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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 | #ifndef _PPC64_SEMAPHORE_H #define _PPC64_SEMAPHORE_H /* * Remove spinlock-based RW semaphores; RW semaphore definitions are * now in rwsem.h and we use the generic lib/rwsem.c implementation. * Rework semaphores to use atomic_dec_if_positive. * -- Paul Mackerras (paulus@samba.org) */ #ifdef __KERNEL__ #include <asm/atomic.h> #include <asm/system.h> #include <linux/wait.h> #include <linux/rwsem.h> struct semaphore { /* * Note that any negative value of count is equivalent to 0, * but additionally indicates that some process(es) might be * sleeping on `wait'. */ atomic_t count; wait_queue_head_t wait; #if WAITQUEUE_DEBUG long __magic; #endif }; #if WAITQUEUE_DEBUG # define __SEM_DEBUG_INIT(name) \ , (long)&(name).__magic #else # define __SEM_DEBUG_INIT(name) #endif #define __SEMAPHORE_INITIALIZER(name, count) \ { ATOMIC_INIT(count), \ __WAIT_QUEUE_HEAD_INITIALIZER((name).wait) \ __SEM_DEBUG_INIT(name) } #define __MUTEX_INITIALIZER(name) \ __SEMAPHORE_INITIALIZER(name, 1) #define __DECLARE_SEMAPHORE_GENERIC(name, count) \ struct semaphore name = __SEMAPHORE_INITIALIZER(name,count) #define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1) #define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name, 0) static inline void sema_init (struct semaphore *sem, int val) { atomic_set(&sem->count, val); init_waitqueue_head(&sem->wait); #if WAITQUEUE_DEBUG sem->__magic = (long)&sem->__magic; #endif } static inline void init_MUTEX (struct semaphore *sem) { sema_init(sem, 1); } static inline void init_MUTEX_LOCKED (struct semaphore *sem) { sema_init(sem, 0); } extern void __down(struct semaphore * sem); extern int __down_interruptible(struct semaphore * sem); extern void __up(struct semaphore * sem); static inline void down(struct semaphore * sem) { #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif /* * Try to get the semaphore, take the slow path if we fail. */ if (atomic_dec_return(&sem->count) < 0) __down(sem); smp_wmb(); } static inline int down_interruptible(struct semaphore * sem) { int ret = 0; #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif if (atomic_dec_return(&sem->count) < 0) ret = __down_interruptible(sem); smp_wmb(); return ret; } static inline int down_trylock(struct semaphore * sem) { int ret; #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif ret = atomic_dec_if_positive(&sem->count) < 0; smp_wmb(); return ret; } static inline void up(struct semaphore * sem) { #if WAITQUEUE_DEBUG CHECK_MAGIC(sem->__magic); #endif smp_wmb(); if (atomic_inc_return(&sem->count) <= 0) __up(sem); } static inline int sem_getcount(struct semaphore *sem) { return atomic_read(&sem->count); } #endif /* __KERNEL__ */ #endif /* !(_PPC64_SEMAPHORE_H) */ |