Re: [Bug? Report] kref problem

Greg KH
2006-03-16T17:59:11Z

On Thu, Mar 16, 2006 at 08:45:10PM +0300, Artem B. Bityutskiy wrote:
>
> Greg KH wrote:
> >Don't statically create kobjects, it's not nice. But the real problem
> >is below...
>
> Well, that was just an example...
>
> But in real life I do use a static kobject in one case, so I'm very
> interested what should I do instead. I have a subsystem, and I want it
> to put all its stuff in a /sys/A directory. So I just define a static
> kobject for A and assign a dummy release function to it. Why is this bad?

If you use decl_subsys(), you should be fine for this. Use that instead
of trying to roll your own subsystem kobjects please. That
infrastructure was written for a reason...

> And what should I do instead? kmalloc(sizeof(struct kobject),
> GFP_KERNEL) ? I do not have a dynamic structure corresponding to my
> module. I have many data structures corresponding to entities my object
> handles and I have one static array which refers them. All is simple. I
> do not want to introduce a dynamic data structure corresponding to the
> subsystem as a whole just in order to not use static kobjects.

Data (kobjects) have a different lifespan than code (modules).
Seperating them is a good idea, and if not, your reference counting
issues can be quite nasty. See the recent EDAC fiasco for a good
example of how easy it is to mess things up in this manner.

thanks,

greg k-h