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>
109 lines
2.6 KiB
C
109 lines
2.6 KiB
C
/*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* Copyright (C) 1996 Linus Torvalds
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* Copyright (C) 1998, 99, 2000, 01, 04 Ralf Baechle
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* Copyright (C) 1999, 2000, 01 Silicon Graphics, Inc.
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* Copyright (C) 2000, 01 MIPS Technologies, Inc.
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*
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* In all honesty, little of the old MIPS code left - the PPC64 variant was
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* just looking nice and portable so I ripped it. Credits to whoever wrote
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* it.
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*/
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#ifndef __ASM_SEMAPHORE_H
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#define __ASM_SEMAPHORE_H
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/*
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* Remove spinlock-based RW semaphores; RW semaphore definitions are
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* now in rwsem.h and we use the generic lib/rwsem.c implementation.
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* Rework semaphores to use atomic_dec_if_positive.
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* -- Paul Mackerras (paulus@samba.org)
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*/
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#ifdef __KERNEL__
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#include <asm/atomic.h>
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#include <asm/system.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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/*
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* Note that any negative value of count is equivalent to 0,
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* but additionally indicates that some process(es) might be
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* sleeping on `wait'.
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*/
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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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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 * sem);
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extern int __down_interruptible(struct semaphore * sem);
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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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might_sleep();
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/*
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* Try to get the semaphore, take the slow path if we fail.
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*/
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if (unlikely(atomic_dec_return(&sem->count) < 0))
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__down(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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int ret = 0;
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might_sleep();
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if (unlikely(atomic_dec_return(&sem->count) < 0))
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ret = __down_interruptible(sem);
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return ret;
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}
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static inline int down_trylock(struct semaphore * sem)
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{
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return atomic_dec_if_positive(&sem->count) < 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(sem);
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}
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#endif /* __KERNEL__ */
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#endif /* __ASM_SEMAPHORE_H */
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