set_lock_byte64
if (set_lock_byte64(lockp, udp->pid) == 0) {
set_lock_byte64(lockp, udp->pid) == 0) {
if (set_lock_byte64(lockp, udp->pid) == 0) {
if (set_lock_byte64(&mp->mutex_lockword64, udp->pid) == 0) {