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 <net/inet_hashtables.h>
  36
  37 #include "rds.h"
  38 #include "loop.h"
  39 #include "rdma.h"
  40
  41 #define RDS_CONNECTION_HASH_BITS 12
  42 #define RDS_CONNECTION_HASH_ENTRIES (1 << RDS_CONNECTION_HASH_BITS)
  43 #define RDS_CONNECTION_HASH_MASK (RDS_CONNECTION_HASH_ENTRIES - 1)
  44
  45 /* converting this to RCU is a chore for another day.. */
  46 static DEFINE_SPINLOCK(rds_conn_lock);
  47 static unsigned long rds_conn_count;
  48 static struct hlist_head rds_conn_hash[RDS_CONNECTION_HASH_ENTRIES];
  49 static struct kmem_cache *rds_conn_slab;
  50
  51 static struct hlist_head *rds_conn_bucket(__be32 laddr, __be32 faddr)
  52 {
  53         /* Pass NULL, don't need struct net for hash */
  54         unsigned long hash = inet_ehashfn(NULL,
  55                                           be32_to_cpu(laddr), 0,
  56                                           be32_to_cpu(faddr), 0);
  57         return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
  58 }
  59
  60 #define rds_conn_info_set(var, test, suffix) do {               \
  61         if (test)                                               \
  62                 var |= RDS_INFO_CONNECTION_FLAG_##suffix;       \
  63 } while (0)
  64
  65 static inline int rds_conn_is_sending(struct rds_connection *conn)
  66 {
  67         int ret = 0;
  68
  69         if (!mutex_trylock(&conn->c_send_lock))
  70                 ret = 1;
  71         else
  72                 mutex_unlock(&conn->c_send_lock);
  73
  74         return ret;
  75 }
  76
  77 static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
  78                                               __be32 laddr, __be32 faddr,
  79                                               struct rds_transport *trans)
  80 {
  81         struct rds_connection *conn, *ret = NULL;
  82         struct hlist_node *pos;
  83
  84         hlist_for_each_entry(conn, pos, head, c_hash_node) {
  85                 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
  86                                 conn->c_trans == trans) {
  87                         ret = conn;
  88                         break;
  89                 }
  90         }
  91         rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
  92                  &laddr, &faddr);
  93         return ret;
  94 }
  95
  96 /*
  97  * This is called by transports as they're bringing down a connection.
  98  * It clears partial message state so that the transport can start sending
  99  * and receiving over this connection again in the future.  It is up to
 100  * the transport to have serialized this call with its send and recv.
 101  */
 102 void rds_conn_reset(struct rds_connection *conn)
 103 {
 104         rdsdebug("connection %pI4 to %pI4 reset\n",
 105           &conn->c_laddr, &conn->c_faddr);
 106
 107         rds_stats_inc(s_conn_reset);
 108         rds_send_reset(conn);
 109         conn->c_flags = 0;
 110
 111         /* Do not clear next_rx_seq here, else we cannot distinguish
 112          * retransmitted packets from new packets, and will hand all
 113          * of them to the application. That is not consistent with the
 114          * reliability guarantees of RDS. */
 115 }
 116
 117 /*
 118  * There is only every one 'conn' for a given pair of addresses in the
 119  * system at a time.  They contain messages to be retransmitted and so
 120  * span the lifetime of the actual underlying transport connections.
 121  *
 122  * For now they are not garbage collected once they're created.  They
 123  * are torn down as the module is removed, if ever.
 124  */
 125 static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
 126                                        struct rds_transport *trans, gfp_t gfp,
 127                                        int is_outgoing)
 128 {
 129         struct rds_connection *conn, *parent = NULL;
 130         struct hlist_head *head = rds_conn_bucket(laddr, faddr);
 131         unsigned long flags;
 132         int ret;
 133
 134         spin_lock_irqsave(&rds_conn_lock, flags);
 135         conn = rds_conn_lookup(head, laddr, faddr, trans);
 136         if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
 137             !is_outgoing) {
 138                 /* This is a looped back IB connection, and we're
 139                  * called by the code handling the incoming connect.
 140                  * We need a second connection object into which we
 141                  * can stick the other QP. */
 142                 parent = conn;
 143                 conn = parent->c_passive;
 144         }
 145         spin_unlock_irqrestore(&rds_conn_lock, flags);
 146         if (conn)
 147                 goto out;
 148
 149         conn = kmem_cache_zalloc(rds_conn_slab, gfp);
 150         if (conn == NULL) {
 151                 conn = ERR_PTR(-ENOMEM);
 152                 goto out;
 153         }
 154
 155         INIT_HLIST_NODE(&conn->c_hash_node);
 156         conn->c_laddr = laddr;
 157         conn->c_faddr = faddr;
 158         spin_lock_init(&conn->c_lock);
 159         conn->c_next_tx_seq = 1;
 160
 161         mutex_init(&conn->c_send_lock);
 162         INIT_LIST_HEAD(&conn->c_send_queue);
 163         INIT_LIST_HEAD(&conn->c_retrans);
 164
 165         ret = rds_cong_get_maps(conn);
 166         if (ret) {
 167                 kmem_cache_free(rds_conn_slab, conn);
 168                 conn = ERR_PTR(ret);
 169                 goto out;
 170         }
 171
 172         /*
 173          * This is where a connection becomes loopback.  If *any* RDS sockets
 174          * can bind to the destination address then we'd rather the messages
 175          * flow through loopback rather than either transport.
 176          */
 177         if (rds_trans_get_preferred(faddr)) {
 178                 conn->c_loopback = 1;
 179                 if (is_outgoing && trans->t_prefer_loopback) {
 180                         /* "outgoing" connection - and the transport
 181                          * says it wants the connection handled by the
 182                          * loopback transport. This is what TCP does.
 183                          */
 184                         trans = &rds_loop_transport;
 185                 }
 186         }
 187
 188         conn->c_trans = trans;
 189
 190         ret = trans->conn_alloc(conn, gfp);
 191         if (ret) {
 192                 kmem_cache_free(rds_conn_slab, conn);
 193                 conn = ERR_PTR(ret);
 194                 goto out;
 195         }
 196
 197         atomic_set(&conn->c_state, RDS_CONN_DOWN);
 198         conn->c_reconnect_jiffies = 0;
 199         INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
 200         INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
 201         INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
 202         INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
 203         mutex_init(&conn->c_cm_lock);
 204         conn->c_flags = 0;
 205
 206         rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
 207           conn, &laddr, &faddr,
 208           trans->t_name ? trans->t_name : "[unknown]",
 209           is_outgoing ? "(outgoing)" : "");
 210
 211         /*
 212          * Since we ran without holding the conn lock, someone could
 213          * have created the same conn (either normal or passive) in the
 214          * interim. We check while holding the lock. If we won, we complete
 215          * init and return our conn. If we lost, we rollback and return the
 216          * other one.
 217          */
 218         spin_lock_irqsave(&rds_conn_lock, flags);
 219         if (parent) {
 220                 /* Creating passive conn */
 221                 if (parent->c_passive) {
 222                         trans->conn_free(conn->c_transport_data);
 223                         kmem_cache_free(rds_conn_slab, conn);
 224                         conn = parent->c_passive;
 225                 } else {
 226                         parent->c_passive = conn;
 227                         rds_cong_add_conn(conn);
 228                         rds_conn_count++;
 229                 }
 230         } else {
 231                 /* Creating normal conn */
 232                 struct rds_connection *found;
 233
 234                 found = rds_conn_lookup(head, laddr, faddr, trans);
 235                 if (found) {
 236                         trans->conn_free(conn->c_transport_data);
 237                         kmem_cache_free(rds_conn_slab, conn);
 238                         conn = found;
 239                 } else {
 240                         hlist_add_head(&conn->c_hash_node, head);
 241                         rds_cong_add_conn(conn);
 242                         rds_conn_count++;
 243                 }
 244         }
 245         spin_unlock_irqrestore(&rds_conn_lock, flags);
 246
 247 out:
 248         return conn;
 249 }
 250
 251 struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
 252                                        struct rds_transport *trans, gfp_t gfp)
 253 {
 254         return __rds_conn_create(laddr, faddr, trans, gfp, 0);
 255 }
 256 EXPORT_SYMBOL_GPL(rds_conn_create);
 257
 258 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
 259                                        struct rds_transport *trans, gfp_t gfp)
 260 {
 261         return __rds_conn_create(laddr, faddr, trans, gfp, 1);
 262 }
 263 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
 264
 265 void rds_conn_destroy(struct rds_connection *conn)
 266 {
 267         struct rds_message *rm, *rtmp;
 268
 269         rdsdebug("freeing conn %p for %pI4 -> "
 270                  "%pI4\n", conn, &conn->c_laddr,
 271                  &conn->c_faddr);
 272
 273         hlist_del_init(&conn->c_hash_node);
 274
 275         /* wait for the rds thread to shut it down */
 276         atomic_set(&conn->c_state, RDS_CONN_ERROR);
 277         cancel_delayed_work(&conn->c_conn_w);
 278         queue_work(rds_wq, &conn->c_down_w);
 279         flush_workqueue(rds_wq);
 280
 281         /* tear down queued messages */
 282         list_for_each_entry_safe(rm, rtmp,
 283                                  &conn->c_send_queue,
 284                                  m_conn_item) {
 285                 list_del_init(&rm->m_conn_item);
 286                 BUG_ON(!list_empty(&rm->m_sock_item));
 287                 rds_message_put(rm);
 288         }
 289         if (conn->c_xmit_rm)
 290                 rds_message_put(conn->c_xmit_rm);
 291
 292         conn->c_trans->conn_free(conn->c_transport_data);
 293
 294         /*
 295          * The congestion maps aren't freed up here.  They're
 296          * freed by rds_cong_exit() after all the connections
 297          * have been freed.
 298          */
 299         rds_cong_remove_conn(conn);
 300
 301         BUG_ON(!list_empty(&conn->c_retrans));
 302         kmem_cache_free(rds_conn_slab, conn);
 303
 304         rds_conn_count--;
 305 }
 306 EXPORT_SYMBOL_GPL(rds_conn_destroy);
 307
 308 static void rds_conn_message_info(struct socket *sock, unsigned int len,
 309                                   struct rds_info_iterator *iter,
 310                                   struct rds_info_lengths *lens,
 311                                   int want_send)
 312 {
 313         struct hlist_head *head;
 314         struct hlist_node *pos;
 315         struct list_head *list;
 316         struct rds_connection *conn;
 317         struct rds_message *rm;
 318         unsigned long flags;
 319         unsigned int total = 0;
 320         size_t i;
 321
 322         len /= sizeof(struct rds_info_message);
 323
 324         spin_lock_irqsave(&rds_conn_lock, flags);
 325
 326         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 327              i++, head++) {
 328                 hlist_for_each_entry(conn, pos, head, c_hash_node) {
 329                         if (want_send)
 330                                 list = &conn->c_send_queue;
 331                         else
 332                                 list = &conn->c_retrans;
 333
 334                         spin_lock(&conn->c_lock);
 335
 336                         /* XXX too lazy to maintain counts.. */
 337                         list_for_each_entry(rm, list, m_conn_item) {
 338                                 total++;
 339                                 if (total <= len)
 340                                         rds_inc_info_copy(&rm->m_inc, iter,
 341                                                           conn->c_laddr,
 342                                                           conn->c_faddr, 0);
 343                         }
 344
 345                         spin_unlock(&conn->c_lock);
 346                 }
 347         }
 348
 349         spin_unlock_irqrestore(&rds_conn_lock, flags);
 350
 351         lens->nr = total;
 352         lens->each = sizeof(struct rds_info_message);
 353 }
 354
 355 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
 356                                        struct rds_info_iterator *iter,
 357                                        struct rds_info_lengths *lens)
 358 {
 359         rds_conn_message_info(sock, len, iter, lens, 1);
 360 }
 361
 362 static void rds_conn_message_info_retrans(struct socket *sock,
 363                                           unsigned int len,
 364                                           struct rds_info_iterator *iter,
 365                                           struct rds_info_lengths *lens)
 366 {
 367         rds_conn_message_info(sock, len, iter, lens, 0);
 368 }
 369
 370 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
 371                           struct rds_info_iterator *iter,
 372                           struct rds_info_lengths *lens,
 373                           int (*visitor)(struct rds_connection *, void *),
 374                           size_t item_len)
 375 {
 376         uint64_t buffer[(item_len + 7) / 8];
 377         struct hlist_head *head;
 378         struct hlist_node *pos;
 379         struct hlist_node *tmp;
 380         struct rds_connection *conn;
 381         unsigned long flags;
 382         size_t i;
 383
 384         spin_lock_irqsave(&rds_conn_lock, flags);
 385
 386         lens->nr = 0;
 387         lens->each = item_len;
 388
 389         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 390              i++, head++) {
 391                 hlist_for_each_entry_safe(conn, pos, tmp, head, c_hash_node) {
 392
 393                         /* XXX no c_lock usage.. */
 394                         if (!visitor(conn, buffer))
 395                                 continue;
 396
 397                         /* We copy as much as we can fit in the buffer,
 398                          * but we count all items so that the caller
 399                          * can resize the buffer. */
 400                         if (len >= item_len) {
 401                                 rds_info_copy(iter, buffer, item_len);
 402                                 len -= item_len;
 403                         }
 404                         lens->nr++;
 405                 }
 406         }
 407
 408         spin_unlock_irqrestore(&rds_conn_lock, flags);
 409 }
 410 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
 411
 412 static int rds_conn_info_visitor(struct rds_connection *conn,
 413                                   void *buffer)
 414 {
 415         struct rds_info_connection *cinfo = buffer;
 416
 417         cinfo->next_tx_seq = conn->c_next_tx_seq;
 418         cinfo->next_rx_seq = conn->c_next_rx_seq;
 419         cinfo->laddr = conn->c_laddr;
 420         cinfo->faddr = conn->c_faddr;
 421         strncpy(cinfo->transport, conn->c_trans->t_name,
 422                 sizeof(cinfo->transport));
 423         cinfo->flags = 0;
 424
 425         rds_conn_info_set(cinfo->flags,
 426                           rds_conn_is_sending(conn), SENDING);
 427         /* XXX Future: return the state rather than these funky bits */
 428         rds_conn_info_set(cinfo->flags,
 429                           atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
 430                           CONNECTING);
 431         rds_conn_info_set(cinfo->flags,
 432                           atomic_read(&conn->c_state) == RDS_CONN_UP,
 433                           CONNECTED);
 434         return 1;
 435 }
 436
 437 static void rds_conn_info(struct socket *sock, unsigned int len,
 438                           struct rds_info_iterator *iter,
 439                           struct rds_info_lengths *lens)
 440 {
 441         rds_for_each_conn_info(sock, len, iter, lens,
 442                                 rds_conn_info_visitor,
 443                                 sizeof(struct rds_info_connection));
 444 }
 445
 446 int __init rds_conn_init(void)
 447 {
 448         rds_conn_slab = kmem_cache_create("rds_connection",
 449                                           sizeof(struct rds_connection),
 450                                           0, 0, NULL);
 451         if (rds_conn_slab == NULL)
 452                 return -ENOMEM;
 453
 454         rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 455         rds_info_register_func(RDS_INFO_SEND_MESSAGES,
 456                                rds_conn_message_info_send);
 457         rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
 458                                rds_conn_message_info_retrans);
 459
 460         return 0;
 461 }
 462
 463 void rds_conn_exit(void)
 464 {
 465         rds_loop_exit();
 466
 467         WARN_ON(!hlist_empty(rds_conn_hash));
 468
 469         kmem_cache_destroy(rds_conn_slab);
 470
 471         rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 472         rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
 473                                  rds_conn_message_info_send);
 474         rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
 475                                  rds_conn_message_info_retrans);
 476 }
 477
 478 /*
 479  * Force a disconnect
 480  */
 481 void rds_conn_drop(struct rds_connection *conn)
 482 {
 483         atomic_set(&conn->c_state, RDS_CONN_ERROR);
 484         queue_work(rds_wq, &conn->c_down_w);
 485 }
 486 EXPORT_SYMBOL_GPL(rds_conn_drop);
 487
 488 /*
 489  * An error occurred on the connection
 490  */
 491 void
 492 __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
 493 {
 494         va_list ap;
 495
 496         va_start(ap, fmt);
 497         vprintk(fmt, ap);
 498         va_end(ap);
 499
 500         rds_conn_drop(conn);
 501 }