net/mlx4: Set proper build dependancy with vxlan

Make sure that vxlan_get_rx_port() is present in the kernel build in a manner
consistent with mlx4, else mlx4 can be made built-in where vxlan a module and
the phase of the build linking fails. Add CONFIG_MLX4_EN_VXLAN for that.

Also, #ifdef the advertizement and implementation of the mlx4 vxlan ndo
calls and related code under this config directive.
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlx4/Kconfig

@@ -23,6 +23,13 @@ config MLX4_EN_DCB
 
 	  If unsure, set to Y
 
+config MLX4_EN_VXLAN
+	bool "VXLAN offloads Support"
+	default y
+	depends on MLX4_EN && VXLAN && !(MLX4_EN=y && VXLAN=m)
+	---help---
+	  Say Y here if you want to use VXLAN offloads in the driver.
+
 config MLX4_CORE
 	tristate
 	depends on PCI

drivers/net/ethernet/mellanox/mlx4/en_netdev.c

@@ -1698,8 +1698,10 @@ int mlx4_en_start_port(struct net_device *dev)
 
 	mlx4_set_stats_bitmap(mdev->dev, &priv->stats_bitmap);
 
+#ifdef CONFIG_MLX4_EN_VXLAN
 	if (priv->mdev->dev->caps.flags2 & MLX4_DEV_CAP_FLAG2_VXLAN_OFFLOADS)
 		vxlan_get_rx_port(dev);
+#endif
 	priv->port_up = true;
 	netif_tx_start_all_queues(dev);
 	netif_device_attach(dev);
@@ -2267,6 +2269,7 @@ static int mlx4_en_get_phys_port_id(struct net_device *dev,
 	return 0;
 }
 
+#ifdef CONFIG_MLX4_EN_VXLAN
 static void mlx4_en_add_vxlan_offloads(struct work_struct *work)
 {
 	int ret;
@@ -2341,6 +2344,7 @@ static void mlx4_en_del_vxlan_port(struct  net_device *dev,
 
 	queue_work(priv->mdev->workqueue, &priv->vxlan_del_task);
 }
+#endif
 
 static const struct net_device_ops mlx4_netdev_ops = {
 	.ndo_open		= mlx4_en_open,
@@ -2368,8 +2372,10 @@ static const struct net_device_ops mlx4_netdev_ops = {
 	.ndo_busy_poll		= mlx4_en_low_latency_recv,
 #endif
 	.ndo_get_phys_port_id	= mlx4_en_get_phys_port_id,
+#ifdef CONFIG_MLX4_EN_VXLAN
 	.ndo_add_vxlan_port	= mlx4_en_add_vxlan_port,
 	.ndo_del_vxlan_port	= mlx4_en_del_vxlan_port,
+#endif
 };
 
 static const struct net_device_ops mlx4_netdev_ops_master = {
@@ -2461,8 +2467,10 @@ int mlx4_en_init_netdev(struct mlx4_en_dev *mdev, int port,
 	INIT_WORK(&priv->linkstate_task, mlx4_en_linkstate);
 	INIT_DELAYED_WORK(&priv->stats_task, mlx4_en_do_get_stats);
 	INIT_DELAYED_WORK(&priv->service_task, mlx4_en_service_task);
+#ifdef CONFIG_MLX4_EN_VXLAN
 	INIT_WORK(&priv->vxlan_add_task, mlx4_en_add_vxlan_offloads);
 	INIT_WORK(&priv->vxlan_del_task, mlx4_en_del_vxlan_offloads);
+#endif
 #ifdef CONFIG_MLX4_EN_DCB
 	if (!mlx4_is_slave(priv->mdev->dev)) {
 		if (mdev->dev->caps.flags & MLX4_DEV_CAP_FLAG_SET_ETH_SCHED) {

drivers/net/ethernet/mellanox/mlx4/mlx4_en.h

@@ -559,8 +559,10 @@ struct mlx4_en_priv {
 	struct work_struct linkstate_task;
 	struct delayed_work stats_task;
 	struct delayed_work service_task;
+#ifdef CONFIG_MLX4_EN_VXLAN
 	struct work_struct vxlan_add_task;
 	struct work_struct vxlan_del_task;
+#endif
 	struct mlx4_en_perf_stats pstats;
 	struct mlx4_en_pkt_stats pkstats;
 	struct mlx4_en_port_stats port_stats;