[tip:core/cleanups] workqueues: Improve schedule_work() documentation

[tip-bot for Bart Van Assche <bart.vanassche@gmail.com>]

Commit-ID:  5b0f437df0a3e374d26ad533eb78fe64744f55a8
Gitweb:     http://git.kernel.org/tip/5b0f437df0a3e374d26ad533eb78fe64744f55a8
Author:     Bart Van Assche <bart.vanassche@gmail.com>
AuthorDate: Thu, 30 Jul 2009 19:00:53 +0200
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Tue, 4 Aug 2009 15:21:16 +0200

workqueues: Improve schedule_work() documentation

Two important aspects of the schedule_work() function are not
yet documented:

 - that it is allowed to pass a struct work_struct * to this
   function that is already on the kernel-global workqueue;

 - the meaning of its return value.

The patch below documents both aspects.

Signed-off-by: Bart Van Assche <bart.vanassche@gmail.com>
Cc: "Greg Kroah-Hartman" <gregkh@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <200907301900.54202.bart.vanassche@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>


---
 kernel/workqueue.c |    7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 0668795..3c44b56 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -600,7 +600,12 @@ static struct workqueue_struct *keventd_wq __read_mostly;
  * schedule_work - put work task in global workqueue
  * @work: job to be done
  *
- * This puts a job in the kernel-global workqueue.
+ * Returns zero if @work was already on the kernel-global workqueue and
+ * non-zero otherwise.
+ *
+ * This puts a job in the kernel-global workqueue if it was not already
+ * queued and leaves it in the same position on the kernel-global
+ * workqueue otherwise.
  */
 int schedule_work(struct work_struct *work)
 {