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Date:   Wed, 6 Dec 2023 00:01:56 +0200
From:   Andy Shevchenko <andy@kernel.org>
To:     Nick Desaulniers <ndesaulniers@google.com>
Cc:     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
Subject: Re: [PATCH] lib/string: shrink lib/string.i via IWYU
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References: <20231205-libstringheader-v1-1-7f9c573053a7@gmail.com>
 <20231205213807.GE1674809@ZenIV>
 <CAKwvOd=2VASkaLvjU+7kkbvhu2CimYn5KUGJBDRePyUhtrNK2Q@mail.gmail.com>
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On Tue, Dec 05, 2023 at 01:51:10PM -0800, Nick Desaulniers wrote:
> On Tue, Dec 5, 2023 at 1:38 PM Al Viro <viro@zeniv.linux.org.uk> wrote:
> > On Tue, Dec 05, 2023 at 08:58:53PM +0000, tanzirh@google.com wrote:

...

> > > IWYU is implemented using the IWYUScripts github repository which is a tool that is
> > > currently undergoing development. These changes seek to improve build times.
> > >
> > > This change to lib/string.c resulted in a preprocessed size of
> > > lib/string.i from 26371 lines to 5232 lines (-80%).
> >
> > It also breeds includes of asm/*.h, by the look of the output, which is
> > not a good thing in general ;-/  E.g. #include <asm/uaccess.h> *anywhere*
> > outside of linux/uaccess.h is a bad idea.
> 
> It's not clear to me when it's ok to #include <asm/*.h>.  Is there a
> convention here that I'm missing?

The mandatory ones can be used, but not all of them.
In some cases you even must include asm and not linux
(unaligned.h, byteorder.h, maybe others...).

As I told, it comes with experience, we lack of the
respective documentation (or file which is good for
automation checks, like with IWYU).

-- 
With Best Regards,
Andy Shevchenko