mlx4_db_alloc
err = mlx4_db_alloc(dev->dev, &cq->db, 1);
err = mlx4_db_alloc(dev->dev, &qp->db, 0);
err = mlx4_db_alloc(dev->dev, &srq->db, 0);
EXPORT_SYMBOL_GPL(mlx4_db_alloc);
err = mlx4_db_alloc(dev, &wqres->db, 1);
int mlx4_db_alloc(struct mlx4_dev *dev, struct mlx4_db *db, unsigned int order);