drm: Compile time enabling for asserts in drm_mm

Use CONFIG_DRM_DEBUG_MM to conditionally enable the internal and
validation checking using BUG_ON. Ideally these paths should all be
exercised by CI selftests (with the asserts enabled).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-4-chris@chris-wilson.co.uk
Link: http://patchwork.freedesktop.org/patch/msgid/20161222083641.2691-4-chris@chris-wilson.co.uk

1 files changed, 7 insertions, 1 deletions

diff --git a/include/drm/drm_mm.h b/include/drm/drm_mm.h
index f6a68ed5ecaf..525543019896 100644
--- a/include/drm/drm_mm.h
+++ b/include/drm/drm_mm.h
@@ -48,6 +48,12 @@
 #include <linux/stackdepot.h>
 #endif
 
+#ifdef CONFIG_DRM_DEBUG_MM
+#define DRM_MM_BUG_ON(expr) BUG_ON(expr)
+#else
+#define DRM_MM_BUG_ON(expr) BUILD_BUG_ON_INVALID(expr)
+#endif
+
 enum drm_mm_search_flags {
         DRM_MM_SEARCH_DEFAULT =         0,
         DRM_MM_SEARCH_BEST =            1 << 0,
@@ -155,7 +161,7 @@ static inline u64 __drm_mm_hole_node_start(const struct drm_mm_node *hole_node)
  */
 static inline u64 drm_mm_hole_node_start(const struct drm_mm_node *hole_node)
 {
-        BUG_ON(!hole_node->hole_follows);
+        DRM_MM_BUG_ON(!hole_node->hole_follows);
         return __drm_mm_hole_node_start(hole_node);
 }