[PATCH wq#for-next] workqueue: Clarify that schedule_on_each_cpu is synchronous

[Tejun Heo <tj@kernel.org>]

The documentation for schedule_on_each_cpu() states that it calls a
function on each online CPU from keventd.  This can easily be
interpreted as an asyncronous call because the description does not
mention that flush_work is called.  Clarify that it is synchronous.

tj: rephrased a bit

Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
Commited somewhat rephrased version.  Thank you.

 kernel/workqueue.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 2c6871c..eb5c197 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -2676,13 +2676,15 @@ int schedule_delayed_work_on(int cpu,
 EXPORT_SYMBOL(schedule_delayed_work_on);

 /**
- * schedule_on_each_cpu - call a function on each online CPU from keventd
+ * schedule_on_each_cpu - execute a function synchronously on each online CPU
  * @func: the function to call
  *
- * Returns zero on success.
- * Returns -ve errno on failure.
- *
+ * schedule_on_each_cpu() executes @func on each online CPU using the
+ * system workqueue and blocks until all CPUs have completed.
  * schedule_on_each_cpu() is very slow.
+ *
+ * RETURNS:
+ * 0 on success, -errno on failure.
  */
 int schedule_on_each_cpu(work_func_t func)
 {
-- 
1.7.1