--- linux-4.9.37/drivers/base/dma-contiguous.c	2017-07-12 16:42:41.000000000 +0300
+++ linux-4.9.y/drivers/base/dma-contiguous.c	2021-06-07 13:01:33.000000000 +0300
@@ -195,6 +195,7 @@
 
 	return cma_alloc(dev_get_cma_area(dev), count, align);
 }
+EXPORT_SYMBOL(dma_alloc_from_contiguous);
 
 /**
  * dma_release_from_contiguous() - release allocated pages
@@ -211,6 +212,7 @@
 {
 	return cma_release(dev_get_cma_area(dev), pages, count);
 }
+EXPORT_SYMBOL(dma_release_from_contiguous);
 
 /*
  * Support for reserved memory regions defined in device tree