Introduce down_try() I planned on removing the much-disliked down_trylock() (with its backwards return codes) in 2.6.27, but it's creating something of a logjam with other patches in -mm and linux-next. Andrew suggested introducing "down_try" as a wrapper now, to make the transition easier. Signed-off-by: Rusty Russell Cc: Andrew Morton Cc: Christoph Hellwig Cc: Matthew Wilcox Cc: Stephen Rothwell --- include/linux/semaphore.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff -r 92664ae4130b include/linux/semaphore.h --- a/include/linux/semaphore.h Wed May 21 14:54:40 2008 +1000 +++ b/include/linux/semaphore.h Wed May 21 15:07:31 2008 +1000 @@ -48,4 +48,18 @@ extern int __must_check down_timeout(str extern int __must_check down_timeout(struct semaphore *sem, long jiffies); extern void up(struct semaphore *sem); +/** + * down_try - try to down a semaphore, but don't block + * @sem: the semaphore + * + * This is equivalent to down_trylock(), but has the same return codes as + * spin_trylock and mutex_trylock: 1 if semaphore acquired, 0 if not. + * + * down_trylock() with its confusing return codes will be deprecated + * soon. It will not be missed. + */ +static inline bool __must_check down_try(struct semaphore *sem) +{ + return !down_trylock(sem); +} #endif /* __LINUX_SEMAPHORE_H */