[PATCH] drm/mm: Reduce stack frame usage in __igt_reserve

[Maíra Canal]

The struct drm_mm is being allocated on the stack, which is causing the
following -Wframe-larger-than warning on ARM:

../drivers/gpu/drm/tests/drm_mm_test.c:344:12: error: stack frame size
(1064) exceeds limit (1024) in '__igt_reserve' [-Werror,-Wframe-larger-than]

static int __igt_reserve(struct kunit *test, unsigned int count, u64 size)
           ^
1 error generated.

So, fix this warning by dynamically allocating the struct drm_mm.

Fixes: fc8d29e298cf ("drm: selftest: convert drm_mm selftest to KUnit")
Reported-by: kernel test robot <lkp at intel.com>
Signed-off-by: Maíra Canal <mairacanal at riseup.net>
---
 drivers/gpu/drm/tests/drm_mm_test.c | 33 ++++++++++++++++-------------
 1 file changed, 18 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/tests/drm_mm_test.c b/drivers/gpu/drm/tests/drm_mm_test.c
index 1e2c1aa524bd..fbd8dcbc12ee 100644
--- a/drivers/gpu/drm/tests/drm_mm_test.c
+++ b/drivers/gpu/drm/tests/drm_mm_test.c
@@ -344,7 +344,7 @@ static bool check_reserve_boundaries(struct kunit *test, struct drm_mm *mm,
 static int __igt_reserve(struct kunit *test, unsigned int count, u64 size)
 {
 	DRM_RND_STATE(prng, random_seed);
-	struct drm_mm mm;
+	struct drm_mm *mm;
 	struct drm_mm_node tmp, *nodes, *node, *next;
 	unsigned int *order, n, m, o = 0;
 	int ret, err;
@@ -366,17 +366,20 @@ static int __igt_reserve(struct kunit *test, unsigned int count, u64 size)
 	nodes = vzalloc(array_size(count, sizeof(*nodes)));
 	KUNIT_ASSERT_TRUE(test, nodes);
 
+	mm = kunit_kzalloc(test, sizeof(struct drm_mm), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, mm);
+
 	ret = -EINVAL;
-	drm_mm_init(&mm, 0, count * size);
+	drm_mm_init(mm, 0, count * size);
 
-	if (!check_reserve_boundaries(test, &mm, count, size))
+	if (!check_reserve_boundaries(test, mm, count, size))
 		goto out;
 
 	for (n = 0; n < count; n++) {
 		nodes[n].start = order[n] * size;
 		nodes[n].size = size;
 
-		err = drm_mm_reserve_node(&mm, &nodes[n]);
+		err = drm_mm_reserve_node(mm, &nodes[n]);
 		if (err) {
 			KUNIT_FAIL(test, "reserve failed, step %d, start %llu\n",
 				   n, nodes[n].start);
@@ -390,23 +393,23 @@ static int __igt_reserve(struct kunit *test, unsigned int count, u64 size)
 			goto out;
 		}
 
-		if (!expect_reserve_fail(test, &mm, &nodes[n]))
+		if (!expect_reserve_fail(test, mm, &nodes[n]))
 			goto out;
 	}
 
 	/* After random insertion the nodes should be in order */
-	if (!assert_continuous(test, &mm, size))
+	if (!assert_continuous(test, mm, size))
 		goto out;
 
 	/* Repeated use should then fail */
 	drm_random_reorder(order, count, &prng);
 	for (n = 0; n < count; n++) {
-		if (!expect_reserve_fail(test, &mm, set_node(&tmp, order[n] * size, 1)))
+		if (!expect_reserve_fail(test, mm, set_node(&tmp, order[n] * size, 1)))
 			goto out;
 
 		/* Remove and reinsert should work */
 		drm_mm_remove_node(&nodes[order[n]]);
-		err = drm_mm_reserve_node(&mm, &nodes[order[n]]);
+		err = drm_mm_reserve_node(mm, &nodes[order[n]]);
 		if (err) {
 			KUNIT_FAIL(test, "reserve failed, step %d, start %llu\n",
 				   n, nodes[n].start);
@@ -415,16 +418,16 @@ static int __igt_reserve(struct kunit *test, unsigned int count, u64 size)
 		}
 	}
 
-	if (!assert_continuous(test, &mm, size))
+	if (!assert_continuous(test, mm, size))
 		goto out;
 
 	/* Overlapping use should then fail */
 	for (n = 0; n < count; n++) {
-		if (!expect_reserve_fail(test, &mm, set_node(&tmp, 0, size * count)))
+		if (!expect_reserve_fail(test, mm, set_node(&tmp, 0, size * count)))
 			goto out;
 	}
 	for (n = 0; n < count; n++) {
-		if (!expect_reserve_fail(test, &mm, set_node(&tmp, size * n, size * (count - n))))
+		if (!expect_reserve_fail(test, mm, set_node(&tmp, size * n, size * (count - n))))
 			goto out;
 	}
 
@@ -437,7 +440,7 @@ static int __igt_reserve(struct kunit *test, unsigned int count, u64 size)
 
 		for (m = 0; m < n; m++) {
 			node = &nodes[order[(o + m) % count]];
-			err = drm_mm_reserve_node(&mm, node);
+			err = drm_mm_reserve_node(mm, node);
 			if (err) {
 				KUNIT_FAIL(test, "reserve failed, step %d/%d, start %llu\n",
 					   m, n, node->start);
@@ -448,15 +451,15 @@ static int __igt_reserve(struct kunit *test, unsigned int count, u64 size)
 
 		o += n;
 
-		if (!assert_continuous(test, &mm, size))
+		if (!assert_continuous(test, mm, size))
 			goto out;
 	}
 
 	ret = 0;
 out:
-	drm_mm_for_each_node_safe(node, next, &mm)
+	drm_mm_for_each_node_safe(node, next, mm)
 		drm_mm_remove_node(node);
-	drm_mm_takedown(&mm);
+	drm_mm_takedown(mm);
 	vfree(nodes);
 	kfree(order);
 err:
-- 
2.37.2