CPU_UP_PREPARE binds cwq->thread to the new CPU. So CPU_UP_CANCELED tries to
wake up the task which is bound to the failed CPU.
With this patch we don't bind cwq->thread until CPU becomes online. The first
wake_up() after kthread_create() is a bit special, make a simple helper for
that.
Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
--- OLD/kernel/workqueue.c~2_BIND 2007-05-01 22:18:15.000000000 +0400
+++ OLD/kernel/workqueue.c 2007-05-02 00:17:01.000000000 +0400
@@ -631,15 +631,21 @@ static int create_workqueue_thread(struc
cwq->thread = p;
cwq->should_stop = 0;
- if (!is_single_threaded(wq))
- kthread_bind(p, cpu);
-
- if (is_single_threaded(wq) || cpu_online(cpu))
- wake_up_process(p);
return 0;
}
+static void start_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
+{
+ struct task_struct *p = cwq->thread;
+
+ if (p != NULL) {
+ if (cpu >= 0)
+ kthread_bind(p, cpu);
+ wake_up_process(p);
+ }
+}
+
struct workqueue_struct *__create_workqueue(const char *name,
int singlethread, int freezeable)
{
@@ -665,6 +671,7 @@ struct workqueue_struct *__create_workqu
if (singlethread) {
cwq = init_cpu_workqueue(wq, singlethread_cpu);
err = create_workqueue_thread(cwq, singlethread_cpu);
+ start_workqueue_thread(cwq, -1);
} else {
mutex_lock(&workqueue_mutex);
list_add(&wq->list, &workqueues);
@@ -674,6 +681,7 @@ struct workqueue_struct *__create_workqu
if (err || !cpu_online(cpu))
continue;
err = create_workqueue_thread(cwq, cpu);
+ start_workqueue_thread(cwq, cpu);
}
mutex_unlock(&workqueue_mutex);
}
@@ -773,12 +781,11 @@ static int __devinit workqueue_cpu_callb
return NOTIFY_BAD;
case CPU_ONLINE:
- wake_up_process(cwq->thread);
+ start_workqueue_thread(cwq, cpu);
break;
case CPU_UP_CANCELED:
- if (cwq->thread)
- wake_up_process(cwq->thread);
+ start_workqueue_thread(cwq, -1);
case CPU_DEAD:
cleanup_workqueue_thread(cwq, cpu);
break;
-
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