RDS: Remove struct rds_rdma_op

A big changeset, but it's all pretty dumb.

struct rds_rdma_op was already embedded in struct rm_rdma_op.
Remove rds_rdma_op and put its members in rm_rdma_op. Rename
members with "op_" prefix instead of "r_", for consistency.

Of course this breaks a lot, so fixup the code accordingly.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
diff --git a/net/rds/message.c b/net/rds/message.c
index b53306c..bca7eda 100644
--- a/net/rds/message.c
+++ b/net/rds/message.c
@@ -69,10 +69,10 @@
 	}
 	rm->data.m_nents = 0;
 
-	if (rm->rdma.m_rdma_op.r_active)
-		rds_rdma_free_op(&rm->rdma.m_rdma_op);
-	if (rm->rdma.m_rdma_mr)
-		rds_mr_put(rm->rdma.m_rdma_mr);
+	if (rm->rdma.op_active)
+		rds_rdma_free_op(&rm->rdma);
+	if (rm->rdma.op_rdma_mr)
+		rds_mr_put(rm->rdma.op_rdma_mr);
 
 	if (rm->atomic.op_active)
 		rds_atomic_free_op(&rm->atomic);