@staticmethod
def disk_param(name, size, snapshot_profile, cmdline=None, kernel=None):
    """ Return disk parameter structure. """
    disk_params = {}
    if cmdline:
        disk_params['cmdline'] = cmdline
    if kernel:
        disk_params['kernel'] = kernel
    if name:
        disk_params['name'] = name
    if snapshot_profile is not None:
        disk_params['snapshot_profile'] = snapshot_profile
    if size:
        disk_params['size'] = size
    return disk_params
