[PATCH V4 2/2] gpu/tests/gpu_buddy: Add KUnit test for gpu_buddy_allocated_addr_to_block

Add a new KUnit test gpu_test_buddy_addr_to_block() that validates the
gpu_buddy_allocated_addr_to_block() helper which traces a address back
to its allocated buddy block.

The test covers:
- Exact address matching returns the correct allocated block
- An unallocated address inside the manager should return NULL
- An address outside the manager should return -ENXIO

v4(MattA):
- Add test for unaligned address
v3(Sashiko):
- remove unused target_addr variable
v2(Sashiko):
- Drop the mutex and lockdep annotation; standalone KUnit tests do
  not register a driver lock.

Signed-off-by: Tejas Upadhyay <[email protected]>
---
 drivers/gpu/tests/gpu_buddy_test.c | 45 ++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/gpu/tests/gpu_buddy_test.c b/drivers/gpu/tests/gpu_buddy_test.c
index 7df5c2ae83bb..04e425eb8bdd 100644
--- a/drivers/gpu/tests/gpu_buddy_test.c
+++ b/drivers/gpu/tests/gpu_buddy_test.c
@@ -1381,6 +1381,50 @@ static void gpu_test_buddy_alloc_exceeds_max_order(struct kunit *test)
 	gpu_buddy_fini(&mm);
 }
 
+static void gpu_test_buddy_addr_to_block(struct kunit *test)
+{
+	struct gpu_buddy_block *allocated_block, *found_block;
+	LIST_HEAD(allocated_list);
+	const u64 test_size = SZ_4M + SZ_2M;
+	const u64 alloc_start = SZ_4M;
+	const u64 alloc_size = SZ_4K;
+	const u64 chunk_size = SZ_4K;
+	struct gpu_buddy mm;
+
+	KUNIT_ASSERT_FALSE_MSG(test, gpu_buddy_init(&mm, test_size, chunk_size),
+			       "buddy_init failed\n");
+
+	KUNIT_ASSERT_FALSE_MSG(test, gpu_buddy_alloc_blocks(&mm, alloc_start,
+							    alloc_start + alloc_size,
+							    alloc_size, chunk_size,
+							    &allocated_list, 0),
+			       "buddy_alloc failed\n");
+
+	allocated_block = list_first_entry(&allocated_list, struct gpu_buddy_block, link);
+	KUNIT_EXPECT_EQ(test, gpu_buddy_block_offset(allocated_block), alloc_start);
+	KUNIT_EXPECT_EQ(test, gpu_buddy_block_size(&mm, allocated_block), alloc_size);
+
+	found_block = gpu_buddy_allocated_addr_to_block(&mm, alloc_start);
+	KUNIT_EXPECT_PTR_EQ(test, found_block, allocated_block);
+
+	/* Unaligned address inside the allocated block (should resolve to the same block) */
+	found_block = gpu_buddy_allocated_addr_to_block(&mm, alloc_start + 16);
+	KUNIT_EXPECT_PTR_EQ(test, found_block, allocated_block);
+
+	/* An unallocated address inside the manager should return NULL. */
+	found_block = gpu_buddy_allocated_addr_to_block(&mm,
+							alloc_start - chunk_size);
+	KUNIT_EXPECT_NULL(test, found_block);
+
+	/* An address outside the manager should return -ENXIO. */
+	found_block = gpu_buddy_allocated_addr_to_block(&mm, test_size);
+	KUNIT_EXPECT_EQ(test, PTR_ERR(found_block), -ENXIO);
+
+	/* 3. Standard inline cleanup flow */
+	gpu_buddy_free_list(&mm, &allocated_list, 0);
+	gpu_buddy_fini(&mm);
+}
+
 static int gpu_buddy_suite_init(struct kunit_suite *suite)
 {
 	while (!random_seed)
@@ -1405,6 +1449,7 @@ static struct kunit_case gpu_buddy_tests[] = {
 	KUNIT_CASE(gpu_test_buddy_alloc_exceeds_max_order),
 	KUNIT_CASE(gpu_test_buddy_offset_aligned_allocation),
 	KUNIT_CASE(gpu_test_buddy_subtree_offset_alignment_stress),
+	KUNIT_CASE(gpu_test_buddy_addr_to_block),
 	{}
 };
 
-- 
2.52.0