[PATCH v2] lib: PRIME_NUMBERS_KUNIT_TEST should not select PRIME_NUMBERS

[Geert Uytterhoeven]

Enabling a (modular) test should not silently enable additional kernel
functionality, as that may increase the attack vector of a product.

Fix this by making PRIME_NUMBERS_KUNIT_TEST depend on PRIME_NUMBERS
instead of selecting it.

After this, one can safely enable CONFIG_KUNIT_ALL_TESTS=m to build
modules for all appropriate tests for ones system, without pulling in
extra unwanted functionality, while still allowing a tester to manually
enable PRIME_NUMBERS and this test suite on a system where PRIME_NUMBERS
is not enabled by default.  Resurrect CONFIG_PRIME_NUMBERS=m in
tools/testing/selftests/lib/config for the latter use case.

Fixes: 313b38a6ecb46db4 ("lib/prime_numbers: convert self-test to KUnit")
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Acked-by: Tamir Duberstein <tamird@xxxxxxxxx>
---
v2:
  - Add Acked-by,
  - Resurrect CONFIG_PRIME_NUMBERS=m in
    tools/testing/selftests/lib/config.
---
 lib/Kconfig.debug                  | 2 +-
 tools/testing/selftests/lib/config | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4060a89866626c0a..51722f5d041970aa 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -3326,7 +3326,7 @@ config GCD_KUNIT_TEST
 config PRIME_NUMBERS_KUNIT_TEST
 	tristate "Prime number generator test" if !KUNIT_ALL_TESTS
 	depends on KUNIT
-	select PRIME_NUMBERS
+	depends on PRIME_NUMBERS
 	default KUNIT_ALL_TESTS
 	help
 	  This option enables the KUnit test suite for the {is,next}_prime_number
diff --git a/tools/testing/selftests/lib/config b/tools/testing/selftests/lib/config
index 81a1f64a22e860a6..377b3699ff312933 100644
--- a/tools/testing/selftests/lib/config
+++ b/tools/testing/selftests/lib/config
@@ -1,2 +1,3 @@
 CONFIG_TEST_BITMAP=m
+CONFIG_PRIME_NUMBERS=m
 CONFIG_TEST_BITOPS=m
-- 
2.43.0