sg_to_qm_sg
sg_to_qm_sg(req->src, req->cryptlen, sg_table + 1, 0);
sg_to_qm_sg(req->dst, req->cryptlen, sg_table + dst_sg_idx, 0);
sg_to_qm_sg(req->src, req->cryptlen, sg_table + 1, 0);
sg_to_qm_sg(req->dst, req->cryptlen, sg_table + dst_sg_idx, 0);
qm_sg_ptr = sg_to_qm_sg(sg, len, qm_sg_ptr, offset);
qm_sg_ptr = sg_to_qm_sg(sg, len, qm_sg_ptr, offset);