fs/dlm/lowcomms.c

   1 /******************************************************************************
   2 *******************************************************************************
   3 **
   4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
   5 **  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
   6 **
   7 **  This copyrighted material is made available to anyone wishing to use,
   8 **  modify, copy, or redistribute it subject to the terms and conditions
   9 **  of the GNU General Public License v.2.
  10 **
  11 *******************************************************************************
  12 ******************************************************************************/
  13
  14 /*
  15  * lowcomms.c
  16  *
  17  * This is the "low-level" comms layer.
  18  *
  19  * It is responsible for sending/receiving messages
  20  * from other nodes in the cluster.
  21  *
  22  * Cluster nodes are referred to by their nodeids. nodeids are
  23  * simply 32 bit numbers to the locking module - if they need to
  24  * be expanded for the cluster infrastructure then that is its
  25  * responsibility. It is this layer's
  26  * responsibility to resolve these into IP address or
  27  * whatever it needs for inter-node communication.
  28  *
  29  * The comms level is two kernel threads that deal mainly with
  30  * the receiving of messages from other nodes and passing them
  31  * up to the mid-level comms layer (which understands the
  32  * message format) for execution by the locking core, and
  33  * a send thread which does all the setting up of connections
  34  * to remote nodes and the sending of data. Threads are not allowed
  35  * to send their own data because it may cause them to wait in times
  36  * of high load. Also, this way, the sending thread can collect together
  37  * messages bound for one node and send them in one block.
  38  *
  39  * lowcomms will choose to use either TCP or SCTP as its transport layer
  40  * depending on the configuration variable 'protocol'. This should be set
  41  * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
  42  * cluster-wide mechanism as it must be the same on all nodes of the cluster
  43  * for the DLM to function.
  44  *
  45  */
  46
  47 #include <asm/ioctls.h>
  48 #include <net/sock.h>
  49 #include <net/tcp.h>
  50 #include <linux/pagemap.h>
  51 #include <linux/file.h>
  52 #include <linux/mutex.h>
  53 #include <linux/sctp.h>
  54 #include <linux/slab.h>
  55 #include <net/sctp/sctp.h>
  56 #include <net/ipv6.h>
  57
  58 #include "dlm_internal.h"
  59 #include "lowcomms.h"
  60 #include "midcomms.h"
  61 #include "config.h"
  62
  63 #define NEEDED_RMEM (4*1024*1024)
  64 #define CONN_HASH_SIZE 32
  65
  66 /* Number of messages to send before rescheduling */
  67 #define MAX_SEND_MSG_COUNT 25
  68
  69 struct cbuf {
  70         unsigned int base;
  71         unsigned int len;
  72         unsigned int mask;
  73 };
  74
  75 static void cbuf_add(struct cbuf *cb, int n)
  76 {
  77         cb->len += n;
  78 }
  79
  80 static int cbuf_data(struct cbuf *cb)
  81 {
  82         return ((cb->base + cb->len) & cb->mask);
  83 }
  84
  85 static void cbuf_init(struct cbuf *cb, int size)
  86 {
  87         cb->base = cb->len = 0;
  88         cb->mask = size-1;
  89 }
  90
  91 static void cbuf_eat(struct cbuf *cb, int n)
  92 {
  93         cb->len  -= n;
  94         cb->base += n;
  95         cb->base &= cb->mask;
  96 }
  97
  98 static bool cbuf_empty(struct cbuf *cb)
  99 {
 100         return cb->len == 0;
 101 }
 102
 103 struct connection {
 104         struct socket *sock;    /* NULL if not connected */
 105         uint32_t nodeid;        /* So we know who we are in the list */
 106         struct mutex sock_mutex;
 107         unsigned long flags;
 108 #define CF_READ_PENDING 1
 109 #define CF_WRITE_PENDING 2
 110 #define CF_CONNECT_PENDING 3
 111 #define CF_INIT_PENDING 4
 112 #define CF_IS_OTHERCON 5
 113 #define CF_CLOSE 6
 114 #define CF_APP_LIMITED 7
 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         struct page *rx_page;
 120         struct cbuf cb;
 121         int retries;
 122 #define MAX_CONNECT_RETRIES 3
 123         struct hlist_node list;
 124         struct connection *othercon;
 125         struct work_struct rwork; /* Receive workqueue */
 126         struct work_struct swork; /* Send workqueue */
 127 };
 128 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
 129
 130 /* An entry waiting to be sent */
 131 struct writequeue_entry {
 132         struct list_head list;
 133         struct page *page;
 134         int offset;
 135         int len;
 136         int end;
 137         int users;
 138         struct connection *con;
 139 };
 140
 141 struct dlm_node_addr {
 142         struct list_head list;
 143         int nodeid;
 144         int addr_count;
 145         int curr_addr_index;
 146         struct sockaddr_storage *addr[DLM_MAX_ADDR_COUNT];
 147 };
 148
 149 static LIST_HEAD(dlm_node_addrs);
 150 static DEFINE_SPINLOCK(dlm_node_addrs_spin);
 151
 152 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
 153 static int dlm_local_count;
 154 static int dlm_allow_conn;
 155
 156 /* Work queues */
 157 static struct workqueue_struct *recv_workqueue;
 158 static struct workqueue_struct *send_workqueue;
 159
 160 static struct hlist_head connection_hash[CONN_HASH_SIZE];
 161 static DEFINE_MUTEX(connections_lock);
 162 static struct kmem_cache *con_cache;
 163
 164 static void process_recv_sockets(struct work_struct *work);
 165 static void process_send_sockets(struct work_struct *work);
 166
 167
 168 /* This is deliberately very simple because most clusters have simple
 169    sequential nodeids, so we should be able to go straight to a connection
 170    struct in the array */
 171 static inline int nodeid_hash(int nodeid)
 172 {
 173         return nodeid & (CONN_HASH_SIZE-1);
 174 }
 175
 176 static struct connection *__find_con(int nodeid)
 177 {
 178         int r;
 179         struct connection *con;
 180
 181         r = nodeid_hash(nodeid);
 182
 183         hlist_for_each_entry(con, &connection_hash[r], list) {
 184                 if (con->nodeid == nodeid)
 185                         return con;
 186         }
 187         return NULL;
 188 }
 189
 190 /*
 191  * If 'allocation' is zero then we don't attempt to create a new
 192  * connection structure for this node.
 193  */
 194 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
 195 {
 196         struct connection *con = NULL;
 197         int r;
 198
 199         con = __find_con(nodeid);
 200         if (con || !alloc)
 201                 return con;
 202
 203         con = kmem_cache_zalloc(con_cache, alloc);
 204         if (!con)
 205                 return NULL;
 206
 207         r = nodeid_hash(nodeid);
 208         hlist_add_head(&con->list, &connection_hash[r]);
 209
 210         con->nodeid = nodeid;
 211         mutex_init(&con->sock_mutex);
 212         INIT_LIST_HEAD(&con->writequeue);
 213         spin_lock_init(&con->writequeue_lock);
 214         INIT_WORK(&con->swork, process_send_sockets);
 215         INIT_WORK(&con->rwork, process_recv_sockets);
 216
 217         /* Setup action pointers for child sockets */
 218         if (con->nodeid) {
 219                 struct connection *zerocon = __find_con(0);
 220
 221                 con->connect_action = zerocon->connect_action;
 222                 if (!con->rx_action)
 223                         con->rx_action = zerocon->rx_action;
 224         }
 225
 226         return con;
 227 }
 228
 229 /* Loop round all connections */
 230 static void foreach_conn(void (*conn_func)(struct connection *c))
 231 {
 232         int i;
 233         struct hlist_node *n;
 234         struct connection *con;
 235
 236         for (i = 0; i < CONN_HASH_SIZE; i++) {
 237                 hlist_for_each_entry_safe(con, n, &connection_hash[i], list)
 238                         conn_func(con);
 239         }
 240 }
 241
 242 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
 243 {
 244         struct connection *con;
 245
 246         mutex_lock(&connections_lock);
 247         con = __nodeid2con(nodeid, allocation);
 248         mutex_unlock(&connections_lock);
 249
 250         return con;
 251 }
 252
 253 static struct dlm_node_addr *find_node_addr(int nodeid)
 254 {
 255         struct dlm_node_addr *na;
 256
 257         list_for_each_entry(na, &dlm_node_addrs, list) {
 258                 if (na->nodeid == nodeid)
 259                         return na;
 260         }
 261         return NULL;
 262 }
 263
 264 static int addr_compare(struct sockaddr_storage *x, struct sockaddr_storage *y)
 265 {
 266         switch (x->ss_family) {
 267         case AF_INET: {
 268                 struct sockaddr_in *sinx = (struct sockaddr_in *)x;
 269                 struct sockaddr_in *siny = (struct sockaddr_in *)y;
 270                 if (sinx->sin_addr.s_addr != siny->sin_addr.s_addr)
 271                         return 0;
 272                 if (sinx->sin_port != siny->sin_port)
 273                         return 0;
 274                 break;
 275         }
 276         case AF_INET6: {
 277                 struct sockaddr_in6 *sinx = (struct sockaddr_in6 *)x;
 278                 struct sockaddr_in6 *siny = (struct sockaddr_in6 *)y;
 279                 if (!ipv6_addr_equal(&sinx->sin6_addr, &siny->sin6_addr))
 280                         return 0;
 281                 if (sinx->sin6_port != siny->sin6_port)
 282                         return 0;
 283                 break;
 284         }
 285         default:
 286                 return 0;
 287         }
 288         return 1;
 289 }
 290
 291 static int nodeid_to_addr(int nodeid, struct sockaddr_storage *sas_out,
 292                           struct sockaddr *sa_out, bool try_new_addr)
 293 {
 294         struct sockaddr_storage sas;
 295         struct dlm_node_addr *na;
 296
 297         if (!dlm_local_count)
 298                 return -1;
 299
 300         spin_lock(&dlm_node_addrs_spin);
 301         na = find_node_addr(nodeid);
 302         if (na && na->addr_count) {
 303                 memcpy(&sas, na->addr[na->curr_addr_index],
 304                        sizeof(struct sockaddr_storage));
 305
 306                 if (try_new_addr) {
 307                         na->curr_addr_index++;
 308                         if (na->curr_addr_index == na->addr_count)
 309                                 na->curr_addr_index = 0;
 310                 }
 311         }
 312         spin_unlock(&dlm_node_addrs_spin);
 313
 314         if (!na)
 315                 return -EEXIST;
 316
 317         if (!na->addr_count)
 318                 return -ENOENT;
 319
 320         if (sas_out)
 321                 memcpy(sas_out, &sas, sizeof(struct sockaddr_storage));
 322
 323         if (!sa_out)
 324                 return 0;
 325
 326         if (dlm_local_addr[0]->ss_family == AF_INET) {
 327                 struct sockaddr_in *in4  = (struct sockaddr_in *) &sas;
 328                 struct sockaddr_in *ret4 = (struct sockaddr_in *) sa_out;
 329                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
 330         } else {
 331                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &sas;
 332                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) sa_out;
 333                 ret6->sin6_addr = in6->sin6_addr;
 334         }
 335
 336         return 0;
 337 }
 338
 339 static int addr_to_nodeid(struct sockaddr_storage *addr, int *nodeid)
 340 {
 341         struct dlm_node_addr *na;
 342         int rv = -EEXIST;
 343         int addr_i;
 344
 345         spin_lock(&dlm_node_addrs_spin);
 346         list_for_each_entry(na, &dlm_node_addrs, list) {
 347                 if (!na->addr_count)
 348                         continue;
 349
 350                 for (addr_i = 0; addr_i < na->addr_count; addr_i++) {
 351                         if (addr_compare(na->addr[addr_i], addr)) {
 352                                 *nodeid = na->nodeid;
 353                                 rv = 0;
 354                                 goto unlock;
 355                         }
 356                 }
 357         }
 358 unlock:
 359         spin_unlock(&dlm_node_addrs_spin);
 360         return rv;
 361 }
 362
 363 int dlm_lowcomms_addr(int nodeid, struct sockaddr_storage *addr, int len)
 364 {
 365         struct sockaddr_storage *new_addr;
 366         struct dlm_node_addr *new_node, *na;
 367
 368         new_node = kzalloc(sizeof(struct dlm_node_addr), GFP_NOFS);
 369         if (!new_node)
 370                 return -ENOMEM;
 371
 372         new_addr = kzalloc(sizeof(struct sockaddr_storage), GFP_NOFS);
 373         if (!new_addr) {
 374                 kfree(new_node);
 375                 return -ENOMEM;
 376         }
 377
 378         memcpy(new_addr, addr, len);
 379
 380         spin_lock(&dlm_node_addrs_spin);
 381         na = find_node_addr(nodeid);
 382         if (!na) {
 383                 new_node->nodeid = nodeid;
 384                 new_node->addr[0] = new_addr;
 385                 new_node->addr_count = 1;
 386                 list_add(&new_node->list, &dlm_node_addrs);
 387                 spin_unlock(&dlm_node_addrs_spin);
 388                 return 0;
 389         }
 390
 391         if (na->addr_count >= DLM_MAX_ADDR_COUNT) {
 392                 spin_unlock(&dlm_node_addrs_spin);
 393                 kfree(new_addr);
 394                 kfree(new_node);
 395                 return -ENOSPC;
 396         }
 397
 398         na->addr[na->addr_count++] = new_addr;
 399         spin_unlock(&dlm_node_addrs_spin);
 400         kfree(new_node);
 401         return 0;
 402 }
 403
 404 /* Data available on socket or listen socket received a connect */
 405 static void lowcomms_data_ready(struct sock *sk)
 406 {
 407         struct connection *con = sock2con(sk);
 408         if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
 409                 queue_work(recv_workqueue, &con->rwork);
 410 }
 411
 412 static void lowcomms_write_space(struct sock *sk)
 413 {
 414         struct connection *con = sock2con(sk);
 415
 416         if (!con)
 417                 return;
 418
 419         clear_bit(SOCK_NOSPACE, &con->sock->flags);
 420
 421         if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
 422                 con->sock->sk->sk_write_pending--;
 423                 clear_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags);
 424         }
 425
 426         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
 427                 queue_work(send_workqueue, &con->swork);
 428 }
 429
 430 static inline void lowcomms_connect_sock(struct connection *con)
 431 {
 432         if (test_bit(CF_CLOSE, &con->flags))
 433                 return;
 434         if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
 435                 queue_work(send_workqueue, &con->swork);
 436 }
 437
 438 static void lowcomms_state_change(struct sock *sk)
 439 {
 440         /* SCTP layer is not calling sk_data_ready when the connection
 441          * is done, so we catch the signal through here. Also, it
 442          * doesn't switch socket state when entering shutdown, so we
 443          * skip the write in that case.
 444          */
 445         if (sk->sk_shutdown) {
 446                 if (sk->sk_shutdown == RCV_SHUTDOWN)
 447                         lowcomms_data_ready(sk);
 448         } else if (sk->sk_state == TCP_ESTABLISHED) {
 449                 lowcomms_write_space(sk);
 450         }
 451 }
 452
 453 int dlm_lowcomms_connect_node(int nodeid)
 454 {
 455         struct connection *con;
 456
 457         if (nodeid == dlm_our_nodeid())
 458                 return 0;
 459
 460         con = nodeid2con(nodeid, GFP_NOFS);
 461         if (!con)
 462                 return -ENOMEM;
 463         lowcomms_connect_sock(con);
 464         return 0;
 465 }
 466
 467 /* Make a socket active */
 468 static void add_sock(struct socket *sock, struct connection *con)
 469 {
 470         con->sock = sock;
 471
 472         /* Install a data_ready callback */
 473         con->sock->sk->sk_data_ready = lowcomms_data_ready;
 474         con->sock->sk->sk_write_space = lowcomms_write_space;
 475         con->sock->sk->sk_state_change = lowcomms_state_change;
 476         con->sock->sk->sk_user_data = con;
 477         con->sock->sk->sk_allocation = GFP_NOFS;
 478 }
 479
 480 /* Add the port number to an IPv6 or 4 sockaddr and return the address
 481    length */
 482 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
 483                           int *addr_len)
 484 {
 485         saddr->ss_family =  dlm_local_addr[0]->ss_family;
 486         if (saddr->ss_family == AF_INET) {
 487                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
 488                 in4_addr->sin_port = cpu_to_be16(port);
 489                 *addr_len = sizeof(struct sockaddr_in);
 490                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
 491         } else {
 492                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
 493                 in6_addr->sin6_port = cpu_to_be16(port);
 494                 *addr_len = sizeof(struct sockaddr_in6);
 495         }
 496         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
 497 }
 498
 499 /* Close a remote connection and tidy up */
 500 static void close_connection(struct connection *con, bool and_other,
 501                              bool tx, bool rx)
 502 {
 503         clear_bit(CF_CONNECT_PENDING, &con->flags);
 504         clear_bit(CF_WRITE_PENDING, &con->flags);
 505         if (tx && cancel_work_sync(&con->swork))
 506                 log_print("canceled swork for node %d", con->nodeid);
 507         if (rx && cancel_work_sync(&con->rwork))
 508                 log_print("canceled rwork for node %d", con->nodeid);
 509
 510         mutex_lock(&con->sock_mutex);
 511         if (con->sock) {
 512                 sock_release(con->sock);
 513                 con->sock = NULL;
 514         }
 515         if (con->othercon && and_other) {
 516                 /* Will only re-enter once. */
 517                 close_connection(con->othercon, false, true, true);
 518         }
 519         if (con->rx_page) {
 520                 __free_page(con->rx_page);
 521                 con->rx_page = NULL;
 522         }
 523
 524         con->retries = 0;
 525         mutex_unlock(&con->sock_mutex);
 526 }
 527
 528 /* Data received from remote end */
 529 static int receive_from_sock(struct connection *con)
 530 {
 531         int ret = 0;
 532         struct msghdr msg = {};
 533         struct kvec iov[2];
 534         unsigned len;
 535         int r;
 536         int call_again_soon = 0;
 537         int nvec;
 538
 539         mutex_lock(&con->sock_mutex);
 540
 541         if (con->sock == NULL) {
 542                 ret = -EAGAIN;
 543                 goto out_close;
 544         }
 545
 546         if (con->rx_page == NULL) {
 547                 /*
 548                  * This doesn't need to be atomic, but I think it should
 549                  * improve performance if it is.
 550                  */
 551                 con->rx_page = alloc_page(GFP_ATOMIC);
 552                 if (con->rx_page == NULL)
 553                         goto out_resched;
 554                 cbuf_init(&con->cb, PAGE_CACHE_SIZE);
 555         }
 556
 557         /*
 558          * iov[0] is the bit of the circular buffer between the current end
 559          * point (cb.base + cb.len) and the end of the buffer.
 560          */
 561         iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
 562         iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
 563         iov[1].iov_len = 0;
 564         nvec = 1;
 565
 566         /*
 567          * iov[1] is the bit of the circular buffer between the start of the
 568          * buffer and the start of the currently used section (cb.base)
 569          */
 570         if (cbuf_data(&con->cb) >= con->cb.base) {
 571                 iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
 572                 iov[1].iov_len = con->cb.base;
 573                 iov[1].iov_base = page_address(con->rx_page);
 574                 nvec = 2;
 575         }
 576         len = iov[0].iov_len + iov[1].iov_len;
 577
 578         r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
 579                                MSG_DONTWAIT | MSG_NOSIGNAL);
 580         if (ret <= 0)
 581                 goto out_close;
 582         else if (ret == len)
 583                 call_again_soon = 1;
 584
 585         BUG_ON(con->nodeid == 0);
 586
 587         cbuf_add(&con->cb, ret);
 588         ret = dlm_process_incoming_buffer(con->nodeid,
 589                                           page_address(con->rx_page),
 590                                           con->cb.base, con->cb.len,
 591                                           PAGE_CACHE_SIZE);
 592         if (ret == -EBADMSG) {
 593                 log_print("lowcomms: addr=%p, base=%u, len=%u, read=%d",
 594                           page_address(con->rx_page), con->cb.base,
 595                           con->cb.len, r);
 596         }
 597         if (ret < 0)
 598                 goto out_close;
 599         cbuf_eat(&con->cb, ret);
 600
 601         if (cbuf_empty(&con->cb) && !call_again_soon) {
 602                 __free_page(con->rx_page);
 603                 con->rx_page = NULL;
 604         }
 605
 606         if (call_again_soon)
 607                 goto out_resched;
 608         mutex_unlock(&con->sock_mutex);
 609         return 0;
 610
 611 out_resched:
 612         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
 613                 queue_work(recv_workqueue, &con->rwork);
 614         mutex_unlock(&con->sock_mutex);
 615         return -EAGAIN;
 616
 617 out_close:
 618         mutex_unlock(&con->sock_mutex);
 619         if (ret != -EAGAIN) {
 620                 close_connection(con, false, true, false);
 621                 /* Reconnect when there is something to send */
 622         }
 623         /* Don't return success if we really got EOF */
 624         if (ret == 0)
 625                 ret = -EAGAIN;
 626
 627         return ret;
 628 }
 629
 630 /* Listening socket is busy, accept a connection */
 631 static int tcp_accept_from_sock(struct connection *con)
 632 {
 633         int result;
 634         struct sockaddr_storage peeraddr;
 635         struct socket *newsock;
 636         int len;
 637         int nodeid;
 638         struct connection *newcon;
 639         struct connection *addcon;
 640
 641         mutex_lock(&connections_lock);
 642         if (!dlm_allow_conn) {
 643                 mutex_unlock(&connections_lock);
 644                 return -1;
 645         }
 646         mutex_unlock(&connections_lock);
 647
 648         memset(&peeraddr, 0, sizeof(peeraddr));
 649         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
 650                                   SOCK_STREAM, IPPROTO_TCP, &newsock);
 651         if (result < 0)
 652                 return -ENOMEM;
 653
 654         mutex_lock_nested(&con->sock_mutex, 0);
 655
 656         result = -ENOTCONN;
 657         if (con->sock == NULL)
 658                 goto accept_err;
 659
 660         newsock->type = con->sock->type;
 661         newsock->ops = con->sock->ops;
 662
 663         result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
 664         if (result < 0)
 665                 goto accept_err;
 666
 667         /* Get the connected socket's peer */
 668         memset(&peeraddr, 0, sizeof(peeraddr));
 669         if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
 670                                   &len, 2)) {
 671                 result = -ECONNABORTED;
 672                 goto accept_err;
 673         }
 674
 675         /* Get the new node's NODEID */
 676         make_sockaddr(&peeraddr, 0, &len);
 677         if (addr_to_nodeid(&peeraddr, &nodeid)) {
 678                 unsigned char *b=(unsigned char *)&peeraddr;
 679                 log_print("connect from non cluster node");
 680                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
 681                                      b, sizeof(struct sockaddr_storage));
 682                 sock_release(newsock);
 683                 mutex_unlock(&con->sock_mutex);
 684                 return -1;
 685         }
 686
 687         log_print("got connection from %d", nodeid);
 688
 689         /*  Check to see if we already have a connection to this node. This
 690          *  could happen if the two nodes initiate a connection at roughly
 691          *  the same time and the connections cross on the wire.
 692          *  In this case we store the incoming one in "othercon"
 693          */
 694         newcon = nodeid2con(nodeid, GFP_NOFS);
 695         if (!newcon) {
 696                 result = -ENOMEM;
 697                 goto accept_err;
 698         }
 699         mutex_lock_nested(&newcon->sock_mutex, 1);
 700         if (newcon->sock) {
 701                 struct connection *othercon = newcon->othercon;
 702
 703                 if (!othercon) {
 704                         othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
 705                         if (!othercon) {
 706                                 log_print("failed to allocate incoming socket");
 707                                 mutex_unlock(&newcon->sock_mutex);
 708                                 result = -ENOMEM;
 709                                 goto accept_err;
 710                         }
 711                         othercon->nodeid = nodeid;
 712                         othercon->rx_action = receive_from_sock;
 713                         mutex_init(&othercon->sock_mutex);
 714                         INIT_WORK(&othercon->swork, process_send_sockets);
 715                         INIT_WORK(&othercon->rwork, process_recv_sockets);
 716                         set_bit(CF_IS_OTHERCON, &othercon->flags);
 717                 }
 718                 if (!othercon->sock) {
 719                         newcon->othercon = othercon;
 720                         othercon->sock = newsock;
 721                         newsock->sk->sk_user_data = othercon;
 722                         add_sock(newsock, othercon);
 723                         addcon = othercon;
 724                 }
 725                 else {
 726                         printk("Extra connection from node %d attempted\n", nodeid);
 727                         result = -EAGAIN;
 728                         mutex_unlock(&newcon->sock_mutex);
 729                         goto accept_err;
 730                 }
 731         }
 732         else {
 733                 newsock->sk->sk_user_data = newcon;
 734                 newcon->rx_action = receive_from_sock;
 735                 add_sock(newsock, newcon);
 736                 addcon = newcon;
 737         }
 738
 739         mutex_unlock(&newcon->sock_mutex);
 740
 741         /*
 742          * Add it to the active queue in case we got data
 743          * between processing the accept adding the socket
 744          * to the read_sockets list
 745          */
 746         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
 747                 queue_work(recv_workqueue, &addcon->rwork);
 748         mutex_unlock(&con->sock_mutex);
 749
 750         return 0;
 751
 752 accept_err:
 753         mutex_unlock(&con->sock_mutex);
 754         sock_release(newsock);
 755
 756         if (result != -EAGAIN)
 757                 log_print("error accepting connection from node: %d", result);
 758         return result;
 759 }
 760
 761 int sctp_accept_from_sock(struct connection *con)
 762 {
 763         /* Check that the new node is in the lockspace */
 764         struct sctp_prim prim;
 765         int nodeid;
 766         int prim_len, ret;
 767         int addr_len;
 768         struct connection *newcon;
 769         struct connection *addcon;
 770         struct socket *newsock;
 771
 772         mutex_lock(&connections_lock);
 773         if (!dlm_allow_conn) {
 774                 mutex_unlock(&connections_lock);
 775                 return -1;
 776         }
 777         mutex_unlock(&connections_lock);
 778
 779         mutex_lock_nested(&con->sock_mutex, 0);
 780
 781         ret = kernel_accept(con->sock, &newsock, O_NONBLOCK);
 782         if (ret < 0)
 783                 goto accept_err;
 784
 785         memset(&prim, 0, sizeof(struct sctp_prim));
 786         prim_len = sizeof(struct sctp_prim);
 787
 788         ret = kernel_getsockopt(newsock, IPPROTO_SCTP, SCTP_PRIMARY_ADDR,
 789                                 (char *)&prim, &prim_len);
 790         if (ret < 0) {
 791                 log_print("getsockopt/sctp_primary_addr failed: %d", ret);
 792                 goto accept_err;
 793         }
 794
 795         make_sockaddr(&prim.ssp_addr, 0, &addr_len);
 796         if (addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
 797                 unsigned char *b = (unsigned char *)&prim.ssp_addr;
 798
 799                 log_print("reject connect from unknown addr");
 800                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE,
 801                                      b, sizeof(struct sockaddr_storage));
 802                 goto accept_err;
 803         }
 804
 805         newcon = nodeid2con(nodeid, GFP_NOFS);
 806         if (!newcon) {
 807                 ret = -ENOMEM;
 808                 goto accept_err;
 809         }
 810
 811         mutex_lock_nested(&newcon->sock_mutex, 1);
 812
 813         if (newcon->sock) {
 814                 struct connection *othercon = newcon->othercon;
 815
 816                 if (!othercon) {
 817                         othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
 818                         if (!othercon) {
 819                                 log_print("failed to allocate incoming socket");
 820                                 mutex_unlock(&newcon->sock_mutex);
 821                                 ret = -ENOMEM;
 822                                 goto accept_err;
 823                         }
 824                         othercon->nodeid = nodeid;
 825                         othercon->rx_action = receive_from_sock;
 826                         mutex_init(&othercon->sock_mutex);
 827                         INIT_WORK(&othercon->swork, process_send_sockets);
 828                         INIT_WORK(&othercon->rwork, process_recv_sockets);
 829                         set_bit(CF_IS_OTHERCON, &othercon->flags);
 830                 }
 831                 if (!othercon->sock) {
 832                         newcon->othercon = othercon;
 833                         othercon->sock = newsock;
 834                         newsock->sk->sk_user_data = othercon;
 835                         add_sock(newsock, othercon);
 836                         addcon = othercon;
 837                 } else {
 838                         printk("Extra connection from node %d attempted\n", nodeid);
 839                         ret = -EAGAIN;
 840                         mutex_unlock(&newcon->sock_mutex);
 841                         goto accept_err;
 842                 }
 843         } else {
 844                 newsock->sk->sk_user_data = newcon;
 845                 newcon->rx_action = receive_from_sock;
 846                 add_sock(newsock, newcon);
 847                 addcon = newcon;
 848         }
 849
 850         log_print("connected to %d", nodeid);
 851
 852         mutex_unlock(&newcon->sock_mutex);
 853
 854         /*
 855          * Add it to the active queue in case we got data
 856          * between processing the accept adding the socket
 857          * to the read_sockets list
 858          */
 859         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
 860                 queue_work(recv_workqueue, &addcon->rwork);
 861         mutex_unlock(&con->sock_mutex);
 862
 863         return 0;
 864
 865 accept_err:
 866         mutex_unlock(&con->sock_mutex);
 867         if (newsock)
 868                 sock_release(newsock);
 869         if (ret != -EAGAIN)
 870                 log_print("error accepting connection from node: %d", ret);
 871
 872         return ret;
 873 }
 874
 875 static void free_entry(struct writequeue_entry *e)
 876 {
 877         __free_page(e->page);
 878         kfree(e);
 879 }
 880
 881 /*
 882  * writequeue_entry_complete - try to delete and free write queue entry
 883  * @e: write queue entry to try to delete
 884  * @completed: bytes completed
 885  *
 886  * writequeue_lock must be held.
 887  */
 888 static void writequeue_entry_complete(struct writequeue_entry *e, int completed)
 889 {
 890         e->offset += completed;
 891         e->len -= completed;
 892
 893         if (e->len == 0 && e->users == 0) {
 894                 list_del(&e->list);
 895                 free_entry(e);
 896         }
 897 }
 898
 899 /*
 900  * sctp_bind_addrs - bind a SCTP socket to all our addresses
 901  */
 902 static int sctp_bind_addrs(struct connection *con, uint16_t port)
 903 {
 904         struct sockaddr_storage localaddr;
 905         int i, addr_len, result = 0;
 906
 907         for (i = 0; i < dlm_local_count; i++) {
 908                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
 909                 make_sockaddr(&localaddr, port, &addr_len);
 910
 911                 if (!i)
 912                         result = kernel_bind(con->sock,
 913                                              (struct sockaddr *)&localaddr,
 914                                              addr_len);
 915                 else
 916                         result = kernel_setsockopt(con->sock, SOL_SCTP,
 917                                                    SCTP_SOCKOPT_BINDX_ADD,
 918                                                    (char *)&localaddr, addr_len);
 919
 920                 if (result < 0) {
 921                         log_print("Can't bind to %d addr number %d, %d.\n",
 922                                   port, i + 1, result);
 923                         break;
 924                 }
 925         }
 926         return result;
 927 }
 928
 929 /* Initiate an SCTP association.
 930    This is a special case of send_to_sock() in that we don't yet have a
 931    peeled-off socket for this association, so we use the listening socket
 932    and add the primary IP address of the remote node.
 933  */
 934 static void sctp_connect_to_sock(struct connection *con)
 935 {
 936         struct sockaddr_storage daddr;
 937         int one = 1;
 938         int result;
 939         int addr_len;
 940         struct socket *sock;
 941
 942         if (con->nodeid == 0) {
 943                 log_print("attempt to connect sock 0 foiled");
 944                 return;
 945         }
 946
 947         mutex_lock(&con->sock_mutex);
 948
 949         /* Some odd races can cause double-connects, ignore them */
 950         if (con->retries++ > MAX_CONNECT_RETRIES)
 951                 goto out;
 952
 953         if (con->sock) {
 954                 log_print("node %d already connected.", con->nodeid);
 955                 goto out;
 956         }
 957
 958         memset(&daddr, 0, sizeof(daddr));
 959         result = nodeid_to_addr(con->nodeid, &daddr, NULL, true);
 960         if (result < 0) {
 961                 log_print("no address for nodeid %d", con->nodeid);
 962                 goto out;
 963         }
 964
 965         /* Create a socket to communicate with */
 966         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
 967                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
 968         if (result < 0)
 969                 goto socket_err;
 970
 971         sock->sk->sk_user_data = con;
 972         con->rx_action = receive_from_sock;
 973         con->connect_action = sctp_connect_to_sock;
 974         add_sock(sock, con);
 975
 976         /* Bind to all addresses. */
 977         if (sctp_bind_addrs(con, 0))
 978                 goto bind_err;
 979
 980         make_sockaddr(&daddr, dlm_config.ci_tcp_port, &addr_len);
 981
 982         log_print("connecting to %d", con->nodeid);
 983
 984         /* Turn off Nagle's algorithm */
 985         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
 986                           sizeof(one));
 987
 988         result = sock->ops->connect(sock, (struct sockaddr *)&daddr, addr_len,
 989                                    O_NONBLOCK);
 990         if (result == -EINPROGRESS)
 991                 result = 0;
 992         if (result == 0)
 993                 goto out;
 994
 995
 996 bind_err:
 997         con->sock = NULL;
 998         sock_release(sock);
 999
1000 socket_err:
1001         /*
1002          * Some errors are fatal and this list might need adjusting. For other
1003          * errors we try again until the max number of retries is reached.
1004          */
1005         if (result != -EHOSTUNREACH &&
1006             result != -ENETUNREACH &&
1007             result != -ENETDOWN &&
1008             result != -EINVAL &&
1009             result != -EPROTONOSUPPORT) {
1010                 log_print("connect %d try %d error %d", con->nodeid,
1011                           con->retries, result);
1012                 mutex_unlock(&con->sock_mutex);
1013                 msleep(1000);
1014                 clear_bit(CF_CONNECT_PENDING, &con->flags);
1015                 lowcomms_connect_sock(con);
1016                 return;
1017         }
1018
1019 out:
1020         mutex_unlock(&con->sock_mutex);
1021 }
1022
1023 /* Connect a new socket to its peer */
1024 static void tcp_connect_to_sock(struct connection *con)
1025 {
1026         struct sockaddr_storage saddr, src_addr;
1027         int addr_len;
1028         struct socket *sock = NULL;
1029         int one = 1;
1030         int result;
1031
1032         if (con->nodeid == 0) {
1033                 log_print("attempt to connect sock 0 foiled");
1034                 return;
1035         }
1036
1037         mutex_lock(&con->sock_mutex);
1038         if (con->retries++ > MAX_CONNECT_RETRIES)
1039                 goto out;
1040
1041         /* Some odd races can cause double-connects, ignore them */
1042         if (con->sock)
1043                 goto out;
1044
1045         /* Create a socket to communicate with */
1046         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1047                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1048         if (result < 0)
1049                 goto out_err;
1050
1051         memset(&saddr, 0, sizeof(saddr));
1052         result = nodeid_to_addr(con->nodeid, &saddr, NULL, false);
1053         if (result < 0) {
1054                 log_print("no address for nodeid %d", con->nodeid);
1055                 goto out_err;
1056         }
1057
1058         sock->sk->sk_user_data = con;
1059         con->rx_action = receive_from_sock;
1060         con->connect_action = tcp_connect_to_sock;
1061         add_sock(sock, con);
1062
1063         /* Bind to our cluster-known address connecting to avoid
1064            routing problems */
1065         memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
1066         make_sockaddr(&src_addr, 0, &addr_len);
1067         result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
1068                                  addr_len);
1069         if (result < 0) {
1070                 log_print("could not bind for connect: %d", result);
1071                 /* This *may* not indicate a critical error */
1072         }
1073
1074         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
1075
1076         log_print("connecting to %d", con->nodeid);
1077
1078         /* Turn off Nagle's algorithm */
1079         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1080                           sizeof(one));
1081
1082         result = sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
1083                                    O_NONBLOCK);
1084         if (result == -EINPROGRESS)
1085                 result = 0;
1086         if (result == 0)
1087                 goto out;
1088
1089 out_err:
1090         if (con->sock) {
1091                 sock_release(con->sock);
1092                 con->sock = NULL;
1093         } else if (sock) {
1094                 sock_release(sock);
1095         }
1096         /*
1097          * Some errors are fatal and this list might need adjusting. For other
1098          * errors we try again until the max number of retries is reached.
1099          */
1100         if (result != -EHOSTUNREACH &&
1101             result != -ENETUNREACH &&
1102             result != -ENETDOWN &&
1103             result != -EINVAL &&
1104             result != -EPROTONOSUPPORT) {
1105                 log_print("connect %d try %d error %d", con->nodeid,
1106                           con->retries, result);
1107                 mutex_unlock(&con->sock_mutex);
1108                 msleep(1000);
1109                 clear_bit(CF_CONNECT_PENDING, &con->flags);
1110                 lowcomms_connect_sock(con);
1111                 return;
1112         }
1113 out:
1114         mutex_unlock(&con->sock_mutex);
1115         return;
1116 }
1117
1118 static struct socket *tcp_create_listen_sock(struct connection *con,
1119                                              struct sockaddr_storage *saddr)
1120 {
1121         struct socket *sock = NULL;
1122         int result = 0;
1123         int one = 1;
1124         int addr_len;
1125
1126         if (dlm_local_addr[0]->ss_family == AF_INET)
1127                 addr_len = sizeof(struct sockaddr_in);
1128         else
1129                 addr_len = sizeof(struct sockaddr_in6);
1130
1131         /* Create a socket to communicate with */
1132         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1133                                   SOCK_STREAM, IPPROTO_TCP, &sock);
1134         if (result < 0) {
1135                 log_print("Can't create listening comms socket");
1136                 goto create_out;
1137         }
1138
1139         /* Turn off Nagle's algorithm */
1140         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1141                           sizeof(one));
1142
1143         result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1144                                    (char *)&one, sizeof(one));
1145
1146         if (result < 0) {
1147                 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1148         }
1149         con->rx_action = tcp_accept_from_sock;
1150         con->connect_action = tcp_connect_to_sock;
1151
1152         /* Bind to our port */
1153         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1154         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1155         if (result < 0) {
1156                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1157                 sock_release(sock);
1158                 sock = NULL;
1159                 con->sock = NULL;
1160                 goto create_out;
1161         }
1162         result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1163                                  (char *)&one, sizeof(one));
1164         if (result < 0) {
1165                 log_print("Set keepalive failed: %d", result);
1166         }
1167
1168         result = sock->ops->listen(sock, 5);
1169         if (result < 0) {
1170                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1171                 sock_release(sock);
1172                 sock = NULL;
1173                 goto create_out;
1174         }
1175
1176 create_out:
1177         return sock;
1178 }
1179
1180 /* Get local addresses */
1181 static void init_local(void)
1182 {
1183         struct sockaddr_storage sas, *addr;
1184         int i;
1185
1186         dlm_local_count = 0;
1187         for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1188                 if (dlm_our_addr(&sas, i))
1189                         break;
1190
1191                 addr = kmalloc(sizeof(*addr), GFP_NOFS);
1192                 if (!addr)
1193                         break;
1194                 memcpy(addr, &sas, sizeof(*addr));
1195                 dlm_local_addr[dlm_local_count++] = addr;
1196         }
1197 }
1198
1199 /* Initialise SCTP socket and bind to all interfaces */
1200 static int sctp_listen_for_all(void)
1201 {
1202         struct socket *sock = NULL;
1203         int result = -EINVAL;
1204         struct connection *con = nodeid2con(0, GFP_NOFS);
1205         int bufsize = NEEDED_RMEM;
1206         int one = 1;
1207
1208         if (!con)
1209                 return -ENOMEM;
1210
1211         log_print("Using SCTP for communications");
1212
1213         result = sock_create_kern(&init_net, dlm_local_addr[0]->ss_family,
1214                                   SOCK_STREAM, IPPROTO_SCTP, &sock);
1215         if (result < 0) {
1216                 log_print("Can't create comms socket, check SCTP is loaded");
1217                 goto out;
1218         }
1219
1220         result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1221                                  (char *)&bufsize, sizeof(bufsize));
1222         if (result)
1223                 log_print("Error increasing buffer space on socket %d", result);
1224
1225         result = kernel_setsockopt(sock, SOL_SCTP, SCTP_NODELAY, (char *)&one,
1226                                    sizeof(one));
1227         if (result < 0)
1228                 log_print("Could not set SCTP NODELAY error %d\n", result);
1229
1230         /* Init con struct */
1231         sock->sk->sk_user_data = con;
1232         con->sock = sock;
1233         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1234         con->rx_action = sctp_accept_from_sock;
1235         con->connect_action = sctp_connect_to_sock;
1236
1237         /* Bind to all addresses. */
1238         if (sctp_bind_addrs(con, dlm_config.ci_tcp_port))
1239                 goto create_delsock;
1240
1241         result = sock->ops->listen(sock, 5);
1242         if (result < 0) {
1243                 log_print("Can't set socket listening");
1244                 goto create_delsock;
1245         }
1246
1247         return 0;
1248
1249 create_delsock:
1250         sock_release(sock);
1251         con->sock = NULL;
1252 out:
1253         return result;
1254 }
1255
1256 static int tcp_listen_for_all(void)
1257 {
1258         struct socket *sock = NULL;
1259         struct connection *con = nodeid2con(0, GFP_NOFS);
1260         int result = -EINVAL;
1261
1262         if (!con)
1263                 return -ENOMEM;
1264
1265         /* We don't support multi-homed hosts */
1266         if (dlm_local_addr[1] != NULL) {
1267                 log_print("TCP protocol can't handle multi-homed hosts, "
1268                           "try SCTP");
1269                 return -EINVAL;
1270         }
1271
1272         log_print("Using TCP for communications");
1273
1274         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1275         if (sock) {
1276                 add_sock(sock, con);
1277                 result = 0;
1278         }
1279         else {
1280                 result = -EADDRINUSE;
1281         }
1282
1283         return result;
1284 }
1285
1286
1287
1288 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1289                                                      gfp_t allocation)
1290 {
1291         struct writequeue_entry *entry;
1292
1293         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1294         if (!entry)
1295                 return NULL;
1296
1297         entry->page = alloc_page(allocation);
1298         if (!entry->page) {
1299                 kfree(entry);
1300                 return NULL;
1301         }
1302
1303         entry->offset = 0;
1304         entry->len = 0;
1305         entry->end = 0;
1306         entry->users = 0;
1307         entry->con = con;
1308
1309         return entry;
1310 }
1311
1312 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1313 {
1314         struct connection *con;
1315         struct writequeue_entry *e;
1316         int offset = 0;
1317
1318         con = nodeid2con(nodeid, allocation);
1319         if (!con)
1320                 return NULL;
1321
1322         spin_lock(&con->writequeue_lock);
1323         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1324         if ((&e->list == &con->writequeue) ||
1325             (PAGE_CACHE_SIZE - e->end < len)) {
1326                 e = NULL;
1327         } else {
1328                 offset = e->end;
1329                 e->end += len;
1330                 e->users++;
1331         }
1332         spin_unlock(&con->writequeue_lock);
1333
1334         if (e) {
1335         got_one:
1336                 *ppc = page_address(e->page) + offset;
1337                 return e;
1338         }
1339
1340         e = new_writequeue_entry(con, allocation);
1341         if (e) {
1342                 spin_lock(&con->writequeue_lock);
1343                 offset = e->end;
1344                 e->end += len;
1345                 e->users++;
1346                 list_add_tail(&e->list, &con->writequeue);
1347                 spin_unlock(&con->writequeue_lock);
1348                 goto got_one;
1349         }
1350         return NULL;
1351 }
1352
1353 void dlm_lowcomms_commit_buffer(void *mh)
1354 {
1355         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1356         struct connection *con = e->con;
1357         int users;
1358
1359         spin_lock(&con->writequeue_lock);
1360         users = --e->users;
1361         if (users)
1362                 goto out;
1363         e->len = e->end - e->offset;
1364         spin_unlock(&con->writequeue_lock);
1365
1366         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1367                 queue_work(send_workqueue, &con->swork);
1368         }
1369         return;
1370
1371 out:
1372         spin_unlock(&con->writequeue_lock);
1373         return;
1374 }
1375
1376 /* Send a message */
1377 static void send_to_sock(struct connection *con)
1378 {
1379         int ret = 0;
1380         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1381         struct writequeue_entry *e;
1382         int len, offset;
1383         int count = 0;
1384
1385         mutex_lock(&con->sock_mutex);
1386         if (con->sock == NULL)
1387                 goto out_connect;
1388
1389         spin_lock(&con->writequeue_lock);
1390         for (;;) {
1391                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1392                                list);
1393                 if ((struct list_head *) e == &con->writequeue)
1394                         break;
1395
1396                 len = e->len;
1397                 offset = e->offset;
1398                 BUG_ON(len == 0 && e->users == 0);
1399                 spin_unlock(&con->writequeue_lock);
1400
1401                 ret = 0;
1402                 if (len) {
1403                         ret = kernel_sendpage(con->sock, e->page, offset, len,
1404                                               msg_flags);
1405                         if (ret == -EAGAIN || ret == 0) {
1406                                 if (ret == -EAGAIN &&
1407                                     test_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags) &&
1408                                     !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1409                                         /* Notify TCP that we're limited by the
1410                                          * application window size.
1411                                          */
1412                                         set_bit(SOCK_NOSPACE, &con->sock->flags);
1413                                         con->sock->sk->sk_write_pending++;
1414                                 }
1415                                 cond_resched();
1416                                 goto out;
1417                         } else if (ret < 0)
1418                                 goto send_error;
1419                 }
1420
1421                 /* Don't starve people filling buffers */
1422                 if (++count >= MAX_SEND_MSG_COUNT) {
1423                         cond_resched();
1424                         count = 0;
1425                 }
1426
1427                 spin_lock(&con->writequeue_lock);
1428                 writequeue_entry_complete(e, ret);
1429         }
1430         spin_unlock(&con->writequeue_lock);
1431 out:
1432         mutex_unlock(&con->sock_mutex);
1433         return;
1434
1435 send_error:
1436         mutex_unlock(&con->sock_mutex);
1437         close_connection(con, false, false, true);
1438         lowcomms_connect_sock(con);
1439         return;
1440
1441 out_connect:
1442         mutex_unlock(&con->sock_mutex);
1443         lowcomms_connect_sock(con);
1444 }
1445
1446 static void clean_one_writequeue(struct connection *con)
1447 {
1448         struct writequeue_entry *e, *safe;
1449
1450         spin_lock(&con->writequeue_lock);
1451         list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1452                 list_del(&e->list);
1453                 free_entry(e);
1454         }
1455         spin_unlock(&con->writequeue_lock);
1456 }
1457
1458 /* Called from recovery when it knows that a node has
1459    left the cluster */
1460 int dlm_lowcomms_close(int nodeid)
1461 {
1462         struct connection *con;
1463         struct dlm_node_addr *na;
1464
1465         log_print("closing connection to node %d", nodeid);
1466         con = nodeid2con(nodeid, 0);
1467         if (con) {
1468                 set_bit(CF_CLOSE, &con->flags);
1469                 close_connection(con, true, true, true);
1470                 clean_one_writequeue(con);
1471         }
1472
1473         spin_lock(&dlm_node_addrs_spin);
1474         na = find_node_addr(nodeid);
1475         if (na) {
1476                 list_del(&na->list);
1477                 while (na->addr_count--)
1478                         kfree(na->addr[na->addr_count]);
1479                 kfree(na);
1480         }
1481         spin_unlock(&dlm_node_addrs_spin);
1482
1483         return 0;
1484 }
1485
1486 /* Receive workqueue function */
1487 static void process_recv_sockets(struct work_struct *work)
1488 {
1489         struct connection *con = container_of(work, struct connection, rwork);
1490         int err;
1491
1492         clear_bit(CF_READ_PENDING, &con->flags);
1493         do {
1494                 err = con->rx_action(con);
1495         } while (!err);
1496 }
1497
1498 /* Send workqueue function */
1499 static void process_send_sockets(struct work_struct *work)
1500 {
1501         struct connection *con = container_of(work, struct connection, swork);
1502
1503         if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1504                 con->connect_action(con);
1505                 set_bit(CF_WRITE_PENDING, &con->flags);
1506         }
1507         if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags))
1508                 send_to_sock(con);
1509 }
1510
1511
1512 /* Discard all entries on the write queues */
1513 static void clean_writequeues(void)
1514 {
1515         foreach_conn(clean_one_writequeue);
1516 }
1517
1518 static void work_stop(void)
1519 {
1520         destroy_workqueue(recv_workqueue);
1521         destroy_workqueue(send_workqueue);
1522 }
1523
1524 static int work_start(void)
1525 {
1526         recv_workqueue = alloc_workqueue("dlm_recv",
1527                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1528         if (!recv_workqueue) {
1529                 log_print("can't start dlm_recv");
1530                 return -ENOMEM;
1531         }
1532
1533         send_workqueue = alloc_workqueue("dlm_send",
1534                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1535         if (!send_workqueue) {
1536                 log_print("can't start dlm_send");
1537                 destroy_workqueue(recv_workqueue);
1538                 return -ENOMEM;
1539         }
1540
1541         return 0;
1542 }
1543
1544 static void stop_conn(struct connection *con)
1545 {
1546         con->flags |= 0x0F;
1547         if (con->sock && con->sock->sk)
1548                 con->sock->sk->sk_user_data = NULL;
1549 }
1550
1551 static void free_conn(struct connection *con)
1552 {
1553         close_connection(con, true, true, true);
1554         if (con->othercon)
1555                 kmem_cache_free(con_cache, con->othercon);
1556         hlist_del(&con->list);
1557         kmem_cache_free(con_cache, con);
1558 }
1559
1560 void dlm_lowcomms_stop(void)
1561 {
1562         /* Set all the flags to prevent any
1563            socket activity.
1564         */
1565         mutex_lock(&connections_lock);
1566         dlm_allow_conn = 0;
1567         foreach_conn(stop_conn);
1568         mutex_unlock(&connections_lock);
1569
1570         work_stop();
1571
1572         mutex_lock(&connections_lock);
1573         clean_writequeues();
1574
1575         foreach_conn(free_conn);
1576
1577         mutex_unlock(&connections_lock);
1578         kmem_cache_destroy(con_cache);
1579 }
1580
1581 int dlm_lowcomms_start(void)
1582 {
1583         int error = -EINVAL;
1584         struct connection *con;
1585         int i;
1586
1587         for (i = 0; i < CONN_HASH_SIZE; i++)
1588                 INIT_HLIST_HEAD(&connection_hash[i]);
1589
1590         init_local();
1591         if (!dlm_local_count) {
1592                 error = -ENOTCONN;
1593                 log_print("no local IP address has been set");
1594                 goto fail;
1595         }
1596
1597         error = -ENOMEM;
1598         con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1599                                       __alignof__(struct connection), 0,
1600                                       NULL);
1601         if (!con_cache)
1602                 goto fail;
1603
1604         error = work_start();
1605         if (error)
1606                 goto fail_destroy;
1607
1608         dlm_allow_conn = 1;
1609
1610         /* Start listening */
1611         if (dlm_config.ci_protocol == 0)
1612                 error = tcp_listen_for_all();
1613         else
1614                 error = sctp_listen_for_all();
1615         if (error)
1616                 goto fail_unlisten;
1617
1618         return 0;
1619
1620 fail_unlisten:
1621         dlm_allow_conn = 0;
1622         con = nodeid2con(0,0);
1623         if (con) {
1624                 close_connection(con, false, true, true);
1625                 kmem_cache_free(con_cache, con);
1626         }
1627 fail_destroy:
1628         kmem_cache_destroy(con_cache);
1629 fail:
1630         return error;
1631 }
1632
1633 void dlm_lowcomms_exit(void)
1634 {
1635         struct dlm_node_addr *na, *safe;
1636
1637         spin_lock(&dlm_node_addrs_spin);
1638         list_for_each_entry_safe(na, safe, &dlm_node_addrs, list) {
1639                 list_del(&na->list);
1640                 while (na->addr_count--)
1641                         kfree(na->addr[na->addr_count]);
1642                 kfree(na);
1643         }
1644         spin_unlock(&dlm_node_addrs_spin);
1645 }