sched/core: Streamle calls to task_rq_unlock()

Calls to task_rq_unlock() are done several times in the
__sched_setscheduler() function.  This is fine when only the rq lock needs to be
handled but not so much when other locks come into play.

This patch streamlines the release of the rq lock so that only one
location need to be modified when dealing with more than one lock.

No change of functionality is introduced by this patch.

Tested-by: Dietmar Eggemann <[email protected]>
Signed-off-by: Mathieu Poirier <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Reviewed-by: Steven Rostedt (VMware) <[email protected]>
Acked-by: Tejun Heo <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 14 insertions, 10 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0b22e55cebe8..1af3d2dc6b29 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -4712,8 +4712,8 @@ recheck:
 	 * Changing the policy of the stop threads its a very bad idea:
 	 */
 	if (p == rq->stop) {
-		task_rq_unlock(rq, p, &rf);
-		return -EINVAL;
+		retval = -EINVAL;
+		goto unlock;
 	}
 
 	/*
@@ -4731,8 +4731,8 @@ recheck:
 			goto change;
 
 		p->sched_reset_on_fork = reset_on_fork;
-		task_rq_unlock(rq, p, &rf);
-		return 0;
+		retval = 0;
+		goto unlock;
 	}
 change:
 
@@ -4745,8 +4745,8 @@ change:
 		if (rt_bandwidth_enabled() && rt_policy(policy) &&
 				task_group(p)->rt_bandwidth.rt_runtime == 0 &&
 				!task_group_is_autogroup(task_group(p))) {
-			task_rq_unlock(rq, p, &rf);
-			return -EPERM;
+			retval = -EPERM;
+			goto unlock;
 		}
 #endif
 #ifdef CONFIG_SMP
@@ -4761,8 +4761,8 @@ change:
 			 */
 			if (!cpumask_subset(span, p->cpus_ptr) ||
 			    rq->rd->dl_bw.bw == 0) {
-				task_rq_unlock(rq, p, &rf);
-				return -EPERM;
+				retval = -EPERM;
+				goto unlock;
 			}
 		}
 #endif
@@ -4781,8 +4781,8 @@ change:
 	 * is available.
 	 */
 	if ((dl_policy(policy) || dl_task(p)) && sched_dl_overflow(p, policy, attr)) {
-		task_rq_unlock(rq, p, &rf);
-		return -EBUSY;
+		retval = -EBUSY;
+		goto unlock;
 	}
 
 	p->sched_reset_on_fork = reset_on_fork;
@@ -4840,6 +4840,10 @@ change:
 	preempt_enable();
 
 	return 0;
+
+unlock:
+	task_rq_unlock(rq, p, &rf);
+	return retval;
 }
 
 static int _sched_setscheduler(struct task_struct *p, int policy,