Index: head/sys/geom/geom_ctl.h
===================================================================
--- head/sys/geom/geom_ctl.h
+++ head/sys/geom/geom_ctl.h
@@ -78,7 +78,8 @@
 
 #define GEOM_CTL	_IOW('G', GCTL_VERSION, struct gctl_req)
 
-#define PATH_GEOM_CTL	"geom.ctl"
+#define GEOM_CTL_ARG_MAX 2048	/* maximum number of parameters */
 
+#define PATH_GEOM_CTL	"geom.ctl"
 
 #endif /* _GEOM_GEOM_CTL_H_ */
Index: head/sys/geom/geom_ctl.c
===================================================================
--- head/sys/geom/geom_ctl.c
+++ head/sys/geom/geom_ctl.c
@@ -139,7 +139,7 @@
 	char *p;
 	u_int i;
 
-	if (req->narg > 2048) {
+	if (req->narg > GEOM_CTL_ARG_MAX) {
 		gctl_error(req, "too many arguments");
 		req->arg = NULL;
 		return;