workqueue: handle NUMA_NO_NODE for unbound pool_workqueue lookup

[karo-tx-linux.git] / kernel / workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index c579dbab2e36ab20dd94a5f753a480df17ae28ff..ad98ea9673232632a0dcf0e8e83bbbe91a56991e 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -568,6 +568,16 @@ static struct pool_workqueue *unbound_pwq_by_node(struct workqueue_struct *wq,
                                                  int node)
 {
        assert_rcu_or_wq_mutex_or_pool_mutex(wq);
+
+       /*
+        * XXX: @node can be NUMA_NO_NODE if CPU goes offline while a
+        * delayed item is pending.  The plan is to keep CPU -> NODE
+        * mapping valid and stable across CPU on/offlines.  Once that
+        * happens, this workaround can be removed.
+        */
+       if (unlikely(node == NUMA_NO_NODE))
+               return wq->dfl_pwq;
+
        return rcu_dereference_raw(wq->numa_pwq_tbl[node]);
 }