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References: <20230503-virt-to-pfn-v6-4-rc1-v1-0-6c4698dcf9c8@linaro.org>
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From:   Geert Uytterhoeven <geert@linux-m68k.org>
Date:   Fri, 12 May 2023 11:57:07 +0200
Message-ID: <CAMuHMdVwusgUqBuERm1=y7fwC5CERuX8VPGdaKcJiu3fM1oNuw@mail.gmail.com>
Subject: Re: [PATCH 00/12] arch: Make virt_to_pfn into a static inline
To:     Linus Walleij <linus.walleij@linaro.org>
Cc:     Vineet Gupta <vgupta@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
        Russell King <linux@armlinux.org.uk>,
        Greg Ungerer <gerg@linux-m68k.org>,
        linux-kernel@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
        linux-snps-arc@lists.infradead.org, linux-fsdevel@vger.kernel.org,
        linux-cifs@vger.kernel.org, samba-technical@lists.samba.org,
        linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org
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Hi Linus,

On Thu, May 11, 2023 at 1:59 PM Linus Walleij <linus.walleij@linaro.org> wrote:
> This is an attempt to harden the typing on virt_to_pfn()
> and pfn_to_virt().
>
> Making virt_to_pfn() a static inline taking a strongly typed
> (const void *) makes the contract of a passing a pointer of that
> type to the function explicit and exposes any misuse of the
> macro virt_to_pfn() acting polymorphic and accepting many types
> such as (void *), (unitptr_t) or (unsigned long) as arguments
> without warnings.
>
> For symmetry, we do the same with pfn_to_virt().
>
> The problem with this inconsistent typing was pointed out by
> Russell King:
> https://lore.kernel.org/linux-arm-kernel/YoJDKJXc0MJ2QZTb@shell.armlinux.org.uk/
>
> And confirmed by Andrew Morton:
> https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/
>
> So the recognition of the problem is widespread.
>
> These platforms have been chosen as initial conversion targets:
>
> - ARC
> - ARM
> - ARM64/Aarch64
> - asm-generic (including for example x86)
> - m68k

Thanks, builds fine on m68k with MMU, and boots fine on ARAnyM,
with the extra changes I replied on patch 2/12.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds