> Arnd contacted me off-list and made the very sensible suggestion of:
>
> struct completion {
> struct semaphore sem;
> }
>
> That lets us eliminate the duplicate code since all the completion
> functions become very thin wrappers around semaphore operations.
Just make sure you don't forget the history of completions... As
Linus said long ago (http://lwn.net/2001/0802/a/lt-completions.php3):
In case anybody cares, the race was that Linux semaphores only protect the
accesses _inside_ the semaphore, while the accesses by the semaphores
themselves can "race" in the internal implementation. That helps make an
efficient implementation, but it means that the race was:
cpu #1 cpu #2
DECLARE_MUTEX_LOCKED(sem);
..
down(&sem); up(&sem);
return;
wake_up(&sem.wait) /*BOOM*/
--
