drm: modify drm_global_item_ref to avoid two times of writing ref->object

In previous drm_global_item_ref, there are two times of writing
ref->object if item->refcount is 0. So this patch does a minor update
to put alloc and init ref firstly, and then to modify the item of glob
array. Use "else" to avoid two times of writing ref->object. It can
make the code logic more clearly.

Reviewed-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/drm_global.c b/drivers/gpu/drm/drm_global.c
index 3d2e91c4d78e1c1003ac9521250dc4ca41c9b6ae..b404287abb976745c9a4eb8a927f59c473ddd084 100644 (file)
--- a/drivers/gpu/drm/drm_global.c
+++ b/drivers/gpu/drm/drm_global.c
@@ -65,30 +65,34 @@ void drm_global_release(void)
 
 int drm_global_item_ref(struct drm_global_reference *ref)
 {
-       int ret;
+       int ret = 0;
        struct drm_global_item *item = &glob[ref->global_type];
 
        mutex_lock(&item->mutex);
        if (item->refcount == 0) {
-               item->object = kzalloc(ref->size, GFP_KERNEL);
-               if (unlikely(item->object == NULL)) {
+               ref->object = kzalloc(ref->size, GFP_KERNEL);
+               if (unlikely(ref->object == NULL)) {
                        ret = -ENOMEM;
-                       goto out_err;
+                       goto error_unlock;
                }
-
-               ref->object = item->object;
                ret = ref->init(ref);
                if (unlikely(ret != 0))
-                       goto out_err;
+                       goto error_free;
 
+               item->object = ref->object;
+       } else {
+               ref->object = item->object;
        }
+
        ++item->refcount;
-       ref->object = item->object;
        mutex_unlock(&item->mutex);
        return 0;
-out_err:
+
+error_free:
+       kfree(ref->object);
+       ref->object = NULL;
+error_unlock:
        mutex_unlock(&item->mutex);
-       item->object = NULL;
        return ret;
 }
 EXPORT_SYMBOL(drm_global_item_ref);