diff --git a/share/man/man9/rwlock.9 b/share/man/man9/rwlock.9
index 94e53a154883..4bc831239422 100644
--- a/share/man/man9/rwlock.9
+++ b/share/man/man9/rwlock.9
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 25, 2007
+.Dd March 16, 2008
 .Dt RWLOCK 9
 .Os
 .Sh NAME
@@ -36,6 +36,7 @@
 .Nm rw_wlock ,
 .Nm rw_runlock ,
 .Nm rw_wunlock ,
+.Nm rw_unlock ,
 .Nm rw_try_upgrade ,
 .Nm rw_downgrade ,
 .Nm rw_sleep ,
@@ -62,6 +63,8 @@
 .Fn rw_runlock "struct rwlock *rw"
 .Ft void
 .Fn rw_wunlock "struct rwlock *rw"
+.Ft void
+.Fn rw_unlock "struct rwlock *rw"
 .Ft int
 .Fn rw_try_upgrade "struct rwlock *rw"
 .Ft void
@@ -179,6 +182,11 @@ This function releases a shared lock previously acquired by
 .It Fn rw_wunlock "struct rwlock *rw"
 This function releases an exclusive lock previously acquired by
 .Fn rw_wlock .
+.It Fn rw_unlock "struct rwlock *rw"
+This function releases a shared lock previously acquired by
+.Fn rw_rlock
+or an exclusive lock previously acquired by
+.Fn rw_wlock .
 .It Fn rw_try_upgrade "struct rwlock *rw"
 Attempt to upgrade a single shared lock to an exclusive lock.
 The current thread must hold a shared lock of
diff --git a/sys/sys/rwlock.h b/sys/sys/rwlock.h
index fe7127b7354a..d793e341a207 100644
--- a/sys/sys/rwlock.h
+++ b/sys/sys/rwlock.h
@@ -167,6 +167,12 @@ void	_rw_assert(struct rwlock *rw, int what, const char *file, int line);
 #define	rw_runlock(rw)		_rw_runlock((rw), LOCK_FILE, LOCK_LINE)
 #define	rw_try_upgrade(rw)	_rw_try_upgrade((rw), LOCK_FILE, LOCK_LINE)
 #define	rw_downgrade(rw)	_rw_downgrade((rw), LOCK_FILE, LOCK_LINE)
+#define	rw_unlock(rw)	do {						\
+	if (rw_wowned(rw))						\
+		rw_wunlock(rw);						\
+	else								\
+		rw_runlock(rw);						\
+} while (0)
 #define	rw_sleep(chan, rw, pri, wmesg, timo)				\
 	_sleep((chan), &(rw)->lock_object, (pri), (wmesg), (timo))