drm_buddy_init
err = drm_buddy_init(&mgr->mm, man->size, PAGE_SIZE);
EXPORT_SYMBOL(drm_buddy_init);
err = drm_buddy_init(&bman->mm, size, chunk_size);
int drm_buddy_init(struct drm_buddy *mm, u64 size, u64 chunk_size);
err = drm_buddy_init(&manager->mm, size, PAGE_SIZE);