sched: Change wait_for_completion_*_timeout() to return a signed long

wait_for_completion_*_timeout() can return:

   0: if the wait timed out
 -ve: if the wait was interrupted
 +ve: if the completion was completed.

As they currently return an 'unsigned long', the last two cases
are not easily distinguished which can easily result in buggy
code, as is the case for the recently added
wait_for_completion_interruptible_timeout() call in
net/sunrpc/cache.c

So change them both to return 'long'.  As MAX_SCHEDULE_TIMEOUT
is LONG_MAX, a large +ve return value should never overflow.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: J.  Bruce Fields <bfields@fieldses.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
LKML-Reference: <20110105125016.64ccab0e@notabene.brown>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 4 deletions

diff --git a/include/linux/completion.h b/include/linux/completion.h
index 36d57f74cd0..51494e6b554 100644
--- a/include/linux/completion.h
+++ b/include/linux/completion.h
@@ -81,10 +81,10 @@ extern int wait_for_completion_interruptible(struct completion *x);
 extern int wait_for_completion_killable(struct completion *x);
 extern unsigned long wait_for_completion_timeout(struct completion *x,
                                                    unsigned long timeout);
-extern unsigned long wait_for_completion_interruptible_timeout(
-                        struct completion *x, unsigned long timeout);
-extern unsigned long wait_for_completion_killable_timeout(
-                        struct completion *x, unsigned long timeout);
+extern long wait_for_completion_interruptible_timeout(
+        struct completion *x, unsigned long timeout);
+extern long wait_for_completion_killable_timeout(
+        struct completion *x, unsigned long timeout);
 extern bool try_wait_for_completion(struct completion *x);
 extern bool completion_done(struct completion *x);