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>
146 lines
3.8 KiB
C
146 lines
3.8 KiB
C
/* SMP- and interrupt-safe semaphores.
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* PA-RISC version by Matthew Wilcox
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*
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* Linux/PA-RISC Project (http://www.parisc-linux.org/)
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* Copyright (C) 1996 Linus Torvalds
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* Copyright (C) 1999-2001 Matthew Wilcox < willy at debian d0T org >
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* Copyright (C) 2000 Grant Grundler < grundler a debian org >
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef _ASM_PARISC_SEMAPHORE_H
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#define _ASM_PARISC_SEMAPHORE_H
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#include <linux/spinlock.h>
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#include <linux/wait.h>
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#include <linux/rwsem.h>
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#include <asm/system.h>
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/*
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* The `count' is initialised to the number of people who are allowed to
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* take the lock. (Normally we want a mutex, so this is `1'). if
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* `count' is positive, the lock can be taken. if it's 0, no-one is
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* waiting on it. if it's -1, at least one task is waiting.
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*/
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struct semaphore {
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spinlock_t sentry;
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int 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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.sentry = SPIN_LOCK_UNLOCKED, \
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.count = 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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extern 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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static inline int sem_getcount(struct semaphore *sem)
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{
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return sem->count;
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}
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asmlinkage void __down(struct semaphore * sem);
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asmlinkage int __down_interruptible(struct semaphore * sem);
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asmlinkage void __up(struct semaphore * sem);
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/* Semaphores can be `tried' from irq context. So we have to disable
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* interrupts while we're messing with the semaphore. Sorry.
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*/
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extern __inline__ void down(struct semaphore * sem)
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{
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might_sleep();
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spin_lock_irq(&sem->sentry);
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if (sem->count > 0) {
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sem->count--;
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} else {
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__down(sem);
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}
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spin_unlock_irq(&sem->sentry);
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}
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extern __inline__ int down_interruptible(struct semaphore * sem)
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{
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int ret = 0;
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might_sleep();
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spin_lock_irq(&sem->sentry);
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if (sem->count > 0) {
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sem->count--;
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} else {
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ret = __down_interruptible(sem);
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}
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spin_unlock_irq(&sem->sentry);
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return ret;
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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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* May not sleep, but must preserve irq state
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*/
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extern __inline__ int down_trylock(struct semaphore * sem)
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{
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unsigned long flags;
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int count;
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spin_lock_irqsave(&sem->sentry, flags);
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count = sem->count - 1;
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if (count >= 0)
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sem->count = count;
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spin_unlock_irqrestore(&sem->sentry, flags);
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return (count < 0);
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}
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/*
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* Note! This is subtle. We jump to wake people up only if
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* the semaphore was negative (== somebody was waiting on it).
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*/
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extern __inline__ void up(struct semaphore * sem)
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{
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unsigned long flags;
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spin_lock_irqsave(&sem->sentry, flags);
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if (sem->count < 0) {
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__up(sem);
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} else {
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sem->count++;
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}
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spin_unlock_irqrestore(&sem->sentry, flags);
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}
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#endif /* _ASM_PARISC_SEMAPHORE_H */
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