net/rds/connection.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/list.h>
  35 #include <linux/slab.h>
  36 #include <linux/export.h>
  37 #include <net/inet_hashtables.h>
  38
  39 #include "rds.h"
  40 #include "loop.h"
  41
  42 #define RDS_CONNECTION_HASH_BITS 12
  43 #define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
  44 #define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
  45
  46 /* converting this to RCU is a chore for another day.. */
  47 static DEFINE_SPINLOCK(rds_conn_lock);
  48 static unsigned long rds_conn_count;
  49 static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
  50 static struct kmem_cache *rds_conn_slab;
  51
  52 static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
  53 {
  54         static u32 rds_hash_secret __read_mostly;
  55
  56         unsigned long hash;
  57
  58         net_get_random_once(&rds_hash_secret, sizeof(rds_hash_secret));
  59
  60         /* Pass NULL, don't need struct net for hash */
  61         hash = __inet_ehashfn(be32_to_cpu(laddr), 0,
  62                               be32_to_cpu(faddr), 0,
  63                               rds_hash_secret);
  64         return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
  65 }
  66
  67 #define rds_conn_info_set(var, test, suffix) do {               \
  68         if (test)                                               \
  69                 var |= RDS_INFO_CONNECTION_FLAG_##suffix;       \
  70 } while (0)
  71
  72 /* rcu read lock must be held or the connection spinlock */
  73 static struct rds_connection *rds_conn_lookup(struct net *net,
  74                                               struct hlist_head *head,
  75                                               __be32 laddr, __be32 faddr,
  76                                               struct rds_transport *trans)
  77 {
  78         struct rds_connection *conn, *ret = NULL;
  79
  80         hlist_for_each_entry_rcu(conn, head, c_hash_node) {
  81                 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
  82                     conn->c_trans == trans && net == rds_conn_net(conn)) {
  83                         ret = conn;
  84                         break;
  85                 }
  86         }
  87         rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
  88                  &laddr, &faddr);
  89         return ret;
  90 }
  91
  92 /*
  93  * This is called by transports as they're bringing down a connection.
  94  * It clears partial message state so that the transport can start sending
  95  * and receiving over this connection again in the future.  It is up to
  96  * the transport to have serialized this call with its send and recv.
  97  */
  98 static void rds_conn_path_reset(struct rds_conn_path *cp)
  99 {
 100         struct rds_connection *conn = cp->cp_conn;
 101
 102         rdsdebug("connection %pI4 to %pI4 reset\n",
 103           &conn->c_laddr, &conn->c_faddr);
 104
 105         rds_stats_inc(s_conn_reset);
 106         rds_send_path_reset(cp);
 107         cp->cp_flags = 0;
 108
 109         /* Do not clear next_rx_seq here, else we cannot distinguish
 110          * retransmitted packets from new packets, and will hand all
 111          * of them to the application. That is not consistent with the
 112          * reliability guarantees of RDS. */
 113 }
 114
 115 static void __rds_conn_path_init(struct rds_connection *conn,
 116                                  struct rds_conn_path *cp, bool is_outgoing)
 117 {
 118         spin_lock_init(&cp->cp_lock);
 119         cp->cp_next_tx_seq = 1;
 120         init_waitqueue_head(&cp->cp_waitq);
 121         INIT_LIST_HEAD(&cp->cp_send_queue);
 122         INIT_LIST_HEAD(&cp->cp_retrans);
 123
 124         cp->cp_conn = conn;
 125         atomic_set(&cp->cp_state, RDS_CONN_DOWN);
 126         cp->cp_send_gen = 0;
 127         /* cp_outgoing is per-path. So we can only set it here
 128          * for the single-path transports.
 129          */
 130         if (!conn->c_trans->t_mp_capable)
 131                 cp->cp_outgoing = (is_outgoing ? 1 : 0);
 132         cp->cp_reconnect_jiffies = 0;
 133         INIT_DELAYED_WORK(&cp->cp_send_w, rds_send_worker);
 134         INIT_DELAYED_WORK(&cp->cp_recv_w, rds_recv_worker);
 135         INIT_DELAYED_WORK(&cp->cp_conn_w, rds_connect_worker);
 136         INIT_WORK(&cp->cp_down_w, rds_shutdown_worker);
 137         mutex_init(&cp->cp_cm_lock);
 138         cp->cp_flags = 0;
 139 }
 140
 141 /*
 142  * There is only every one 'conn' for a given pair of addresses in the
 143  * system at a time.  They contain messages to be retransmitted and so
 144  * span the lifetime of the actual underlying transport connections.
 145  *
 146  * For now they are not garbage collected once they're created.  They
 147  * are torn down as the module is removed, if ever.
 148  */
 149 static struct rds_connection *__rds_conn_create(struct net *net,
 150                                                 __be32 laddr, __be32 faddr,
 151                                        struct rds_transport *trans, gfp_t gfp,
 152                                        int is_outgoing)
 153 {
 154         struct rds_connection *conn, *parent = NULL;
 155         struct hlist_head *head = rds_conn_bucket(laddr, faddr);
 156         struct rds_transport *loop_trans;
 157         unsigned long flags;
 158         int ret, i;
 159
 160         rcu_read_lock();
 161         conn = rds_conn_lookup(net, head, laddr, faddr, trans);
 162         if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
 163             laddr == faddr && !is_outgoing) {
 164                 /* This is a looped back IB connection, and we're
 165                  * called by the code handling the incoming connect.
 166                  * We need a second connection object into which we
 167                  * can stick the other QP. */
 168                 parent = conn;
 169                 conn = parent->c_passive;
 170         }
 171         rcu_read_unlock();
 172         if (conn)
 173                 goto out;
 174
 175         conn = kmem_cache_zalloc(rds_conn_slab, gfp);
 176         if (!conn) {
 177                 conn = ERR_PTR(-ENOMEM);
 178                 goto out;
 179         }
 180
 181         INIT_HLIST_NODE(&conn->c_hash_node);
 182         conn->c_laddr = laddr;
 183         conn->c_faddr = faddr;
 184
 185         rds_conn_net_set(conn, net);
 186
 187         ret = rds_cong_get_maps(conn);
 188         if (ret) {
 189                 kmem_cache_free(rds_conn_slab, conn);
 190                 conn = ERR_PTR(ret);
 191                 goto out;
 192         }
 193
 194         /*
 195          * This is where a connection becomes loopback.  If *any* RDS sockets
 196          * can bind to the destination address then we'd rather the messages
 197          * flow through loopback rather than either transport.
 198          */
 199         loop_trans = rds_trans_get_preferred(net, faddr);
 200         if (loop_trans) {
 201                 rds_trans_put(loop_trans);
 202                 conn->c_loopback = 1;
 203                 if (is_outgoing && trans->t_prefer_loopback) {
 204                         /* "outgoing" connection - and the transport
 205                          * says it wants the connection handled by the
 206                          * loopback transport. This is what TCP does.
 207                          */
 208                         trans = &rds_loop_transport;
 209                 }
 210         }
 211
 212         conn->c_trans = trans;
 213
 214         init_waitqueue_head(&conn->c_hs_waitq);
 215         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
 216                 __rds_conn_path_init(conn, &conn->c_path[i],
 217                                      is_outgoing);
 218                 conn->c_path[i].cp_index = i;
 219         }
 220         ret = trans->conn_alloc(conn, gfp);
 221         if (ret) {
 222                 kmem_cache_free(rds_conn_slab, conn);
 223                 conn = ERR_PTR(ret);
 224                 goto out;
 225         }
 226
 227         rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
 228           conn, &laddr, &faddr,
 229           trans->t_name ? trans->t_name : "[unknown]",
 230           is_outgoing ? "(outgoing)" : "");
 231
 232         /*
 233          * Since we ran without holding the conn lock, someone could
 234          * have created the same conn (either normal or passive) in the
 235          * interim. We check while holding the lock. If we won, we complete
 236          * init and return our conn. If we lost, we rollback and return the
 237          * other one.
 238          */
 239         spin_lock_irqsave(&rds_conn_lock, flags);
 240         if (parent) {
 241                 /* Creating passive conn */
 242                 if (parent->c_passive) {
 243                         trans->conn_free(conn->c_path[0].cp_transport_data);
 244                         kmem_cache_free(rds_conn_slab, conn);
 245                         conn = parent->c_passive;
 246                 } else {
 247                         parent->c_passive = conn;
 248                         rds_cong_add_conn(conn);
 249                         rds_conn_count++;
 250                 }
 251         } else {
 252                 /* Creating normal conn */
 253                 struct rds_connection *found;
 254
 255                 found = rds_conn_lookup(net, head, laddr, faddr, trans);
 256                 if (found) {
 257                         struct rds_conn_path *cp;
 258                         int i;
 259
 260                         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
 261                                 cp = &conn->c_path[i];
 262                                 /* The ->conn_alloc invocation may have
 263                                  * allocated resource for all paths, so all
 264                                  * of them may have to be freed here.
 265                                  */
 266                                 if (cp->cp_transport_data)
 267                                         trans->conn_free(cp->cp_transport_data);
 268                         }
 269                         kmem_cache_free(rds_conn_slab, conn);
 270                         conn = found;
 271                 } else {
 272                         conn->c_my_gen_num = rds_gen_num;
 273                         conn->c_peer_gen_num = 0;
 274                         hlist_add_head_rcu(&conn->c_hash_node, head);
 275                         rds_cong_add_conn(conn);
 276                         rds_conn_count++;
 277                 }
 278         }
 279         spin_unlock_irqrestore(&rds_conn_lock, flags);
 280
 281 out:
 282         return conn;
 283 }
 284
 285 struct rds_connection *rds_conn_create(struct net *net,
 286                                        __be32 laddr, __be32 faddr,
 287                                        struct rds_transport *trans, gfp_t gfp)
 288 {
 289         return __rds_conn_create(net, laddr, faddr, trans, gfp, 0);
 290 }
 291 EXPORT_SYMBOL_GPL(rds_conn_create);
 292
 293 struct rds_connection *rds_conn_create_outgoing(struct net *net,
 294                                                 __be32 laddr, __be32 faddr,
 295                                        struct rds_transport *trans, gfp_t gfp)
 296 {
 297         return __rds_conn_create(net, laddr, faddr, trans, gfp, 1);
 298 }
 299 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
 300
 301 void rds_conn_shutdown(struct rds_conn_path *cp)
 302 {
 303         struct rds_connection *conn = cp->cp_conn;
 304
 305         /* shut it down unless it's down already */
 306         if (!rds_conn_path_transition(cp, RDS_CONN_DOWN, RDS_CONN_DOWN)) {
 307                 /*
 308                  * Quiesce the connection mgmt handlers before we start tearing
 309                  * things down. We don't hold the mutex for the entire
 310                  * duration of the shutdown operation, else we may be
 311                  * deadlocking with the CM handler. Instead, the CM event
 312                  * handler is supposed to check for state DISCONNECTING
 313                  */
 314                 mutex_lock(&cp->cp_cm_lock);
 315                 if (!rds_conn_path_transition(cp, RDS_CONN_UP,
 316                                               RDS_CONN_DISCONNECTING) &&
 317                     !rds_conn_path_transition(cp, RDS_CONN_ERROR,
 318                                               RDS_CONN_DISCONNECTING)) {
 319                         rds_conn_path_error(cp,
 320                                             "shutdown called in state %d\n",
 321                                             atomic_read(&cp->cp_state));
 322                         mutex_unlock(&cp->cp_cm_lock);
 323                         return;
 324                 }
 325                 mutex_unlock(&cp->cp_cm_lock);
 326
 327                 wait_event(cp->cp_waitq,
 328                            !test_bit(RDS_IN_XMIT, &cp->cp_flags));
 329                 wait_event(cp->cp_waitq,
 330                            !test_bit(RDS_RECV_REFILL, &cp->cp_flags));
 331
 332                 conn->c_trans->conn_path_shutdown(cp);
 333                 rds_conn_path_reset(cp);
 334
 335                 if (!rds_conn_path_transition(cp, RDS_CONN_DISCONNECTING,
 336                                               RDS_CONN_DOWN) &&
 337                     !rds_conn_path_transition(cp, RDS_CONN_ERROR,
 338                                               RDS_CONN_DOWN)) {
 339                         /* This can happen - eg when we're in the middle of tearing
 340                          * down the connection, and someone unloads the rds module.
 341                          * Quite reproducible with loopback connections.
 342                          * Mostly harmless.
 343                          *
 344                          * Note that this also happens with rds-tcp because
 345                          * we could have triggered rds_conn_path_drop in irq
 346                          * mode from rds_tcp_state change on the receipt of
 347                          * a FIN, thus we need to recheck for RDS_CONN_ERROR
 348                          * here.
 349                          */
 350                         rds_conn_path_error(cp, "%s: failed to transition "
 351                                             "to state DOWN, current state "
 352                                             "is %d\n", __func__,
 353                                             atomic_read(&cp->cp_state));
 354                         return;
 355                 }
 356         }
 357
 358         /* Then reconnect if it's still live.
 359          * The passive side of an IB loopback connection is never added
 360          * to the conn hash, so we never trigger a reconnect on this
 361          * conn - the reconnect is always triggered by the active peer. */
 362         cancel_delayed_work_sync(&cp->cp_conn_w);
 363         rcu_read_lock();
 364         if (!hlist_unhashed(&conn->c_hash_node)) {
 365                 rcu_read_unlock();
 366                 rds_queue_reconnect(cp);
 367         } else {
 368                 rcu_read_unlock();
 369         }
 370 }
 371
 372 /* destroy a single rds_conn_path. rds_conn_destroy() iterates over
 373  * all paths using rds_conn_path_destroy()
 374  */
 375 static void rds_conn_path_destroy(struct rds_conn_path *cp)
 376 {
 377         struct rds_message *rm, *rtmp;
 378
 379         if (!cp->cp_transport_data)
 380                 return;
 381
 382         rds_conn_path_drop(cp);
 383         flush_work(&cp->cp_down_w);
 384
 385         /* make sure lingering queued work won't try to ref the conn */
 386         cancel_delayed_work_sync(&cp->cp_send_w);
 387         cancel_delayed_work_sync(&cp->cp_recv_w);
 388
 389         /* tear down queued messages */
 390         list_for_each_entry_safe(rm, rtmp,
 391                                  &cp->cp_send_queue,
 392                                  m_conn_item) {
 393                 list_del_init(&rm->m_conn_item);
 394                 BUG_ON(!list_empty(&rm->m_sock_item));
 395                 rds_message_put(rm);
 396         }
 397         if (cp->cp_xmit_rm)
 398                 rds_message_put(cp->cp_xmit_rm);
 399
 400         cp->cp_conn->c_trans->conn_free(cp->cp_transport_data);
 401 }
 402
 403 /*
 404  * Stop and free a connection.
 405  *
 406  * This can only be used in very limited circumstances.  It assumes that once
 407  * the conn has been shutdown that no one else is referencing the connection.
 408  * We can only ensure this in the rmmod path in the current code.
 409  */
 410 void rds_conn_destroy(struct rds_connection *conn)
 411 {
 412         unsigned long flags;
 413         int i;
 414         struct rds_conn_path *cp;
 415
 416         rdsdebug("freeing conn %p for %pI4 -> "
 417                  "%pI4\n", conn, &conn->c_laddr,
 418                  &conn->c_faddr);
 419
 420         /* Ensure conn will not be scheduled for reconnect */
 421         spin_lock_irq(&rds_conn_lock);
 422         hlist_del_init_rcu(&conn->c_hash_node);
 423         spin_unlock_irq(&rds_conn_lock);
 424         synchronize_rcu();
 425
 426         /* shut the connection down */
 427         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
 428                 cp = &conn->c_path[i];
 429                 rds_conn_path_destroy(cp);
 430                 BUG_ON(!list_empty(&cp->cp_retrans));
 431         }
 432
 433         /*
 434          * The congestion maps aren't freed up here.  They're
 435          * freed by rds_cong_exit() after all the connections
 436          * have been freed.
 437          */
 438         rds_cong_remove_conn(conn);
 439
 440         put_net(conn->c_net);
 441         kmem_cache_free(rds_conn_slab, conn);
 442
 443         spin_lock_irqsave(&rds_conn_lock, flags);
 444         rds_conn_count--;
 445         spin_unlock_irqrestore(&rds_conn_lock, flags);
 446 }
 447 EXPORT_SYMBOL_GPL(rds_conn_destroy);
 448
 449 static void rds_conn_message_info(struct socket *sock, unsigned int len,
 450                                   struct rds_info_iterator *iter,
 451                                   struct rds_info_lengths *lens,
 452                                   int want_send)
 453 {
 454         struct hlist_head *head;
 455         struct list_head *list;
 456         struct rds_connection *conn;
 457         struct rds_message *rm;
 458         unsigned int total = 0;
 459         unsigned long flags;
 460         size_t i;
 461         int j;
 462
 463         len /= sizeof(struct rds_info_message);
 464
 465         rcu_read_lock();
 466
 467         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 468              i++, head++) {
 469                 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
 470                         struct rds_conn_path *cp;
 471
 472                         for (j = 0; j < RDS_MPATH_WORKERS; j++) {
 473                                 cp = &conn->c_path[j];
 474                                 if (want_send)
 475                                         list = &cp->cp_send_queue;
 476                                 else
 477                                         list = &cp->cp_retrans;
 478
 479                                 spin_lock_irqsave(&cp->cp_lock, flags);
 480
 481                                 /* XXX too lazy to maintain counts.. */
 482                                 list_for_each_entry(rm, list, m_conn_item) {
 483                                         total++;
 484                                         if (total <= len)
 485                                                 rds_inc_info_copy(&rm->m_inc,
 486                                                                   iter,
 487                                                                   conn->c_laddr,
 488                                                                   conn->c_faddr,
 489                                                                   0);
 490                                 }
 491
 492                                 spin_unlock_irqrestore(&cp->cp_lock, flags);
 493                                 if (!conn->c_trans->t_mp_capable)
 494                                         break;
 495                         }
 496                 }
 497         }
 498         rcu_read_unlock();
 499
 500         lens->nr = total;
 501         lens->each = sizeof(struct rds_info_message);
 502 }
 503
 504 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
 505                                        struct rds_info_iterator *iter,
 506                                        struct rds_info_lengths *lens)
 507 {
 508         rds_conn_message_info(sock, len, iter, lens, 1);
 509 }
 510
 511 static void rds_conn_message_info_retrans(struct socket *sock,
 512                                           unsigned int len,
 513                                           struct rds_info_iterator *iter,
 514                                           struct rds_info_lengths *lens)
 515 {
 516         rds_conn_message_info(sock, len, iter, lens, 0);
 517 }
 518
 519 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
 520                           struct rds_info_iterator *iter,
 521                           struct rds_info_lengths *lens,
 522                           int (*visitor)(struct rds_connection *, void *),
 523                           size_t item_len)
 524 {
 525         uint64_t buffer[(item_len + 7) / 8];
 526         struct hlist_head *head;
 527         struct rds_connection *conn;
 528         size_t i;
 529
 530         rcu_read_lock();
 531
 532         lens->nr = 0;
 533         lens->each = item_len;
 534
 535         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 536              i++, head++) {
 537                 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
 538
 539                         /* XXX no c_lock usage.. */
 540                         if (!visitor(conn, buffer))
 541                                 continue;
 542
 543                         /* We copy as much as we can fit in the buffer,
 544                          * but we count all items so that the caller
 545                          * can resize the buffer. */
 546                         if (len >= item_len) {
 547                                 rds_info_copy(iter, buffer, item_len);
 548                                 len -= item_len;
 549                         }
 550                         lens->nr++;
 551                 }
 552         }
 553         rcu_read_unlock();
 554 }
 555 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
 556
 557 static void rds_walk_conn_path_info(struct socket *sock, unsigned int len,
 558                                     struct rds_info_iterator *iter,
 559                                     struct rds_info_lengths *lens,
 560                                     int (*visitor)(struct rds_conn_path *, void *),
 561                                     size_t item_len)
 562 {
 563         u64  buffer[(item_len + 7) / 8];
 564         struct hlist_head *head;
 565         struct rds_connection *conn;
 566         size_t i;
 567         int j;
 568
 569         rcu_read_lock();
 570
 571         lens->nr = 0;
 572         lens->each = item_len;
 573
 574         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 575              i++, head++) {
 576                 hlist_for_each_entry_rcu(conn, head, c_hash_node) {
 577                         struct rds_conn_path *cp;
 578
 579                         for (j = 0; j < RDS_MPATH_WORKERS; j++) {
 580                                 cp = &conn->c_path[j];
 581
 582                                 /* XXX no cp_lock usage.. */
 583                                 if (!visitor(cp, buffer))
 584                                         continue;
 585                                 if (!conn->c_trans->t_mp_capable)
 586                                         break;
 587                         }
 588
 589                         /* We copy as much as we can fit in the buffer,
 590                          * but we count all items so that the caller
 591                          * can resize the buffer.
 592                          */
 593                         if (len >= item_len) {
 594                                 rds_info_copy(iter, buffer, item_len);
 595                                 len -= item_len;
 596                         }
 597                         lens->nr++;
 598                 }
 599         }
 600         rcu_read_unlock();
 601 }
 602
 603 static int rds_conn_info_visitor(struct rds_conn_path *cp, void *buffer)
 604 {
 605         struct rds_info_connection *cinfo = buffer;
 606
 607         cinfo->next_tx_seq = cp->cp_next_tx_seq;
 608         cinfo->next_rx_seq = cp->cp_next_rx_seq;
 609         cinfo->laddr = cp->cp_conn->c_laddr;
 610         cinfo->faddr = cp->cp_conn->c_faddr;
 611         strncpy(cinfo->transport, cp->cp_conn->c_trans->t_name,
 612                 sizeof(cinfo->transport));
 613         cinfo->flags = 0;
 614
 615         rds_conn_info_set(cinfo->flags, test_bit(RDS_IN_XMIT, &cp->cp_flags),
 616                           SENDING);
 617         /* XXX Future: return the state rather than these funky bits */
 618         rds_conn_info_set(cinfo->flags,
 619                           atomic_read(&cp->cp_state) == RDS_CONN_CONNECTING,
 620                           CONNECTING);
 621         rds_conn_info_set(cinfo->flags,
 622                           atomic_read(&cp->cp_state) == RDS_CONN_UP,
 623                           CONNECTED);
 624         return 1;
 625 }
 626
 627 static void rds_conn_info(struct socket *sock, unsigned int len,
 628                           struct rds_info_iterator *iter,
 629                           struct rds_info_lengths *lens)
 630 {
 631         rds_walk_conn_path_info(sock, len, iter, lens,
 632                                 rds_conn_info_visitor,
 633                                 sizeof(struct rds_info_connection));
 634 }
 635
 636 int rds_conn_init(void)
 637 {
 638         rds_conn_slab = kmem_cache_create("rds_connection",
 639                                           sizeof(struct rds_connection),
 640                                           0, 0, NULL);
 641         if (!rds_conn_slab)
 642                 return -ENOMEM;
 643
 644         rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 645         rds_info_register_func(RDS_INFO_SEND_MESSAGES,
 646                                rds_conn_message_info_send);
 647         rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
 648                                rds_conn_message_info_retrans);
 649
 650         return 0;
 651 }
 652
 653 void rds_conn_exit(void)
 654 {
 655         rds_loop_exit();
 656
 657         WARN_ON(!hlist_empty(rds_conn_hash));
 658
 659         kmem_cache_destroy(rds_conn_slab);
 660
 661         rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 662         rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
 663                                  rds_conn_message_info_send);
 664         rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
 665                                  rds_conn_message_info_retrans);
 666 }
 667
 668 /*
 669  * Force a disconnect
 670  */
 671 void rds_conn_path_drop(struct rds_conn_path *cp)
 672 {
 673         atomic_set(&cp->cp_state, RDS_CONN_ERROR);
 674         queue_work(rds_wq, &cp->cp_down_w);
 675 }
 676 EXPORT_SYMBOL_GPL(rds_conn_path_drop);
 677
 678 void rds_conn_drop(struct rds_connection *conn)
 679 {
 680         WARN_ON(conn->c_trans->t_mp_capable);
 681         rds_conn_path_drop(&conn->c_path[0]);
 682 }
 683 EXPORT_SYMBOL_GPL(rds_conn_drop);
 684
 685 /*
 686  * If the connection is down, trigger a connect. We may have scheduled a
 687  * delayed reconnect however - in this case we should not interfere.
 688  */
 689 void rds_conn_path_connect_if_down(struct rds_conn_path *cp)
 690 {
 691         if (rds_conn_path_state(cp) == RDS_CONN_DOWN &&
 692             !test_and_set_bit(RDS_RECONNECT_PENDING, &cp->cp_flags))
 693                 queue_delayed_work(rds_wq, &cp->cp_conn_w, 0);
 694 }
 695 EXPORT_SYMBOL_GPL(rds_conn_path_connect_if_down);
 696
 697 void rds_conn_connect_if_down(struct rds_connection *conn)
 698 {
 699         WARN_ON(conn->c_trans->t_mp_capable);
 700         rds_conn_path_connect_if_down(&conn->c_path[0]);
 701 }
 702 EXPORT_SYMBOL_GPL(rds_conn_connect_if_down);
 703
 704 void
 705 __rds_conn_path_error(struct rds_conn_path *cp, const char *fmt, ...)
 706 {
 707         va_list ap;
 708
 709         va_start(ap, fmt);
 710         vprintk(fmt, ap);
 711         va_end(ap);
 712
 713         rds_conn_path_drop(cp);
 714 }