workqueue: clear leftover flags when detached

When a worker is detached, the worker->flags may still have WORKER_UNBOUND
or WORKER_REBOUND, it is OK for all cases:
  1) if it is a normal worker, the worker will be dead, it is OK.
  2) if it is a rescuer, it may re-attach to a pool with this leftover flag[s],
     it is still correct except it may cause unneeded wakeup.

It is correct but not good, so we just remove the leftover flags.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 4cfcd027e4bfd9b6c2c0dca5c5431f3fa40bf240..4f8d72dae0e8786223a2d275f3c73cf6b0585e3b 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1663,6 +1663,9 @@ static void worker_detach_from_pool(struct worker *worker,
                detach_completion = pool->detach_completion;
        mutex_unlock(&pool->attach_mutex);
 
+       /* clear leftover flags without pool->lock after it is detached */
+       worker->flags &= ~(WORKER_UNBOUND | WORKER_REBOUND);
+
        if (detach_completion)
                complete(detach_completion);
 }