clients/rdsv3/ib_cm.c

/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * This file contains code imported from the OFED rds source file ib_cm.c
 * Oracle elects to have and use the contents of ib_cm.c under and governed
 * by the OpenIB.org BSD license (see below for full license text). However,
 * the following notice accompanied the original version of this file:
 */

/*
 * 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 <sys/rds.h>

#include <sys/ib/clients/of/ofed_kernel.h>
#include <sys/ib/clients/of/rdma/ib_addr.h>
#include <sys/ib/clients/of/rdma/rdma_cm.h>

#include <sys/ib/clients/rdsv3/rdsv3.h>
#include <sys/ib/clients/rdsv3/ib.h>
#include <sys/ib/clients/rdsv3/rdsv3_debug.h>

extern int rdsv3_enable_snd_cq;

/*
 * Set the selected protocol version
 */
static void
rdsv3_ib_set_protocol(struct rdsv3_connection *conn, unsigned int version)
{
    RDSV3_DPRINTF4("rdsv3_ib_set_protocol", "conn: %p version: %d",
        conn, version);
    conn->c_version = version;
}

/*
 * Set up flow control
 */
static void
rdsv3_ib_set_flow_control(struct rdsv3_connection *conn, uint32_t credits)
{
    struct rdsv3_ib_connection *ic = conn->c_transport_data;

    RDSV3_DPRINTF2("rdsv3_ib_set_flow_control",
        "Enter: conn: %p credits: %d", conn, credits);

    if (rdsv3_ib_sysctl_flow_control && credits != 0) {
        /* We're doing flow control */
        ic->i_flowctl = 1;
        rdsv3_ib_send_add_credits(conn, credits);
    } else {
        ic->i_flowctl = 0;
    }

    RDSV3_DPRINTF2("rdsv3_ib_set_flow_control",
        "Return: conn: %p credits: %d",
        conn, credits);
}

/*
 * 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
rdsv3_ib_tune_rnr(struct rdsv3_ib_connection *ic, struct ib_qp_attr *attr)
{
    int ret;

    RDSV3_DPRINTF2("rdsv3_ib_tune_rnr", "Enter ic: %p attr: %p",
        ic, attr);

    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)
        RDSV3_DPRINTF2("rdsv3_ib_tune_rnr",
            "ib_modify_qp(IB_QP_MIN_RNR_TIMER): err=%d", -ret);
}

/*
 * Connection established.
 * We get here for both outgoing and incoming connection.
 */
void
rdsv3_ib_cm_connect_complete(struct rdsv3_connection *conn,
    struct rdma_cm_event *event)
{
    const struct rdsv3_ib_connect_private *dp = NULL;
    struct rdsv3_ib_connection *ic = conn->c_transport_data;
    struct rdsv3_ib_device *rds_ibdev =
        ib_get_client_data(ic->i_cm_id->device, &rdsv3_ib_client);
    struct ib_qp_attr qp_attr;
    int err;

    RDSV3_DPRINTF2("rdsv3_ib_cm_connect_complete",
        "Enter conn: %p event: %p", conn, event);

    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) {
            rdsv3_ib_set_protocol(conn,
                RDS_PROTOCOL(dp->dp_protocol_major,
                dp->dp_protocol_minor));
            rdsv3_ib_set_flow_control(conn,
                ntohl(dp->dp_credit));
        }
    }

    if (conn->c_version < RDS_PROTOCOL(3, 1)) {
        RDSV3_DPRINTF2("rdsv3_ib_cm_connect_complete",
            "RDS/IB: Connection to %u.%u.%u.%u version %u.%u failed",
            NIPQUAD(conn->c_faddr),
            RDS_PROTOCOL_MAJOR(conn->c_version),
            RDS_PROTOCOL_MINOR(conn->c_version));
        rdsv3_conn_destroy(conn);
        return;
    } else {
        RDSV3_DPRINTF2("rdsv3_ib_cm_connect_complete",
            "RDS/IB: connected to %u.%u.%u.%u version %u.%u%s",
            NIPQUAD(conn->c_faddr),
            RDS_PROTOCOL_MAJOR(conn->c_version),
            RDS_PROTOCOL_MINOR(conn->c_version),
            ic->i_flowctl ? ", flow control" : "");
    }

    ASSERT(ic->i_soft_cq == NULL);
    ic->i_soft_cq = rdsv3_af_intr_thr_create(rdsv3_ib_tasklet_fn,
        (void *)ic, SCQ_INTR_BIND_CPU, rds_ibdev->aft_hcagp,
        ic->i_cq->ibt_cq);
    if (rdsv3_enable_snd_cq) {
        ic->i_snd_soft_cq = rdsv3_af_intr_thr_create(
            rdsv3_ib_snd_tasklet_fn,
            (void *)ic, SCQ_INTR_BIND_CPU, rds_ibdev->aft_hcagp,
            ic->i_snd_cq->ibt_cq);
    }
    /* rdsv3_ib_refill_fn is expecting i_max_recv_alloc set */
    ic->i_max_recv_alloc = rdsv3_ib_sysctl_max_recv_allocation;
    ic->i_refill_rq = rdsv3_af_thr_create(rdsv3_ib_refill_fn, (void *)conn,
        SCQ_WRK_BIND_CPU, rds_ibdev->aft_hcagp);
    rdsv3_af_grp_draw(rds_ibdev->aft_hcagp);

    (void) ib_req_notify_cq(ic->i_cq, IB_CQ_SOLICITED);
    if (rdsv3_enable_snd_cq) {
        (void) ib_req_notify_cq(ic->i_snd_cq, IB_CQ_NEXT_COMP);
    }

    /*
     * 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.
     */
    rdsv3_ib_send_init_ring(ic);
    rdsv3_ib_recv_init_ring(ic);
    /*
     * Post receive buffers - as a side effect, this will update
     * the posted credit count.
     */
    (void) rdsv3_ib_recv_refill(conn, 1);

    /* Tune RNR behavior */
    rdsv3_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)
        RDSV3_DPRINTF2("rdsv3_ib_cm_connect_complete",
            "ib_modify_qp(IB_QP_STATE, RTS): err=%d", err);

    /* update ib_device with this local ipaddr & conn */
    err = rdsv3_ib_update_ipaddr(rds_ibdev, conn->c_laddr);
    if (err)
        RDSV3_DPRINTF2("rdsv3_ib_cm_connect_complete",
            "rdsv3_ib_update_ipaddr failed (%d)", err);
    rdsv3_ib_add_conn(rds_ibdev, conn);

    /*
     * 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)
        rdsv3_send_drop_acked(conn, ntohll(dp->dp_ack_seq), NULL);

    rdsv3_connect_complete(conn);

    RDSV3_DPRINTF2("rdsv3_ib_cm_connect_complete",
        "Return conn: %p event: %p",
        conn, event);
}

static void
rdsv3_ib_cm_fill_conn_param(struct rdsv3_connection *conn,
    struct rdma_conn_param *conn_param,
    struct rdsv3_ib_connect_private *dp,
    uint32_t protocol_version,
    uint32_t max_responder_resources,
    uint32_t max_initiator_depth)
{
    struct rdsv3_ib_connection *ic = conn->c_transport_data;
    struct rdsv3_ib_device *rds_ibdev;

    RDSV3_DPRINTF2("rdsv3_ib_cm_fill_conn_param",
        "Enter conn: %p conn_param: %p private: %p version: %d",
        conn, conn_param, dp, protocol_version);

    (void) memset(conn_param, 0, sizeof (struct rdma_conn_param));

    rds_ibdev = ib_get_client_data(ic->i_cm_id->device, &rdsv3_ib_client);

    conn_param->responder_resources =
        MIN(rds_ibdev->max_responder_resources, max_responder_resources);
    conn_param->initiator_depth =
        MIN(rds_ibdev->max_initiator_depth, max_initiator_depth);
    conn_param->retry_count = min(rdsv3_ib_retry_count, 7);
    conn_param->rnr_retry_count = 7;

    if (dp) {
        (void) 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 =
            htons(RDSV3_IB_SUPPORTED_PROTOCOLS);
        dp->dp_ack_seq = rdsv3_ib_piggyb_ack(ic);

        /* Advertise flow control */
        if (ic->i_flowctl) {
            unsigned int credits;

            credits = IB_GET_POST_CREDITS(
                atomic_get(&ic->i_credits));
            dp->dp_credit = htonl(credits);
            atomic_add_32(&ic->i_credits,
                -IB_SET_POST_CREDITS(credits));
        }

        conn_param->private_data = dp;
        conn_param->private_data_len = sizeof (*dp);
    }

    RDSV3_DPRINTF2("rdsv3_ib_cm_fill_conn_param",
        "Return conn: %p conn_param: %p private: %p version: %d",
        conn, conn_param, dp, protocol_version);
}

static void
rdsv3_ib_cq_event_handler(struct ib_event *event, void *data)
{
    RDSV3_DPRINTF3("rdsv3_ib_cq_event_handler", "event %u data %p",
        event->event, data);
}

static void
rdsv3_ib_snd_cq_comp_handler(struct ib_cq *cq, void *context)
{
    struct rdsv3_connection *conn = context;
    struct rdsv3_ib_connection *ic = conn->c_transport_data;

    RDSV3_DPRINTF4("rdsv3_ib_snd_cq_comp_handler",
        "Enter(conn: %p ic: %p cq: %p)", conn, ic, cq);

    rdsv3_af_thr_fire(ic->i_snd_soft_cq);
}

void
rdsv3_ib_snd_tasklet_fn(void *data)
{
    struct rdsv3_ib_connection *ic = (struct rdsv3_ib_connection *)data;
    struct rdsv3_connection *conn = ic->conn;
    struct rdsv3_ib_ack_state ack_state = { 0, };
    ibt_wc_t wc;
    uint_t polled;

    RDSV3_DPRINTF4("rdsv3_ib_snd_tasklet_fn",
        "Enter(conn: %p ic: %p)", conn, ic);

    /*
     * Poll in a loop before and after enabling the next event
     */
    while (ibt_poll_cq(RDSV3_CQ2CQHDL(ic->i_snd_cq), &wc, 1, &polled) ==
        IBT_SUCCESS) {
        RDSV3_DPRINTF4("rdsv3_ib_snd_tasklet_fn",
            "wc_id 0x%llx type %d status %u byte_len %u imm_data %u\n",
            (unsigned long long)wc.wc_id, wc.wc_type, wc.wc_status,
            wc.wc_bytes_xfer, ntohl(wc.wc_immed_data));

        ASSERT(wc.wc_id & RDSV3_IB_SEND_OP);
        rdsv3_ib_send_cqe_handler(ic, &wc);
    }
    (void) ibt_enable_cq_notify(RDSV3_CQ2CQHDL(ic->i_snd_cq),
        IBT_NEXT_COMPLETION);
    while (ibt_poll_cq(RDSV3_CQ2CQHDL(ic->i_snd_cq), &wc, 1, &polled) ==
        IBT_SUCCESS) {
        RDSV3_DPRINTF4("rdsv3_ib_snd_tasklet_fn",
            "wc_id 0x%llx type %d status %u byte_len %u imm_data %u\n",
            (unsigned long long)wc.wc_id, wc.wc_type, wc.wc_status,
            wc.wc_bytes_xfer, ntohl(wc.wc_immed_data));

        ASSERT(wc.wc_id & RDSV3_IB_SEND_OP);
        rdsv3_ib_send_cqe_handler(ic, &wc);
    }
}

static void
rdsv3_ib_cq_comp_handler(struct ib_cq *cq, void *context)
{
    struct rdsv3_connection *conn = context;
    struct rdsv3_ib_connection *ic = conn->c_transport_data;

    RDSV3_DPRINTF4("rdsv3_ib_cq_comp_handler",
        "Enter(conn: %p cq: %p)", conn, cq);

    rdsv3_ib_stats_inc(s_ib_evt_handler_call);

    rdsv3_af_thr_fire(ic->i_soft_cq);
}

void
rdsv3_ib_refill_fn(void *data)
{
    struct rdsv3_connection *conn = (struct rdsv3_connection *)data;

    (void) rdsv3_ib_recv_refill(conn, 0);
}

void
rdsv3_ib_tasklet_fn(void *data)
{
    struct rdsv3_ib_connection *ic = (struct rdsv3_ib_connection *)data;
    struct rdsv3_connection *conn = ic->conn;
    struct rdsv3_ib_ack_state ack_state = { 0, };
    ibt_wc_t wc[RDSV3_IB_WC_POLL_SIZE];
    uint_t polled;
    int i;

    RDSV3_DPRINTF4("rdsv3_ib_tasklet_fn",
        "Enter(conn: %p ic: %p)", conn, ic);

    rdsv3_ib_stats_inc(s_ib_tasklet_call);

    /*
     * Poll in a loop before and after enabling the next event
     */
    while (ibt_poll_cq(RDSV3_CQ2CQHDL(ic->i_cq), &wc[0],
        RDSV3_IB_WC_POLL_SIZE, &polled) == IBT_SUCCESS) {
        for (i = 0; i < polled; i++) {
            RDSV3_DPRINTF4("rdsv3_ib_tasklet_fn",
            "wc_id 0x%llx type %d status %u byte_len %u \
                imm_data %u\n",
                (unsigned long long)wc[i].wc_id, wc[i].wc_type,
                wc[i].wc_status, wc[i].wc_bytes_xfer,
                ntohl(wc[i].wc_immed_data));

            if (wc[i].wc_id & RDSV3_IB_SEND_OP) {
                rdsv3_ib_send_cqe_handler(ic, &wc[i]);
            } else {
                rdsv3_ib_recv_cqe_handler(ic, &wc[i],
                    &ack_state);
            }
        }
    }
    (void) ibt_enable_cq_notify(RDSV3_CQ2CQHDL(ic->i_cq),
        IBT_NEXT_SOLICITED);
    while (ibt_poll_cq(RDSV3_CQ2CQHDL(ic->i_cq), &wc[0],
        RDSV3_IB_WC_POLL_SIZE, &polled) == IBT_SUCCESS) {
        for (i = 0; i < polled; i++) {
            RDSV3_DPRINTF4("rdsv3_ib_tasklet_fn",
            "wc_id 0x%llx type %d status %u byte_len %u \
                imm_data %u\n",
                (unsigned long long)wc[i].wc_id, wc[i].wc_type,
                wc[i].wc_status, wc[i].wc_bytes_xfer,
                ntohl(wc[i].wc_immed_data));

            if (wc[i].wc_id & RDSV3_IB_SEND_OP) {
                rdsv3_ib_send_cqe_handler(ic, &wc[i]);
            } else {
                rdsv3_ib_recv_cqe_handler(ic, &wc[i],
                    &ack_state);
            }
        }
    }

    if (ack_state.ack_next_valid) {
        rdsv3_ib_set_ack(ic, ack_state.ack_next,
            ack_state.ack_required);
    }
    if (ack_state.ack_recv_valid && ack_state.ack_recv > ic->i_ack_recv) {
        rdsv3_send_drop_acked(conn, ack_state.ack_recv, NULL);
        ic->i_ack_recv = ack_state.ack_recv;
    }
    if (rdsv3_conn_up(conn)) {
        if (!test_bit(RDSV3_LL_SEND_FULL, &conn->c_flags))
            (void) rdsv3_send_xmit(ic->conn);
        rdsv3_ib_attempt_ack(ic);
    }
}

static void
rdsv3_ib_qp_event_handler(struct ib_event *event, void *data)
{
    struct rdsv3_connection *conn = data;
    struct rdsv3_ib_connection *ic = conn->c_transport_data;

    RDSV3_DPRINTF2("rdsv3_ib_qp_event_handler", "conn %p ic %p event %u",
        conn, ic, event->event);

    switch (event->event) {
    case IB_EVENT_COMM_EST:
        (void) rdma_notify(ic->i_cm_id, IB_EVENT_COMM_EST);
        break;
    default:
        if (conn) {
            RDSV3_DPRINTF2("rdsv3_ib_qp_event_handler",
                "RDS/IB: Fatal QP Event %u - "
                "connection %u.%u.%u.%u ->%u.%u.%u.%u "
                "...reconnecting",
                event->event, NIPQUAD(conn->c_laddr),
                NIPQUAD(conn->c_faddr));
            rdsv3_conn_drop(conn);
        } else {
            RDSV3_DPRINTF2("rdsv3_ib_qp_event_handler",
                "RDS/IB: Fatal QP Event %u - connection"
                "...reconnecting", event->event);
        }
        break;
    }

    RDSV3_DPRINTF2("rdsv3_ib_qp_event_handler", "Return conn: %p event: %p",
        conn, event);
}

extern int rdsv3_ib_alloc_hdrs(ib_device_t *dev,
    struct rdsv3_ib_connection *ic);
extern void rdsv3_ib_free_hdrs(ib_device_t *dev,
    struct rdsv3_ib_connection *ic);

/*
 * This needs to be very careful to not leave IS_ERR pointers around for
 * cleanup to trip over.
 */
static int
rdsv3_ib_setup_qp(struct rdsv3_connection *conn)
{
    struct rdsv3_ib_connection *ic = conn->c_transport_data;
    struct ib_device *dev = ic->i_cm_id->device;
    struct ib_qp_init_attr attr;
    struct rdsv3_ib_device *rds_ibdev;
    ibt_send_wr_t *wrp;
    ibt_wr_ds_t *sgl;
    int ret, i;

    RDSV3_DPRINTF2("rdsv3_ib_setup_qp", "Enter conn: %p", conn);

    /*
     * rdsv3_ib_add_one creates a rdsv3_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, &rdsv3_ib_client);
    if (!rds_ibdev) {
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "RDS/IB: No client_data for device %s", dev->name);
        return (-EOPNOTSUPP);
    }
    ic->rds_ibdev = rds_ibdev;

    if (rds_ibdev->max_wrs < ic->i_send_ring.w_nr + 1)
        rdsv3_ib_ring_resize(&ic->i_send_ring, rds_ibdev->max_wrs - 1);
    if (rds_ibdev->max_wrs < ic->i_recv_ring.w_nr + 1)
        rdsv3_ib_ring_resize(&ic->i_recv_ring, rds_ibdev->max_wrs - 1);

    /* Protection domain and memory range */
    ic->i_pd = rds_ibdev->pd;

    /*
     * IB_CQ_VECTOR_LEAST_ATTACHED and/or the corresponding feature is
     * not implmeneted in Hermon yet, but we can pass it to ib_create_cq()
     * anyway.
     */
    ic->i_cq = ib_create_cq(dev, rdsv3_ib_cq_comp_handler,
        rdsv3_ib_cq_event_handler, conn,
        ic->i_recv_ring.w_nr + ic->i_send_ring.w_nr + 1,
        rdsv3_af_grp_get_sched(ic->rds_ibdev->aft_hcagp));
    if (IS_ERR(ic->i_cq)) {
        ret = PTR_ERR(ic->i_cq);
        ic->i_cq = NULL;
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "ib_create_cq failed: %d", ret);
        goto out;
    }
    if (rdsv3_enable_snd_cq) {
        ic->i_snd_cq = ib_create_cq(dev, rdsv3_ib_snd_cq_comp_handler,
            rdsv3_ib_cq_event_handler, conn, ic->i_send_ring.w_nr + 1,
            rdsv3_af_grp_get_sched(ic->rds_ibdev->aft_hcagp));
        if (IS_ERR(ic->i_snd_cq)) {
            ret = PTR_ERR(ic->i_snd_cq);
            (void) ib_destroy_cq(ic->i_cq);
            ic->i_cq = NULL;
            ic->i_snd_cq = NULL;
            RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
                "ib_create_cq send cq failed: %d", ret);
            goto out;
        }
    }

    /* XXX negotiate max send/recv with remote? */
    (void) memset(&attr, 0, sizeof (attr));
    attr.event_handler = rdsv3_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 = RDSV3_IB_RECV_SGE;
    attr.sq_sig_type = IB_SIGNAL_REQ_WR;
    attr.qp_type = IB_QPT_RC;
    if (rdsv3_enable_snd_cq) {
        attr.send_cq = ic->i_snd_cq;
    } else {
        attr.send_cq = ic->i_cq;
    }
    attr.recv_cq = ic->i_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) {
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "rdma_create_qp failed: %d", ret);
        goto out;
    }

    ret = rdsv3_ib_alloc_hdrs(dev, ic);
    if (ret != 0) {
        ret = -ENOMEM;
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "rdsv3_ib_alloc_hdrs failed: %d", ret);
        goto out;
    }

    ic->i_sends = kmem_alloc(ic->i_send_ring.w_nr *
        sizeof (struct rdsv3_ib_send_work), KM_NOSLEEP);
    if (ic->i_sends == NULL) {
        ret = -ENOMEM;
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "send allocation failed: %d", ret);
        goto out;
    }
    (void) memset(ic->i_sends, 0, ic->i_send_ring.w_nr *
        sizeof (struct rdsv3_ib_send_work));

    ic->i_send_wrs =
        kmem_alloc(ic->i_send_ring.w_nr * (sizeof (ibt_send_wr_t) +
        RDSV3_IB_MAX_SGE * sizeof (ibt_wr_ds_t)), KM_NOSLEEP);
    if (ic->i_send_wrs == NULL) {
        ret = -ENOMEM;
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "Send WR allocation failed: %d", ret);
        goto out;
    }
    sgl = (ibt_wr_ds_t *)((uint8_t *)ic->i_send_wrs +
        (ic->i_send_ring.w_nr * sizeof (ibt_send_wr_t)));
    for (i = 0; i < ic->i_send_ring.w_nr; i++) {
        wrp = &ic->i_send_wrs[i];
        wrp->wr_sgl = &sgl[i * RDSV3_IB_MAX_SGE];
    }

    ic->i_recvs = kmem_alloc(ic->i_recv_ring.w_nr *
        sizeof (struct rdsv3_ib_recv_work), KM_NOSLEEP);
    if (ic->i_recvs == NULL) {
        ret = -ENOMEM;
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "recv allocation failed: %d", ret);
        goto out;
    }
    (void) memset(ic->i_recvs, 0, ic->i_recv_ring.w_nr *
        sizeof (struct rdsv3_ib_recv_work));

    ic->i_recv_wrs =
        kmem_alloc(ic->i_recv_ring.w_nr * sizeof (ibt_recv_wr_t),
        KM_NOSLEEP);
    if (ic->i_recv_wrs == NULL) {
        ret = -ENOMEM;
        RDSV3_DPRINTF2("rdsv3_ib_setup_qp",
            "Recv WR allocation failed: %d", ret);
        goto out;
    }

    rdsv3_ib_recv_init_ack(ic);

    RDSV3_DPRINTF2("rdsv3_ib_setup_qp", "conn %p pd %p mr %p cq %p",
        conn, ic->i_pd, ic->i_mr, ic->i_cq);

out:
    return (ret);
}

static uint32_t
rdsv3_ib_protocol_compatible(struct rdma_cm_event *event)
{
    const struct rdsv3_ib_connect_private *dp =
        event->param.conn.private_data;
    uint16_t common;
    uint32_t version = 0;

    RDSV3_DPRINTF2("rdsv3_ib_protocol_compatible", "Enter event: %p",
        event);

    /*
     * 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) {
        RDSV3_DPRINTF2("rdsv3_ib_protocol_compatible",
            "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 = ntohs(dp->dp_protocol_minor_mask) &
        RDSV3_IB_SUPPORTED_PROTOCOLS;
    if (dp->dp_protocol_major == 3 && common) {
        version = RDS_PROTOCOL_3_0;
        while ((common >>= 1) != 0)
            version++;
    } else {
        RDSV3_DPRINTF2("rdsv3_ib_protocol_compatible",
            "RDS: Connection from %u.%u.%u.%u using "
            "incompatible protocol version %u.%u\n",
            NIPQUAD(dp->dp_saddr),
            dp->dp_protocol_major,
            dp->dp_protocol_minor);
    }

    RDSV3_DPRINTF2("rdsv3_ib_protocol_compatible", "Return event: %p",
        event);

    return (version);
}

int
rdsv3_ib_cm_handle_connect(struct rdma_cm_id *cm_id,
    struct rdma_cm_event *event)
{
    uint64_be_t lguid = cm_id->route.path_rec->sgid.global.interface_id;
    uint64_be_t fguid = cm_id->route.path_rec->dgid.global.interface_id;
    const struct rdsv3_ib_connect_private *dp =
        event->param.conn.private_data;
    struct rdsv3_ib_connect_private dp_rep;
    struct rdsv3_connection *conn = NULL;
    struct rdsv3_ib_connection *ic = NULL;
    struct rdma_conn_param conn_param;
    uint32_t version;
    int err, destroy = 1;
    boolean_t conn_created = B_FALSE;

    RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
        "Enter cm_id: %p event: %p", cm_id, event);

    /* Check whether the remote protocol version matches ours. */
    version = rdsv3_ib_protocol_compatible(event);
    if (!version) {
        RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
            "version mismatch");
        goto out;
    }

    RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
        "saddr %u.%u.%u.%u daddr %u.%u.%u.%u RDSv%d.%d lguid 0x%llx fguid "
        "0x%llx", NIPQUAD(dp->dp_saddr), NIPQUAD(dp->dp_daddr),
        RDS_PROTOCOL_MAJOR(version), RDS_PROTOCOL_MINOR(version),
        (unsigned long long)ntohll(lguid),
        (unsigned long long)ntohll(fguid));

    conn = rdsv3_conn_create(dp->dp_daddr, dp->dp_saddr,
        &rdsv3_ib_transport, KM_NOSLEEP);
    if (IS_ERR(conn)) {
        RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
            "rdsv3_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 rdsv3_queue_reconnect()
     */
    mutex_enter(&conn->c_cm_lock);
    if (!rdsv3_conn_transition(conn, RDSV3_CONN_DOWN,
        RDSV3_CONN_CONNECTING)) {
        if (rdsv3_conn_state(conn) == RDSV3_CONN_UP) {
            RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
                "incoming connect when connected: %p",
                conn);
            rdsv3_conn_drop(conn);
            rdsv3_ib_stats_inc(s_ib_listen_closed_stale);
            mutex_exit(&conn->c_cm_lock);
            goto out;
        } else if (rdsv3_conn_state(conn) == RDSV3_CONN_CONNECTING) {
            /* Wait and see - our connect may still be succeeding */
            RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
                "peer-to-peer connection request: %p, "
                "lguid: 0x%llx fguid: 0x%llx",
                conn, lguid, fguid);
            rdsv3_ib_stats_inc(s_ib_connect_raced);
        }
        mutex_exit(&conn->c_cm_lock);
        goto out;
    }

    ic = conn->c_transport_data;

    rdsv3_ib_set_protocol(conn, version);
    rdsv3_ib_set_flow_control(conn, ntohl(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)
        rdsv3_send_drop_acked(conn, ntohll(dp->dp_ack_seq), NULL);

    ASSERT(!cm_id->context);
    ASSERT(!ic->i_cm_id);

    if (ic->i_cm_id != NULL)
        RDSV3_PANIC();

    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 = rdsv3_ib_setup_qp(conn);
    if (err) {
        RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
            "rdsv3_ib_setup_qp failed (%d)", err);
        mutex_exit(&conn->c_cm_lock);
        rdsv3_conn_drop(conn);
        goto out;
    }

    rdsv3_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);
    mutex_exit(&conn->c_cm_lock);
    if (err) {
        RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
            "rdma_accept failed (%d)", err);
        rdsv3_conn_drop(conn);
        goto out;
    }

    RDSV3_DPRINTF2("rdsv3_ib_cm_handle_connect",
        "Return cm_id: %p event: %p", cm_id, event);

    return (0);

out:
    (void) rdma_reject(cm_id, NULL, 0);
    return (destroy);
}


int
rdsv3_ib_cm_initiate_connect(struct rdma_cm_id *cm_id)
{
    struct rdsv3_connection *conn = cm_id->context;
    struct rdsv3_ib_connection *ic = conn->c_transport_data;
    struct rdma_conn_param conn_param;
    struct rdsv3_ib_connect_private dp;
    int ret;

    RDSV3_DPRINTF2("rdsv3_ib_cm_initiate_connect", "Enter: cm_id: %p",
        cm_id);

    /*
     * If the peer doesn't do protocol negotiation, we must
     * default to RDSv3.0
     */
    rdsv3_ib_set_protocol(conn, RDS_PROTOCOL_3_0);
    ic->i_flowctl =
        rdsv3_ib_sysctl_flow_control;   /* advertise flow control */

    ret = rdsv3_ib_setup_qp(conn);
    if (ret) {
        RDSV3_DPRINTF2("rdsv3_ib_cm_initiate_connect",
            "rdsv3_ib_setup_qp failed (%d)", ret);
        rdsv3_conn_drop(conn);
        goto out;
    }

    rdsv3_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) {
        RDSV3_DPRINTF2("rdsv3_ib_cm_initiate_connect",
            "rdma_connect failed (%d)", ret);
        rdsv3_conn_drop(conn);
    }

    RDSV3_DPRINTF2("rdsv3_ib_cm_initiate_connect",
        "Return: cm_id: %p", cm_id);

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
rdsv3_ib_conn_connect(struct rdsv3_connection *conn)
{
    struct rdsv3_ib_connection *ic = conn->c_transport_data;
    struct sockaddr_in src, dest;
    ipaddr_t    laddr, faddr;
    int ret;

    RDSV3_DPRINTF2("rdsv3_ib_conn_connect", "Enter: conn: %p", conn);

    /*
     * XXX I wonder what affect the port space has
     */
    /* delegate cm event handler to rdma_transport */
    ic->i_cm_id = rdma_create_id(rdsv3_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;
        RDSV3_DPRINTF2("rdsv3_ib_conn_connect",
            "rdma_create_id() failed: %d", ret);
        goto out;
    }

    RDSV3_DPRINTF3("rdsv3_ib_conn_connect",
        "created cm id %p for conn %p", ic->i_cm_id, conn);

    /* The ipaddr should be in the network order */
    laddr = conn->c_laddr;
    faddr = conn->c_faddr;
    ret = rdsv3_sc_path_lookup(&laddr, &faddr);
    if (ret == 0) {
        RDSV3_DPRINTF2(LABEL, "Path not found (0x%x 0x%x)",
            ntohl(laddr), ntohl(faddr));
    }

    src.sin_family = AF_INET;
    src.sin_addr.s_addr = (uint32_t)laddr;
    src.sin_port = (uint16_t)htons(0);

    dest.sin_family = AF_INET;
    dest.sin_addr.s_addr = (uint32_t)faddr;
    dest.sin_port = (uint16_t)htons(RDSV3_PORT);

    ret = rdma_resolve_addr(ic->i_cm_id, (struct sockaddr *)&src,
        (struct sockaddr *)&dest,
        RDSV3_RDMA_RESOLVE_TIMEOUT_MS);
    if (ret) {
        RDSV3_DPRINTF2("rdsv3_ib_conn_connect",
            "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;
    }

    RDSV3_DPRINTF2("rdsv3_ib_conn_connect", "Return: conn: %p", conn);

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
rdsv3_ib_conn_shutdown(struct rdsv3_connection *conn)
{
    struct rdsv3_ib_connection *ic = conn->c_transport_data;
    int err = 0;

    RDSV3_DPRINTF2("rdsv3_ib_conn_shutdown",
        "cm %p pd %p cq %p qp %p", ic->i_cm_id,
        ic->i_pd, ic->i_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;

        RDSV3_DPRINTF2("rdsv3_ib_conn_shutdown",
            "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.
             */
            RDSV3_DPRINTF2("rdsv3_ib_conn_shutdown",
                "failed to disconnect, cm: %p err %d",
                ic->i_cm_id, err);
        }

        if (ic->i_cm_id->qp) {
            (void) ibt_flush_qp(
                ib_get_ibt_channel_hdl(ic->i_cm_id));
            /*
             * Don't wait for the send ring to be empty -- there
             * may be completed non-signaled entries sitting on
             * there. We unmap these below.
             */
            rdsv3_wait_event(&ic->i_recv_ring.w_empty_wait,
                rdsv3_ib_ring_empty(&ic->i_recv_ring));
            /*
             * Note that Linux original code calls
             * rdma_destroy_qp() after rdsv3_ib_recv_clear_ring(ic).
             */
            rdma_destroy_qp(ic->i_cm_id);
        }

        if (rdsv3_enable_snd_cq) {
            if (ic->i_snd_soft_cq) {
                rdsv3_af_thr_destroy(ic->i_snd_soft_cq);
                ic->i_snd_soft_cq = NULL;
            }
            if (ic->i_snd_cq)
                (void) ib_destroy_cq(ic->i_snd_cq);
        }
        if (ic->i_soft_cq) {
            rdsv3_af_thr_destroy(ic->i_soft_cq);
            ic->i_soft_cq = NULL;
        }
        if (ic->i_refill_rq) {
            rdsv3_af_thr_destroy(ic->i_refill_rq);
            ic->i_refill_rq = NULL;
        }
        if (ic->i_cq)
            (void) ib_destroy_cq(ic->i_cq);

        if (ic->i_mr)
            rdsv3_ib_free_hdrs(dev, ic);

        if (ic->i_sends)
            rdsv3_ib_send_clear_ring(ic);
        if (ic->i_recvs)
            rdsv3_ib_recv_clear_ring(ic);

        rdma_destroy_id(ic->i_cm_id);

        /*
         * Move connection back to the nodev list.
         */
        if (ic->i_on_dev_list)
            rdsv3_ib_remove_conn(ic->rds_ibdev, conn);

        ic->i_cm_id = NULL;
        ic->i_pd = NULL;
        ic->i_mr = NULL;
        ic->i_cq = NULL;
        ic->i_snd_cq = NULL;
        ic->i_send_hdrs = NULL;
        ic->i_recv_hdrs = NULL;
        ic->i_ack = NULL;
    }
    ASSERT(!ic->i_on_dev_list);

    /* Clear pending transmit */
    if (ic->i_rm) {
        rdsv3_message_put(ic->i_rm);
        ic->i_rm = NULL;
    }

    /* Clear the ACK state */
    clear_bit(IB_ACK_IN_FLIGHT, &ic->i_ack_flags);
    ic->i_ack_next = 0;
    ic->i_ack_recv = 0;

    /* Clear flow control state */
    ic->i_flowctl = 0;
    ic->i_credits = 0;

    rdsv3_ib_ring_init(&ic->i_send_ring, rdsv3_ib_sysctl_max_send_wr);
    rdsv3_ib_ring_init(&ic->i_recv_ring, rdsv3_ib_sysctl_max_recv_wr);

    if (ic->i_ibinc) {
        rdsv3_inc_put(&ic->i_ibinc->ii_inc);
        ic->i_ibinc = NULL;
    }

    if (ic->i_sends) {
        kmem_free(ic->i_sends,
            ic->i_send_ring.w_nr * sizeof (struct rdsv3_ib_send_work));
        ic->i_sends = NULL;
    }
    if (ic->i_send_wrs) {
        kmem_free(ic->i_send_wrs, ic->i_send_ring.w_nr *
            (sizeof (ibt_send_wr_t) +
            RDSV3_IB_MAX_SGE * sizeof (ibt_wr_ds_t)));
        ic->i_send_wrs = NULL;
    }
    if (ic->i_recvs) {
        kmem_free(ic->i_recvs,
            ic->i_recv_ring.w_nr * sizeof (struct rdsv3_ib_recv_work));
        ic->i_recvs = NULL;
    }
    if (ic->i_recv_wrs) {
        kmem_free(ic->i_recv_wrs, ic->i_recv_ring.w_nr *
            (sizeof (ibt_recv_wr_t)));
        ic->i_recv_wrs = NULL;
    }

    RDSV3_DPRINTF2("rdsv3_ib_conn_shutdown", "Return conn: %p", conn);
}

/* ARGSUSED */
int
rdsv3_ib_conn_alloc(struct rdsv3_connection *conn, int gfp)
{
    struct rdsv3_ib_connection *ic;

    RDSV3_DPRINTF2("rdsv3_ib_conn_alloc", "conn: %p", conn);

    /* XXX too lazy? */
    ic = kmem_zalloc(sizeof (struct rdsv3_ib_connection), gfp);
    if (!ic)
        return (-ENOMEM);

    list_link_init(&ic->ib_node);

    mutex_init(&ic->i_recv_mutex, NULL, MUTEX_DRIVER, NULL);
    mutex_init(&ic->i_ack_lock, NULL, MUTEX_DRIVER, NULL);

    /*
     * rdsv3_ib_conn_shutdown() waits for these to be emptied so they
     * must be initialized before it can be called.
     */
    rdsv3_ib_ring_init(&ic->i_send_ring, rdsv3_ib_sysctl_max_send_wr);
    rdsv3_ib_ring_init(&ic->i_recv_ring, rdsv3_ib_sysctl_max_recv_wr);

    ic->conn = conn;
    conn->c_transport_data = ic;

    mutex_enter(&ib_nodev_conns_lock);
    list_insert_tail(&ib_nodev_conns, ic);
    mutex_exit(&ib_nodev_conns_lock);

    RDSV3_DPRINTF2("rdsv3_ib_conn_alloc", "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
rdsv3_ib_conn_free(void *arg)
{
    struct rdsv3_ib_connection *ic = arg;
    kmutex_t    *lock_ptr;

    RDSV3_DPRINTF2("rdsv3_ib_conn_free", "ic %p\n", ic);

#ifndef __lock_lint
    /*
     * 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->i_on_dev_list ?
        &ic->rds_ibdev->spinlock : &ib_nodev_conns_lock;

    mutex_enter(lock_ptr);
    list_remove_node(&ic->ib_node);
    mutex_exit(lock_ptr);
#endif
    kmem_free(ic, sizeof (*ic));
}

/*
 * An error occurred on the connection
 */
void
__rdsv3_ib_conn_error(struct rdsv3_connection *conn)
{
    rdsv3_conn_drop(conn);
}