Re: [PATCH] Illustration of warning explosion silliness

Andrew Morton
2006-09-28T05:04:59Z

On Thu, 28 Sep 2006 00:54:31 -0400
Jeff Garzik <jeff@garzik.org> wrote:

> Andrew Morton wrote:
> > On Wed, 27 Sep 2006 21:36:28 -0700
> > Andrew Morton <akpm@osdl.org> wrote:
> >
> >> device_for_each_child()
> >
> > All that being said, device_for_each_child() is rather broken by design.
> > It walks a list of items applying a function to them and bales out on
> > first-error.
>
> Or, like scsi_sysfs.c, it stops when it meets the first match. Which is
> a common thing to do.

That code is flakey. Trace through all the called functions, see all the
errors which get ignored.

>
> > There's no way in which the caller can know which items have been operated
> > on, nor which items have yet to be operated on, nor which item experienced
> > the failure. Any caller which is serious about error recovery presumably
> > won't use it, unless the callback function happens to be something which
> > makes no state changes.
>
> A simple integer return error doesn't tell you all that information
> either. The actor must obviously store that additional information
> somewhere, if it cares.

Yup.

> But whatever. I give up.

That's the spirit ;)

> I'm going back to working on the libata
> warnings each build spits out (iomap).

Thanks.