[PATCH] sched: fix SCHED_FIFO bug in sys_sched_rr_get_interval()

The introduction of SCHED_BATCH scheduling class with a value of 3 means
that the expression (p->policy & SCHED_FIFO) will return true if policy
is SCHED_BATCH or SCHED_FIFO.

Unfortunately, this expression is used in sys_sched_rr_get_interval()
and in the absence of a comment to say that this is intentional I
presume that it is unintentional and erroneous.

The fix is to change the expression to (p->policy == SCHED_FIFO).
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

kernel/sched.c

@@ -4247,7 +4247,7 @@ long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
 	if (retval)
 		goto out_unlock;
 
-	jiffies_to_timespec(p->policy & SCHED_FIFO ?
+	jiffies_to_timespec(p->policy == SCHED_FIFO ?
 				0 : task_timeslice(p), &t);
 	read_unlock(&tasklist_lock);
 	retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;