Re: [tip: x86/apic] smp: Provide 'setup_max_cpus' definition on UP too

From: Ingo Molnar
Date: Tue Feb 27 2024 - 04:19:18 EST



* Borislav Petkov <bp@xxxxxxxxx> wrote:

> On Mon, Feb 26, 2024 at 11:48:06AM -0000, tip-bot2 for Ingo Molnar wrote:
> > The following commit has been merged into the x86/apic branch of tip:
> >
> > Commit-ID: 429bb0269058e2e1f4ab69a0d33d374933aa15b9
> > Gitweb: https://git.kernel.org/tip/429bb0269058e2e1f4ab69a0d33d374933aa15b9
> > Author: Ingo Molnar <mingo@xxxxxxxxxx>
> > AuthorDate: Mon, 26 Feb 2024 12:07:31 +01:00
> > Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> > CommitterDate: Mon, 26 Feb 2024 12:13:40 +01:00
> >
> > smp: Provide 'setup_max_cpus' definition on UP too
> >
> > This was already defined locally by init/main.c, but let's make
> > it generic, as arch/x86/kernel/cpu/topology.c is going to make
> > use of it to have more uniform code.
> >
> > [ Keep it a C variable, not a define, because there's
> > some namespace overlap for the 'setup_max_cpus' token
> > in existing function argument names. ]
> >
> > Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Cc: linux-kernel@xxxxxxxxxxxxxxx
> > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
> > --
> > ---
> > include/linux/smp.h | 2 ++
> > init/main.c | 1 -
> > 2 files changed, 2 insertions(+), 1 deletion(-)
>
> That one needs some work:
>
> $ grep setup_max_cpus 13-37-17-randconfig-x86_64-2517.log
> ...
> ./include/linux/smp.h:221:27: warning: ‘setup_max_cpus’ defined but not used [-Wunused-const-variable=]
> $ grep setup_max_cpus 13-37-17-randconfig-x86_64-2517.log | wc -l
> 122
>
> very noisy.

Yeah, a bit sad.

So I resolved this all with using #define and (first) fixing a namespace
collision that broke with the #define:

4c8a49854130 smp: Avoid 'setup_max_cpus' namespace collision/shadowing
3c2f8859ae1c smp: Provide 'setup_max_cpus' definition on UP too
6be4ec29685c x86/apic: Build the x86 topology enumeration functions on UP APIC builds too

Thanks,

Ingo