diff --git a/sys/dev/aac/aac.c b/sys/dev/aac/aac.c
index 36996177738..4ff1640ab84 100644
--- a/sys/dev/aac/aac.c
+++ b/sys/dev/aac/aac.c
@@ -212,7 +212,7 @@ static struct aac_mntinforesp *
 
 static struct cdevsw aac_cdevsw = {
 	.d_version =	D_VERSION,
-	.d_flags =	D_NEEDGIANT,
+	.d_flags =	D_NEEDGIANT | D_TRACKCLOSE,
 	.d_open =	aac_open,
 	.d_close =	aac_close,
 	.d_ioctl =	aac_ioctl,
@@ -660,9 +660,6 @@ aac_detach(device_t dev)
 	sc = device_get_softc(dev);
 	fwprintf(sc, HBA_FLAGS_DBG_FUNCTION_ENTRY_B, "");
 
-	if (sc->aac_state & AAC_STATE_OPEN)
-		return(EBUSY);
-
 	callout_drain(&sc->aac_daemontime);
 
 	/* Remove the child containers */
@@ -2804,8 +2801,7 @@ aac_open(struct cdev *dev, int flags, int fmt, struct thread *td)
 
 	sc = dev->si_drv1;
 	fwprintf(sc, HBA_FLAGS_DBG_FUNCTION_ENTRY_B, "");
-	sc->aac_open_cnt++;
-	sc->aac_state |= AAC_STATE_OPEN;
+	device_busy(sc->aac_dev);
 
 	return 0;
 }
@@ -2817,10 +2813,7 @@ aac_close(struct cdev *dev, int flags, int fmt, struct thread *td)
 
 	sc = dev->si_drv1;
 	fwprintf(sc, HBA_FLAGS_DBG_FUNCTION_ENTRY_B, "");
-	sc->aac_open_cnt--;
-	/* Mark this unit as no longer open  */
-	if (sc->aac_open_cnt == 0)
-		sc->aac_state &= ~AAC_STATE_OPEN;
+	device_unbusy(sc->aac_dev);
 
 	return 0;
 }
diff --git a/sys/dev/aac/aacvar.h b/sys/dev/aac/aacvar.h
index 29eb8169e02..192616b34de 100644
--- a/sys/dev/aac/aacvar.h
+++ b/sys/dev/aac/aacvar.h
@@ -319,10 +319,9 @@ struct aac_softc
 	/* controller features, limits and status */
 	int			aac_state;
 #define AAC_STATE_SUSPEND	(1<<0)
-#define	AAC_STATE_OPEN		(1<<1)
+#define	AAC_STATE_UNUSED0	(1<<1)
 #define AAC_STATE_INTERRUPTS_ON	(1<<2)
 #define AAC_STATE_AIF_SLEEPER	(1<<3)
-	int			aac_open_cnt;
 	struct FsaRevision		aac_revision;
 
 	/* controller hardware interface */