1 files changed, 2 insertions, 1 deletions

diff --git a/include/linux/idr.h b/include/linux/idr.h
index fa035f96f2a3..dd846df8cd32 100644
--- a/include/linux/idr.h
+++ b/include/linux/idr.h
@@ -52,13 +52,14 @@ struct idr_layer {
         unsigned long            bitmap; /* A zero bit means "space here" */
         struct idr_layer        *ary[1<<IDR_BITS];
         int                      count;  /* When zero, we can release it */
+        int                      layer;  /* distance from leaf */
         struct rcu_head          rcu_head;
 };
 
 struct idr {
         struct idr_layer *top;
         struct idr_layer *id_free;
-        int               layers;
+        int               layers; /* only valid without concurrent changes */
         int               id_free_cnt;
         spinlock_t        lock;
 };