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b=21396 Don't hog cpu in connd.
[fs/lustre-release.git] / lnet / klnds / socklnd / socklnd_cb.c
index efec018..669e491 100644 (file)
 #include "socklnd.h"
 
 ksock_tx_t *
-ksocknal_alloc_tx (int size)
+ksocknal_alloc_tx(int type, int size)
 {
         ksock_tx_t *tx = NULL;
 
-        if (size == KSOCK_NOOP_TX_SIZE) {
+        if (type == KSOCK_MSG_NOOP) {
+                LASSERT (size == KSOCK_NOOP_TX_SIZE);
+
                 /* searching for a noop tx in free list */
-                spin_lock(&ksocknal_data.ksnd_tx_lock);
+                cfs_spin_lock(&ksocknal_data.ksnd_tx_lock);
 
-                if (!list_empty(&ksocknal_data.ksnd_idle_noop_txs)) {
-                        tx = list_entry(ksocknal_data.ksnd_idle_noop_txs.next,
-                                        ksock_tx_t, tx_list);
+                if (!cfs_list_empty(&ksocknal_data.ksnd_idle_noop_txs)) {
+                        tx = cfs_list_entry(ksocknal_data.ksnd_idle_noop_txs. \
+                                            next, ksock_tx_t, tx_list);
                         LASSERT(tx->tx_desc_size == size);
-                        list_del(&tx->tx_list);
+                        cfs_list_del(&tx->tx_list);
                 }
 
-                spin_unlock(&ksocknal_data.ksnd_tx_lock);
+                cfs_spin_unlock(&ksocknal_data.ksnd_tx_lock);
         }
 
         if (tx == NULL)
@@ -51,39 +53,59 @@ ksocknal_alloc_tx (int size)
         if (tx == NULL)
                 return NULL;
 
-        atomic_set(&tx->tx_refcount, 1);
-        tx->tx_desc_size = size;
-        atomic_inc(&ksocknal_data.ksnd_nactive_txs);
+        cfs_atomic_set(&tx->tx_refcount, 1);
+        tx->tx_zc_capable = 0;
+        tx->tx_zc_checked = 0;
+        tx->tx_desc_size  = size;
+
+        cfs_atomic_inc(&ksocknal_data.ksnd_nactive_txs);
+
+        return tx;
+}
+
+ksock_tx_t *
+ksocknal_alloc_tx_noop(__u64 cookie, int nonblk)
+{
+        ksock_tx_t *tx;
+
+        tx = ksocknal_alloc_tx(KSOCK_MSG_NOOP, KSOCK_NOOP_TX_SIZE);
+        if (tx == NULL) {
+                CERROR("Can't allocate noop tx desc\n");
+                return NULL;
+        }
+
+        tx->tx_conn     = NULL;
+        tx->tx_lnetmsg  = NULL;
+        tx->tx_kiov     = NULL;
+        tx->tx_nkiov    = 0;
+        tx->tx_iov      = tx->tx_frags.virt.iov;
+        tx->tx_niov     = 1;
+        tx->tx_nonblk   = nonblk;
+
+        socklnd_init_msg(&tx->tx_msg, KSOCK_MSG_NOOP);
+        tx->tx_msg.ksm_zc_cookies[1] = cookie;
 
         return tx;
 }
 
+
 void
 ksocknal_free_tx (ksock_tx_t *tx)
 {
-        atomic_dec(&ksocknal_data.ksnd_nactive_txs);
+        cfs_atomic_dec(&ksocknal_data.ksnd_nactive_txs);
 
-        if (tx->tx_desc_size == KSOCK_NOOP_TX_SIZE) {
+        if (tx->tx_lnetmsg == NULL && tx->tx_desc_size == KSOCK_NOOP_TX_SIZE) {
                 /* it's a noop tx */
-                spin_lock(&ksocknal_data.ksnd_tx_lock);
+                cfs_spin_lock(&ksocknal_data.ksnd_tx_lock);
 
-                list_add(&tx->tx_list, &ksocknal_data.ksnd_idle_noop_txs);
+                cfs_list_add(&tx->tx_list, &ksocknal_data.ksnd_idle_noop_txs);
 
-                spin_unlock(&ksocknal_data.ksnd_tx_lock);
+                cfs_spin_unlock(&ksocknal_data.ksnd_tx_lock);
         } else {
                 LIBCFS_FREE(tx, tx->tx_desc_size);
         }
 }
 
-void
-ksocknal_init_msg(ksock_msg_t *msg, int type)
-{
-        msg->ksm_type           = type;
-        msg->ksm_csum           = 0;
-        msg->ksm_zc_req_cookie  = 0;
-        msg->ksm_zc_ack_cookie  = 0;
-}
-
 int
 ksocknal_send_iov (ksock_conn_t *conn, ksock_tx_t *tx)
 {
@@ -107,8 +129,8 @@ ksocknal_send_iov (ksock_conn_t *conn, ksock_tx_t *tx)
         do {
                 LASSERT (tx->tx_niov > 0);
 
-                if (nob < iov->iov_len) {
-                        iov->iov_base = (void *)(((unsigned long)(iov->iov_base)) + nob);
+                if (nob < (int) iov->iov_len) {
+                        iov->iov_base = (void *)((char *)iov->iov_base + nob);
                         iov->iov_len -= nob;
                         return (rc);
                 }
@@ -145,13 +167,13 @@ ksocknal_send_kiov (ksock_conn_t *conn, ksock_tx_t *tx)
         do {
                 LASSERT(tx->tx_nkiov > 0);
 
-                if (nob < kiov->kiov_len) {
+                if (nob < (int)kiov->kiov_len) {
                         kiov->kiov_offset += nob;
                         kiov->kiov_len -= nob;
                         return rc;
                 }
 
-                nob -= kiov->kiov_len;
+                nob -= (int)kiov->kiov_len;
                 tx->tx_kiov = ++kiov;
                 tx->tx_nkiov--;
         } while (nob != 0);
@@ -188,7 +210,7 @@ ksocknal_transmit (ksock_conn_t *conn, ksock_tx_t *tx)
                         rc = ksocknal_send_kiov (conn, tx);
                 }
 
-                bufnob = SOCK_WMEM_QUEUED(conn->ksnc_sock);
+                bufnob = libcfs_sock_wmem_queued(conn->ksnc_sock);
                 if (rc > 0)                     /* sent something? */
                         conn->ksnc_tx_bufnob += rc; /* account it */
 
@@ -199,42 +221,23 @@ ksocknal_transmit (ksock_conn_t *conn, ksock_tx_t *tx)
                                 cfs_time_shift(*ksocknal_tunables.ksnd_timeout);
                         conn->ksnc_peer->ksnp_last_alive = cfs_time_current();
                         conn->ksnc_tx_bufnob = bufnob;
-                        mb();
+                        cfs_mb();
                 }
 
                 if (rc <= 0) { /* Didn't write anything? */
-                        ksock_sched_t *sched;
 
                         if (rc == 0) /* some stacks return 0 instead of -EAGAIN */
                                 rc = -EAGAIN;
 
-                        if (rc != -EAGAIN)
-                                break;
-
                         /* Check if EAGAIN is due to memory pressure */
-
-                        sched = conn->ksnc_scheduler;
-                        spin_lock_bh (&sched->kss_lock);
-
-                        if (!SOCK_TEST_NOSPACE(conn->ksnc_sock) &&
-                            !conn->ksnc_tx_ready) {
-                                /* SOCK_NOSPACE is set when the socket fills
-                                 * and cleared in the write_space callback
-                                 * (which also sets ksnc_tx_ready).  If
-                                 * SOCK_NOSPACE and ksnc_tx_ready are BOTH
-                                 * zero, I didn't fill the socket and
-                                 * write_space won't reschedule me, so I
-                                 * return -ENOMEM to get my caller to retry
-                                 * after a timeout */
+                        if(rc == -EAGAIN && ksocknal_lib_memory_pressure(conn))
                                 rc = -ENOMEM;
-                        }
 
-                        spin_unlock_bh (&sched->kss_lock);
                         break;
                 }
 
                 /* socket's wmem_queued now includes 'rc' bytes */
-                atomic_sub (rc, &conn->ksnc_tx_nob);
+                cfs_atomic_sub (rc, &conn->ksnc_tx_nob);
                 rc = 0;
 
         } while (tx->tx_resid != 0);
@@ -265,7 +268,7 @@ ksocknal_recv_iov (ksock_conn_t *conn)
         conn->ksnc_peer->ksnp_last_alive = cfs_time_current();
         conn->ksnc_rx_deadline =
                 cfs_time_shift(*ksocknal_tunables.ksnd_timeout);
-        mb();                           /* order with setting rx_started */
+        cfs_mb();                       /* order with setting rx_started */
         conn->ksnc_rx_started = 1;
 
         conn->ksnc_rx_nob_wanted -= nob;
@@ -274,9 +277,9 @@ ksocknal_recv_iov (ksock_conn_t *conn)
         do {
                 LASSERT (conn->ksnc_rx_niov > 0);
 
-                if (nob < iov->iov_len) {
+                if (nob < (int)iov->iov_len) {
                         iov->iov_len -= nob;
-                        iov->iov_base = (void *)(((unsigned long)iov->iov_base) + nob);
+                        iov->iov_base = (void *)((char *)iov->iov_base + nob);
                         return (-EAGAIN);
                 }
 
@@ -309,7 +312,7 @@ ksocknal_recv_kiov (ksock_conn_t *conn)
         conn->ksnc_peer->ksnp_last_alive = cfs_time_current();
         conn->ksnc_rx_deadline =
                 cfs_time_shift(*ksocknal_tunables.ksnd_timeout);
-        mb();                           /* order with setting rx_started */
+        cfs_mb();                       /* order with setting rx_started */
         conn->ksnc_rx_started = 1;
 
         conn->ksnc_rx_nob_wanted -= nob;
@@ -318,7 +321,7 @@ ksocknal_recv_kiov (ksock_conn_t *conn)
         do {
                 LASSERT (conn->ksnc_rx_nkiov > 0);
 
-                if (nob < kiov->kiov_len) {
+                if (nob < (int) kiov->kiov_len) {
                         kiov->kiov_offset += nob;
                         kiov->kiov_len -= nob;
                         return -EAGAIN;
@@ -403,26 +406,26 @@ ksocknal_tx_done (lnet_ni_t *ni, ksock_tx_t *tx)
 }
 
 void
-ksocknal_txlist_done (lnet_ni_t *ni, struct list_head *txlist, int error)
+ksocknal_txlist_done (lnet_ni_t *ni, cfs_list_t *txlist, int error)
 {
         ksock_tx_t *tx;
 
-        while (!list_empty (txlist)) {
-                tx = list_entry (txlist->next, ksock_tx_t, tx_list);
+        while (!cfs_list_empty (txlist)) {
+                tx = cfs_list_entry (txlist->next, ksock_tx_t, tx_list);
 
                 if (error && tx->tx_lnetmsg != NULL) {
                         CDEBUG (D_NETERROR, "Deleting packet type %d len %d %s->%s\n",
                                 le32_to_cpu (tx->tx_lnetmsg->msg_hdr.type),
                                 le32_to_cpu (tx->tx_lnetmsg->msg_hdr.payload_length),
                                 libcfs_nid2str(le64_to_cpu(tx->tx_lnetmsg->msg_hdr.src_nid)),
-                                libcfs_nid2str(le64_to_cpu (tx->tx_lnetmsg->msg_hdr.dest_nid)));
+                                libcfs_nid2str(le64_to_cpu(tx->tx_lnetmsg->msg_hdr.dest_nid)));
                 } else if (error) {
                         CDEBUG (D_NETERROR, "Deleting noop packet\n");
                 }
 
-                list_del (&tx->tx_list);
+                cfs_list_del (&tx->tx_list);
 
-                LASSERT (atomic_read(&tx->tx_refcount) == 1);
+                LASSERT (cfs_atomic_read(&tx->tx_refcount) == 1);
                 ksocknal_tx_done (ni, tx);
         }
 }
@@ -432,65 +435,67 @@ ksocknal_check_zc_req(ksock_tx_t *tx)
 {
         ksock_conn_t   *conn = tx->tx_conn;
         ksock_peer_t   *peer = conn->ksnc_peer;
-        lnet_kiov_t    *kiov = tx->tx_kiov;
-        int             nkiov = tx->tx_nkiov;
 
-        /* Set tx_msg.ksm_zc_req_cookie to a unique non-zero cookie and add tx
+        /* Set tx_msg.ksm_zc_cookies[0] to a unique non-zero cookie and add tx
          * to ksnp_zc_req_list if some fragment of this message should be sent
          * zero-copy.  Our peer will send an ACK containing this cookie when
          * she has received this message to tell us we can signal completion.
-         * tx_msg.ksm_zc_req_cookie remains non-zero while tx is on
+         * tx_msg.ksm_zc_cookies[0] remains non-zero while tx is on
          * ksnp_zc_req_list. */
+        LASSERT (tx->tx_msg.ksm_type != KSOCK_MSG_NOOP);
+        LASSERT (tx->tx_zc_capable);
 
-        if (conn->ksnc_proto != &ksocknal_protocol_v2x ||
-            !conn->ksnc_zc_capable)
-                return;
-
-        while (nkiov > 0) {
-                if (kiov->kiov_len >= *ksocknal_tunables.ksnd_zc_min_frag)
-                        break;
-                --nkiov;
-                ++kiov;
-        }
+        tx->tx_zc_checked = 1;
 
-        if (nkiov == 0)
+        if (conn->ksnc_proto == &ksocknal_protocol_v1x ||
+            !conn->ksnc_zc_capable)
                 return;
 
         /* assign cookie and queue tx to pending list, it will be released when
-         * a matching ack is received. See ksocknal_handle_zc_ack() */
+         * a matching ack is received. See ksocknal_handle_zcack() */
 
         ksocknal_tx_addref(tx);
 
-        spin_lock(&peer->ksnp_lock);
+        cfs_spin_lock(&peer->ksnp_lock);
 
         /* ZC_REQ is going to be pinned to the peer */
         tx->tx_deadline =
                 cfs_time_shift(*ksocknal_tunables.ksnd_timeout);
 
-        LASSERT (tx->tx_msg.ksm_zc_req_cookie == 0);
-        tx->tx_msg.ksm_zc_req_cookie = peer->ksnp_zc_next_cookie++;
-        list_add_tail(&tx->tx_zc_list, &peer->ksnp_zc_req_list);
+        LASSERT (tx->tx_msg.ksm_zc_cookies[0] == 0);
+
+        tx->tx_msg.ksm_zc_cookies[0] = peer->ksnp_zc_next_cookie++;
+
+        if (peer->ksnp_zc_next_cookie == 0)
+                peer->ksnp_zc_next_cookie = SOCKNAL_KEEPALIVE_PING + 1;
 
-        spin_unlock(&peer->ksnp_lock);
+        cfs_list_add_tail(&tx->tx_zc_list, &peer->ksnp_zc_req_list);
+
+        cfs_spin_unlock(&peer->ksnp_lock);
 }
 
 static void
-ksocknal_unzc_req(ksock_tx_t *tx)
+ksocknal_uncheck_zc_req(ksock_tx_t *tx)
 {
         ksock_peer_t   *peer = tx->tx_conn->ksnc_peer;
 
-        spin_lock(&peer->ksnp_lock);
+        LASSERT (tx->tx_msg.ksm_type != KSOCK_MSG_NOOP);
+        LASSERT (tx->tx_zc_capable);
+
+        tx->tx_zc_checked = 0;
+
+        cfs_spin_lock(&peer->ksnp_lock);
 
-        if (tx->tx_msg.ksm_zc_req_cookie == 0) {
+        if (tx->tx_msg.ksm_zc_cookies[0] == 0) {
                 /* Not waiting for an ACK */
-                spin_unlock(&peer->ksnp_lock);
+                cfs_spin_unlock(&peer->ksnp_lock);
                 return;
         }
 
-        tx->tx_msg.ksm_zc_req_cookie = 0;
-        list_del(&tx->tx_zc_list);
+        tx->tx_msg.ksm_zc_cookies[0] = 0;
+        cfs_list_del(&tx->tx_zc_list);
 
-        spin_unlock(&peer->ksnp_lock);
+        cfs_spin_unlock(&peer->ksnp_lock);
 
         ksocknal_tx_decref(tx);
 }
@@ -500,10 +505,8 @@ ksocknal_process_transmit (ksock_conn_t *conn, ksock_tx_t *tx)
 {
         int            rc;
 
-        if (!tx->tx_checked_zc) {
-                tx->tx_checked_zc = 1;
+        if (tx->tx_zc_capable && !tx->tx_zc_checked)
                 ksocknal_check_zc_req(tx);
-        }
 
         rc = ksocknal_transmit (conn, tx);
 
@@ -525,21 +528,21 @@ ksocknal_process_transmit (ksock_conn_t *conn, ksock_tx_t *tx)
                 counter++;   /* exponential backoff warnings */
                 if ((counter & (-counter)) == counter)
                         CWARN("%u ENOMEM tx %p (%u allocated)\n",
-                              counter, conn, atomic_read(&libcfs_kmemory));
+                              counter, conn, cfs_atomic_read(&libcfs_kmemory));
 
                 /* Queue on ksnd_enomem_conns for retry after a timeout */
-                spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
+                cfs_spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
 
                 /* enomem list takes over scheduler's ref... */
                 LASSERT (conn->ksnc_tx_scheduled);
-                list_add_tail(&conn->ksnc_tx_list,
-                              &ksocknal_data.ksnd_enomem_conns);
+                cfs_list_add_tail(&conn->ksnc_tx_list,
+                                  &ksocknal_data.ksnd_enomem_conns);
                 if (!cfs_time_aftereq(cfs_time_add(cfs_time_current(),
                                                    SOCKNAL_ENOMEM_RETRY),
                                    ksocknal_data.ksnd_reaper_waketime))
                         cfs_waitq_signal (&ksocknal_data.ksnd_reaper_waitq);
 
-                spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
+                cfs_spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
                 return (rc);
         }
 
@@ -567,7 +570,8 @@ ksocknal_process_transmit (ksock_conn_t *conn, ksock_tx_t *tx)
                        conn->ksnc_port);
         }
 
-        ksocknal_unzc_req(tx);
+        if (tx->tx_zc_checked)
+                ksocknal_uncheck_zc_req(tx);
 
         /* it's not an error if conn is being closed */
         ksocknal_close_conn_and_siblings (conn,
@@ -589,134 +593,96 @@ ksocknal_launch_connection_locked (ksock_route_t *route)
         route->ksnr_scheduled = 1;              /* scheduling conn for connd */
         ksocknal_route_addref(route);           /* extra ref for connd */
 
-        spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
+        cfs_spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
 
-        list_add_tail (&route->ksnr_connd_list,
-                       &ksocknal_data.ksnd_connd_routes);
+        cfs_list_add_tail (&route->ksnr_connd_list,
+                           &ksocknal_data.ksnd_connd_routes);
         cfs_waitq_signal (&ksocknal_data.ksnd_connd_waitq);
 
-        spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+        cfs_spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+}
+
+void
+ksocknal_launch_all_connections_locked (ksock_peer_t *peer)
+{
+        ksock_route_t *route;
+
+        /* called holding write lock on ksnd_global_lock */
+        for (;;) {
+                /* launch any/all connections that need it */
+                route = ksocknal_find_connectable_route_locked(peer);
+                if (route == NULL)
+                        return;
+
+                ksocknal_launch_connection_locked(route);
+        }
 }
 
 ksock_conn_t *
-ksocknal_find_conn_locked (int payload_nob, ksock_peer_t *peer)
+ksocknal_find_conn_locked(ksock_peer_t *peer, ksock_tx_t *tx, int nonblk)
 {
-        struct list_head *tmp;
+        cfs_list_t       *tmp;
+        ksock_conn_t     *conn;
         ksock_conn_t     *typed = NULL;
-        int               tnob  = 0;
         ksock_conn_t     *fallback = NULL;
+        int               tnob     = 0;
         int               fnob     = 0;
-        ksock_conn_t     *conn;
-
-        list_for_each (tmp, &peer->ksnp_conns) {
-                ksock_conn_t *c = list_entry(tmp, ksock_conn_t, ksnc_list);
-                int           hdr_nob = 0;
-#if SOCKNAL_ROUND_ROBIN
-                const int     nob = 0;
-#else
-                int           nob = atomic_read(&c->ksnc_tx_nob) +
-                                        SOCK_WMEM_QUEUED(c->ksnc_sock);
-#endif
-                LASSERT (!c->ksnc_closing);
-                LASSERT (c->ksnc_proto != NULL);
 
-                if (fallback == NULL || nob < fnob) {
-                        fallback = c;
-                        fnob     = nob;
-                }
+        cfs_list_for_each (tmp, &peer->ksnp_conns) {
+                ksock_conn_t *c  = cfs_list_entry(tmp, ksock_conn_t, ksnc_list);
+                int           nob = cfs_atomic_read(&c->ksnc_tx_nob) +
+                                    libcfs_sock_wmem_queued(c->ksnc_sock);
+                int           rc;
 
-                if (!*ksocknal_tunables.ksnd_typed_conns)
-                        continue;
+                LASSERT (!c->ksnc_closing);
+                LASSERT (c->ksnc_proto != NULL &&
+                         c->ksnc_proto->pro_match_tx != NULL);
 
-                if (payload_nob == 0) {
-                        /* noop packet */
-                        hdr_nob = offsetof(ksock_msg_t, ksm_u);
-                } else {
-                        /* lnet packet */
-                        hdr_nob = (c->ksnc_proto == &ksocknal_protocol_v2x)?
-                                  offsetof(ksock_msg_t, ksm_u.lnetmsg.ksnm_payload):
-                                  sizeof(lnet_hdr_t);
-                }
+                rc = c->ksnc_proto->pro_match_tx(c, tx, nonblk);
 
-                switch (c->ksnc_type) {
+                switch (rc) {
                 default:
-                        CERROR("ksnc_type bad: %u\n", c->ksnc_type);
                         LBUG();
-                case SOCKLND_CONN_ANY:
-                        break;
-                case SOCKLND_CONN_BULK_IN:
+                case SOCKNAL_MATCH_NO: /* protocol rejected the tx */
                         continue;
-                case SOCKLND_CONN_BULK_OUT:
-                        if ((hdr_nob + payload_nob) < *ksocknal_tunables.ksnd_min_bulk)
-                                continue;
-                        break;
-                case SOCKLND_CONN_CONTROL:
-                        if ((hdr_nob + payload_nob) >= *ksocknal_tunables.ksnd_min_bulk)
-                                continue;
+
+                case SOCKNAL_MATCH_YES: /* typed connection */
+                        if (typed == NULL || tnob > nob ||
+                            (tnob == nob && *ksocknal_tunables.ksnd_round_robin &&
+                             cfs_time_after(typed->ksnc_tx_last_post, c->ksnc_tx_last_post))) {
+                                typed = c;
+                                tnob  = nob;
+                        }
                         break;
-                }
 
-                if (typed == NULL || nob < tnob) {
-                        typed = c;
-                        tnob  = nob;
+                case SOCKNAL_MATCH_MAY: /* fallback connection */
+                        if (fallback == NULL || fnob > nob ||
+                            (fnob == nob && *ksocknal_tunables.ksnd_round_robin &&
+                             cfs_time_after(fallback->ksnc_tx_last_post, c->ksnc_tx_last_post))) {
+                                fallback = c;
+                                fnob     = nob;
+                        }
+                        break;
                 }
         }
 
         /* prefer the typed selection */
         conn = (typed != NULL) ? typed : fallback;
 
-#if SOCKNAL_ROUND_ROBIN
-        if (conn != NULL) {
-                /* round-robin all else being equal */
-                list_del (&conn->ksnc_list);
-                list_add_tail (&conn->ksnc_list, &peer->ksnp_conns);
-        }
-#endif
+        if (conn != NULL)
+                conn->ksnc_tx_last_post = cfs_time_current();
+
         return conn;
 }
 
 void
-ksocknal_next_mono_tx(ksock_conn_t *conn)
-{
-        ksock_tx_t     *tx = conn->ksnc_tx_mono;
-
-        /* Called holding BH lock: conn->ksnc_scheduler->kss_lock */
-        LASSERT(conn->ksnc_proto == &ksocknal_protocol_v2x);
-        LASSERT(!list_empty(&conn->ksnc_tx_queue));
-        LASSERT(tx != NULL);
-
-        if (tx->tx_list.next == &conn->ksnc_tx_queue) {
-                /* no more packets queued */
-                conn->ksnc_tx_mono = NULL;
-        } else {
-                conn->ksnc_tx_mono = list_entry(tx->tx_list.next, ksock_tx_t, tx_list);
-                LASSERT(conn->ksnc_tx_mono->tx_msg.ksm_type == tx->tx_msg.ksm_type);
-        }
-}
-
-int
-ksocknal_piggyback_zcack(ksock_conn_t *conn, __u64 cookie)
+ksocknal_tx_prep(ksock_conn_t *conn, ksock_tx_t *tx)
 {
-        ksock_tx_t     *tx = conn->ksnc_tx_mono;
-
-        /* Called holding BH lock: conn->ksnc_scheduler->kss_lock */
-
-        if (tx == NULL)
-                return 0;
-
-        if (tx->tx_msg.ksm_type == KSOCK_MSG_NOOP) {
-                /* tx is noop zc-ack, can't piggyback zc-ack cookie */
-                return 0;
-        }
-
-        LASSERT(tx->tx_msg.ksm_type == KSOCK_MSG_LNET);
-        LASSERT(tx->tx_msg.ksm_zc_ack_cookie == 0);
-
-        /* piggyback the zc-ack cookie */
-        tx->tx_msg.ksm_zc_ack_cookie = cookie;
-        ksocknal_next_mono_tx(conn);
+        conn->ksnc_proto->pro_pack(tx);
 
-        return 1;
+        cfs_atomic_add (tx->tx_nob, &conn->ksnc_tx_nob);
+        ksocknal_conn_addref(conn); /* +1 ref for tx */
+        tx->tx_conn = conn;
 }
 
 void
@@ -724,7 +690,7 @@ ksocknal_queue_tx_locked (ksock_tx_t *tx, ksock_conn_t *conn)
 {
         ksock_sched_t *sched = conn->ksnc_scheduler;
         ksock_msg_t   *msg = &tx->tx_msg;
-        ksock_tx_t    *ztx;
+        ksock_tx_t    *ztx = NULL;
         int            bufnob = 0;
 
         /* called holding global lock (read or irq-write) and caller may
@@ -733,13 +699,12 @@ ksocknal_queue_tx_locked (ksock_tx_t *tx, ksock_conn_t *conn)
          * ksnc_sock... */
         LASSERT(!conn->ksnc_closing);
 
-        CDEBUG (D_NET, "Sending to %s ip %d.%d.%d.%d:%d\n",
+        CDEBUG (D_NET, "Sending to %s ip %d.%d.%d.%d:%d\n", 
                 libcfs_id2str(conn->ksnc_peer->ksnp_id),
                 HIPQUAD(conn->ksnc_ipaddr),
                 conn->ksnc_port);
 
-        tx->tx_checked_zc = 0;
-        conn->ksnc_proto->pro_pack(tx);
+        ksocknal_tx_prep(conn, tx);
 
         /* Ensure the frags we've been given EXACTLY match the number of
          * bytes we want to send.  Many TCP/IP stacks disregard any total
@@ -748,118 +713,79 @@ ksocknal_queue_tx_locked (ksock_tx_t *tx, ksock_conn_t *conn)
          * We always expect at least 1 mapped fragment containing the
          * complete ksocknal message header. */
         LASSERT (lnet_iov_nob (tx->tx_niov, tx->tx_iov) +
-                 lnet_kiov_nob (tx->tx_nkiov, tx->tx_kiov) == tx->tx_nob);
+                 lnet_kiov_nob(tx->tx_nkiov, tx->tx_kiov) ==
+                 (unsigned int)tx->tx_nob);
         LASSERT (tx->tx_niov >= 1);
         LASSERT (tx->tx_resid == tx->tx_nob);
 
         CDEBUG (D_NET, "Packet %p type %d, nob %d niov %d nkiov %d\n",
-                tx, (tx->tx_lnetmsg != NULL)? tx->tx_lnetmsg->msg_hdr.type:
-                                              KSOCK_MSG_NOOP,
+                tx, (tx->tx_lnetmsg != NULL) ? tx->tx_lnetmsg->msg_hdr.type:
+                                               KSOCK_MSG_NOOP,
                 tx->tx_nob, tx->tx_niov, tx->tx_nkiov);
 
-        atomic_add (tx->tx_nob, &conn->ksnc_tx_nob);
-        tx->tx_conn = conn;
-        ksocknal_conn_addref(conn); /* +1 ref for tx */
-
-        /* 
-         * NB Darwin: SOCK_WMEM_QUEUED()->sock_getsockopt() will take
-         * a blockable lock(socket lock), so SOCK_WMEM_QUEUED can't be
-         * put in spinlock. 
+        /*
+         * FIXME: SOCK_WMEM_QUEUED and SOCK_ERROR could block in __DARWIN8__
+         * but they're used inside spinlocks a lot.
          */
-        bufnob = SOCK_WMEM_QUEUED(conn->ksnc_sock);
-        spin_lock_bh (&sched->kss_lock);
+        bufnob = libcfs_sock_wmem_queued(conn->ksnc_sock);
+        cfs_spin_lock_bh (&sched->kss_lock);
 
-        if (list_empty(&conn->ksnc_tx_queue) && bufnob == 0) {
+        if (cfs_list_empty(&conn->ksnc_tx_queue) && bufnob == 0) {
                 /* First packet starts the timeout */
                 conn->ksnc_tx_deadline =
                         cfs_time_shift(*ksocknal_tunables.ksnd_timeout);
+                if (conn->ksnc_tx_bufnob > 0) /* something got ACKed */
+                        conn->ksnc_peer->ksnp_last_alive = cfs_time_current();
                 conn->ksnc_tx_bufnob = 0;
-                mb();    /* order with adding to tx_queue */
+                cfs_mb(); /* order with adding to tx_queue */
         }
 
-        ztx = NULL;
-
         if (msg->ksm_type == KSOCK_MSG_NOOP) {
                 /* The packet is noop ZC ACK, try to piggyback the ack_cookie
                  * on a normal packet so I don't need to send it */
-                LASSERT(msg->ksm_zc_req_cookie == 0);
-                LASSERT(msg->ksm_zc_ack_cookie != 0);
-
-                if (conn->ksnc_tx_mono != NULL) {
-                        if (ksocknal_piggyback_zcack(conn, msg->ksm_zc_ack_cookie)) {
-                                /* zc-ack cookie is piggybacked */
-                                atomic_sub (tx->tx_nob, &conn->ksnc_tx_nob);
-                                ztx = tx;       /* Put to freelist later */
-                        } else {
-                                /* no packet can piggyback zc-ack cookie */
-                                list_add_tail (&tx->tx_list, &conn->ksnc_tx_queue);
-                        }
-                } else {
-                        /* It's the first mono-packet */
-                        conn->ksnc_tx_mono = tx;
-                        list_add_tail (&tx->tx_list, &conn->ksnc_tx_queue);
-                }
+                LASSERT (msg->ksm_zc_cookies[1] != 0);
+                LASSERT (conn->ksnc_proto->pro_queue_tx_zcack != NULL);
+
+                if (conn->ksnc_proto->pro_queue_tx_zcack(conn, tx, 0))
+                        ztx = tx; /* ZC ACK piggybacked on ztx release tx later */
 
         } else {
                 /* It's a normal packet - can it piggback a noop zc-ack that
                  * has been queued already? */
-                LASSERT(msg->ksm_zc_ack_cookie == 0);
-
-                if (conn->ksnc_proto == &ksocknal_protocol_v2x &&  /* V2.x packet */
-                    conn->ksnc_tx_mono != NULL) {
-                        if (conn->ksnc_tx_mono->tx_msg.ksm_type == KSOCK_MSG_NOOP) {
-                                /* There is a noop zc-ack can be piggybacked */
-                                ztx = conn->ksnc_tx_mono;
+                LASSERT (msg->ksm_zc_cookies[1] == 0);
+                LASSERT (conn->ksnc_proto->pro_queue_tx_msg != NULL);
 
-                                msg->ksm_zc_ack_cookie = ztx->tx_msg.ksm_zc_ack_cookie;
-                                ksocknal_next_mono_tx(conn);
-
-                                /* use tx to replace the noop zc-ack packet, ztx will
-                                 * be put to freelist later */
-                                list_add(&tx->tx_list, &ztx->tx_list);
-                                list_del(&ztx->tx_list);
-
-                                atomic_sub (ztx->tx_nob, &conn->ksnc_tx_nob);
-                        } else {
-                                /* no noop zc-ack packet, just enqueue it */
-                                LASSERT(conn->ksnc_tx_mono->tx_msg.ksm_type == KSOCK_MSG_LNET);
-                                list_add_tail (&tx->tx_list, &conn->ksnc_tx_queue);
-                        }
-
-                } else if (conn->ksnc_proto == &ksocknal_protocol_v2x) {
-                        /* it's the first mono-packet, enqueue it */
-                        conn->ksnc_tx_mono = tx;
-                        list_add_tail (&tx->tx_list, &conn->ksnc_tx_queue);
-                } else {
-                        /* V1.x packet, just enqueue it */
-                        list_add_tail (&tx->tx_list, &conn->ksnc_tx_queue);
-                }
+                ztx = conn->ksnc_proto->pro_queue_tx_msg(conn, tx);
+                /* ztx will be released later */
         }
 
-        if (ztx != NULL)
-                list_add_tail(&ztx->tx_list, &sched->kss_zombie_noop_txs);
+        if (ztx != NULL) {
+                cfs_atomic_sub (ztx->tx_nob, &conn->ksnc_tx_nob);
+                cfs_list_add_tail(&ztx->tx_list, &sched->kss_zombie_noop_txs);
+        }
 
         if (conn->ksnc_tx_ready &&      /* able to send */
             !conn->ksnc_tx_scheduled) { /* not scheduled to send */
                 /* +1 ref for scheduler */
                 ksocknal_conn_addref(conn);
-                list_add_tail (&conn->ksnc_tx_list,
-                               &sched->kss_tx_conns);
+                cfs_list_add_tail (&conn->ksnc_tx_list,
+                                   &sched->kss_tx_conns);
                 conn->ksnc_tx_scheduled = 1;
                 cfs_waitq_signal (&sched->kss_waitq);
         }
 
-        spin_unlock_bh (&sched->kss_lock);
+        cfs_spin_unlock_bh (&sched->kss_lock);
 }
 
+
 ksock_route_t *
 ksocknal_find_connectable_route_locked (ksock_peer_t *peer)
 {
-        struct list_head  *tmp;
+        cfs_list_t        *tmp;
         ksock_route_t     *route;
 
-        list_for_each (tmp, &peer->ksnp_routes) {
-                route = list_entry (tmp, ksock_route_t, ksnr_list);
+        cfs_list_for_each (tmp, &peer->ksnp_routes) {
+                route = cfs_list_entry (tmp, ksock_route_t, ksnr_list);
 
                 LASSERT (!route->ksnr_connecting || route->ksnr_scheduled);
 
@@ -885,11 +811,11 @@ ksocknal_find_connectable_route_locked (ksock_peer_t *peer)
 ksock_route_t *
 ksocknal_find_connecting_route_locked (ksock_peer_t *peer)
 {
-        struct list_head  *tmp;
+        cfs_list_t        *tmp;
         ksock_route_t     *route;
 
-        list_for_each (tmp, &peer->ksnp_routes) {
-                route = list_entry (tmp, ksock_route_t, ksnr_list);
+        cfs_list_for_each (tmp, &peer->ksnp_routes) {
+                route = cfs_list_entry (tmp, ksock_route_t, ksnr_list);
 
                 LASSERT (!route->ksnr_connecting || route->ksnr_scheduled);
 
@@ -905,44 +831,41 @@ ksocknal_launch_packet (lnet_ni_t *ni, ksock_tx_t *tx, lnet_process_id_t id)
 {
         ksock_peer_t     *peer;
         ksock_conn_t     *conn;
-        ksock_route_t    *route;
-        rwlock_t         *g_lock;
+        cfs_rwlock_t     *g_lock;
         int               retry;
         int               rc;
 
         LASSERT (tx->tx_conn == NULL);
-        LASSERT (tx->tx_lnetmsg != NULL);
 
         g_lock = &ksocknal_data.ksnd_global_lock;
 
         for (retry = 0;; retry = 1) {
-#if !SOCKNAL_ROUND_ROBIN
-                read_lock (g_lock);
+                cfs_read_lock (g_lock);
                 peer = ksocknal_find_peer_locked(ni, id);
                 if (peer != NULL) {
                         if (ksocknal_find_connectable_route_locked(peer) == NULL) {
-                                conn = ksocknal_find_conn_locked (tx->tx_lnetmsg->msg_len, peer);
+                                conn = ksocknal_find_conn_locked(peer, tx, tx->tx_nonblk);
                                 if (conn != NULL) {
                                         /* I've got no routes that need to be
                                          * connecting and I do have an actual
                                          * connection... */
                                         ksocknal_queue_tx_locked (tx, conn);
-                                        read_unlock (g_lock);
+                                        cfs_read_unlock (g_lock);
                                         return (0);
                                 }
                         }
                 }
 
                 /* I'll need a write lock... */
-                read_unlock (g_lock);
-#endif
-                write_lock_bh (g_lock);
+                cfs_read_unlock (g_lock);
+
+                cfs_write_lock_bh (g_lock);
 
                 peer = ksocknal_find_peer_locked(ni, id);
                 if (peer != NULL)
                         break;
 
-                write_unlock_bh (g_lock);
+                cfs_write_unlock_bh (g_lock);
 
                 if ((id.pid & LNET_PID_USERFLAG) != 0) {
                         CERROR("Refusing to create a connection to "
@@ -965,20 +888,13 @@ ksocknal_launch_packet (lnet_ni_t *ni, ksock_tx_t *tx, lnet_process_id_t id)
                 }
         }
 
-        for (;;) {
-                /* launch any/all connections that need it */
-                route = ksocknal_find_connectable_route_locked (peer);
-                if (route == NULL)
-                        break;
-
-                ksocknal_launch_connection_locked (route);
-        }
+        ksocknal_launch_all_connections_locked(peer);
 
-        conn = ksocknal_find_conn_locked (tx->tx_lnetmsg->msg_len, peer);
+        conn = ksocknal_find_conn_locked(peer, tx, tx->tx_nonblk);
         if (conn != NULL) {
                 /* Connection exists; queue message on it */
                 ksocknal_queue_tx_locked (tx, conn);
-                write_unlock_bh (g_lock);
+                cfs_write_unlock_bh (g_lock);
                 return (0);
         }
 
@@ -987,14 +903,14 @@ ksocknal_launch_packet (lnet_ni_t *ni, ksock_tx_t *tx, lnet_process_id_t id)
                 /* the message is going to be pinned to the peer */
                 tx->tx_deadline =
                         cfs_time_shift(*ksocknal_tunables.ksnd_timeout);
-                
+
                 /* Queue the message until a connection is established */
-                list_add_tail (&tx->tx_list, &peer->ksnp_tx_queue);
-                write_unlock_bh (g_lock);
+                cfs_list_add_tail (&tx->tx_list, &peer->ksnp_tx_queue);
+                cfs_write_unlock_bh (g_lock);
                 return 0;
         }
 
-        write_unlock_bh (g_lock);
+        cfs_write_unlock_bh (g_lock);
 
         /* NB Routes may be ignored if connections to them failed recently */
         CDEBUG(D_NETERROR, "No usable routes to %s\n", libcfs_id2str(id));
@@ -1025,7 +941,7 @@ ksocknal_send(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg)
         LASSERT (payload_niov <= LNET_MAX_IOV);
         /* payload is either all vaddrs or all pages */
         LASSERT (!(payload_kiov != NULL && payload_iov != NULL));
-        LASSERT (!in_interrupt ());
+        LASSERT (!cfs_in_interrupt ());
 
         if (payload_iov != NULL)
                 desc_size = offsetof(ksock_tx_t,
@@ -1034,7 +950,7 @@ ksocknal_send(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg)
                 desc_size = offsetof(ksock_tx_t,
                                      tx_frags.paged.kiov[payload_niov]);
 
-        tx = ksocknal_alloc_tx(desc_size);
+        tx = ksocknal_alloc_tx(KSOCK_MSG_LNET, desc_size);
         if (tx == NULL) {
                 CERROR("Can't allocate tx desc type %d size %d\n",
                        type, desc_size);
@@ -1059,9 +975,12 @@ ksocknal_send(lnet_ni_t *ni, void *private, lnet_msg_t *lntmsg)
                 tx->tx_nkiov = lnet_extract_kiov(payload_niov, tx->tx_kiov,
                                                  payload_niov, payload_kiov,
                                                  payload_offset, payload_nob);
+
+                if (payload_nob >= *ksocknal_tunables.ksnd_zc_min_payload)
+                        tx->tx_zc_capable = 1;
         }
 
-        ksocknal_init_msg(&tx->tx_msg, KSOCK_MSG_LNET);
+        socklnd_init_msg(&tx->tx_msg, KSOCK_MSG_LNET);
 
         /* The first fragment will be set later in pro_pack */
         rc = ksocknal_launch_packet(ni, tx, target);
@@ -1080,18 +999,18 @@ ksocknal_thread_start (int (*fn)(void *arg), void *arg)
         if (pid < 0)
                 return ((int)pid);
 
-        write_lock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_lock_bh (&ksocknal_data.ksnd_global_lock);
         ksocknal_data.ksnd_nthreads++;
-        write_unlock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_unlock_bh (&ksocknal_data.ksnd_global_lock);
         return (0);
 }
 
 void
 ksocknal_thread_fini (void)
 {
-        write_lock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_lock_bh (&ksocknal_data.ksnd_global_lock);
         ksocknal_data.ksnd_nthreads--;
-        write_unlock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_unlock_bh (&ksocknal_data.ksnd_global_lock);
 }
 
 int
@@ -1112,10 +1031,11 @@ ksocknal_new_packet (ksock_conn_t *conn, int nob_to_skip)
 
         if (nob_to_skip == 0) {         /* right at next packet boundary now */
                 conn->ksnc_rx_started = 0;
-                mb ();                          /* racing with timeout thread */
+                cfs_mb();                       /* racing with timeout thread */
 
                 switch (conn->ksnc_proto->pro_version) {
                 case  KSOCK_PROTO_V2:
+                case  KSOCK_PROTO_V3:
                         conn->ksnc_rx_state = SOCKNAL_RX_KSM_HEADER;
                         conn->ksnc_rx_iov = (struct iovec *)&conn->ksnc_rx_iov_space;
                         conn->ksnc_rx_iov[0].iov_base = (char *)&conn->ksnc_msg;
@@ -1175,101 +1095,14 @@ ksocknal_new_packet (ksock_conn_t *conn, int nob_to_skip)
         return (0);
 }
 
-/* (Sink) handle incoming ZC request from sender */
-static int
-ksocknal_handle_zc_req(ksock_peer_t *peer, __u64 cookie)
-{
-        ksock_conn_t   *conn;
-        ksock_tx_t     *tx;
-        ksock_sched_t  *sched;
-        int             rc;
-
-        read_lock (&ksocknal_data.ksnd_global_lock);
-
-        conn = ksocknal_find_conn_locked (0, peer);
-        if (conn == NULL) {
-                read_unlock (&ksocknal_data.ksnd_global_lock);
-                CERROR("Can't find connection to send zcack.\n");
-                return -ECONNRESET;
-        }
-
-        sched = conn->ksnc_scheduler;
-
-        spin_lock_bh (&sched->kss_lock);
-        rc = ksocknal_piggyback_zcack(conn, cookie);
-        spin_unlock_bh (&sched->kss_lock);
-
-        read_unlock (&ksocknal_data.ksnd_global_lock);
-        if (rc) {
-                /* Ack cookie is piggybacked */
-                return 0;
-        }
-
-        tx = ksocknal_alloc_tx(KSOCK_NOOP_TX_SIZE);
-        if (tx == NULL) {
-                CERROR("Can't allocate noop tx desc\n");
-                return -ENOMEM;
-        }
-
-        tx->tx_conn     = NULL;
-        tx->tx_lnetmsg  = NULL;
-        tx->tx_kiov     = NULL;
-        tx->tx_nkiov    = 0;
-        tx->tx_iov      = tx->tx_frags.virt.iov;
-        tx->tx_niov     = 1;
-
-        ksocknal_init_msg(&tx->tx_msg, KSOCK_MSG_NOOP);
-        tx->tx_msg.ksm_zc_ack_cookie = cookie; /* incoming cookie */
-
-        read_lock (&ksocknal_data.ksnd_global_lock);
-
-        conn = ksocknal_find_conn_locked (0, peer);
-        if (conn == NULL) {
-                read_unlock (&ksocknal_data.ksnd_global_lock);
-                ksocknal_free_tx(tx);
-                CERROR("Can't find connection to send zcack.\n");
-                return -ECONNRESET;
-        }
-        ksocknal_queue_tx_locked(tx, conn);
-
-        read_unlock (&ksocknal_data.ksnd_global_lock);
-
-        return 0;
-}
-
-/* (Sender) handle ZC_ACK from sink */
-static int
-ksocknal_handle_zc_ack(ksock_peer_t *peer, __u64 cookie)
-{
-        ksock_tx_t             *tx;
-        struct list_head       *ctmp;
-
-        spin_lock(&peer->ksnp_lock);
-
-        list_for_each(ctmp, &peer->ksnp_zc_req_list) {
-                tx = list_entry (ctmp, ksock_tx_t, tx_zc_list);
-                if (tx->tx_msg.ksm_zc_req_cookie != cookie)
-                        continue;
-
-                tx->tx_msg.ksm_zc_req_cookie = 0;
-                list_del(&tx->tx_zc_list);
-
-                spin_unlock(&peer->ksnp_lock);
-
-                ksocknal_tx_decref(tx);
-                return 0;
-        }
-        spin_unlock(&peer->ksnp_lock);
-
-        return -EPROTO;
-}
-
 int
 ksocknal_process_receive (ksock_conn_t *conn)
 {
-        int           rc;
+        lnet_hdr_t        *lhdr;
+        lnet_process_id_t *id;
+        int                rc;
 
-        LASSERT (atomic_read(&conn->ksnc_conn_refcount) > 0);
+        LASSERT (cfs_atomic_read(&conn->ksnc_conn_refcount) > 0);
 
         /* NB: sched lock NOT held */
         /* SOCKNAL_RX_LNET_HEADER is here for backward compatability */
@@ -1314,8 +1147,18 @@ ksocknal_process_receive (ksock_conn_t *conn)
                 if (conn->ksnc_flip) {
                         __swab32s(&conn->ksnc_msg.ksm_type);
                         __swab32s(&conn->ksnc_msg.ksm_csum);
-                        __swab64s(&conn->ksnc_msg.ksm_zc_req_cookie);
-                        __swab64s(&conn->ksnc_msg.ksm_zc_ack_cookie);
+                        __swab64s(&conn->ksnc_msg.ksm_zc_cookies[0]);
+                        __swab64s(&conn->ksnc_msg.ksm_zc_cookies[1]);
+                }
+
+                if (conn->ksnc_msg.ksm_type != KSOCK_MSG_NOOP &&
+                    conn->ksnc_msg.ksm_type != KSOCK_MSG_LNET) {
+                        CERROR("%s: Unknown message type: %x\n",
+                               libcfs_id2str(conn->ksnc_peer->ksnp_id),
+                               conn->ksnc_msg.ksm_type);
+                        ksocknal_new_packet(conn, 0);
+                        ksocknal_close_conn_and_siblings(conn, -EPROTO);
+                        return (-EPROTO);
                 }
 
                 if (conn->ksnc_msg.ksm_type == KSOCK_MSG_NOOP &&
@@ -1330,15 +1173,21 @@ ksocknal_process_receive (ksock_conn_t *conn)
                         return (-EIO);
                 }
 
-                if (conn->ksnc_msg.ksm_zc_ack_cookie != 0) {
-                        LASSERT(conn->ksnc_proto == &ksocknal_protocol_v2x);
+                if (conn->ksnc_msg.ksm_zc_cookies[1] != 0) {
+                        __u64 cookie = 0;
+
+                        LASSERT (conn->ksnc_proto != &ksocknal_protocol_v1x);
+
+                        if (conn->ksnc_msg.ksm_type == KSOCK_MSG_NOOP)
+                                cookie = conn->ksnc_msg.ksm_zc_cookies[0];
+
+                        rc = conn->ksnc_proto->pro_handle_zcack(conn, cookie,
+                                               conn->ksnc_msg.ksm_zc_cookies[1]);
 
-                        rc = ksocknal_handle_zc_ack(conn->ksnc_peer,
-                                                    conn->ksnc_msg.ksm_zc_ack_cookie);
                         if (rc != 0) {
-                                CERROR("%s: Unknown zero copy ACK cookie: "LPU64"\n",
+                                CERROR("%s: Unknown ZC-ACK cookie: "LPU64", "LPU64"\n",
                                        libcfs_id2str(conn->ksnc_peer->ksnp_id),
-                                       conn->ksnc_msg.ksm_zc_ack_cookie);
+                                       cookie, conn->ksnc_msg.ksm_zc_cookies[1]);
                                 ksocknal_new_packet(conn, 0);
                                 ksocknal_close_conn_and_siblings(conn, -EPROTO);
                                 return (rc);
@@ -1349,7 +1198,6 @@ ksocknal_process_receive (ksock_conn_t *conn)
                         ksocknal_new_packet (conn, 0);
                         return 0;       /* NOOP is done and just return */
                 }
-                LASSERT (conn->ksnc_msg.ksm_type == KSOCK_MSG_LNET);
 
                 conn->ksnc_rx_state = SOCKNAL_RX_LNET_HEADER;
                 conn->ksnc_rx_nob_wanted = sizeof(ksock_lnet_msg_t);
@@ -1371,8 +1219,8 @@ ksocknal_process_receive (ksock_conn_t *conn)
 
                 if ((conn->ksnc_peer->ksnp_id.pid & LNET_PID_USERFLAG) != 0) {
                         /* Userspace peer */
-                        lnet_process_id_t *id = &conn->ksnc_peer->ksnp_id;
-                        lnet_hdr_t        *lhdr = &conn->ksnc_msg.ksm_u.lnetmsg.ksnm_hdr;
+                        lhdr = &conn->ksnc_msg.ksm_u.lnetmsg.ksnm_hdr;
+                        id   = &conn->ksnc_peer->ksnp_id;
 
                         /* Substitute process ID assigned at connection time */
                         lhdr->src_pid = cpu_to_le32(id->pid);
@@ -1416,14 +1264,19 @@ ksocknal_process_receive (ksock_conn_t *conn)
                         rc = -EIO;
                 }
 
-                lnet_finalize(conn->ksnc_peer->ksnp_ni, conn->ksnc_cookie, rc);
+                if (rc == 0 && conn->ksnc_msg.ksm_zc_cookies[0] != 0) {
+                        LASSERT(conn->ksnc_proto != &ksocknal_protocol_v1x);
 
-                if (rc == 0 && conn->ksnc_msg.ksm_zc_req_cookie != 0) {
-                        LASSERT(conn->ksnc_proto == &ksocknal_protocol_v2x);
-                        rc = ksocknal_handle_zc_req(conn->ksnc_peer,
-                                                    conn->ksnc_msg.ksm_zc_req_cookie);
+                        lhdr = &conn->ksnc_msg.ksm_u.lnetmsg.ksnm_hdr;
+                        id   = &conn->ksnc_peer->ksnp_id;
+
+                        rc = conn->ksnc_proto->pro_handle_zcreq(conn,
+                                               conn->ksnc_msg.ksm_zc_cookies[0],
+                                               le64_to_cpu(lhdr->src_nid) != id->nid);
                 }
 
+                lnet_finalize(conn->ksnc_peer->ksnp_ni, conn->ksnc_cookie, rc);
+
                 if (rc != 0) {
                         ksocknal_new_packet(conn, 0);
                         ksocknal_close_conn_and_siblings (conn, rc);
@@ -1483,11 +1336,11 @@ ksocknal_recv (lnet_ni_t *ni, void *private, lnet_msg_t *msg, int delayed,
 
         LASSERT (conn->ksnc_rx_scheduled);
 
-        spin_lock_bh (&sched->kss_lock);
+        cfs_spin_lock_bh (&sched->kss_lock);
 
         switch (conn->ksnc_rx_state) {
         case SOCKNAL_RX_PARSE_WAIT:
-                list_add_tail(&conn->ksnc_rx_list, &sched->kss_rx_conns);
+                cfs_list_add_tail(&conn->ksnc_rx_list, &sched->kss_rx_conns);
                 cfs_waitq_signal (&sched->kss_waitq);
                 LASSERT (conn->ksnc_rx_ready);
                 break;
@@ -1499,7 +1352,7 @@ ksocknal_recv (lnet_ni_t *ni, void *private, lnet_msg_t *msg, int delayed,
 
         conn->ksnc_rx_state = SOCKNAL_RX_LNET_PAYLOAD;
 
-        spin_unlock_bh (&sched->kss_lock);
+        cfs_spin_unlock_bh (&sched->kss_lock);
         ksocknal_conn_decref(conn);
         return (0);
 }
@@ -1509,13 +1362,13 @@ ksocknal_sched_cansleep(ksock_sched_t *sched)
 {
         int           rc;
 
-        spin_lock_bh (&sched->kss_lock);
+        cfs_spin_lock_bh (&sched->kss_lock);
 
         rc = (!ksocknal_data.ksnd_shuttingdown &&
-              list_empty(&sched->kss_rx_conns) &&
-              list_empty(&sched->kss_tx_conns));
+              cfs_list_empty(&sched->kss_rx_conns) &&
+              cfs_list_empty(&sched->kss_tx_conns));
 
-        spin_unlock_bh (&sched->kss_lock);
+        cfs_spin_unlock_bh (&sched->kss_lock);
         return (rc);
 }
 
@@ -1526,35 +1379,27 @@ int ksocknal_scheduler (void *arg)
         ksock_tx_t        *tx;
         int                rc;
         int                nloops = 0;
-        int                id = sched - ksocknal_data.ksnd_schedulers;
+        int                id = (int)(sched - ksocknal_data.ksnd_schedulers);
         char               name[16];
 
         snprintf (name, sizeof (name),"socknal_sd%02d", id);
         cfs_daemonize (name);
         cfs_block_allsigs ();
 
-#if defined(CONFIG_SMP) && defined(CPU_AFFINITY)
-        id = ksocknal_sched2cpu(id);
-        if (cpu_online(id)) {
-                cpumask_t m = CPU_MASK_NONE;
-                cpu_set(id, m);
-                set_cpus_allowed(current, m);
-        } else {
+        if (ksocknal_lib_bind_thread_to_cpu(id))
                 CERROR ("Can't set CPU affinity for %s to %d\n", name, id);
-        }
-#endif /* CONFIG_SMP && CPU_AFFINITY */
 
-        spin_lock_bh (&sched->kss_lock);
+        cfs_spin_lock_bh (&sched->kss_lock);
 
         while (!ksocknal_data.ksnd_shuttingdown) {
                 int did_something = 0;
 
                 /* Ensure I progress everything semi-fairly */
 
-                if (!list_empty (&sched->kss_rx_conns)) {
-                        conn = list_entry(sched->kss_rx_conns.next,
-                                          ksock_conn_t, ksnc_rx_list);
-                        list_del(&conn->ksnc_rx_list);
+                if (!cfs_list_empty (&sched->kss_rx_conns)) {
+                        conn = cfs_list_entry(sched->kss_rx_conns.next,
+                                              ksock_conn_t, ksnc_rx_list);
+                        cfs_list_del(&conn->ksnc_rx_list);
 
                         LASSERT(conn->ksnc_rx_scheduled);
                         LASSERT(conn->ksnc_rx_ready);
@@ -1564,11 +1409,11 @@ int ksocknal_scheduler (void *arg)
                          * data_ready can set it any time after we release
                          * kss_lock. */
                         conn->ksnc_rx_ready = 0;
-                        spin_unlock_bh (&sched->kss_lock);
+                        cfs_spin_unlock_bh (&sched->kss_lock);
 
                         rc = ksocknal_process_receive(conn);
 
-                        spin_lock_bh (&sched->kss_lock);
+                        cfs_spin_lock_bh (&sched->kss_lock);
 
                         /* I'm the only one that can clear this flag */
                         LASSERT(conn->ksnc_rx_scheduled);
@@ -1584,8 +1429,8 @@ int ksocknal_scheduler (void *arg)
                                 conn->ksnc_rx_state = SOCKNAL_RX_PARSE_WAIT;
                         } else if (conn->ksnc_rx_ready) {
                                 /* reschedule for rx */
-                                list_add_tail (&conn->ksnc_rx_list,
-                                               &sched->kss_rx_conns);
+                                cfs_list_add_tail (&conn->ksnc_rx_list,
+                                                   &sched->kss_rx_conns);
                         } else {
                                 conn->ksnc_rx_scheduled = 0;
                                 /* drop my ref */
@@ -1595,39 +1440,40 @@ int ksocknal_scheduler (void *arg)
                         did_something = 1;
                 }
 
-                if (!list_empty (&sched->kss_tx_conns)) {
+                if (!cfs_list_empty (&sched->kss_tx_conns)) {
                         CFS_LIST_HEAD    (zlist);
 
-                        if (!list_empty(&sched->kss_zombie_noop_txs)) {
-                                list_add(&zlist, &sched->kss_zombie_noop_txs);
-                                list_del_init(&sched->kss_zombie_noop_txs);
+                        if (!cfs_list_empty(&sched->kss_zombie_noop_txs)) {
+                                cfs_list_add(&zlist,
+                                             &sched->kss_zombie_noop_txs);
+                                cfs_list_del_init(&sched->kss_zombie_noop_txs);
                         }
 
-                        conn = list_entry(sched->kss_tx_conns.next,
-                                          ksock_conn_t, ksnc_tx_list);
-                        list_del (&conn->ksnc_tx_list);
+                        conn = cfs_list_entry(sched->kss_tx_conns.next,
+                                              ksock_conn_t, ksnc_tx_list);
+                        cfs_list_del (&conn->ksnc_tx_list);
 
                         LASSERT(conn->ksnc_tx_scheduled);
                         LASSERT(conn->ksnc_tx_ready);
-                        LASSERT(!list_empty(&conn->ksnc_tx_queue));
+                        LASSERT(!cfs_list_empty(&conn->ksnc_tx_queue));
 
-                        tx = list_entry(conn->ksnc_tx_queue.next,
-                                        ksock_tx_t, tx_list);
+                        tx = cfs_list_entry(conn->ksnc_tx_queue.next,
+                                            ksock_tx_t, tx_list);
 
-                        if (conn->ksnc_tx_mono == tx)
-                                ksocknal_next_mono_tx(conn);
+                        if (conn->ksnc_tx_carrier == tx)
+                                ksocknal_next_tx_carrier(conn);
 
                         /* dequeue now so empty list => more to send */
-                        list_del(&tx->tx_list);
+                        cfs_list_del(&tx->tx_list);
 
                         /* Clear tx_ready in case send isn't complete.  Do
                          * it BEFORE we call process_transmit, since
                          * write_space can set it any time after we release
                          * kss_lock. */
                         conn->ksnc_tx_ready = 0;
-                        spin_unlock_bh (&sched->kss_lock);
+                        cfs_spin_unlock_bh (&sched->kss_lock);
 
-                        if (!list_empty(&zlist)) {
+                        if (!cfs_list_empty(&zlist)) {
                                 /* free zombie noop txs, it's fast because 
                                  * noop txs are just put in freelist */
                                 ksocknal_txlist_done(NULL, &zlist, 0);
@@ -1637,13 +1483,14 @@ int ksocknal_scheduler (void *arg)
 
                         if (rc == -ENOMEM || rc == -EAGAIN) {
                                 /* Incomplete send: replace tx on HEAD of tx_queue */
-                                spin_lock_bh (&sched->kss_lock);
-                                list_add (&tx->tx_list, &conn->ksnc_tx_queue);
+                                cfs_spin_lock_bh (&sched->kss_lock);
+                                cfs_list_add (&tx->tx_list,
+                                              &conn->ksnc_tx_queue);
                         } else {
                                 /* Complete send; tx -ref */
                                 ksocknal_tx_decref (tx);
 
-                                spin_lock_bh (&sched->kss_lock);
+                                cfs_spin_lock_bh (&sched->kss_lock);
                                 /* assume space for more */
                                 conn->ksnc_tx_ready = 1;
                         }
@@ -1652,10 +1499,10 @@ int ksocknal_scheduler (void *arg)
                                 /* Do nothing; after a short timeout, this
                                  * conn will be reposted on kss_tx_conns. */
                         } else if (conn->ksnc_tx_ready &&
-                                   !list_empty (&conn->ksnc_tx_queue)) {
+                                   !cfs_list_empty (&conn->ksnc_tx_queue)) {
                                 /* reschedule for tx */
-                                list_add_tail (&conn->ksnc_tx_list,
-                                               &sched->kss_tx_conns);
+                                cfs_list_add_tail (&conn->ksnc_tx_list,
+                                                   &sched->kss_tx_conns);
                         } else {
                                 conn->ksnc_tx_scheduled = 0;
                                 /* drop my ref */
@@ -1666,24 +1513,24 @@ int ksocknal_scheduler (void *arg)
                 }
                 if (!did_something ||           /* nothing to do */
                     ++nloops == SOCKNAL_RESCHED) { /* hogging CPU? */
-                        spin_unlock_bh (&sched->kss_lock);
+                        cfs_spin_unlock_bh (&sched->kss_lock);
 
                         nloops = 0;
 
                         if (!did_something) {   /* wait for something to do */
-                                rc = wait_event_interruptible_exclusive(
+                                cfs_wait_event_interruptible_exclusive(
                                         sched->kss_waitq,
-                                        !ksocknal_sched_cansleep(sched));
+                                        !ksocknal_sched_cansleep(sched), rc);
                                 LASSERT (rc == 0);
                         } else {
-                                our_cond_resched();
+                                cfs_cond_resched();
                         }
 
-                        spin_lock_bh (&sched->kss_lock);
+                        cfs_spin_lock_bh (&sched->kss_lock);
                 }
         }
 
-        spin_unlock_bh (&sched->kss_lock);
+        cfs_spin_unlock_bh (&sched->kss_lock);
         ksocknal_thread_fini ();
         return (0);
 }
@@ -1699,20 +1546,20 @@ void ksocknal_read_callback (ksock_conn_t *conn)
 
         sched = conn->ksnc_scheduler;
 
-        spin_lock_bh (&sched->kss_lock);
+        cfs_spin_lock_bh (&sched->kss_lock);
 
         conn->ksnc_rx_ready = 1;
 
         if (!conn->ksnc_rx_scheduled) {  /* not being progressed */
-                list_add_tail(&conn->ksnc_rx_list,
-                              &sched->kss_rx_conns);
+                cfs_list_add_tail(&conn->ksnc_rx_list,
+                                  &sched->kss_rx_conns);
                 conn->ksnc_rx_scheduled = 1;
                 /* extra ref for scheduler */
                 ksocknal_conn_addref(conn);
 
                 cfs_waitq_signal (&sched->kss_waitq);
         }
-        spin_unlock_bh (&sched->kss_lock);
+        cfs_spin_unlock_bh (&sched->kss_lock);
 
         EXIT;
 }
@@ -1728,14 +1575,14 @@ void ksocknal_write_callback (ksock_conn_t *conn)
 
         sched = conn->ksnc_scheduler;
 
-        spin_lock_bh (&sched->kss_lock);
+        cfs_spin_lock_bh (&sched->kss_lock);
 
         conn->ksnc_tx_ready = 1;
 
-        if (!conn->ksnc_tx_scheduled && // not being progressed 
-            !list_empty(&conn->ksnc_tx_queue)){//packets to send 
-                list_add_tail (&conn->ksnc_tx_list,
-                               &sched->kss_tx_conns);
+        if (!conn->ksnc_tx_scheduled && // not being progressed
+            !cfs_list_empty(&conn->ksnc_tx_queue)){//packets to send
+                cfs_list_add_tail (&conn->ksnc_tx_list,
+                                   &sched->kss_tx_conns);
                 conn->ksnc_tx_scheduled = 1;
                 /* extra ref for scheduler */
                 ksocknal_conn_addref(conn);
@@ -1743,7 +1590,7 @@ void ksocknal_write_callback (ksock_conn_t *conn)
                 cfs_waitq_signal (&sched->kss_waitq);
         }
 
-        spin_unlock_bh (&sched->kss_lock);
+        cfs_spin_unlock_bh (&sched->kss_lock);
 
         EXIT;
 }
@@ -1751,15 +1598,29 @@ void ksocknal_write_callback (ksock_conn_t *conn)
 ksock_proto_t *
 ksocknal_parse_proto_version (ksock_hello_msg_t *hello)
 {
-        if ((hello->kshm_magic   == LNET_PROTO_MAGIC &&
-             hello->kshm_version == KSOCK_PROTO_V2) ||
-            (hello->kshm_magic   == __swab32(LNET_PROTO_MAGIC) &&
-             hello->kshm_version == __swab32(KSOCK_PROTO_V2))) {
+        __u32   version = 0;
+
+        if (hello->kshm_magic == LNET_PROTO_MAGIC)
+                version = hello->kshm_version;
+        else if (hello->kshm_magic == __swab32(LNET_PROTO_MAGIC))
+                version = __swab32(hello->kshm_version);
+
+        if (version != 0) {
 #if SOCKNAL_VERSION_DEBUG
-                if (*ksocknal_tunables.ksnd_protocol != 2)
+                if (*ksocknal_tunables.ksnd_protocol == 1)
+                        return NULL;
+
+                if (*ksocknal_tunables.ksnd_protocol == 2 &&
+                    version == KSOCK_PROTO_V3)
                         return NULL;
 #endif
-                return &ksocknal_protocol_v2x;
+                if (version == KSOCK_PROTO_V2)
+                        return &ksocknal_protocol_v2x;
+
+                if (version == KSOCK_PROTO_V3)
+                        return &ksocknal_protocol_v3x;
+
+                return NULL;
         }
 
         if (hello->kshm_magic == le32_to_cpu(LNET_PROTO_TCP_MAGIC)) {
@@ -1776,333 +1637,6 @@ ksocknal_parse_proto_version (ksock_hello_msg_t *hello)
         return NULL;
 }
 
-static int
-ksocknal_send_hello_v1 (ksock_conn_t *conn, ksock_hello_msg_t *hello)
-{
-        cfs_socket_t        *sock = conn->ksnc_sock;
-        lnet_hdr_t          *hdr;
-        lnet_magicversion_t *hmv;
-        int                  rc;
-        int                  i;
-
-        CLASSERT(sizeof(lnet_magicversion_t) == offsetof(lnet_hdr_t, src_nid));
-
-        LIBCFS_ALLOC(hdr, sizeof(*hdr));
-        if (hdr == NULL) {
-                CERROR("Can't allocate lnet_hdr_t\n");
-                return -ENOMEM;
-        }
-
-        hmv = (lnet_magicversion_t *)&hdr->dest_nid;
-
-        /* Re-organize V2.x message header to V1.x (lnet_hdr_t)
-         * header and send out */
-        hmv->magic         = cpu_to_le32 (LNET_PROTO_TCP_MAGIC);
-        hmv->version_major = cpu_to_le16 (KSOCK_PROTO_V1_MAJOR);
-        hmv->version_minor = cpu_to_le16 (KSOCK_PROTO_V1_MINOR);
-
-        if (the_lnet.ln_testprotocompat != 0) {
-                /* single-shot proto check */
-                LNET_LOCK();
-                if ((the_lnet.ln_testprotocompat & 1) != 0) {
-                        hmv->version_major++;   /* just different! */
-                        the_lnet.ln_testprotocompat &= ~1;
-                }
-                if ((the_lnet.ln_testprotocompat & 2) != 0) {
-                        hmv->magic = LNET_PROTO_MAGIC;
-                        the_lnet.ln_testprotocompat &= ~2;
-                }
-                LNET_UNLOCK();
-        }
-
-        hdr->src_nid        = cpu_to_le64 (hello->kshm_src_nid);
-        hdr->src_pid        = cpu_to_le32 (hello->kshm_src_pid);
-        hdr->type           = cpu_to_le32 (LNET_MSG_HELLO);
-        hdr->payload_length = cpu_to_le32 (hello->kshm_nips * sizeof(__u32));
-        hdr->msg.hello.type = cpu_to_le32 (hello->kshm_ctype);
-        hdr->msg.hello.incarnation = cpu_to_le64 (hello->kshm_src_incarnation);
-
-        rc = libcfs_sock_write(sock, hdr, sizeof(*hdr), lnet_acceptor_timeout());
-
-        if (rc != 0) {
-                CDEBUG (D_NETERROR, "Error %d sending HELLO hdr to %u.%u.%u.%u/%d\n",
-                        rc, HIPQUAD(conn->ksnc_ipaddr), conn->ksnc_port);
-                goto out;
-        }
-
-        if (hello->kshm_nips == 0)
-                goto out;
-
-        for (i = 0; i < hello->kshm_nips; i++) {
-                hello->kshm_ips[i] = __cpu_to_le32 (hello->kshm_ips[i]);
-        }
-
-        rc = libcfs_sock_write(sock, hello->kshm_ips,
-                               hello->kshm_nips * sizeof(__u32),
-                               lnet_acceptor_timeout());
-        if (rc != 0) {
-                CDEBUG (D_NETERROR, "Error %d sending HELLO payload (%d)"
-                        " to %u.%u.%u.%u/%d\n", rc, hello->kshm_nips,
-                        HIPQUAD(conn->ksnc_ipaddr), conn->ksnc_port);
-        }
-out:
-        LIBCFS_FREE(hdr, sizeof(*hdr));
-
-        return rc;
-}
-
-static int
-ksocknal_send_hello_v2 (ksock_conn_t *conn, ksock_hello_msg_t *hello)
-{
-        cfs_socket_t   *sock = conn->ksnc_sock;
-        int             rc;
-
-        hello->kshm_magic       = LNET_PROTO_MAGIC;
-        hello->kshm_version     = KSOCK_PROTO_V2;
-
-        if (the_lnet.ln_testprotocompat != 0) {
-                /* single-shot proto check */
-                LNET_LOCK();
-                if ((the_lnet.ln_testprotocompat & 1) != 0) {
-                        hello->kshm_version++;   /* just different! */
-                        the_lnet.ln_testprotocompat &= ~1;
-                }
-                LNET_UNLOCK();
-        }
-
-        rc = libcfs_sock_write(sock, hello, offsetof(ksock_hello_msg_t, kshm_ips),
-                               lnet_acceptor_timeout());
-
-        if (rc != 0) {
-                CDEBUG (D_NETERROR, "Error %d sending HELLO hdr to %u.%u.%u.%u/%d\n",
-                        rc, HIPQUAD(conn->ksnc_ipaddr), conn->ksnc_port);
-                return rc;
-        }
-
-        if (hello->kshm_nips == 0)
-                return 0;
-
-        rc = libcfs_sock_write(sock, hello->kshm_ips,
-                               hello->kshm_nips * sizeof(__u32),
-                               lnet_acceptor_timeout());
-        if (rc != 0) {
-                CDEBUG (D_NETERROR, "Error %d sending HELLO payload (%d)"
-                        " to %u.%u.%u.%u/%d\n", rc, hello->kshm_nips,
-                        HIPQUAD(conn->ksnc_ipaddr), conn->ksnc_port);
-        }
-
-        return rc;
-}
-
-static int
-ksocknal_recv_hello_v1(ksock_conn_t *conn, ksock_hello_msg_t *hello,int timeout)
-{
-        cfs_socket_t        *sock = conn->ksnc_sock;
-        lnet_hdr_t          *hdr;
-        int                  rc;
-        int                  i;
-
-        LIBCFS_ALLOC(hdr, sizeof(*hdr));
-        if (hdr == NULL) {
-                CERROR("Can't allocate lnet_hdr_t\n");
-                return -ENOMEM;
-        }
-
-        rc = libcfs_sock_read(sock, &hdr->src_nid,
-                              sizeof (*hdr) - offsetof (lnet_hdr_t, src_nid),
-                              timeout);
-        if (rc != 0) {
-                CERROR ("Error %d reading rest of HELLO hdr from %u.%u.%u.%u\n",
-                        rc, HIPQUAD(conn->ksnc_ipaddr));
-                LASSERT (rc < 0 && rc != -EALREADY);
-                goto out;
-        }
-
-        /* ...and check we got what we expected */
-        if (hdr->type != cpu_to_le32 (LNET_MSG_HELLO)) {
-                CERROR ("Expecting a HELLO hdr,"
-                        " but got type %d from %u.%u.%u.%u\n",
-                        le32_to_cpu (hdr->type),
-                        HIPQUAD(conn->ksnc_ipaddr));
-                rc = -EPROTO;
-                goto out;
-        }
-
-        hello->kshm_src_nid         = le64_to_cpu (hdr->src_nid);
-        hello->kshm_src_pid         = le32_to_cpu (hdr->src_pid);
-        hello->kshm_src_incarnation = le64_to_cpu (hdr->msg.hello.incarnation);
-        hello->kshm_ctype           = le32_to_cpu (hdr->msg.hello.type);
-        hello->kshm_nips            = le32_to_cpu (hdr->payload_length) /
-                                         sizeof (__u32);
-
-        if (hello->kshm_nips > LNET_MAX_INTERFACES) {
-                CERROR("Bad nips %d from ip %u.%u.%u.%u\n",
-                       hello->kshm_nips, HIPQUAD(conn->ksnc_ipaddr));
-                rc = -EPROTO;
-                goto out;
-        }
-
-        if (hello->kshm_nips == 0)
-                goto out;
-
-        rc = libcfs_sock_read(sock, hello->kshm_ips,
-                              hello->kshm_nips * sizeof(__u32), timeout);
-        if (rc != 0) {
-                CERROR ("Error %d reading IPs from ip %u.%u.%u.%u\n",
-                        rc, HIPQUAD(conn->ksnc_ipaddr));
-                LASSERT (rc < 0 && rc != -EALREADY);
-                goto out;
-        }
-
-        for (i = 0; i < hello->kshm_nips; i++) {
-                hello->kshm_ips[i] = __le32_to_cpu(hello->kshm_ips[i]);
-
-                if (hello->kshm_ips[i] == 0) {
-                        CERROR("Zero IP[%d] from ip %u.%u.%u.%u\n",
-                               i, HIPQUAD(conn->ksnc_ipaddr));
-                        rc = -EPROTO;
-                        break;
-                }
-        }
-out:
-        LIBCFS_FREE(hdr, sizeof(*hdr));
-
-        return rc;
-}
-
-static int
-ksocknal_recv_hello_v2 (ksock_conn_t *conn, ksock_hello_msg_t *hello, int timeout)
-{
-        cfs_socket_t      *sock = conn->ksnc_sock;
-        int                rc;
-        int                i;
-
-        if (hello->kshm_magic == LNET_PROTO_MAGIC)
-                conn->ksnc_flip = 0;
-        else
-                conn->ksnc_flip = 1;
-
-        rc = libcfs_sock_read(sock, &hello->kshm_src_nid,
-                              offsetof(ksock_hello_msg_t, kshm_ips) -
-                                       offsetof(ksock_hello_msg_t, kshm_src_nid),
-                              timeout);
-        if (rc != 0) {
-                CERROR ("Error %d reading HELLO from %u.%u.%u.%u\n",
-                        rc, HIPQUAD(conn->ksnc_ipaddr));
-                LASSERT (rc < 0 && rc != -EALREADY);
-                return rc;
-        }
-
-        if (conn->ksnc_flip) {
-                __swab32s(&hello->kshm_src_pid);
-                __swab64s(&hello->kshm_src_nid);
-                __swab32s(&hello->kshm_dst_pid);
-                __swab64s(&hello->kshm_dst_nid);
-                __swab64s(&hello->kshm_src_incarnation);
-                __swab64s(&hello->kshm_dst_incarnation);
-                __swab32s(&hello->kshm_ctype);
-                __swab32s(&hello->kshm_nips);
-        }
-
-        if (hello->kshm_nips > LNET_MAX_INTERFACES) {
-                CERROR("Bad nips %d from ip %u.%u.%u.%u\n",
-                       hello->kshm_nips, HIPQUAD(conn->ksnc_ipaddr));
-                return -EPROTO;
-        }
-
-        if (hello->kshm_nips == 0)
-                return 0;
-
-        rc = libcfs_sock_read(sock, hello->kshm_ips,
-                              hello->kshm_nips * sizeof(__u32), timeout);
-        if (rc != 0) {
-                CERROR ("Error %d reading IPs from ip %u.%u.%u.%u\n",
-                        rc, HIPQUAD(conn->ksnc_ipaddr));
-                LASSERT (rc < 0 && rc != -EALREADY);
-                return rc;
-        }
-
-        for (i = 0; i < hello->kshm_nips; i++) {
-                if (conn->ksnc_flip)
-                        __swab32s(&hello->kshm_ips[i]);
-
-                if (hello->kshm_ips[i] == 0) {
-                        CERROR("Zero IP[%d] from ip %u.%u.%u.%u\n",
-                               i, HIPQUAD(conn->ksnc_ipaddr));
-                        return -EPROTO;
-                }
-        }
-
-        return 0;
-}
-
-static void
-ksocknal_pack_msg_v1(ksock_tx_t *tx)
-{
-        /* V1.x has no KSOCK_MSG_NOOP */
-        LASSERT(tx->tx_msg.ksm_type != KSOCK_MSG_NOOP);
-        LASSERT(tx->tx_lnetmsg != NULL);
-
-        tx->tx_iov[0].iov_base = (void *)&tx->tx_lnetmsg->msg_hdr;
-        tx->tx_iov[0].iov_len  = sizeof(lnet_hdr_t);
-
-        tx->tx_resid = tx->tx_nob = tx->tx_lnetmsg->msg_len + sizeof(lnet_hdr_t);
-}
-
-static void
-ksocknal_pack_msg_v2(ksock_tx_t *tx)
-{
-        tx->tx_iov[0].iov_base = (void *)&tx->tx_msg;
-
-        if (tx->tx_lnetmsg != NULL) {
-                LASSERT(tx->tx_msg.ksm_type != KSOCK_MSG_NOOP);
-
-                tx->tx_msg.ksm_u.lnetmsg.ksnm_hdr = tx->tx_lnetmsg->msg_hdr;
-                tx->tx_iov[0].iov_len = offsetof(ksock_msg_t, ksm_u.lnetmsg.ksnm_payload);
-                tx->tx_resid = tx->tx_nob = offsetof(ksock_msg_t,  ksm_u.lnetmsg.ksnm_payload) +
-                                            tx->tx_lnetmsg->msg_len;
-        } else {
-                LASSERT(tx->tx_msg.ksm_type == KSOCK_MSG_NOOP);
-
-                tx->tx_iov[0].iov_len = offsetof(ksock_msg_t, ksm_u.lnetmsg.ksnm_hdr);
-                tx->tx_resid = tx->tx_nob = offsetof(ksock_msg_t,  ksm_u.lnetmsg.ksnm_hdr);
-        }
-        /* Don't checksum before start sending, because packet can be piggybacked with ACK */
-}
-
-static void
-ksocknal_unpack_msg_v1(ksock_msg_t *msg)
-{
-        msg->ksm_type           = KSOCK_MSG_LNET;
-        msg->ksm_csum           = 0;
-        msg->ksm_zc_req_cookie  = 0;
-        msg->ksm_zc_ack_cookie  = 0;
-}
-
-static void
-ksocknal_unpack_msg_v2(ksock_msg_t *msg)
-{
-        return;  /* Do nothing */
-}
-
-ksock_proto_t  ksocknal_protocol_v1x =
-{
-        KSOCK_PROTO_V1,
-        ksocknal_send_hello_v1,
-        ksocknal_recv_hello_v1,
-        ksocknal_pack_msg_v1,
-        ksocknal_unpack_msg_v1
-};
-
-ksock_proto_t  ksocknal_protocol_v2x =
-{
-        KSOCK_PROTO_V2,
-        ksocknal_send_hello_v2,
-        ksocknal_recv_hello_v2,
-        ksocknal_pack_msg_v2,
-        ksocknal_unpack_msg_v2
-};
-
 int
 ksocknal_send_hello (lnet_ni_t *ni, ksock_conn_t *conn,
                      lnet_nid_t peer_nid, ksock_hello_msg_t *hello)
@@ -2110,7 +1644,7 @@ ksocknal_send_hello (lnet_ni_t *ni, ksock_conn_t *conn,
         /* CAVEAT EMPTOR: this byte flips 'ipaddrs' */
         ksock_net_t         *net = (ksock_net_t *)ni->ni_data;
 
-        LASSERT (0 <= hello->kshm_nips && hello->kshm_nips <= LNET_MAX_INTERFACES);
+        LASSERT (hello->kshm_nips <= LNET_MAX_INTERFACES);
 
         /* rely on caller to hold a ref on socket so it wouldn't disappear */
         LASSERT (conn->ksnc_proto != NULL);
@@ -2198,9 +1732,11 @@ ksocknal_recv_hello (lnet_ni_t *ni, ksock_conn_t *conn,
         if (proto == NULL) {
                 if (!active) {
                         /* unknown protocol from peer, tell peer my protocol */
-                        conn->ksnc_proto = &ksocknal_protocol_v2x;
+                        conn->ksnc_proto = &ksocknal_protocol_v3x;
 #if SOCKNAL_VERSION_DEBUG
-                        if (*ksocknal_tunables.ksnd_protocol != 2)
+                        if (*ksocknal_tunables.ksnd_protocol == 2)
+                                conn->ksnc_proto = &ksocknal_protocol_v2x;
+                        else if (*ksocknal_tunables.ksnd_protocol == 1)
                                 conn->ksnc_proto = &ksocknal_protocol_v1x;
 #endif
                         hello->kshm_nips = 0;
@@ -2288,7 +1824,7 @@ ksocknal_recv_hello (lnet_ni_t *ni, ksock_conn_t *conn,
         return 0;
 }
 
-void
+int
 ksocknal_connect (ksock_route_t *route)
 {
         CFS_LIST_HEAD    (zombies);
@@ -2303,7 +1839,7 @@ ksocknal_connect (ksock_route_t *route)
         deadline = cfs_time_add(cfs_time_current(),
                                 cfs_time_seconds(*ksocknal_tunables.ksnd_timeout));
 
-        write_lock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_lock_bh (&ksocknal_data.ksnd_global_lock);
 
         LASSERT (route->ksnr_scheduled);
         LASSERT (!route->ksnr_connecting);
@@ -2343,7 +1879,7 @@ ksocknal_connect (ksock_route_t *route)
                         type = SOCKLND_CONN_BULK_OUT;
                 }
 
-                write_unlock_bh (&ksocknal_data.ksnd_global_lock);
+                cfs_write_unlock_bh (&ksocknal_data.ksnd_global_lock);
 
                 if (cfs_time_aftereq(cfs_time_current(), deadline)) {
                         rc = -ETIMEDOUT;
@@ -2374,7 +1910,7 @@ ksocknal_connect (ksock_route_t *route)
                         CDEBUG(D_NET, "peer %s: conn race, retry later.\n",
                                libcfs_nid2str(peer->ksnp_id.nid));
 
-                write_lock_bh (&ksocknal_data.ksnd_global_lock);
+                cfs_write_lock_bh (&ksocknal_data.ksnd_global_lock);
         }
 
         route->ksnr_scheduled = 0;
@@ -2383,14 +1919,27 @@ ksocknal_connect (ksock_route_t *route)
         if (retry_later) {
                 /* re-queue for attention; this frees me up to handle
                  * the peer's incoming connection request */
+
+                if (rc == EALREADY ||
+                    (rc == 0 && peer->ksnp_accepting > 0)) {
+                        /* We want to introduce a delay before next
+                         * attempt to connect if we lost conn race,
+                         * but the race is resolved quickly usually,
+                         * so min_reconnectms should be good heuristic */
+                        route->ksnr_retry_interval =
+                                cfs_time_seconds(*ksocknal_tunables.ksnd_min_reconnectms)/1000;
+                        route->ksnr_timeout = cfs_time_add(cfs_time_current(),
+                                                           route->ksnr_retry_interval);
+                }
+
                 ksocknal_launch_connection_locked(route);
         }
 
-        write_unlock_bh (&ksocknal_data.ksnd_global_lock);
-        return;
+        cfs_write_unlock_bh (&ksocknal_data.ksnd_global_lock);
+        return retry_later;
 
  failed:
-        write_lock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_lock_bh (&ksocknal_data.ksnd_global_lock);
 
         route->ksnr_scheduled = 0;
         route->ksnr_connecting = 0;
@@ -2408,116 +1957,167 @@ ksocknal_connect (ksock_route_t *route)
         route->ksnr_timeout = cfs_time_add(cfs_time_current(),
                                            route->ksnr_retry_interval);
 
-        if (!list_empty(&peer->ksnp_tx_queue) &&
+        if (!cfs_list_empty(&peer->ksnp_tx_queue) &&
             peer->ksnp_accepting == 0 &&
             ksocknal_find_connecting_route_locked(peer) == NULL) {
+                ksock_conn_t *conn;
+
                 /* ksnp_tx_queue is queued on a conn on successful
-                 * connection */
-                LASSERT (list_empty (&peer->ksnp_conns));
+                 * connection for V1.x and V2.x */
+                if (!cfs_list_empty (&peer->ksnp_conns)) {
+                        conn = cfs_list_entry(peer->ksnp_conns.next,
+                                              ksock_conn_t, ksnc_list);
+                        LASSERT (conn->ksnc_proto == &ksocknal_protocol_v3x);
+                }
 
                 /* take all the blocked packets while I've got the lock and
                  * complete below... */
-                list_add(&zombies, &peer->ksnp_tx_queue);
-                list_del_init(&peer->ksnp_tx_queue);
+                cfs_list_splice_init(&peer->ksnp_tx_queue, &zombies);
         }
 
 #if 0           /* irrelevent with only eager routes */
         if (!route->ksnr_deleted) {
                 /* make this route least-favourite for re-selection */
-                list_del(&route->ksnr_list);
-                list_add_tail(&route->ksnr_list, &peer->ksnp_routes);
+                cfs_list_del(&route->ksnr_list);
+                cfs_list_add_tail(&route->ksnr_list, &peer->ksnp_routes);
         }
 #endif
-        write_unlock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_unlock_bh (&ksocknal_data.ksnd_global_lock);
 
         ksocknal_peer_failed(peer);
         ksocknal_txlist_done(peer->ksnp_ni, &zombies, 1);
+        return 0;
 }
 
-static inline int
-ksocknal_connd_connect_route_locked(void)
+/* Go through connd_routes queue looking for a route that
+   we can process right now */
+static ksock_route_t *
+ksocknal_connd_get_route_locked(signed long *timeout_p)
 {
-        /* Only handle an outgoing connection request if there is someone left
-         * to handle incoming connections */
-        return !list_empty(&ksocknal_data.ksnd_connd_routes) &&
-                ((ksocknal_data.ksnd_connd_connecting + 1) <
-                 *ksocknal_tunables.ksnd_nconnds);
-}
+        ksock_route_t *route;
+        cfs_time_t     now;
 
-static inline int
-ksocknal_connd_ready(void)
-{
-        int            rc;
+        /* Only handle an outgoing connection request if there
+         * is someone left to handle incoming connections */
+        if ((ksocknal_data.ksnd_connd_connecting + 1) >=
+            *ksocknal_tunables.ksnd_nconnds)
+                return NULL;
+
+        now = cfs_time_current();
 
-        spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
+        /* connd_routes can contain both pending and ordinary routes */
+        cfs_list_for_each_entry (route, &ksocknal_data.ksnd_connd_routes,
+                                 ksnr_connd_list) {
 
-        rc = ksocknal_data.ksnd_shuttingdown ||
-             !list_empty(&ksocknal_data.ksnd_connd_connreqs) ||
-             ksocknal_connd_connect_route_locked();
+                if (route->ksnr_retry_interval == 0 ||
+                    cfs_time_aftereq(now, route->ksnr_timeout))
+                        return route;
 
-        spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+                if (*timeout_p == CFS_MAX_SCHEDULE_TIMEOUT ||
+                    (int)*timeout_p > (int)(route->ksnr_timeout - now))
+                        *timeout_p = (int)(route->ksnr_timeout - now);
+        }
 
-        return rc;
+        return NULL;
 }
 
 int
 ksocknal_connd (void *arg)
 {
-        long               id = (long)arg;
+        long               id = (long)(long_ptr_t)arg;
         char               name[16];
         ksock_connreq_t   *cr;
         ksock_route_t     *route;
+        cfs_waitlink_t     wait;
+        signed long        timeout;
+        int                nloops = 0;
+        int                cons_retry = 0;
+        int                dropped_lock;
 
         snprintf (name, sizeof (name), "socknal_cd%02ld", id);
         cfs_daemonize (name);
         cfs_block_allsigs ();
 
-        spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
+        cfs_waitlink_init (&wait);
+
+        cfs_spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
 
         while (!ksocknal_data.ksnd_shuttingdown) {
 
-                if (!list_empty(&ksocknal_data.ksnd_connd_connreqs)) {
+                dropped_lock = 0;
+
+                if (!cfs_list_empty(&ksocknal_data.ksnd_connd_connreqs)) {
                         /* Connection accepted by the listener */
-                        cr = list_entry(ksocknal_data.ksnd_connd_connreqs.next,
-                                        ksock_connreq_t, ksncr_list);
+                        cr = cfs_list_entry(ksocknal_data.ksnd_connd_connreqs. \
+                                            next, ksock_connreq_t, ksncr_list);
 
-                        list_del(&cr->ksncr_list);
-                        spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+                        cfs_list_del(&cr->ksncr_list);
+                        cfs_spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+                        dropped_lock = 1;
 
                         ksocknal_create_conn(cr->ksncr_ni, NULL,
                                              cr->ksncr_sock, SOCKLND_CONN_NONE);
                         lnet_ni_decref(cr->ksncr_ni);
                         LIBCFS_FREE(cr, sizeof(*cr));
 
-                        spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
+                        cfs_spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
                 }
 
-                if (ksocknal_connd_connect_route_locked()) {
-                        /* Connection request */
-                        route = list_entry (ksocknal_data.ksnd_connd_routes.next,
-                                            ksock_route_t, ksnr_connd_list);
+                /* Sleep till explicit wake_up if no pending routes present */
+                timeout = CFS_MAX_SCHEDULE_TIMEOUT;
 
-                        list_del (&route->ksnr_connd_list);
+                /* Connection request */
+                route = ksocknal_connd_get_route_locked(&timeout);
+
+                if (route != NULL) {
+                        cfs_list_del (&route->ksnr_connd_list);
                         ksocknal_data.ksnd_connd_connecting++;
-                        spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+                        cfs_spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+                        dropped_lock = 1;
+
+                        if (ksocknal_connect(route)) {
+                                /* consecutive retry */
+                                if (cons_retry++ > SOCKNAL_INSANITY_RECONN) {
+                                        CWARN("massive consecutive "
+                                              "re-connecting to %u.%u.%u.%u\n",
+                                              HIPQUAD(route->ksnr_ipaddr));
+                                        cons_retry = 0;
+                                }
+                        } else {
+                                cons_retry = 0;
+                        }
 
-                        ksocknal_connect (route);
                         ksocknal_route_decref(route);
 
-                        spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
+                        cfs_spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
                         ksocknal_data.ksnd_connd_connecting--;
                 }
 
-                spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+                if (dropped_lock) {
+                        if (++nloops < SOCKNAL_RESCHED)
+                                continue;
+                        cfs_spin_unlock_bh(&ksocknal_data.ksnd_connd_lock);
+                        nloops = 0;
+                        cfs_cond_resched();
+                        cfs_spin_lock_bh(&ksocknal_data.ksnd_connd_lock);
+                        continue;
+                }
+
+                /* Nothing to do for 'timeout'  */
+                cfs_set_current_state (CFS_TASK_INTERRUPTIBLE);
+                cfs_waitq_add_exclusive (&ksocknal_data.ksnd_connd_waitq,
+                                         &wait);
+                cfs_spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
 
-                wait_event_interruptible_exclusive(
-                        ksocknal_data.ksnd_connd_waitq,
-                        ksocknal_connd_ready());
+                nloops = 0;
+                cfs_waitq_timedwait (&wait, CFS_TASK_INTERRUPTIBLE, timeout);
 
-                spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
+                cfs_set_current_state (CFS_TASK_RUNNING);
+                cfs_waitq_del (&ksocknal_data.ksnd_connd_waitq, &wait);
+                cfs_spin_lock_bh (&ksocknal_data.ksnd_connd_lock);
         }
 
-        spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
+        cfs_spin_unlock_bh (&ksocknal_data.ksnd_connd_lock);
 
         ksocknal_thread_fini ();
         return (0);
@@ -2528,18 +2128,18 @@ ksocknal_find_timed_out_conn (ksock_peer_t *peer)
 {
         /* We're called with a shared lock on ksnd_global_lock */
         ksock_conn_t      *conn;
-        struct list_head  *ctmp;
+        cfs_list_t        *ctmp;
 
-        list_for_each (ctmp, &peer->ksnp_conns) {
+        cfs_list_for_each (ctmp, &peer->ksnp_conns) {
                 int     error;
-                conn = list_entry (ctmp, ksock_conn_t, ksnc_list);
+                conn = cfs_list_entry (ctmp, ksock_conn_t, ksnc_list);
 
                 /* Don't need the {get,put}connsock dance to deref ksnc_sock */
                 LASSERT (!conn->ksnc_closing);
 
                 /* SOCK_ERROR will reset error code of socket in
                  * some platform (like Darwin8.x) */
-                error = SOCK_ERROR(conn->ksnc_sock);
+                error = libcfs_sock_error(conn->ksnc_sock);
                 if (error != 0) {
                         ksocknal_conn_addref(conn);
 
@@ -2589,8 +2189,8 @@ ksocknal_find_timed_out_conn (ksock_peer_t *peer)
                         return (conn);
                 }
 
-                if ((!list_empty(&conn->ksnc_tx_queue) ||
-                     SOCK_WMEM_QUEUED(conn->ksnc_sock) != 0) &&
+                if ((!cfs_list_empty(&conn->ksnc_tx_queue) ||
+                     libcfs_sock_wmem_queued(conn->ksnc_sock) != 0) &&
                     cfs_time_aftereq(cfs_time_current(),
                                      conn->ksnc_tx_deadline)) {
                         /* Timed out messages queued for sending or
@@ -2614,31 +2214,92 @@ ksocknal_flush_stale_txs(ksock_peer_t *peer)
 {
         ksock_tx_t        *tx;
         CFS_LIST_HEAD      (stale_txs);
-        
-        write_lock_bh (&ksocknal_data.ksnd_global_lock);
 
-        while (!list_empty (&peer->ksnp_tx_queue)) {
-                tx = list_entry (peer->ksnp_tx_queue.next,
-                                 ksock_tx_t, tx_list);
+        cfs_write_lock_bh (&ksocknal_data.ksnd_global_lock);
+
+        while (!cfs_list_empty (&peer->ksnp_tx_queue)) {
+                tx = cfs_list_entry (peer->ksnp_tx_queue.next,
+                                     ksock_tx_t, tx_list);
 
                 if (!cfs_time_aftereq(cfs_time_current(),
                                       tx->tx_deadline))
                         break;
-                
-                list_del (&tx->tx_list);
-                list_add_tail (&tx->tx_list, &stale_txs);
+
+                cfs_list_del (&tx->tx_list);
+                cfs_list_add_tail (&tx->tx_list, &stale_txs);
         }
 
-        write_unlock_bh (&ksocknal_data.ksnd_global_lock);
+        cfs_write_unlock_bh (&ksocknal_data.ksnd_global_lock);
 
         ksocknal_txlist_done(peer->ksnp_ni, &stale_txs, 1);
 }
 
+int
+ksocknal_send_keepalive_locked(ksock_peer_t *peer)
+{
+        ksock_sched_t  *sched;
+        ksock_conn_t   *conn;
+        ksock_tx_t     *tx;
+
+        if (cfs_list_empty(&peer->ksnp_conns)) /* last_alive will be updated by create_conn */
+                return 0;
+
+        if (peer->ksnp_proto != &ksocknal_protocol_v3x)
+                return 0;
+
+        if (*ksocknal_tunables.ksnd_keepalive <= 0 ||
+            cfs_time_before(cfs_time_current(),
+                            cfs_time_add(peer->ksnp_last_alive,
+                                         cfs_time_seconds(*ksocknal_tunables.ksnd_keepalive))))
+                return 0;
+
+        if (cfs_time_before(cfs_time_current(),
+                            peer->ksnp_send_keepalive))
+                return 0;
+
+        /* retry 10 secs later, so we wouldn't put pressure
+         * on this peer if we failed to send keepalive this time */
+        peer->ksnp_send_keepalive = cfs_time_shift(10);
+
+        conn = ksocknal_find_conn_locked(peer, NULL, 1);
+        if (conn != NULL) {
+                sched = conn->ksnc_scheduler;
+
+                cfs_spin_lock_bh (&sched->kss_lock);
+                if (!cfs_list_empty(&conn->ksnc_tx_queue)) {
+                        cfs_spin_unlock_bh(&sched->kss_lock);
+                        /* there is an queued ACK, don't need keepalive */
+                        return 0;
+                }
+
+                cfs_spin_unlock_bh(&sched->kss_lock);
+        }
+
+        cfs_read_unlock(&ksocknal_data.ksnd_global_lock);
+
+        /* cookie = 1 is reserved for keepalive PING */
+        tx = ksocknal_alloc_tx_noop(1, 1);
+        if (tx == NULL) {
+                cfs_read_lock(&ksocknal_data.ksnd_global_lock);
+                return -ENOMEM;
+        }
+
+        if (ksocknal_launch_packet(peer->ksnp_ni, tx, peer->ksnp_id) == 0) {
+                cfs_read_lock(&ksocknal_data.ksnd_global_lock);
+                return 1;
+        }
+
+        ksocknal_free_tx(tx);
+        cfs_read_lock(&ksocknal_data.ksnd_global_lock);
+
+        return -EIO;
+}
+
+
 void
 ksocknal_check_peer_timeouts (int idx)
 {
-        struct list_head *peers = &ksocknal_data.ksnd_peers[idx];
-        struct list_head *ptmp;
+        cfs_list_t       *peers = &ksocknal_data.ksnd_peers[idx];
         ksock_peer_t     *peer;
         ksock_conn_t     *conn;
 
@@ -2646,14 +2307,18 @@ ksocknal_check_peer_timeouts (int idx)
         /* NB. We expect to have a look at all the peers and not find any
          * connections to time out, so we just use a shared lock while we
          * take a look... */
-        read_lock (&ksocknal_data.ksnd_global_lock);
+        cfs_read_lock (&ksocknal_data.ksnd_global_lock);
+
+        cfs_list_for_each_entry_typed(peer, peers, ksock_peer_t, ksnp_list) {
+                if (ksocknal_send_keepalive_locked(peer) != 0) {
+                        cfs_read_unlock (&ksocknal_data.ksnd_global_lock);
+                        goto again;
+                }
 
-        list_for_each (ptmp, peers) {
-                peer = list_entry (ptmp, ksock_peer_t, ksnp_list);
                 conn = ksocknal_find_timed_out_conn (peer);
 
                 if (conn != NULL) {
-                        read_unlock (&ksocknal_data.ksnd_global_lock);
+                        cfs_read_unlock (&ksocknal_data.ksnd_global_lock);
 
                         ksocknal_close_conn_and_siblings (conn, -ETIMEDOUT);
 
@@ -2666,16 +2331,17 @@ ksocknal_check_peer_timeouts (int idx)
 
                 /* we can't process stale txs right here because we're
                  * holding only shared lock */
-                if (!list_empty (&peer->ksnp_tx_queue)) {
-                        ksock_tx_t *tx = list_entry (peer->ksnp_tx_queue.next,
-                                                     ksock_tx_t, tx_list);
+                if (!cfs_list_empty (&peer->ksnp_tx_queue)) {
+                        ksock_tx_t *tx =
+                                cfs_list_entry (peer->ksnp_tx_queue.next,
+                                                ksock_tx_t, tx_list);
 
                         if (cfs_time_aftereq(cfs_time_current(),
                                              tx->tx_deadline)) {
 
                                 ksocknal_peer_addref(peer);
-                                read_unlock (&ksocknal_data.ksnd_global_lock);
-                                
+                                cfs_read_unlock (&ksocknal_data.ksnd_global_lock);
+
                                 ksocknal_flush_stale_txs(peer);
 
                                 ksocknal_peer_decref(peer);
@@ -2685,11 +2351,12 @@ ksocknal_check_peer_timeouts (int idx)
         }
 
         /* print out warnings about stale ZC_REQs */
-        list_for_each_entry(peer, peers, ksnp_list) {
+        cfs_list_for_each_entry_typed(peer, peers, ksock_peer_t, ksnp_list) {
                 ksock_tx_t *tx;
                 int         n = 0;
-                
-                list_for_each_entry(tx, &peer->ksnp_zc_req_list, tx_zc_list) {
+
+                cfs_list_for_each_entry_typed(tx, &peer->ksnp_zc_req_list,
+                                              ksock_tx_t, tx_zc_list) {
                         if (!cfs_time_aftereq(cfs_time_current(),
                                               tx->tx_deadline))
                                 break;
@@ -2697,8 +2364,8 @@ ksocknal_check_peer_timeouts (int idx)
                 }
 
                 if (n != 0) {
-                        tx = list_entry (peer->ksnp_zc_req_list.next,
-                                         ksock_tx_t, tx_zc_list);
+                        tx = cfs_list_entry (peer->ksnp_zc_req_list.next,
+                                             ksock_tx_t, tx_zc_list);
                         CWARN("Stale ZC_REQs for peer %s detected: %d; the "
                               "oldest (%p) timed out %ld secs ago\n",
                               libcfs_nid2str(peer->ksnp_id.nid), n, tx,
@@ -2706,8 +2373,8 @@ ksocknal_check_peer_timeouts (int idx)
                                                tx->tx_deadline));
                 }
         }
-        
-        read_unlock (&ksocknal_data.ksnd_global_lock);
+
+        cfs_read_unlock (&ksocknal_data.ksnd_global_lock);
 }
 
 int
@@ -2716,7 +2383,7 @@ ksocknal_reaper (void *arg)
         cfs_waitlink_t     wait;
         ksock_conn_t      *conn;
         ksock_sched_t     *sched;
-        struct list_head   enomem_conns;
+        cfs_list_t         enomem_conns;
         int                nenomem_conns;
         cfs_duration_t     timeout;
         int                i;
@@ -2729,61 +2396,64 @@ ksocknal_reaper (void *arg)
         CFS_INIT_LIST_HEAD(&enomem_conns);
         cfs_waitlink_init (&wait);
 
-        spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
+        cfs_spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
 
         while (!ksocknal_data.ksnd_shuttingdown) {
 
-                if (!list_empty (&ksocknal_data.ksnd_deathrow_conns)) {
-                        conn = list_entry (ksocknal_data.ksnd_deathrow_conns.next,
-                                           ksock_conn_t, ksnc_list);
-                        list_del (&conn->ksnc_list);
+                if (!cfs_list_empty (&ksocknal_data.ksnd_deathrow_conns)) {
+                        conn = cfs_list_entry (ksocknal_data. \
+                                               ksnd_deathrow_conns.next,
+                                               ksock_conn_t, ksnc_list);
+                        cfs_list_del (&conn->ksnc_list);
 
-                        spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
+                        cfs_spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
 
                         ksocknal_terminate_conn (conn);
                         ksocknal_conn_decref(conn);
 
-                        spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
+                        cfs_spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
                         continue;
                 }
 
-                if (!list_empty (&ksocknal_data.ksnd_zombie_conns)) {
-                        conn = list_entry (ksocknal_data.ksnd_zombie_conns.next,
-                                           ksock_conn_t, ksnc_list);
-                        list_del (&conn->ksnc_list);
+                if (!cfs_list_empty (&ksocknal_data.ksnd_zombie_conns)) {
+                        conn = cfs_list_entry (ksocknal_data.ksnd_zombie_conns.\
+                                               next, ksock_conn_t, ksnc_list);
+                        cfs_list_del (&conn->ksnc_list);
 
-                        spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
+                        cfs_spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
 
                         ksocknal_destroy_conn (conn);
 
-                        spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
+                        cfs_spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
                         continue;
                 }
 
-                if (!list_empty (&ksocknal_data.ksnd_enomem_conns)) {
-                        list_add(&enomem_conns, &ksocknal_data.ksnd_enomem_conns);
-                        list_del_init(&ksocknal_data.ksnd_enomem_conns);
+                if (!cfs_list_empty (&ksocknal_data.ksnd_enomem_conns)) {
+                        cfs_list_add(&enomem_conns,
+                                     &ksocknal_data.ksnd_enomem_conns);
+                        cfs_list_del_init(&ksocknal_data.ksnd_enomem_conns);
                 }
 
-                spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
+                cfs_spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
 
                 /* reschedule all the connections that stalled with ENOMEM... */
                 nenomem_conns = 0;
-                while (!list_empty (&enomem_conns)) {
-                        conn = list_entry (enomem_conns.next,
-                                           ksock_conn_t, ksnc_tx_list);
-                        list_del (&conn->ksnc_tx_list);
+                while (!cfs_list_empty (&enomem_conns)) {
+                        conn = cfs_list_entry (enomem_conns.next,
+                                               ksock_conn_t, ksnc_tx_list);
+                        cfs_list_del (&conn->ksnc_tx_list);
 
                         sched = conn->ksnc_scheduler;
 
-                        spin_lock_bh (&sched->kss_lock);
+                        cfs_spin_lock_bh (&sched->kss_lock);
 
                         LASSERT (conn->ksnc_tx_scheduled);
                         conn->ksnc_tx_ready = 1;
-                        list_add_tail(&conn->ksnc_tx_list, &sched->kss_tx_conns);
+                        cfs_list_add_tail(&conn->ksnc_tx_list,
+                                          &sched->kss_tx_conns);
                         cfs_waitq_signal (&sched->kss_waitq);
 
-                        spin_unlock_bh (&sched->kss_lock);
+                        cfs_spin_unlock_bh (&sched->kss_lock);
                         nenomem_conns++;
                 }
 
@@ -2825,21 +2495,22 @@ ksocknal_reaper (void *arg)
                 ksocknal_data.ksnd_reaper_waketime =
                         cfs_time_add(cfs_time_current(), timeout);
 
-                set_current_state (TASK_INTERRUPTIBLE);
+                cfs_set_current_state (CFS_TASK_INTERRUPTIBLE);
                 cfs_waitq_add (&ksocknal_data.ksnd_reaper_waitq, &wait);
 
                 if (!ksocknal_data.ksnd_shuttingdown &&
-                    list_empty (&ksocknal_data.ksnd_deathrow_conns) &&
-                    list_empty (&ksocknal_data.ksnd_zombie_conns))
-                        cfs_waitq_timedwait (&wait, CFS_TASK_INTERRUPTIBLE, timeout);
+                    cfs_list_empty (&ksocknal_data.ksnd_deathrow_conns) &&
+                    cfs_list_empty (&ksocknal_data.ksnd_zombie_conns))
+                        cfs_waitq_timedwait (&wait, CFS_TASK_INTERRUPTIBLE,
+                                             timeout);
 
-                set_current_state (TASK_RUNNING);
+                cfs_set_current_state (CFS_TASK_RUNNING);
                 cfs_waitq_del (&ksocknal_data.ksnd_reaper_waitq, &wait);
 
-                spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
+                cfs_spin_lock_bh (&ksocknal_data.ksnd_reaper_lock);
         }
 
-        spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
+        cfs_spin_unlock_bh (&ksocknal_data.ksnd_reaper_lock);
 
         ksocknal_thread_fini ();
         return (0);