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Message-ID: <3de9a64e-6f27-8f76-9626-6ee082d382ea@digikod.net>
Date:   Fri, 5 Aug 2022 19:16:04 +0200
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To:     Guillaume Tucker <guillaume.tucker@collabora.com>,
        Shuah Khan <shuah@kernel.org>
Cc:     Anders Roxell <anders.roxell@linaro.org>, Tim.Bird@sony.com,
        kernel@collabora.com, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        linux-security-module@vger.kernel.org
References: <a459363217b1847c0f206a5dbdf181cb21cf3d0c.1659557290.git.guillaume.tucker@collabora.com>
 <f1fc4e6e-e2a6-3ec7-2d3b-215111a4b9ae@digikod.net>
 <76a2ac43-6e3d-0b62-7c8c-eec5f247f8f8@collabora.com>
From:   =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= <mic@digikod.net>
Subject: Re: [PATCH] selftests/landlock: fix broken include of
 linux/landlock.h
In-Reply-To: <76a2ac43-6e3d-0b62-7c8c-eec5f247f8f8@collabora.com>
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On 04/08/2022 21:38, Guillaume Tucker wrote:
> On 04/08/2022 12:36, Mickaël Salaün wrote:
>>
>> On 03/08/2022 22:13, Guillaume Tucker wrote:
>>> Revert part of the earlier changes to fix the kselftest build when
>>> using a sub-directory from the top of the tree as this broke the
>>> landlock test build as a side-effect when building with "make -C
>>> tools/testing/selftests/landlock".
>>>
>>> Reported-by: Mickaël Salaün <mic@digikod.net>
>>> Fixes: a917dd94b832 ("selftests/landlock: drop deprecated headers dependency")
>>> Fixes: f2745dc0ba3d ("selftests: stop using KSFT_KHDR_INSTALL")
>>> Signed-off-by: Guillaume Tucker <guillaume.tucker@collabora.com>
>>> ---
>>>    tools/testing/selftests/landlock/Makefile | 7 +++++--
>>>    1 file changed, 5 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/tools/testing/selftests/landlock/Makefile b/tools/testing/selftests/landlock/Makefile
>>> index a6959df28eb0..02868ac3bc71 100644
>>> --- a/tools/testing/selftests/landlock/Makefile
>>> +++ b/tools/testing/selftests/landlock/Makefile
>>> @@ -9,10 +9,13 @@ TEST_GEN_PROGS := $(src_test:.c=)
>>>    TEST_GEN_PROGS_EXTENDED := true
>>>      OVERRIDE_TARGETS := 1
>>> +top_srcdir := ../../../..
>>
>> Not sure it changes much, but most other selftests Makefiles use "top_srcdir = ../../../.." (without ":="). Why this change?
> 
> I didn't simply apply your diff but edited the file by hand to
> test various combinations and see what side effects it might
> have.  So when I added top_srcdir I typed it by hand and used :=
> as a reflex since it's the standard way of assigning variables.
> Using = instead only makes a difference when the r-value has
> something dynamic as it will be re-evaluated every time it's
> used.  So for constant values, I guess it's more of a question of
> coding style and conventions.  Maybe all the top_srcdir variables
> should be changed to := but that's unnecessary churn...  Either
> way, it's benign.
> 
> Shuah, feel free to change this back to = in this particular case
> if it's more consistent with other Makefiles.  Consistency is
> often better than arbitrary rules.  Or conversely, change to :=
> for the khdr_dir definition...  Entirely up to you I think.

Looks good to me, thanks! Shuah, feel free to add
Signed-off-by: Mickaël Salaün <mic@digikod.net>

> 
> Thanks,
> Guillaume
> 
>>>    include ../lib.mk
>>>    +khdr_dir = $(top_srcdir)/usr/include
>>> +
>>>    $(OUTPUT)/true: true.c
>>>        $(LINK.c) $< $(LDLIBS) -o $@ -static
>>>    -$(OUTPUT)/%_test: %_test.c ../kselftest_harness.h common.h
>>> -    $(LINK.c) $< $(LDLIBS) -o $@ -lcap
>>> +$(OUTPUT)/%_test: %_test.c $(khdr_dir)/linux/landlock.h ../kselftest_harness.h common.h
>>> +    $(LINK.c) $< $(LDLIBS) -o $@ -lcap -I$(khdr_dir)
>