amdgpu/dc: convert dc_sink to kref.

Refcounts use krefs.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/core/dc_sink.c

@@ -63,19 +63,19 @@ static bool construct(struct dc_sink *sink, const struct dc_sink_init_data *init
 
 void dc_sink_retain(struct dc_sink *sink)
 {
-	ASSERT(atomic_read(&sink->ref_count) > 0);
-	atomic_inc(&sink->ref_count);
+	kref_get(&sink->refcount);
 }
 
-void dc_sink_release(struct dc_sink *sink)
+static void dc_sink_free(struct kref *kref)
 {
-	ASSERT(atomic_read(&sink->ref_count) > 0);
-	atomic_dec(&sink->ref_count);
-
-	if (atomic_read(&sink->ref_count) == 0) {
+	struct dc_sink *sink = container_of(kref, struct dc_sink, refcount);
 	destruct(sink);
 	kfree(sink);
-	}
+}
+
+void dc_sink_release(struct dc_sink *sink)
+{
+	kref_put(&sink->refcount, dc_sink_free);
 }
 
 struct dc_sink *dc_sink_create(const struct dc_sink_init_data *init_params)
@@ -88,7 +88,7 @@ struct dc_sink *dc_sink_create(const struct dc_sink_init_data *init_params)
 	if (false == construct(sink, init_params))
 		goto construct_fail;
 
-	atomic_inc(&sink->ref_count);
+	kref_init(&sink->refcount);
 
 	return sink;
 

drivers/gpu/drm/amd/display/dc/dc.h

@@ -971,7 +971,7 @@ struct dc_sink {
 	struct dc_context *ctx;
 
 	/* private to dc_sink.c */
-	atomic_t ref_count;
+	struct kref refcount;
 };
 
 void dc_sink_retain(struct dc_sink *sink);