[patch 08/15] Generic Mutex Subsystem, mutex-migration-helper-i386.patch

[Ingo Molnar <mingo@elte.hu>]

introduce the arch_semaphore type on i386, to ease migration to mutexes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

----

 arch/i386/Kconfig            |    4 +++
 include/asm-i386/semaphore.h |   52 +++++++++++++++++++++++++++----------------
 2 files changed, 37 insertions(+), 19 deletions(-)

Index: linux/arch/i386/Kconfig
===================================================================
--- linux.orig/arch/i386/Kconfig
+++ linux/arch/i386/Kconfig
@@ -18,6 +18,10 @@ config SEMAPHORE_SLEEPERS
 	bool
 	default y
 
+config ARCH_SEMAPHORES
+	bool
+	default y
+
 config X86
 	bool
 	default y
Index: linux/include/asm-i386/semaphore.h
===================================================================
--- linux.orig/include/asm-i386/semaphore.h
+++ linux/include/asm-i386/semaphore.h
@@ -1,10 +1,9 @@
 #ifndef _I386_SEMAPHORE_H
 #define _I386_SEMAPHORE_H
 
+#include <linux/config.h>
 #include <linux/linkage.h>
 
-#ifdef __KERNEL__
-
 /*
  * SMP- and interrupt-safe semaphores..
  *
@@ -41,30 +40,40 @@
 #include <linux/wait.h>
 #include <linux/rwsem.h>
 
-struct semaphore {
+/*
+ * On !DEBUG_MUTEX_FULL, all semaphores map to the arch implementation:
+ */
+#ifndef CONFIG_DEBUG_MUTEX_FULL
+# define arch_semaphore semaphore
+#endif
+
+struct arch_semaphore {
 	atomic_t count;
 	int sleepers;
 	wait_queue_head_t wait;
 };
 
 
-#define __SEMAPHORE_INITIALIZER(name, n)				\
+#define __ARCH_SEMAPHORE_INITIALIZER(name, n)				\
 {									\
 	.count		= ATOMIC_INIT(n),				\
 	.sleepers	= 0,						\
 	.wait		= __WAIT_QUEUE_HEAD_INITIALIZER((name).wait)	\
 }
 
-#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
-	struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
+#define __ARCH_MUTEX_INITIALIZER(name) \
+	__ARCH_SEMAPHORE_INITIALIZER(name,1)
 
-#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
-#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name,0)
+#define __ARCH_DECLARE_SEMAPHORE_GENERIC(name,count) \
+	struct arch_semaphore name = __ARCH_SEMAPHORE_INITIALIZER(name,count)
 
-static inline void sema_init (struct semaphore *sem, int val)
+#define ARCH_DECLARE_MUTEX(name) __ARCH_DECLARE_SEMAPHORE_GENERIC(name,1)
+#define ARCH_DECLARE_MUTEX_LOCKED(name) __ARCH_DECLARE_SEMAPHORE_GENERIC(name,0)
+
+static inline void arch_sema_init (struct arch_semaphore *sem, int val)
 {
 /*
- *	*sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
+ *	*sem = (struct arch_semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
  *
  * i'd rather use the more flexible initialization above, but sadly
  * GCC 2.7.2.3 emits a bogus warning. EGCS doesn't. Oh well.
@@ -74,14 +83,14 @@ static inline void sema_init (struct sem
 	init_waitqueue_head(&sem->wait);
 }
 
-static inline void init_MUTEX (struct semaphore *sem)
+static inline void arch_init_MUTEX (struct arch_semaphore *sem)
 {
-	sema_init(sem, 1);
+	arch_sema_init(sem, 1);
 }
 
-static inline void init_MUTEX_LOCKED (struct semaphore *sem)
+static inline void arch_init_MUTEX_LOCKED (struct arch_semaphore *sem)
 {
-	sema_init(sem, 0);
+	arch_sema_init(sem, 0);
 }
 
 fastcall void __down_failed(void /* special register calling convention */);
@@ -94,7 +103,7 @@ fastcall void __up_wakeup(void /* specia
  * "__down_failed" is a special asm handler that calls the C
  * routine that actually waits. See arch/i386/kernel/semaphore.c
  */
-static inline void down(struct semaphore * sem)
+static inline void arch_down(struct arch_semaphore * sem)
 {
 	might_sleep();
 	__asm__ __volatile__(
@@ -116,7 +125,7 @@ static inline void down(struct semaphore
  * Interruptible try to acquire a semaphore.  If we obtained
  * it, return zero.  If we were interrupted, returns -EINTR
  */
-static inline int down_interruptible(struct semaphore * sem)
+static inline int arch_down_interruptible(struct arch_semaphore * sem)
 {
 	int result;
 
@@ -142,7 +151,7 @@ static inline int down_interruptible(str
  * Non-blockingly attempt to down() a semaphore.
  * Returns zero if we acquired it
  */
-static inline int down_trylock(struct semaphore * sem)
+static inline int arch_down_trylock(struct arch_semaphore * sem)
 {
 	int result;
 
@@ -169,7 +178,7 @@ static inline int down_trylock(struct se
  * The default case (no contention) will result in NO
  * jumps for both down() and up().
  */
-static inline void up(struct semaphore * sem)
+static inline void arch_up(struct arch_semaphore * sem)
 {
 	__asm__ __volatile__(
 		"# atomic up operation\n\t"
@@ -187,5 +196,10 @@ static inline void up(struct semaphore *
 		:"memory","ax");
 }
 
-#endif
+extern int FASTCALL(arch_sem_is_locked(struct arch_semaphore *sem));
+
+#define arch_sema_count(sem) atomic_read(&(sem)->count)
+
+#include <linux/semaphore.h>
+
 #endif