siw_mem_id2obj
new = siw_mem_id2obj(sdev, sge->lkey >> 8);
struct siw_mem *mem = siw_mem_id2obj(sdev, stag >> 8);
struct siw_mem *siw_mem_id2obj(struct siw_device *sdev, int stag_index);
rx_mem(frx) = siw_mem_id2obj(qp->sdev, srx->ddp_stag >> 8);
mem = siw_mem_id2obj(sdev, sqe->rkey >> 8);