diff --git a/sql/mdl.h b/sql/mdl.h
index 4a9397fe215..e0934cb732b 100644
--- a/sql/mdl.h
+++ b/sql/mdl.h
@@ -286,21 +286,6 @@ private:
 };
 
 
-
-/**
-  Hook class which via its methods specifies which members
-  of T should be used for participating in MDL lists.
-*/
-
-template <typename T, T* T::*next, T** T::*prev>
-struct I_P_List_adapter
-{
-  static inline T **next_ptr(T *el) { return &(el->*next); }
-
-  static inline T ***prev_ptr(T *el) { return &(el->*prev); }
-};
-
-
 /**
   A pending metadata lock request.
 
diff --git a/sql/sql_plist.h b/sql/sql_plist.h
index db85266be15..4395b9e4e8b 100644
--- a/sql/sql_plist.h
+++ b/sql/sql_plist.h
@@ -187,6 +187,20 @@ public:
 };
 
 
+/**
+  Hook class which via its methods specifies which members
+  of T should be used for participating in a intrusive list.
+*/
+
+template <typename T, T* T::*next, T** T::*prev>
+struct I_P_List_adapter
+{
+  static inline T **next_ptr(T *el) { return &(el->*next); }
+
+  static inline T ***prev_ptr(T *el) { return &(el->*prev); }
+};
+
+
 /**
   Element counting policy class for I_P_List to be used in
   cases when no element counting should be done.