/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.gnu.org/licenses/gpl-2.0.html
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, 2015, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * lnet/klnds/o2iblnd/o2iblnd_cb.c
 *
 * Author: Eric Barton <eric@bartonsoftware.com>
 */

#include "o2iblnd.h"

#define MAX_CONN_RACES_BEFORE_ABORT 20

static void kiblnd_peer_alive(struct kib_peer *peer);
static void kiblnd_peer_connect_failed(struct kib_peer *peer, int active, int error);
static void kiblnd_init_tx_msg(lnet_ni_t *ni, struct kib_tx *tx,
                               int type, int body_nob);
static int kiblnd_init_rdma(struct kib_conn *conn, struct kib_tx *tx, int type,
                            int resid, struct kib_rdma_desc *dstrd,
                            __u64 dstcookie);
static void kiblnd_queue_tx_locked(struct kib_tx *tx, struct kib_conn *conn);
static void kiblnd_queue_tx(struct kib_tx *tx, struct kib_conn *conn);
static void kiblnd_unmap_tx(lnet_ni_t *ni, struct kib_tx *tx);
static void kiblnd_check_sends_locked(struct kib_conn *conn);

static void
kiblnd_tx_done(lnet_ni_t *ni, struct kib_tx *tx)
{
        lnet_msg_t *lntmsg[2];
        struct kib_net *net = ni->ni_data;
        int rc;
        int i;

        LASSERT(net);
        LASSERT(!in_interrupt());
        LASSERT(!tx->tx_queued);               /* mustn't be queued for sending */
        LASSERT(!tx->tx_sending);         /* mustn't be awaiting sent callback */
        LASSERT(!tx->tx_waiting);             /* mustn't be awaiting peer response */
        LASSERT(tx->tx_pool);

        kiblnd_unmap_tx(ni, tx);

        /* tx may have up to 2 lnet msgs to finalise */
        lntmsg[0] = tx->tx_lntmsg[0]; tx->tx_lntmsg[0] = NULL;
        lntmsg[1] = tx->tx_lntmsg[1]; tx->tx_lntmsg[1] = NULL;
        rc = tx->tx_status;

        if (tx->tx_conn) {
                LASSERT(ni == tx->tx_conn->ibc_peer->ibp_ni);

                kiblnd_conn_decref(tx->tx_conn);
                tx->tx_conn = NULL;
        }

        tx->tx_nwrq = 0;
        tx->tx_status = 0;

        kiblnd_pool_free_node(&tx->tx_pool->tpo_pool, &tx->tx_list);

        /* delay finalize until my descs have been freed */
        for (i = 0; i < 2; i++) {
                if (!lntmsg[i])
                        continue;

                lnet_finalize(ni, lntmsg[i], rc);
        }
}

void
kiblnd_txlist_done(lnet_ni_t *ni, struct list_head *txlist, int status)
{
        struct kib_tx *tx;

        while (!list_empty(txlist)) {
                tx = list_entry(txlist->next, struct kib_tx, tx_list);

                list_del(&tx->tx_list);
                /* complete now */
                tx->tx_waiting = 0;
                tx->tx_status = status;
                kiblnd_tx_done(ni, tx);
        }
}

static struct kib_tx *
kiblnd_get_idle_tx(lnet_ni_t *ni, lnet_nid_t target)
{
        struct kib_net *net = (struct kib_net *)ni->ni_data;
        struct list_head *node;
        struct kib_tx *tx;
        struct kib_tx_poolset *tps;

        tps = net->ibn_tx_ps[lnet_cpt_of_nid(target)];
        node = kiblnd_pool_alloc_node(&tps->tps_poolset);
        if (!node)
                return NULL;
        tx = list_entry(node, struct kib_tx, tx_list);

        LASSERT(!tx->tx_nwrq);
        LASSERT(!tx->tx_queued);
        LASSERT(!tx->tx_sending);
        LASSERT(!tx->tx_waiting);
        LASSERT(!tx->tx_status);
        LASSERT(!tx->tx_conn);
        LASSERT(!tx->tx_lntmsg[0]);
        LASSERT(!tx->tx_lntmsg[1]);
        LASSERT(!tx->tx_nfrags);

        return tx;
}

static void
kiblnd_drop_rx(struct kib_rx *rx)
{
        struct kib_conn *conn = rx->rx_conn;
        struct kib_sched_info *sched = conn->ibc_sched;
        unsigned long flags;

        spin_lock_irqsave(&sched->ibs_lock, flags);
        LASSERT(conn->ibc_nrx > 0);
        conn->ibc_nrx--;
        spin_unlock_irqrestore(&sched->ibs_lock, flags);

        kiblnd_conn_decref(conn);
}

int
kiblnd_post_rx(struct kib_rx *rx, int credit)
{
        struct kib_conn *conn = rx->rx_conn;
        struct kib_net *net = conn->ibc_peer->ibp_ni->ni_data;
        struct ib_recv_wr *bad_wrq = NULL;
        struct ib_mr *mr = conn->ibc_hdev->ibh_mrs;
        int rc;

        LASSERT(net);
        LASSERT(!in_interrupt());
        LASSERT(credit == IBLND_POSTRX_NO_CREDIT ||
                credit == IBLND_POSTRX_PEER_CREDIT ||
                credit == IBLND_POSTRX_RSRVD_CREDIT);
        LASSERT(mr);

        rx->rx_sge.lkey   = mr->lkey;
        rx->rx_sge.addr   = rx->rx_msgaddr;
        rx->rx_sge.length = IBLND_MSG_SIZE;

        rx->rx_wrq.next    = NULL;
        rx->rx_wrq.sg_list = &rx->rx_sge;
        rx->rx_wrq.num_sge = 1;
        rx->rx_wrq.wr_id   = kiblnd_ptr2wreqid(rx, IBLND_WID_RX);

        LASSERT(conn->ibc_state >= IBLND_CONN_INIT);
        LASSERT(rx->rx_nob >= 0);             /* not posted */

        if (conn->ibc_state > IBLND_CONN_ESTABLISHED) {
                kiblnd_drop_rx(rx);          /* No more posts for this rx */
                return 0;
        }

        rx->rx_nob = -1;                        /* flag posted */

        /* NB: need an extra reference after ib_post_recv because we don't
         * own this rx (and rx::rx_conn) anymore, LU-5678.
         */
        kiblnd_conn_addref(conn);
        rc = ib_post_recv(conn->ibc_cmid->qp, &rx->rx_wrq, &bad_wrq);
        if (unlikely(rc)) {
                CERROR("Can't post rx for %s: %d, bad_wrq: %p\n",
                       libcfs_nid2str(conn->ibc_peer->ibp_nid), rc, bad_wrq);
                rx->rx_nob = 0;
        }

        if (conn->ibc_state < IBLND_CONN_ESTABLISHED) /* Initial post */
                goto out;

        if (unlikely(rc)) {
                kiblnd_close_conn(conn, rc);
                kiblnd_drop_rx(rx);          /* No more posts for this rx */
                goto out;
        }

        if (credit == IBLND_POSTRX_NO_CREDIT)
                goto out;

        spin_lock(&conn->ibc_lock);
        if (credit == IBLND_POSTRX_PEER_CREDIT)
                conn->ibc_outstanding_credits++;
        else
                conn->ibc_reserved_credits++;
        kiblnd_check_sends_locked(conn);
        spin_unlock(&conn->ibc_lock);

out:
        kiblnd_conn_decref(conn);
        return rc;
}

static struct kib_tx *
kiblnd_find_waiting_tx_locked(struct kib_conn *conn, int txtype, __u64 cookie)
{
        struct list_head *tmp;

        list_for_each(tmp, &conn->ibc_active_txs) {
                struct kib_tx *tx = list_entry(tmp, struct kib_tx, tx_list);

                LASSERT(!tx->tx_queued);
                LASSERT(tx->tx_sending || tx->tx_waiting);

                if (tx->tx_cookie != cookie)
                        continue;

                if (tx->tx_waiting &&
                    tx->tx_msg->ibm_type == txtype)
                        return tx;

                CWARN("Bad completion: %swaiting, type %x (wanted %x)\n",
                      tx->tx_waiting ? "" : "NOT ",
                      tx->tx_msg->ibm_type, txtype);
        }
        return NULL;
}

static void
kiblnd_handle_completion(struct kib_conn *conn, int txtype, int status, __u64 cookie)
{
        struct kib_tx *tx;
        lnet_ni_t *ni = conn->ibc_peer->ibp_ni;
        int idle;

        spin_lock(&conn->ibc_lock);

        tx = kiblnd_find_waiting_tx_locked(conn, txtype, cookie);
        if (!tx) {
                spin_unlock(&conn->ibc_lock);

                CWARN("Unmatched completion type %x cookie %#llx from %s\n",
                      txtype, cookie, libcfs_nid2str(conn->ibc_peer->ibp_nid));
                kiblnd_close_conn(conn, -EPROTO);
                return;
        }

        if (!tx->tx_status) {          /* success so far */
                if (status < 0) /* failed? */
                        tx->tx_status = status;
                else if (txtype == IBLND_MSG_GET_REQ)
                        lnet_set_reply_msg_len(ni, tx->tx_lntmsg[1], status);
        }

        tx->tx_waiting = 0;

        idle = !tx->tx_queued && !tx->tx_sending;
        if (idle)
                list_del(&tx->tx_list);

        spin_unlock(&conn->ibc_lock);

        if (idle)
                kiblnd_tx_done(ni, tx);
}

static void
kiblnd_send_completion(struct kib_conn *conn, int type, int status, __u64 cookie)
{
        lnet_ni_t *ni = conn->ibc_peer->ibp_ni;
        struct kib_tx *tx = kiblnd_get_idle_tx(ni, conn->ibc_peer->ibp_nid);

        if (!tx) {
                CERROR("Can't get tx for completion %x for %s\n",
                       type, libcfs_nid2str(conn->ibc_peer->ibp_nid));
                return;
        }

        tx->tx_msg->ibm_u.completion.ibcm_status = status;
        tx->tx_msg->ibm_u.completion.ibcm_cookie = cookie;
        kiblnd_init_tx_msg(ni, tx, type, sizeof(struct kib_completion_msg));

        kiblnd_queue_tx(tx, conn);
}

static void
kiblnd_handle_rx(struct kib_rx *rx)
{
        struct kib_msg *msg = rx->rx_msg;
        struct kib_conn *conn = rx->rx_conn;
        lnet_ni_t *ni = conn->ibc_peer->ibp_ni;
        int credits = msg->ibm_credits;
        struct kib_tx *tx;
        int rc = 0;
        int rc2;
        int post_credit;

        LASSERT(conn->ibc_state >= IBLND_CONN_ESTABLISHED);

        CDEBUG(D_NET, "Received %x[%d] from %s\n",
               msg->ibm_type, credits,
               libcfs_nid2str(conn->ibc_peer->ibp_nid));

        if (credits) {
                /* Have I received credits that will let me send? */
                spin_lock(&conn->ibc_lock);

                if (conn->ibc_credits + credits >
                    conn->ibc_queue_depth) {
                        rc2 = conn->ibc_credits;
                        spin_unlock(&conn->ibc_lock);

                        CERROR("Bad credits from %s: %d + %d > %d\n",
                               libcfs_nid2str(conn->ibc_peer->ibp_nid),
                               rc2, credits, conn->ibc_queue_depth);

                        kiblnd_close_conn(conn, -EPROTO);
                        kiblnd_post_rx(rx, IBLND_POSTRX_NO_CREDIT);
                        return;
                }

                conn->ibc_credits += credits;

                /* This ensures the credit taken by NOOP can be returned */
                if (msg->ibm_type == IBLND_MSG_NOOP &&
                    !IBLND_OOB_CAPABLE(conn->ibc_version)) /* v1 only */
                        conn->ibc_outstanding_credits++;

                kiblnd_check_sends_locked(conn);
                spin_unlock(&conn->ibc_lock);
        }

        switch (msg->ibm_type) {
        default:
                CERROR("Bad IBLND message type %x from %s\n",
                       msg->ibm_type, libcfs_nid2str(conn->ibc_peer->ibp_nid));
                post_credit = IBLND_POSTRX_NO_CREDIT;
                rc = -EPROTO;
                break;

        case IBLND_MSG_NOOP:
                if (IBLND_OOB_CAPABLE(conn->ibc_version)) {
                        post_credit = IBLND_POSTRX_NO_CREDIT;
                        break;
                }

                if (credits) /* credit already posted */
                        post_credit = IBLND_POSTRX_NO_CREDIT;
                else          /* a keepalive NOOP */
                        post_credit = IBLND_POSTRX_PEER_CREDIT;
                break;

        case IBLND_MSG_IMMEDIATE:
                post_credit = IBLND_POSTRX_DONT_POST;
                rc = lnet_parse(ni, &msg->ibm_u.immediate.ibim_hdr,
                                msg->ibm_srcnid, rx, 0);
                if (rc < 0)                  /* repost on error */
                        post_credit = IBLND_POSTRX_PEER_CREDIT;
                break;

        case IBLND_MSG_PUT_REQ:
                post_credit = IBLND_POSTRX_DONT_POST;
                rc = lnet_parse(ni, &msg->ibm_u.putreq.ibprm_hdr,
                                msg->ibm_srcnid, rx, 1);
                if (rc < 0)                  /* repost on error */
                        post_credit = IBLND_POSTRX_PEER_CREDIT;
                break;

        case IBLND_MSG_PUT_NAK:
                CWARN("PUT_NACK from %s\n",
                      libcfs_nid2str(conn->ibc_peer->ibp_nid));
                post_credit = IBLND_POSTRX_RSRVD_CREDIT;
                kiblnd_handle_completion(conn, IBLND_MSG_PUT_REQ,
                                         msg->ibm_u.completion.ibcm_status,
                                         msg->ibm_u.completion.ibcm_cookie);
                break;

        case IBLND_MSG_PUT_ACK:
                post_credit = IBLND_POSTRX_RSRVD_CREDIT;

                spin_lock(&conn->ibc_lock);
                tx = kiblnd_find_waiting_tx_locked(conn, IBLND_MSG_PUT_REQ,
                                                   msg->ibm_u.putack.ibpam_src_cookie);
                if (tx)
                        list_del(&tx->tx_list);
                spin_unlock(&conn->ibc_lock);

                if (!tx) {
                        CERROR("Unmatched PUT_ACK from %s\n",
                               libcfs_nid2str(conn->ibc_peer->ibp_nid));
                        rc = -EPROTO;
                        break;
                }

                LASSERT(tx->tx_waiting);
                /*
                 * CAVEAT EMPTOR: I could be racing with tx_complete, but...
                 * (a) I can overwrite tx_msg since my peer has received it!
                 * (b) tx_waiting set tells tx_complete() it's not done.
                 */
                tx->tx_nwrq = 0;                /* overwrite PUT_REQ */

                rc2 = kiblnd_init_rdma(conn, tx, IBLND_MSG_PUT_DONE,
                                       kiblnd_rd_size(&msg->ibm_u.putack.ibpam_rd),
                                       &msg->ibm_u.putack.ibpam_rd,
                                       msg->ibm_u.putack.ibpam_dst_cookie);
                if (rc2 < 0)
                        CERROR("Can't setup rdma for PUT to %s: %d\n",
                               libcfs_nid2str(conn->ibc_peer->ibp_nid), rc2);

                spin_lock(&conn->ibc_lock);
                tx->tx_waiting = 0;     /* clear waiting and queue atomically */
                kiblnd_queue_tx_locked(tx, conn);
                spin_unlock(&conn->ibc_lock);
                break;

        case IBLND_MSG_PUT_DONE:
                post_credit = IBLND_POSTRX_PEER_CREDIT;
                kiblnd_handle_completion(conn, IBLND_MSG_PUT_ACK,
                                         msg->ibm_u.completion.ibcm_status,
                                         msg->ibm_u.completion.ibcm_cookie);
                break;

        case IBLND_MSG_GET_REQ:
                post_credit = IBLND_POSTRX_DONT_POST;
                rc = lnet_parse(ni, &msg->ibm_u.get.ibgm_hdr,
                                msg->ibm_srcnid, rx, 1);
                if (rc < 0)                  /* repost on error */
                        post_credit = IBLND_POSTRX_PEER_CREDIT;
                break;

        case IBLND_MSG_GET_DONE:
                post_credit = IBLND_POSTRX_RSRVD_CREDIT;
                kiblnd_handle_completion(conn, IBLND_MSG_GET_REQ,
                                         msg->ibm_u.completion.ibcm_status,
                                         msg->ibm_u.completion.ibcm_cookie);
                break;
        }

        if (rc < 0)                          /* protocol error */
                kiblnd_close_conn(conn, rc);

        if (post_credit != IBLND_POSTRX_DONT_POST)
                kiblnd_post_rx(rx, post_credit);
}

static void
kiblnd_rx_complete(struct kib_rx *rx, int status, int nob)
{
        struct kib_msg *msg = rx->rx_msg;
        struct kib_conn *conn = rx->rx_conn;
        lnet_ni_t *ni = conn->ibc_peer->ibp_ni;
        struct kib_net *net = ni->ni_data;
        int rc;
        int err = -EIO;

        LASSERT(net);
        LASSERT(rx->rx_nob < 0);               /* was posted */
        rx->rx_nob = 0;                  /* isn't now */

        if (conn->ibc_state > IBLND_CONN_ESTABLISHED)
                goto ignore;

        if (status != IB_WC_SUCCESS) {
                CNETERR("Rx from %s failed: %d\n",
                        libcfs_nid2str(conn->ibc_peer->ibp_nid), status);
                goto failed;
        }

        LASSERT(nob >= 0);
        rx->rx_nob = nob;

        rc = kiblnd_unpack_msg(msg, rx->rx_nob);
        if (rc) {
                CERROR("Error %d unpacking rx from %s\n",
                       rc, libcfs_nid2str(conn->ibc_peer->ibp_nid));
                goto failed;
        }

        if (msg->ibm_srcnid != conn->ibc_peer->ibp_nid ||
            msg->ibm_dstnid != ni->ni_nid ||
            msg->ibm_srcstamp != conn->ibc_incarnation ||
            msg->ibm_dststamp != net->ibn_incarnation) {
                CERROR("Stale rx from %s\n",
                       libcfs_nid2str(conn->ibc_peer->ibp_nid));
                err = -ESTALE;
                goto failed;
        }

        /* set time last known alive */
        kiblnd_peer_alive(conn->ibc_peer);

        /* racing with connection establishment/teardown! */

        if (conn->ibc_state < IBLND_CONN_ESTABLISHED) {
                rwlock_t *g_lock = &kiblnd_data.kib_global_lock;
                unsigned long flags;

                write_lock_irqsave(g_lock, flags);
                /* must check holding global lock to eliminate race */
                if (conn->ibc_state < IBLND_CONN_ESTABLISHED) {
                        list_add_tail(&rx->rx_list, &conn->ibc_early_rxs);
                        write_unlock_irqrestore(g_lock, flags);
                        return;
                }
                write_unlock_irqrestore(g_lock, flags);
        }
        kiblnd_handle_rx(rx);
        return;

 failed:
        CDEBUG(D_NET, "rx %p conn %p\n", rx, conn);
        kiblnd_close_conn(conn, err);
 ignore:
        kiblnd_drop_rx(rx);                  /* Don't re-post rx. */
}

static struct page *
kiblnd_kvaddr_to_page(unsigned long vaddr)
{
        struct page *page;

        if (is_vmalloc_addr((void *)vaddr)) {
                page = vmalloc_to_page((void *)vaddr);
                LASSERT(page);
                return page;
        }
#ifdef CONFIG_HIGHMEM
        if (vaddr >= PKMAP_BASE &&
            vaddr < (PKMAP_BASE + LAST_PKMAP * PAGE_SIZE)) {
                /* No highmem pages only used for bulk (kiov) I/O */
                CERROR("find page for address in highmem\n");
                LBUG();
        }
#endif
        page = virt_to_page(vaddr);
        LASSERT(page);
        return page;
}

static int
kiblnd_fmr_map_tx(struct kib_net *net, struct kib_tx *tx, struct kib_rdma_desc *rd, __u32 nob)
{
        struct kib_hca_dev *hdev;
        struct kib_fmr_poolset *fps;
        int cpt;
        int rc;

        LASSERT(tx->tx_pool);
        LASSERT(tx->tx_pool->tpo_pool.po_owner);

        hdev = tx->tx_pool->tpo_hdev;
        cpt = tx->tx_pool->tpo_pool.po_owner->ps_cpt;

        fps = net->ibn_fmr_ps[cpt];
        rc = kiblnd_fmr_pool_map(fps, tx, rd, nob, 0, &tx->fmr);
        if (rc) {
                CERROR("Can't map %u bytes: %d\n", nob, rc);
                return rc;
        }

        /*
         * If rd is not tx_rd, it's going to get sent to a peer, who will need
         * the rkey
         */
        rd->rd_key = tx->fmr.fmr_key;
        rd->rd_frags[0].rf_addr &= ~hdev->ibh_page_mask;
        rd->rd_frags[0].rf_nob = nob;
        rd->rd_nfrags = 1;

        return 0;
}

static void kiblnd_unmap_tx(lnet_ni_t *ni, struct kib_tx *tx)
{
        struct kib_net *net = ni->ni_data;

        LASSERT(net);

        if (net->ibn_fmr_ps)
                kiblnd_fmr_pool_unmap(&tx->fmr, tx->tx_status);

        if (tx->tx_nfrags) {
                kiblnd_dma_unmap_sg(tx->tx_pool->tpo_hdev->ibh_ibdev,
                                    tx->tx_frags, tx->tx_nfrags, tx->tx_dmadir);
                tx->tx_nfrags = 0;
        }
}

static int kiblnd_map_tx(lnet_ni_t *ni, struct kib_tx *tx, struct kib_rdma_desc *rd,
                         int nfrags)
{
        struct kib_net *net = ni->ni_data;
        struct kib_hca_dev *hdev = net->ibn_dev->ibd_hdev;
        struct ib_mr *mr    = NULL;
        __u32 nob;
        int i;

        /*
         * If rd is not tx_rd, it's going to get sent to a peer and I'm the
         * RDMA sink
         */
        tx->tx_dmadir = (rd != tx->tx_rd) ? DMA_FROM_DEVICE : DMA_TO_DEVICE;
        tx->tx_nfrags = nfrags;

        rd->rd_nfrags = kiblnd_dma_map_sg(hdev->ibh_ibdev, tx->tx_frags,
                                          tx->tx_nfrags, tx->tx_dmadir);

        for (i = 0, nob = 0; i < rd->rd_nfrags; i++) {
                rd->rd_frags[i].rf_nob  = kiblnd_sg_dma_len(
                        hdev->ibh_ibdev, &tx->tx_frags[i]);
                rd->rd_frags[i].rf_addr = kiblnd_sg_dma_address(
                        hdev->ibh_ibdev, &tx->tx_frags[i]);
                nob += rd->rd_frags[i].rf_nob;
        }

        mr = kiblnd_find_rd_dma_mr(ni, rd, tx->tx_conn ?
                                   tx->tx_conn->ibc_max_frags : -1);
        if (mr) {
                /* found pre-mapping MR */
                rd->rd_key = (rd != tx->tx_rd) ? mr->rkey : mr->lkey;
                return 0;
        }

        if (net->ibn_fmr_ps)
                return kiblnd_fmr_map_tx(net, tx, rd, nob);

        return -EINVAL;
}

static int
kiblnd_setup_rd_iov(lnet_ni_t *ni, struct kib_tx *tx, struct kib_rdma_desc *rd,
                    unsigned int niov, const struct kvec *iov, int offset, int nob)
{
        struct kib_net *net = ni->ni_data;
        struct page *page;
        struct scatterlist *sg;
        unsigned long vaddr;
        int fragnob;
        int page_offset;

        LASSERT(nob > 0);
        LASSERT(niov > 0);
        LASSERT(net);

        while (offset >= iov->iov_len) {
                offset -= iov->iov_len;
                niov--;
                iov++;
                LASSERT(niov > 0);
        }

        sg = tx->tx_frags;
        do {
                LASSERT(niov > 0);

                vaddr = ((unsigned long)iov->iov_base) + offset;
                page_offset = vaddr & (PAGE_SIZE - 1);
                page = kiblnd_kvaddr_to_page(vaddr);
                if (!page) {
                        CERROR("Can't find page\n");
                        return -EFAULT;
                }

                fragnob = min((int)(iov->iov_len - offset), nob);
                fragnob = min(fragnob, (int)PAGE_SIZE - page_offset);

                sg_set_page(sg, page, fragnob, page_offset);
                sg = sg_next(sg);
                if (!sg) {
                        CERROR("lacking enough sg entries to map tx\n");
                        return -EFAULT;
                }

                if (offset + fragnob < iov->iov_len) {
                        offset += fragnob;
                } else {
                        offset = 0;
                        iov++;
                        niov--;
                }
                nob -= fragnob;
        } while (nob > 0);

        return kiblnd_map_tx(ni, tx, rd, sg - tx->tx_frags);
}

static int
kiblnd_setup_rd_kiov(lnet_ni_t *ni, struct kib_tx *tx, struct kib_rdma_desc *rd,
                     int nkiov, const lnet_kiov_t *kiov, int offset, int nob)
{
        struct kib_net *net = ni->ni_data;
        struct scatterlist *sg;
        int fragnob;

        CDEBUG(D_NET, "niov %d offset %d nob %d\n", nkiov, offset, nob);

        LASSERT(nob > 0);
        LASSERT(nkiov > 0);
        LASSERT(net);

        while (offset >= kiov->bv_len) {
                offset -= kiov->bv_len;
                nkiov--;
                kiov++;
                LASSERT(nkiov > 0);
        }

        sg = tx->tx_frags;
        do {
                LASSERT(nkiov > 0);

                fragnob = min((int)(kiov->bv_len - offset), nob);

                sg_set_page(sg, kiov->bv_page, fragnob,
                            kiov->bv_offset + offset);
                sg = sg_next(sg);
                if (!sg) {
                        CERROR("lacking enough sg entries to map tx\n");
                        return -EFAULT;
                }

                offset = 0;
                kiov++;
                nkiov--;
                nob -= fragnob;
        } while (nob > 0);

        return kiblnd_map_tx(ni, tx, rd, sg - tx->tx_frags);
}

static int
kiblnd_post_tx_locked(struct kib_conn *conn, struct kib_tx *tx, int credit)
        __must_hold(&conn->ibc_lock)
{
        struct kib_msg *msg = tx->tx_msg;
        struct kib_peer *peer = conn->ibc_peer;
        struct lnet_ni *ni = peer->ibp_ni;
        int ver = conn->ibc_version;
        int rc;
        int done;

        LASSERT(tx->tx_queued);
        /* We rely on this for QP sizing */
        LASSERT(tx->tx_nwrq > 0);

        LASSERT(!credit || credit == 1);
        LASSERT(conn->ibc_outstanding_credits >= 0);
        LASSERT(conn->ibc_outstanding_credits <= conn->ibc_queue_depth);
        LASSERT(conn->ibc_credits >= 0);
        LASSERT(conn->ibc_credits <= conn->ibc_queue_depth);

        if (conn->ibc_nsends_posted == kiblnd_concurrent_sends(ver, ni)) {
                /* tx completions outstanding... */
                CDEBUG(D_NET, "%s: posted enough\n",
                       libcfs_nid2str(peer->ibp_nid));
                return -EAGAIN;
        }

        if (credit && !conn->ibc_credits) {   /* no credits */
                CDEBUG(D_NET, "%s: no credits\n",
                       libcfs_nid2str(peer->ibp_nid));
                return -EAGAIN;
        }

        if (credit && !IBLND_OOB_CAPABLE(ver) &&
            conn->ibc_credits == 1 &&   /* last credit reserved */
            msg->ibm_type != IBLND_MSG_NOOP) {      /* for NOOP */
                CDEBUG(D_NET, "%s: not using last credit\n",
                       libcfs_nid2str(peer->ibp_nid));
                return -EAGAIN;
        }

        /* NB don't drop ibc_lock before bumping tx_sending */
        list_del(&tx->tx_list);
        tx->tx_queued = 0;

        if (msg->ibm_type == IBLND_MSG_NOOP &&
            (!kiblnd_need_noop(conn) ||     /* redundant NOOP */
             (IBLND_OOB_CAPABLE(ver) && /* posted enough NOOP */
              conn->ibc_noops_posted == IBLND_OOB_MSGS(ver)))) {
                /*
                 * OK to drop when posted enough NOOPs, since
                 * kiblnd_check_sends_locked will queue NOOP again when
                 * posted NOOPs complete
                 */
                spin_unlock(&conn->ibc_lock);
                kiblnd_tx_done(peer->ibp_ni, tx);
                spin_lock(&conn->ibc_lock);
                CDEBUG(D_NET, "%s(%d): redundant or enough NOOP\n",
                       libcfs_nid2str(peer->ibp_nid),
                       conn->ibc_noops_posted);
                return 0;
        }

        kiblnd_pack_msg(peer->ibp_ni, msg, ver, conn->ibc_outstanding_credits,
                        peer->ibp_nid, conn->ibc_incarnation);

        conn->ibc_credits -= credit;
        conn->ibc_outstanding_credits = 0;
        conn->ibc_nsends_posted++;
        if (msg->ibm_type == IBLND_MSG_NOOP)
                conn->ibc_noops_posted++;

        /*
         * CAVEAT EMPTOR!  This tx could be the PUT_DONE of an RDMA
         * PUT.  If so, it was first queued here as a PUT_REQ, sent and
         * stashed on ibc_active_txs, matched by an incoming PUT_ACK,
         * and then re-queued here.  It's (just) possible that
         * tx_sending is non-zero if we've not done the tx_complete()
         * from the first send; hence the ++ rather than = below.
         */
        tx->tx_sending++;
        list_add(&tx->tx_list, &conn->ibc_active_txs);

        /* I'm still holding ibc_lock! */
        if (conn->ibc_state != IBLND_CONN_ESTABLISHED) {
                rc = -ECONNABORTED;
        } else if (tx->tx_pool->tpo_pool.po_failed ||
                 conn->ibc_hdev != tx->tx_pool->tpo_hdev) {
                /* close_conn will launch failover */
                rc = -ENETDOWN;
        } else {
                struct kib_fast_reg_descriptor *frd = tx->fmr.fmr_frd;
                struct ib_send_wr *bad = &tx->tx_wrq[tx->tx_nwrq - 1].wr;
                struct ib_send_wr *wrq = &tx->tx_wrq[0].wr;

                if (frd) {
                        if (!frd->frd_valid) {
                                wrq = &frd->frd_inv_wr;
                                wrq->next = &frd->frd_fastreg_wr.wr;
                        } else {
                                wrq = &frd->frd_fastreg_wr.wr;
                        }
                        frd->frd_fastreg_wr.wr.next = &tx->tx_wrq[0].wr;
                }

                LASSERTF(bad->wr_id == kiblnd_ptr2wreqid(tx, IBLND_WID_TX),
                         "bad wr_id %llx, opc %d, flags %d, peer: %s\n",
                         bad->wr_id, bad->opcode, bad->send_flags,
                         libcfs_nid2str(conn->ibc_peer->ibp_nid));
                bad = NULL;
                rc = ib_post_send(conn->ibc_cmid->qp, wrq, &bad);
        }

        conn->ibc_last_send = jiffies;

        if (!rc)
                return 0;

        /*
         * NB credits are transferred in the actual
         * message, which can only be the last work item
         */
        conn->ibc_credits += credit;
        conn->ibc_outstanding_credits += msg->ibm_credits;
        conn->ibc_nsends_posted--;
        if (msg->ibm_type == IBLND_MSG_NOOP)
                conn->ibc_noops_posted--;

        tx->tx_status = rc;
        tx->tx_waiting = 0;
        tx->tx_sending--;

        done = !tx->tx_sending;
        if (done)
                list_del(&tx->tx_list);

        spin_unlock(&conn->ibc_lock);

        if (conn->ibc_state == IBLND_CONN_ESTABLISHED)
                CERROR("Error %d posting transmit to %s\n",
                       rc, libcfs_nid2str(peer->ibp_nid));
        else
                CDEBUG(D_NET, "Error %d posting transmit to %s\n",
                       rc, libcfs_nid2str(peer->ibp_nid));

        kiblnd_close_conn(conn, rc);

        if (done)
                kiblnd_tx_done(peer->ibp_ni, tx);

        spin_lock(&conn->ibc_lock);

        return -EIO;
}

static void
kiblnd_check_sends_locked(struct kib_conn *conn)
{
        int ver = conn->ibc_version;
        lnet_ni_t *ni = conn->ibc_peer->ibp_ni;
        struct kib_tx *tx;

        /* Don't send anything until after the connection is established */
        if (conn->ibc_state < IBLND_CONN_ESTABLISHED) {
                CDEBUG(D_NET, "%s too soon\n",
                       libcfs_nid2str(conn->ibc_peer->ibp_nid));
                return;
        }

        LASSERT(conn->ibc_nsends_posted <= kiblnd_concurrent_sends(ver, ni));
        LASSERT(!IBLND_OOB_CAPABLE(ver) ||
                conn->ibc_noops_posted <= IBLND_OOB_MSGS(ver));
        LASSERT(conn->ibc_reserved_credits >= 0);

        while (conn->ibc_reserved_credits > 0 &&
               !list_empty(&conn->ibc_tx_queue_rsrvd)) {
                tx = list_entry(conn->ibc_tx_queue_rsrvd.next,
                                struct kib_tx, tx_list);
                list_del(&tx->tx_list);
                list_add_tail(&tx->tx_list, &conn->ibc_tx_queue);
                conn->ibc_reserved_credits--;
        }

        if (kiblnd_need_noop(conn)) {
                spin_unlock(&conn->ibc_lock);

                tx = kiblnd_get_idle_tx(ni, conn->ibc_peer->ibp_nid);
                if (tx)
                        kiblnd_init_tx_msg(ni, tx, IBLND_MSG_NOOP, 0);

                spin_lock(&conn->ibc_lock);
                if (tx)
                        kiblnd_queue_tx_locked(tx, conn);
        }

        for (;;) {
                int credit;

                if (!list_empty(&conn->ibc_tx_queue_nocred)) {
                        credit = 0;
                        tx = list_entry(conn->ibc_tx_queue_nocred.next,
                                        struct kib_tx, tx_list);
                } else if (!list_empty(&conn->ibc_tx_noops)) {
                        LASSERT(!IBLND_OOB_CAPABLE(ver));
                        credit = 1;
                        tx = list_entry(conn->ibc_tx_noops.next,
                                        struct kib_tx, tx_list);
                } else if (!list_empty(&conn->ibc_tx_queue)) {
                        credit = 1;
                        tx = list_entry(conn->ibc_tx_queue.next,
                                        struct kib_tx, tx_list);
                } else {
                        break;
                }

                if (kiblnd_post_tx_locked(conn, tx, credit))
                        break;
        }
}

static void
kiblnd_tx_complete(struct kib_tx *tx, int status)
{
        int failed = (status != IB_WC_SUCCESS);
        struct kib_conn *conn = tx->tx_conn;
        int idle;

        LASSERT(tx->tx_sending > 0);

        if (failed) {
                if (conn->ibc_state == IBLND_CONN_ESTABLISHED)
                        CNETERR("Tx -> %s cookie %#llx sending %d waiting %d: failed %d\n",
                                libcfs_nid2str(conn->ibc_peer->ibp_nid),
                                tx->tx_cookie, tx->tx_sending, tx->tx_waiting,
                                status);

                kiblnd_close_conn(conn, -EIO);
        } else {
                kiblnd_peer_alive(conn->ibc_peer);
        }

        spin_lock(&conn->ibc_lock);

        /*
         * I could be racing with rdma completion.  Whoever makes 'tx' idle
         * gets to free it, which also drops its ref on 'conn'.
         */

        tx->tx_sending--;
        conn->ibc_nsends_posted--;
        if (tx->tx_msg->ibm_type == IBLND_MSG_NOOP)
                conn->ibc_noops_posted--;

        if (failed) {
                tx->tx_waiting = 0;          /* don't wait for peer */
                tx->tx_status = -EIO;
        }

        idle = !tx->tx_sending &&        /* This is the final callback */
               !tx->tx_waiting &&              /* Not waiting for peer */
               !tx->tx_queued;            /* Not re-queued (PUT_DONE) */
        if (idle)
                list_del(&tx->tx_list);

        kiblnd_check_sends_locked(conn);
        spin_unlock(&conn->ibc_lock);

        if (idle)
                kiblnd_tx_done(conn->ibc_peer->ibp_ni, tx);
}

static void
kiblnd_init_tx_msg(lnet_ni_t *ni, struct kib_tx *tx, int type, int body_nob)
{
        struct kib_hca_dev *hdev = tx->tx_pool->tpo_hdev;
        struct ib_sge *sge = &tx->tx_sge[tx->tx_nwrq];
        struct ib_rdma_wr *wrq = &tx->tx_wrq[tx->tx_nwrq];
        int nob = offsetof(struct kib_msg, ibm_u) + body_nob;
        struct ib_mr *mr = hdev->ibh_mrs;

        LASSERT(tx->tx_nwrq >= 0);
        LASSERT(tx->tx_nwrq < IBLND_MAX_RDMA_FRAGS + 1);
        LASSERT(nob <= IBLND_MSG_SIZE);
        LASSERT(mr);

        kiblnd_init_msg(tx->tx_msg, type, body_nob);

        sge->lkey   = mr->lkey;
        sge->addr   = tx->tx_msgaddr;
        sge->length = nob;

        memset(wrq, 0, sizeof(*wrq));

        wrq->wr.next       = NULL;
        wrq->wr.wr_id      = kiblnd_ptr2wreqid(tx, IBLND_WID_TX);
        wrq->wr.sg_list    = sge;
        wrq->wr.num_sge    = 1;
        wrq->wr.opcode     = IB_WR_SEND;
        wrq->wr.send_flags = IB_SEND_SIGNALED;

        tx->tx_nwrq++;
}

static int
kiblnd_init_rdma(struct kib_conn *conn, struct kib_tx *tx, int type,
                 int resid, struct kib_rdma_desc *dstrd, __u64 dstcookie)
{
        struct kib_msg *ibmsg = tx->tx_msg;
        struct kib_rdma_desc *srcrd = tx->tx_rd;
        struct ib_sge *sge = &tx->tx_sge[0];
        struct ib_rdma_wr *wrq, *next;
        int rc  = resid;
        int srcidx = 0;
        int dstidx = 0;
        int wrknob;

        LASSERT(!in_interrupt());
        LASSERT(!tx->tx_nwrq);
        LASSERT(type == IBLND_MSG_GET_DONE ||
                type == IBLND_MSG_PUT_DONE);

        if (kiblnd_rd_size(srcrd) > conn->ibc_max_frags << PAGE_SHIFT) {
                CERROR("RDMA is too large for peer %s (%d), src size: %d dst size: %d\n",
                       libcfs_nid2str(conn->ibc_peer->ibp_nid),
                       conn->ibc_max_frags << PAGE_SHIFT,
                       kiblnd_rd_size(srcrd), kiblnd_rd_size(dstrd));
                rc = -EMSGSIZE;
                goto too_big;
        }

        while (resid > 0) {
                if (srcidx >= srcrd->rd_nfrags) {
                        CERROR("Src buffer exhausted: %d frags\n", srcidx);
                        rc = -EPROTO;
                        break;
                }

                if (dstidx == dstrd->rd_nfrags) {
                        CERROR("Dst buffer exhausted: %d frags\n", dstidx);
                        rc = -EPROTO;
                        break;
                }

                if (tx->tx_nwrq >= IBLND_MAX_RDMA_FRAGS) {
                        CERROR("RDMA has too many fragments for peer %s (%d), src idx/frags: %d/%d dst idx/frags: %d/%d\n",
                               libcfs_nid2str(conn->ibc_peer->ibp_nid),
                               IBLND_MAX_RDMA_FRAGS,
                               srcidx, srcrd->rd_nfrags,
                               dstidx, dstrd->rd_nfrags);
                        rc = -EMSGSIZE;
                        break;
                }

                wrknob = min(min(kiblnd_rd_frag_size(srcrd, srcidx),
                                 kiblnd_rd_frag_size(dstrd, dstidx)),
                             (__u32)resid);

                sge = &tx->tx_sge[tx->tx_nwrq];
                sge->addr   = kiblnd_rd_frag_addr(srcrd, srcidx);
                sge->lkey   = kiblnd_rd_frag_key(srcrd, srcidx);
                sge->length = wrknob;

                wrq = &tx->tx_wrq[tx->tx_nwrq];
                next = wrq + 1;

                wrq->wr.next       = &next->wr;
                wrq->wr.wr_id      = kiblnd_ptr2wreqid(tx, IBLND_WID_RDMA);
                wrq->wr.sg_list    = sge;
                wrq->wr.num_sge    = 1;
                wrq->wr.opcode     = IB_WR_RDMA_WRITE;
                wrq->wr.send_flags = 0;

                wrq->remote_addr = kiblnd_rd_frag_addr(dstrd, dstidx);
                wrq->rkey        = kiblnd_rd_frag_key(dstrd, dstidx);

                srcidx = kiblnd_rd_consume_frag(srcrd, srcidx, wrknob);
                dstidx = kiblnd_rd_consume_frag(dstrd, dstidx, wrknob);

                resid -= wrknob;

                tx->tx_nwrq++;
                wrq++;
                sge++;
        }
too_big:
        if (rc < 0)                          /* no RDMA if completing with failure */
                tx->tx_nwrq = 0;

        ibmsg->ibm_u.completion.ibcm_status = rc;
        ibmsg->ibm_u.completion.ibcm_cookie = dstcookie;
        kiblnd_init_tx_msg(conn->ibc_peer->ibp_ni, tx,
                           type, sizeof(struct kib_completion_msg));

        return rc;
}

static void
kiblnd_queue_tx_locked(struct kib_tx *tx, struct kib_conn *conn)
{
        struct list_head *q;

        LASSERT(tx->tx_nwrq > 0);             /* work items set up */
        LASSERT(!tx->tx_queued);               /* not queued for sending already */
        LASSERT(conn->ibc_state >= IBLND_CONN_ESTABLISHED);

        tx->tx_queued = 1;
        tx->tx_deadline = jiffies +
                          msecs_to_jiffies(*kiblnd_tunables.kib_timeout *
                                           MSEC_PER_SEC);

        if (!tx->tx_conn) {
                kiblnd_conn_addref(conn);
                tx->tx_conn = conn;
                LASSERT(tx->tx_msg->ibm_type != IBLND_MSG_PUT_DONE);
        } else {
                /* PUT_DONE first attached to conn as a PUT_REQ */
                LASSERT(tx->tx_conn == conn);
                LASSERT(tx->tx_msg->ibm_type == IBLND_MSG_PUT_DONE);
        }

        switch (tx->tx_msg->ibm_type) {
        default:
                LBUG();

        case IBLND_MSG_PUT_REQ:
        case IBLND_MSG_GET_REQ:
                q = &conn->ibc_tx_queue_rsrvd;
                break;

        case IBLND_MSG_PUT_NAK:
        case IBLND_MSG_PUT_ACK:
        case IBLND_MSG_PUT_DONE:
        case IBLND_MSG_GET_DONE:
                q = &conn->ibc_tx_queue_nocred;
                break;

        case IBLND_MSG_NOOP:
                if (IBLND_OOB_CAPABLE(conn->ibc_version))
                        q = &conn->ibc_tx_queue_nocred;
                else
                        q = &conn->ibc_tx_noops;
                break;

        case IBLND_MSG_IMMEDIATE:
                q = &conn->ibc_tx_queue;
                break;
        }

        list_add_tail(&tx->tx_list, q);
}

static void
kiblnd_queue_tx(struct kib_tx *tx, struct kib_conn *conn)
{
        spin_lock(&conn->ibc_lock);
        kiblnd_queue_tx_locked(tx, conn);
        kiblnd_check_sends_locked(conn);
        spin_unlock(&conn->ibc_lock);
}

static int kiblnd_resolve_addr(struct rdma_cm_id *cmid,
                               struct sockaddr_in *srcaddr,
                               struct sockaddr_in *dstaddr,
                               int timeout_ms)
{
        unsigned short port;
        int rc;

        /* allow the port to be reused */
        rc = rdma_set_reuseaddr(cmid, 1);
        if (rc) {
                CERROR("Unable to set reuse on cmid: %d\n", rc);
                return rc;
        }

        /* look for a free privileged port */
        for (port = PROT_SOCK - 1; port > 0; port--) {
                srcaddr->sin_port = htons(port);
                rc = rdma_resolve_addr(cmid,
                                       (struct sockaddr *)srcaddr,
                                       (struct sockaddr *)dstaddr,
                                       timeout_ms);
                if (!rc) {
                        CDEBUG(D_NET, "bound to port %hu\n", port);
                        return 0;
                } else if (rc == -EADDRINUSE || rc == -EADDRNOTAVAIL) {
                        CDEBUG(D_NET, "bind to port %hu failed: %d\n",
                               port, rc);
                } else {
                        return rc;
                }
        }

        CERROR("Failed to bind to a free privileged port\n");
        return rc;
}

static void
kiblnd_connect_peer(struct kib_peer *peer)
{
        struct rdma_cm_id *cmid;
        struct kib_dev *dev;
        struct kib_net *net = peer->ibp_ni->ni_data;
        struct sockaddr_in srcaddr;
        struct sockaddr_in dstaddr;
        int rc;

        LASSERT(net);
        LASSERT(peer->ibp_connecting > 0);
        LASSERT(!peer->ibp_reconnecting);

        cmid = kiblnd_rdma_create_id(kiblnd_cm_callback, peer, RDMA_PS_TCP,
                                     IB_QPT_RC);

        if (IS_ERR(cmid)) {
                CERROR("Can't create CMID for %s: %ld\n",
                       libcfs_nid2str(peer->ibp_nid), PTR_ERR(cmid));
                rc = PTR_ERR(cmid);
                goto failed;
        }

        dev = net->ibn_dev;
        memset(&srcaddr, 0, sizeof(srcaddr));
        srcaddr.sin_family = AF_INET;
        srcaddr.sin_addr.s_addr = htonl(dev->ibd_ifip);

        memset(&dstaddr, 0, sizeof(dstaddr));
        dstaddr.sin_family = AF_INET;
        dstaddr.sin_port = htons(*kiblnd_tunables.kib_service);
        dstaddr.sin_addr.s_addr = htonl(LNET_NIDADDR(peer->ibp_nid));

        kiblnd_peer_addref(peer);              /* cmid's ref */

        if (*kiblnd_tunables.kib_use_priv_port) {
                rc = kiblnd_resolve_addr(cmid, &srcaddr, &dstaddr,
                                         *kiblnd_tunables.kib_timeout * 1000);
        } else {
                rc = rdma_resolve_addr(cmid,
                                       (struct sockaddr *)&srcaddr,
                                       (struct sockaddr *)&dstaddr,
                                       *kiblnd_tunables.kib_timeout * 1000);
        }
        if (rc) {
                /* Can't initiate address resolution:  */
                CERROR("Can't resolve addr for %s: %d\n",
                       libcfs_nid2str(peer->ibp_nid), rc);
                goto failed2;
        }

        LASSERT(cmid->device);
        CDEBUG(D_NET, "%s: connection bound to %s:%pI4h:%s\n",
               libcfs_nid2str(peer->ibp_nid), dev->ibd_ifname,
               &dev->ibd_ifip, cmid->device->name);

        return;

 failed2:
        kiblnd_peer_connect_failed(peer, 1, rc);
        kiblnd_peer_decref(peer);              /* cmid's ref */
        rdma_destroy_id(cmid);
        return;
 failed:
        kiblnd_peer_connect_failed(peer, 1, rc);
}

bool
kiblnd_reconnect_peer(struct kib_peer *peer)
{
        rwlock_t *glock = &kiblnd_data.kib_global_lock;
        char *reason = NULL;
        struct list_head txs;
        unsigned long flags;

        INIT_LIST_HEAD(&txs);

        write_lock_irqsave(glock, flags);
        if (!peer->ibp_reconnecting) {
                if (peer->ibp_accepting)
                        reason = "accepting";
                else if (peer->ibp_connecting)
                        reason = "connecting";
                else if (!list_empty(&peer->ibp_conns))
                        reason = "connected";
                else /* connected then closed */
                        reason = "closed";

                goto no_reconnect;
        }

        LASSERT(!peer->ibp_accepting && !peer->ibp_connecting &&
                list_empty(&peer->ibp_conns));
        peer->ibp_reconnecting = 0;

        if (!kiblnd_peer_active(peer)) {
                list_splice_init(&peer->ibp_tx_queue, &txs);
                reason = "unlinked";
                goto no_reconnect;
        }

        peer->ibp_connecting++;
        peer->ibp_reconnected++;
        write_unlock_irqrestore(glock, flags);

        kiblnd_connect_peer(peer);
        return true;

no_reconnect:
        write_unlock_irqrestore(glock, flags);

        CWARN("Abort reconnection of %s: %s\n",
              libcfs_nid2str(peer->ibp_nid), reason);
        kiblnd_txlist_done(peer->ibp_ni, &txs, -ECONNABORTED);
        return false;
}

void
kiblnd_launch_tx(lnet_ni_t *ni, struct kib_tx *tx, lnet_nid_t nid)
{
        struct kib_peer *peer;
        struct kib_peer *peer2;
        struct kib_conn *conn;
        rwlock_t *g_lock = &kiblnd_data.kib_global_lock;
        unsigned long flags;
        int rc;

        /*
         * If I get here, I've committed to send, so I complete the tx with
         * failure on any problems
         */
        LASSERT(!tx || !tx->tx_conn); /* only set when assigned a conn */
        LASSERT(!tx || tx->tx_nwrq > 0);     /* work items have been set up */

        /*
         * First time, just use a read lock since I expect to find my peer
         * connected
         */
        read_lock_irqsave(g_lock, flags);

        peer = kiblnd_find_peer_locked(nid);
        if (peer && !list_empty(&peer->ibp_conns)) {
                /* Found a peer with an established connection */
                conn = kiblnd_get_conn_locked(peer);
                kiblnd_conn_addref(conn); /* 1 ref for me... */

                read_unlock_irqrestore(g_lock, flags);

                if (tx)
                        kiblnd_queue_tx(tx, conn);
                kiblnd_conn_decref(conn); /* ...to here */
                return;
        }

        read_unlock(g_lock);
        /* Re-try with a write lock */
        write_lock(g_lock);

        peer = kiblnd_find_peer_locked(nid);
        if (peer) {
                if (list_empty(&peer->ibp_conns)) {
                        /* found a peer, but it's still connecting... */
                        LASSERT(kiblnd_peer_connecting(peer));
                        if (tx)
                                list_add_tail(&tx->tx_list,
                                              &peer->ibp_tx_queue);
                        write_unlock_irqrestore(g_lock, flags);
                } else {
                        conn = kiblnd_get_conn_locked(peer);
                        kiblnd_conn_addref(conn); /* 1 ref for me... */

                        write_unlock_irqrestore(g_lock, flags);

                        if (tx)
                                kiblnd_queue_tx(tx, conn);
                        kiblnd_conn_decref(conn); /* ...to here */
                }
                return;
        }

        write_unlock_irqrestore(g_lock, flags);

        /* Allocate a peer ready to add to the peer table and retry */
        rc = kiblnd_create_peer(ni, &peer, nid);
        if (rc) {
                CERROR("Can't create peer %s\n", libcfs_nid2str(nid));
                if (tx) {
                        tx->tx_status = -EHOSTUNREACH;
                        tx->tx_waiting = 0;
                        kiblnd_tx_done(ni, tx);
                }
                return;
        }

        write_lock_irqsave(g_lock, flags);

        peer2 = kiblnd_find_peer_locked(nid);
        if (peer2) {
                if (list_empty(&peer2->ibp_conns)) {
                        /* found a peer, but it's still connecting... */
                        LASSERT(kiblnd_peer_connecting(peer2));
                        if (tx)
                                list_add_tail(&tx->tx_list,
                                              &peer2->ibp_tx_queue);
                        write_unlock_irqrestore(g_lock, flags);
                } else {
                        conn = kiblnd_get_conn_locked(peer2);
                        kiblnd_conn_addref(conn); /* 1 ref for me... */

                        write_unlock_irqrestore(g_lock, flags);

                        if (tx)
                                kiblnd_queue_tx(tx, conn);
                        kiblnd_conn_decref(conn); /* ...to here */
                }

                kiblnd_peer_decref(peer);
                return;
        }

        /* Brand new peer */
        LASSERT(!peer->ibp_connecting);
        peer->ibp_connecting = 1;

        /* always called with a ref on ni, which prevents ni being shutdown */
        LASSERT(!((struct kib_net *)ni->ni_data)->ibn_shutdown);

        if (tx)
                list_add_tail(&tx->tx_list, &peer->ibp_tx_queue);

        kiblnd_peer_addref(peer);
        list_add_tail(&peer->ibp_list, kiblnd_nid2peerlist(nid));

        write_unlock_irqrestore(g_lock, flags);

        kiblnd_connect_peer(peer);
        kiblnd_peer_decref(peer);
}

int
kiblnd_send(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg)
{
        lnet_hdr_t *hdr = &lntmsg->msg_hdr;
        int type = lntmsg->msg_type;
        lnet_process_id_t target = lntmsg->msg_target;
        int target_is_router = lntmsg->msg_target_is_router;
        int routing = lntmsg->msg_routing;
        unsigned int payload_niov = lntmsg->msg_niov;
        struct kvec *payload_iov = lntmsg->msg_iov;
        lnet_kiov_t *payload_kiov = lntmsg->msg_kiov;
        unsigned int payload_offset = lntmsg->msg_offset;
        unsigned int payload_nob = lntmsg->msg_len;
        struct iov_iter from;
        struct kib_msg *ibmsg;
        struct kib_rdma_desc  *rd;
        struct kib_tx *tx;
        int nob;
        int rc;

        /* NB 'private' is different depending on what we're sending.... */

        CDEBUG(D_NET, "sending %d bytes in %d frags to %s\n",
               payload_nob, payload_niov, libcfs_id2str(target));

        LASSERT(!payload_nob || payload_niov > 0);
        LASSERT(payload_niov <= LNET_MAX_IOV);

        /* Thread context */
        LASSERT(!in_interrupt());
        /* payload is either all vaddrs or all pages */
        LASSERT(!(payload_kiov && payload_iov));

        if (payload_kiov)
                iov_iter_bvec(&from, ITER_BVEC | WRITE,
                              payload_kiov, payload_niov,
                              payload_nob + payload_offset);
        else
                iov_iter_kvec(&from, ITER_KVEC | WRITE,
                              payload_iov, payload_niov,
                              payload_nob + payload_offset);

        iov_iter_advance(&from, payload_offset);

        switch (type) {
        default:
                LBUG();
                return -EIO;

        case LNET_MSG_ACK:
                LASSERT(!payload_nob);
                break;

        case LNET_MSG_GET:
                if (routing || target_is_router)
                        break;            /* send IMMEDIATE */

                /* is the REPLY message too small for RDMA? */
                nob = offsetof(struct kib_msg, ibm_u.immediate.ibim_payload[lntmsg->msg_md->md_length]);
                if (nob <= IBLND_MSG_SIZE)
                        break;            /* send IMMEDIATE */

                tx = kiblnd_get_idle_tx(ni, target.nid);
                if (!tx) {
                        CERROR("Can't allocate txd for GET to %s\n",
                               libcfs_nid2str(target.nid));
                        return -ENOMEM;
                }

                ibmsg = tx->tx_msg;
                rd = &ibmsg->ibm_u.get.ibgm_rd;
                if (!(lntmsg->msg_md->md_options & LNET_MD_KIOV))
                        rc = kiblnd_setup_rd_iov(ni, tx, rd,
                                                 lntmsg->msg_md->md_niov,
                                                 lntmsg->msg_md->md_iov.iov,
                                                 0, lntmsg->msg_md->md_length);
                else
                        rc = kiblnd_setup_rd_kiov(ni, tx, rd,
                                                  lntmsg->msg_md->md_niov,
                                                  lntmsg->msg_md->md_iov.kiov,
                                                  0, lntmsg->msg_md->md_length);
                if (rc) {
                        CERROR("Can't setup GET sink for %s: %d\n",
                               libcfs_nid2str(target.nid), rc);
                        kiblnd_tx_done(ni, tx);
                        return -EIO;
                }

                nob = offsetof(struct kib_get_msg, ibgm_rd.rd_frags[rd->rd_nfrags]);
                ibmsg->ibm_u.get.ibgm_cookie = tx->tx_cookie;
                ibmsg->ibm_u.get.ibgm_hdr = *hdr;

                kiblnd_init_tx_msg(ni, tx, IBLND_MSG_GET_REQ, nob);

                tx->tx_lntmsg[1] = lnet_create_reply_msg(ni, lntmsg);
                if (!tx->tx_lntmsg[1]) {
                        CERROR("Can't create reply for GET -> %s\n",
                               libcfs_nid2str(target.nid));
                        kiblnd_tx_done(ni, tx);
                        return -EIO;
                }

                tx->tx_lntmsg[0] = lntmsg;      /* finalise lntmsg[0,1] on completion */
                tx->tx_waiting = 1;          /* waiting for GET_DONE */
                kiblnd_launch_tx(ni, tx, target.nid);
                return 0;

        case LNET_MSG_REPLY:
        case LNET_MSG_PUT:
                /* Is the payload small enough not to need RDMA? */
                nob = offsetof(struct kib_msg, ibm_u.immediate.ibim_payload[payload_nob]);
                if (nob <= IBLND_MSG_SIZE)
                        break;            /* send IMMEDIATE */

                tx = kiblnd_get_idle_tx(ni, target.nid);
                if (!tx) {
                        CERROR("Can't allocate %s txd for %s\n",
                               type == LNET_MSG_PUT ? "PUT" : "REPLY",
                               libcfs_nid2str(target.nid));
                        return -ENOMEM;
                }

                if (!payload_kiov)
                        rc = kiblnd_setup_rd_iov(ni, tx, tx->tx_rd,
                                                 payload_niov, payload_iov,
                                                 payload_offset, payload_nob);
                else
                        rc = kiblnd_setup_rd_kiov(ni, tx, tx->tx_rd,
                                                  payload_niov, payload_kiov,
                                                  payload_offset, payload_nob);
                if (rc) {
                        CERROR("Can't setup PUT src for %s: %d\n",
                               libcfs_nid2str(target.nid), rc);
                        kiblnd_tx_done(ni, tx);
                        return -EIO;
                }

                ibmsg = tx->tx_msg;
                ibmsg->ibm_u.putreq.ibprm_hdr = *hdr;
                ibmsg->ibm_u.putreq.ibprm_cookie = tx->tx_cookie;
                kiblnd_init_tx_msg(ni, tx, IBLND_MSG_PUT_REQ, sizeof(struct kib_putreq_msg));

                tx->tx_lntmsg[0] = lntmsg;      /* finalise lntmsg on completion */
                tx->tx_waiting = 1;          /* waiting for PUT_{ACK,NAK} */
                kiblnd_launch_tx(ni, tx, target.nid);
                return 0;
        }

        /* send IMMEDIATE */

        LASSERT(offsetof(struct kib_msg, ibm_u.immediate.ibim_payload[payload_nob])
                 <= IBLND_MSG_SIZE);

        tx = kiblnd_get_idle_tx(ni, target.nid);
        if (!tx) {
                CERROR("Can't send %d to %s: tx descs exhausted\n",
                       type, libcfs_nid2str(target.nid));
                return -ENOMEM;
        }

        ibmsg = tx->tx_msg;
        ibmsg->ibm_u.immediate.ibim_hdr = *hdr;

        copy_from_iter(&ibmsg->ibm_u.immediate.ibim_payload, IBLND_MSG_SIZE,
                       &from);
        nob = offsetof(struct kib_immediate_msg, ibim_payload[payload_nob]);
        kiblnd_init_tx_msg(ni, tx, IBLND_MSG_IMMEDIATE, nob);

        tx->tx_lntmsg[0] = lntmsg;            /* finalise lntmsg on completion */
        kiblnd_launch_tx(ni, tx, target.nid);
        return 0;
}

static void
kiblnd_reply(lnet_ni_t *ni, struct kib_rx *rx, lnet_msg_t *lntmsg)
{
        lnet_process_id_t target = lntmsg->msg_target;
        unsigned int niov = lntmsg->msg_niov;
        struct kvec *iov = lntmsg->msg_iov;
        lnet_kiov_t *kiov = lntmsg->msg_kiov;
        unsigned int offset = lntmsg->msg_offset;
        unsigned int nob = lntmsg->msg_len;
        struct kib_tx *tx;
        int rc;

        tx = kiblnd_get_idle_tx(ni, rx->rx_conn->ibc_peer->ibp_nid);
        if (!tx) {
                CERROR("Can't get tx for REPLY to %s\n",
                       libcfs_nid2str(target.nid));
                goto failed_0;
        }

        if (!nob)
                rc = 0;
        else if (!kiov)
                rc = kiblnd_setup_rd_iov(ni, tx, tx->tx_rd,
                                         niov, iov, offset, nob);
        else
                rc = kiblnd_setup_rd_kiov(ni, tx, tx->tx_rd,
                                          niov, kiov, offset, nob);

        if (rc) {
                CERROR("Can't setup GET src for %s: %d\n",
                       libcfs_nid2str(target.nid), rc);
                goto failed_1;
        }

        rc = kiblnd_init_rdma(rx->rx_conn, tx,
                              IBLND_MSG_GET_DONE, nob,
                              &rx->rx_msg->ibm_u.get.ibgm_rd,
                              rx->rx_msg->ibm_u.get.ibgm_cookie);
        if (rc < 0) {
                CERROR("Can't setup rdma for GET from %s: %d\n",
                       libcfs_nid2str(target.nid), rc);
                goto failed_1;
        }

        if (!nob) {
                /* No RDMA: local completion may happen now! */
                lnet_finalize(ni, lntmsg, 0);
        } else {
                /* RDMA: lnet_finalize(lntmsg) when it completes */
                tx->tx_lntmsg[0] = lntmsg;
        }

        kiblnd_queue_tx(tx, rx->rx_conn);
        return;

 failed_1:
        kiblnd_tx_done(ni, tx);
 failed_0:
        lnet_finalize(ni, lntmsg, -EIO);
}

int
kiblnd_recv(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
            struct iov_iter *to, unsigned int rlen)
{
        struct kib_rx *rx = private;
        struct kib_msg *rxmsg = rx->rx_msg;
        struct kib_conn *conn = rx->rx_conn;
        struct kib_tx *tx;
        int nob;
        int post_credit = IBLND_POSTRX_PEER_CREDIT;
        int rc = 0;

        LASSERT(iov_iter_count(to) <= rlen);
        LASSERT(!in_interrupt());
        /* Either all pages or all vaddrs */

        switch (rxmsg->ibm_type) {
        default:
                LBUG();

        case IBLND_MSG_IMMEDIATE:
                nob = offsetof(struct kib_msg, ibm_u.immediate.ibim_payload[rlen]);
                if (nob > rx->rx_nob) {
                        CERROR("Immediate message from %s too big: %d(%d)\n",
                               libcfs_nid2str(rxmsg->ibm_u.immediate.ibim_hdr.src_nid),
                               nob, rx->rx_nob);
                        rc = -EPROTO;
                        break;
                }

                copy_to_iter(&rxmsg->ibm_u.immediate.ibim_payload,
                             IBLND_MSG_SIZE, to);
                lnet_finalize(ni, lntmsg, 0);
                break;

        case IBLND_MSG_PUT_REQ: {
                struct kib_msg  *txmsg;
                struct kib_rdma_desc *rd;

                if (!iov_iter_count(to)) {
                        lnet_finalize(ni, lntmsg, 0);
                        kiblnd_send_completion(rx->rx_conn, IBLND_MSG_PUT_NAK, 0,
                                               rxmsg->ibm_u.putreq.ibprm_cookie);
                        break;
                }

                tx = kiblnd_get_idle_tx(ni, conn->ibc_peer->ibp_nid);
                if (!tx) {
                        CERROR("Can't allocate tx for %s\n",
                               libcfs_nid2str(conn->ibc_peer->ibp_nid));
                        /* Not replying will break the connection */
                        rc = -ENOMEM;
                        break;
                }

                txmsg = tx->tx_msg;
                rd = &txmsg->ibm_u.putack.ibpam_rd;
                if (!(to->type & ITER_BVEC))
                        rc = kiblnd_setup_rd_iov(ni, tx, rd,
                                                 to->nr_segs, to->kvec,
                                                 to->iov_offset,
                                                 iov_iter_count(to));
                else
                        rc = kiblnd_setup_rd_kiov(ni, tx, rd,
                                                  to->nr_segs, to->bvec,
                                                  to->iov_offset,
                                                  iov_iter_count(to));
                if (rc) {
                        CERROR("Can't setup PUT sink for %s: %d\n",
                               libcfs_nid2str(conn->ibc_peer->ibp_nid), rc);
                        kiblnd_tx_done(ni, tx);
                        /* tell peer it's over */
                        kiblnd_send_completion(rx->rx_conn, IBLND_MSG_PUT_NAK, rc,
                                               rxmsg->ibm_u.putreq.ibprm_cookie);
                        break;
                }

                nob = offsetof(struct kib_putack_msg, ibpam_rd.rd_frags[rd->rd_nfrags]);
                txmsg->ibm_u.putack.ibpam_src_cookie = rxmsg->ibm_u.putreq.ibprm_cookie;
                txmsg->ibm_u.putack.ibpam_dst_cookie = tx->tx_cookie;

                kiblnd_init_tx_msg(ni, tx, IBLND_MSG_PUT_ACK, nob);

                tx->tx_lntmsg[0] = lntmsg;      /* finalise lntmsg on completion */
                tx->tx_waiting = 1;          /* waiting for PUT_DONE */
                kiblnd_queue_tx(tx, conn);

                /* reposted buffer reserved for PUT_DONE */
                post_credit = IBLND_POSTRX_NO_CREDIT;
                break;
                }

        case IBLND_MSG_GET_REQ:
                if (lntmsg) {
                        /* Optimized GET; RDMA lntmsg's payload */
                        kiblnd_reply(ni, rx, lntmsg);
                } else {
                        /* GET didn't match anything */
                        kiblnd_send_completion(rx->rx_conn, IBLND_MSG_GET_DONE,
                                               -ENODATA,
                                               rxmsg->ibm_u.get.ibgm_cookie);
                }
                break;
        }

        kiblnd_post_rx(rx, post_credit);
        return rc;
}

int
kiblnd_thread_start(int (*fn)(void *arg), void *arg, char *name)
{
        struct task_struct *task = kthread_run(fn, arg, "%s", name);

        if (IS_ERR(task))
                return PTR_ERR(task);

        atomic_inc(&kiblnd_data.kib_nthreads);
        return 0;
}

static void
kiblnd_thread_fini(void)
{
        atomic_dec(&kiblnd_data.kib_nthreads);
}

static void
kiblnd_peer_alive(struct kib_peer *peer)
{
        /* This is racy, but everyone's only writing cfs_time_current() */
        peer->ibp_last_alive = cfs_time_current();
        mb();
}

static void
kiblnd_peer_notify(struct kib_peer *peer)
{
        int error = 0;
        unsigned long last_alive = 0;
        unsigned long flags;

        read_lock_irqsave(&kiblnd_data.kib_global_lock, flags);

        if (kiblnd_peer_idle(peer) && peer->ibp_error) {
                error = peer->ibp_error;
                peer->ibp_error = 0;

                last_alive = peer->ibp_last_alive;
        }

        read_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

        if (error)
                lnet_notify(peer->ibp_ni,
                            peer->ibp_nid, 0, last_alive);
}

void
kiblnd_close_conn_locked(struct kib_conn *conn, int error)
{
        /*
         * This just does the immediate housekeeping. 'error' is zero for a
         * normal shutdown which can happen only after the connection has been
         * established.  If the connection is established, schedule the
         * connection to be finished off by the connd. Otherwise the connd is
         * already dealing with it (either to set it up or tear it down).
         * Caller holds kib_global_lock exclusively in irq context
         */
        struct kib_peer *peer = conn->ibc_peer;
        struct kib_dev *dev;
        unsigned long flags;

        LASSERT(error || conn->ibc_state >= IBLND_CONN_ESTABLISHED);

        if (error && !conn->ibc_comms_error)
                conn->ibc_comms_error = error;

        if (conn->ibc_state != IBLND_CONN_ESTABLISHED)
                return; /* already being handled  */

        if (!error &&
            list_empty(&conn->ibc_tx_noops) &&
            list_empty(&conn->ibc_tx_queue) &&
            list_empty(&conn->ibc_tx_queue_rsrvd) &&
            list_empty(&conn->ibc_tx_queue_nocred) &&
            list_empty(&conn->ibc_active_txs)) {
                CDEBUG(D_NET, "closing conn to %s\n",
                       libcfs_nid2str(peer->ibp_nid));
        } else {
                CNETERR("Closing conn to %s: error %d%s%s%s%s%s\n",
                        libcfs_nid2str(peer->ibp_nid), error,
                        list_empty(&conn->ibc_tx_queue) ? "" : "(sending)",
                        list_empty(&conn->ibc_tx_noops) ? "" : "(sending_noops)",
                        list_empty(&conn->ibc_tx_queue_rsrvd) ? "" : "(sending_rsrvd)",
                        list_empty(&conn->ibc_tx_queue_nocred) ? "" : "(sending_nocred)",
                        list_empty(&conn->ibc_active_txs) ? "" : "(waiting)");
        }

        dev = ((struct kib_net *)peer->ibp_ni->ni_data)->ibn_dev;
        list_del(&conn->ibc_list);
        /* connd (see below) takes over ibc_list's ref */

        if (list_empty(&peer->ibp_conns) &&    /* no more conns */
            kiblnd_peer_active(peer)) {  /* still in peer table */
                kiblnd_unlink_peer_locked(peer);

                /* set/clear error on last conn */
                peer->ibp_error = conn->ibc_comms_error;
        }

        kiblnd_set_conn_state(conn, IBLND_CONN_CLOSING);

        if (error &&
            kiblnd_dev_can_failover(dev)) {
                list_add_tail(&dev->ibd_fail_list,
                              &kiblnd_data.kib_failed_devs);
                wake_up(&kiblnd_data.kib_failover_waitq);
        }

        spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);

        list_add_tail(&conn->ibc_list, &kiblnd_data.kib_connd_conns);
        wake_up(&kiblnd_data.kib_connd_waitq);

        spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);
}

void
kiblnd_close_conn(struct kib_conn *conn, int error)
{
        unsigned long flags;

        write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);

        kiblnd_close_conn_locked(conn, error);

        write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
}

static void
kiblnd_handle_early_rxs(struct kib_conn *conn)
{
        unsigned long flags;
        struct kib_rx *rx;
        struct kib_rx *tmp;

        LASSERT(!in_interrupt());
        LASSERT(conn->ibc_state >= IBLND_CONN_ESTABLISHED);

        write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
        list_for_each_entry_safe(rx, tmp, &conn->ibc_early_rxs, rx_list) {
                list_del(&rx->rx_list);
                write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

                kiblnd_handle_rx(rx);

                write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
        }
        write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
}

static void
kiblnd_abort_txs(struct kib_conn *conn, struct list_head *txs)
{
        LIST_HEAD(zombies);
        struct list_head *tmp;
        struct list_head *nxt;
        struct kib_tx *tx;

        spin_lock(&conn->ibc_lock);

        list_for_each_safe(tmp, nxt, txs) {
                tx = list_entry(tmp, struct kib_tx, tx_list);

                if (txs == &conn->ibc_active_txs) {
                        LASSERT(!tx->tx_queued);

                        LASSERT(tx->tx_waiting || tx->tx_sending);
                } else {
                        LASSERT(tx->tx_queued);
                }

                tx->tx_status = -ECONNABORTED;
                tx->tx_waiting = 0;

                if (!tx->tx_sending) {
                        tx->tx_queued = 0;
                        list_del(&tx->tx_list);
                        list_add(&tx->tx_list, &zombies);
                }
        }

        spin_unlock(&conn->ibc_lock);

        kiblnd_txlist_done(conn->ibc_peer->ibp_ni, &zombies, -ECONNABORTED);
}

static void
kiblnd_finalise_conn(struct kib_conn *conn)
{
        LASSERT(!in_interrupt());
        LASSERT(conn->ibc_state > IBLND_CONN_INIT);

        kiblnd_set_conn_state(conn, IBLND_CONN_DISCONNECTED);

        /*
         * abort_receives moves QP state to IB_QPS_ERR.  This is only required
         * for connections that didn't get as far as being connected, because
         * rdma_disconnect() does this for free.
         */
        kiblnd_abort_receives(conn);

        /*
         * Complete all tx descs not waiting for sends to complete.
         * NB we should be safe from RDMA now that the QP has changed state
         */
        kiblnd_abort_txs(conn, &conn->ibc_tx_noops);
        kiblnd_abort_txs(conn, &conn->ibc_tx_queue);
        kiblnd_abort_txs(conn, &conn->ibc_tx_queue_rsrvd);
        kiblnd_abort_txs(conn, &conn->ibc_tx_queue_nocred);
        kiblnd_abort_txs(conn, &conn->ibc_active_txs);

        kiblnd_handle_early_rxs(conn);
}

static void
kiblnd_peer_connect_failed(struct kib_peer *peer, int active, int error)
{
        LIST_HEAD(zombies);
        unsigned long flags;

        LASSERT(error);
        LASSERT(!in_interrupt());

        write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);

        if (active) {
                LASSERT(peer->ibp_connecting > 0);
                peer->ibp_connecting--;
        } else {
                LASSERT(peer->ibp_accepting > 0);
                peer->ibp_accepting--;
        }

        if (kiblnd_peer_connecting(peer)) {
                /* another connection attempt under way... */
                write_unlock_irqrestore(&kiblnd_data.kib_global_lock,
                                        flags);
                return;
        }

        peer->ibp_reconnected = 0;
        if (list_empty(&peer->ibp_conns)) {
                /* Take peer's blocked transmits to complete with error */
                list_add(&zombies, &peer->ibp_tx_queue);
                list_del_init(&peer->ibp_tx_queue);

                if (kiblnd_peer_active(peer))
                        kiblnd_unlink_peer_locked(peer);

                peer->ibp_error = error;
        } else {
                /* Can't have blocked transmits if there are connections */
                LASSERT(list_empty(&peer->ibp_tx_queue));
        }

        write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

        kiblnd_peer_notify(peer);

        if (list_empty(&zombies))
                return;

        CNETERR("Deleting messages for %s: connection failed\n",
                libcfs_nid2str(peer->ibp_nid));

        kiblnd_txlist_done(peer->ibp_ni, &zombies, -EHOSTUNREACH);
}

static void
kiblnd_connreq_done(struct kib_conn *conn, int status)
{
        struct kib_peer *peer = conn->ibc_peer;
        struct kib_tx *tx;
        struct kib_tx *tmp;
        struct list_head txs;
        unsigned long flags;
        int active;

        active = (conn->ibc_state == IBLND_CONN_ACTIVE_CONNECT);

        CDEBUG(D_NET, "%s: active(%d), version(%x), status(%d)\n",
               libcfs_nid2str(peer->ibp_nid), active,
               conn->ibc_version, status);

        LASSERT(!in_interrupt());
        LASSERT((conn->ibc_state == IBLND_CONN_ACTIVE_CONNECT &&
                 peer->ibp_connecting > 0) ||
                 (conn->ibc_state == IBLND_CONN_PASSIVE_WAIT &&
                 peer->ibp_accepting > 0));

        LIBCFS_FREE(conn->ibc_connvars, sizeof(*conn->ibc_connvars));
        conn->ibc_connvars = NULL;

        if (status) {
                /* failed to establish connection */
                kiblnd_peer_connect_failed(peer, active, status);
                kiblnd_finalise_conn(conn);
                return;
        }

        /* connection established */
        write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);

        conn->ibc_last_send = jiffies;
        kiblnd_set_conn_state(conn, IBLND_CONN_ESTABLISHED);
        kiblnd_peer_alive(peer);

        /*
         * Add conn to peer's list and nuke any dangling conns from a different
         * peer instance...
         */
        kiblnd_conn_addref(conn);              /* +1 ref for ibc_list */
        list_add(&conn->ibc_list, &peer->ibp_conns);
        peer->ibp_reconnected = 0;
        if (active)
                peer->ibp_connecting--;
        else
                peer->ibp_accepting--;

        if (!peer->ibp_version) {
                peer->ibp_version     = conn->ibc_version;
                peer->ibp_incarnation = conn->ibc_incarnation;
        }

        if (peer->ibp_version     != conn->ibc_version ||
            peer->ibp_incarnation != conn->ibc_incarnation) {
                kiblnd_close_stale_conns_locked(peer, conn->ibc_version,
                                                conn->ibc_incarnation);
                peer->ibp_version     = conn->ibc_version;
                peer->ibp_incarnation = conn->ibc_incarnation;
        }

        /* grab pending txs while I have the lock */
        list_add(&txs, &peer->ibp_tx_queue);
        list_del_init(&peer->ibp_tx_queue);

        if (!kiblnd_peer_active(peer) ||        /* peer has been deleted */
            conn->ibc_comms_error) {       /* error has happened already */
                lnet_ni_t *ni = peer->ibp_ni;

                /* start to shut down connection */
                kiblnd_close_conn_locked(conn, -ECONNABORTED);
                write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

                kiblnd_txlist_done(ni, &txs, -ECONNABORTED);

                return;
        }

        /*
         * +1 ref for myself, this connection is visible to other threads
         * now, refcount of peer:ibp_conns can be released by connection
         * close from either a different thread, or the calling of
         * kiblnd_check_sends_locked() below. See bz21911 for details.
         */
        kiblnd_conn_addref(conn);
        write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

        /* Schedule blocked txs */
        spin_lock(&conn->ibc_lock);
        list_for_each_entry_safe(tx, tmp, &txs, tx_list) {
                list_del(&tx->tx_list);

                kiblnd_queue_tx_locked(tx, conn);
        }
        kiblnd_check_sends_locked(conn);
        spin_unlock(&conn->ibc_lock);

        /* schedule blocked rxs */
        kiblnd_handle_early_rxs(conn);

        kiblnd_conn_decref(conn);
}

static void
kiblnd_reject(struct rdma_cm_id *cmid, struct kib_rej *rej)
{
        int rc;

        rc = rdma_reject(cmid, rej, sizeof(*rej));

        if (rc)
                CWARN("Error %d sending reject\n", rc);
}

static int
kiblnd_passive_connect(struct rdma_cm_id *cmid, void *priv, int priv_nob)
{
        rwlock_t *g_lock = &kiblnd_data.kib_global_lock;
        struct kib_msg *reqmsg = priv;
        struct kib_msg *ackmsg;
        struct kib_dev *ibdev;
        struct kib_peer *peer;
        struct kib_peer *peer2;
        struct kib_conn *conn;
        lnet_ni_t *ni  = NULL;
        struct kib_net *net = NULL;
        lnet_nid_t nid;
        struct rdma_conn_param cp;
        struct kib_rej rej;
        int version = IBLND_MSG_VERSION;
        unsigned long flags;
        int max_frags;
        int rc;
        struct sockaddr_in *peer_addr;

        LASSERT(!in_interrupt());

        /* cmid inherits 'context' from the corresponding listener id */
        ibdev = (struct kib_dev *)cmid->context;
        LASSERT(ibdev);

        memset(&rej, 0, sizeof(rej));
        rej.ibr_magic = IBLND_MSG_MAGIC;
        rej.ibr_why = IBLND_REJECT_FATAL;
        rej.ibr_cp.ibcp_max_msg_size = IBLND_MSG_SIZE;

        peer_addr = (struct sockaddr_in *)&cmid->route.addr.dst_addr;
        if (*kiblnd_tunables.kib_require_priv_port &&
            ntohs(peer_addr->sin_port) >= PROT_SOCK) {
                __u32 ip = ntohl(peer_addr->sin_addr.s_addr);

                CERROR("Peer's port (%pI4h:%hu) is not privileged\n",
                       &ip, ntohs(peer_addr->sin_port));
                goto failed;
        }

        if (priv_nob < offsetof(struct kib_msg, ibm_type)) {
                CERROR("Short connection request\n");
                goto failed;
        }

        /*
         * Future protocol version compatibility support!  If the
         * o2iblnd-specific protocol changes, or when LNET unifies
         * protocols over all LNDs, the initial connection will
         * negotiate a protocol version.  I trap this here to avoid
         * console errors; the reject tells the peer which protocol I
         * speak.
         */
        if (reqmsg->ibm_magic == LNET_PROTO_MAGIC ||
            reqmsg->ibm_magic == __swab32(LNET_PROTO_MAGIC))
                goto failed;
        if (reqmsg->ibm_magic == IBLND_MSG_MAGIC &&
            reqmsg->ibm_version != IBLND_MSG_VERSION &&
            reqmsg->ibm_version != IBLND_MSG_VERSION_1)
                goto failed;
        if (reqmsg->ibm_magic == __swab32(IBLND_MSG_MAGIC) &&
            reqmsg->ibm_version != __swab16(IBLND_MSG_VERSION) &&
            reqmsg->ibm_version != __swab16(IBLND_MSG_VERSION_1))
                goto failed;

        rc = kiblnd_unpack_msg(reqmsg, priv_nob);
        if (rc) {
                CERROR("Can't parse connection request: %d\n", rc);
                goto failed;
        }

        nid = reqmsg->ibm_srcnid;
        ni = lnet_net2ni(LNET_NIDNET(reqmsg->ibm_dstnid));

        if (ni) {
                net = (struct kib_net *)ni->ni_data;
                rej.ibr_incarnation = net->ibn_incarnation;
        }

        if (!ni ||                       /* no matching net */
            ni->ni_nid != reqmsg->ibm_dstnid ||   /* right NET, wrong NID! */
            net->ibn_dev != ibdev) {          /* wrong device */
                CERROR("Can't accept conn from %s on %s (%s:%d:%pI4h): bad dst nid %s\n",
                       libcfs_nid2str(nid),
                       !ni ? "NA" : libcfs_nid2str(ni->ni_nid),
                       ibdev->ibd_ifname, ibdev->ibd_nnets,
                       &ibdev->ibd_ifip,
                       libcfs_nid2str(reqmsg->ibm_dstnid));

                goto failed;
        }

       /* check time stamp as soon as possible */
        if (reqmsg->ibm_dststamp &&
            reqmsg->ibm_dststamp != net->ibn_incarnation) {
                CWARN("Stale connection request\n");
                rej.ibr_why = IBLND_REJECT_CONN_STALE;
                goto failed;
        }

        /* I can accept peer's version */
        version = reqmsg->ibm_version;

        if (reqmsg->ibm_type != IBLND_MSG_CONNREQ) {
                CERROR("Unexpected connreq msg type: %x from %s\n",
                       reqmsg->ibm_type, libcfs_nid2str(nid));
                goto failed;
        }

        if (reqmsg->ibm_u.connparams.ibcp_queue_depth >
            kiblnd_msg_queue_size(version, ni)) {
                CERROR("Can't accept conn from %s, queue depth too large: %d (<=%d wanted)\n",
                       libcfs_nid2str(nid),
                       reqmsg->ibm_u.connparams.ibcp_queue_depth,
                       kiblnd_msg_queue_size(version, ni));

                if (version == IBLND_MSG_VERSION)
                        rej.ibr_why = IBLND_REJECT_MSG_QUEUE_SIZE;

                goto failed;
        }

        max_frags = reqmsg->ibm_u.connparams.ibcp_max_frags >> IBLND_FRAG_SHIFT;
        if (max_frags > kiblnd_rdma_frags(version, ni)) {
                CWARN("Can't accept conn from %s (version %x): max message size %d is too large (%d wanted)\n",
                      libcfs_nid2str(nid), version, max_frags,
                      kiblnd_rdma_frags(version, ni));

                if (version >= IBLND_MSG_VERSION)
                        rej.ibr_why = IBLND_REJECT_RDMA_FRAGS;

                goto failed;
        } else if (max_frags < kiblnd_rdma_frags(version, ni) &&
                   !net->ibn_fmr_ps) {
                CWARN("Can't accept conn from %s (version %x): max message size %d incompatible without FMR pool (%d wanted)\n",
                      libcfs_nid2str(nid), version, max_frags,
                      kiblnd_rdma_frags(version, ni));

                if (version == IBLND_MSG_VERSION)
                        rej.ibr_why = IBLND_REJECT_RDMA_FRAGS;

                goto failed;
        }

        if (reqmsg->ibm_u.connparams.ibcp_max_msg_size > IBLND_MSG_SIZE) {
                CERROR("Can't accept %s: message size %d too big (%d max)\n",
                       libcfs_nid2str(nid),
                       reqmsg->ibm_u.connparams.ibcp_max_msg_size,
                       IBLND_MSG_SIZE);
                goto failed;
        }

        /* assume 'nid' is a new peer; create  */
        rc = kiblnd_create_peer(ni, &peer, nid);
        if (rc) {
                CERROR("Can't create peer for %s\n", libcfs_nid2str(nid));
                rej.ibr_why = IBLND_REJECT_NO_RESOURCES;
                goto failed;
        }

        /* We have validated the peer's parameters so use those */
        peer->ibp_max_frags = max_frags;
        peer->ibp_queue_depth = reqmsg->ibm_u.connparams.ibcp_queue_depth;

        write_lock_irqsave(g_lock, flags);

        peer2 = kiblnd_find_peer_locked(nid);
        if (peer2) {
                if (!peer2->ibp_version) {
                        peer2->ibp_version     = version;
                        peer2->ibp_incarnation = reqmsg->ibm_srcstamp;
                }

                /* not the guy I've talked with */
                if (peer2->ibp_incarnation != reqmsg->ibm_srcstamp ||
                    peer2->ibp_version     != version) {
                        kiblnd_close_peer_conns_locked(peer2, -ESTALE);

                        if (kiblnd_peer_active(peer2)) {
                                peer2->ibp_incarnation = reqmsg->ibm_srcstamp;
                                peer2->ibp_version = version;
                        }
                        write_unlock_irqrestore(g_lock, flags);

                        CWARN("Conn stale %s version %x/%x incarnation %llu/%llu\n",
                              libcfs_nid2str(nid), peer2->ibp_version, version,
                              peer2->ibp_incarnation, reqmsg->ibm_srcstamp);

                        kiblnd_peer_decref(peer);
                        rej.ibr_why = IBLND_REJECT_CONN_STALE;
                        goto failed;
                }

                /*
                 * Tie-break connection race in favour of the higher NID.
                 * If we keep running into a race condition multiple times,
                 * we have to assume that the connection attempt with the
                 * higher NID is stuck in a connecting state and will never
                 * recover.  As such, we pass through this if-block and let
                 * the lower NID connection win so we can move forward.
                 */
                if (peer2->ibp_connecting &&
                    nid < ni->ni_nid && peer2->ibp_races <
                    MAX_CONN_RACES_BEFORE_ABORT) {
                        peer2->ibp_races++;
                        write_unlock_irqrestore(g_lock, flags);

                        CDEBUG(D_NET, "Conn race %s\n",
                               libcfs_nid2str(peer2->ibp_nid));

                        kiblnd_peer_decref(peer);
                        rej.ibr_why = IBLND_REJECT_CONN_RACE;
                        goto failed;
                }
                if (peer2->ibp_races >= MAX_CONN_RACES_BEFORE_ABORT)
                        CNETERR("Conn race %s: unresolved after %d attempts, letting lower NID win\n",
                                libcfs_nid2str(peer2->ibp_nid),
                                MAX_CONN_RACES_BEFORE_ABORT);
                /**
                 * passive connection is allowed even this peer is waiting for
                 * reconnection.
                 */
                peer2->ibp_reconnecting = 0;
                peer2->ibp_races = 0;
                peer2->ibp_accepting++;
                kiblnd_peer_addref(peer2);

                /**
                 * Race with kiblnd_launch_tx (active connect) to create peer
                 * so copy validated parameters since we now know what the
                 * peer's limits are
                 */
                peer2->ibp_max_frags = peer->ibp_max_frags;
                peer2->ibp_queue_depth = peer->ibp_queue_depth;

                write_unlock_irqrestore(g_lock, flags);
                kiblnd_peer_decref(peer);
                peer = peer2;
        } else {
                /* Brand new peer */
                LASSERT(!peer->ibp_accepting);
                LASSERT(!peer->ibp_version &&
                        !peer->ibp_incarnation);

                peer->ibp_accepting   = 1;
                peer->ibp_version     = version;
                peer->ibp_incarnation = reqmsg->ibm_srcstamp;

                /* I have a ref on ni that prevents it being shutdown */
                LASSERT(!net->ibn_shutdown);

                kiblnd_peer_addref(peer);
                list_add_tail(&peer->ibp_list, kiblnd_nid2peerlist(nid));

                write_unlock_irqrestore(g_lock, flags);
        }

        conn = kiblnd_create_conn(peer, cmid, IBLND_CONN_PASSIVE_WAIT,
                                  version);
        if (!conn) {
                kiblnd_peer_connect_failed(peer, 0, -ENOMEM);
                kiblnd_peer_decref(peer);
                rej.ibr_why = IBLND_REJECT_NO_RESOURCES;
                goto failed;
        }

        /*
         * conn now "owns" cmid, so I return success from here on to ensure the
         * CM callback doesn't destroy cmid.
         */
        conn->ibc_incarnation      = reqmsg->ibm_srcstamp;
        conn->ibc_credits          = conn->ibc_queue_depth;
        conn->ibc_reserved_credits = conn->ibc_queue_depth;
        LASSERT(conn->ibc_credits + conn->ibc_reserved_credits +
                IBLND_OOB_MSGS(version) <= IBLND_RX_MSGS(conn));

        ackmsg = &conn->ibc_connvars->cv_msg;
        memset(ackmsg, 0, sizeof(*ackmsg));

        kiblnd_init_msg(ackmsg, IBLND_MSG_CONNACK,
                        sizeof(ackmsg->ibm_u.connparams));
        ackmsg->ibm_u.connparams.ibcp_queue_depth = conn->ibc_queue_depth;
        ackmsg->ibm_u.connparams.ibcp_max_frags = conn->ibc_max_frags << IBLND_FRAG_SHIFT;
        ackmsg->ibm_u.connparams.ibcp_max_msg_size = IBLND_MSG_SIZE;

        kiblnd_pack_msg(ni, ackmsg, version, 0, nid, reqmsg->ibm_srcstamp);

        memset(&cp, 0, sizeof(cp));
        cp.private_data = ackmsg;
        cp.private_data_len = ackmsg->ibm_nob;
        cp.responder_resources = 0;          /* No atomic ops or RDMA reads */
        cp.initiator_depth = 0;
        cp.flow_control = 1;
        cp.retry_count = *kiblnd_tunables.kib_retry_count;
        cp.rnr_retry_count = *kiblnd_tunables.kib_rnr_retry_count;

        CDEBUG(D_NET, "Accept %s\n", libcfs_nid2str(nid));

        rc = rdma_accept(cmid, &cp);
        if (rc) {
                CERROR("Can't accept %s: %d\n", libcfs_nid2str(nid), rc);
                rej.ibr_version = version;
                rej.ibr_why     = IBLND_REJECT_FATAL;

                kiblnd_reject(cmid, &rej);
                kiblnd_connreq_done(conn, rc);
                kiblnd_conn_decref(conn);
        }

        lnet_ni_decref(ni);
        return 0;

 failed:
        if (ni) {
                rej.ibr_cp.ibcp_queue_depth = kiblnd_msg_queue_size(version, ni);
                rej.ibr_cp.ibcp_max_frags = kiblnd_rdma_frags(version, ni);
                lnet_ni_decref(ni);
        }

        rej.ibr_version             = version;
        kiblnd_reject(cmid, &rej);

        return -ECONNREFUSED;
}

static void
kiblnd_check_reconnect(struct kib_conn *conn, int version,
                       __u64 incarnation, int why, struct kib_connparams *cp)
{
        rwlock_t *glock = &kiblnd_data.kib_global_lock;
        struct kib_peer *peer = conn->ibc_peer;
        char *reason;
        int msg_size = IBLND_MSG_SIZE;
        int frag_num = -1;
        int queue_dep = -1;
        bool reconnect;
        unsigned long flags;

        LASSERT(conn->ibc_state == IBLND_CONN_ACTIVE_CONNECT);
        LASSERT(peer->ibp_connecting > 0);     /* 'conn' at least */
        LASSERT(!peer->ibp_reconnecting);

        if (cp) {
                msg_size = cp->ibcp_max_msg_size;
                frag_num        = cp->ibcp_max_frags << IBLND_FRAG_SHIFT;
                queue_dep = cp->ibcp_queue_depth;
        }

        write_lock_irqsave(glock, flags);
        /**
         * retry connection if it's still needed and no other connection
         * attempts (active or passive) are in progress
         * NB: reconnect is still needed even when ibp_tx_queue is
         * empty if ibp_version != version because reconnect may be
         * initiated by kiblnd_query()
         */
        reconnect = (!list_empty(&peer->ibp_tx_queue) ||
                     peer->ibp_version != version) &&
                    peer->ibp_connecting == 1 &&
                    !peer->ibp_accepting;
        if (!reconnect) {
                reason = "no need";
                goto out;
        }

        switch (why) {
        default:
                reason = "Unknown";
                break;

        case IBLND_REJECT_RDMA_FRAGS: {
                struct lnet_ioctl_config_lnd_tunables *tunables;

                if (!cp) {
                        reason = "can't negotiate max frags";
                        goto out;
                }
                tunables = peer->ibp_ni->ni_lnd_tunables;
                if (!tunables->lt_tun_u.lt_o2ib.lnd_map_on_demand) {
                        reason = "map_on_demand must be enabled";
                        goto out;
                }
                if (conn->ibc_max_frags <= frag_num) {
                        reason = "unsupported max frags";
                        goto out;
                }

                peer->ibp_max_frags = frag_num;
                reason = "rdma fragments";
                break;
        }
        case IBLND_REJECT_MSG_QUEUE_SIZE:
                if (!cp) {
                        reason = "can't negotiate queue depth";
                        goto out;
                }
                if (conn->ibc_queue_depth <= queue_dep) {
                        reason = "unsupported queue depth";
                        goto out;
                }

                peer->ibp_queue_depth = queue_dep;
                reason = "queue depth";
                break;

        case IBLND_REJECT_CONN_STALE:
                reason = "stale";
                break;

        case IBLND_REJECT_CONN_RACE:
                reason = "conn race";
                break;

        case IBLND_REJECT_CONN_UNCOMPAT:
                reason = "version negotiation";
                break;
        }

        conn->ibc_reconnect = 1;
        peer->ibp_reconnecting = 1;
        peer->ibp_version = version;
        if (incarnation)
                peer->ibp_incarnation = incarnation;
out:
        write_unlock_irqrestore(glock, flags);

        CNETERR("%s: %s (%s), %x, %x, msg_size: %d, queue_depth: %d/%d, max_frags: %d/%d\n",
                libcfs_nid2str(peer->ibp_nid),
                reconnect ? "reconnect" : "don't reconnect",
                reason, IBLND_MSG_VERSION, version, msg_size,
                conn->ibc_queue_depth, queue_dep,
                conn->ibc_max_frags, frag_num);
        /**
         * if conn::ibc_reconnect is TRUE, connd will reconnect to the peer
         * while destroying the zombie
         */
}

static void
kiblnd_rejected(struct kib_conn *conn, int reason, void *priv, int priv_nob)
{
        struct kib_peer *peer = conn->ibc_peer;

        LASSERT(!in_interrupt());
        LASSERT(conn->ibc_state == IBLND_CONN_ACTIVE_CONNECT);

        switch (reason) {
        case IB_CM_REJ_STALE_CONN:
                kiblnd_check_reconnect(conn, IBLND_MSG_VERSION, 0,
                                       IBLND_REJECT_CONN_STALE, NULL);
                break;

        case IB_CM_REJ_INVALID_SERVICE_ID:
                CNETERR("%s rejected: no listener at %d\n",
                        libcfs_nid2str(peer->ibp_nid),
                        *kiblnd_tunables.kib_service);
                break;

        case IB_CM_REJ_CONSUMER_DEFINED:
                if (priv_nob >= offsetof(struct kib_rej, ibr_padding)) {
                        struct kib_rej *rej = priv;
                        struct kib_connparams *cp = NULL;
                        int flip = 0;
                        __u64 incarnation = -1;

                        /* NB. default incarnation is -1 because:
                         * a) V1 will ignore dst incarnation in connreq.
                         * b) V2 will provide incarnation while rejecting me,
                         *    -1 will be overwrote.
                         *
                         * if I try to connect to a V1 peer with V2 protocol,
                         * it rejected me then upgrade to V2, I have no idea
                         * about the upgrading and try to reconnect with V1,
                         * in this case upgraded V2 can find out I'm trying to
                         * talk to the old guy and reject me(incarnation is -1).
                         */

                        if (rej->ibr_magic == __swab32(IBLND_MSG_MAGIC) ||
                            rej->ibr_magic == __swab32(LNET_PROTO_MAGIC)) {
                                __swab32s(&rej->ibr_magic);
                                __swab16s(&rej->ibr_version);
                                flip = 1;
                        }

                        if (priv_nob >= sizeof(struct kib_rej) &&
                            rej->ibr_version > IBLND_MSG_VERSION_1) {
                                /*
                                 * priv_nob is always 148 in current version
                                 * of OFED, so we still need to check version.
                                 * (define of IB_CM_REJ_PRIVATE_DATA_SIZE)
                                 */
                                cp = &rej->ibr_cp;

                                if (flip) {
                                        __swab64s(&rej->ibr_incarnation);
                                        __swab16s(&cp->ibcp_queue_depth);
                                        __swab16s(&cp->ibcp_max_frags);
                                        __swab32s(&cp->ibcp_max_msg_size);
                                }

                                incarnation = rej->ibr_incarnation;
                        }

                        if (rej->ibr_magic != IBLND_MSG_MAGIC &&
                            rej->ibr_magic != LNET_PROTO_MAGIC) {
                                CERROR("%s rejected: consumer defined fatal error\n",
                                       libcfs_nid2str(peer->ibp_nid));
                                break;
                        }

                        if (rej->ibr_version != IBLND_MSG_VERSION &&
                            rej->ibr_version != IBLND_MSG_VERSION_1) {
                                CERROR("%s rejected: o2iblnd version %x error\n",
                                       libcfs_nid2str(peer->ibp_nid),
                                       rej->ibr_version);
                                break;
                        }

                        if (rej->ibr_why     == IBLND_REJECT_FATAL &&
                            rej->ibr_version == IBLND_MSG_VERSION_1) {
                                CDEBUG(D_NET, "rejected by old version peer %s: %x\n",
                                       libcfs_nid2str(peer->ibp_nid), rej->ibr_version);

                                if (conn->ibc_version != IBLND_MSG_VERSION_1)
                                        rej->ibr_why = IBLND_REJECT_CONN_UNCOMPAT;
                        }

                        switch (rej->ibr_why) {
                        case IBLND_REJECT_CONN_RACE:
                        case IBLND_REJECT_CONN_STALE:
                        case IBLND_REJECT_CONN_UNCOMPAT:
                        case IBLND_REJECT_MSG_QUEUE_SIZE:
                        case IBLND_REJECT_RDMA_FRAGS:
                                kiblnd_check_reconnect(conn, rej->ibr_version,
                                                       incarnation,
                                                       rej->ibr_why, cp);
                                break;

                        case IBLND_REJECT_NO_RESOURCES:
                                CERROR("%s rejected: o2iblnd no resources\n",
                                       libcfs_nid2str(peer->ibp_nid));
                                break;

                        case IBLND_REJECT_FATAL:
                                CERROR("%s rejected: o2iblnd fatal error\n",
                                       libcfs_nid2str(peer->ibp_nid));
                                break;

                        default:
                                CERROR("%s rejected: o2iblnd reason %d\n",
                                       libcfs_nid2str(peer->ibp_nid),
                                       rej->ibr_why);
                                break;
                        }
                        break;
                }
                /* fall through */
        default:
                CNETERR("%s rejected: reason %d, size %d\n",
                        libcfs_nid2str(peer->ibp_nid), reason, priv_nob);
                break;
        }

        kiblnd_connreq_done(conn, -ECONNREFUSED);
}

static void
kiblnd_check_connreply(struct kib_conn *conn, void *priv, int priv_nob)
{
        struct kib_peer *peer = conn->ibc_peer;
        lnet_ni_t *ni = peer->ibp_ni;
        struct kib_net *net = ni->ni_data;
        struct kib_msg *msg = priv;
        int ver = conn->ibc_version;
        int rc = kiblnd_unpack_msg(msg, priv_nob);
        unsigned long flags;

        LASSERT(net);

        if (rc) {
                CERROR("Can't unpack connack from %s: %d\n",
                       libcfs_nid2str(peer->ibp_nid), rc);
                goto failed;
        }

        if (msg->ibm_type != IBLND_MSG_CONNACK) {
                CERROR("Unexpected message %d from %s\n",
                       msg->ibm_type, libcfs_nid2str(peer->ibp_nid));
                rc = -EPROTO;
                goto failed;
        }

        if (ver != msg->ibm_version) {
                CERROR("%s replied version %x is different with requested version %x\n",
                       libcfs_nid2str(peer->ibp_nid), msg->ibm_version, ver);
                rc = -EPROTO;
                goto failed;
        }

        if (msg->ibm_u.connparams.ibcp_queue_depth >
            conn->ibc_queue_depth) {
                CERROR("%s has incompatible queue depth %d (<=%d wanted)\n",
                       libcfs_nid2str(peer->ibp_nid),
                       msg->ibm_u.connparams.ibcp_queue_depth,
                       conn->ibc_queue_depth);
                rc = -EPROTO;
                goto failed;
        }

        if ((msg->ibm_u.connparams.ibcp_max_frags >> IBLND_FRAG_SHIFT) >
            conn->ibc_max_frags) {
                CERROR("%s has incompatible max_frags %d (<=%d wanted)\n",
                       libcfs_nid2str(peer->ibp_nid),
                       msg->ibm_u.connparams.ibcp_max_frags >> IBLND_FRAG_SHIFT,
                       conn->ibc_max_frags);
                rc = -EPROTO;
                goto failed;
        }

        if (msg->ibm_u.connparams.ibcp_max_msg_size > IBLND_MSG_SIZE) {
                CERROR("%s max message size %d too big (%d max)\n",
                       libcfs_nid2str(peer->ibp_nid),
                       msg->ibm_u.connparams.ibcp_max_msg_size,
                       IBLND_MSG_SIZE);
                rc = -EPROTO;
                goto failed;
        }

        read_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
        if (msg->ibm_dstnid == ni->ni_nid &&
            msg->ibm_dststamp == net->ibn_incarnation)
                rc = 0;
        else
                rc = -ESTALE;
        read_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

        if (rc) {
                CERROR("Bad connection reply from %s, rc = %d, version: %x max_frags: %d\n",
                       libcfs_nid2str(peer->ibp_nid), rc,
                       msg->ibm_version, msg->ibm_u.connparams.ibcp_max_frags);
                goto failed;
        }

        conn->ibc_incarnation = msg->ibm_srcstamp;
        conn->ibc_credits = msg->ibm_u.connparams.ibcp_queue_depth;
        conn->ibc_reserved_credits = msg->ibm_u.connparams.ibcp_queue_depth;
        conn->ibc_queue_depth = msg->ibm_u.connparams.ibcp_queue_depth;
        conn->ibc_max_frags = msg->ibm_u.connparams.ibcp_max_frags >> IBLND_FRAG_SHIFT;
        LASSERT(conn->ibc_credits + conn->ibc_reserved_credits +
                IBLND_OOB_MSGS(ver) <= IBLND_RX_MSGS(conn));

        kiblnd_connreq_done(conn, 0);
        return;

 failed:
        /*
         * NB My QP has already established itself, so I handle anything going
         * wrong here by setting ibc_comms_error.
         * kiblnd_connreq_done(0) moves the conn state to ESTABLISHED, but then
         * immediately tears it down.
         */
        LASSERT(rc);
        conn->ibc_comms_error = rc;
        kiblnd_connreq_done(conn, 0);
}

static int
kiblnd_active_connect(struct rdma_cm_id *cmid)
{
        struct kib_peer *peer = (struct kib_peer *)cmid->context;
        struct kib_conn *conn;
        struct kib_msg *msg;
        struct rdma_conn_param cp;
        int version;
        __u64 incarnation;
        unsigned long flags;
        int rc;

        read_lock_irqsave(&kiblnd_data.kib_global_lock, flags);

        incarnation = peer->ibp_incarnation;
        version = !peer->ibp_version ? IBLND_MSG_VERSION :
                                       peer->ibp_version;

        read_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);

        conn = kiblnd_create_conn(peer, cmid, IBLND_CONN_ACTIVE_CONNECT,
                                  version);
        if (!conn) {
                kiblnd_peer_connect_failed(peer, 1, -ENOMEM);
                kiblnd_peer_decref(peer); /* lose cmid's ref */
                return -ENOMEM;
        }

        /*
         * conn "owns" cmid now, so I return success from here on to ensure the
         * CM callback doesn't destroy cmid. conn also takes over cmid's ref
         * on peer
         */
        msg = &conn->ibc_connvars->cv_msg;

        memset(msg, 0, sizeof(*msg));
        kiblnd_init_msg(msg, IBLND_MSG_CONNREQ, sizeof(msg->ibm_u.connparams));
        msg->ibm_u.connparams.ibcp_queue_depth = conn->ibc_queue_depth;
        msg->ibm_u.connparams.ibcp_max_frags = conn->ibc_max_frags << IBLND_FRAG_SHIFT;
        msg->ibm_u.connparams.ibcp_max_msg_size = IBLND_MSG_SIZE;

        kiblnd_pack_msg(peer->ibp_ni, msg, version,
                        0, peer->ibp_nid, incarnation);

        memset(&cp, 0, sizeof(cp));
        cp.private_data = msg;
        cp.private_data_len    = msg->ibm_nob;
        cp.responder_resources = 0;          /* No atomic ops or RDMA reads */
        cp.initiator_depth     = 0;
        cp.flow_control        = 1;
        cp.retry_count         = *kiblnd_tunables.kib_retry_count;
        cp.rnr_retry_count     = *kiblnd_tunables.kib_rnr_retry_count;

        LASSERT(cmid->context == (void *)conn);
        LASSERT(conn->ibc_cmid == cmid);

        rc = rdma_connect(cmid, &cp);
        if (rc) {
                CERROR("Can't connect to %s: %d\n",
                       libcfs_nid2str(peer->ibp_nid), rc);
                kiblnd_connreq_done(conn, rc);
                kiblnd_conn_decref(conn);
        }

        return 0;
}

int
kiblnd_cm_callback(struct rdma_cm_id *cmid, struct rdma_cm_event *event)
{
        struct kib_peer *peer;
        struct kib_conn *conn;
        int rc;

        switch (event->event) {
        default:
                CERROR("Unexpected event: %d, status: %d\n",
                       event->event, event->status);
                LBUG();

        case RDMA_CM_EVENT_CONNECT_REQUEST:
                /* destroy cmid on failure */
                rc = kiblnd_passive_connect(cmid,
                                            (void *)KIBLND_CONN_PARAM(event),
                                            KIBLND_CONN_PARAM_LEN(event));
                CDEBUG(D_NET, "connreq: %d\n", rc);
                return rc;

        case RDMA_CM_EVENT_ADDR_ERROR:
                peer = (struct kib_peer *)cmid->context;
                CNETERR("%s: ADDR ERROR %d\n",
                        libcfs_nid2str(peer->ibp_nid), event->status);
                kiblnd_peer_connect_failed(peer, 1, -EHOSTUNREACH);
                kiblnd_peer_decref(peer);
                return -EHOSTUNREACH;      /* rc destroys cmid */

        case RDMA_CM_EVENT_ADDR_RESOLVED:
                peer = (struct kib_peer *)cmid->context;

                CDEBUG(D_NET, "%s Addr resolved: %d\n",
                       libcfs_nid2str(peer->ibp_nid), event->status);

                if (event->status) {
                        CNETERR("Can't resolve address for %s: %d\n",
                                libcfs_nid2str(peer->ibp_nid), event->status);
                        rc = event->status;
                } else {
                        rc = rdma_resolve_route(
                                cmid, *kiblnd_tunables.kib_timeout * 1000);
                        if (!rc)
                                return 0;
                        /* Can't initiate route resolution */
                        CERROR("Can't resolve route for %s: %d\n",