drm/buddy: Add a testcase to verify the multiroot fini

- Added a testcase to verify the multiroot force merge fini.
- Added a new field in_use to track the mm freed status.

v2:(Matthew)
  - Add kunit_fail_current_test() when WARN_ON is true.

Signed-off-by: Arunpravin Paneer Selvam <Arunpravin.PaneerSelvam@amd.com>
Signed-off-by: Lin.Cao <lincao12@amd.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241226070116.309290-2-Arunpravin.PaneerSelvam@amd.com

2 files changed, 25 insertions, 10 deletions

diff --git a/drivers/gpu/drm/drm_buddy.c b/drivers/gpu/drm/drm_buddy.c
index ca42e6081d27..241c855f891f 100644
--- a/drivers/gpu/drm/drm_buddy.c
+++ b/drivers/gpu/drm/drm_buddy.c
@@ -3,6 +3,8 @@
  * Copyright © 2021 Intel Corporation
  */
 
+#include <kunit/test-bug.h>
+
 #include <linux/kmemleak.h>
 #include <linux/module.h>
 #include <linux/sizes.h>
@@ -335,7 +337,9 @@ void drm_buddy_fini(struct drm_buddy *mm)
 		start = drm_buddy_block_offset(mm->roots[i]);
 		__force_merge(mm, start, start + size, order);
 
-		WARN_ON(!drm_buddy_block_is_free(mm->roots[i]));
+		if (WARN_ON(!drm_buddy_block_is_free(mm->roots[i])))
+			kunit_fail_current_test("buddy_fini() root");
+
 		drm_block_free(mm, mm->roots[i]);
 
 		root_size = mm->chunk_size << order;
diff --git a/drivers/gpu/drm/tests/drm_buddy_test.c b/drivers/gpu/drm/tests/drm_buddy_test.c
index 9662c949d0e3..4b5818f9f2a9 100644
--- a/drivers/gpu/drm/tests/drm_buddy_test.c
+++ b/drivers/gpu/drm/tests/drm_buddy_test.c
@@ -385,17 +385,28 @@ static void drm_test_buddy_alloc_clear(struct kunit *test)
 	drm_buddy_fini(&mm);
 
 	/*
-	 * Create a new mm with a non power-of-two size. Allocate a random size, free as
-	 * cleared and then call fini. This will ensure the multi-root force merge during
-	 * fini.
+	 * Create a new mm with a non power-of-two size. Allocate a random size from each
+	 * root, free as cleared and then call fini. This will ensure the multi-root
+	 * force merge during fini.
 	 */
-	mm_size = 12 * SZ_4K;
-	size = max(round_up(prandom_u32_state(&prng) % mm_size, ps), ps);
+	mm_size = (SZ_4K << max_order) + (SZ_4K << (max_order - 2));
+
 	KUNIT_EXPECT_FALSE(test, drm_buddy_init(&mm, mm_size, ps));
-	KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, mm_size,
-							    size, ps, &allocated,
-							    DRM_BUDDY_TOPDOWN_ALLOCATION),
-				"buddy_alloc hit an error size=%u\n", size);
+	KUNIT_EXPECT_EQ(test, mm.max_order, max_order);
+	KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, SZ_4K << max_order,
+							    4 * ps, ps, &allocated,
+							    DRM_BUDDY_RANGE_ALLOCATION),
+				"buddy_alloc hit an error size=%lu\n", 4 * ps);
+	drm_buddy_free_list(&mm, &allocated, DRM_BUDDY_CLEARED);
+	KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_alloc_blocks(&mm, 0, SZ_4K << max_order,
+							    2 * ps, ps, &allocated,
+							    DRM_BUDDY_CLEAR_ALLOCATION),
+				"buddy_alloc hit an error size=%lu\n", 2 * ps);
+	drm_buddy_free_list(&mm, &allocated, DRM_BUDDY_CLEARED);
+	KUNIT_ASSERT_FALSE_MSG(test, drm_buddy_alloc_blocks(&mm, SZ_4K << max_order, mm_size,
+							    ps, ps, &allocated,
+							    DRM_BUDDY_RANGE_ALLOCATION),
+				"buddy_alloc hit an error size=%lu\n", ps);
 	drm_buddy_free_list(&mm, &allocated, DRM_BUDDY_CLEARED);
 	drm_buddy_fini(&mm);
 }