Index: sys/cam/cam_xpt.c
===================================================================
--- sys/cam/cam_xpt.c
+++ sys/cam/cam_xpt.c
@@ -2893,8 +2893,7 @@
 				start_ccb->ccb_h.flags |= CAM_DEV_QFREEZE;
 			}
 
-			callout_reset(&dev->callout,
-			    (crs->release_timeout * hz) / 1000,
+			callout_reset_msec(&dev->callout, crs->release_timeout,
 			    xpt_release_devq_timeout, dev);
 
 			dev->flags |= CAM_DEV_REL_TIMEOUT_PENDING;
@@ -4944,7 +4943,7 @@
 	periphdriver_init(1);
 	xpt_hold_boot();
 	callout_init(&xsoftc.boot_callout, 1);
-	callout_reset(&xsoftc.boot_callout, hz * xsoftc.boot_delay / 1000,
+	callout_reset_msec(&xsoftc.boot_callout, xsoftc.boot_delay,
 	    xpt_boot_delay, NULL);
 	/* Fire up rescan thread. */
 	if (kproc_kthread_add(xpt_scanner_thread, NULL, &cam_proc, NULL, 0, 0,
Index: sys/dev/advansys/advansys.c
===================================================================
--- sys/dev/advansys/advansys.c
+++ sys/dev/advansys/advansys.c
@@ -168,9 +168,9 @@
 			ccb_h = LIST_FIRST(&adv->pending_ccbs);
 			while (ccb_h != NULL) {
 				cinfo = ccb_h->ccb_cinfo_ptr;
-				callout_reset(&cinfo->timer,
-				    ccb_h->timeout * hz / 1000, adv_timeout,
-				    ccb_h);
+				callout_reset_msec(&cinfo->timer,
+				    ccb_h->timeout,
+				    adv_timeout, ccb_h);
 				ccb_h = LIST_NEXT(ccb_h, sim_links.le);
 			}
 			adv->state &= ~ADV_IN_TIMEOUT;
@@ -569,7 +569,7 @@
 	ccb_h->status |= CAM_SIM_QUEUED;
 	LIST_INSERT_HEAD(&adv->pending_ccbs, ccb_h, sim_links.le);
 	/* Schedule our timeout */
-	callout_reset(&cinfo->timer, ccb_h->timeout * hz /1000, adv_timeout,
+	callout_reset_msec(&cinfo->timer, ccb_h->timeout, adv_timeout,
 	    csio);
 }
 
Index: sys/dev/advansys/adwcam.c
===================================================================
--- sys/dev/advansys/adwcam.c
+++ sys/dev/advansys/adwcam.c
@@ -322,8 +322,7 @@
 	acb->state |= ACB_ACTIVE;
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	LIST_INSERT_HEAD(&adw->pending_ccbs, &ccb->ccb_h, sim_links.le);
-	callout_reset(&acb->timer, (ccb->ccb_h.timeout * hz) / 1000,
-	    adwtimeout, acb);
+	callout_reset_msec(&acb->timer, ccb->ccb_h.timeout, adwtimeout, acb);
 
 	adw_send_acb(adw, acb, acbvtob(adw, acb));
 }
Index: sys/dev/aha/aha.c
===================================================================
--- sys/dev/aha/aha.c
+++ sys/dev/aha/aha.c
@@ -1047,8 +1047,7 @@
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	LIST_INSERT_HEAD(&aha->pending_ccbs, &ccb->ccb_h, sim_links.le);
 
-	callout_reset(&accb->timer, (ccb->ccb_h.timeout * hz) / 1000,
-	    ahatimeout, accb);
+	callout_reset_msec(&accb->timer, ccb->ccb_h.timeout, ahatimeout, accb);
 
 	/* Tell the adapter about this command */
 	if (aha->cur_outbox->action_code != AMBO_FREE) {
@@ -1181,9 +1180,8 @@
 				ccb_h = LIST_NEXT(ccb_h, sim_links.le);
 				ahadone(aha, pending_accb, AMBI_ERROR);
 			} else {
-				callout_reset(&pending_accb->timer,
-				    (ccb_h->timeout * hz) / 1000,
-				    ahatimeout, pending_accb);
+				callout_reset_msec(&pending_accb->timer,
+				    ccb_h->timeout, ahatimeout, pending_accb);
 				ccb_h = LIST_NEXT(ccb_h, sim_links.le);
 			}
 		}
Index: sys/dev/ahb/ahb.c
===================================================================
--- sys/dev/ahb/ahb.c
+++ sys/dev/ahb/ahb.c
@@ -616,9 +616,8 @@
 			xpt_done(ccb);
 		} else if (ahb->immed_ecb != NULL) {
 			/* Re-instate timeout */
-			callout_reset(&pending_ecb->timer, 
-			    (ccb->ccb_h.timeout * hz) / 1000,
-			    ahbtimeout, pending_ecb);
+			callout_reset_msec(&pending_ecb->timer,
+			    ccb->ccb_h.timeout, ahbtimeout, pending_ecb);
 		}
 	}
 
@@ -985,7 +984,7 @@
 	/* Tell the adapter about this command */
 	ahbqueuembox(ahb, ecb_paddr, ATTN_STARTECB|ccb->ccb_h.target_id);
 
-	callout_reset(&ecb->timer, (ccb->ccb_h.timeout * hz) / 1000, ahbtimeout,
+	callout_reset_msec(&ecb->timer, ccb->ccb_h.timeout, ahbtimeout,
 	    ecb);
 }
 
Index: sys/dev/ahci/ahci.c
===================================================================
--- sys/dev/ahci/ahci.c
+++ sys/dev/ahci/ahci.c
@@ -1582,7 +1582,8 @@
 		return;
 	}
 	/* Start command execution timeout */
-	callout_reset(&slot->timeout, (int)ccb->ccb_h.timeout * hz / 2000,
+	callout_reset(&slot->timeout,
+	    MSECS_TO_TICKS_FACTOR(ccb->ccb_h.timeout, 2),
 	    (timeout_t*)ahci_timeout, slot);
 	return;
 }
@@ -1619,7 +1620,7 @@
 		if ((ch->toslots & (1 << i)) == 0)
 			continue;
 		callout_reset(&slot->timeout,
-		    (int)slot->ccb->ccb_h.timeout * hz / 2000,
+    	    	    MSECS_TO_TICKS_FACTOR(slot->ccb->ccb_h.timeout, 2),
 		    (timeout_t*)ahci_timeout, slot);
 	}
 }
@@ -1653,7 +1654,7 @@
 		}
 
 		callout_reset(&slot->timeout,
-		    (int)slot->ccb->ccb_h.timeout * hz / 2000,
+	    	    MSECS_TO_TICKS_FACTOR(slot->ccb->ccb_h.timeout, 2),
 		    (timeout_t*)ahci_timeout, slot);
 		return;
 	}
Index: sys/dev/aic/aic.c
===================================================================
--- sys/dev/aic/aic.c
+++ sys/dev/aic/aic.c
@@ -319,8 +319,7 @@
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	TAILQ_INSERT_TAIL(&aic->pending_ccbs, &ccb->ccb_h, sim_links.tqe);
 
-	callout_reset(&scb->timer, (ccb->ccb_h.timeout * hz) / 1000,
-	    aic_timeout, scb);
+	callout_reset_msec(&scb->timer, ccb->ccb_h.timeout, aic_timeout, scb);
 
 	aic_start(aic);
 }
@@ -1075,9 +1074,8 @@
 				    &pending_scb->ccb->ccb_h, sim_links.tqe);
 				aic_done(aic, pending_scb);
 			} else {
-				callout_reset(&pending_scb->timer,
-				    (ccb_h->timeout * hz) / 1000, aic_timeout,
-				    pending_scb);
+				callout_reset_msec(&pending_scb->timer,
+				    ccb_h->timeout, aic_timeout, pending_scb);
 				ccb_h = TAILQ_NEXT(ccb_h, sim_links.tqe);
 			}
 		}
@@ -1094,9 +1092,8 @@
 				    &nexus_scb->ccb->ccb_h, sim_links.tqe);
 				aic_done(aic, nexus_scb);
 			} else {
-				callout_reset(&nexus_scb->timer,
-				    (ccb_h->timeout * hz) / 1000, aic_timeout,
-				    nexus_scb);
+				callout_reset_msec(&nexus_scb->timer,
+				    ccb_h->timeout, aic_timeout, nexus_scb);
 				ccb_h = TAILQ_NEXT(ccb_h, sim_links.tqe);
 			}
 		}
Index: sys/dev/arcmsr/arcmsr.c
===================================================================
--- sys/dev/arcmsr/arcmsr.c
+++ sys/dev/arcmsr/arcmsr.c
@@ -2705,7 +2705,8 @@
 	if (pccb->ccb_h.timeout != CAM_TIME_INFINITY)
 	{
 		arcmsr_callout_init(&srb->ccb_callout);
-		callout_reset(&srb->ccb_callout, ((pccb->ccb_h.timeout + (ARCMSR_TIMEOUT_DELAY * 1000)) * hz) / 1000, arcmsr_srb_timeout, srb);
+		callout_reset_msec(&srb->ccb_callout, pccb->ccb_h.timeout +
+		    (ARCMSR_TIMEOUT_DELAY * 1000), arcmsr_srb_timeout, srb);
 		srb->srb_flags |= SRB_FLAG_TIMER_START;
 	}
 }
Index: sys/dev/asr/asr.c
===================================================================
--- sys/dev/asr/asr.c
+++ sys/dev/asr/asr.c
@@ -813,7 +813,7 @@
 			ccb->ccb_h.timeout = 6 * 60 * 1000;
 		}
 		set_ccb_timeout_ch(ccb, timeout(asr_timeout, (caddr_t)ccb,
-		  (ccb->ccb_h.timeout * hz) / 1000));
+		    MSECS_TO_TICKS(ccb->ccb_h.timeout));
 	}
 	splx(s);
 } /* ASR_ccbAdd */
@@ -1338,8 +1338,8 @@
 		if (ASR_reset (sc) == ENXIO) {
 			/* Try again later */
 			set_ccb_timeout_ch(ccb, timeout(asr_timeout,
-			  (caddr_t)ccb,
-			  (ccb->ccb_h.timeout * hz) / 1000));
+			    (caddr_t)ccb,
+			    MSECS_TO_TICKS(ccb->ccb_h.timeout));
 		}
 		return;
 	}
@@ -1354,8 +1354,8 @@
 		debug_asr_printf (" AGAIN\nreinitializing adapter\n");
 		if (ASR_reset (sc) == ENXIO) {
 			set_ccb_timeout_ch(ccb, timeout(asr_timeout,
-			  (caddr_t)ccb,
-			  (ccb->ccb_h.timeout * hz) / 1000));
+			    (caddr_t)ccb,
+			    MSECS_TO_TICKS(ccb->ccb_h.timeout));
 		}
 		splx(s);
 		return;
@@ -1365,7 +1365,7 @@
 	ccb->ccb_h.status &= ~CAM_STATUS_MASK;
 	ccb->ccb_h.status |= CAM_CMD_TIMEOUT;
 	set_ccb_timeout_ch(ccb, timeout(asr_timeout, (caddr_t)ccb,
-	  (ccb->ccb_h.timeout * hz) / 1000));
+	    MSECS_TO_TICKS(ccb->ccb_h.timeout));
 	ASR_resetBus (sc, cam_sim_bus(xpt_path_sim(ccb->ccb_h.path)));
 	xpt_async (AC_BUS_RESET, ccb->ccb_h.path, NULL);
 	splx(s);
Index: sys/dev/buslogic/bt.c
===================================================================
--- sys/dev/buslogic/bt.c
+++ sys/dev/buslogic/bt.c
@@ -1465,8 +1465,7 @@
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	LIST_INSERT_HEAD(&bt->pending_ccbs, &ccb->ccb_h, sim_links.le);
 
-	callout_reset(&bccb->timer, (ccb->ccb_h.timeout * hz) / 1000,
-	    bttimeout, bccb);
+	callout_reset_msec(&bccb->timer, ccb->ccb_h.timeout, bttimeout, bccb);
 
 	/* Tell the adapter about this command */
 	bt->cur_outbox->ccb_addr = btccbvtop(bt, bccb);
@@ -1600,9 +1599,8 @@
 				ccb_h = LIST_NEXT(ccb_h, sim_links.le);
 				btdone(bt, pending_bccb, BMBI_ERROR);
 			} else {
-				callout_reset(&pending_bccb->timer,
-				    (ccb_h->timeout * hz) / 1000,
-				    bttimeout, pending_bccb);
+				callout_reset_msec(&pending_bccb->timer,
+				    ccb_h->timeout, bttimeout, pending_bccb);
 				ccb_h = LIST_NEXT(ccb_h, sim_links.le);
 			}
 		}
Index: sys/dev/ciss/ciss.c
===================================================================
--- sys/dev/ciss/ciss.c
+++ sys/dev/ciss/ciss.c
@@ -147,9 +147,9 @@
 static void	ciss_perf_msi_intr(void *arg);
 static void	ciss_complete(struct ciss_softc *sc, cr_qhead_t *qh);
 static int	_ciss_report_request(struct ciss_request *cr, int *command_status, int *scsi_status, const char *func);
-static int	ciss_synch_request(struct ciss_request *cr, int timeout);
-static int	ciss_poll_request(struct ciss_request *cr, int timeout);
-static int	ciss_wait_request(struct ciss_request *cr, int timeout);
+static int	ciss_synch_request(struct ciss_request *cr, u_int32_t timeout);
+static int	ciss_poll_request(struct ciss_request *cr, u_int32_t timeout);
+static int	ciss_wait_request(struct ciss_request *cr, u_int32_t timeout);
 #if 0
 static int	ciss_abort_request(struct ciss_request *cr);
 #endif
@@ -2354,7 +2354,7 @@
  * completion.
  */
 static int
-ciss_synch_request(struct ciss_request *cr, int timeout)
+ciss_synch_request(struct ciss_request *cr, u_int32_t timeout)
 {
     if (cr->cr_sc->ciss_flags & CISS_FLAG_RUNNING) {
 	return(ciss_wait_request(cr, timeout));
@@ -2369,7 +2369,7 @@
  * Timeout in milliseconds.
  */
 static int
-ciss_poll_request(struct ciss_request *cr, int timeout)
+ciss_poll_request(struct ciss_request *cr, u_int32_t timeout)
 {
     cr_qhead_t qh;
     struct ciss_softc *sc;
@@ -2403,7 +2403,7 @@
  * the timeout.
  */
 static int
-ciss_wait_request(struct ciss_request *cr, int timeout)
+ciss_wait_request(struct ciss_request *cr, u_int32_t timeout)
 {
     int		error;
 
@@ -2414,7 +2414,8 @@
 	return(error);
 
     while ((cr->cr_flags & CISS_REQ_SLEEP) && (error != EWOULDBLOCK)) {
-	error = msleep(cr, &cr->cr_sc->ciss_mtx, PRIBIO, "cissREQ", (timeout * hz) / 1000);
+	error = msleep(cr, &cr->cr_sc->ciss_mtx, PRIBIO, "cissREQ",
+	    MSECS_TO_TICKS(timeout));
     }
     return(error);
 }
Index: sys/dev/dpt/dpt_scsi.c
===================================================================
--- sys/dev/dpt/dpt_scsi.c
+++ sys/dev/dpt/dpt_scsi.c
@@ -793,8 +793,7 @@
 	dccb->state |= DCCB_ACTIVE;
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	LIST_INSERT_HEAD(&dpt->pending_ccb_list, &ccb->ccb_h, sim_links.le);
-	callout_reset(&dccb->timer, (ccb->ccb_h.timeout * hz) / 1000,
-	    dpttimeout, dccb);
+	callout_reset_msec(&dccb->timer, ccb->ccb_h.timeout, dpttimeout, dccb);
 	if (dpt_send_eata_command(dpt, &dccb->eata_ccb,
 				  dccb->eata_ccb.cp_busaddr,
 				  EATA_CMD_DMA_SEND_CP, 0, 0, 0, 0) != 0) {
Index: sys/dev/firewire/sbp.c
===================================================================
--- sys/dev/firewire/sbp.c
+++ sys/dev/firewire/sbp.c
@@ -1028,8 +1028,8 @@
 sbp_scan_dev(struct sbp_dev *sdev)
 {
 	sdev->status = SBP_DEV_PROBE;
-	callout_reset(&sdev->target->scan_callout, scan_delay * hz / 1000,
-			sbp_cam_scan_target, (void *)sdev->target);
+	callout_reset_msec(&sdev->target->scan_callout, scan_delay,
+	    sbp_cam_scan_target, (void *)sdev->target);
 }
 
 static void
@@ -2699,9 +2699,10 @@
 	prev2 = prev = STAILQ_LAST(&sdev->ocbs, sbp_ocb, ocb);
 	STAILQ_INSERT_TAIL(&sdev->ocbs, ocb, ocb);
 
-	if (ocb->ccb != NULL)
-		callout_reset(&ocb->timer, (ocb->ccb->ccb_h.timeout * hz) / 1000,
+	if (ocb->ccb != NULL) {
+		callout_reset_msec(&ocb->timer, ocb->ccb->ccb_h.timeout,
 		    sbp_timeout, ocb);
+	}
 
 	if (use_doorbell && prev == NULL)
 		prev2 = sdev->last_ocb;
Index: sys/dev/glxiic/glxiic.c
===================================================================
--- sys/dev/glxiic/glxiic.c
+++ sys/dev/glxiic/glxiic.c
@@ -559,8 +559,7 @@
 
 	GLXIIC_ASSERT_LOCKED(sc);
 
-	callout_reset(&sc->callout, sc->timeout * 1000 / hz, glxiic_timeout,
-	    sc);
+	callout_reset_msec(&sc->callout, sc->timeout, glxiic_timeout, sc);
 }
 
 static void
Index: sys/dev/hpt27xx/hpt27xx_os_bsd.c
===================================================================
--- sys/dev/hpt27xx/hpt27xx_os_bsd.c
+++ sys/dev/hpt27xx/hpt27xx_os_bsd.c
@@ -240,7 +240,7 @@
 
 	HPT_ASSERT(vbus_ext->ext_type==EXT_TYPE_VBUS);
 
-	callout_reset(&vbus_ext->timer, interval * hz / 1000000,
+	callout_reset(&vbus_ext->timer, MSECS_TO_TICKS_FACTOR(interval, 1000),
 	    os_timer_for_ldm, vbus_ext);
 }
 
Index: sys/dev/hptnr/hptnr_os_bsd.c
===================================================================
--- sys/dev/hptnr/hptnr_os_bsd.c
+++ sys/dev/hptnr/hptnr_os_bsd.c
@@ -235,7 +235,7 @@
 
 	HPT_ASSERT(vbus_ext->ext_type==EXT_TYPE_VBUS);
 
-	callout_reset(&vbus_ext->timer, interval * hz / 1000000,
+	callout_reset(&vbus_ext->timer, MSECS_TO_TICKS_FACTOR(interval, 1000),
 	    os_timer_for_ldm, vbus_ext);
 }
 
Index: sys/dev/hptrr/hptrr_os_bsd.c
===================================================================
--- sys/dev/hptrr/hptrr_os_bsd.c
+++ sys/dev/hptrr/hptrr_os_bsd.c
@@ -221,7 +221,7 @@
 
 	HPT_ASSERT(vbus_ext->ext_type==EXT_TYPE_VBUS);
 
-	callout_reset(&vbus_ext->timer, interval * hz / 1000000,
+	callout_reset(&vbus_ext->timer, MSECS_TO_TICKS_FACTOR(interval, 1000),
 	    os_timer_for_ldm, vbus_ext);
 }
 
Index: sys/dev/hyperv/storvsc/hv_storvsc_drv_freebsd.c
===================================================================
--- sys/dev/hyperv/storvsc/hv_storvsc_drv_freebsd.c
+++ sys/dev/hyperv/storvsc/hv_storvsc_drv_freebsd.c
@@ -983,9 +983,8 @@
 		mtx_unlock(&sc->hs_lock);
 
 		reqp->retries++;
-		callout_reset(&reqp->callout,
-				(ccb->ccb_h.timeout * hz) / 1000,
-				storvsc_timeout, reqp);
+		callout_reset_msec(&reqp->callout, ccb->ccb_h.timeout,
+		    storvsc_timeout, reqp);
 #if HVS_TIMEOUT_TEST
 		storvsc_timeout_test(reqp, SEND_DIAGNOSTIC, 0);
 #endif
@@ -1158,9 +1157,8 @@
 
 		if (ccb->ccb_h.timeout != CAM_TIME_INFINITY) {
 			callout_init(&reqp->callout, CALLOUT_MPSAFE);
-			callout_reset(&reqp->callout,
-					(ccb->ccb_h.timeout * hz) / 1000,
-					storvsc_timeout, reqp);
+			callout_reset_msec(&reqp->callout, ccb->ccb_h.timeout,
+			    storvsc_timeout, reqp);
 #if HVS_TIMEOUT_TEST
 			cv_init(&reqp->event.cv, "storvsc timeout cv");
 			mtx_init(&reqp->event.mtx, "storvsc timeout mutex",
Index: sys/dev/iir/iir.c
===================================================================
--- sys/dev/iir/iir.c
+++ sys/dev/iir/iir.c
@@ -1240,9 +1240,8 @@
     
     ccb->ccb_h.status |= CAM_SIM_QUEUED;
     /* timeout handling */
-    gccb->gc_timeout_ch =
-        timeout(iir_timeout, (caddr_t)gccb,
-                (ccb->ccb_h.timeout * hz) / 1000);
+    gccb->gc_timeout_ch = timeout(iir_timeout, (caddr_t)gccb,
+	    MSECS_TO_TICKS(ccb->ccb_h.timeout));
 
     gdt->sc_copy_cmd(gdt, gccb);
     splx(lock);
Index: sys/dev/isci/isci_timer.c
===================================================================
--- sys/dev/isci/isci_timer.c
+++ sys/dev/isci/isci_timer.c
@@ -79,7 +79,7 @@
 
 	isci_timer->is_started = TRUE;
 	isci_log_message(3, "TIMER", "start %p %d\n", timer, milliseconds);
-	callout_reset(&isci_timer->callout, (milliseconds * hz)/1000,
+	callout_reset_msec(&isci_timer->callout, milliseconds,
 	    isci_timer_timeout, timer);
 }
 
Index: sys/dev/mpr/mpr_sas.c
===================================================================
--- sys/dev/mpr/mpr_sas.c
+++ sys/dev/mpr/mpr_sas.c
@@ -1903,7 +1903,7 @@
 		cm->cm_desc.SCSIIO.DevHandle = htole16(targ->handle);
 	}
 
-	callout_reset(&cm->cm_callout, (ccb->ccb_h.timeout * hz) / 1000,
+	callout_reset_msec(&cm->cm_callout, ccb->ccb_h.timeout,
 	   mprsas_scsiio_timeout, cm);
 
 	targ->issued++;
Index: sys/dev/mps/mps_sas.c
===================================================================
--- sys/dev/mps/mps_sas.c
+++ sys/dev/mps/mps_sas.c
@@ -1839,7 +1839,7 @@
 		}
 	}
 
-	callout_reset(&cm->cm_callout, (ccb->ccb_h.timeout * hz) / 1000,
+	callout_reset_msec(&cm->cm_callout, ccb->ccb_h.timeout,
 	   mpssas_scsiio_timeout, cm);
 
 	targ->issued++;
Index: sys/dev/mpt/mpt.c
===================================================================
--- sys/dev/mpt/mpt.c
+++ sys/dev/mpt/mpt.c
@@ -1330,7 +1330,7 @@
 	 * our sleep mode.
 	 */
 	if (sleep_ok != 0) {
-		timeout = (time_ms * hz) / 1000;
+		timeout = MSECS_TO_TICKS(time_ms);
 	} else {
 		timeout = time_ms * 2;
 	}
Index: sys/dev/mpt/mpt_cam.c
===================================================================
--- sys/dev/mpt/mpt_cam.c
+++ sys/dev/mpt/mpt_cam.c
@@ -1630,7 +1630,7 @@
 
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	if (ccb->ccb_h.timeout != CAM_TIME_INFINITY) {
-		mpt_req_timeout(req, (ccb->ccb_h.timeout * hz) / 1000,
+		mpt_req_timeout(req, MSECS_TO_TICKS(ccb->ccb_h.timeout),
 		    mpt_timeout, ccb);
 	}
 	if (mpt->verbose > MPT_PRT_DEBUG) {
@@ -2016,7 +2016,7 @@
 
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	if (ccb->ccb_h.timeout != CAM_TIME_INFINITY) {
-		mpt_req_timeout(req, (ccb->ccb_h.timeout * hz) / 1000,
+		mpt_req_timeout(req, MSECS_TO_TICKS(ccb->ccb_h.timeout),
 		    mpt_timeout, ccb);
 	}
 	if (mpt->verbose > MPT_PRT_DEBUG) {
Index: sys/dev/mrsas/mrsas_cam.c
===================================================================
--- sys/dev/mrsas/mrsas_cam.c
+++ sys/dev/mrsas/mrsas_cam.c
@@ -378,8 +378,7 @@
 	 * on OCR enable/disable property of Controller from ocr_thread
 	 * context.
 	 */
-	callout_reset(&cmd->cm_callout, (600000 * hz) / 1000,
-	    mrsas_scsiio_timeout, cmd);
+	callout_reset_msec(&cmd->cm_callout, 600000, mrsas_scsiio_timeout, cmd);
 	sc->do_timedout_reset = 1;
 	if (sc->ocr_thread_active)
 		wakeup(&sc->ocr_chan);
@@ -530,7 +529,7 @@
 	/*
 	 * Start timer for IO timeout. Default timeout value is 90 second.
 	 */
-	callout_reset(&cmd->cm_callout, (sc->mrsas_io_timeout * hz) / 1000,
+	callout_reset_msec(&cmd->cm_callout, sc->mrsas_io_timeout,
 	    mrsas_scsiio_timeout, cmd);
 	mrsas_atomic_inc(&sc->fw_outstanding);
 
Index: sys/dev/mvs/mvs.c
===================================================================
--- sys/dev/mvs/mvs.c
+++ sys/dev/mvs/mvs.c
@@ -1415,7 +1415,7 @@
 		}
 	}
 	/* Start command execution timeout */
-	callout_reset(&slot->timeout, (int)ccb->ccb_h.timeout * hz / 1000,
+	callout_reset_msec(&slot->timeout, ccb->ccb_h.timeout,
 	    (timeout_t*)mvs_timeout, slot);
 }
 
@@ -1529,7 +1529,7 @@
 	ATA_OUTL(ch->r_mem, EDMA_REQQIP,
 	    ch->dma.workrq_bus + MVS_CRQB_OFFSET + (MVS_CRQB_SIZE * ch->out_idx));
 	/* Start command execution timeout */
-	callout_reset(&slot->timeout, (int)ccb->ccb_h.timeout * hz / 1000,
+	callout_reset_msec(&slot->timeout, ccb->ccb_h.timeout,
 	    (timeout_t*)mvs_timeout, slot);
 	return;
 }
@@ -1568,7 +1568,7 @@
 		if ((ch->toslots & (1 << i)) == 0)
 			continue;
 		callout_reset(&slot->timeout,
-		    (int)slot->ccb->ccb_h.timeout * hz / 2000,
+		    MSECS_TO_TICKS_FACTOR(slot->ccb->ccb_h.timeout, 2),
 		    (timeout_t*)mvs_timeout, slot);
 	}
 }
Index: sys/dev/siis/siis.c
===================================================================
--- sys/dev/siis/siis.c
+++ sys/dev/siis/siis.c
@@ -1120,7 +1120,7 @@
 	ATA_OUTL(ch->r_mem, SIIS_P_CACTL(slot->slot), prb_bus);
 	ATA_OUTL(ch->r_mem, SIIS_P_CACTH(slot->slot), prb_bus >> 32);
 	/* Start command execution timeout */
-	callout_reset(&slot->timeout, (int)ccb->ccb_h.timeout * hz / 1000,
+	callout_reset_msec(&slot->timeout, ccb->ccb_h.timeout,
 	    (timeout_t*)siis_timeout, slot);
 	return;
 }
@@ -1162,8 +1162,7 @@
 			continue;
 		if ((ch->toslots & (1 << i)) == 0)
 			continue;
-		callout_reset(&slot->timeout,
-		    (int)slot->ccb->ccb_h.timeout * hz / 1000,
+		callout_reset_msec(&slot->timeout, slot->ccb->ccb_h.timeout,
 		    (timeout_t*)siis_timeout, slot);
 	}
 }
Index: sys/dev/sym/sym_hipd.c
===================================================================
--- sys/dev/sym/sym_hipd.c
+++ sys/dev/sym/sym_hipd.c
@@ -2329,8 +2329,8 @@
 	assert(!(ccb->ccb_h.status & CAM_SIM_QUEUED));
 	ccb->ccb_h.status = CAM_REQ_INPROG;
 
-	callout_reset(&cp->ch, ccb->ccb_h.timeout * hz / 1000, sym_callout,
-			(caddr_t) ccb);
+	callout_reset_msec(&cp->ch, ccb->ccb_h.timeout, sym_callout,
+	    (caddr_t)ccb);
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 	ccb->ccb_h.sym_hcb_ptr = np;
 
Index: sys/dev/trm/trm.c
===================================================================
--- sys/dev/trm/trm.c
+++ sys/dev/trm/trm.c
@@ -475,7 +475,8 @@
 	ccb->ccb_h.status |= CAM_SIM_QUEUED;
 #if 0
 	/* XXX Need a timeout handler */
-	ccb->ccb_h.timeout_ch = timeout(trmtimeout, (caddr_t)srb, (ccb->ccb_h.timeout * hz) / 1000);
+	ccb->ccb_h.timeout_ch = timeout(trmtimeout, (caddr_t)srb,
+	    MSECS_TO_TICKS(ccb->ccb_h.timeout));
 #endif
 	trm_SendSRB(pACB, pSRB);
 	splx(flags);
Index: sys/dev/tws/tws_cam.c
===================================================================
--- sys/dev/tws/tws_cam.c
+++ sys/dev/tws/tws_cam.c
@@ -747,7 +747,7 @@
      * and submit the I/O.
      */
     sc->stats.scsi_ios++;
-    callout_reset(&req->timeout, (ccb_h->timeout * hz) / 1000, tws_timeout, req);
+    callout_reset_msec(&req->timeout, ccb->ccb_h.timeout, tws_timeout, req);
     error = tws_map_request(sc, req);
     return(error);
 }
Index: sys/dev/virtio/scsi/virtio_scsi.c
===================================================================
--- sys/dev/virtio/scsi/virtio_scsi.c
+++ sys/dev/virtio/scsi/virtio_scsi.c
@@ -1087,7 +1087,7 @@
 
 	if (ccbh->timeout != CAM_TIME_INFINITY) {
 		req->vsr_flags |= VTSCSI_REQ_FLAG_TIMEOUT_SET;
-		callout_reset(&req->vsr_callout, ccbh->timeout * hz / 1000,
+		callout_reset_msec(&req->vsr_callout, ccbh->timeout,
 		    vtscsi_timedout_scsi_cmd, req);
 	}
 
Index: sys/sys/callout.h
===================================================================
--- sys/sys/callout.h
+++ sys/sys/callout.h
@@ -39,6 +39,7 @@
 #define _SYS_CALLOUT_H_
 
 #include <sys/_callout.h>
+#include <sys/time.h>
 
 #define	CALLOUT_LOCAL_ALLOC	0x0001 /* was allocated from callfree */
 #define	CALLOUT_ACTIVE		0x0002 /* callout is currently active */
@@ -62,6 +63,11 @@
 	struct callout *callout;
 };
 
+#define MSECS_TO_TICKS_FACTOR(ms, f) \
+    (int)((u_int64_t)(ms) * (u_int32_t)hz / (1000 * f))
+#define MSECS_TO_TICKS(ms) \
+    MSECS_TO_TICKS_FACTOR(ms, 1)
+
 #ifdef _KERNEL
 #define	callout_active(c)	((c)->c_flags & CALLOUT_ACTIVE)
 #define	callout_deactivate(c)	((c)->c_flags &= ~CALLOUT_ACTIVE)
@@ -89,6 +95,8 @@
         (cpu), C_HARDCLOCK)
 #define	callout_reset(c, on_tick, fn, arg)				\
     callout_reset_on((c), (on_tick), (fn), (arg), (c)->c_cpu)
+#define	callout_reset_msec(c, ms, fn, arg)				\
+    callout_reset(c, MSECS_TO_TICKS(ms), fn, arg)
 #define	callout_reset_curcpu(c, on_tick, fn, arg)			\
     callout_reset_on((c), (on_tick), (fn), (arg), PCPU_GET(cpuid))
 int	callout_schedule(struct callout *, int);