From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 16 May 2018 09:52:49 +0200 From: Greg Kroah-Hartman To: Masahiro Yamada Cc: Andrew Morton , Geert Uytterhoeven , Alexey Dobriyan , Lihao Liang , Linux Kernel Mailing List , Philippe Ombredanne , Pekka Enberg Subject: Re: [PATCH 3/3] types: use fixed width types without double-underscore prefix Message-ID: <20180516075249.GA3536@kroah.com> References: <1526350925-14922-1-git-send-email-yamada.masahiro@socionext.com> <1526350925-14922-3-git-send-email-yamada.masahiro@socionext.com> <20180515155925.9c16962e2b416e5f507c07b1@linux-foundation.org> <20180516062623.GA32694@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.5 (2018-04-13) X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Wed, May 16, 2018 at 03:59:01PM +0900, Masahiro Yamada wrote: > 2018-05-16 15:26 GMT+09:00 Greg Kroah-Hartman : > > On Wed, May 16, 2018 at 10:07:50AM +0900, Masahiro Yamada wrote: > >> Hi Andrew, > >> > >> 2018-05-16 7:59 GMT+09:00 Andrew Morton : > >> > On Tue, 15 May 2018 11:22:05 +0900 Masahiro Yamada wrote: > >> > > >> >> This header file is not exported. It is safe to reference types > >> >> without double-underscore prefix. > >> >> > >> > > >> > It may be safe to do this, but why is it desirable? > >> > >> > >> It is shorter. That's all. > >> If it is a noise commit, please feel free to drop it. > >> > >> > >> BTW, a large amount of kernel-space code > >> uses underscore-prefixed types. > > > > Sometimes it can/should do that. > > I agree that UAPI headers must do that. > > If you mean "it should even for non-exported code", > I have no idea why. > > > > >> I wonder if we could check it by checkpatch.pl or something... > > > > You do understand the difference between the two types and why/when they > > are needed, right? I don't think checkpatch.pl can determine if data is > > coming from userspace or not very easily to make this a simple perl > > script check :( > > > I am getting puzzled... > > It sounds like you are talking about __user or __kernel. > If so, it is a matter of sparse tool > but I believe it is a different topic. > > > If I understand correctly, > using 'u32' is safe outside of 'include/uapi/' and > arch/$(SRCARCH)/include/uapi/ > > Why can't a simple script do that? > > Am I missing something? I think we are talking past each other here :) __ types are for when the variable crosses the user/kernel boundry, that's all. ioctl structures are one such example, as are some of these specific userspace-facing types that you are changing here. We have loads of ioctl structures that are _not_ in uapi/ which is a totally different problem that I know some people are looking at fixing up, so a checkpatch.pl rule would not be good here. There's also places where data comes in from hardware that use the __ types, but those are usually a bit more rare. thanks, greg k-h