Unmaps and decreases usecount of the buffer;might deallocate the scatterlist associated. is a wrapper for unmap_dma_buf of dma_buf_ops.
void dma_buf_unmap_attachment(struct dma_buf_attachment * attach, struct sg_table * sg_table, enum dma_data_direction direction);
attach
[in] attachment to unmap buffer from
sg_table
[in] scatterlist info of the buffer to unmap
direction
[in] direction of DMA transfer