04fc8bbcf5
DECLARE_MUTEX_LOCKED was used for semaphores used as completions and we've got rid of them. Well, except for one in libusual that the maintainer explicitly wants to keep as semaphore. So convert that useage to an explicit sema_init and kill of DECLARE_MUTEX_LOCKED so that new code is reminded to use a completion. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: "Satyam Sharma" <satyam.sharma@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
150 lines
3.1 KiB
C
150 lines
3.1 KiB
C
#ifndef _ALPHA_SEMAPHORE_H
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#define _ALPHA_SEMAPHORE_H
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/*
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* SMP- and interrupt-safe semaphores..
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*
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* (C) Copyright 1996 Linus Torvalds
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* (C) Copyright 1996, 2000 Richard Henderson
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*/
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#include <asm/current.h>
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#include <asm/system.h>
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#include <asm/atomic.h>
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#include <linux/compiler.h>
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#include <linux/wait.h>
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#include <linux/rwsem.h>
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struct semaphore {
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atomic_t count;
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wait_queue_head_t wait;
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};
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#define __SEMAPHORE_INITIALIZER(name, n) \
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{ \
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.count = ATOMIC_INIT(n), \
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.wait = __WAIT_QUEUE_HEAD_INITIALIZER((name).wait), \
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}
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#define __DECLARE_SEMAPHORE_GENERIC(name,count) \
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struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
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#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name,1)
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static inline void sema_init(struct semaphore *sem, int val)
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{
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/*
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* Logically,
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* *sem = (struct semaphore)__SEMAPHORE_INITIALIZER((*sem),val);
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* except that gcc produces better initializing by parts yet.
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*/
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atomic_set(&sem->count, val);
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init_waitqueue_head(&sem->wait);
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}
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static inline void init_MUTEX (struct semaphore *sem)
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{
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sema_init(sem, 1);
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}
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static inline void init_MUTEX_LOCKED (struct semaphore *sem)
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{
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sema_init(sem, 0);
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}
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extern void down(struct semaphore *);
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extern void __down_failed(struct semaphore *);
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extern int down_interruptible(struct semaphore *);
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extern int __down_failed_interruptible(struct semaphore *);
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extern int down_trylock(struct semaphore *);
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extern void up(struct semaphore *);
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extern void __up_wakeup(struct semaphore *);
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/*
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* Hidden out of line code is fun, but extremely messy. Rely on newer
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* compilers to do a respectable job with this. The contention cases
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* are handled out of line in arch/alpha/kernel/semaphore.c.
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*/
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static inline void __down(struct semaphore *sem)
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{
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long count;
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might_sleep();
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count = atomic_dec_return(&sem->count);
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if (unlikely(count < 0))
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__down_failed(sem);
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}
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static inline int __down_interruptible(struct semaphore *sem)
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{
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long count;
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might_sleep();
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count = atomic_dec_return(&sem->count);
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if (unlikely(count < 0))
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return __down_failed_interruptible(sem);
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return 0;
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}
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/*
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* down_trylock returns 0 on success, 1 if we failed to get the lock.
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*/
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static inline int __down_trylock(struct semaphore *sem)
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{
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long ret;
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/* "Equivalent" C:
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do {
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ret = ldl_l;
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--ret;
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if (ret < 0)
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break;
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ret = stl_c = ret;
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} while (ret == 0);
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*/
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__asm__ __volatile__(
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"1: ldl_l %0,%1\n"
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" subl %0,1,%0\n"
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" blt %0,2f\n"
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" stl_c %0,%1\n"
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" beq %0,3f\n"
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" mb\n"
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"2:\n"
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".subsection 2\n"
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"3: br 1b\n"
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".previous"
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: "=&r" (ret), "=m" (sem->count)
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: "m" (sem->count));
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return ret < 0;
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}
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static inline void __up(struct semaphore *sem)
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{
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if (unlikely(atomic_inc_return(&sem->count) <= 0))
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__up_wakeup(sem);
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}
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#if !defined(CONFIG_DEBUG_SEMAPHORE)
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extern inline void down(struct semaphore *sem)
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{
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__down(sem);
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}
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extern inline int down_interruptible(struct semaphore *sem)
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{
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return __down_interruptible(sem);
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}
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extern inline int down_trylock(struct semaphore *sem)
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{
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return __down_trylock(sem);
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}
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extern inline void up(struct semaphore *sem)
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{
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__up(sem);
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}
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#endif
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#endif
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