On 05-12-15, 03:14, Rafael J. Wysocki wrote:
Well, almost, but not quite yet, because now the question is what prevents gov_cancel_work() from racing with dbs_work_handler().
If you can guarantee that they'll never run in parallel with each other,
They can run in parallel and that's how we fix it now: - raising skip_work to 2 makes sure that no new timer-handler can queue a new work. - After raising the value of skip_work to 2, we do cancel_work_sync(). Which will make sure that the work-handler has finished after cancel_work_sync() has returned. - At this point of time we are sure that the works and their handlers are completely killed. - All that is left is to kill all timer-handler (which might have gotten queued from the work handler, before it finished). - And we do that with gov_cancel_timers(). - And then we are in safe state, where we are guaranteed that there are no leftovers.
you probably don't need the whole counter dance. Otherwise, dbs_work_handler() should decrement the counter under the spinlock after all I suppose.
Its not required because we don't have any race around that decrement operation.