diff --git a/sys/dev/adb/adb_kbd.c b/sys/dev/adb/adb_kbd.c
index 2fe760932039..cd2a9a7b7635 100644
--- a/sys/dev/adb/adb_kbd.c
+++ b/sys/dev/adb/adb_kbd.c
@@ -162,7 +162,7 @@ keycode2scancode(int keycode, int shift, int up)
 	int scancode;
 
 	scancode = keycode;
-	if ((keycode >= 89) && (keycode < 89 + sizeof(scan) / sizeof(scan[0])))
+	if ((keycode >= 89) && (keycode < 89 + nitems(scan)))
 	scancode = scan[keycode - 89] | SCAN_PREFIX_E0;
 	/* pause/break */
 	if ((keycode == 104) && !(shift & CTLS))
diff --git a/sys/dev/age/if_age.c b/sys/dev/age/if_age.c
index 9e2fec80b0ad..8ed176eec768 100644
--- a/sys/dev/age/if_age.c
+++ b/sys/dev/age/if_age.c
@@ -323,8 +323,7 @@ age_probe(device_t dev)
 	vendor = pci_get_vendor(dev);
 	devid = pci_get_device(dev);
 	sp = age_devs;
-	for (i = 0; i < sizeof(age_devs) / sizeof(age_devs[0]);
-	    i++, sp++) {
+	for (i = 0; i < nitems(age_devs); i++, sp++) {
 		if (vendor == sp->age_vendorid &&
 		    devid == sp->age_deviceid) {
 			device_set_desc(dev, sp->age_name);
diff --git a/sys/dev/aha/aha_isa.c b/sys/dev/aha/aha_isa.c
index c4e7ba90db0b..db6fa0c3fc3b 100644
--- a/sys/dev/aha/aha_isa.c
+++ b/sys/dev/aha/aha_isa.c
@@ -310,8 +310,7 @@ aha_isa_identify(driver_t *driver, device_t parent)
 	device_t child;
 
 	/* Attempt to find an adapter */
-	for (i = 0; i < sizeof(aha_board_ports) / sizeof(aha_board_ports[0]);
-	    i++) {
+	for (i = 0; i < nitems(aha_board_ports); i++) {
 		bzero(&aha, sizeof(aha));
 		ioport = aha_board_ports[i];
 		/*
diff --git a/sys/dev/ale/if_ale.c b/sys/dev/ale/if_ale.c
index e4db2fa4ab62..e7d030636cab 100644
--- a/sys/dev/ale/if_ale.c
+++ b/sys/dev/ale/if_ale.c
@@ -343,7 +343,7 @@ ale_probe(device_t dev)
 	vendor = pci_get_vendor(dev);
 	devid = pci_get_device(dev);
 	sp = ale_devs;
-	for (i = 0; i < sizeof(ale_devs) / sizeof(ale_devs[0]); i++) {
+	for (i = 0; i < nitems(ale_devs); i++) {
 		if (vendor == sp->ale_vendorid &&
 		    devid == sp->ale_deviceid) {
 			device_set_desc(dev, sp->ale_name);
diff --git a/sys/dev/altera/atse/if_atse.c b/sys/dev/altera/atse/if_atse.c
index 1c55fbc9666b..5e37ad294030 100644
--- a/sys/dev/altera/atse/if_atse.c
+++ b/sys/dev/altera/atse/if_atse.c
@@ -1727,8 +1727,7 @@ atse_sysctl_stats_attach(device_t dev)
         soid = device_get_sysctl_tree(dev);
 
 	/* MAC statistics. */
-	for (i = 0; i < sizeof(atse_mac_stats_regs) /
-	    sizeof(*atse_mac_stats_regs); i++) {
+	for (i = 0; i < nitems(atse_mac_stats_regs); i++) {
 		if (atse_mac_stats_regs[i].name == NULL ||
 		    atse_mac_stats_regs[i].descr == NULL)
 			continue;
diff --git a/sys/dev/atkbdc/atkbd.c b/sys/dev/atkbdc/atkbd.c
index a90f5d203db7..8fba5788db90 100644
--- a/sys/dev/atkbdc/atkbd.c
+++ b/sys/dev/atkbdc/atkbd.c
@@ -362,8 +362,7 @@ atkbd_init(int unit, keyboard_t **kbdp, void *arg, int flags)
 		keymap = &default_keymap;
 		accmap = &default_accentmap;
 		fkeymap = default_fkeytab;
-		fkeymap_size =
-			sizeof(default_fkeytab)/sizeof(default_fkeytab[0]);
+		fkeymap_size = nitems(default_fkeytab);
 		needfree = 0;
 	} else if (*kbdp == NULL) {
 		*kbdp = kbd = malloc(sizeof(*kbd), M_DEVBUF, M_NOWAIT | M_ZERO);
@@ -1506,12 +1505,12 @@ typematic(int delay, int rate)
 	int value;
 	int i;
 
-	for (i = sizeof(delays)/sizeof(delays[0]) - 1; i > 0; --i) {
+	for (i = nitems(delays) - 1; i > 0; --i) {
 		if (delay >= delays[i])
 			break;
 	}
 	value = i << 5;
-	for (i = sizeof(rates)/sizeof(rates[0]) - 1; i > 0; --i) {
+	for (i = nitems(rates) - 1; i > 0; --i) {
 		if (rate >= rates[i])
 			break;
 	}
diff --git a/sys/dev/atkbdc/atkbdc.c b/sys/dev/atkbdc/atkbdc.c
index 69ffa63f338e..695e6bfd84ab 100644
--- a/sys/dev/atkbdc/atkbdc.c
+++ b/sys/dev/atkbdc/atkbdc.c
@@ -154,7 +154,7 @@ atkbdc_softc_t
 {
 	atkbdc_softc_t *sc;
 
-	if (unit >= sizeof(atkbdc_softc)/sizeof(atkbdc_softc[0]))
+	if (unit >= nitems(atkbdc_softc))
 		return NULL;
 	sc = atkbdc_softc[unit];
 	if (sc == NULL) {
diff --git a/sys/dev/atkbdc/psm.c b/sys/dev/atkbdc/psm.c
index 0103baf6f56b..b5c4856a4b8e 100644
--- a/sys/dev/atkbdc/psm.c
+++ b/sys/dev/atkbdc/psm.c
@@ -524,8 +524,7 @@ static struct {
 	{ MOUSE_MODEL_GENERIC,
 	  0xc0, MOUSE_PS2_PACKETSIZE, NULL },
 };
-#define	GENERIC_MOUSE_ENTRY	\
-    ((sizeof(vendortype) / sizeof(*vendortype)) - 1)
+#define	GENERIC_MOUSE_ENTRY (nitems(vendortype) - 1)
 
 /* device driver declarateion */
 static device_method_t psm_methods[] = {
@@ -3874,7 +3873,7 @@ enable_kmouse(struct psm_softc *sc, enum probearg arg)
 	 * The special sequence to enable the third and fourth buttons.
 	 * Otherwise they behave like the first and second buttons.
 	 */
-	for (i = 0; i < sizeof(rate)/sizeof(rate[0]); ++i)
+	for (i = 0; i < nitems(rate); ++i)
 		if (set_mouse_sampling_rate(kbdc, rate[i]) != rate[i])
 			return (FALSE);
 
@@ -3971,7 +3970,7 @@ enable_msexplorer(struct psm_softc *sc, enum probearg arg)
 	enable_msintelli(sc, arg);
 
 	/* the special sequence to enable the extra buttons and the roller. */
-	for (i = 0; i < sizeof(rate1)/sizeof(rate1[0]); ++i)
+	for (i = 0; i < nitems(rate1); ++i)
 		if (set_mouse_sampling_rate(kbdc, rate1[i]) != rate1[i])
 			return (FALSE);
 	/* the device will give the genuine ID only after the above sequence */
@@ -3994,7 +3993,7 @@ enable_msexplorer(struct psm_softc *sc, enum probearg arg)
 	 * sequence; it will make the KVM think the mouse is IntelliMouse
 	 * when it is in fact IntelliMouse Explorer.
 	 */
-	for (i = 0; i < sizeof(rate0)/sizeof(rate0[0]); ++i)
+	for (i = 0; i < nitems(rate0); ++i)
 		if (set_mouse_sampling_rate(kbdc, rate0[i]) != rate0[i])
 			break;
 	get_aux_id(kbdc);
@@ -4016,7 +4015,7 @@ enable_msintelli(struct psm_softc *sc, enum probearg arg)
 	int i;
 
 	/* the special sequence to enable the third button and the roller. */
-	for (i = 0; i < sizeof(rate)/sizeof(rate[0]); ++i)
+	for (i = 0; i < nitems(rate); ++i)
 		if (set_mouse_sampling_rate(kbdc, rate[i]) != rate[i])
 			return (FALSE);
 	/* the device will give the genuine ID only after the above sequence */
@@ -4044,7 +4043,7 @@ enable_4dmouse(struct psm_softc *sc, enum probearg arg)
 	int id;
 	int i;
 
-	for (i = 0; i < sizeof(rate)/sizeof(rate[0]); ++i)
+	for (i = 0; i < nitems(rate); ++i)
 		if (set_mouse_sampling_rate(kbdc, rate[i]) != rate[i])
 			return (FALSE);
 	id = get_aux_id(kbdc);
diff --git a/sys/dev/bktr/bktr_core.c b/sys/dev/bktr/bktr_core.c
index 764eda563c73..67f3ab1896f0 100644
--- a/sys/dev/bktr/bktr_core.c
+++ b/sys/dev/bktr/bktr_core.c
@@ -324,7 +324,7 @@ static struct meteor_pixfmt_internal {
 { { 0, METEOR_PIXTYPE_YUV_12, 2, { 0xff0000,0x00ff00,0x0000ff }, 1,1 }, 0x88 },
 
 };
-#define PIXFMT_TABLE_SIZE ( sizeof(pixfmt_table) / sizeof(pixfmt_table[0]) )
+#define	PIXFMT_TABLE_SIZE nitems(pixfmt_table)
 
 /*
  * Table of Meteor-supported Pixel Formats (for SETGEO compatibility)
@@ -354,8 +354,7 @@ static struct {
     },
 
 };
-#define METEOR_PIXFMT_TABLE_SIZE ( sizeof(meteor_pixfmt_table) / \
-				   sizeof(meteor_pixfmt_table[0]) )
+#define	METEOR_PIXFMT_TABLE_SIZE nitems(meteor_pixfmt_table)
 
 
 #define BSWAP (BT848_COLOR_CTL_BSWAP_ODD | BT848_COLOR_CTL_BSWAP_EVEN)
diff --git a/sys/dev/bwi/bwirf.c b/sys/dev/bwi/bwirf.c
index 341e929f6a5f..e65a80ddc412 100644
--- a/sys/dev/bwi/bwirf.c
+++ b/sys/dev/bwi/bwirf.c
@@ -1018,8 +1018,7 @@ bwi_rf_calibval(struct bwi_mac *mac)
 
 	val = RF_READ(mac, BWI_RFR_BBP_ATTEN);
 	idx = __SHIFTOUT(val, BWI_RFR_BBP_ATTEN_CALIB_IDX);
-	KASSERT(idx < (int)(sizeof(rf_calibvals) / sizeof(rf_calibvals[0])),
-	    ("idx %d", idx));
+	KASSERT(idx < (int)nitems(rf_calibvals), ("idx %d", idx));
 
 	calib = rf_calibvals[idx] << 1;
 	if (val & BWI_RFR_BBP_ATTEN_CALIB_BIT)
diff --git a/sys/dev/bwn/if_bwn.c b/sys/dev/bwn/if_bwn.c
index decef5fcc23a..a7b04800fcfd 100644
--- a/sys/dev/bwn/if_bwn.c
+++ b/sys/dev/bwn/if_bwn.c
@@ -906,7 +906,7 @@ bwn_probe(device_t dev)
 {
 	int i;
 
-	for (i = 0; i < sizeof(bwn_devs) / sizeof(bwn_devs[0]); i++) {
+	for (i = 0; i < nitems(bwn_devs); i++) {
 		if (siba_get_vendor(dev) == bwn_devs[i].sd_vendor &&
 		    siba_get_device(dev) == bwn_devs[i].sd_device &&
 		    siba_get_revid(dev) == bwn_devs[i].sd_rev)
diff --git a/sys/dev/cardbus/cardbus_cis.c b/sys/dev/cardbus/cardbus_cis.c
index f9f7816e4c4b..00c34a6d9e84 100644
--- a/sys/dev/cardbus/cardbus_cis.c
+++ b/sys/dev/cardbus/cardbus_cis.c
@@ -205,7 +205,7 @@ decode_tuple_funcid(device_t cbdev, device_t child, int id,
     struct tuple_callbacks *info, void *argp)
 {
 	struct cardbus_devinfo *dinfo = device_get_ivars(child);
-	int numnames = sizeof(funcnames) / sizeof(funcnames[0]);
+	int numnames = nitems(funcnames);
 	int i;
 
 	if (cardbus_cis_debug) {
diff --git a/sys/dev/digi/digi.c b/sys/dev/digi/digi.c
index 7adc72a398d1..b8ede24a871a 100644
--- a/sys/dev/digi/digi.c
+++ b/sys/dev/digi/digi.c
@@ -1441,8 +1441,8 @@ digi_errortxt(int id)
 		"tty-level buffer overflow",
 	};
 
-	KASSERT(id >= 0 && id < sizeof(error_desc) / sizeof(error_desc[0]),
-	    ("Unexpected digi error id %d\n", id));
+	KASSERT(id >= 0 && id < nitems(error_desc),
+		("Unexpected digi error id %d\n", id));
 
 	return (error_desc[id]);
 }
diff --git a/sys/dev/digi/digi_isa.c b/sys/dev/digi/digi_isa.c
index 647ea1d8bc56..d549110aae0e 100644
--- a/sys/dev/digi/digi_isa.c
+++ b/sys/dev/digi/digi_isa.c
@@ -58,7 +58,7 @@ __FBSDID("$FreeBSD$");
 static u_long digi_validio[] = {
 	0x100, 0x110, 0x120, 0x200, 0x220, 0x300, 0x320
 };
-#define DIGI_NVALIDIO	(sizeof(digi_validio) / sizeof(digi_validio[0]))
+#define	DIGI_NVALIDIO	nitems(digi_validio)
 #define	IO_SIZE		0x04
 
 static u_long digi_validmem[] = {
@@ -68,7 +68,7 @@ static u_long digi_validmem[] = {
 	0xf6000000, 0xf7000000, 0xf8000000, 0xf9000000, 0xfa000000, 0xfb000000,
 	0xfc000000, 0xfd000000, 0xfe000000, 0xff000000
 };
-#define DIGI_NVALIDMEM	(sizeof(digi_validmem) / sizeof(digi_validmem[0]))
+#define	DIGI_NVALIDMEM	(nitems(digi_validmem))
 
 static u_char *
 digi_isa_setwin(struct digi_softc *sc, unsigned int addr)
diff --git a/sys/dev/dwc/if_dwc.c b/sys/dev/dwc/if_dwc.c
index 1984c48f1402..988516e5f4fc 100644
--- a/sys/dev/dwc/if_dwc.c
+++ b/sys/dev/dwc/if_dwc.c
@@ -1049,7 +1049,7 @@ dwc_reset(device_t dev)
 	}
 
 	if (GPIO_MAP_GPIOS(gpio, node, gpio_node,
-	    sizeof(gpio_prop) / sizeof(gpio_prop[0]) - 1,
+	    nitems(gpio_prop) - 1,
 	    gpio_prop + 1, &pin, &flags) != 0) {
 		device_printf(dev, "Can't map gpio for phy reset\n");
 		return (ENXIO);
diff --git a/sys/dev/ed/if_ed_hpp.c b/sys/dev/ed/if_ed_hpp.c
index ec5c8db268bd..85df356b617c 100644
--- a/sys/dev/ed/if_ed_hpp.c
+++ b/sys/dev/ed/if_ed_hpp.c
@@ -214,7 +214,7 @@ ed_probe_HP_pclanp(device_t dev, int port_rid, int flags)
  	 * Check for impossible IRQ.
 	 */
 
-	if (irq >= (sizeof(ed_hpp_intr_val) / sizeof(ed_hpp_intr_val[0])))
+	if (irq >= (nitems(ed_hpp_intr_val)))
 		return (ENXIO);
 
 	/* 
diff --git a/sys/dev/ed/if_ed_isa.c b/sys/dev/ed/if_ed_isa.c
index 7b1a6b7c755a..7b974dc27f63 100644
--- a/sys/dev/ed/if_ed_isa.c
+++ b/sys/dev/ed/if_ed_isa.c
@@ -202,5 +202,5 @@ DRIVER_MODULE(ed, isa, ed_isa_driver, ed_devclass, 0, 0);
 MODULE_DEPEND(ed, isa, 1, 1, 1);
 MODULE_DEPEND(ed, ether, 1, 1, 1);
 MODULE_PNP_INFO("E:pnpid;", isa, ed, ed_ids, sizeof(ed_ids[0]),
-    sizeof(ed_ids) / sizeof(ed_ids[0]) - 1);
+    nitems(ed_ids) - 1);
 
diff --git a/sys/dev/ed/if_ed_pci.c b/sys/dev/ed/if_ed_pci.c
index 31b9762f729c..04130df2298f 100644
--- a/sys/dev/ed/if_ed_pci.c
+++ b/sys/dev/ed/if_ed_pci.c
@@ -144,5 +144,5 @@ DRIVER_MODULE(ed, pci, ed_pci_driver, ed_devclass, 0, 0);
 MODULE_DEPEND(ed, pci, 1, 1, 1);
 MODULE_DEPEND(ed, ether, 1, 1, 1);
 MODULE_PNP_INFO("W32:vendor/device;D:human", pci, ed, pci_ids, sizeof(pci_ids[0]),
-    sizeof(pci_ids) / sizeof(pci_ids[0]) - 1);
+    nitems(pci_ids) - 1);
 
diff --git a/sys/dev/flash/mx25l.c b/sys/dev/flash/mx25l.c
index 645fb36f27a7..9b5b9aa78649 100644
--- a/sys/dev/flash/mx25l.c
+++ b/sys/dev/flash/mx25l.c
@@ -189,7 +189,7 @@ mx25l_get_device_ident(struct mx25l_softc *sc)
 	dev_id = (rxBuf[2] << 8) | (rxBuf[3]);
 
 	for (i = 0; 
-	    i < sizeof(flash_devices)/sizeof(struct mx25l_flash_ident); i++) {
+	    i < nitems(flash_devices); i++) {
 		if ((flash_devices[i].manufacturer_id == manufacturer_id) &&
 		    (flash_devices[i].device_id == dev_id))
 			return &flash_devices[i];
diff --git a/sys/dev/hatm/if_hatm.c b/sys/dev/hatm/if_hatm.c
index 0677a149aace..d1dd6b1dad28 100644
--- a/sys/dev/hatm/if_hatm.c
+++ b/sys/dev/hatm/if_hatm.c
@@ -608,7 +608,7 @@ hatm_read_prom_byte(struct hatm_softc *sc, u_int addr)
 	BARRIER_W(sc);
 
 	/* send READ */
-	for (i = 0; i < sizeof(readtab) / sizeof(readtab[0]); i++) {
+	for (i = 0; i < nitems(readtab); i++) {
 		WRITE4(sc, HE_REGO_HOST_CNTL, val | readtab[i]);
 		BARRIER_W(sc);
 		DELAY(EEPROM_DELAY);
diff --git a/sys/dev/hifn/hifn7751.c b/sys/dev/hifn/hifn7751.c
index ba510be5b5bf..65dbfab955ab 100644
--- a/sys/dev/hifn/hifn7751.c
+++ b/sys/dev/hifn/hifn7751.c
@@ -1029,7 +1029,7 @@ hifn_enable_crypto(struct hifn_softc *sc)
 	u_int32_t dmacfg, ramcfg, encl, addr, i;
 	char *offtbl = NULL;
 
-	for (i = 0; i < sizeof(pci2id)/sizeof(pci2id[0]); i++) {
+	for (i = 0; i < nitems(pci2id); i++) {
 		if (pci2id[i].pci_vendor == pci_get_vendor(sc->sc_dev) &&
 		    pci2id[i].pci_prod == pci_get_device(sc->sc_dev)) {
 			offtbl = pci2id[i].card_id;
diff --git a/sys/dev/if_ndis/if_ndis.c b/sys/dev/if_ndis/if_ndis.c
index 47594fc60224..50842028f650 100644
--- a/sys/dev/if_ndis/if_ndis.c
+++ b/sys/dev/if_ndis/if_ndis.c
@@ -2400,7 +2400,7 @@ ndis_setstate_80211(struct ndis_softc *sc)
 
 	/* Set TX power */
 	if ((ic->ic_caps & IEEE80211_C_TXPMGT) &&
-	    ic->ic_txpowlimit < (sizeof(dBm2mW) / sizeof(dBm2mW[0]))) {
+	    ic->ic_txpowlimit < nitems(dBm2mW)) {
 		arg = dBm2mW[ic->ic_txpowlimit];
 		len = sizeof(arg);
 		ndis_set_info(sc, OID_802_11_TX_POWER_LEVEL, &arg, &len);
@@ -2810,7 +2810,7 @@ ndis_getstate_80211(struct ndis_softc *sc)
 	if (ic->ic_caps & IEEE80211_C_TXPMGT) {
 		len = sizeof(arg);
 		ndis_get_info(sc, OID_802_11_TX_POWER_LEVEL, &arg, &len);
-		for (i = 0; i < (sizeof(dBm2mW) / sizeof(dBm2mW[0])); i++)
+		for (i = 0; i < nitems(dBm2mW); i++)
 			if (dBm2mW[i] >= arg)
 				break;
 		ic->ic_txpowlimit = i;
diff --git a/sys/dev/jme/if_jme.c b/sys/dev/jme/if_jme.c
index d3a1057b0303..f2567ccf0ee3 100644
--- a/sys/dev/jme/if_jme.c
+++ b/sys/dev/jme/if_jme.c
@@ -337,8 +337,7 @@ jme_probe(device_t dev)
 	vendor = pci_get_vendor(dev);
 	devid = pci_get_device(dev);
 	sp = jme_devs;
-	for (i = 0; i < sizeof(jme_devs) / sizeof(jme_devs[0]);
-	    i++, sp++) {
+	for (i = 0; i < nitems(jme_devs); i++, sp++) {
 		if (vendor == sp->jme_vendorid &&
 		    devid == sp->jme_deviceid) {
 			device_set_desc(dev, sp->jme_name);
diff --git a/sys/dev/kbd/kbd.c b/sys/dev/kbd/kbd.c
index 803676288882..45f483ac1a23 100644
--- a/sys/dev/kbd/kbd.c
+++ b/sys/dev/kbd/kbd.c
@@ -1144,7 +1144,7 @@ static char
 	};
 	int i;
 
-	for (i = 0; i < sizeof(name_table)/sizeof(name_table[0]); ++i) {
+	for (i = 0; i < nitems(name_table); ++i) {
 		if (type == name_table[i].type)
 			return (name_table[i].name);
 	}
diff --git a/sys/dev/mlx/mlx.c b/sys/dev/mlx/mlx.c
index 58eb71ba8d37..6d9c49b925f2 100644
--- a/sys/dev/mlx/mlx.c
+++ b/sys/dev/mlx/mlx.c
@@ -1364,7 +1364,7 @@ mlx_periodic_eventlog_respond(struct mlx_command *mc)
 	    /* Mylex vendor-specific message indicating a drive was killed? */
 	    if ((el->el_sensekey == 9) &&
 		(el->el_asc == 0x80)) {
-		if (el->el_asq < (sizeof(mlx_sense_messages) / sizeof(mlx_sense_messages[0]))) {
+		if (el->el_asq < nitems(mlx_sense_messages)) {
 		    reason = mlx_sense_messages[el->el_asq];
 		} else {
 		    reason = "for unknown reason";
diff --git a/sys/dev/mxge/if_mxge.c b/sys/dev/mxge/if_mxge.c
index f78b34b2a233..8da11d70f9d1 100644
--- a/sys/dev/mxge/if_mxge.c
+++ b/sys/dev/mxge/if_mxge.c
@@ -2994,16 +2994,14 @@ mxge_media_probe(mxge_softc_t *sc)
 		/* -R is XFP */
 		mxge_media_types = mxge_xfp_media_types;
 		mxge_media_type_entries =
-			sizeof (mxge_xfp_media_types) /
-			sizeof (mxge_xfp_media_types[0]);
+			nitems(mxge_xfp_media_types);
 		byte = MXGE_XFP_COMPLIANCE_BYTE;
 		cage_type = "XFP";
 	} else 	if (sc->connector == MXGE_SFP) {
 		/* -S or -2S is SFP+ */
 		mxge_media_types = mxge_sfp_media_types;
 		mxge_media_type_entries =
-			sizeof (mxge_sfp_media_types) /
-			sizeof (mxge_sfp_media_types[0]);
+			nitems(mxge_sfp_media_types);
 		cage_type = "SFP+";
 		byte = 3;
 	} else {
diff --git a/sys/dev/nand/nand_id.c b/sys/dev/nand/nand_id.c
index 621e9818edd9..bf0b44a158db 100644
--- a/sys/dev/nand/nand_id.c
+++ b/sys/dev/nand/nand_id.c
@@ -59,7 +59,7 @@ struct nand_params *nand_get_params(struct nand_id *id)
 {
 	int i;
 
-	for (i = 0; i < sizeof(nand_ids) / sizeof(nand_ids[0]); i++)
+	for (i = 0; i < nitems(nand_ids); i++)
 		if (nand_ids[i].id.man_id == id->man_id &&
 		    nand_ids[i].id.dev_id == id->dev_id)
 			return (&nand_ids[i]);
diff --git a/sys/dev/ncr/ncr.c b/sys/dev/ncr/ncr.c
index 8cf142f5fb23..7a1c1d2bd2b8 100644
--- a/sys/dev/ncr/ncr.c
+++ b/sys/dev/ncr/ncr.c
@@ -3230,7 +3230,7 @@ static int ncr_chip_lookup(u_long device_id, u_char revision_id)
 	int i, found;
 	
 	found = -1;
-	for (i = 0; i < sizeof(ncr_chip_table)/sizeof(ncr_chip_table[0]); i++) {
+	for (i = 0; i < nitems(ncr_chip_table); i++) {
 		if (device_id	== ncr_chip_table[i].device_id &&
 		    ncr_chip_table[i].minrevid <= revision_id) {
 			if (found < 0 || 
diff --git a/sys/dev/nctgpio/nctgpio.c b/sys/dev/nctgpio/nctgpio.c
index ab547c0b40de..ac2ac574108f 100644
--- a/sys/dev/nctgpio/nctgpio.c
+++ b/sys/dev/nctgpio/nctgpio.c
@@ -455,7 +455,7 @@ nct_probe(device_t dev)
 
 	sc = device_get_softc(dev);
 
-	for (i = 0; i < sizeof(probe_addrs) / sizeof(*probe_addrs); i++) {
+	for (i = 0; i < nitems(probe_addrs); i++) {
 		sc->rid = 0;
 		sc->portres = bus_alloc_resource(dev, SYS_RES_IOPORT, &sc->rid,
 			probe_addrs[i], probe_addrs[i] + 1, 2, RF_ACTIVE);
@@ -476,7 +476,7 @@ nct_probe(device_t dev)
 		bus_release_resource(dev, SYS_RES_IOPORT, sc->rid, sc->portres);
 		bus_delete_resource(dev, SYS_RES_IOPORT, sc->rid);
 
-		for (j = 0; j < sizeof(nct_devs) / sizeof(*nct_devs); j++) {
+		for (j = 0; j < nitems(nct_devs); j++) {
 			if (chipid == nct_devs[j].chip_id) {
 				rc = bus_set_resource(dev, SYS_RES_IOPORT, 0, probe_addrs[i], 2);
 				if (rc != 0) {
diff --git a/sys/dev/nfe/if_nfe.c b/sys/dev/nfe/if_nfe.c
index 58fee0b9feca..d3accc57bd87 100644
--- a/sys/dev/nfe/if_nfe.c
+++ b/sys/dev/nfe/if_nfe.c
@@ -843,7 +843,7 @@ nfe_can_use_msix(struct nfe_softc *sc)
 	product = kern_getenv("smbios.planar.product");
 	use_msix = 1;
 	if (maker != NULL && product != NULL) {
-		count = sizeof(msix_blacklists) / sizeof(msix_blacklists[0]);
+		count = nitems(msix_blacklists);
 		mblp = msix_blacklists;
 		for (n = 0; n < count; n++) {
 			if (strcmp(maker, mblp->maker) == 0 &&
diff --git a/sys/dev/patm/if_patm_attach.c b/sys/dev/patm/if_patm_attach.c
index 29a2a87bd308..8d936bbeb374 100644
--- a/sys/dev/patm/if_patm_attach.c
+++ b/sys/dev/patm/if_patm_attach.c
@@ -675,7 +675,7 @@ patm_read_eeprom(struct patm_softc *sc)
 	gp = patm_nor_read(sc, IDT_NOR_GP);
 	gp &= ~(IDT_GP_EESCLK | IDT_GP_EECS | IDT_GP_EEDO);
 
-	for (i = 0; i < sizeof(tab) / sizeof(tab[0]); i++) {
+	for (i = 0; i < nitems(tab); i++) {
 		patm_nor_write(sc, IDT_NOR_GP, gp | tab[i]);
 		DELAY(40);
 	}
diff --git a/sys/dev/rc/rc.c b/sys/dev/rc/rc.c
index 1e8a23a8cfda..d600626ba9a6 100644
--- a/sys/dev/rc/rc.c
+++ b/sys/dev/rc/rc.c
@@ -186,7 +186,7 @@ rc_probe(device_t dev)
 	if (port == -1)
 		return (ENXIO);
 	found = 0;
-	for (i = 0; i < sizeof(rc_ports) / sizeof(int); i++)
+	for (i = 0; i < nitems(rc_ports); i++)
 		if (rc_ports[i] == port) {
 			found = 1;
 			break;
diff --git a/sys/dev/re/if_re.c b/sys/dev/re/if_re.c
index 90bdffd1d10a..a5bc3be03999 100644
--- a/sys/dev/re/if_re.c
+++ b/sys/dev/re/if_re.c
@@ -953,7 +953,7 @@ re_probe(device_t dev)
 	}
 
 	t = re_devs;
-	for (i = 0; i < sizeof(re_devs) / sizeof(re_devs[0]); i++, t++) {
+	for (i = 0; i < nitems(re_devs); i++, t++) {
 		if (vendor == t->rl_vid && devid == t->rl_did) {
 			device_set_desc(dev, t->rl_name);
 			return (BUS_PROBE_DEFAULT);
diff --git a/sys/dev/rl/if_rl.c b/sys/dev/rl/if_rl.c
index d9b79396b7c4..356da24f2e1e 100644
--- a/sys/dev/rl/if_rl.c
+++ b/sys/dev/rl/if_rl.c
@@ -598,7 +598,7 @@ rl_probe(device_t dev)
 		}
 	}
 	t = rl_devs;
-	for (i = 0; i < sizeof(rl_devs) / sizeof(rl_devs[0]); i++, t++) {
+	for (i = 0; i < nitems(rl_devs); i++, t++) {
 		if (vendor == t->rl_vid && devid == t->rl_did) {
 			device_set_desc(dev, t->rl_name);
 			return (BUS_PROBE_DEFAULT);
diff --git a/sys/dev/sf/if_sf.c b/sys/dev/sf/if_sf.c
index d2c43945233b..bd685f132a3f 100644
--- a/sys/dev/sf/if_sf.c
+++ b/sys/dev/sf/if_sf.c
@@ -710,7 +710,7 @@ sf_probe(device_t dev)
 	sdid = pci_get_subdevice(dev);
 
 	t = sf_devs;
-	for (i = 0; i < sizeof(sf_devs) / sizeof(sf_devs[0]); i++, t++) {
+	for (i = 0; i < nitems(sf_devs); i++, t++) {
 		if (vid == t->sf_vid && did == t->sf_did) {
 			if (sdid == t->sf_sdid) {
 				device_set_desc(dev, t->sf_sname);
diff --git a/sys/dev/sio/sio.c b/sys/dev/sio/sio.c
index c27b7bcb3f19..60ba8b85c4b4 100644
--- a/sys/dev/sio/sio.c
+++ b/sys/dev/sio/sio.c
@@ -1638,7 +1638,7 @@ if (com->iptr - com->ibuf == 8)
 				outb(com->data_port, *ioptr++);
 				++com->bytes_out;
 				if (com->unit == siotsunit
-				    && siotso < sizeof siots / sizeof siots[0])
+				    && siotso < nitems(siots))
 					nanouptime(&siots[siotso++]);
 			}
 			com->obufq.l_head = ioptr;
diff --git a/sys/dev/sound/isa/gusc.c b/sys/dev/sound/isa/gusc.c
index bcb5957ab055..239fd042223a 100644
--- a/sys/dev/sound/isa/gusc.c
+++ b/sys/dev/sound/isa/gusc.c
@@ -491,7 +491,7 @@ alloc_resource(sc_p scp)
 			base = isa_get_port(scp->dev);
 		else
 			base = 0;
-		for (i = 0 ; i < sizeof(scp->io) / sizeof(*scp->io) ; i++) {
+		for (i = 0 ; i < nitems(scp->io); i++) {
 			if (scp->io[i] == NULL) {
 				scp->io_rid[i] = i;
 				if (base == 0)
@@ -521,7 +521,7 @@ alloc_resource(sc_p scp)
 				return (1);
 			scp->irq_alloced = 0;
 		}
-		for (i = 0 ; i < sizeof(scp->drq) / sizeof(*scp->drq) ; i++) {
+		for (i = 0 ; i < nitems(scp->drq); i++) {
 			if (scp->drq[i] == NULL) {
 				scp->drq_rid[i] = i;
 				if (base == 0 || i == 0)
@@ -597,7 +597,7 @@ release_resource(sc_p scp)
 	switch(lid) {
 	case LOGICALID_PCM:
 	case LOGICALID_NOPNP:		/* XXX Non-PnP */
-		for (i = 0 ; i < sizeof(scp->io) / sizeof(*scp->io) ; i++) {
+		for (i = 0 ; i < nitems(scp->io); i++) {
 			if (scp->io[i] != NULL) {
 				bus_release_resource(scp->dev, SYS_RES_IOPORT, scp->io_rid[i], scp->io[i]);
 				scp->io[i] = NULL;
@@ -607,7 +607,7 @@ release_resource(sc_p scp)
 			bus_release_resource(scp->dev, SYS_RES_IRQ, scp->irq_rid, scp->irq);
 			scp->irq = NULL;
 		}
-		for (i = 0 ; i < sizeof(scp->drq) / sizeof(*scp->drq) ; i++) {
+		for (i = 0 ; i < nitems(scp->drq); i++) {
 			if (scp->drq[i] != NULL) {
 				bus_release_resource(scp->dev, SYS_RES_DRQ, scp->drq_rid[i], scp->drq[i]);
 				scp->drq[i] = NULL;
diff --git a/sys/dev/speaker/spkr.c b/sys/dev/speaker/spkr.c
index 94d479267337..ec890ff4b666 100644
--- a/sys/dev/speaker/spkr.c
+++ b/sys/dev/speaker/spkr.c
@@ -327,15 +327,13 @@ playstring(char *cp, size_t slen)
 				slen--;
 			} else {
 				GETNUM(cp, octave);
-				if (octave >= sizeof(pitchtab) / sizeof(pitchtab[0]) /
-					OCTAVE_NOTES)
+				if (octave >= nitems(pitchtab) / OCTAVE_NOTES)
 					octave = DFLT_OCTAVE;
 				octprefix = TRUE;
 			}
 			break;
 		case '>':
-			if (octave < sizeof(pitchtab) / sizeof(pitchtab[0]) / 
-				OCTAVE_NOTES - 1)
+			if (octave < nitems(pitchtab) / OCTAVE_NOTES - 1)
 				octave++;
 			octprefix = TRUE;
 			break;
diff --git a/sys/dev/stge/if_stge.c b/sys/dev/stge/if_stge.c
index 0164eb83af37..1ebb05d895ba 100644
--- a/sys/dev/stge/if_stge.c
+++ b/sys/dev/stge/if_stge.c
@@ -416,8 +416,7 @@ stge_probe(device_t dev)
 	vendor = pci_get_vendor(dev);
 	devid = pci_get_device(dev);
 	sp = stge_products;
-	for (i = 0; i < sizeof(stge_products)/sizeof(stge_products[0]);
-	    i++, sp++) {
+	for (i = 0; i < nitems(stge_products); i++, sp++) {
 		if (vendor == sp->stge_vendorid &&
 		    devid == sp->stge_deviceid) {
 			device_set_desc(dev, sp->stge_name);
diff --git a/sys/dev/vkbd/vkbd.c b/sys/dev/vkbd/vkbd.c
index fc5452a98279..6bfd5e9f298c 100644
--- a/sys/dev/vkbd/vkbd.c
+++ b/sys/dev/vkbd/vkbd.c
@@ -380,11 +380,11 @@ vkbd_dev_write(struct cdev *dev, struct uio *uio, int flag)
 	while (uio->uio_resid >= sizeof(q->q[0])) {
 		if (q->head == q->tail) {
 			if (q->cc == 0)
-				avail = sizeof(q->q)/sizeof(q->q[0]) - q->head;
+				avail = nitems(q->q) - q->head;
 			else
 				avail = 0; /* queue must be full */
 		} else if (q->head < q->tail)
-			avail = sizeof(q->q)/sizeof(q->q[0]) - q->tail;
+			avail = nitems(q->q) - q->tail;
 		else
 			avail = q->head - q->tail;
 
@@ -410,7 +410,7 @@ vkbd_dev_write(struct cdev *dev, struct uio *uio, int flag)
 
 			q->cc += avail;
 			q->tail += avail;
-			if (q->tail == sizeof(q->q)/sizeof(q->q[0]))
+			if (q->tail == nitems(q->q))
 				q->tail = 0;
 
 			/* queue interrupt task if needed */
@@ -459,7 +459,7 @@ vkbd_dev_poll(struct cdev *dev, int events, struct thread *td)
 	}
 
 	if (events & (POLLOUT | POLLWRNORM)) {
-		if (q->cc < sizeof(q->q)/sizeof(q->q[0]))
+		if (q->cc < nitems(q->q))
 			revents |= events & (POLLOUT | POLLWRNORM);
 		else
 			selrecord(td, &state->ks_wsel);
@@ -524,7 +524,7 @@ vkbd_data_read(vkbd_state_t *state, int wait)
 	/* get first code from the queue */
 	q->cc --;
 	c = q->q[q->head ++];
-	if (q->head == sizeof(q->q)/sizeof(q->q[0]))
+	if (q->head == nitems(q->q))
 		q->head = 0;
 
 	/* wakeup ks_inq writers/poll()ers */
@@ -1326,12 +1326,12 @@ typematic(int delay, int rate)
 	int value;
 	int i;
 
-	for (i = sizeof(delays)/sizeof(delays[0]) - 1; i > 0; i --) {
+	for (i = nitems(delays) - 1; i > 0; i --) {
 		if (delay >= delays[i])
 			break;
 	}
 	value = i << 5;
-	for (i = sizeof(rates)/sizeof(rates[0]) - 1; i > 0; i --) {
+	for (i = nitems(rates) - 1; i > 0; i --) {
 		if (rate >= rates[i])
 			break;
 	}
diff --git a/sys/dev/wbwd/wbwd.c b/sys/dev/wbwd/wbwd.c
index 75fbea4a5933..7ed2d487e72b 100644
--- a/sys/dev/wbwd/wbwd.c
+++ b/sys/dev/wbwd/wbwd.c
@@ -619,7 +619,7 @@ wb_probe_enable(device_t dev, int probe)
 
 	error = ENXIO;
 	found = 0;
-	for (i = 0; i < sizeof(probe_addrs) / sizeof(*probe_addrs); i++) {
+	for (i = 0; i < nitems(probe_addrs); i++) {
 
 		if (sc != NULL) {
 			/* Allocate bus resources for IO index/data register access. */
@@ -657,7 +657,7 @@ wb_probe_enable(device_t dev, int probe)
 			goto cleanup;
 		}
 
-		for (j = 0; j < sizeof(wb_devs) / sizeof(*wb_devs); j++) {
+		for (j = 0; j < nitems(wb_devs); j++) {
 			if (wb_devs[j].device_id == dev_id) {
 				found = 1;
 				break;