diff --git a/drivers/gpu/drm/i915/selftests/mock_engine.c b/drivers/gpu/drm/i915/selftests/mock_engine.c
index 0aafa8a105b8f08165c715740434b58ffd00b10e..55c0e2c15782f76dfeb3f9734593e6889e5937ca 100644
--- a/drivers/gpu/drm/i915/selftests/mock_engine.c
+++ b/drivers/gpu/drm/i915/selftests/mock_engine.c
@@ -124,9 +124,11 @@ static void mock_submit_request(struct drm_i915_gem_request *request)
 
 static struct intel_ring *mock_ring(struct intel_engine_cs *engine)
 {
-	const unsigned long sz = roundup_pow_of_two(sizeof(struct intel_ring));
+	const unsigned long sz = PAGE_SIZE / 2;
 	struct intel_ring *ring;
 
+	BUILD_BUG_ON(MIN_SPACE_FOR_ADD_REQUEST > sz);
+
 	ring = kzalloc(sizeof(*ring) + sz, GFP_KERNEL);
 	if (!ring)
 		return NULL;