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>
156 lines
3.5 KiB
C
156 lines
3.5 KiB
C
/* semaphore.h: semaphores for the FR-V
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*
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* Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef _ASM_SEMAPHORE_H
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#define _ASM_SEMAPHORE_H
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#define RW_LOCK_BIAS 0x01000000
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#ifndef __ASSEMBLY__
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#include <linux/linkage.h>
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#include <linux/wait.h>
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#include <linux/spinlock.h>
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#include <linux/rwsem.h>
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/*
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* the semaphore definition
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* - if counter is >0 then there are tokens available on the semaphore for down to collect
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* - if counter is <=0 then there are no spare tokens, and anyone that wants one must wait
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* - if wait_list is not empty, then there are processes waiting for the semaphore
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*/
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struct semaphore {
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unsigned counter;
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spinlock_t wait_lock;
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struct list_head wait_list;
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#ifdef CONFIG_DEBUG_SEMAPHORE
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unsigned __magic;
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#endif
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};
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#ifdef CONFIG_DEBUG_SEMAPHORE
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# define __SEM_DEBUG_INIT(name) , (long)&(name).__magic
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#else
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# define __SEM_DEBUG_INIT(name)
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#endif
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#define __SEMAPHORE_INITIALIZER(name,count) \
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{ count, SPIN_LOCK_UNLOCKED, LIST_HEAD_INIT((name).wait_list) __SEM_DEBUG_INIT(name) }
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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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*sem = (struct semaphore) __SEMAPHORE_INITIALIZER(*sem, val);
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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 *sem, unsigned long flags);
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extern int __down_interruptible(struct semaphore *sem, unsigned long flags);
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extern void __up(struct semaphore *sem);
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static inline void down(struct semaphore *sem)
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{
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unsigned long flags;
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#ifdef CONFIG_DEBUG_SEMAPHORE
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CHECK_MAGIC(sem->__magic);
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#endif
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spin_lock_irqsave(&sem->wait_lock, flags);
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if (likely(sem->counter > 0)) {
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sem->counter--;
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spin_unlock_irqrestore(&sem->wait_lock, flags);
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}
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else {
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__down(sem, flags);
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}
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}
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static inline int down_interruptible(struct semaphore *sem)
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{
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unsigned long flags;
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int ret = 0;
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#ifdef CONFIG_DEBUG_SEMAPHORE
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CHECK_MAGIC(sem->__magic);
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#endif
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spin_lock_irqsave(&sem->wait_lock, flags);
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if (likely(sem->counter > 0)) {
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sem->counter--;
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spin_unlock_irqrestore(&sem->wait_lock, flags);
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}
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else {
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ret = __down_interruptible(sem, flags);
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}
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return ret;
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}
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/*
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* non-blockingly attempt to down() a semaphore.
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* - returns zero if we acquired it
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*/
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static inline int down_trylock(struct semaphore *sem)
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{
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unsigned long flags;
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int success = 0;
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#ifdef CONFIG_DEBUG_SEMAPHORE
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CHECK_MAGIC(sem->__magic);
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#endif
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spin_lock_irqsave(&sem->wait_lock, flags);
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if (sem->counter > 0) {
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sem->counter--;
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success = 1;
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}
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spin_unlock_irqrestore(&sem->wait_lock, flags);
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return !success;
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}
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static inline void up(struct semaphore *sem)
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{
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unsigned long flags;
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#ifdef CONFIG_DEBUG_SEMAPHORE
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CHECK_MAGIC(sem->__magic);
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#endif
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spin_lock_irqsave(&sem->wait_lock, flags);
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if (!list_empty(&sem->wait_list))
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__up(sem);
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else
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sem->counter++;
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spin_unlock_irqrestore(&sem->wait_lock, flags);
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}
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static inline int sem_getcount(struct semaphore *sem)
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{
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return sem->counter;
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}
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#endif /* __ASSEMBLY__ */
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#endif
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