The code of attaching is unfolded in create_worker().
Separating this code out will make the codes more clear.

Signed-off-by: Lai Jiangshan <la...@cn.fujitsu.com>
---
 kernel/workqueue.c |   55 +++++++++++++++++++++++++++++++++------------------
 1 files changed, 35 insertions(+), 20 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 728b515..4d021e0 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -66,7 +66,7 @@ enum {
         *
         * Note that DISASSOCIATED should be flipped only while holding
         * attach_mutex to avoid changing binding state while
-        * create_worker() is in progress.
+        * worker_attach_to_pool() is in progress.
         */
        POOL_DISASSOCIATED      = 1 << 2,       /* cpu can't serve workers */
        POOL_FREEZING           = 1 << 3,       /* freeze in progress */
@@ -1683,6 +1683,39 @@ static struct worker *alloc_worker(void)
 }
 
 /**
+ * worker_attach_to_pool() - attach the worker to the pool
+ * @worker: worker to be attached
+ * @pool: the target pool
+ *
+ * Attach the worker to the pool, thus the %WORKER_UNBOUND flag and
+ * cpu-binding of the worker are kept coordination with the pool
+ * across cpu-[un]hotplug.
+ */
+static void worker_attach_to_pool(struct worker *worker,
+                                  struct worker_pool *pool)
+{
+       mutex_lock(&pool->attach_mutex);
+
+       /*
+        * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
+        * online CPUs.  It'll be re-applied when any of the CPUs come up.
+        */
+       set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
+
+       /*
+        * The pool->attach_mutex ensures %POOL_DISASSOCIATED remains
+        * stable across this function.  See the comments above the
+        * flag definition for details.
+        */
+       if (pool->flags & POOL_DISASSOCIATED)
+               worker->flags |= WORKER_UNBOUND;
+
+       list_add_tail(&worker->node, &pool->workers);
+
+       mutex_unlock(&pool->attach_mutex);
+}
+
+/**
  * worker_detach_from_pool() - detach the worker from the pool
  * @worker: worker which is attached to its pool
  * @pool: attached pool
@@ -1753,26 +1786,8 @@ static struct worker *create_worker(struct worker_pool 
*pool)
        /* prevent userland from meddling with cpumask of workqueue workers */
        worker->task->flags |= PF_NO_SETAFFINITY;
 
-       mutex_lock(&pool->attach_mutex);
-
-       /*
-        * set_cpus_allowed_ptr() will fail if the cpumask doesn't have any
-        * online CPUs.  It'll be re-applied when any of the CPUs come up.
-        */
-       set_cpus_allowed_ptr(worker->task, pool->attrs->cpumask);
-
-       /*
-        * The pool->attach_mutex ensures %POOL_DISASSOCIATED
-        * remains stable across this function.  See the comments above the
-        * flag definition for details.
-        */
-       if (pool->flags & POOL_DISASSOCIATED)
-               worker->flags |= WORKER_UNBOUND;
-
        /* successful, attach the worker to the pool */
-       list_add_tail(&worker->node, &pool->workers);
-
-       mutex_unlock(&pool->attach_mutex);
+       worker_attach_to_pool(worker, pool);
 
        return worker;
 
-- 
1.7.4.4

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