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-rw-r--r--kernel/workqueue.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 590f4d04..cecd4ff 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3494,9 +3494,14 @@ int apply_workqueue_attrs(struct workqueue_struct *wq,
struct pool_workqueue *pwq, *last_pwq;
struct worker_pool *pool;
+ /* only unbound workqueues can change attributes */
if (WARN_ON(!(wq->flags & WQ_UNBOUND)))
return -EINVAL;
+ /* creating multiple pwqs breaks ordering guarantee */
+ if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))
+ return -EINVAL;
+
pwq = kmem_cache_zalloc(pwq_cache, GFP_KERNEL);
if (!pwq)
return -ENOMEM;
@@ -3752,6 +3757,10 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
{
struct pool_workqueue *pwq;
+ /* disallow meddling with max_active for ordered workqueues */
+ if (WARN_ON(wq->flags & __WQ_ORDERED))
+ return;
+
max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
spin_lock_irq(&workqueue_lock);
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