--- a/sys/cddl/contrib/opensolaris/uts/common/sys/sysmacros.h
+++ b/sys/cddl/contrib/opensolaris/uts/common/sys/sysmacros.h
@@ -383,7 +383,7 @@
  * High order bit is 31 (or 63 in _LP64 kernel).
  */
 static __inline int
-highbit(ulong_t i)
+highbit(unsigned long i)
 {
 #if defined(__FreeBSD__) && defined(_KERNEL) && defined(HAVE_INLINE_FLSL)
 	return (flsl(i));