diff options
author | Matthew Wilcox <matthew@wil.cx> | 2008-03-07 21:55:58 -0500 |
---|---|---|
committer | Matthew Wilcox <willy@linux.intel.com> | 2008-04-17 10:42:34 -0400 |
commit | 64ac24e738823161693bf791f87adc802cf529ff (patch) | |
tree | 19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-m68k/semaphore.h | |
parent | e48b3deee475134585eed03e7afebe4bf9e0dba9 (diff) | |
download | linux-stable-64ac24e738823161693bf791f87adc802cf529ff.tar.gz linux-stable-64ac24e738823161693bf791f87adc802cf529ff.tar.bz2 linux-stable-64ac24e738823161693bf791f87adc802cf529ff.zip |
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-m68k/semaphore.h')
-rw-r--r-- | include/asm-m68k/semaphore.h | 164 |
1 files changed, 1 insertions, 163 deletions
diff --git a/include/asm-m68k/semaphore.h b/include/asm-m68k/semaphore.h index 64d6b119bb0a..d9b2034ed1d2 100644 --- a/include/asm-m68k/semaphore.h +++ b/include/asm-m68k/semaphore.h @@ -1,163 +1 @@ -#ifndef _M68K_SEMAPHORE_H -#define _M68K_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 <linux/stringify.h> - -#include <asm/system.h> -#include <asm/atomic.h> - -/* - * Interrupt-safe semaphores.. - * - * (C) Copyright 1996 Linus Torvalds - * - * m68k version by Andreas Schwab - */ - - -struct semaphore { - atomic_t count; - atomic_t waking; - wait_queue_head_t wait; -}; - -#define __SEMAPHORE_INITIALIZER(name, n) \ -{ \ - .count = ATOMIC_INIT(n), \ - .waking = ATOMIC_INIT(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); - -/* - * 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 struct semaphore *sem1 __asm__ ("%a1") = sem; - - might_sleep(); - __asm__ __volatile__( - "| atomic down operation\n\t" - "subql #1,%0@\n\t" - "jmi 2f\n\t" - "1:\n" - LOCK_SECTION_START(".even\n\t") - "2:\tpea 1b\n\t" - "jbra __down_failed\n" - LOCK_SECTION_END - : /* no outputs */ - : "a" (sem1) - : "memory"); -} - -static inline int down_interruptible(struct semaphore *sem) -{ - register struct semaphore *sem1 __asm__ ("%a1") = sem; - register int result __asm__ ("%d0"); - - might_sleep(); - __asm__ __volatile__( - "| atomic interruptible down operation\n\t" - "subql #1,%1@\n\t" - "jmi 2f\n\t" - "clrl %0\n" - "1:\n" - LOCK_SECTION_START(".even\n\t") - "2:\tpea 1b\n\t" - "jbra __down_failed_interruptible\n" - LOCK_SECTION_END - : "=d" (result) - : "a" (sem1) - : "memory"); - return result; -} - -static inline int down_trylock(struct semaphore *sem) -{ - register struct semaphore *sem1 __asm__ ("%a1") = sem; - register int result __asm__ ("%d0"); - - __asm__ __volatile__( - "| atomic down trylock operation\n\t" - "subql #1,%1@\n\t" - "jmi 2f\n\t" - "clrl %0\n" - "1:\n" - LOCK_SECTION_START(".even\n\t") - "2:\tpea 1b\n\t" - "jbra __down_failed_trylock\n" - LOCK_SECTION_END - : "=d" (result) - : "a" (sem1) - : "memory"); - 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) -{ - register struct semaphore *sem1 __asm__ ("%a1") = sem; - - __asm__ __volatile__( - "| atomic up operation\n\t" - "addql #1,%0@\n\t" - "jle 2f\n" - "1:\n" - LOCK_SECTION_START(".even\n\t") - "2:\t" - "pea 1b\n\t" - "jbra __up_wakeup\n" - LOCK_SECTION_END - : /* no outputs */ - : "a" (sem1) - : "memory"); -} - -#endif /* __ASSEMBLY__ */ - -#endif +#include <linux/semaphore.h> |