net/mlx4_en: Check the enabling mtu flag in SET_PORT wrapper flow

Make sure MTU mask flag is set using new field upon set port
request. In addition, move this code into a helper function for better
code readability.
Signed-off-by: Shaker Daibes <shakerd@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -52,6 +52,7 @@
 
 #define MLX4_FLAG2_V_IGNORE_FCS_MASK		BIT(1)
 #define MLX4_FLAG2_V_USER_MTU_MASK		BIT(5)
+#define MLX4_FLAG_V_MTU_MASK			BIT(0)
 #define MLX4_IGNORE_FCS_MASK			0x1
 #define MLX4_TC_MAX_NUMBER			8
 
@@ -1240,6 +1241,38 @@ void mlx4_reset_roce_gids(struct mlx4_dev *dev, int slave)
 	return;
 }
 
+static void
+mlx4_en_set_port_mtu(struct mlx4_dev *dev, int slave, int port,
+		     struct mlx4_set_port_general_context *gen_context)
+{
+	struct mlx4_priv *priv = mlx4_priv(dev);
+	struct mlx4_mfunc_master_ctx *master = &priv->mfunc.master;
+	struct mlx4_slave_state *slave_st = &master->slave_state[slave];
+	u16 mtu, prev_mtu;
+
+	/* Mtu is configured as the max USER_MTU among all
+	 * the functions on the port.
+	 */
+	mtu = be16_to_cpu(gen_context->mtu);
+	mtu = min_t(int, mtu, dev->caps.eth_mtu_cap[port] +
+		    ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
+	prev_mtu = slave_st->mtu[port];
+	slave_st->mtu[port] = mtu;
+	if (mtu > master->max_mtu[port])
+		master->max_mtu[port] = mtu;
+	if (mtu < prev_mtu && prev_mtu == master->max_mtu[port]) {
+		int i;
+
+		slave_st->mtu[port] = mtu;
+		master->max_mtu[port] = mtu;
+		for (i = 0; i < dev->num_slaves; i++)
+			master->max_mtu[port] =
+				max_t(u16, master->max_mtu[port],
+				      master->slave_state[i].mtu[port]);
+	}
+	gen_context->mtu = cpu_to_be16(master->max_mtu[port]);
+}
+
 static void
 mlx4_en_set_port_user_mtu(struct mlx4_dev *dev, int slave, int port,
 			  struct mlx4_set_port_general_context *gen_context)
@@ -1278,7 +1311,6 @@ static int mlx4_common_set_port(struct mlx4_dev *dev, int slave, u32 in_mod,
 	struct mlx4_priv *priv = mlx4_priv(dev);
 	struct mlx4_port_info *port_info;
 	struct mlx4_mfunc_master_ctx *master = &priv->mfunc.master;
-	struct mlx4_slave_state *slave_st = &master->slave_state[slave];
 	struct mlx4_set_port_rqp_calc_context *qpn_context;
 	struct mlx4_set_port_general_context *gen_context;
 	struct mlx4_roce_gid_entry *gid_entry_tbl, *gid_entry_mbox, *gid_entry_mb1;
@@ -1289,7 +1321,6 @@ static int mlx4_common_set_port(struct mlx4_dev *dev, int slave, u32 in_mod,
 	int base;
 	u32 in_modifier;
 	u32 promisc;
-	u16 mtu, prev_mtu;
 	int err;
 	int i, j;
 	int offset;
@@ -1332,26 +1363,10 @@ static int mlx4_common_set_port(struct mlx4_dev *dev, int slave, u32 in_mod,
 			break;
 		case MLX4_SET_PORT_GENERAL:
 			gen_context = inbox->buf;
-			/* Mtu is configured as the max MTU among all the
-			 * the functions on the port. */
-			mtu = be16_to_cpu(gen_context->mtu);
-			mtu = min_t(int, mtu, dev->caps.eth_mtu_cap[port] +
-				    ETH_HLEN + VLAN_HLEN + ETH_FCS_LEN);
-			prev_mtu = slave_st->mtu[port];
-			slave_st->mtu[port] = mtu;
-			if (mtu > master->max_mtu[port])
-				master->max_mtu[port] = mtu;
-			if (mtu < prev_mtu && prev_mtu ==
-						master->max_mtu[port]) {
-				slave_st->mtu[port] = mtu;
-				master->max_mtu[port] = mtu;
-				for (i = 0; i < dev->num_slaves; i++) {
-					master->max_mtu[port] =
-					max(master->max_mtu[port],
-					    master->slave_state[i].mtu[port]);
-				}
-			}
-			gen_context->mtu = cpu_to_be16(master->max_mtu[port]);
+
+			if (gen_context->flags & MLX4_FLAG_V_MTU_MASK)
+				mlx4_en_set_port_mtu(dev, slave, port,
+						     gen_context);
 
 			if (gen_context->flags2 & MLX4_FLAG2_V_USER_MTU_MASK)
 				mlx4_en_set_port_user_mtu(dev, slave, port,