Re: [PATCH for-7.1 0/9] spapr: add drc->index, remove spapr_drc_index()

[David Gibson]

On Mon, Mar 21, 2022 at 04:58:47AM -0300, Daniel Henrique Barboza wrote:
> 
> 
> On 3/21/22 00:55, David Gibson wrote:
> > On Fri, Mar 18, 2022 at 02:33:11PM -0300, Daniel Henrique Barboza wrote:
> > > Hi,
> > > 
> > > I decided to make this change after realizing that (1) spapr_drc_index()
> > > always return the same index value for the DRC regardless of machine or
> > > device state and (2) we call spapr_drc_index() a lot throughout the
> > > spapr code.
> > 
> > Hmm.. so, spapr_drc_index() wasn't ever intended as an abstraction
> > point.  Rather, it's just there as a matter of data redundancy.  The
> > index can be derived from the drc->id and the type.  Unless there's a
> > compelling reason otherwise, it's usually a good idea to store data in
> > just one form (if there's more it's an opportunity for bugs to let it
> > get out of sync).
> 
> 
> Hmm what if we store drc->index instead and derive drc->id from it? drc->index
> is read from several places, while drc->id is used just in spapr_drc_name() to
> write the DT (via spapr_dt_drc()).

That could work.  It's still slightly redundant since the type part of
the index can be derived from the class, but I think it's not unreasonable.

-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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