SIS_RESTART
sih->sih_state &= ~SIS_RESTART;
KASSERT((sih->sih_state & (SIS_PENDING | SIS_RESTART)) == 0);
KASSERT((sih->sih_state & SIS_RESTART) == 0);
sih->sih_state |= SIS_RESTART;
KASSERT((sih->sih_state & (SIS_PENDING | SIS_RESTART)) ==
if (sih->sih_state & SIS_RESTART) {
sih->sih_state &= ~SIS_RESTART;