fs/dlm/lowcomms.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /******************************************************************************
   3 *******************************************************************************
   4 **
   5 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   6 **  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
   7 **
   8 **
   9 *******************************************************************************
  10 ******************************************************************************/
  11
  12 /*
  13  * lowcomms.c
  14  *
  15  * This is the "low-level" comms layer.
  16  *
  17  * It is responsible for sending/receiving messages
  18  * from other nodes in the cluster.
  19  *
  20  * Cluster nodes are referred to by their nodeids. nodeids are
  21  * simply 32 bit numbers to the locking module - if they need to
  22  * be expanded for the cluster infrastructure then that is its
  23  * responsibility. It is this layer's
  24  * responsibility to resolve these into IP address or
  25  * whatever it needs for inter-node communication.
  26  *
  27  * The comms level is two kernel threads that deal mainly with
  28  * the receiving of messages from other nodes and passing them
  29  * up to the mid-level comms layer (which understands the
  30  * message format) for execution by the locking core, and
  31  * a send thread which does all the setting up of connections
  32  * to remote nodes and the sending of data. Threads are not allowed
  33  * to send their own data because it may cause them to wait in times
  34  * of high load. Also, this way, the sending thread can collect together
  35  * messages bound for one node and send them in one block.
  36  *
  37  * lowcomms will choose to use either TCP or SCTP as its transport layer
  38  * depending on the configuration variable 'protocol'. This should be set
  39  * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
  40  * cluster-wide mechanism as it must be the same on all nodes of the cluster
  41  * for the DLM to function.
  42  *
  43  */
  44
  45 #include <asm/ioctls.h>
  46 #include <net/sock.h>
  47 #include <net/tcp.h>
  48 #include <linux/pagemap.h>
  49 #include <linux/file.h>
  50 #include <linux/mutex.h>
  51 #include <linux/sctp.h>
  52 #include <linux/slab.h>
  53 #include <net/sctp/sctp.h>
  54 #include <net/ipv6.h>
  55
  56 #include "dlm_internal.h"
  57 #include "lowcomms.h"
  58 #include "midcomms.h"
  59 #include "config.h"
  60
  61 #define NEEDED_RMEM (4*1024*1024)
  62 #define CONN_HASH_SIZE 32
  63
  64 /* Number of messages to send before rescheduling */
  65 #define MAX_SEND_MSG_COUNT 25
  66 #define DLM_SHUTDOWN_WAIT_TIMEOUT msecs_to_jiffies(10000)
  67
  68 struct cbuf {
  69         unsigned int base;
  70         unsigned int len;
  71         unsigned int mask;
  72 };
  73
  74 static void cbuf_add(struct cbuf *cb, int n)
  75 {
  76         cb->len += n;
  77 }
  78
  79 static int cbuf_data(struct cbuf *cb)
  80 {
  81         return ((cb->base + cb->len) & cb->mask);
  82 }
  83
  84 static void cbuf_init(struct cbuf *cb, int size)
  85 {
  86         cb->base = cb->len = 0;
  87         cb->mask = size-1;
  88 }
  89
  90 static void cbuf_eat(struct cbuf *cb, int n)
  91 {
  92         cb->len  -= n;
  93         cb->base += n;
  94         cb->base &= cb->mask;
  95 }
  96
  97 static bool cbuf_empty(struct cbuf *cb)
  98 {
  99         return cb->len == 0;
 100 }
 101
 102 struct connection {
 103         struct socket *sock;    /* NULL if not connected */
 104         uint32_t nodeid;        /* So we know who we are in the list */
 105         struct mutex sock_mutex;
 106         unsigned long flags;
 107 #define CF_READ_PENDING 1
 108 #define CF_WRITE_PENDING 2
 109 #define CF_INIT_PENDING 4
 110 #define CF_IS_OTHERCON 5
 111 #define CF_CLOSE 6
 112 #define CF_APP_LIMITED 7
 113 #define CF_CLOSING 8
 114 #define CF_SHUTDOWN 9
 115         struct list_head writequeue;  /* List of outgoing writequeue_entries */
 116         spinlock_t writequeue_lock;
 117         int (*rx_action) (struct connection *); /* What to do when active */
 118         void (*connect_action) (struct connection *);   /* What to do to connect */
 119         void (*shutdown_action)(struct connection *con); /* What to do to shutdown */
 120         struct page *rx_page;
 121         struct cbuf cb;
 122         int retries;
 123 #define MAX_CONNECT_RETRIES 3
 124         struct hlist_node list;
 125         struct connection *othercon;
 126         struct work_struct rwork; /* Receive workqueue */
 127         struct work_struct swork; /* Send workqueue */
 128         wait_queue_head_t shutdown_wait; /* wait for graceful shutdown */
 129         struct rcu_head rcu;
 130 };
 131 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
 132
 133 /* An entry waiting to be sent */
 134 struct writequeue_entry {
 135         struct list_head list;
 136         struct page *page;
 137         int offset;
 138         int len;
 139         int end;
 140         int users;
 141         struct connection *con;
 142 };
 143
 144 struct dlm_node_addr {
 145         struct list_head list;
 146         int nodeid;
 147         int addr_count;
 148         int curr_addr_index;
 149         struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
 150 };
 151
 152 static struct listen_sock_callbacks {
 153         void (*sk_error_report)(struct sock *);
 154         void (*sk_data_ready)(struct sock *);
 155         void (*sk_state_change)(struct sock *);
 156         void (*sk_write_space)(struct sock *);
 157 } listen_sock;
 158
 159 static LIST_HEAD(dlm_node_addrs);
 160 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
 161
 162 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
 163 static int dlm_local_count;
 164 static int dlm_allow_conn;
 165
 166 /* Work queues */
 167 static struct workqueue_struct *recv_workqueue;
 168 static struct workqueue_struct *send_workqueue;
 169
 170 static struct hlist_head connection_hash[CONN_HASH_SIZE];
 171 static DEFINE_SPINLOCK(connections_lock);
 172 DEFINE_STATIC_SRCU(connections_srcu);
 173
 174 static void process_recv_sockets(struct work_struct *work);
 175 static void process_send_sockets(struct work_struct *work);
 176
 177
 178 /* This is deliberately very simple because most clusters have simple
 179    sequential nodeids, so we should be able to go straight to a connection
 180    struct in the array */
 181 static inline int nodeid_hash(int nodeid)
 182 {
 183         return nodeid & (CONN_HASH_SIZE-1);
 184 }
 185
 186 static struct connection *__find_con(int nodeid)
 187 {
 188         int r, idx;
 189         struct connection *con;
 190
 191         r = nodeid_hash(nodeid);
 192
 193         idx = srcu_read_lock(&connections_srcu);
 194         hlist_for_each_entry_rcu(con, &connection_hash[r], list) {
 195                 if (con->nodeid == nodeid) {
 196                         srcu_read_unlock(&connections_srcu, idx);
 197                         return con;
 198                 }
 199         }
 200         srcu_read_unlock(&connections_srcu, idx);
 201
 202         return NULL;
 203 }
 204
 205 /*
 206  * If 'allocation' is zero then we don't attempt to create a new
 207  * connection structure for this node.
 208  */
 209 static struct connection *nodeid2con(int nodeid, gfp_t alloc)
 210 {
 211         struct connection *con = NULL;
 212         int r;
 213
 214         con = __find_con(nodeid);
 215         if (con || !alloc)
 216                 return con;
 217
 218         con = kzalloc(sizeof(*con), alloc);
 219         if (!con)
 220                 return NULL;
 221
 222         con->nodeid = nodeid;
 223         mutex_init(&con->sock_mutex);
 224         INIT_LIST_HEAD(&con->writequeue);
 225         spin_lock_init(&con->writequeue_lock);
 226         INIT_WORK(&con->swork, process_send_sockets);
 227         INIT_WORK(&con->rwork, process_recv_sockets);
 228         init_waitqueue_head(&con->shutdown_wait);
 229
 230         /* Setup action pointers for child sockets */
 231         if (con->nodeid) {
 232                 struct connection *zerocon = __find_con(0);
 233
 234                 con->connect_action = zerocon->connect_action;
 235                 if (!con->rx_action)
 236                         con->rx_action = zerocon->rx_action;
 237         }
 238
 239         r = nodeid_hash(nodeid);
 240
 241         spin_lock(&connections_lock);
 242         hlist_add_head_rcu(&con->list, &connection_hash[r]);
 243         spin_unlock(&connections_lock);
 244
 245         return con;
 246 }
 247
 248 /* Loop round all connections */
 249 static void foreach_conn(void (*conn_func)(struct connection *c))
 250 {
 251         int i, idx;
 252         struct connection *con;
 253
 254         idx = srcu_read_lock(&connections_srcu);
 255         for (i = 0; i < CONN_HASH_SIZE; i++) {
 256                 hlist_for_each_entry_rcu(con, &connection_hash[i], list)
 257                         conn_func(con);
 258         }
 259         srcu_read_unlock(&connections_srcu, idx);
 260 }
 261
 262 static struct dlm_node_addr *find_node_addr(int nodeid)
 263 {
 264         struct dlm_node_addr *na;
 265
 266         list_for_each_entry(na, &dlm_node_addrs, list) {
 267                 if (na->nodeid == nodeid)
 268                         return na;
 269         }
 270         return NULL;
 271 }
 272
 273 static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
 274 {
 275         switch (x->ss_family) {
 276         case AF_INET: {
 277                 struct sockaddr_in *sinx = (struct sockaddr_in *)x;
 278                 struct sockaddr_in *siny = (struct sockaddr_in *)y;
 279                 if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
 280                         return 0;
 281                 if (sinx->sin_port != siny->sin_port)
 282                         return 0;
 283                 break;
 284         }
 285         case AF_INET6: {
 286                 struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
 287                 struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
 288                 if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
 289                         return 0;
 290                 if (sinx->sin6_port != siny->sin6_port)
 291                         return 0;
 292                 break;
 293         }
 294         default:
 295                 return 0;
 296         }
 297         return 1;
 298 }
 299
 300 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
 301                           struct sockaddr *sa_out, bool try_new_addr)
 302 {
 303         struct sockaddr_storage sas;
 304         struct dlm_node_addr *na;
 305
 306         if (!dlm_local_count)
 307                 return -1;
 308
 309         spin_lock(&dlm_node_addrs_spin);
 310         na = find_node_addr(nodeid);
 311         if (na && na->addr_count) {
 312                 memcpy(&sas, na->addr[na->curr_addr_index],
 313                        sizeof(struct sockaddr_storage));
 314
 315                 if (try_new_addr) {
 316                         na->curr_addr_index++;
 317                         if (na->curr_addr_index == na->addr_count)
 318                                 na->curr_addr_index = 0;
 319                 }
 320         }
 321         spin_unlock(&dlm_node_addrs_spin);
 322
 323         if (!na)
 324                 return -EEXIST;
 325
 326         if (!na->addr_count)
 327                 return -ENOENT;
 328
 329         if (sas_out)
 330                 memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
 331
 332         if (!sa_out)
 333                 return 0;
 334
 335         if (dlm_local_addr[0]->ss_family == AF_INET) {
 336                 struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
 337                 struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
 338                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
 339         } else {
 340                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &sas;
 341                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
 342                 ret6->sin6_addr = in6->sin6_addr;
 343         }
 344
 345         return 0;
 346 }
 347
 348 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
 349 {
 350         struct dlm_node_addr *na;
 351         int rv = -EEXIST;
 352         int addr_i;
 353
 354         spin_lock(&dlm_node_addrs_spin);
 355         list_for_each_entry(na, &dlm_node_addrs, list) {
 356                 if (!na->addr_count)
 357                         continue;
 358
 359                 for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
 360                         if (addr_compare(na->addr[addr_i], addr)) {
 361                                 *nodeid = na->nodeid;
 362                                 rv = 0;
 363                                 goto unlock;
 364                         }
 365                 }
 366         }
 367 unlock:
 368         spin_unlock(&dlm_node_addrs_spin);
 369         return rv;
 370 }
 371
 372 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
 373 {
 374         struct sockaddr_storage *new_addr;
 375         struct dlm_node_addr *new_node, *na;
 376
 377         new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
 378         if (!new_node)
 379                 return -ENOMEM;
 380
 381         new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
 382         if (!new_addr) {
 383                 kfree(new_node);
 384                 return -ENOMEM;
 385         }
 386
 387         memcpy(new_addr, addr, len);
 388
 389         spin_lock(&dlm_node_addrs_spin);
 390         na = find_node_addr(nodeid);
 391         if (!na) {
 392                 new_node->nodeid = nodeid;
 393                 new_node->addr[0] = new_addr;
 394                 new_node->addr_count = 1;
 395                 list_add(&new_node->list, &dlm_node_addrs);
 396                 spin_unlock(&dlm_node_addrs_spin);
 397                 return 0;
 398         }
 399
 400         if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
 401                 spin_unlock(&dlm_node_addrs_spin);
 402                 kfree(new_addr);
 403                 kfree(new_node);
 404                 return -ENOSPC;
 405         }
 406
 407         na->addr[na->addr_count++] = new_addr;
 408         spin_unlock(&dlm_node_addrs_spin);
 409         kfree(new_node);
 410         return 0;
 411 }
 412
 413 /* Data available on socket or listen socket received a connect */
 414 static void lowcomms_data_ready(struct sock *sk)
 415 {
 416         struct connection *con;
 417
 418         read_lock_bh(&sk->sk_callback_lock);
 419         con = sock2con(sk);
 420         if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
 421                 queue_work(recv_workqueue, &con->rwork);
 422         read_unlock_bh(&sk->sk_callback_lock);
 423 }
 424
 425 static void lowcomms_write_space(struct sock *sk)
 426 {
 427         struct connection *con;
 428
 429         read_lock_bh(&sk->sk_callback_lock);
 430         con = sock2con(sk);
 431         if (!con)
 432                 goto out;
 433
 434         clear_bit(SOCK_NOSPACE, &con->sock->flags);
 435
 436         if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
 437                 con->sock->sk->sk_write_pending--;
 438                 clear_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags);
 439         }
 440
 441         queue_work(send_workqueue, &con->swork);
 442 out:
 443         read_unlock_bh(&sk->sk_callback_lock);
 444 }
 445
 446 static inline void lowcomms_connect_sock(struct connection *con)
 447 {
 448         if (test_bit(CF_CLOSE, &con->flags))
 449                 return;
 450         queue_work(send_workqueue, &con->swork);
 451         cond_resched();
 452 }
 453
 454 static void lowcomms_state_change(struct sock *sk)
 455 {
 456         /* SCTP layer is not calling sk_data_ready when the connection
 457          * is done, so we catch the signal through here. Also, it
 458          * doesn't switch socket state when entering shutdown, so we
 459          * skip the write in that case.
 460          */
 461         if (sk->sk_shutdown) {
 462                 if (sk->sk_shutdown == RCV_SHUTDOWN)
 463                         lowcomms_data_ready(sk);
 464         } else if (sk->sk_state == TCP_ESTABLISHED) {
 465                 lowcomms_write_space(sk);
 466         }
 467 }
 468
 469 int dlm_lowcomms_connect_node(int nodeid)
 470 {
 471         struct connection *con;
 472
 473         if (nodeid == dlm_our_nodeid())
 474                 return 0;
 475
 476         con = nodeid2con(nodeid, GFP_NOFS);
 477         if (!con)
 478                 return -ENOMEM;
 479         lowcomms_connect_sock(con);
 480         return 0;
 481 }
 482
 483 static void lowcomms_error_report(struct sock *sk)
 484 {
 485         struct connection *con;
 486         struct sockaddr_storage saddr;
 487         void (*orig_report)(struct sock *) = NULL;
 488
 489         read_lock_bh(&sk->sk_callback_lock);
 490         con = sock2con(sk);
 491         if (con == NULL)
 492                 goto out;
 493
 494         orig_report = listen_sock.sk_error_report;
 495         if (con->sock == NULL ||
 496             kernel_getpeername(con->sock, (struct sockaddr *)&saddr) < 0) {
 497                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 498                                    "sending to node %d, port %d, "
 499                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
 500                                    con->nodeid, dlm_config.ci_tcp_port,
 501                                    sk->sk_err, sk->sk_err_soft);
 502         } else if (saddr.ss_family == AF_INET) {
 503                 struct sockaddr_in *sin4 = (struct sockaddr_in *)&saddr;
 504
 505                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 506                                    "sending to node %d at %pI4, port %d, "
 507                                    "sk_err=%d/%d\n", dlm_our_nodeid(),
 508                                    con->nodeid, &sin4->sin_addr.s_addr,
 509                                    dlm_config.ci_tcp_port, sk->sk_err,
 510                                    sk->sk_err_soft);
 511         } else {
 512                 struct sockaddr_in6 *sin6 = (struct sockaddr_in6 *)&saddr;
 513
 514                 printk_ratelimited(KERN_ERR "dlm: node %d: socket error "
 515                                    "sending to node %d at %u.%u.%u.%u, "
 516                                    "port %d, sk_err=%d/%d\n", dlm_our_nodeid(),
 517                                    con->nodeid, sin6->sin6_addr.s6_addr32[0],
 518                                    sin6->sin6_addr.s6_addr32[1],
 519                                    sin6->sin6_addr.s6_addr32[2],
 520                                    sin6->sin6_addr.s6_addr32[3],
 521                                    dlm_config.ci_tcp_port, sk->sk_err,
 522                                    sk->sk_err_soft);
 523         }
 524 out:
 525         read_unlock_bh(&sk->sk_callback_lock);
 526         if (orig_report)
 527                 orig_report(sk);
 528 }
 529
 530 /* Note: sk_callback_lock must be locked before calling this function. */
 531 static void save_listen_callbacks(struct socket *sock)
 532 {
 533         struct sock *sk = sock->sk;
 534
 535         listen_sock.sk_data_ready = sk->sk_data_ready;
 536         listen_sock.sk_state_change = sk->sk_state_change;
 537         listen_sock.sk_write_space = sk->sk_write_space;
 538         listen_sock.sk_error_report = sk->sk_error_report;
 539 }
 540
 541 static void restore_callbacks(struct socket *sock)
 542 {
 543         struct sock *sk = sock->sk;
 544
 545         write_lock_bh(&sk->sk_callback_lock);
 546         sk->sk_user_data = NULL;
 547         sk->sk_data_ready = listen_sock.sk_data_ready;
 548         sk->sk_state_change = listen_sock.sk_state_change;
 549         sk->sk_write_space = listen_sock.sk_write_space;
 550         sk->sk_error_report = listen_sock.sk_error_report;
 551         write_unlock_bh(&sk->sk_callback_lock);
 552 }
 553
 554 /* Make a socket active */
 555 static void add_sock(struct socket *sock, struct connection *con)
 556 {
 557         struct sock *sk = sock->sk;
 558
 559         write_lock_bh(&sk->sk_callback_lock);
 560         con->sock = sock;
 561
 562         sk->sk_user_data = con;
 563         /* Install a data_ready callback */
 564         sk->sk_data_ready = lowcomms_data_ready;
 565         sk->sk_write_space = lowcomms_write_space;
 566         sk->sk_state_change = lowcomms_state_change;
 567         sk->sk_allocation = GFP_NOFS;
 568         sk->sk_error_report = lowcomms_error_report;
 569         write_unlock_bh(&sk->sk_callback_lock);
 570 }
 571
 572 /* Add the port number to an IPv6 or 4 sockaddr and return the address
 573    length */
 574 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 575                           int *addr_len)
 576 {
 577         saddr->ss_family =  dlm_local_addr[0]->ss_family;
 578         if (saddr->ss_family == AF_INET) {
 579                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
 580                 in4_addr->sin_port = cpu_to_be16(port);
 581                 *addr_len = sizeof(struct sockaddr_in);
 582                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
 583         } else {
 584                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
 585                 in6_addr->sin6_port = cpu_to_be16(port);
 586                 *addr_len = sizeof(struct sockaddr_in6);
 587         }
 588         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
 589 }
 590
 591 /* Close a remote connection and tidy up */
 592 static void close_connection(struct connection *con, bool and_other,
 593                              bool tx, bool rx)
 594 {
 595         bool closing = test_and_set_bit(CF_CLOSING, &con->flags);
 596
 597         if (tx && !closing && cancel_work_sync(&con->swork)) {
 598                 log_print("canceled swork for node %d", con->nodeid);
 599                 clear_bit(CF_WRITE_PENDING, &con->flags);
 600         }
 601         if (rx && !closing && cancel_work_sync(&con->rwork)) {
 602                 log_print("canceled rwork for node %d", con->nodeid);
 603                 clear_bit(CF_READ_PENDING, &con->flags);
 604         }
 605
 606         mutex_lock(&con->sock_mutex);
 607         if (con->sock) {
 608                 restore_callbacks(con->sock);
 609                 sock_release(con->sock);
 610                 con->sock = NULL;
 611         }
 612         if (con->othercon && and_other) {
 613                 /* Will only re-enter once. */
 614                 close_connection(con->othercon, false, true, true);
 615         }
 616         if (con->rx_page) {
 617                 __free_page(con->rx_page);
 618                 con->rx_page = NULL;
 619         }
 620
 621         con->retries = 0;
 622         mutex_unlock(&con->sock_mutex);
 623         clear_bit(CF_CLOSING, &con->flags);
 624 }
 625
 626 static void shutdown_connection(struct connection *con)
 627 {
 628         int ret;
 629
 630         if (cancel_work_sync(&con->swork)) {
 631                 log_print("canceled swork for node %d", con->nodeid);
 632                 clear_bit(CF_WRITE_PENDING, &con->flags);
 633         }
 634
 635         mutex_lock(&con->sock_mutex);
 636         /* nothing to shutdown */
 637         if (!con->sock) {
 638                 mutex_unlock(&con->sock_mutex);
 639                 return;
 640         }
 641
 642         set_bit(CF_SHUTDOWN, &con->flags);
 643         ret = kernel_sock_shutdown(con->sock, SHUT_WR);
 644         mutex_unlock(&con->sock_mutex);
 645         if (ret) {
 646                 log_print("Connection %p failed to shutdown: %d will force close",
 647                           con, ret);
 648                 goto force_close;
 649         } else {
 650                 ret = wait_event_timeout(con->shutdown_wait,
 651                                          !test_bit(CF_SHUTDOWN, &con->flags),
 652                                          DLM_SHUTDOWN_WAIT_TIMEOUT);
 653                 if (ret == 0) {
 654                         log_print("Connection %p shutdown timed out, will force close",
 655                                   con);
 656                         goto force_close;
 657                 }
 658         }
 659
 660         return;
 661
 662 force_close:
 663         clear_bit(CF_SHUTDOWN, &con->flags);
 664         close_connection(con, false, true, true);
 665 }
 666
 667 static void dlm_tcp_shutdown(struct connection *con)
 668 {
 669         if (con->othercon)
 670                 shutdown_connection(con->othercon);
 671         shutdown_connection(con);
 672 }
 673
 674 /* Data received from remote end */
 675 static int receive_from_sock(struct connection *con)
 676 {
 677         int ret = 0;
 678         struct msghdr msg = {};
 679         struct kvec iov[2];
 680         unsigned len;
 681         int r;
 682         int call_again_soon = 0;
 683         int nvec;
 684
 685         mutex_lock(&con->sock_mutex);
 686
 687         if (con->sock == NULL) {
 688                 ret = -EAGAIN;
 689                 goto out_close;
 690         }
 691         if (con->nodeid == 0) {
 692                 ret = -EINVAL;
 693                 goto out_close;
 694         }
 695
 696         if (con->rx_page == NULL) {
 697                 /*
 698                  * This doesn't need to be atomic, but I think it should
 699                  * improve performance if it is.
 700                  */
 701                 con->rx_page = alloc_page(GFP_ATOMIC);
 702                 if (con->rx_page == NULL)
 703                         goto out_resched;
 704                 cbuf_init(&con->cb, PAGE_SIZE);
 705         }
 706
 707         /*
 708          * iov[0] is the bit of the circular buffer between the current end
 709          * point (cb.base + cb.len) and the end of the buffer.
 710          */
 711         iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
 712         iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
 713         iov[1].iov_len = 0;
 714         nvec = 1;
 715
 716         /*
 717          * iov[1] is the bit of the circular buffer between the start of the
 718          * buffer and the start of the currently used section (cb.base)
 719          */
 720         if (cbuf_data(&con->cb) >= con->cb.base) {
 721                 iov[0].iov_len = PAGE_SIZE - cbuf_data(&con->cb);
 722                 iov[1].iov_len = con->cb.base;
 723                 iov[1].iov_base = page_address(con->rx_page);
 724                 nvec = 2;
 725         }
 726         len = iov[0].iov_len + iov[1].iov_len;
 727         iov_iter_kvec(&msg.msg_iter, READ, iov, nvec, len);
 728
 729         r = ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT | MSG_NOSIGNAL);
 730         if (ret <= 0)
 731                 goto out_close;
 732         else if (ret == len)
 733                 call_again_soon = 1;
 734
 735         cbuf_add(&con->cb, ret);
 736         ret = dlm_process_incoming_buffer(con->nodeid,
 737                                           page_address(con->rx_page),
 738                                           con->cb.base, con->cb.len,
 739                                           PAGE_SIZE);
 740         if (ret < 0) {
 741                 log_print("lowcomms err %d: addr=%p, base=%u, len=%u, read=%d",
 742                           ret, page_address(con->rx_page), con->cb.base,
 743                           con->cb.len, r);
 744                 cbuf_eat(&con->cb, r);
 745         } else {
 746                 cbuf_eat(&con->cb, ret);
 747         }
 748
 749         if (cbuf_empty(&con->cb) && !call_again_soon) {
 750                 __free_page(con->rx_page);
 751                 con->rx_page = NULL;
 752         }
 753
 754         if (call_again_soon)
 755                 goto out_resched;
 756         mutex_unlock(&con->sock_mutex);
 757         return 0;
 758
 759 out_resched:
 760         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
 761                 queue_work(recv_workqueue, &con->rwork);
 762         mutex_unlock(&con->sock_mutex);
 763         return -EAGAIN;
 764
 765 out_close:
 766         mutex_unlock(&con->sock_mutex);
 767         if (ret != -EAGAIN) {
 768                 /* Reconnect when there is something to send */
 769                 close_connection(con, false, true, false);
 770                 if (ret == 0) {
 771                         log_print("connection %p got EOF from %d",
 772                                   con, con->nodeid);
 773                         /* handling for tcp shutdown */
 774                         clear_bit(CF_SHUTDOWN, &con->flags);
 775                         wake_up(&con->shutdown_wait);
 776                         /* signal to breaking receive worker */
 777                         ret = -1;
 778                 }
 779         }
 780         return ret;
 781 }
 782
 783 /* Listening socket is busy, accept a connection */
 784 static int accept_from_sock(struct connection *con)
 785 {
 786         int result;
 787         struct sockaddr_storage peeraddr;
 788         struct socket *newsock;
 789         int len;
 790         int nodeid;
 791         struct connection *newcon;
 792         struct connection *addcon;
 793
 794         if (!dlm_allow_conn) {
 795                 return -1;
 796         }
 797
 798         mutex_lock_nested(&con->sock_mutex, 0);
 799
 800         if (!con->sock) {
 801                 mutex_unlock(&con->sock_mutex);
 802                 return -ENOTCONN;
 803         }
 804
 805         result = kernel_accept(con->sock, &newsock, O_NONBLOCK);
 806         if (result < 0)
 807                 goto accept_err;
 808
 809         /* Get the connected socket's peer */
 810         memset(&peeraddr, 0, sizeof(peeraddr));
 811         len = newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr, 2);
 812         if (len < 0) {
 813                 result = -ECONNABORTED;
 814                 goto accept_err;
 815         }
 816
 817         /* Get the new node's NODEID */
 818         make_sockaddr(&peeraddr, 0, &len);
 819         if (addr_to_nodeid(&peeraddr, &nodeid)) {
 820                 unsigned char *b=(unsigned char *)&peeraddr;
 821                 log_print("connect from non cluster node");
 822                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
 823                                      b, sizeof(struct sockaddr_storage));
 824                 sock_release(newsock);
 825                 mutex_unlock(&con->sock_mutex);
 826                 return -1;
 827         }
 828
 829         log_print("got connection from %d", nodeid);
 830
 831         /*  Check to see if we already have a connection to this node. This
 832          *  could happen if the two nodes initiate a connection at roughly
 833          *  the same time and the connections cross on the wire.
 834          *  In this case we store the incoming one in "othercon"
 835          */
 836         newcon = nodeid2con(nodeid, GFP_NOFS);
 837         if (!newcon) {
 838                 result = -ENOMEM;
 839                 goto accept_err;
 840         }
 841         mutex_lock_nested(&newcon->sock_mutex, 1);
 842         if (newcon->sock) {
 843                 struct connection *othercon = newcon->othercon;
 844
 845                 if (!othercon) {
 846                         othercon = kzalloc(sizeof(*othercon), GFP_NOFS);
 847                         if (!othercon) {
 848                                 log_print("failed to allocate incoming socket");
 849                                 mutex_unlock(&newcon->sock_mutex);
 850                                 result = -ENOMEM;
 851                                 goto accept_err;
 852                         }
 853                         othercon->nodeid = nodeid;
 854                         othercon->rx_action = receive_from_sock;
 855                         mutex_init(&othercon->sock_mutex);
 856                         INIT_LIST_HEAD(&othercon->writequeue);
 857                         spin_lock_init(&othercon->writequeue_lock);
 858                         INIT_WORK(&othercon->swork, process_send_sockets);
 859                         INIT_WORK(&othercon->rwork, process_recv_sockets);
 860                         init_waitqueue_head(&othercon->shutdown_wait);
 861                         set_bit(CF_IS_OTHERCON, &othercon->flags);
 862                 } else {
 863                         /* close other sock con if we have something new */
 864                         close_connection(othercon, false, true, false);
 865                 }
 866
 867                 mutex_lock_nested(&othercon->sock_mutex, 2);
 868                 newcon->othercon = othercon;
 869                 add_sock(newsock, othercon);
 870                 addcon = othercon;
 871                 mutex_unlock(&othercon->sock_mutex);
 872         }
 873         else {
 874                 newcon->rx_action = receive_from_sock;
 875                 /* accept copies the sk after we've saved the callbacks, so we
 876                    don't want to save them a second time or comm errors will
 877                    result in calling sk_error_report recursively. */
 878                 add_sock(newsock, newcon);
 879                 addcon = newcon;
 880         }
 881
 882         mutex_unlock(&newcon->sock_mutex);
 883
 884         /*
 885          * Add it to the active queue in case we got data
 886          * between processing the accept adding the socket
 887          * to the read_sockets list
 888          */
 889         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
 890                 queue_work(recv_workqueue, &addcon->rwork);
 891         mutex_unlock(&con->sock_mutex);
 892
 893         return 0;
 894
 895 accept_err:
 896         mutex_unlock(&con->sock_mutex);
 897         if (newsock)
 898                 sock_release(newsock);
 899
 900         if (result != -EAGAIN)
 901                 log_print("error accepting connection from node: %d", result);
 902         return result;
 903 }
 904
 905 static void free_entry(struct writequeue_entry *e)
 906 {
 907         __free_page(e->page);
 908         kfree(e);
 909 }
 910
 911 /*
 912  * writequeue_entry_complete - try to delete and free write queue entry
 913  * @e: write queue entry to try to delete
 914  * @completed: bytes completed
 915  *
 916  * writequeue_lock must be held.
 917  */
 918 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
 919 {
 920         e->offset += completed;
 921         e->len -= completed;
 922
 923         if (e->len == 0 && e->users == 0) {
 924                 list_del(&e->list);
 925                 free_entry(e);
 926         }
 927 }
 928
 929 /*
 930  * sctp_bind_addrs - bind a SCTP socket to all our addresses
 931  */
 932 static int sctp_bind_addrs(struct connection *con, uint16_t port)
 933 {
 934         struct sockaddr_storage localaddr;
 935         struct sockaddr *addr = (struct sockaddr *)&localaddr;
 936         int i, addr_len, result = 0;
 937
 938         for (i = 0; i < dlm_local_count; i++) {
 939                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
 940                 make_sockaddr(&localaddr, port, &addr_len);
 941
 942                 if (!i)
 943                         result = kernel_bind(con->sock, addr, addr_len);
 944                 else
 945                         result = sock_bind_add(con->sock->sk, addr, addr_len);
 946
 947                 if (result < 0) {
 948                         log_print("Can't bind to %d addr number %d, %d.\n",
 949                                   port, i + 1, result);
 950                         break;
 951                 }
 952         }
 953         return result;
 954 }
 955
 956 /* Initiate an SCTP association.
 957    This is a special case of send_to_sock() in that we don't yet have a
 958    peeled-off socket for this association, so we use the listening socket
 959    and add the primary IP address of the remote node.
 960  */
 961 static void sctp_connect_to_sock(struct connection *con)
 962 {
 963         struct sockaddr_storage daddr;
 964         int result;
 965         int addr_len;
 966         struct socket *sock;
 967         unsigned int mark;
 968
 969         if (con->nodeid == 0) {
 970                 log_print("attempt to connect sock 0 foiled");
 971                 return;
 972         }
 973
 974         mutex_lock(&con->sock_mutex);
 975
 976         /* Some odd races can cause double-connects, ignore them */
 977         if (con->retries++ > MAX_CONNECT_RETRIES)
 978                 goto out;
 979
 980         if (con->sock) {
 981                 log_print("node %d already connected.", con->nodeid);
 982                 goto out;
 983         }
 984
 985         memset(&daddr, 0, sizeof(daddr));
 986         result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
 987         if (result < 0) {
 988                 log_print("no address for nodeid %d", con->nodeid);
 989                 goto out;
 990         }
 991
 992         /* Create a socket to communicate with */
 993         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
 994                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
 995         if (result < 0)
 996                 goto socket_err;
 997
 998         /* set skb mark */
 999         result = dlm_comm_mark(con->nodeid, &mark);
1000         if (result < 0)
1001                 goto bind_err;
1002
1003         sock_set_mark(sock->sk, mark);
1004
1005         con->rx_action = receive_from_sock;
1006         con->connect_action = sctp_connect_to_sock;
1007         add_sock(sock, con);
1008
1009         /* Bind to all addresses. */
1010         if (sctp_bind_addrs(con, 0))
1011                 goto bind_err;
1012
1013         make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
1014
1015         log_print("connecting to %d", con->nodeid);
1016
1017         /* Turn off Nagle's algorithm */
1018         sctp_sock_set_nodelay(sock->sk);
1019
1020         /*
1021          * Make sock->ops->connect() function return in specified time,
1022          * since O_NONBLOCK argument in connect() function does not work here,
1023          * then, we should restore the default value of this attribute.
1024          */
1025         sock_set_sndtimeo(sock->sk, 5);
1026         result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
1027                                    0);
1028         sock_set_sndtimeo(sock->sk, 0);
1029
1030         if (result == -EINPROGRESS)
1031                 result = 0;
1032         if (result == 0)
1033                 goto out;
1034
1035 bind_err:
1036         con->sock = NULL;
1037         sock_release(sock);
1038
1039 socket_err:
1040         /*
1041          * Some errors are fatal and this list might need adjusting. For other
1042          * errors we try again until the max number of retries is reached.
1043          */
1044         if (result != -EHOSTUNREACH &&
1045             result != -ENETUNREACH &&
1046             result != -ENETDOWN &&
1047             result != -EINVAL &&
1048             result != -EPROTONOSUPPORT) {
1049                 log_print("connect %d try %d error %d", con->nodeid,
1050                           con->retries, result);
1051                 mutex_unlock(&con->sock_mutex);
1052                 msleep(1000);
1053                 lowcomms_connect_sock(con);
1054                 return;
1055         }
1056
1057 out:
1058         mutex_unlock(&con->sock_mutex);
1059 }
1060
1061 /* Connect a new socket to its peer */
1062 static void tcp_connect_to_sock(struct connection *con)
1063 {
1064         struct sockaddr_storage saddr, src_addr;
1065         int addr_len;
1066         struct socket *sock = NULL;
1067         unsigned int mark;
1068         int result;
1069
1070         if (con->nodeid == 0) {
1071                 log_print("attempt to connect sock 0 foiled");
1072                 return;
1073         }
1074
1075         mutex_lock(&con->sock_mutex);
1076         if (con->retries++ > MAX_CONNECT_RETRIES)
1077                 goto out;
1078
1079         /* Some odd races can cause double-connects, ignore them */
1080         if (con->sock)
1081                 goto out;
1082
1083         /* Create a socket to communicate with */
1084         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1085                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1086         if (result < 0)
1087                 goto out_err;
1088
1089         /* set skb mark */
1090         result = dlm_comm_mark(con->nodeid, &mark);
1091         if (result < 0)
1092                 goto out_err;
1093
1094         sock_set_mark(sock->sk, mark);
1095
1096         memset(&saddr, 0, sizeof(saddr));
1097         result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
1098         if (result < 0) {
1099                 log_print("no address for nodeid %d", con->nodeid);
1100                 goto out_err;
1101         }
1102
1103         con->rx_action = receive_from_sock;
1104         con->connect_action = tcp_connect_to_sock;
1105         con->shutdown_action = dlm_tcp_shutdown;
1106         add_sock(sock, con);
1107
1108         /* Bind to our cluster-known address connecting to avoid
1109            routing problems */
1110         memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
1111         make_sockaddr(&src_addr, 0, &addr_len);
1112         result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
1113                                  addr_len);
1114         if (result < 0) {
1115                 log_print("could not bind for connect: %d", result);
1116                 /* This *may* not indicate a critical error */
1117         }
1118
1119         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
1120
1121         log_print("connecting to %d", con->nodeid);
1122
1123         /* Turn off Nagle's algorithm */
1124         tcp_sock_set_nodelay(sock->sk);
1125
1126         result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
1127                                    O_NONBLOCK);
1128         if (result == -EINPROGRESS)
1129                 result = 0;
1130         if (result == 0)
1131                 goto out;
1132
1133 out_err:
1134         if (con->sock) {
1135                 sock_release(con->sock);
1136                 con->sock = NULL;
1137         } else if (sock) {
1138                 sock_release(sock);
1139         }
1140         /*
1141          * Some errors are fatal and this list might need adjusting. For other
1142          * errors we try again until the max number of retries is reached.
1143          */
1144         if (result != -EHOSTUNREACH &&
1145             result != -ENETUNREACH &&
1146             result != -ENETDOWN &&
1147             result != -EINVAL &&
1148             result != -EPROTONOSUPPORT) {
1149                 log_print("connect %d try %d error %d", con->nodeid,
1150                           con->retries, result);
1151                 mutex_unlock(&con->sock_mutex);
1152                 msleep(1000);
1153                 lowcomms_connect_sock(con);
1154                 return;
1155         }
1156 out:
1157         mutex_unlock(&con->sock_mutex);
1158         return;
1159 }
1160
1161 static struct socket *tcp_create_listen_sock(struct connection *con,
1162                                              struct sockaddr_storage *saddr)
1163 {
1164         struct socket *sock = NULL;
1165         int result = 0;
1166         int addr_len;
1167
1168         if (dlm_local_addr[0]->ss_family == AF_INET)
1169                 addr_len = sizeof(struct sockaddr_in);
1170         else
1171                 addr_len = sizeof(struct sockaddr_in6);
1172
1173         /* Create a socket to communicate with */
1174         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1175                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1176         if (result < 0) {
1177                 log_print("Can't create listening comms socket");
1178                 goto create_out;
1179         }
1180
1181         sock_set_mark(sock->sk, dlm_config.ci_mark);
1182
1183         /* Turn off Nagle's algorithm */
1184         tcp_sock_set_nodelay(sock->sk);
1185
1186         sock_set_reuseaddr(sock->sk);
1187
1188         write_lock_bh(&sock->sk->sk_callback_lock);
1189         sock->sk->sk_user_data = con;
1190         save_listen_callbacks(sock);
1191         con->rx_action = accept_from_sock;
1192         con->connect_action = tcp_connect_to_sock;
1193         write_unlock_bh(&sock->sk->sk_callback_lock);
1194
1195         /* Bind to our port */
1196         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1197         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1198         if (result < 0) {
1199                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1200                 sock_release(sock);
1201                 sock = NULL;
1202                 con->sock = NULL;
1203                 goto create_out;
1204         }
1205         sock_set_keepalive(sock->sk);
1206
1207         result = sock->ops->listen(sock, 5);
1208         if (result < 0) {
1209                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1210                 sock_release(sock);
1211                 sock = NULL;
1212                 goto create_out;
1213         }
1214
1215 create_out:
1216         return sock;
1217 }
1218
1219 /* Get local addresses */
1220 static void init_local(void)
1221 {
1222         struct sockaddr_storage sas, *addr;
1223         int i;
1224
1225         dlm_local_count = 0;
1226         for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1227                 if (dlm_our_addr(&sas, i))
1228                         break;
1229
1230                 addr = kmemdup(&sas, sizeof(*addr), GFP_NOFS);
1231                 if (!addr)
1232                         break;
1233                 dlm_local_addr[dlm_local_count++] = addr;
1234         }
1235 }
1236
1237 static void deinit_local(void)
1238 {
1239         int i;
1240
1241         for (i = 0; i < dlm_local_count; i++)
1242                 kfree(dlm_local_addr[i]);
1243 }
1244
1245 /* Initialise SCTP socket and bind to all interfaces */
1246 static int sctp_listen_for_all(void)
1247 {
1248         struct socket *sock = NULL;
1249         int result = -EINVAL;
1250         struct connection *con = nodeid2con(0, GFP_NOFS);
1251
1252         if (!con)
1253                 return -ENOMEM;
1254
1255         log_print("Using SCTP for communications");
1256
1257         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1258                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
1259         if (result < 0) {
1260                 log_print("Can't create comms socket, check SCTP is loaded");
1261                 goto out;
1262         }
1263
1264         sock_set_rcvbuf(sock->sk, NEEDED_RMEM);
1265         sock_set_mark(sock->sk, dlm_config.ci_mark);
1266         sctp_sock_set_nodelay(sock->sk);
1267
1268         write_lock_bh(&sock->sk->sk_callback_lock);
1269         /* Init con struct */
1270         sock->sk->sk_user_data = con;
1271         save_listen_callbacks(sock);
1272         con->sock = sock;
1273         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1274         con->rx_action = accept_from_sock;
1275         con->connect_action = sctp_connect_to_sock;
1276
1277         write_unlock_bh(&sock->sk->sk_callback_lock);
1278
1279         /* Bind to all addresses. */
1280         if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
1281                 goto create_delsock;
1282
1283         result = sock->ops->listen(sock, 5);
1284         if (result < 0) {
1285                 log_print("Can't set socket listening");
1286                 goto create_delsock;
1287         }
1288
1289         return 0;
1290
1291 create_delsock:
1292         sock_release(sock);
1293         con->sock = NULL;
1294 out:
1295         return result;
1296 }
1297
1298 static int tcp_listen_for_all(void)
1299 {
1300         struct socket *sock = NULL;
1301         struct connection *con = nodeid2con(0, GFP_NOFS);
1302         int result = -EINVAL;
1303
1304         if (!con)
1305                 return -ENOMEM;
1306
1307         /* We don't support multi-homed hosts */
1308         if (dlm_local_addr[1] != NULL) {
1309                 log_print("TCP protocol can't handle multi-homed hosts, "
1310                           "try SCTP");
1311                 return -EINVAL;
1312         }
1313
1314         log_print("Using TCP for communications");
1315
1316         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1317         if (sock) {
1318                 add_sock(sock, con);
1319                 result = 0;
1320         }
1321         else {
1322                 result = -EADDRINUSE;
1323         }
1324
1325         return result;
1326 }
1327
1328
1329
1330 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1331                                                      gfp_t allocation)
1332 {
1333         struct writequeue_entry *entry;
1334
1335         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1336         if (!entry)
1337                 return NULL;
1338
1339         entry->page = alloc_page(allocation);
1340         if (!entry->page) {
1341                 kfree(entry);
1342                 return NULL;
1343         }
1344
1345         entry->offset = 0;
1346         entry->len = 0;
1347         entry->end = 0;
1348         entry->users = 0;
1349         entry->con = con;
1350
1351         return entry;
1352 }
1353
1354 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1355 {
1356         struct connection *con;
1357         struct writequeue_entry *e;
1358         int offset = 0;
1359
1360         con = nodeid2con(nodeid, allocation);
1361         if (!con)
1362                 return NULL;
1363
1364         spin_lock(&con->writequeue_lock);
1365         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1366         if ((&e->list == &con->writequeue) ||
1367             (PAGE_SIZE - e->end < len)) {
1368                 e = NULL;
1369         } else {
1370                 offset = e->end;
1371                 e->end += len;
1372                 e->users++;
1373         }
1374         spin_unlock(&con->writequeue_lock);
1375
1376         if (e) {
1377         got_one:
1378                 *ppc = page_address(e->page) + offset;
1379                 return e;
1380         }
1381
1382         e = new_writequeue_entry(con, allocation);
1383         if (e) {
1384                 spin_lock(&con->writequeue_lock);
1385                 offset = e->end;
1386                 e->end += len;
1387                 e->users++;
1388                 list_add_tail(&e->list, &con->writequeue);
1389                 spin_unlock(&con->writequeue_lock);
1390                 goto got_one;
1391         }
1392         return NULL;
1393 }
1394
1395 void dlm_lowcomms_commit_buffer(void *mh)
1396 {
1397         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1398         struct connection *con = e->con;
1399         int users;
1400
1401         spin_lock(&con->writequeue_lock);
1402         users = --e->users;
1403         if (users)
1404                 goto out;
1405         e->len = e->end - e->offset;
1406         spin_unlock(&con->writequeue_lock);
1407
1408         queue_work(send_workqueue, &con->swork);
1409         return;
1410
1411 out:
1412         spin_unlock(&con->writequeue_lock);
1413         return;
1414 }
1415
1416 /* Send a message */
1417 static void send_to_sock(struct connection *con)
1418 {
1419         int ret = 0;
1420         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1421         struct writequeue_entry *e;
1422         int len, offset;
1423         int count = 0;
1424
1425         mutex_lock(&con->sock_mutex);
1426         if (con->sock == NULL)
1427                 goto out_connect;
1428
1429         spin_lock(&con->writequeue_lock);
1430         for (;;) {
1431                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1432                                list);
1433                 if ((struct list_head *) e == &con->writequeue)
1434                         break;
1435
1436                 len = e->len;
1437                 offset = e->offset;
1438                 BUG_ON(len == 0 && e->users == 0);
1439                 spin_unlock(&con->writequeue_lock);
1440
1441                 ret = 0;
1442                 if (len) {
1443                         ret = kernel_sendpage(con->sock, e->page, offset, len,
1444                                               msg_flags);
1445                         if (ret == -EAGAIN || ret == 0) {
1446                                 if (ret == -EAGAIN &&
1447                                     test_bit(SOCKWQ_ASYNC_NOSPACE, &con->sock->flags) &&
1448                                     !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1449                                         /* Notify TCP that we're limited by the
1450                                          * application window size.
1451                                          */
1452                                         set_bit(SOCK_NOSPACE, &con->sock->flags);
1453                                         con->sock->sk->sk_write_pending++;
1454                                 }
1455                                 cond_resched();
1456                                 goto out;
1457                         } else if (ret < 0)
1458                                 goto send_error;
1459                 }
1460
1461                 /* Don't starve people filling buffers */
1462                 if (++count >= MAX_SEND_MSG_COUNT) {
1463                         cond_resched();
1464                         count = 0;
1465                 }
1466
1467                 spin_lock(&con->writequeue_lock);
1468                 writequeue_entry_complete(e, ret);
1469         }
1470         spin_unlock(&con->writequeue_lock);
1471 out:
1472         mutex_unlock(&con->sock_mutex);
1473         return;
1474
1475 send_error:
1476         mutex_unlock(&con->sock_mutex);
1477         close_connection(con, false, false, true);
1478         /* Requeue the send work. When the work daemon runs again, it will try
1479            a new connection, then call this function again. */
1480         queue_work(send_workqueue, &con->swork);
1481         return;
1482
1483 out_connect:
1484         mutex_unlock(&con->sock_mutex);
1485         queue_work(send_workqueue, &con->swork);
1486         cond_resched();
1487 }
1488
1489 static void clean_one_writequeue(struct connection *con)
1490 {
1491         struct writequeue_entry *e, *safe;
1492
1493         spin_lock(&con->writequeue_lock);
1494         list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1495                 list_del(&e->list);
1496                 free_entry(e);
1497         }
1498         spin_unlock(&con->writequeue_lock);
1499 }
1500
1501 /* Called from recovery when it knows that a node has
1502    left the cluster */
1503 int dlm_lowcomms_close(int nodeid)
1504 {
1505         struct connection *con;
1506         struct dlm_node_addr *na;
1507
1508         log_print("closing connection to node %d", nodeid);
1509         con = nodeid2con(nodeid, 0);
1510         if (con) {
1511                 set_bit(CF_CLOSE, &con->flags);
1512                 close_connection(con, true, true, true);
1513                 clean_one_writequeue(con);
1514         }
1515
1516         spin_lock(&dlm_node_addrs_spin);
1517         na = find_node_addr(nodeid);
1518         if (na) {
1519                 list_del(&na->list);
1520                 while (na->addr_count--)
1521                         kfree(na->addr[na->addr_count]);
1522                 kfree(na);
1523         }
1524         spin_unlock(&dlm_node_addrs_spin);
1525
1526         return 0;
1527 }
1528
1529 /* Receive workqueue function */
1530 static void process_recv_sockets(struct work_struct *work)
1531 {
1532         struct connection *con = container_of(work, struct connection, rwork);
1533         int err;
1534
1535         clear_bit(CF_READ_PENDING, &con->flags);
1536         do {
1537                 err = con->rx_action(con);
1538         } while (!err);
1539 }
1540
1541 /* Send workqueue function */
1542 static void process_send_sockets(struct work_struct *work)
1543 {
1544         struct connection *con = container_of(work, struct connection, swork);
1545
1546         clear_bit(CF_WRITE_PENDING, &con->flags);
1547         if (con->sock == NULL) /* not mutex protected so check it inside too */
1548                 con->connect_action(con);
1549         if (!list_empty(&con->writequeue))
1550                 send_to_sock(con);
1551 }
1552
1553 static void work_stop(void)
1554 {
1555         if (recv_workqueue)
1556                 destroy_workqueue(recv_workqueue);
1557         if (send_workqueue)
1558                 destroy_workqueue(send_workqueue);
1559 }
1560
1561 static int work_start(void)
1562 {
1563         recv_workqueue = alloc_workqueue("dlm_recv",
1564                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1565         if (!recv_workqueue) {
1566                 log_print("can't start dlm_recv");
1567                 return -ENOMEM;
1568         }
1569
1570         send_workqueue = alloc_workqueue("dlm_send",
1571                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1572         if (!send_workqueue) {
1573                 log_print("can't start dlm_send");
1574                 destroy_workqueue(recv_workqueue);
1575                 return -ENOMEM;
1576         }
1577
1578         return 0;
1579 }
1580
1581 static void _stop_conn(struct connection *con, bool and_other)
1582 {
1583         mutex_lock(&con->sock_mutex);
1584         set_bit(CF_CLOSE, &con->flags);
1585         set_bit(CF_READ_PENDING, &con->flags);
1586         set_bit(CF_WRITE_PENDING, &con->flags);
1587         if (con->sock && con->sock->sk) {
1588                 write_lock_bh(&con->sock->sk->sk_callback_lock);
1589                 con->sock->sk->sk_user_data = NULL;
1590                 write_unlock_bh(&con->sock->sk->sk_callback_lock);
1591         }
1592         if (con->othercon && and_other)
1593                 _stop_conn(con->othercon, false);
1594         mutex_unlock(&con->sock_mutex);
1595 }
1596
1597 static void stop_conn(struct connection *con)
1598 {
1599         _stop_conn(con, true);
1600 }
1601
1602 static void shutdown_conn(struct connection *con)
1603 {
1604         if (con->shutdown_action)
1605                 con->shutdown_action(con);
1606 }
1607
1608 static void free_conn(struct connection *con)
1609 {
1610         close_connection(con, true, true, true);
1611         if (con->othercon)
1612                 kfree_rcu(con->othercon, rcu);
1613         spin_lock(&connections_lock);
1614         hlist_del_rcu(&con->list);
1615         spin_unlock(&connections_lock);
1616         clean_one_writequeue(con);
1617         kfree_rcu(con, rcu);
1618 }
1619
1620 static void work_flush(void)
1621 {
1622         int ok, idx;
1623         int i;
1624         struct connection *con;
1625
1626         do {
1627                 ok = 1;
1628                 foreach_conn(stop_conn);
1629                 if (recv_workqueue)
1630                         flush_workqueue(recv_workqueue);
1631                 if (send_workqueue)
1632                         flush_workqueue(send_workqueue);
1633                 idx = srcu_read_lock(&connections_srcu);
1634                 for (i = 0; i < CONN_HASH_SIZE && ok; i++) {
1635                         hlist_for_each_entry_rcu(con, &connection_hash[i],
1636                                                  list) {
1637                                 ok &= test_bit(CF_READ_PENDING, &con->flags);
1638                                 ok &= test_bit(CF_WRITE_PENDING, &con->flags);
1639                                 if (con->othercon) {
1640                                         ok &= test_bit(CF_READ_PENDING,
1641                                                        &con->othercon->flags);
1642                                         ok &= test_bit(CF_WRITE_PENDING,
1643                                                        &con->othercon->flags);
1644                                 }
1645                         }
1646                 }
1647                 srcu_read_unlock(&connections_srcu, idx);
1648         } while (!ok);
1649 }
1650
1651 void dlm_lowcomms_stop(void)
1652 {
1653         /* Set all the flags to prevent any
1654            socket activity.
1655         */
1656         dlm_allow_conn = 0;
1657
1658         if (recv_workqueue)
1659                 flush_workqueue(recv_workqueue);
1660         if (send_workqueue)
1661                 flush_workqueue(send_workqueue);
1662
1663         foreach_conn(shutdown_conn);
1664         work_flush();
1665         foreach_conn(free_conn);
1666         work_stop();
1667         deinit_local();
1668 }
1669
1670 int dlm_lowcomms_start(void)
1671 {
1672         int error = -EINVAL;
1673         struct connection *con;
1674         int i;
1675
1676         for (i = 0; i < CONN_HASH_SIZE; i++)
1677                 INIT_HLIST_HEAD(&connection_hash[i]);
1678
1679         init_local();
1680         if (!dlm_local_count) {
1681                 error = -ENOTCONN;
1682                 log_print("no local IP address has been set");
1683                 goto fail;
1684         }
1685
1686         error = work_start();
1687         if (error)
1688                 goto fail;
1689
1690         dlm_allow_conn = 1;
1691
1692         /* Start listening */
1693         if (dlm_config.ci_protocol == 0)
1694                 error = tcp_listen_for_all();
1695         else
1696                 error = sctp_listen_for_all();
1697         if (error)
1698                 goto fail_unlisten;
1699
1700         return 0;
1701
1702 fail_unlisten:
1703         dlm_allow_conn = 0;
1704         con = nodeid2con(0,0);
1705         if (con) {
1706                 close_connection(con, false, true, true);
1707                 kfree_rcu(con, rcu);
1708         }
1709 fail:
1710         return error;
1711 }
1712
1713 void dlm_lowcomms_exit(void)
1714 {
1715         struct dlm_node_addr *na, *safe;
1716
1717         spin_lock(&dlm_node_addrs_spin);
1718         list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
1719                 list_del(&na->list);
1720                 while (na->addr_count--)
1721                         kfree(na->addr[na->addr_count]);
1722                 kfree(na);
1723         }
1724         spin_unlock(&dlm_node_addrs_spin);
1725 }