diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h
index b0fc9c1..edacd48 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -154,7 +154,6 @@
  * keeps one refcount. When this refcount reaches zero,
  * the object is destroyed.
  * @event_queue: Queue for processes waiting on buffer object status change.
- * @lock: spinlock protecting mostly synchronization members.
  * @mem: structure describing current placement.
  * @persistant_swap_storage: Usually the swap storage is deleted for buffers
  * pinned in physical memory. If this behaviour is not desired, this member
@@ -213,7 +212,6 @@
 	struct kref kref;
 	struct kref list_kref;
 	wait_queue_head_t event_queue;
-	spinlock_t lock;
 
 	/**
 	 * Members protected by the bo::reserved lock.
@@ -248,10 +246,10 @@
 	atomic_t reserved;
 
 	/**
-	 * Members protected by the bo::lock
+	 * Members protected by struct buffer_object_device::fence_lock
 	 * In addition, setting sync_obj to anything else
 	 * than NULL requires bo::reserved to be held. This allows for
-	 * checking NULL while reserved but not holding bo::lock.
+	 * checking NULL while reserved but not holding the mentioned lock.
 	 */
 
 	void *sync_obj_arg;
diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index 1e25a40..ca8131e 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -510,6 +510,8 @@
  *
  * @driver: Pointer to a struct ttm_bo_driver struct setup by the driver.
  * @man: An array of mem_type_managers.
+ * @fence_lock: Protects the synchronizing members on *all* bos belonging
+ * to this device.
  * @addr_space_mm: Range manager for the device address space.
  * lru_lock: Spinlock that protects the buffer+device lru lists and
  * ddestroy lists.
@@ -531,6 +533,7 @@
 	struct ttm_bo_driver *driver;
 	rwlock_t vm_lock;
 	struct ttm_mem_type_manager man[TTM_NUM_MEM_TYPES];
+	spinlock_t fence_lock;
 	/*
 	 * Protected by the vm lock.
 	 */