Function devinit

freebsd/kern/subr_bus.c:426–456

static struct cdev *devctl_dev;

static void
devinit(void)
{
	int reserve;
	uma_zone_t z;

	devctl_dev = make_dev_credf(MAKEDEV_ETERNAL, &dev_cdevsw, 0, NULL,
	    UID_ROOT, GID_WHEEL, 0600, "devctl");
	mtx_init(&devsoftc.mtx, "dev mtx", "devd", MTX_DEF);
	cv_init(&devsoftc.cv, "dev cv");
	STAILQ_INIT(&devsoftc.devq);
	knlist_init_mtx(&devsoftc.sel.si_note, &devsoftc.mtx);
	if (devctl_queue_length > 0) {
		/*
		 * Allocate a zone for the messages. Preallocate 2% of these for
		 * a reserve. Allow only devctl_queue_length slabs to cap memory
		 * usage.  The reserve usually allows coverage of surges of
		 * events during memory shortages. Normally we won't have to
		 * re-use events from the queue, but will in extreme shortages.
		 */
		z = devsoftc.zone = uma_zcreate("DEVCTL",
		    sizeof(struct dev_event_info), NULL, NULL, NULL, NULL,
		    UMA_ALIGN_PTR, 0);
		reserve = max(devctl_queue_length / 50, 100);	/* 2% reserve */
		uma_zone_set_max(z, devctl_queue_length);
		uma_zone_set_maxcache(z, 0);
		uma_zone_reserve(z, reserve);
		uma_prealloc(z, reserve);
	}
	devctl2_init();
}

static int
devopen(struct cdev *dev, int oflags, int devtype, struct thread *td)