1 files changed, 6 insertions, 0 deletions

diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index b25d1b53df0d..9ec026f8d09e 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -149,6 +149,12 @@ struct lock_list {
         struct lock_class               *class;
         struct stack_trace              trace;
         int                             distance;
+
+        /*The parent field is used to implement breadth-first search,and
+         *the bit 0 is reused to indicate if the lock has been accessed
+         *in BFS.
+         */
+        struct lock_list                *parent;
 };
 
 /*