Fence object reference / dereference cleanup.

Buffer object dereference cleanup.
Add a struct drm_device member to fence objects:
This can simplify code, particularly in drivers.

5 files changed, 134 insertions, 127 deletions

diff --git a/linux-core/drm_bo.c b/linux-core/drm_bo.c
index f1ca0b44..ab257825 100644
--- a/linux-core/drm_bo.c
+++ b/linux-core/drm_bo.c
@@ -269,31 +269,25 @@ static int drm_bo_handle_move_mem(drm_buffer_object_t * bo,
 int drm_bo_wait(drm_buffer_object_t * bo, int lazy, int ignore_signals,
 		int no_wait)
 {
-
-	drm_fence_object_t *fence = bo->fence;
 	int ret;
 
 	DRM_ASSERT_LOCKED(&bo->mutex);
 
-	if (fence) {
-		drm_device_t *dev = bo->dev;
-		if (drm_fence_object_signaled(dev, fence, bo->fence_type, 0)) {
-			drm_fence_usage_deref_unlocked(dev, fence);
-			bo->fence = NULL;
+	if (bo->fence) {
+		if (drm_fence_object_signaled(bo->fence, bo->fence_type, 0)) {
+			drm_fence_usage_deref_unlocked(&bo->fence);
 			return 0;
 		}
 		if (no_wait) {
 			return -EBUSY;
 		}
 		ret =
-		    drm_fence_object_wait(dev, fence, lazy, ignore_signals,
+		    drm_fence_object_wait(bo->fence, lazy, ignore_signals,
 					  bo->fence_type);
 		if (ret)
 			return ret;
 
-		drm_fence_usage_deref_unlocked(dev, fence);
-		bo->fence = NULL;
-
+		drm_fence_usage_deref_unlocked(&bo->fence);
 	}
 	return 0;
 }
@@ -321,10 +315,8 @@ static int drm_bo_expire_fence(drm_buffer_object_t * bo, int allow_errors)
 					  "Evicting buffer.\n");
 			}
 		}
-		if (bo->fence) {
-			drm_fence_usage_deref_unlocked(dev, bo->fence);
-			bo->fence = NULL;
-		}
+		if (bo->fence)
+			drm_fence_usage_deref_unlocked(&bo->fence);
 	}
 	return 0;
 }
@@ -348,11 +340,9 @@ static void drm_bo_cleanup_refs(drm_buffer_object_t * bo, int remove_all)
 
 	DRM_FLAG_MASKED(bo->priv_flags, 0, _DRM_BO_FLAG_UNFENCED);
 
-	if (bo->fence && drm_fence_object_signaled(dev, bo->fence, 
-						   bo->fence_type, 0)) {
-		drm_fence_usage_deref_unlocked(dev, bo->fence);
-		bo->fence = NULL;
-	}
+	if (bo->fence && drm_fence_object_signaled(bo->fence,
+						   bo->fence_type, 0))
+		drm_fence_usage_deref_unlocked(&bo->fence);
 
 	if (bo->fence && remove_all)
 		(void)drm_bo_expire_fence(bo, 0);
@@ -383,7 +373,7 @@ static void drm_bo_cleanup_refs(drm_buffer_object_t * bo, int remove_all)
 	}
 
 	if (list_empty(&bo->ddestroy)) {
-		drm_fence_object_flush(dev, bo->fence, bo->fence_type);
+		drm_fence_object_flush(bo->fence, bo->fence_type);
 		list_add_tail(&bo->ddestroy, &bm->ddestroy);
 		schedule_delayed_work(&bm->wq,
 				      ((DRM_HZ / 100) < 1) ? 1 : DRM_HZ / 100);
@@ -503,12 +493,15 @@ static void drm_bo_delayed_workqueue(struct work_struct *work)
 	mutex_unlock(&dev->struct_mutex);
 }
 
-void drm_bo_usage_deref_locked(drm_buffer_object_t * bo)
+void drm_bo_usage_deref_locked(drm_buffer_object_t ** bo)
 {
-	DRM_ASSERT_LOCKED(&bo->dev->struct_mutex);
+        struct drm_buffer_object *tmp_bo = *bo;
+	bo = NULL;
 
-	if (atomic_dec_and_test(&bo->usage)) {
-		drm_bo_destroy_locked(bo);
+	DRM_ASSERT_LOCKED(&tmp_bo->dev->struct_mutex);
+
+	if (atomic_dec_and_test(&tmp_bo->usage)) {
+		drm_bo_destroy_locked(tmp_bo);
 	}
 }
 
@@ -520,17 +513,19 @@ static void drm_bo_base_deref_locked(drm_file_t * priv, drm_user_object_t * uo)
 	DRM_ASSERT_LOCKED(&bo->dev->struct_mutex);
 
 	drm_bo_takedown_vm_locked(bo);
-	drm_bo_usage_deref_locked(bo);
+	drm_bo_usage_deref_locked(&bo);
 }
 
-static void drm_bo_usage_deref_unlocked(drm_buffer_object_t * bo)
+static void drm_bo_usage_deref_unlocked(drm_buffer_object_t ** bo)
 {
-	drm_device_t *dev = bo->dev;
+	struct drm_buffer_object *tmp_bo = *bo;
+	drm_device_t *dev = tmp_bo->dev;
 
-	if (atomic_dec_and_test(&bo->usage)) {
+	*bo = NULL;
+	if (atomic_dec_and_test(&tmp_bo->usage)) {
 		mutex_lock(&dev->struct_mutex);
-		if (atomic_read(&bo->usage) == 0)
-			drm_bo_destroy_locked(bo);
+		if (atomic_read(&tmp_bo->usage) == 0)
+			drm_bo_destroy_locked(tmp_bo);
 		mutex_unlock(&dev->struct_mutex);
 	}
 }
@@ -616,16 +611,15 @@ int drm_fence_buffer_objects(drm_file_t * priv,
 		if (entry->priv_flags & _DRM_BO_FLAG_UNFENCED) {
 			count++;
 			if (entry->fence)
-				drm_fence_usage_deref_locked(dev, entry->fence);
-			entry->fence = fence;
-			atomic_inc(&fence->usage);
+				drm_fence_usage_deref_locked(&entry->fence);
+			entry->fence = drm_fence_reference_locked(fence);
 			DRM_FLAG_MASKED(entry->priv_flags, 0,
 					_DRM_BO_FLAG_UNFENCED);
 			DRM_WAKEUP(&entry->event_queue);
 			drm_bo_add_to_lru(entry);
 		}
 		mutex_unlock(&entry->mutex);
-		drm_bo_usage_deref_locked(entry);
+		drm_bo_usage_deref_locked(&entry);
 		l = f_list.next;
 	}
 	DRM_DEBUG("Fenced %d buffers\n", count);
@@ -742,7 +736,7 @@ static int drm_bo_mem_force_space(drm_device_t * dev,
 
 		ret = drm_bo_evict(entry, mem_type, no_wait);
 		mutex_unlock(&entry->mutex);
-		drm_bo_usage_deref_unlocked(entry);
+		drm_bo_usage_deref_unlocked(&entry);
 		if (ret)
 			return ret;
 		mutex_lock(&dev->struct_mutex);
@@ -962,10 +956,8 @@ static int drm_bo_quick_busy(drm_buffer_object_t * bo)
 
 	BUG_ON(bo->priv_flags & _DRM_BO_FLAG_UNFENCED);
 	if (fence) {
-		drm_device_t *dev = bo->dev;
-		if (drm_fence_object_signaled(dev, fence, bo->fence_type, 0)) {
-			drm_fence_usage_deref_unlocked(dev, fence);
-			bo->fence = NULL;
+		if (drm_fence_object_signaled(fence, bo->fence_type, 0)) {
+			drm_fence_usage_deref_unlocked(&bo->fence);
 			return 0;
 		}
 		return 1;
@@ -984,16 +976,13 @@ static int drm_bo_busy(drm_buffer_object_t * bo)
 
 	BUG_ON(bo->priv_flags & _DRM_BO_FLAG_UNFENCED);
 	if (fence) {
-		drm_device_t *dev = bo->dev;
-		if (drm_fence_object_signaled(dev, fence, bo->fence_type, 0)) {
-			drm_fence_usage_deref_unlocked(dev, fence);
-			bo->fence = NULL;
+		if (drm_fence_object_signaled(fence, bo->fence_type, 0)) {
+			drm_fence_usage_deref_unlocked(&bo->fence);
 			return 0;
 		}
-		drm_fence_object_flush(dev, fence, DRM_FENCE_TYPE_EXE);
-		if (drm_fence_object_signaled(dev, fence, bo->fence_type, 0)) {
-			drm_fence_usage_deref_unlocked(dev, fence);
-			bo->fence = NULL;
+		drm_fence_object_flush(fence, DRM_FENCE_TYPE_EXE);
+		if (drm_fence_object_signaled(fence, bo->fence_type, 0)) {
+			drm_fence_usage_deref_unlocked(&bo->fence);
 			return 0;
 		}
 		return 1;
@@ -1190,7 +1179,7 @@ static int drm_buffer_object_map(drm_file_t * priv, uint32_t handle,
 		drm_bo_fill_rep_arg(bo, rep);
       out:
 	mutex_unlock(&bo->mutex);
-	drm_bo_usage_deref_unlocked(bo);
+	drm_bo_usage_deref_unlocked(&bo);
 	return ret;
 }
 
@@ -1216,7 +1205,7 @@ static int drm_buffer_object_unmap(drm_file_t * priv, uint32_t handle)
 	}
 
 	drm_remove_ref_object(priv, ro);
-	drm_bo_usage_deref_locked(bo);
+	drm_bo_usage_deref_locked(&bo);
       out:
 	mutex_unlock(&dev->struct_mutex);
 	return ret;
@@ -1512,7 +1501,7 @@ static int drm_bo_handle_validate(drm_file_t * priv, uint32_t handle,
 
 	mutex_unlock(&bo->mutex);
 
-	drm_bo_usage_deref_unlocked(bo);
+	drm_bo_usage_deref_unlocked(&bo);
 	return ret;
 }
 
@@ -1534,7 +1523,7 @@ static int drm_bo_handle_info(drm_file_t * priv, uint32_t handle,
 		(void)drm_bo_busy(bo);
 	drm_bo_fill_rep_arg(bo, rep);
 	mutex_unlock(&bo->mutex);
-	drm_bo_usage_deref_unlocked(bo);
+	drm_bo_usage_deref_unlocked(&bo);
 	return 0;
 }
 
@@ -1566,7 +1555,7 @@ static int drm_bo_handle_wait(drm_file_t * priv, uint32_t handle,
 
       out:
 	mutex_unlock(&bo->mutex);
-	drm_bo_usage_deref_unlocked(bo);
+	drm_bo_usage_deref_unlocked(&bo);
 	return ret;
 }
 
@@ -1651,7 +1640,7 @@ int drm_buffer_object_create(drm_device_t *dev,
       out_err:
 	mutex_unlock(&bo->mutex);
 
-	drm_bo_usage_deref_unlocked(bo);
+	drm_bo_usage_deref_unlocked(&bo);
 	return ret;
 }
 
@@ -1728,7 +1717,7 @@ int drm_bo_ioctl(DRM_IOCTL_ARGS)
 						   mask &
 						   DRM_BO_FLAG_SHAREABLE);
 			if (rep.ret)
-				drm_bo_usage_deref_unlocked(entry);
+				drm_bo_usage_deref_unlocked(&entry);
 
 			if (rep.ret)
 				break;
@@ -1957,7 +1946,7 @@ restart:
 					allow_errors);
 		mutex_lock(&dev->struct_mutex);
 
-		drm_bo_usage_deref_locked(entry);
+		drm_bo_usage_deref_locked(&entry);
 		if (ret)
 			return ret;
 
@@ -1967,10 +1956,8 @@ restart:
 
 		do_restart = ((next->prev != list) && (next->prev != prev));
 
-		if (nentry != NULL && do_restart) {
-			drm_bo_usage_deref_locked(nentry);
-			nentry = NULL;
-		}
+		if (nentry != NULL && do_restart)
+			drm_bo_usage_deref_locked(&nentry);
 
 		if (do_restart)
 			goto restart;
@@ -2365,7 +2352,7 @@ static void drm_bo_takedown_vm_locked(drm_buffer_object_t * bo)
 	drm_ctl_free(map, sizeof(*map), DRM_MEM_BUFOBJ);
 	list->map = NULL;
 	list->user_token = 0ULL;
-	drm_bo_usage_deref_locked(bo);
+	drm_bo_usage_deref_locked(&bo);
 }
 
 static int drm_bo_setup_vm_locked(drm_buffer_object_t * bo)
diff --git a/linux-core/drm_bo_move.c b/linux-core/drm_bo_move.c
index 4f752065..8ef2a8ff 100644
--- a/linux-core/drm_bo_move.c
+++ b/linux-core/drm_bo_move.c
@@ -306,7 +306,7 @@ int drm_buffer_object_transfer(drm_buffer_object_t * bo,
 	INIT_LIST_HEAD(&fbo->p_mm_list);
 #endif
 
-	atomic_inc(&bo->fence->usage);
+	drm_fence_reference_unlocked(&fbo->fence, bo->fence);
 	fbo->pinned_node = NULL;
 	fbo->mem.mm_node->private = (void *)fbo;
 	atomic_set(&fbo->usage, 1);
@@ -339,7 +339,7 @@ int drm_bo_move_accel_cleanup(drm_buffer_object_t * bo,
 	drm_buffer_object_t *old_obj;
 
 	if (bo->fence)
-		drm_fence_usage_deref_unlocked(dev, bo->fence);
+		drm_fence_usage_deref_unlocked(&bo->fence);
 	ret = drm_fence_object_create(dev, fence_class, fence_type,
 				      fence_flags | DRM_FENCE_FLAG_EMIT,
 				      &bo->fence);
@@ -396,7 +396,7 @@ int drm_bo_move_accel_cleanup(drm_buffer_object_t * bo,
 		DRM_FLAG_MASKED(bo->priv_flags, 0, _DRM_BO_FLAG_UNFENCED);
 		drm_bo_add_to_lru(old_obj);
 
-		drm_bo_usage_deref_locked(old_obj);
+		drm_bo_usage_deref_locked(&old_obj);
 		mutex_unlock(&dev->struct_mutex);
 
 	}
diff --git a/linux-core/drm_fence.c b/linux-core/drm_fence.c
index b5fc2235..ace70d51 100644
--- a/linux-core/drm_fence.c
+++ b/linux-core/drm_fence.c
@@ -124,56 +124,76 @@ static void drm_fence_unring(drm_device_t * dev, struct list_head *ring)
 	write_unlock_irqrestore(&fm->lock, flags);
 }
 
-void drm_fence_usage_deref_locked(drm_device_t * dev,
-				  drm_fence_object_t * fence)
+void drm_fence_usage_deref_locked(drm_fence_object_t ** fence)
 {
+	struct drm_fence_object *tmp_fence = *fence;
+	struct drm_device *dev = tmp_fence->dev;
 	drm_fence_manager_t *fm = &dev->fm;
 
 	DRM_ASSERT_LOCKED(&dev->struct_mutex);
-
-	if (atomic_dec_and_test(&fence->usage)) {
-		drm_fence_unring(dev, &fence->ring);
+	*fence = NULL;
+	if (atomic_dec_and_test(&tmp_fence->usage)) {
+		drm_fence_unring(dev, &tmp_fence->ring);
 		DRM_DEBUG("Destroyed a fence object 0x%08lx\n",
-			  fence->base.hash.key);
+			  tmp_fence->base.hash.key);
 		atomic_dec(&fm->count);
-		BUG_ON(!list_empty(&fence->base.list));
-		drm_ctl_free(fence, sizeof(*fence), DRM_MEM_FENCE);
+		BUG_ON(!list_empty(&tmp_fence->base.list));
+		drm_ctl_free(tmp_fence, sizeof(*tmp_fence), DRM_MEM_FENCE);
 	}
 }
 
-void drm_fence_usage_deref_unlocked(drm_device_t * dev,
-				    drm_fence_object_t * fence)
+void drm_fence_usage_deref_unlocked(drm_fence_object_t ** fence)
 {
+	struct drm_fence_object *tmp_fence = *fence;
+	struct drm_device *dev = tmp_fence->dev;
 	drm_fence_manager_t *fm = &dev->fm;
 
-	if (atomic_dec_and_test(&fence->usage)) {
+	*fence = NULL;
+	if (atomic_dec_and_test(&tmp_fence->usage)) {
 		mutex_lock(&dev->struct_mutex);
-		if (atomic_read(&fence->usage) == 0) {
-			drm_fence_unring(dev, &fence->ring);
+		if (atomic_read(&tmp_fence->usage) == 0) {
+			drm_fence_unring(dev, &tmp_fence->ring);
 			atomic_dec(&fm->count);
-			BUG_ON(!list_empty(&fence->base.list));
-			drm_ctl_free(fence, sizeof(*fence), DRM_MEM_FENCE);
+			BUG_ON(!list_empty(&tmp_fence->base.list));
+			drm_ctl_free(tmp_fence, sizeof(*tmp_fence), DRM_MEM_FENCE);
 		}
 		mutex_unlock(&dev->struct_mutex);
 	}
 }
 
-static void drm_fence_object_destroy(drm_file_t * priv,
-				     drm_user_object_t * base)
+struct drm_fence_object
+*drm_fence_reference_locked(struct drm_fence_object *src)
+{
+	DRM_ASSERT_LOCKED(&src->dev->struct_mutex);
+
+	atomic_inc(&src->usage);
+	return src;
+}
+
+void drm_fence_reference_unlocked(struct drm_fence_object **dst,
+				  struct drm_fence_object *src)
+{
+	mutex_lock(&src->dev->struct_mutex);
+	*dst = src;
+	atomic_inc(&src->usage);
+	mutex_unlock(&src->dev->struct_mutex);
+}
+
+
+static void drm_fence_object_destroy(drm_file_t *priv, drm_user_object_t * base)
 {
-	drm_device_t *dev = priv->head->dev;
 	drm_fence_object_t *fence =
 	    drm_user_object_entry(base, drm_fence_object_t, base);
 
-	drm_fence_usage_deref_locked(dev, fence);
+	drm_fence_usage_deref_locked(&fence);
 }
 
-int drm_fence_object_signaled(drm_device_t * dev,
-			  drm_fence_object_t * fence,
-			  uint32_t mask, int poke_flush)
+int drm_fence_object_signaled(drm_fence_object_t * fence,
+			      uint32_t mask, int poke_flush)
 {
 	unsigned long flags;
 	int signaled;
+	struct drm_device *dev = fence->dev;
 	drm_fence_manager_t *fm = &dev->fm;
 	drm_fence_driver_t *driver = dev->driver->fence_driver;
 
@@ -204,10 +224,10 @@ static void drm_fence_flush_exe(drm_fence_class_manager_t * fc,
 	}
 }
 
-int drm_fence_object_flush(drm_device_t * dev,
-			   drm_fence_object_t * fence,
+int drm_fence_object_flush(drm_fence_object_t * fence,
 			   uint32_t type)
 {
+	struct drm_device *dev = fence->dev;
 	drm_fence_manager_t *fm = &dev->fm;
 	drm_fence_class_manager_t *fc = &fm->class[fence->class];
 	drm_fence_driver_t *driver = dev->driver->fence_driver;
@@ -270,24 +290,23 @@ void drm_fence_flush_old(drm_device_t * dev, uint32_t class, uint32_t sequence)
 		mutex_unlock(&dev->struct_mutex);
 		return;
 	}
-	fence = list_entry(fc->ring.next, drm_fence_object_t, ring);
-	atomic_inc(&fence->usage);
+	fence = drm_fence_reference_locked(list_entry(fc->ring.next, drm_fence_object_t, ring));
 	mutex_unlock(&dev->struct_mutex);
 	diff = (old_sequence - fence->sequence) & driver->sequence_mask;
 	read_unlock_irqrestore(&fm->lock, flags);
 	if (diff < driver->wrap_diff) {
-		drm_fence_object_flush(dev, fence, fence->type);
+		drm_fence_object_flush(fence, fence->type);
 	}
-	drm_fence_usage_deref_unlocked(dev, fence);
+	drm_fence_usage_deref_unlocked(&fence);
 }
 
 EXPORT_SYMBOL(drm_fence_flush_old);
 
-static int drm_fence_lazy_wait(drm_device_t *dev,
-			       drm_fence_object_t *fence,
+static int drm_fence_lazy_wait(drm_fence_object_t *fence,
 			       int ignore_signals,
 			       uint32_t mask)
 {
+	struct drm_device *dev = fence->dev;
 	drm_fence_manager_t *fm = &dev->fm;
 	drm_fence_class_manager_t *fc = &fm->class[fence->class];
 	int signaled;
@@ -296,13 +315,13 @@ static int drm_fence_lazy_wait(drm_device_t *dev,
 
 	do {
 		DRM_WAIT_ON(ret, fc->fence_queue, 3 * DRM_HZ,
-			    (signaled = drm_fence_object_signaled(dev, fence, mask, 1)));
+			    (signaled = drm_fence_object_signaled(fence, mask, 1)));
 		if (signaled)
 			return 0;
 		if (time_after_eq(jiffies, _end))
 			break;
 	} while (ret == -EINTR && ignore_signals);
-	if (drm_fence_object_signaled(dev, fence, mask, 0))
+	if (drm_fence_object_signaled(fence, mask, 0))
 		return 0;
 	if (time_after_eq(jiffies, _end))
 		ret = -EBUSY;
@@ -317,10 +336,10 @@ static int drm_fence_lazy_wait(drm_device_t *dev,
 	return 0;
 }
 
-int drm_fence_object_wait(drm_device_t * dev,
-			  drm_fence_object_t * fence,
+int drm_fence_object_wait(drm_fence_object_t * fence,
 			  int lazy, int ignore_signals, uint32_t mask)
 {
+	struct drm_device *dev = fence->dev;
 	drm_fence_driver_t *driver = dev->driver->fence_driver;
 	int ret = 0;
 	unsigned long _end;
@@ -332,16 +351,16 @@ int drm_fence_object_wait(drm_device_t * dev,
 		return -EINVAL;
 	}
 
-	if (drm_fence_object_signaled(dev, fence, mask, 0))
+	if (drm_fence_object_signaled(fence, mask, 0))
 		return 0;
 
 	_end = jiffies + 3 * DRM_HZ;
 
-	drm_fence_object_flush(dev, fence, mask);
+	drm_fence_object_flush(fence, mask);
 
 	if (lazy && driver->lazy_capable) {
 
-		ret = drm_fence_lazy_wait(dev, fence, ignore_signals, mask);
+		ret = drm_fence_lazy_wait(fence, ignore_signals, mask);
 		if (ret)
 			return ret;
 
@@ -349,7 +368,7 @@ int drm_fence_object_wait(drm_device_t * dev,
 
 		if (driver->has_irq(dev, fence->class,
 				    DRM_FENCE_TYPE_EXE)) {
-			ret = drm_fence_lazy_wait(dev, fence, ignore_signals,
+			ret = drm_fence_lazy_wait(fence, ignore_signals,
 						  DRM_FENCE_TYPE_EXE);
 			if (ret)
 				return ret;
@@ -357,13 +376,13 @@ int drm_fence_object_wait(drm_device_t * dev,
 
 		if (driver->has_irq(dev, fence->class,
 				    mask & ~DRM_FENCE_TYPE_EXE)) {
-			ret = drm_fence_lazy_wait(dev, fence, ignore_signals,
+			ret = drm_fence_lazy_wait(fence, ignore_signals,
 						  mask);
 			if (ret)
 				return ret;
 		}
 	}
-	if (drm_fence_object_signaled(dev, fence, mask, 0))
+	if (drm_fence_object_signaled(fence, mask, 0))
 		return 0;
 
 	/*
@@ -375,7 +394,7 @@ int drm_fence_object_wait(drm_device_t * dev,
 #endif
 	do {
 		schedule();
-		signaled = drm_fence_object_signaled(dev, fence, mask, 1);
+		signaled = drm_fence_object_signaled(fence, mask, 1);
 	} while (!signaled && !time_after_eq(jiffies, _end));
 
 	if (!signaled)
@@ -384,9 +403,10 @@ int drm_fence_object_wait(drm_device_t * dev,
 	return 0;
 }
 
-int drm_fence_object_emit(drm_device_t * dev, drm_fence_object_t * fence,
+int drm_fence_object_emit(drm_fence_object_t * fence,
 			  uint32_t fence_flags, uint32_t class, uint32_t type)
 {
+	struct drm_device *dev = fence->dev;
 	drm_fence_manager_t *fm = &dev->fm;
 	drm_fence_driver_t *driver = dev->driver->fence_driver;
 	drm_fence_class_manager_t *fc = &fm->class[fence->class];
@@ -436,9 +456,10 @@ static int drm_fence_object_init(drm_device_t * dev, uint32_t class,
 	fence->submitted_flush = 0;
 	fence->signaled = 0;
 	fence->sequence = 0;
+	fence->dev = dev;
 	write_unlock_irqrestore(&fm->lock, flags);
 	if (fence_flags & DRM_FENCE_FLAG_EMIT) {
-		ret = drm_fence_object_emit(dev, fence, fence_flags,
+		ret = drm_fence_object_emit(fence, fence_flags,
 					    fence->class, type);
 	}
 	return ret;
@@ -476,7 +497,7 @@ int drm_fence_object_create(drm_device_t * dev, uint32_t class, uint32_t type,
 		return -ENOMEM;
 	ret = drm_fence_object_init(dev, class, type, flags, fence);
 	if (ret) {
-		drm_fence_usage_deref_unlocked(dev, fence);
+		drm_fence_usage_deref_unlocked(&fence);
 		return ret;
 	}
 	*c_fence = fence;
@@ -533,8 +554,7 @@ drm_fence_object_t *drm_lookup_fence_object(drm_file_t * priv, uint32_t handle)
 		mutex_unlock(&dev->struct_mutex);
 		return NULL;
 	}
-	fence = drm_user_object_entry(uo, drm_fence_object_t, base);
-	atomic_inc(&fence->usage);
+	fence = drm_fence_reference_locked(drm_user_object_entry(uo, drm_fence_object_t, base));
 	mutex_unlock(&dev->struct_mutex);
 	return fence;
 }
@@ -568,7 +588,7 @@ int drm_fence_ioctl(DRM_IOCTL_ARGS)
 						arg.flags &
 						DRM_FENCE_FLAG_SHAREABLE);
 		if (ret) {
-			drm_fence_usage_deref_unlocked(dev, fence);
+			drm_fence_usage_deref_unlocked(&fence);
 			return ret;
 		}
 		arg.handle = fence->base.hash.key;
@@ -603,14 +623,14 @@ int drm_fence_ioctl(DRM_IOCTL_ARGS)
 		fence = drm_lookup_fence_object(priv, arg.handle);
 		if (!fence)
 			return -EINVAL;
-		ret = drm_fence_object_flush(dev, fence, arg.type);
+		ret = drm_fence_object_flush(fence, arg.type);
 		break;
 	case drm_fence_wait:
 		fence = drm_lookup_fence_object(priv, arg.handle);
 		if (!fence)
 			return -EINVAL;
 		ret =
-		    drm_fence_object_wait(dev, fence,
+		    drm_fence_object_wait(fence,
 					  arg.flags & DRM_FENCE_FLAG_WAIT_LAZY,
 					  0, arg.type);
 		break;
@@ -619,7 +639,7 @@ int drm_fence_ioctl(DRM_IOCTL_ARGS)
 		fence = drm_lookup_fence_object(priv, arg.handle);
 		if (!fence)
 			return -EINVAL;
-		ret = drm_fence_object_emit(dev, fence, arg.flags, arg.class,
+		ret = drm_fence_object_emit(fence, arg.flags, arg.class,
 					    arg.type);
 		break;
 	case drm_fence_buffers:
@@ -647,7 +667,7 @@ int drm_fence_ioctl(DRM_IOCTL_ARGS)
 	arg.type = fence->type;
 	arg.signaled = fence->signaled;
 	read_unlock_irqrestore(&fm->lock, flags);
-	drm_fence_usage_deref_unlocked(dev, fence);
+	drm_fence_usage_deref_unlocked(&fence);
 
 	DRM_COPY_TO_USER_IOCTL((void __user *)data, arg, sizeof(arg));
 	return ret;
diff --git a/linux-core/drm_objects.h b/linux-core/drm_objects.h
index 59c8902d..f82d6628 100644
--- a/linux-core/drm_objects.h
+++ b/linux-core/drm_objects.h
@@ -141,6 +141,7 @@ extern int drm_user_object_unref(drm_file_t * priv, uint32_t user_token,
 
 typedef struct drm_fence_object {
 	drm_user_object_t base;
+        struct drm_device *dev;
 	atomic_t usage;
 
 	/*
@@ -196,17 +197,15 @@ extern void drm_fence_manager_init(struct drm_device *dev);
 extern void drm_fence_manager_takedown(struct drm_device *dev);
 extern void drm_fence_flush_old(struct drm_device *dev, uint32_t class,
 				uint32_t sequence);
-extern int drm_fence_object_flush(struct drm_device *dev,
-				  drm_fence_object_t * fence, uint32_t type);
-extern int drm_fence_object_signaled(struct drm_device *dev, 
-				     drm_fence_object_t * fence, 
+extern int drm_fence_object_flush(drm_fence_object_t * fence, uint32_t type);
+extern int drm_fence_object_signaled(drm_fence_object_t * fence,
 				     uint32_t type, int flush);
-extern void drm_fence_usage_deref_locked(struct drm_device *dev,
-					 drm_fence_object_t * fence);
-extern void drm_fence_usage_deref_unlocked(struct drm_device *dev,
-					   drm_fence_object_t * fence);
-extern int drm_fence_object_wait(struct drm_device *dev,
-				 drm_fence_object_t * fence,
+extern void drm_fence_usage_deref_locked(drm_fence_object_t ** fence);
+extern void drm_fence_usage_deref_unlocked(drm_fence_object_t ** fence);
+extern struct drm_fence_object *drm_fence_reference_locked(struct drm_fence_object *src);
+extern void drm_fence_reference_unlocked(struct drm_fence_object **dst,
+					 struct drm_fence_object *src);
+extern int drm_fence_object_wait(drm_fence_object_t * fence,
 				 int lazy, int ignore_signals, uint32_t mask);
 extern int drm_fence_object_create(struct drm_device *dev, uint32_t type,
 				   uint32_t fence_flags, uint32_t class,
@@ -441,7 +440,7 @@ extern int drm_bo_pci_offset(struct drm_device *dev,
 			     unsigned long *bus_size);
 extern int drm_mem_reg_is_pci(struct drm_device *dev, drm_bo_mem_reg_t * mem);
 
-extern void drm_bo_usage_deref_locked(drm_buffer_object_t * bo);
+extern void drm_bo_usage_deref_locked(drm_buffer_object_t ** bo);
 extern int drm_fence_buffer_objects(drm_file_t * priv,
 				    struct list_head *list,
 				    uint32_t fence_flags,
diff --git a/linux-core/drm_vm.c b/linux-core/drm_vm.c
index f2c43508..72d63c10 100644
--- a/linux-core/drm_vm.c
+++ b/linux-core/drm_vm.c
@@ -840,7 +840,8 @@ static void drm_bo_vm_close(struct vm_area_struct *vma)
 #ifdef DRM_ODD_MM_COMPAT
 		drm_bo_delete_vma(bo, vma);
 #endif
-		drm_bo_usage_deref_locked(bo);
+		drm_bo_usage_deref_locked((struct drm_buffer_object **)
+					  &vma->vm_private_data);
 		mutex_unlock(&dev->struct_mutex);
 	}
 	return;