sched: Remove sched_set_*() return value

Ingo suggested that since the new sched_set_*() functions are
implemented using the 'nocheck' variants, they really shouldn't ever
fail, so remove the return value.

Cc: axboe@kernel.dk
Cc: daniel.lezcano@linaro.org
Cc: sudeep.holla@arm.com
Cc: airlied@redhat.com
Cc: broonie@kernel.org
Cc: paulmck@kernel.org
Suggested-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

@@ -5183,30 +5183,30 @@ int sched_setscheduler_nocheck(struct task_struct *p, int policy,
  * The administrator _MUST_ configure the system, the kernel simply doesn't
  * know enough information to make a sensible choice.
  */
-int sched_set_fifo(struct task_struct *p)
+void sched_set_fifo(struct task_struct *p)
 {
 	struct sched_param sp = { .sched_priority = MAX_RT_PRIO / 2 };
-	return sched_setscheduler_nocheck(p, SCHED_FIFO, &sp);
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
 }
 EXPORT_SYMBOL_GPL(sched_set_fifo);
 
 /*
  * For when you don't much care about FIFO, but want to be above SCHED_NORMAL.
  */
-int sched_set_fifo_low(struct task_struct *p)
+void sched_set_fifo_low(struct task_struct *p)
 {
 	struct sched_param sp = { .sched_priority = 1 };
-	return sched_setscheduler_nocheck(p, SCHED_FIFO, &sp);
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
 }
 EXPORT_SYMBOL_GPL(sched_set_fifo_low);
 
-int sched_set_normal(struct task_struct *p, int nice)
+void sched_set_normal(struct task_struct *p, int nice)
 {
 	struct sched_attr attr = {
 		.sched_policy = SCHED_NORMAL,
 		.sched_nice = nice,
 	};
-	return sched_setattr_nocheck(p, &attr);
+	WARN_ON_ONCE(sched_setattr_nocheck(p, &attr) != 0);
 }
 EXPORT_SYMBOL_GPL(sched_set_normal);