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-rw-r--r--kernel/workqueue.c95
1 files changed, 92 insertions, 3 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index b7bb37a..918d552 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -46,6 +46,7 @@ struct cpu_workqueue_struct {
struct workqueue_struct *wq;
struct task_struct *thread;
+ struct work_struct *current_work;
int run_depth; /* Detect run_workqueue() recursion depth */
@@ -120,6 +121,7 @@ static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work
&& work_pending(work)
&& !list_empty(&work->entry)) {
work_func_t f = work->func;
+ cwq->current_work = work;
list_del_init(&work->entry);
spin_unlock_irqrestore(&cwq->lock, flags);
@@ -128,6 +130,7 @@ static int __run_work(struct cpu_workqueue_struct *cwq, struct work_struct *work
f(work);
spin_lock_irqsave(&cwq->lock, flags);
+ cwq->current_work = NULL;
ret = 1;
}
spin_unlock_irqrestore(&cwq->lock, flags);
@@ -166,6 +169,17 @@ int fastcall run_scheduled_work(struct work_struct *work)
}
EXPORT_SYMBOL(run_scheduled_work);
+static void insert_work(struct cpu_workqueue_struct *cwq,
+ struct work_struct *work, int tail)
+{
+ set_wq_data(work, cwq);
+ if (tail)
+ list_add_tail(&work->entry, &cwq->worklist);
+ else
+ list_add(&work->entry, &cwq->worklist);
+ wake_up(&cwq->more_work);
+}
+
/* Preempt must be disabled. */
static void __queue_work(struct cpu_workqueue_struct *cwq,
struct work_struct *work)
@@ -173,9 +187,7 @@ static void __queue_work(struct cpu_workqueue_struct *cwq,
unsigned long flags;
spin_lock_irqsave(&cwq->lock, flags);
- set_wq_data(work, cwq);
- list_add_tail(&work->entry, &cwq->worklist);
- wake_up(&cwq->more_work);
+ insert_work(cwq, work, 1);
spin_unlock_irqrestore(&cwq->lock, flags);
}
@@ -305,6 +317,7 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq)
struct work_struct, entry);
work_func_t f = work->func;
+ cwq->current_work = work;
list_del_init(cwq->worklist.next);
spin_unlock_irqrestore(&cwq->lock, flags);
@@ -325,6 +338,7 @@ static void run_workqueue(struct cpu_workqueue_struct *cwq)
}
spin_lock_irqsave(&cwq->lock, flags);
+ cwq->current_work = NULL;
}
cwq->run_depth--;
spin_unlock_irqrestore(&cwq->lock, flags);
@@ -449,6 +463,75 @@ void fastcall flush_workqueue(struct workqueue_struct *wq)
}
EXPORT_SYMBOL_GPL(flush_workqueue);
+static void wait_on_work(struct cpu_workqueue_struct *cwq,
+ struct work_struct *work)
+{
+ struct wq_barrier barr;
+ int running = 0;
+
+ spin_lock_irq(&cwq->lock);
+ if (unlikely(cwq->current_work == work)) {
+ init_wq_barrier(&barr);
+ insert_work(cwq, &barr.work, 0);
+ running = 1;
+ }
+ spin_unlock_irq(&cwq->lock);
+
+ if (unlikely(running)) {
+ mutex_unlock(&workqueue_mutex);
+ wait_for_completion(&barr.done);
+ mutex_lock(&workqueue_mutex);
+ }
+}
+
+/**
+ * flush_work - block until a work_struct's callback has terminated
+ * @wq: the workqueue on which the work is queued
+ * @work: the work which is to be flushed
+ *
+ * flush_work() will attempt to cancel the work if it is queued. If the work's
+ * callback appears to be running, flush_work() will block until it has
+ * completed.
+ *
+ * flush_work() is designed to be used when the caller is tearing down data
+ * structures which the callback function operates upon. It is expected that,
+ * prior to calling flush_work(), the caller has arranged for the work to not
+ * be requeued.
+ */
+void flush_work(struct workqueue_struct *wq, struct work_struct *work)
+{
+ struct cpu_workqueue_struct *cwq;
+
+ mutex_lock(&workqueue_mutex);
+ cwq = get_wq_data(work);
+ /* Was it ever queued ? */
+ if (!cwq)
+ goto out;
+
+ /*
+ * This work can't be re-queued, and the lock above protects us
+ * from take_over_work(), no need to re-check that get_wq_data()
+ * is still the same when we take cwq->lock.
+ */
+ spin_lock_irq(&cwq->lock);
+ list_del_init(&work->entry);
+ work_release(work);
+ spin_unlock_irq(&cwq->lock);
+
+ if (is_single_threaded(wq)) {
+ /* Always use first cpu's area. */
+ wait_on_work(per_cpu_ptr(wq->cpu_wq, singlethread_cpu), work);
+ } else {
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ wait_on_work(per_cpu_ptr(wq->cpu_wq, cpu), work);
+ }
+out:
+ mutex_unlock(&workqueue_mutex);
+}
+EXPORT_SYMBOL_GPL(flush_work);
+
static struct task_struct *create_workqueue_thread(struct workqueue_struct *wq,
int cpu, int freezeable)
{
@@ -650,6 +733,12 @@ void flush_scheduled_work(void)
}
EXPORT_SYMBOL(flush_scheduled_work);
+void flush_work_keventd(struct work_struct *work)
+{
+ flush_work(keventd_wq, work);
+}
+EXPORT_SYMBOL(flush_work_keventd);
+
/**
* cancel_rearming_delayed_workqueue - reliably kill off a delayed work whose handler rearms the delayed work.
* @wq: the controlling workqueue structure
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