drm/amd/display: Set gamma to NULL at release

Signed-off-by: Yongqiang Sun <yongqiang.sun@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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

@@ -1458,7 +1458,7 @@ void dc_update_surfaces_for_target(struct dc *dc, struct dc_surface_update *upda
 			if (updates[i].gamma &&
 				updates[i].gamma != surface->public.gamma_correction) {
 				if (surface->public.gamma_correction != NULL)
-					dc_gamma_release(surface->public.
+					dc_gamma_release(&surface->public.
 							gamma_correction);
 
 				dc_gamma_retain(updates[i].gamma);

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

@@ -74,8 +74,7 @@ static bool construct(struct dc_context *ctx, struct surface *surface)
 static void destruct(struct surface *surface)
 {
 	if (surface->protected.public.gamma_correction != NULL) {
-		dc_gamma_release(surface->protected.public.gamma_correction);
-		surface->protected.public.gamma_correction = NULL;
+		dc_gamma_release(&surface->protected.public.gamma_correction);
 	}
 	if (surface->protected.public.in_transfer_func != NULL) {
 		dc_transfer_func_release(
@@ -189,15 +188,17 @@ void dc_gamma_retain(const struct dc_gamma *dc_gamma)
 	++gamma->ref_count;
 }
 
-void dc_gamma_release(const struct dc_gamma *dc_gamma)
+void dc_gamma_release(const struct dc_gamma **dc_gamma)
 {
-	struct gamma *gamma = DC_GAMMA_TO_GAMMA(dc_gamma);
+	struct gamma *gamma = DC_GAMMA_TO_GAMMA(*dc_gamma);
 
 	ASSERT(gamma->ref_count > 0);
 	--gamma->ref_count;
 
 	if (gamma->ref_count == 0)
 		dm_free(gamma);
+
+	*dc_gamma = NULL;
 }
 
 struct dc_gamma *dc_create_gamma()

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

@@ -318,7 +318,7 @@ void dc_surface_retain(const struct dc_surface *dc_surface);
 void dc_surface_release(const struct dc_surface *dc_surface);
 
 void dc_gamma_retain(const struct dc_gamma *dc_gamma);
-void dc_gamma_release(const struct dc_gamma *dc_gamma);
+void dc_gamma_release(const struct dc_gamma **dc_gamma);
 struct dc_gamma *dc_create_gamma(void);
 
 void dc_transfer_func_retain(const struct dc_transfer_func *dc_tf);

drivers/gpu/drm/amd/display/modules/color/color.c

@@ -1557,7 +1557,7 @@ void mod_color_destroy(struct mod_color *mod_color)
 
 		for (i = 0; i < core_color->num_sinks; i++)
 			if (core_color->state[i].gamma)
-				dc_gamma_release(core_color->state[i].gamma);
+				dc_gamma_release(&core_color->state[i].gamma);
 
 		dm_free(core_color->state);
 
@@ -1749,8 +1749,7 @@ bool mod_color_remove_sink(struct mod_color *mod_color,
 	for (i = 0; i < core_color->num_sinks; i++) {
 		if (core_color->caps[i].sink == sink) {
 			if (core_color->state[i].gamma) {
-				dc_gamma_release(core_color->state[i].gamma);
-				core_color->state[i].gamma = NULL;
+				dc_gamma_release(&core_color->state[i].gamma);
 			}
 
 			/* To remove this sink, shift everything after down */
@@ -2444,8 +2443,7 @@ bool mod_color_set_input_gamma_correction(struct mod_color *mod_color,
 			if (core_color->state[sink_index].gamma != gamma) {
 				if (core_color->state[sink_index].gamma)
 					dc_gamma_release(
-						core_color->state[sink_index].
-						gamma);
+						&core_color->state[sink_index].gamma);
 
 				dc_gamma_retain(gamma);
 				core_color->state[sink_index].gamma = gamma;