diff options
author | Matthew Wilcox <matthew@wil.cx> | 2008-03-07 21:55:58 -0500 |
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committer | Matthew Wilcox <willy@linux.intel.com> | 2008-04-17 10:42:34 -0400 |
commit | 64ac24e738823161693bf791f87adc802cf529ff (patch) | |
tree | 19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-parisc/semaphore-helper.h | |
parent | e48b3deee475134585eed03e7afebe4bf9e0dba9 (diff) |
Generic semaphore implementation
Semaphores are no longer performance-critical, so a generic C
implementation is better for maintainability, debuggability and
extensibility. Thanks to Peter Zijlstra for fixing the lockdep
warning. Thanks to Harvey Harrison for pointing out that the
unlikely() was unnecessary.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-parisc/semaphore-helper.h')
-rw-r--r-- | include/asm-parisc/semaphore-helper.h | 89 |
1 files changed, 0 insertions, 89 deletions
diff --git a/include/asm-parisc/semaphore-helper.h b/include/asm-parisc/semaphore-helper.h deleted file mode 100644 index 387f7c1277a..00000000000 --- a/include/asm-parisc/semaphore-helper.h +++ /dev/null @@ -1,89 +0,0 @@ -#ifndef _ASM_PARISC_SEMAPHORE_HELPER_H -#define _ASM_PARISC_SEMAPHORE_HELPER_H - -/* - * SMP- and interrupt-safe semaphores helper functions. - * - * (C) Copyright 1996 Linus Torvalds - * (C) Copyright 1999 Andrea Arcangeli - */ - -/* - * These two _must_ execute atomically wrt each other. - * - * This is trivially done with load_locked/store_cond, - * which we have. Let the rest of the losers suck eggs. - */ -static __inline__ void wake_one_more(struct semaphore * sem) -{ - atomic_inc((atomic_t *)&sem->waking); -} - -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 atomic 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_trylock: - * 1 failed to lock - * 0 got the lock - * - * We must undo the sem->count down_trylock() increment while we are - * protected by the spinlock in order to make atomic 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 /* _ASM_PARISC_SEMAPHORE_HELPER_H */ |