Remove the 'ivars' arguement to device_add_child() and

device_add_child_ordered().  'ivars' may now be set using the
device_set_ivars() function.

This makes it easier for us to change how arbitrary data structures are
associated with a device_t.  Eventually we won't be modifying device_t
to add additional pointers for ivars, softc data etc.

Despite my best efforts I've probably forgotten something so let me know
if this breaks anything.  I've been running with this change for months
and its been quite involved actually isolating all the changes from
the rest of the local changes in my tree.

Reviewed by:	peter, dfr

71 files changed, 189 insertions, 118 deletions

diff --git a/sys/alpha/alpha/autoconf.c b/sys/alpha/alpha/autoconf.c
index b09f479..8fe80ea 100644
--- a/sys/alpha/alpha/autoconf.c
+++ b/sys/alpha/alpha/autoconf.c
@@ -177,7 +177,7 @@ configure(void *dummy)
 {
 	configure_start();
 
-	device_add_child(root_bus, platform.iobus, 0, 0);
+	device_add_child(root_bus, platform.iobus, 0);
 
 	root_bus_configure();
 
diff --git a/sys/alpha/pci/apecs.c b/sys/alpha/pci/apecs.c
index ea1897e..d23df8a 100644
--- a/sys/alpha/pci/apecs.c
+++ b/sys/alpha/pci/apecs.c
@@ -574,7 +574,7 @@ apecs_probe(device_t dev)
 	isa_init_intr();
 	apecs_init_sgmap();
 
-	device_add_child(dev, "pcib", 0, 0);
+	device_add_child(dev, "pcib", 0);
 
 	return 0;
 }
diff --git a/sys/alpha/pci/apecs_pci.c b/sys/alpha/pci/apecs_pci.c
index 7a0573b..bb1b8bd 100644
--- a/sys/alpha/pci/apecs_pci.c
+++ b/sys/alpha/pci/apecs_pci.c
@@ -42,7 +42,7 @@ apecs_pcib_probe(device_t dev)
 {
 	device_set_desc(dev, "2107x PCI host bus adapter");
 
-	device_add_child(dev, "pci", 0, 0);
+	device_add_child(dev, "pci", 0);
 
 	return 0;
 }
diff --git a/sys/alpha/pci/cia.c b/sys/alpha/pci/cia.c
index f89de15..55a4750 100644
--- a/sys/alpha/pci/cia.c
+++ b/sys/alpha/pci/cia.c
@@ -897,7 +897,7 @@ cia_probe(device_t dev)
 	isa_init_intr();
 	cia_init_sgmap();
 
-	device_add_child(dev, "pcib", 0, 0);
+	device_add_child(dev, "pcib", 0);
 
 	return 0;
 }
diff --git a/sys/alpha/pci/cia_pci.c b/sys/alpha/pci/cia_pci.c
index 73da41a..32bf645 100644
--- a/sys/alpha/pci/cia_pci.c
+++ b/sys/alpha/pci/cia_pci.c
@@ -42,7 +42,7 @@ cia_pcib_probe(device_t dev)
 {
 	device_set_desc(dev, "2117x PCI host bus adapter");
 
-	device_add_child(dev, "pci", 0, 0);
+	device_add_child(dev, "pci", 0);
 
 	return 0;
 }
diff --git a/sys/alpha/pci/lca.c b/sys/alpha/pci/lca.c
index 5951332..c1b8082 100644
--- a/sys/alpha/pci/lca.c
+++ b/sys/alpha/pci/lca.c
@@ -460,7 +460,7 @@ lca_probe(device_t dev)
 	isa_init_intr();
 	lca_init_sgmap();
 
-	device_add_child(dev, "pcib", 0, 0);
+	device_add_child(dev, "pcib", 0);
 
 	return 0;
 }
diff --git a/sys/alpha/pci/lca_pci.c b/sys/alpha/pci/lca_pci.c
index 10a5a2a..1765c3b 100644
--- a/sys/alpha/pci/lca_pci.c
+++ b/sys/alpha/pci/lca_pci.c
@@ -42,7 +42,7 @@ lca_pcib_probe(device_t dev)
 {
 	device_set_desc(dev, "21066 PCI host bus adapter");
 
-	device_add_child(dev, "pci", 0, 0);
+	device_add_child(dev, "pci", 0);
 
 	return 0;
 }
diff --git a/sys/alpha/pci/tsunami.c b/sys/alpha/pci/tsunami.c
index 43b8b4d..c9cb3b5 100644
--- a/sys/alpha/pci/tsunami.c
+++ b/sys/alpha/pci/tsunami.c
@@ -538,6 +538,7 @@ tsunami_init()
 static int
 tsunami_probe(device_t dev)
 {
+	device_t child;
 	int *hose;
 	int i;
 	if (tsunami0)
@@ -555,7 +556,8 @@ tsunami_probe(device_t dev)
 	for(i = 0; i < num_pchips; i++) {
 		hose = malloc(sizeof(int), M_DEVBUF, M_NOWAIT);
 		*hose = i;
-		device_add_child(dev, "pcib", i, hose);
+		child = device_add_child(dev, "pcib", i);
+		device_set_ivars(child, hose);
 		pchip_init(pchip[i], i);		
 	}
 
diff --git a/sys/alpha/pci/tsunami_pci.c b/sys/alpha/pci/tsunami_pci.c
index 634260c..87ea867 100644
--- a/sys/alpha/pci/tsunami_pci.c
+++ b/sys/alpha/pci/tsunami_pci.c
@@ -70,7 +70,7 @@ tsunami_pcib_probe(device_t dev)
 
 	device_set_desc(dev, "21271 PCI host bus adapter");
 
-	child = device_add_child(dev, "pci", -1, 0);
+	child = device_add_child(dev, "pci", -1);
 
 	if(hoseno)
 		tsunami_hoses[hoseno] = device_get_unit(child);
diff --git a/sys/alpha/tc/ioasic.c b/sys/alpha/tc/ioasic.c
index c6dd884..2cfe603 100644
--- a/sys/alpha/tc/ioasic.c
+++ b/sys/alpha/tc/ioasic.c
@@ -173,6 +173,7 @@ ioasic_probe(device_t dev)
 static int
 ioasic_attach(device_t dev)
 {
+	device_t child;
 	struct ioasic_softc* sc = IOASIC_SOFTC(dev);
 	struct tc_attach_args *ta = device_get_ivars(dev);
 	device_t parent = device_get_parent(dev);
@@ -226,7 +227,10 @@ ioasic_attach(device_t dev)
 
         for (i = 0; i < ioasic_ndevs; i++) {
 		ioasic_devs[i].iada_addr = sc->sc_base + ioasic_devs[i].iad_offset;
-		device_probe_and_attach(device_add_child(dev, ioasic_devs[i].iad_modname, -1, &ioasic_devs[i]));
+
+		child = device_add_child(dev, ioasic_devs[i].iad_modname, -1);
+		device_set_ivars(child, &ioasic_devs[i]);
+		device_probe_and_attach(child);
 	}
 	return 0;
 }
diff --git a/sys/alpha/tc/tc.c b/sys/alpha/tc/tc.c
index 16d1552..7c34306 100644
--- a/sys/alpha/tc/tc.c
+++ b/sys/alpha/tc/tc.c
@@ -612,7 +612,8 @@ tc_attach(device_t dev)
                 ta->ta_cookie = builtin->tcb_cookie;
                 ta->ta_busspeed = sc->sc_speed;
 
-		child = device_add_child(dev, builtin->tcb_modname, 0, ta);
+		child = device_add_child(dev, builtin->tcb_modname, 0);
+		device_set_ivars(child, ta);
 		device_probe_and_attach(child);
 	}
 
diff --git a/sys/alpha/tc/tcasic.c b/sys/alpha/tc/tcasic.c
index 493b5ac..8a600f1 100644
--- a/sys/alpha/tc/tcasic.c
+++ b/sys/alpha/tc/tcasic.c
@@ -82,7 +82,7 @@ tcasic_probe(device_t dev)
 		return ENXIO;
 	tcasic0 = dev;
 	device_set_desc(dev, "Turbochannel Host Bus Adapter");
-	tc0 = device_add_child(dev, "tc", 0, 0);
+	tc0 = device_add_child(dev, "tc", 0);
 	return 0;
 }
 
diff --git a/sys/alpha/tc/tcds.c b/sys/alpha/tc/tcds.c
index 4cedfbf..2fe9292 100644
--- a/sys/alpha/tc/tcds.c
+++ b/sys/alpha/tc/tcds.c
@@ -150,6 +150,7 @@ tcds_attach(device_t dev)
 	struct tcds_softc* sc = TCDS_SOFTC(dev);
 	struct tc_attach_args *ta = device_get_ivars(dev);
 	device_t parent = device_get_parent(dev);
+	device_t child;
 	vm_offset_t regs,va;
 	u_long i;
 	struct tcds_slotconfig *slotc;
@@ -229,7 +230,9 @@ tcds_attach(device_t dev)
 	    tcdsdev->tcdsda_freq = 25000000;                 /* XXX */
 
 	    tcds_scsi_reset(tcdsdev->tcdsda_sc);
-	    device_probe_and_attach(device_add_child(dev, "esp", -1, tcdsdev));
+	    child = device_add_child(dev, "esp", -1);
+	    device_set_ivars(child, tcdsdev);
+	    device_probe_and_attach(child);
 	}
 
         /* the second SCSI chip isn't present on the 3000/300 series. */
@@ -248,7 +251,9 @@ tcds_attach(device_t dev)
 			tcdsdev->tcdsda_id = 7;                  /* XXX */
 			tcdsdev->tcdsda_freq = 25000000;         /* XXX */
 			tcds_scsi_reset(tcdsdev->tcdsda_sc);
-			device_probe_and_attach(device_add_child(dev, "esp", -1, tcdsdev));
+			child = device_add_child(dev, "esp", -1);
+			device_set_ivars(child, tcdsdev);
+			device_probe_and_attach(child);
 		}
         }
 	return 0;
diff --git a/sys/alpha/tlsb/gbus.c b/sys/alpha/tlsb/gbus.c
index 4e08609..d8cb286 100644
--- a/sys/alpha/tlsb/gbus.c
+++ b/sys/alpha/tlsb/gbus.c
@@ -112,6 +112,7 @@ static driver_t gbus_driver = {
 static int
 gbus_probe(device_t dev)
 {
+	device_t child;
 	struct gbus_device *gdev;
 
 	/*
@@ -122,8 +123,10 @@ gbus_probe(device_t dev)
 	if (!TLDEV_ISCPU(tlsb_get_dtype(dev)))
 		return ENXIO;
 
-	for (gdev = gbus_children; gdev->gd_name; gdev++)
-		device_add_child(dev, gdev->gd_name, -1, gdev);
+	for (gdev = gbus_children; gdev->gd_name; gdev++) {
+		child = device_add_child(dev, gdev->gd_name, -1);
+		device_set_ivars(child, gdev);
+	}
 
 	return 0;
 }
diff --git a/sys/alpha/tlsb/kftxx.c b/sys/alpha/tlsb/kftxx.c
index 0daf0aa..8450c2b 100644
--- a/sys/alpha/tlsb/kftxx.c
+++ b/sys/alpha/tlsb/kftxx.c
@@ -104,6 +104,7 @@ static driver_t kft_driver = {
 static int
 kft_probe(device_t dev)
 {
+	device_t child;
 	struct kft_softc *sc = (struct kft_softc *) device_get_softc(dev);
 	struct kft_device* kd;
 	int hoseno;
@@ -145,7 +146,8 @@ kft_probe(device_t dev)
 		kd->kd_node = sc->sc_node;
 		kd->kd_dtype = sc->sc_dtype;
 		kd->kd_hosenum = hoseno;
-		device_add_child(dev, kd->kd_name, -1, kd);
+		child = device_add_child(dev, kd->kd_name, -1);
+		device_set_ivars(child, kd);
 	}
 
 	return 0;
diff --git a/sys/alpha/tlsb/tlsb.c b/sys/alpha/tlsb/tlsb.c
index 31a0b42..b6790f7 100644
--- a/sys/alpha/tlsb/tlsb.c
+++ b/sys/alpha/tlsb/tlsb.c
@@ -206,7 +206,8 @@ tlsb_probe(device_t dev)
 		tdev->td_swrev = TLDEV_SWREV(tldev);
 		tdev->td_hwrev = TLDEV_HWREV(tldev);
 
-		child = device_add_child(dev, NULL, -1, tdev);
+		child = device_add_child(dev, NULL, -1);
+		device_set_ivars(child, tdev);
 		device_set_desc(child, tlsb_node_type_str(tdev->td_dtype));
 
 		/*
diff --git a/sys/alpha/tlsb/zs_tlsb.c b/sys/alpha/tlsb/zs_tlsb.c
index 7b22012..7a881b4 100644
--- a/sys/alpha/tlsb/zs_tlsb.c
+++ b/sys/alpha/tlsb/zs_tlsb.c
@@ -430,8 +430,8 @@ zsc_tlsb_probe(device_t dev)
 	/*
 	 * Add channel A and channel B
 	 */
-	device_add_child(dev, "zs", 0, (void*) 0);
-	device_add_child(dev, "zs", 1, (void*) 0);
+	device_add_child(dev, "zs", 0);
+	device_add_child(dev, "zs", 1);
 
 	return 0;
 }
diff --git a/sys/amd64/amd64/autoconf.c b/sys/amd64/amd64/autoconf.c
index 4f12924..877b326 100644
--- a/sys/amd64/amd64/autoconf.c
+++ b/sys/amd64/amd64/autoconf.c
@@ -136,7 +136,7 @@ configure(dummy)
 #endif /* APIC_IO */
 
 	/* nexus0 is the top of the i386 device tree */
-	device_add_child(root_bus, "nexus", 0, 0);
+	device_add_child(root_bus, "nexus", 0);
 
 	/* initialize new bus architecture */
 	root_bus_configure();
diff --git a/sys/amd64/amd64/legacy.c b/sys/amd64/amd64/legacy.c
index ec9c186f..fda15bb 100644
--- a/sys/amd64/amd64/legacy.c
+++ b/sys/amd64/amd64/legacy.c
@@ -202,25 +202,26 @@ nexus_attach(device_t dev)
 	 * connection points now so they show up "on motherboard".
 	 */
 	if (!devclass_get_device(devclass_find("eisa"), 0)) {
-		child = device_add_child(dev, "eisa", 0, 0);
+		child = device_add_child(dev, "eisa", 0);
 		if (child == NULL)
 			panic("nexus_attach eisa");
 		device_probe_and_attach(child);
 	}
 #if NMCA > 0
 	if (!devclass_get_device(devclass_find("mca"), 0)) {
-        	child = device_add_child(dev, "mca", 0, 0);
+        	child = device_add_child(dev, "mca", 0);
         	if (child == 0)
                 	panic("nexus_probe mca");
 		device_probe_and_attach(child);
 	}
 #endif
 	if (!devclass_get_device(devclass_find("isa"), 0)) {
-		child = device_add_child(dev, "isa", 0, 0);
+		child = device_add_child(dev, "isa", 0);
 		if (child == NULL)
 			panic("nexus_attach isa");
 		device_probe_and_attach(child);
 	}
+
 	return 0;
 }
 
@@ -238,7 +239,7 @@ nexus_print_child(device_t bus, device_t child)
 static device_t
 nexus_add_child(device_t bus, int order, const char *name, int unit)
 {
-	return device_add_child_ordered(bus, order, name, unit, 0);
+	return device_add_child_ordered(bus, order, name, unit);
 }
 
 /*
diff --git a/sys/amd64/amd64/nexus.c b/sys/amd64/amd64/nexus.c
index ec9c186f..fda15bb 100644
--- a/sys/amd64/amd64/nexus.c
+++ b/sys/amd64/amd64/nexus.c
@@ -202,25 +202,26 @@ nexus_attach(device_t dev)
 	 * connection points now so they show up "on motherboard".
 	 */
 	if (!devclass_get_device(devclass_find("eisa"), 0)) {
-		child = device_add_child(dev, "eisa", 0, 0);
+		child = device_add_child(dev, "eisa", 0);
 		if (child == NULL)
 			panic("nexus_attach eisa");
 		device_probe_and_attach(child);
 	}
 #if NMCA > 0
 	if (!devclass_get_device(devclass_find("mca"), 0)) {
-        	child = device_add_child(dev, "mca", 0, 0);
+        	child = device_add_child(dev, "mca", 0);
         	if (child == 0)
                 	panic("nexus_probe mca");
 		device_probe_and_attach(child);
 	}
 #endif
 	if (!devclass_get_device(devclass_find("isa"), 0)) {
-		child = device_add_child(dev, "isa", 0, 0);
+		child = device_add_child(dev, "isa", 0);
 		if (child == NULL)
 			panic("nexus_attach isa");
 		device_probe_and_attach(child);
 	}
+
 	return 0;
 }
 
@@ -238,7 +239,7 @@ nexus_print_child(device_t bus, device_t child)
 static device_t
 nexus_add_child(device_t bus, int order, const char *name, int unit)
 {
-	return device_add_child_ordered(bus, order, name, unit, 0);
+	return device_add_child_ordered(bus, order, name, unit);
 }
 
 /*
diff --git a/sys/amd64/pci/pci_bus.c b/sys/amd64/pci/pci_bus.c
index a640e14..609d416 100644
--- a/sys/amd64/pci/pci_bus.c
+++ b/sys/amd64/pci/pci_bus.c
@@ -478,7 +478,7 @@ static int
 nexus_pcib_probe(device_t dev)
 {
 	if (pci_cfgopen() != 0) {
-		device_add_child(dev, "pci", device_get_unit(dev), 0);
+		device_add_child(dev, "pci", device_get_unit(dev));
 		return 0;
 	}
 	return ENXIO;
diff --git a/sys/amd64/pci/pci_cfgreg.c b/sys/amd64/pci/pci_cfgreg.c
index a640e14..609d416 100644
--- a/sys/amd64/pci/pci_cfgreg.c
+++ b/sys/amd64/pci/pci_cfgreg.c
@@ -478,7 +478,7 @@ static int
 nexus_pcib_probe(device_t dev)
 {
 	if (pci_cfgopen() != 0) {
-		device_add_child(dev, "pci", device_get_unit(dev), 0);
+		device_add_child(dev, "pci", device_get_unit(dev));
 		return 0;
 	}
 	return ENXIO;
diff --git a/sys/dev/amr/amr.c b/sys/dev/amr/amr.c
index bdb3c02..d32057b 100644
--- a/sys/dev/amr/amr.c
+++ b/sys/dev/amr/amr.c
@@ -439,9 +439,10 @@ amr_startup(struct amr_softc *sc)
 	    }
 	    dr->al_cylinders = dr->al_size / (dr->al_heads * dr->al_sectors);
 	    
-	    dr->al_disk = device_add_child(sc->amr_dev, NULL, -1, dr);
+	    dr->al_disk = device_add_child(sc->amr_dev, NULL, -1);
 	    if (dr->al_disk == 0)
 		device_printf(sc->amr_dev, "device_add_child failed\n");
+	    device_set_ivars(dr->al_disk, dr);
 	}
     }
     
diff --git a/sys/dev/atkbdc/atkbdc_isa.c b/sys/dev/atkbdc/atkbdc_isa.c
index eae6e14..9829f2b 100644
--- a/sys/dev/atkbdc/atkbdc_isa.c
+++ b/sys/dev/atkbdc/atkbdc_isa.c
@@ -137,7 +137,8 @@ atkbdc_add_device(device_t dev, const char *name, int unit)
 	else
 		kdev->flags = 0;
 
-	child = device_add_child(dev, name, unit, kdev);
+	child = device_add_child(dev, name, unit);
+	device_set_ivars(child, kdev);
 }
 
 static int
diff --git a/sys/dev/atkbdc/atkbdc_subr.c b/sys/dev/atkbdc/atkbdc_subr.c
index eae6e14..9829f2b 100644
--- a/sys/dev/atkbdc/atkbdc_subr.c
+++ b/sys/dev/atkbdc/atkbdc_subr.c
@@ -137,7 +137,8 @@ atkbdc_add_device(device_t dev, const char *name, int unit)
 	else
 		kdev->flags = 0;
 
-	child = device_add_child(dev, name, unit, kdev);
+	child = device_add_child(dev, name, unit);
+	device_set_ivars(child, kdev);
 }
 
 static int
diff --git a/sys/dev/bktr/bktr_i2c.c b/sys/dev/bktr/bktr_i2c.c
index 7cd0ba0..43a5f35 100644
--- a/sys/dev/bktr/bktr_i2c.c
+++ b/sys/dev/bktr/bktr_i2c.c
@@ -159,10 +159,10 @@ bt848_i2c_attach(int unit, bt848_ptr_t base, struct bktr_i2c_softc *i2c_sc)
 	btdata[unit].base = base;
 
 	/* XXX add the I2C interface to the root_bus until pcibus is ready */
-	interface = device_add_child(root_bus, "bti2c", unit, NULL);
+	interface = device_add_child(root_bus, "bti2c", unit);
 
 	/* add bit-banging generic code onto bti2c interface */
-	bitbang = device_add_child(interface, "iicbb", -1, NULL);
+	bitbang = device_add_child(interface, "iicbb", -1);
 
 	/* probe and attach the interface, we need it NOW
 	 * bit-banging code is also probed and attached */
diff --git a/sys/dev/eisa/eisaconf.c b/sys/dev/eisa/eisaconf.c
index d602305..59f553a 100644
--- a/sys/dev/eisa/eisaconf.c
+++ b/sys/dev/eisa/eisaconf.c
@@ -152,6 +152,7 @@ eisa_probe(device_t dev)
 {
 	int i,slot;
 	struct eisa_device *e_dev;
+	device_t child;
 	int eisaBase = 0xc80;
 	eisa_id_t eisa_id;
 	int devices_found = 0;
@@ -188,7 +189,8 @@ eisa_probe(device_t dev)
 		LIST_INIT(&(e_dev->ioconf.maddrs));
 		TAILQ_INIT(&(e_dev->ioconf.irqs));
 
-		device_add_child(dev, NULL, -1, e_dev);
+		child = device_add_child(dev, NULL, -1);
+		device_set_ivars(child, e_dev);
 	}
 
 	/*
diff --git a/sys/dev/fdc/fdc.c b/sys/dev/fdc/fdc.c
index da131e1..69e9795 100644
--- a/sys/dev/fdc/fdc.c
+++ b/sys/dev/fdc/fdc.c
@@ -772,7 +772,8 @@ fdc_add_device(device_t dev, const char *name, int unit)
 		return;
 	if (resource_int_value(name, unit, "drive", ivar) != 0)
 		*ivar = 0;
-	child = device_add_child(dev, name, unit, ivar);
+	child = device_add_child(dev, name, unit);
+	device_set_ivars(child, ivar);
 	if (child == 0)
 		return;
 	if (resource_int_value(name, unit, "disabled", &disabled) == 0
diff --git a/sys/dev/ida/ida.c b/sys/dev/ida/ida.c
index 769205f..ae25391 100644
--- a/sys/dev/ida/ida.c
+++ b/sys/dev/ida/ida.c
@@ -252,7 +252,7 @@ ida_attach(struct ida_softc *ida)
 	ida->num_drives = cinfo.num_drvs;
 
 	for (i = 0; i < ida->num_drives; i++)
-		device_add_child(ida->dev, "id", i, NULL);
+		device_add_child(ida->dev, "id", i);
 
 	bus_generic_attach(ida->dev);
 
diff --git a/sys/dev/iicbus/iicbus.c b/sys/dev/iicbus/iicbus.c
index 26912fc..45a32d4d 100644
--- a/sys/dev/iicbus/iicbus.c
+++ b/sys/dev/iicbus/iicbus.c
@@ -203,8 +203,8 @@ iicbus_attach(device_t dev)
 		}
 
 		if (iicdev->iicd_alive) {
-			child = device_add_child(dev, iicdev->iicd_name,
-								-1, iicdev);
+			child = device_add_child(dev, iicdev->iicd_name, -1);
+			device_set_ivars(child, iicdev);
 			device_set_desc(child, iicdev->iicd_desc);
 		}
 	}
diff --git a/sys/dev/iicbus/iiconf.c b/sys/dev/iicbus/iiconf.c
index 52e92f7..1fc07bf 100644
--- a/sys/dev/iicbus/iiconf.c
+++ b/sys/dev/iicbus/iiconf.c
@@ -63,7 +63,7 @@ iicbus_alloc_bus(device_t parent)
 	device_t child;
 
 	/* add the bus to the parent */
-	child = device_add_child(parent, "iicbus", -1, NULL);
+	child = device_add_child(parent, "iicbus", -1);
 
 	return (child);
 }
diff --git a/sys/dev/mca/mca_bus.c b/sys/dev/mca/mca_bus.c
index f105ea1..a2dd456 100644
--- a/sys/dev/mca/mca_bus.c
+++ b/sys/dev/mca/mca_bus.c
@@ -245,6 +245,7 @@ mca_add_iospace (dev, iobase, iosize)
 static int
 mca_probe (device_t dev)
 {
+	device_t		child;
 	struct mca_device *	m_dev = NULL;
 	int			devices_found = 0;
 	u_int8_t		slot;
@@ -307,7 +308,8 @@ mca_probe (device_t dev)
 
 		resource_list_init(&(m_dev->rl));
 
-		device_add_child(dev, NULL, -1, m_dev);
+		child = device_add_child(dev, NULL, -1);
+		device_set_ivars(child, m_dev);
 
 		m_dev = NULL;
 	}
diff --git a/sys/dev/mii/mii.c b/sys/dev/mii/mii.c
index 46cdc22..b3f40e2 100644
--- a/sys/dev/mii/mii.c
+++ b/sys/dev/mii/mii.c
@@ -142,7 +142,8 @@ int miibus_probe(dev)
 		args = malloc(sizeof(struct mii_attach_args),
 		    M_DEVBUF, M_NOWAIT);
 		bcopy((char *)&ma, (char *)args, sizeof(ma));
-		child = device_add_child(dev, NULL, -1, args);
+		child = device_add_child(dev, NULL, -1);
+		device_set_ivars(child, args);
 	}
 
 	if (child == NULL)
@@ -250,7 +251,8 @@ int mii_phy_probe(dev, child, ifmedia_upd, ifmedia_sts)
 	v = malloc(sizeof(vm_offset_t) * 2, M_DEVBUF, M_NOWAIT);
 	v[0] = ifmedia_upd;
 	v[1] = ifmedia_sts;
-	*child = device_add_child(dev, "miibus", -1, v);
+	*child = device_add_child(dev, "miibus", -1);
+	device_set_ivars(*child, v);
 
 	for (i = 0; i < MII_NPHY; i++) {
 		bmsr = MIIBUS_READREG(dev, i, MII_BMSR);
diff --git a/sys/dev/mlx/mlx.c b/sys/dev/mlx/mlx.c
index eccb788..ee099d2 100644
--- a/sys/dev/mlx/mlx.c
+++ b/sys/dev/mlx/mlx.c
@@ -480,9 +480,10 @@ mlx_startup(struct mlx_softc *sc)
 		dr->ms_sectors = 63;
 		dr->ms_cylinders = dr->ms_size / (255 * 63);
 	    }
-	    dr->ms_disk =  device_add_child(sc->mlx_dev, /*"mlxd"*/NULL, -1, dr);
+	    dr->ms_disk =  device_add_child(sc->mlx_dev, /*"mlxd"*/NULL, -1);
 	    if (dr->ms_disk == 0)
 		device_printf(sc->mlx_dev, "device_add_child failed\n");
+	    device_set_ivars(dr->ms_disk, dr);
 	}
     }
     free(mes, M_DEVBUF);
diff --git a/sys/dev/pccard/pccard.c b/sys/dev/pccard/pccard.c
index ca1748d..39c939c 100644
--- a/sys/dev/pccard/pccard.c
+++ b/sys/dev/pccard/pccard.c
@@ -839,7 +839,7 @@ pccard_card_intrdebug(arg)
 static int
 pccard_add_children(device_t dev, int busno)
 {
-	device_add_child(dev, NULL, -1, NULL);
+	device_add_child(dev, NULL, -1);
 	return 0;
 }
 
diff --git a/sys/dev/pcf/pcf.c b/sys/dev/pcf/pcf.c
index 3cb86f7..1aeb7e6 100644
--- a/sys/dev/pcf/pcf.c
+++ b/sys/dev/pcf/pcf.c
@@ -164,7 +164,7 @@ pcfprobe_isa(struct isa_device *dvp)
 	pcfdata[npcf++] = pcf;
 
 	/* XXX add the pcf device to the root_bus until isa bus exists */
-	pcfdev = device_add_child(root_bus, "pcf", pcf->pcf_unit, NULL);
+	pcfdev = device_add_child(root_bus, "pcf", pcf->pcf_unit);
 
 	if (!pcfdev)
 		goto error;
diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c
index efb98d2..b4dd70b 100644
--- a/sys/dev/pci/pci.c
+++ b/sys/dev/pci/pci.c
@@ -1115,8 +1115,8 @@ pci_add_children(device_t dev, int busno)
 					pcifunchigh = 7;
 
 				pci_print_verbose(dinfo);
-				dinfo->cfg.dev =
-					device_add_child(dev, NULL, -1, dinfo);
+				dinfo->cfg.dev = device_add_child(dev, NULL, -1);
+				device_set_ivars(dinfo->cfg.dev, dinfo);
 				pci_add_resources(dinfo->cfg.dev, &dinfo->cfg);
 			}
 		}
diff --git a/sys/dev/ppbus/lpbb.c b/sys/dev/ppbus/lpbb.c
index bf28807..7d4ba59 100644
--- a/sys/dev/ppbus/lpbb.c
+++ b/sys/dev/ppbus/lpbb.c
@@ -134,7 +134,7 @@ lpbb_attach(device_t dev)
 	device_t bitbang, iicbus;
 	
 	/* add generic bit-banging code */
-	bitbang = device_add_child(dev, "iicbb", -1, NULL);
+	bitbang = device_add_child(dev, "iicbb", -1);
 
 	/* add the iicbus to the tree */
 	iicbus = iicbus_alloc_bus(bitbang);
@@ -191,7 +191,7 @@ static int
 lpbb_ppb_attach(struct ppb_device *dev)
 {
 	/* add the parallel port I2C interface to the bus tree */
-	if (!device_add_child(root_bus, "lpbb", dev->id_unit, NULL))
+	if (!device_add_child(root_bus, "lpbb", dev->id_unit))
 		return (0);
 
 	return (1);
diff --git a/sys/dev/smbus/smbconf.c b/sys/dev/smbus/smbconf.c
index 1d44ef3..1afb7e9 100644
--- a/sys/dev/smbus/smbconf.c
+++ b/sys/dev/smbus/smbconf.c
@@ -91,7 +91,7 @@ smbus_alloc_bus(device_t parent)
 	device_t child;
 
 	/* add the bus to the parent */
-	child = device_add_child(parent, "smbus", -1, NULL);
+	child = device_add_child(parent, "smbus", -1);
 
 	return (child);
 }
diff --git a/sys/dev/smbus/smbus.c b/sys/dev/smbus/smbus.c
index 1107992..a1d3634 100644
--- a/sys/dev/smbus/smbus.c
+++ b/sys/dev/smbus/smbus.c
@@ -113,8 +113,8 @@ smbus_attach(device_t dev)
 		device_t child;
 
 		if (devclass_find(smbdev->smbd_name)) {
-			child = device_add_child(dev, smbdev->smbd_name,
-								-1, smbdev);
+			child = device_add_child(dev, smbdev->smbd_name, -1);
+			device_set_ivars(child, smbdev);
 			device_set_desc(child, smbdev->smbd_desc);
 		} else if (bootverbose)
 			printf("smbus: %s devclass not found\n",
diff --git a/sys/dev/sound/isa/gusc.c b/sys/dev/sound/isa/gusc.c
index 93fa250..b6de776 100644
--- a/sys/dev/sound/isa/gusc.c
+++ b/sys/dev/sound/isa/gusc.c
@@ -112,6 +112,7 @@ static devclass_t gusc_devclass;
 static int
 gusc_probe(device_t dev)
 {
+	device_t child;
 	u_int32_t vend_id, logical_id;
 	char *s;
 	struct sndcard_func *func;
@@ -133,7 +134,8 @@ gusc_probe(device_t dev)
 				return (ENOMEM);
 			bzero(func, sizeof(*func));
 			func->func = SCF_PCM;
-			device_add_child(dev, "pcm", -1, func);
+			child = device_add_child(dev, "pcm", -1);
+			device_set_ivars(child, func);
 			break;
 #if notyet
 		case LOGICALID_OPL:
@@ -143,7 +145,8 @@ gusc_probe(device_t dev)
 				return (ENOMEM);
 			bzero(func, sizeof(*func));
 			func->func = SCF_SYNTH;
-			device_add_child(dev, "midi", -1, func);
+			child = device_add_child(dev, "midi", -1);
+			device_set_ivars(child, func);
 			break;
 		case LOGICALID_MIDI:
 			s = "Gravis UltraSound Plug & Play MIDI";
@@ -152,7 +155,8 @@ gusc_probe(device_t dev)
 				return (ENOMEM);
 			bzero(func, sizeof(*func));
 			func->func = SCF_MIDI;
-			device_add_child(dev, "midi", -1, func);
+			child = device_add_child(dev, "midi", -1);
+			device_set_ivars(child, func);
 			break;
 #endif /* notyet */
 		}
@@ -186,6 +190,7 @@ port_rd(struct resource *r, int i)
 static int
 gusisa_probe(device_t dev)
 {
+	device_t child;
 	struct resource *res, *res2;
 	int base, rid, rid2, s, flags;
 	unsigned char val;
@@ -283,7 +288,8 @@ gusisa_probe(device_t dev)
 			return ENOMEM;
 		bzero(func, sizeof *func);
 		func->func = SCF_MIDI;
-		device_add_child(dev, "midi", -1, func);
+		child = device_add_child(dev, "midi", -1);
+		device_set_ivars(child, func);
 #endif /* notyet */
 
 		func = malloc(sizeof(struct sndcard_func), M_DEVBUF, M_NOWAIT);
@@ -292,7 +298,8 @@ gusisa_probe(device_t dev)
 		else {
 			bzero(func, sizeof *func);
 			func->func = SCF_PCM;
-			device_add_child(dev, "pcm", -1, func);
+			child = device_add_child(dev, "pcm", -1);
+			device_set_ivars(child, func);
 		}
 		device_set_desc(dev, "Gravis UltraSound MAX");
 		return 0;
diff --git a/sys/dev/sound/isa/sbc.c b/sys/dev/sound/isa/sbc.c
index 8f3a4ee..7e9080e 100644
--- a/sys/dev/sound/isa/sbc.c
+++ b/sys/dev/sound/isa/sbc.c
@@ -86,6 +86,7 @@ static devclass_t sbc_devclass;
 static int
 sbc_probe(device_t dev)
 {
+	device_t child;
 	u_int32_t vend_id, logical_id, vend_id2;
 	char *s;
 	struct sndcard_func *func;
@@ -177,7 +178,8 @@ sbc_probe(device_t dev)
 			return (ENOMEM);
 		bzero(func, sizeof(*func));
 		func->func = SCF_PCM;
-		device_add_child(dev, "pcm", -1, func);
+		child = device_add_child(dev, "pcm", -1);
+		device_set_ivars(child, func);
 
 #if notyet
 		/* Midi Interface */
@@ -186,7 +188,8 @@ sbc_probe(device_t dev)
 			return (ENOMEM);
 		bzero(func, sizeof(*func));
 		func->func = SCF_MIDI;
-		device_add_child(dev, "midi", -1, func);
+		child = device_add_child(dev, "midi", -1);
+		device_set_ivars(child, func);
 
 		/* OPL FM Synthesizer */
 		func = malloc(sizeof(struct sndcard_func), M_DEVBUF, M_NOWAIT);
@@ -194,7 +197,8 @@ sbc_probe(device_t dev)
 			return (ENOMEM);
 		bzero(func, sizeof(*func));
 		func->func = SCF_SYNTH;
-		device_add_child(dev, "midi", -1, func);
+		child = device_add_child(dev, "midi", -1);
+		device_set_ivars(child, func);
 #endif /* notyet */
 
 		return (0);
diff --git a/sys/dev/sound/pci/csa.c b/sys/dev/sound/pci/csa.c
index 1637143..eebeda6 100644
--- a/sys/dev/sound/pci/csa.c
+++ b/sys/dev/sound/pci/csa.c
@@ -91,6 +91,7 @@ static devclass_t csa_devclass;
 static int
 csa_probe(device_t dev)
 {
+	device_t child;
 	char *s;
 	struct sndcard_func *func;
 
@@ -119,7 +120,8 @@ csa_probe(device_t dev)
 			return (ENOMEM);
 		bzero(func, sizeof(*func));
 		func->func = SCF_PCM;
-		device_add_child(dev, "pcm", -1, func);
+		child = device_add_child(dev, "pcm", -1);
+		device_set_ivars(child, func);
 
 #if notyet
 		/* Midi Interface */
@@ -128,7 +130,8 @@ csa_probe(device_t dev)
 			return (ENOMEM);
 		bzero(func, sizeof(*func));
 		func->func = SCF_MIDI;
-		device_add_child(dev, "midi", -1, func);
+		child = device_add_child(dev, "midi", -1);
+		device_set_ivars(child, func);
 #endif /* notyet */
 
 		return (0);
diff --git a/sys/dev/usb/ohci_pci.c b/sys/dev/usb/ohci_pci.c
index 8e1378b..f8c4964 100644
--- a/sys/dev/usb/ohci_pci.c
+++ b/sys/dev/usb/ohci_pci.c
@@ -168,7 +168,8 @@ ohci_pci_attach(device_t self)
 		return ENOMEM;
 	}
 
-	usbus = device_add_child(self, "usb", -1, sc);
+	usbus = device_add_child(self, "usb", -1);
+	device_set_ivars(usbus, sc);
 	if (!usbus) {
 		device_printf(self, "could not add USB device\n");
 		return ENOMEM;
diff --git a/sys/dev/usb/uhci_pci.c b/sys/dev/usb/uhci_pci.c
index 9285174..0857f16 100644
--- a/sys/dev/usb/uhci_pci.c
+++ b/sys/dev/usb/uhci_pci.c
@@ -181,7 +181,8 @@ uhci_pci_attach(device_t self)
 		return ENOMEM;
 	}
 		
-	usbus = device_add_child(self, "usb", -1, sc);
+	usbus = device_add_child(self, "usb", -1);
+	device_set_ivars(usbus, sc);
 	if (!usbus) {
 		device_printf(self, "could not add USB device\n");
 		return ENOMEM;
diff --git a/sys/dev/usb/usb_subr.c b/sys/dev/usb/usb_subr.c
index 0aedc62..46c2e8b 100644
--- a/sys/dev/usb/usb_subr.c
+++ b/sys/dev/usb/usb_subr.c
@@ -747,7 +747,8 @@ usbd_probe_and_attach(parent, dev, port, addr)
 	 * during probe and attach. Should be changed however.
 	 */
 	device_t bdev;
-	bdev = device_add_child(parent, NULL, -1, &uaa);
+	bdev = device_add_child(parent, NULL, -1);
+	device_set_ivars(bdev, &uaa);
 	if (!bdev) {
 	    printf("%s: Device creation failed\n", USBDEVNAME(dev->bus->bdev));
 	    return (USBD_INVAL);
@@ -828,8 +829,9 @@ usbd_probe_and_attach(parent, dev, port, addr)
 				ifaces[i] = 0; /* consumed */
 
 #if defined(__FreeBSD__)
-				/* create another child for the next iface */
-				bdev = device_add_child(parent, NULL, -1,&uaa);
+				/* create another device for the next iface */
+				bdev = device_add_child(parent, NULL, -1);
+				device_set_ivars(bdev, &uaa);
 				if (!bdev) {
 					printf("%s: Device creation failed\n",
 					USBDEVNAME(dev->bus->bdev));
diff --git a/sys/i386/eisa/eisaconf.c b/sys/i386/eisa/eisaconf.c
index d602305..59f553a 100644
--- a/sys/i386/eisa/eisaconf.c
+++ b/sys/i386/eisa/eisaconf.c
@@ -152,6 +152,7 @@ eisa_probe(device_t dev)
 {
 	int i,slot;
 	struct eisa_device *e_dev;
+	device_t child;
 	int eisaBase = 0xc80;
 	eisa_id_t eisa_id;
 	int devices_found = 0;
@@ -188,7 +189,8 @@ eisa_probe(device_t dev)
 		LIST_INIT(&(e_dev->ioconf.maddrs));
 		TAILQ_INIT(&(e_dev->ioconf.irqs));
 
-		device_add_child(dev, NULL, -1, e_dev);
+		child = device_add_child(dev, NULL, -1);
+		device_set_ivars(child, e_dev);
 	}
 
 	/*
diff --git a/sys/i386/i386/autoconf.c b/sys/i386/i386/autoconf.c
index 4f12924..877b326 100644
--- a/sys/i386/i386/autoconf.c
+++ b/sys/i386/i386/autoconf.c
@@ -136,7 +136,7 @@ configure(dummy)
 #endif /* APIC_IO */
 
 	/* nexus0 is the top of the i386 device tree */
-	device_add_child(root_bus, "nexus", 0, 0);
+	device_add_child(root_bus, "nexus", 0);
 
 	/* initialize new bus architecture */
 	root_bus_configure();
diff --git a/sys/i386/i386/legacy.c b/sys/i386/i386/legacy.c
index ec9c186f..fda15bb 100644
--- a/sys/i386/i386/legacy.c
+++ b/sys/i386/i386/legacy.c
@@ -202,25 +202,26 @@ nexus_attach(device_t dev)
 	 * connection points now so they show up "on motherboard".
 	 */
 	if (!devclass_get_device(devclass_find("eisa"), 0)) {
-		child = device_add_child(dev, "eisa", 0, 0);
+		child = device_add_child(dev, "eisa", 0);
 		if (child == NULL)
 			panic("nexus_attach eisa");
 		device_probe_and_attach(child);
 	}
 #if NMCA > 0
 	if (!devclass_get_device(devclass_find("mca"), 0)) {
-        	child = device_add_child(dev, "mca", 0, 0);
+        	child = device_add_child(dev, "mca", 0);
         	if (child == 0)
                 	panic("nexus_probe mca");
 		device_probe_and_attach(child);
 	}
 #endif
 	if (!devclass_get_device(devclass_find("isa"), 0)) {
-		child = device_add_child(dev, "isa", 0, 0);
+		child = device_add_child(dev, "isa", 0);
 		if (child == NULL)
 			panic("nexus_attach isa");
 		device_probe_and_attach(child);
 	}
+
 	return 0;
 }
 
@@ -238,7 +239,7 @@ nexus_print_child(device_t bus, device_t child)
 static device_t
 nexus_add_child(device_t bus, int order, const char *name, int unit)
 {
-	return device_add_child_ordered(bus, order, name, unit, 0);
+	return device_add_child_ordered(bus, order, name, unit);
 }
 
 /*
diff --git a/sys/i386/i386/nexus.c b/sys/i386/i386/nexus.c
index ec9c186f..fda15bb 100644
--- a/sys/i386/i386/nexus.c
+++ b/sys/i386/i386/nexus.c
@@ -202,25 +202,26 @@ nexus_attach(device_t dev)
 	 * connection points now so they show up "on motherboard".
 	 */
 	if (!devclass_get_device(devclass_find("eisa"), 0)) {
-		child = device_add_child(dev, "eisa", 0, 0);
+		child = device_add_child(dev, "eisa", 0);
 		if (child == NULL)
 			panic("nexus_attach eisa");
 		device_probe_and_attach(child);
 	}
 #if NMCA > 0
 	if (!devclass_get_device(devclass_find("mca"), 0)) {
-        	child = device_add_child(dev, "mca", 0, 0);
+        	child = device_add_child(dev, "mca", 0);
         	if (child == 0)
                 	panic("nexus_probe mca");
 		device_probe_and_attach(child);
 	}
 #endif
 	if (!devclass_get_device(devclass_find("isa"), 0)) {
-		child = device_add_child(dev, "isa", 0, 0);
+		child = device_add_child(dev, "isa", 0);
 		if (child == NULL)
 			panic("nexus_attach isa");
 		device_probe_and_attach(child);
 	}
+
 	return 0;
 }
 
@@ -238,7 +239,7 @@ nexus_print_child(device_t bus, device_t child)
 static device_t
 nexus_add_child(device_t bus, int order, const char *name, int unit)
 {
-	return device_add_child_ordered(bus, order, name, unit, 0);
+	return device_add_child_ordered(bus, order, name, unit);
 }
 
 /*
diff --git a/sys/i386/isa/pcf.c b/sys/i386/isa/pcf.c
index 3cb86f7..1aeb7e6 100644
--- a/sys/i386/isa/pcf.c
+++ b/sys/i386/isa/pcf.c
@@ -164,7 +164,7 @@ pcfprobe_isa(struct isa_device *dvp)
 	pcfdata[npcf++] = pcf;
 
 	/* XXX add the pcf device to the root_bus until isa bus exists */
-	pcfdev = device_add_child(root_bus, "pcf", pcf->pcf_unit, NULL);
+	pcfdev = device_add_child(root_bus, "pcf", pcf->pcf_unit);
 
 	if (!pcfdev)
 		goto error;
diff --git a/sys/i386/isa/pcibus.c b/sys/i386/isa/pcibus.c
index a640e14..609d416 100644
--- a/sys/i386/isa/pcibus.c
+++ b/sys/i386/isa/pcibus.c
@@ -478,7 +478,7 @@ static int
 nexus_pcib_probe(device_t dev)
 {
 	if (pci_cfgopen() != 0) {
-		device_add_child(dev, "pci", device_get_unit(dev), 0);
+		device_add_child(dev, "pci", device_get_unit(dev));
 		return 0;
 	}
 	return ENXIO;
diff --git a/sys/i386/pci/pci_bus.c b/sys/i386/pci/pci_bus.c
index a640e14..609d416 100644
--- a/sys/i386/pci/pci_bus.c
+++ b/sys/i386/pci/pci_bus.c
@@ -478,7 +478,7 @@ static int
 nexus_pcib_probe(device_t dev)
 {
 	if (pci_cfgopen() != 0) {
-		device_add_child(dev, "pci", device_get_unit(dev), 0);
+		device_add_child(dev, "pci", device_get_unit(dev));
 		return 0;
 	}
 	return ENXIO;
diff --git a/sys/i386/pci/pci_cfgreg.c b/sys/i386/pci/pci_cfgreg.c
index a640e14..609d416 100644
--- a/sys/i386/pci/pci_cfgreg.c
+++ b/sys/i386/pci/pci_cfgreg.c
@@ -478,7 +478,7 @@ static int
 nexus_pcib_probe(device_t dev)
 {
 	if (pci_cfgopen() != 0) {
-		device_add_child(dev, "pci", device_get_unit(dev), 0);
+		device_add_child(dev, "pci", device_get_unit(dev));
 		return 0;
 	}
 	return ENXIO;
diff --git a/sys/i386/pci/pci_pir.c b/sys/i386/pci/pci_pir.c
index a640e14..609d416 100644
--- a/sys/i386/pci/pci_pir.c
+++ b/sys/i386/pci/pci_pir.c
@@ -478,7 +478,7 @@ static int
 nexus_pcib_probe(device_t dev)
 {
 	if (pci_cfgopen() != 0) {
-		device_add_child(dev, "pci", device_get_unit(dev), 0);
+		device_add_child(dev, "pci", device_get_unit(dev));
 		return 0;
 	}
 	return ENXIO;
diff --git a/sys/isa/atkbdc_isa.c b/sys/isa/atkbdc_isa.c
index eae6e14..9829f2b 100644
--- a/sys/isa/atkbdc_isa.c
+++ b/sys/isa/atkbdc_isa.c
@@ -137,7 +137,8 @@ atkbdc_add_device(device_t dev, const char *name, int unit)
 	else
 		kdev->flags = 0;
 
-	child = device_add_child(dev, name, unit, kdev);
+	child = device_add_child(dev, name, unit);
+	device_set_ivars(child, kdev);
 }
 
 static int
diff --git a/sys/isa/fd.c b/sys/isa/fd.c
index da131e1..69e9795 100644
--- a/sys/isa/fd.c
+++ b/sys/isa/fd.c
@@ -772,7 +772,8 @@ fdc_add_device(device_t dev, const char *name, int unit)
 		return;
 	if (resource_int_value(name, unit, "drive", ivar) != 0)
 		*ivar = 0;
-	child = device_add_child(dev, name, unit, ivar);
+	child = device_add_child(dev, name, unit);
+	device_set_ivars(child, ivar);
 	if (child == 0)
 		return;
 	if (resource_int_value(name, unit, "disabled", &disabled) == 0
diff --git a/sys/isa/isa_common.c b/sys/isa/isa_common.c
index 9202754..a2478a1 100644
--- a/sys/isa/isa_common.c
+++ b/sys/isa/isa_common.c
@@ -519,6 +519,7 @@ isa_probe_children(device_t dev)
 static device_t
 isa_add_child(device_t dev, int order, const char *name, int unit)
 {
+	device_t child;
 	struct	isa_device *idev;
 
 	idev = malloc(sizeof(struct isa_device), M_ISADEV, M_NOWAIT);
@@ -529,7 +530,10 @@ isa_add_child(device_t dev, int order, const char *name, int unit)
 	resource_list_init(&idev->id_resources);
 	TAILQ_INIT(&idev->id_configs);
 
-	return device_add_child_ordered(dev, order, name, unit, idev);
+	child = device_add_child_ordered(dev, order, name, unit);
+ 	device_set_ivars(child, idev);
+
+	return child;
 }
 
 static void
diff --git a/sys/isa/vga_isa.c b/sys/isa/vga_isa.c
index 0f0d81a..73b58d1 100644
--- a/sys/isa/vga_isa.c
+++ b/sys/isa/vga_isa.c
@@ -173,7 +173,7 @@ isavga_attach(device_t dev)
 		(*vidsw[sc->adp->va_index]->diag)(sc->adp, bootverbose);
 
 #if experimental
-	device_add_child(dev, "fb", -1, NULL);
+	device_add_child(dev, "fb", -1);
 	bus_generic_attach(dev);
 #endif
 
diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c
index f144e60..b390b36 100644
--- a/sys/kern/subr_bus.c
+++ b/sys/kern/subr_bus.c
@@ -581,14 +581,12 @@ devclass_delete_device(devclass_t dc, device_t dev)
 }
 
 static device_t
-make_device(device_t parent, const char *name,
-	    int unit, void *ivars)
+make_device(device_t parent, const char *name, int unit)
 {
     device_t dev;
     devclass_t dc;
 
-    PDEBUG(("%s at %s as unit %d with%s ivars",
-    	    name, DEVICENAME(parent), unit, (ivars? "":"out")));
+    PDEBUG(("%s at %s as unit %d", name, DEVICENAME(parent), unit));
 
     if (name) {
 	dc = devclass_find_internal(name, TRUE);
@@ -622,7 +620,7 @@ make_device(device_t parent, const char *name,
 	dev->flags |= DF_FIXEDCLASS;
 	devclass_add_device(dc, dev);
     }
-    dev->ivars = ivars;
+    dev->ivars = NULL;
     dev->softc = NULL;
 
     dev->state = DS_NOTPRESENT;
@@ -644,22 +642,21 @@ device_print_child(device_t dev, device_t child)
 }
 
 device_t
-device_add_child(device_t dev, const char *name, int unit, void *ivars)
+device_add_child(device_t dev, const char *name, int unit)
 {
-    return device_add_child_ordered(dev, 0, name, unit, ivars);
+    return device_add_child_ordered(dev, 0, name, unit);
 }
 
 device_t
-device_add_child_ordered(device_t dev, int order,
-			 const char *name, int unit, void *ivars)
+device_add_child_ordered(device_t dev, int order, const char *name, int unit)
 {
     device_t child;
     device_t place;
 
-    PDEBUG(("%s at %s with order %d as unit %d with%s ivars",
-    	    name, DEVICENAME(dev), order, unit, (ivars? "":"out")));
+    PDEBUG(("%s at %s with order %d as unit %d",
+	    name, DEVICENAME(dev), order, unit));
 
-    child = make_device(dev, name, unit, ivars);
+    child = make_device(dev, name, unit);
     if (child == NULL)
 	return child;
     child->order = order;
@@ -984,6 +981,17 @@ device_get_ivars(device_t dev)
     return dev->ivars;
 }
 
+void
+device_set_ivars(device_t dev, void * ivars)
+{
+    if (!dev)
+	return;
+
+    dev->ivars = ivars;
+
+    return;
+}
+
 device_state_t
 device_get_state(device_t dev)
 {
diff --git a/sys/pc98/cbus/fdc.c b/sys/pc98/cbus/fdc.c
index 47063fc..8da7150 100644
--- a/sys/pc98/cbus/fdc.c
+++ b/sys/pc98/cbus/fdc.c
@@ -964,7 +964,8 @@ fdc_add_device(device_t dev, const char *name, int unit)
 		return;
 	if (resource_int_value(name, unit, "drive", ivar) != 0)
 		*ivar = 0;
-	child = device_add_child(dev, name, unit, ivar);
+	child = device_add_child(dev, name, unit);
+	device_set_ivars(child, ivar);
 	if (child == 0)
 		return;
 	if (resource_int_value(name, unit, "disabled", &disabled) == 0
diff --git a/sys/pc98/pc98/fd.c b/sys/pc98/pc98/fd.c
index 47063fc..8da7150 100644
--- a/sys/pc98/pc98/fd.c
+++ b/sys/pc98/pc98/fd.c
@@ -964,7 +964,8 @@ fdc_add_device(device_t dev, const char *name, int unit)
 		return;
 	if (resource_int_value(name, unit, "drive", ivar) != 0)
 		*ivar = 0;
-	child = device_add_child(dev, name, unit, ivar);
+	child = device_add_child(dev, name, unit);
+	device_set_ivars(child, ivar);
 	if (child == 0)
 		return;
 	if (resource_int_value(name, unit, "disabled", &disabled) == 0
diff --git a/sys/pccard/pccard.c b/sys/pccard/pccard.c
index 8eecad8..ec56bf5 100644
--- a/sys/pccard/pccard.c
+++ b/sys/pccard/pccard.c
@@ -366,8 +366,9 @@ allocate_driver(struct slot *slt, struct dev_desc *desc)
 	bcopy(desc->misc, devi->misc, sizeof(desc->misc));
 	resource_list_init(&devi->resources);
 	child = devi->isahd.id_device = device_add_child(pccarddev, devi->name,
-	    desc->unit, devi);
+	    desc->unit);
 	device_set_flags(child, desc->flags);
+	device_set_ivars(child, devi);
 	err = bus_set_resource(child, SYS_RES_IOPORT, 0, desc->iobase,
 	    desc->iosize);
 	if (err)
diff --git a/sys/pccard/pcic.c b/sys/pccard/pcic.c
index 530601d..f4514a5 100644
--- a/sys/pccard/pcic.c
+++ b/sys/pccard/pcic.c
@@ -512,7 +512,7 @@ pcic_probe(device_t dev)
 		pcictimeout_ch = timeout(pcictimeout, 0, hz/2);
 	if (validslots) {
 		for (i = 0; i < validslots; i++) {
-			device_add_child(dev, NULL, -1, NULL);
+			device_add_child(dev, NULL, -1);
 		}
 	}
 	return(validslots ? 0 : ENXIO);
diff --git a/sys/pci/alpm.c b/sys/pci/alpm.c
index ff4c5d3..358a032 100644
--- a/sys/pci/alpm.c
+++ b/sys/pci/alpm.c
@@ -281,7 +281,7 @@ alpm_pci_attach(pcici_t tag, int unit)
 		printf(" at 0x%x\n", alpm->smbsh);
 
 	/* XXX add the I2C interface to the root_bus until pcibus is ready */
-	device_add_child(root_bus, "alsmb", unit, NULL);
+	device_add_child(root_bus, "alsmb", unit);
 
 	return;
 }
diff --git a/sys/pci/intpm.c b/sys/pci/intpm.c
index 4e3acd7..fccd0c3 100644
--- a/sys/pci/intpm.c
+++ b/sys/pci/intpm.c
@@ -711,7 +711,7 @@ intpm_attach(device_t dev)
                         device_printf(dev,"Failed to map intr\n");
 			return error;
                 }
-                smbinterface=device_add_child(dev,"intsmb",unit,NULL);
+                smbinterface=device_add_child(dev,"intsmb",unit);
 		if(!smbinterface){
 		     printf("intsmb%d:could not add SMBus device\n",unit);
 		}
diff --git a/sys/pci/ohci_pci.c b/sys/pci/ohci_pci.c
index 8e1378b..f8c4964 100644
--- a/sys/pci/ohci_pci.c
+++ b/sys/pci/ohci_pci.c
@@ -168,7 +168,8 @@ ohci_pci_attach(device_t self)
 		return ENOMEM;
 	}
 
-	usbus = device_add_child(self, "usb", -1, sc);
+	usbus = device_add_child(self, "usb", -1);
+	device_set_ivars(usbus, sc);
 	if (!usbus) {
 		device_printf(self, "could not add USB device\n");
 		return ENOMEM;
diff --git a/sys/pci/pci.c b/sys/pci/pci.c
index efb98d2..b4dd70b 100644
--- a/sys/pci/pci.c
+++ b/sys/pci/pci.c
@@ -1115,8 +1115,8 @@ pci_add_children(device_t dev, int busno)
 					pcifunchigh = 7;
 
 				pci_print_verbose(dinfo);
-				dinfo->cfg.dev =
-					device_add_child(dev, NULL, -1, dinfo);
+				dinfo->cfg.dev = device_add_child(dev, NULL, -1);
+				device_set_ivars(dinfo->cfg.dev, dinfo);
 				pci_add_resources(dinfo->cfg.dev, &dinfo->cfg);
 			}
 		}
diff --git a/sys/pci/pcisupport.c b/sys/pci/pcisupport.c
index 6dcaa09..519c63b 100644
--- a/sys/pci/pcisupport.c
+++ b/sys/pci/pcisupport.c
@@ -779,7 +779,7 @@ static int pcib_attach(device_t dev)
 
 	secondary = pci_get_secondarybus(dev);
 	if (secondary) {
-		device_add_child(dev, "pci", secondary, 0);
+		device_add_child(dev, "pci", secondary);
 		return bus_generic_attach(dev);
 	} else
 		return 0;
@@ -926,10 +926,10 @@ isab_probe(device_t dev)
 		 */
 		device_set_desc_copy(dev, desc);
 		if (is_eisa && !devclass_get_device(devclass_find("eisa"), 0))
-			device_add_child(dev, "eisa", -1, 0);
+			device_add_child(dev, "eisa", -1);
 
 		if (!devclass_get_device(devclass_find("isa"), 0))
-			device_add_child(dev, "isa", -1, 0);
+			device_add_child(dev, "isa", -1);
 		return 0;
 	}
 	return ENXIO;
diff --git a/sys/pci/uhci_pci.c b/sys/pci/uhci_pci.c
index 9285174..0857f16 100644
--- a/sys/pci/uhci_pci.c
+++ b/sys/pci/uhci_pci.c
@@ -181,7 +181,8 @@ uhci_pci_attach(device_t self)
 		return ENOMEM;
 	}
 		
-	usbus = device_add_child(self, "usb", -1, sc);
+	usbus = device_add_child(self, "usb", -1);
+	device_set_ivars(usbus, sc);
 	if (!usbus) {
 		device_printf(self, "could not add USB device\n");
 		return ENOMEM;
diff --git a/sys/sys/bus.h b/sys/sys/bus.h
index 5c32be7..a3cea15 100644
--- a/sys/sys/bus.h
+++ b/sys/sys/bus.h
@@ -222,11 +222,9 @@ void	bus_delete_resource(device_t dev, int type, int rid);
 /*
  * Access functions for device.
  */
-device_t	device_add_child(device_t dev, const char *name, int unit,
-				 void *ivp);
+device_t	device_add_child(device_t dev, const char *name, int unit);
 device_t	device_add_child_ordered(device_t dev, int order,
-					 const char *name, int unit,
-					 void *ivp);
+					 const char *name, int unit);
 void	device_busy(device_t dev);
 int	device_delete_child(device_t dev, device_t child);
 int	device_detach(device_t dev);
@@ -241,6 +239,7 @@ u_int32_t	device_get_flags(device_t dev);
 device_t	device_get_parent(device_t dev);
 int	device_get_children(device_t dev, device_t **listp, int *countp);
 void	*device_get_ivars(device_t dev);
+void	device_set_ivars(device_t dev, void *ivars);
 const	char *device_get_name(device_t dev);
 const	char *device_get_nameunit(device_t dev);
 void	*device_get_softc(device_t dev);