workqueue: use rcu_read_lock_sched() instead for accessing pwq in RCU
rcu_read_lock_sched() is better than preempt_disable() if the code is
protected by RCU_SCHED.
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 79d1d34..b6c5a52 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3962,7 +3962,7 @@
struct pool_workqueue *pwq;
bool ret;
- preempt_disable();
+ rcu_read_lock_sched();
if (!(wq->flags & WQ_UNBOUND))
pwq = per_cpu_ptr(wq->cpu_pwqs, cpu);
@@ -3970,7 +3970,7 @@
pwq = first_pwq(wq);
ret = !list_empty(&pwq->delayed_works);
- preempt_enable();
+ rcu_read_unlock_sched();
return ret;
}
@@ -4354,16 +4354,16 @@
* nr_active is monotonically decreasing. It's safe
* to peek without lock.
*/
- preempt_disable();
+ rcu_read_lock_sched();
for_each_pwq(pwq, wq) {
WARN_ON_ONCE(pwq->nr_active < 0);
if (pwq->nr_active) {
busy = true;
- preempt_enable();
+ rcu_read_unlock_sched();
goto out_unlock;
}
}
- preempt_enable();
+ rcu_read_unlock_sched();
}
out_unlock:
mutex_unlock(&wq_mutex);