net/mlx5e: Vxlan, check maximum number of UDP ports

The NIC has a limited number of offloaded VXLAN UDP ports (usually 4).
Instead of letting the firmware fail when trying to add more ports than
it can handle, let the driver check it on its own.
Signed-off-by: Gal Pressman <galp@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -657,6 +657,7 @@ enum {
 struct mlx5e_vxlan_db {
 	spinlock_t			lock; /* protect vxlan table */
 	struct radix_tree_root		tree;
+	int				num_ports;
 };
 
 struct mlx5e_l2_rule {

drivers/net/ethernet/mellanox/mlx5/core/vxlan.c

@@ -52,6 +52,11 @@ void mlx5e_vxlan_init(struct mlx5e_priv *priv)
 		mlx5e_vxlan_add_port(priv, 4789);
 }
 
+static inline u8 mlx5e_vxlan_max_udp_ports(struct mlx5_core_dev *mdev)
+{
+	return MLX5_CAP_ETH(mdev, max_vxlan_udp_ports) ?: 4;
+}
+
 static int mlx5e_vxlan_core_add_port_cmd(struct mlx5_core_dev *mdev, u16 port)
 {
 	u32 in[MLX5_ST_SZ_DW(add_vxlan_udp_dport_in)]   = {0};
@@ -98,6 +103,13 @@ static void mlx5e_vxlan_add_port(struct mlx5e_priv *priv, u16 port)
 		return;
 	}
 
+	if (vxlan_db->num_ports >= mlx5e_vxlan_max_udp_ports(priv->mdev)) {
+		netdev_info(priv->netdev,
+			    "UDP port (%d) not offloaded, max number of UDP ports (%d) are already offloaded\n",
+			    port, mlx5e_vxlan_max_udp_ports(priv->mdev));
+		return;
+	}
+
 	if (mlx5e_vxlan_core_add_port_cmd(priv->mdev, port))
 		return;
 
@@ -114,6 +126,7 @@ static void mlx5e_vxlan_add_port(struct mlx5e_priv *priv, u16 port)
 	if (err)
 		goto err_free;
 
+	vxlan_db->num_ports++;
 	return;
 
 err_free:
@@ -163,6 +176,7 @@ static void mlx5e_vxlan_del_work(struct work_struct *work)
 	if (remove) {
 		mlx5e_vxlan_core_del_port_cmd(priv->mdev, port);
 		kfree(vxlan);
+		vxlan_db->num_ports--;
 	}
 	mutex_unlock(&priv->state_lock);
 	kfree(vxlan_work);

include/linux/mlx5/mlx5_ifc.h

@@ -668,7 +668,9 @@ struct mlx5_ifc_per_protocol_networking_offload_caps_bits {
 	u8         swp[0x1];
 	u8         swp_csum[0x1];
 	u8         swp_lso[0x1];
-	u8         reserved_at_23[0x1b];
+	u8         reserved_at_23[0xd];
+	u8         max_vxlan_udp_ports[0x8];
+	u8         reserved_at_38[0x6];
 	u8         max_geneve_opt_len[0x1];
 	u8         tunnel_stateless_geneve_rx[0x1];