Hello, David. On Fri, Sep 01, 2017 at 04:40:53PM +0100, David Howells wrote: > Add a facility to the workqueue subsystem whereby an atomic_t can be > registered by a work function such that the work function dispatcher will > decrement the atomic after the work function has returned and then call > wake_up_atomic() on it if it reached 0. > > This is analogous to complete_and_exit() for kernel threads and is used to > avoid a race between notifying that a work item is about to finish and the > .text segment from a module being discarded. > > The way this is used is that the work function calls: > > dec_after_work(atomic_t *counter); > > to register the counter and then process_one_work() calls it, potentially > wakes it and clears the registration. > > The reason I've used an atomic_t rather than a completion is that (1) it > takes up less space and (2) it can monitor multiple objects.
Given how work items are used, I think this is too inviting to abuses where people build complex event chains through these counters and those chains would be completely opaque. If the goal is protecting .text of a work item, can't we just do that? Can you please describe your use case in more detail? Why can't it be done via the usual "flush from exit"? Thanks. -- tejun
