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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Fri, 16 Apr 2021 15:08:40 -0700
Message-ID: <CAPcyv4g=XyFfDZYL-brAO7LTVEc90=x7aQWar_WZtfnPx09UVQ@mail.gmail.com>
Subject: Re: [PATCH v1 1/1] libnvdimm: Don't use GUID APIs against raw buffer
To:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc:     linux-nvdimm <linux-nvdimm@lists.01.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Dave Jiang <dave.jiang@intel.com>,
        Ira Weiny <ira.weiny@intel.com>,
        "Kaneda, Erik" <erik.kaneda@intel.com>
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On Fri, Apr 16, 2021 at 1:42 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> On Fri, Apr 16, 2021 at 01:08:06PM -0700, Dan Williams wrote:
> > [ add Erik ]
> >
> > On Fri, Apr 16, 2021 at 10:36 AM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > >
> > > On Thu, Apr 15, 2021 at 05:37:54PM +0300, Andy Shevchenko wrote:
> > > > Strictly speaking the comparison between guid_t and raw buffer
> > > > is not correct. Return to plain memcmp() since the data structures
> > > > haven't changed to use uuid_t / guid_t the current state of affairs
> > > > is inconsistent. Either it should be changed altogether or left
> > > > as is.
> > >
> > > Dan, please review this one as well. I think here you may agree with me.
> >
> > You know, this is all a problem because ACPICA is using a raw buffer.
>
> And this is fine. It might be any other representation as well.
>
> > Erik, would it be possible to use the guid_t type in ACPICA? That
> > would allow NFIT to drop some ugly casts.
>
> guid_t is internal kernel type. If we ever decide to deviate from the current
> representation it wouldn't be possible in case a 3rd party is using it 1:1
> (via typedef or so).

I'm thinking something like ACPICA defining that space as a union with
the correct typing just for Linux.