[PATCH 4/4] drm: exynos: Keep a reference to frame buffer GEM objects

[Laurent Pinchart]

GEM objects used by frame buffers must be referenced for the whole life
of the frame buffer. Release the references in the frame buffer
destructor instead of its constructor.

Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 drivers/gpu/drm/exynos/exynos_drm_fb.c |   19 ++++++++++++++-----
 1 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_fb.c b/drivers/gpu/drm/exynos/exynos_drm_fb.c
index f82a299..4ccfe43 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_fb.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_fb.c
@@ -51,11 +51,22 @@ struct exynos_drm_fb {
 static void exynos_drm_fb_destroy(struct drm_framebuffer *fb)
 {
 	struct exynos_drm_fb *exynos_fb = to_exynos_fb(fb);
+	unsigned int i;
 
 	DRM_DEBUG_KMS("%s\n", __FILE__);
 
 	drm_framebuffer_cleanup(fb);
 
+	for (i = 0; i < ARRAY_SIZE(exynos_fb->exynos_gem_obj); i++) {
+		struct drm_gem_object *obj;
+
+		if (exynos_fb->exynos_gem_obj[i] == NULL)
+			continue;
+
+		obj = &exynos_fb->exynos_gem_obj[i]->base;
+		drm_gem_object_unreference_unlocked(obj);
+	}
+
 	kfree(exynos_fb);
 	exynos_fb = NULL;
 }
@@ -134,11 +145,11 @@ exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 		return ERR_PTR(-ENOENT);
 	}
 
-	drm_gem_object_unreference_unlocked(obj);
-
 	fb = exynos_drm_framebuffer_init(dev, mode_cmd, obj);
-	if (IS_ERR(fb))
+	if (IS_ERR(fb)) {
+		drm_gem_object_unreference_unlocked(obj);
 		return fb;
+	}
 
 	exynos_fb = to_exynos_fb(fb);
 	nr = exynos_drm_format_num_buffers(fb->pixel_format);
@@ -152,8 +163,6 @@ exynos_user_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 			return ERR_PTR(-ENOENT);
 		}
 
-		drm_gem_object_unreference_unlocked(obj);
-
 		exynos_fb->exynos_gem_obj[i] = to_exynos_gem_obj(obj);
 	}
 
-- 
1.7.3.4