[PATCH] resource, kunit: stop selecting GET_FREE_REGION

[Karl Mehltretter]

RESOURCE_KUNIT_TEST selects GET_FREE_REGION even when no other option
needs it. Remove the selection to follow the dependency rule in
Documentation/dev-tools/kunit/style.rst.

Skip resource_test_region_intersects() when GET_FREE_REGION is disabled.
GET_FREE_REGION has no prompt, so configurations without a production
consumer cannot enable it. Most configurations will therefore skip this
case; this is intentional. The union and intersection tests remain
available.

Since kunit_skip() does not return, the compiler drops the reference to
the unavailable alloc_free_mem_region(), as in the CONFIG_OF_ADDRESS
check in drivers/of/of_test.c.

Fixes: 99185c10d5d9 ("resource, kunit: add test case for region_intersects()")
Assisted-by: LLM
Signed-off-by: Karl Mehltretter <kmehlt...@gmail.com>
---
Validation:
- Clang 22 and GCC 13 ARM builds pass with RESOURCE_KUNIT_TEST=y and =m
while GET_FREE_REGION=n. The built-in vmlinux images have no
alloc_free_mem_region symbol, and the modules have no undefined
reference to it.
- Clang 22 x86_64 builds and QEMU 11.0.2 runs pass. GET_FREE_REGION=n
reports two passes and resource_test_region_intersects as SKIP;
DEVICE_PRIVATE=y enables GET_FREE_REGION and reports three passes.

kernel/resource_kunit.c | 3 +++
lib/Kconfig.debug | 1 -
2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/resource_kunit.c b/kernel/resource_kunit.c
index 42785796f1db..9eeb2b1a85c0 100644
--- a/kernel/resource_kunit.c
+++ b/kernel/resource_kunit.c
@@ -225,6 +225,9 @@ static void resource_test_region_intersects(struct kunit *test)
struct resource *parent;
resource_size_t start;

+ if (!IS_ENABLED(CONFIG_GET_FREE_REGION))
+ kunit_skip(test, "CONFIG_GET_FREE_REGION is disabled");
+
/* Find an iomem_resource hole to hold test resources */
parent = alloc_free_mem_region(&iomem_resource, RES_TEST_TOTAL_SIZE, SZ_1M,
"test resources");
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 134b15a44625..e7c5d5b5870f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2776,7 +2776,6 @@ config RESOURCE_KUNIT_TEST
tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
depends on KUNIT
default KUNIT_ALL_TESTS
- select GET_FREE_REGION
help
This builds the resource API unit test.
Tests the logic of API provided by resource.c and ioport.h.

base-commit: aa98230e410f0ed212b6788c46b1e4d49e0ff7ca
--
2.39.5 (Apple Git-154)

[Bradley Morgan]

On 26 September 2026 01:26:51 BST, Karl Mehltretter

Interesting.

Reviewed-by: Bradley Morgan <br...@mainlining.org>

Tested on Power10 (PowerPC), in courtesy of osuosl:

Tested-by: Bradley Morgan <br...@mainlining.org> # Power10

>+
> /* Find an iomem_resource hole to hold test resources */
> parent = alloc_free_mem_region(&iomem_resource, RES_TEST_TOTAL_SIZE, SZ_1M,
> "test resources");
>diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
>index 134b15a44625..e7c5d5b5870f 100644
>--- a/lib/Kconfig.debug
>+++ b/lib/Kconfig.debug
>@@ -2776,7 +2776,6 @@ config RESOURCE_KUNIT_TEST
> tristate "KUnit test for resource API" if !KUNIT_ALL_TESTS
> depends on KUNIT
> default KUNIT_ALL_TESTS
>- select GET_FREE_REGION
> help
> This builds the resource API unit test.
> Tests the logic of API provided by resource.c and ioport.h.
>
>base-commit: aa98230e410f0ed212b6788c46b1e4d49e0ff7ca
>

--- Thanks!
"I'm not a very positive person" - Linus torvalds