workqueue: separate out init_rescuer()

Separate out init_rescuer() from __alloc_workqueue_key() to prepare
for early init support for WQ_MEM_RECLAIM.  This patch doesn't
introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 43d18cb..5baac7c 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3939,6 +3939,37 @@ static int wq_clamp_max_active(int max_active, unsigned int flags,
        return clamp_val(max_active, 1, lim);
 }
 
+/*
+ * Workqueues which may be used during memory reclaim should have a rescuer
+ * to guarantee forward progress.
+ */
+static int init_rescuer(struct workqueue_struct *wq)
+{
+       struct worker *rescuer;
+       int ret;
+
+       if (!(wq->flags & WQ_MEM_RECLAIM))
+               return 0;
+
+       rescuer = alloc_worker(NUMA_NO_NODE);
+       if (!rescuer)
+               return -ENOMEM;
+
+       rescuer->rescue_wq = wq;
+       rescuer->task = kthread_create(rescuer_thread, rescuer, "%s", wq->name);
+       ret = PTR_ERR_OR_ZERO(rescuer->task);
+       if (ret) {
+               kfree(rescuer);
+               return ret;
+       }
+
+       wq->rescuer = rescuer;
+       kthread_bind_mask(rescuer->task, cpu_possible_mask);
+       wake_up_process(rescuer->task);
+
+       return 0;
+}
+
 struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
                                               unsigned int flags,
                                               int max_active,
@@ -4001,29 +4032,8 @@ struct workqueue_struct *__alloc_workqueue_key(const char *fmt,
        if (alloc_and_link_pwqs(wq) < 0)
                goto err_free_wq;
 
-       /*
-        * Workqueues which may be used during memory reclaim should
-        * have a rescuer to guarantee forward progress.
-        */
-       if (flags & WQ_MEM_RECLAIM) {
-               struct worker *rescuer;
-
-               rescuer = alloc_worker(NUMA_NO_NODE);
-               if (!rescuer)
-                       goto err_destroy;
-
-               rescuer->rescue_wq = wq;
-               rescuer->task = kthread_create(rescuer_thread, rescuer, "%s",
-                                              wq->name);
-               if (IS_ERR(rescuer->task)) {
-                       kfree(rescuer);
-                       goto err_destroy;
-               }
-
-               wq->rescuer = rescuer;
-               kthread_bind_mask(rescuer->task, cpu_possible_mask);
-               wake_up_process(rescuer->task);
-       }
+       if (init_rescuer(wq) < 0)
+               goto err_destroy;
 
        if ((wq->flags & WQ_SYSFS) && workqueue_sysfs_register(wq))
                goto err_destroy;