v4.19.13 snapshot.
diff --git a/include/linux/debug_locks.h b/include/linux/debug_locks.h
new file mode 100644
index 0000000..120225e
--- /dev/null
+++ b/include/linux/debug_locks.h
@@ -0,0 +1,76 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_DEBUG_LOCKING_H
+#define __LINUX_DEBUG_LOCKING_H
+
+#include <linux/kernel.h>
+#include <linux/atomic.h>
+#include <linux/bug.h>
+
+struct task_struct;
+
+extern int debug_locks;
+extern int debug_locks_silent;
+
+
+static inline int __debug_locks_off(void)
+{
+ return xchg(&debug_locks, 0);
+}
+
+/*
+ * Generic 'turn off all lock debugging' function:
+ */
+extern int debug_locks_off(void);
+
+#define DEBUG_LOCKS_WARN_ON(c) \
+({ \
+ int __ret = 0; \
+ \
+ if (!oops_in_progress && unlikely(c)) { \
+ if (debug_locks_off() && !debug_locks_silent) \
+ WARN(1, "DEBUG_LOCKS_WARN_ON(%s)", #c); \
+ __ret = 1; \
+ } \
+ __ret; \
+})
+
+#ifdef CONFIG_SMP
+# define SMP_DEBUG_LOCKS_WARN_ON(c) DEBUG_LOCKS_WARN_ON(c)
+#else
+# define SMP_DEBUG_LOCKS_WARN_ON(c) do { } while (0)
+#endif
+
+#ifdef CONFIG_DEBUG_LOCKING_API_SELFTESTS
+ extern void locking_selftest(void);
+#else
+# define locking_selftest() do { } while (0)
+#endif
+
+struct task_struct;
+
+#ifdef CONFIG_LOCKDEP
+extern void debug_show_all_locks(void);
+extern void debug_show_held_locks(struct task_struct *task);
+extern void debug_check_no_locks_freed(const void *from, unsigned long len);
+extern void debug_check_no_locks_held(void);
+#else
+static inline void debug_show_all_locks(void)
+{
+}
+
+static inline void debug_show_held_locks(struct task_struct *task)
+{
+}
+
+static inline void
+debug_check_no_locks_freed(const void *from, unsigned long len)
+{
+}
+
+static inline void
+debug_check_no_locks_held(void)
+{
+}
+#endif
+
+#endif