DMA-BUF Userland Memory Heaps

modulename: dma-heap.ko

configname: CONFIG_DMABUF_HEAPS

Linux Kernel Configuration
└─>Device Drivers
└─>DMABUF options
└─>DMA-BUF Userland Memory Heaps
In linux kernel since version 5.1 (release Date: 2019-05-05)  
Choose this option to enable the DMA-BUF userland memory heaps.
This options creates per heap chardevs in /dev/dma_heap/ which
allows userspace to allocate dma-bufs that can be shared
between drivers.

source code: