pn_attr
pn->pn_attr = attr;
pn->pn_attr = attr;
pn->pn_attr = attr;
pfs_attr_t pn_attr;
KASSERT(pn->pn_attr != NULL, ("%s(): no callback", __func__));
return ((pn->pn_attr)(PFS_ATTR_ARGNAMES));
if (pn->pn_attr != NULL)
error = pn_attr(curthread, proc, pn, vap);