linux-kernel - Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use

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Date:   Fri, 16 Apr 2021 20:33:55 +0300
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Dan Williams <dan.j.williams@...el.com>
Cc:     linux-nvdimm <linux-nvdimm@...ts.01.org>,
        Linux ACPI <linux-acpi@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Vishal Verma <vishal.l.verma@...el.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Ira Weiny <ira.weiny@...el.com>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>
Subject: Re: [PATCH v1 1/1] ACPI: NFIT: Import GUID before use

On Fri, Apr 16, 2021 at 09:15:34AM -0700, Dan Williams wrote:
> On Fri, Apr 16, 2021 at 1:58 AM Andy Shevchenko
> <andy.shevchenko@...il.com> wrote:
> > On Fri, Apr 16, 2021 at 8:28 AM Dan Williams <dan.j.williams@...el.com> wrote:
> > > On Thu, Apr 15, 2021 at 6:59 AM Andy Shevchenko
> > > <andriy.shevchenko@...ux.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.

It's special, i.e. error pointer case. We don't handle such here.

> 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.

Submit a patch then. I rest my case b/c I consider that ugly castings worse
than additional API call, although it's not ideal.

-- 
With Best Regards,
Andy Shevchenko