netdev - Re: [PATCH net-next v2 07/12] net: dsa: Add ability to program multicast filter for CPU port

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Date:   Wed, 30 Jan 2019 17:28:59 -0500
From:   Vivien Didelot <vivien.didelot@...il.com>
To:     Florian Fainelli <f.fainelli@...il.com>
Cc:     netdev@...r.kernel.org, Florian Fainelli <f.fainelli@...il.com>,
        andrew@...n.ch, davem@...emloft.net, idosch@...lanox.com,
        jiri@...lanox.com, ilias.apalodimas@...aro.org,
        ivan.khoronzhuk@...aro.org, roopa@...ulusnetworks.com,
        nikolay@...ulusnetworks.com
Subject: Re: [PATCH net-next v2 07/12] net: dsa: Add ability to program
 multicast filter for CPU port

Hi Florian,

On Tue, 29 Jan 2019 16:55:43 -0800, Florian Fainelli <f.fainelli@...il.com> wrote:

> +static int dsa_slave_sync_unsync_mdb_addr(struct net_device *dev,
> +					  const unsigned char *addr, bool add)
> +{
> +	struct switchdev_obj_port_mdb mdb = {
> +		.obj = {
> +			.id = SWITCHDEV_OBJ_ID_HOST_MDB,
> +			.flags = SWITCHDEV_F_DEFER,
> +		},
> +		.vid = 0,
> +	};
> +	int ret = -EOPNOTSUPP;

Assignment unneeded here.

> +
> +	ether_addr_copy(mdb.addr, addr);
> +	if (add)
> +		ret = switchdev_port_obj_add(dev, &mdb.obj, NULL);
> +	else
> +		ret = switchdev_port_obj_del(dev, &mdb.obj);
> +
> +	return ret;
> +}
> +
> +static int dsa_slave_sync_mdb_addr(struct net_device *dev,
> +				   const unsigned char *addr)
> +{
> +	return dsa_slave_sync_unsync_mdb_addr(dev, addr, true);
> +}
> +
> +static int dsa_slave_unsync_mdb_addr(struct net_device *dev,
> +				     const unsigned char *addr)
> +{
> +	return dsa_slave_sync_unsync_mdb_addr(dev, addr, false);
> +}

This wrapper isn't necessary IMO. I'd go with something like:

static int dsa_slave_sync(struct net_device *dev, const unsigned char *addr)
{
	struct switchdev_obj_port_mdb mdb = {
		.obj.id = SWITCHDEV_OBJ_ID_HOST_MDB,
		.obj.flags = SWITCHDEV_F_DEFER,
	};

	ether_addr_copy(mdb.addr, addr);

	return switchdev_port_obj_add(dev, &mdb.obj, NULL);
}

static int dsa_slave_unsync(struct net_device *dev, const unsigned char *addr)
{
	struct switchdev_obj_port_mdb mdb = {
		.obj.id = SWITCHDEV_OBJ_ID_HOST_MDB,
		.obj.flags = SWITCHDEV_F_DEFER,
	};

	ether_addr_copy(mdb.addr, addr);

	return switchdev_port_obj_del(dev, &mdb.obj);
}

We may eventually wrap this cryptic netdevery in:

static int dsa_slave_mc_sync(struct net_device *dev)
{
	return __hw_addr_sync_dev(&dev->mc, dev, dsa_slave_sync, dsa_slave_unsync);
}

static void dsa_slave_mc_unsync(struct net_device *dev)
{
	__hw_addr_unsync_dev(&dev->mc, dev, dsa_slave_sync);
}

> +
>  static int dsa_slave_open(struct net_device *dev)
>  {
>  	struct net_device *master = dsa_slave_to_master(dev);
> @@ -126,6 +159,8 @@ static int dsa_slave_close(struct net_device *dev)
>  
>  	dev_mc_unsync(master, dev);
>  	dev_uc_unsync(master, dev);
> +	__hw_addr_unsync_dev(&dev->mc, dev, dsa_slave_unsync_mdb_addr);
> +
>  	if (dev->flags & IFF_ALLMULTI)
>  		dev_set_allmulti(master, -1);
>  	if (dev->flags & IFF_PROMISC)
> @@ -150,7 +185,17 @@ static void dsa_slave_change_rx_flags(struct net_device *dev, int change)
>  static void dsa_slave_set_rx_mode(struct net_device *dev)
>  {
>  	struct net_device *master = dsa_slave_to_master(dev);
> +	struct dsa_port *dp = dsa_slave_to_port(dev);
>  
> +	/* If the port is bridged, the bridge takes care of sending
> +	 * SWITCHDEV_OBJ_ID_HOST_MDB to program the host's MC filter
> +	 */
> +	if (netdev_mc_empty(dev) || dp->bridge_dev)
> +		goto out;
> +
> +	__hw_addr_sync_dev(&dev->mc, dev, dsa_slave_sync_mdb_addr,
> +			   dsa_slave_unsync_mdb_addr);

And check the returned error code.

> +out:
>  	dev_mc_sync(master, dev);
>  	dev_uc_sync(master, dev);
>  }


Thanks,

	Vivien