참고 https://forums.xilinx.com/xlnx/attachments/xlnx/ELINUX/10693/1/Linux%20DMA%20from%20User%20Space-public.pdf https://github.com/ikwzm/udmabuf/blob/master/LICENSE http://netaz.blogspot.kr/2015/11/dma-buffer-sharing.html https://github.com/mstuehn/dma_proxy/blob/master/dma_proxy_test.c http://netaz.blogspot.kr/2015/11/dma-buffer-sharing.html