RDS: Common RDMA transport code

Although most of IB and iWARP are separated from each other,
there is some common code required to handle their shared
CM listen port. This code listens for CM events and then
dispatches the event to the appropriate transport, either
IB or iWARP.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/rds/rdma_transport.c

+/*
+ * Copyright (c) 2009 Oracle.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#include <rdma/rdma_cm.h>
+
+#include "rdma_transport.h"
+
+static struct rdma_cm_id *rds_iw_listen_id;
+
+int rds_rdma_cm_event_handler(struct rdma_cm_id *cm_id,
+			      struct rdma_cm_event *event)
+{
+	/* this can be null in the listening path */
+	struct rds_connection *conn = cm_id->context;
+	struct rds_transport *trans;
+	int ret = 0;
+
+	rdsdebug("conn %p id %p handling event %u\n", conn, cm_id,
+		 event->event);
+
+	if (cm_id->device->node_type == RDMA_NODE_RNIC)
+		trans = &rds_iw_transport;
+	else
+		trans = &rds_ib_transport;
+
+	/* Prevent shutdown from tearing down the connection
+	 * while we're executing. */
+	if (conn) {
+		mutex_lock(&conn->c_cm_lock);
+
+		/* If the connection is being shut down, bail out
+		 * right away. We return 0 so cm_id doesn't get
+		 * destroyed prematurely */
+		if (rds_conn_state(conn) == RDS_CONN_DISCONNECTING) {
+			/* Reject incoming connections while we're tearing
+			 * down an existing one. */
+			if (event->event == RDMA_CM_EVENT_CONNECT_REQUEST)
+				ret = 1;
+			goto out;
+		}
+	}
+
+	switch (event->event) {
+	case RDMA_CM_EVENT_CONNECT_REQUEST:
+		ret = trans->cm_handle_connect(cm_id, event);
+		break;
+
+	case RDMA_CM_EVENT_ADDR_RESOLVED:
+		/* XXX do we need to clean up if this fails? */
+		ret = rdma_resolve_route(cm_id,
+					 RDS_RDMA_RESOLVE_TIMEOUT_MS);
+		break;
+
+	case RDMA_CM_EVENT_ROUTE_RESOLVED:
+		/* XXX worry about racing with listen acceptance */
+		ret = trans->cm_initiate_connect(cm_id);
+		break;
+
+	case RDMA_CM_EVENT_ESTABLISHED:
+		trans->cm_connect_complete(conn, event);
+		break;
+
+	case RDMA_CM_EVENT_ADDR_ERROR:
+	case RDMA_CM_EVENT_ROUTE_ERROR:
+	case RDMA_CM_EVENT_CONNECT_ERROR:
+	case RDMA_CM_EVENT_UNREACHABLE:
+	case RDMA_CM_EVENT_REJECTED:
+	case RDMA_CM_EVENT_DEVICE_REMOVAL:
+	case RDMA_CM_EVENT_ADDR_CHANGE:
+		if (conn)
+			rds_conn_drop(conn);
+		break;
+
+	case RDMA_CM_EVENT_DISCONNECTED:
+		printk(KERN_WARNING "RDS/IW: DISCONNECT event - dropping connection "
+			"%pI4->%pI4\n", &conn->c_laddr,
+			 &conn->c_faddr);
+		rds_conn_drop(conn);
+		break;
+
+	default:
+		/* things like device disconnect? */
+		printk(KERN_ERR "unknown event %u\n", event->event);
+		BUG();
+		break;
+	}
+
+out:
+	if (conn)
+		mutex_unlock(&conn->c_cm_lock);
+
+	rdsdebug("id %p event %u handling ret %d\n", cm_id, event->event, ret);
+
+	return ret;
+}
+
+static int __init rds_rdma_listen_init(void)
+{
+	struct sockaddr_in sin;
+	struct rdma_cm_id *cm_id;
+	int ret;
+
+	cm_id = rdma_create_id(rds_rdma_cm_event_handler, NULL, RDMA_PS_TCP);
+	if (IS_ERR(cm_id)) {
+		ret = PTR_ERR(cm_id);
+		printk(KERN_ERR "RDS/IW: failed to setup listener, "
+		       "rdma_create_id() returned %d\n", ret);
+		goto out;
+	}
+
+	sin.sin_family = PF_INET,
+	sin.sin_addr.s_addr = (__force u32)htonl(INADDR_ANY);
+	sin.sin_port = (__force u16)htons(RDS_PORT);
+
+	/*
+	 * XXX I bet this binds the cm_id to a device.  If we want to support
+	 * fail-over we'll have to take this into consideration.
+	 */
+	ret = rdma_bind_addr(cm_id, (struct sockaddr *)&sin);
+	if (ret) {
+		printk(KERN_ERR "RDS/IW: failed to setup listener, "
+		       "rdma_bind_addr() returned %d\n", ret);
+		goto out;
+	}
+
+	ret = rdma_listen(cm_id, 128);
+	if (ret) {
+		printk(KERN_ERR "RDS/IW: failed to setup listener, "
+		       "rdma_listen() returned %d\n", ret);
+		goto out;
+	}
+
+	rdsdebug("cm %p listening on port %u\n", cm_id, RDS_PORT);
+
+	rds_iw_listen_id = cm_id;
+	cm_id = NULL;
+out:
+	if (cm_id)
+		rdma_destroy_id(cm_id);
+	return ret;
+}
+
+static void rds_rdma_listen_stop(void)
+{
+	if (rds_iw_listen_id) {
+		rdsdebug("cm %p\n", rds_iw_listen_id);
+		rdma_destroy_id(rds_iw_listen_id);
+		rds_iw_listen_id = NULL;
+	}
+}
+
+int __init rds_rdma_init(void)
+{
+	int ret;
+
+	ret = rds_rdma_listen_init();
+	if (ret)
+		goto out;
+
+	ret = rds_iw_init();
+	if (ret)
+		goto err_iw_init;
+
+	ret = rds_ib_init();
+	if (ret)
+		goto err_ib_init;
+
+	goto out;
+
+err_ib_init:
+	rds_iw_exit();
+err_iw_init:
+	rds_rdma_listen_stop();
+out:
+	return ret;
+}
+
+void rds_rdma_exit(void)
+{
+	/* stop listening first to ensure no new connections are attempted */
+	rds_rdma_listen_stop();
+	rds_ib_exit();
+	rds_iw_exit();
+}
+

net/rds/rdma_transport.h

+#ifndef _RDMA_TRANSPORT_H
+#define _RDMA_TRANSPORT_H
+
+#include <rdma/ib_verbs.h>
+#include <rdma/rdma_cm.h>
+#include "rds.h"
+
+#define RDS_RDMA_RESOLVE_TIMEOUT_MS     5000
+
+int rds_rdma_conn_connect(struct rds_connection *conn);
+int rds_rdma_cm_event_handler(struct rdma_cm_id *cm_id,
+			      struct rdma_cm_event *event);
+
+/* from rdma_transport.c */
+int rds_rdma_init(void);
+void rds_rdma_exit(void);
+
+/* from ib.c */
+extern struct rds_transport rds_ib_transport;
+int rds_ib_init(void);
+void rds_ib_exit(void);
+
+/* from iw.c */
+extern struct rds_transport rds_iw_transport;
+int rds_iw_init(void);
+void rds_iw_exit(void);
+
+#endif