sched/wait: Collapse __wait_event_hrtimeout()

While not a whole-sale replacement like the others we can still reduce
the size of __wait_event_hrtimeout() considerably by noting that the
actual core of __wait_event_hrtimeout() is identical to what
___wait_event() generates.

Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20131002092528.972793648@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

include/linux/wait.h

@@ -337,7 +337,6 @@ do {									\
 #define __wait_event_hrtimeout(wq, condition, timeout, state)		\
 ({									\
 	int __ret = 0;							\
-	DEFINE_WAIT(__wait);						\
 	struct hrtimer_sleeper __t;					\
 									\
 	hrtimer_init_on_stack(&__t.timer, CLOCK_MONOTONIC,		\
@@ -348,25 +347,15 @@ do {									\
 				       current->timer_slack_ns,		\
 				       HRTIMER_MODE_REL);		\
 									\
-	for (;;) {							\
-		prepare_to_wait(&wq, &__wait, state);			\
-		if (condition)						\
-			break;						\
-		if (state == TASK_INTERRUPTIBLE &&			\
-		    signal_pending(current)) {				\
-			__ret = -ERESTARTSYS;				\
-			break;						\
-		}							\
+	___wait_event(wq, condition, state, 0, __ret,			\
 		if (!__t.task) {					\
 			__ret = -ETIME;					\
 			break;						\
 		}							\
-		schedule();						\
-	}								\
+		schedule());						\
 									\
 	hrtimer_cancel(&__t.timer);					\
 	destroy_hrtimer_on_stack(&__t.timer);				\
-	finish_wait(&wq, &__wait);					\
 	__ret;								\
 })