workqueue: allow WQ_MEM_RECLAIM on early init workqueues

Workqueues can be created early during boot before workqueue subsystem
in fully online - work items are queued waiting for later full
initialization.  However, early init wasn't supported for
WQ_MEM_RECLAIM workqueues causing unnecessary annoyances for a subset
of users.  Expand early init support to include WQ_MEM_RECLAIM
workqueues.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 5baac7c8a5f9..c86cc1ed678b 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4032,7 +4032,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
         if (alloc_and_link_pwqs(wq) < 0)
                 goto err_free_wq;
 
-        if (init_rescuer(wq) < 0)
+        if (wq_online && init_rescuer(wq) < 0)
                 goto err_destroy;
 
         if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
@@ -5639,6 +5639,8 @@ int __init workqueue_init(void)
          * archs such as power and arm64.  As per-cpu pools created
          * previously could be missing node hint and unbound pools NUMA
          * affinity, fix them up.
+         *
+         * Also, while iterating workqueues, create rescuers if requested.
          */
         wq_numa_init();
 
@@ -5650,8 +5652,12 @@ int __init workqueue_init(void)
                 }
         }
 
-        list_for_each_entry(wq, &workqueues, list)
+        list_for_each_entry(wq, &workqueues, list) {
                 wq_update_unbound_numa(wq, smp_processor_id(), true);
+                WARN(init_rescuer(wq),
+                     "workqueue: failed to create early rescuer for %s",
+                     wq->name);
+        }
 
         mutex_unlock(&wq_pool_mutex);