Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
[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                 goto out_err;
896
897         sock->sk->sk_user_data = con;
898         con->rx_action = receive_from_sock;
899         con->connect_action = tcp_connect_to_sock;
900         add_sock(sock, con);
901
902         /* Bind to our cluster-known address connecting to avoid
903            routing problems */
904         memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
905         make_sockaddr(&src_addr, 0, &addr_len);
906         result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
907                                  addr_len);
908         if (result < 0) {
909                 log_print("could not bind for connect: %d", result);
910                 /* This *may* not indicate a critical error */
911         }
912
913         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
914
915         log_print("connecting to %d", con->nodeid);
916         result =
917                 sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
918                                    O_NONBLOCK);
919         if (result == -EINPROGRESS)
920                 result = 0;
921         if (result == 0)
922                 goto out;
923
924 out_err:
925         if (con->sock) {
926                 sock_release(con->sock);
927                 con->sock = NULL;
928         }
929         /*
930          * Some errors are fatal and this list might need adjusting. For other
931          * errors we try again until the max number of retries is reached.
932          */
933         if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
934             result != -ENETDOWN && result != -EINVAL
935             && result != -EPROTONOSUPPORT) {
936                 lowcomms_connect_sock(con);
937                 result = 0;
938         }
939 out:
940         mutex_unlock(&con->sock_mutex);
941         return;
942 }
943
944 static struct socket *tcp_create_listen_sock(struct connection *con,
945                                              struct sockaddr_storage *saddr)
946 {
947         struct socket *sock = NULL;
948         int result = 0;
949         int one = 1;
950         int addr_len;
951
952         if (dlm_local_addr[0]->ss_family == AF_INET)
953                 addr_len = sizeof(struct sockaddr_in);
954         else
955                 addr_len = sizeof(struct sockaddr_in6);
956
957         /* Create a socket to communicate with */
958         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
959                                   IPPROTO_TCP, &sock);
960         if (result < 0) {
961                 log_print("Can't create listening comms socket");
962                 goto create_out;
963         }
964
965         result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
966                                    (char *)&one, sizeof(one));
967
968         if (result < 0) {
969                 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
970         }
971         sock->sk->sk_user_data = con;
972         con->rx_action = tcp_accept_from_sock;
973         con->connect_action = tcp_connect_to_sock;
974         con->sock = sock;
975
976         /* Bind to our port */
977         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
978         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
979         if (result < 0) {
980                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
981                 sock_release(sock);
982                 sock = NULL;
983                 con->sock = NULL;
984                 goto create_out;
985         }
986         result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
987                                  (char *)&one, sizeof(one));
988         if (result < 0) {
989                 log_print("Set keepalive failed: %d", result);
990         }
991
992         result = sock->ops->listen(sock, 5);
993         if (result < 0) {
994                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
995                 sock_release(sock);
996                 sock = NULL;
997                 goto create_out;
998         }
999
1000 create_out:
1001         return sock;
1002 }
1003
1004 /* Get local addresses */
1005 static void init_local(void)
1006 {
1007         struct sockaddr_storage sas, *addr;
1008         int i;
1009
1010         dlm_local_count = 0;
1011         for (i = 0; i < DLM_MAX_ADDR_COUNT - 1; i++) {
1012                 if (dlm_our_addr(&sas, i))
1013                         break;
1014
1015                 addr = kmalloc(sizeof(*addr), GFP_KERNEL);
1016                 if (!addr)
1017                         break;
1018                 memcpy(addr, &sas, sizeof(*addr));
1019                 dlm_local_addr[dlm_local_count++] = addr;
1020         }
1021 }
1022
1023 /* Bind to an IP address. SCTP allows multiple address so it can do
1024    multi-homing */
1025 static int add_sctp_bind_addr(struct connection *sctp_con,
1026                               struct sockaddr_storage *addr,
1027                               int addr_len, int num)
1028 {
1029         int result = 0;
1030
1031         if (num == 1)
1032                 result = kernel_bind(sctp_con->sock,
1033                                      (struct sockaddr *) addr,
1034                                      addr_len);
1035         else
1036                 result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
1037                                            SCTP_SOCKOPT_BINDX_ADD,
1038                                            (char *)addr, addr_len);
1039
1040         if (result < 0)
1041                 log_print("Can't bind to port %d addr number %d",
1042                           dlm_config.ci_tcp_port, num);
1043
1044         return result;
1045 }
1046
1047 /* Initialise SCTP socket and bind to all interfaces */
1048 static int sctp_listen_for_all(void)
1049 {
1050         struct socket *sock = NULL;
1051         struct sockaddr_storage localaddr;
1052         struct sctp_event_subscribe subscribe;
1053         int result = -EINVAL, num = 1, i, addr_len;
1054         struct connection *con = nodeid2con(0, GFP_KERNEL);
1055         int bufsize = NEEDED_RMEM;
1056
1057         if (!con)
1058                 return -ENOMEM;
1059
1060         log_print("Using SCTP for communications");
1061
1062         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
1063                                   IPPROTO_SCTP, &sock);
1064         if (result < 0) {
1065                 log_print("Can't create comms socket, check SCTP is loaded");
1066                 goto out;
1067         }
1068
1069         /* Listen for events */
1070         memset(&subscribe, 0, sizeof(subscribe));
1071         subscribe.sctp_data_io_event = 1;
1072         subscribe.sctp_association_event = 1;
1073         subscribe.sctp_send_failure_event = 1;
1074         subscribe.sctp_shutdown_event = 1;
1075         subscribe.sctp_partial_delivery_event = 1;
1076
1077         result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1078                                  (char *)&bufsize, sizeof(bufsize));
1079         if (result)
1080                 log_print("Error increasing buffer space on socket %d", result);
1081
1082         result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
1083                                    (char *)&subscribe, sizeof(subscribe));
1084         if (result < 0) {
1085                 log_print("Failed to set SCTP_EVENTS on socket: result=%d",
1086                           result);
1087                 goto create_delsock;
1088         }
1089
1090         /* Init con struct */
1091         sock->sk->sk_user_data = con;
1092         con->sock = sock;
1093         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1094         con->rx_action = receive_from_sock;
1095         con->connect_action = sctp_init_assoc;
1096
1097         /* Bind to all interfaces. */
1098         for (i = 0; i < dlm_local_count; i++) {
1099                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1100                 make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
1101
1102                 result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
1103                 if (result)
1104                         goto create_delsock;
1105                 ++num;
1106         }
1107
1108         result = sock->ops->listen(sock, 5);
1109         if (result < 0) {
1110                 log_print("Can't set socket listening");
1111                 goto create_delsock;
1112         }
1113
1114         return 0;
1115
1116 create_delsock:
1117         sock_release(sock);
1118         con->sock = NULL;
1119 out:
1120         return result;
1121 }
1122
1123 static int tcp_listen_for_all(void)
1124 {
1125         struct socket *sock = NULL;
1126         struct connection *con = nodeid2con(0, GFP_KERNEL);
1127         int result = -EINVAL;
1128
1129         if (!con)
1130                 return -ENOMEM;
1131
1132         /* We don't support multi-homed hosts */
1133         if (dlm_local_addr[1] != NULL) {
1134                 log_print("TCP protocol can't handle multi-homed hosts, "
1135                           "try SCTP");
1136                 return -EINVAL;
1137         }
1138
1139         log_print("Using TCP for communications");
1140
1141         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1142         if (sock) {
1143                 add_sock(sock, con);
1144                 result = 0;
1145         }
1146         else {
1147                 result = -EADDRINUSE;
1148         }
1149
1150         return result;
1151 }
1152
1153
1154
1155 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1156                                                      gfp_t allocation)
1157 {
1158         struct writequeue_entry *entry;
1159
1160         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1161         if (!entry)
1162                 return NULL;
1163
1164         entry->page = alloc_page(allocation);
1165         if (!entry->page) {
1166                 kfree(entry);
1167                 return NULL;
1168         }
1169
1170         entry->offset = 0;
1171         entry->len = 0;
1172         entry->end = 0;
1173         entry->users = 0;
1174         entry->con = con;
1175
1176         return entry;
1177 }
1178
1179 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1180 {
1181         struct connection *con;
1182         struct writequeue_entry *e;
1183         int offset = 0;
1184         int users = 0;
1185
1186         con = nodeid2con(nodeid, allocation);
1187         if (!con)
1188                 return NULL;
1189
1190         spin_lock(&con->writequeue_lock);
1191         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1192         if ((&e->list == &con->writequeue) ||
1193             (PAGE_CACHE_SIZE - e->end < len)) {
1194                 e = NULL;
1195         } else {
1196                 offset = e->end;
1197                 e->end += len;
1198                 users = e->users++;
1199         }
1200         spin_unlock(&con->writequeue_lock);
1201
1202         if (e) {
1203         got_one:
1204                 if (users == 0)
1205                         kmap(e->page);
1206                 *ppc = page_address(e->page) + offset;
1207                 return e;
1208         }
1209
1210         e = new_writequeue_entry(con, allocation);
1211         if (e) {
1212                 spin_lock(&con->writequeue_lock);
1213                 offset = e->end;
1214                 e->end += len;
1215                 users = e->users++;
1216                 list_add_tail(&e->list, &con->writequeue);
1217                 spin_unlock(&con->writequeue_lock);
1218                 goto got_one;
1219         }
1220         return NULL;
1221 }
1222
1223 void dlm_lowcomms_commit_buffer(void *mh)
1224 {
1225         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1226         struct connection *con = e->con;
1227         int users;
1228
1229         spin_lock(&con->writequeue_lock);
1230         users = --e->users;
1231         if (users)
1232                 goto out;
1233         e->len = e->end - e->offset;
1234         kunmap(e->page);
1235         spin_unlock(&con->writequeue_lock);
1236
1237         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1238                 queue_work(send_workqueue, &con->swork);
1239         }
1240         return;
1241
1242 out:
1243         spin_unlock(&con->writequeue_lock);
1244         return;
1245 }
1246
1247 /* Send a message */
1248 static void send_to_sock(struct connection *con)
1249 {
1250         int ret = 0;
1251         ssize_t(*sendpage) (struct socket *, struct page *, int, size_t, int);
1252         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1253         struct writequeue_entry *e;
1254         int len, offset;
1255
1256         mutex_lock(&con->sock_mutex);
1257         if (con->sock == NULL)
1258                 goto out_connect;
1259
1260         sendpage = con->sock->ops->sendpage;
1261
1262         spin_lock(&con->writequeue_lock);
1263         for (;;) {
1264                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1265                                list);
1266                 if ((struct list_head *) e == &con->writequeue)
1267                         break;
1268
1269                 len = e->len;
1270                 offset = e->offset;
1271                 BUG_ON(len == 0 && e->users == 0);
1272                 spin_unlock(&con->writequeue_lock);
1273                 kmap(e->page);
1274
1275                 ret = 0;
1276                 if (len) {
1277                         ret = sendpage(con->sock, e->page, offset, len,
1278                                        msg_flags);
1279                         if (ret == -EAGAIN || ret == 0) {
1280                                 cond_resched();
1281                                 goto out;
1282                         }
1283                         if (ret <= 0)
1284                                 goto send_error;
1285                 }
1286                         /* Don't starve people filling buffers */
1287                         cond_resched();
1288
1289                 spin_lock(&con->writequeue_lock);
1290                 e->offset += ret;
1291                 e->len -= ret;
1292
1293                 if (e->len == 0 && e->users == 0) {
1294                         list_del(&e->list);
1295                         kunmap(e->page);
1296                         free_entry(e);
1297                         continue;
1298                 }
1299         }
1300         spin_unlock(&con->writequeue_lock);
1301 out:
1302         mutex_unlock(&con->sock_mutex);
1303         return;
1304
1305 send_error:
1306         mutex_unlock(&con->sock_mutex);
1307         close_connection(con, false);
1308         lowcomms_connect_sock(con);
1309         return;
1310
1311 out_connect:
1312         mutex_unlock(&con->sock_mutex);
1313         if (!test_bit(CF_INIT_PENDING, &con->flags))
1314                 lowcomms_connect_sock(con);
1315         return;
1316 }
1317
1318 static void clean_one_writequeue(struct connection *con)
1319 {
1320         struct list_head *list;
1321         struct list_head *temp;
1322
1323         spin_lock(&con->writequeue_lock);
1324         list_for_each_safe(list, temp, &con->writequeue) {
1325                 struct writequeue_entry *e =
1326                         list_entry(list, struct writequeue_entry, list);
1327                 list_del(&e->list);
1328                 free_entry(e);
1329         }
1330         spin_unlock(&con->writequeue_lock);
1331 }
1332
1333 /* Called from recovery when it knows that a node has
1334    left the cluster */
1335 int dlm_lowcomms_close(int nodeid)
1336 {
1337         struct connection *con;
1338
1339         log_print("closing connection to node %d", nodeid);
1340         con = nodeid2con(nodeid, 0);
1341         if (con) {
1342                 clean_one_writequeue(con);
1343                 close_connection(con, true);
1344         }
1345         return 0;
1346 }
1347
1348 /* Receive workqueue function */
1349 static void process_recv_sockets(struct work_struct *work)
1350 {
1351         struct connection *con = container_of(work, struct connection, rwork);
1352         int err;
1353
1354         clear_bit(CF_READ_PENDING, &con->flags);
1355         do {
1356                 err = con->rx_action(con);
1357         } while (!err);
1358 }
1359
1360 /* Send workqueue function */
1361 static void process_send_sockets(struct work_struct *work)
1362 {
1363         struct connection *con = container_of(work, struct connection, swork);
1364
1365         if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1366                 con->connect_action(con);
1367         }
1368         clear_bit(CF_WRITE_PENDING, &con->flags);
1369         send_to_sock(con);
1370 }
1371
1372
1373 /* Discard all entries on the write queues */
1374 static void clean_writequeues(void)
1375 {
1376         int nodeid;
1377
1378         for (nodeid = 1; nodeid <= max_nodeid; nodeid++) {
1379                 struct connection *con = __nodeid2con(nodeid, 0);
1380
1381                 if (con)
1382                         clean_one_writequeue(con);
1383         }
1384 }
1385
1386 static void work_stop(void)
1387 {
1388         destroy_workqueue(recv_workqueue);
1389         destroy_workqueue(send_workqueue);
1390 }
1391
1392 static int work_start(void)
1393 {
1394         int error;
1395         recv_workqueue = create_workqueue("dlm_recv");
1396         error = IS_ERR(recv_workqueue);
1397         if (error) {
1398                 log_print("can't start dlm_recv %d", error);
1399                 return error;
1400         }
1401
1402         send_workqueue = create_singlethread_workqueue("dlm_send");
1403         error = IS_ERR(send_workqueue);
1404         if (error) {
1405                 log_print("can't start dlm_send %d", error);
1406                 destroy_workqueue(recv_workqueue);
1407                 return error;
1408         }
1409
1410         return 0;
1411 }
1412
1413 void dlm_lowcomms_stop(void)
1414 {
1415         int i;
1416         struct connection *con;
1417
1418         /* Set all the flags to prevent any
1419            socket activity.
1420         */
1421         mutex_lock(&connections_lock);
1422         for (i = 0; i <= max_nodeid; i++) {
1423                 con = __nodeid2con(i, 0);
1424                 if (con) {
1425                         con->flags |= 0x0F;
1426                         if (con->sock)
1427                                 con->sock->sk->sk_user_data = NULL;
1428                 }
1429         }
1430         mutex_unlock(&connections_lock);
1431
1432         work_stop();
1433
1434         mutex_lock(&connections_lock);
1435         clean_writequeues();
1436
1437         for (i = 0; i <= max_nodeid; i++) {
1438                 con = __nodeid2con(i, 0);
1439                 if (con) {
1440                         close_connection(con, true);
1441                         if (con->othercon)
1442                                 kmem_cache_free(con_cache, con->othercon);
1443                         kmem_cache_free(con_cache, con);
1444                 }
1445         }
1446         max_nodeid = 0;
1447         mutex_unlock(&connections_lock);
1448         kmem_cache_destroy(con_cache);
1449         idr_init(&connections_idr);
1450 }
1451
1452 int dlm_lowcomms_start(void)
1453 {
1454         int error = -EINVAL;
1455         struct connection *con;
1456
1457         init_local();
1458         if (!dlm_local_count) {
1459                 error = -ENOTCONN;
1460                 log_print("no local IP address has been set");
1461                 goto out;
1462         }
1463
1464         error = -ENOMEM;
1465         con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1466                                       __alignof__(struct connection), 0,
1467                                       NULL);
1468         if (!con_cache)
1469                 goto out;
1470
1471         /* Start listening */
1472         if (dlm_config.ci_protocol == 0)
1473                 error = tcp_listen_for_all();
1474         else
1475                 error = sctp_listen_for_all();
1476         if (error)
1477                 goto fail_unlisten;
1478
1479         error = work_start();
1480         if (error)
1481                 goto fail_unlisten;
1482
1483         return 0;
1484
1485 fail_unlisten:
1486         con = nodeid2con(0,0);
1487         if (con) {
1488                 close_connection(con, false);
1489                 kmem_cache_free(con_cache, con);
1490         }
1491         kmem_cache_destroy(con_cache);
1492
1493 out:
1494         return error;
1495 }