add trydown
Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>
diff -r a66bdc82d8fa extras/mini-os/include/semaphore.h
--- a/extras/mini-os/include/semaphore.h Wed Jan 16 11:44:41 2008 +0000
+++ b/extras/mini-os/include/semaphore.h Thu Jan 17 12:29:01 2008 +0000
@@ -49,6 +49,19 @@ static inline void init_SEMAPHORE(struct
#define init_MUTEX(sem) init_SEMAPHORE(sem, 1)
+static inline int trydown(struct semaphore *sem)
+{
+ unsigned long flags;
+ int ret = 0;
+ local_irq_save(flags);
+ if (sem->count > 0) {
+ ret = 1;
+ sem->count--;
+ }
+ local_irq_restore(flags);
+ return ret;
+}
+
static void inline down(struct semaphore *sem)
{
unsigned long flags;
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