Commit aac8a595 authored Feb 05, 2024 by Tejun Heo

Revert "workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()"



This reverts commit ca10d851.

The commit allowed workqueue_apply_unbound_cpumask() to clear __WQ_ORDERED
on now removed implicitly ordered workqueues. This was incorrect in that
system-wide config change shouldn't break ordering properties of all
workqueues. The reason why apply_workqueue_attrs() path was allowed to do so
was because it was targeting the specific workqueue - either the workqueue
had WQ_SYSFS set or the workqueue user specifically tried to change
max_active, both of which indicate that the workqueue doesn't need to be
ordered.

The implicitly ordered workqueue promotion was removed by the previous
commit 3bc1e711 ("workqueue: Don't implicitly make UNBOUND workqueues w/
@max_active==1 ordered"). However, it didn't update this path and broke
build. Let's revert the commit which was incorrect in the first place which
also fixes build.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 3bc1e711 ("workqueue: Don't implicitly make UNBOUND workqueues w/ @max_active==1 ordered")
Fixes: ca10d851 ("workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()")
Cc: stable@vger.kernel.org # v6.6+
Signed-off-by: Tejun Heo <tj@kernel.org>

parent 052d5343

kernel/workqueue.c

+2 −6

Original line number	Diff line number	Diff line
		@@ -5786,13 +5786,9 @@ static int workqueue_apply_unbound_cpumask(const cpumask_var_t unbound_cpumask)
		list_for_each_entry(wq, &workqueues, list) {
		if (!(wq->flags & WQ_UNBOUND))
		continue;

		/* creating multiple pwqs breaks ordering guarantee */
		if (!list_empty(&wq->pwqs)) {
		if (wq->flags & __WQ_ORDERED_EXPLICIT)
		if (wq->flags & __WQ_ORDERED)
		continue;
		wq->flags &= ~__WQ_ORDERED;
		}

		ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask);
		if (IS_ERR(ctx)) {