semaphore-Remove-mutex-emulation.patch

From 1f9dda3f32289a4763f8f2233e62835cc6dab152 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 26 Jul 2009 00:36:48 +0200
Subject: [PATCH] semaphore: Remove mutex emulation

commit a15032a6f554018c0a96e923645e01f51519e22b in tip.

Semaphores used as mutexes have been deprecated for years. Now that
all users are either converted to real semaphores or to mutexes remove
the cruft.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/include/linux/semaphore.h b/include/linux/semaphore.h
index b3669e8..aaeced9 100644
--- a/include/linux/semaphore.h
+++ b/include/linux/semaphore.h
@@ -29,9 +29,6 @@ struct semaphore {
 #define DEFINE_SEMAPHORE(name, val)					\
 	struct semaphore name = __SEMAPHORE_INITIALIZER(name, val)
 
-#define DECLARE_MUTEX(name)	\
-	struct semaphore name = __SEMAPHORE_INITIALIZER(name, 1)
-
 static inline void sema_init(struct semaphore *sem, int val)
 {
 	static struct lock_class_key __key;
@@ -39,9 +36,6 @@ static inline void sema_init(struct semaphore *sem, int val)
 	lockdep_init_map(&sem->lock.dep_map, "semaphore->lock", &__key, 0);
 }
 
-#define init_MUTEX(sem)		sema_init(sem, 1)
-#define init_MUTEX_LOCKED(sem)	sema_init(sem, 0)
-
 extern void down(struct semaphore *sem);
 extern int __must_check down_interruptible(struct semaphore *sem);
 extern int __must_check down_killable(struct semaphore *sem);
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 3257d3d..46f47ac 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2618,14 +2618,11 @@ sub process {
 			WARN("__func__ should be used instead of gcc specific __FUNCTION__\n"  . $herecurr);
 		}
 
-# check for semaphores used as mutexes
-		if ($line =~ /^.\s*(DECLARE_MUTEX|init_MUTEX)\s*\(/) {
-			WARN("mutexes are preferred for single holder semaphores\n" . $herecurr);
-		}
-# check for semaphores used as mutexes
-		if ($line =~ /^.\s*init_MUTEX_LOCKED\s*\(/) {
+# check for semaphores initialized locked
+		if ($line =~ /sema_init\(.*,\s*0\)/) {
 			WARN("consider using a completion\n" . $herecurr);
 		}
+
 # recommend strict_strto* over simple_strto*
 		if ($line =~ /\bsimple_(strto.*?)\s*\(/) {
 			WARN("consider using strict_$1 in preference to simple_$1\n" . $herecurr);
-- 
1.7.1.1