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 <net/inet_hashtables.h>
  37
  38 #include "rds.h"
  39 #include "loop.h"
  40 #include "rdma.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         /* Pass NULL, don't need struct net for hash */
  55         unsigned long hash = inet_ehashfn(NULL,
  56                                           be32_to_cpu(laddr), 0,
  57                                           be32_to_cpu(faddr), 0);
  58         return &rds_conn_hash[hash & RDS_CONNECTION_HASH_MASK];
  59 }
  60
  61 #define rds_conn_info_set(var, test, suffix) do {               \
  62         if (test)                                               \
  63                 var |= RDS_INFO_CONNECTION_FLAG_##suffix;       \
  64 } while (0)
  65
  66 static inline int rds_conn_is_sending(struct rds_connection *conn)
  67 {
  68         int ret = 0;
  69
  70         if (!mutex_trylock(&conn->c_send_lock))
  71                 ret = 1;
  72         else
  73                 mutex_unlock(&conn->c_send_lock);
  74
  75         return ret;
  76 }
  77
  78 static struct rds_connection *rds_conn_lookup(struct hlist_head *head,
  79                                               __be32 laddr, __be32 faddr,
  80                                               struct rds_transport *trans)
  81 {
  82         struct rds_connection *conn, *ret = NULL;
  83         struct hlist_node *pos;
  84
  85         hlist_for_each_entry(conn, pos, head, c_hash_node) {
  86                 if (conn->c_faddr == faddr && conn->c_laddr == laddr &&
  87                                 conn->c_trans == trans) {
  88                         ret = conn;
  89                         break;
  90                 }
  91         }
  92         rdsdebug("returning conn %p for %pI4 -> %pI4\n", ret,
  93                  &laddr, &faddr);
  94         return ret;
  95 }
  96
  97 /*
  98  * This is called by transports as they're bringing down a connection.
  99  * It clears partial message state so that the transport can start sending
 100  * and receiving over this connection again in the future.  It is up to
 101  * the transport to have serialized this call with its send and recv.
 102  */
 103 void rds_conn_reset(struct rds_connection *conn)
 104 {
 105         rdsdebug("connection %pI4 to %pI4 reset\n",
 106           &conn->c_laddr, &conn->c_faddr);
 107
 108         rds_stats_inc(s_conn_reset);
 109         rds_send_reset(conn);
 110         conn->c_flags = 0;
 111
 112         /* Do not clear next_rx_seq here, else we cannot distinguish
 113          * retransmitted packets from new packets, and will hand all
 114          * of them to the application. That is not consistent with the
 115          * reliability guarantees of RDS. */
 116 }
 117
 118 /*
 119  * There is only every one 'conn' for a given pair of addresses in the
 120  * system at a time.  They contain messages to be retransmitted and so
 121  * span the lifetime of the actual underlying transport connections.
 122  *
 123  * For now they are not garbage collected once they're created.  They
 124  * are torn down as the module is removed, if ever.
 125  */
 126 static struct rds_connection *__rds_conn_create(__be32 laddr, __be32 faddr,
 127                                        struct rds_transport *trans, gfp_t gfp,
 128                                        int is_outgoing)
 129 {
 130         struct rds_connection *conn, *parent = NULL;
 131         struct hlist_head *head = rds_conn_bucket(laddr, faddr);
 132         unsigned long flags;
 133         int ret;
 134
 135         spin_lock_irqsave(&rds_conn_lock, flags);
 136         conn = rds_conn_lookup(head, laddr, faddr, trans);
 137         if (conn && conn->c_loopback && conn->c_trans != &rds_loop_transport &&
 138             !is_outgoing) {
 139                 /* This is a looped back IB connection, and we're
 140                  * called by the code handling the incoming connect.
 141                  * We need a second connection object into which we
 142                  * can stick the other QP. */
 143                 parent = conn;
 144                 conn = parent->c_passive;
 145         }
 146         spin_unlock_irqrestore(&rds_conn_lock, flags);
 147         if (conn)
 148                 goto out;
 149
 150         conn = kmem_cache_zalloc(rds_conn_slab, gfp);
 151         if (conn == NULL) {
 152                 conn = ERR_PTR(-ENOMEM);
 153                 goto out;
 154         }
 155
 156         INIT_HLIST_NODE(&conn->c_hash_node);
 157         conn->c_laddr = laddr;
 158         conn->c_faddr = faddr;
 159         spin_lock_init(&conn->c_lock);
 160         conn->c_next_tx_seq = 1;
 161
 162         mutex_init(&conn->c_send_lock);
 163         INIT_LIST_HEAD(&conn->c_send_queue);
 164         INIT_LIST_HEAD(&conn->c_retrans);
 165
 166         ret = rds_cong_get_maps(conn);
 167         if (ret) {
 168                 kmem_cache_free(rds_conn_slab, conn);
 169                 conn = ERR_PTR(ret);
 170                 goto out;
 171         }
 172
 173         /*
 174          * This is where a connection becomes loopback.  If *any* RDS sockets
 175          * can bind to the destination address then we'd rather the messages
 176          * flow through loopback rather than either transport.
 177          */
 178         if (rds_trans_get_preferred(faddr)) {
 179                 conn->c_loopback = 1;
 180                 if (is_outgoing && trans->t_prefer_loopback) {
 181                         /* "outgoing" connection - and the transport
 182                          * says it wants the connection handled by the
 183                          * loopback transport. This is what TCP does.
 184                          */
 185                         trans = &rds_loop_transport;
 186                 }
 187         }
 188
 189         conn->c_trans = trans;
 190
 191         ret = trans->conn_alloc(conn, gfp);
 192         if (ret) {
 193                 kmem_cache_free(rds_conn_slab, conn);
 194                 conn = ERR_PTR(ret);
 195                 goto out;
 196         }
 197
 198         atomic_set(&conn->c_state, RDS_CONN_DOWN);
 199         conn->c_reconnect_jiffies = 0;
 200         INIT_DELAYED_WORK(&conn->c_send_w, rds_send_worker);
 201         INIT_DELAYED_WORK(&conn->c_recv_w, rds_recv_worker);
 202         INIT_DELAYED_WORK(&conn->c_conn_w, rds_connect_worker);
 203         INIT_WORK(&conn->c_down_w, rds_shutdown_worker);
 204         mutex_init(&conn->c_cm_lock);
 205         conn->c_flags = 0;
 206
 207         rdsdebug("allocated conn %p for %pI4 -> %pI4 over %s %s\n",
 208           conn, &laddr, &faddr,
 209           trans->t_name ? trans->t_name : "[unknown]",
 210           is_outgoing ? "(outgoing)" : "");
 211
 212         /*
 213          * Since we ran without holding the conn lock, someone could
 214          * have created the same conn (either normal or passive) in the
 215          * interim. We check while holding the lock. If we won, we complete
 216          * init and return our conn. If we lost, we rollback and return the
 217          * other one.
 218          */
 219         spin_lock_irqsave(&rds_conn_lock, flags);
 220         if (parent) {
 221                 /* Creating passive conn */
 222                 if (parent->c_passive) {
 223                         trans->conn_free(conn->c_transport_data);
 224                         kmem_cache_free(rds_conn_slab, conn);
 225                         conn = parent->c_passive;
 226                 } else {
 227                         parent->c_passive = conn;
 228                         rds_cong_add_conn(conn);
 229                         rds_conn_count++;
 230                 }
 231         } else {
 232                 /* Creating normal conn */
 233                 struct rds_connection *found;
 234
 235                 found = rds_conn_lookup(head, laddr, faddr, trans);
 236                 if (found) {
 237                         trans->conn_free(conn->c_transport_data);
 238                         kmem_cache_free(rds_conn_slab, conn);
 239                         conn = found;
 240                 } else {
 241                         hlist_add_head(&conn->c_hash_node, head);
 242                         rds_cong_add_conn(conn);
 243                         rds_conn_count++;
 244                 }
 245         }
 246         spin_unlock_irqrestore(&rds_conn_lock, flags);
 247
 248 out:
 249         return conn;
 250 }
 251
 252 struct rds_connection *rds_conn_create(__be32 laddr, __be32 faddr,
 253                                        struct rds_transport *trans, gfp_t gfp)
 254 {
 255         return __rds_conn_create(laddr, faddr, trans, gfp, 0);
 256 }
 257 EXPORT_SYMBOL_GPL(rds_conn_create);
 258
 259 struct rds_connection *rds_conn_create_outgoing(__be32 laddr, __be32 faddr,
 260                                        struct rds_transport *trans, gfp_t gfp)
 261 {
 262         return __rds_conn_create(laddr, faddr, trans, gfp, 1);
 263 }
 264 EXPORT_SYMBOL_GPL(rds_conn_create_outgoing);
 265
 266 void rds_conn_destroy(struct rds_connection *conn)
 267 {
 268         struct rds_message *rm, *rtmp;
 269
 270         rdsdebug("freeing conn %p for %pI4 -> "
 271                  "%pI4\n", conn, &conn->c_laddr,
 272                  &conn->c_faddr);
 273
 274         hlist_del_init(&conn->c_hash_node);
 275
 276         /* wait for the rds thread to shut it down */
 277         atomic_set(&conn->c_state, RDS_CONN_ERROR);
 278         cancel_delayed_work(&conn->c_conn_w);
 279         queue_work(rds_wq, &conn->c_down_w);
 280         flush_workqueue(rds_wq);
 281
 282         /* tear down queued messages */
 283         list_for_each_entry_safe(rm, rtmp,
 284                                  &conn->c_send_queue,
 285                                  m_conn_item) {
 286                 list_del_init(&rm->m_conn_item);
 287                 BUG_ON(!list_empty(&rm->m_sock_item));
 288                 rds_message_put(rm);
 289         }
 290         if (conn->c_xmit_rm)
 291                 rds_message_put(conn->c_xmit_rm);
 292
 293         conn->c_trans->conn_free(conn->c_transport_data);
 294
 295         /*
 296          * The congestion maps aren't freed up here.  They're
 297          * freed by rds_cong_exit() after all the connections
 298          * have been freed.
 299          */
 300         rds_cong_remove_conn(conn);
 301
 302         BUG_ON(!list_empty(&conn->c_retrans));
 303         kmem_cache_free(rds_conn_slab, conn);
 304
 305         rds_conn_count--;
 306 }
 307 EXPORT_SYMBOL_GPL(rds_conn_destroy);
 308
 309 static void rds_conn_message_info(struct socket *sock, unsigned int len,
 310                                   struct rds_info_iterator *iter,
 311                                   struct rds_info_lengths *lens,
 312                                   int want_send)
 313 {
 314         struct hlist_head *head;
 315         struct hlist_node *pos;
 316         struct list_head *list;
 317         struct rds_connection *conn;
 318         struct rds_message *rm;
 319         unsigned long flags;
 320         unsigned int total = 0;
 321         size_t i;
 322
 323         len /= sizeof(struct rds_info_message);
 324
 325         spin_lock_irqsave(&rds_conn_lock, flags);
 326
 327         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 328              i++, head++) {
 329                 hlist_for_each_entry(conn, pos, head, c_hash_node) {
 330                         if (want_send)
 331                                 list = &conn->c_send_queue;
 332                         else
 333                                 list = &conn->c_retrans;
 334
 335                         spin_lock(&conn->c_lock);
 336
 337                         /* XXX too lazy to maintain counts.. */
 338                         list_for_each_entry(rm, list, m_conn_item) {
 339                                 total++;
 340                                 if (total <= len)
 341                                         rds_inc_info_copy(&rm->m_inc, iter,
 342                                                           conn->c_laddr,
 343                                                           conn->c_faddr, 0);
 344                         }
 345
 346                         spin_unlock(&conn->c_lock);
 347                 }
 348         }
 349
 350         spin_unlock_irqrestore(&rds_conn_lock, flags);
 351
 352         lens->nr = total;
 353         lens->each = sizeof(struct rds_info_message);
 354 }
 355
 356 static void rds_conn_message_info_send(struct socket *sock, unsigned int len,
 357                                        struct rds_info_iterator *iter,
 358                                        struct rds_info_lengths *lens)
 359 {
 360         rds_conn_message_info(sock, len, iter, lens, 1);
 361 }
 362
 363 static void rds_conn_message_info_retrans(struct socket *sock,
 364                                           unsigned int len,
 365                                           struct rds_info_iterator *iter,
 366                                           struct rds_info_lengths *lens)
 367 {
 368         rds_conn_message_info(sock, len, iter, lens, 0);
 369 }
 370
 371 void rds_for_each_conn_info(struct socket *sock, unsigned int len,
 372                           struct rds_info_iterator *iter,
 373                           struct rds_info_lengths *lens,
 374                           int (*visitor)(struct rds_connection *, void *),
 375                           size_t item_len)
 376 {
 377         uint64_t buffer[(item_len + 7) / 8];
 378         struct hlist_head *head;
 379         struct hlist_node *pos;
 380         struct hlist_node *tmp;
 381         struct rds_connection *conn;
 382         unsigned long flags;
 383         size_t i;
 384
 385         spin_lock_irqsave(&rds_conn_lock, flags);
 386
 387         lens->nr = 0;
 388         lens->each = item_len;
 389
 390         for (i = 0, head = rds_conn_hash; i < ARRAY_SIZE(rds_conn_hash);
 391              i++, head++) {
 392                 hlist_for_each_entry_safe(conn, pos, tmp, head, c_hash_node) {
 393
 394                         /* XXX no c_lock usage.. */
 395                         if (!visitor(conn, buffer))
 396                                 continue;
 397
 398                         /* We copy as much as we can fit in the buffer,
 399                          * but we count all items so that the caller
 400                          * can resize the buffer. */
 401                         if (len >= item_len) {
 402                                 rds_info_copy(iter, buffer, item_len);
 403                                 len -= item_len;
 404                         }
 405                         lens->nr++;
 406                 }
 407         }
 408
 409         spin_unlock_irqrestore(&rds_conn_lock, flags);
 410 }
 411 EXPORT_SYMBOL_GPL(rds_for_each_conn_info);
 412
 413 static int rds_conn_info_visitor(struct rds_connection *conn,
 414                                   void *buffer)
 415 {
 416         struct rds_info_connection *cinfo = buffer;
 417
 418         cinfo->next_tx_seq = conn->c_next_tx_seq;
 419         cinfo->next_rx_seq = conn->c_next_rx_seq;
 420         cinfo->laddr = conn->c_laddr;
 421         cinfo->faddr = conn->c_faddr;
 422         strncpy(cinfo->transport, conn->c_trans->t_name,
 423                 sizeof(cinfo->transport));
 424         cinfo->flags = 0;
 425
 426         rds_conn_info_set(cinfo->flags,
 427                           rds_conn_is_sending(conn), SENDING);
 428         /* XXX Future: return the state rather than these funky bits */
 429         rds_conn_info_set(cinfo->flags,
 430                           atomic_read(&conn->c_state) == RDS_CONN_CONNECTING,
 431                           CONNECTING);
 432         rds_conn_info_set(cinfo->flags,
 433                           atomic_read(&conn->c_state) == RDS_CONN_UP,
 434                           CONNECTED);
 435         return 1;
 436 }
 437
 438 static void rds_conn_info(struct socket *sock, unsigned int len,
 439                           struct rds_info_iterator *iter,
 440                           struct rds_info_lengths *lens)
 441 {
 442         rds_for_each_conn_info(sock, len, iter, lens,
 443                                 rds_conn_info_visitor,
 444                                 sizeof(struct rds_info_connection));
 445 }
 446
 447 int __init rds_conn_init(void)
 448 {
 449         rds_conn_slab = kmem_cache_create("rds_connection",
 450                                           sizeof(struct rds_connection),
 451                                           0, 0, NULL);
 452         if (rds_conn_slab == NULL)
 453                 return -ENOMEM;
 454
 455         rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 456         rds_info_register_func(RDS_INFO_SEND_MESSAGES,
 457                                rds_conn_message_info_send);
 458         rds_info_register_func(RDS_INFO_RETRANS_MESSAGES,
 459                                rds_conn_message_info_retrans);
 460
 461         return 0;
 462 }
 463
 464 void rds_conn_exit(void)
 465 {
 466         rds_loop_exit();
 467
 468         WARN_ON(!hlist_empty(rds_conn_hash));
 469
 470         kmem_cache_destroy(rds_conn_slab);
 471
 472         rds_info_deregister_func(RDS_INFO_CONNECTIONS, rds_conn_info);
 473         rds_info_deregister_func(RDS_INFO_SEND_MESSAGES,
 474                                  rds_conn_message_info_send);
 475         rds_info_deregister_func(RDS_INFO_RETRANS_MESSAGES,
 476                                  rds_conn_message_info_retrans);
 477 }
 478
 479 /*
 480  * Force a disconnect
 481  */
 482 void rds_conn_drop(struct rds_connection *conn)
 483 {
 484         atomic_set(&conn->c_state, RDS_CONN_ERROR);
 485         queue_work(rds_wq, &conn->c_down_w);
 486 }
 487 EXPORT_SYMBOL_GPL(rds_conn_drop);
 488
 489 /*
 490  * An error occurred on the connection
 491  */
 492 void
 493 __rds_conn_error(struct rds_connection *conn, const char *fmt, ...)
 494 {
 495         va_list ap;
 496
 497         va_start(ap, fmt);
 498         vprintk(fmt, ap);
 499         va_end(ap);
 500
 501         rds_conn_drop(conn);
 502 }