/*
   * Copyright (c) 2006 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 <linux/kernel.h>
  #include <linux/in.h>
  #include <linux/slab.h>
  #include <linux/vmalloc.h>
  #include <linux/ratelimit.h>
  
  #include "rds.h"
  #include "ib.h"
  
  static char *rds_ib_event_type_strings[] = {
  #define RDS_IB_EVENT_STRING(foo) \
  		[IB_EVENT_##foo] = __stringify(IB_EVENT_##foo)
  	RDS_IB_EVENT_STRING(CQ_ERR),
  	RDS_IB_EVENT_STRING(QP_FATAL),
  	RDS_IB_EVENT_STRING(QP_REQ_ERR),
  	RDS_IB_EVENT_STRING(QP_ACCESS_ERR),
  	RDS_IB_EVENT_STRING(COMM_EST),
  	RDS_IB_EVENT_STRING(SQ_DRAINED),
  	RDS_IB_EVENT_STRING(PATH_MIG),
  	RDS_IB_EVENT_STRING(PATH_MIG_ERR),
  	RDS_IB_EVENT_STRING(DEVICE_FATAL),
  	RDS_IB_EVENT_STRING(PORT_ACTIVE),
  	RDS_IB_EVENT_STRING(PORT_ERR),
  	RDS_IB_EVENT_STRING(LID_CHANGE),
  	RDS_IB_EVENT_STRING(PKEY_CHANGE),
  	RDS_IB_EVENT_STRING(SM_CHANGE),
  	RDS_IB_EVENT_STRING(SRQ_ERR),
  	RDS_IB_EVENT_STRING(SRQ_LIMIT_REACHED),
  	RDS_IB_EVENT_STRING(QP_LAST_WQE_REACHED),
  	RDS_IB_EVENT_STRING(CLIENT_REREGISTER),
  #undef RDS_IB_EVENT_STRING
  };
  
  static char *rds_ib_event_str(enum ib_event_type type)
  {
  	return rds_str_array(rds_ib_event_type_strings,
  			     ARRAY_SIZE(rds_ib_event_type_strings), type);
  };
  
  /*
   * Set the selected protocol version
   */
  static void rds_ib_set_protocol(struct rds_connection *conn, unsigned int version)
  {
  	conn->c_version = version;
  }
  
  /*
   * Set up flow control
   */
  static void rds_ib_set_flow_control(struct rds_connection *conn, u32 credits)
  {
  	struct rds_ib_connection *ic = conn->c_transport_data;
  
  	if (rds_ib_sysctl_flow_control && credits != 0) {
  		/* We're doing flow control */
  		ic->i_flowctl = 1;
  		rds_ib_send_add_credits(conn, credits);
  	} else {
  		ic->i_flowctl = 0;
  	}
  }
  
  /*
   * Tune RNR behavior. Without flow control, we use a rather
   * low timeout, but not the absolute minimum - this should
   * be tunable.
   *
   * We already set the RNR retry count to 7 (which is the
   * smallest infinite number :-) above.
   * If flow control is off, we want to change this back to 0
   * so that we learn quickly when our credit accounting is
   * buggy.
   *
   * Caller passes in a qp_attr pointer - don't waste stack spacv
   * by allocation this twice.
   */
  static void
  rds_ib_tune_rnr(struct rds_ib_connection *ic, struct ib_qp_attr *attr)
  {
  	int ret;
  
  	attr->min_rnr_timer = IB_RNR_TIMER_000_32;
  	ret = ib_modify_qp(ic->i_cm_id->qp, attr, IB_QP_MIN_RNR_TIMER);
  	if (ret)
  		printk(KERN_NOTICE "ib_modify_qp(IB_QP_MIN_RNR_TIMER): err=%d
  ", -ret);
  }
  
  /*
   * Connection established.
   * We get here for both outgoing and incoming connection.
   */
  void rds_ib_cm_connect_complete(struct rds_connection *conn, struct rdma_cm_event *event)
  {
  	const struct rds_ib_connect_private *dp = NULL;
  	struct rds_ib_connection *ic = conn->c_transport_data;
  	struct ib_qp_attr qp_attr;
  	int err;
  
  	if (event->param.conn.private_data_len >= sizeof(*dp)) {
  		dp = event->param.conn.private_data;
  
  		/* make sure it isn't empty data */
  		if (dp->dp_protocol_major) {
  			rds_ib_set_protocol(conn,
  				RDS_PROTOCOL(dp->dp_protocol_major,
  				dp->dp_protocol_minor));
  			rds_ib_set_flow_control(conn, be32_to_cpu(dp->dp_credit));
  		}
  	}
  
  	if (conn->c_version < RDS_PROTOCOL(3,1)) {
  		printk(KERN_NOTICE "RDS/IB: Connection to %pI4 version %u.%u failed,"
  		       " no longer supported
  ",
  		       &conn->c_faddr,
  		       RDS_PROTOCOL_MAJOR(conn->c_version),
  		       RDS_PROTOCOL_MINOR(conn->c_version));
  		rds_conn_destroy(conn);
  		return;
  	} else {
  		printk(KERN_NOTICE "RDS/IB: connected to %pI4 version %u.%u%s
  ",
  		       &conn->c_faddr,
  		       RDS_PROTOCOL_MAJOR(conn->c_version),
  		       RDS_PROTOCOL_MINOR(conn->c_version),
  		       ic->i_flowctl ? ", flow control" : "");
  	}
  
  	/*
  	 * Init rings and fill recv. this needs to wait until protocol negotiation
  	 * is complete, since ring layout is different from 3.0 to 3.1.
  	 */
  	rds_ib_send_init_ring(ic);
  	rds_ib_recv_init_ring(ic);
  	/* Post receive buffers - as a side effect, this will update
  	 * the posted credit count. */
  	rds_ib_recv_refill(conn, 1);
  
  	/* Tune RNR behavior */
  	rds_ib_tune_rnr(ic, &qp_attr);
  
  	qp_attr.qp_state = IB_QPS_RTS;
  	err = ib_modify_qp(ic->i_cm_id->qp, &qp_attr, IB_QP_STATE);
  	if (err)
  		printk(KERN_NOTICE "ib_modify_qp(IB_QP_STATE, RTS): err=%d
  ", err);
  
  	/* update ib_device with this local ipaddr */
  	err = rds_ib_update_ipaddr(ic->rds_ibdev, conn->c_laddr);
  	if (err)
  		printk(KERN_ERR "rds_ib_update_ipaddr failed (%d)
  ",
  			err);
  
  	/* If the peer gave us the last packet it saw, process this as if
  	 * we had received a regular ACK. */
  	if (dp && dp->dp_ack_seq)
  		rds_send_drop_acked(conn, be64_to_cpu(dp->dp_ack_seq), NULL);
  
  	rds_connect_complete(conn);
  }
  
  static void rds_ib_cm_fill_conn_param(struct rds_connection *conn,
  			struct rdma_conn_param *conn_param,
  			struct rds_ib_connect_private *dp,
  			u32 protocol_version,
  			u32 max_responder_resources,
  			u32 max_initiator_depth)
  {
  	struct rds_ib_connection *ic = conn->c_transport_data;
  	struct rds_ib_device *rds_ibdev = ic->rds_ibdev;
  
  	memset(conn_param, 0, sizeof(struct rdma_conn_param));
  
  	conn_param->responder_resources =
  		min_t(u32, rds_ibdev->max_responder_resources, max_responder_resources);
  	conn_param->initiator_depth =
  		min_t(u32, rds_ibdev->max_initiator_depth, max_initiator_depth);
  	conn_param->retry_count = min_t(unsigned int, rds_ib_retry_count, 7);
  	conn_param->rnr_retry_count = 7;
  
  	if (dp) {
  		memset(dp, 0, sizeof(*dp));
  		dp->dp_saddr = conn->c_laddr;
  		dp->dp_daddr = conn->c_faddr;
  		dp->dp_protocol_major = RDS_PROTOCOL_MAJOR(protocol_version);
  		dp->dp_protocol_minor = RDS_PROTOCOL_MINOR(protocol_version);
  		dp->dp_protocol_minor_mask = cpu_to_be16(RDS_IB_SUPPORTED_PROTOCOLS);
  		dp->dp_ack_seq = rds_ib_piggyb_ack(ic);
  
  		/* Advertise flow control */
  		if (ic->i_flowctl) {
  			unsigned int credits;
  
  			credits = IB_GET_POST_CREDITS(atomic_read(&ic->i_credits));
  			dp->dp_credit = cpu_to_be32(credits);
  			atomic_sub(IB_SET_POST_CREDITS(credits), &ic->i_credits);
  		}
  
  		conn_param->private_data = dp;
  		conn_param->private_data_len = sizeof(*dp);
  	}
  }
  
  static void rds_ib_cq_event_handler(struct ib_event *event, void *data)
  {
  	rdsdebug("event %u (%s) data %p
  ",
  		 event->event, rds_ib_event_str(event->event), data);
  }
  
  static void rds_ib_qp_event_handler(struct ib_event *event, void *data)
  {
  	struct rds_connection *conn = data;
  	struct rds_ib_connection *ic = conn->c_transport_data;
  
  	rdsdebug("conn %p ic %p event %u (%s)
  ", conn, ic, event->event,
  		 rds_ib_event_str(event->event));
  
  	switch (event->event) {
  	case IB_EVENT_COMM_EST:
  		rdma_notify(ic->i_cm_id, IB_EVENT_COMM_EST);
  		break;
  	default:
  		rdsdebug("Fatal QP Event %u (%s) "
  			"- connection %pI4->%pI4, reconnecting
  ",
  			event->event, rds_ib_event_str(event->event),
  			&conn->c_laddr, &conn->c_faddr);
  		rds_conn_drop(conn);
  		break;
  	}
  }
  
  /*
   * This needs to be very careful to not leave IS_ERR pointers around for
   * cleanup to trip over.
   */
  static int rds_ib_setup_qp(struct rds_connection *conn)
  {
  	struct rds_ib_connection *ic = conn->c_transport_data;
  	struct ib_device *dev = ic->i_cm_id->device;
  	struct ib_qp_init_attr attr;
  	struct rds_ib_device *rds_ibdev;
  	int ret;
  
  	/*
  	 * It's normal to see a null device if an incoming connection races
  	 * with device removal, so we don't print a warning.
  	 */
  	rds_ibdev = rds_ib_get_client_data(dev);
  	if (!rds_ibdev)
  		return -EOPNOTSUPP;
  
  	/* add the conn now so that connection establishment has the dev */
  	rds_ib_add_conn(rds_ibdev, conn);
  
  	if (rds_ibdev->max_wrs < ic->i_send_ring.w_nr + 1)
  		rds_ib_ring_resize(&ic->i_send_ring, rds_ibdev->max_wrs - 1);
  	if (rds_ibdev->max_wrs < ic->i_recv_ring.w_nr + 1)
  		rds_ib_ring_resize(&ic->i_recv_ring, rds_ibdev->max_wrs - 1);
  
  	/* Protection domain and memory range */
  	ic->i_pd = rds_ibdev->pd;
  	ic->i_mr = rds_ibdev->mr;
  
  	ic->i_send_cq = ib_create_cq(dev, rds_ib_send_cq_comp_handler,
  				     rds_ib_cq_event_handler, conn,
  				     ic->i_send_ring.w_nr + 1, 0);
  	if (IS_ERR(ic->i_send_cq)) {
  		ret = PTR_ERR(ic->i_send_cq);
  		ic->i_send_cq = NULL;
  		rdsdebug("ib_create_cq send failed: %d
  ", ret);
  		goto out;
  	}
  
  	ic->i_recv_cq = ib_create_cq(dev, rds_ib_recv_cq_comp_handler,
  				     rds_ib_cq_event_handler, conn,
  				     ic->i_recv_ring.w_nr, 0);
  	if (IS_ERR(ic->i_recv_cq)) {
  		ret = PTR_ERR(ic->i_recv_cq);
  		ic->i_recv_cq = NULL;
  		rdsdebug("ib_create_cq recv failed: %d
  ", ret);
  		goto out;
  	}
  
  	ret = ib_req_notify_cq(ic->i_send_cq, IB_CQ_NEXT_COMP);
  	if (ret) {
  		rdsdebug("ib_req_notify_cq send failed: %d
  ", ret);
  		goto out;
  	}
  
  	ret = ib_req_notify_cq(ic->i_recv_cq, IB_CQ_SOLICITED);
  	if (ret) {
  		rdsdebug("ib_req_notify_cq recv failed: %d
  ", ret);
  		goto out;
  	}
  
  	/* XXX negotiate max send/recv with remote? */
  	memset(&attr, 0, sizeof(attr));
  	attr.event_handler = rds_ib_qp_event_handler;
  	attr.qp_context = conn;
  	/* + 1 to allow for the single ack message */
  	attr.cap.max_send_wr = ic->i_send_ring.w_nr + 1;
  	attr.cap.max_recv_wr = ic->i_recv_ring.w_nr + 1;
  	attr.cap.max_send_sge = rds_ibdev->max_sge;
  	attr.cap.max_recv_sge = RDS_IB_RECV_SGE;
  	attr.sq_sig_type = IB_SIGNAL_REQ_WR;
  	attr.qp_type = IB_QPT_RC;
  	attr.send_cq = ic->i_send_cq;
  	attr.recv_cq = ic->i_recv_cq;
  
  	/*
  	 * XXX this can fail if max_*_wr is too large?  Are we supposed
  	 * to back off until we get a value that the hardware can support?
  	 */
  	ret = rdma_create_qp(ic->i_cm_id, ic->i_pd, &attr);
  	if (ret) {
  		rdsdebug("rdma_create_qp failed: %d
  ", ret);
  		goto out;
  	}
  
  	ic->i_send_hdrs = ib_dma_alloc_coherent(dev,
  					   ic->i_send_ring.w_nr *
  						sizeof(struct rds_header),
  					   &ic->i_send_hdrs_dma, GFP_KERNEL);
  	if (!ic->i_send_hdrs) {
  		ret = -ENOMEM;
  		rdsdebug("ib_dma_alloc_coherent send failed
  ");
  		goto out;
  	}
  
  	ic->i_recv_hdrs = ib_dma_alloc_coherent(dev,
  					   ic->i_recv_ring.w_nr *
  						sizeof(struct rds_header),
  					   &ic->i_recv_hdrs_dma, GFP_KERNEL);
  	if (!ic->i_recv_hdrs) {
  		ret = -ENOMEM;
  		rdsdebug("ib_dma_alloc_coherent recv failed
  ");
  		goto out;
  	}
  
  	ic->i_ack = ib_dma_alloc_coherent(dev, sizeof(struct rds_header),
  				       &ic->i_ack_dma, GFP_KERNEL);
  	if (!ic->i_ack) {
  		ret = -ENOMEM;
  		rdsdebug("ib_dma_alloc_coherent ack failed
  ");
  		goto out;
  	}
  
  	ic->i_sends = vzalloc_node(ic->i_send_ring.w_nr * sizeof(struct rds_ib_send_work),
  				   ibdev_to_node(dev));
  	if (!ic->i_sends) {
  		ret = -ENOMEM;
  		rdsdebug("send allocation failed
  ");
  		goto out;
  	}
  
  	ic->i_recvs = vzalloc_node(ic->i_recv_ring.w_nr * sizeof(struct rds_ib_recv_work),
  				   ibdev_to_node(dev));
  	if (!ic->i_recvs) {
  		ret = -ENOMEM;
  		rdsdebug("recv allocation failed
  ");
  		goto out;
  	}
  
  	rds_ib_recv_init_ack(ic);
  
  	rdsdebug("conn %p pd %p mr %p cq %p %p
  ", conn, ic->i_pd, ic->i_mr,
  		 ic->i_send_cq, ic->i_recv_cq);
  
  out:
  	rds_ib_dev_put(rds_ibdev);
  	return ret;
  }
  
  static u32 rds_ib_protocol_compatible(struct rdma_cm_event *event)
  {
  	const struct rds_ib_connect_private *dp = event->param.conn.private_data;
  	u16 common;
  	u32 version = 0;
  
  	/*
  	 * rdma_cm private data is odd - when there is any private data in the
  	 * request, we will be given a pretty large buffer without telling us the
  	 * original size. The only way to tell the difference is by looking at
  	 * the contents, which are initialized to zero.
  	 * If the protocol version fields aren't set, this is a connection attempt
  	 * from an older version. This could could be 3.0 or 2.0 - we can't tell.
  	 * We really should have changed this for OFED 1.3 :-(
  	 */
  
  	/* Be paranoid. RDS always has privdata */
  	if (!event->param.conn.private_data_len) {
  		printk(KERN_NOTICE "RDS incoming connection has no private data, "
  			"rejecting
  ");
  		return 0;
  	}
  
  	/* Even if len is crap *now* I still want to check it. -ASG */
  	if (event->param.conn.private_data_len < sizeof (*dp) ||
  	    dp->dp_protocol_major == 0)
  		return RDS_PROTOCOL_3_0;
  
  	common = be16_to_cpu(dp->dp_protocol_minor_mask) & RDS_IB_SUPPORTED_PROTOCOLS;
  	if (dp->dp_protocol_major == 3 && common) {
  		version = RDS_PROTOCOL_3_0;
  		while ((common >>= 1) != 0)
  			version++;
  	} else
  		printk_ratelimited(KERN_NOTICE "RDS: Connection from %pI4 using incompatible protocol version %u.%u
  ",
  				&dp->dp_saddr,
  				dp->dp_protocol_major,
  				dp->dp_protocol_minor);
  	return version;
  }
  
  int rds_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
  				    struct rdma_cm_event *event)
  {
  	__be64 lguid = cm_id->route.path_rec->sgid.global.interface_id;
  	__be64 fguid = cm_id->route.path_rec->dgid.global.interface_id;
  	const struct rds_ib_connect_private *dp = event->param.conn.private_data;
  	struct rds_ib_connect_private dp_rep;
  	struct rds_connection *conn = NULL;
  	struct rds_ib_connection *ic = NULL;
  	struct rdma_conn_param conn_param;
  	u32 version;
  	int err = 1, destroy = 1;
  
  	/* Check whether the remote protocol version matches ours. */
  	version = rds_ib_protocol_compatible(event);
  	if (!version)
  		goto out;
  
  	rdsdebug("saddr %pI4 daddr %pI4 RDSv%u.%u lguid 0x%llx fguid "
  		 "0x%llx
  ", &dp->dp_saddr, &dp->dp_daddr,
  		 RDS_PROTOCOL_MAJOR(version), RDS_PROTOCOL_MINOR(version),
  		 (unsigned long long)be64_to_cpu(lguid),
  		 (unsigned long long)be64_to_cpu(fguid));
  
  	conn = rds_conn_create(dp->dp_daddr, dp->dp_saddr, &rds_ib_transport,
  			       GFP_KERNEL);
  	if (IS_ERR(conn)) {
  		rdsdebug("rds_conn_create failed (%ld)
  ", PTR_ERR(conn));
  		conn = NULL;
  		goto out;
  	}
  
  	/*
  	 * The connection request may occur while the
  	 * previous connection exist, e.g. in case of failover.
  	 * But as connections may be initiated simultaneously
  	 * by both hosts, we have a random backoff mechanism -
  	 * see the comment above rds_queue_reconnect()
  	 */
  	mutex_lock(&conn->c_cm_lock);
  	if (!rds_conn_transition(conn, RDS_CONN_DOWN, RDS_CONN_CONNECTING)) {
  		if (rds_conn_state(conn) == RDS_CONN_UP) {
  			rdsdebug("incoming connect while connecting
  ");
  			rds_conn_drop(conn);
  			rds_ib_stats_inc(s_ib_listen_closed_stale);
  		} else
  		if (rds_conn_state(conn) == RDS_CONN_CONNECTING) {
  			/* Wait and see - our connect may still be succeeding */
  			rds_ib_stats_inc(s_ib_connect_raced);
  		}
  		goto out;
  	}
  
  	ic = conn->c_transport_data;
  
  	rds_ib_set_protocol(conn, version);
  	rds_ib_set_flow_control(conn, be32_to_cpu(dp->dp_credit));
  
  	/* If the peer gave us the last packet it saw, process this as if
  	 * we had received a regular ACK. */
  	if (dp->dp_ack_seq)
  		rds_send_drop_acked(conn, be64_to_cpu(dp->dp_ack_seq), NULL);
  
  	BUG_ON(cm_id->context);
  	BUG_ON(ic->i_cm_id);
  
  	ic->i_cm_id = cm_id;
  	cm_id->context = conn;
  
  	/* We got halfway through setting up the ib_connection, if we
  	 * fail now, we have to take the long route out of this mess. */
  	destroy = 0;
  
  	err = rds_ib_setup_qp(conn);
  	if (err) {
  		rds_ib_conn_error(conn, "rds_ib_setup_qp failed (%d)
  ", err);
  		goto out;
  	}
  
  	rds_ib_cm_fill_conn_param(conn, &conn_param, &dp_rep, version,
  		event->param.conn.responder_resources,
  		event->param.conn.initiator_depth);
  
  	/* rdma_accept() calls rdma_reject() internally if it fails */
  	err = rdma_accept(cm_id, &conn_param);
  	if (err)
  		rds_ib_conn_error(conn, "rdma_accept failed (%d)
  ", err);
  
  out:
  	if (conn)
  		mutex_unlock(&conn->c_cm_lock);
  	if (err)
  		rdma_reject(cm_id, NULL, 0);
  	return destroy;
  }
  
  
  int rds_ib_cm_initiate_connect(struct rdma_cm_id *cm_id)
  {
  	struct rds_connection *conn = cm_id->context;
  	struct rds_ib_connection *ic = conn->c_transport_data;
  	struct rdma_conn_param conn_param;
  	struct rds_ib_connect_private dp;
  	int ret;
  
  	/* If the peer doesn't do protocol negotiation, we must
  	 * default to RDSv3.0 */
  	rds_ib_set_protocol(conn, RDS_PROTOCOL_3_0);
  	ic->i_flowctl = rds_ib_sysctl_flow_control;	/* advertise flow control */
  
  	ret = rds_ib_setup_qp(conn);
  	if (ret) {
  		rds_ib_conn_error(conn, "rds_ib_setup_qp failed (%d)
  ", ret);
  		goto out;
  	}
  
  	rds_ib_cm_fill_conn_param(conn, &conn_param, &dp, RDS_PROTOCOL_VERSION,
  		UINT_MAX, UINT_MAX);
  	ret = rdma_connect(cm_id, &conn_param);
  	if (ret)
  		rds_ib_conn_error(conn, "rdma_connect failed (%d)
  ", ret);
  
  out:
  	/* Beware - returning non-zero tells the rdma_cm to destroy
  	 * the cm_id. We should certainly not do it as long as we still
  	 * "own" the cm_id. */
  	if (ret) {
  		if (ic->i_cm_id == cm_id)
  			ret = 0;
  	}
  	return ret;
  }
  
  int rds_ib_conn_connect(struct rds_connection *conn)
  {
  	struct rds_ib_connection *ic = conn->c_transport_data;
  	struct sockaddr_in src, dest;
  	int ret;
  
  	/* XXX I wonder what affect the port space has */
  	/* delegate cm event handler to rdma_transport */
  	ic->i_cm_id = rdma_create_id(rds_rdma_cm_event_handler, conn,
  				     RDMA_PS_TCP, IB_QPT_RC);
  	if (IS_ERR(ic->i_cm_id)) {
  		ret = PTR_ERR(ic->i_cm_id);
  		ic->i_cm_id = NULL;
  		rdsdebug("rdma_create_id() failed: %d
  ", ret);
  		goto out;
  	}
  
  	rdsdebug("created cm id %p for conn %p
  ", ic->i_cm_id, conn);
  
  	src.sin_family = AF_INET;
  	src.sin_addr.s_addr = (__force u32)conn->c_laddr;
  	src.sin_port = (__force u16)htons(0);
  
  	dest.sin_family = AF_INET;
  	dest.sin_addr.s_addr = (__force u32)conn->c_faddr;
  	dest.sin_port = (__force u16)htons(RDS_PORT);
  
  	ret = rdma_resolve_addr(ic->i_cm_id, (struct sockaddr *)&src,
  				(struct sockaddr *)&dest,
  				RDS_RDMA_RESOLVE_TIMEOUT_MS);
  	if (ret) {
  		rdsdebug("addr resolve failed for cm id %p: %d
  ", ic->i_cm_id,
  			 ret);
  		rdma_destroy_id(ic->i_cm_id);
  		ic->i_cm_id = NULL;
  	}
  
  out:
  	return ret;
  }
  
  /*
   * This is so careful about only cleaning up resources that were built up
   * so that it can be called at any point during startup.  In fact it
   * can be called multiple times for a given connection.
   */
  void rds_ib_conn_shutdown(struct rds_connection *conn)
  {
  	struct rds_ib_connection *ic = conn->c_transport_data;
  	int err = 0;
  
  	rdsdebug("cm %p pd %p cq %p %p qp %p
  ", ic->i_cm_id,
  		 ic->i_pd, ic->i_send_cq, ic->i_recv_cq,
  		 ic->i_cm_id ? ic->i_cm_id->qp : NULL);
  
  	if (ic->i_cm_id) {
  		struct ib_device *dev = ic->i_cm_id->device;
  
  		rdsdebug("disconnecting cm %p
  ", ic->i_cm_id);
  		err = rdma_disconnect(ic->i_cm_id);
  		if (err) {
  			/* Actually this may happen quite frequently, when
  			 * an outgoing connect raced with an incoming connect.
  			 */
  			rdsdebug("failed to disconnect, cm: %p err %d
  ",
  				ic->i_cm_id, err);
  		}
  
  		/*
  		 * We want to wait for tx and rx completion to finish
  		 * before we tear down the connection, but we have to be
  		 * careful not to get stuck waiting on a send ring that
  		 * only has unsignaled sends in it.  We've shutdown new
  		 * sends before getting here so by waiting for signaled
  		 * sends to complete we're ensured that there will be no
  		 * more tx processing.
  		 */
  		wait_event(rds_ib_ring_empty_wait,
  			   rds_ib_ring_empty(&ic->i_recv_ring) &&
  			   (atomic_read(&ic->i_signaled_sends) == 0));
  		tasklet_kill(&ic->i_recv_tasklet);
  
  		if (ic->i_send_hdrs)
  			ib_dma_free_coherent(dev,
  					   ic->i_send_ring.w_nr *
  						sizeof(struct rds_header),
  					   ic->i_send_hdrs,
  					   ic->i_send_hdrs_dma);
  
  		if (ic->i_recv_hdrs)
  			ib_dma_free_coherent(dev,
  					   ic->i_recv_ring.w_nr *
  						sizeof(struct rds_header),
  					   ic->i_recv_hdrs,
  					   ic->i_recv_hdrs_dma);
  
  		if (ic->i_ack)
  			ib_dma_free_coherent(dev, sizeof(struct rds_header),
  					     ic->i_ack, ic->i_ack_dma);
  
  		if (ic->i_sends)
  			rds_ib_send_clear_ring(ic);
  		if (ic->i_recvs)
  			rds_ib_recv_clear_ring(ic);
  
  		if (ic->i_cm_id->qp)
  			rdma_destroy_qp(ic->i_cm_id);
  		if (ic->i_send_cq)
  			ib_destroy_cq(ic->i_send_cq);
  		if (ic->i_recv_cq)
  			ib_destroy_cq(ic->i_recv_cq);
  		rdma_destroy_id(ic->i_cm_id);
  
  		/*
  		 * Move connection back to the nodev list.
  		 */
  		if (ic->rds_ibdev)
  			rds_ib_remove_conn(ic->rds_ibdev, conn);
  
  		ic->i_cm_id = NULL;
  		ic->i_pd = NULL;
  		ic->i_mr = NULL;
  		ic->i_send_cq = NULL;
  		ic->i_recv_cq = NULL;
  		ic->i_send_hdrs = NULL;
  		ic->i_recv_hdrs = NULL;
  		ic->i_ack = NULL;
  	}
  	BUG_ON(ic->rds_ibdev);
  
  	/* Clear pending transmit */
  	if (ic->i_data_op) {
  		struct rds_message *rm;
  
  		rm = container_of(ic->i_data_op, struct rds_message, data);
  		rds_message_put(rm);
  		ic->i_data_op = NULL;
  	}
  
  	/* Clear the ACK state */
  	clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
  #ifdef KERNEL_HAS_ATOMIC64
  	atomic64_set(&ic->i_ack_next, 0);
  #else
  	ic->i_ack_next = 0;
  #endif
  	ic->i_ack_recv = 0;
  
  	/* Clear flow control state */
  	ic->i_flowctl = 0;
  	atomic_set(&ic->i_credits, 0);
  
  	rds_ib_ring_init(&ic->i_send_ring, rds_ib_sysctl_max_send_wr);
  	rds_ib_ring_init(&ic->i_recv_ring, rds_ib_sysctl_max_recv_wr);
  
  	if (ic->i_ibinc) {
  		rds_inc_put(&ic->i_ibinc->ii_inc);
  		ic->i_ibinc = NULL;
  	}
  
  	vfree(ic->i_sends);
  	ic->i_sends = NULL;
  	vfree(ic->i_recvs);
  	ic->i_recvs = NULL;
  }
  
  int rds_ib_conn_alloc(struct rds_connection *conn, gfp_t gfp)
  {
  	struct rds_ib_connection *ic;
  	unsigned long flags;
  	int ret;
  
  	/* XXX too lazy? */
  	ic = kzalloc(sizeof(struct rds_ib_connection), gfp);
  	if (!ic)
  		return -ENOMEM;
  
  	ret = rds_ib_recv_alloc_caches(ic);
  	if (ret) {
  		kfree(ic);
  		return ret;
  	}
  
  	INIT_LIST_HEAD(&ic->ib_node);
  	tasklet_init(&ic->i_recv_tasklet, rds_ib_recv_tasklet_fn,
  		     (unsigned long) ic);
  	mutex_init(&ic->i_recv_mutex);
  #ifndef KERNEL_HAS_ATOMIC64
  	spin_lock_init(&ic->i_ack_lock);
  #endif
  	atomic_set(&ic->i_signaled_sends, 0);
  
  	/*
  	 * rds_ib_conn_shutdown() waits for these to be emptied so they
  	 * must be initialized before it can be called.
  	 */
  	rds_ib_ring_init(&ic->i_send_ring, rds_ib_sysctl_max_send_wr);
  	rds_ib_ring_init(&ic->i_recv_ring, rds_ib_sysctl_max_recv_wr);
  
  	ic->conn = conn;
  	conn->c_transport_data = ic;
  
  	spin_lock_irqsave(&ib_nodev_conns_lock, flags);
  	list_add_tail(&ic->ib_node, &ib_nodev_conns);
  	spin_unlock_irqrestore(&ib_nodev_conns_lock, flags);
  
  
  	rdsdebug("conn %p conn ic %p
  ", conn, conn->c_transport_data);
  	return 0;
  }
  
  /*
   * Free a connection. Connection must be shut down and not set for reconnect.
   */
  void rds_ib_conn_free(void *arg)
  {
  	struct rds_ib_connection *ic = arg;
  	spinlock_t	*lock_ptr;
  
  	rdsdebug("ic %p
  ", ic);
  
  	/*
  	 * Conn is either on a dev's list or on the nodev list.
  	 * A race with shutdown() or connect() would cause problems
  	 * (since rds_ibdev would change) but that should never happen.
  	 */
  	lock_ptr = ic->rds_ibdev ? &ic->rds_ibdev->spinlock : &ib_nodev_conns_lock;
  
  	spin_lock_irq(lock_ptr);
  	list_del(&ic->ib_node);
  	spin_unlock_irq(lock_ptr);
  
  	rds_ib_recv_free_caches(ic);
  
  	kfree(ic);
  }
  
  
  /*
   * An error occurred on the connection
   */
  void
  __rds_ib_conn_error(struct rds_connection *conn, const char *fmt, ...)
  {
  	va_list ap;
  
  	rds_conn_drop(conn);
  
  	va_start(ap, fmt);
  	vprintk(fmt, ap);
  	va_end(ap);
  }