add_byte
rc = add_byte(&pFill, 1 + ctrl->push_flag, &usedbytes, &available);
rc = add_byte(&pFill, 1, &usedbytes, &available);
rc = add_byte(&pFill, ctrl->bus, &usedbytes, &available);
rc = add_byte(&pFill, PCI_SLOT(ctrl->pci_dev->devfn), &usedbytes, &available);
rc = add_byte(&pFill, PCI_FUNC(ctrl->pci_dev->devfn), &usedbytes, &available);