[RFC 3/4] workqueue: reap dead pool workqueue on queuing work

[Hillf Danton <hdanton@xxxxxxxx>]

Release rcu lock to reap dead pool workqueue.

Signed-off-by: Hillf Danton <hdanton@xxxxxxxx>
---

--- d/kernel/workqueue.c
+++ e/kernel/workqueue.c
@@ -1409,9 +1409,9 @@ static void __queue_work(int cpu, struct
 	if (unlikely(wq->flags & __WQ_DRAINING) &&
 	    WARN_ON_ONCE(!is_chained_work(wq)))
 		return;
-
-	rcu_read_lock();
 retry:
+	rcu_read_lock();
+
 	/* pwq which will be used unless @work is executing elsewhere */
 	if (wq->flags & WQ_UNBOUND) {
 		if (req_cpu == WORK_CPU_UNBOUND)
@@ -1458,6 +1458,7 @@ retry:
 	if (unlikely(!pwq->refcnt)) {
 		if (wq->flags & WQ_UNBOUND) {
 			spin_unlock(&pwq->pool->lock);
+			rcu_read_unlock();
 			cpu_relax();
 			goto retry;
 		}