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From:   Nick Desaulniers <ndesaulniers@google.com>
Date:   Tue, 5 Dec 2023 14:25:43 -0800
Message-ID: <CAKwvOd=bZvLz4yRqet6Hv2O9iZYfGr=xiwfk+-MAasPjK7XnWA@mail.gmail.com>
Subject: Re: [PATCH] lib/string: shrink lib/string.i via IWYU
To:     Randy Dunlap <rdunlap@infradead.org>
Cc:     Andy Shevchenko <andy@kernel.org>,
        Al Viro <viro@zeniv.linux.org.uk>, tanzirh@google.com,
        Kees Cook <keescook@chromium.org>,
        linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
        Nick DeSaulniers <nnn@google.com>,
        Andrew Morton <akpm@linux-foundation.org>, llvm@lists.linux.dev
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On Tue, Dec 5, 2023 at 2:10=E2=80=AFPM Randy Dunlap <rdunlap@infradead.org>=
 wrote:
>
> I have an unpublished Linux Best Known Practices txt file with
> this "rule" and some other info that I have collected over a few
> years. I wouldn't say that it's up to date. Anyway, it's copied below
> FWIW.
> Generic drivers should not (do not) #include header files from
> <asm-generic>. Only arch code and arch-specific drivers do that.

Ok, that confirms my understanding.  We had picked up on that
convention, but had missed the one below.

>
> Don't use <asm/header.h> in generic driver code. Instead use
> some <linux/header.h> that then #includes <asm/header.h>.
> asm/ headers are implementation; linux/ headers are API.

Ah, yeah, that's what we missed.

---
You should publish you doc somewhere, it can be helpful to refer back
to them when you're on a different machine or to point someone else
to.

I keep notes like this myself for debugging LLVM:
https://github.com/ClangBuiltLinux/llvm-dev-conf-2020/issues/3 (and
recently gcc: https://github.com/ClangBuiltLinux/llvm-dev-conf-2020/issues/=
4)
--=20
Thanks,
~Nick Desaulniers