On Wed, 09 Jun 2010 11:32:26 -0400
James Bottomley <James.Bottomley@xxxxxxx> wrote:
> > > @@ -302,8 +330,12 @@ int pm_qos_add_notifier(int pm_qos_class, struct notifier_block *notifier)
> > > {
> > > int retval;
> > >
> > > + /* someone tried to register a blocking notifier to a
> > > + * qos object that only supports atomic ones */
> > > + BUG_ON(!pm_qos_array[pm_qos_class]->blocking_notifiers);
> > > +
> > > retval = blocking_notifier_chain_register(
> > > - pm_qos_array[pm_qos_class]->notifiers, notifier);
> > > + pm_qos_array[pm_qos_class]->blocking_notifiers, notifier);
> > >
> > > return retval;
> > > }
> >
> > Why not:
> >
> > retval = 1;
> > if(pm_qos_array[pm_qos_class]->blocking_notifiers)
> > retval = blocking_notifier_chain_register(..
> > else
> > WARN();
> > return retval;
> >
> > That way, the offending programmer could eventually fix it, without
> > having to reboot?
>
> Because there are no current users that will trip the BUG_ON ... and we
> want to keep it that way. Code doesn't go into the kernel if it BUGs on
> boot.
>
> The point about failing hard for an abuse of a kernel API isn't to trap
> current abusers because you fix those before you add it. It's to
> prevent future abuse. If your kernel BUGs under test you tend to fix
> the code, so it becomes impossible for anyone to add any users which
> abuse the API in this fashion.
>
> James
>
There are actually people who ignore WARN()ings when submitting code??
....thinking about it... Yes, that may be possible.
Cheers,
Flo
--
Only two things are infinite, the universe and human stupidity, and I'm
not sure about the former. Albert Einstein
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