2 files changed, 4 insertions, 2 deletions

diff --git a/include/linux/mutex.h b/include/linux/mutex.h
index 7a0e5c4f8072..3069ec7e0ab8 100644
--- a/include/linux/mutex.h
+++ b/include/linux/mutex.h
@@ -50,8 +50,10 @@ struct mutex {
         atomic_t                count;
         spinlock_t              wait_lock;
         struct list_head        wait_list;
-#ifdef CONFIG_DEBUG_MUTEXES
+#if defined(CONFIG_DEBUG_MUTEXES) || defined(CONFIG_SMP)
         struct thread_info      *owner;
+#endif
+#ifdef CONFIG_DEBUG_MUTEXES
         const char              *name;
         void                    *magic;
 #endif
@@ -68,7 +70,6 @@ struct mutex_waiter {
         struct list_head        list;
         struct task_struct      *task;
 #ifdef CONFIG_DEBUG_MUTEXES
-        struct mutex            *lock;
         void                    *magic;
 #endif
 };
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9f0b372cfa6f..c34b137cd1e5 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -330,6 +330,7 @@ extern signed long schedule_timeout_killable(signed long timeout);
 extern signed long schedule_timeout_uninterruptible(signed long timeout);
 asmlinkage void __schedule(void);
 asmlinkage void schedule(void);
+extern int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner);
 
 struct nsproxy;
 struct user_namespace;