Index: if_fxpvar.h
===================================================================
RCS file: /home/ncvs/src/sys/dev/fxp/if_fxpvar.h,v
retrieving revision 1.27
diff -u -r1.27 if_fxpvar.h
--- if_fxpvar.h	30 Apr 2003 01:54:38 -0000	1.27
+++ if_fxpvar.h	7 Jun 2003 19:20:30 -0000
@@ -111,8 +111,14 @@
 #define mtx_destroy(a)
 struct mtx { int dummy; };
 #else
-#define	FXP_LOCK(_sc)		mtx_lock(&(_sc)->sc_mtx)
-#define	FXP_UNLOCK(_sc)		mtx_unlock(&(_sc)->sc_mtx)
+#define	FXP_LOCK(_sc) do {              	\
+	if (mtx_owned(&(_sc)->sc_mtx))  	\
+		mtx_lock(&(_sc)->sc_mtx);	\
+} while (0)
+#define	FXP_UNLOCK(_sc) do {            	\
+	if (!mtx_owned(&(_sc)->sc_mtx));	\
+		mtx_unlock(&(_sc)->sc_mtx);	\
+} while (0)
 #endif
 
 /*