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From: Vicente Feito <vicente.feito@gmail.com>
Organization: none
To: Roland Dreier <roland@topspin.com>
Subject: Re: workqueue - process context
Date: Sat, 19 Feb 2005 02:02:08 +0000
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On Saturday 19 February 2005 04:57 am, you wrote:
>     Vicente> I've been playing with workqueues, and I've found that
>     Vicente> once I unload the module, if I don't call
>     Vicente> destroy_workqueue(); then the workqueue I've created
>     Vicente> stays in the process list, [my_wq], I don't know if
>     Vicente> that's meant to be, or is it a bug, cause I believe there
>     Vicente> can be two options in here:
>
>     Vicente> 1) It's meant to be so you can unload your module and let
>     Vicente> the works run some time after you're already gone, that
>     Vicente> allows you to probe other modules or do whatever necesary
>     Vicente> without the need to wait for the workqueue to be emtpy.
>
>     Vicente> 2) It's a bug, cause the module allows to be unloaded,
>     Vicente> destroying the structs but not removing the workqueue
>     Vicente> from the process context.
>
> Not destroying its workqueue is a bug in the module just like any
> other resource leak.  It's analogous to a module allocating some
> memory with kmalloc() and not calling kfree() when it's unloaded.  If
> a module creates a workqueue, then it should call destroy_workqueue()
> when it's unloaded.
What if I need the module to be unloaded cause It's mutually exclusive with 
another module to be loaded, and I still need to run the works in a workqueue 
time before that happens? That's completely out of the picture?cause that 
might be useful.
>
> By the way, the module (or any code calling destroy_workqueue()) must
> make sure that it has race conditions that might result in work being
> submitted to the queue while it is being destroyed.
yes, I think flushing is enough, is it?

>
>  -R .
Vicente.
-
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