/*
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/*
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* FILE: semaphore.c
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* FILE: semaphore.c
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* AUTHOR: kma@cse.ogi.edu
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* AUTHOR: kma@cse.ogi.edu
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* DESCR: interrupt-safe i960 semaphore implementation; isn't ready for SMP
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* DESCR: interrupt-safe i960 semaphore implementation; isn't ready for SMP
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*/
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*/
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#include <asm/semaphore.h>
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#include <asm/semaphore.h>
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#include <linux/sched.h>
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#include <linux/sched.h>
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extern int __down_common(struct semaphore* sem, int intrflag)
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extern int __down_common(struct semaphore* sem, int intrflag)
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{
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{
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long flags;
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long flags;
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int retval=0;
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int retval=0;
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save_flags(flags);
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save_flags(flags);
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cli();
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cli();
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if (--sem->count < 0) {
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if (--sem->count < 0) {
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if (intrflag) {
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if (intrflag) {
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interruptible_sleep_on(&sem->wait);
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interruptible_sleep_on(&sem->wait);
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if (current->signal & ~current->blocked) {
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if (current->signal & ~current->blocked) {
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retval = -1;
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retval = -1;
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}
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}
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}
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}
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else
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else
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sleep_on(&sem->wait);
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sleep_on(&sem->wait);
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}
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}
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restore_flags(flags);
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restore_flags(flags);
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return retval;
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return retval;
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}
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}
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void down(struct semaphore * sem)
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void down(struct semaphore * sem)
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{
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{
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__down_common(sem, 0);
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__down_common(sem, 0);
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}
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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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* This version waits in interruptible state so that the waiting
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* process can be killed. The down_failed_interruptible routine
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* process can be killed. The down_failed_interruptible routine
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* returns negative for signalled and zero for semaphore acquired.
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* returns negative for signalled and zero for semaphore acquired.
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*/
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*/
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extern int down_interruptible(struct semaphore * sem)
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extern int down_interruptible(struct semaphore * sem)
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{
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{
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return __down_common(sem, 1);
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return __down_common(sem, 1);
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return 0;
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return 0;
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}
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}
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/*
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/*
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* Primitives to spin on a lock. Needed only for SMP.
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* Primitives to spin on a lock. Needed only for SMP.
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*/
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*/
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extern void get_buzz_lock(int *lock_ptr)
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extern void get_buzz_lock(int *lock_ptr)
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{
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{
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#ifdef __SMP__
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#ifdef __SMP__
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while (xchg(lock_ptr,1) != 0) ;
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while (xchg(lock_ptr,1) != 0) ;
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#endif
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#endif
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}
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}
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extern void give_buzz_lock(int *lock_ptr)
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extern void give_buzz_lock(int *lock_ptr)
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{
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{
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#ifdef __SMP__
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#ifdef __SMP__
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*lock_ptr = 0 ;
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*lock_ptr = 0 ;
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#endif
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#endif
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}
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}
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/*
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/*
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* We wake people up only if the semaphore was negative (== somebody was
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* We wake people up only if the semaphore was negative (== somebody was
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* waiting on it).
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* waiting on it).
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*/
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*/
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extern void up(struct semaphore * sem)
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extern void up(struct semaphore * sem)
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{
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{
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long flags;
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long flags;
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save_flags(flags);
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save_flags(flags);
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cli();
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cli();
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if (sem->count++ < 0)
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if (sem->count++ < 0)
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wake_up(&sem->wait);
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wake_up(&sem->wait);
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restore_flags(flags);
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restore_flags(flags);
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}
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}
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