Index: sys/kern/kern_lock.c
===================================================================
--- sys/kern/kern_lock.c
+++ sys/kern/kern_lock.c
@@ -984,7 +984,7 @@
 	op = flags & LK_TYPE_MASK;
 	v = lockmgr_read_value(lk);
 	for (;;) {
-		if (LK_SHARERS_LOCK(v) > 1) {
+		if (LK_SHARERS(v) > 1) {
 			if (op == LK_TRYUPGRADE) {
 				LOCK_LOG2(lk, "%s: %p failed the nowait upgrade",
 				    __func__, lk);
Index: sys/sys/lockmgr.h
===================================================================
--- sys/sys/lockmgr.h
+++ sys/sys/lockmgr.h
@@ -50,7 +50,9 @@
 
 #define	LK_HOLDER(x)			((x) & ~LK_FLAGMASK)
 #define	LK_SHARERS_SHIFT		5
+/* How many sharers does this lock have */
 #define	LK_SHARERS(x)			(LK_HOLDER(x) >> LK_SHARERS_SHIFT)
+/* What would be the value of a lock with this many sharers? */
 #define	LK_SHARERS_LOCK(x)		((x) << LK_SHARERS_SHIFT | LK_SHARE)
 #define	LK_ONE_SHARER			(1 << LK_SHARERS_SHIFT)
 #define	LK_UNLOCKED			LK_SHARERS_LOCK(0)