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authorMatthew Wilcox <matthew@wil.cx>2008-03-07 21:55:58 -0500
committerMatthew Wilcox <willy@linux.intel.com>2008-04-17 10:42:34 -0400
commit64ac24e738823161693bf791f87adc802cf529ff (patch)
tree19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-m32r
parente48b3deee475134585eed03e7afebe4bf9e0dba9 (diff)
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>
Diffstat (limited to 'include/asm-m32r')
-rw-r--r--include/asm-m32r/semaphore.h145
1 files changed, 1 insertions, 144 deletions
diff --git a/include/asm-m32r/semaphore.h b/include/asm-m32r/semaphore.h
index b5bf95a6f2b..d9b2034ed1d 100644
--- a/include/asm-m32r/semaphore.h
+++ b/include/asm-m32r/semaphore.h
@@ -1,144 +1 @@
-#ifndef _ASM_M32R_SEMAPHORE_H
-#define _ASM_M32R_SEMAPHORE_H
-
-#include <linux/linkage.h>
-
-#ifdef __KERNEL__
-
-/*
- * SMP- and interrupt-safe semaphores..
- *
- * Copyright (C) 1996 Linus Torvalds
- * Copyright (C) 2004, 2006 Hirokazu Takata <takata at linux-m32r.org>
- */
-
-#include <linux/wait.h>
-#include <linux/rwsem.h>
-#include <asm/assembler.h>
-#include <asm/system.h>
-#include <asm/atomic.h>
-
-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);
- *
- * i'd rather use the more flexible initialization above, but sadly
- * GCC 2.7.2.3 emits a bogus warning. EGCS doesnt. Oh well.
- */
- atomic_set(&sem->count, val);
- sem->sleepers = 0;
- init_waitqueue_head(&sem->wait);
-}
-
-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);
-
-/*
- * Atomically decrement the semaphore's count. If it goes negative,
- * block the calling thread in the TASK_UNINTERRUPTIBLE state.
- */
-static inline void down(struct semaphore * sem)
-{
- might_sleep();
- if (unlikely(atomic_dec_return(&sem->count) < 0))
- __down(sem);
-}
-
-/*
- * 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)
-{
- int result = 0;
-
- might_sleep();
- if (unlikely(atomic_dec_return(&sem->count) < 0))
- result = __down_interruptible(sem);
-
- return result;
-}
-
-/*
- * Non-blockingly attempt to down() a semaphore.
- * Returns zero if we acquired it
- */
-static inline int down_trylock(struct semaphore * sem)
-{
- unsigned long flags;
- long count;
- int result = 0;
-
- local_irq_save(flags);
- __asm__ __volatile__ (
- "# down_trylock \n\t"
- DCACHE_CLEAR("%0", "r4", "%1")
- M32R_LOCK" %0, @%1; \n\t"
- "addi %0, #-1; \n\t"
- M32R_UNLOCK" %0, @%1; \n\t"
- : "=&r" (count)
- : "r" (&sem->count)
- : "memory"
-#ifdef CONFIG_CHIP_M32700_TS1
- , "r4"
-#endif /* CONFIG_CHIP_M32700_TS1 */
- );
- local_irq_restore(flags);
-
- if (unlikely(count < 0))
- result = __down_trylock(sem);
-
- return result;
-}
-
-/*
- * 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)
-{
- if (unlikely(atomic_inc_return(&sem->count) <= 0))
- __up(sem);
-}
-
-#endif /* __KERNEL__ */
-
-#endif /* _ASM_M32R_SEMAPHORE_H */
+#include <linux/semaphore.h>