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 <net/sock.h>
  44 #include <linux/module.h>
  45
  46 /* Number of messages to send before rescheduling */
  47 #define MAX_SEND_MSG_COUNT      25
  48 #define MAX_RECV_MSG_COUNT      25
  49 #define CF_CONNECTED            1
  50 #define CF_SERVER               2
  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                 } else 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
 365         if (tipc_sub_read(s, filter) & TIPC_SUB_CANCEL) {
 366                 s->filter &= __constant_ntohl(~TIPC_SUB_CANCEL);
 367                 tipc_conn_delete_sub(con, s);
 368                 return 0;
 369         }
 370         if (atomic_read(&tn->subscription_count) >= TIPC_MAX_SUBSCR) {
 371                 pr_warn("Subscription rejected, max (%u)\n", TIPC_MAX_SUBSCR);
 372                 return -1;
 373         }
 374         sub = tipc_sub_subscribe(srv->net, s, con->conid);
 375         if (!sub)
 376                 return -1;
 377         atomic_inc(&tn->subscription_count);
 378         spin_lock_bh(&con->sub_lock);
 379         list_add(&sub->sub_list, &con->sub_list);
 380         spin_unlock_bh(&con->sub_lock);
 381         return 0;
 382 }
 383
 384 static int tipc_conn_rcv_from_sock(struct tipc_conn *con)
 385 {
 386         struct tipc_topsrv *srv = con->server;
 387         struct sock *sk = con->sock->sk;
 388         struct msghdr msg = {};
 389         struct tipc_subscr s;
 390         struct kvec iov;
 391         int ret;
 392
 393         iov.iov_base = &s;
 394         iov.iov_len = sizeof(s);
 395         msg.msg_name = NULL;
 396         iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, iov.iov_len);
 397         ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
 398         if (ret == -EWOULDBLOCK)
 399                 return -EWOULDBLOCK;
 400         if (ret == sizeof(s)) {
 401                 read_lock_bh(&sk->sk_callback_lock);
 402                 ret = tipc_conn_rcv_sub(srv, con, &s);
 403                 read_unlock_bh(&sk->sk_callback_lock);
 404         }
 405         if (ret < 0)
 406                 tipc_conn_close(con);
 407
 408         return ret;
 409 }
 410
 411 static void tipc_conn_recv_work(struct work_struct *work)
 412 {
 413         struct tipc_conn *con = container_of(work, struct tipc_conn, rwork);
 414         int count = 0;
 415
 416         while (connected(con)) {
 417                 if (tipc_conn_rcv_from_sock(con))
 418                         break;
 419
 420                 /* Don't flood Rx machine */
 421                 if (++count >= MAX_RECV_MSG_COUNT) {
 422                         cond_resched();
 423                         count = 0;
 424                 }
 425         }
 426         conn_put(con);
 427 }
 428
 429 /* tipc_conn_data_ready - interrupt callback indicating the socket has data
 430  * The queued work is launched into tipc_recv_work()->tipc_conn_rcv_from_sock()
 431  */
 432 static void tipc_conn_data_ready(struct sock *sk)
 433 {
 434         struct tipc_conn *con;
 435
 436         read_lock_bh(&sk->sk_callback_lock);
 437         con = sk->sk_user_data;
 438         if (connected(con)) {
 439                 conn_get(con);
 440                 if (!queue_work(con->server->rcv_wq, &con->rwork))
 441                         conn_put(con);
 442         }
 443         read_unlock_bh(&sk->sk_callback_lock);
 444 }
 445
 446 static void tipc_topsrv_accept(struct work_struct *work)
 447 {
 448         struct tipc_topsrv *srv = container_of(work, struct tipc_topsrv, awork);
 449         struct socket *lsock = srv->listener;
 450         struct socket *newsock;
 451         struct tipc_conn *con;
 452         struct sock *newsk;
 453         int ret;
 454
 455         while (1) {
 456                 ret = kernel_accept(lsock, &newsock, O_NONBLOCK);
 457                 if (ret < 0)
 458                         return;
 459                 con = tipc_conn_alloc(srv);
 460                 if (IS_ERR(con)) {
 461                         ret = PTR_ERR(con);
 462                         sock_release(newsock);
 463                         return;
 464                 }
 465                 /* Register callbacks */
 466                 newsk = newsock->sk;
 467                 write_lock_bh(&newsk->sk_callback_lock);
 468                 newsk->sk_data_ready = tipc_conn_data_ready;
 469                 newsk->sk_write_space = tipc_conn_write_space;
 470                 newsk->sk_user_data = con;
 471                 con->sock = newsock;
 472                 write_unlock_bh(&newsk->sk_callback_lock);
 473
 474                 /* Wake up receive process in case of 'SYN+' message */
 475                 newsk->sk_data_ready(newsk);
 476         }
 477 }
 478
 479 /* tipc_toprsv_listener_data_ready - interrupt callback with connection request
 480  * The queued job is launched into tipc_topsrv_accept()
 481  */
 482 static void tipc_topsrv_listener_data_ready(struct sock *sk)
 483 {
 484         struct tipc_topsrv *srv;
 485
 486         read_lock_bh(&sk->sk_callback_lock);
 487         srv = sk->sk_user_data;
 488         if (srv->listener)
 489                 queue_work(srv->rcv_wq, &srv->awork);
 490         read_unlock_bh(&sk->sk_callback_lock);
 491 }
 492
 493 static int tipc_topsrv_create_listener(struct tipc_topsrv *srv)
 494 {
 495         int imp = TIPC_CRITICAL_IMPORTANCE;
 496         struct socket *lsock = NULL;
 497         struct sockaddr_tipc saddr;
 498         struct sock *sk;
 499         int rc;
 500
 501         rc = sock_create_kern(srv->net, AF_TIPC, SOCK_SEQPACKET, 0, &lsock);
 502         if (rc < 0)
 503                 return rc;
 504
 505         srv->listener = lsock;
 506         sk = lsock->sk;
 507         write_lock_bh(&sk->sk_callback_lock);
 508         sk->sk_data_ready = tipc_topsrv_listener_data_ready;
 509         sk->sk_user_data = srv;
 510         write_unlock_bh(&sk->sk_callback_lock);
 511
 512         rc = kernel_setsockopt(lsock, SOL_TIPC, TIPC_IMPORTANCE,
 513                                (char *)&imp, sizeof(imp));
 514         if (rc < 0)
 515                 goto err;
 516
 517         saddr.family                    = AF_TIPC;
 518         saddr.addrtype                  = TIPC_ADDR_NAMESEQ;
 519         saddr.addr.nameseq.type         = TIPC_TOP_SRV;
 520         saddr.addr.nameseq.lower        = TIPC_TOP_SRV;
 521         saddr.addr.nameseq.upper        = TIPC_TOP_SRV;
 522         saddr.scope                     = TIPC_NODE_SCOPE;
 523
 524         rc = kernel_bind(lsock, (struct sockaddr *)&saddr, sizeof(saddr));
 525         if (rc < 0)
 526                 goto err;
 527         rc = kernel_listen(lsock, 0);
 528         if (rc < 0)
 529                 goto err;
 530
 531         /* As server's listening socket owner and creator is the same module,
 532          * we have to decrease TIPC module reference count to guarantee that
 533          * it remains zero after the server socket is created, otherwise,
 534          * executing "rmmod" command is unable to make TIPC module deleted
 535          * after TIPC module is inserted successfully.
 536          *
 537          * However, the reference count is ever increased twice in
 538          * sock_create_kern(): one is to increase the reference count of owner
 539          * of TIPC socket's proto_ops struct; another is to increment the
 540          * reference count of owner of TIPC proto struct. Therefore, we must
 541          * decrement the module reference count twice to ensure that it keeps
 542          * zero after server's listening socket is created. Of course, we
 543          * must bump the module reference count twice as well before the socket
 544          * is closed.
 545          */
 546         module_put(lsock->ops->owner);
 547         module_put(sk->sk_prot_creator->owner);
 548
 549         return 0;
 550 err:
 551         sock_release(lsock);
 552         return -EINVAL;
 553 }
 554
 555 bool tipc_topsrv_kern_subscr(struct net *net, u32 port, u32 type, u32 lower,
 556                              u32 upper, u32 filter, int *conid)
 557 {
 558         struct tipc_subscr sub;
 559         struct tipc_conn *con;
 560         int rc;
 561
 562         sub.seq.type = type;
 563         sub.seq.lower = lower;
 564         sub.seq.upper = upper;
 565         sub.timeout = TIPC_WAIT_FOREVER;
 566         sub.filter = filter;
 567         *(u32 *)&sub.usr_handle = port;
 568
 569         con = tipc_conn_alloc(tipc_topsrv(net));
 570         if (IS_ERR(con))
 571                 return false;
 572
 573         *conid = con->conid;
 574         con->sock = NULL;
 575         rc = tipc_conn_rcv_sub(tipc_topsrv(net), con, &sub);
 576         if (rc >= 0)
 577                 return true;
 578         conn_put(con);
 579         return false;
 580 }
 581
 582 void tipc_topsrv_kern_unsubscr(struct net *net, int conid)
 583 {
 584         struct tipc_conn *con;
 585
 586         con = tipc_conn_lookup(tipc_topsrv(net), conid);
 587         if (!con)
 588                 return;
 589
 590         test_and_clear_bit(CF_CONNECTED, &con->flags);
 591         tipc_conn_delete_sub(con, NULL);
 592         conn_put(con);
 593         conn_put(con);
 594 }
 595
 596 static void tipc_topsrv_kern_evt(struct net *net, struct tipc_event *evt)
 597 {
 598         u32 port = *(u32 *)&evt->s.usr_handle;
 599         u32 self = tipc_own_addr(net);
 600         struct sk_buff_head evtq;
 601         struct sk_buff *skb;
 602
 603         skb = tipc_msg_create(TOP_SRV, 0, INT_H_SIZE, sizeof(*evt),
 604                               self, self, port, port, 0);
 605         if (!skb)
 606                 return;
 607         msg_set_dest_droppable(buf_msg(skb), true);
 608         memcpy(msg_data(buf_msg(skb)), evt, sizeof(*evt));
 609         skb_queue_head_init(&evtq);
 610         __skb_queue_tail(&evtq, skb);
 611         tipc_sk_rcv(net, &evtq);
 612 }
 613
 614 static int tipc_topsrv_work_start(struct tipc_topsrv *s)
 615 {
 616         s->rcv_wq = alloc_ordered_workqueue("tipc_rcv", 0);
 617         if (!s->rcv_wq) {
 618                 pr_err("can't start tipc receive workqueue\n");
 619                 return -ENOMEM;
 620         }
 621
 622         s->send_wq = alloc_ordered_workqueue("tipc_send", 0);
 623         if (!s->send_wq) {
 624                 pr_err("can't start tipc send workqueue\n");
 625                 destroy_workqueue(s->rcv_wq);
 626                 return -ENOMEM;
 627         }
 628
 629         return 0;
 630 }
 631
 632 static void tipc_topsrv_work_stop(struct tipc_topsrv *s)
 633 {
 634         destroy_workqueue(s->rcv_wq);
 635         destroy_workqueue(s->send_wq);
 636 }
 637
 638 int tipc_topsrv_start(struct net *net)
 639 {
 640         struct tipc_net *tn = tipc_net(net);
 641         const char name[] = "topology_server";
 642         struct tipc_topsrv *srv;
 643         int ret;
 644
 645         srv = kzalloc(sizeof(*srv), GFP_ATOMIC);
 646         if (!srv)
 647                 return -ENOMEM;
 648
 649         srv->net = net;
 650         INIT_WORK(&srv->awork, tipc_topsrv_accept);
 651
 652         strscpy(srv->name, name, sizeof(srv->name));
 653         tn->topsrv = srv;
 654         atomic_set(&tn->subscription_count, 0);
 655
 656         spin_lock_init(&srv->idr_lock);
 657         idr_init(&srv->conn_idr);
 658         srv->idr_in_use = 0;
 659
 660         ret = tipc_topsrv_work_start(srv);
 661         if (ret < 0)
 662                 return ret;
 663
 664         ret = tipc_topsrv_create_listener(srv);
 665         if (ret < 0)
 666                 tipc_topsrv_work_stop(srv);
 667
 668         return ret;
 669 }
 670
 671 void tipc_topsrv_stop(struct net *net)
 672 {
 673         struct tipc_topsrv *srv = tipc_topsrv(net);
 674         struct socket *lsock = srv->listener;
 675         struct tipc_conn *con;
 676         int id;
 677
 678         spin_lock_bh(&srv->idr_lock);
 679         for (id = 0; srv->idr_in_use; id++) {
 680                 con = idr_find(&srv->conn_idr, id);
 681                 if (con) {
 682                         spin_unlock_bh(&srv->idr_lock);
 683                         tipc_conn_close(con);
 684                         spin_lock_bh(&srv->idr_lock);
 685                 }
 686         }
 687         __module_get(lsock->ops->owner);
 688         __module_get(lsock->sk->sk_prot_creator->owner);
 689         srv->listener = NULL;
 690         spin_unlock_bh(&srv->idr_lock);
 691         sock_release(lsock);
 692         tipc_topsrv_work_stop(srv);
 693         idr_destroy(&srv->conn_idr);
 694         kfree(srv);
 695 }