1 files changed, 19 insertions, 4 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 2c2f971f3e75..23231237f2e2 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3647,8 +3647,12 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
                 return -EINVAL;
 
         /* creating multiple pwqs breaks ordering guarantee */
-        if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))
-                return -EINVAL;
+        if (!list_empty(&wq->pwqs)) {
+                if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
+                        return -EINVAL;
+
+                wq->flags &= ~__WQ_ORDERED;
+        }
 
         ctx = apply_wqattrs_prepare(wq, attrs);
 
@@ -3834,6 +3838,16 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
         struct workqueue_struct *wq;
         struct pool_workqueue *pwq;
 
+        /*
+         * Unbound && max_active == 1 used to imply ordered, which is no
+         * longer the case on NUMA machines due to per-node pools.  While
+         * alloc_ordered_workqueue() is the right way to create an ordered
+         * workqueue, keep the previous behavior to avoid subtle breakages
+         * on NUMA.
+         */
+        if ((flags & WQ_UNBOUND) && max_active == 1)
+                flags |= __WQ_ORDERED;
+
         /* see the comment above the definition of WQ_POWER_EFFICIENT */
         if ((flags & WQ_POWER_EFFICIENT) && wq_power_efficient)
                 flags |= WQ_UNBOUND;
@@ -4022,13 +4036,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
         struct pool_workqueue *pwq;
 
         /* disallow meddling with max_active for ordered workqueues */
-        if (WARN_ON(wq->flags & __WQ_ORDERED))
+        if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
                 return;
 
         max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
 
         mutex_lock(&wq->mutex);
 
+        wq->flags &= ~__WQ_ORDERED;
         wq->saved_max_active = max_active;
 
         for_each_pwq(pwq, wq)
@@ -5154,7 +5169,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq)
          * attributes breaks ordering guarantee.  Disallow exposing ordered
          * workqueues.
          */
-        if (WARN_ON(wq->flags & __WQ_ORDERED))
+        if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
                 return -EINVAL;
 
         wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);