From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- include/asm-arm26/semaphore-helper.h | 84 ++++++++++++++++++++++++++++++++++++ 1 file changed, 84 insertions(+) create mode 100644 include/asm-arm26/semaphore-helper.h (limited to 'include/asm-arm26/semaphore-helper.h') diff --git a/include/asm-arm26/semaphore-helper.h b/include/asm-arm26/semaphore-helper.h new file mode 100644 index 000000000000..1d7f1987edb9 --- /dev/null +++ b/include/asm-arm26/semaphore-helper.h @@ -0,0 +1,84 @@ +#ifndef ASMARM_SEMAPHORE_HELPER_H +#define ASMARM_SEMAPHORE_HELPER_H + +/* + * These two _must_ execute atomically wrt each other. + */ +static inline void wake_one_more(struct semaphore * sem) +{ + unsigned long flags; + + spin_lock_irqsave(&semaphore_wake_lock, flags); + if (atomic_read(&sem->count) <= 0) + sem->waking++; + spin_unlock_irqrestore(&semaphore_wake_lock, flags); +} + +static inline int waking_non_zero(struct semaphore *sem) +{ + unsigned long flags; + int ret = 0; + + spin_lock_irqsave(&semaphore_wake_lock, flags); + if (sem->waking > 0) { + sem->waking--; + ret = 1; + } + spin_unlock_irqrestore(&semaphore_wake_lock, flags); + return ret; +} + +/* + * waking non zero interruptible + * 1 got the lock + * 0 go to sleep + * -EINTR interrupted + * + * We must undo the sem->count down_interruptible() increment while we are + * protected by the spinlock in order to make this atomic_inc() with the + * atomic_read() in wake_one_more(), otherwise we can race. -arca + */ +static inline int waking_non_zero_interruptible(struct semaphore *sem, + struct task_struct *tsk) +{ + unsigned long flags; + int ret = 0; + + spin_lock_irqsave(&semaphore_wake_lock, flags); + if (sem->waking > 0) { + sem->waking--; + ret = 1; + } else if (signal_pending(tsk)) { + atomic_inc(&sem->count); + ret = -EINTR; + } + spin_unlock_irqrestore(&semaphore_wake_lock, flags); + return ret; +} + +/* + * waking_non_zero_try_lock: + * 1 failed to lock + * 0 got the lock + * + * We must undo the sem->count down_interruptible() increment while we are + * protected by the spinlock in order to make this atomic_inc() with the + * atomic_read() in wake_one_more(), otherwise we can race. -arca + */ +static inline int waking_non_zero_trylock(struct semaphore *sem) +{ + unsigned long flags; + int ret = 1; + + spin_lock_irqsave(&semaphore_wake_lock, flags); + if (sem->waking <= 0) + atomic_inc(&sem->count); + else { + sem->waking--; + ret = 0; + } + spin_unlock_irqrestore(&semaphore_wake_lock, flags); + return ret; +} + +#endif -- cgit v1.2.3