[PATCH v2 5/5] drm/gem: Warn on trying to use a non-existing framebuffer plane

[Thomas Zimmermann <tzimmermann@suse.de>]

Warn if callers of drm_gem_fb_get_obj() try to use a GEM buffer for
a non-existing or unset plane.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Tested-by: Noralf Trønnes <noralf@tronnes.org>
---
 drivers/gpu/drm/drm_gem_framebuffer_helper.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_gem_framebuffer_helper.c b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
index 6d3c26efdeeb..61339a9cd010 100644
--- a/drivers/gpu/drm/drm_gem_framebuffer_helper.c
+++ b/drivers/gpu/drm/drm_gem_framebuffer_helper.c
@@ -53,7 +53,11 @@ MODULE_IMPORT_NS(DMA_BUF);
 struct drm_gem_object *drm_gem_fb_get_obj(struct drm_framebuffer *fb,
 					  unsigned int plane)
 {
-	if (plane >= ARRAY_SIZE(fb->obj))
+	struct drm_device *dev = fb->dev;
+
+	if (drm_WARN_ON_ONCE(dev, plane >= ARRAY_SIZE(fb->obj)))
+		return NULL;
+	else if (drm_WARN_ON_ONCE(dev, !fb->obj[plane]))
 		return NULL;
 
 	return fb->obj[plane];
-- 
2.36.1