Interrupt Handler Example

/*
 * Ethernet interface interrupt.
 */
if_etintr(int unit)
{
 ETIO io;
 struct et_info *ei;
 register int s = splimp(); /* get the spin lock */

 ASSERT(unit == 0);
 ei = &et_info;
 io = ei->ei_io;

 if (io == 0) { /* ignore early interrupts */
     printf("et0: early interrupt\n");
     splx(s);
     return 1;
 }
 IFNET_LOCKNOSPL(&ei->ei_if);
 et_poll(ei);
 IFNET_UNLOCKNOSPL(&ei->ei_if);
 splx(s);
}