net: qualcomm: rmnet: Allow to configure flags for existing devices

Add an option to configure the mux id, aggregation and commad feature
for existing rmnet devices. Implement the changelink netlink
operation for this.
Signed-off-by: NSubash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/qualcomm/rmnet/rmnet_config.c

@@ -320,6 +320,45 @@ static int rmnet_rtnl_validate(struct nlattr *tb[], struct nlattr *data[],
 	return 0;
 }
 
+static int rmnet_changelink(struct net_device *dev, struct nlattr *tb[],
+			    struct nlattr *data[],
+			    struct netlink_ext_ack *extack)
+{
+	struct rmnet_priv *priv = netdev_priv(dev);
+	struct net_device *real_dev;
+	struct rmnet_endpoint *ep;
+	struct rmnet_port *port;
+	u16 mux_id;
+
+	real_dev = __dev_get_by_index(dev_net(dev),
+				      nla_get_u32(tb[IFLA_LINK]));
+
+	if (!real_dev || !dev || !rmnet_is_real_dev_registered(real_dev))
+		return -ENODEV;
+
+	port = rmnet_get_port_rtnl(real_dev);
+
+	if (data[IFLA_VLAN_ID]) {
+		mux_id = nla_get_u16(data[IFLA_VLAN_ID]);
+		ep = rmnet_get_endpoint(port, priv->mux_id);
+
+		hlist_del_init_rcu(&ep->hlnode);
+		hlist_add_head_rcu(&ep->hlnode, &port->muxed_ep[mux_id]);
+
+		ep->mux_id = mux_id;
+		priv->mux_id = mux_id;
+	}
+
+	if (data[IFLA_VLAN_FLAGS]) {
+		struct ifla_vlan_flags *flags;
+
+		flags = nla_data(data[IFLA_VLAN_FLAGS]);
+		port->ingress_data_format = flags->flags & flags->mask;
+	}
+
+	return 0;
+}
+
 static size_t rmnet_get_size(const struct net_device *dev)
 {
 	return nla_total_size(2) /* IFLA_VLAN_ID */ +
@@ -335,6 +374,7 @@ struct rtnl_link_ops rmnet_link_ops __read_mostly = {
 	.newlink	= rmnet_newlink,
 	.dellink	= rmnet_dellink,
 	.get_size	= rmnet_get_size,
+	.changelink     = rmnet_changelink,
 };
 
 /* Needs either rcu_read_lock() or rtnl lock */