diff --git a/drivers/gpu/drm/exynos/exynos_drm_iommu.h b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
index 72376d41c512..35d25889b476 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_iommu.h
+++ b/drivers/gpu/drm/exynos/exynos_drm_iommu.h
@@ -40,7 +40,6 @@ static inline bool is_drm_iommu_supported(struct drm_device *drm_dev)
 
 #else
 
-struct dma_iommu_mapping;
 static inline int drm_create_iommu_mapping(struct drm_device *drm_dev)
 {
 	return 0;