workqueue: factor out initial worker creation into create_and_start_worker()

get_unbound_pool(), workqueue_cpu_up_callback() and init_workqueues()
have similar code pieces to create and start the initial worker factor
those out into create_and_start_worker().

This patch doesn't introduce any functional changes.

Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index bc25bdf..cac7106 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1793,6 +1793,26 @@ static void start_worker(struct worker *worker)
 }
 
 /**
+ * create_and_start_worker - create and start a worker for a pool
+ * @pool: the target pool
+ *
+ * Create and start a new worker for @pool.
+ */
+static int create_and_start_worker(struct worker_pool *pool)
+{
+       struct worker *worker;
+
+       worker = create_worker(pool);
+       if (worker) {
+               spin_lock_irq(&pool->lock);
+               start_worker(worker);
+               spin_unlock_irq(&pool->lock);
+       }
+
+       return worker ? 0 : -ENOMEM;
+}
+
+/**
  * destroy_worker - destroy a workqueue worker
  * @worker: worker to be destroyed
  *
@@ -3542,7 +3562,6 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
        static DEFINE_MUTEX(create_mutex);
        u32 hash = wqattrs_hash(attrs);
        struct worker_pool *pool;
-       struct worker *worker;
 
        mutex_lock(&create_mutex);
 
@@ -3568,14 +3587,9 @@ static struct worker_pool *get_unbound_pool(const struct workqueue_attrs *attrs)
                goto fail;
 
        /* create and start the initial worker */
-       worker = create_worker(pool);
-       if (!worker)
+       if (create_and_start_worker(pool) < 0)
                goto fail;
 
-       spin_lock_irq(&pool->lock);
-       start_worker(worker);
-       spin_unlock_irq(&pool->lock);
-
        /* install */
        spin_lock_irq(&workqueue_lock);
        hash_add(unbound_pool_hash, &pool->hash_node, hash);
@@ -4148,18 +4162,10 @@ static int __cpuinit workqueue_cpu_up_callback(struct notifier_block *nfb,
        switch (action & ~CPU_TASKS_FROZEN) {
        case CPU_UP_PREPARE:
                for_each_cpu_worker_pool(pool, cpu) {
-                       struct worker *worker;
-
                        if (pool->nr_workers)
                                continue;
-
-                       worker = create_worker(pool);
-                       if (!worker)
+                       if (create_and_start_worker(pool) < 0)
                                return NOTIFY_BAD;
-
-                       spin_lock_irq(&pool->lock);
-                       start_worker(worker);
-                       spin_unlock_irq(&pool->lock);
                }
                break;
 
@@ -4409,15 +4415,8 @@ static int __init init_workqueues(void)
                struct worker_pool *pool;
 
                for_each_cpu_worker_pool(pool, cpu) {
-                       struct worker *worker;
-
                        pool->flags &= ~POOL_DISASSOCIATED;
-
-                       worker = create_worker(pool);
-                       BUG_ON(!worker);
-                       spin_lock_irq(&pool->lock);
-                       start_worker(worker);
-                       spin_unlock_irq(&pool->lock);
+                       BUG_ON(create_and_start_worker(pool) < 0);
                }
        }