drm/nouveau/core: rebase object ref/use counts after ctor/init/fini events

This is intended to support named (with a handle, etc) objects having
children that don't have an outside reference.

This will replace the various hacks around the place where subdev
objects have children, and have to manually drop the self-refs so
that they can be destroyed etc when all the outside refs have gone.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/core/object.c

@@ -136,26 +136,30 @@ nouveau_object_ctor(struct nouveau_object *parent,
 		    struct nouveau_object **pobject)
 {
 	struct nouveau_ofuncs *ofuncs = oclass->ofuncs;
+	struct nouveau_object *object = NULL;
 	int ret;
 
-	*pobject = NULL;
-
-	ret = ofuncs->ctor(parent, engine, oclass, data, size, pobject);
+	ret = ofuncs->ctor(parent, engine, oclass, data, size, &object);
+	*pobject = object;
 	if (ret < 0) {
 		if (ret != -ENODEV) {
 			nv_error(parent, "failed to create 0x%08x, %d\n",
 				 oclass->handle, ret);
 		}
 
-		if (*pobject) {
-			ofuncs->dtor(*pobject);
+		if (object) {
+			ofuncs->dtor(object);
 			*pobject = NULL;
 		}
 
 		return ret;
 	}
 
-	nv_debug(*pobject, "created\n");
+	if (ret == 0) {
+		nv_debug(object, "created\n");
+		atomic_set(&object->refcount, 1);
+	}
+
 	return 0;
 }
 
@@ -327,6 +331,7 @@ nouveau_object_inc(struct nouveau_object *object)
 	}
 
 	ret = nv_ofuncs(object)->init(object);
+	atomic_set(&object->usecount, 1);
 	if (ret) {
 		nv_error(object, "init failed, %d\n", ret);
 		goto fail_self;
@@ -357,6 +362,7 @@ nouveau_object_decf(struct nouveau_object *object)
 	nv_trace(object, "stopping...\n");
 
 	ret = nv_ofuncs(object)->fini(object, false);
+	atomic_set(&object->usecount, 0);
 	if (ret)
 		nv_warn(object, "failed fini, %d\n", ret);
 
@@ -381,6 +387,7 @@ nouveau_object_decs(struct nouveau_object *object)
 	nv_trace(object, "suspending...\n");
 
 	ret = nv_ofuncs(object)->fini(object, true);
+	atomic_set(&object->usecount, 0);
 	if (ret) {
 		nv_error(object, "failed suspend, %d\n", ret);
 		return ret;