1 files changed, 114 insertions, 29 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index a6d3634..ec7e4f6 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -125,7 +125,7 @@ struct cpu_workqueue_struct *get_wq_data(struct work_struct *work)
 }
 
 static void insert_work(struct cpu_workqueue_struct *cwq,
-				struct work_struct *work, int tail)
+			struct work_struct *work, struct list_head *head)
 {
 	set_wq_data(work, cwq);
 	/*
@@ -133,21 +133,17 @@ static void insert_work(struct cpu_workqueue_struct *cwq,
 	 * result of list_add() below, see try_to_grab_pending().
 	 */
 	smp_wmb();
-	if (tail)
-		list_add_tail(&work->entry, &cwq->worklist);
-	else
-		list_add(&work->entry, &cwq->worklist);
+	list_add_tail(&work->entry, head);
 	wake_up(&cwq->more_work);
 }
 
-/* Preempt must be disabled. */
 static void __queue_work(struct cpu_workqueue_struct *cwq,
 			 struct work_struct *work)
 {
 	unsigned long flags;
 
 	spin_lock_irqsave(&cwq->lock, flags);
-	insert_work(cwq, work, 1);
+	insert_work(cwq, work, &cwq->worklist);
 	spin_unlock_irqrestore(&cwq->lock, flags);
 }
 
@@ -163,17 +159,39 @@ static void __queue_work(struct cpu_workqueue_struct *cwq,
  */
 int queue_work(struct workqueue_struct *wq, struct work_struct *work)
 {
+	int ret;
+
+	ret = queue_work_on(get_cpu(), wq, work);
+	put_cpu();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(queue_work);
+
+/**
+ * queue_work_on - queue work on specific cpu
+ * @cpu: CPU number to execute work on
+ * @wq: workqueue to use
+ * @work: work to queue
+ *
+ * Returns 0 if @work was already on a queue, non-zero otherwise.
+ *
+ * We queue the work to a specific CPU, the caller must ensure it
+ * can't go away.
+ */
+int
+queue_work_on(int cpu, struct workqueue_struct *wq, struct work_struct *work)
+{
 	int ret = 0;
 
 	if (!test_and_set_bit(WORK_STRUCT_PENDING, work_data_bits(work))) {
 		BUG_ON(!list_empty(&work->entry));
-		__queue_work(wq_per_cpu(wq, get_cpu()), work);
-		put_cpu();
+		__queue_work(wq_per_cpu(wq, cpu), work);
 		ret = 1;
 	}
 	return ret;
 }
-EXPORT_SYMBOL_GPL(queue_work);
+EXPORT_SYMBOL_GPL(queue_work_on);
 
 static void delayed_work_timer_fn(unsigned long __data)
 {
@@ -337,14 +355,14 @@ static void wq_barrier_func(struct work_struct *work)
 }
 
 static void insert_wq_barrier(struct cpu_workqueue_struct *cwq,
-					struct wq_barrier *barr, int tail)
+			struct wq_barrier *barr, struct list_head *head)
 {
 	INIT_WORK(&barr->work, wq_barrier_func);
 	__set_bit(WORK_STRUCT_PENDING, work_data_bits(&barr->work));
 
 	init_completion(&barr->done);
 
-	insert_work(cwq, &barr->work, tail);
+	insert_work(cwq, &barr->work, head);
 }
 
 static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
@@ -364,7 +382,7 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
 		active = 0;
 		spin_lock_irq(&cwq->lock);
 		if (!list_empty(&cwq->worklist) || cwq->current_work != NULL) {
-			insert_wq_barrier(cwq, &barr, 1);
+			insert_wq_barrier(cwq, &barr, &cwq->worklist);
 			active = 1;
 		}
 		spin_unlock_irq(&cwq->lock);
@@ -402,6 +420,57 @@ void flush_workqueue(struct workqueue_struct *wq)
 }
 EXPORT_SYMBOL_GPL(flush_workqueue);
 
+/**
+ * flush_work - block until a work_struct's callback has terminated
+ * @work: the work which is to be flushed
+ *
+ * Returns false if @work has already terminated.
+ *
+ * It is expected that, prior to calling flush_work(), the caller has
+ * arranged for the work to not be requeued, otherwise it doesn't make
+ * sense to use this function.
+ */
+int flush_work(struct work_struct *work)
+{
+	struct cpu_workqueue_struct *cwq;
+	struct list_head *prev;
+	struct wq_barrier barr;
+
+	might_sleep();
+	cwq = get_wq_data(work);
+	if (!cwq)
+		return 0;
+
+	lock_acquire(&cwq->wq->lockdep_map, 0, 0, 0, 2, _THIS_IP_);
+	lock_release(&cwq->wq->lockdep_map, 1, _THIS_IP_);
+
+	prev = NULL;
+	spin_lock_irq(&cwq->lock);
+	if (!list_empty(&work->entry)) {
+		/*
+		 * See the comment near try_to_grab_pending()->smp_rmb().
+		 * If it was re-queued under us we are not going to wait.
+		 */
+		smp_rmb();
+		if (unlikely(cwq != get_wq_data(work)))
+			goto out;
+		prev = &work->entry;
+	} else {
+		if (cwq->current_work != work)
+			goto out;
+		prev = &cwq->worklist;
+	}
+	insert_wq_barrier(cwq, &barr, prev->next);
+out:
+	spin_unlock_irq(&cwq->lock);
+	if (!prev)
+		return 0;
+
+	wait_for_completion(&barr.done);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(flush_work);
+
 /*
  * Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
  * so this work can't be re-armed in any way.
@@ -449,7 +518,7 @@ static void wait_on_cpu_work(struct cpu_workqueue_struct *cwq,
 
 	spin_lock_irq(&cwq->lock);
 	if (unlikely(cwq->current_work == work)) {
-		insert_wq_barrier(cwq, &barr, 0);
+		insert_wq_barrier(cwq, &barr, cwq->worklist.next);
 		running = 1;
 	}
 	spin_unlock_irq(&cwq->lock);
@@ -553,6 +622,19 @@ int schedule_work(struct work_struct *work)
 }
 EXPORT_SYMBOL(schedule_work);
 
+/*
+ * schedule_work_on - put work task on a specific cpu
+ * @cpu: cpu to put the work task on
+ * @work: job to be done
+ *
+ * This puts a job on a specific cpu
+ */
+int schedule_work_on(int cpu, struct work_struct *work)
+{
+	return queue_work_on(cpu, keventd_wq, work);
+}
+EXPORT_SYMBOL(schedule_work_on);
+
 /**
  * schedule_delayed_work - put work task in global workqueue after delay
  * @dwork: job to be done
@@ -607,10 +689,10 @@ int schedule_on_each_cpu(work_func_t func)
 		struct work_struct *work = per_cpu_ptr(works, cpu);
 
 		INIT_WORK(work, func);
-		set_bit(WORK_STRUCT_PENDING, work_data_bits(work));
-		__queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work);
+		schedule_work_on(cpu, work);
 	}
-	flush_workqueue(keventd_wq);
+	for_each_online_cpu(cpu)
+		flush_work(per_cpu_ptr(works, cpu));
 	put_online_cpus();
 	free_percpu(works);
 	return 0;
@@ -747,7 +829,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
 		err = create_workqueue_thread(cwq, singlethread_cpu);
 		start_workqueue_thread(cwq, -1);
 	} else {
-		get_online_cpus();
+		cpu_maps_update_begin();
 		spin_lock(&workqueue_lock);
 		list_add(&wq->list, &workqueues);
 		spin_unlock(&workqueue_lock);
@@ -759,7 +841,7 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
 			err = create_workqueue_thread(cwq, cpu);
 			start_workqueue_thread(cwq, cpu);
 		}
-		put_online_cpus();
+		cpu_maps_update_done();
 	}
 
 	if (err) {
@@ -773,8 +855,8 @@ EXPORT_SYMBOL_GPL(__create_workqueue_key);
 static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
 {
 	/*
-	 * Our caller is either destroy_workqueue() or CPU_DEAD,
-	 * get_online_cpus() protects cwq->thread.
+	 * Our caller is either destroy_workqueue() or CPU_POST_DEAD,
+	 * cpu_add_remove_lock protects cwq->thread.
 	 */
 	if (cwq->thread == NULL)
 		return;
@@ -784,7 +866,7 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
 
 	flush_cpu_workqueue(cwq);
 	/*
-	 * If the caller is CPU_DEAD and cwq->worklist was not empty,
+	 * If the caller is CPU_POST_DEAD and cwq->worklist was not empty,
 	 * a concurrent flush_workqueue() can insert a barrier after us.
 	 * However, in that case run_workqueue() won't return and check
 	 * kthread_should_stop() until it flushes all work_struct's.
@@ -808,14 +890,14 @@ void destroy_workqueue(struct workqueue_struct *wq)
 	const cpumask_t *cpu_map = wq_cpu_map(wq);
 	int cpu;
 
-	get_online_cpus();
+	cpu_maps_update_begin();
 	spin_lock(&workqueue_lock);
 	list_del(&wq->list);
 	spin_unlock(&workqueue_lock);
 
 	for_each_cpu_mask_nr(cpu, *cpu_map)
 		cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
-	put_online_cpus();
+ 	cpu_maps_update_done();
 
 	free_percpu(wq->cpu_wq);
 	kfree(wq);
@@ -829,6 +911,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
 	unsigned int cpu = (unsigned long)hcpu;
 	struct cpu_workqueue_struct *cwq;
 	struct workqueue_struct *wq;
+	int ret = NOTIFY_OK;
 
 	action &= ~CPU_TASKS_FROZEN;
 
@@ -836,7 +919,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
 	case CPU_UP_PREPARE:
 		cpu_set(cpu, cpu_populated_map);
 	}
-
+undo:
 	list_for_each_entry(wq, &workqueues, list) {
 		cwq = per_cpu_ptr(wq->cpu_wq, cpu);
 
@@ -846,7 +929,9 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
 				break;
 			printk(KERN_ERR "workqueue [%s] for %i failed\n",
 				wq->name, cpu);
-			return NOTIFY_BAD;
+			action = CPU_UP_CANCELED;
+			ret = NOTIFY_BAD;
+			goto undo;
 
 		case CPU_ONLINE:
 			start_workqueue_thread(cwq, cpu);
@@ -854,7 +939,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
 
 		case CPU_UP_CANCELED:
 			start_workqueue_thread(cwq, -1);
-		case CPU_DEAD:
+		case CPU_POST_DEAD:
 			cleanup_workqueue_thread(cwq);
 			break;
 		}
@@ -862,11 +947,11 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
 
 	switch (action) {
 	case CPU_UP_CANCELED:
-	case CPU_DEAD:
+	case CPU_POST_DEAD:
 		cpu_clear(cpu, cpu_populated_map);
 	}
 
-	return NOTIFY_OK;
+	return ret;
 }
 
 void __init init_workqueues(void)