diff --git a/kernel/workqueue.c b/kernel/workqueue.c index d80dbdceadb8..1d1933cf3778 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -64,6 +64,7 @@ struct workqueue_struct { /* All the per-cpu workqueues on the system, for hotplug cpu to add/remove threads to each one as cpus come/go. */ +static long migrate_sequence __read_mostly; static DEFINE_MUTEX(workqueue_mutex); static LIST_HEAD(workqueues); @@ -421,13 +422,7 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) * Probably keventd trying to flush its own queue. So simply run * it by hand rather than deadlocking. */ - preempt_enable(); - /* - * We can still touch *cwq here because we are keventd, and - * hot-unplug will be waiting us to exit. - */ run_workqueue(cwq); - preempt_disable(); } else { struct wq_barrier barr; int active = 0; @@ -439,11 +434,8 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) } spin_unlock_irq(&cwq->lock); - if (active) { - preempt_enable(); + if (active) wait_for_completion(&barr.done); - preempt_disable(); - } } } @@ -462,17 +454,21 @@ static void flush_cpu_workqueue(struct cpu_workqueue_struct *cwq) */ void fastcall flush_workqueue(struct workqueue_struct *wq) { - preempt_disable(); /* CPU hotplug */ if (is_single_threaded(wq)) { /* Always use first cpu's area. */ flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, singlethread_cpu)); } else { + long sequence; int cpu; +again: + sequence = migrate_sequence; - for_each_online_cpu(cpu) + for_each_possible_cpu(cpu) flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu)); + + if (unlikely(sequence != migrate_sequence)) + goto again; } - preempt_enable(); } EXPORT_SYMBOL_GPL(flush_workqueue); @@ -544,18 +540,22 @@ out: } EXPORT_SYMBOL_GPL(flush_work); +static void init_cpu_workqueue(struct workqueue_struct *wq, int cpu) +{ + struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); + + cwq->wq = wq; + spin_lock_init(&cwq->lock); + INIT_LIST_HEAD(&cwq->worklist); + init_waitqueue_head(&cwq->more_work); +} + static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq, int cpu) { struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu); struct task_struct *p; - spin_lock_init(&cwq->lock); - cwq->wq = wq; - cwq->thread = NULL; - INIT_LIST_HEAD(&cwq->worklist); - init_waitqueue_head(&cwq->more_work); - if (is_single_threaded(wq)) p = kthread_create(worker_thread, cwq, "%s", wq->name); else @@ -589,6 +589,7 @@ struct workqueue_struct *__create_workqueue(const char *name, mutex_lock(&workqueue_mutex); if (singlethread) { INIT_LIST_HEAD(&wq->list); + init_cpu_workqueue(wq, singlethread_cpu); p = create_workqueue_thread(wq, singlethread_cpu); if (!p) destroy = 1; @@ -596,7 +597,11 @@ struct workqueue_struct *__create_workqueue(const char *name, wake_up_process(p); } else { list_add(&wq->list, &workqueues); - for_each_online_cpu(cpu) { + for_each_possible_cpu(cpu) { + init_cpu_workqueue(wq, cpu); + if (!cpu_online(cpu)) + continue; + p = create_workqueue_thread(wq, cpu); if (p) { kthread_bind(p, cpu); @@ -831,6 +836,7 @@ static void take_over_work(struct workqueue_struct *wq, unsigned int cpu) spin_lock_irq(&cwq->lock); list_replace_init(&cwq->worklist, &list); + migrate_sequence++; while (!list_empty(&list)) { printk("Taking work for %s\n", wq->name);