RDS/IB: Infiniband transport

Registers as an RDS transport and an IB client, and uses IB CM
API to allocate ids, queue pairs, and the rest of that fun stuff.

Signed-off-by: Andy Grover <andy.grover@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 726 insertions, 0 deletions

diff --git a/net/rds/ib_cm.c b/net/rds/ib_cm.c
new file mode 100644
index 00000000000..0532237bd12
--- /dev/null
+++ b/net/rds/ib_cm.c
@@ -0,0 +1,726 @@
+/*
+ * 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/vmalloc.h>
+
+#include "rds.h"
+#include "ib.h"
+
+/*
+ * 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\n", -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 rds_ib_device *rds_ibdev;
+        struct ib_qp_attr qp_attr;
+        int err;
+
+        if (event->param.conn.private_data_len) {
+                dp = event->param.conn.private_data;
+
+                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));
+        }
+
+        printk(KERN_NOTICE "RDS/IB: connected to %pI4 version %u.%u%s\n",
+                        &conn->c_laddr,
+                        RDS_PROTOCOL_MAJOR(conn->c_version),
+                        RDS_PROTOCOL_MINOR(conn->c_version),
+                        ic->i_flowctl ? ", flow control" : "");
+
+        /* 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\n", err);
+
+        /* update ib_device with this local ipaddr & conn */
+        rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rds_ib_client);
+        err = rds_ib_update_ipaddr(rds_ibdev, conn->c_laddr);
+        if (err)
+                printk(KERN_ERR "rds_ib_update_ipaddr failed (%d)\n", err);
+        err = rds_ib_add_conn(rds_ibdev, conn);
+        if (err)
+                printk(KERN_ERR "rds_ib_add_conn failed (%d)\n", 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)
+{
+        memset(conn_param, 0, sizeof(struct rdma_conn_param));
+        /* XXX tune these? */
+        conn_param->responder_resources = 1;
+        conn_param->initiator_depth = 1;
+        conn_param->retry_count = 7;
+        conn_param->rnr_retry_count = 7;
+
+        if (dp) {
+                struct rds_ib_connection *ic = conn->c_transport_data;
+
+                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 data %p\n", 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\n", conn, ic, event->event);
+
+        switch (event->event) {
+        case IB_EVENT_COMM_EST:
+                rdma_notify(ic->i_cm_id, IB_EVENT_COMM_EST);
+                break;
+        default:
+                printk(KERN_WARNING "RDS/ib: unhandled QP event %u "
+                       "on connection to %pI4\n", event->event,
+                       &conn->c_faddr);
+                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;
+
+        /* rds_ib_add_one creates a rds_ib_device object per IB device,
+         * and allocates a protection domain, memory range and FMR pool
+         * for each.  If that fails for any reason, it will not register
+         * the rds_ibdev at all.
+         */
+        rds_ibdev = ib_get_client_data(dev, &rds_ib_client);
+        if (rds_ibdev == NULL) {
+                if (printk_ratelimit())
+                        printk(KERN_NOTICE "RDS/IB: No client_data for device %s\n",
+                                        dev->name);
+                return -EOPNOTSUPP;
+        }
+
+        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\n", 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\n", 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\n", 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\n", 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\n", 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 == NULL) {
+                ret = -ENOMEM;
+                rdsdebug("ib_dma_alloc_coherent send failed\n");
+                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 == NULL) {
+                ret = -ENOMEM;
+                rdsdebug("ib_dma_alloc_coherent recv failed\n");
+                goto out;
+        }
+
+        ic->i_ack = ib_dma_alloc_coherent(dev, sizeof(struct rds_header),
+                                       &ic->i_ack_dma, GFP_KERNEL);
+        if (ic->i_ack == NULL) {
+                ret = -ENOMEM;
+                rdsdebug("ib_dma_alloc_coherent ack failed\n");
+                goto out;
+        }
+
+        ic->i_sends = vmalloc(ic->i_send_ring.w_nr * sizeof(struct rds_ib_send_work));
+        if (ic->i_sends == NULL) {
+                ret = -ENOMEM;
+                rdsdebug("send allocation failed\n");
+                goto out;
+        }
+        rds_ib_send_init_ring(ic);
+
+        ic->i_recvs = vmalloc(ic->i_recv_ring.w_nr * sizeof(struct rds_ib_recv_work));
+        if (ic->i_recvs == NULL) {
+                ret = -ENOMEM;
+                rdsdebug("recv allocation failed\n");
+                goto out;
+        }
+
+        rds_ib_recv_init_ring(ic);
+        rds_ib_recv_init_ack(ic);
+
+        /* Post receive buffers - as a side effect, this will update
+         * the posted credit count. */
+        rds_ib_recv_refill(conn, GFP_KERNEL, GFP_HIGHUSER, 1);
+
+        rdsdebug("conn %p pd %p mr %p cq %p %p\n", conn, ic->i_pd, ic->i_mr,
+                 ic->i_send_cq, ic->i_recv_cq);
+
+out:
+        return ret;
+}
+
+static u32 rds_ib_protocol_compatible(const struct rds_ib_connect_private *dp)
+{
+        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 :-( */
+        if (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 if (printk_ratelimit()) {
+                printk(KERN_NOTICE "RDS: Connection from %pI4 using "
+                        "incompatible protocol version %u.%u\n",
+                        &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, destroy = 1;
+
+        /* Check whether the remote protocol version matches ours. */
+        version = rds_ib_protocol_compatible(dp);
+        if (!version)
+                goto out;
+
+        rdsdebug("saddr %pI4 daddr %pI4 RDSv%u.%u lguid 0x%llx fguid "
+                 "0x%llx\n", &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)\n", 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\n");
+                        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);
+                }
+                mutex_unlock(&conn->c_cm_lock);
+                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)\n", err);
+                goto out;
+        }
+
+        rds_ib_cm_fill_conn_param(conn, &conn_param, &dp_rep, version);
+
+        /* rdma_accept() calls rdma_reject() internally if it fails */
+        err = rdma_accept(cm_id, &conn_param);
+        mutex_unlock(&conn->c_cm_lock);
+        if (err) {
+                rds_ib_conn_error(conn, "rdma_accept failed (%d)\n", err);
+                goto out;
+        }
+
+        return 0;
+
+out:
+        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)\n", ret);
+                goto out;
+        }
+
+        rds_ib_cm_fill_conn_param(conn, &conn_param, &dp, RDS_PROTOCOL_VERSION);
+
+        ret = rdma_connect(cm_id, &conn_param);
+        if (ret)
+                rds_ib_conn_error(conn, "rdma_connect failed (%d)\n", 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);
+        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\n", ret);
+                goto out;
+        }
+
+        rdsdebug("created cm id %p for conn %p\n", 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\n", 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\n", 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\n", 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\n",
+                                ic->i_cm_id, err);
+                }
+
+                wait_event(rds_ib_ring_empty_wait,
+                        rds_ib_ring_empty(&ic->i_send_ring) &&
+                        rds_ib_ring_empty(&ic->i_recv_ring));
+
+                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) {
+
+                        spin_lock_irq(&ic->rds_ibdev->spinlock);
+                        BUG_ON(list_empty(&ic->ib_node));
+                        list_del(&ic->ib_node);
+                        spin_unlock_irq(&ic->rds_ibdev->spinlock);
+
+                        spin_lock_irq(&ib_nodev_conns_lock);
+                        list_add_tail(&ic->ib_node, &ib_nodev_conns);
+                        spin_unlock_irq(&ib_nodev_conns_lock);
+                        ic->rds_ibdev = NULL;
+                }
+
+                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_rm) {
+                rds_message_put(ic->i_rm);
+                ic->i_rm = NULL;
+        }
+
+        /* Clear the ACK state */
+        clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
+        rds_ib_set_64bit(&ic->i_ack_next, 0);
+        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;
+
+        /* XXX too lazy? */
+        ic = kzalloc(sizeof(struct rds_ib_connection), GFP_KERNEL);
+        if (ic == NULL)
+                return -ENOMEM;
+
+        INIT_LIST_HEAD(&ic->ib_node);
+        mutex_init(&ic->i_recv_mutex);
+
+        /*
+         * 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\n", conn, conn->c_transport_data);
+        return 0;
+}
+
+void rds_ib_conn_free(void *arg)
+{
+        struct rds_ib_connection *ic = arg;
+        rdsdebug("ic %p\n", ic);
+        list_del(&ic->ib_node);
+        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);
+}