[PATCH 7/7] drm/nouveau: complain loudly if buffer is pinned during destruction

[Maarten Lankhorst]

Shouldn't happen, and we invert the struct_mutex with reservation here,
potentially leading to deadlocks. Once reservations become lockdep annotated,
lockdep will go splat on this.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst at canonical.com>
---
 drivers/gpu/drm/nouveau/nouveau_gem.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_gem.c 
b/drivers/gpu/drm/nouveau/nouveau_gem.c
index b4b4d0c..7054706 100644
--- a/drivers/gpu/drm/nouveau/nouveau_gem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_gem.c
@@ -50,7 +50,8 @@ nouveau_gem_object_del(struct drm_gem_object *gem)
                return;
        nvbo->gem = NULL;

-       if (unlikely(nvbo->pin_refcnt)) {
+       /* Lockdep hates you for doing reserve with gem object lock held */
+       if (WARN_ON_ONCE(nvbo->pin_refcnt)) {
                nvbo->pin_refcnt = 1;
                nouveau_bo_unpin(nvbo);
        }
-- 
1.8.2.2