NFP_MBOX_SYM_MIN_SIZE
max_data_sz = nfp_rtsym_size(pf->mbox) - NFP_MBOX_SYM_MIN_SIZE;
if (pf->mbox && nfp_rtsym_size(pf->mbox) < NFP_MBOX_SYM_MIN_SIZE) {
nfp_rtsym_size(pf->mbox), NFP_MBOX_SYM_MIN_SIZE);