NSIGPOLL
static const __poll_t band_table[NSIGPOLL] = {
BUG_ON((reason < POLL_IN) || ((reason - POLL_IN) >= NSIGPOLL));
if (reason - POLL_IN >= NSIGPOLL)
[SIGPOLL] = { NSIGPOLL, SIL_POLL },
else if (si_code <= NSIGPOLL)
else if (si_code <= NSIGPOLL)