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authorMatthew Wilcox <matthew@wil.cx>2008-03-07 21:55:58 -0500
committerMatthew Wilcox <willy@linux.intel.com>2008-04-17 10:42:34 -0400
commit64ac24e738823161693bf791f87adc802cf529ff (patch)
tree19c0b0cf314d4394ca580c05b86cdf874ce0a167 /include/asm-sh/semaphore-helper.h
parente48b3deee475134585eed03e7afebe4bf9e0dba9 (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-sh/semaphore-helper.h')
-rw-r--r--include/asm-sh/semaphore-helper.h89
1 files changed, 0 insertions, 89 deletions
diff --git a/include/asm-sh/semaphore-helper.h b/include/asm-sh/semaphore-helper.h
deleted file mode 100644
index bd8230c369c..00000000000
--- a/include/asm-sh/semaphore-helper.h
+++ /dev/null
@@ -1,89 +0,0 @@
-#ifndef __ASM_SH_SEMAPHORE_HELPER_H
-#define __ASM_SH_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->sleepers);
-}
-
-static __inline__ int waking_non_zero(struct semaphore *sem)
-{
- unsigned long flags;
- int ret = 0;
-
- spin_lock_irqsave(&semaphore_wake_lock, flags);
- if (sem->sleepers > 0) {
- sem->sleepers--;
- 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->sleepers > 0) {
- sem->sleepers--;
- 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->sleepers <= 0)
- atomic_inc(&sem->count);
- else {
- sem->sleepers--;
- ret = 0;
- }
- spin_unlock_irqrestore(&semaphore_wake_lock, flags);
- return ret;
-}
-
-#endif /* __ASM_SH_SEMAPHORE_HELPER_H */