net/rds/tcp.c

   1 /*
   2  * Copyright (c) 2006 Oracle.  All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  */
  33 #include <linux/kernel.h>
  34 #include <linux/slab.h>
  35 #include <linux/in.h>
  36 #include <linux/module.h>
  37 #include <net/tcp.h>
  38 #include <net/net_namespace.h>
  39 #include <net/netns/generic.h>
  40
  41 #include "rds.h"
  42 #include "tcp.h"
  43
  44 /* only for info exporting */
  45 static DEFINE_SPINLOCK(rds_tcp_tc_list_lock);
  46 static LIST_HEAD(rds_tcp_tc_list);
  47 static unsigned int rds_tcp_tc_count;
  48
  49 /* Track rds_tcp_connection structs so they can be cleaned up */
  50 static DEFINE_SPINLOCK(rds_tcp_conn_lock);
  51 static LIST_HEAD(rds_tcp_conn_list);
  52
  53 static struct kmem_cache *rds_tcp_conn_slab;
  54
  55 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
  56                                  void __user *buffer, size_t *lenp,
  57                                  loff_t *fpos);
  58
  59 int rds_tcp_min_sndbuf = SOCK_MIN_SNDBUF;
  60 int rds_tcp_min_rcvbuf = SOCK_MIN_RCVBUF;
  61
  62 static struct ctl_table rds_tcp_sysctl_table[] = {
  63 #define RDS_TCP_SNDBUF  0
  64         {
  65                 .procname       = "rds_tcp_sndbuf",
  66                 /* data is per-net pointer */
  67                 .maxlen         = sizeof(int),
  68                 .mode           = 0644,
  69                 .proc_handler   = rds_tcp_skbuf_handler,
  70                 .extra1         = &rds_tcp_min_sndbuf,
  71         },
  72 #define RDS_TCP_RCVBUF  1
  73         {
  74                 .procname       = "rds_tcp_rcvbuf",
  75                 /* data is per-net pointer */
  76                 .maxlen         = sizeof(int),
  77                 .mode           = 0644,
  78                 .proc_handler   = rds_tcp_skbuf_handler,
  79                 .extra1         = &rds_tcp_min_rcvbuf,
  80         },
  81         { }
  82 };
  83
  84 /* doing it this way avoids calling tcp_sk() */
  85 void rds_tcp_nonagle(struct socket *sock)
  86 {
  87         mm_segment_t oldfs = get_fs();
  88         int val = 1;
  89
  90         set_fs(KERNEL_DS);
  91         sock->ops->setsockopt(sock, SOL_TCP, TCP_NODELAY, (char __user *)&val,
  92                               sizeof(val));
  93         set_fs(oldfs);
  94 }
  95
  96 u32 rds_tcp_snd_nxt(struct rds_tcp_connection *tc)
  97 {
  98         return tcp_sk(tc->t_sock->sk)->snd_nxt;
  99 }
 100
 101 u32 rds_tcp_snd_una(struct rds_tcp_connection *tc)
 102 {
 103         return tcp_sk(tc->t_sock->sk)->snd_una;
 104 }
 105
 106 void rds_tcp_restore_callbacks(struct socket *sock,
 107                                struct rds_tcp_connection *tc)
 108 {
 109         rdsdebug("restoring sock %p callbacks from tc %p\n", sock, tc);
 110         write_lock_bh(&sock->sk->sk_callback_lock);
 111
 112         /* done under the callback_lock to serialize with write_space */
 113         spin_lock(&rds_tcp_tc_list_lock);
 114         list_del_init(&tc->t_list_item);
 115         rds_tcp_tc_count--;
 116         spin_unlock(&rds_tcp_tc_list_lock);
 117
 118         tc->t_sock = NULL;
 119
 120         sock->sk->sk_write_space = tc->t_orig_write_space;
 121         sock->sk->sk_data_ready = tc->t_orig_data_ready;
 122         sock->sk->sk_state_change = tc->t_orig_state_change;
 123         sock->sk->sk_user_data = NULL;
 124
 125         write_unlock_bh(&sock->sk->sk_callback_lock);
 126 }
 127
 128 /*
 129  * rds_tcp_reset_callbacks() switches the to the new sock and
 130  * returns the existing tc->t_sock.
 131  *
 132  * The only functions that set tc->t_sock are rds_tcp_set_callbacks
 133  * and rds_tcp_reset_callbacks.  Send and receive trust that
 134  * it is set.  The absence of RDS_CONN_UP bit protects those paths
 135  * from being called while it isn't set.
 136  */
 137 void rds_tcp_reset_callbacks(struct socket *sock,
 138                              struct rds_connection *conn)
 139 {
 140         struct rds_tcp_connection *tc = conn->c_transport_data;
 141         struct socket *osock = tc->t_sock;
 142
 143         if (!osock)
 144                 goto newsock;
 145
 146         /* Need to resolve a duelling SYN between peers.
 147          * We have an outstanding SYN to this peer, which may
 148          * potentially have transitioned to the RDS_CONN_UP state,
 149          * so we must quiesce any send threads before resetting
 150          * c_transport_data. We quiesce these threads by setting
 151          * c_state to something other than RDS_CONN_UP, and then
 152          * waiting for any existing threads in rds_send_xmit to
 153          * complete release_in_xmit(). (Subsequent threads entering
 154          * rds_send_xmit() will bail on !rds_conn_up().
 155          *
 156          * However an incoming syn-ack at this point would end up
 157          * marking the conn as RDS_CONN_UP, and would again permit
 158          * rds_send_xmi() threads through, so ideally we would
 159          * synchronize on RDS_CONN_UP after lock_sock(), but cannot
 160          * do that: waiting on !RDS_IN_XMIT after lock_sock() may
 161          * end up deadlocking with tcp_sendmsg(), and the RDS_IN_XMIT
 162          * would not get set. As a result, we set c_state to
 163          * RDS_CONN_RESETTTING, to ensure that rds_tcp_state_change
 164          * cannot mark rds_conn_path_up() in the window before lock_sock()
 165          */
 166         atomic_set(&conn->c_state, RDS_CONN_RESETTING);
 167         wait_event(conn->c_waitq, !test_bit(RDS_IN_XMIT, &conn->c_flags));
 168         lock_sock(osock->sk);
 169         /* reset receive side state for rds_tcp_data_recv() for osock  */
 170         if (tc->t_tinc) {
 171                 rds_inc_put(&tc->t_tinc->ti_inc);
 172                 tc->t_tinc = NULL;
 173         }
 174         tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 175         tc->t_tinc_data_rem = 0;
 176         tc->t_sock = NULL;
 177
 178         write_lock_bh(&osock->sk->sk_callback_lock);
 179
 180         osock->sk->sk_user_data = NULL;
 181         osock->sk->sk_data_ready = tc->t_orig_data_ready;
 182         osock->sk->sk_write_space = tc->t_orig_write_space;
 183         osock->sk->sk_state_change = tc->t_orig_state_change;
 184         write_unlock_bh(&osock->sk->sk_callback_lock);
 185         release_sock(osock->sk);
 186         sock_release(osock);
 187 newsock:
 188         rds_send_reset(conn);
 189         lock_sock(sock->sk);
 190         write_lock_bh(&sock->sk->sk_callback_lock);
 191         tc->t_sock = sock;
 192         sock->sk->sk_user_data = conn;
 193         sock->sk->sk_data_ready = rds_tcp_data_ready;
 194         sock->sk->sk_write_space = rds_tcp_write_space;
 195         sock->sk->sk_state_change = rds_tcp_state_change;
 196
 197         write_unlock_bh(&sock->sk->sk_callback_lock);
 198         release_sock(sock->sk);
 199 }
 200
 201 /* Add tc to rds_tcp_tc_list and set tc->t_sock. See comments
 202  * above rds_tcp_reset_callbacks for notes about synchronization
 203  * with data path
 204  */
 205 void rds_tcp_set_callbacks(struct socket *sock, struct rds_connection *conn)
 206 {
 207         struct rds_tcp_connection *tc = conn->c_transport_data;
 208
 209         rdsdebug("setting sock %p callbacks to tc %p\n", sock, tc);
 210         write_lock_bh(&sock->sk->sk_callback_lock);
 211
 212         /* done under the callback_lock to serialize with write_space */
 213         spin_lock(&rds_tcp_tc_list_lock);
 214         list_add_tail(&tc->t_list_item, &rds_tcp_tc_list);
 215         rds_tcp_tc_count++;
 216         spin_unlock(&rds_tcp_tc_list_lock);
 217
 218         /* accepted sockets need our listen data ready undone */
 219         if (sock->sk->sk_data_ready == rds_tcp_listen_data_ready)
 220                 sock->sk->sk_data_ready = sock->sk->sk_user_data;
 221
 222         tc->t_sock = sock;
 223         tc->conn = conn;
 224         tc->t_orig_data_ready = sock->sk->sk_data_ready;
 225         tc->t_orig_write_space = sock->sk->sk_write_space;
 226         tc->t_orig_state_change = sock->sk->sk_state_change;
 227
 228         sock->sk->sk_user_data = conn;
 229         sock->sk->sk_data_ready = rds_tcp_data_ready;
 230         sock->sk->sk_write_space = rds_tcp_write_space;
 231         sock->sk->sk_state_change = rds_tcp_state_change;
 232
 233         write_unlock_bh(&sock->sk->sk_callback_lock);
 234 }
 235
 236 static void rds_tcp_tc_info(struct socket *sock, unsigned int len,
 237                             struct rds_info_iterator *iter,
 238                             struct rds_info_lengths *lens)
 239 {
 240         struct rds_info_tcp_socket tsinfo;
 241         struct rds_tcp_connection *tc;
 242         unsigned long flags;
 243         struct sockaddr_in sin;
 244         int sinlen;
 245
 246         spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
 247
 248         if (len / sizeof(tsinfo) < rds_tcp_tc_count)
 249                 goto out;
 250
 251         list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
 252
 253                 sock->ops->getname(sock, (struct sockaddr *)&sin, &sinlen, 0);
 254                 tsinfo.local_addr = sin.sin_addr.s_addr;
 255                 tsinfo.local_port = sin.sin_port;
 256                 sock->ops->getname(sock, (struct sockaddr *)&sin, &sinlen, 1);
 257                 tsinfo.peer_addr = sin.sin_addr.s_addr;
 258                 tsinfo.peer_port = sin.sin_port;
 259
 260                 tsinfo.hdr_rem = tc->t_tinc_hdr_rem;
 261                 tsinfo.data_rem = tc->t_tinc_data_rem;
 262                 tsinfo.last_sent_nxt = tc->t_last_sent_nxt;
 263                 tsinfo.last_expected_una = tc->t_last_expected_una;
 264                 tsinfo.last_seen_una = tc->t_last_seen_una;
 265
 266                 rds_info_copy(iter, &tsinfo, sizeof(tsinfo));
 267         }
 268
 269 out:
 270         lens->nr = rds_tcp_tc_count;
 271         lens->each = sizeof(tsinfo);
 272
 273         spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
 274 }
 275
 276 static int rds_tcp_laddr_check(struct net *net, __be32 addr)
 277 {
 278         if (inet_addr_type(net, addr) == RTN_LOCAL)
 279                 return 0;
 280         return -EADDRNOTAVAIL;
 281 }
 282
 283 static int rds_tcp_conn_alloc(struct rds_connection *conn, gfp_t gfp)
 284 {
 285         struct rds_tcp_connection *tc;
 286
 287         tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
 288         if (!tc)
 289                 return -ENOMEM;
 290
 291         mutex_init(&tc->t_conn_lock);
 292         tc->t_sock = NULL;
 293         tc->t_tinc = NULL;
 294         tc->t_tinc_hdr_rem = sizeof(struct rds_header);
 295         tc->t_tinc_data_rem = 0;
 296
 297         conn->c_transport_data = tc;
 298
 299         spin_lock_irq(&rds_tcp_conn_lock);
 300         list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
 301         spin_unlock_irq(&rds_tcp_conn_lock);
 302
 303         rdsdebug("alloced tc %p\n", conn->c_transport_data);
 304         return 0;
 305 }
 306
 307 static void rds_tcp_conn_free(void *arg)
 308 {
 309         struct rds_tcp_connection *tc = arg;
 310         unsigned long flags;
 311         rdsdebug("freeing tc %p\n", tc);
 312
 313         spin_lock_irqsave(&rds_tcp_conn_lock, flags);
 314         list_del(&tc->t_tcp_node);
 315         spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
 316
 317         kmem_cache_free(rds_tcp_conn_slab, tc);
 318 }
 319
 320 static void rds_tcp_destroy_conns(void)
 321 {
 322         struct rds_tcp_connection *tc, *_tc;
 323         LIST_HEAD(tmp_list);
 324
 325         /* avoid calling conn_destroy with irqs off */
 326         spin_lock_irq(&rds_tcp_conn_lock);
 327         list_splice(&rds_tcp_conn_list, &tmp_list);
 328         INIT_LIST_HEAD(&rds_tcp_conn_list);
 329         spin_unlock_irq(&rds_tcp_conn_lock);
 330
 331         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
 332                 if (tc->conn->c_passive)
 333                         rds_conn_destroy(tc->conn->c_passive);
 334                 rds_conn_destroy(tc->conn);
 335         }
 336 }
 337
 338 static void rds_tcp_exit(void);
 339
 340 struct rds_transport rds_tcp_transport = {
 341         .laddr_check            = rds_tcp_laddr_check,
 342         .xmit_prepare           = rds_tcp_xmit_prepare,
 343         .xmit_complete          = rds_tcp_xmit_complete,
 344         .xmit                   = rds_tcp_xmit,
 345         .recv                   = rds_tcp_recv,
 346         .conn_alloc             = rds_tcp_conn_alloc,
 347         .conn_free              = rds_tcp_conn_free,
 348         .conn_connect           = rds_tcp_conn_connect,
 349         .conn_shutdown          = rds_tcp_conn_shutdown,
 350         .inc_copy_to_user       = rds_tcp_inc_copy_to_user,
 351         .inc_free               = rds_tcp_inc_free,
 352         .stats_info_copy        = rds_tcp_stats_info_copy,
 353         .exit                   = rds_tcp_exit,
 354         .t_owner                = THIS_MODULE,
 355         .t_name                 = "tcp",
 356         .t_type                 = RDS_TRANS_TCP,
 357         .t_prefer_loopback      = 1,
 358 };
 359
 360 static int rds_tcp_netid;
 361
 362 /* per-network namespace private data for this module */
 363 struct rds_tcp_net {
 364         struct socket *rds_tcp_listen_sock;
 365         struct work_struct rds_tcp_accept_w;
 366         struct ctl_table_header *rds_tcp_sysctl;
 367         struct ctl_table *ctl_table;
 368         int sndbuf_size;
 369         int rcvbuf_size;
 370 };
 371
 372 /* All module specific customizations to the RDS-TCP socket should be done in
 373  * rds_tcp_tune() and applied after socket creation.
 374  */
 375 void rds_tcp_tune(struct socket *sock)
 376 {
 377         struct sock *sk = sock->sk;
 378         struct net *net = sock_net(sk);
 379         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 380
 381         rds_tcp_nonagle(sock);
 382         lock_sock(sk);
 383         if (rtn->sndbuf_size > 0) {
 384                 sk->sk_sndbuf = rtn->sndbuf_size;
 385                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
 386         }
 387         if (rtn->rcvbuf_size > 0) {
 388                 sk->sk_sndbuf = rtn->rcvbuf_size;
 389                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
 390         }
 391         release_sock(sk);
 392 }
 393
 394 static void rds_tcp_accept_worker(struct work_struct *work)
 395 {
 396         struct rds_tcp_net *rtn = container_of(work,
 397                                                struct rds_tcp_net,
 398                                                rds_tcp_accept_w);
 399
 400         while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
 401                 cond_resched();
 402 }
 403
 404 void rds_tcp_accept_work(struct sock *sk)
 405 {
 406         struct net *net = sock_net(sk);
 407         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 408
 409         queue_work(rds_wq, &rtn->rds_tcp_accept_w);
 410 }
 411
 412 static __net_init int rds_tcp_init_net(struct net *net)
 413 {
 414         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 415         struct ctl_table *tbl;
 416         int err = 0;
 417
 418         memset(rtn, 0, sizeof(*rtn));
 419
 420         /* {snd, rcv}buf_size default to 0, which implies we let the
 421          * stack pick the value, and permit auto-tuning of buffer size.
 422          */
 423         if (net == &init_net) {
 424                 tbl = rds_tcp_sysctl_table;
 425         } else {
 426                 tbl = kmemdup(rds_tcp_sysctl_table,
 427                               sizeof(rds_tcp_sysctl_table), GFP_KERNEL);
 428                 if (!tbl) {
 429                         pr_warn("could not set allocate syctl table\n");
 430                         return -ENOMEM;
 431                 }
 432                 rtn->ctl_table = tbl;
 433         }
 434         tbl[RDS_TCP_SNDBUF].data = &rtn->sndbuf_size;
 435         tbl[RDS_TCP_RCVBUF].data = &rtn->rcvbuf_size;
 436         rtn->rds_tcp_sysctl = register_net_sysctl(net, "net/rds/tcp", tbl);
 437         if (!rtn->rds_tcp_sysctl) {
 438                 pr_warn("could not register sysctl\n");
 439                 err = -ENOMEM;
 440                 goto fail;
 441         }
 442         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net);
 443         if (!rtn->rds_tcp_listen_sock) {
 444                 pr_warn("could not set up listen sock\n");
 445                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
 446                 rtn->rds_tcp_sysctl = NULL;
 447                 err = -EAFNOSUPPORT;
 448                 goto fail;
 449         }
 450         INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
 451         return 0;
 452
 453 fail:
 454         if (net != &init_net)
 455                 kfree(tbl);
 456         return err;
 457 }
 458
 459 static void __net_exit rds_tcp_exit_net(struct net *net)
 460 {
 461         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 462
 463         if (rtn->rds_tcp_sysctl)
 464                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
 465
 466         if (net != &init_net && rtn->ctl_table)
 467                 kfree(rtn->ctl_table);
 468
 469         /* If rds_tcp_exit_net() is called as a result of netns deletion,
 470          * the rds_tcp_kill_sock() device notifier would already have cleaned
 471          * up the listen socket, thus there is no work to do in this function.
 472          *
 473          * If rds_tcp_exit_net() is called as a result of module unload,
 474          * i.e., due to rds_tcp_exit() -> unregister_pernet_subsys(), then
 475          * we do need to clean up the listen socket here.
 476          */
 477         if (rtn->rds_tcp_listen_sock) {
 478                 rds_tcp_listen_stop(rtn->rds_tcp_listen_sock);
 479                 rtn->rds_tcp_listen_sock = NULL;
 480                 flush_work(&rtn->rds_tcp_accept_w);
 481         }
 482 }
 483
 484 static struct pernet_operations rds_tcp_net_ops = {
 485         .init = rds_tcp_init_net,
 486         .exit = rds_tcp_exit_net,
 487         .id = &rds_tcp_netid,
 488         .size = sizeof(struct rds_tcp_net),
 489 };
 490
 491 static void rds_tcp_kill_sock(struct net *net)
 492 {
 493         struct rds_tcp_connection *tc, *_tc;
 494         struct sock *sk;
 495         LIST_HEAD(tmp_list);
 496         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
 497
 498         rds_tcp_listen_stop(rtn->rds_tcp_listen_sock);
 499         rtn->rds_tcp_listen_sock = NULL;
 500         flush_work(&rtn->rds_tcp_accept_w);
 501         spin_lock_irq(&rds_tcp_conn_lock);
 502         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 503                 struct net *c_net = read_pnet(&tc->conn->c_net);
 504
 505                 if (net != c_net || !tc->t_sock)
 506                         continue;
 507                 list_move_tail(&tc->t_tcp_node, &tmp_list);
 508         }
 509         spin_unlock_irq(&rds_tcp_conn_lock);
 510         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
 511                 sk = tc->t_sock->sk;
 512                 sk->sk_prot->disconnect(sk, 0);
 513                 tcp_done(sk);
 514                 if (tc->conn->c_passive)
 515                         rds_conn_destroy(tc->conn->c_passive);
 516                 rds_conn_destroy(tc->conn);
 517         }
 518 }
 519
 520 static int rds_tcp_dev_event(struct notifier_block *this,
 521                              unsigned long event, void *ptr)
 522 {
 523         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 524
 525         /* rds-tcp registers as a pernet subys, so the ->exit will only
 526          * get invoked after network acitivity has quiesced. We need to
 527          * clean up all sockets  to quiesce network activity, and use
 528          * the unregistration of the per-net loopback device as a trigger
 529          * to start that cleanup.
 530          */
 531         if (event == NETDEV_UNREGISTER_FINAL &&
 532             dev->ifindex == LOOPBACK_IFINDEX)
 533                 rds_tcp_kill_sock(dev_net(dev));
 534
 535         return NOTIFY_DONE;
 536 }
 537
 538 static struct notifier_block rds_tcp_dev_notifier = {
 539         .notifier_call        = rds_tcp_dev_event,
 540         .priority = -10, /* must be called after other network notifiers */
 541 };
 542
 543 /* when sysctl is used to modify some kernel socket parameters,this
 544  * function  resets the RDS connections in that netns  so that we can
 545  * restart with new parameters.  The assumption is that such reset
 546  * events are few and far-between.
 547  */
 548 static void rds_tcp_sysctl_reset(struct net *net)
 549 {
 550         struct rds_tcp_connection *tc, *_tc;
 551
 552         spin_lock_irq(&rds_tcp_conn_lock);
 553         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
 554                 struct net *c_net = read_pnet(&tc->conn->c_net);
 555
 556                 if (net != c_net || !tc->t_sock)
 557                         continue;
 558
 559                 rds_conn_drop(tc->conn); /* reconnect with new parameters */
 560         }
 561         spin_unlock_irq(&rds_tcp_conn_lock);
 562 }
 563
 564 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
 565                                  void __user *buffer, size_t *lenp,
 566                                  loff_t *fpos)
 567 {
 568         struct net *net = current->nsproxy->net_ns;
 569         int err;
 570
 571         err = proc_dointvec_minmax(ctl, write, buffer, lenp, fpos);
 572         if (err < 0) {
 573                 pr_warn("Invalid input. Must be >= %d\n",
 574                         *(int *)(ctl->extra1));
 575                 return err;
 576         }
 577         if (write)
 578                 rds_tcp_sysctl_reset(net);
 579         return 0;
 580 }
 581
 582 static void rds_tcp_exit(void)
 583 {
 584         rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 585         unregister_pernet_subsys(&rds_tcp_net_ops);
 586         if (unregister_netdevice_notifier(&rds_tcp_dev_notifier))
 587                 pr_warn("could not unregister rds_tcp_dev_notifier\n");
 588         rds_tcp_destroy_conns();
 589         rds_trans_unregister(&rds_tcp_transport);
 590         rds_tcp_recv_exit();
 591         kmem_cache_destroy(rds_tcp_conn_slab);
 592 }
 593 module_exit(rds_tcp_exit);
 594
 595 static int rds_tcp_init(void)
 596 {
 597         int ret;
 598
 599         rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
 600                                               sizeof(struct rds_tcp_connection),
 601                                               0, 0, NULL);
 602         if (!rds_tcp_conn_slab) {
 603                 ret = -ENOMEM;
 604                 goto out;
 605         }
 606
 607         ret = register_netdevice_notifier(&rds_tcp_dev_notifier);
 608         if (ret) {
 609                 pr_warn("could not register rds_tcp_dev_notifier\n");
 610                 goto out;
 611         }
 612
 613         ret = register_pernet_subsys(&rds_tcp_net_ops);
 614         if (ret)
 615                 goto out_slab;
 616
 617         ret = rds_tcp_recv_init();
 618         if (ret)
 619                 goto out_slab;
 620
 621         ret = rds_trans_register(&rds_tcp_transport);
 622         if (ret)
 623                 goto out_recv;
 624
 625         rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
 626
 627         goto out;
 628
 629 out_recv:
 630         rds_tcp_recv_exit();
 631 out_slab:
 632         unregister_pernet_subsys(&rds_tcp_net_ops);
 633         kmem_cache_destroy(rds_tcp_conn_slab);
 634 out:
 635         return ret;
 636 }
 637 module_init(rds_tcp_init);
 638
 639 MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
 640 MODULE_DESCRIPTION("RDS: TCP transport");
 641 MODULE_LICENSE("Dual BSD/GPL");
 642