1 files changed, 34 insertions, 10 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0b72e816b8d0..7f5d4be22034 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2817,6 +2817,19 @@ already_gone:
         return false;
 }
 
+static bool __flush_work(struct work_struct *work)
+{
+        struct wq_barrier barr;
+
+        if (start_flush_work(work, &barr)) {
+                wait_for_completion(&barr.done);
+                destroy_work_on_stack(&barr.work);
+                return true;
+        } else {
+                return false;
+        }
+}
+
 /**
  * flush_work - wait for a work to finish executing the last queueing instance
  * @work: the work to flush
@@ -2830,18 +2843,10 @@ already_gone:
  */
 bool flush_work(struct work_struct *work)
 {
-        struct wq_barrier barr;
-
         lock_map_acquire(&work->lockdep_map);
         lock_map_release(&work->lockdep_map);
 
-        if (start_flush_work(work, &barr)) {
-                wait_for_completion(&barr.done);
-                destroy_work_on_stack(&barr.work);
-                return true;
-        } else {
-                return false;
-        }
+        return __flush_work(work);
 }
 EXPORT_SYMBOL_GPL(flush_work);
 
@@ -3411,6 +3416,12 @@ static void copy_workqueue_attrs(struct workqueue_attrs *to,
 {
         to->nice = from->nice;
         cpumask_copy(to->cpumask, from->cpumask);
+        /*
+         * Unlike hash and equality test, this function doesn't ignore
+         * ->no_numa as it is used for both pool and wq attrs.  Instead,
+         * get_unbound_pool() explicitly clears ->no_numa after copying.
+         */
+        to->no_numa = from->no_numa;
 }
 
 /* hash value of the content of @attr */
@@ -3578,6 +3589,12 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
         lockdep_set_subclass(&pool->lock, 1);   /* see put_pwq() */
         copy_workqueue_attrs(pool->attrs, attrs);
 
+        /*
+         * no_numa isn't a worker_pool attribute, always clear it.  See
+         * 'struct workqueue_attrs' comments for detail.
+         */
+        pool->attrs->no_numa = false;
+
         /* if cpumask is contained inside a NUMA node, we belong to that node */
         if (wq_numa_enabled) {
                 for_each_node(node) {
@@ -4756,7 +4773,14 @@ long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
 
         INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn);
         schedule_work_on(cpu, &wfc.work);
-        flush_work(&wfc.work);
+
+        /*
+         * The work item is on-stack and can't lead to deadlock through
+         * flushing.  Use __flush_work() to avoid spurious lockdep warnings
+         * when work_on_cpu()s are nested.
+         */
+        __flush_work(&wfc.work);
+
         return wfc.ret;
 }
 EXPORT_SYMBOL_GPL(work_on_cpu);