[PATCH] m68k: Define NR_CPUS to 1

[PATCH] m68k: Define NR_CPUS to 1

[Uwe Kleine-König]

This fixes a Kconfig warning

	fs/erofs/Kconfig:137:warning: range is invalid

which originates from EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS using
NR_CPUS which up to now didn't exist for ARCH=m68k. All other
architectures define this symbol, so fix the outlier.

Fixes: c9b47e6b2311 ("erofs: cap LZMA stream pool size")
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
---
 arch/m68k/Kconfig.cpu | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
index 148f8a79d206..5a58cc13229e 100644
--- a/arch/m68k/Kconfig.cpu
+++ b/arch/m68k/Kconfig.cpu
@@ -549,6 +549,10 @@ config CACHE_COPYBACK
 endchoice
 endif # HAVE_CACHE_CB
 
+config NR_CPUS
+	int
+	default "1"
+
 # Coldfire cores that do not have a data cache configured can do coherent DMA.
 config COLDFIRE_COHERENT_DMA
 	bool

base-commit: 95d6a9ccef99117115e41e9adb271243bd5e985b
-- 
2.55.0.11.g153666a7d9bb

Re: [PATCH] m68k: Define NR_CPUS to 1

[Geert Uytterhoeven]

Hi Uwe,

Thanks for your patch!

On Fri, 31 Jul 2026 at 11:50, Uwe Kleine-König <ukleinek@kernel.org> wrote:
> This fixes a Kconfig warning
>
>         fs/erofs/Kconfig:137:warning: range is invalid
>
> which originates from EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS using
> NR_CPUS which up to now didn't exist for ARCH=m68k. All other
> architectures define this symbol, so fix the outlier.

Apart from the Kconfig warning, this also
  1. Breaks pressing "ENTER" in "make oldconfig" to apply a sensible
     default value, just repeating the question ad infinitum instead
     (the default is 16),
  2. "make olddefconfig" sets it to literal NR_CPUS, which is invalid, too.

> Fixes: c9b47e6b2311 ("erofs: cap LZMA stream pool size")
> Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>

> --- a/arch/m68k/Kconfig.cpu
> +++ b/arch/m68k/Kconfig.cpu
> @@ -549,6 +549,10 @@ config CACHE_COPYBACK
>  endchoice
>  endif # HAVE_CACHE_CB
>
> +config NR_CPUS
> +       int
> +       default "1"

While this does fix the issues on m68k, I don't think this is the
right fix:
  - NR_CPUS depends on SMP on most architectures, so you do not get
     the "range is invalid" warning on non-SMP, but NR_CPUS is zero.
    Hence I managed to reproduce the two issues above (albeit 2 with
    CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS=0) with a non-SMP
    ARM config.
  - Kconfig logic using NR_CPUS typically includes a check for SMP, too.

So I think EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS should be fixed
instead.

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

Re: [PATCH] m68k: Define NR_CPUS to 1

[Uwe Kleine-König]

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On Mon, Aug 03, 2026 at 09:58:14AM +0200, Geert Uytterhoeven wrote:
> Hi Uwe,
> 
> Thanks for your patch!
> 
> On Fri, 31 Jul 2026 at 11:50, Uwe Kleine-König <ukleinek@kernel.org> wrote:
> > This fixes a Kconfig warning
> >
> >         fs/erofs/Kconfig:137:warning: range is invalid
> >
> > which originates from EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS using
> > NR_CPUS which up to now didn't exist for ARCH=m68k. All other
> > architectures define this symbol, so fix the outlier.
> 
> Apart from the Kconfig warning, this also
>   1. Breaks pressing "ENTER" in "make oldconfig" to apply a sensible
>      default value, just repeating the question ad infinitum instead
>      (the default is 16),
>   2. "make olddefconfig" sets it to literal NR_CPUS, which is invalid, too.
> 
> > Fixes: c9b47e6b2311 ("erofs: cap LZMA stream pool size")
> > Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
> 
> > --- a/arch/m68k/Kconfig.cpu
> > +++ b/arch/m68k/Kconfig.cpu
> > @@ -549,6 +549,10 @@ config CACHE_COPYBACK
> >  endchoice
> >  endif # HAVE_CACHE_CB
> >
> > +config NR_CPUS
> > +       int
> > +       default "1"
> 
> While this does fix the issues on m68k, I don't think this is the
> right fix:
>   - NR_CPUS depends on SMP on most architectures, so you do not get
>      the "range is invalid" warning on non-SMP, but NR_CPUS is zero.
>     Hence I managed to reproduce the two issues above (albeit 2 with
>     CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS=0) with a non-SMP
>     ARM config.
>   - Kconfig logic using NR_CPUS typically includes a check for SMP, too.
> 
> So I think EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS should be fixed
> instead.

Agreed, probably it should depend on SMP, too.

Thanks for your feedback
Uwe

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Re: [PATCH] m68k: Define NR_CPUS to 1

[Geert Uytterhoeven]

On Mon, 3 Aug 2026 at 10:56, Uwe Kleine-König <ukleinek@kernel.org> wrote:
> On Mon, Aug 03, 2026 at 09:58:14AM +0200, Geert Uytterhoeven wrote:
> > On Fri, 31 Jul 2026 at 11:50, Uwe Kleine-König <ukleinek@kernel.org> wrote:
> > > This fixes a Kconfig warning
> > >
> > >         fs/erofs/Kconfig:137:warning: range is invalid
> > >
> > > which originates from EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS using
> > > NR_CPUS which up to now didn't exist for ARCH=m68k. All other
> > > architectures define this symbol, so fix the outlier.
> >
> > Apart from the Kconfig warning, this also
> >   1. Breaks pressing "ENTER" in "make oldconfig" to apply a sensible
> >      default value, just repeating the question ad infinitum instead
> >      (the default is 16),
> >   2. "make olddefconfig" sets it to literal NR_CPUS, which is invalid, too.
> >
> > > Fixes: c9b47e6b2311 ("erofs: cap LZMA stream pool size")
> > > Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
> >
> > > --- a/arch/m68k/Kconfig.cpu
> > > +++ b/arch/m68k/Kconfig.cpu
> > > @@ -549,6 +549,10 @@ config CACHE_COPYBACK
> > >  endchoice
> > >  endif # HAVE_CACHE_CB
> > >
> > > +config NR_CPUS
> > > +       int
> > > +       default "1"
> >
> > While this does fix the issues on m68k, I don't think this is the
> > right fix:
> >   - NR_CPUS depends on SMP on most architectures, so you do not get
> >      the "range is invalid" warning on non-SMP, but NR_CPUS is zero.
> >     Hence I managed to reproduce the two issues above (albeit 2 with
> >     CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS=0) with a non-SMP
> >     ARM config.
> >   - Kconfig logic using NR_CPUS typically includes a check for SMP, too.
> >
> > So I think EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS should be fixed
> > instead.
>
> Agreed, probably it should depend on SMP, too.

Since the underlying issue can be fixed by depending on SMP, but the
warning would still be there[1], I decided to bite the bullet and take
your patch as a fix for v7.2.

Reviewed-by: Geert Uytterhoeven <geert@linux-m68k.org>
i.e. will queue in the m68k tree for v7.2.

[1] https://lore.kernel.org/CAMuHMdWQLwgShMK7G-6soiZxtRPYWLizBLRdouwxFUcFXUJM-Q@mail.gmail.com

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