Re: [PATCH] erofs: Fix EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS default logic

[Guenter Roeck]

On Thu, Aug 20, 2026 at 09:10:25PM +0800, Gao Xiang wrote:
> On Thu, Aug 20, 2026 at 05:51:08AM -0700, Guenter Roeck wrote:
> > On Thu, Aug 20, 2026 at 12:00:23PM +0200, Geert Uytterhoeven wrote:
> > > When NR_CPUS is less than 16, or when SMP is disabled, the default value
> > > of 16 is invalid.
> > > 
> > > While actual configuration picks up a sensible and valid default
> > > (NR_CPUS or 1), "make savedefconfig" will still write a line like
> > > 
> > >     CONFIG_EROFS_FS_ZIP_LZMA_DEFAULT_MAX_STREAMS=1
> > > 
> > > to the defconfig file, even if that matches the sensible default.
> > > 
> > > Avoid needlessly enlarging the defconfig files, and reduce churn for
> > > updating them, by specifying valid defaults depending on SMP and
> > > NR_CPUS.
> > > 
> > > While at it, make the prompt depend on SMP, as there is no point in
> > > asking the user about the maximum number of decompression streams if
> > > there is only one valid answer.
> > > 
> > 
> > Absolutely agree.
> 
> As I replied to Geert, unless there is a mandatory requirement
> documented that "there is no point to make a Kconfig visible if there
> is only one valid number".
> 
I would call that common sense.

Guenter

> I tend to avoid making EROFS Kconfig visibility depend on arbitrary
> architecture Kconfig options such as SMP or !SMP; SMP here is due to
> some arches make NR_CPUS = 0 if !SMP, but it doesn't need to bother
> users why a EROFS kconfig visibility has some relationship with an arch
> kconfig.
> 
> Thanks,
> Gao Xiang