dma_memory_desc
struct dma_memory_desc ioctl_sge[MPI3MR_NUM_IOCTL_SGE];
struct dma_memory_desc ioctl_chain_sge;
struct dma_memory_desc ioctl_resp_sge;
struct dma_memory_desc *dma_desc;
struct dma_memory_desc *mem_desc;
struct dma_memory_desc *mem_desc;
struct dma_memory_desc mem_desc;
memset(&mem_desc, 0, sizeof(struct dma_memory_desc));