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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>
133 lines
3.1 KiB
C
133 lines
3.1 KiB
C
/* $Id: semaphore.h,v 1.3 2001/05/08 13:54:09 bjornw Exp $ */
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/* On the i386 these are coded in asm, perhaps we should as well. Later.. */
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#ifndef _CRIS_SEMAPHORE_H
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#define _CRIS_SEMAPHORE_H
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#define RW_LOCK_BIAS 0x01000000
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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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#include <asm/system.h>
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#include <asm/atomic.h>
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/*
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* CRIS semaphores, implemented in C-only so far.
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*/
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struct semaphore {
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atomic_t count;
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atomic_t waking;
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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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.waking = ATOMIC_INIT(0), \
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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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*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);
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extern int __down_interruptible(struct semaphore * sem);
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extern int __down_trylock(struct semaphore * sem);
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extern void __up(struct semaphore * sem);
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/* notice - we probably can do cli/sti here instead of saving */
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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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int failed;
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might_sleep();
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/* atomically decrement the semaphores count, and if its negative, we wait */
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cris_atomic_save(sem, flags);
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failed = --(sem->count.counter) < 0;
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cris_atomic_restore(sem, flags);
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if(failed) {
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__down(sem);
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}
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}
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/*
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* This version waits in interruptible state so that the waiting
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* process can be killed. The down_interruptible routine
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* returns negative for signalled and zero for semaphore acquired.
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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 failed;
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might_sleep();
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/* atomically decrement the semaphores count, and if its negative, we wait */
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cris_atomic_save(sem, flags);
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failed = --(sem->count.counter) < 0;
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cris_atomic_restore(sem, flags);
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if(failed)
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failed = __down_interruptible(sem);
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return(failed);
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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 failed;
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cris_atomic_save(sem, flags);
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failed = --(sem->count.counter) < 0;
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cris_atomic_restore(sem, flags);
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if(failed)
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failed = __down_trylock(sem);
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return(failed);
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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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* The default case (no contention) will result in NO
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* jumps for both down() and up().
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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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int wakeup;
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/* atomically increment the semaphores count, and if it was negative, we wake people */
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cris_atomic_save(sem, flags);
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wakeup = ++(sem->count.counter) <= 0;
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cris_atomic_restore(sem, flags);
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if(wakeup) {
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__up(sem);
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}
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}
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#endif
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