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authorLai Jiangshan <laijs@cn.fujitsu.com>2015-05-12 20:32:30 +0800
committerTejun Heo <tj@kernel.org>2015-05-18 16:22:57 -0400
commitf7142ed483f49f9108bea1be0c1afcd5d9098e05 (patch)
treefd817533489b688026cbc94d4a0ec2cbec03b85b /kernel/workqueue.c
parent5b95e1af8d17d85a17728f6de7dbff538e6e3c49 (diff)
downloadlinux-sh-f7142ed483f49f9108bea1be0c1afcd5d9098e05.tar.gz
workqueue: simplify wq_update_unbound_numa()
wq_update_unbound_numa() is known be called with wq_pool_mutex held. But wq_update_unbound_numa() requests wq->mutex before reading wq->unbound_attrs, wq->numa_pwq_tbl[] and wq->dfl_pwq. But these fields were changed to be allowed being read with wq_pool_mutex held. So we simply remove the mutex_lock(&wq->mutex). Without the dependence on the the mutex_lock(&wq->mutex), the test of wq->unbound_attrs->no_numa can also be moved upward. The old code need a long comment to describe the stableness of @wq->unbound_attrs which is also guaranteed by wq_pool_mutex now, so we don't need this such comment. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r--kernel/workqueue.c20
1 files changed, 5 insertions, 15 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index b1c222270e0e..4a9f65b54ee5 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3708,7 +3708,8 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
lockdep_assert_held(&wq_pool_mutex);
- if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND))
+ if (!wq_numa_enabled || !(wq->flags & WQ_UNBOUND) ||
+ wq->unbound_attrs->no_numa)
return;
/*
@@ -3719,10 +3720,6 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
target_attrs = wq_update_unbound_numa_attrs_buf;
cpumask = target_attrs->cpumask;
- mutex_lock(&wq->mutex);
- if (wq->unbound_attrs->no_numa)
- goto out_unlock;
-
copy_workqueue_attrs(target_attrs, wq->unbound_attrs);
pwq = unbound_pwq_by_node(wq, node);
@@ -3734,33 +3731,26 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
*/
if (wq_calc_node_cpumask(wq->dfl_pwq->pool->attrs, node, cpu_off, cpumask)) {
if (cpumask_equal(cpumask, pwq->pool->attrs->cpumask))
- goto out_unlock;
+ return;
} else {
goto use_dfl_pwq;
}
- mutex_unlock(&wq->mutex);
-
/* create a new pwq */
pwq = alloc_unbound_pwq(wq, target_attrs);
if (!pwq) {
pr_warn("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n",
wq->name);
- mutex_lock(&wq->mutex);
goto use_dfl_pwq;
}
- /*
- * Install the new pwq. As this function is called only from CPU
- * hotplug callbacks and applying a new attrs is wrapped with
- * get/put_online_cpus(), @wq->unbound_attrs couldn't have changed
- * inbetween.
- */
+ /* Install the new pwq. */
mutex_lock(&wq->mutex);
old_pwq = numa_pwq_tbl_install(wq, node, pwq);
goto out_unlock;
use_dfl_pwq:
+ mutex_lock(&wq->mutex);
spin_lock_irq(&wq->dfl_pwq->pool->lock);
get_pwq(wq->dfl_pwq);
spin_unlock_irq(&wq->dfl_pwq->pool->lock);