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-rw-r--r--kernel/workqueue.c32
1 files changed, 22 insertions, 10 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f02c4a4a0c3c..55f5f0afcd0d 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);
@@ -4756,7 +4761,14 @@ 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);
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