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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Fri, 16 Apr 2021 09:15:34 -0700
Message-ID: <CAPcyv4jzg23CoQeqAyAR=PUjB4HG-FSnD8G0J7S=p22ANmzDMQ@mail.gmail.com>
Subject: Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use
To:     Andy Shevchenko <andy.shevchenko@gmail.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        linux-nvdimm <linux-nvdimm@lists.01.org>,
        Linux ACPI <linux-acpi@vger.kernel.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>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Len Brown <lenb@kernel.org>
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On Fri, Apr 16, 2021 at 1:58 AM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Fri, Apr 16, 2021 at 8:28 AM Dan Williams <dan.j.williams@intel.com> wrote:
> >
> > On Thu, Apr 15, 2021 at 6:59 AM Andy Shevchenko
> > <andriy.shevchenko@linux.intel.com> wrote:
> > >
> > > Strictly speaking the comparison between guid_t and raw buffer
> > > is not correct. Import GUID to variable of guid_t type and then
> > > compare.
> >
> > Hmm, what about something like the following instead, because it adds
> > safety. Any concerns about evaluating x twice in a macro should be
> > alleviated by the fact that ARRAY_SIZE() will fail the build if (x) is
> > not an array.
>
> ARRAY_SIZE doesn't check type.

See __must_be_array.

> I don't like hiding ugly casts like this.

See PTR_ERR, ERR_PTR, ERR_CAST.

There's nothing broken about the way the code currently stands, so I'd
rather try to find something to move the implementation forward than
sideways.