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

[Matthew Auld]

On 06/08/2026 10:46, Upadhyay, Tejas wrote:


-----Original Message-----
From: Auld, Matthew <matthew.a...@intel.com>
Sent: 06 August 2026 14:31
To: Upadhyay, Tejas <tejas.upadh...@intel.com>; intel-
x...@lists.freedesktop.org; dri-devel@lists.freedesktop.org
Cc: arunpravin.paneersel...@amd.com
Subject: Re: [PATCH V4 2/2] gpu/tests/gpu_buddy: Add KUnit test for
gpu_buddy_allocated_addr_to_block

On 06/08/2026 06:36, Tejas Upadhyay wrote:
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 <tejas.upadh...@intel.com>

Reviewed-by: Matthew Auld <matthew.a...@intel.com>

Hi Matt,

Thanks for review. Since I don’t have merge rights on drm-tip, Would you please 
help merging this series.

I think Arun normally merges these. Arun, any objections? We need this 
for an upcoming driver feature (patches on the list), so wanted to land 
this API ahead of time. I don't think this will conflict much with the 
big rework you were doing.


Tejas

---
   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),
        {}
   };