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LU-7734 lnet: handle N NIs to 1 LND peer
[fs/lustre-release.git] / lnet / klnds / o2iblnd / o2iblnd_cb.c
index de402e7..41b9cdb 100644 (file)
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */
@@ -27,7 +23,7 @@
  * Copyright (c) 2007, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2012, Intel Corporation.
+ * Copyright (c) 2012, 2016, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
 
 #include "o2iblnd.h"
 
+#define MAX_CONN_RACES_BEFORE_ABORT 20
+
 static void kiblnd_peer_alive(kib_peer_t *peer);
 static void kiblnd_peer_connect_failed(kib_peer_t *peer, int active, int error);
-static void kiblnd_check_sends(kib_conn_t *conn);
 static void kiblnd_init_tx_msg(lnet_ni_t *ni, kib_tx_t *tx,
                               int type, int body_nob);
 static int kiblnd_init_rdma(kib_conn_t *conn, kib_tx_t *tx, int type,
                            int resid, kib_rdma_desc_t *dstrd, __u64 dstcookie);
 static void kiblnd_queue_tx_locked(kib_tx_t *tx, kib_conn_t *conn);
 static void kiblnd_queue_tx(kib_tx_t *tx, kib_conn_t *conn);
+static void kiblnd_unmap_tx(lnet_ni_t *ni, kib_tx_t *tx);
+static void kiblnd_check_sends_locked(kib_conn_t *conn);
 
-static void
+void
 kiblnd_tx_done (lnet_ni_t *ni, kib_tx_t *tx)
 {
        lnet_msg_t *lntmsg[2];
@@ -117,7 +116,7 @@ kiblnd_get_idle_tx(lnet_ni_t *ni, lnet_nid_t target)
        kib_tx_t                *tx;
        kib_tx_poolset_t        *tps;
 
-       tps = net->ibn_tx_ps[lnet_cpt_of_nid(target)];
+       tps = net->ibn_tx_ps[lnet_cpt_of_nid(target, ni)];
        node = kiblnd_pool_alloc_node(&tps->tps_poolset);
         if (node == NULL)
                 return NULL;
@@ -131,7 +130,6 @@ kiblnd_get_idle_tx(lnet_ni_t *ni, lnet_nid_t target)
         LASSERT (tx->tx_conn == NULL);
         LASSERT (tx->tx_lntmsg[0] == NULL);
         LASSERT (tx->tx_lntmsg[1] == NULL);
-        LASSERT (tx->tx_u.pmr == NULL);
         LASSERT (tx->tx_nfrags == 0);
 
         return tx;
@@ -158,7 +156,7 @@ kiblnd_post_rx (kib_rx_t *rx, int credit)
        kib_conn_t         *conn = rx->rx_conn;
        kib_net_t          *net = conn->ibc_peer->ibp_ni->ni_data;
        struct ib_recv_wr  *bad_wrq = NULL;
-       struct ib_mr       *mr;
+       struct ib_mr       *mr = conn->ibc_hdev->ibh_mrs;
        int                 rc;
 
        LASSERT (net != NULL);
@@ -166,9 +164,7 @@ kiblnd_post_rx (kib_rx_t *rx, int credit)
        LASSERT (credit == IBLND_POSTRX_NO_CREDIT ||
                 credit == IBLND_POSTRX_PEER_CREDIT ||
                 credit == IBLND_POSTRX_RSRVD_CREDIT);
-
-       mr = kiblnd_find_dma_mr(conn->ibc_hdev, rx->rx_msgaddr, IBLND_MSG_SIZE);
-       LASSERT (mr != NULL);
+       LASSERT(mr != NULL);
 
         rx->rx_sge.lkey   = mr->lkey;
         rx->rx_sge.addr   = rx->rx_msgaddr;
@@ -189,34 +185,40 @@ kiblnd_post_rx (kib_rx_t *rx, int credit)
 
         rx->rx_nob = -1;                        /* flag posted */
 
-        rc = ib_post_recv(conn->ibc_cmid->qp, &rx->rx_wrq, &bad_wrq);
-        if (rc != 0) {
-                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;
-        }
+       /* 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 != 0)) {
+               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 */
-                return rc;
+       if (conn->ibc_state < IBLND_CONN_ESTABLISHED) /* Initial post */
+               goto out;
 
-        if (rc != 0) {
-                kiblnd_close_conn(conn, rc);
-                kiblnd_drop_rx(rx);             /* No more posts for this rx */
-                return rc;
-        }
+       if (unlikely(rc != 0)) {
+               kiblnd_close_conn(conn, rc);
+               kiblnd_drop_rx(rx);     /* No more posts for this rx */
+               goto out;
+       }
 
-        if (credit == IBLND_POSTRX_NO_CREDIT)
-                return 0;
+       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);
 
-       kiblnd_check_sends(conn);
-       return 0;
+out:
+       kiblnd_conn_decref(conn);
+       return rc;
 }
 
 static kib_tx_t *
@@ -257,7 +259,7 @@ kiblnd_handle_completion(kib_conn_t *conn, int txtype, int status, __u64 cookie)
        if (tx == NULL) {
                spin_unlock(&conn->ibc_lock);
 
-                CWARN("Unmatched completion type %x cookie "LPX64" from %s\n",
+               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;
@@ -325,19 +327,19 @@ kiblnd_handle_rx (kib_rx_t *rx)
                spin_lock(&conn->ibc_lock);
 
                if (conn->ibc_credits + credits >
-                   IBLND_MSG_QUEUE_SIZE(conn->ibc_version)) {
+                   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,
-                               IBLND_MSG_QUEUE_SIZE(conn->ibc_version));
+                       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;
-                }
+                       kiblnd_close_conn(conn, -EPROTO);
+                       kiblnd_post_rx(rx, IBLND_POSTRX_NO_CREDIT);
+                       return;
+               }
 
                 conn->ibc_credits += credits;
 
@@ -346,8 +348,8 @@ kiblnd_handle_rx (kib_rx_t *rx)
                     !IBLND_OOB_CAPABLE(conn->ibc_version)) /* v1 only */
                         conn->ibc_outstanding_credits++;
 
+               kiblnd_check_sends_locked(conn);
                spin_unlock(&conn->ibc_lock);
-                kiblnd_check_sends(conn);
         }
 
         switch (msg->ibm_type) {
@@ -558,56 +560,10 @@ kiblnd_kvaddr_to_page (unsigned long vaddr)
 }
 
 static int
-kiblnd_fmr_map_tx(kib_net_t *net, kib_tx_t *tx, kib_rdma_desc_t *rd, int nob)
+kiblnd_fmr_map_tx(kib_net_t *net, kib_tx_t *tx, kib_rdma_desc_t *rd, __u32 nob)
 {
        kib_hca_dev_t           *hdev;
-       __u64                   *pages = tx->tx_pages;
        kib_fmr_poolset_t       *fps;
-       int                     npages;
-       int                     size;
-       int                     cpt;
-       int                     rc;
-       int                     i;
-
-       LASSERT(tx->tx_pool != NULL);
-       LASSERT(tx->tx_pool->tpo_pool.po_owner != NULL);
-
-       hdev  = tx->tx_pool->tpo_hdev;
-
-        for (i = 0, npages = 0; i < rd->rd_nfrags; i++) {
-                for (size = 0; size <  rd->rd_frags[i].rf_nob;
-                               size += hdev->ibh_page_size) {
-                        pages[npages ++] = (rd->rd_frags[i].rf_addr &
-                                            hdev->ibh_page_mask) + size;
-                }
-        }
-
-       cpt = tx->tx_pool->tpo_pool.po_owner->ps_cpt;
-
-       fps = net->ibn_fmr_ps[cpt];
-       rc = kiblnd_fmr_pool_map(fps, pages, npages, 0, &tx->tx_u.fmr);
-        if (rc != 0) {
-                CERROR ("Can't map %d pages: %d\n", npages, 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 = (rd != tx->tx_rd) ? tx->tx_u.fmr.fmr_pfmr->fmr->rkey :
-                                         tx->tx_u.fmr.fmr_pfmr->fmr->lkey;
-        rd->rd_frags[0].rf_addr &= ~hdev->ibh_page_mask;
-        rd->rd_frags[0].rf_nob   = nob;
-        rd->rd_nfrags = 1;
-
-        return 0;
-}
-
-static int
-kiblnd_pmr_map_tx(kib_net_t *net, kib_tx_t *tx, kib_rdma_desc_t *rd, int nob)
-{
-       kib_hca_dev_t           *hdev;
-       kib_pmr_poolset_t       *pps;
-       __u64                   iova;
        int                     cpt;
        int                     rc;
 
@@ -615,44 +571,34 @@ kiblnd_pmr_map_tx(kib_net_t *net, kib_tx_t *tx, kib_rdma_desc_t *rd, int nob)
        LASSERT(tx->tx_pool->tpo_pool.po_owner != NULL);
 
        hdev = tx->tx_pool->tpo_hdev;
-
-       iova = rd->rd_frags[0].rf_addr & ~hdev->ibh_page_mask;
-
        cpt = tx->tx_pool->tpo_pool.po_owner->ps_cpt;
 
-       pps = net->ibn_pmr_ps[cpt];
-       rc = kiblnd_pmr_pool_map(pps, hdev, rd, &iova, &tx->tx_u.pmr);
-        if (rc != 0) {
-                CERROR("Failed to create MR by phybuf: %d\n", rc);
-                return rc;
-        }
+       fps = net->ibn_fmr_ps[cpt];
+       rc = kiblnd_fmr_pool_map(fps, tx, rd, nob, 0, &tx->fmr);
+       if (rc != 0) {
+               CERROR("Can't map %u pages: %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 = (rd != tx->tx_rd) ? tx->tx_u.pmr->pmr_mr->rkey :
-                                         tx->tx_u.pmr->pmr_mr->lkey;
-        rd->rd_nfrags = 1;
-        rd->rd_frags[0].rf_addr = iova;
-        rd->rd_frags[0].rf_nob  = nob;
+       /* 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;
+       return 0;
 }
 
-void
+static void
 kiblnd_unmap_tx(lnet_ni_t *ni, kib_tx_t *tx)
 {
        kib_net_t  *net = ni->ni_data;
 
        LASSERT(net != NULL);
 
-       if (net->ibn_fmr_ps != NULL && tx->tx_u.fmr.fmr_pfmr != NULL) {
-               kiblnd_fmr_pool_unmap(&tx->tx_u.fmr, tx->tx_status);
-               tx->tx_u.fmr.fmr_pfmr = NULL;
-
-       } else if (net->ibn_pmr_ps != NULL && tx->tx_u.pmr != NULL) {
-               kiblnd_pmr_pool_unmap(tx->tx_u.pmr);
-               tx->tx_u.pmr = NULL;
-       }
+       if (net->ibn_fmr_ps != NULL)
+               kiblnd_fmr_pool_unmap(&tx->fmr, tx->tx_status);
 
         if (tx->tx_nfrags != 0) {
                 kiblnd_dma_unmap_sg(tx->tx_pool->tpo_hdev->ibh_ibdev,
@@ -661,24 +607,22 @@ kiblnd_unmap_tx(lnet_ni_t *ni, kib_tx_t *tx)
         }
 }
 
-int
-kiblnd_map_tx(lnet_ni_t *ni, kib_tx_t *tx,
-              kib_rdma_desc_t *rd, int nfrags)
+static int
+kiblnd_map_tx(lnet_ni_t *ni, kib_tx_t *tx, kib_rdma_desc_t *rd, int nfrags)
 {
-        kib_hca_dev_t      *hdev  = tx->tx_pool->tpo_hdev;
-        kib_net_t          *net   = ni->ni_data;
-        struct ib_mr       *mr    = NULL;
-        __u32               nob;
-        int                 i;
+       kib_net_t     *net   = ni->ni_data;
+       kib_hca_dev_t *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;
+       tx->tx_nfrags = nfrags;
 
-        rd->rd_nfrags =
-                kiblnd_dma_map_sg(hdev->ibh_ibdev,
-                                  tx->tx_frags, tx->tx_nfrags, tx->tx_dmadir);
+       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(
@@ -688,18 +632,17 @@ kiblnd_map_tx(lnet_ni_t *ni, kib_tx_t *tx,
                 nob += rd->rd_frags[i].rf_nob;
         }
 
-        /* looking for pre-mapping MR */
-        mr = kiblnd_find_rd_dma_mr(hdev, rd);
-        if (mr != NULL) {
-                /* found pre-mapping MR */
-                rd->rd_key = (rd != tx->tx_rd) ? mr->rkey : mr->lkey;
-                return 0;
-        }
+       mr = kiblnd_find_rd_dma_mr(ni, rd,
+                                  (tx->tx_conn != NULL) ?
+                                  tx->tx_conn->ibc_max_frags : -1);
+       if (mr != NULL) {
+               /* found pre-mapping MR */
+               rd->rd_key = (rd != tx->tx_rd) ? mr->rkey : mr->lkey;
+               return 0;
+       }
 
        if (net->ibn_fmr_ps != NULL)
                return kiblnd_fmr_map_tx(net, tx, rd, nob);
-       else if (net->ibn_pmr_ps != NULL)
-               return kiblnd_pmr_map_tx(net, tx, rd, nob);
 
        return -EINVAL;
 }
@@ -707,7 +650,7 @@ kiblnd_map_tx(lnet_ni_t *ni, kib_tx_t *tx,
 
 static int
 kiblnd_setup_rd_iov(lnet_ni_t *ni, kib_tx_t *tx, kib_rdma_desc_t *rd,
-                    unsigned int niov, struct iovec *iov, int offset, int nob)
+                   unsigned int niov, struct kvec *iov, int offset, int nob)
 {
         kib_net_t          *net = ni->ni_data;
         struct page        *page;
@@ -743,7 +686,11 @@ kiblnd_setup_rd_iov(lnet_ni_t *ni, kib_tx_t *tx, kib_rdma_desc_t *rd,
                 fragnob = min(fragnob, (int)PAGE_SIZE - page_offset);
 
                 sg_set_page(sg, page, fragnob, page_offset);
-                sg++;
+               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;
@@ -785,9 +732,13 @@ kiblnd_setup_rd_kiov (lnet_ni_t *ni, kib_tx_t *tx, kib_rdma_desc_t *rd,
 
                 fragnob = min((int)(kiov->kiov_len - offset), nob);
 
-                sg_set_page(sg, kiov->kiov_page, fragnob,
-                            kiov->kiov_offset + offset);
-                sg++;
+               sg_set_page(sg, kiov->kiov_page, fragnob,
+                           kiov->kiov_offset + offset);
+               sg = sg_next(sg);
+               if (!sg) {
+                       CERROR("lacking enough sg entries to map tx\n");
+                       return -EFAULT;
+               }
 
                 offset = 0;
                 kiov++;
@@ -804,23 +755,24 @@ __must_hold(&conn->ibc_lock)
 {
         kib_msg_t         *msg = tx->tx_msg;
         kib_peer_t        *peer = conn->ibc_peer;
+       struct lnet_ni    *ni = peer->ibp_ni;
         int                ver = conn->ibc_version;
         int                rc;
         int                done;
-        struct ib_send_wr *bad_wrq;
 
-        LASSERT (tx->tx_queued);
-        /* We rely on this for QP sizing */
-        LASSERT (tx->tx_nwrq > 0);
-        LASSERT (tx->tx_nwrq <= 1 + IBLND_RDMA_FRAGS(ver));
+       LASSERT(tx->tx_queued);
+       /* We rely on this for QP sizing */
+       LASSERT(tx->tx_nwrq > 0);
+       LASSERT(tx->tx_nwrq <= 1 + conn->ibc_max_frags);
 
-        LASSERT (credit == 0 || credit == 1);
-        LASSERT (conn->ibc_outstanding_credits >= 0);
-        LASSERT (conn->ibc_outstanding_credits <= IBLND_MSG_QUEUE_SIZE(ver));
-        LASSERT (conn->ibc_credits >= 0);
-        LASSERT (conn->ibc_credits <= IBLND_MSG_QUEUE_SIZE(ver));
+       LASSERT(credit == 0 || 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 == IBLND_CONCURRENT_SENDS(ver)) {
+       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));
@@ -849,9 +801,9 @@ __must_hold(&conn->ibc_lock)
             (!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 will queue NOOP again when
-                 * posted NOOPs complete */
+               /* 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);
@@ -887,9 +839,28 @@ __must_hold(&conn->ibc_lock)
                 /* close_conn will launch failover */
                 rc = -ENETDOWN;
         } else {
-                rc = ib_post_send(conn->ibc_cmid->qp,
-                                  tx->tx_wrq, &bad_wrq);
-        }
+               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 *wr  = &tx->tx_wrq[0].wr;
+
+               if (frd != NULL) {
+                       if (!frd->frd_valid) {
+                               wr = &frd->frd_inv_wr.wr;
+                               wr->next = &frd->frd_fastreg_wr.wr;
+                       } else {
+                               wr = &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, wr, &bad);
+       }
 
         conn->ibc_last_send = jiffies;
 
@@ -932,7 +903,7 @@ __must_hold(&conn->ibc_lock)
 }
 
 static void
-kiblnd_check_sends (kib_conn_t *conn)
+kiblnd_check_sends_locked(kib_conn_t *conn)
 {
         int        ver = conn->ibc_version;
         lnet_ni_t *ni = conn->ibc_peer->ibp_ni;
@@ -945,9 +916,8 @@ kiblnd_check_sends (kib_conn_t *conn)
                 return;
         }
 
-       spin_lock(&conn->ibc_lock);
-
-        LASSERT (conn->ibc_nsends_posted <= IBLND_CONCURRENT_SENDS(ver));
+       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);
@@ -973,8 +943,6 @@ kiblnd_check_sends (kib_conn_t *conn)
                         kiblnd_queue_tx_locked(tx, conn);
         }
 
-        kiblnd_conn_addref(conn); /* 1 ref for me.... (see b21911) */
-
         for (;;) {
                 int credit;
 
@@ -997,10 +965,6 @@ kiblnd_check_sends (kib_conn_t *conn)
                 if (kiblnd_post_tx_locked(conn, tx, credit) != 0)
                         break;
         }
-
-       spin_unlock(&conn->ibc_lock);
-
-       kiblnd_conn_decref(conn); /* ...until here */
 }
 
 static void
@@ -1014,7 +978,7 @@ kiblnd_tx_complete (kib_tx_t *tx, int status)
 
         if (failed) {
                 if (conn->ibc_state == IBLND_CONN_ESTABLISHED)
-                        CNETERR("Tx -> %s cookie "LPX64
+                       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,
@@ -1046,50 +1010,44 @@ kiblnd_tx_complete (kib_tx_t *tx, int status)
         if (idle)
                list_del(&tx->tx_list);
 
-        kiblnd_conn_addref(conn);               /* 1 ref for me.... */
-
+       kiblnd_check_sends_locked(conn);
        spin_unlock(&conn->ibc_lock);
 
         if (idle)
                 kiblnd_tx_done(conn->ibc_peer->ibp_ni, tx);
-
-        kiblnd_check_sends(conn);
-
-        kiblnd_conn_decref(conn);               /* ...until here */
 }
 
 static void
 kiblnd_init_tx_msg (lnet_ni_t *ni, kib_tx_t *tx, int type, int body_nob)
 {
-        kib_hca_dev_t     *hdev = tx->tx_pool->tpo_hdev;
-        struct ib_sge     *sge = &tx->tx_sge[tx->tx_nwrq];
-        struct ib_send_wr *wrq = &tx->tx_wrq[tx->tx_nwrq];
-        int                nob = offsetof (kib_msg_t, ibm_u) + body_nob;
-        struct ib_mr      *mr;
+       kib_hca_dev_t *hdev = tx->tx_pool->tpo_hdev;
+       struct ib_sge *sge = &tx->tx_sge[tx->tx_nwrq];
+       struct ib_rdma_wr *wrq;
+       int nob = offsetof(kib_msg_t, 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(tx->tx_nwrq >= 0);
+       LASSERT(tx->tx_nwrq < IBLND_MAX_RDMA_FRAGS + 1);
+       LASSERT(nob <= IBLND_MSG_SIZE);
+       LASSERT(mr != NULL);
 
         kiblnd_init_msg(tx->tx_msg, type, body_nob);
 
-        mr = kiblnd_find_dma_mr(hdev, tx->tx_msgaddr, nob);
-        LASSERT (mr != NULL);
-
         sge->lkey   = mr->lkey;
         sge->addr   = tx->tx_msgaddr;
         sge->length = nob;
 
-        memset(wrq, 0, sizeof(*wrq));
+       wrq = &tx->tx_wrq[tx->tx_nwrq];
+       memset(wrq, 0, sizeof(*wrq));
 
-        wrq->next       = NULL;
-        wrq->wr_id      = kiblnd_ptr2wreqid(tx, IBLND_WID_TX);
-        wrq->sg_list    = sge;
-        wrq->num_sge    = 1;
-        wrq->opcode     = IB_WR_SEND;
-        wrq->send_flags = IB_SEND_SIGNALED;
+       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++;
+       tx->tx_nwrq++;
 }
 
 static int
@@ -1099,7 +1057,7 @@ kiblnd_init_rdma(kib_conn_t *conn, kib_tx_t *tx, int type,
        kib_msg_t         *ibmsg = tx->tx_msg;
        kib_rdma_desc_t   *srcrd = tx->tx_rd;
        struct ib_sge     *sge = &tx->tx_sge[0];
-       struct ib_send_wr *wrq = &tx->tx_wrq[0];
+       struct ib_rdma_wr *wrq;
        int                rc  = resid;
        int                srcidx;
        int                dstidx;
@@ -1125,16 +1083,16 @@ kiblnd_init_rdma(kib_conn_t *conn, kib_tx_t *tx, int type,
                         break;
                 }
 
-                if (tx->tx_nwrq == IBLND_RDMA_FRAGS(conn->ibc_version)) {
-                        CERROR("RDMA too fragmented for %s (%d): "
-                               "%d/%d src %d/%d dst frags\n",
-                               libcfs_nid2str(conn->ibc_peer->ibp_nid),
-                               IBLND_RDMA_FRAGS(conn->ibc_version),
-                               srcidx, srcrd->rd_nfrags,
-                               dstidx, dstrd->rd_nfrags);
-                        rc = -EMSGSIZE;
-                        break;
-                }
+               if (tx->tx_nwrq >= conn->ibc_max_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),
+                              conn->ibc_max_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)), resid);
@@ -1146,15 +1104,20 @@ kiblnd_init_rdma(kib_conn_t *conn, kib_tx_t *tx, int type,
 
                 wrq = &tx->tx_wrq[tx->tx_nwrq];
 
-                wrq->next       = wrq + 1;
-                wrq->wr_id      = kiblnd_ptr2wreqid(tx, IBLND_WID_RDMA);
-                wrq->sg_list    = sge;
-                wrq->num_sge    = 1;
-                wrq->opcode     = IB_WR_RDMA_WRITE;
-                wrq->send_flags = 0;
-
-                wrq->wr.rdma.remote_addr = kiblnd_rd_frag_addr(dstrd, dstidx);
-                wrq->wr.rdma.rkey        = kiblnd_rd_frag_key(dstrd, dstidx);
+               wrq->wr.next            = &(wrq + 1)->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;
+
+#ifdef HAVE_IB_RDMA_WR
+               wrq->remote_addr        = kiblnd_rd_frag_addr(dstrd, dstidx);
+               wrq->rkey               = kiblnd_rd_frag_key(dstrd, dstidx);
+#else
+               wrq->wr.wr.rdma.remote_addr = kiblnd_rd_frag_addr(dstrd, dstidx);
+               wrq->wr.wr.rdma.rkey    = kiblnd_rd_frag_key(dstrd, dstidx);
+#endif
 
                 srcidx = kiblnd_rd_consume_frag(srcrd, srcidx, wrknob);
                 dstidx = kiblnd_rd_consume_frag(dstrd, dstidx, wrknob);
@@ -1187,7 +1150,9 @@ kiblnd_queue_tx_locked(kib_tx_t *tx, kib_conn_t *conn)
        LASSERT(conn->ibc_state >= IBLND_CONN_ESTABLISHED);
 
        tx->tx_queued = 1;
-       tx->tx_deadline = jiffies + (*kiblnd_tunables.kib_timeout * HZ);
+       tx->tx_deadline = jiffies +
+                         msecs_to_jiffies(*kiblnd_tunables.kib_timeout *
+                                          MSEC_PER_SEC);
 
         if (tx->tx_conn == NULL) {
                 kiblnd_conn_addref(conn);
@@ -1235,9 +1200,8 @@ kiblnd_queue_tx (kib_tx_t *tx, kib_conn_t *conn)
 {
        spin_lock(&conn->ibc_lock);
        kiblnd_queue_tx_locked(tx, conn);
+       kiblnd_check_sends_locked(conn);
        spin_unlock(&conn->ibc_lock);
-
-       kiblnd_check_sends(conn);
 }
 
 static int kiblnd_resolve_addr(struct rdma_cm_id *cmid,
@@ -1248,14 +1212,12 @@ static int kiblnd_resolve_addr(struct rdma_cm_id *cmid,
         unsigned short port;
         int rc;
 
-#ifdef HAVE_OFED_RDMA_SET_REUSEADDR
         /* allow the port to be reused */
         rc = rdma_set_reuseaddr(cmid, 1);
         if (rc != 0) {
                 CERROR("Unable to set reuse on cmid: %d\n", rc);
                 return rc;
         }
-#endif
 
         /* look for a free privileged port */
         for (port = PROT_SOCK-1; port > 0; port--) {
@@ -1276,9 +1238,6 @@ static int kiblnd_resolve_addr(struct rdma_cm_id *cmid,
         }
 
         CERROR("Failed to bind to a free privileged port\n");
-#ifndef HAVE_OFED_RDMA_SET_REUSEADDR
-        CERROR("You may need IB verbs that supports rdma_set_reuseaddr()\n");
-#endif
         return rc;
 }
 
@@ -1294,6 +1253,7 @@ kiblnd_connect_peer (kib_peer_t *peer)
 
         LASSERT (net != NULL);
         LASSERT (peer->ibp_connecting > 0);
+       LASSERT(!peer->ibp_reconnecting);
 
         cmid = kiblnd_rdma_create_id(kiblnd_cm_callback, peer, RDMA_PS_TCP,
                                      IB_QPT_RC);
@@ -1334,17 +1294,69 @@ kiblnd_connect_peer (kib_peer_t *peer)
         }
 
         LASSERT (cmid->device != NULL);
-        CDEBUG(D_NET, "%s: connection bound to %s:%u.%u.%u.%u:%s\n",
+       CDEBUG(D_NET, "%s: connection bound to %s:%pI4h:%s\n",
                libcfs_nid2str(peer->ibp_nid), dev->ibd_ifname,
-               HIPQUAD(dev->ibd_ifip), cmid->device->name);
+              &dev->ibd_ifip, cmid->device->name);
 
-        return;
+       return;
 
  failed2:
-        kiblnd_peer_decref(peer);               /* cmid's ref */
-        rdma_destroy_id(cmid);
+       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);
+       kiblnd_peer_connect_failed(peer, 1, rc);
+}
+
+bool
+kiblnd_reconnect_peer(kib_peer_t *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 == 0) {
+               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
@@ -1367,7 +1379,7 @@ kiblnd_launch_tx (lnet_ni_t *ni, kib_tx_t *tx, lnet_nid_t nid)
          * connected */
        read_lock_irqsave(g_lock, flags);
 
-        peer = kiblnd_find_peer_locked(nid);
+        peer = kiblnd_find_peer_locked(ni, nid);
        if (peer != NULL && !list_empty(&peer->ibp_conns)) {
                 /* Found a peer with an established connection */
                 conn = kiblnd_get_conn_locked(peer);
@@ -1385,12 +1397,11 @@ kiblnd_launch_tx (lnet_ni_t *ni, kib_tx_t *tx, lnet_nid_t nid)
        /* Re-try with a write lock */
        write_lock(g_lock);
 
-        peer = kiblnd_find_peer_locked(nid);
+        peer = kiblnd_find_peer_locked(ni, nid);
         if (peer != NULL) {
                if (list_empty(&peer->ibp_conns)) {
                         /* found a peer, but it's still connecting... */
-                        LASSERT (peer->ibp_connecting != 0 ||
-                                 peer->ibp_accepting != 0);
+                       LASSERT(kiblnd_peer_connecting(peer));
                         if (tx != NULL)
                                list_add_tail(&tx->tx_list,
                                                   &peer->ibp_tx_queue);
@@ -1410,26 +1421,25 @@ kiblnd_launch_tx (lnet_ni_t *ni, kib_tx_t *tx, lnet_nid_t nid)
 
        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 != 0) {
-                CERROR("Can't create peer %s\n", libcfs_nid2str(nid));
-                if (tx != NULL) {
-                        tx->tx_status = -EHOSTUNREACH;
-                        tx->tx_waiting = 0;
-                        kiblnd_tx_done(ni, tx);
-                }
-                return;
-        }
+       /* Allocate a peer ready to add to the peer table and retry */
+       rc = kiblnd_create_peer(ni, &peer, nid);
+       if (rc != 0) {
+               CERROR("Can't create peer %s\n", libcfs_nid2str(nid));
+               if (tx != NULL) {
+                       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);
+        peer2 = kiblnd_find_peer_locked(ni, nid);
         if (peer2 != NULL) {
                if (list_empty(&peer2->ibp_conns)) {
                         /* found a peer, but it's still connecting... */
-                        LASSERT (peer2->ibp_connecting != 0 ||
-                                 peer2->ibp_accepting != 0);
+                       LASSERT(kiblnd_peer_connecting(peer2));
                         if (tx != NULL)
                                list_add_tail(&tx->tx_list,
                                                   &peer2->ibp_tx_queue);
@@ -1472,19 +1482,20 @@ 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 iovec     *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;
-        kib_msg_t        *ibmsg;
-        kib_tx_t         *tx;
-        int               nob;
-        int               rc;
+       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;
+       kib_msg_t        *ibmsg;
+       kib_rdma_desc_t  *rd;
+       kib_tx_t         *tx;
+       int               nob;
+       int               rc;
 
         /* NB 'private' is different depending on what we're sending.... */
 
@@ -1524,30 +1535,28 @@ kiblnd_send (lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg)
                        return -ENOMEM;
                }
 
-                ibmsg = tx->tx_msg;
-
-                if ((lntmsg->msg_md->md_options & LNET_MD_KIOV) == 0)
-                        rc = kiblnd_setup_rd_iov(ni, tx,
-                                                 &ibmsg->ibm_u.get.ibgm_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,
-                                                  &ibmsg->ibm_u.get.ibgm_rd,
-                                                  lntmsg->msg_md->md_niov,
-                                                  lntmsg->msg_md->md_iov.kiov,
-                                                  0, lntmsg->msg_md->md_length);
-                if (rc != 0) {
-                        CERROR("Can't setup GET sink for %s: %d\n",
-                               libcfs_nid2str(target.nid), rc);
-                        kiblnd_tx_done(ni, tx);
-                        return -EIO;
-                }
+               ibmsg = tx->tx_msg;
+               rd = &ibmsg->ibm_u.get.ibgm_rd;
+               if ((lntmsg->msg_md->md_options & LNET_MD_KIOV) == 0)
+                       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 != 0) {
+                       CERROR("Can't setup GET sink for %s: %d\n",
+                              libcfs_nid2str(target.nid), rc);
+                       kiblnd_tx_done(ni, tx);
+                       return -EIO;
+               }
 
-                nob = offsetof(kib_get_msg_t, ibgm_rd.rd_frags[tx->tx_nfrags]);
-                ibmsg->ibm_u.get.ibgm_cookie = tx->tx_cookie;
-                ibmsg->ibm_u.get.ibgm_hdr = *hdr;
+               nob = offsetof(kib_get_msg_t, 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);
 
@@ -1644,7 +1653,7 @@ kiblnd_reply (lnet_ni_t *ni, kib_rx_t *rx, lnet_msg_t *lntmsg)
 {
         lnet_process_id_t target = lntmsg->msg_target;
         unsigned int      niov = lntmsg->msg_niov;
-        struct iovec     *iov = lntmsg->msg_iov;
+       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;
@@ -1702,15 +1711,14 @@ kiblnd_reply (lnet_ni_t *ni, kib_rx_t *rx, lnet_msg_t *lntmsg)
 }
 
 int
-kiblnd_recv (lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
-             unsigned int niov, struct iovec *iov, lnet_kiov_t *kiov,
-             unsigned int offset, unsigned int mlen, unsigned int rlen)
+kiblnd_recv(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
+           unsigned int niov, struct kvec *iov, lnet_kiov_t *kiov,
+           unsigned int offset, unsigned int mlen, unsigned int rlen)
 {
         kib_rx_t    *rx = private;
         kib_msg_t   *rxmsg = rx->rx_msg;
         kib_conn_t  *conn = rx->rx_conn;
         kib_tx_t    *tx;
-        kib_msg_t   *txmsg;
        int          nob;
        int          post_credit = IBLND_POSTRX_PEER_CREDIT;
        int          rc = 0;
@@ -1747,7 +1755,10 @@ kiblnd_recv (lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
                 lnet_finalize (ni, lntmsg, 0);
                 break;
 
-        case IBLND_MSG_PUT_REQ:
+       case IBLND_MSG_PUT_REQ: {
+               kib_msg_t       *txmsg;
+               kib_rdma_desc_t *rd;
+
                 if (mlen == 0) {
                         lnet_finalize(ni, lntmsg, 0);
                         kiblnd_send_completion(rx->rx_conn, IBLND_MSG_PUT_NAK, 0,
@@ -1764,28 +1775,27 @@ kiblnd_recv (lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
                         break;
                 }
 
-                txmsg = tx->tx_msg;
-                if (kiov == NULL)
-                        rc = kiblnd_setup_rd_iov(ni, tx,
-                                                 &txmsg->ibm_u.putack.ibpam_rd,
-                                                 niov, iov, offset, mlen);
-                else
-                        rc = kiblnd_setup_rd_kiov(ni, tx,
-                                                  &txmsg->ibm_u.putack.ibpam_rd,
-                                                  niov, kiov, offset, mlen);
-                if (rc != 0) {
-                        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;
-                }
+               txmsg = tx->tx_msg;
+               rd = &txmsg->ibm_u.putack.ibpam_rd;
+               if (kiov == NULL)
+                       rc = kiblnd_setup_rd_iov(ni, tx, rd,
+                                                niov, iov, offset, mlen);
+               else
+                       rc = kiblnd_setup_rd_kiov(ni, tx, rd,
+                                                 niov, kiov, offset, mlen);
+               if (rc != 0) {
+                       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(kib_putack_msg_t, ibpam_rd.rd_frags[tx->tx_nfrags]);
-                txmsg->ibm_u.putack.ibpam_src_cookie = rxmsg->ibm_u.putreq.ibprm_cookie;
-                txmsg->ibm_u.putack.ibpam_dst_cookie = tx->tx_cookie;
+               nob = offsetof(kib_putack_msg_t, 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);
 
@@ -1796,6 +1806,7 @@ kiblnd_recv (lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg, int delayed,
                 /* reposted buffer reserved for PUT_DONE */
                 post_credit = IBLND_POSTRX_NO_CREDIT;
                 break;
+               }
 
         case IBLND_MSG_GET_REQ:
                 if (lntmsg != NULL) {
@@ -1849,10 +1860,7 @@ kiblnd_peer_notify (kib_peer_t *peer)
 
        read_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
 
-       if (list_empty(&peer->ibp_conns) &&
-            peer->ibp_accepting == 0 &&
-            peer->ibp_connecting == 0 &&
-            peer->ibp_error != 0) {
+       if (kiblnd_peer_idle(peer) && peer->ibp_error != 0) {
                 error = peer->ibp_error;
                 peer->ibp_error = 0;
 
@@ -2051,14 +2059,14 @@ kiblnd_peer_connect_failed(kib_peer_t *peer, int active, int error)
                peer->ibp_accepting--;
        }
 
-       if (peer->ibp_connecting != 0 ||
-           peer->ibp_accepting != 0) {
+       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);
@@ -2128,6 +2136,7 @@ kiblnd_connreq_done(kib_conn_t *conn, int status)
         * 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
@@ -2163,6 +2172,12 @@ kiblnd_connreq_done(kib_conn_t *conn, int status)
                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 */
@@ -2173,12 +2188,12 @@ kiblnd_connreq_done(kib_conn_t *conn, int status)
 
                kiblnd_queue_tx_locked(tx, conn);
        }
+       kiblnd_check_sends_locked(conn);
        spin_unlock(&conn->ibc_lock);
 
-       kiblnd_check_sends(conn);
-
        /* schedule blocked rxs */
        kiblnd_handle_early_rxs(conn);
+       kiblnd_conn_decref(conn);
 }
 
 static void
@@ -2193,7 +2208,7 @@ kiblnd_reject(struct rdma_cm_id *cmid, kib_rej_t *rej)
 }
 
 static int
-kiblnd_passive_connect (struct rdma_cm_id *cmid, void *priv, int priv_nob)
+kiblnd_passive_connect(struct rdma_cm_id *cmid, void *priv, int priv_nob)
 {
        rwlock_t                *g_lock = &kiblnd_data.kib_global_lock;
         kib_msg_t             *reqmsg = priv;
@@ -2225,105 +2240,120 @@ kiblnd_passive_connect (struct rdma_cm_id *cmid, void *priv, int priv_nob)
         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 (%u.%u.%u.%u:%hu) is not privileged\n",
-                       HIPQUAD(ip), ntohs(peer_addr->sin_port));
-                goto failed;
-        }
-
-        if (priv_nob < offsetof(kib_msg_t, 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;
+               __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;
+       }
 
-        rc = kiblnd_unpack_msg(reqmsg, priv_nob);
-        if (rc != 0) {
-                CERROR("Can't parse connection request: %d\n", rc);
-                goto failed;
-        }
+       if (priv_nob < offsetof(kib_msg_t, ibm_type)) {
+               CERROR("Short connection request\n");
+               goto failed;
+       }
 
-        nid = reqmsg->ibm_srcnid;
-        ni  = lnet_net2ni(LNET_NIDNET(reqmsg->ibm_dstnid));
+       /* 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 != 0) {
+               CERROR("Can't parse connection request: %d\n", rc);
+               goto failed;
+       }
 
-        if (ni != NULL) {
-                net = (kib_net_t *)ni->ni_data;
-                rej.ibr_incarnation = net->ibn_incarnation;
-        }
+       nid = reqmsg->ibm_srcnid;
+       ni  = lnet_nid2ni_addref(reqmsg->ibm_dstnid);
 
-        if (ni == NULL ||                         /* no matching net */
-            ni->ni_nid != reqmsg->ibm_dstnid ||   /* right NET, wrong NID! */
-            net->ibn_dev != ibdev) {              /* wrong device */
-                CERROR("Can't accept %s on %s (%s:%d:%u.%u.%u.%u): "
-                       "bad dst nid %s\n", libcfs_nid2str(nid),
-                       ni == NULL ? "NA" : libcfs_nid2str(ni->ni_nid),
-                       ibdev->ibd_ifname, ibdev->ibd_nnets,
-                       HIPQUAD(ibdev->ibd_ifip),
-                       libcfs_nid2str(reqmsg->ibm_dstnid));
+       if (ni != NULL) {
+               net = (kib_net_t *)ni->ni_data;
+               rej.ibr_incarnation = net->ibn_incarnation;
+       }
 
-                goto failed;
-        }
+       if (ni == NULL ||                         /* 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 == NULL ? "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 != 0 &&
-            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 !=
-            IBLND_MSG_QUEUE_SIZE(version)) {
-                CERROR("Can't accept %s: incompatible queue depth %d (%d wanted)\n",
-                       libcfs_nid2str(nid), reqmsg->ibm_u.connparams.ibcp_queue_depth,
-                       IBLND_MSG_QUEUE_SIZE(version));
+       if (reqmsg->ibm_dststamp != 0 &&
+           reqmsg->ibm_dststamp != net->ibn_incarnation) {
+               CWARN("Stale connection request\n");
+               rej.ibr_why = IBLND_REJECT_CONN_STALE;
+               goto failed;
+       }
 
-                if (version == IBLND_MSG_VERSION)
-                        rej.ibr_why = IBLND_REJECT_MSG_QUEUE_SIZE;
+       /* I can accept peer's version */
+       version = reqmsg->ibm_version;
 
-                goto failed;
-        }
+       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_max_frags !=
-            IBLND_RDMA_FRAGS(version)) {
-                CERROR("Can't accept %s(version %x): "
-                       "incompatible max_frags %d (%d wanted)\n",
-                       libcfs_nid2str(nid), version,
-                       reqmsg->ibm_u.connparams.ibcp_max_frags,
-                       IBLND_RDMA_FRAGS(version));
+       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_RDMA_FRAGS;
+               if (version == IBLND_MSG_VERSION)
+                       rej.ibr_why = IBLND_REJECT_MSG_QUEUE_SIZE;
 
-                goto failed;
+               goto failed;
+       }
 
-        }
+       if (reqmsg->ibm_u.connparams.ibcp_max_frags >
+           kiblnd_rdma_frags(version, ni)) {
+               CWARN("Can't accept conn from %s (version %x): "
+                     "max_frags %d too large (%d wanted)\n",
+                     libcfs_nid2str(nid), version,
+                     reqmsg->ibm_u.connparams.ibcp_max_frags,
+                     kiblnd_rdma_frags(version, ni));
+
+               if (version >= IBLND_MSG_VERSION)
+                       rej.ibr_why = IBLND_REJECT_RDMA_FRAGS;
+
+               goto failed;
+       } else if (reqmsg->ibm_u.connparams.ibcp_max_frags <
+                  kiblnd_rdma_frags(version, ni) &&
+                  net->ibn_fmr_ps == NULL) {
+               CWARN("Can't accept conn from %s (version %x): "
+                     "max_frags %d incompatible without FMR pool "
+                     "(%d wanted)\n",
+                     libcfs_nid2str(nid), version,
+                     reqmsg->ibm_u.connparams.ibcp_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",
@@ -2333,17 +2363,21 @@ kiblnd_passive_connect (struct rdma_cm_id *cmid, void *priv, int priv_nob)
                 goto failed;
         }
 
-        /* assume 'nid' is a new peer; create  */
-        rc = kiblnd_create_peer(ni, &peer, nid);
-        if (rc != 0) {
-                CERROR("Can't create peer for %s\n", libcfs_nid2str(nid));
-                rej.ibr_why = IBLND_REJECT_NO_RESOURCES;
-                goto failed;
-        }
+       /* assume 'nid' is a new peer; create  */
+       rc = kiblnd_create_peer(ni, &peer, nid);
+       if (rc != 0) {
+               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 = reqmsg->ibm_u.connparams.ibcp_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);
+        peer2 = kiblnd_find_peer_locked(ni, nid);
         if (peer2 != NULL) {
                 if (peer2->ibp_version == 0) {
                         peer2->ibp_version     = version;
@@ -2353,31 +2387,61 @@ kiblnd_passive_connect (struct rdma_cm_id *cmid, void *priv, int priv_nob)
                 /* 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);
+                       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 [old ver: %x, new ver: %x]\n",
-                              libcfs_nid2str(nid), peer2->ibp_version, version);
+                       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;
-                }
+                       kiblnd_peer_decref(peer);
+                       rej.ibr_why = IBLND_REJECT_CONN_STALE;
+                       goto failed;
+               }
 
-                /* tie-break connection race in favour of the higher NID */
-                if (peer2->ibp_connecting != 0 &&
-                    nid < ni->ni_nid) {
+               /* 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 != 0 &&
+                   nid < ni->ni_nid && peer2->ibp_races <
+                   MAX_CONN_RACES_BEFORE_ABORT) {
+                       peer2->ibp_races++;
                        write_unlock_irqrestore(g_lock, flags);
 
-                        CWARN("Conn race %s\n", libcfs_nid2str(peer2->ibp_nid));
-
-                        kiblnd_peer_decref(peer);
-                        rej.ibr_why = IBLND_REJECT_CONN_RACE;
-                        goto failed;
-                }
+                       CDEBUG(D_NET, "Conn race %s\n",
+                              libcfs_nid2str(peer2->ibp_nid));
 
-                peer2->ibp_accepting++;
-                kiblnd_peer_addref(peer2);
+                       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);
@@ -2401,7 +2465,7 @@ kiblnd_passive_connect (struct rdma_cm_id *cmid, void *priv, int priv_nob)
                write_unlock_irqrestore(g_lock, flags);
         }
 
-        conn = kiblnd_create_conn(peer, cmid, IBLND_CONN_PASSIVE_WAIT, version);
+       conn = kiblnd_create_conn(peer, cmid, IBLND_CONN_PASSIVE_WAIT, version);
         if (conn == NULL) {
                 kiblnd_peer_connect_failed(peer, 0, -ENOMEM);
                 kiblnd_peer_decref(peer);
@@ -2411,21 +2475,20 @@ kiblnd_passive_connect (struct rdma_cm_id *cmid, void *priv, int priv_nob)
 
         /* 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          = IBLND_MSG_QUEUE_SIZE(version);
-        conn->ibc_reserved_credits = IBLND_MSG_QUEUE_SIZE(version);
-        LASSERT (conn->ibc_credits + conn->ibc_reserved_credits + IBLND_OOB_MSGS(version)
-                 <= IBLND_RX_MSGS(version));
+       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  = IBLND_MSG_QUEUE_SIZE(version);
-        ackmsg->ibm_u.connparams.ibcp_max_msg_size = IBLND_MSG_SIZE;
-        ackmsg->ibm_u.connparams.ibcp_max_frags    = IBLND_RDMA_FRAGS(version);
+       ackmsg->ibm_u.connparams.ibcp_queue_depth  = conn->ibc_queue_depth;
+       ackmsg->ibm_u.connparams.ibcp_max_frags    = conn->ibc_max_frags;
+       ackmsg->ibm_u.connparams.ibcp_max_msg_size = IBLND_MSG_SIZE;
 
         kiblnd_pack_msg(ni, ackmsg, version, 0, nid, reqmsg->ibm_srcstamp);
 
@@ -2455,57 +2518,97 @@ kiblnd_passive_connect (struct rdma_cm_id *cmid, void *priv, int priv_nob)
         return 0;
 
  failed:
-        if (ni != NULL)
-                lnet_ni_decref(ni);
+       if (ni != NULL) {
+               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;
-        rej.ibr_cp.ibcp_queue_depth = IBLND_MSG_QUEUE_SIZE(version);
-        rej.ibr_cp.ibcp_max_frags   = IBLND_RDMA_FRAGS(version);
-        kiblnd_reject(cmid, &rej);
+       rej.ibr_version = version;
+       kiblnd_reject(cmid, &rej);
 
-        return -ECONNREFUSED;
+       return -ECONNREFUSED;
 }
 
 static void
-kiblnd_reconnect (kib_conn_t *conn, int version,
-                  __u64 incarnation, int why, kib_connparams_t *cp)
+kiblnd_check_reconnect(kib_conn_t *conn, int version,
+                      __u64 incarnation, int why, kib_connparams_t *cp)
 {
-        kib_peer_t    *peer = conn->ibc_peer;
-        char          *reason;
-        int            retry = 0;
-        unsigned long  flags;
+       rwlock_t        *glock = &kiblnd_data.kib_global_lock;
+       kib_peer_t      *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(conn->ibc_state == IBLND_CONN_ACTIVE_CONNECT);
+       LASSERT(peer->ibp_connecting > 0);      /* 'conn' at least */
+       LASSERT(!peer->ibp_reconnecting);
 
-       write_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
+       if (cp) {
+               msg_size        = cp->ibcp_max_msg_size;
+               frag_num        = cp->ibcp_max_frags;
+               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() */
-       if ((!list_empty(&peer->ibp_tx_queue) ||
-             peer->ibp_version != version) &&
-            peer->ibp_connecting == 1 &&
-            peer->ibp_accepting == 0) {
-                retry = 1;
-                peer->ibp_connecting++;
-
-                peer->ibp_version     = version;
-                peer->ibp_incarnation = incarnation;
-        }
-
-       write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
-
-        if (!retry)
-                return;
+       reconnect = (!list_empty(&peer->ibp_tx_queue) ||
+                    peer->ibp_version != version) &&
+                   peer->ibp_connecting == 1 &&
+                   peer->ibp_accepting == 0;
+       if (!reconnect) {
+               reason = "no need";
+               goto out;
+       }
 
         switch (why) {
         default:
                 reason = "Unknown";
                 break;
 
+       case IBLND_REJECT_RDMA_FRAGS: {
+               struct lnet_ioctl_config_o2iblnd_tunables *tunables;
+
+               if (!cp) {
+                       reason = "can't negotiate max frags";
+                       goto out;
+               }
+               tunables = &peer->ibp_ni->ni_lnd_tunables.lnd_tun_u.lnd_o2ib;
+               if (!tunables->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;
@@ -2519,15 +2622,24 @@ kiblnd_reconnect (kib_conn_t *conn, int version,
                 break;
         }
 
-        CNETERR("%s: retrying (%s), %x, %x, "
-                "queue_dep: %d, max_frag: %d, msg_size: %d\n",
-                libcfs_nid2str(peer->ibp_nid),
-                reason, IBLND_MSG_VERSION, version,
-                cp != NULL? cp->ibcp_queue_depth :IBLND_MSG_QUEUE_SIZE(version),
-                cp != NULL? cp->ibcp_max_frags   : IBLND_RDMA_FRAGS(version),
-                cp != NULL? cp->ibcp_max_msg_size: IBLND_MSG_SIZE);
+       conn->ibc_reconnect = 1;
+       peer->ibp_reconnecting = 1;
+       peer->ibp_version = version;
+       if (incarnation != 0)
+               peer->ibp_incarnation = incarnation;
+ out:
+       write_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
 
-        kiblnd_connect_peer(peer);
+       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
@@ -2540,8 +2652,8 @@ kiblnd_rejected (kib_conn_t *conn, int reason, void *priv, int priv_nob)
 
        switch (reason) {
        case IB_CM_REJ_STALE_CONN:
-               kiblnd_reconnect(conn, IBLND_MSG_VERSION, 0,
-                                IBLND_REJECT_CONN_STALE, NULL);
+               kiblnd_check_reconnect(conn, IBLND_MSG_VERSION, 0,
+                                      IBLND_REJECT_CONN_STALE, NULL);
                break;
 
         case IB_CM_REJ_INVALID_SERVICE_ID:
@@ -2621,24 +2733,10 @@ kiblnd_rejected (kib_conn_t *conn, int reason, void *priv, int priv_nob)
                         case IBLND_REJECT_CONN_RACE:
                         case IBLND_REJECT_CONN_STALE:
                         case IBLND_REJECT_CONN_UNCOMPAT:
-                                kiblnd_reconnect(conn, rej->ibr_version,
-                                                 incarnation, rej->ibr_why, cp);
-                                break;
-
-                        case IBLND_REJECT_MSG_QUEUE_SIZE:
-                                CERROR("%s rejected: incompatible message queue depth %d, %d\n",
-                                      libcfs_nid2str(peer->ibp_nid),
-                                      cp != NULL ? cp->ibcp_queue_depth :
-                                      IBLND_MSG_QUEUE_SIZE(rej->ibr_version),
-                                      IBLND_MSG_QUEUE_SIZE(conn->ibc_version));
-                                break;
-
-                        case IBLND_REJECT_RDMA_FRAGS:
-                                CERROR("%s rejected: incompatible # of RDMA fragments %d, %d\n",
-                                      libcfs_nid2str(peer->ibp_nid),
-                                      cp != NULL ? cp->ibcp_max_frags :
-                                      IBLND_RDMA_FRAGS(rej->ibr_version),
-                                      IBLND_RDMA_FRAGS(conn->ibc_version));
+                       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:
@@ -2703,25 +2801,25 @@ kiblnd_check_connreply (kib_conn_t *conn, void *priv, int priv_nob)
                 goto failed;
         }
 
-        if (msg->ibm_u.connparams.ibcp_queue_depth !=
-            IBLND_MSG_QUEUE_SIZE(ver)) {
-                CERROR("%s has incompatible queue depth %d(%d wanted)\n",
-                       libcfs_nid2str(peer->ibp_nid),
-                       msg->ibm_u.connparams.ibcp_queue_depth,
-                       IBLND_MSG_QUEUE_SIZE(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_RDMA_FRAGS(ver)) {
-                CERROR("%s has incompatible max_frags %d (%d wanted)\n",
-                       libcfs_nid2str(peer->ibp_nid),
-                       msg->ibm_u.connparams.ibcp_max_frags,
-                       IBLND_RDMA_FRAGS(ver));
-                rc = -EPROTO;
-                goto failed;
-        }
+       if (msg->ibm_u.connparams.ibcp_max_frags >
+           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,
+                      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",
@@ -2748,11 +2846,13 @@ kiblnd_check_connreply (kib_conn_t *conn, void *priv, int priv_nob)
                 goto failed;
         }
 
-        conn->ibc_incarnation      = msg->ibm_srcstamp;
-        conn->ibc_credits          =
-        conn->ibc_reserved_credits = IBLND_MSG_QUEUE_SIZE(ver);
-        LASSERT (conn->ibc_credits + conn->ibc_reserved_credits + IBLND_OOB_MSGS(ver)
-                 <= IBLND_RX_MSGS(ver));
+       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;
+       LASSERT(conn->ibc_credits + conn->ibc_reserved_credits +
+               IBLND_OOB_MSGS(ver) <= IBLND_RX_MSGS(conn));
 
         kiblnd_connreq_done(conn, 0);
         return;
@@ -2788,7 +2888,8 @@ kiblnd_active_connect (struct rdma_cm_id *cmid)
 
        read_unlock_irqrestore(&kiblnd_data.kib_global_lock, flags);
 
-        conn = kiblnd_create_conn(peer, cmid, IBLND_CONN_ACTIVE_CONNECT, version);
+       conn = kiblnd_create_conn(peer, cmid, IBLND_CONN_ACTIVE_CONNECT,
+                                 version);
         if (conn == NULL) {
                 kiblnd_peer_connect_failed(peer, 1, -ENOMEM);
                 kiblnd_peer_decref(peer); /* lose cmid's ref */
@@ -2801,11 +2902,11 @@ kiblnd_active_connect (struct rdma_cm_id *cmid)
 
         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  = IBLND_MSG_QUEUE_SIZE(version);
-        msg->ibm_u.connparams.ibcp_max_frags    = IBLND_RDMA_FRAGS(version);
-        msg->ibm_u.connparams.ibcp_max_msg_size = IBLND_MSG_SIZE;
+       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;
+       msg->ibm_u.connparams.ibcp_max_msg_size = IBLND_MSG_SIZE;
 
         kiblnd_pack_msg(peer->ibp_ni, msg, version,
                         0, peer->ibp_nid, incarnation);
@@ -2972,11 +3073,10 @@ kiblnd_cm_callback(struct rdma_cm_id *cmid, struct rdma_cm_event *event)
                 /* net keeps its ref on conn! */
                 return 0;
 
-#ifdef HAVE_OFED_RDMA_CMEV_TIMEWAIT_EXIT
         case RDMA_CM_EVENT_TIMEWAIT_EXIT:
                 CDEBUG(D_NET, "Ignore TIMEWAIT_EXIT event\n");
                 return 0;
-#endif
+
        case RDMA_CM_EVENT_DISCONNECTED:
                 conn = (kib_conn_t *)cmid->context;
                 if (conn->ibc_state < IBLND_CONN_ESTABLISHED) {
@@ -2998,11 +3098,9 @@ kiblnd_cm_callback(struct rdma_cm_id *cmid, struct rdma_cm_event *event)
                  * to ignore this */
                 return 0;
 
-#ifdef HAVE_OFED_RDMA_CMEV_ADDRCHANGE
         case RDMA_CM_EVENT_ADDR_CHANGE:
                 LCONSOLE_INFO("Physical link changed (eg hca/port)\n");
                 return 0;
-#endif
         }
 }
 
@@ -3055,9 +3153,9 @@ kiblnd_check_conns (int idx)
        struct list_head *ctmp;
        unsigned long     flags;
 
-        /* NB. We expect to have a look at all the peers and not find any
-         * RDMAs to time out, so we just use a shared lock while we
-         * take a look... */
+       /* NB. We expect to have a look at all the peers and not find any
+        * RDMAs to time out, so we just use a shared lock while we
+        * take a look... */
        read_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
 
        list_for_each(ptmp, peers) {
@@ -3120,7 +3218,11 @@ kiblnd_check_conns (int idx)
                conn = list_entry(checksends.next,
                                  kib_conn_t, ibc_connd_list);
                list_del(&conn->ibc_connd_list);
-               kiblnd_check_sends(conn);
+
+               spin_lock(&conn->ibc_lock);
+               kiblnd_check_sends_locked(conn);
+               spin_unlock(&conn->ibc_lock);
+
                kiblnd_conn_decref(conn);
        }
 }
@@ -3138,10 +3240,22 @@ kiblnd_disconnect_conn (kib_conn_t *conn)
        kiblnd_peer_notify(conn->ibc_peer);
 }
 
+/*
+ * High-water for reconnection to the same peer, reconnection attempt should
+ * be delayed after trying more than KIB_RECONN_HIGH_RACE.
+ */
+#define KIB_RECONN_HIGH_RACE   10
+/*
+ * Allow connd to take a break and handle other things after consecutive
+ * reconnection attemps.
+ */
+#define KIB_RECONN_BREAK       100
+
 int
 kiblnd_connd (void *arg)
 {
-       wait_queue_t     wait;
+       spinlock_t        *lock= &kiblnd_data.kib_connd_lock;
+       wait_queue_t       wait;
        unsigned long      flags;
        kib_conn_t        *conn;
        int                timeout;
@@ -3150,30 +3264,45 @@ kiblnd_connd (void *arg)
        int                peer_index = 0;
        unsigned long      deadline = jiffies;
 
-       cfs_block_allsigs ();
+       cfs_block_allsigs();
 
-       init_waitqueue_entry_current (&wait);
+       init_waitqueue_entry(&wait, current);
        kiblnd_data.kib_connd = current;
 
-       spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+       spin_lock_irqsave(lock, flags);
 
-        while (!kiblnd_data.kib_shutdown) {
+       while (!kiblnd_data.kib_shutdown) {
+               int reconn = 0;
 
                 dropped_lock = 0;
 
                if (!list_empty(&kiblnd_data.kib_connd_zombies)) {
-                       conn = list_entry(kiblnd_data. \
-                                              kib_connd_zombies.next,
-                                              kib_conn_t, ibc_list);
+                       kib_peer_t *peer = NULL;
+
+                       conn = list_entry(kiblnd_data.kib_connd_zombies.next,
+                                         kib_conn_t, ibc_list);
                        list_del(&conn->ibc_list);
+                       if (conn->ibc_reconnect) {
+                               peer = conn->ibc_peer;
+                               kiblnd_peer_addref(peer);
+                       }
 
-                       spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock,
-                                              flags);
+                       spin_unlock_irqrestore(lock, flags);
                        dropped_lock = 1;
 
-                       kiblnd_destroy_conn(conn);
+                       kiblnd_destroy_conn(conn, !peer);
+
+                       spin_lock_irqsave(lock, flags);
+                       if (!peer)
+                               continue;
 
-                       spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+                       conn->ibc_peer = peer;
+                       if (peer->ibp_reconnected < KIB_RECONN_HIGH_RACE)
+                               list_add_tail(&conn->ibc_list,
+                                             &kiblnd_data.kib_reconn_list);
+                       else
+                               list_add_tail(&conn->ibc_list,
+                                             &kiblnd_data.kib_reconn_wait);
                }
 
                if (!list_empty(&kiblnd_data.kib_connd_conns)) {
@@ -3181,16 +3310,40 @@ kiblnd_connd (void *arg)
                                              kib_conn_t, ibc_list);
                        list_del(&conn->ibc_list);
 
-                       spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock,
-                                              flags);
+                       spin_unlock_irqrestore(lock, flags);
                        dropped_lock = 1;
 
                        kiblnd_disconnect_conn(conn);
                        kiblnd_conn_decref(conn);
 
-                       spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+                       spin_lock_irqsave(lock, flags);
                 }
 
+               while (reconn < KIB_RECONN_BREAK) {
+                       if (kiblnd_data.kib_reconn_sec !=
+                           ktime_get_real_seconds()) {
+                               kiblnd_data.kib_reconn_sec = ktime_get_real_seconds();
+                               list_splice_init(&kiblnd_data.kib_reconn_wait,
+                                                &kiblnd_data.kib_reconn_list);
+                       }
+
+                       if (list_empty(&kiblnd_data.kib_reconn_list))
+                               break;
+
+                       conn = list_entry(kiblnd_data.kib_reconn_list.next,
+                                         kib_conn_t, ibc_list);
+                       list_del(&conn->ibc_list);
+
+                       spin_unlock_irqrestore(lock, flags);
+                       dropped_lock = 1;
+
+                       reconn += kiblnd_reconnect_peer(conn->ibc_peer);
+                       kiblnd_peer_decref(conn->ibc_peer);
+                       LIBCFS_FREE(conn, sizeof(*conn));
+
+                       spin_lock_irqsave(lock, flags);
+               }
+
                 /* careful with the jiffy wrap... */
                 timeout = (int)(deadline - jiffies);
                 if (timeout <= 0) {
@@ -3198,7 +3351,7 @@ kiblnd_connd (void *arg)
                         const int p = 1;
                         int       chunk = kiblnd_data.kib_peer_hash_size;
 
-                       spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);
+                       spin_unlock_irqrestore(lock, flags);
                         dropped_lock = 1;
 
                         /* Time to check for RDMA timeouts on a few more
@@ -3221,8 +3374,8 @@ kiblnd_connd (void *arg)
                                             kiblnd_data.kib_peer_hash_size;
                        }
 
-                       deadline += p * HZ;
-                       spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+                       deadline += msecs_to_jiffies(p * MSEC_PER_SEC);
+                       spin_lock_irqsave(lock, flags);
                }
 
                if (dropped_lock)
@@ -3231,16 +3384,16 @@ kiblnd_connd (void *arg)
                /* Nothing to do for 'timeout'  */
                set_current_state(TASK_INTERRUPTIBLE);
                add_wait_queue(&kiblnd_data.kib_connd_waitq, &wait);
-               spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);
+               spin_unlock_irqrestore(lock, flags);
 
-               waitq_timedwait(&wait, TASK_INTERRUPTIBLE, timeout);
+               schedule_timeout(timeout);
 
                set_current_state(TASK_RUNNING);
                remove_wait_queue(&kiblnd_data.kib_connd_waitq, &wait);
-               spin_lock_irqsave(&kiblnd_data.kib_connd_lock, flags);
+               spin_lock_irqsave(lock, flags);
        }
 
-       spin_unlock_irqrestore(&kiblnd_data.kib_connd_lock, flags);
+       spin_unlock_irqrestore(lock, flags);
 
        kiblnd_thread_fini();
        return 0;
@@ -3255,6 +3408,10 @@ kiblnd_qp_event(struct ib_event *event, void *arg)
         case IB_EVENT_COMM_EST:
                 CDEBUG(D_NET, "%s established\n",
                        libcfs_nid2str(conn->ibc_peer->ibp_nid));
+               /* We received a packet but connection isn't established
+                * probably handshake packet was lost, so free to
+                * force make connection established */
+               rdma_notify(conn->ibc_cmid, IB_EVENT_COMM_EST);
                 return;
 
         default:
@@ -3267,9 +3424,15 @@ kiblnd_qp_event(struct ib_event *event, void *arg)
 static void
 kiblnd_complete (struct ib_wc *wc)
 {
-        switch (kiblnd_wreqid2type(wc->wr_id)) {
-        default:
-                LBUG();
+       switch (kiblnd_wreqid2type(wc->wr_id)) {
+       default:
+               LBUG();
+
+       case IBLND_WID_MR:
+               if (wc->status != IB_WC_SUCCESS &&
+                   wc->status != IB_WC_WR_FLUSH_ERR)
+                       CNETERR("FastReg failed: %d\n", wc->status);
+               return;
 
         case IBLND_WID_RDMA:
                 /* We only get RDMA completion notification if it fails.  All
@@ -3349,16 +3512,16 @@ kiblnd_scheduler(void *arg)
 
        cfs_block_allsigs();
 
-       init_waitqueue_entry_current(&wait);
+       init_waitqueue_entry(&wait, current);
 
        sched = kiblnd_data.kib_scheds[KIB_THREAD_CPT(id)];
 
        rc = cfs_cpt_bind(lnet_cpt_table(), sched->ibs_cpt);
        if (rc != 0) {
-               CWARN("Failed to bind on CPT %d, please verify whether "
-                     "all CPUs are healthy and reload modules if necessary, "
-                     "otherwise your system might under risk of low "
-                     "performance\n", sched->ibs_cpt);
+               CWARN("Unable to bind on CPU partition %d, please verify "
+                     "whether all CPUs are healthy and reload modules if "
+                     "necessary, otherwise your system might under risk of "
+                     "low performance\n", sched->ibs_cpt);
        }
 
        spin_lock_irqsave(&sched->ibs_lock, flags);
@@ -3385,6 +3548,8 @@ kiblnd_scheduler(void *arg)
 
                        spin_unlock_irqrestore(&sched->ibs_lock, flags);
 
+                       wc.wr_id = IBLND_WID_INVAL;
+
                         rc = ib_poll_cq(conn->ibc_cq, 1, &wc);
                         if (rc == 0) {
                                 rc = ib_req_notify_cq(conn->ibc_cq,
@@ -3403,6 +3568,19 @@ kiblnd_scheduler(void *arg)
                                rc = ib_poll_cq(conn->ibc_cq, 1, &wc);
                        }
 
+                       if (unlikely(rc > 0 && wc.wr_id == IBLND_WID_INVAL)) {
+                               LCONSOLE_ERROR(
+                                       "ib_poll_cq (rc: %d) returned invalid "
+                                       "wr_id, opcode %d, status: %d, "
+                                       "vendor_err: %d, conn: %s status: %d\n"
+                                       "please upgrade firmware and OFED or "
+                                       "contact vendor.\n", rc,
+                                       wc.opcode, wc.status, wc.vendor_err,
+                                       libcfs_nid2str(conn->ibc_peer->ibp_nid),
+                                       conn->ibc_state);
+                               rc = -EINVAL;
+                       }
+
                        if (rc < 0) {
                                CWARN("%s: ib_poll_cq failed: %d, "
                                      "closing connection\n",
@@ -3448,7 +3626,7 @@ kiblnd_scheduler(void *arg)
                add_wait_queue_exclusive(&sched->ibs_waitq, &wait);
                spin_unlock_irqrestore(&sched->ibs_lock, flags);
 
-               waitq_wait(&wait, TASK_INTERRUPTIBLE);
+               schedule();
                busy_loops = 0;
 
                remove_wait_queue(&sched->ibs_waitq, &wait);
@@ -3466,16 +3644,16 @@ int
 kiblnd_failover_thread(void *arg)
 {
        rwlock_t                *glock = &kiblnd_data.kib_global_lock;
-       kib_dev_t         *dev;
-       wait_queue_t     wait;
-       unsigned long      flags;
-       int                rc;
+       kib_dev_t               *dev;
+       wait_queue_t            wait;
+       unsigned long           flags;
+       int                     rc;
 
-       LASSERT (*kiblnd_tunables.kib_dev_failover != 0);
+       LASSERT(*kiblnd_tunables.kib_dev_failover != 0);
 
-       cfs_block_allsigs ();
+       cfs_block_allsigs();
 
-       init_waitqueue_entry_current(&wait);
+       init_waitqueue_entry(&wait, current);
        write_lock_irqsave(glock, flags);
 
         while (!kiblnd_data.kib_shutdown) {