Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | #ifndef _H8300_SEMAPHORE_HELPER_H |
| 2 | #define _H8300_SEMAPHORE_HELPER_H |
| 3 | |
| 4 | /* |
| 5 | * SMP- and interrupt-safe semaphores helper functions. |
| 6 | * |
| 7 | * (C) Copyright 1996 Linus Torvalds |
| 8 | * |
| 9 | * based on |
| 10 | * m68k version by Andreas Schwab |
| 11 | */ |
| 12 | |
| 13 | #include <linux/config.h> |
| 14 | #include <linux/errno.h> |
| 15 | |
| 16 | /* |
| 17 | * These two _must_ execute atomically wrt each other. |
| 18 | */ |
| 19 | static inline void wake_one_more(struct semaphore * sem) |
| 20 | { |
| 21 | atomic_inc((atomic_t *)&sem->sleepers); |
| 22 | } |
| 23 | |
| 24 | static inline int waking_non_zero(struct semaphore *sem) |
| 25 | { |
| 26 | int ret; |
| 27 | unsigned long flags; |
| 28 | |
| 29 | spin_lock_irqsave(&semaphore_wake_lock, flags); |
| 30 | ret = 0; |
| 31 | if (sem->sleepers > 0) { |
| 32 | sem->sleepers--; |
| 33 | ret = 1; |
| 34 | } |
| 35 | spin_unlock_irqrestore(&semaphore_wake_lock, flags); |
| 36 | return ret; |
| 37 | } |
| 38 | |
| 39 | /* |
| 40 | * waking_non_zero_interruptible: |
| 41 | * 1 got the lock |
| 42 | * 0 go to sleep |
| 43 | * -EINTR interrupted |
| 44 | */ |
| 45 | static inline int waking_non_zero_interruptible(struct semaphore *sem, |
| 46 | struct task_struct *tsk) |
| 47 | { |
| 48 | int ret; |
| 49 | unsigned long flags; |
| 50 | |
| 51 | spin_lock_irqsave(&semaphore_wake_lock, flags); |
| 52 | ret = 0; |
| 53 | if (sem->sleepers > 0) { |
| 54 | sem->sleepers--; |
| 55 | ret = 1; |
| 56 | } else if (signal_pending(tsk)) { |
| 57 | atomic_inc(&sem->count); |
| 58 | ret = -EINTR; |
| 59 | } |
| 60 | spin_unlock_irqrestore(&semaphore_wake_lock, flags); |
| 61 | return ret; |
| 62 | } |
| 63 | |
| 64 | /* |
| 65 | * waking_non_zero_trylock: |
| 66 | * 1 failed to lock |
| 67 | * 0 got the lock |
| 68 | */ |
| 69 | static inline int waking_non_zero_trylock(struct semaphore *sem) |
| 70 | { |
| 71 | int ret; |
| 72 | unsigned long flags; |
| 73 | |
| 74 | spin_lock_irqsave(&semaphore_wake_lock, flags); |
| 75 | ret = 1; |
| 76 | if (sem->sleepers <= 0) |
| 77 | atomic_inc(&sem->count); |
| 78 | else { |
| 79 | sem->sleepers--; |
| 80 | ret = 0; |
| 81 | } |
| 82 | spin_unlock_irqrestore(&semaphore_wake_lock, flags); |
| 83 | return ret; |
| 84 | } |
| 85 | |
| 86 | #endif |