is_chained_work() is too complicated. we can simply found out
whether current task is worker by PF_WQ_WORKER or wq->rescuer.
Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
kernel/workqueue.c | 36 ++++++++++++------------------------
1 files changed, 12 insertions(+), 24 deletions(-)
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index e41c562..c718b94 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1182,34 +1182,22 @@ static void insert_work(struct cpu_workqueue_struct
*cwq,
/*
* Test whether @work is being queued from another work executing on the
- * same workqueue. This is rather expensive and should only be used from
- * cold paths.
+ * same workqueue.
*/
static bool is_chained_work(struct workqueue_struct *wq)
{
- unsigned long flags;
- unsigned int cpu;
+ struct worker *worker = NULL;
- for_each_gcwq_cpu(cpu) {
- struct global_cwq *gcwq = get_gcwq(cpu);
- struct worker *worker;
- struct hlist_node *pos;
- int i;
+ if (wq->rescuer && current == wq->rescuer->task) /* rescuer_thread() */
+ worker = wq->rescuer;
+ else if (current->flags & PF_WQ_WORKER) /* worker_thread() */
+ worker = kthread_data(current);
- spin_lock_irqsave(&gcwq->lock, flags);
- for_each_busy_worker(worker, i, pos, gcwq) {
- if (worker->task != current)
- continue;
- spin_unlock_irqrestore(&gcwq->lock, flags);
- /*
- * I'm @worker, no locking necessary. See if @work
- * is headed to the same workqueue.
- */
- return worker->current_cwq->wq == wq;
- }
- spin_unlock_irqrestore(&gcwq->lock, flags);
- }
- return false;
+ /*
+ * I'm @worker, no locking necessary. See if @work
+ * is headed to the same workqueue.
+ */
+ return worker && worker->current_cwq->wq == wq;
}
static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
@@ -1231,7 +1219,7 @@ static void __queue_work(unsigned int cpu, struct
workqueue_struct *wq,
debug_work_activate(work);
- /* if dying, only works from the same workqueue are allowed */
+ /* if draining, only works from the same workqueue are allowed */
if (unlikely(wq->flags & WQ_DRAINING) &&
WARN_ON_ONCE(!is_chained_work(wq)))
return;
--
1.7.7.6
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