sched/deadline: Change return value of cpudl_find()

cpudl_find() users are only interested in knowing if suitable CPU(s)
were found or not (and then they look at later_mask to know which).

Change cpudl_find() return type accordingly. Aligns with rt code.

Signed-off-by: Byungchul Park <byungchul.park@lge.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <bristot@redhat.com>
Cc: <juri.lelli@gmail.com>
Cc: <kernel-team@lge.com>
Cc: <rostedt@goodmis.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1495504859-10960-3-git-send-email-byungchul.park@lge.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/cpudeadline.c

@@ -119,29 +119,29 @@ static inline int cpudl_maximum(struct cpudl *cp)
  * @p: the task
  * @later_mask: a mask to fill in with the selected CPUs (or NULL)
  *
- * Returns: int - best CPU (heap maximum if suitable)
+ * Returns: int - CPUs were found
  */
 int cpudl_find(struct cpudl *cp, struct task_struct *p,
 	       struct cpumask *later_mask)
 {
-	int best_cpu = -1;
 	const struct sched_dl_entity *dl_se = &p->dl;
 
 	if (later_mask &&
 	    cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
-		best_cpu = cpumask_any(later_mask);
-		goto out;
-	} else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
-			dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
-		best_cpu = cpudl_maximum(cp);
-		if (later_mask)
-			cpumask_set_cpu(best_cpu, later_mask);
-	}
+		return 1;
+	} else {
+		int best_cpu = cpudl_maximum(cp);
+		WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
 
-out:
-	WARN_ON(best_cpu != -1 && !cpu_present(best_cpu));
+		if (cpumask_test_cpu(best_cpu, &p->cpus_allowed) &&
+		    dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
+			if (later_mask)
+				cpumask_set_cpu(best_cpu, later_mask);
 
-	return best_cpu;
+			return 1;
+		}
+	}
+	return 0;
 }
 
 /*

kernel/sched/deadline.c

@@ -1594,7 +1594,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
 	 * let's hope p can move out.
 	 */
 	if (rq->curr->nr_cpus_allowed == 1 ||
-	    cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1)
+	    !cpudl_find(&rq->rd->cpudl, rq->curr, NULL))
 		return;
 
 	/*
@@ -1602,7 +1602,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
 	 * see if it is pushed or pulled somewhere else.
 	 */
 	if (p->nr_cpus_allowed != 1 &&
-	    cpudl_find(&rq->rd->cpudl, p, NULL) != -1)
+	    cpudl_find(&rq->rd->cpudl, p, NULL))
 		return;
 
 	resched_curr(rq);
@@ -1811,7 +1811,7 @@ static int find_later_rq(struct task_struct *task)
 	 * We have to consider system topology and task affinity
 	 * first, then we can look for a suitable cpu.
 	 */
-	if (cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask) == -1)
+	if (!cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask))
 		return -1;
 
 	/*