workqueue: Make send_mayday() take a PWQ argument directly

Make send_mayday() operate on a PWQ directly instead of taking a work
item, so that rescuer_thread() now calls send_mayday(pwq) instead of
open-coding the mayday list manipulation.

Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: Lai Jiangshan

kernel/workqueue.c

@@ -2976,9 +2976,8 @@ static void idle_cull_fn(struct work_struct *work)
 	reap_dying_workers(&cull_list);
 }
 
-static void send_mayday(struct work_struct *work)
+static void send_mayday(struct pool_workqueue *pwq)
 {
-	struct pool_workqueue *pwq = get_work_pwq(work);
 	struct workqueue_struct *wq = pwq->wq;
 
 	lockdep_assert_held(&wq_mayday_lock);
@@ -3016,7 +3015,7 @@ static void pool_mayday_timeout(struct timer_list *t)
 		 * rescuers.
 		 */
 		list_for_each_entry(work, &pool->worklist, entry)
-			send_mayday(work);
+			send_mayday(get_work_pwq(work));
 	}
 
 	raw_spin_unlock(&wq_mayday_lock);
@@ -3538,13 +3537,7 @@ static int rescuer_thread(void *__rescuer)
 			 */
 			if (pwq->nr_active && need_to_create_worker(pool)) {
 				raw_spin_lock(&wq_mayday_lock);
-				/*
-				 * Queue iff somebody else hasn't queued it already.
-				 */
-				if (list_empty(&pwq->mayday_node)) {
-					get_pwq(pwq);
-					list_add_tail(&pwq->mayday_node, &wq->maydays);
-				}
+				send_mayday(pwq);
 				raw_spin_unlock(&wq_mayday_lock);
 			}
 		}