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In-Reply-To: <ba5ec856bce34eead8ba655b9bd6c54b002c40b5.camel@perches.com>
From:   Masahiro Yamada <yamada.masahiro@socionext.com>
Date:   Sun, 9 Jun 2019 22:08:33 +0900
Message-ID: <CAK7LNAToTXt71obf8NvOiuN5MnxHs+-dkCp_Midu9e6OaOqc4g@mail.gmail.com>
Subject: Re: [PATCH] media: do not use C++ style comments in uapi headers
To:     Joe Perches <joe@perches.com>
Cc:     Julia Lawall <julia.lawall@lip6.fr>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Greg KH <gregkh@linuxfoundation.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Randy Dunlap <rdunlap@infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Sun, Jun 9, 2019 at 8:57 PM Joe Perches <joe@perches.com> wrote:
>
> On Sun, 2019-06-09 at 16:14 +0900, Masahiro Yamada wrote:
> > Hi Joe,
> >
> > On Thu, Jun 6, 2019 at 2:06 AM Joe Perches <joe@perches.com> wrote:
> > > Perhaps a checkpatch change too:
> > >
> > > The first block updates unsigned only bitfields
> > > The second tests uapi definitions and suggests "__<kernel_types"
> >
> > Good.
> >
> > In addition,
> >
> > "warn if __u8, __u16, __u32, __u64 are used outside of uapi/"
> >
> > Lots of kernel-space headers use __u{8,16,32,64} instead of u{8,16,32,64}
> > just because developers often miss to understand when to use
> > the underscore-prefixed types.
>
> The problem there is that checkpatch can't know if the
> __<uapi_type> being used is for an actual uapi use or not.
>
> coccinelle could be much better at that.

Why?

u{8,16,32,64} are _exactly_ the same as __u{8,16,32,64}.
See  include/asm-generic/int-ll64.h

We just use __u{8,16,32,64} for user-space
to avoid identifier name conflict,
but we do not have reason to do so for kernel-space.


--
Best Regards
Masahiro Yamada