pn_ioctl
pfs_ioctl_t pn_ioctl;
KASSERT(pn->pn_ioctl != NULL, ("%s(): no callback", __func__));
return ((pn->pn_ioctl)(PFS_IOCTL_ARGNAMES));
if (pn->pn_ioctl == NULL) {
error = pn_ioctl(curthread, proc, pn, va->a_command, va->a_data);