net/mlx4_en: Limit the number of RX rings

Limit the number of RX rings by the number of cores
in the system.
Signed-off-by: NInbar Karmy <inbark@mellanox.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

@@ -1742,12 +1742,17 @@ static int mlx4_en_set_rxnfc(struct net_device *dev, struct ethtool_rxnfc *cmd)
 	return err;
 }
 
+static int mlx4_en_get_max_num_rx_rings(struct net_device *dev)
+{
+	return min_t(int, num_online_cpus(), MAX_RX_RINGS);
+}
+
 static void mlx4_en_get_channels(struct net_device *dev,
 				 struct ethtool_channels *channel)
 {
 	struct mlx4_en_priv *priv = netdev_priv(dev);
 
-	channel->max_rx = MAX_RX_RINGS;
+	channel->max_rx = mlx4_en_get_max_num_rx_rings(dev);
 	channel->max_tx = priv->mdev->profile.max_num_tx_rings_p_up;
 
 	channel->rx_count = priv->rx_ring_num;