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Date:   Sun, 10 Dec 2023 22:07:48 +0100
From:   Michal =?iso-8859-1?Q?Such=E1nek?= <msuchanek@suse.de>
To:     Masahiro Yamada <masahiroy@kernel.org>
Cc:     linux-modules@vger.kernel.org, Takashi Iwai <tiwai@suse.com>,
        Lucas De Marchi <lucas.de.marchi@gmail.com>,
        Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>,
        Jiri Slaby <jslaby@suse.com>, Jan Engelhardt <jengelh@inai.de>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Nicolas Schier <nicolas@fjasle.eu>,
        linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 1/2] depmod: Handle installing modules under a
 different directory
Message-ID: <20231210210748.GM9696@kitsune.suse.cz>
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Hello!

On Mon, Dec 11, 2023 at 03:43:44AM +0900, Masahiro Yamada wrote:
> On Thu, Dec 7, 2023 at 4:48 AM Michal Suchanek <msuchanek@suse.de> 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@suse.de>
> > ---
> > 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.

At the same time if you know what you are doing you can build a src rpm
for another system that uses a different location.

> How to avoid the depmod error?

Not override the variable?

Thanks

Michal

> >  - 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