workqueue: separate out process_one_work()

Separate out process_one_work() out of run_workqueue().  This patch
doesn't cause any behavior change.

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

1 files changed, 61 insertions, 39 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 5c49d762293b..8e3082b76c7f 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -402,51 +402,73 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
 }
 EXPORT_SYMBOL_GPL(queue_delayed_work_on);
 
+/**
+ * process_one_work - process single work
+ * @cwq: cwq to process work for
+ * @work: work to process
+ *
+ * Process @work.  This function contains all the logics necessary to
+ * process a single work including synchronization against and
+ * interaction with other workers on the same cpu, queueing and
+ * flushing.  As long as context requirement is met, any worker can
+ * call this function to process a work.
+ *
+ * CONTEXT:
+ * spin_lock_irq(cwq->lock) which is released and regrabbed.
+ */
+static void process_one_work(struct cpu_workqueue_struct *cwq,
+                             struct work_struct *work)
+{
+        work_func_t f = work->func;
+#ifdef CONFIG_LOCKDEP
+        /*
+         * It is permissible to free the struct work_struct from
+         * inside the function that is called from it, this we need to
+         * take into account for lockdep too.  To avoid bogus "held
+         * lock freed" warnings as well as problems when looking into
+         * work->lockdep_map, make a copy and use that here.
+         */
+        struct lockdep_map lockdep_map = work->lockdep_map;
+#endif
+        /* claim and process */
+        trace_workqueue_execution(cwq->thread, work);
+        debug_work_deactivate(work);
+        cwq->current_work = work;
+        list_del_init(&work->entry);
+
+        spin_unlock_irq(&cwq->lock);
+
+        BUG_ON(get_wq_data(work) != cwq);
+        work_clear_pending(work);
+        lock_map_acquire(&cwq->wq->lockdep_map);
+        lock_map_acquire(&lockdep_map);
+        f(work);
+        lock_map_release(&lockdep_map);
+        lock_map_release(&cwq->wq->lockdep_map);
+
+        if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
+                printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
+                       "%s/0x%08x/%d\n",
+                       current->comm, preempt_count(), task_pid_nr(current));
+                printk(KERN_ERR "    last function: ");
+                print_symbol("%s\n", (unsigned long)f);
+                debug_show_held_locks(current);
+                dump_stack();
+        }
+
+        spin_lock_irq(&cwq->lock);
+
+        /* we're done with it, release */
+        cwq->current_work = NULL;
+}
+
 static void run_workqueue(struct cpu_workqueue_struct *cwq)
 {
         spin_lock_irq(&cwq->lock);
         while (!list_empty(&cwq->worklist)) {
                 struct work_struct *work = list_entry(cwq->worklist.next,
                                                 struct work_struct, entry);
-                work_func_t f = work->func;
-#ifdef CONFIG_LOCKDEP
-                /*
-                 * It is permissible to free the struct work_struct
-                 * from inside the function that is called from it,
-                 * this we need to take into account for lockdep too.
-                 * To avoid bogus "held lock freed" warnings as well
-                 * as problems when looking into work->lockdep_map,
-                 * make a copy and use that here.
-                 */
-                struct lockdep_map lockdep_map = work->lockdep_map;
-#endif
-                trace_workqueue_execution(cwq->thread, work);
-                debug_work_deactivate(work);
-                cwq->current_work = work;
-                list_del_init(cwq->worklist.next);
-                spin_unlock_irq(&cwq->lock);
-
-                BUG_ON(get_wq_data(work) != cwq);
-                work_clear_pending(work);
-                lock_map_acquire(&cwq->wq->lockdep_map);
-                lock_map_acquire(&lockdep_map);
-                f(work);
-                lock_map_release(&lockdep_map);
-                lock_map_release(&cwq->wq->lockdep_map);
-
-                if (unlikely(in_atomic() || lockdep_depth(current) > 0)) {
-                        printk(KERN_ERR "BUG: workqueue leaked lock or atomic: "
-                                        "%s/0x%08x/%d\n",
-                                        current->comm, preempt_count(),
-                                        task_pid_nr(current));
-                        printk(KERN_ERR "    last function: ");
-                        print_symbol("%s\n", (unsigned long)f);
-                        debug_show_held_locks(current);
-                        dump_stack();
-                }
-
-                spin_lock_irq(&cwq->lock);
-                cwq->current_work = NULL;
+                process_one_work(cwq, work);
         }
         spin_unlock_irq(&cwq->lock);
 }