[PATCH 6.1 152/473] selftests/binderfs: use the Makefiles rules, not Makes implicit rules

Greg Kroah-Hartman
2024-06-06T14:14:34Z

From: John Hubbard <jhubbard@nvidia.com>

[ Upstream commit 019baf635eb6ffe8d6c1343f81788f02a7e0ed98 ]

First of all, in order to build with clang at all, one must first apply
Valentin Obst's build fix for LLVM [1]. Once that is done, then when
building with clang, via:

make LLVM=1 -C tools/testing/selftests

...the following error occurs:

clang: error: cannot specify -o when generating multiple output files

This is because clang, unlike gcc, won't accept invocations of this
form:

clang file1.c header2.h

While trying to fix this, I noticed that:

a) selftests/lib.mk already avoids the problem, and

b) The binderfs Makefile indavertently bypasses the selftests/lib.mk
build system, and quitely uses Make's implicit build rules for .c files
instead.

The Makefile attempts to set up both a dependency and a source file,
neither of which was needed, because lib.mk is able to automatically
handle both. This line:

binderfs_test: binderfs_test.c

...causes Make's implicit rules to run, which builds binderfs_test
without ever looking at lib.mk.

Fix this by simply deleting the "binderfs_test:" Makefile target and
letting lib.mk handle it instead.

[1] https://lore.kernel.org/all/20240329-selftests-libmk-llvm-rfc-v1-1-2f9ed7d1c49f@valentinobst.de/

Fixes: 6e29225af902 ("binderfs: port tests to test harness infrastructure")
Cc: Christian Brauner <brauner@kernel.org>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/filesystems/binderfs/Makefile | 2 --
1 file changed, 2 deletions(-)

diff --git a/tools/testing/selftests/filesystems/binderfs/Makefile b/tools/testing/selftests/filesystems/binderfs/Makefile
index c2f7cef919c04..eb4c3b4119348 100644
--- a/tools/testing/selftests/filesystems/binderfs/Makefile
+++ b/tools/testing/selftests/filesystems/binderfs/Makefile
@@ -3,6 +3,4 @@
CFLAGS += $(KHDR_INCLUDES) -pthread
TEST_GEN_PROGS := binderfs_test

-binderfs_test: binderfs_test.c ../../kselftest.h ../../kselftest_harness.h
-
include ../../lib.mk
--
2.43.0