[PATCH -next 4/4] cpuset: replace cpuset_lock() with guard_cpuset()

[Chen Ridong]

From: Chen Ridong <chenridong@xxxxxxxxxx>

The guard_cpuset() is introduced, we can replace all cpuset_lock()
usage with it and remove the cpuset_lock().

Signed-off-by: Chen Ridong <chenridong@xxxxxxxxxx>
---
 include/linux/cpuset.h  |  2 --
 kernel/cgroup/cpuset.c  | 10 ----------
 kernel/sched/syscalls.c | 15 +++++----------
 3 files changed, 5 insertions(+), 22 deletions(-)

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 6153de28acf0..1baf12f4be19 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -72,8 +72,6 @@ extern void cpuset_force_rebuild(void);
 extern void cpuset_update_active_cpus(void);
 extern void inc_dl_tasks_cs(struct task_struct *task);
 extern void dec_dl_tasks_cs(struct task_struct *task);
-extern void cpuset_lock(void);
-extern void cpuset_unlock(void);
 extern void guard_cpuset(void);
 extern void cpuset_cpus_allowed(struct task_struct *p, struct cpumask *mask);
 extern bool cpuset_cpus_allowed_fallback(struct task_struct *p);
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 110d2b93ff96..04ed73d0887e 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -250,16 +250,6 @@ static struct cpuset top_cpuset = {
 
 static DEFINE_MUTEX(cpuset_mutex);
 
-void cpuset_lock(void)
-{
-	mutex_lock(&cpuset_mutex);
-}
-
-void cpuset_unlock(void)
-{
-	mutex_unlock(&cpuset_mutex);
-}
-
 void guard_cpuset(void)
 {
 	guard(mutex)(&cpuset_mutex);
diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c
index 77ae87f36e84..954f6e9af41b 100644
--- a/kernel/sched/syscalls.c
+++ b/kernel/sched/syscalls.c
@@ -577,8 +577,10 @@ int __sched_setscheduler(struct task_struct *p,
 	 * information.
 	 */
 	if (dl_policy(policy) || dl_policy(p->policy)) {
-		cpuset_locked = true;
-		cpuset_lock();
+		if (!cpuset_locked) {
+			guard_cpuset();
+			cpuset_locked = true;
+		}
 	}
 
 	/*
@@ -660,8 +662,6 @@ int __sched_setscheduler(struct task_struct *p,
 	if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
 		policy = oldpolicy = -1;
 		task_rq_unlock(rq, p, &rf);
-		if (cpuset_locked)
-			cpuset_unlock();
 		goto recheck;
 	}
 
@@ -733,11 +733,8 @@ int __sched_setscheduler(struct task_struct *p,
 	head = splice_balance_callbacks(rq);
 	task_rq_unlock(rq, p, &rf);
 
-	if (pi) {
-		if (cpuset_locked)
-			cpuset_unlock();
+	if (pi)
 		rt_mutex_adjust_pi(p);
-	}
 
 	/* Run balance callbacks after we've adjusted the PI chain: */
 	balance_callbacks(rq, head);
@@ -747,8 +744,6 @@ int __sched_setscheduler(struct task_struct *p,
 
 unlock:
 	task_rq_unlock(rq, p, &rf);
-	if (cpuset_locked)
-		cpuset_unlock();
 	return retval;
 }
 
-- 
2.34.1