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>

1 files changed, 33 insertions, 23 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 43d18cb46308..5baac7c8a5f9 100644
--- 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;