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authorTejun Heo <tj@kernel.org>2010-09-16 10:48:29 +0200
committerTejun Heo <tj@kernel.org>2010-09-19 17:51:05 +0200
commit09383498c5d35262e643bfdbae84826177a3c624 (patch)
treeec75ee767bff28cabbd1d1b82cfc3457147dda33 /kernel/workqueue.c
parentbaf59022c37d43f202e62d5130e4bac5e825b426 (diff)
downloadlinux-09383498c5d35262e643bfdbae84826177a3c624.tar.bz2
workqueue: implement flush[_delayed]_work_sync()
Implement flush[_delayed]_work_sync(). These are flush functions which also make sure no CPU is still executing the target work from earlier queueing instances. These are similar to cancel[_delayed]_work_sync() except that the target work item is flushed instead of cancelled. Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r--kernel/workqueue.c56
1 files changed, 56 insertions, 0 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 33d31d768706..19e4bc15ee99 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2435,6 +2435,41 @@ static bool wait_on_work(struct work_struct *work)
return ret;
}
+/**
+ * flush_work_sync - wait until a work has finished execution
+ * @work: the work to flush
+ *
+ * Wait until @work has finished execution. On return, it's
+ * guaranteed that all queueing instances of @work which happened
+ * before this function is called are finished. In other words, if
+ * @work hasn't been requeued since this function was called, @work is
+ * guaranteed to be idle on return.
+ *
+ * RETURNS:
+ * %true if flush_work_sync() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_work_sync(struct work_struct *work)
+{
+ struct wq_barrier barr;
+ bool pending, waited;
+
+ /* we'll wait for executions separately, queue barr only if pending */
+ pending = start_flush_work(work, &barr, false);
+
+ /* wait for executions to finish */
+ waited = wait_on_work(work);
+
+ /* wait for the pending one */
+ if (pending) {
+ wait_for_completion(&barr.done);
+ destroy_work_on_stack(&barr.work);
+ }
+
+ return pending || waited;
+}
+EXPORT_SYMBOL_GPL(flush_work_sync);
+
/*
* Upon a successful return (>= 0), the caller "owns" WORK_STRUCT_PENDING bit,
* so this work can't be re-armed in any way.
@@ -2539,6 +2574,27 @@ bool flush_delayed_work(struct delayed_work *dwork)
EXPORT_SYMBOL(flush_delayed_work);
/**
+ * flush_delayed_work_sync - wait for a dwork to finish
+ * @dwork: the delayed work to flush
+ *
+ * Delayed timer is cancelled and the pending work is queued for
+ * execution immediately. Other than timer handling, its behavior
+ * is identical to flush_work_sync().
+ *
+ * RETURNS:
+ * %true if flush_work_sync() waited for the work to finish execution,
+ * %false if it was already idle.
+ */
+bool flush_delayed_work_sync(struct delayed_work *dwork)
+{
+ if (del_timer_sync(&dwork->timer))
+ __queue_work(raw_smp_processor_id(),
+ get_work_cwq(&dwork->work)->wq, &dwork->work);
+ return flush_work_sync(&dwork->work);
+}
+EXPORT_SYMBOL(flush_delayed_work_sync);
+
+/**
* cancel_delayed_work_sync - cancel a delayed work and wait for it to finish
* @dwork: the delayed work cancel
*