KN_PROCESSING
KASSERT(kn == NULL || (kn->kn_status & KN_PROCESSING) != 0);
kn->kn_status = KN_PROCESSING;
scan->kqs_start.kn_status = KN_PROCESSING;
scan->kqs_end.kn_status = KN_PROCESSING;
KASSERT(scan->kqs_start.kn_status == KN_PROCESSING);
KASSERT(scan->kqs_end.kn_status == KN_PROCESSING);
if (kn->kn_status & KN_PROCESSING) {
kn->kn_status |= KN_PROCESSING;
KASSERT(kn->kn_status & KN_PROCESSING);
kn->kn_status &= ~KN_PROCESSING;
KASSERT(kn->kn_status & KN_PROCESSING);
KASSERT(kn->kn_status & KN_PROCESSING);