Merge branch 'for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq

Pull workqueue updates from Tejun Heo:
 "Nothing too interesting. Just two trivial patches"

* 'for-5.7' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
  workqueue: Mark up unlocked access to wq->first_flusher
  workqueue: Make workqueue_init*() return void

include/linux/workqueue.h

@@ -665,7 +665,7 @@ int workqueue_online_cpu(unsigned int cpu);
 int workqueue_offline_cpu(unsigned int cpu);
 #endif
 
-int __init workqueue_init_early(void);
-int __init workqueue_init(void);
+void __init workqueue_init_early(void);
+void __init workqueue_init(void);
 
 #endif

kernel/workqueue.c

@@ -2834,7 +2834,7 @@ void flush_workqueue(struct workqueue_struct *wq)
 	 * First flushers are responsible for cascading flushes and
 	 * handling overflow.  Non-first flushers can simply return.
 	 */
-	if (wq->first_flusher != &this_flusher)
+	if (READ_ONCE(wq->first_flusher) != &this_flusher)
 		return;
 
 	mutex_lock(&wq->mutex);
@@ -2843,7 +2843,7 @@ void flush_workqueue(struct workqueue_struct *wq)
 	if (wq->first_flusher != &this_flusher)
 		goto out_unlock;
 
-	wq->first_flusher = NULL;
+	WRITE_ONCE(wq->first_flusher, NULL);
 
 	WARN_ON_ONCE(!list_empty(&this_flusher.list));
 	WARN_ON_ONCE(wq->flush_color != this_flusher.flush_color);
@@ -5898,7 +5898,7 @@ static void __init wq_numa_init(void)
  * items.  Actual work item execution starts only after kthreads can be
  * created and scheduled right before early initcalls.
  */
-int __init workqueue_init_early(void)
+void __init workqueue_init_early(void)
 {
 	int std_nice[NR_STD_WORKER_POOLS] = { 0, HIGHPRI_NICE_LEVEL };
 	int hk_flags = HK_FLAG_DOMAIN | HK_FLAG_WQ;
@@ -5965,8 +5965,6 @@ int __init workqueue_init_early(void)
 	       !system_unbound_wq || !system_freezable_wq ||
 	       !system_power_efficient_wq ||
 	       !system_freezable_power_efficient_wq);
-
-	return 0;
 }
 
 /**
@@ -5978,7 +5976,7 @@ int __init workqueue_init_early(void)
  * are no kworkers executing the work items yet.  Populate the worker pools
  * with the initial workers and enable future kworker creations.
  */
-int __init workqueue_init(void)
+void __init workqueue_init(void)
 {
 	struct workqueue_struct *wq;
 	struct worker_pool *pool;
@@ -6025,6 +6023,4 @@ int __init workqueue_init(void)
 
 	wq_online = true;
 	wq_watchdog_init();
-
-	return 0;
 }