[Intel-gfx] [PATCH 12/12] drm/i915: Add BKL asserts to get page helpers

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Purpose is catching illegal callers.

v2: Replace WARN_ON with lockdep_assert_held. (Chris Wilson, Daniel Vetter)
v3: Moved under dedicated CONFIG_DRM_I915_DEBUG and back to WARN_ON.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_drv.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 4ad025210416..6d34f74a5919 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2933,6 +2933,9 @@ i915_gem_object_get_dirty_page(struct drm_i915_gem_object *obj, int n);
 static inline struct page *
 i915_gem_object_get_page(struct drm_i915_gem_object *obj, int n)
 {
+#ifdef CONFIG_DRM_I915_DEBUG
+	WARN_ON_ONCE(!mutex_is_locked(&obj->base.dev->struct_mutex));
+#endif
 	if (WARN_ON(n >= obj->base.size >> PAGE_SHIFT))
 		return NULL;
 
-- 
1.9.1