From: Dave Airlie <airlied@redhat.com>
Date: Tue, 3 Oct 2017 12:38:59 +1000
Subject: amdgpu/dc: use kref for dc_plane_state.
Git-commit: 4d090f0fae08ddaccf8caaf707f386d52b7f7a08
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

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>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/display/dc/core/dc_surface.c |   20 ++++++++++----------
 drivers/gpu/drm/amd/display/dc/dc.h              |    2 +-
 2 files changed, 11 insertions(+), 11 deletions(-)

--- a/drivers/gpu/drm/amd/display/dc/core/dc_surface.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_surface.c
@@ -71,8 +71,8 @@ struct dc_plane_state *dc_create_plane_s
 	if (NULL == plane_state)
 		return NULL;
 
+	kref_init(&plane_state->refcount);
 	construct(core_dc->ctx, plane_state);
-	atomic_inc(&plane_state->ref_count);
 
 	return plane_state;
 }
@@ -112,19 +112,19 @@ const struct dc_plane_status *dc_plane_g
 
 void dc_plane_state_retain(struct dc_plane_state *plane_state)
 {
-	ASSERT(atomic_read(&plane_state->ref_count) > 0);
-	atomic_inc(&plane_state->ref_count);
+	kref_get(&plane_state->refcount);
 }
 
-void dc_plane_state_release(struct dc_plane_state *plane_state)
+static void dc_plane_state_free(struct kref *kref)
 {
-	ASSERT(atomic_read(&plane_state->ref_count) > 0);
-	atomic_dec(&plane_state->ref_count);
+	struct dc_plane_state *plane_state = container_of(kref, struct dc_plane_state, refcount);
+	destruct(plane_state);
+	kfree(plane_state);
+}
 
-	if (atomic_read(&plane_state->ref_count) == 0) {
-		destruct(plane_state);
-		kfree(plane_state);
-	}
+void dc_plane_state_release(struct dc_plane_state *plane_state)
+{
+	kref_put(&plane_state->refcount, dc_plane_state_free);
 }
 
 void dc_gamma_retain(struct dc_gamma *gamma)
--- a/drivers/gpu/drm/amd/display/dc/dc.h
+++ b/drivers/gpu/drm/amd/display/dc/dc.h
@@ -381,7 +381,7 @@ struct dc_plane_state {
 
 	/* private to dc_surface.c */
 	enum dc_irq_source irq_source;
-	atomic_t ref_count;
+	struct kref refcount;
 };
 
 struct dc_plane_info {