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workqueue: implicit ordered attribute should be overridable

5c0338c68706 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered") automatically enabled ordered attribute for unbound workqueues w/ max_active == 1. Because ordered workqueues reject max_active and some attribute changes, this implicit ordered mode broke cases where the user creates an unbound workqueue w/ max_active == 1 and later explicitly changes the related attributes. This patch distinguishes explicit and implicit ordered setting and overrides from attribute changes if implict.

Tejun Heo committed 9 years ago

Commit 0a94efb1 parent 5c0338c2 files · +12 −5Browse files

Showing the changes to kernel/workqueue.c (1 of 2 files). Show all

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kernel/workqueue.c+9−4
@@ -3744,8 +3744,12 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, · 3743 unmodified lines
3744 return -EINVAL;3744 return -EINVAL;
3745 3745
3746 /* creating multiple pwqs breaks ordering guarantee */3746 /* creating multiple pwqs breaks ordering guarantee */
3747 if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs)))3747 if (!list_empty(&wq->pwqs)) {
3748 return -EINVAL;3748 if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
3749 return -EINVAL;
3750
3751 wq->flags &= ~__WQ_ORDERED;
3752 }
3749 3753
3750 ctx = apply_wqattrs_prepare(wq, attrs);3754 ctx = apply_wqattrs_prepare(wq, attrs);
3751 if (!ctx)3755 if (!ctx)
@@ -4129,13 +4133,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) · 377 unmodified lines
4129 struct pool_workqueue *pwq;4133 struct pool_workqueue *pwq;
4130 4134
4131 /* disallow meddling with max_active for ordered workqueues */4135 /* disallow meddling with max_active for ordered workqueues */
4132 if (WARN_ON(wq->flags & __WQ_ORDERED))4136 if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
4133 return;4137 return;
4134 4138
4135 max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);4139 max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
4136 4140
4137 mutex_lock(&wq->mutex);4141 mutex_lock(&wq->mutex);
4138 4142
4143 wq->flags &= ~__WQ_ORDERED;
4139 wq->saved_max_active = max_active;4144 wq->saved_max_active = max_active;
4140 4145
4141 for_each_pwq(pwq, wq)4146 for_each_pwq(pwq, wq)
@@ -5263,7 +5268,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq) · 1121 unmodified lines
5263 * attributes breaks ordering guarantee. Disallow exposing ordered5268 * attributes breaks ordering guarantee. Disallow exposing ordered
5264 * workqueues.5269 * workqueues.
5265 */5270 */
5266 if (WARN_ON(wq->flags & __WQ_ORDERED))5271 if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
5267 return -EINVAL;5272 return -EINVAL;
5268 5273
5269 wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);5274 wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);