From: Ben Hutchings <ben@decadent.org.uk>
Date: Tue, 14 Jun 2016 20:13:23 +0100
Subject: [PATCH 5/7] liblockdep: Fix 'unused value' warnings
Forwarded: http://mid.gmane.org/20160614204853.GX7555@decadent.org.uk

liblockdep defines various macros that may expand to an expression
with no effect, while the in-kernel definition does have an effect.
This results in warnings from gcc when -Wunused-value is enabled, and
is is enabled by -Wall.  Fix this by introducing trivial functions,
as function return values are generally allowed to be ignored.

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 tools/lib/lockdep/uinclude/linux/debug_locks.h |  2 +-
 tools/lib/lockdep/uinclude/linux/kernel.h      | 12 +++++++++---
 tools/lib/lockdep/uinclude/linux/lockdep.h     |  6 +++++-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/tools/lib/lockdep/uinclude/linux/debug_locks.h b/tools/lib/lockdep/uinclude/linux/debug_locks.h
index f38eb64df794..1d4fbec5c649 100644
--- a/tools/lib/lockdep/uinclude/linux/debug_locks.h
+++ b/tools/lib/lockdep/uinclude/linux/debug_locks.h
@@ -4,7 +4,7 @@
 #include <stddef.h>
 #include <linux/compiler.h>
 
-#define DEBUG_LOCKS_WARN_ON(x) (x)
+#define DEBUG_LOCKS_WARN_ON(x) WARN_ON(x)
 
 extern bool debug_locks;
 extern bool debug_locks_silent;
diff --git a/tools/lib/lockdep/uinclude/linux/kernel.h b/tools/lib/lockdep/uinclude/linux/kernel.h
index da87bd9ad2c1..021cff4f4e3d 100644
--- a/tools/lib/lockdep/uinclude/linux/kernel.h
+++ b/tools/lib/lockdep/uinclude/linux/kernel.h
@@ -22,10 +22,16 @@
 	_max1 > _max2 ? _max1 : _max2; })
 
 #define BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
-#define WARN_ON(x) (x)
-#define WARN_ON_ONCE(x) (x)
+
+static inline int lockdep_warn(int condition)
+{
+	return condition;
+}
+#define WARN_ON(x) lockdep_warn(x)
+#define WARN_ON_ONCE(x) WARN_ON(x)
+#define WARN(x, y...) WARN_ON(x)
+
 #define likely(x) (x)
-#define WARN(x, y...) (x)
 #define uninitialized_var(x) x
 #define __init
 #define noinline
diff --git a/tools/lib/lockdep/uinclude/linux/lockdep.h b/tools/lib/lockdep/uinclude/linux/lockdep.h
index d30214221920..d1079034a14d 100644
--- a/tools/lib/lockdep/uinclude/linux/lockdep.h
+++ b/tools/lib/lockdep/uinclude/linux/lockdep.h
@@ -29,7 +29,11 @@ extern struct task_struct *__curr(void);
 
 #define current (__curr())
 
-#define debug_locks_off() 1
+static inline int debug_locks_off(void)
+{
+	return 1;
+}
+
 #define task_pid_nr(tsk) ((tsk)->pid)
 
 #define KSYM_NAME_LEN 128
