drm/ttm: check the return value of register_shrinker

This fixes the build warning:
"ignoring return value of 'register_shrinker', declared with
attribute warn_unused_result [-Wunused-result]"
Signed-off-by: Roger He <Hongbo.He@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/ttm/ttm_page_alloc.c

@@ -477,12 +477,12 @@ ttm_pool_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 	return count;
 }
 
-static void ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
+static int ttm_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 {
 	manager->mm_shrink.count_objects = ttm_pool_shrink_count;
 	manager->mm_shrink.scan_objects = ttm_pool_shrink_scan;
 	manager->mm_shrink.seeks = 1;
-	register_shrinker(&manager->mm_shrink);
+	return register_shrinker(&manager->mm_shrink);
 }
 
 static void ttm_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
@@ -1032,15 +1032,18 @@ int ttm_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 
 	ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
 				   &glob->kobj, "pool");
-	if (unlikely(ret != 0)) {
+	if (unlikely(ret != 0))
+		goto error;
+
+	ret = ttm_pool_mm_shrink_init(_manager);
+	if (unlikely(ret != 0))
+		goto error;
+	return 0;
+
+error:
 	kobject_put(&_manager->kobj);
 	_manager = NULL;
 	return ret;
-	}
-
-	ttm_pool_mm_shrink_init(_manager);
-
-	return 0;
 }
 
 void ttm_page_alloc_fini(void)

drivers/gpu/drm/ttm/ttm_page_alloc_dma.c

@@ -1182,12 +1182,12 @@ ttm_dma_pool_shrink_count(struct shrinker *shrink, struct shrink_control *sc)
 	return count;
 }
 
-static void ttm_dma_pool_mm_shrink_init(struct ttm_pool_manager *manager)
+static int ttm_dma_pool_mm_shrink_init(struct ttm_pool_manager *manager)
 {
 	manager->mm_shrink.count_objects = ttm_dma_pool_shrink_count;
 	manager->mm_shrink.scan_objects = &ttm_dma_pool_shrink_scan;
 	manager->mm_shrink.seeks = 1;
-	register_shrinker(&manager->mm_shrink);
+	return register_shrinker(&manager->mm_shrink);
 }
 
 static void ttm_dma_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
@@ -1197,7 +1197,7 @@ static void ttm_dma_pool_mm_shrink_fini(struct ttm_pool_manager *manager)
 
 int ttm_dma_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 {
-	int ret = -ENOMEM;
+	int ret;
 
 	WARN_ON(_manager);
 
@@ -1205,7 +1205,7 @@ int ttm_dma_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 
 	_manager = kzalloc(sizeof(*_manager), GFP_KERNEL);
 	if (!_manager)
-		goto err;
+		return -ENOMEM;
 
 	mutex_init(&_manager->lock);
 	INIT_LIST_HEAD(&_manager->pools);
@@ -1217,13 +1217,17 @@ int ttm_dma_page_alloc_init(struct ttm_mem_global *glob, unsigned max_pages)
 	/* This takes care of auto-freeing the _manager */
 	ret = kobject_init_and_add(&_manager->kobj, &ttm_pool_kobj_type,
 				   &glob->kobj, "dma_pool");
-	if (unlikely(ret != 0)) {
-		kobject_put(&_manager->kobj);
-		goto err;
-	}
-	ttm_dma_pool_mm_shrink_init(_manager);
+	if (unlikely(ret != 0))
+		goto error;
+
+	ret = ttm_dma_pool_mm_shrink_init(_manager);
+	if (unlikely(ret != 0))
+		goto error;
 	return 0;
-err:
+
+error:
+	kobject_put(&_manager->kobj);
+	_manager = NULL;
 	return ret;
 }