dlm: release socket on error
[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/mutex.h>
54 #include <linux/sctp.h>
55 #include <net/sctp/user.h>
56
57 #include "dlm_internal.h"
58 #include "lowcomms.h"
59 #include "midcomms.h"
60 #include "config.h"
61
62 #define NEEDED_RMEM (4*1024*1024)
63
64 struct cbuf {
65         unsigned int base;
66         unsigned int len;
67         unsigned int mask;
68 };
69
70 static void cbuf_add(struct cbuf *cb, int n)
71 {
72         cb->len += n;
73 }
74
75 static int cbuf_data(struct cbuf *cb)
76 {
77         return ((cb->base + cb->len) & cb->mask);
78 }
79
80 static void cbuf_init(struct cbuf *cb, int size)
81 {
82         cb->base = cb->len = 0;
83         cb->mask = size-1;
84 }
85
86 static void cbuf_eat(struct cbuf *cb, int n)
87 {
88         cb->len  -= n;
89         cb->base += n;
90         cb->base &= cb->mask;
91 }
92
93 static bool cbuf_empty(struct cbuf *cb)
94 {
95         return cb->len == 0;
96 }
97
98 struct connection {
99         struct socket *sock;    /* NULL if not connected */
100         uint32_t nodeid;        /* So we know who we are in the list */
101         struct mutex sock_mutex;
102         unsigned long flags;
103 #define CF_READ_PENDING 1
104 #define CF_WRITE_PENDING 2
105 #define CF_CONNECT_PENDING 3
106 #define CF_INIT_PENDING 4
107 #define CF_IS_OTHERCON 5
108         struct list_head writequeue;  /* List of outgoing writequeue_entries */
109         spinlock_t writequeue_lock;
110         int (*rx_action) (struct connection *); /* What to do when active */
111         void (*connect_action) (struct connection *);   /* What to do to connect */
112         struct page *rx_page;
113         struct cbuf cb;
114         int retries;
115 #define MAX_CONNECT_RETRIES 3
116         int sctp_assoc;
117         struct connection *othercon;
118         struct work_struct rwork; /* Receive workqueue */
119         struct work_struct swork; /* Send workqueue */
120 };
121 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
122
123 /* An entry waiting to be sent */
124 struct writequeue_entry {
125         struct list_head list;
126         struct page *page;
127         int offset;
128         int len;
129         int end;
130         int users;
131         struct connection *con;
132 };
133
134 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
135 static int dlm_local_count;
136
137 /* Work queues */
138 static struct workqueue_struct *recv_workqueue;
139 static struct workqueue_struct *send_workqueue;
140
141 static DEFINE_IDR(connections_idr);
142 static DEFINE_MUTEX(connections_lock);
143 static int max_nodeid;
144 static struct kmem_cache *con_cache;
145
146 static void process_recv_sockets(struct work_struct *work);
147 static void process_send_sockets(struct work_struct *work);
148
149 /*
150  * If 'allocation' is zero then we don't attempt to create a new
151  * connection structure for this node.
152  */
153 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
154 {
155         struct connection *con = NULL;
156         int r;
157         int n;
158
159         con = idr_find(&connections_idr, nodeid);
160         if (con || !alloc)
161                 return con;
162
163         r = idr_pre_get(&connections_idr, alloc);
164         if (!r)
165                 return NULL;
166
167         con = kmem_cache_zalloc(con_cache, alloc);
168         if (!con)
169                 return NULL;
170
171         r = idr_get_new_above(&connections_idr, con, nodeid, &n);
172         if (r) {
173                 kmem_cache_free(con_cache, con);
174                 return NULL;
175         }
176
177         if (n != nodeid) {
178                 idr_remove(&connections_idr, n);
179                 kmem_cache_free(con_cache, con);
180                 return NULL;
181         }
182
183         con->nodeid = nodeid;
184         mutex_init(&con->sock_mutex);
185         INIT_LIST_HEAD(&con->writequeue);
186         spin_lock_init(&con->writequeue_lock);
187         INIT_WORK(&con->swork, process_send_sockets);
188         INIT_WORK(&con->rwork, process_recv_sockets);
189
190         /* Setup action pointers for child sockets */
191         if (con->nodeid) {
192                 struct connection *zerocon = idr_find(&connections_idr, 0);
193
194                 con->connect_action = zerocon->connect_action;
195                 if (!con->rx_action)
196                         con->rx_action = zerocon->rx_action;
197         }
198
199         if (nodeid > max_nodeid)
200                 max_nodeid = nodeid;
201
202         return con;
203 }
204
205 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
206 {
207         struct connection *con;
208
209         mutex_lock(&connections_lock);
210         con = __nodeid2con(nodeid, allocation);
211         mutex_unlock(&connections_lock);
212
213         return con;
214 }
215
216 /* This is a bit drastic, but only called when things go wrong */
217 static struct connection *assoc2con(int assoc_id)
218 {
219         int i;
220         struct connection *con;
221
222         mutex_lock(&connections_lock);
223         for (i=0; i<=max_nodeid; i++) {
224                 con = __nodeid2con(i, 0);
225                 if (con && con->sctp_assoc == assoc_id) {
226                         mutex_unlock(&connections_lock);
227                         return con;
228                 }
229         }
230         mutex_unlock(&connections_lock);
231         return NULL;
232 }
233
234 static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
235 {
236         struct sockaddr_storage addr;
237         int error;
238
239         if (!dlm_local_count)
240                 return -1;
241
242         error = dlm_nodeid_to_addr(nodeid, &addr);
243         if (error)
244                 return error;
245
246         if (dlm_local_addr[0]->ss_family == AF_INET) {
247                 struct sockaddr_in *in4  = (struct sockaddr_in *) &addr;
248                 struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
249                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
250         } else {
251                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &addr;
252                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
253                 memcpy(&ret6->sin6_addr, &in6->sin6_addr,
254                        sizeof(in6->sin6_addr));
255         }
256
257         return 0;
258 }
259
260 /* Data available on socket or listen socket received a connect */
261 static void lowcomms_data_ready(struct sock *sk, int count_unused)
262 {
263         struct connection *con = sock2con(sk);
264         if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
265                 queue_work(recv_workqueue, &con->rwork);
266 }
267
268 static void lowcomms_write_space(struct sock *sk)
269 {
270         struct connection *con = sock2con(sk);
271
272         if (con && !test_and_set_bit(CF_WRITE_PENDING, &con->flags))
273                 queue_work(send_workqueue, &con->swork);
274 }
275
276 static inline void lowcomms_connect_sock(struct connection *con)
277 {
278         if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
279                 queue_work(send_workqueue, &con->swork);
280 }
281
282 static void lowcomms_state_change(struct sock *sk)
283 {
284         if (sk->sk_state == TCP_ESTABLISHED)
285                 lowcomms_write_space(sk);
286 }
287
288 /* Make a socket active */
289 static int add_sock(struct socket *sock, struct connection *con)
290 {
291         con->sock = sock;
292
293         /* Install a data_ready callback */
294         con->sock->sk->sk_data_ready = lowcomms_data_ready;
295         con->sock->sk->sk_write_space = lowcomms_write_space;
296         con->sock->sk->sk_state_change = lowcomms_state_change;
297         con->sock->sk->sk_user_data = con;
298         return 0;
299 }
300
301 /* Add the port number to an IPv6 or 4 sockaddr and return the address
302    length */
303 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
304                           int *addr_len)
305 {
306         saddr->ss_family =  dlm_local_addr[0]->ss_family;
307         if (saddr->ss_family == AF_INET) {
308                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
309                 in4_addr->sin_port = cpu_to_be16(port);
310                 *addr_len = sizeof(struct sockaddr_in);
311                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
312         } else {
313                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
314                 in6_addr->sin6_port = cpu_to_be16(port);
315                 *addr_len = sizeof(struct sockaddr_in6);
316         }
317         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
318 }
319
320 /* Close a remote connection and tidy up */
321 static void close_connection(struct connection *con, bool and_other)
322 {
323         mutex_lock(&con->sock_mutex);
324
325         if (con->sock) {
326                 sock_release(con->sock);
327                 con->sock = NULL;
328         }
329         if (con->othercon && and_other) {
330                 /* Will only re-enter once. */
331                 close_connection(con->othercon, false);
332         }
333         if (con->rx_page) {
334                 __free_page(con->rx_page);
335                 con->rx_page = NULL;
336         }
337
338         con->retries = 0;
339         mutex_unlock(&con->sock_mutex);
340 }
341
342 /* We only send shutdown messages to nodes that are not part of the cluster */
343 static void sctp_send_shutdown(sctp_assoc_t associd)
344 {
345         static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
346         struct msghdr outmessage;
347         struct cmsghdr *cmsg;
348         struct sctp_sndrcvinfo *sinfo;
349         int ret;
350         struct connection *con;
351
352         con = nodeid2con(0,0);
353         BUG_ON(con == NULL);
354
355         outmessage.msg_name = NULL;
356         outmessage.msg_namelen = 0;
357         outmessage.msg_control = outcmsg;
358         outmessage.msg_controllen = sizeof(outcmsg);
359         outmessage.msg_flags = MSG_EOR;
360
361         cmsg = CMSG_FIRSTHDR(&outmessage);
362         cmsg->cmsg_level = IPPROTO_SCTP;
363         cmsg->cmsg_type = SCTP_SNDRCV;
364         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
365         outmessage.msg_controllen = cmsg->cmsg_len;
366         sinfo = CMSG_DATA(cmsg);
367         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
368
369         sinfo->sinfo_flags |= MSG_EOF;
370         sinfo->sinfo_assoc_id = associd;
371
372         ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
373
374         if (ret != 0)
375                 log_print("send EOF to node failed: %d", ret);
376 }
377
378 /* INIT failed but we don't know which node...
379    restart INIT on all pending nodes */
380 static void sctp_init_failed(void)
381 {
382         int i;
383         struct connection *con;
384
385         mutex_lock(&connections_lock);
386         for (i=1; i<=max_nodeid; i++) {
387                 con = __nodeid2con(i, 0);
388                 if (!con)
389                         continue;
390                 con->sctp_assoc = 0;
391                 if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
392                         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
393                                 queue_work(send_workqueue, &con->swork);
394                         }
395                 }
396         }
397         mutex_unlock(&connections_lock);
398 }
399
400 /* Something happened to an association */
401 static void process_sctp_notification(struct connection *con,
402                                       struct msghdr *msg, char *buf)
403 {
404         union sctp_notification *sn = (union sctp_notification *)buf;
405
406         if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
407                 switch (sn->sn_assoc_change.sac_state) {
408
409                 case SCTP_COMM_UP:
410                 case SCTP_RESTART:
411                 {
412                         /* Check that the new node is in the lockspace */
413                         struct sctp_prim prim;
414                         int nodeid;
415                         int prim_len, ret;
416                         int addr_len;
417                         struct connection *new_con;
418                         struct file *file;
419                         sctp_peeloff_arg_t parg;
420                         int parglen = sizeof(parg);
421
422                         /*
423                          * We get this before any data for an association.
424                          * We verify that the node is in the cluster and
425                          * then peel off a socket for it.
426                          */
427                         if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
428                                 log_print("COMM_UP for invalid assoc ID %d",
429                                          (int)sn->sn_assoc_change.sac_assoc_id);
430                                 sctp_init_failed();
431                                 return;
432                         }
433                         memset(&prim, 0, sizeof(struct sctp_prim));
434                         prim_len = sizeof(struct sctp_prim);
435                         prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
436
437                         ret = kernel_getsockopt(con->sock,
438                                                 IPPROTO_SCTP,
439                                                 SCTP_PRIMARY_ADDR,
440                                                 (char*)&prim,
441                                                 &prim_len);
442                         if (ret < 0) {
443                                 log_print("getsockopt/sctp_primary_addr on "
444                                           "new assoc %d failed : %d",
445                                           (int)sn->sn_assoc_change.sac_assoc_id,
446                                           ret);
447
448                                 /* Retry INIT later */
449                                 new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
450                                 if (new_con)
451                                         clear_bit(CF_CONNECT_PENDING, &con->flags);
452                                 return;
453                         }
454                         make_sockaddr(&prim.ssp_addr, 0, &addr_len);
455                         if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
456                                 int i;
457                                 unsigned char *b=(unsigned char *)&prim.ssp_addr;
458                                 log_print("reject connect from unknown addr");
459                                 for (i=0; i<sizeof(struct sockaddr_storage);i++)
460                                         printk("%02x ", b[i]);
461                                 printk("\n");
462                                 sctp_send_shutdown(prim.ssp_assoc_id);
463                                 return;
464                         }
465
466                         new_con = nodeid2con(nodeid, GFP_KERNEL);
467                         if (!new_con)
468                                 return;
469
470                         /* Peel off a new sock */
471                         parg.associd = sn->sn_assoc_change.sac_assoc_id;
472                         ret = kernel_getsockopt(con->sock, IPPROTO_SCTP,
473                                                 SCTP_SOCKOPT_PEELOFF,
474                                                 (void *)&parg, &parglen);
475                         if (ret) {
476                                 log_print("Can't peel off a socket for "
477                                           "connection %d to node %d: err=%d\n",
478                                           parg.associd, nodeid, ret);
479                         }
480                         file = fget(parg.sd);
481                         new_con->sock = SOCKET_I(file->f_dentry->d_inode);
482                         add_sock(new_con->sock, new_con);
483                         fput(file);
484                         put_unused_fd(parg.sd);
485
486                         log_print("got new/restarted association %d nodeid %d",
487                                  (int)sn->sn_assoc_change.sac_assoc_id, nodeid);
488
489                         /* Send any pending writes */
490                         clear_bit(CF_CONNECT_PENDING, &new_con->flags);
491                         clear_bit(CF_INIT_PENDING, &con->flags);
492                         if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
493                                 queue_work(send_workqueue, &new_con->swork);
494                         }
495                         if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
496                                 queue_work(recv_workqueue, &new_con->rwork);
497                 }
498                 break;
499
500                 case SCTP_COMM_LOST:
501                 case SCTP_SHUTDOWN_COMP:
502                 {
503                         con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
504                         if (con) {
505                                 con->sctp_assoc = 0;
506                         }
507                 }
508                 break;
509
510                 /* We don't know which INIT failed, so clear the PENDING flags
511                  * on them all.  if assoc_id is zero then it will then try
512                  * again */
513
514                 case SCTP_CANT_STR_ASSOC:
515                 {
516                         log_print("Can't start SCTP association - retrying");
517                         sctp_init_failed();
518                 }
519                 break;
520
521                 default:
522                         log_print("unexpected SCTP assoc change id=%d state=%d",
523                                   (int)sn->sn_assoc_change.sac_assoc_id,
524                                   sn->sn_assoc_change.sac_state);
525                 }
526         }
527 }
528
529 /* Data received from remote end */
530 static int receive_from_sock(struct connection *con)
531 {
532         int ret = 0;
533         struct msghdr msg = {};
534         struct kvec iov[2];
535         unsigned len;
536         int r;
537         int call_again_soon = 0;
538         int nvec;
539         char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
540
541         mutex_lock(&con->sock_mutex);
542
543         if (con->sock == NULL) {
544                 ret = -EAGAIN;
545                 goto out_close;
546         }
547
548         if (con->rx_page == NULL) {
549                 /*
550                  * This doesn't need to be atomic, but I think it should
551                  * improve performance if it is.
552                  */
553                 con->rx_page = alloc_page(GFP_ATOMIC);
554                 if (con->rx_page == NULL)
555                         goto out_resched;
556                 cbuf_init(&con->cb, PAGE_CACHE_SIZE);
557         }
558
559         /* Only SCTP needs these really */
560         memset(&incmsg, 0, sizeof(incmsg));
561         msg.msg_control = incmsg;
562         msg.msg_controllen = sizeof(incmsg);
563
564         /*
565          * iov[0] is the bit of the circular buffer between the current end
566          * point (cb.base + cb.len) and the end of the buffer.
567          */
568         iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
569         iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
570         iov[1].iov_len = 0;
571         nvec = 1;
572
573         /*
574          * iov[1] is the bit of the circular buffer between the start of the
575          * buffer and the start of the currently used section (cb.base)
576          */
577         if (cbuf_data(&con->cb) >= con->cb.base) {
578                 iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
579                 iov[1].iov_len = con->cb.base;
580                 iov[1].iov_base = page_address(con->rx_page);
581                 nvec = 2;
582         }
583         len = iov[0].iov_len + iov[1].iov_len;
584
585         r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
586                                MSG_DONTWAIT | MSG_NOSIGNAL);
587         if (ret <= 0)
588                 goto out_close;
589
590         /* Process SCTP notifications */
591         if (msg.msg_flags & MSG_NOTIFICATION) {
592                 msg.msg_control = incmsg;
593                 msg.msg_controllen = sizeof(incmsg);
594
595                 process_sctp_notification(con, &msg,
596                                 page_address(con->rx_page) + con->cb.base);
597                 mutex_unlock(&con->sock_mutex);
598                 return 0;
599         }
600         BUG_ON(con->nodeid == 0);
601
602         if (ret == len)
603                 call_again_soon = 1;
604         cbuf_add(&con->cb, ret);
605         ret = dlm_process_incoming_buffer(con->nodeid,
606                                           page_address(con->rx_page),
607                                           con->cb.base, con->cb.len,
608                                           PAGE_CACHE_SIZE);
609         if (ret == -EBADMSG) {
610                 log_print("lowcomms: addr=%p, base=%u, len=%u, "
611                           "iov_len=%u, iov_base[0]=%p, read=%d",
612                           page_address(con->rx_page), con->cb.base, con->cb.len,
613                           len, iov[0].iov_base, r);
614         }
615         if (ret < 0)
616                 goto out_close;
617         cbuf_eat(&con->cb, ret);
618
619         if (cbuf_empty(&con->cb) && !call_again_soon) {
620                 __free_page(con->rx_page);
621                 con->rx_page = NULL;
622         }
623
624         if (call_again_soon)
625                 goto out_resched;
626         mutex_unlock(&con->sock_mutex);
627         return 0;
628
629 out_resched:
630         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
631                 queue_work(recv_workqueue, &con->rwork);
632         mutex_unlock(&con->sock_mutex);
633         return -EAGAIN;
634
635 out_close:
636         mutex_unlock(&con->sock_mutex);
637         if (ret != -EAGAIN) {
638                 close_connection(con, false);
639                 /* Reconnect when there is something to send */
640         }
641         /* Don't return success if we really got EOF */
642         if (ret == 0)
643                 ret = -EAGAIN;
644
645         return ret;
646 }
647
648 /* Listening socket is busy, accept a connection */
649 static int tcp_accept_from_sock(struct connection *con)
650 {
651         int result;
652         struct sockaddr_storage peeraddr;
653         struct socket *newsock;
654         int len;
655         int nodeid;
656         struct connection *newcon;
657         struct connection *addcon;
658
659         memset(&peeraddr, 0, sizeof(peeraddr));
660         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
661                                   IPPROTO_TCP, &newsock);
662         if (result < 0)
663                 return -ENOMEM;
664
665         mutex_lock_nested(&con->sock_mutex, 0);
666
667         result = -ENOTCONN;
668         if (con->sock == NULL)
669                 goto accept_err;
670
671         newsock->type = con->sock->type;
672         newsock->ops = con->sock->ops;
673
674         result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
675         if (result < 0)
676                 goto accept_err;
677
678         /* Get the connected socket's peer */
679         memset(&peeraddr, 0, sizeof(peeraddr));
680         if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
681                                   &len, 2)) {
682                 result = -ECONNABORTED;
683                 goto accept_err;
684         }
685
686         /* Get the new node's NODEID */
687         make_sockaddr(&peeraddr, 0, &len);
688         if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
689                 log_print("connect from non cluster node");
690                 sock_release(newsock);
691                 mutex_unlock(&con->sock_mutex);
692                 return -1;
693         }
694
695         log_print("got connection from %d", nodeid);
696
697         /*  Check to see if we already have a connection to this node. This
698          *  could happen if the two nodes initiate a connection at roughly
699          *  the same time and the connections cross on the wire.
700          *  In this case we store the incoming one in "othercon"
701          */
702         newcon = nodeid2con(nodeid, GFP_KERNEL);
703         if (!newcon) {
704                 result = -ENOMEM;
705                 goto accept_err;
706         }
707         mutex_lock_nested(&newcon->sock_mutex, 1);
708         if (newcon->sock) {
709                 struct connection *othercon = newcon->othercon;
710
711                 if (!othercon) {
712                         othercon = kmem_cache_zalloc(con_cache, GFP_KERNEL);
713                         if (!othercon) {
714                                 log_print("failed to allocate incoming socket");
715                                 mutex_unlock(&newcon->sock_mutex);
716                                 result = -ENOMEM;
717                                 goto accept_err;
718                         }
719                         othercon->nodeid = nodeid;
720                         othercon->rx_action = receive_from_sock;
721                         mutex_init(&othercon->sock_mutex);
722                         INIT_WORK(&othercon->swork, process_send_sockets);
723                         INIT_WORK(&othercon->rwork, process_recv_sockets);
724                         set_bit(CF_IS_OTHERCON, &othercon->flags);
725                 }
726                 if (!othercon->sock) {
727                         newcon->othercon = othercon;
728                         othercon->sock = newsock;
729                         newsock->sk->sk_user_data = othercon;
730                         add_sock(newsock, othercon);
731                         addcon = othercon;
732                 }
733                 else {
734                         printk("Extra connection from node %d attempted\n", nodeid);
735                         result = -EAGAIN;
736                         mutex_unlock(&newcon->sock_mutex);
737                         goto accept_err;
738                 }
739         }
740         else {
741                 newsock->sk->sk_user_data = newcon;
742                 newcon->rx_action = receive_from_sock;
743                 add_sock(newsock, newcon);
744                 addcon = newcon;
745         }
746
747         mutex_unlock(&newcon->sock_mutex);
748
749         /*
750          * Add it to the active queue in case we got data
751          * beween processing the accept adding the socket
752          * to the read_sockets list
753          */
754         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
755                 queue_work(recv_workqueue, &addcon->rwork);
756         mutex_unlock(&con->sock_mutex);
757
758         return 0;
759
760 accept_err:
761         mutex_unlock(&con->sock_mutex);
762         sock_release(newsock);
763
764         if (result != -EAGAIN)
765                 log_print("error accepting connection from node: %d", result);
766         return result;
767 }
768
769 static void free_entry(struct writequeue_entry *e)
770 {
771         __free_page(e->page);
772         kfree(e);
773 }
774
775 /* Initiate an SCTP association.
776    This is a special case of send_to_sock() in that we don't yet have a
777    peeled-off socket for this association, so we use the listening socket
778    and add the primary IP address of the remote node.
779  */
780 static void sctp_init_assoc(struct connection *con)
781 {
782         struct sockaddr_storage rem_addr;
783         char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
784         struct msghdr outmessage;
785         struct cmsghdr *cmsg;
786         struct sctp_sndrcvinfo *sinfo;
787         struct connection *base_con;
788         struct writequeue_entry *e;
789         int len, offset;
790         int ret;
791         int addrlen;
792         struct kvec iov[1];
793
794         if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
795                 return;
796
797         if (con->retries++ > MAX_CONNECT_RETRIES)
798                 return;
799
800         log_print("Initiating association with node %d", con->nodeid);
801
802         if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
803                 log_print("no address for nodeid %d", con->nodeid);
804                 return;
805         }
806         base_con = nodeid2con(0, 0);
807         BUG_ON(base_con == NULL);
808
809         make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
810
811         outmessage.msg_name = &rem_addr;
812         outmessage.msg_namelen = addrlen;
813         outmessage.msg_control = outcmsg;
814         outmessage.msg_controllen = sizeof(outcmsg);
815         outmessage.msg_flags = MSG_EOR;
816
817         spin_lock(&con->writequeue_lock);
818         e = list_entry(con->writequeue.next, struct writequeue_entry,
819                        list);
820
821         BUG_ON((struct list_head *) e == &con->writequeue);
822
823         len = e->len;
824         offset = e->offset;
825         spin_unlock(&con->writequeue_lock);
826         kmap(e->page);
827
828         /* Send the first block off the write queue */
829         iov[0].iov_base = page_address(e->page)+offset;
830         iov[0].iov_len = len;
831
832         cmsg = CMSG_FIRSTHDR(&outmessage);
833         cmsg->cmsg_level = IPPROTO_SCTP;
834         cmsg->cmsg_type = SCTP_SNDRCV;
835         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
836         sinfo = CMSG_DATA(cmsg);
837         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
838         sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
839         outmessage.msg_controllen = cmsg->cmsg_len;
840
841         ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
842         if (ret < 0) {
843                 log_print("Send first packet to node %d failed: %d",
844                           con->nodeid, ret);
845
846                 /* Try again later */
847                 clear_bit(CF_CONNECT_PENDING, &con->flags);
848                 clear_bit(CF_INIT_PENDING, &con->flags);
849         }
850         else {
851                 spin_lock(&con->writequeue_lock);
852                 e->offset += ret;
853                 e->len -= ret;
854
855                 if (e->len == 0 && e->users == 0) {
856                         list_del(&e->list);
857                         kunmap(e->page);
858                         free_entry(e);
859                 }
860                 spin_unlock(&con->writequeue_lock);
861         }
862 }
863
864 /* Connect a new socket to its peer */
865 static void tcp_connect_to_sock(struct connection *con)
866 {
867         int result = -EHOSTUNREACH;
868         struct sockaddr_storage saddr, src_addr;
869         int addr_len;
870         struct socket *sock;
871
872         if (con->nodeid == 0) {
873                 log_print("attempt to connect sock 0 foiled");
874                 return;
875         }
876
877         mutex_lock(&con->sock_mutex);
878         if (con->retries++ > MAX_CONNECT_RETRIES)
879                 goto out;
880
881         /* Some odd races can cause double-connects, ignore them */
882         if (con->sock) {
883                 result = 0;
884                 goto out;
885         }
886
887         /* Create a socket to communicate with */
888         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
889                                   IPPROTO_TCP, &sock);
890         if (result < 0)
891                 goto out_err;
892
893         memset(&saddr, 0, sizeof(saddr));
894         if (dlm_nodeid_to_addr(con->nodeid, &saddr)) {
895                 sock_release(sock);
896                 goto out_err;
897         }
898
899         sock->sk->sk_user_data = con;
900         con->rx_action = receive_from_sock;
901         con->connect_action = tcp_connect_to_sock;
902         add_sock(sock, con);
903
904         /* Bind to our cluster-known address connecting to avoid
905            routing problems */
906         memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
907         make_sockaddr(&src_addr, 0, &addr_len);
908         result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
909                                  addr_len);
910         if (result < 0) {
911                 log_print("could not bind for connect: %d", result);
912                 /* This *may* not indicate a critical error */
913         }
914
915         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
916
917         log_print("connecting to %d", con->nodeid);
918         result =
919                 sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
920                                    O_NONBLOCK);
921         if (result == -EINPROGRESS)
922                 result = 0;
923         if (result == 0)
924                 goto out;
925
926 out_err:
927         if (con->sock) {
928                 sock_release(con->sock);
929                 con->sock = NULL;
930         }
931         /*
932          * Some errors are fatal and this list might need adjusting. For other
933          * errors we try again until the max number of retries is reached.
934          */
935         if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
936             result != -ENETDOWN && result != -EINVAL
937             && result != -EPROTONOSUPPORT) {
938                 lowcomms_connect_sock(con);
939                 result = 0;
940         }
941 out:
942         mutex_unlock(&con->sock_mutex);
943         return;
944 }
945
946 static struct socket *tcp_create_listen_sock(struct connection *con,
947                                              struct sockaddr_storage *saddr)
948 {
949         struct socket *sock = NULL;
950         int result = 0;
951         int one = 1;
952         int addr_len;
953
954         if (dlm_local_addr[0]->ss_family == AF_INET)
955                 addr_len = sizeof(struct sockaddr_in);
956         else
957                 addr_len = sizeof(struct sockaddr_in6);
958
959         /* Create a socket to communicate with */
960         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
961                                   IPPROTO_TCP, &sock);
962         if (result < 0) {
963                 log_print("Can't create listening comms socket");
964                 goto create_out;
965         }
966
967         result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
968                                    (char *)&one, sizeof(one));
969
970         if (result < 0) {
971                 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
972         }
973         sock->sk->sk_user_data = con;
974         con->rx_action = tcp_accept_from_sock;
975         con->connect_action = tcp_connect_to_sock;
976         con->sock = sock;
977
978         /* Bind to our port */
979         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
980         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
981         if (result < 0) {
982                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
983                 sock_release(sock);
984                 sock = NULL;
985                 con->sock = NULL;
986                 goto create_out;
987         }
988         result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
989                                  (char *)&one, sizeof(one));
990         if (result < 0) {
991                 log_print("Set keepalive failed: %d", result);
992         }
993
994         result = sock->ops->listen(sock, 5);
995         if (result < 0) {
996                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
997                 sock_release(sock);
998                 sock = NULL;
999                 goto create_out;
1000         }
1001
1002 create_out:
1003         return sock;
1004 }
1005
1006 /* Get local addresses */
1007 static void init_local(void)
1008 {
1009         struct sockaddr_storage sas, *addr;
1010         int i;
1011
1012         dlm_local_count = 0;
1013         for (i = 0; i < DLM_MAX_ADDR_COUNT - 1; i++) {
1014                 if (dlm_our_addr(&sas, i))
1015                         break;
1016
1017                 addr = kmalloc(sizeof(*addr), GFP_KERNEL);
1018                 if (!addr)
1019                         break;
1020                 memcpy(addr, &sas, sizeof(*addr));
1021                 dlm_local_addr[dlm_local_count++] = addr;
1022         }
1023 }
1024
1025 /* Bind to an IP address. SCTP allows multiple address so it can do
1026    multi-homing */
1027 static int add_sctp_bind_addr(struct connection *sctp_con,
1028                               struct sockaddr_storage *addr,
1029                               int addr_len, int num)
1030 {
1031         int result = 0;
1032
1033         if (num == 1)
1034                 result = kernel_bind(sctp_con->sock,
1035                                      (struct sockaddr *) addr,
1036                                      addr_len);
1037         else
1038                 result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
1039                                            SCTP_SOCKOPT_BINDX_ADD,
1040                                            (char *)addr, addr_len);
1041
1042         if (result < 0)
1043                 log_print("Can't bind to port %d addr number %d",
1044                           dlm_config.ci_tcp_port, num);
1045
1046         return result;
1047 }
1048
1049 /* Initialise SCTP socket and bind to all interfaces */
1050 static int sctp_listen_for_all(void)
1051 {
1052         struct socket *sock = NULL;
1053         struct sockaddr_storage localaddr;
1054         struct sctp_event_subscribe subscribe;
1055         int result = -EINVAL, num = 1, i, addr_len;
1056         struct connection *con = nodeid2con(0, GFP_KERNEL);
1057         int bufsize = NEEDED_RMEM;
1058
1059         if (!con)
1060                 return -ENOMEM;
1061
1062         log_print("Using SCTP for communications");
1063
1064         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
1065                                   IPPROTO_SCTP, &sock);
1066         if (result < 0) {
1067                 log_print("Can't create comms socket, check SCTP is loaded");
1068                 goto out;
1069         }
1070
1071         /* Listen for events */
1072         memset(&subscribe, 0, sizeof(subscribe));
1073         subscribe.sctp_data_io_event = 1;
1074         subscribe.sctp_association_event = 1;
1075         subscribe.sctp_send_failure_event = 1;
1076         subscribe.sctp_shutdown_event = 1;
1077         subscribe.sctp_partial_delivery_event = 1;
1078
1079         result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1080                                  (char *)&bufsize, sizeof(bufsize));
1081         if (result)
1082                 log_print("Error increasing buffer space on socket %d", result);
1083
1084         result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
1085                                    (char *)&subscribe, sizeof(subscribe));
1086         if (result < 0) {
1087                 log_print("Failed to set SCTP_EVENTS on socket: result=%d",
1088                           result);
1089                 goto create_delsock;
1090         }
1091
1092         /* Init con struct */
1093         sock->sk->sk_user_data = con;
1094         con->sock = sock;
1095         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1096         con->rx_action = receive_from_sock;
1097         con->connect_action = sctp_init_assoc;
1098
1099         /* Bind to all interfaces. */
1100         for (i = 0; i < dlm_local_count; i++) {
1101                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1102                 make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
1103
1104                 result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
1105                 if (result)
1106                         goto create_delsock;
1107                 ++num;
1108         }
1109
1110         result = sock->ops->listen(sock, 5);
1111         if (result < 0) {
1112                 log_print("Can't set socket listening");
1113                 goto create_delsock;
1114         }
1115
1116         return 0;
1117
1118 create_delsock:
1119         sock_release(sock);
1120         con->sock = NULL;
1121 out:
1122         return result;
1123 }
1124
1125 static int tcp_listen_for_all(void)
1126 {
1127         struct socket *sock = NULL;
1128         struct connection *con = nodeid2con(0, GFP_KERNEL);
1129         int result = -EINVAL;
1130
1131         if (!con)
1132                 return -ENOMEM;
1133
1134         /* We don't support multi-homed hosts */
1135         if (dlm_local_addr[1] != NULL) {
1136                 log_print("TCP protocol can't handle multi-homed hosts, "
1137                           "try SCTP");
1138                 return -EINVAL;
1139         }
1140
1141         log_print("Using TCP for communications");
1142
1143         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1144         if (sock) {
1145                 add_sock(sock, con);
1146                 result = 0;
1147         }
1148         else {
1149                 result = -EADDRINUSE;
1150         }
1151
1152         return result;
1153 }
1154
1155
1156
1157 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1158                                                      gfp_t allocation)
1159 {
1160         struct writequeue_entry *entry;
1161
1162         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1163         if (!entry)
1164                 return NULL;
1165
1166         entry->page = alloc_page(allocation);
1167         if (!entry->page) {
1168                 kfree(entry);
1169                 return NULL;
1170         }
1171
1172         entry->offset = 0;
1173         entry->len = 0;
1174         entry->end = 0;
1175         entry->users = 0;
1176         entry->con = con;
1177
1178         return entry;
1179 }
1180
1181 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1182 {
1183         struct connection *con;
1184         struct writequeue_entry *e;
1185         int offset = 0;
1186         int users = 0;
1187
1188         con = nodeid2con(nodeid, allocation);
1189         if (!con)
1190                 return NULL;
1191
1192         spin_lock(&con->writequeue_lock);
1193         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1194         if ((&e->list == &con->writequeue) ||
1195             (PAGE_CACHE_SIZE - e->end < len)) {
1196                 e = NULL;
1197         } else {
1198                 offset = e->end;
1199                 e->end += len;
1200                 users = e->users++;
1201         }
1202         spin_unlock(&con->writequeue_lock);
1203
1204         if (e) {
1205         got_one:
1206                 if (users == 0)
1207                         kmap(e->page);
1208                 *ppc = page_address(e->page) + offset;
1209                 return e;
1210         }
1211
1212         e = new_writequeue_entry(con, allocation);
1213         if (e) {
1214                 spin_lock(&con->writequeue_lock);
1215                 offset = e->end;
1216                 e->end += len;
1217                 users = e->users++;
1218                 list_add_tail(&e->list, &con->writequeue);
1219                 spin_unlock(&con->writequeue_lock);
1220                 goto got_one;
1221         }
1222         return NULL;
1223 }
1224
1225 void dlm_lowcomms_commit_buffer(void *mh)
1226 {
1227         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1228         struct connection *con = e->con;
1229         int users;
1230
1231         spin_lock(&con->writequeue_lock);
1232         users = --e->users;
1233         if (users)
1234                 goto out;
1235         e->len = e->end - e->offset;
1236         kunmap(e->page);
1237         spin_unlock(&con->writequeue_lock);
1238
1239         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1240                 queue_work(send_workqueue, &con->swork);
1241         }
1242         return;
1243
1244 out:
1245         spin_unlock(&con->writequeue_lock);
1246         return;
1247 }
1248
1249 /* Send a message */
1250 static void send_to_sock(struct connection *con)
1251 {
1252         int ret = 0;
1253         ssize_t(*sendpage) (struct socket *, struct page *, int, size_t, int);
1254         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1255         struct writequeue_entry *e;
1256         int len, offset;
1257
1258         mutex_lock(&con->sock_mutex);
1259         if (con->sock == NULL)
1260                 goto out_connect;
1261
1262         sendpage = con->sock->ops->sendpage;
1263
1264         spin_lock(&con->writequeue_lock);
1265         for (;;) {
1266                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1267                                list);
1268                 if ((struct list_head *) e == &con->writequeue)
1269                         break;
1270
1271                 len = e->len;
1272                 offset = e->offset;
1273                 BUG_ON(len == 0 && e->users == 0);
1274                 spin_unlock(&con->writequeue_lock);
1275                 kmap(e->page);
1276
1277                 ret = 0;
1278                 if (len) {
1279                         ret = sendpage(con->sock, e->page, offset, len,
1280                                        msg_flags);
1281                         if (ret == -EAGAIN || ret == 0) {
1282                                 cond_resched();
1283                                 goto out;
1284                         }
1285                         if (ret <= 0)
1286                                 goto send_error;
1287                 }
1288                         /* Don't starve people filling buffers */
1289                         cond_resched();
1290
1291                 spin_lock(&con->writequeue_lock);
1292                 e->offset += ret;
1293                 e->len -= ret;
1294
1295                 if (e->len == 0 && e->users == 0) {
1296                         list_del(&e->list);
1297                         kunmap(e->page);
1298                         free_entry(e);
1299                         continue;
1300                 }
1301         }
1302         spin_unlock(&con->writequeue_lock);
1303 out:
1304         mutex_unlock(&con->sock_mutex);
1305         return;
1306
1307 send_error:
1308         mutex_unlock(&con->sock_mutex);
1309         close_connection(con, false);
1310         lowcomms_connect_sock(con);
1311         return;
1312
1313 out_connect:
1314         mutex_unlock(&con->sock_mutex);
1315         if (!test_bit(CF_INIT_PENDING, &con->flags))
1316                 lowcomms_connect_sock(con);
1317         return;
1318 }
1319
1320 static void clean_one_writequeue(struct connection *con)
1321 {
1322         struct list_head *list;
1323         struct list_head *temp;
1324
1325         spin_lock(&con->writequeue_lock);
1326         list_for_each_safe(list, temp, &con->writequeue) {
1327                 struct writequeue_entry *e =
1328                         list_entry(list, struct writequeue_entry, list);
1329                 list_del(&e->list);
1330                 free_entry(e);
1331         }
1332         spin_unlock(&con->writequeue_lock);
1333 }
1334
1335 /* Called from recovery when it knows that a node has
1336    left the cluster */
1337 int dlm_lowcomms_close(int nodeid)
1338 {
1339         struct connection *con;
1340
1341         log_print("closing connection to node %d", nodeid);
1342         con = nodeid2con(nodeid, 0);
1343         if (con) {
1344                 clean_one_writequeue(con);
1345                 close_connection(con, true);
1346         }
1347         return 0;
1348 }
1349
1350 /* Receive workqueue function */
1351 static void process_recv_sockets(struct work_struct *work)
1352 {
1353         struct connection *con = container_of(work, struct connection, rwork);
1354         int err;
1355
1356         clear_bit(CF_READ_PENDING, &con->flags);
1357         do {
1358                 err = con->rx_action(con);
1359         } while (!err);
1360 }
1361
1362 /* Send workqueue function */
1363 static void process_send_sockets(struct work_struct *work)
1364 {
1365         struct connection *con = container_of(work, struct connection, swork);
1366
1367         if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1368                 con->connect_action(con);
1369         }
1370         clear_bit(CF_WRITE_PENDING, &con->flags);
1371         send_to_sock(con);
1372 }
1373
1374
1375 /* Discard all entries on the write queues */
1376 static void clean_writequeues(void)
1377 {
1378         int nodeid;
1379
1380         for (nodeid = 1; nodeid <= max_nodeid; nodeid++) {
1381                 struct connection *con = __nodeid2con(nodeid, 0);
1382
1383                 if (con)
1384                         clean_one_writequeue(con);
1385         }
1386 }
1387
1388 static void work_stop(void)
1389 {
1390         destroy_workqueue(recv_workqueue);
1391         destroy_workqueue(send_workqueue);
1392 }
1393
1394 static int work_start(void)
1395 {
1396         int error;
1397         recv_workqueue = create_workqueue("dlm_recv");
1398         error = IS_ERR(recv_workqueue);
1399         if (error) {
1400                 log_print("can't start dlm_recv %d", error);
1401                 return error;
1402         }
1403
1404         send_workqueue = create_singlethread_workqueue("dlm_send");
1405         error = IS_ERR(send_workqueue);
1406         if (error) {
1407                 log_print("can't start dlm_send %d", error);
1408                 destroy_workqueue(recv_workqueue);
1409                 return error;
1410         }
1411
1412         return 0;
1413 }
1414
1415 void dlm_lowcomms_stop(void)
1416 {
1417         int i;
1418         struct connection *con;
1419
1420         /* Set all the flags to prevent any
1421            socket activity.
1422         */
1423         mutex_lock(&connections_lock);
1424         for (i = 0; i <= max_nodeid; i++) {
1425                 con = __nodeid2con(i, 0);
1426                 if (con) {
1427                         con->flags |= 0x0F;
1428                         if (con->sock)
1429                                 con->sock->sk->sk_user_data = NULL;
1430                 }
1431         }
1432         mutex_unlock(&connections_lock);
1433
1434         work_stop();
1435
1436         mutex_lock(&connections_lock);
1437         clean_writequeues();
1438
1439         for (i = 0; i <= max_nodeid; i++) {
1440                 con = __nodeid2con(i, 0);
1441                 if (con) {
1442                         close_connection(con, true);
1443                         if (con->othercon)
1444                                 kmem_cache_free(con_cache, con->othercon);
1445                         kmem_cache_free(con_cache, con);
1446                 }
1447         }
1448         max_nodeid = 0;
1449         mutex_unlock(&connections_lock);
1450         kmem_cache_destroy(con_cache);
1451         idr_init(&connections_idr);
1452 }
1453
1454 int dlm_lowcomms_start(void)
1455 {
1456         int error = -EINVAL;
1457         struct connection *con;
1458
1459         init_local();
1460         if (!dlm_local_count) {
1461                 error = -ENOTCONN;
1462                 log_print("no local IP address has been set");
1463                 goto out;
1464         }
1465
1466         error = -ENOMEM;
1467         con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1468                                       __alignof__(struct connection), 0,
1469                                       NULL);
1470         if (!con_cache)
1471                 goto out;
1472
1473         /* Start listening */
1474         if (dlm_config.ci_protocol == 0)
1475                 error = tcp_listen_for_all();
1476         else
1477                 error = sctp_listen_for_all();
1478         if (error)
1479                 goto fail_unlisten;
1480
1481         error = work_start();
1482         if (error)
1483                 goto fail_unlisten;
1484
1485         return 0;
1486
1487 fail_unlisten:
1488         con = nodeid2con(0,0);
1489         if (con) {
1490                 close_connection(con, false);
1491                 kmem_cache_free(con_cache, con);
1492         }
1493         kmem_cache_destroy(con_cache);
1494
1495 out:
1496         return error;
1497 }