SCSI_UNKNOWN
if (sdev->scsi_level <= SCSI_2 && sdev->scsi_level != SCSI_UNKNOWN)
starget->scsi_level != SCSI_UNKNOWN)
sdev->scsi_level != SCSI_UNKNOWN &&
sdev->scsi_level != SCSI_UNKNOWN &&
sdev->scsi_level == SCSI_UNKNOWN)