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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Thu, 8 Apr 2021 14:24:50 +0300
Message-ID: <CAHp75Vdyug5zbSpGSDEK9hUY+y+ZLDeAyLsc2HAjEzczCpDOSQ@mail.gmail.com>
Subject: Re: [PATCH v4 11/18] asm-generic/io.h: implement pci_remap_cfgspace
 using ioremap_np
To:     Hector Martin <marcan@marcan.st>
Cc:     Will Deacon <will@kernel.org>,
        linux-arm Mailing List <linux-arm-kernel@lists.infradead.org>,
        Marc Zyngier <maz@kernel.org>, Rob Herring <robh@kernel.org>,
        Arnd Bergmann <arnd@kernel.org>,
        Olof Johansson <olof@lixom.net>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Mark Kettenis <mark.kettenis@xs4all.nl>,
        Tony Lindgren <tony@atomide.com>,
        Mohamed Mediouni <mohamed.mediouni@caramail.com>,
        Stan Skowronek <stan@corellium.com>,
        Alexander Graf <graf@amazon.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christoph Hellwig <hch@infradead.org>,
        "David S. Miller" <davem@davemloft.net>,
        devicetree <devicetree@vger.kernel.org>,
        Linux Documentation List <linux-doc@vger.kernel.org>,
        Linux-Arch <linux-arch@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Thu, Apr 8, 2021 at 2:01 PM Hector Martin <marcan@marcan.st> wrote:
> On 08/04/2021 06.03, Will Deacon wrote:
> >> I would rewrite above as
> >>
> >> void __iomem *ret;
> >>
> >> ret = ioremap_np(offset, size);
> >> if (ret)
> >>    return ret;
> >>
> >> return ioremap(offset, size);
> >
> > Looks like it might be one of those rare occasions where the GCC ternary if
> > extension thingy comes in handy:
> >
> >       return ioremap_np(offset, size) ?: ioremap(offset, size);
>
> Today I learned that this one is kosher in kernel code. Handy! Let's go
> with that.

It depends on the maintainer. Greg, for example, doesn't  like this. I
have no strong opinion (I use both variants on case-by-case basis),
though I think in headers better to spell out all conditionals
clearly.

-- 
With Best Regards,
Andy Shevchenko