Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
[linux-2.6] / fs / dlm / lowcomms.c
1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5 **  Copyright (C) 2004-2007 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 it's
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 wither 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 shouldbe 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/idr.h>
52 #include <linux/file.h>
53 #include <linux/sctp.h>
54 #include <net/sctp/user.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
63 struct cbuf {
64         unsigned int base;
65         unsigned int len;
66         unsigned int mask;
67 };
68
69 static void cbuf_add(struct cbuf *cb, int n)
70 {
71         cb->len += n;
72 }
73
74 static int cbuf_data(struct cbuf *cb)
75 {
76         return ((cb->base + cb->len) & cb->mask);
77 }
78
79 static void cbuf_init(struct cbuf *cb, int size)
80 {
81         cb->base = cb->len = 0;
82         cb->mask = size-1;
83 }
84
85 static void cbuf_eat(struct cbuf *cb, int n)
86 {
87         cb->len  -= n;
88         cb->base += n;
89         cb->base &= cb->mask;
90 }
91
92 static bool cbuf_empty(struct cbuf *cb)
93 {
94         return cb->len == 0;
95 }
96
97 struct connection {
98         struct socket *sock;    /* NULL if not connected */
99         uint32_t nodeid;        /* So we know who we are in the list */
100         struct mutex sock_mutex;
101         unsigned long flags;
102 #define CF_READ_PENDING 1
103 #define CF_WRITE_PENDING 2
104 #define CF_CONNECT_PENDING 3
105 #define CF_INIT_PENDING 4
106 #define CF_IS_OTHERCON 5
107         struct list_head writequeue;  /* List of outgoing writequeue_entries */
108         spinlock_t writequeue_lock;
109         int (*rx_action) (struct connection *); /* What to do when active */
110         void (*connect_action) (struct connection *);   /* What to do to connect */
111         struct page *rx_page;
112         struct cbuf cb;
113         int retries;
114 #define MAX_CONNECT_RETRIES 3
115         int sctp_assoc;
116         struct connection *othercon;
117         struct work_struct rwork; /* Receive workqueue */
118         struct work_struct swork; /* Send workqueue */
119 };
120 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
121
122 /* An entry waiting to be sent */
123 struct writequeue_entry {
124         struct list_head list;
125         struct page *page;
126         int offset;
127         int len;
128         int end;
129         int users;
130         struct connection *con;
131 };
132
133 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
134 static int dlm_local_count;
135
136 /* Work queues */
137 static struct workqueue_struct *recv_workqueue;
138 static struct workqueue_struct *send_workqueue;
139
140 static DEFINE_IDR(connections_idr);
141 static DECLARE_MUTEX(connections_lock);
142 static int max_nodeid;
143 static struct kmem_cache *con_cache;
144
145 static void process_recv_sockets(struct work_struct *work);
146 static void process_send_sockets(struct work_struct *work);
147
148 /*
149  * If 'allocation' is zero then we don't attempt to create a new
150  * connection structure for this node.
151  */
152 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
153 {
154         struct connection *con = NULL;
155         int r;
156         int n;
157
158         con = idr_find(&connections_idr, nodeid);
159         if (con || !alloc)
160                 return con;
161
162         r = idr_pre_get(&connections_idr, alloc);
163         if (!r)
164                 return NULL;
165
166         con = kmem_cache_zalloc(con_cache, alloc);
167         if (!con)
168                 return NULL;
169
170         r = idr_get_new_above(&connections_idr, con, nodeid, &n);
171         if (r) {
172                 kmem_cache_free(con_cache, con);
173                 return NULL;
174         }
175
176         if (n != nodeid) {
177                 idr_remove(&connections_idr, n);
178                 kmem_cache_free(con_cache, con);
179                 return NULL;
180         }
181
182         con->nodeid = nodeid;
183         mutex_init(&con->sock_mutex);
184         INIT_LIST_HEAD(&con->writequeue);
185         spin_lock_init(&con->writequeue_lock);
186         INIT_WORK(&con->swork, process_send_sockets);
187         INIT_WORK(&con->rwork, process_recv_sockets);
188
189         /* Setup action pointers for child sockets */
190         if (con->nodeid) {
191                 struct connection *zerocon = idr_find(&connections_idr, 0);
192
193                 con->connect_action = zerocon->connect_action;
194                 if (!con->rx_action)
195                         con->rx_action = zerocon->rx_action;
196         }
197
198         if (nodeid > max_nodeid)
199                 max_nodeid = nodeid;
200
201         return con;
202 }
203
204 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
205 {
206         struct connection *con;
207
208         down(&connections_lock);
209         con = __nodeid2con(nodeid, allocation);
210         up(&connections_lock);
211
212         return con;
213 }
214
215 /* This is a bit drastic, but only called when things go wrong */
216 static struct connection *assoc2con(int assoc_id)
217 {
218         int i;
219         struct connection *con;
220
221         down(&connections_lock);
222         for (i=0; i<=max_nodeid; i++) {
223                 con = __nodeid2con(i, 0);
224                 if (con && con->sctp_assoc == assoc_id) {
225                         up(&connections_lock);
226                         return con;
227                 }
228         }
229         up(&connections_lock);
230         return NULL;
231 }
232
233 static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
234 {
235         struct sockaddr_storage addr;
236         int error;
237
238         if (!dlm_local_count)
239                 return -1;
240
241         error = dlm_nodeid_to_addr(nodeid, &addr);
242         if (error)
243                 return error;
244
245         if (dlm_local_addr[0]->ss_family == AF_INET) {
246                 struct sockaddr_in *in4  = (struct sockaddr_in *) &addr;
247                 struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
248                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
249         } else {
250                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &addr;
251                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
252                 memcpy(&ret6->sin6_addr, &in6->sin6_addr,
253                        sizeof(in6->sin6_addr));
254         }
255
256         return 0;
257 }
258
259 /* Data available on socket or listen socket received a connect */
260 static void lowcomms_data_ready(struct sock *sk, int count_unused)
261 {
262         struct connection *con = sock2con(sk);
263         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
264                 queue_work(recv_workqueue, &con->rwork);
265 }
266
267 static void lowcomms_write_space(struct sock *sk)
268 {
269         struct connection *con = sock2con(sk);
270
271         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
272                 queue_work(send_workqueue, &con->swork);
273 }
274
275 static inline void lowcomms_connect_sock(struct connection *con)
276 {
277         if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
278                 queue_work(send_workqueue, &con->swork);
279 }
280
281 static void lowcomms_state_change(struct sock *sk)
282 {
283         if (sk->sk_state == TCP_ESTABLISHED)
284                 lowcomms_write_space(sk);
285 }
286
287 /* Make a socket active */
288 static int add_sock(struct socket *sock, struct connection *con)
289 {
290         con->sock = sock;
291
292         /* Install a data_ready callback */
293         con->sock->sk->sk_data_ready = lowcomms_data_ready;
294         con->sock->sk->sk_write_space = lowcomms_write_space;
295         con->sock->sk->sk_state_change = lowcomms_state_change;
296         con->sock->sk->sk_user_data = con;
297         return 0;
298 }
299
300 /* Add the port number to an IPv6 or 4 sockaddr and return the address
301    length */
302 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
303                           int *addr_len)
304 {
305         saddr->ss_family =  dlm_local_addr[0]->ss_family;
306         if (saddr->ss_family == AF_INET) {
307                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
308                 in4_addr->sin_port = cpu_to_be16(port);
309                 *addr_len = sizeof(struct sockaddr_in);
310                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
311         } else {
312                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
313                 in6_addr->sin6_port = cpu_to_be16(port);
314                 *addr_len = sizeof(struct sockaddr_in6);
315         }
316 }
317
318 /* Close a remote connection and tidy up */
319 static void close_connection(struct connection *con, bool and_other)
320 {
321         mutex_lock(&con->sock_mutex);
322
323         if (con->sock) {
324                 sock_release(con->sock);
325                 con->sock = NULL;
326         }
327         if (con->othercon && and_other) {
328                 /* Will only re-enter once. */
329                 close_connection(con->othercon, false);
330         }
331         if (con->rx_page) {
332                 __free_page(con->rx_page);
333                 con->rx_page = NULL;
334         }
335         con->retries = 0;
336         mutex_unlock(&con->sock_mutex);
337 }
338
339 /* We only send shutdown messages to nodes that are not part of the cluster */
340 static void sctp_send_shutdown(sctp_assoc_t associd)
341 {
342         static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
343         struct msghdr outmessage;
344         struct cmsghdr *cmsg;
345         struct sctp_sndrcvinfo *sinfo;
346         int ret;
347         struct connection *con;
348
349         con = nodeid2con(0,0);
350         BUG_ON(con == NULL);
351
352         outmessage.msg_name = NULL;
353         outmessage.msg_namelen = 0;
354         outmessage.msg_control = outcmsg;
355         outmessage.msg_controllen = sizeof(outcmsg);
356         outmessage.msg_flags = MSG_EOR;
357
358         cmsg = CMSG_FIRSTHDR(&outmessage);
359         cmsg->cmsg_level = IPPROTO_SCTP;
360         cmsg->cmsg_type = SCTP_SNDRCV;
361         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
362         outmessage.msg_controllen = cmsg->cmsg_len;
363         sinfo = CMSG_DATA(cmsg);
364         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
365
366         sinfo->sinfo_flags |= MSG_EOF;
367         sinfo->sinfo_assoc_id = associd;
368
369         ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
370
371         if (ret != 0)
372                 log_print("send EOF to node failed: %d", ret);
373 }
374
375 /* INIT failed but we don't know which node...
376    restart INIT on all pending nodes */
377 static void sctp_init_failed(void)
378 {
379         int i;
380         struct connection *con;
381
382         down(&connections_lock);
383         for (i=1; i<=max_nodeid; i++) {
384                 con = __nodeid2con(i, 0);
385                 if (!con)
386                         continue;
387                 con->sctp_assoc = 0;
388                 if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
389                         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
390                                 queue_work(send_workqueue, &con->swork);
391                         }
392                 }
393         }
394         up(&connections_lock);
395 }
396
397 /* Something happened to an association */
398 static void process_sctp_notification(struct connection *con,
399                                       struct msghdr *msg, char *buf)
400 {
401         union sctp_notification *sn = (union sctp_notification *)buf;
402
403         if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
404                 switch (sn->sn_assoc_change.sac_state) {
405
406                 case SCTP_COMM_UP:
407                 case SCTP_RESTART:
408                 {
409                         /* Check that the new node is in the lockspace */
410                         struct sctp_prim prim;
411                         int nodeid;
412                         int prim_len, ret;
413                         int addr_len;
414                         struct connection *new_con;
415                         struct file *file;
416                         sctp_peeloff_arg_t parg;
417                         int parglen = sizeof(parg);
418
419                         /*
420                          * We get this before any data for an association.
421                          * We verify that the node is in the cluster and
422                          * then peel off a socket for it.
423                          */
424                         if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
425                                 log_print("COMM_UP for invalid assoc ID %d",
426                                          (int)sn->sn_assoc_change.sac_assoc_id);
427                                 sctp_init_failed();
428                                 return;
429                         }
430                         memset(&prim, 0, sizeof(struct sctp_prim));
431                         prim_len = sizeof(struct sctp_prim);
432                         prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
433
434                         ret = kernel_getsockopt(con->sock,
435                                                 IPPROTO_SCTP,
436                                                 SCTP_PRIMARY_ADDR,
437                                                 (char*)&prim,
438                                                 &prim_len);
439                         if (ret < 0) {
440                                 log_print("getsockopt/sctp_primary_addr on "
441                                           "new assoc %d failed : %d",
442                                           (int)sn->sn_assoc_change.sac_assoc_id,
443                                           ret);
444
445                                 /* Retry INIT later */
446                                 new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
447                                 if (new_con)
448                                         clear_bit(CF_CONNECT_PENDING, &con->flags);
449                                 return;
450                         }
451                         make_sockaddr(&prim.ssp_addr, 0, &addr_len);
452                         if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
453                                 int i;
454                                 unsigned char *b=(unsigned char *)&prim.ssp_addr;
455                                 log_print("reject connect from unknown addr");
456                                 for (i=0; i<sizeof(struct sockaddr_storage);i++)
457                                         printk("%02x ", b[i]);
458                                 printk("\n");
459                                 sctp_send_shutdown(prim.ssp_assoc_id);
460                                 return;
461                         }
462
463                         new_con = nodeid2con(nodeid, GFP_KERNEL);
464                         if (!new_con)
465                                 return;
466
467                         /* Peel off a new sock */
468                         parg.associd = sn->sn_assoc_change.sac_assoc_id;
469                         ret = kernel_getsockopt(con->sock, IPPROTO_SCTP,
470                                                 SCTP_SOCKOPT_PEELOFF,
471                                                 (void *)&parg, &parglen);
472                         if (ret) {
473                                 log_print("Can't peel off a socket for "
474                                           "connection %d to node %d: err=%d\n",
475                                           parg.associd, nodeid, ret);
476                         }
477                         file = fget(parg.sd);
478                         new_con->sock = SOCKET_I(file->f_dentry->d_inode);
479                         add_sock(new_con->sock, new_con);
480                         fput(file);
481                         put_unused_fd(parg.sd);
482
483                         log_print("got new/restarted association %d nodeid %d",
484                                  (int)sn->sn_assoc_change.sac_assoc_id, nodeid);
485
486                         /* Send any pending writes */
487                         clear_bit(CF_CONNECT_PENDING, &new_con->flags);
488                         clear_bit(CF_INIT_PENDING, &con->flags);
489                         if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
490                                 queue_work(send_workqueue, &new_con->swork);
491                         }
492                         if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
493                                 queue_work(recv_workqueue, &new_con->rwork);
494                 }
495                 break;
496
497                 case SCTP_COMM_LOST:
498                 case SCTP_SHUTDOWN_COMP:
499                 {
500                         con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
501                         if (con) {
502                                 con->sctp_assoc = 0;
503                         }
504                 }
505                 break;
506
507                 /* We don't know which INIT failed, so clear the PENDING flags
508                  * on them all.  if assoc_id is zero then it will then try
509                  * again */
510
511                 case SCTP_CANT_STR_ASSOC:
512                 {
513                         log_print("Can't start SCTP association - retrying");
514                         sctp_init_failed();
515                 }
516                 break;
517
518                 default:
519                         log_print("unexpected SCTP assoc change id=%d state=%d",
520                                   (int)sn->sn_assoc_change.sac_assoc_id,
521                                   sn->sn_assoc_change.sac_state);
522                 }
523         }
524 }
525
526 /* Data received from remote end */
527 static int receive_from_sock(struct connection *con)
528 {
529         int ret = 0;
530         struct msghdr msg = {};
531         struct kvec iov[2];
532         unsigned len;
533         int r;
534         int call_again_soon = 0;
535         int nvec;
536         char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
537
538         mutex_lock(&con->sock_mutex);
539
540         if (con->sock == NULL) {
541                 ret = -EAGAIN;
542                 goto out_close;
543         }
544
545         if (con->rx_page == NULL) {
546                 /*
547                  * This doesn't need to be atomic, but I think it should
548                  * improve performance if it is.
549                  */
550                 con->rx_page = alloc_page(GFP_ATOMIC);
551                 if (con->rx_page == NULL)
552                         goto out_resched;
553                 cbuf_init(&con->cb, PAGE_CACHE_SIZE);
554         }
555
556         /* Only SCTP needs these really */
557         memset(&incmsg, 0, sizeof(incmsg));
558         msg.msg_control = incmsg;
559         msg.msg_controllen = sizeof(incmsg);
560
561         /*
562          * iov[0] is the bit of the circular buffer between the current end
563          * point (cb.base + cb.len) and the end of the buffer.
564          */
565         iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
566         iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
567         iov[1].iov_len = 0;
568         nvec = 1;
569
570         /*
571          * iov[1] is the bit of the circular buffer between the start of the
572          * buffer and the start of the currently used section (cb.base)
573          */
574         if (cbuf_data(&con->cb) >= con->cb.base) {
575                 iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
576                 iov[1].iov_len = con->cb.base;
577                 iov[1].iov_base = page_address(con->rx_page);
578                 nvec = 2;
579         }
580         len = iov[0].iov_len + iov[1].iov_len;
581
582         r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
583                                MSG_DONTWAIT | MSG_NOSIGNAL);
584         if (ret <= 0)
585                 goto out_close;
586
587         /* Process SCTP notifications */
588         if (msg.msg_flags & MSG_NOTIFICATION) {
589                 msg.msg_control = incmsg;
590                 msg.msg_controllen = sizeof(incmsg);
591
592                 process_sctp_notification(con, &msg,
593                                 page_address(con->rx_page) + con->cb.base);
594                 mutex_unlock(&con->sock_mutex);
595                 return 0;
596         }
597         BUG_ON(con->nodeid == 0);
598
599         if (ret == len)
600                 call_again_soon = 1;
601         cbuf_add(&con->cb, ret);
602         ret = dlm_process_incoming_buffer(con->nodeid,
603                                           page_address(con->rx_page),
604                                           con->cb.base, con->cb.len,
605                                           PAGE_CACHE_SIZE);
606         if (ret == -EBADMSG) {
607                 log_print("lowcomms: addr=%p, base=%u, len=%u, "
608                           "iov_len=%u, iov_base[0]=%p, read=%d",
609                           page_address(con->rx_page), con->cb.base, con->cb.len,
610                           len, iov[0].iov_base, r);
611         }
612         if (ret < 0)
613                 goto out_close;
614         cbuf_eat(&con->cb, ret);
615
616         if (cbuf_empty(&con->cb) && !call_again_soon) {
617                 __free_page(con->rx_page);
618                 con->rx_page = NULL;
619         }
620
621         if (call_again_soon)
622                 goto out_resched;
623         mutex_unlock(&con->sock_mutex);
624         return 0;
625
626 out_resched:
627         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
628                 queue_work(recv_workqueue, &con->rwork);
629         mutex_unlock(&con->sock_mutex);
630         return -EAGAIN;
631
632 out_close:
633         mutex_unlock(&con->sock_mutex);
634         if (ret != -EAGAIN && !test_bit(CF_IS_OTHERCON, &con->flags)) {
635                 close_connection(con, false);
636                 /* Reconnect when there is something to send */
637         }
638         /* Don't return success if we really got EOF */
639         if (ret == 0)
640                 ret = -EAGAIN;
641
642         return ret;
643 }
644
645 /* Listening socket is busy, accept a connection */
646 static int tcp_accept_from_sock(struct connection *con)
647 {
648         int result;
649         struct sockaddr_storage peeraddr;
650         struct socket *newsock;
651         int len;
652         int nodeid;
653         struct connection *newcon;
654         struct connection *addcon;
655
656         memset(&peeraddr, 0, sizeof(peeraddr));
657         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
658                                   IPPROTO_TCP, &newsock);
659         if (result < 0)
660                 return -ENOMEM;
661
662         mutex_lock_nested(&con->sock_mutex, 0);
663
664         result = -ENOTCONN;
665         if (con->sock == NULL)
666                 goto accept_err;
667
668         newsock->type = con->sock->type;
669         newsock->ops = con->sock->ops;
670
671         result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
672         if (result < 0)
673                 goto accept_err;
674
675         /* Get the connected socket's peer */
676         memset(&peeraddr, 0, sizeof(peeraddr));
677         if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
678                                   &len, 2)) {
679                 result = -ECONNABORTED;
680                 goto accept_err;
681         }
682
683         /* Get the new node's NODEID */
684         make_sockaddr(&peeraddr, 0, &len);
685         if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
686                 log_print("connect from non cluster node");
687                 sock_release(newsock);
688                 mutex_unlock(&con->sock_mutex);
689                 return -1;
690         }
691
692         log_print("got connection from %d", nodeid);
693
694         /*  Check to see if we already have a connection to this node. This
695          *  could happen if the two nodes initiate a connection at roughly
696          *  the same time and the connections cross on the wire.
697          *  In this case we store the incoming one in "othercon"
698          */
699         newcon = nodeid2con(nodeid, GFP_KERNEL);
700         if (!newcon) {
701                 result = -ENOMEM;
702                 goto accept_err;
703         }
704         mutex_lock_nested(&newcon->sock_mutex, 1);
705         if (newcon->sock) {
706                 struct connection *othercon = newcon->othercon;
707
708                 if (!othercon) {
709                         othercon = kmem_cache_zalloc(con_cache, GFP_KERNEL);
710                         if (!othercon) {
711                                 log_print("failed to allocate incoming socket");
712                                 mutex_unlock(&newcon->sock_mutex);
713                                 result = -ENOMEM;
714                                 goto accept_err;
715                         }
716                         othercon->nodeid = nodeid;
717                         othercon->rx_action = receive_from_sock;
718                         mutex_init(&othercon->sock_mutex);
719                         INIT_WORK(&othercon->swork, process_send_sockets);
720                         INIT_WORK(&othercon->rwork, process_recv_sockets);
721                         set_bit(CF_IS_OTHERCON, &othercon->flags);
722                         newcon->othercon = othercon;
723                 }
724                 othercon->sock = newsock;
725                 newsock->sk->sk_user_data = othercon;
726                 add_sock(newsock, othercon);
727                 addcon = othercon;
728         }
729         else {
730                 newsock->sk->sk_user_data = newcon;
731                 newcon->rx_action = receive_from_sock;
732                 add_sock(newsock, newcon);
733                 addcon = newcon;
734         }
735
736         mutex_unlock(&newcon->sock_mutex);
737
738         /*
739          * Add it to the active queue in case we got data
740          * beween processing the accept adding the socket
741          * to the read_sockets list
742          */
743         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
744                 queue_work(recv_workqueue, &addcon->rwork);
745         mutex_unlock(&con->sock_mutex);
746
747         return 0;
748
749 accept_err:
750         mutex_unlock(&con->sock_mutex);
751         sock_release(newsock);
752
753         if (result != -EAGAIN)
754                 log_print("error accepting connection from node: %d", result);
755         return result;
756 }
757
758 static void free_entry(struct writequeue_entry *e)
759 {
760         __free_page(e->page);
761         kfree(e);
762 }
763
764 /* Initiate an SCTP association.
765    This is a special case of send_to_sock() in that we don't yet have a
766    peeled-off socket for this association, so we use the listening socket
767    and add the primary IP address of the remote node.
768  */
769 static void sctp_init_assoc(struct connection *con)
770 {
771         struct sockaddr_storage rem_addr;
772         char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
773         struct msghdr outmessage;
774         struct cmsghdr *cmsg;
775         struct sctp_sndrcvinfo *sinfo;
776         struct connection *base_con;
777         struct writequeue_entry *e;
778         int len, offset;
779         int ret;
780         int addrlen;
781         struct kvec iov[1];
782
783         if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
784                 return;
785
786         if (con->retries++ > MAX_CONNECT_RETRIES)
787                 return;
788
789         log_print("Initiating association with node %d", con->nodeid);
790
791         if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
792                 log_print("no address for nodeid %d", con->nodeid);
793                 return;
794         }
795         base_con = nodeid2con(0, 0);
796         BUG_ON(base_con == NULL);
797
798         make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
799
800         outmessage.msg_name = &rem_addr;
801         outmessage.msg_namelen = addrlen;
802         outmessage.msg_control = outcmsg;
803         outmessage.msg_controllen = sizeof(outcmsg);
804         outmessage.msg_flags = MSG_EOR;
805
806         spin_lock(&con->writequeue_lock);
807         e = list_entry(con->writequeue.next, struct writequeue_entry,
808                        list);
809
810         BUG_ON((struct list_head *) e == &con->writequeue);
811
812         len = e->len;
813         offset = e->offset;
814         spin_unlock(&con->writequeue_lock);
815         kmap(e->page);
816
817         /* Send the first block off the write queue */
818         iov[0].iov_base = page_address(e->page)+offset;
819         iov[0].iov_len = len;
820
821         cmsg = CMSG_FIRSTHDR(&outmessage);
822         cmsg->cmsg_level = IPPROTO_SCTP;
823         cmsg->cmsg_type = SCTP_SNDRCV;
824         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
825         sinfo = CMSG_DATA(cmsg);
826         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
827         sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
828         outmessage.msg_controllen = cmsg->cmsg_len;
829
830         ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
831         if (ret < 0) {
832                 log_print("Send first packet to node %d failed: %d",
833                           con->nodeid, ret);
834
835                 /* Try again later */
836                 clear_bit(CF_CONNECT_PENDING, &con->flags);
837                 clear_bit(CF_INIT_PENDING, &con->flags);
838         }
839         else {
840                 spin_lock(&con->writequeue_lock);
841                 e->offset += ret;
842                 e->len -= ret;
843
844                 if (e->len == 0 && e->users == 0) {
845                         list_del(&e->list);
846                         kunmap(e->page);
847                         free_entry(e);
848                 }
849                 spin_unlock(&con->writequeue_lock);
850         }
851 }
852
853 /* Connect a new socket to its peer */
854 static void tcp_connect_to_sock(struct connection *con)
855 {
856         int result = -EHOSTUNREACH;
857         struct sockaddr_storage saddr;
858         int addr_len;
859         struct socket *sock;
860
861         if (con->nodeid == 0) {
862                 log_print("attempt to connect sock 0 foiled");
863                 return;
864         }
865
866         mutex_lock(&con->sock_mutex);
867         if (con->retries++ > MAX_CONNECT_RETRIES)
868                 goto out;
869
870         /* Some odd races can cause double-connects, ignore them */
871         if (con->sock) {
872                 result = 0;
873                 goto out;
874         }
875
876         /* Create a socket to communicate with */
877         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
878                                   IPPROTO_TCP, &sock);
879         if (result < 0)
880                 goto out_err;
881
882         memset(&saddr, 0, sizeof(saddr));
883         if (dlm_nodeid_to_addr(con->nodeid, &saddr))
884                 goto out_err;
885
886         sock->sk->sk_user_data = con;
887         con->rx_action = receive_from_sock;
888         con->connect_action = tcp_connect_to_sock;
889         add_sock(sock, con);
890
891         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
892
893         log_print("connecting to %d", con->nodeid);
894         result =
895                 sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
896                                    O_NONBLOCK);
897         if (result == -EINPROGRESS)
898                 result = 0;
899         if (result == 0)
900                 goto out;
901
902 out_err:
903         if (con->sock) {
904                 sock_release(con->sock);
905                 con->sock = NULL;
906         }
907         /*
908          * Some errors are fatal and this list might need adjusting. For other
909          * errors we try again until the max number of retries is reached.
910          */
911         if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
912             result != -ENETDOWN && result != EINVAL
913             && result != -EPROTONOSUPPORT) {
914                 lowcomms_connect_sock(con);
915                 result = 0;
916         }
917 out:
918         mutex_unlock(&con->sock_mutex);
919         return;
920 }
921
922 static struct socket *tcp_create_listen_sock(struct connection *con,
923                                              struct sockaddr_storage *saddr)
924 {
925         struct socket *sock = NULL;
926         int result = 0;
927         int one = 1;
928         int addr_len;
929
930         if (dlm_local_addr[0]->ss_family == AF_INET)
931                 addr_len = sizeof(struct sockaddr_in);
932         else
933                 addr_len = sizeof(struct sockaddr_in6);
934
935         /* Create a socket to communicate with */
936         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
937                                   IPPROTO_TCP, &sock);
938         if (result < 0) {
939                 log_print("Can't create listening comms socket");
940                 goto create_out;
941         }
942
943         result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
944                                    (char *)&one, sizeof(one));
945
946         if (result < 0) {
947                 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
948         }
949         sock->sk->sk_user_data = con;
950         con->rx_action = tcp_accept_from_sock;
951         con->connect_action = tcp_connect_to_sock;
952         con->sock = sock;
953
954         /* Bind to our port */
955         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
956         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
957         if (result < 0) {
958                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
959                 sock_release(sock);
960                 sock = NULL;
961                 con->sock = NULL;
962                 goto create_out;
963         }
964         result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
965                                  (char *)&one, sizeof(one));
966         if (result < 0) {
967                 log_print("Set keepalive failed: %d", result);
968         }
969
970         result = sock->ops->listen(sock, 5);
971         if (result < 0) {
972                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
973                 sock_release(sock);
974                 sock = NULL;
975                 goto create_out;
976         }
977
978 create_out:
979         return sock;
980 }
981
982 /* Get local addresses */
983 static void init_local(void)
984 {
985         struct sockaddr_storage sas, *addr;
986         int i;
987
988         dlm_local_count = 0;
989         for (i = 0; i < DLM_MAX_ADDR_COUNT - 1; i++) {
990                 if (dlm_our_addr(&sas, i))
991                         break;
992
993                 addr = kmalloc(sizeof(*addr), GFP_KERNEL);
994                 if (!addr)
995                         break;
996                 memcpy(addr, &sas, sizeof(*addr));
997                 dlm_local_addr[dlm_local_count++] = addr;
998         }
999 }
1000
1001 /* Bind to an IP address. SCTP allows multiple address so it can do
1002    multi-homing */
1003 static int add_sctp_bind_addr(struct connection *sctp_con,
1004                               struct sockaddr_storage *addr,
1005                               int addr_len, int num)
1006 {
1007         int result = 0;
1008
1009         if (num == 1)
1010                 result = kernel_bind(sctp_con->sock,
1011                                      (struct sockaddr *) addr,
1012                                      addr_len);
1013         else
1014                 result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
1015                                            SCTP_SOCKOPT_BINDX_ADD,
1016                                            (char *)addr, addr_len);
1017
1018         if (result < 0)
1019                 log_print("Can't bind to port %d addr number %d",
1020                           dlm_config.ci_tcp_port, num);
1021
1022         return result;
1023 }
1024
1025 /* Initialise SCTP socket and bind to all interfaces */
1026 static int sctp_listen_for_all(void)
1027 {
1028         struct socket *sock = NULL;
1029         struct sockaddr_storage localaddr;
1030         struct sctp_event_subscribe subscribe;
1031         int result = -EINVAL, num = 1, i, addr_len;
1032         struct connection *con = nodeid2con(0, GFP_KERNEL);
1033         int bufsize = NEEDED_RMEM;
1034
1035         if (!con)
1036                 return -ENOMEM;
1037
1038         log_print("Using SCTP for communications");
1039
1040         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
1041                                   IPPROTO_SCTP, &sock);
1042         if (result < 0) {
1043                 log_print("Can't create comms socket, check SCTP is loaded");
1044                 goto out;
1045         }
1046
1047         /* Listen for events */
1048         memset(&subscribe, 0, sizeof(subscribe));
1049         subscribe.sctp_data_io_event = 1;
1050         subscribe.sctp_association_event = 1;
1051         subscribe.sctp_send_failure_event = 1;
1052         subscribe.sctp_shutdown_event = 1;
1053         subscribe.sctp_partial_delivery_event = 1;
1054
1055         result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1056                                  (char *)&bufsize, sizeof(bufsize));
1057         if (result)
1058                 log_print("Error increasing buffer space on socket %d", result);
1059
1060         result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
1061                                    (char *)&subscribe, sizeof(subscribe));
1062         if (result < 0) {
1063                 log_print("Failed to set SCTP_EVENTS on socket: result=%d",
1064                           result);
1065                 goto create_delsock;
1066         }
1067
1068         /* Init con struct */
1069         sock->sk->sk_user_data = con;
1070         con->sock = sock;
1071         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1072         con->rx_action = receive_from_sock;
1073         con->connect_action = sctp_init_assoc;
1074
1075         /* Bind to all interfaces. */
1076         for (i = 0; i < dlm_local_count; i++) {
1077                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1078                 make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
1079
1080                 result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
1081                 if (result)
1082                         goto create_delsock;
1083                 ++num;
1084         }
1085
1086         result = sock->ops->listen(sock, 5);
1087         if (result < 0) {
1088                 log_print("Can't set socket listening");
1089                 goto create_delsock;
1090         }
1091
1092         return 0;
1093
1094 create_delsock:
1095         sock_release(sock);
1096         con->sock = NULL;
1097 out:
1098         return result;
1099 }
1100
1101 static int tcp_listen_for_all(void)
1102 {
1103         struct socket *sock = NULL;
1104         struct connection *con = nodeid2con(0, GFP_KERNEL);
1105         int result = -EINVAL;
1106
1107         if (!con)
1108                 return -ENOMEM;
1109
1110         /* We don't support multi-homed hosts */
1111         if (dlm_local_addr[1] != NULL) {
1112                 log_print("TCP protocol can't handle multi-homed hosts, "
1113                           "try SCTP");
1114                 return -EINVAL;
1115         }
1116
1117         log_print("Using TCP for communications");
1118
1119         set_bit(CF_IS_OTHERCON, &con->flags);
1120
1121         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1122         if (sock) {
1123                 add_sock(sock, con);
1124                 result = 0;
1125         }
1126         else {
1127                 result = -EADDRINUSE;
1128         }
1129
1130         return result;
1131 }
1132
1133
1134
1135 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1136                                                      gfp_t allocation)
1137 {
1138         struct writequeue_entry *entry;
1139
1140         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1141         if (!entry)
1142                 return NULL;
1143
1144         entry->page = alloc_page(allocation);
1145         if (!entry->page) {
1146                 kfree(entry);
1147                 return NULL;
1148         }
1149
1150         entry->offset = 0;
1151         entry->len = 0;
1152         entry->end = 0;
1153         entry->users = 0;
1154         entry->con = con;
1155
1156         return entry;
1157 }
1158
1159 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1160 {
1161         struct connection *con;
1162         struct writequeue_entry *e;
1163         int offset = 0;
1164         int users = 0;
1165
1166         con = nodeid2con(nodeid, allocation);
1167         if (!con)
1168                 return NULL;
1169
1170         spin_lock(&con->writequeue_lock);
1171         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1172         if ((&e->list == &con->writequeue) ||
1173             (PAGE_CACHE_SIZE - e->end < len)) {
1174                 e = NULL;
1175         } else {
1176                 offset = e->end;
1177                 e->end += len;
1178                 users = e->users++;
1179         }
1180         spin_unlock(&con->writequeue_lock);
1181
1182         if (e) {
1183         got_one:
1184                 if (users == 0)
1185                         kmap(e->page);
1186                 *ppc = page_address(e->page) + offset;
1187                 return e;
1188         }
1189
1190         e = new_writequeue_entry(con, allocation);
1191         if (e) {
1192                 spin_lock(&con->writequeue_lock);
1193                 offset = e->end;
1194                 e->end += len;
1195                 users = e->users++;
1196                 list_add_tail(&e->list, &con->writequeue);
1197                 spin_unlock(&con->writequeue_lock);
1198                 goto got_one;
1199         }
1200         return NULL;
1201 }
1202
1203 void dlm_lowcomms_commit_buffer(void *mh)
1204 {
1205         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1206         struct connection *con = e->con;
1207         int users;
1208
1209         spin_lock(&con->writequeue_lock);
1210         users = --e->users;
1211         if (users)
1212                 goto out;
1213         e->len = e->end - e->offset;
1214         kunmap(e->page);
1215         spin_unlock(&con->writequeue_lock);
1216
1217         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1218                 queue_work(send_workqueue, &con->swork);
1219         }
1220         return;
1221
1222 out:
1223         spin_unlock(&con->writequeue_lock);
1224         return;
1225 }
1226
1227 /* Send a message */
1228 static void send_to_sock(struct connection *con)
1229 {
1230         int ret = 0;
1231         ssize_t(*sendpage) (struct socket *, struct page *, int, size_t, int);
1232         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1233         struct writequeue_entry *e;
1234         int len, offset;
1235
1236         mutex_lock(&con->sock_mutex);
1237         if (con->sock == NULL)
1238                 goto out_connect;
1239
1240         sendpage = con->sock->ops->sendpage;
1241
1242         spin_lock(&con->writequeue_lock);
1243         for (;;) {
1244                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1245                                list);
1246                 if ((struct list_head *) e == &con->writequeue)
1247                         break;
1248
1249                 len = e->len;
1250                 offset = e->offset;
1251                 BUG_ON(len == 0 && e->users == 0);
1252                 spin_unlock(&con->writequeue_lock);
1253                 kmap(e->page);
1254
1255                 ret = 0;
1256                 if (len) {
1257                         ret = sendpage(con->sock, e->page, offset, len,
1258                                        msg_flags);
1259                         if (ret == -EAGAIN || ret == 0)
1260                                 goto out;
1261                         if (ret <= 0)
1262                                 goto send_error;
1263                 } else {
1264                         /* Don't starve people filling buffers */
1265                         cond_resched();
1266                 }
1267
1268                 spin_lock(&con->writequeue_lock);
1269                 e->offset += ret;
1270                 e->len -= ret;
1271
1272                 if (e->len == 0 && e->users == 0) {
1273                         list_del(&e->list);
1274                         kunmap(e->page);
1275                         free_entry(e);
1276                         continue;
1277                 }
1278         }
1279         spin_unlock(&con->writequeue_lock);
1280 out:
1281         mutex_unlock(&con->sock_mutex);
1282         return;
1283
1284 send_error:
1285         mutex_unlock(&con->sock_mutex);
1286         close_connection(con, false);
1287         lowcomms_connect_sock(con);
1288         return;
1289
1290 out_connect:
1291         mutex_unlock(&con->sock_mutex);
1292         if (!test_bit(CF_INIT_PENDING, &con->flags))
1293                 lowcomms_connect_sock(con);
1294         return;
1295 }
1296
1297 static void clean_one_writequeue(struct connection *con)
1298 {
1299         struct list_head *list;
1300         struct list_head *temp;
1301
1302         spin_lock(&con->writequeue_lock);
1303         list_for_each_safe(list, temp, &con->writequeue) {
1304                 struct writequeue_entry *e =
1305                         list_entry(list, struct writequeue_entry, list);
1306                 list_del(&e->list);
1307                 free_entry(e);
1308         }
1309         spin_unlock(&con->writequeue_lock);
1310 }
1311
1312 /* Called from recovery when it knows that a node has
1313    left the cluster */
1314 int dlm_lowcomms_close(int nodeid)
1315 {
1316         struct connection *con;
1317
1318         log_print("closing connection to node %d", nodeid);
1319         con = nodeid2con(nodeid, 0);
1320         if (con) {
1321                 clean_one_writequeue(con);
1322                 close_connection(con, true);
1323         }
1324         return 0;
1325 }
1326
1327 /* Receive workqueue function */
1328 static void process_recv_sockets(struct work_struct *work)
1329 {
1330         struct connection *con = container_of(work, struct connection, rwork);
1331         int err;
1332
1333         clear_bit(CF_READ_PENDING, &con->flags);
1334         do {
1335                 err = con->rx_action(con);
1336         } while (!err);
1337 }
1338
1339 /* Send workqueue function */
1340 static void process_send_sockets(struct work_struct *work)
1341 {
1342         struct connection *con = container_of(work, struct connection, swork);
1343
1344         if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1345                 con->connect_action(con);
1346         }
1347         clear_bit(CF_WRITE_PENDING, &con->flags);
1348         send_to_sock(con);
1349 }
1350
1351
1352 /* Discard all entries on the write queues */
1353 static void clean_writequeues(void)
1354 {
1355         int nodeid;
1356
1357         for (nodeid = 1; nodeid <= max_nodeid; nodeid++) {
1358                 struct connection *con = __nodeid2con(nodeid, 0);
1359
1360                 if (con)
1361                         clean_one_writequeue(con);
1362         }
1363 }
1364
1365 static void work_stop(void)
1366 {
1367         destroy_workqueue(recv_workqueue);
1368         destroy_workqueue(send_workqueue);
1369 }
1370
1371 static int work_start(void)
1372 {
1373         int error;
1374         recv_workqueue = create_workqueue("dlm_recv");
1375         error = IS_ERR(recv_workqueue);
1376         if (error) {
1377                 log_print("can't start dlm_recv %d", error);
1378                 return error;
1379         }
1380
1381         send_workqueue = create_singlethread_workqueue("dlm_send");
1382         error = IS_ERR(send_workqueue);
1383         if (error) {
1384                 log_print("can't start dlm_send %d", error);
1385                 destroy_workqueue(recv_workqueue);
1386                 return error;
1387         }
1388
1389         return 0;
1390 }
1391
1392 void dlm_lowcomms_stop(void)
1393 {
1394         int i;
1395         struct connection *con;
1396
1397         /* Set all the flags to prevent any
1398            socket activity.
1399         */
1400         down(&connections_lock);
1401         for (i = 0; i <= max_nodeid; i++) {
1402                 con = __nodeid2con(i, 0);
1403                 if (con)
1404                         con->flags |= 0xFF;
1405         }
1406         up(&connections_lock);
1407
1408         work_stop();
1409
1410         down(&connections_lock);
1411         clean_writequeues();
1412
1413         for (i = 0; i <= max_nodeid; i++) {
1414                 con = __nodeid2con(i, 0);
1415                 if (con) {
1416                         close_connection(con, true);
1417                         if (con->othercon)
1418                                 kmem_cache_free(con_cache, con->othercon);
1419                         kmem_cache_free(con_cache, con);
1420                 }
1421         }
1422         max_nodeid = 0;
1423         up(&connections_lock);
1424         kmem_cache_destroy(con_cache);
1425         idr_init(&connections_idr);
1426 }
1427
1428 int dlm_lowcomms_start(void)
1429 {
1430         int error = -EINVAL;
1431         struct connection *con;
1432
1433         init_local();
1434         if (!dlm_local_count) {
1435                 error = -ENOTCONN;
1436                 log_print("no local IP address has been set");
1437                 goto out;
1438         }
1439
1440         error = -ENOMEM;
1441         con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1442                                       __alignof__(struct connection), 0,
1443                                       NULL, NULL);
1444         if (!con_cache)
1445                 goto out;
1446
1447         /* Set some sysctl minima */
1448         if (sysctl_rmem_max < NEEDED_RMEM)
1449                 sysctl_rmem_max = NEEDED_RMEM;
1450
1451         /* Start listening */
1452         if (dlm_config.ci_protocol == 0)
1453                 error = tcp_listen_for_all();
1454         else
1455                 error = sctp_listen_for_all();
1456         if (error)
1457                 goto fail_unlisten;
1458
1459         error = work_start();
1460         if (error)
1461                 goto fail_unlisten;
1462
1463         return 0;
1464
1465 fail_unlisten:
1466         con = nodeid2con(0,0);
1467         if (con) {
1468                 close_connection(con, false);
1469                 kmem_cache_free(con_cache, con);
1470         }
1471         kmem_cache_destroy(con_cache);
1472
1473 out:
1474         return error;
1475 }