This mainly tests that find_next_iomem_res() does not miss resources.

Signed-off-by: Chia-I Wu <olvaffe@gmail.com>
---
 kernel/resource_kunit.c | 96 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)

diff --git a/kernel/resource_kunit.c b/kernel/resource_kunit.c
index 58ab9f914602b..1cbeeb44d0822 100644
--- a/kernel/resource_kunit.c
+++ b/kernel/resource_kunit.c
@@ -6,6 +6,7 @@
 #include <kunit/test.h>
 #include <linux/ioport.h>
 #include <linux/kernel.h>
+#include <linux/sizes.h>
 #include <linux/string.h>
 
 #define R0_START	0x0000
@@ -137,9 +138,104 @@ static void resource_test_intersection(struct kunit *test)
 	} while (++i < ARRAY_SIZE(results_for_intersection));
 }
 
+static int resource_walk_count(struct resource *res, void *data)
+{
+	int *count = data;
+	(*count)++;
+	return 0;
+}
+
+static void resource_test_walk_iomem_res_desc(struct kunit *test)
+{
+	struct resource root = {
+		.name = "Resource Walk Test",
+	};
+	struct resource res[8];
+	resource_size_t offset;
+	int count;
+
+	KUNIT_ASSERT_EQ(test, 0,
+			allocate_resource(&iomem_resource, &root, SZ_1M,
+				0, ~0, SZ_1M, NULL, NULL));
+
+	/* build the resource tree */
+	offset = root.start;
+	res[0] = (struct resource){
+		.start = offset,
+		.end = offset + SZ_1K - 1,
+		.name = "SYSRAM 1",
+		.flags = IORESOURCE_SYSTEM_RAM,
+	};
+	offset += SZ_1K;
+
+	res[1] = (struct resource){
+		.start = offset,
+		.end = offset + SZ_1K - 1,
+		.name = "OTHER",
+	};
+	offset += SZ_1K;
+
+	/* hole */
+	offset += SZ_1K;
+
+	res[2] = (struct resource){
+		.start = offset,
+		.end = offset + SZ_1K - 1,
+		.name = "NESTED",
+	};
+	res[3] = (struct resource){
+		.start = offset + SZ_512,
+		.end = offset + SZ_1K - 1,
+		.name = "SYSRAM 2",
+		.flags = IORESOURCE_SYSTEM_RAM,
+	};
+	offset += SZ_1K;
+
+	res[4] = (struct resource){
+		.start = offset,
+		.end = offset + SZ_1K - 1,
+		.name = "SYSRAM 3",
+		.flags = IORESOURCE_SYSTEM_RAM,
+	};
+	offset += SZ_1K;
+
+	KUNIT_EXPECT_EQ(test, 0, request_resource(&root, &res[0]));
+	KUNIT_EXPECT_EQ(test, 0, request_resource(&root, &res[1]));
+	KUNIT_EXPECT_EQ(test, 0, request_resource(&root, &res[2]));
+	KUNIT_EXPECT_EQ(test, 0, request_resource(&res[2], &res[3]));
+	KUNIT_EXPECT_EQ(test, 0, request_resource(&root, &res[4]));
+
+	/* walk the entire region */
+	count = 0;
+	walk_iomem_res_desc(IORES_DESC_NONE, IORESOURCE_SYSTEM_RAM,
+			root.start, root.end, &count, resource_walk_count);
+	KUNIT_EXPECT_EQ(test, count, 3);
+
+	/* walk the region requested by res[1] */
+	count = 0;
+	walk_iomem_res_desc(IORES_DESC_NONE, IORESOURCE_SYSTEM_RAM,
+			res[1].start, res[1].end, &count, resource_walk_count);
+	KUNIT_EXPECT_EQ(test, count, 0);
+
+	/* walk the region requested by res[2] */
+	count = 0;
+	walk_iomem_res_desc(IORES_DESC_NONE, IORESOURCE_SYSTEM_RAM,
+			res[2].start, res[2].end, &count, resource_walk_count);
+	KUNIT_EXPECT_EQ(test, count, 1);
+
+	/* walk the region requested by res[4] */
+	count = 0;
+	walk_iomem_res_desc(IORES_DESC_NONE, IORESOURCE_SYSTEM_RAM,
+			res[4].start, res[4].end, &count, resource_walk_count);
+	KUNIT_EXPECT_EQ(test, count, 1);
+
+	release_resource(&root);
+}
+
 static struct kunit_case resource_test_cases[] = {
 	KUNIT_CASE(resource_test_union),
 	KUNIT_CASE(resource_test_intersection),
+	KUNIT_CASE(resource_test_walk_iomem_res_desc),
 	{}
 };
 
-- 
2.45.1.288.g0e0cd299f1-goog

On Tue, Jun 04, 2024 at 02:31:46PM -0700, Chia-I Wu wrote:
> This mainly tests that find_next_iomem_res() does not miss resources.

In the Subject:  walk_iomem_res_desc()

> Signed-off-by: Chia-I Wu <olvaffe@gmail.com>

...

> +	res[2] = (struct resource){
> +		.start = offset,
> +		.end = offset + SZ_1K - 1,
> +		.name = "NESTED",
> +	};

We have respective macros. Use them.

-- 
With Best Regards,
Andy Shevchenko

On Wed, Jun 05, 2024 at 12:38:27AM +0300, Andy Shevchenko wrote:
> On Tue, Jun 04, 2024 at 02:31:46PM -0700, Chia-I Wu wrote:

...

> > +	res[2] = (struct resource){
> > +		.start = offset,
> > +		.end = offset + SZ_1K - 1,
> > +		.name = "NESTED",
> > +	};
> 
> We have respective macros. Use them.

And use explicitly hardocded start in all of them instead of coding += for
offset variable. For the test cases is better when data is hardcoded, esp.
when it's an expected result (just to mention, here it seems an input data).

-- 
With Best Regards,
Andy Shevchenko