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
 137          && conn->c_loopback
 138          && conn->c_trans != &rds_loop_transport
 139          && !is_outgoing) {
 140                 /* This is a looped back IB connection, and we're
 141                  * called by the code handling the incoming connect.
 142                  * We need a second connection object into which we
 143                  * can stick the other QP. */
 144                 parent = conn;
 145                 conn = parent->c_passive;
 146         }
 147         spin_unlock_irqrestore(&rds_conn_lock, flags);
 148         if (conn)
 149                 goto out;
 150
 151         conn = kmem_cache_zalloc(rds_conn_slab, gfp);
 152         if (conn == NULL) {
 153                 conn = ERR_PTR(-ENOMEM);
 154                 goto out;
 155         }
 156
 157         INIT_HLIST_NODE(&conn->c_hash_node);
 158         conn->c_laddr = laddr;
 159         conn->c_faddr = faddr;
 160         spin_lock_init(&conn->c_lock);
 161         conn->c_next_tx_seq = 1;
 162
 163         mutex_init(&conn->c_send_lock);
 164         INIT_LIST_HEAD(&conn->c_send_queue);
 165         INIT_LIST_HEAD(&conn->c_retrans);
 166
 167         ret = rds_cong_get_maps(conn);
 168         if (ret) {
 169                 kmem_cache_free(rds_conn_slab, conn);
 170                 conn = ERR_PTR(ret);
 171                 goto out;
 172         }
 173
 174         /*
 175          * This is where a connection becomes loopback.  If *any* RDS sockets
 176          * can bind to the destination address then we'd rather the messages
 177          * flow through loopback rather than either transport.
 178          */
 179         if (rds_trans_get_preferred(faddr)) {
 180                 conn->c_loopback = 1;
 181                 if (is_outgoing && trans->t_prefer_loopback) {
 182                         /* "outgoing" connection - and the transport
 183                          * says it wants the connection handled by the
 184                          * loopback transport. This is what TCP does.
 185                          */
 186                         trans = &rds_loop_transport;
 187                 }
 188         }
 189
 190         conn->c_trans = trans;
 191
 192         ret = trans->conn_alloc(conn, gfp);
 193         if (ret) {
 194                 kmem_cache_free(rds_conn_slab, conn);
 195                 conn = ERR_PTR(ret);
 196                 goto out;
 197         }
 198
 199         atomic_set(&conn->c_state, RDS_CONN_DOWN);
 200         conn->c_reconnect_jiffies = 0;
 201         INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
 202         INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
 203         INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
 204         INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
 205         mutex_init(&conn->c_cm_lock);
 206         conn->c_flags = 0;
 207
 208         rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
 209           conn, &laddr, &faddr,
 210           trans->t_name ? trans->t_name : "[unknown]",
 211           is_outgoing ? "(outgoing)" : "");
 212
 213         /*
 214          * Since we ran without holding the conn lock, someone could
 215          * have created the same conn (either normal or passive) in the
 216          * interim. We check while holding the lock. If we won, we complete
 217          * init and return our conn. If we lost, we rollback and return the
 218          * other one.
 219          */
 220         spin_lock_irqsave(&rds_conn_lock, flags);
 221         if (parent) {
 222                 /* Creating passive conn */
 223                 if (parent->c_passive) {
 224                         trans->conn_free(conn->c_transport_data);
 225                         kmem_cache_free(rds_conn_slab, conn);
 226                         conn = parent->c_passive;
 227                 } else {
 228                         parent->c_passive = conn;
 229                         rds_cong_add_conn(conn);
 230                         rds_conn_count++;
 231                 }
 232         } else {
 233                 /* Creating normal conn */
 234                 struct rds_connection *found;
 235
 236                 found = rds_conn_lookup(head, laddr, faddr, trans);
 237                 if (found) {
 238                         trans->conn_free(conn->c_transport_data);
 239                         kmem_cache_free(rds_conn_slab, conn);
 240                         conn = found;
 241                 } else {
 242                         hlist_add_head(&conn->c_hash_node, head);
 243                         rds_cong_add_conn(conn);
 244                         rds_conn_count++;
 245                 }
 246         }
 247         spin_unlock_irqrestore(&rds_conn_lock, flags);
 248
 249 out:
 250         return conn;
 251 }
 252
 253 struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
 254                                        struct rds_transport *trans, gfp_t gfp)
 255 {
 256         return __rds_conn_create(laddr, faddr, trans, gfp, 0);
 257 }
 258 EXPORT_SYMBOL_GPL(rds_conn_create);
 259
 260 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
 261                                        struct rds_transport *trans, gfp_t gfp)
 262 {
 263         return __rds_conn_create(laddr, faddr, trans, gfp, 1);
 264 }
 265 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
 266
 267 void rds_conn_destroy(struct rds_connection *conn)
 268 {
 269         struct rds_message *rm, *rtmp;
 270
 271         rdsdebug("freeing conn %p for %pI4 -> "
 272                  "%pI4\n", conn, &conn->c_laddr,
 273                  &conn->c_faddr);
 274
 275         hlist_del_init(&conn->c_hash_node);
 276
 277         /* wait for the rds thread to shut it down */
 278         atomic_set(&conn->c_state, RDS_CONN_ERROR);
 279         cancel_delayed_work(&conn->c_conn_w);
 280         queue_work(rds_wq, &conn->c_down_w);
 281         flush_workqueue(rds_wq);
 282
 283         /* tear down queued messages */
 284         list_for_each_entry_safe(rm, rtmp,
 285                                  &conn->c_send_queue,
 286                                  m_conn_item) {
 287                 list_del_init(&rm->m_conn_item);
 288                 BUG_ON(!list_empty(&rm->m_sock_item));
 289                 rds_message_put(rm);
 290         }
 291         if (conn->c_xmit_rm)
 292                 rds_message_put(conn->c_xmit_rm);
 293
 294         conn->c_trans->conn_free(conn->c_transport_data);
 295
 296         /*
 297          * The congestion maps aren't freed up here.  They're
 298          * freed by rds_cong_exit() after all the connections
 299          * have been freed.
 300          */
 301         rds_cong_remove_conn(conn);
 302
 303         BUG_ON(!list_empty(&conn->c_retrans));
 304         kmem_cache_free(rds_conn_slab, conn);
 305
 306         rds_conn_count--;
 307 }
 308 EXPORT_SYMBOL_GPL(rds_conn_destroy);
 309
 310 static void rds_conn_message_info(struct socket *sock, unsigned int len,
 311                                   struct rds_info_iterator *iter,
 312                                   struct rds_info_lengths *lens,
 313                                   int want_send)
 314 {
 315         struct hlist_head *head;
 316         struct hlist_node *pos;
 317         struct list_head *list;
 318         struct rds_connection *conn;
 319         struct rds_message *rm;
 320         unsigned long flags;
 321         unsigned int total = 0;
 322         size_t i;
 323
 324         len /= sizeof(struct rds_info_message);
 325
 326         spin_lock_irqsave(&rds_conn_lock, flags);
 327
 328         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 329              i++, head++) {
 330                 hlist_for_each_entry(conn, pos, head, c_hash_node) {
 331                         if (want_send)
 332                                 list = &conn->c_send_queue;
 333                         else
 334                                 list = &conn->c_retrans;
 335
 336                         spin_lock(&conn->c_lock);
 337
 338                         /* XXX too lazy to maintain counts.. */
 339                         list_for_each_entry(rm, list, m_conn_item) {
 340                                 total++;
 341                                 if (total <= len)
 342                                         rds_inc_info_copy(&rm->m_inc, iter,
 343                                                           conn->c_laddr,
 344                                                           conn->c_faddr, 0);
 345                         }
 346
 347                         spin_unlock(&conn->c_lock);
 348                 }
 349         }
 350
 351         spin_unlock_irqrestore(&rds_conn_lock, flags);
 352
 353         lens->nr = total;
 354         lens->each = sizeof(struct rds_info_message);
 355 }
 356
 357 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
 358                                        struct rds_info_iterator *iter,
 359                                        struct rds_info_lengths *lens)
 360 {
 361         rds_conn_message_info(sock, len, iter, lens, 1);
 362 }
 363
 364 static void rds_conn_message_info_retrans(struct socket *sock,
 365                                           unsigned int len,
 366                                           struct rds_info_iterator *iter,
 367                                           struct rds_info_lengths *lens)
 368 {
 369         rds_conn_message_info(sock, len, iter, lens, 0);
 370 }
 371
 372 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
 373                           struct rds_info_iterator *iter,
 374                           struct rds_info_lengths *lens,
 375                           int (*visitor)(struct rds_connection *, void *),
 376                           size_t item_len)
 377 {
 378         uint64_t buffer[(item_len + 7) / 8];
 379         struct hlist_head *head;
 380         struct hlist_node *pos;
 381         struct hlist_node *tmp;
 382         struct rds_connection *conn;
 383         unsigned long flags;
 384         size_t i;
 385
 386         spin_lock_irqsave(&rds_conn_lock, flags);
 387
 388         lens->nr = 0;
 389         lens->each = item_len;
 390
 391         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 392              i++, head++) {
 393                 hlist_for_each_entry_safe(conn, pos, tmp, head, c_hash_node) {
 394
 395                         /* XXX no c_lock usage.. */
 396                         if (!visitor(conn, buffer))
 397                                 continue;
 398
 399                         /* We copy as much as we can fit in the buffer,
 400                          * but we count all items so that the caller
 401                          * can resize the buffer. */
 402                         if (len >= item_len) {
 403                                 rds_info_copy(iter, buffer, item_len);
 404                                 len -= item_len;
 405                         }
 406                         lens->nr++;
 407                 }
 408         }
 409
 410         spin_unlock_irqrestore(&rds_conn_lock, flags);
 411 }
 412 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
 413
 414 static int rds_conn_info_visitor(struct rds_connection *conn,
 415                                   void *buffer)
 416 {
 417         struct rds_info_connection *cinfo = buffer;
 418
 419         cinfo->next_tx_seq = conn->c_next_tx_seq;
 420         cinfo->next_rx_seq = conn->c_next_rx_seq;
 421         cinfo->laddr = conn->c_laddr;
 422         cinfo->faddr = conn->c_faddr;
 423         strncpy(cinfo->transport, conn->c_trans->t_name,
 424                 sizeof(cinfo->transport));
 425         cinfo->flags = 0;
 426
 427         rds_conn_info_set(cinfo->flags,
 428                           rds_conn_is_sending(conn), SENDING);
 429         /* XXX Future: return the state rather than these funky bits */
 430         rds_conn_info_set(cinfo->flags,
 431                           atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
 432                           CONNECTING);
 433         rds_conn_info_set(cinfo->flags,
 434                           atomic_read(&conn->c_state) == RDS_CONN_UP,
 435                           CONNECTED);
 436         return 1;
 437 }
 438
 439 static void rds_conn_info(struct socket *sock, unsigned int len,
 440                           struct rds_info_iterator *iter,
 441                           struct rds_info_lengths *lens)
 442 {
 443         rds_for_each_conn_info(sock, len, iter, lens,
 444                                 rds_conn_info_visitor,
 445                                 sizeof(struct rds_info_connection));
 446 }
 447
 448 int __init rds_conn_init(void)
 449 {
 450         rds_conn_slab = kmem_cache_create("rds_connection",
 451                                           sizeof(struct rds_connection),
 452                                           0, 0, NULL);
 453         if (rds_conn_slab == NULL)
 454                 return -ENOMEM;
 455
 456         rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 457         rds_info_register_func(RDS_INFO_SEND_MESSAGES,
 458                                rds_conn_message_info_send);
 459         rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
 460                                rds_conn_message_info_retrans);
 461
 462         return 0;
 463 }
 464
 465 void rds_conn_exit(void)
 466 {
 467         rds_loop_exit();
 468
 469         WARN_ON(!hlist_empty(rds_conn_hash));
 470
 471         kmem_cache_destroy(rds_conn_slab);
 472
 473         rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 474         rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
 475                                  rds_conn_message_info_send);
 476         rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
 477                                  rds_conn_message_info_retrans);
 478 }
 479
 480 /*
 481  * Force a disconnect
 482  */
 483 void rds_conn_drop(struct rds_connection *conn)
 484 {
 485         atomic_set(&conn->c_state, RDS_CONN_ERROR);
 486         queue_work(rds_wq, &conn->c_down_w);
 487 }
 488 EXPORT_SYMBOL_GPL(rds_conn_drop);
 489
 490 /*
 491  * An error occurred on the connection
 492  */
 493 void
 494 __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
 495 {
 496         va_list ap;
 497
 498         va_start(ap, fmt);
 499         vprintk(fmt, ap);
 500         va_end(ap);
 501
 502         rds_conn_drop(conn);
 503 }