "add vid failed for Slave-A\n");
> +				return ret;
> +			}
> +			break;
> +
> +		case HSR_PT_SLAVE_B:
> +			if (ret) {
> +				/* clean up Slave-A */
> +				netdev_err(dev, "add vid failed for Slave-B\n");
> +				vlan_vid_del(port->dev, proto, vid);

This code relies on a specific port_list order - which is actually
respected at list creation time. Still such assumption looks fragile and
may lead to long term bugs.

I think would be better to refactor the above loop handling arbitrary
HSR_PT_SLAVE_A, HSR_PT_SLAVE_B order. Guestimate is that the complexity
will not increase measurably.

> +				return ret;
> +			}
> +			break;
> +		default:
> +			break;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +static int hsr_ndo_vlan_rx_kill_vid(struct net_device *dev,
> +				    __be16 proto, u16 vid)
> +{
> +	struct hsr_port *port;
> +	struct hsr_priv *hsr;
> +
> +	hsr = netdev_priv(dev);
> +
> +	hsr_for_each_port(hsr, port) {
> +		if (port->type == HSR_PT_MASTER)
> +			continue;

I think it would be more consistent just removing the above statement...

> +		switch (port->type) {
> +		case HSR_PT_SLAVE_A:
> +		case HSR_PT_SLAVE_B:
> +			vlan_vid_del(port->dev, proto, vid);
> +			break;
> +		default:> +			break;

... MASTER and INTERLINK port will be ignored anyway.

> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static const struct net_device_ops hsr_device_ops = {
>  	.ndo_change_mtu = hsr_dev_change_mtu,
>  	.ndo_open = hsr_dev_open,

Cheers,

Paolo