RDMA/cma: Expose private data when using AF_IB

If the source or destination address is AF_IB, then do not reserve a
portion of the private data in the IB CM REQ or SIDR REQ messages for
the cma header.  Instead, all private data should be exported to the
user.  When AF_IB is used, the rdma cm does not have sufficient
information to fill in the cma header.  Additionally, this will be
necessary to support any IB connection through the rdma cm interface,
Signed-off-by: Sean Hefty <sean.hefty@intel.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>

drivers/infiniband/core/cma.c

@@ -893,9 +893,9 @@ static int cma_save_net_info(struct rdma_cm_id *id, struct rdma_cm_id *listen_id
 	return 0;
 }
 
-static inline int cma_user_data_offset(enum rdma_port_space ps)
+static inline int cma_user_data_offset(struct rdma_id_private *id_priv)
 {
-	return sizeof(struct cma_hdr);
+	return cma_family(id_priv) == AF_IB ? 0 : sizeof(struct cma_hdr);
 }
 
 static void cma_cancel_route(struct rdma_id_private *id_priv)
@@ -1265,7 +1265,7 @@ static int cma_req_handler(struct ib_cm_id *cm_id, struct ib_cm_event *ib_event)
 		return -ECONNABORTED;
 
 	memset(&event, 0, sizeof event);
-	offset = cma_user_data_offset(listen_id->id.ps);
+	offset = cma_user_data_offset(listen_id);
 	event.event = RDMA_CM_EVENT_CONNECT_REQUEST;
 	if (ib_event->event == IB_CM_SIDR_REQ_RECEIVED) {
 		conn_id = cma_new_udp_id(&listen_id->id, ib_event);
@@ -2585,7 +2585,7 @@ static int cma_format_hdr(void *hdr, struct rdma_id_private *id_priv)
 		cma_hdr->src_addr.ip4.addr = src4->sin_addr.s_addr;
 		cma_hdr->dst_addr.ip4.addr = dst4->sin_addr.s_addr;
 		cma_hdr->port = src4->sin_port;
-	} else {
+	} else if (cma_family(id_priv) == AF_INET6) {
 		struct sockaddr_in6 *src6, *dst6;
 
 		src6 = (struct sockaddr_in6 *) cma_src_addr(id_priv);
@@ -2668,24 +2668,30 @@ static int cma_resolve_ib_udp(struct rdma_id_private *id_priv,
 {
 	struct ib_cm_sidr_req_param req;
 	struct ib_cm_id	*id;
-	int ret;
+	int offset, ret;
 
-	req.private_data_len = sizeof(struct cma_hdr) +
-			       conn_param->private_data_len;
+	offset = cma_user_data_offset(id_priv);
+	req.private_data_len = offset + conn_param->private_data_len;
 	if (req.private_data_len < conn_param->private_data_len)
 		return -EINVAL;
 
+	if (req.private_data_len) {
 		req.private_data = kzalloc(req.private_data_len, GFP_ATOMIC);
 		if (!req.private_data)
 			return -ENOMEM;
+	} else {
+		req.private_data = NULL;
+	}
 
 	if (conn_param->private_data && conn_param->private_data_len)
-		memcpy((void *) req.private_data + sizeof(struct cma_hdr),
+		memcpy((void *) req.private_data + offset,
 		       conn_param->private_data, conn_param->private_data_len);
 
+	if (req.private_data) {
 		ret = cma_format_hdr((void *) req.private_data, id_priv);
 		if (ret)
 			goto out;
+	}
 
 	id = ib_create_cm_id(id_priv->id.device, cma_sidr_rep_handler,
 			     id_priv);
@@ -2720,14 +2726,18 @@ static int cma_connect_ib(struct rdma_id_private *id_priv,
 	int offset, ret;
 
 	memset(&req, 0, sizeof req);
-	offset = cma_user_data_offset(id_priv->id.ps);
+	offset = cma_user_data_offset(id_priv);
 	req.private_data_len = offset + conn_param->private_data_len;
 	if (req.private_data_len < conn_param->private_data_len)
 		return -EINVAL;
 
+	if (req.private_data_len) {
 		private_data = kzalloc(req.private_data_len, GFP_ATOMIC);
 		if (!private_data)
 			return -ENOMEM;
+	} else {
+		private_data = NULL;
+	}
 
 	if (conn_param->private_data && conn_param->private_data_len)
 		memcpy(private_data + offset, conn_param->private_data,
@@ -2741,10 +2751,12 @@ static int cma_connect_ib(struct rdma_id_private *id_priv,
 	id_priv->cm_id.ib = id;
 
 	route = &id_priv->id.route;
+	if (private_data) {
 		ret = cma_format_hdr(private_data, id_priv);
 		if (ret)
 			goto out;
 		req.private_data = private_data;
+	}
 
 	req.primary_path = &route->path_rec[0];
 	if (route->num_paths == 2)