workqueue: ensure attrs changes are properly synchronized
Current modification to attrs via sysfs is not fully synchronized.
Process A (change cpumask) | Process B (change numa affinity)
wq_cpumask_store() |
wq_sysfs_prep_attrs() |
| apply_workqueue_attrs()
apply_workqueue_attrs() |
It results that the Process B's operation is totally reverted
without any notification, it is a buggy behavior. So this patch
moves wq_sysfs_prep_attrs() into the protection under wq_pool_mutex
to ensure attrs changes are properly synchronized.
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 72c1adb..8019075 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4954,18 +4954,22 @@
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
- int ret;
+ int ret = -ENOMEM;
+
+ apply_wqattrs_lock();
attrs = wq_sysfs_prep_attrs(wq);
if (!attrs)
- return -ENOMEM;
+ goto out_unlock;
if (sscanf(buf, "%d", &attrs->nice) == 1 &&
attrs->nice >= MIN_NICE && attrs->nice <= MAX_NICE)
- ret = apply_workqueue_attrs(wq, attrs);
+ ret = apply_workqueue_attrs_locked(wq, attrs);
else
ret = -EINVAL;
+out_unlock:
+ apply_wqattrs_unlock();
free_workqueue_attrs(attrs);
return ret ?: count;
}
@@ -4989,16 +4993,20 @@
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
- int ret;
+ int ret = -ENOMEM;
+
+ apply_wqattrs_lock();
attrs = wq_sysfs_prep_attrs(wq);
if (!attrs)
- return -ENOMEM;
+ goto out_unlock;
ret = cpumask_parse(buf, attrs->cpumask);
if (!ret)
- ret = apply_workqueue_attrs(wq, attrs);
+ ret = apply_workqueue_attrs_locked(wq, attrs);
+out_unlock:
+ apply_wqattrs_unlock();
free_workqueue_attrs(attrs);
return ret ?: count;
}
@@ -5022,18 +5030,22 @@
{
struct workqueue_struct *wq = dev_to_wq(dev);
struct workqueue_attrs *attrs;
- int v, ret;
+ int v, ret = -ENOMEM;
+
+ apply_wqattrs_lock();
attrs = wq_sysfs_prep_attrs(wq);
if (!attrs)
- return -ENOMEM;
+ goto out_unlock;
ret = -EINVAL;
if (sscanf(buf, "%d", &v) == 1) {
attrs->no_numa = !v;
- ret = apply_workqueue_attrs(wq, attrs);
+ ret = apply_workqueue_attrs_locked(wq, attrs);
}
+out_unlock:
+ apply_wqattrs_unlock();
free_workqueue_attrs(attrs);
return ret ?: count;
}