Generic semaphore implementation

Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility.  Thanks to Peter Zijlstra for fixing the lockdep
warning.  Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.

Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 1 insertions, 275 deletions

diff --git a/include/asm-h8300/semaphore-helper.h b/include/asm-h8300/semaphore-helper.h
deleted file mode 100644
index 4fea36b..0000000
--- a/include/asm-h8300/semaphore-helper.h
+++ /dev/null
@@ -1,85 +0,0 @@
-#ifndef _H8300_SEMAPHORE_HELPER_H
-#define _H8300_SEMAPHORE_HELPER_H
-
-/*
- * SMP- and interrupt-safe semaphores helper functions.
- *
- * (C) Copyright 1996 Linus Torvalds
- *
- * based on
- * m68k version by Andreas Schwab
- */
-
-#include <linux/errno.h>
-
-/*
- * These two _must_ execute atomically wrt each other.
- */
-static inline void wake_one_more(struct semaphore * sem)
-{
-	atomic_inc((atomic_t *)&sem->sleepers);
-}
-
-static inline int waking_non_zero(struct semaphore *sem)
-{
-	int ret;
-	unsigned long flags;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	ret = 0;
-	if (sem->sleepers > 0) {
-		sem->sleepers--;
-		ret = 1;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-/*
- * waking_non_zero_interruptible:
- *	1	got the lock
- *	0	go to sleep
- *	-EINTR	interrupted
- */
-static inline int waking_non_zero_interruptible(struct semaphore *sem,
-						struct task_struct *tsk)
-{
-	int ret;
-	unsigned long flags;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	ret = 0;
-	if (sem->sleepers > 0) {
-		sem->sleepers--;
-		ret = 1;
-	} else if (signal_pending(tsk)) {
-		atomic_inc(&sem->count);
-		ret = -EINTR;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-/*
- * waking_non_zero_trylock:
- *	1	failed to lock
- *	0	got the lock
- */
-static inline int waking_non_zero_trylock(struct semaphore *sem)
-{
-	int ret;
-	unsigned long flags;
-
-	spin_lock_irqsave(&semaphore_wake_lock, flags);
-	ret = 1;
-	if (sem->sleepers <= 0)
-		atomic_inc(&sem->count);
-	else {
-		sem->sleepers--;
-		ret = 0;
-	}
-	spin_unlock_irqrestore(&semaphore_wake_lock, flags);
-	return ret;
-}
-
-#endif
diff --git a/include/asm-h8300/semaphore.h b/include/asm-h8300/semaphore.h
index f3ffff8..d9b2034 100644
--- a/include/asm-h8300/semaphore.h
+++ b/include/asm-h8300/semaphore.h
@@ -1,190 +1 @@
-#ifndef _H8300_SEMAPHORE_H
-#define _H8300_SEMAPHORE_H
-
-#define RW_LOCK_BIAS		 0x01000000
-
-#ifndef __ASSEMBLY__
-
-#include <linux/linkage.h>
-#include <linux/wait.h>
-#include <linux/spinlock.h>
-#include <linux/rwsem.h>
-
-#include <asm/system.h>
-#include <asm/atomic.h>
-
-/*
- * Interrupt-safe semaphores..
- *
- * (C) Copyright 1996 Linus Torvalds
- *
- * H8/300 version by Yoshinori Sato
- */
-
-
-struct semaphore {
-	atomic_t count;
-	int sleepers;
-	wait_queue_head_t wait;
-};
-
-#define __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 DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
-
-static inline void sema_init (struct semaphore *sem, int val)
-{
-	*sem = (struct semaphore)__SEMAPHORE_INITIALIZER(*sem, val);
-}
-
-static inline void init_MUTEX (struct semaphore *sem)
-{
-	sema_init(sem, 1);
-}
-
-static inline void init_MUTEX_LOCKED (struct semaphore *sem)
-{
-	sema_init(sem, 0);
-}
-
-asmlinkage void __down_failed(void /* special register calling convention */);
-asmlinkage int  __down_failed_interruptible(void  /* params in registers */);
-asmlinkage int  __down_failed_trylock(void  /* params in registers */);
-asmlinkage void __up_wakeup(void /* special register calling convention */);
-
-asmlinkage void __down(struct semaphore * sem);
-asmlinkage int  __down_interruptible(struct semaphore * sem);
-asmlinkage int  __down_trylock(struct semaphore * sem);
-asmlinkage void __up(struct semaphore * sem);
-
-extern spinlock_t semaphore_wake_lock;
-
-/*
- * This is ugly, but we want the default case to fall through.
- * "down_failed" is a special asm handler that calls the C
- * routine that actually waits. See arch/m68k/lib/semaphore.S
- */
-static inline void down(struct semaphore * sem)
-{
-	register atomic_t *count asm("er0");
-
-	might_sleep();
-
-	count = &(sem->count);
-	__asm__ __volatile__(
-		"stc ccr,r3l\n\t"
-		"orc #0x80,ccr\n\t"
-		"mov.l %2, er1\n\t"
-		"dec.l #1,er1\n\t"
-		"mov.l er1,%0\n\t"
-		"bpl 1f\n\t"
-		"ldc r3l,ccr\n\t"
-		"mov.l %1,er0\n\t"
-		"jsr @___down\n\t"
-		"bra 2f\n"
-		"1:\n\t"
-		"ldc r3l,ccr\n"
-		"2:"
-		: "=m"(*count)
-		: "g"(sem),"m"(*count)
-		: "cc",  "er1", "er2", "er3");
-}
-
-static inline int down_interruptible(struct semaphore * sem)
-{
-	register atomic_t *count asm("er0");
-
-	might_sleep();
-
-	count = &(sem->count);
-	__asm__ __volatile__(
-		"stc ccr,r1l\n\t"
-		"orc #0x80,ccr\n\t"
-		"mov.l %3, er2\n\t"
-		"dec.l #1,er2\n\t"
-		"mov.l er2,%1\n\t"
-		"bpl 1f\n\t"
-		"ldc r1l,ccr\n\t"
-		"mov.l %2,er0\n\t"
-		"jsr @___down_interruptible\n\t"
-		"bra 2f\n"
-		"1:\n\t"
-		"ldc r1l,ccr\n\t"
-		"sub.l %0,%0\n\t"
-		"2:\n\t"
-		: "=r" (count),"=m" (*count)
-		: "g"(sem),"m"(*count)
-		: "cc", "er1", "er2", "er3");
-	return (int)count;
-}
-
-static inline int down_trylock(struct semaphore * sem)
-{
-	register atomic_t *count asm("er0");
-
-	count = &(sem->count);
-	__asm__ __volatile__(
-		"stc ccr,r3l\n\t"
-		"orc #0x80,ccr\n\t"
-		"mov.l %3,er2\n\t"
-		"dec.l #1,er2\n\t"
-		"mov.l er2,%0\n\t"
-		"bpl 1f\n\t"
-		"ldc r3l,ccr\n\t"
-		"jmp @3f\n\t"
-		LOCK_SECTION_START(".align 2\n\t")
-		"3:\n\t"
-		"mov.l %2,er0\n\t"
-		"jsr @___down_trylock\n\t"
-		"jmp @2f\n\t"
-		LOCK_SECTION_END
-		"1:\n\t"
-		"ldc r3l,ccr\n\t"
-		"sub.l %1,%1\n"
-		"2:"
-		: "=m" (*count),"=r"(count)
-		: "g"(sem),"m"(*count)
-		: "cc", "er1","er2", "er3");
-	return (int)count;
-}
-
-/*
- * Note! This is subtle. We jump to wake people up only if
- * the semaphore was negative (== somebody was waiting on it).
- * The default case (no contention) will result in NO
- * jumps for both down() and up().
- */
-static inline void up(struct semaphore * sem)
-{
-	register atomic_t *count asm("er0");
-
-	count = &(sem->count);
-	__asm__ __volatile__(
-		"stc ccr,r3l\n\t"
-		"orc #0x80,ccr\n\t"
-		"mov.l %2,er1\n\t"
-		"inc.l #1,er1\n\t"
-		"mov.l er1,%0\n\t"
-		"ldc r3l,ccr\n\t"
-		"sub.l er2,er2\n\t"
-		"cmp.l er2,er1\n\t"
-		"bgt 1f\n\t"
-		"mov.l %1,er0\n\t"
-		"jsr @___up\n"
-		"1:"
-		: "=m"(*count)
-		: "g"(sem),"m"(*count)
-		: "cc", "er1", "er2", "er3");
-}
-
-#endif /* __ASSEMBLY__ */
-
-#endif
+#include <linux/semaphore.h>