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Date:   Wed, 12 Jul 2023 09:38:17 +0200
From:   Michal =?iso-8859-1?Q?Such=E1nek?= <msuchanek@suse.de>
To:     Jiri Slaby <jirislaby@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>,
        Jan Engelhardt <jengelh@inai.de>,
        Masahiro Yamada <masahiroy@kernel.org>,
        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] depmod: Handle installing modules under a prefix
Message-ID: <20230712073817.GE9196@kitsune.suse.cz>
References: <20230711153126.28876-1-msuchanek@suse.de>
 <20230711153457.29497-1-msuchanek@suse.de>
 <da2fdd15-fae1-2bf6-04e7-568c715372ce@kernel.org>
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On Wed, Jul 12, 2023 at 07:47:13AM +0200, Jiri Slaby wrote:
> On 11. 07. 23, 17:34, Michal Suchanek wrote:
> > Some distributions aim at not shipping any files in / ustside of usr.
> > 
> > The path under which kernel modules are instaleld is hardcoded to /lib
> > which conflicts with this goal.
> > 
> > When kmod provides the config command use it to determine the correct
> > module installation prefix.
> > 
> > On kmod that does not provide the command / is used as before.
> > 
> > Signed-off-by: Michal Suchanek <msuchanek@suse.de>
> > ---
> >   Makefile          | 4 +++-
> >   scripts/depmod.sh | 8 ++++----
> >   2 files changed, 7 insertions(+), 5 deletions(-)
> > 
> > diff --git a/Makefile b/Makefile
> > index 47690c28456a..b05d696f06bd 100644
> > --- a/Makefile
> > +++ b/Makefile
> > @@ -1165,7 +1165,9 @@ 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_PREFIX := $(shell kmod config | jq -r .module_prefix)
> 
> echo -e 'KERNEL_MODULE_PREFIX := $(shell kmod config | jq -r
> .module_prefix)\nall:'|make -f -
> invalid command 'config'
> parse error: Invalid numeric literal at line 1, column 5
> 
> I think you should pipe kmod's 2> /dev/null to support older kmod. Ah, but
> you'd need 2> /dev/null for jq too. That would not be good as jq might not
> be installed and a user wouldn't see the error. So instead, I would do:
> 
> $(shell kmod config &> /dev/null && kmod config | jq -r .module_prefix)

Yes, that sounds reasonable. Also would cover the potential problem of
kmod changing the error output into something that is a valid JSON in
the future.

Thanks

Michal