[Intel-gfx] [PATCH 2/2] drm/i915: fix the racy object accounting

[Daniel Vetter]

Use an atomic_t for the count (since that is useful for leak detection
in tests) and just rip out the object memory check.

v2: Rebase onto the new object create refcount fix patch.

Cc: Chris Wilson <chris at chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_debugfs.c |  5 ++---
 drivers/gpu/drm/i915/i915_drv.h     |  5 ++---
 drivers/gpu/drm/i915/i915_gem.c     | 21 ++++-----------------
 3 files changed, 8 insertions(+), 23 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 9d871c7..67d6699 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -228,9 +228,8 @@ static int i915_gem_object_info(struct seq_file *m, void *data)
 	if (ret)
 		return ret;
 
-	seq_printf(m, "%u objects, %zu bytes\n",
-		   dev_priv->mm.object_count,
-		   dev_priv->mm.object_memory);
+	seq_printf(m, "%u objects\n",
+		   atomic_read(&dev_priv->mm.object_count));
 
 	size = count = mappable_size = mappable_count = 0;
 	count_objects(&dev_priv->mm.bound_list, global_list);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e295561..e5cc6ed 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -925,9 +925,8 @@ struct i915_gem_mm {
 	/* storage for physical objects */
 	struct drm_i915_gem_phys_object *phys_objs[I915_MAX_PHYS_OBJECT];
 
-	/* accounting, useful for userland debugging */
-	size_t object_memory;
-	u32 object_count;
+	/* accounting, useful for leak detection in tests */
+	atomic_t object_count;
 };
 
 struct drm_i915_error_state_buf {
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index dc7e6de..c271c1a 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -71,21 +71,6 @@ static inline void i915_gem_object_fence_lost(struct drm_i915_gem_object *obj)
 	obj->fence_reg = I915_FENCE_REG_NONE;
 }
 
-/* some bookkeeping */
-static void i915_gem_info_add_obj(struct drm_i915_private *dev_priv,
-				  size_t size)
-{
-	dev_priv->mm.object_count++;
-	dev_priv->mm.object_memory += size;
-}
-
-static void i915_gem_info_remove_obj(struct drm_i915_private *dev_priv,
-				     size_t size)
-{
-	dev_priv->mm.object_count--;
-	dev_priv->mm.object_memory -= size;
-}
-
 static int
 i915_gem_wait_for_error(struct i915_gpu_error *error)
 {
@@ -3861,6 +3846,8 @@ unlock:
 void i915_gem_object_init(struct drm_i915_gem_object *obj,
 			  const struct drm_i915_gem_object_ops *ops)
 {
+	struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
+
 	INIT_LIST_HEAD(&obj->mm_list);
 	INIT_LIST_HEAD(&obj->global_list);
 	INIT_LIST_HEAD(&obj->ring_list);
@@ -3874,7 +3861,7 @@ void i915_gem_object_init(struct drm_i915_gem_object *obj,
 	/* Avoid an unnecessary call to unbind on the first bind. */
 	obj->map_and_fenceable = true;
 
-	i915_gem_info_add_obj(obj->base.dev->dev_private, obj->base.size);
+	atomic_inc(&dev_priv->mm.object_count);
 }
 
 static const struct drm_i915_gem_object_ops i915_gem_object_ops = {
@@ -3982,7 +3969,7 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
 		drm_prime_gem_destroy(&obj->base, NULL);
 
 	drm_gem_object_release(&obj->base);
-	i915_gem_info_remove_obj(dev_priv, obj->base.size);
+	atomic_dec(&dev_priv->mm.object_count);
 
 	kfree(obj->bit_17);
 	i915_gem_object_free(obj);
-- 
1.8.1.4