Re: [PATCH] checksyscalls: ignore -Wunused-macros
From: Arnd Bergmann
Date: Mon Apr 25 2022 - 02:50:51 EST
On Mon, Apr 25, 2022 at 8:17 AM Vincent MAILHOL
> On Mon. 25 Apr 2022 at 07:17, Nathan Chancellor <nathan@xxxxxxxxxx> wrote:
> > Hi Vincent,
> > On Sat, Apr 23, 2022 at 12:17:25AM +0900, Vincent Mailhol wrote:
> > > The macros defined in this file are for testing only and are purposely
> > > not used. When compiled with W=2, both gcc and clang yield some
> > > -Wunused-macros warnings. Ignore them.
> > >
> > > Signed-off-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
> > The change itself looks fine but a couple of comments:
> > 1. Nick and I do not pick up patches, we rely on others to do so.
> > Additionally, this is not really something within our domain, despite
> > what get_maintainer.pl might say. This change should be sent to
> > either
> > Masahiro Yamada <masahiroy@xxxxxxxxxx>
> > linux-kbuild@xxxxxxxxxxxxxxx
> > or
> > Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > so that it can be applied by one of them.
> Ack. As you pointed out, I indeed just followed get_maintainer.pl.
> I will resend a v2 to the people you pointed out (and exclude you).
> > 2. I am not sure that silencing warnings from W=2 is that useful, as
> > they are unlikely to be real issues. Not to discourage you by any
> > means but it might be more useful to focus on cleaning up warnings
> > from W=1 and getting those promoted to regular build warnings.
> Normally I agree, but there is one reason to fix this W=2: this
> warning appears when building other files.
> | $ make W=2 drivers/net/dummy.o
> | CALL scripts/checksyscalls.sh
> | <stdin>:21: warning: macro "__IGNORE_stat64" is not used [-Wunused-macros]
> | <stdin>:22: warning: macro "__IGNORE_lstat64" is not used [-Wunused-macros]
> | <stdin>:75: warning: macro "__IGNORE_llseek" is not used [-Wunused-macros]
> | <stdin>:159: warning: macro "__IGNORE_madvise1" is not used [-Wunused-macros]
> (rest of the output redacted).
> When I run W=2, I want to only see the warnings of the file I am
> working on. So I find it useful to fix the W=2 warnings which
> show up when building other files to not get spammed by
> irrelevant issues and to simplify the triage.
> My initial message lacked the rationale. I will add additional
> explanations in the v2 of this patch.
I agree this is worth fixing if we want to make W=2 have any meaning at all.
Your approach is probably fine. We could try to improve this by comparing
against the list from include/uapi/asm-generic/unistd.h instead of the i386
list. I suppose that would involve rewriting the script into a simpler one,
but I'm not sure if anyone has an interest in working on this.