Index: sys/sys/sleepqueue.h
===================================================================
--- sys/sys/sleepqueue.h	(revision 236814)
+++ sys/sys/sleepqueue.h	(working copy)
@@ -108,8 +108,11 @@
 void	sleepq_release(void *wchan);
 void	sleepq_remove(struct thread *td, void *wchan);
 int	sleepq_signal(void *wchan, int flags, int pri, int queue);
-void	sleepq_set_timeout_bt(void *wchan, struct bintime bt);
-void	sleepq_set_timeout(void *wchan, int timo);
+void	_sleepq_set_timeout(void *wchan, struct bintime *bt, int *timo);
+#define	sleepq_set_timeout(wchan, timo)					\
+    _sleepq_set_timeout((wchan), (NULL), (&timo))
+#define	sleepq_set_timeout_bt(wchan, bt)				\
+    _sleepq_set_timeout((wchan), (&bt), (NULL))
 u_int	sleepq_sleepcnt(void *wchan, int queue);
 int	sleepq_timedwait(void *wchan, int pri);
 int	sleepq_timedwait_sig(void *wchan, int pri);
Index: sys/kern/subr_sleepqueue.c
===================================================================
--- sys/kern/subr_sleepqueue.c	(revision 236815)
+++ sys/kern/subr_sleepqueue.c	(working copy)
@@ -362,36 +362,28 @@
  * sleep queue after timo ticks if the thread has not already been awakened.
  */
 void 
-sleepq_set_timeout_bt(void *wchan, struct bintime bt)
+_sleepq_set_timeout(void *wchan, struct bintime *bt, int *timo)
 {
 
 	struct sleepqueue_chain *sc;
 	struct thread *td;
 
+	KASSERT(bt == NULL || timo == NULL, 
+	    ("one between bt and timo should be NULL")); 
 	td = curthread;
 	sc = SC_LOOKUP(wchan);
 	mtx_assert(&sc->sc_lock, MA_OWNED);
 	MPASS(TD_ON_SLEEPQ(td));
 	MPASS(td->td_sleepqueue == NULL);
 	MPASS(wchan != NULL);
-	callout_reset_bt_on(&td->td_slpcallout, bt, sleepq_timeout, td, PCPU_GET(cpuid), 0);
+	if (bt == NULL) 
+		callout_reset_curcpu(&td->td_slpcallout, *timo, 
+		    sleepq_timeout, td);
+	else
+		callout_reset_bt_on(&td->td_slpcallout, *bt, 
+		    sleepq_timeout, td, PCPU_GET(cpuid), 0); 
 }
 
-void
-sleepq_set_timeout(void *wchan, int timo)
-{
-	struct sleepqueue_chain *sc;
-	struct thread *td;
-
-	td = curthread;
-	sc = SC_LOOKUP(wchan);
-	mtx_assert(&sc->sc_lock, MA_OWNED);
-	MPASS(TD_ON_SLEEPQ(td));
-	MPASS(td->td_sleepqueue == NULL);
-	MPASS(wchan != NULL);
-	callout_reset_curcpu(&td->td_slpcallout, timo, sleepq_timeout, td);
-}
-
 /*
  * Return the number of actual sleepers for the specified queue.
  */