Commit a799f35e authored by Tejun Heo's avatar Tejun Heo Committed by Greg Kroah-Hartman

workqueue: implicit ordered attribute should be overridable

commit 0a94efb5 upstream.

5c0338c6 ("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.
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Fixes: 5c0338c6 ("workqueue: restore WQ_UNBOUND/max_active==1 to be ordered")
Cc: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 644b39ef
...@@ -323,6 +323,7 @@ enum { ...@@ -323,6 +323,7 @@ enum {
__WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */ __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */
__WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */ __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */
__WQ_ORDERED_EXPLICIT = 1 << 18, /* internal: alloc_ordered_workqueue() */
__WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */ __WQ_LEGACY = 1 << 18, /* internal: create*_workqueue() */
WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */ WQ_MAX_ACTIVE = 512, /* I like 512, better ideas? */
...@@ -422,7 +423,8 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, ...@@ -422,7 +423,8 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active,
* Pointer to the allocated workqueue on success, %NULL on failure. * Pointer to the allocated workqueue on success, %NULL on failure.
*/ */
#define alloc_ordered_workqueue(fmt, flags, args...) \ #define alloc_ordered_workqueue(fmt, flags, args...) \
alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args) alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | \
__WQ_ORDERED_EXPLICIT | (flags), 1, ##args)
#define create_workqueue(name) \ #define create_workqueue(name) \
alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name)) alloc_workqueue("%s", __WQ_LEGACY | WQ_MEM_RECLAIM, 1, (name))
......
...@@ -3744,9 +3744,13 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq, ...@@ -3744,9 +3744,13 @@ static int apply_workqueue_attrs_locked(struct workqueue_struct *wq,
return -EINVAL; return -EINVAL;
/* creating multiple pwqs breaks ordering guarantee */ /* creating multiple pwqs breaks ordering guarantee */
if (WARN_ON((wq->flags & __WQ_ORDERED) && !list_empty(&wq->pwqs))) if (!list_empty(&wq->pwqs)) {
if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
return -EINVAL; return -EINVAL;
wq->flags &= ~__WQ_ORDERED;
}
ctx = apply_wqattrs_prepare(wq, attrs); ctx = apply_wqattrs_prepare(wq, attrs);
if (!ctx) if (!ctx)
return -ENOMEM; return -ENOMEM;
...@@ -4129,13 +4133,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active) ...@@ -4129,13 +4133,14 @@ void workqueue_set_max_active(struct workqueue_struct *wq, int max_active)
struct pool_workqueue *pwq; struct pool_workqueue *pwq;
/* disallow meddling with max_active for ordered workqueues */ /* disallow meddling with max_active for ordered workqueues */
if (WARN_ON(wq->flags & __WQ_ORDERED)) if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
return; return;
max_active = wq_clamp_max_active(max_active, wq->flags, wq->name); max_active = wq_clamp_max_active(max_active, wq->flags, wq->name);
mutex_lock(&wq->mutex); mutex_lock(&wq->mutex);
wq->flags &= ~__WQ_ORDERED;
wq->saved_max_active = max_active; wq->saved_max_active = max_active;
for_each_pwq(pwq, wq) for_each_pwq(pwq, wq)
...@@ -5263,7 +5268,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq) ...@@ -5263,7 +5268,7 @@ int workqueue_sysfs_register(struct workqueue_struct *wq)
* attributes breaks ordering guarantee. Disallow exposing ordered * attributes breaks ordering guarantee. Disallow exposing ordered
* workqueues. * workqueues.
*/ */
if (WARN_ON(wq->flags & __WQ_ORDERED)) if (WARN_ON(wq->flags & __WQ_ORDERED_EXPLICIT))
return -EINVAL; return -EINVAL;
wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL); wq->wq_dev = wq_dev = kzalloc(sizeof(*wq_dev), GFP_KERNEL);
......
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