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
  52 #define TIPC_SERVER_NAME_LEN    32
  53
  54 /**
  55  * struct tipc_topsrv - TIPC server structure
  56  * @conn_idr: identifier set of connection
  57  * @idr_lock: protect the connection identifier set
  58  * @idr_in_use: amount of allocated identifier entry
  59  * @net: network namspace instance
  60  * @awork: accept work item
  61  * @rcv_wq: receive workqueue
  62  * @send_wq: send workqueue
  63  * @listener: topsrv listener socket
  64  * @name: server name
  65  */
  66 struct tipc_topsrv {
  67         struct idr conn_idr;
  68         spinlock_t idr_lock; /* for idr list */
  69         int idr_in_use;
  70         struct net *net;
  71         struct work_struct awork;
  72         struct workqueue_struct *rcv_wq;
  73         struct workqueue_struct *send_wq;
  74         struct socket *listener;
  75         char name[TIPC_SERVER_NAME_LEN];
  76 };
  77
  78 /**
  79  * struct tipc_conn - TIPC connection structure
  80  * @kref: reference counter to connection object
  81  * @conid: connection identifier
  82  * @sock: socket handler associated with connection
  83  * @flags: indicates connection state
  84  * @server: pointer to connected server
  85  * @sub_list: lsit to all pertaing subscriptions
  86  * @sub_lock: lock protecting the subscription list
  87  * @rwork: receive work item
  88  * @outqueue: pointer to first outbound message in queue
  89  * @outqueue_lock: control access to the outqueue
  90  * @swork: send work item
  91  */
  92 struct tipc_conn {
  93         struct kref kref;
  94         int conid;
  95         struct socket *sock;
  96         unsigned long flags;
  97         struct tipc_topsrv *server;
  98         struct list_head sub_list;
  99         spinlock_t sub_lock; /* for subscription list */
 100         struct work_struct rwork;
 101         struct list_head outqueue;
 102         spinlock_t outqueue_lock; /* for outqueue */
 103         struct work_struct swork;
 104 };
 105
 106 /* An entry waiting to be sent */
 107 struct outqueue_entry {
 108         bool inactive;
 109         struct tipc_event evt;
 110         struct list_head list;
 111 };
 112
 113 static void tipc_conn_recv_work(struct work_struct *work);
 114 static void tipc_conn_send_work(struct work_struct *work);
 115 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt);
 116 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s);
 117
 118 static bool connected(struct tipc_conn *con)
 119 {
 120         return con && test_bit(CF_CONNECTED, &con->flags);
 121 }
 122
 123 static void tipc_conn_kref_release(struct kref *kref)
 124 {
 125         struct tipc_conn *con = container_of(kref, struct tipc_conn, kref);
 126         struct tipc_topsrv *s = con->server;
 127         struct outqueue_entry *e, *safe;
 128
 129         spin_lock_bh(&s->idr_lock);
 130         idr_remove(&s->conn_idr, con->conid);
 131         s->idr_in_use--;
 132         spin_unlock_bh(&s->idr_lock);
 133         if (con->sock)
 134                 sock_release(con->sock);
 135
 136         spin_lock_bh(&con->outqueue_lock);
 137         list_for_each_entry_safe(e, safe, &con->outqueue, list) {
 138                 list_del(&e->list);
 139                 kfree(e);
 140         }
 141         spin_unlock_bh(&con->outqueue_lock);
 142         kfree(con);
 143 }
 144
 145 static void conn_put(struct tipc_conn *con)
 146 {
 147         kref_put(&con->kref, tipc_conn_kref_release);
 148 }
 149
 150 static void conn_get(struct tipc_conn *con)
 151 {
 152         kref_get(&con->kref);
 153 }
 154
 155 static void tipc_conn_close(struct tipc_conn *con)
 156 {
 157         struct sock *sk = con->sock->sk;
 158         bool disconnect = false;
 159
 160         write_lock_bh(&sk->sk_callback_lock);
 161         disconnect = test_and_clear_bit(CF_CONNECTED, &con->flags);
 162
 163         if (disconnect) {
 164                 sk->sk_user_data = NULL;
 165                 tipc_conn_delete_sub(con, NULL);
 166         }
 167         write_unlock_bh(&sk->sk_callback_lock);
 168
 169         /* Handle concurrent calls from sending and receiving threads */
 170         if (!disconnect)
 171                 return;
 172
 173         /* Don't flush pending works, -just let them expire */
 174         kernel_sock_shutdown(con->sock, SHUT_RDWR);
 175
 176         conn_put(con);
 177 }
 178
 179 static struct tipc_conn *tipc_conn_alloc(struct tipc_topsrv *s)
 180 {
 181         struct tipc_conn *con;
 182         int ret;
 183
 184         con = kzalloc(sizeof(*con), GFP_ATOMIC);
 185         if (!con)
 186                 return ERR_PTR(-ENOMEM);
 187
 188         kref_init(&con->kref);
 189         INIT_LIST_HEAD(&con->outqueue);
 190         INIT_LIST_HEAD(&con->sub_list);
 191         spin_lock_init(&con->outqueue_lock);
 192         spin_lock_init(&con->sub_lock);
 193         INIT_WORK(&con->swork, tipc_conn_send_work);
 194         INIT_WORK(&con->rwork, tipc_conn_recv_work);
 195
 196         spin_lock_bh(&s->idr_lock);
 197         ret = idr_alloc(&s->conn_idr, con, 0, 0, GFP_ATOMIC);
 198         if (ret < 0) {
 199                 kfree(con);
 200                 spin_unlock_bh(&s->idr_lock);
 201                 return ERR_PTR(-ENOMEM);
 202         }
 203         con->conid = ret;
 204         s->idr_in_use++;
 205         spin_unlock_bh(&s->idr_lock);
 206
 207         set_bit(CF_CONNECTED, &con->flags);
 208         con->server = s;
 209
 210         return con;
 211 }
 212
 213 static struct tipc_conn *tipc_conn_lookup(struct tipc_topsrv *s, int conid)
 214 {
 215         struct tipc_conn *con;
 216
 217         spin_lock_bh(&s->idr_lock);
 218         con = idr_find(&s->conn_idr, conid);
 219         if (!connected(con) || !kref_get_unless_zero(&con->kref))
 220                 con = NULL;
 221         spin_unlock_bh(&s->idr_lock);
 222         return con;
 223 }
 224
 225 /* tipc_conn_delete_sub - delete a specific or all subscriptions
 226  * for a given subscriber
 227  */
 228 static void tipc_conn_delete_sub(struct tipc_conn *con, struct tipc_subscr *s)
 229 {
 230         struct tipc_net *tn = tipc_net(con->server->net);
 231         struct list_head *sub_list = &con->sub_list;
 232         struct tipc_subscription *sub, *tmp;
 233
 234         spin_lock_bh(&con->sub_lock);
 235         list_for_each_entry_safe(sub, tmp, sub_list, sub_list) {
 236                 if (!s || !memcmp(s, &sub->evt.s, sizeof(*s))) {
 237                         tipc_sub_unsubscribe(sub);
 238                         atomic_dec(&tn->subscription_count);
 239                         if (s)
 240                                 break;
 241                 }
 242         }
 243         spin_unlock_bh(&con->sub_lock);
 244 }
 245
 246 static void tipc_conn_send_to_sock(struct tipc_conn *con)
 247 {
 248         struct list_head *queue = &con->outqueue;
 249         struct tipc_topsrv *srv = con->server;
 250         struct outqueue_entry *e;
 251         struct tipc_event *evt;
 252         struct msghdr msg;
 253         struct kvec iov;
 254         int count = 0;
 255         int ret;
 256
 257         spin_lock_bh(&con->outqueue_lock);
 258
 259         while (!list_empty(queue)) {
 260                 e = list_first_entry(queue, struct outqueue_entry, list);
 261                 evt = &e->evt;
 262                 spin_unlock_bh(&con->outqueue_lock);
 263
 264                 if (e->inactive)
 265                         tipc_conn_delete_sub(con, &evt->s);
 266
 267                 memset(&msg, 0, sizeof(msg));
 268                 msg.msg_flags = MSG_DONTWAIT;
 269                 iov.iov_base = evt;
 270                 iov.iov_len = sizeof(*evt);
 271                 msg.msg_name = NULL;
 272
 273                 if (con->sock) {
 274                         ret = kernel_sendmsg(con->sock, &msg, &iov,
 275                                              1, sizeof(*evt));
 276                         if (ret == -EWOULDBLOCK || ret == 0) {
 277                                 cond_resched();
 278                                 return;
 279                         } else if (ret < 0) {
 280                                 return tipc_conn_close(con);
 281                         }
 282                 } else {
 283                         tipc_topsrv_kern_evt(srv->net, evt);
 284                 }
 285
 286                 /* Don't starve users filling buffers */
 287                 if (++count >= MAX_SEND_MSG_COUNT) {
 288                         cond_resched();
 289                         count = 0;
 290                 }
 291                 spin_lock_bh(&con->outqueue_lock);
 292                 list_del(&e->list);
 293                 kfree(e);
 294         }
 295         spin_unlock_bh(&con->outqueue_lock);
 296 }
 297
 298 static void tipc_conn_send_work(struct work_struct *work)
 299 {
 300         struct tipc_conn *con = container_of(work, struct tipc_conn, swork);
 301
 302         if (connected(con))
 303                 tipc_conn_send_to_sock(con);
 304
 305         conn_put(con);
 306 }
 307
 308 /* tipc_topsrv_queue_evt() - interrupt level call from a subscription instance
 309  * The queued work is launched into tipc_conn_send_work()->tipc_conn_send_to_sock()
 310  */
 311 void tipc_topsrv_queue_evt(struct net *net, int conid,
 312                            u32 event, struct tipc_event *evt)
 313 {
 314         struct tipc_topsrv *srv = tipc_topsrv(net);
 315         struct outqueue_entry *e;
 316         struct tipc_conn *con;
 317
 318         con = tipc_conn_lookup(srv, conid);
 319         if (!con)
 320                 return;
 321
 322         if (!connected(con))
 323                 goto err;
 324
 325         e = kmalloc(sizeof(*e), GFP_ATOMIC);
 326         if (!e)
 327                 goto err;
 328         e->inactive = (event == TIPC_SUBSCR_TIMEOUT);
 329         memcpy(&e->evt, evt, sizeof(*evt));
 330         spin_lock_bh(&con->outqueue_lock);
 331         list_add_tail(&e->list, &con->outqueue);
 332         spin_unlock_bh(&con->outqueue_lock);
 333
 334         if (queue_work(srv->send_wq, &con->swork))
 335                 return;
 336 err:
 337         conn_put(con);
 338 }
 339
 340 /* tipc_conn_write_space - interrupt callback after a sendmsg EAGAIN
 341  * Indicates that there now is more space in the send buffer
 342  * The queued work is launched into tipc_send_work()->tipc_conn_send_to_sock()
 343  */
 344 static void tipc_conn_write_space(struct sock *sk)
 345 {
 346         struct tipc_conn *con;
 347
 348         read_lock_bh(&sk->sk_callback_lock);
 349         con = sk->sk_user_data;
 350         if (connected(con)) {
 351                 conn_get(con);
 352                 if (!queue_work(con->server->send_wq, &con->swork))
 353                         conn_put(con);
 354         }
 355         read_unlock_bh(&sk->sk_callback_lock);
 356 }
 357
 358 static int tipc_conn_rcv_sub(struct tipc_topsrv *srv,
 359                              struct tipc_conn *con,
 360                              struct tipc_subscr *s)
 361 {
 362         struct tipc_net *tn = tipc_net(srv->net);
 363         struct tipc_subscription *sub;
 364         u32 s_filter = tipc_sub_read(s, filter);
 365
 366         if (s_filter & TIPC_SUB_CANCEL) {
 367                 tipc_sub_write(s, filter, s_filter & ~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                 /* RACE: the connection can be closed in the meantime */
 404                 if (likely(connected(con)))
 405                         ret = tipc_conn_rcv_sub(srv, con, &s);
 406                 read_unlock_bh(&sk->sk_callback_lock);
 407                 if (!ret)
 408                         return 0;
 409         }
 410
 411         tipc_conn_close(con);
 412         return ret;
 413 }
 414
 415 static void tipc_conn_recv_work(struct work_struct *work)
 416 {
 417         struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
 418         int count = 0;
 419
 420         while (connected(con)) {
 421                 if (tipc_conn_rcv_from_sock(con))
 422                         break;
 423
 424                 /* Don't flood Rx machine */
 425                 if (++count >= MAX_RECV_MSG_COUNT) {
 426                         cond_resched();
 427                         count = 0;
 428                 }
 429         }
 430         conn_put(con);
 431 }
 432
 433 /* tipc_conn_data_ready - interrupt callback indicating the socket has data
 434  * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
 435  */
 436 static void tipc_conn_data_ready(struct sock *sk)
 437 {
 438         struct tipc_conn *con;
 439
 440         read_lock_bh(&sk->sk_callback_lock);
 441         con = sk->sk_user_data;
 442         if (connected(con)) {
 443                 conn_get(con);
 444                 if (!queue_work(con->server->rcv_wq, &con->rwork))
 445                         conn_put(con);
 446         }
 447         read_unlock_bh(&sk->sk_callback_lock);
 448 }
 449
 450 static void tipc_topsrv_accept(struct work_struct *work)
 451 {
 452         struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
 453         struct socket *lsock = srv->listener;
 454         struct socket *newsock;
 455         struct tipc_conn *con;
 456         struct sock *newsk;
 457         int ret;
 458
 459         while (1) {
 460                 ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
 461                 if (ret < 0)
 462                         return;
 463                 con = tipc_conn_alloc(srv);
 464                 if (IS_ERR(con)) {
 465                         ret = PTR_ERR(con);
 466                         sock_release(newsock);
 467                         return;
 468                 }
 469                 /* Register callbacks */
 470                 newsk = newsock->sk;
 471                 write_lock_bh(&newsk->sk_callback_lock);
 472                 newsk->sk_data_ready = tipc_conn_data_ready;
 473                 newsk->sk_write_space = tipc_conn_write_space;
 474                 newsk->sk_user_data = con;
 475                 con->sock = newsock;
 476                 write_unlock_bh(&newsk->sk_callback_lock);
 477
 478                 /* Wake up receive process in case of 'SYN+' message */
 479                 newsk->sk_data_ready(newsk);
 480         }
 481 }
 482
 483 /* tipc_topsrv_listener_data_ready - interrupt callback with connection request
 484  * The queued job is launched into tipc_topsrv_accept()
 485  */
 486 static void tipc_topsrv_listener_data_ready(struct sock *sk)
 487 {
 488         struct tipc_topsrv *srv;
 489
 490         read_lock_bh(&sk->sk_callback_lock);
 491         srv = sk->sk_user_data;
 492         if (srv->listener)
 493                 queue_work(srv->rcv_wq, &srv->awork);
 494         read_unlock_bh(&sk->sk_callback_lock);
 495 }
 496
 497 static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
 498 {
 499         struct socket *lsock = NULL;
 500         struct sockaddr_tipc saddr;
 501         struct sock *sk;
 502         int rc;
 503
 504         rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
 505         if (rc < 0)
 506                 return rc;
 507
 508         srv->listener = lsock;
 509         sk = lsock->sk;
 510         write_lock_bh(&sk->sk_callback_lock);
 511         sk->sk_data_ready = tipc_topsrv_listener_data_ready;
 512         sk->sk_user_data = srv;
 513         write_unlock_bh(&sk->sk_callback_lock);
 514
 515         lock_sock(sk);
 516         rc = tsk_set_importance(sk, TIPC_CRITICAL_IMPORTANCE);
 517         release_sock(sk);
 518         if (rc < 0)
 519                 goto err;
 520
 521         saddr.family                    = AF_TIPC;
 522         saddr.addrtype                  = TIPC_SERVICE_RANGE;
 523         saddr.addr.nameseq.type = TIPC_TOP_SRV;
 524         saddr.addr.nameseq.lower        = TIPC_TOP_SRV;
 525         saddr.addr.nameseq.upper        = TIPC_TOP_SRV;
 526         saddr.scope                     = TIPC_NODE_SCOPE;
 527
 528         rc = tipc_sk_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
 529         if (rc < 0)
 530                 goto err;
 531         rc = kernel_listen(lsock, 0);
 532         if (rc < 0)
 533                 goto err;
 534
 535         /* As server's listening socket owner and creator is the same module,
 536          * we have to decrease TIPC module reference count to guarantee that
 537          * it remains zero after the server socket is created, otherwise,
 538          * executing "rmmod" command is unable to make TIPC module deleted
 539          * after TIPC module is inserted successfully.
 540          *
 541          * However, the reference count is ever increased twice in
 542          * sock_create_kern(): one is to increase the reference count of owner
 543          * of TIPC socket's proto_ops struct; another is to increment the
 544          * reference count of owner of TIPC proto struct. Therefore, we must
 545          * decrement the module reference count twice to ensure that it keeps
 546          * zero after server's listening socket is created. Of course, we
 547          * must bump the module reference count twice as well before the socket
 548          * is closed.
 549          */
 550         module_put(lsock->ops->owner);
 551         module_put(sk->sk_prot_creator->owner);
 552
 553         return 0;
 554 err:
 555         sock_release(lsock);
 556         return -EINVAL;
 557 }
 558
 559 bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
 560                              u32 upper, u32 filter, int *conid)
 561 {
 562         struct tipc_subscr sub;
 563         struct tipc_conn *con;
 564         int rc;
 565
 566         sub.seq.type = type;
 567         sub.seq.lower = lower;
 568         sub.seq.upper = upper;
 569         sub.timeout = TIPC_WAIT_FOREVER;
 570         sub.filter = filter;
 571         *(u32 *)&sub.usr_handle = port;
 572
 573         con = tipc_conn_alloc(tipc_topsrv(net));
 574         if (IS_ERR(con))
 575                 return false;
 576
 577         *conid = con->conid;
 578         con->sock = NULL;
 579         rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
 580         if (rc >= 0)
 581                 return true;
 582         conn_put(con);
 583         return false;
 584 }
 585
 586 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
 587 {
 588         struct tipc_conn *con;
 589
 590         con = tipc_conn_lookup(tipc_topsrv(net), conid);
 591         if (!con)
 592                 return;
 593
 594         test_and_clear_bit(CF_CONNECTED, &con->flags);
 595         tipc_conn_delete_sub(con, NULL);
 596         conn_put(con);
 597         conn_put(con);
 598 }
 599
 600 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
 601 {
 602         u32 port = *(u32 *)&evt->s.usr_handle;
 603         u32 self = tipc_own_addr(net);
 604         struct sk_buff_head evtq;
 605         struct sk_buff *skb;
 606
 607         skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
 608                               self, self, port, port, 0);
 609         if (!skb)
 610                 return;
 611         msg_set_dest_droppable(buf_msg(skb), true);
 612         memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
 613         skb_queue_head_init(&evtq);
 614         __skb_queue_tail(&evtq, skb);
 615         tipc_loopback_trace(net, &evtq);
 616         tipc_sk_rcv(net, &evtq);
 617 }
 618
 619 static int tipc_topsrv_work_start(struct tipc_topsrv *s)
 620 {
 621         s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
 622         if (!s->rcv_wq) {
 623                 pr_err("can't start tipc receive workqueue\n");
 624                 return -ENOMEM;
 625         }
 626
 627         s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
 628         if (!s->send_wq) {
 629                 pr_err("can't start tipc send workqueue\n");
 630                 destroy_workqueue(s->rcv_wq);
 631                 return -ENOMEM;
 632         }
 633
 634         return 0;
 635 }
 636
 637 static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
 638 {
 639         destroy_workqueue(s->rcv_wq);
 640         destroy_workqueue(s->send_wq);
 641 }
 642
 643 static int tipc_topsrv_start(struct net *net)
 644 {
 645         struct tipc_net *tn = tipc_net(net);
 646         const char name[] = "topology_server";
 647         struct tipc_topsrv *srv;
 648         int ret;
 649
 650         srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
 651         if (!srv)
 652                 return -ENOMEM;
 653
 654         srv->net = net;
 655         INIT_WORK(&srv->awork, tipc_topsrv_accept);
 656
 657         strscpy(srv->name, name, sizeof(srv->name));
 658         tn->topsrv = srv;
 659         atomic_set(&tn->subscription_count, 0);
 660
 661         spin_lock_init(&srv->idr_lock);
 662         idr_init(&srv->conn_idr);
 663         srv->idr_in_use = 0;
 664
 665         ret = tipc_topsrv_work_start(srv);
 666         if (ret < 0)
 667                 goto err_start;
 668
 669         ret = tipc_topsrv_create_listener(srv);
 670         if (ret < 0)
 671                 goto err_create;
 672
 673         return 0;
 674
 675 err_create:
 676         tipc_topsrv_work_stop(srv);
 677 err_start:
 678         kfree(srv);
 679         return ret;
 680 }
 681
 682 static void tipc_topsrv_stop(struct net *net)
 683 {
 684         struct tipc_topsrv *srv = tipc_topsrv(net);
 685         struct socket *lsock = srv->listener;
 686         struct tipc_conn *con;
 687         int id;
 688
 689         spin_lock_bh(&srv->idr_lock);
 690         for (id = 0; srv->idr_in_use; id++) {
 691                 con = idr_find(&srv->conn_idr, id);
 692                 if (con) {
 693                         spin_unlock_bh(&srv->idr_lock);
 694                         tipc_conn_close(con);
 695                         spin_lock_bh(&srv->idr_lock);
 696                 }
 697         }
 698         __module_get(lsock->ops->owner);
 699         __module_get(lsock->sk->sk_prot_creator->owner);
 700         srv->listener = NULL;
 701         spin_unlock_bh(&srv->idr_lock);
 702         sock_release(lsock);
 703         tipc_topsrv_work_stop(srv);
 704         idr_destroy(&srv->conn_idr);
 705         kfree(srv);
 706 }
 707
 708 int __net_init tipc_topsrv_init_net(struct net *net)
 709 {
 710         return tipc_topsrv_start(net);
 711 }
 712
 713 void __net_exit tipc_topsrv_exit_net(struct net *net)
 714 {
 715         tipc_topsrv_stop(net);
 716 }