net/tipc/topsrv.c

   1 /*
   2  * net/tipc/server.c: TIPC server infrastructure
   3  *
   4  * Copyright (c) 2012-2013, Wind River Systems
   5  * Copyright (c) 2017-2018, Ericsson AB
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. Neither the names of the copyright holders nor the names of its
  17  *    contributors may be used to endorse or promote products derived from
  18  *    this software without specific prior written permission.
  19  *
  20  * Alternatively, this software may be distributed under the terms of the
  21  * GNU General Public License ("GPL") version 2 as published by the Free
  22  * Software Foundation.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  25  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  28  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  34  * POSSIBILITY OF SUCH DAMAGE.
  35  */
  36
  37 #include "subscr.h"
  38 #include "topsrv.h"
  39 #include "core.h"
  40 #include "socket.h"
  41 #include "addr.h"
  42 #include "msg.h"
  43 #include "bearer.h"
  44 #include <net/sock.h>
  45 #include <linux/module.h>
  46
  47 /* Number of messages to send before rescheduling */
  48 #define MAX_SEND_MSG_COUNT      25
  49 #define MAX_RECV_MSG_COUNT      25
  50 #define CF_CONNECTED            1
  51 #define CF_SERVER               2
  52
  53 #define TIPC_SERVER_NAME_LEN    32
  54
  55 /**
  56  * struct tipc_topsrv - TIPC server structure
  57  * @conn_idr: identifier set of connection
  58  * @idr_lock: protect the connection identifier set
  59  * @idr_in_use: amount of allocated identifier entry
  60  * @net: network namspace instance
  61  * @awork: accept work item
  62  * @rcv_wq: receive workqueue
  63  * @send_wq: send workqueue
  64  * @listener: topsrv listener socket
  65  * @name: server name
  66  */
  67 struct tipc_topsrv {
  68         struct idr conn_idr;
  69         spinlock_t idr_lock; /* for idr list */
  70         int idr_in_use;
  71         struct net *net;
  72         struct work_struct awork;
  73         struct workqueue_struct *rcv_wq;
  74         struct workqueue_struct *send_wq;
  75         struct socket *listener;
  76         char name[TIPC_SERVER_NAME_LEN];
  77 };
  78
  79 /**
  80  * struct tipc_conn - TIPC connection structure
  81  * @kref: reference counter to connection object
  82  * @conid: connection identifier
  83  * @sock: socket handler associated with connection
  84  * @flags: indicates connection state
  85  * @server: pointer to connected server
  86  * @sub_list: lsit to all pertaing subscriptions
  87  * @sub_lock: lock protecting the subscription list
  88  * @rwork: receive work item
  89  * @outqueue: pointer to first outbound message in queue
  90  * @outqueue_lock: control access to the outqueue
  91  * @swork: send work item
  92  */
  93 struct tipc_conn {
  94         struct kref kref;
  95         int conid;
  96         struct socket *sock;
  97         unsigned long flags;
  98         struct tipc_topsrv *server;
  99         struct list_head sub_list;
 100         spinlock_t sub_lock; /* for subscription list */
 101         struct work_struct rwork;
 102         struct list_head outqueue;
 103         spinlock_t outqueue_lock; /* for outqueue */
 104         struct work_struct swork;
 105 };
 106
 107 /* An entry waiting to be sent */
 108 struct outqueue_entry {
 109         bool inactive;
 110         struct tipc_event evt;
 111         struct list_head list;
 112 };
 113
 114 static void tipc_conn_recv_work(struct work_struct *work);
 115 static void tipc_conn_send_work(struct work_struct *work);
 116 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
 117 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
 118
 119 static bool connected(struct tipc_conn *con)
 120 {
 121         return con && test_bit(CF_CONNECTED, &con->flags);
 122 }
 123
 124 static void tipc_conn_kref_release(struct kref *kref)
 125 {
 126         struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
 127         struct tipc_topsrv *s = con->server;
 128         struct outqueue_entry *e, *safe;
 129
 130         spin_lock_bh(&s->idr_lock);
 131         idr_remove(&s->conn_idr, con->conid);
 132         s->idr_in_use--;
 133         spin_unlock_bh(&s->idr_lock);
 134         if (con->sock)
 135                 sock_release(con->sock);
 136
 137         spin_lock_bh(&con->outqueue_lock);
 138         list_for_each_entry_safe(e, safe, &con->outqueue, list) {
 139                 list_del(&e->list);
 140                 kfree(e);
 141         }
 142         spin_unlock_bh(&con->outqueue_lock);
 143         kfree(con);
 144 }
 145
 146 static void conn_put(struct tipc_conn *con)
 147 {
 148         kref_put(&con->kref, tipc_conn_kref_release);
 149 }
 150
 151 static void conn_get(struct tipc_conn *con)
 152 {
 153         kref_get(&con->kref);
 154 }
 155
 156 static void tipc_conn_close(struct tipc_conn *con)
 157 {
 158         struct sock *sk = con->sock->sk;
 159         bool disconnect = false;
 160
 161         write_lock_bh(&sk->sk_callback_lock);
 162         disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
 163
 164         if (disconnect) {
 165                 sk->sk_user_data = NULL;
 166                 tipc_conn_delete_sub(con, NULL);
 167         }
 168         write_unlock_bh(&sk->sk_callback_lock);
 169
 170         /* Handle concurrent calls from sending and receiving threads */
 171         if (!disconnect)
 172                 return;
 173
 174         /* Don't flush pending works, -just let them expire */
 175         kernel_sock_shutdown(con->sock, SHUT_RDWR);
 176
 177         conn_put(con);
 178 }
 179
 180 static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
 181 {
 182         struct tipc_conn *con;
 183         int ret;
 184
 185         con = kzalloc(sizeof(*con), GFP_ATOMIC);
 186         if (!con)
 187                 return ERR_PTR(-ENOMEM);
 188
 189         kref_init(&con->kref);
 190         INIT_LIST_HEAD(&con->outqueue);
 191         INIT_LIST_HEAD(&con->sub_list);
 192         spin_lock_init(&con->outqueue_lock);
 193         spin_lock_init(&con->sub_lock);
 194         INIT_WORK(&con->swork, tipc_conn_send_work);
 195         INIT_WORK(&con->rwork, tipc_conn_recv_work);
 196
 197         spin_lock_bh(&s->idr_lock);
 198         ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
 199         if (ret < 0) {
 200                 kfree(con);
 201                 spin_unlock_bh(&s->idr_lock);
 202                 return ERR_PTR(-ENOMEM);
 203         }
 204         con->conid = ret;
 205         s->idr_in_use++;
 206         spin_unlock_bh(&s->idr_lock);
 207
 208         set_bit(CF_CONNECTED, &con->flags);
 209         con->server = s;
 210
 211         return con;
 212 }
 213
 214 static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
 215 {
 216         struct tipc_conn *con;
 217
 218         spin_lock_bh(&s->idr_lock);
 219         con = idr_find(&s->conn_idr, conid);
 220         if (!connected(con) || !kref_get_unless_zero(&con->kref))
 221                 con = NULL;
 222         spin_unlock_bh(&s->idr_lock);
 223         return con;
 224 }
 225
 226 /* tipc_conn_delete_sub - delete a specific or all subscriptions
 227  * for a given subscriber
 228  */
 229 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
 230 {
 231         struct tipc_net *tn = tipc_net(con->server->net);
 232         struct list_head *sub_list = &con->sub_list;
 233         struct tipc_subscription *sub, *tmp;
 234
 235         spin_lock_bh(&con->sub_lock);
 236         list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
 237                 if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
 238                         tipc_sub_unsubscribe(sub);
 239                         atomic_dec(&tn->subscription_count);
 240                 } else if (s) {
 241                         break;
 242                 }
 243         }
 244         spin_unlock_bh(&con->sub_lock);
 245 }
 246
 247 static void tipc_conn_send_to_sock(struct tipc_conn *con)
 248 {
 249         struct list_head *queue = &con->outqueue;
 250         struct tipc_topsrv *srv = con->server;
 251         struct outqueue_entry *e;
 252         struct tipc_event *evt;
 253         struct msghdr msg;
 254         struct kvec iov;
 255         int count = 0;
 256         int ret;
 257
 258         spin_lock_bh(&con->outqueue_lock);
 259
 260         while (!list_empty(queue)) {
 261                 e = list_first_entry(queue, struct outqueue_entry, list);
 262                 evt = &e->evt;
 263                 spin_unlock_bh(&con->outqueue_lock);
 264
 265                 if (e->inactive)
 266                         tipc_conn_delete_sub(con, &evt->s);
 267
 268                 memset(&msg, 0, sizeof(msg));
 269                 msg.msg_flags = MSG_DONTWAIT;
 270                 iov.iov_base = evt;
 271                 iov.iov_len = sizeof(*evt);
 272                 msg.msg_name = NULL;
 273
 274                 if (con->sock) {
 275                         ret = kernel_sendmsg(con->sock, &msg, &iov,
 276                                              1, sizeof(*evt));
 277                         if (ret == -EWOULDBLOCK || ret == 0) {
 278                                 cond_resched();
 279                                 return;
 280                         } else if (ret < 0) {
 281                                 return tipc_conn_close(con);
 282                         }
 283                 } else {
 284                         tipc_topsrv_kern_evt(srv->net, evt);
 285                 }
 286
 287                 /* Don't starve users filling buffers */
 288                 if (++count >= MAX_SEND_MSG_COUNT) {
 289                         cond_resched();
 290                         count = 0;
 291                 }
 292                 spin_lock_bh(&con->outqueue_lock);
 293                 list_del(&e->list);
 294                 kfree(e);
 295         }
 296         spin_unlock_bh(&con->outqueue_lock);
 297 }
 298
 299 static void tipc_conn_send_work(struct work_struct *work)
 300 {
 301         struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
 302
 303         if (connected(con))
 304                 tipc_conn_send_to_sock(con);
 305
 306         conn_put(con);
 307 }
 308
 309 /* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
 310  * The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
 311  */
 312 void tipc_topsrv_queue_evt(struct net *net, int conid,
 313                            u32 event, struct tipc_event *evt)
 314 {
 315         struct tipc_topsrv *srv = tipc_topsrv(net);
 316         struct outqueue_entry *e;
 317         struct tipc_conn *con;
 318
 319         con = tipc_conn_lookup(srv, conid);
 320         if (!con)
 321                 return;
 322
 323         if (!connected(con))
 324                 goto err;
 325
 326         e = kmalloc(sizeof(*e), GFP_ATOMIC);
 327         if (!e)
 328                 goto err;
 329         e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
 330         memcpy(&e->evt, evt, sizeof(*evt));
 331         spin_lock_bh(&con->outqueue_lock);
 332         list_add_tail(&e->list, &con->outqueue);
 333         spin_unlock_bh(&con->outqueue_lock);
 334
 335         if (queue_work(srv->send_wq, &con->swork))
 336                 return;
 337 err:
 338         conn_put(con);
 339 }
 340
 341 /* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
 342  * Indicates that there now is more space in the send buffer
 343  * The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
 344  */
 345 static void tipc_conn_write_space(struct sock *sk)
 346 {
 347         struct tipc_conn *con;
 348
 349         read_lock_bh(&sk->sk_callback_lock);
 350         con = sk->sk_user_data;
 351         if (connected(con)) {
 352                 conn_get(con);
 353                 if (!queue_work(con->server->send_wq, &con->swork))
 354                         conn_put(con);
 355         }
 356         read_unlock_bh(&sk->sk_callback_lock);
 357 }
 358
 359 static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
 360                              struct tipc_conn *con,
 361                              struct tipc_subscr *s)
 362 {
 363         struct tipc_net *tn = tipc_net(srv->net);
 364         struct tipc_subscription *sub;
 365
 366         if (tipc_sub_read(s, filter) & TIPC_SUB_CANCEL) {
 367                 s->filter &= __constant_ntohl(~TIPC_SUB_CANCEL);
 368                 tipc_conn_delete_sub(con, s);
 369                 return 0;
 370         }
 371         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
 372                 pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
 373                 return -1;
 374         }
 375         sub = tipc_sub_subscribe(srv->net, s, con->conid);
 376         if (!sub)
 377                 return -1;
 378         atomic_inc(&tn->subscription_count);
 379         spin_lock_bh(&con->sub_lock);
 380         list_add(&sub->sub_list, &con->sub_list);
 381         spin_unlock_bh(&con->sub_lock);
 382         return 0;
 383 }
 384
 385 static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
 386 {
 387         struct tipc_topsrv *srv = con->server;
 388         struct sock *sk = con->sock->sk;
 389         struct msghdr msg = {};
 390         struct tipc_subscr s;
 391         struct kvec iov;
 392         int ret;
 393
 394         iov.iov_base = &s;
 395         iov.iov_len = sizeof(s);
 396         msg.msg_name = NULL;
 397         iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, iov.iov_len);
 398         ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
 399         if (ret == -EWOULDBLOCK)
 400                 return -EWOULDBLOCK;
 401         if (ret == sizeof(s)) {
 402                 read_lock_bh(&sk->sk_callback_lock);
 403                 ret = tipc_conn_rcv_sub(srv, con, &s);
 404                 read_unlock_bh(&sk->sk_callback_lock);
 405         }
 406         if (ret < 0)
 407                 tipc_conn_close(con);
 408
 409         return ret;
 410 }
 411
 412 static void tipc_conn_recv_work(struct work_struct *work)
 413 {
 414         struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
 415         int count = 0;
 416
 417         while (connected(con)) {
 418                 if (tipc_conn_rcv_from_sock(con))
 419                         break;
 420
 421                 /* Don't flood Rx machine */
 422                 if (++count >= MAX_RECV_MSG_COUNT) {
 423                         cond_resched();
 424                         count = 0;
 425                 }
 426         }
 427         conn_put(con);
 428 }
 429
 430 /* tipc_conn_data_ready - interrupt callback indicating the socket has data
 431  * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
 432  */
 433 static void tipc_conn_data_ready(struct sock *sk)
 434 {
 435         struct tipc_conn *con;
 436
 437         read_lock_bh(&sk->sk_callback_lock);
 438         con = sk->sk_user_data;
 439         if (connected(con)) {
 440                 conn_get(con);
 441                 if (!queue_work(con->server->rcv_wq, &con->rwork))
 442                         conn_put(con);
 443         }
 444         read_unlock_bh(&sk->sk_callback_lock);
 445 }
 446
 447 static void tipc_topsrv_accept(struct work_struct *work)
 448 {
 449         struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
 450         struct socket *lsock = srv->listener;
 451         struct socket *newsock;
 452         struct tipc_conn *con;
 453         struct sock *newsk;
 454         int ret;
 455
 456         while (1) {
 457                 ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
 458                 if (ret < 0)
 459                         return;
 460                 con = tipc_conn_alloc(srv);
 461                 if (IS_ERR(con)) {
 462                         ret = PTR_ERR(con);
 463                         sock_release(newsock);
 464                         return;
 465                 }
 466                 /* Register callbacks */
 467                 newsk = newsock->sk;
 468                 write_lock_bh(&newsk->sk_callback_lock);
 469                 newsk->sk_data_ready = tipc_conn_data_ready;
 470                 newsk->sk_write_space = tipc_conn_write_space;
 471                 newsk->sk_user_data = con;
 472                 con->sock = newsock;
 473                 write_unlock_bh(&newsk->sk_callback_lock);
 474
 475                 /* Wake up receive process in case of 'SYN+' message */
 476                 newsk->sk_data_ready(newsk);
 477         }
 478 }
 479
 480 /* tipc_topsrv_listener_data_ready - interrupt callback with connection request
 481  * The queued job is launched into tipc_topsrv_accept()
 482  */
 483 static void tipc_topsrv_listener_data_ready(struct sock *sk)
 484 {
 485         struct tipc_topsrv *srv;
 486
 487         read_lock_bh(&sk->sk_callback_lock);
 488         srv = sk->sk_user_data;
 489         if (srv->listener)
 490                 queue_work(srv->rcv_wq, &srv->awork);
 491         read_unlock_bh(&sk->sk_callback_lock);
 492 }
 493
 494 static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
 495 {
 496         int imp = TIPC_CRITICAL_IMPORTANCE;
 497         struct socket *lsock = NULL;
 498         struct sockaddr_tipc saddr;
 499         struct sock *sk;
 500         int rc;
 501
 502         rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
 503         if (rc < 0)
 504                 return rc;
 505
 506         srv->listener = lsock;
 507         sk = lsock->sk;
 508         write_lock_bh(&sk->sk_callback_lock);
 509         sk->sk_data_ready = tipc_topsrv_listener_data_ready;
 510         sk->sk_user_data = srv;
 511         write_unlock_bh(&sk->sk_callback_lock);
 512
 513         rc = kernel_setsockopt(lsock, SOL_TIPC, TIPC_IMPORTANCE,
 514                                (char *)&imp, sizeof(imp));
 515         if (rc < 0)
 516                 goto err;
 517
 518         saddr.family                    = AF_TIPC;
 519         saddr.addrtype                  = TIPC_ADDR_NAMESEQ;
 520         saddr.addr.nameseq.type         = TIPC_TOP_SRV;
 521         saddr.addr.nameseq.lower        = TIPC_TOP_SRV;
 522         saddr.addr.nameseq.upper        = TIPC_TOP_SRV;
 523         saddr.scope                     = TIPC_NODE_SCOPE;
 524
 525         rc = kernel_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
 526         if (rc < 0)
 527                 goto err;
 528         rc = kernel_listen(lsock, 0);
 529         if (rc < 0)
 530                 goto err;
 531
 532         /* As server's listening socket owner and creator is the same module,
 533          * we have to decrease TIPC module reference count to guarantee that
 534          * it remains zero after the server socket is created, otherwise,
 535          * executing "rmmod" command is unable to make TIPC module deleted
 536          * after TIPC module is inserted successfully.
 537          *
 538          * However, the reference count is ever increased twice in
 539          * sock_create_kern(): one is to increase the reference count of owner
 540          * of TIPC socket's proto_ops struct; another is to increment the
 541          * reference count of owner of TIPC proto struct. Therefore, we must
 542          * decrement the module reference count twice to ensure that it keeps
 543          * zero after server's listening socket is created. Of course, we
 544          * must bump the module reference count twice as well before the socket
 545          * is closed.
 546          */
 547         module_put(lsock->ops->owner);
 548         module_put(sk->sk_prot_creator->owner);
 549
 550         return 0;
 551 err:
 552         sock_release(lsock);
 553         return -EINVAL;
 554 }
 555
 556 bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
 557                              u32 upper, u32 filter, int *conid)
 558 {
 559         struct tipc_subscr sub;
 560         struct tipc_conn *con;
 561         int rc;
 562
 563         sub.seq.type = type;
 564         sub.seq.lower = lower;
 565         sub.seq.upper = upper;
 566         sub.timeout = TIPC_WAIT_FOREVER;
 567         sub.filter = filter;
 568         *(u32 *)&sub.usr_handle = port;
 569
 570         con = tipc_conn_alloc(tipc_topsrv(net));
 571         if (IS_ERR(con))
 572                 return false;
 573
 574         *conid = con->conid;
 575         con->sock = NULL;
 576         rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
 577         if (rc >= 0)
 578                 return true;
 579         conn_put(con);
 580         return false;
 581 }
 582
 583 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
 584 {
 585         struct tipc_conn *con;
 586
 587         con = tipc_conn_lookup(tipc_topsrv(net), conid);
 588         if (!con)
 589                 return;
 590
 591         test_and_clear_bit(CF_CONNECTED, &con->flags);
 592         tipc_conn_delete_sub(con, NULL);
 593         conn_put(con);
 594         conn_put(con);
 595 }
 596
 597 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
 598 {
 599         u32 port = *(u32 *)&evt->s.usr_handle;
 600         u32 self = tipc_own_addr(net);
 601         struct sk_buff_head evtq;
 602         struct sk_buff *skb;
 603
 604         skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
 605                               self, self, port, port, 0);
 606         if (!skb)
 607                 return;
 608         msg_set_dest_droppable(buf_msg(skb), true);
 609         memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
 610         skb_queue_head_init(&evtq);
 611         __skb_queue_tail(&evtq, skb);
 612         tipc_loopback_trace(net, &evtq);
 613         tipc_sk_rcv(net, &evtq);
 614 }
 615
 616 static int tipc_topsrv_work_start(struct tipc_topsrv *s)
 617 {
 618         s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
 619         if (!s->rcv_wq) {
 620                 pr_err("can't start tipc receive workqueue\n");
 621                 return -ENOMEM;
 622         }
 623
 624         s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
 625         if (!s->send_wq) {
 626                 pr_err("can't start tipc send workqueue\n");
 627                 destroy_workqueue(s->rcv_wq);
 628                 return -ENOMEM;
 629         }
 630
 631         return 0;
 632 }
 633
 634 static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
 635 {
 636         destroy_workqueue(s->rcv_wq);
 637         destroy_workqueue(s->send_wq);
 638 }
 639
 640 static int tipc_topsrv_start(struct net *net)
 641 {
 642         struct tipc_net *tn = tipc_net(net);
 643         const char name[] = "topology_server";
 644         struct tipc_topsrv *srv;
 645         int ret;
 646
 647         srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
 648         if (!srv)
 649                 return -ENOMEM;
 650
 651         srv->net = net;
 652         INIT_WORK(&srv->awork, tipc_topsrv_accept);
 653
 654         strscpy(srv->name, name, sizeof(srv->name));
 655         tn->topsrv = srv;
 656         atomic_set(&tn->subscription_count, 0);
 657
 658         spin_lock_init(&srv->idr_lock);
 659         idr_init(&srv->conn_idr);
 660         srv->idr_in_use = 0;
 661
 662         ret = tipc_topsrv_work_start(srv);
 663         if (ret < 0)
 664                 return ret;
 665
 666         ret = tipc_topsrv_create_listener(srv);
 667         if (ret < 0)
 668                 tipc_topsrv_work_stop(srv);
 669
 670         return ret;
 671 }
 672
 673 static void tipc_topsrv_stop(struct net *net)
 674 {
 675         struct tipc_topsrv *srv = tipc_topsrv(net);
 676         struct socket *lsock = srv->listener;
 677         struct tipc_conn *con;
 678         int id;
 679
 680         spin_lock_bh(&srv->idr_lock);
 681         for (id = 0; srv->idr_in_use; id++) {
 682                 con = idr_find(&srv->conn_idr, id);
 683                 if (con) {
 684                         spin_unlock_bh(&srv->idr_lock);
 685                         tipc_conn_close(con);
 686                         spin_lock_bh(&srv->idr_lock);
 687                 }
 688         }
 689         __module_get(lsock->ops->owner);
 690         __module_get(lsock->sk->sk_prot_creator->owner);
 691         srv->listener = NULL;
 692         spin_unlock_bh(&srv->idr_lock);
 693         sock_release(lsock);
 694         tipc_topsrv_work_stop(srv);
 695         idr_destroy(&srv->conn_idr);
 696         kfree(srv);
 697 }
 698
 699 int __net_init tipc_topsrv_init_net(struct net *net)
 700 {
 701         return tipc_topsrv_start(net);
 702 }
 703
 704 void __net_exit tipc_topsrv_exit_net(struct net *net)
 705 {
 706         tipc_topsrv_stop(net);
 707 }