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| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2015-05-19 12:03:48 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2015-05-19 23:37:00 +0200 |
| commit | d4d3e2579756e3a5f4fbf8eac211f0696e253bcd (patch) | |
| tree | b6d880e578cd07db0d60a8dee86c28d67abb446c | |
| parent | workqueue: separate out and refactor the locking of applying attrs (diff) | |
| download | linux-d4d3e2579756e3a5f4fbf8eac211f0696e253bcd.tar.xz linux-d4d3e2579756e3a5f4fbf8eac211f0696e253bcd.zip | |
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>
| -rw-r--r-- | kernel/workqueue.c | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 72c1adbf7632..80190755a3c4 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -4954,18 +4954,22 @@ static ssize_t wq_nice_store(struct device *dev, struct device_attribute *attr, { 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 @@ static ssize_t wq_cpumask_store(struct device *dev, { 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 @@ static ssize_t wq_numa_store(struct device *dev, struct device_attribute *attr, { 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; } |