From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cornelia Huck <cornelia.huck@de.ibm.com>
Subject: Re: [RFD driver-core] Lifetime problems of the current driver model
Date: Sat, 31 Mar 2007 18:08:06 +0200
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To: Tejun Heo <htejun@gmail.com>
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On Sat, 31 Mar 2007 12:12:48 +0900,
Tejun Heo <htejun@gmail.com> wrote:

> > Hm, but as long as dk0 is registered, it can be looked up and someone
> > could get a reference on it.
> 
> Yeah, exactly.  That's why any getting any kobject reference backed by a
> module must be accompanied by try_module_get().
> 
> int mydrv_get_dk(struct dk *dk)
> {
> 	rc = try_module_get(mydrv);
> 	if (rc)
> 		return rc;
> 	kobject_get(&dk->kobj);
> 	return 0;
> }

This works if the caller always knows which module to grab (I was
thinking about some tree-walking code).

> Exactly, in that case, module reference count must not be zero.  You and
> I are saying the same thing.  Why are we running in circle?

I hope we're not, it just makes one dizzy :)

I'll think some more about it...