1 files changed, 18 insertions, 19 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 1e1373bcb3e3..3c5a79e2134c 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1349,8 +1349,16 @@ static void busy_worker_rebind_fn(struct work_struct *work)
         struct worker *worker = container_of(work, struct worker, rebind_work);
         struct global_cwq *gcwq = worker->pool->gcwq;
 
-        if (worker_maybe_bind_and_lock(worker))
-                worker_clr_flags(worker, WORKER_REBIND);
+        worker_maybe_bind_and_lock(worker);
+
+        /*
+         * %WORKER_REBIND must be cleared even if the above binding failed;
+         * otherwise, we may confuse the next CPU_UP cycle or oops / get
+         * stuck by calling idle_worker_rebind() prematurely.  If CPU went
+         * down again inbetween, %WORKER_UNBOUND would be set, so clearing
+         * %WORKER_REBIND is always safe.
+         */
+        worker_clr_flags(worker, WORKER_REBIND);
 
         spin_unlock_irq(&gcwq->lock);
 }
@@ -3568,18 +3576,17 @@ static int __devinit workqueue_cpu_down_callback(struct notifier_block *nfb,
 #ifdef CONFIG_SMP
 
 struct work_for_cpu {
-        struct completion completion;
+        struct work_struct work;
         long (*fn)(void *);
         void *arg;
         long ret;
 };
 
-static int do_work_for_cpu(void *_wfc)
+static void work_for_cpu_fn(struct work_struct *work)
 {
-        struct work_for_cpu *wfc = _wfc;
+        struct work_for_cpu *wfc = container_of(work, struct work_for_cpu, work);
+
         wfc->ret = wfc->fn(wfc->arg);
-        complete(&wfc->completion);
-        return 0;
 }
 
 /**
@@ -3594,19 +3601,11 @@ static int do_work_for_cpu(void *_wfc)
  */
 long work_on_cpu(unsigned int cpu, long (*fn)(void *), void *arg)
 {
-        struct task_struct *sub_thread;
-        struct work_for_cpu wfc = {
-                .completion = COMPLETION_INITIALIZER_ONSTACK(wfc.completion),
-                .fn = fn,
-                .arg = arg,
-        };
+        struct work_for_cpu wfc = { .fn = fn, .arg = arg };
 
-        sub_thread = kthread_create(do_work_for_cpu, &wfc, "work_for_cpu");
-        if (IS_ERR(sub_thread))
-                return PTR_ERR(sub_thread);
-        kthread_bind(sub_thread, cpu);
-        wake_up_process(sub_thread);
-        wait_for_completion(&wfc.completion);
+        INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn);
+        schedule_work_on(cpu, &wfc.work);
+        flush_work(&wfc.work);
         return wfc.ret;
 }
 EXPORT_SYMBOL_GPL(work_on_cpu);