RDS: break out rdma and data ops into nested structs in rds_message

Clearly separate rdma-related variables in rm from data-related ones.
This is in anticipation of adding atomic support.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/rdma.c b/net/rds/rdma.c
index dee698b..24274bb 100644
--- a/net/rds/rdma.c
+++ b/net/rds/rdma.c
@@ -643,14 +643,14 @@
 	struct rds_rdma_op *op;
 
 	if (cmsg->cmsg_len < CMSG_LEN(sizeof(struct rds_rdma_args)) ||
-	    rm->m_rdma_op)
+	    rm->rdma.m_rdma_op)
 		return -EINVAL;
 
 	op = rds_rdma_prepare(rs, CMSG_DATA(cmsg));
 	if (IS_ERR(op))
 		return PTR_ERR(op);
 	rds_stats_inc(s_send_rdma);
-	rm->m_rdma_op = op;
+	rm->rdma.m_rdma_op = op;
 	return 0;
 }
 
@@ -679,6 +679,7 @@
 	 */
 	r_key = rds_rdma_cookie_key(rm->m_rdma_cookie);
 
+
 	spin_lock_irqsave(&rs->rs_rdma_lock, flags);
 	mr = rds_mr_tree_walk(&rs->rs_rdma_keys, r_key, NULL);
 	if (!mr)
@@ -689,7 +690,7 @@
 
 	if (mr) {
 		mr->r_trans->sync_mr(mr->r_trans_private, DMA_TO_DEVICE);
-		rm->m_rdma_mr = mr;
+		rm->rdma.m_rdma_mr = mr;
 	}
 	return err;
 }
@@ -707,5 +708,5 @@
 	    rm->m_rdma_cookie != 0)
 		return -EINVAL;
 
-	return __rds_rdma_map(rs, CMSG_DATA(cmsg), &rm->m_rdma_cookie, &rm->m_rdma_mr);
+	return __rds_rdma_map(rs, CMSG_DATA(cmsg), &rm->m_rdma_cookie, &rm->rdma.m_rdma_mr);
 }