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 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *
  * Copyright (C) 2004 Oracle.  All rights reserved.
  *
  * ----
  *
  * Callers for this were originally written against a very simple synchronus
  * API.  This implementation reflects those simple callers.  Some day I'm sure
  * we'll need to move to a more robust posting/callback mechanism.
  *
  * Transmit calls pass in kernel virtual addresses and block copying this into
  * the socket's tx buffers via a usual blocking sendmsg.  They'll block waiting
  * for a failed socket to timeout.  TX callers can also pass in a poniter to an
  * 'int' which gets filled with an errno off the wire in response to the
  * message they send.
  *
  * Handlers for unsolicited messages are registered.  Each socket has a page
  * that incoming data is copied into.  First the header, then the data.
  * Handlers are called from only one thread with a reference to this per-socket
  * page.  This page is destroyed after the handler call, so it can't be
  * referenced beyond the call.  Handlers may block but are discouraged from
  * doing so.
  *
  * Any framing errors (bad magic, large payload lengths) close a connection.
  *
  * Our sock_container holds the state we associate with a socket.  It's current
  * framing state is held there as well as the refcounting we do around when it
  * is safe to tear down the socket.  The socket is only finally torn down from
  * the container when the container loses all of its references -- so as long
  * as you hold a ref on the container you can trust that the socket is valid
  * for use with kernel socket APIs.
  *
  * Connections are initiated between a pair of nodes when the node with the
  * higher node number gets a heartbeat callback which indicates that the lower
  * numbered node has started heartbeating.  The lower numbered node is passive
  * and only accepts the connection if the higher numbered node is heartbeating.
  */
 
 #include <linux/kernel.h>
 #include <linux/sched/mm.h>
 #include <linux/jiffies.h>
 #include <linux/slab.h>
 #include <linux/idr.h>
 #include <linux/kref.h>
 #include <linux/net.h>
 #include <linux/export.h>
 #include <net/tcp.h>
 
 #include <linux/uaccess.h>
 
 #include "heartbeat.h"
 #include "tcp.h"
 #include "nodemanager.h"
 #define MLOG_MASK_PREFIX ML_TCP
 #include "masklog.h"
 #include "quorum.h"
 
 #include "tcp_internal.h"
 
 #define SC_NODEF_FMT "node %s (num %u) at %pI4:%u"
 #define SC_NODEF_ARGS(sc) sc->sc_node->nd_name, sc->sc_node->nd_num,    \
               &sc->sc_node->nd_ipv4_address,        \
               ntohs(sc->sc_node->nd_ipv4_port)
 
 /*
  * In the following two log macros, the whitespace after the ',' just
  * before ##args is intentional. Otherwise, gcc 2.95 will eat the
  * previous token if args expands to nothing.
  */
 #define msglog(hdr, fmt, args...) do {                  \
     typeof(hdr) __hdr = (hdr);                  \
     mlog(ML_MSG, "[mag %u len %u typ %u stat %d sys_stat %d "   \
          "key %08x num %u] " fmt,                   \
          be16_to_cpu(__hdr->magic), be16_to_cpu(__hdr->data_len),   \
          be16_to_cpu(__hdr->msg_type), be32_to_cpu(__hdr->status),  \
          be32_to_cpu(__hdr->sys_status), be32_to_cpu(__hdr->key),   \
          be32_to_cpu(__hdr->msg_num) ,  ##args);            \
 } while (0)
 
 #define sclog(sc, fmt, args...) do {                    \
     typeof(sc) __sc = (sc);                     \
     mlog(ML_SOCKET, "[sc %p refs %d sock %p node %u page %p "   \
          "pg_off %zu] " fmt, __sc,                  \
          kref_read(&__sc->sc_kref), __sc->sc_sock,  \
         __sc->sc_node->nd_num, __sc->sc_page, __sc->sc_page_off ,   \
         ##args);                            \
 } while (0)
 
 static DEFINE_RWLOCK(o2net_handler_lock);
 static struct rb_root o2net_handler_tree = RB_ROOT;
 
 static struct o2net_node o2net_nodes[O2NM_MAX_NODES];
 
 /* XXX someday we'll need better accounting */
 static struct socket *o2net_listen_sock;
 
 /*
  * listen work is only queued by the listening socket callbacks on the
  * o2net_wq.  teardown detaches the callbacks before destroying the workqueue.
  * quorum work is queued as sock containers are shutdown.. stop_listening
  * tears down all the node's sock containers, preventing future shutdowns
  * and queued quroum work, before canceling delayed quorum work and
  * destroying the work queue.
  */
 static struct workqueue_struct *o2net_wq;
 static struct work_struct o2net_listen_work;
 
 static struct o2hb_callback_func o2net_hb_up, o2net_hb_down;
 #define O2NET_HB_PRI 0x1
 
 static struct o2net_handshake *o2net_hand;
 static struct o2net_msg *o2net_keep_req, *o2net_keep_resp;
 
 static int o2net_sys_err_translations[O2NET_ERR_MAX] =
         {[O2NET_ERR_NONE]   = 0,
          [O2NET_ERR_NO_HNDLR]   = -ENOPROTOOPT,
          [O2NET_ERR_OVERFLOW]   = -EOVERFLOW,
          [O2NET_ERR_DIED]   = -EHOSTDOWN,};
 
 /* can't quite avoid *all* internal declarations :/ */
 static void o2net_sc_connect_completed(struct work_struct *work);
 static void o2net_rx_until_empty(struct work_struct *work);
 static void o2net_shutdown_sc(struct work_struct *work);
 static void o2net_listen_data_ready(struct sock *sk);
 static void o2net_sc_send_keep_req(struct work_struct *work);
 static void o2net_idle_timer(struct timer_list *t);
 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc);
 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc);
 
 #ifdef CONFIG_DEBUG_FS
 static void o2net_init_nst(struct o2net_send_tracking *nst, u32 msgtype,
                u32 msgkey, struct task_struct *task, u8 node)
 {
     INIT_LIST_HEAD(&nst->st_net_debug_item);
     nst->st_task = task;
     nst->st_msg_type = msgtype;
     nst->st_msg_key = msgkey;
     nst->st_node = node;
 }
 
 static inline void o2net_set_nst_sock_time(struct o2net_send_tracking *nst)
 {
     nst->st_sock_time = ktime_get();
 }
 
 static inline void o2net_set_nst_send_time(struct o2net_send_tracking *nst)
 {
     nst->st_send_time = ktime_get();
 }
 
 static inline void o2net_set_nst_status_time(struct o2net_send_tracking *nst)
 {
     nst->st_status_time = ktime_get();
 }
 
 static inline void o2net_set_nst_sock_container(struct o2net_send_tracking *nst,
                         struct o2net_sock_container *sc)
 {
     nst->st_sc = sc;
 }
 
 static inline void o2net_set_nst_msg_id(struct o2net_send_tracking *nst,
                     u32 msg_id)
 {
     nst->st_id = msg_id;
 }
 
 static inline void o2net_set_sock_timer(struct o2net_sock_container *sc)
 {
     sc->sc_tv_timer = ktime_get();
 }
 
 static inline void o2net_set_data_ready_time(struct o2net_sock_container *sc)
 {
     sc->sc_tv_data_ready = ktime_get();
 }
 
 static inline void o2net_set_advance_start_time(struct o2net_sock_container *sc)
 {
     sc->sc_tv_advance_start = ktime_get();
 }
 
 static inline void o2net_set_advance_stop_time(struct o2net_sock_container *sc)
 {
     sc->sc_tv_advance_stop = ktime_get();
 }
 
 static inline void o2net_set_func_start_time(struct o2net_sock_container *sc)
 {
     sc->sc_tv_func_start = ktime_get();
 }
 
 static inline void o2net_set_func_stop_time(struct o2net_sock_container *sc)
 {
     sc->sc_tv_func_stop = ktime_get();
 }
 
 #else  /* CONFIG_DEBUG_FS */
 # define o2net_init_nst(a, b, c, d, e)
 # define o2net_set_nst_sock_time(a)
 # define o2net_set_nst_send_time(a)
 # define o2net_set_nst_status_time(a)
 # define o2net_set_nst_sock_container(a, b)
 # define o2net_set_nst_msg_id(a, b)
 # define o2net_set_sock_timer(a)
 # define o2net_set_data_ready_time(a)
 # define o2net_set_advance_start_time(a)
 # define o2net_set_advance_stop_time(a)
 # define o2net_set_func_start_time(a)
 # define o2net_set_func_stop_time(a)
 #endif /* CONFIG_DEBUG_FS */
 
 #ifdef CONFIG_OCFS2_FS_STATS
 static ktime_t o2net_get_func_run_time(struct o2net_sock_container *sc)
 {
     return ktime_sub(sc->sc_tv_func_stop, sc->sc_tv_func_start);
 }
 
 static void o2net_update_send_stats(struct o2net_send_tracking *nst,
                     struct o2net_sock_container *sc)
 {
     sc->sc_tv_status_total = ktime_add(sc->sc_tv_status_total,
                        ktime_sub(ktime_get(),
                              nst->st_status_time));
     sc->sc_tv_send_total = ktime_add(sc->sc_tv_send_total,
                      ktime_sub(nst->st_status_time,
                            nst->st_send_time));
     sc->sc_tv_acquiry_total = ktime_add(sc->sc_tv_acquiry_total,
                         ktime_sub(nst->st_send_time,
                               nst->st_sock_time));
     sc->sc_send_count++;
 }
 
 static void o2net_update_recv_stats(struct o2net_sock_container *sc)
 {
     sc->sc_tv_process_total = ktime_add(sc->sc_tv_process_total,
                         o2net_get_func_run_time(sc));
     sc->sc_recv_count++;
 }
 
 #else
 
 # define o2net_update_send_stats(a, b)
 
 # define o2net_update_recv_stats(sc)
 
 #endif /* CONFIG_OCFS2_FS_STATS */
 
 static inline unsigned int o2net_reconnect_delay(void)
 {
     return o2nm_single_cluster->cl_reconnect_delay_ms;
 }
 
 static inline unsigned int o2net_keepalive_delay(void)
 {
     return o2nm_single_cluster->cl_keepalive_delay_ms;
 }
 
 static inline unsigned int o2net_idle_timeout(void)
 {
     return o2nm_single_cluster->cl_idle_timeout_ms;
 }
 
 static inline int o2net_sys_err_to_errno(enum o2net_system_error err)
 {
     int trans;
     BUG_ON(err >= O2NET_ERR_MAX);
     trans = o2net_sys_err_translations[err];
 
     /* Just in case we mess up the translation table above */
     BUG_ON(err != O2NET_ERR_NONE && trans == 0);
     return trans;
 }
 
 static struct o2net_node * o2net_nn_from_num(u8 node_num)
 {
     BUG_ON(node_num >= ARRAY_SIZE(o2net_nodes));
     return &o2net_nodes[node_num];
 }
 
 static u8 o2net_num_from_nn(struct o2net_node *nn)
 {
     BUG_ON(nn == NULL);
     return nn - o2net_nodes;
 }
 
 /* ------------------------------------------------------------ */
 
 static int o2net_prep_nsw(struct o2net_node *nn, struct o2net_status_wait *nsw)
 {
     int ret;
 
     spin_lock(&nn->nn_lock);
     ret = idr_alloc(&nn->nn_status_idr, nsw, 0, 0, GFP_ATOMIC);
     if (ret >= 0) {
         nsw->ns_id = ret;
         list_add_tail(&nsw->ns_node_item, &nn->nn_status_list);
     }
     spin_unlock(&nn->nn_lock);
     if (ret < 0)
         return ret;
 
     init_waitqueue_head(&nsw->ns_wq);
     nsw->ns_sys_status = O2NET_ERR_NONE;
     nsw->ns_status = 0;
     return 0;
 }
 
 static void o2net_complete_nsw_locked(struct o2net_node *nn,
                       struct o2net_status_wait *nsw,
                       enum o2net_system_error sys_status,
                       s32 status)
 {
     assert_spin_locked(&nn->nn_lock);
 
     if (!list_empty(&nsw->ns_node_item)) {
         list_del_init(&nsw->ns_node_item);
         nsw->ns_sys_status = sys_status;
         nsw->ns_status = status;
         idr_remove(&nn->nn_status_idr, nsw->ns_id);
         wake_up(&nsw->ns_wq);
     }
 }
 
 static void o2net_complete_nsw(struct o2net_node *nn,
                    struct o2net_status_wait *nsw,
                    u64 id, enum o2net_system_error sys_status,
                    s32 status)
 {
     spin_lock(&nn->nn_lock);
     if (nsw == NULL) {
         if (id > INT_MAX)
             goto out;
 
         nsw = idr_find(&nn->nn_status_idr, id);
         if (nsw == NULL)
             goto out;
     }
 
     o2net_complete_nsw_locked(nn, nsw, sys_status, status);
 
 out:
     spin_unlock(&nn->nn_lock);
     return;
 }
 
 static void o2net_complete_nodes_nsw(struct o2net_node *nn)
 {
     struct o2net_status_wait *nsw, *tmp;
     unsigned int num_kills = 0;
 
     assert_spin_locked(&nn->nn_lock);
 
     list_for_each_entry_safe(nsw, tmp, &nn->nn_status_list, ns_node_item) {
         o2net_complete_nsw_locked(nn, nsw, O2NET_ERR_DIED, 0);
         num_kills++;
     }
 
     mlog(0, "completed %d messages for node %u\n", num_kills,
          o2net_num_from_nn(nn));
 }
 
 static int o2net_nsw_completed(struct o2net_node *nn,
                    struct o2net_status_wait *nsw)
 {
     int completed;
     spin_lock(&nn->nn_lock);
     completed = list_empty(&nsw->ns_node_item);
     spin_unlock(&nn->nn_lock);
     return completed;
 }
 
 /* ------------------------------------------------------------ */
 
 static void sc_kref_release(struct kref *kref)
 {
     struct o2net_sock_container *sc = container_of(kref,
                     struct o2net_sock_container, sc_kref);
     BUG_ON(timer_pending(&sc->sc_idle_timeout));
 
     sclog(sc, "releasing\n");
 
     if (sc->sc_sock) {
         sock_release(sc->sc_sock);
         sc->sc_sock = NULL;
     }
 
     o2nm_undepend_item(&sc->sc_node->nd_item);
     o2nm_node_put(sc->sc_node);
     sc->sc_node = NULL;
 
     o2net_debug_del_sc(sc);
 
     if (sc->sc_page)
         __free_page(sc->sc_page);
     kfree(sc);
 }
 
 static void sc_put(struct o2net_sock_container *sc)
 {
     sclog(sc, "put\n");
     kref_put(&sc->sc_kref, sc_kref_release);
 }
 static void sc_get(struct o2net_sock_container *sc)
 {
     sclog(sc, "get\n");
     kref_get(&sc->sc_kref);
 }
 static struct o2net_sock_container *sc_alloc(struct o2nm_node *node)
 {
     struct o2net_sock_container *sc, *ret = NULL;
     struct page *page = NULL;
     int status = 0;
 
     page = alloc_page(GFP_NOFS);
     sc = kzalloc(sizeof(*sc), GFP_NOFS);
     if (sc == NULL || page == NULL)
         goto out;
 
     kref_init(&sc->sc_kref);
     o2nm_node_get(node);
     sc->sc_node = node;
 
     /* pin the node item of the remote node */
     status = o2nm_depend_item(&node->nd_item);
     if (status) {
         mlog_errno(status);
         o2nm_node_put(node);
         goto out;
     }
     INIT_WORK(&sc->sc_connect_work, o2net_sc_connect_completed);
     INIT_WORK(&sc->sc_rx_work, o2net_rx_until_empty);
     INIT_WORK(&sc->sc_shutdown_work, o2net_shutdown_sc);
     INIT_DELAYED_WORK(&sc->sc_keepalive_work, o2net_sc_send_keep_req);
 
     timer_setup(&sc->sc_idle_timeout, o2net_idle_timer, 0);
 
     sclog(sc, "alloced\n");
 
     ret = sc;
     sc->sc_page = page;
     o2net_debug_add_sc(sc);
     sc = NULL;
     page = NULL;
 
 out:
     if (page)
         __free_page(page);
     kfree(sc);
 
     return ret;
 }
 
 /* ------------------------------------------------------------ */
 
 static void o2net_sc_queue_work(struct o2net_sock_container *sc,
                 struct work_struct *work)
 {
     sc_get(sc);
     if (!queue_work(o2net_wq, work))
         sc_put(sc);
 }
 static void o2net_sc_queue_delayed_work(struct o2net_sock_container *sc,
                     struct delayed_work *work,
                     int delay)
 {
     sc_get(sc);
     if (!queue_delayed_work(o2net_wq, work, delay))
         sc_put(sc);
 }
 static void o2net_sc_cancel_delayed_work(struct o2net_sock_container *sc,
                      struct delayed_work *work)
 {
     if (cancel_delayed_work(work))
         sc_put(sc);
 }
 
 static atomic_t o2net_connected_peers = ATOMIC_INIT(0);
 
 int o2net_num_connected_peers(void)
 {
     return atomic_read(&o2net_connected_peers);
 }
 
 static void o2net_set_nn_state(struct o2net_node *nn,
                    struct o2net_sock_container *sc,
                    unsigned valid, int err)
 {
     int was_valid = nn->nn_sc_valid;
     int was_err = nn->nn_persistent_error;
     struct o2net_sock_container *old_sc = nn->nn_sc;
 
     assert_spin_locked(&nn->nn_lock);
 
     if (old_sc && !sc)
         atomic_dec(&o2net_connected_peers);
     else if (!old_sc && sc)
         atomic_inc(&o2net_connected_peers);
 
     /* the node num comparison and single connect/accept path should stop
      * an non-null sc from being overwritten with another */
     BUG_ON(sc && nn->nn_sc && nn->nn_sc != sc);
     mlog_bug_on_msg(err && valid, "err %d valid %u\n", err, valid);
     mlog_bug_on_msg(valid && !sc, "valid %u sc %p\n", valid, sc);
 
     if (was_valid && !valid && err == 0)
         err = -ENOTCONN;
 
     mlog(ML_CONN, "node %u sc: %p -> %p, valid %u -> %u, err %d -> %d\n",
          o2net_num_from_nn(nn), nn->nn_sc, sc, nn->nn_sc_valid, valid,
          nn->nn_persistent_error, err);
 
     nn->nn_sc = sc;
     nn->nn_sc_valid = valid ? 1 : 0;
     nn->nn_persistent_error = err;
 
     /* mirrors o2net_tx_can_proceed() */
     if (nn->nn_persistent_error || nn->nn_sc_valid)
         wake_up(&nn->nn_sc_wq);
 
     if (was_valid && !was_err && nn->nn_persistent_error) {
         o2quo_conn_err(o2net_num_from_nn(nn));
         queue_delayed_work(o2net_wq, &nn->nn_still_up,
                    msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
     }
 
     if (was_valid && !valid) {
         if (old_sc)
             printk(KERN_NOTICE "o2net: No longer connected to "
                 SC_NODEF_FMT "\n", SC_NODEF_ARGS(old_sc));
         o2net_complete_nodes_nsw(nn);
     }
 
     if (!was_valid && valid) {
         o2quo_conn_up(o2net_num_from_nn(nn));
         cancel_delayed_work(&nn->nn_connect_expired);
         printk(KERN_NOTICE "o2net: %s " SC_NODEF_FMT "\n",
                o2nm_this_node() > sc->sc_node->nd_num ?
                "Connected to" : "Accepted connection from",
                SC_NODEF_ARGS(sc));
     }
 
     /* trigger the connecting worker func as long as we're not valid,
      * it will back off if it shouldn't connect.  This can be called
      * from node config teardown and so needs to be careful about
      * the work queue actually being up. */
     if (!valid && o2net_wq) {
         unsigned long delay;
         /* delay if we're within a RECONNECT_DELAY of the
          * last attempt */
         delay = (nn->nn_last_connect_attempt +
              msecs_to_jiffies(o2net_reconnect_delay()))
             - jiffies;
         if (delay > msecs_to_jiffies(o2net_reconnect_delay()))
             delay = 0;
         mlog(ML_CONN, "queueing conn attempt in %lu jiffies\n", delay);
         queue_delayed_work(o2net_wq, &nn->nn_connect_work, delay);
 
         /*
          * Delay the expired work after idle timeout.
          *
          * We might have lots of failed connection attempts that run
          * through here but we only cancel the connect_expired work when
          * a connection attempt succeeds.  So only the first enqueue of
          * the connect_expired work will do anything.  The rest will see
          * that it's already queued and do nothing.
          */
         delay += msecs_to_jiffies(o2net_idle_timeout());
         queue_delayed_work(o2net_wq, &nn->nn_connect_expired, delay);
     }
 
     /* keep track of the nn's sc ref for the caller */
     if ((old_sc == NULL) && sc)
         sc_get(sc);
     if (old_sc && (old_sc != sc)) {
         o2net_sc_queue_work(old_sc, &old_sc->sc_shutdown_work);
         sc_put(old_sc);
     }
 }
 
 /* see o2net_register_callbacks() */
 static void o2net_data_ready(struct sock *sk)
 {
     void (*ready)(struct sock *sk);
     struct o2net_sock_container *sc;
 
     read_lock_bh(&sk->sk_callback_lock);
     sc = sk->sk_user_data;
     if (sc) {
         sclog(sc, "data_ready hit\n");
         o2net_set_data_ready_time(sc);
         o2net_sc_queue_work(sc, &sc->sc_rx_work);
         ready = sc->sc_data_ready;
     } else {
         ready = sk->sk_data_ready;
     }
     read_unlock_bh(&sk->sk_callback_lock);
 
     ready(sk);
 }
 
 /* see o2net_register_callbacks() */
 static void o2net_state_change(struct sock *sk)
 {
     void (*state_change)(struct sock *sk);
     struct o2net_sock_container *sc;
 
     read_lock_bh(&sk->sk_callback_lock);
     sc = sk->sk_user_data;
     if (sc == NULL) {
         state_change = sk->sk_state_change;
         goto out;
     }
 
     sclog(sc, "state_change to %d\n", sk->sk_state);
 
     state_change = sc->sc_state_change;
 
     switch(sk->sk_state) {
     /* ignore connecting sockets as they make progress */
     case TCP_SYN_SENT:
     case TCP_SYN_RECV:
         break;
     case TCP_ESTABLISHED:
         o2net_sc_queue_work(sc, &sc->sc_connect_work);
         break;
     default:
         printk(KERN_INFO "o2net: Connection to " SC_NODEF_FMT
             " shutdown, state %d\n",
             SC_NODEF_ARGS(sc), sk->sk_state);
         o2net_sc_queue_work(sc, &sc->sc_shutdown_work);
         break;
     }
 out:
     read_unlock_bh(&sk->sk_callback_lock);
     state_change(sk);
 }
 
 /*
  * we register callbacks so we can queue work on events before calling
  * the original callbacks.  our callbacks our careful to test user_data
  * to discover when they've reaced with o2net_unregister_callbacks().
  */
 static void o2net_register_callbacks(struct sock *sk,
                      struct o2net_sock_container *sc)
 {
     write_lock_bh(&sk->sk_callback_lock);
 
     /* accepted sockets inherit the old listen socket data ready */
     if (sk->sk_data_ready == o2net_listen_data_ready) {
         sk->sk_data_ready = sk->sk_user_data;
         sk->sk_user_data = NULL;
     }
 
     BUG_ON(sk->sk_user_data != NULL);
     sk->sk_user_data = sc;
     sc_get(sc);
 
     sc->sc_data_ready = sk->sk_data_ready;
     sc->sc_state_change = sk->sk_state_change;
     sk->sk_data_ready = o2net_data_ready;
     sk->sk_state_change = o2net_state_change;
 
     mutex_init(&sc->sc_send_lock);
 
     write_unlock_bh(&sk->sk_callback_lock);
 }
 
 static int o2net_unregister_callbacks(struct sock *sk,
                        struct o2net_sock_container *sc)
 {
     int ret = 0;
 
     write_lock_bh(&sk->sk_callback_lock);
     if (sk->sk_user_data == sc) {
         ret = 1;
         sk->sk_user_data = NULL;
         sk->sk_data_ready = sc->sc_data_ready;
         sk->sk_state_change = sc->sc_state_change;
     }
     write_unlock_bh(&sk->sk_callback_lock);
 
     return ret;
 }
 
 /*
  * this is a little helper that is called by callers who have seen a problem
  * with an sc and want to detach it from the nn if someone already hasn't beat
  * them to it.  if an error is given then the shutdown will be persistent
  * and pending transmits will be canceled.
  */
 static void o2net_ensure_shutdown(struct o2net_node *nn,
                        struct o2net_sock_container *sc,
                    int err)
 {
     spin_lock(&nn->nn_lock);
     if (nn->nn_sc == sc)
         o2net_set_nn_state(nn, NULL, 0, err);
     spin_unlock(&nn->nn_lock);
 }
 
 /*
  * This work queue function performs the blocking parts of socket shutdown.  A
  * few paths lead here.  set_nn_state will trigger this callback if it sees an
  * sc detached from the nn.  state_change will also trigger this callback
  * directly when it sees errors.  In that case we need to call set_nn_state
  * ourselves as state_change couldn't get the nn_lock and call set_nn_state
  * itself.
  */
 static void o2net_shutdown_sc(struct work_struct *work)
 {
     struct o2net_sock_container *sc =
         container_of(work, struct o2net_sock_container,
                  sc_shutdown_work);
     struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
 
     sclog(sc, "shutting down\n");
 
     /* drop the callbacks ref and call shutdown only once */
     if (o2net_unregister_callbacks(sc->sc_sock->sk, sc)) {
         /* we shouldn't flush as we're in the thread, the
          * races with pending sc work structs are harmless */
         del_timer_sync(&sc->sc_idle_timeout);
         o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
         sc_put(sc);
         kernel_sock_shutdown(sc->sc_sock, SHUT_RDWR);
     }
 
     /* not fatal so failed connects before the other guy has our
      * heartbeat can be retried */
     o2net_ensure_shutdown(nn, sc, 0);
     sc_put(sc);
 }
 
 /* ------------------------------------------------------------ */
 
 static int o2net_handler_cmp(struct o2net_msg_handler *nmh, u32 msg_type,
                  u32 key)
 {
     int ret = memcmp(&nmh->nh_key, &key, sizeof(key));
 
     if (ret == 0)
         ret = memcmp(&nmh->nh_msg_type, &msg_type, sizeof(msg_type));
 
     return ret;
 }
 
 static struct o2net_msg_handler *
 o2net_handler_tree_lookup(u32 msg_type, u32 key, struct rb_node ***ret_p,
               struct rb_node **ret_parent)
 {
     struct rb_node **p = &o2net_handler_tree.rb_node;
     struct rb_node *parent = NULL;
     struct o2net_msg_handler *nmh, *ret = NULL;
     int cmp;
 
     while (*p) {
         parent = *p;
         nmh = rb_entry(parent, struct o2net_msg_handler, nh_node);
         cmp = o2net_handler_cmp(nmh, msg_type, key);
 
         if (cmp < 0)
             p = &(*p)->rb_left;
         else if (cmp > 0)
             p = &(*p)->rb_right;
         else {
             ret = nmh;
             break;
         }
     }
 
     if (ret_p != NULL)
         *ret_p = p;
     if (ret_parent != NULL)
         *ret_parent = parent;
 
     return ret;
 }
 
 static void o2net_handler_kref_release(struct kref *kref)
 {
     struct o2net_msg_handler *nmh;
     nmh = container_of(kref, struct o2net_msg_handler, nh_kref);
 
     kfree(nmh);
 }
 
 static void o2net_handler_put(struct o2net_msg_handler *nmh)
 {
     kref_put(&nmh->nh_kref, o2net_handler_kref_release);
 }
 
 /* max_len is protection for the handler func.  incoming messages won't
  * be given to the handler if their payload is longer than the max. */
 int o2net_register_handler(u32 msg_type, u32 key, u32 max_len,
                o2net_msg_handler_func *func, void *data,
                o2net_post_msg_handler_func *post_func,
                struct list_head *unreg_list)
 {
     struct o2net_msg_handler *nmh = NULL;
     struct rb_node **p, *parent;
     int ret = 0;
 
     if (max_len > O2NET_MAX_PAYLOAD_BYTES) {
         mlog(0, "max_len for message handler out of range: %u\n",
             max_len);
         ret = -EINVAL;
         goto out;
     }
 
     if (!msg_type) {
         mlog(0, "no message type provided: %u, %p\n", msg_type, func);
         ret = -EINVAL;
         goto out;
 
     }
     if (!func) {
         mlog(0, "no message handler provided: %u, %p\n",
                msg_type, func);
         ret = -EINVAL;
         goto out;
     }
 
         nmh = kzalloc(sizeof(struct o2net_msg_handler), GFP_NOFS);
     if (nmh == NULL) {
         ret = -ENOMEM;
         goto out;
     }
 
     nmh->nh_func = func;
     nmh->nh_func_data = data;
     nmh->nh_post_func = post_func;
     nmh->nh_msg_type = msg_type;
     nmh->nh_max_len = max_len;
     nmh->nh_key = key;
     /* the tree and list get this ref.. they're both removed in
      * unregister when this ref is dropped */
     kref_init(&nmh->nh_kref);
     INIT_LIST_HEAD(&nmh->nh_unregister_item);
 
     write_lock(&o2net_handler_lock);
     if (o2net_handler_tree_lookup(msg_type, key, &p, &parent))
         ret = -EEXIST;
     else {
             rb_link_node(&nmh->nh_node, parent, p);
         rb_insert_color(&nmh->nh_node, &o2net_handler_tree);
         list_add_tail(&nmh->nh_unregister_item, unreg_list);
 
         mlog(ML_TCP, "registered handler func %p type %u key %08x\n",
              func, msg_type, key);
         /* we've had some trouble with handlers seemingly vanishing. */
         mlog_bug_on_msg(o2net_handler_tree_lookup(msg_type, key, &p,
                               &parent) == NULL,
                     "couldn't find handler we *just* registered "
                 "for type %u key %08x\n", msg_type, key);
     }
     write_unlock(&o2net_handler_lock);
 
 out:
     if (ret)
         kfree(nmh);
 
     return ret;
 }
 EXPORT_SYMBOL_GPL(o2net_register_handler);
 
 void o2net_unregister_handler_list(struct list_head *list)
 {
     struct o2net_msg_handler *nmh, *n;
 
     write_lock(&o2net_handler_lock);
     list_for_each_entry_safe(nmh, n, list, nh_unregister_item) {
         mlog(ML_TCP, "unregistering handler func %p type %u key %08x\n",
              nmh->nh_func, nmh->nh_msg_type, nmh->nh_key);
         rb_erase(&nmh->nh_node, &o2net_handler_tree);
         list_del_init(&nmh->nh_unregister_item);
         kref_put(&nmh->nh_kref, o2net_handler_kref_release);
     }
     write_unlock(&o2net_handler_lock);
 }
 EXPORT_SYMBOL_GPL(o2net_unregister_handler_list);
 
 static struct o2net_msg_handler *o2net_handler_get(u32 msg_type, u32 key)
 {
     struct o2net_msg_handler *nmh;
 
     read_lock(&o2net_handler_lock);
     nmh = o2net_handler_tree_lookup(msg_type, key, NULL, NULL);
     if (nmh)
         kref_get(&nmh->nh_kref);
     read_unlock(&o2net_handler_lock);
 
     return nmh;
 }
 
 /* ------------------------------------------------------------ */
 
 static int o2net_recv_tcp_msg(struct socket *sock, void *data, size_t len)
 {
     struct kvec vec = { .iov_len = len, .iov_base = data, };
     struct msghdr msg = { .msg_flags = MSG_DONTWAIT, };
     iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, len);
     return sock_recvmsg(sock, &msg, MSG_DONTWAIT);
 }
 
 static int o2net_send_tcp_msg(struct socket *sock, struct kvec *vec,
                   size_t veclen, size_t total)
 {
     int ret;
     struct msghdr msg = {.msg_flags = 0,};
 
     if (sock == NULL) {
         ret = -EINVAL;
         goto out;
     }
 
     ret = kernel_sendmsg(sock, &msg, vec, veclen, total);
     if (likely(ret == total))
         return 0;
     mlog(ML_ERROR, "sendmsg returned %d instead of %zu\n", ret, total);
     if (ret >= 0)
         ret = -EPIPE; /* should be smarter, I bet */
 out:
     mlog(0, "returning error: %d\n", ret);
     return ret;
 }
 
 static void o2net_sendpage(struct o2net_sock_container *sc,
                void *kmalloced_virt,
                size_t size)
 {
     struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
     ssize_t ret;
 
     while (1) {
         mutex_lock(&sc->sc_send_lock);
         ret = sc->sc_sock->ops->sendpage(sc->sc_sock,
                          virt_to_page(kmalloced_virt),
                          offset_in_page(kmalloced_virt),
                          size, MSG_DONTWAIT);
         mutex_unlock(&sc->sc_send_lock);
         if (ret == size)
             break;
         if (ret == (ssize_t)-EAGAIN) {
             mlog(0, "sendpage of size %zu to " SC_NODEF_FMT
                  " returned EAGAIN\n", size, SC_NODEF_ARGS(sc));
             cond_resched();
             continue;
         }
         mlog(ML_ERROR, "sendpage of size %zu to " SC_NODEF_FMT
              " failed with %zd\n", size, SC_NODEF_ARGS(sc), ret);
         o2net_ensure_shutdown(nn, sc, 0);
         break;
     }
 }
 
 static void o2net_init_msg(struct o2net_msg *msg, u16 data_len, u16 msg_type, u32 key)
 {
     memset(msg, 0, sizeof(struct o2net_msg));
     msg->magic = cpu_to_be16(O2NET_MSG_MAGIC);
     msg->data_len = cpu_to_be16(data_len);
     msg->msg_type = cpu_to_be16(msg_type);
     msg->sys_status = cpu_to_be32(O2NET_ERR_NONE);
     msg->status = 0;
     msg->key = cpu_to_be32(key);
 }
 
 static int o2net_tx_can_proceed(struct o2net_node *nn,
                     struct o2net_sock_container **sc_ret,
                 int *error)
 {
     int ret = 0;
 
     spin_lock(&nn->nn_lock);
     if (nn->nn_persistent_error) {
         ret = 1;
         *sc_ret = NULL;
         *error = nn->nn_persistent_error;
     } else if (nn->nn_sc_valid) {
         kref_get(&nn->nn_sc->sc_kref);
 
         ret = 1;
         *sc_ret = nn->nn_sc;
         *error = 0;
     }
     spin_unlock(&nn->nn_lock);
 
     return ret;
 }
 
 /* Get a map of all nodes to which this node is currently connected to */
 void o2net_fill_node_map(unsigned long *map, unsigned bytes)
 {
     struct o2net_sock_container *sc;
     int node, ret;
 
     BUG_ON(bytes < (BITS_TO_LONGS(O2NM_MAX_NODES) * sizeof(unsigned long)));
 
     memset(map, 0, bytes);
     for (node = 0; node < O2NM_MAX_NODES; ++node) {
         if (!o2net_tx_can_proceed(o2net_nn_from_num(node), &sc, &ret))
             continue;
         if (!ret) {
             set_bit(node, map);
             sc_put(sc);
         }
     }
 }
 EXPORT_SYMBOL_GPL(o2net_fill_node_map);
 
 int o2net_send_message_vec(u32 msg_type, u32 key, struct kvec *caller_vec,
                size_t caller_veclen, u8 target_node, int *status)
 {
     int ret = 0;
     struct o2net_msg *msg = NULL;
     size_t veclen, caller_bytes = 0;
     struct kvec *vec = NULL;
     struct o2net_sock_container *sc = NULL;
     struct o2net_node *nn = o2net_nn_from_num(target_node);
     struct o2net_status_wait nsw = {
         .ns_node_item = LIST_HEAD_INIT(nsw.ns_node_item),
     };
     struct o2net_send_tracking nst;
 
     o2net_init_nst(&nst, msg_type, key, current, target_node);
 
     if (o2net_wq == NULL) {
         mlog(0, "attempt to tx without o2netd running\n");
         ret = -ESRCH;
         goto out;
     }
 
     if (caller_veclen == 0) {
         mlog(0, "bad kvec array length\n");
         ret = -EINVAL;
         goto out;
     }
 
     caller_bytes = iov_length((struct iovec *)caller_vec, caller_veclen);
     if (caller_bytes > O2NET_MAX_PAYLOAD_BYTES) {
         mlog(0, "total payload len %zu too large\n", caller_bytes);
         ret = -EINVAL;
         goto out;
     }
 
     if (target_node == o2nm_this_node()) {
         ret = -ELOOP;
         goto out;
     }
 
     o2net_debug_add_nst(&nst);
 
     o2net_set_nst_sock_time(&nst);
 
     wait_event(nn->nn_sc_wq, o2net_tx_can_proceed(nn, &sc, &ret));
     if (ret)
         goto out;
 
     o2net_set_nst_sock_container(&nst, sc);
 
     veclen = caller_veclen + 1;
     vec = kmalloc_array(veclen, sizeof(struct kvec), GFP_ATOMIC);
     if (vec == NULL) {
         mlog(0, "failed to %zu element kvec!\n", veclen);
         ret = -ENOMEM;
         goto out;
     }
 
     msg = kmalloc(sizeof(struct o2net_msg), GFP_ATOMIC);
     if (!msg) {
         mlog(0, "failed to allocate a o2net_msg!\n");
         ret = -ENOMEM;
         goto out;
     }
 
     o2net_init_msg(msg, caller_bytes, msg_type, key);
 
     vec[0].iov_len = sizeof(struct o2net_msg);
     vec[0].iov_base = msg;
     memcpy(&vec[1], caller_vec, caller_veclen * sizeof(struct kvec));
 
     ret = o2net_prep_nsw(nn, &nsw);
     if (ret)
         goto out;
 
     msg->msg_num = cpu_to_be32(nsw.ns_id);
     o2net_set_nst_msg_id(&nst, nsw.ns_id);
 
     o2net_set_nst_send_time(&nst);
 
     /* finally, convert the message header to network byte-order
      * and send */
     mutex_lock(&sc->sc_send_lock);
     ret = o2net_send_tcp_msg(sc->sc_sock, vec, veclen,
                  sizeof(struct o2net_msg) + caller_bytes);
     mutex_unlock(&sc->sc_send_lock);
     msglog(msg, "sending returned %d\n", ret);
     if (ret < 0) {
         mlog(0, "error returned from o2net_send_tcp_msg=%d\n", ret);
         goto out;
     }
 
     /* wait on other node's handler */
     o2net_set_nst_status_time(&nst);
     wait_event(nsw.ns_wq, o2net_nsw_completed(nn, &nsw));
 
     o2net_update_send_stats(&nst, sc);
 
     /* Note that we avoid overwriting the callers status return
      * variable if a system error was reported on the other
      * side. Callers beware. */
     ret = o2net_sys_err_to_errno(nsw.ns_sys_status);
     if (status && !ret)
         *status = nsw.ns_status;
 
     mlog(0, "woken, returning system status %d, user status %d\n",
          ret, nsw.ns_status);
 out:
     o2net_debug_del_nst(&nst); /* must be before dropping sc and node */
     if (sc)
         sc_put(sc);
     kfree(vec);
     kfree(msg);
     o2net_complete_nsw(nn, &nsw, 0, 0, 0);
     return ret;
 }
 EXPORT_SYMBOL_GPL(o2net_send_message_vec);
 
 int o2net_send_message(u32 msg_type, u32 key, void *data, u32 len,
                u8 target_node, int *status)
 {
     struct kvec vec = {
         .iov_base = data,
         .iov_len = len,
     };
     return o2net_send_message_vec(msg_type, key, &vec, 1,
                       target_node, status);
 }
 EXPORT_SYMBOL_GPL(o2net_send_message);
 
 static int o2net_send_status_magic(struct socket *sock, struct o2net_msg *hdr,
                    enum o2net_system_error syserr, int err)
 {
     struct kvec vec = {
         .iov_base = hdr,
         .iov_len = sizeof(struct o2net_msg),
     };
 
     BUG_ON(syserr >= O2NET_ERR_MAX);
 
     /* leave other fields intact from the incoming message, msg_num
      * in particular */
     hdr->sys_status = cpu_to_be32(syserr);
     hdr->status = cpu_to_be32(err);
     hdr->magic = cpu_to_be16(O2NET_MSG_STATUS_MAGIC);  // twiddle the magic
     hdr->data_len = 0;
 
     msglog(hdr, "about to send status magic %d\n", err);
     /* hdr has been in host byteorder this whole time */
     return o2net_send_tcp_msg(sock, &vec, 1, sizeof(struct o2net_msg));
 }
 
 /* this returns -errno if the header was unknown or too large, etc.
  * after this is called the buffer us reused for the next message */
 static int o2net_process_message(struct o2net_sock_container *sc,
                  struct o2net_msg *hdr)
 {
     struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
     int ret = 0, handler_status;
     enum  o2net_system_error syserr;
     struct o2net_msg_handler *nmh = NULL;
     void *ret_data = NULL;
 
     msglog(hdr, "processing message\n");
 
     o2net_sc_postpone_idle(sc);
 
     switch(be16_to_cpu(hdr->magic)) {
         case O2NET_MSG_STATUS_MAGIC:
             /* special type for returning message status */
             o2net_complete_nsw(nn, NULL,
                        be32_to_cpu(hdr->msg_num),
                        be32_to_cpu(hdr->sys_status),
                        be32_to_cpu(hdr->status));
             goto out;
         case O2NET_MSG_KEEP_REQ_MAGIC:
             o2net_sendpage(sc, o2net_keep_resp,
                        sizeof(*o2net_keep_resp));
             goto out;
         case O2NET_MSG_KEEP_RESP_MAGIC:
             goto out;
         case O2NET_MSG_MAGIC:
             break;
         default:
             msglog(hdr, "bad magic\n");
             ret = -EINVAL;
             goto out;
     }
 
     /* find a handler for it */
     handler_status = 0;
     nmh = o2net_handler_get(be16_to_cpu(hdr->msg_type),
                 be32_to_cpu(hdr->key));
     if (!nmh) {
         mlog(ML_TCP, "couldn't find handler for type %u key %08x\n",
              be16_to_cpu(hdr->msg_type), be32_to_cpu(hdr->key));
         syserr = O2NET_ERR_NO_HNDLR;
         goto out_respond;
     }
 
     syserr = O2NET_ERR_NONE;
 
     if (be16_to_cpu(hdr->data_len) > nmh->nh_max_len)
         syserr = O2NET_ERR_OVERFLOW;
 
     if (syserr != O2NET_ERR_NONE)
         goto out_respond;
 
     o2net_set_func_start_time(sc);
     sc->sc_msg_key = be32_to_cpu(hdr->key);
     sc->sc_msg_type = be16_to_cpu(hdr->msg_type);
     handler_status = (nmh->nh_func)(hdr, sizeof(struct o2net_msg) +
                          be16_to_cpu(hdr->data_len),
                     nmh->nh_func_data, &ret_data);
     o2net_set_func_stop_time(sc);
 
     o2net_update_recv_stats(sc);
 
 out_respond:
     /* this destroys the hdr, so don't use it after this */
     mutex_lock(&sc->sc_send_lock);
     ret = o2net_send_status_magic(sc->sc_sock, hdr, syserr,
                       handler_status);
     mutex_unlock(&sc->sc_send_lock);
     hdr = NULL;
     mlog(0, "sending handler status %d, syserr %d returned %d\n",
          handler_status, syserr, ret);
 
     if (nmh) {
         BUG_ON(ret_data != NULL && nmh->nh_post_func == NULL);
         if (nmh->nh_post_func)
             (nmh->nh_post_func)(handler_status, nmh->nh_func_data,
                         ret_data);
     }
 
 out:
     if (nmh)
         o2net_handler_put(nmh);
     return ret;
 }
 
 static int o2net_check_handshake(struct o2net_sock_container *sc)
 {
     struct o2net_handshake *hand = page_address(sc->sc_page);
     struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
 
     if (hand->protocol_version != cpu_to_be64(O2NET_PROTOCOL_VERSION)) {
         printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " Advertised net "
                "protocol version %llu but %llu is required. "
                "Disconnecting.\n", SC_NODEF_ARGS(sc),
                (unsigned long long)be64_to_cpu(hand->protocol_version),
                O2NET_PROTOCOL_VERSION);
 
         /* don't bother reconnecting if its the wrong version. */
         o2net_ensure_shutdown(nn, sc, -ENOTCONN);
         return -1;
     }
 
     /*
      * Ensure timeouts are consistent with other nodes, otherwise
      * we can end up with one node thinking that the other must be down,
      * but isn't. This can ultimately cause corruption.
      */
     if (be32_to_cpu(hand->o2net_idle_timeout_ms) !=
                 o2net_idle_timeout()) {
         printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a network "
                "idle timeout of %u ms, but we use %u ms locally. "
                "Disconnecting.\n", SC_NODEF_ARGS(sc),
                be32_to_cpu(hand->o2net_idle_timeout_ms),
                o2net_idle_timeout());
         o2net_ensure_shutdown(nn, sc, -ENOTCONN);
         return -1;
     }
 
     if (be32_to_cpu(hand->o2net_keepalive_delay_ms) !=
             o2net_keepalive_delay()) {
         printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a keepalive "
                "delay of %u ms, but we use %u ms locally. "
                "Disconnecting.\n", SC_NODEF_ARGS(sc),
                be32_to_cpu(hand->o2net_keepalive_delay_ms),
                o2net_keepalive_delay());
         o2net_ensure_shutdown(nn, sc, -ENOTCONN);
         return -1;
     }
 
     if (be32_to_cpu(hand->o2hb_heartbeat_timeout_ms) !=
             O2HB_MAX_WRITE_TIMEOUT_MS) {
         printk(KERN_NOTICE "o2net: " SC_NODEF_FMT " uses a heartbeat "
                "timeout of %u ms, but we use %u ms locally. "
                "Disconnecting.\n", SC_NODEF_ARGS(sc),
                be32_to_cpu(hand->o2hb_heartbeat_timeout_ms),
                O2HB_MAX_WRITE_TIMEOUT_MS);
         o2net_ensure_shutdown(nn, sc, -ENOTCONN);
         return -1;
     }
 
     sc->sc_handshake_ok = 1;
 
     spin_lock(&nn->nn_lock);
     /* set valid and queue the idle timers only if it hasn't been
      * shut down already */
     if (nn->nn_sc == sc) {
         o2net_sc_reset_idle_timer(sc);
         atomic_set(&nn->nn_timeout, 0);
         o2net_set_nn_state(nn, sc, 1, 0);
     }
     spin_unlock(&nn->nn_lock);
 
     /* shift everything up as though it wasn't there */
     sc->sc_page_off -= sizeof(struct o2net_handshake);
     if (sc->sc_page_off)
         memmove(hand, hand + 1, sc->sc_page_off);
 
     return 0;
 }
 
 /* this demuxes the queued rx bytes into header or payload bits and calls
  * handlers as each full message is read off the socket.  it returns -error,
  * == 0 eof, or > 0 for progress made.*/
 static int o2net_advance_rx(struct o2net_sock_container *sc)
 {
     struct o2net_msg *hdr;
     int ret = 0;
     void *data;
     size_t datalen;
 
     sclog(sc, "receiving\n");
     o2net_set_advance_start_time(sc);
 
     if (unlikely(sc->sc_handshake_ok == 0)) {
         if(sc->sc_page_off < sizeof(struct o2net_handshake)) {
             data = page_address(sc->sc_page) + sc->sc_page_off;
             datalen = sizeof(struct o2net_handshake) - sc->sc_page_off;
             ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
             if (ret > 0)
                 sc->sc_page_off += ret;
         }
 
         if (sc->sc_page_off == sizeof(struct o2net_handshake)) {
             o2net_check_handshake(sc);
             if (unlikely(sc->sc_handshake_ok == 0))
                 ret = -EPROTO;
         }
         goto out;
     }
 
     /* do we need more header? */
     if (sc->sc_page_off < sizeof(struct o2net_msg)) {
         data = page_address(sc->sc_page) + sc->sc_page_off;
         datalen = sizeof(struct o2net_msg) - sc->sc_page_off;
         ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
         if (ret > 0) {
             sc->sc_page_off += ret;
             /* only swab incoming here.. we can
              * only get here once as we cross from
              * being under to over */
             if (sc->sc_page_off == sizeof(struct o2net_msg)) {
                 hdr = page_address(sc->sc_page);
                 if (be16_to_cpu(hdr->data_len) >
                     O2NET_MAX_PAYLOAD_BYTES)
                     ret = -EOVERFLOW;
             }
         }
         if (ret <= 0)
             goto out;
     }
 
     if (sc->sc_page_off < sizeof(struct o2net_msg)) {
         /* oof, still don't have a header */
         goto out;
     }
 
     /* this was swabbed above when we first read it */
     hdr = page_address(sc->sc_page);
 
     msglog(hdr, "at page_off %zu\n", sc->sc_page_off);
 
     /* do we need more payload? */
     if (sc->sc_page_off - sizeof(struct o2net_msg) < be16_to_cpu(hdr->data_len)) {
         /* need more payload */
         data = page_address(sc->sc_page) + sc->sc_page_off;
         datalen = (sizeof(struct o2net_msg) + be16_to_cpu(hdr->data_len)) -
               sc->sc_page_off;
         ret = o2net_recv_tcp_msg(sc->sc_sock, data, datalen);
         if (ret > 0)
             sc->sc_page_off += ret;
         if (ret <= 0)
             goto out;
     }
 
     if (sc->sc_page_off - sizeof(struct o2net_msg) == be16_to_cpu(hdr->data_len)) {
         /* we can only get here once, the first time we read
          * the payload.. so set ret to progress if the handler
          * works out. after calling this the message is toast */
         ret = o2net_process_message(sc, hdr);
         if (ret == 0)
             ret = 1;
         sc->sc_page_off = 0;
     }
 
 out:
     sclog(sc, "ret = %d\n", ret);
     o2net_set_advance_stop_time(sc);
     return ret;
 }
 
 /* this work func is triggerd by data ready.  it reads until it can read no
  * more.  it interprets 0, eof, as fatal.  if data_ready hits while we're doing
  * our work the work struct will be marked and we'll be called again. */
 static void o2net_rx_until_empty(struct work_struct *work)
 {
     struct o2net_sock_container *sc =
         container_of(work, struct o2net_sock_container, sc_rx_work);
     int ret;
 
     do {
         ret = o2net_advance_rx(sc);
     } while (ret > 0);
 
     if (ret <= 0 && ret != -EAGAIN) {
         struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
         sclog(sc, "saw error %d, closing\n", ret);
         /* not permanent so read failed handshake can retry */
         o2net_ensure_shutdown(nn, sc, 0);
     }
 
     sc_put(sc);
 }
 
 static void o2net_initialize_handshake(void)
 {
     o2net_hand->o2hb_heartbeat_timeout_ms = cpu_to_be32(
         O2HB_MAX_WRITE_TIMEOUT_MS);
     o2net_hand->o2net_idle_timeout_ms = cpu_to_be32(o2net_idle_timeout());
     o2net_hand->o2net_keepalive_delay_ms = cpu_to_be32(
         o2net_keepalive_delay());
     o2net_hand->o2net_reconnect_delay_ms = cpu_to_be32(
         o2net_reconnect_delay());
 }
 
 /* ------------------------------------------------------------ */
 
 /* called when a connect completes and after a sock is accepted.  the
  * rx path will see the response and mark the sc valid */
 static void o2net_sc_connect_completed(struct work_struct *work)
 {
     struct o2net_sock_container *sc =
         container_of(work, struct o2net_sock_container,
                  sc_connect_work);
 
     mlog(ML_MSG, "sc sending handshake with ver %llu id %llx\n",
               (unsigned long long)O2NET_PROTOCOL_VERSION,
           (unsigned long long)be64_to_cpu(o2net_hand->connector_id));
 
     o2net_initialize_handshake();
     o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
     sc_put(sc);
 }
 
 /* this is called as a work_struct func. */
 static void o2net_sc_send_keep_req(struct work_struct *work)
 {
     struct o2net_sock_container *sc =
         container_of(work, struct o2net_sock_container,
                  sc_keepalive_work.work);
 
     o2net_sendpage(sc, o2net_keep_req, sizeof(*o2net_keep_req));
     sc_put(sc);
 }
 
 /* socket shutdown does a del_timer_sync against this as it tears down.
  * we can't start this timer until we've got to the point in sc buildup
  * where shutdown is going to be involved */
 static void o2net_idle_timer(struct timer_list *t)
 {
     struct o2net_sock_container *sc = from_timer(sc, t, sc_idle_timeout);
     struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
 #ifdef CONFIG_DEBUG_FS
     unsigned long msecs = ktime_to_ms(ktime_get()) -
         ktime_to_ms(sc->sc_tv_timer);
 #else
     unsigned long msecs = o2net_idle_timeout();
 #endif
 
     printk(KERN_NOTICE "o2net: Connection to " SC_NODEF_FMT " has been "
            "idle for %lu.%lu secs.\n",
            SC_NODEF_ARGS(sc), msecs / 1000, msecs % 1000);
 
     /* idle timerout happen, don't shutdown the connection, but
      * make fence decision. Maybe the connection can recover before
      * the decision is made.
      */
     atomic_set(&nn->nn_timeout, 1);
     o2quo_conn_err(o2net_num_from_nn(nn));
     queue_delayed_work(o2net_wq, &nn->nn_still_up,
             msecs_to_jiffies(O2NET_QUORUM_DELAY_MS));
 
     o2net_sc_reset_idle_timer(sc);
 
 }
 
 static void o2net_sc_reset_idle_timer(struct o2net_sock_container *sc)
 {
     o2net_sc_cancel_delayed_work(sc, &sc->sc_keepalive_work);
     o2net_sc_queue_delayed_work(sc, &sc->sc_keepalive_work,
               msecs_to_jiffies(o2net_keepalive_delay()));
     o2net_set_sock_timer(sc);
     mod_timer(&sc->sc_idle_timeout,
            jiffies + msecs_to_jiffies(o2net_idle_timeout()));
 }
 
 static void o2net_sc_postpone_idle(struct o2net_sock_container *sc)
 {
     struct o2net_node *nn = o2net_nn_from_num(sc->sc_node->nd_num);
 
     /* clear fence decision since the connection recover from timeout*/
     if (atomic_read(&nn->nn_timeout)) {
         o2quo_conn_up(o2net_num_from_nn(nn));
         cancel_delayed_work(&nn->nn_still_up);
         atomic_set(&nn->nn_timeout, 0);
     }
 
     /* Only push out an existing timer */
     if (timer_pending(&sc->sc_idle_timeout))
         o2net_sc_reset_idle_timer(sc);
 }
 
 /* this work func is kicked whenever a path sets the nn state which doesn't
  * have valid set.  This includes seeing hb come up, losing a connection,
  * having a connect attempt fail, etc. This centralizes the logic which decides
  * if a connect attempt should be made or if we should give up and all future
  * transmit attempts should fail */
 static void o2net_start_connect(struct work_struct *work)
 {
     struct o2net_node *nn =
         container_of(work, struct o2net_node, nn_connect_work.work);
     struct o2net_sock_container *sc = NULL;
     struct o2nm_node *node = NULL, *mynode = NULL;
     struct socket *sock = NULL;
     struct sockaddr_in myaddr = {0, }, remoteaddr = {0, };
     int ret = 0, stop;
     unsigned int timeout;
     unsigned int nofs_flag;
 
     /*
      * sock_create allocates the sock with GFP_KERNEL. We must
      * prevent the filesystem from being reentered by memory reclaim.
      */
     nofs_flag = memalloc_nofs_save();
     /* if we're greater we initiate tx, otherwise we accept */
     if (o2nm_this_node() <= o2net_num_from_nn(nn))
         goto out;
 
     /* watch for racing with tearing a node down */
     node = o2nm_get_node_by_num(o2net_num_from_nn(nn));
     if (node == NULL)
         goto out;
 
     mynode = o2nm_get_node_by_num(o2nm_this_node());
     if (mynode == NULL)
         goto out;
 
     spin_lock(&nn->nn_lock);
     /*
      * see if we already have one pending or have given up.
      * For nn_timeout, it is set when we close the connection
      * because of the idle time out. So it means that we have
      * at least connected to that node successfully once,
      * now try to connect to it again.
      */
     timeout = atomic_read(&nn->nn_timeout);
     stop = (nn->nn_sc ||
         (nn->nn_persistent_error &&
         (nn->nn_persistent_error != -ENOTCONN || timeout == 0)));
     spin_unlock(&nn->nn_lock);
     if (stop)
         goto out;
 
     nn->nn_last_connect_attempt = jiffies;
 
     sc = sc_alloc(node);
     if (sc == NULL) {
         mlog(0, "couldn't allocate sc\n");
         ret = -ENOMEM;
         goto out;
     }
 
     ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
     if (ret < 0) {
         mlog(0, "can't create socket: %d\n", ret);
         goto out;
     }
     sc->sc_sock = sock; /* freed by sc_kref_release */
 
     sock->sk->sk_allocation = GFP_ATOMIC;
 
     myaddr.sin_family = AF_INET;
     myaddr.sin_addr.s_addr = mynode->nd_ipv4_address;
     myaddr.sin_port = htons(0); /* any port */
 
     ret = sock->ops->bind(sock, (struct sockaddr *)&myaddr,
                   sizeof(myaddr));
     if (ret) {
         mlog(ML_ERROR, "bind failed with %d at address %pI4\n",
              ret, &mynode->nd_ipv4_address);
         goto out;
     }
 
     tcp_sock_set_nodelay(sc->sc_sock->sk);
     tcp_sock_set_user_timeout(sock->sk, O2NET_TCP_USER_TIMEOUT);
 
     o2net_register_callbacks(sc->sc_sock->sk, sc);
 
     spin_lock(&nn->nn_lock);
     /* handshake completion will set nn->nn_sc_valid */
     o2net_set_nn_state(nn, sc, 0, 0);
     spin_unlock(&nn->nn_lock);
 
     remoteaddr.sin_family = AF_INET;
     remoteaddr.sin_addr.s_addr = node->nd_ipv4_address;
     remoteaddr.sin_port = node->nd_ipv4_port;
 
     ret = sc->sc_sock->ops->connect(sc->sc_sock,
                     (struct sockaddr *)&remoteaddr,
                     sizeof(remoteaddr),
                     O_NONBLOCK);
     if (ret == -EINPROGRESS)
         ret = 0;
 
 out:
     if (ret && sc) {
         printk(KERN_NOTICE "o2net: Connect attempt to " SC_NODEF_FMT
                " failed with errno %d\n", SC_NODEF_ARGS(sc), ret);
         /* 0 err so that another will be queued and attempted
          * from set_nn_state */
         o2net_ensure_shutdown(nn, sc, 0);
     }
     if (sc)
         sc_put(sc);
     if (node)
         o2nm_node_put(node);
     if (mynode)
         o2nm_node_put(mynode);
 
     memalloc_nofs_restore(nofs_flag);
     return;
 }
 
 static void o2net_connect_expired(struct work_struct *work)
 {
     struct o2net_node *nn =
         container_of(work, struct o2net_node, nn_connect_expired.work);
 
     spin_lock(&nn->nn_lock);
     if (!nn->nn_sc_valid) {
         printk(KERN_NOTICE "o2net: No connection established with "
                "node %u after %u.%u seconds, check network and"
                " cluster configuration.\n",
              o2net_num_from_nn(nn),
              o2net_idle_timeout() / 1000,
              o2net_idle_timeout() % 1000);
 
         o2net_set_nn_state(nn, NULL, 0, 0);
     }
     spin_unlock(&nn->nn_lock);
 }
 
 static void o2net_still_up(struct work_struct *work)
 {
     struct o2net_node *nn =
         container_of(work, struct o2net_node, nn_still_up.work);
 
     o2quo_hb_still_up(o2net_num_from_nn(nn));
 }
 
 /* ------------------------------------------------------------ */
 
 void o2net_disconnect_node(struct o2nm_node *node)
 {
     struct o2net_node *nn = o2net_nn_from_num(node->nd_num);
 
     /* don't reconnect until it's heartbeating again */
     spin_lock(&nn->nn_lock);
     atomic_set(&nn->nn_timeout, 0);
     o2net_set_nn_state(nn, NULL, 0, -ENOTCONN);
     spin_unlock(&nn->nn_lock);
 
     if (o2net_wq) {
         cancel_delayed_work(&nn->nn_connect_expired);
         cancel_delayed_work(&nn->nn_connect_work);
         cancel_delayed_work(&nn->nn_still_up);
         flush_workqueue(o2net_wq);
     }
 }
 
 static void o2net_hb_node_down_cb(struct o2nm_node *node, int node_num,
                   void *data)
 {
     o2quo_hb_down(node_num);
 
     if (!node)
         return;
 
     if (node_num != o2nm_this_node())
         o2net_disconnect_node(node);
 
     BUG_ON(atomic_read(&o2net_connected_peers) < 0);
 }
 
 static void o2net_hb_node_up_cb(struct o2nm_node *node, int node_num,
                 void *data)
 {
     struct o2net_node *nn = o2net_nn_from_num(node_num);
 
     o2quo_hb_up(node_num);
 
     BUG_ON(!node);
 
     /* ensure an immediate connect attempt */
     nn->nn_last_connect_attempt = jiffies -
         (msecs_to_jiffies(o2net_reconnect_delay()) + 1);
 
     if (node_num != o2nm_this_node()) {
         /* believe it or not, accept and node heartbeating testing
          * can succeed for this node before we got here.. so
          * only use set_nn_state to clear the persistent error
          * if that hasn't already happened */
         spin_lock(&nn->nn_lock);
         atomic_set(&nn->nn_timeout, 0);
         if (nn->nn_persistent_error)
             o2net_set_nn_state(nn, NULL, 0, 0);
         spin_unlock(&nn->nn_lock);
     }
 }
 
 void o2net_unregister_hb_callbacks(void)
 {
     o2hb_unregister_callback(NULL, &o2net_hb_up);
     o2hb_unregister_callback(NULL, &o2net_hb_down);
 }
 
 int o2net_register_hb_callbacks(void)
 {
     int ret;
 
     o2hb_setup_callback(&o2net_hb_down, O2HB_NODE_DOWN_CB,
                 o2net_hb_node_down_cb, NULL, O2NET_HB_PRI);
     o2hb_setup_callback(&o2net_hb_up, O2HB_NODE_UP_CB,
                 o2net_hb_node_up_cb, NULL, O2NET_HB_PRI);
 
     ret = o2hb_register_callback(NULL, &o2net_hb_up);
     if (ret == 0)
         ret = o2hb_register_callback(NULL, &o2net_hb_down);
 
     if (ret)
         o2net_unregister_hb_callbacks();
 
     return ret;
 }
 
 /* ------------------------------------------------------------ */
 
 static int o2net_accept_one(struct socket *sock, int *more)
 {
     int ret;
     struct sockaddr_in sin;
     struct socket *new_sock = NULL;
     struct o2nm_node *node = NULL;
     struct o2nm_node *local_node = NULL;
     struct o2net_sock_container *sc = NULL;
     struct o2net_node *nn;
     unsigned int nofs_flag;
 
     /*
      * sock_create_lite allocates the sock with GFP_KERNEL. We must
      * prevent the filesystem from being reentered by memory reclaim.
      */
     nofs_flag = memalloc_nofs_save();
 
     BUG_ON(sock == NULL);
     *more = 0;
     ret = sock_create_lite(sock->sk->sk_family, sock->sk->sk_type,
                    sock->sk->sk_protocol, &new_sock);
     if (ret)
         goto out;
 
     new_sock->type = sock->type;
     new_sock->ops = sock->ops;
     ret = sock->ops->accept(sock, new_sock, O_NONBLOCK, false);
     if (ret < 0)
         goto out;
 
     *more = 1;
     new_sock->sk->sk_allocation = GFP_ATOMIC;
 
     tcp_sock_set_nodelay(new_sock->sk);
     tcp_sock_set_user_timeout(new_sock->sk, O2NET_TCP_USER_TIMEOUT);
 
     ret = new_sock->ops->getname(new_sock, (struct sockaddr *) &sin, 1);
     if (ret < 0)
         goto out;
 
     node = o2nm_get_node_by_ip(sin.sin_addr.s_addr);
     if (node == NULL) {
         printk(KERN_NOTICE "o2net: Attempt to connect from unknown "
                "node at %pI4:%d\n", &sin.sin_addr.s_addr,
                ntohs(sin.sin_port));
         ret = -EINVAL;
         goto out;
     }
 
     if (o2nm_this_node() >= node->nd_num) {
         local_node = o2nm_get_node_by_num(o2nm_this_node());
         if (local_node)
             printk(KERN_NOTICE "o2net: Unexpected connect attempt "
                     "seen at node '%s' (%u, %pI4:%d) from "
                     "node '%s' (%u, %pI4:%d)\n",
                     local_node->nd_name, local_node->nd_num,
                     &(local_node->nd_ipv4_address),
                     ntohs(local_node->nd_ipv4_port),
                     node->nd_name,
                     node->nd_num, &sin.sin_addr.s_addr,
                     ntohs(sin.sin_port));
         ret = -EINVAL;
         goto out;
     }
 
     /* this happens all the time when the other node sees our heartbeat
      * and tries to connect before we see their heartbeat */
     if (!o2hb_check_node_heartbeating_from_callback(node->nd_num)) {
         mlog(ML_CONN, "attempt to connect from node '%s' at "
              "%pI4:%d but it isn't heartbeating\n",
              node->nd_name, &sin.sin_addr.s_addr,
              ntohs(sin.sin_port));
         ret = -EINVAL;
         goto out;
     }
 
     nn = o2net_nn_from_num(node->nd_num);
 
     spin_lock(&nn->nn_lock);
     if (nn->nn_sc)
         ret = -EBUSY;
     else
         ret = 0;
     spin_unlock(&nn->nn_lock);
     if (ret) {
         printk(KERN_NOTICE "o2net: Attempt to connect from node '%s' "
                "at %pI4:%d but it already has an open connection\n",
                node->nd_name, &sin.sin_addr.s_addr,
                ntohs(sin.sin_port));
         goto out;
     }
 
     sc = sc_alloc(node);
     if (sc == NULL) {
         ret = -ENOMEM;
         goto out;
     }
 
     sc->sc_sock = new_sock;
     new_sock = NULL;
 
     spin_lock(&nn->nn_lock);
     atomic_set(&nn->nn_timeout, 0);
     o2net_set_nn_state(nn, sc, 0, 0);
     spin_unlock(&nn->nn_lock);
 
     o2net_register_callbacks(sc->sc_sock->sk, sc);
     o2net_sc_queue_work(sc, &sc->sc_rx_work);
 
     o2net_initialize_handshake();
     o2net_sendpage(sc, o2net_hand, sizeof(*o2net_hand));
 
 out:
     if (new_sock)
         sock_release(new_sock);
     if (node)
         o2nm_node_put(node);
     if (local_node)
         o2nm_node_put(local_node);
     if (sc)
         sc_put(sc);
 
     memalloc_nofs_restore(nofs_flag);
     return ret;
 }
 
 /*
  * This function is invoked in response to one or more
  * pending accepts at softIRQ level. We must drain the
  * entire que before returning.
  */
 
 static void o2net_accept_many(struct work_struct *work)
 {
     struct socket *sock = o2net_listen_sock;
     int more;
 
     /*
      * It is critical to note that due to interrupt moderation
      * at the network driver level, we can't assume to get a
      * softIRQ for every single conn since tcp SYN packets
      * can arrive back-to-back, and therefore many pending
      * accepts may result in just 1 softIRQ. If we terminate
      * the o2net_accept_one() loop upon seeing an err, what happens
      * to the rest of the conns in the queue? If no new SYN
      * arrives for hours, no softIRQ  will be delivered,
      * and the connections will just sit in the queue.
      */
 
     for (;;) {
         o2net_accept_one(sock, &more);
         if (!more)
             break;
         cond_resched();
     }
 }
 
 static void o2net_listen_data_ready(struct sock *sk)
 {
     void (*ready)(struct sock *sk);
 
     read_lock_bh(&sk->sk_callback_lock);
     ready = sk->sk_user_data;
     if (ready == NULL) { /* check for teardown race */
         ready = sk->sk_data_ready;
         goto out;
     }
 
     /* This callback may called twice when a new connection
      * is  being established as a child socket inherits everything
      * from a parent LISTEN socket, including the data_ready cb of
      * the parent. This leads to a hazard. In o2net_accept_one()
      * we are still initializing the child socket but have not
      * changed the inherited data_ready callback yet when
      * data starts arriving.
      * We avoid this hazard by checking the state.
      * For the listening socket,  the state will be TCP_LISTEN; for the new
      * socket, will be  TCP_ESTABLISHED. Also, in this case,
      * sk->sk_user_data is not a valid function pointer.
      */
 
     if (sk->sk_state == TCP_LISTEN) {
         queue_work(o2net_wq, &o2net_listen_work);
     } else {
         ready = NULL;
     }
 
 out:
     read_unlock_bh(&sk->sk_callback_lock);
     if (ready != NULL)
         ready(sk);
 }
 
 static int o2net_open_listening_sock(__be32 addr, __be16 port)
 {
     struct socket *sock = NULL;
     int ret;
     struct sockaddr_in sin = {
         .sin_family = PF_INET,
         .sin_addr = { .s_addr = addr },
         .sin_port = port,
     };
 
     ret = sock_create(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock);
     if (ret < 0) {
         printk(KERN_ERR "o2net: Error %d while creating socket\n", ret);
         goto out;
     }
 
     sock->sk->sk_allocation = GFP_ATOMIC;
 
     write_lock_bh(&sock->sk->sk_callback_lock);
     sock->sk->sk_user_data = sock->sk->sk_data_ready;
     sock->sk->sk_data_ready = o2net_listen_data_ready;
     write_unlock_bh(&sock->sk->sk_callback_lock);
 
     o2net_listen_sock = sock;
     INIT_WORK(&o2net_listen_work, o2net_accept_many);
 
     sock->sk->sk_reuse = SK_CAN_REUSE;
     ret = sock->ops->bind(sock, (struct sockaddr *)&sin, sizeof(sin));
     if (ret < 0) {
         printk(KERN_ERR "o2net: Error %d while binding socket at "
                "%pI4:%u\n", ret, &addr, ntohs(port)); 
         goto out;
     }
 
     ret = sock->ops->listen(sock, 64);
     if (ret < 0)
         printk(KERN_ERR "o2net: Error %d while listening on %pI4:%u\n",
                ret, &addr, ntohs(port));
 
 out:
     if (ret) {
         o2net_listen_sock = NULL;
         if (sock)
             sock_release(sock);
     }
     return ret;
 }
 
 /*
  * called from node manager when we should bring up our network listening
  * socket.  node manager handles all the serialization to only call this
  * once and to match it with o2net_stop_listening().  note,
  * o2nm_this_node() doesn't work yet as we're being called while it
  * is being set up.
  */
 int o2net_start_listening(struct o2nm_node *node)
 {
     int ret = 0;
 
     BUG_ON(o2net_wq != NULL);
     BUG_ON(o2net_listen_sock != NULL);
 
     mlog(ML_KTHREAD, "starting o2net thread...\n");
     o2net_wq = alloc_ordered_workqueue("o2net", WQ_MEM_RECLAIM);
     if (o2net_wq == NULL) {
         mlog(ML_ERROR, "unable to launch o2net thread\n");
         return -ENOMEM; /* ? */
     }
 
     ret = o2net_open_listening_sock(node->nd_ipv4_address,
                     node->nd_ipv4_port);
     if (ret) {
         destroy_workqueue(o2net_wq);
         o2net_wq = NULL;
     } else
         o2quo_conn_up(node->nd_num);
 
     return ret;
 }
 
 /* again, o2nm_this_node() doesn't work here as we're involved in
  * tearing it down */
 void o2net_stop_listening(struct o2nm_node *node)
 {
     struct socket *sock = o2net_listen_sock;
     size_t i;
 
     BUG_ON(o2net_wq == NULL);
     BUG_ON(o2net_listen_sock == NULL);
 
     /* stop the listening socket from generating work */
     write_lock_bh(&sock->sk->sk_callback_lock);
     sock->sk->sk_data_ready = sock->sk->sk_user_data;
     sock->sk->sk_user_data = NULL;
     write_unlock_bh(&sock->sk->sk_callback_lock);
 
     for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
         struct o2nm_node *node = o2nm_get_node_by_num(i);
         if (node) {
             o2net_disconnect_node(node);
             o2nm_node_put(node);
         }
     }
 
     /* finish all work and tear down the work queue */
     mlog(ML_KTHREAD, "waiting for o2net thread to exit....\n");
     destroy_workqueue(o2net_wq);
     o2net_wq = NULL;
 
     sock_release(o2net_listen_sock);
     o2net_listen_sock = NULL;
 
     o2quo_conn_err(node->nd_num);
 }
 
 /* ------------------------------------------------------------ */
 
 int o2net_init(void)
 {
     unsigned long i;
 
     o2quo_init();
 
     o2net_debugfs_init();
 
     o2net_hand = kzalloc(sizeof(struct o2net_handshake), GFP_KERNEL);
     o2net_keep_req = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
     o2net_keep_resp = kzalloc(sizeof(struct o2net_msg), GFP_KERNEL);
     if (!o2net_hand || !o2net_keep_req || !o2net_keep_resp)
         goto out;
 
     o2net_hand->protocol_version = cpu_to_be64(O2NET_PROTOCOL_VERSION);
     o2net_hand->connector_id = cpu_to_be64(1);
 
     o2net_keep_req->magic = cpu_to_be16(O2NET_MSG_KEEP_REQ_MAGIC);
     o2net_keep_resp->magic = cpu_to_be16(O2NET_MSG_KEEP_RESP_MAGIC);
 
     for (i = 0; i < ARRAY_SIZE(o2net_nodes); i++) {
         struct o2net_node *nn = o2net_nn_from_num(i);
 
         atomic_set(&nn->nn_timeout, 0);
         spin_lock_init(&nn->nn_lock);
         INIT_DELAYED_WORK(&nn->nn_connect_work, o2net_start_connect);
         INIT_DELAYED_WORK(&nn->nn_connect_expired,
                   o2net_connect_expired);
         INIT_DELAYED_WORK(&nn->nn_still_up, o2net_still_up);
         /* until we see hb from a node we'll return einval */
         nn->nn_persistent_error = -ENOTCONN;
         init_waitqueue_head(&nn->nn_sc_wq);
         idr_init(&nn->nn_status_idr);
         INIT_LIST_HEAD(&nn->nn_status_list);
     }
 
     return 0;
 
 out:
     kfree(o2net_hand);
     kfree(o2net_keep_req);
     kfree(o2net_keep_resp);
     o2net_debugfs_exit();
     o2quo_exit();
     return -ENOMEM;
 }
 
 void o2net_exit(void)
 {
     o2quo_exit();
     kfree(o2net_hand);
     kfree(o2net_keep_req);
     kfree(o2net_keep_resp);
     o2net_debugfs_exit();
 }

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