Re: [PATCH] Enable '-Werror' by default for all kernel builds

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: "Christian König" <christian.koenig@amd.com>
Cc: Huang Rui <ray.huang@amd.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Guenter Roeck <linux@roeck-us.net>,
	"David S. Miller" <davem@davemloft.net>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-sparc <sparclinux@vger.kernel.org>
Subject: Re: [PATCH] Enable '-Werror' by default for all kernel builds
Date: Tue, 7 Sep 2021 08:58:28 +0200	[thread overview]
Message-ID: <CAMuHMdXgxSMiABLkizoTQrBXvRq20w97+LMGEgNZM8D0BsS6sw@mail.gmail.com> (raw)
In-Reply-To: <0d63f82c-7bdc-1bf0-f64b-8331291e2d4e@amd.com>

On Tue, Sep 7, 2021 at 8:25 AM Christian König <christian.koenig@amd.com> wrote:
> Am 07.09.21 um 07:32 schrieb Huang Rui:
> > On Tue, Sep 07, 2021 at 07:06:04AM +0800, Linus Torvalds wrote:
> >> [ Adding some subsystem maintainers ]
> >>
> >> On Mon, Sep 6, 2021 at 10:06 AM Guenter Roeck <linux@roeck-us.net> wrote:
> >>>> But hopefully most cases are just "people haven't cared enough" and
> >>>> easily fixed.
> >>> We'll see. For my testbed I disabled the new configuration flag
> >>> for the time being because its primary focus is boot tests, and
> >>> there won't be any boot tests if images fail to build.
> >> Sure, reasonable.
> >>
> >> I've checked a few of the build errors by doing the appropriate cross
> >> compiles, and it doesn't seem bad - but it does seem like we have a
> >> number of really pointless long-standing warnings that should have
> >> been fixed long ago.
> >>
> >> For example, looking at sparc64, there are several build errors due to
> >> those warnings now being fatal:
> >>
> >>   - drivers/gpu/drm/ttm/ttm_pool.c:386
> >>
> >>     This is a type mismatch error. It looks like __fls() on sparc64
> >> returns 'int'. And the ttm_pool.c code assumes it returns 'unsigned
> >> long'.
> >>
> >>     Oddly enough, the very line after that line does "min_t(unsigned
> >> int" to get the types in line.
> >>
> >>     So  the immediate reason is "sparc64 is different". But the deeper
> >> reason seems to be that ttm_pool.c has odd type assumptions. But that
> >> warning should have been fixed long ago, either way.
> >>
> >>     Christian/Huang? I get the feeling that both lines in that file
> >> should use the min_t(). Hmm?
> >
> > Shall we align the return type like __fls() on all the arches?
>
> I think so, yes. IIRC I was a bit surprised that it returns UL on x86. I
> mean the maximum possible value here is 63.

And ffs() returns int, like in ffs(3).

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds