diff --git a/sys/sys/ucred.h b/sys/sys/ucred.h
index 463e22f9a69b..6e1926070380 100644
--- a/sys/sys/ucred.h
+++ b/sys/sys/ucred.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: ucred.h,v 1.29 2006/07/13 11:07:19 martin Exp $	*/
+/*	$NetBSD: ucred.h,v 1.30 2006/07/15 06:33:40 yamt Exp $	*/
 
 /*
  * Copyright (c) 1989, 1993
@@ -34,7 +34,6 @@
 #ifndef _SYS_UCRED_H_
 #define	_SYS_UCRED_H_
 
-#include <sys/lock.h>
 #include <sys/param.h>
 
 /*
@@ -51,7 +50,6 @@ struct uucred {
 };
 
 struct ucred {
-	struct simplelock cr_lock;		/* mutex for ref count */
 	uint32_t	cr_ref;			/* reference count */
 #define cr_startcopy	cr_uid			/* for dup & copy */
 	uid_t		cr_uid;			/* effective user id */
@@ -61,14 +59,15 @@ struct ucred {
 };
 
 #ifdef _KERNEL
-static __inline void crhold(struct ucred *cr)
-{
-	simple_lock(&cr->cr_lock);
-	cr->cr_ref++;
-	simple_unlock(&cr->cr_lock);
-}
 
-/* flags that control when do_setres{u,g}id will do anything */
+/*
+ * flags that control when do_setres{u,g}id will do anything
+ *
+ * ID_XXX_EQ_YYY means
+ * "allow modifying XXX uid to the given value if the new value of
+ * XXX uid (or gid) equals the current value of YYY uid (or gid)."
+ */
+
 #define	ID_E_EQ_E	0x001		/* effective equals effective */
 #define	ID_E_EQ_R	0x002		/* effective equals real */
 #define	ID_E_EQ_S	0x004		/* effective equals saved */