diff --git a/src/libnm-platform/nmp-route-manager.c b/src/libnm-platform/nmp-route-manager.c
index a4cbf2e8bb..6828bb57f9 100644
--- a/src/libnm-platform/nmp-route-manager.c
+++ b/src/libnm-platform/nmp-route-manager.c
@@ -788,12 +788,13 @@ nmp_route_manager_new(NMPlatform *platform)
     return self;
 }
 
-void
+NMPRouteManager *
 nmp_route_manager_ref(NMPRouteManager *self)
 {
-    g_return_if_fail(NMP_IS_ROUTE_MANAGER(self));
+    g_return_val_if_fail(NMP_IS_ROUTE_MANAGER(self), NULL);
 
     self->ref_count++;
+    return self;
 }
 
 void
diff --git a/src/libnm-platform/nmp-route-manager.h b/src/libnm-platform/nmp-route-manager.h
index 17af8ee0c5..23e4c2d341 100644
--- a/src/libnm-platform/nmp-route-manager.h
+++ b/src/libnm-platform/nmp-route-manager.h
@@ -13,8 +13,8 @@ typedef struct _NMPRouteManager NMPRouteManager;
 
 NMPRouteManager *nmp_route_manager_new(NMPlatform *platform);
 
-void nmp_route_manager_ref(NMPRouteManager *self);
-void nmp_route_manager_unref(NMPRouteManager *self);
+NMPRouteManager *nmp_route_manager_ref(NMPRouteManager *self);
+void             nmp_route_manager_unref(NMPRouteManager *self);
 
 #define nm_auto_unref_route_manager nm_auto(_nmp_route_manager_unref)
 NM_AUTO_DEFINE_FCN0(NMPRouteManager *, _nmp_route_manager_unref, nmp_route_manager_unref);