TF_REASSEMBLING
if (tp->t_flags & TF_REASSEMBLING) {
tp->t_flags |= TF_REASSEMBLING;
KASSERT((tp->t_flags & TF_REASSEMBLING) != 0);
tp->t_flags &= ~TF_REASSEMBLING;
if (((tp)->t_flags & TF_REASSEMBLING) == 0) { \