6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Tejun Heo <tj@xxxxxxxxxx>
commit aac8a59537dfc704ff344f1aacfd143c089ee20f upstream.
This reverts commit ca10d851b9ad0338c19e8e3089e24d565ebfffd7.
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 3bc1e711c26b ("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@xxxxxxxxxx>
Fixes: 3bc1e711c26b ("workqueue: Don't implicitly make UNBOUND workqueues w/ @max_active==1 ordered")
Fixes: ca10d851b9ad ("workqueue: Override implicit ordered attribute in workqueue_apply_unbound_cpumask()")
Cc: stable@xxxxxxxxxxxxxxx # v6.6+
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/workqueue.c | 8 ++------
1 file changed, 2 insertions(+), 6 deletions(-)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -5793,13 +5793,9 @@ static int workqueue_apply_unbound_cpuma
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)
- continue;
- wq->flags &= ~__WQ_ORDERED;
- }
+ if (wq->flags & __WQ_ORDERED)
+ continue;
ctx = apply_wqattrs_prepare(wq, wq->unbound_attrs, unbound_cpumask);
if (IS_ERR(ctx)) {
