Re: event sequencing

[Greg KH <greg@kroah.com>]

On Mon, Feb 28, 2005 at 04:13:23PM -0500, Jon Smirl wrote:
> On Mon, 28 Feb 2005 11:56:43 -0800, Greg KH <greg@kroah.com> wrote:
> > I like the idea of your patch, but I think it breaks when we remove the
> > class_device device, right?  Or if we remove the parent class_device
> > first.
> 
> Added code to inc the parent's ref count. 
> BTW if parent is NULL the later call to
> class_device_add_attrs(class_dev); is going to trap.
> 
> [jonsmirl@jonsmirl base]$ bk diffs -u
> === class.c 1.57 vs edited ==> --- 1.57/drivers/base/class.c   2004-12-21 19:29:34 -05:00
> +++ edited/class.c      2005-02-28 16:10:04 -05:00
> @@ -417,8 +417,9 @@
> 
>         /* first, register with generic layer. */
>         kobject_set_name(&class_dev->kobj, "%s", class_dev->class_id);
> -       if (parent)
> +       if (parent && !class_dev->kobj.parent)
>                 class_dev->kobj.parent = &parent->subsys.kset.kobj;
> +       class_dev->kobj.parent = kobject_get(class_dev->kobj.parent);
> 
>         if ((error = kobject_add(&class_dev->kobj)))
>                 goto register_done;
> @@ -467,6 +468,7 @@
>         class_device_driver_unlink(class_dev);
>         class_device_remove_attrs(class_dev);
> 
> +       kobject_put(class_dev->kobj.parent);
>         kobject_del(&class_dev->kobj);
> 
>         if (parent)

And this works ok for you?  Hm, we don't really need to walk class
devices in "order" like we do for real devices, so this might be
acceptable.  But it just feels wrong, and I _know_ people will get this
wrong (everyone gets the class code wrong the first time they do it.)
We're trying to make this simpler, not more complex, with hidden "if you
set this pointer before you call a function, this magic happens..."

Anyway, let's do this properly, it's on the todo list, and will get done
in a few weeks.

thanks,

greg k-h


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