Re: [PATCH v6 1/2] depmod: Handle installing modules under a different directory

[Woody Suwalski]

Masahiro Yamada wrote:
> On Thu, Dec 7, 2023 at 4:48 AM Michal Suchanek <msuchanek@xxxxxxx> wrote:
> > Some distributions aim at shipping all files in /usr.
> >
> > The path under which kernel modules are installed is hardcoded to /lib
> > which conflicts with this goal.
> >
> > When kmod provides kmod.pc, use it to determine the correct module
> > installation path.
> >
> > With kmod that does not provide the config /lib/modules is used as
> > before.
> >
> > While pkg-config does not return an error when a variable does not exist
> > the kmod configure script puts some effort into ensuring that
> > module_directory is non-empty. With that empty module_directory from
> > pkg-config can be used to detect absence of the variable.
> >
> > Signed-off-by: Michal Suchanek <msuchanek@xxxxxxx>
> > ---
> > v6:
> >   - use ?= instead of := to make it easier to override the value
>
> "KERNEL_MODULE_DIRECTORY=/local/usr/lib/modules make modules_install"
> will override the install destination, but
> depmod will not be not aware of it.
>
> How to avoid the depmod error?
I think the depmod -b option can be used to ran depmod in an arbitrary 
location:

The following options are useful for people managing distributions:
    -b, --basedir=DIR    Use an image of a module tree.

Woody

> >   - use shorter expression for determining the module directory assuming
> >     it's non-empty
> > ---
> >   Makefile | 4 +++-
> >   1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/Makefile b/Makefile
> > index 511b5616aa41..84f32bd563d4 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -1081,7 +1081,9 @@ export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)
> >   # makefile but the argument can be passed to make if needed.
> >   #
> >
> > -MODLIB = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
> > +export KERNEL_MODULE_DIRECTORY ?= $(or $(shell pkg-config --variable=module_directory kmod 2>/dev/null),/lib/modules)
> > +
> > +MODLIB = $(INSTALL_MOD_PATH)$(KERNEL_MODULE_DIRECTORY)/$(KERNELRELEASE)
> >   export MODLIB
> >
> >   PHONY += prepare0
> > --
> > 2.42.0
>
> --
> Best Regards
> Masahiro Yamada