make sure that kernel_thread() callbacks call do_exit() themselves

[~andy/linux] / kernel / workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 1e1373bcb3e3125f72baf77cf396689d18de9bdd..3c5a79e2134cac6f404673093a84df5c8b371d80 100644 (file)
--- 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);