workqueue: fix max_active handling in init_and_link_pwq()
Since 9e8cd2f589 ("workqueue: implement apply_workqueue_attrs()"),
init_and_link_pwq() may be called to initialize a new pool_workqueue
for a workqueue which is already online, but the function was setting
pwq->max_active to wq->saved_max_active without proper
synchronization.
Fix it by calling pwq_adjust_max_active() under proper locking instead
of manually setting max_active.
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 9e2ec4c..7567614 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3771,21 +3771,25 @@
pwq->wq = wq;
pwq->flush_color = -1;
pwq->refcnt = 1;
- pwq->max_active = wq->saved_max_active;
INIT_LIST_HEAD(&pwq->delayed_works);
INIT_LIST_HEAD(&pwq->mayday_node);
INIT_WORK(&pwq->unbound_release_work, pwq_unbound_release_workfn);
- /*
- * Link @pwq and set the matching work_color. This is synchronized
- * with flush_mutex to avoid confusing flush_workqueue().
- */
mutex_lock(&wq->flush_mutex);
spin_lock_irq(&workqueue_lock);
+ /*
+ * Set the matching work_color. This is synchronized with
+ * flush_mutex to avoid confusing flush_workqueue().
+ */
if (p_last_pwq)
*p_last_pwq = first_pwq(wq);
pwq->work_color = wq->work_color;
+
+ /* sync max_active to the current setting */
+ pwq_adjust_max_active(pwq);
+
+ /* link in @pwq */
list_add_rcu(&pwq->pwqs_node, &wq->pwqs);
spin_unlock_irq(&workqueue_lock);
