[PATCH 4/6] futex: Use current->time_slack_ns for rt tasks too

[Darren Hart <dvhltc@us.ibm.com>]

RT tasks should set their timer slack to 0 on their own.  This patch removes
the 'if (rt_task()) slack = 0;' block in futex_wait.

Build and boot tested on a 4 way Intel x86_64 workstation.  Passes basic
pthread_mutex and PI tests out of ltp/testcases/realtime.

Signed-off-by: Darren Hart <dvhltc@us.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Rusty Russell <rusty@rustcorp.com.au>
---

 kernel/futex.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/kernel/futex.c b/kernel/futex.c
index e149545..6579912 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -1253,16 +1253,13 @@ retry:
 		if (!abs_time)
 			schedule();
 		else {
-			unsigned long slack;
-			slack = current->timer_slack_ns;
-			if (rt_task(current))
-				slack = 0;
 			hrtimer_init_on_stack(&t.timer,
 					      clockrt ? CLOCK_REALTIME :
 					      CLOCK_MONOTONIC,
 					      HRTIMER_MODE_ABS);
 			hrtimer_init_sleeper(&t, current);
-			hrtimer_set_expires_range_ns(&t.timer, *abs_time, slack);
+			hrtimer_set_expires_range_ns(&t.timer, *abs_time,
+						     current->timer_slack_ns);
 
 			hrtimer_start_expires(&t.timer, HRTIMER_MODE_ABS);
 			if (!hrtimer_active(&t.timer))