Commit:     071b638689464c6b39407025eedd810d5b5e6f5d
Parent:     566ec03448052c096dc3982fbe573522dc0ba479
Author:     Oleg Nesterov <[EMAIL PROTECTED]>
AuthorDate: Thu Apr 26 15:45:32 2007 -0700
Committer:  David S. Miller <[EMAIL PROTECTED]>
CommitDate: Thu Apr 26 15:45:32 2007 -0700

    [WORKQUEUE]: cancel_delayed_work: use del_timer() instead of 
    del_timer_sync() buys nothing for cancel_delayed_work(), but it is less
    efficient since it locks the timer unconditionally, and may wait for the
    completion of the delayed_work_timer_fn().
    cancel_delayed_work() == 0 means:
        before this patch:
                work->func may still be running or queued
        after this patch:
                work->func may still be running or queued, or
                delayed_work_timer_fn->__queue_work() in progress.
                The latter doesn't differ from the caller's POV,
                delayed_work_timer_fn() is called with _PENDING
                bit set.
    cancel_delayed_work() == 1 with this patch adds a new possibility:
        delayed_work->work was cancelled, but delayed_work_timer_fn
        is still running (this is only possible for the re-arming
        works on single-threaded workqueue).
        In this case the timer was re-started by work->func(), nobody
        else can do this. This in turn means that delayed_work_timer_fn
        has already passed __queue_work() (and wont't touch delayed_work)
        because nobody else can queue delayed_work->work.
    Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
    Signed-Off-By: David Howells <[EMAIL PROTECTED]>
    Signed-off-by: David S. Miller <[EMAIL PROTECTED]>
 include/linux/workqueue.h |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h
index 2a7b38d..b8abfc7 100644
--- a/include/linux/workqueue.h
+++ b/include/linux/workqueue.h
@@ -191,14 +191,15 @@ int execute_in_process_context(work_func_t fn, struct 
execute_work *);
  * Kill off a pending schedule_delayed_work().  Note that the work callback
- * function may still be running on return from cancel_delayed_work().  Run
- * flush_scheduled_work() to wait on it.
+ * function may still be running on return from cancel_delayed_work(), unless
+ * it returns 1 and the work doesn't re-arm itself. Run flush_workqueue() or
+ * cancel_work_sync() to wait on it.
 static inline int cancel_delayed_work(struct delayed_work *work)
        int ret;
-       ret = del_timer_sync(&work->timer);
+       ret = del_timer(&work->timer);
        if (ret)
        return ret;
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