Merge branch 'agp-patches' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied...
[linux-2.6] / fs / dlm / lowcomms.c
1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5 **  Copyright (C) 2004-2007 Red Hat, Inc.  All rights reserved.
6 **
7 **  This copyrighted material is made available to anyone wishing to use,
8 **  modify, copy, or redistribute it subject to the terms and conditions
9 **  of the GNU General Public License v.2.
10 **
11 *******************************************************************************
12 ******************************************************************************/
13
14 /*
15  * lowcomms.c
16  *
17  * This is the "low-level" comms layer.
18  *
19  * It is responsible for sending/receiving messages
20  * from other nodes in the cluster.
21  *
22  * Cluster nodes are referred to by their nodeids. nodeids are
23  * simply 32 bit numbers to the locking module - if they need to
24  * be expanded for the cluster infrastructure then that is it's
25  * responsibility. It is this layer's
26  * responsibility to resolve these into IP address or
27  * whatever it needs for inter-node communication.
28  *
29  * The comms level is two kernel threads that deal mainly with
30  * the receiving of messages from other nodes and passing them
31  * up to the mid-level comms layer (which understands the
32  * message format) for execution by the locking core, and
33  * a send thread which does all the setting up of connections
34  * to remote nodes and the sending of data. Threads are not allowed
35  * to send their own data because it may cause them to wait in times
36  * of high load. Also, this way, the sending thread can collect together
37  * messages bound for one node and send them in one block.
38  *
39  * lowcomms will choose to use wither TCP or SCTP as its transport layer
40  * depending on the configuration variable 'protocol'. This should be set
41  * to 0 (default) for TCP or 1 for SCTP. It shouldbe configured using a
42  * cluster-wide mechanism as it must be the same on all nodes of the cluster
43  * for the DLM to function.
44  *
45  */
46
47 #include <asm/ioctls.h>
48 #include <net/sock.h>
49 #include <net/tcp.h>
50 #include <linux/pagemap.h>
51 #include <linux/idr.h>
52 #include <linux/file.h>
53 #include <linux/sctp.h>
54 #include <net/sctp/user.h>
55
56 #include "dlm_internal.h"
57 #include "lowcomms.h"
58 #include "midcomms.h"
59 #include "config.h"
60
61 #define NEEDED_RMEM (4*1024*1024)
62
63 struct cbuf {
64         unsigned int base;
65         unsigned int len;
66         unsigned int mask;
67 };
68
69 static void cbuf_add(struct cbuf *cb, int n)
70 {
71         cb->len += n;
72 }
73
74 static int cbuf_data(struct cbuf *cb)
75 {
76         return ((cb->base + cb->len) & cb->mask);
77 }
78
79 static void cbuf_init(struct cbuf *cb, int size)
80 {
81         cb->base = cb->len = 0;
82         cb->mask = size-1;
83 }
84
85 static void cbuf_eat(struct cbuf *cb, int n)
86 {
87         cb->len  -= n;
88         cb->base += n;
89         cb->base &= cb->mask;
90 }
91
92 static bool cbuf_empty(struct cbuf *cb)
93 {
94         return cb->len == 0;
95 }
96
97 struct connection {
98         struct socket *sock;    /* NULL if not connected */
99         uint32_t nodeid;        /* So we know who we are in the list */
100         struct mutex sock_mutex;
101         unsigned long flags;
102 #define CF_READ_PENDING 1
103 #define CF_WRITE_PENDING 2
104 #define CF_CONNECT_PENDING 3
105 #define CF_INIT_PENDING 4
106 #define CF_IS_OTHERCON 5
107         struct list_head writequeue;  /* List of outgoing writequeue_entries */
108         spinlock_t writequeue_lock;
109         int (*rx_action) (struct connection *); /* What to do when active */
110         void (*connect_action) (struct connection *);   /* What to do to connect */
111         struct page *rx_page;
112         struct cbuf cb;
113         int retries;
114 #define MAX_CONNECT_RETRIES 3
115         int sctp_assoc;
116         struct connection *othercon;
117         struct work_struct rwork; /* Receive workqueue */
118         struct work_struct swork; /* Send workqueue */
119 };
120 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
121
122 /* An entry waiting to be sent */
123 struct writequeue_entry {
124         struct list_head list;
125         struct page *page;
126         int offset;
127         int len;
128         int end;
129         int users;
130         struct connection *con;
131 };
132
133 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
134 static int dlm_local_count;
135
136 /* Work queues */
137 static struct workqueue_struct *recv_workqueue;
138 static struct workqueue_struct *send_workqueue;
139
140 static DEFINE_IDR(connections_idr);
141 static DECLARE_MUTEX(connections_lock);
142 static int max_nodeid;
143 static struct kmem_cache *con_cache;
144
145 static void process_recv_sockets(struct work_struct *work);
146 static void process_send_sockets(struct work_struct *work);
147
148 /*
149  * If 'allocation' is zero then we don't attempt to create a new
150  * connection structure for this node.
151  */
152 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
153 {
154         struct connection *con = NULL;
155         int r;
156         int n;
157
158         con = idr_find(&connections_idr, nodeid);
159         if (con || !alloc)
160                 return con;
161
162         r = idr_pre_get(&connections_idr, alloc);
163         if (!r)
164                 return NULL;
165
166         con = kmem_cache_zalloc(con_cache, alloc);
167         if (!con)
168                 return NULL;
169
170         r = idr_get_new_above(&connections_idr, con, nodeid, &n);
171         if (r) {
172                 kmem_cache_free(con_cache, con);
173                 return NULL;
174         }
175
176         if (n != nodeid) {
177                 idr_remove(&connections_idr, n);
178                 kmem_cache_free(con_cache, con);
179                 return NULL;
180         }
181
182         con->nodeid = nodeid;
183         mutex_init(&con->sock_mutex);
184         INIT_LIST_HEAD(&con->writequeue);
185         spin_lock_init(&con->writequeue_lock);
186         INIT_WORK(&con->swork, process_send_sockets);
187         INIT_WORK(&con->rwork, process_recv_sockets);
188
189         /* Setup action pointers for child sockets */
190         if (con->nodeid) {
191                 struct connection *zerocon = idr_find(&connections_idr, 0);
192
193                 con->connect_action = zerocon->connect_action;
194                 if (!con->rx_action)
195                         con->rx_action = zerocon->rx_action;
196         }
197
198         if (nodeid > max_nodeid)
199                 max_nodeid = nodeid;
200
201         return con;
202 }
203
204 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
205 {
206         struct connection *con;
207
208         down(&connections_lock);
209         con = __nodeid2con(nodeid, allocation);
210         up(&connections_lock);
211
212         return con;
213 }
214
215 /* This is a bit drastic, but only called when things go wrong */
216 static struct connection *assoc2con(int assoc_id)
217 {
218         int i;
219         struct connection *con;
220
221         down(&connections_lock);
222         for (i=0; i<=max_nodeid; i++) {
223                 con = __nodeid2con(i, 0);
224                 if (con && con->sctp_assoc == assoc_id) {
225                         up(&connections_lock);
226                         return con;
227                 }
228         }
229         up(&connections_lock);
230         return NULL;
231 }
232
233 static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
234 {
235         struct sockaddr_storage addr;
236         int error;
237
238         if (!dlm_local_count)
239                 return -1;
240
241         error = dlm_nodeid_to_addr(nodeid, &addr);
242         if (error)
243                 return error;
244
245         if (dlm_local_addr[0]->ss_family == AF_INET) {
246                 struct sockaddr_in *in4  = (struct sockaddr_in *) &addr;
247                 struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
248                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
249         } else {
250                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &addr;
251                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
252                 memcpy(&ret6->sin6_addr, &in6->sin6_addr,
253                        sizeof(in6->sin6_addr));
254         }
255
256         return 0;
257 }
258
259 /* Data available on socket or listen socket received a connect */
260 static void lowcomms_data_ready(struct sock *sk, int count_unused)
261 {
262         struct connection *con = sock2con(sk);
263         if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
264                 queue_work(recv_workqueue, &con->rwork);
265 }
266
267 static void lowcomms_write_space(struct sock *sk)
268 {
269         struct connection *con = sock2con(sk);
270
271         if (con && !test_and_set_bit(CF_WRITE_PENDING, &con->flags))
272                 queue_work(send_workqueue, &con->swork);
273 }
274
275 static inline void lowcomms_connect_sock(struct connection *con)
276 {
277         if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
278                 queue_work(send_workqueue, &con->swork);
279 }
280
281 static void lowcomms_state_change(struct sock *sk)
282 {
283         if (sk->sk_state == TCP_ESTABLISHED)
284                 lowcomms_write_space(sk);
285 }
286
287 /* Make a socket active */
288 static int add_sock(struct socket *sock, struct connection *con)
289 {
290         con->sock = sock;
291
292         /* Install a data_ready callback */
293         con->sock->sk->sk_data_ready = lowcomms_data_ready;
294         con->sock->sk->sk_write_space = lowcomms_write_space;
295         con->sock->sk->sk_state_change = lowcomms_state_change;
296         con->sock->sk->sk_user_data = con;
297         return 0;
298 }
299
300 /* Add the port number to an IPv6 or 4 sockaddr and return the address
301    length */
302 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
303                           int *addr_len)
304 {
305         saddr->ss_family =  dlm_local_addr[0]->ss_family;
306         if (saddr->ss_family == AF_INET) {
307                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
308                 in4_addr->sin_port = cpu_to_be16(port);
309                 *addr_len = sizeof(struct sockaddr_in);
310                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
311         } else {
312                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
313                 in6_addr->sin6_port = cpu_to_be16(port);
314                 *addr_len = sizeof(struct sockaddr_in6);
315         }
316         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
317 }
318
319 /* Close a remote connection and tidy up */
320 static void close_connection(struct connection *con, bool and_other)
321 {
322         mutex_lock(&con->sock_mutex);
323
324         if (con->sock) {
325                 sock_release(con->sock);
326                 con->sock = NULL;
327         }
328         if (con->othercon && and_other) {
329                 /* Will only re-enter once. */
330                 close_connection(con->othercon, false);
331         }
332         if (con->rx_page) {
333                 __free_page(con->rx_page);
334                 con->rx_page = NULL;
335         }
336
337         /* If we are an 'othercon' then NULL the pointer to us
338            from the parent and tidy ourself up */
339         if (test_bit(CF_IS_OTHERCON, &con->flags)) {
340                 struct connection *parent = __nodeid2con(con->nodeid, 0);
341                 parent->othercon = NULL;
342                 kmem_cache_free(con_cache, con);
343         }
344         else {
345                 /* Parent connections get reused */
346                 con->retries = 0;
347                 mutex_unlock(&con->sock_mutex);
348         }
349 }
350
351 /* We only send shutdown messages to nodes that are not part of the cluster */
352 static void sctp_send_shutdown(sctp_assoc_t associd)
353 {
354         static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
355         struct msghdr outmessage;
356         struct cmsghdr *cmsg;
357         struct sctp_sndrcvinfo *sinfo;
358         int ret;
359         struct connection *con;
360
361         con = nodeid2con(0,0);
362         BUG_ON(con == NULL);
363
364         outmessage.msg_name = NULL;
365         outmessage.msg_namelen = 0;
366         outmessage.msg_control = outcmsg;
367         outmessage.msg_controllen = sizeof(outcmsg);
368         outmessage.msg_flags = MSG_EOR;
369
370         cmsg = CMSG_FIRSTHDR(&outmessage);
371         cmsg->cmsg_level = IPPROTO_SCTP;
372         cmsg->cmsg_type = SCTP_SNDRCV;
373         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
374         outmessage.msg_controllen = cmsg->cmsg_len;
375         sinfo = CMSG_DATA(cmsg);
376         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
377
378         sinfo->sinfo_flags |= MSG_EOF;
379         sinfo->sinfo_assoc_id = associd;
380
381         ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
382
383         if (ret != 0)
384                 log_print("send EOF to node failed: %d", ret);
385 }
386
387 /* INIT failed but we don't know which node...
388    restart INIT on all pending nodes */
389 static void sctp_init_failed(void)
390 {
391         int i;
392         struct connection *con;
393
394         down(&connections_lock);
395         for (i=1; i<=max_nodeid; i++) {
396                 con = __nodeid2con(i, 0);
397                 if (!con)
398                         continue;
399                 con->sctp_assoc = 0;
400                 if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
401                         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
402                                 queue_work(send_workqueue, &con->swork);
403                         }
404                 }
405         }
406         up(&connections_lock);
407 }
408
409 /* Something happened to an association */
410 static void process_sctp_notification(struct connection *con,
411                                       struct msghdr *msg, char *buf)
412 {
413         union sctp_notification *sn = (union sctp_notification *)buf;
414
415         if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
416                 switch (sn->sn_assoc_change.sac_state) {
417
418                 case SCTP_COMM_UP:
419                 case SCTP_RESTART:
420                 {
421                         /* Check that the new node is in the lockspace */
422                         struct sctp_prim prim;
423                         int nodeid;
424                         int prim_len, ret;
425                         int addr_len;
426                         struct connection *new_con;
427                         struct file *file;
428                         sctp_peeloff_arg_t parg;
429                         int parglen = sizeof(parg);
430
431                         /*
432                          * We get this before any data for an association.
433                          * We verify that the node is in the cluster and
434                          * then peel off a socket for it.
435                          */
436                         if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
437                                 log_print("COMM_UP for invalid assoc ID %d",
438                                          (int)sn->sn_assoc_change.sac_assoc_id);
439                                 sctp_init_failed();
440                                 return;
441                         }
442                         memset(&prim, 0, sizeof(struct sctp_prim));
443                         prim_len = sizeof(struct sctp_prim);
444                         prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
445
446                         ret = kernel_getsockopt(con->sock,
447                                                 IPPROTO_SCTP,
448                                                 SCTP_PRIMARY_ADDR,
449                                                 (char*)&prim,
450                                                 &prim_len);
451                         if (ret < 0) {
452                                 log_print("getsockopt/sctp_primary_addr on "
453                                           "new assoc %d failed : %d",
454                                           (int)sn->sn_assoc_change.sac_assoc_id,
455                                           ret);
456
457                                 /* Retry INIT later */
458                                 new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
459                                 if (new_con)
460                                         clear_bit(CF_CONNECT_PENDING, &con->flags);
461                                 return;
462                         }
463                         make_sockaddr(&prim.ssp_addr, 0, &addr_len);
464                         if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
465                                 int i;
466                                 unsigned char *b=(unsigned char *)&prim.ssp_addr;
467                                 log_print("reject connect from unknown addr");
468                                 for (i=0; i<sizeof(struct sockaddr_storage);i++)
469                                         printk("%02x ", b[i]);
470                                 printk("\n");
471                                 sctp_send_shutdown(prim.ssp_assoc_id);
472                                 return;
473                         }
474
475                         new_con = nodeid2con(nodeid, GFP_KERNEL);
476                         if (!new_con)
477                                 return;
478
479                         /* Peel off a new sock */
480                         parg.associd = sn->sn_assoc_change.sac_assoc_id;
481                         ret = kernel_getsockopt(con->sock, IPPROTO_SCTP,
482                                                 SCTP_SOCKOPT_PEELOFF,
483                                                 (void *)&parg, &parglen);
484                         if (ret) {
485                                 log_print("Can't peel off a socket for "
486                                           "connection %d to node %d: err=%d\n",
487                                           parg.associd, nodeid, ret);
488                         }
489                         file = fget(parg.sd);
490                         new_con->sock = SOCKET_I(file->f_dentry->d_inode);
491                         add_sock(new_con->sock, new_con);
492                         fput(file);
493                         put_unused_fd(parg.sd);
494
495                         log_print("got new/restarted association %d nodeid %d",
496                                  (int)sn->sn_assoc_change.sac_assoc_id, nodeid);
497
498                         /* Send any pending writes */
499                         clear_bit(CF_CONNECT_PENDING, &new_con->flags);
500                         clear_bit(CF_INIT_PENDING, &con->flags);
501                         if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
502                                 queue_work(send_workqueue, &new_con->swork);
503                         }
504                         if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
505                                 queue_work(recv_workqueue, &new_con->rwork);
506                 }
507                 break;
508
509                 case SCTP_COMM_LOST:
510                 case SCTP_SHUTDOWN_COMP:
511                 {
512                         con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
513                         if (con) {
514                                 con->sctp_assoc = 0;
515                         }
516                 }
517                 break;
518
519                 /* We don't know which INIT failed, so clear the PENDING flags
520                  * on them all.  if assoc_id is zero then it will then try
521                  * again */
522
523                 case SCTP_CANT_STR_ASSOC:
524                 {
525                         log_print("Can't start SCTP association - retrying");
526                         sctp_init_failed();
527                 }
528                 break;
529
530                 default:
531                         log_print("unexpected SCTP assoc change id=%d state=%d",
532                                   (int)sn->sn_assoc_change.sac_assoc_id,
533                                   sn->sn_assoc_change.sac_state);
534                 }
535         }
536 }
537
538 /* Data received from remote end */
539 static int receive_from_sock(struct connection *con)
540 {
541         int ret = 0;
542         struct msghdr msg = {};
543         struct kvec iov[2];
544         unsigned len;
545         int r;
546         int call_again_soon = 0;
547         int nvec;
548         char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
549
550         mutex_lock(&con->sock_mutex);
551
552         if (con->sock == NULL) {
553                 ret = -EAGAIN;
554                 goto out_close;
555         }
556
557         if (con->rx_page == NULL) {
558                 /*
559                  * This doesn't need to be atomic, but I think it should
560                  * improve performance if it is.
561                  */
562                 con->rx_page = alloc_page(GFP_ATOMIC);
563                 if (con->rx_page == NULL)
564                         goto out_resched;
565                 cbuf_init(&con->cb, PAGE_CACHE_SIZE);
566         }
567
568         /* Only SCTP needs these really */
569         memset(&incmsg, 0, sizeof(incmsg));
570         msg.msg_control = incmsg;
571         msg.msg_controllen = sizeof(incmsg);
572
573         /*
574          * iov[0] is the bit of the circular buffer between the current end
575          * point (cb.base + cb.len) and the end of the buffer.
576          */
577         iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
578         iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
579         iov[1].iov_len = 0;
580         nvec = 1;
581
582         /*
583          * iov[1] is the bit of the circular buffer between the start of the
584          * buffer and the start of the currently used section (cb.base)
585          */
586         if (cbuf_data(&con->cb) >= con->cb.base) {
587                 iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
588                 iov[1].iov_len = con->cb.base;
589                 iov[1].iov_base = page_address(con->rx_page);
590                 nvec = 2;
591         }
592         len = iov[0].iov_len + iov[1].iov_len;
593
594         r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
595                                MSG_DONTWAIT | MSG_NOSIGNAL);
596         if (ret <= 0)
597                 goto out_close;
598
599         /* Process SCTP notifications */
600         if (msg.msg_flags & MSG_NOTIFICATION) {
601                 msg.msg_control = incmsg;
602                 msg.msg_controllen = sizeof(incmsg);
603
604                 process_sctp_notification(con, &msg,
605                                 page_address(con->rx_page) + con->cb.base);
606                 mutex_unlock(&con->sock_mutex);
607                 return 0;
608         }
609         BUG_ON(con->nodeid == 0);
610
611         if (ret == len)
612                 call_again_soon = 1;
613         cbuf_add(&con->cb, ret);
614         ret = dlm_process_incoming_buffer(con->nodeid,
615                                           page_address(con->rx_page),
616                                           con->cb.base, con->cb.len,
617                                           PAGE_CACHE_SIZE);
618         if (ret == -EBADMSG) {
619                 log_print("lowcomms: addr=%p, base=%u, len=%u, "
620                           "iov_len=%u, iov_base[0]=%p, read=%d",
621                           page_address(con->rx_page), con->cb.base, con->cb.len,
622                           len, iov[0].iov_base, r);
623         }
624         if (ret < 0)
625                 goto out_close;
626         cbuf_eat(&con->cb, ret);
627
628         if (cbuf_empty(&con->cb) && !call_again_soon) {
629                 __free_page(con->rx_page);
630                 con->rx_page = NULL;
631         }
632
633         if (call_again_soon)
634                 goto out_resched;
635         mutex_unlock(&con->sock_mutex);
636         return 0;
637
638 out_resched:
639         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
640                 queue_work(recv_workqueue, &con->rwork);
641         mutex_unlock(&con->sock_mutex);
642         return -EAGAIN;
643
644 out_close:
645         mutex_unlock(&con->sock_mutex);
646         if (ret != -EAGAIN) {
647                 close_connection(con, false);
648                 /* Reconnect when there is something to send */
649         }
650         /* Don't return success if we really got EOF */
651         if (ret == 0)
652                 ret = -EAGAIN;
653
654         return ret;
655 }
656
657 /* Listening socket is busy, accept a connection */
658 static int tcp_accept_from_sock(struct connection *con)
659 {
660         int result;
661         struct sockaddr_storage peeraddr;
662         struct socket *newsock;
663         int len;
664         int nodeid;
665         struct connection *newcon;
666         struct connection *addcon;
667
668         memset(&peeraddr, 0, sizeof(peeraddr));
669         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
670                                   IPPROTO_TCP, &newsock);
671         if (result < 0)
672                 return -ENOMEM;
673
674         mutex_lock_nested(&con->sock_mutex, 0);
675
676         result = -ENOTCONN;
677         if (con->sock == NULL)
678                 goto accept_err;
679
680         newsock->type = con->sock->type;
681         newsock->ops = con->sock->ops;
682
683         result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
684         if (result < 0)
685                 goto accept_err;
686
687         /* Get the connected socket's peer */
688         memset(&peeraddr, 0, sizeof(peeraddr));
689         if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
690                                   &len, 2)) {
691                 result = -ECONNABORTED;
692                 goto accept_err;
693         }
694
695         /* Get the new node's NODEID */
696         make_sockaddr(&peeraddr, 0, &len);
697         if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
698                 log_print("connect from non cluster node");
699                 sock_release(newsock);
700                 mutex_unlock(&con->sock_mutex);
701                 return -1;
702         }
703
704         log_print("got connection from %d", nodeid);
705
706         /*  Check to see if we already have a connection to this node. This
707          *  could happen if the two nodes initiate a connection at roughly
708          *  the same time and the connections cross on the wire.
709          *  In this case we store the incoming one in "othercon"
710          */
711         newcon = nodeid2con(nodeid, GFP_KERNEL);
712         if (!newcon) {
713                 result = -ENOMEM;
714                 goto accept_err;
715         }
716         mutex_lock_nested(&newcon->sock_mutex, 1);
717         if (newcon->sock) {
718                 struct connection *othercon = newcon->othercon;
719
720                 if (!othercon) {
721                         othercon = kmem_cache_zalloc(con_cache, GFP_KERNEL);
722                         if (!othercon) {
723                                 log_print("failed to allocate incoming socket");
724                                 mutex_unlock(&newcon->sock_mutex);
725                                 result = -ENOMEM;
726                                 goto accept_err;
727                         }
728                         othercon->nodeid = nodeid;
729                         othercon->rx_action = receive_from_sock;
730                         mutex_init(&othercon->sock_mutex);
731                         INIT_WORK(&othercon->swork, process_send_sockets);
732                         INIT_WORK(&othercon->rwork, process_recv_sockets);
733                         set_bit(CF_IS_OTHERCON, &othercon->flags);
734                         newcon->othercon = othercon;
735                         othercon->sock = newsock;
736                         newsock->sk->sk_user_data = othercon;
737                         add_sock(newsock, othercon);
738                         addcon = othercon;
739                 }
740                 else {
741                         printk("Extra connection from node %d attempted\n", nodeid);
742                         result = -EAGAIN;
743                         mutex_unlock(&newcon->sock_mutex);
744                         goto accept_err;
745                 }
746         }
747         else {
748                 newsock->sk->sk_user_data = newcon;
749                 newcon->rx_action = receive_from_sock;
750                 add_sock(newsock, newcon);
751                 addcon = newcon;
752         }
753
754         mutex_unlock(&newcon->sock_mutex);
755
756         /*
757          * Add it to the active queue in case we got data
758          * beween processing the accept adding the socket
759          * to the read_sockets list
760          */
761         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
762                 queue_work(recv_workqueue, &addcon->rwork);
763         mutex_unlock(&con->sock_mutex);
764
765         return 0;
766
767 accept_err:
768         mutex_unlock(&con->sock_mutex);
769         sock_release(newsock);
770
771         if (result != -EAGAIN)
772                 log_print("error accepting connection from node: %d", result);
773         return result;
774 }
775
776 static void free_entry(struct writequeue_entry *e)
777 {
778         __free_page(e->page);
779         kfree(e);
780 }
781
782 /* Initiate an SCTP association.
783    This is a special case of send_to_sock() in that we don't yet have a
784    peeled-off socket for this association, so we use the listening socket
785    and add the primary IP address of the remote node.
786  */
787 static void sctp_init_assoc(struct connection *con)
788 {
789         struct sockaddr_storage rem_addr;
790         char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
791         struct msghdr outmessage;
792         struct cmsghdr *cmsg;
793         struct sctp_sndrcvinfo *sinfo;
794         struct connection *base_con;
795         struct writequeue_entry *e;
796         int len, offset;
797         int ret;
798         int addrlen;
799         struct kvec iov[1];
800
801         if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
802                 return;
803
804         if (con->retries++ > MAX_CONNECT_RETRIES)
805                 return;
806
807         log_print("Initiating association with node %d", con->nodeid);
808
809         if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
810                 log_print("no address for nodeid %d", con->nodeid);
811                 return;
812         }
813         base_con = nodeid2con(0, 0);
814         BUG_ON(base_con == NULL);
815
816         make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
817
818         outmessage.msg_name = &rem_addr;
819         outmessage.msg_namelen = addrlen;
820         outmessage.msg_control = outcmsg;
821         outmessage.msg_controllen = sizeof(outcmsg);
822         outmessage.msg_flags = MSG_EOR;
823
824         spin_lock(&con->writequeue_lock);
825         e = list_entry(con->writequeue.next, struct writequeue_entry,
826                        list);
827
828         BUG_ON((struct list_head *) e == &con->writequeue);
829
830         len = e->len;
831         offset = e->offset;
832         spin_unlock(&con->writequeue_lock);
833         kmap(e->page);
834
835         /* Send the first block off the write queue */
836         iov[0].iov_base = page_address(e->page)+offset;
837         iov[0].iov_len = len;
838
839         cmsg = CMSG_FIRSTHDR(&outmessage);
840         cmsg->cmsg_level = IPPROTO_SCTP;
841         cmsg->cmsg_type = SCTP_SNDRCV;
842         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
843         sinfo = CMSG_DATA(cmsg);
844         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
845         sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
846         outmessage.msg_controllen = cmsg->cmsg_len;
847
848         ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
849         if (ret < 0) {
850                 log_print("Send first packet to node %d failed: %d",
851                           con->nodeid, ret);
852
853                 /* Try again later */
854                 clear_bit(CF_CONNECT_PENDING, &con->flags);
855                 clear_bit(CF_INIT_PENDING, &con->flags);
856         }
857         else {
858                 spin_lock(&con->writequeue_lock);
859                 e->offset += ret;
860                 e->len -= ret;
861
862                 if (e->len == 0 && e->users == 0) {
863                         list_del(&e->list);
864                         kunmap(e->page);
865                         free_entry(e);
866                 }
867                 spin_unlock(&con->writequeue_lock);
868         }
869 }
870
871 /* Connect a new socket to its peer */
872 static void tcp_connect_to_sock(struct connection *con)
873 {
874         int result = -EHOSTUNREACH;
875         struct sockaddr_storage saddr;
876         int addr_len;
877         struct socket *sock;
878
879         if (con->nodeid == 0) {
880                 log_print("attempt to connect sock 0 foiled");
881                 return;
882         }
883
884         mutex_lock(&con->sock_mutex);
885         if (con->retries++ > MAX_CONNECT_RETRIES)
886                 goto out;
887
888         /* Some odd races can cause double-connects, ignore them */
889         if (con->sock) {
890                 result = 0;
891                 goto out;
892         }
893
894         /* Create a socket to communicate with */
895         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
896                                   IPPROTO_TCP, &sock);
897         if (result < 0)
898                 goto out_err;
899
900         memset(&saddr, 0, sizeof(saddr));
901         if (dlm_nodeid_to_addr(con->nodeid, &saddr))
902                 goto out_err;
903
904         sock->sk->sk_user_data = con;
905         con->rx_action = receive_from_sock;
906         con->connect_action = tcp_connect_to_sock;
907         add_sock(sock, con);
908
909         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
910
911         log_print("connecting to %d", con->nodeid);
912         result =
913                 sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
914                                    O_NONBLOCK);
915         if (result == -EINPROGRESS)
916                 result = 0;
917         if (result == 0)
918                 goto out;
919
920 out_err:
921         if (con->sock) {
922                 sock_release(con->sock);
923                 con->sock = NULL;
924         }
925         /*
926          * Some errors are fatal and this list might need adjusting. For other
927          * errors we try again until the max number of retries is reached.
928          */
929         if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
930             result != -ENETDOWN && result != EINVAL
931             && result != -EPROTONOSUPPORT) {
932                 lowcomms_connect_sock(con);
933                 result = 0;
934         }
935 out:
936         mutex_unlock(&con->sock_mutex);
937         return;
938 }
939
940 static struct socket *tcp_create_listen_sock(struct connection *con,
941                                              struct sockaddr_storage *saddr)
942 {
943         struct socket *sock = NULL;
944         int result = 0;
945         int one = 1;
946         int addr_len;
947
948         if (dlm_local_addr[0]->ss_family == AF_INET)
949                 addr_len = sizeof(struct sockaddr_in);
950         else
951                 addr_len = sizeof(struct sockaddr_in6);
952
953         /* Create a socket to communicate with */
954         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
955                                   IPPROTO_TCP, &sock);
956         if (result < 0) {
957                 log_print("Can't create listening comms socket");
958                 goto create_out;
959         }
960
961         result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
962                                    (char *)&one, sizeof(one));
963
964         if (result < 0) {
965                 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
966         }
967         sock->sk->sk_user_data = con;
968         con->rx_action = tcp_accept_from_sock;
969         con->connect_action = tcp_connect_to_sock;
970         con->sock = sock;
971
972         /* Bind to our port */
973         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
974         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
975         if (result < 0) {
976                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
977                 sock_release(sock);
978                 sock = NULL;
979                 con->sock = NULL;
980                 goto create_out;
981         }
982         result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
983                                  (char *)&one, sizeof(one));
984         if (result < 0) {
985                 log_print("Set keepalive failed: %d", result);
986         }
987
988         result = sock->ops->listen(sock, 5);
989         if (result < 0) {
990                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
991                 sock_release(sock);
992                 sock = NULL;
993                 goto create_out;
994         }
995
996 create_out:
997         return sock;
998 }
999
1000 /* Get local addresses */
1001 static void init_local(void)
1002 {
1003         struct sockaddr_storage sas, *addr;
1004         int i;
1005
1006         dlm_local_count = 0;
1007         for (i = 0; i < DLM_MAX_ADDR_COUNT - 1; i++) {
1008                 if (dlm_our_addr(&sas, i))
1009                         break;
1010
1011                 addr = kmalloc(sizeof(*addr), GFP_KERNEL);
1012                 if (!addr)
1013                         break;
1014                 memcpy(addr, &sas, sizeof(*addr));
1015                 dlm_local_addr[dlm_local_count++] = addr;
1016         }
1017 }
1018
1019 /* Bind to an IP address. SCTP allows multiple address so it can do
1020    multi-homing */
1021 static int add_sctp_bind_addr(struct connection *sctp_con,
1022                               struct sockaddr_storage *addr,
1023                               int addr_len, int num)
1024 {
1025         int result = 0;
1026
1027         if (num == 1)
1028                 result = kernel_bind(sctp_con->sock,
1029                                      (struct sockaddr *) addr,
1030                                      addr_len);
1031         else
1032                 result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
1033                                            SCTP_SOCKOPT_BINDX_ADD,
1034                                            (char *)addr, addr_len);
1035
1036         if (result < 0)
1037                 log_print("Can't bind to port %d addr number %d",
1038                           dlm_config.ci_tcp_port, num);
1039
1040         return result;
1041 }
1042
1043 /* Initialise SCTP socket and bind to all interfaces */
1044 static int sctp_listen_for_all(void)
1045 {
1046         struct socket *sock = NULL;
1047         struct sockaddr_storage localaddr;
1048         struct sctp_event_subscribe subscribe;
1049         int result = -EINVAL, num = 1, i, addr_len;
1050         struct connection *con = nodeid2con(0, GFP_KERNEL);
1051         int bufsize = NEEDED_RMEM;
1052
1053         if (!con)
1054                 return -ENOMEM;
1055
1056         log_print("Using SCTP for communications");
1057
1058         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
1059                                   IPPROTO_SCTP, &sock);
1060         if (result < 0) {
1061                 log_print("Can't create comms socket, check SCTP is loaded");
1062                 goto out;
1063         }
1064
1065         /* Listen for events */
1066         memset(&subscribe, 0, sizeof(subscribe));
1067         subscribe.sctp_data_io_event = 1;
1068         subscribe.sctp_association_event = 1;
1069         subscribe.sctp_send_failure_event = 1;
1070         subscribe.sctp_shutdown_event = 1;
1071         subscribe.sctp_partial_delivery_event = 1;
1072
1073         result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
1074                                  (char *)&bufsize, sizeof(bufsize));
1075         if (result)
1076                 log_print("Error increasing buffer space on socket %d", result);
1077
1078         result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
1079                                    (char *)&subscribe, sizeof(subscribe));
1080         if (result < 0) {
1081                 log_print("Failed to set SCTP_EVENTS on socket: result=%d",
1082                           result);
1083                 goto create_delsock;
1084         }
1085
1086         /* Init con struct */
1087         sock->sk->sk_user_data = con;
1088         con->sock = sock;
1089         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1090         con->rx_action = receive_from_sock;
1091         con->connect_action = sctp_init_assoc;
1092
1093         /* Bind to all interfaces. */
1094         for (i = 0; i < dlm_local_count; i++) {
1095                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1096                 make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
1097
1098                 result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
1099                 if (result)
1100                         goto create_delsock;
1101                 ++num;
1102         }
1103
1104         result = sock->ops->listen(sock, 5);
1105         if (result < 0) {
1106                 log_print("Can't set socket listening");
1107                 goto create_delsock;
1108         }
1109
1110         return 0;
1111
1112 create_delsock:
1113         sock_release(sock);
1114         con->sock = NULL;
1115 out:
1116         return result;
1117 }
1118
1119 static int tcp_listen_for_all(void)
1120 {
1121         struct socket *sock = NULL;
1122         struct connection *con = nodeid2con(0, GFP_KERNEL);
1123         int result = -EINVAL;
1124
1125         if (!con)
1126                 return -ENOMEM;
1127
1128         /* We don't support multi-homed hosts */
1129         if (dlm_local_addr[1] != NULL) {
1130                 log_print("TCP protocol can't handle multi-homed hosts, "
1131                           "try SCTP");
1132                 return -EINVAL;
1133         }
1134
1135         log_print("Using TCP for communications");
1136
1137         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1138         if (sock) {
1139                 add_sock(sock, con);
1140                 result = 0;
1141         }
1142         else {
1143                 result = -EADDRINUSE;
1144         }
1145
1146         return result;
1147 }
1148
1149
1150
1151 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1152                                                      gfp_t allocation)
1153 {
1154         struct writequeue_entry *entry;
1155
1156         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1157         if (!entry)
1158                 return NULL;
1159
1160         entry->page = alloc_page(allocation);
1161         if (!entry->page) {
1162                 kfree(entry);
1163                 return NULL;
1164         }
1165
1166         entry->offset = 0;
1167         entry->len = 0;
1168         entry->end = 0;
1169         entry->users = 0;
1170         entry->con = con;
1171
1172         return entry;
1173 }
1174
1175 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1176 {
1177         struct connection *con;
1178         struct writequeue_entry *e;
1179         int offset = 0;
1180         int users = 0;
1181
1182         con = nodeid2con(nodeid, allocation);
1183         if (!con)
1184                 return NULL;
1185
1186         spin_lock(&con->writequeue_lock);
1187         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1188         if ((&e->list == &con->writequeue) ||
1189             (PAGE_CACHE_SIZE - e->end < len)) {
1190                 e = NULL;
1191         } else {
1192                 offset = e->end;
1193                 e->end += len;
1194                 users = e->users++;
1195         }
1196         spin_unlock(&con->writequeue_lock);
1197
1198         if (e) {
1199         got_one:
1200                 if (users == 0)
1201                         kmap(e->page);
1202                 *ppc = page_address(e->page) + offset;
1203                 return e;
1204         }
1205
1206         e = new_writequeue_entry(con, allocation);
1207         if (e) {
1208                 spin_lock(&con->writequeue_lock);
1209                 offset = e->end;
1210                 e->end += len;
1211                 users = e->users++;
1212                 list_add_tail(&e->list, &con->writequeue);
1213                 spin_unlock(&con->writequeue_lock);
1214                 goto got_one;
1215         }
1216         return NULL;
1217 }
1218
1219 void dlm_lowcomms_commit_buffer(void *mh)
1220 {
1221         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1222         struct connection *con = e->con;
1223         int users;
1224
1225         spin_lock(&con->writequeue_lock);
1226         users = --e->users;
1227         if (users)
1228                 goto out;
1229         e->len = e->end - e->offset;
1230         kunmap(e->page);
1231         spin_unlock(&con->writequeue_lock);
1232
1233         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1234                 queue_work(send_workqueue, &con->swork);
1235         }
1236         return;
1237
1238 out:
1239         spin_unlock(&con->writequeue_lock);
1240         return;
1241 }
1242
1243 /* Send a message */
1244 static void send_to_sock(struct connection *con)
1245 {
1246         int ret = 0;
1247         ssize_t(*sendpage) (struct socket *, struct page *, int, size_t, int);
1248         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1249         struct writequeue_entry *e;
1250         int len, offset;
1251
1252         mutex_lock(&con->sock_mutex);
1253         if (con->sock == NULL)
1254                 goto out_connect;
1255
1256         sendpage = con->sock->ops->sendpage;
1257
1258         spin_lock(&con->writequeue_lock);
1259         for (;;) {
1260                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1261                                list);
1262                 if ((struct list_head *) e == &con->writequeue)
1263                         break;
1264
1265                 len = e->len;
1266                 offset = e->offset;
1267                 BUG_ON(len == 0 && e->users == 0);
1268                 spin_unlock(&con->writequeue_lock);
1269                 kmap(e->page);
1270
1271                 ret = 0;
1272                 if (len) {
1273                         ret = sendpage(con->sock, e->page, offset, len,
1274                                        msg_flags);
1275                         if (ret == -EAGAIN || ret == 0)
1276                                 goto out;
1277                         if (ret <= 0)
1278                                 goto send_error;
1279                 } else {
1280                         /* Don't starve people filling buffers */
1281                         cond_resched();
1282                 }
1283
1284                 spin_lock(&con->writequeue_lock);
1285                 e->offset += ret;
1286                 e->len -= ret;
1287
1288                 if (e->len == 0 && e->users == 0) {
1289                         list_del(&e->list);
1290                         kunmap(e->page);
1291                         free_entry(e);
1292                         continue;
1293                 }
1294         }
1295         spin_unlock(&con->writequeue_lock);
1296 out:
1297         mutex_unlock(&con->sock_mutex);
1298         return;
1299
1300 send_error:
1301         mutex_unlock(&con->sock_mutex);
1302         close_connection(con, false);
1303         lowcomms_connect_sock(con);
1304         return;
1305
1306 out_connect:
1307         mutex_unlock(&con->sock_mutex);
1308         if (!test_bit(CF_INIT_PENDING, &con->flags))
1309                 lowcomms_connect_sock(con);
1310         return;
1311 }
1312
1313 static void clean_one_writequeue(struct connection *con)
1314 {
1315         struct list_head *list;
1316         struct list_head *temp;
1317
1318         spin_lock(&con->writequeue_lock);
1319         list_for_each_safe(list, temp, &con->writequeue) {
1320                 struct writequeue_entry *e =
1321                         list_entry(list, struct writequeue_entry, list);
1322                 list_del(&e->list);
1323                 free_entry(e);
1324         }
1325         spin_unlock(&con->writequeue_lock);
1326 }
1327
1328 /* Called from recovery when it knows that a node has
1329    left the cluster */
1330 int dlm_lowcomms_close(int nodeid)
1331 {
1332         struct connection *con;
1333
1334         log_print("closing connection to node %d", nodeid);
1335         con = nodeid2con(nodeid, 0);
1336         if (con) {
1337                 clean_one_writequeue(con);
1338                 close_connection(con, true);
1339         }
1340         return 0;
1341 }
1342
1343 /* Receive workqueue function */
1344 static void process_recv_sockets(struct work_struct *work)
1345 {
1346         struct connection *con = container_of(work, struct connection, rwork);
1347         int err;
1348
1349         clear_bit(CF_READ_PENDING, &con->flags);
1350         do {
1351                 err = con->rx_action(con);
1352         } while (!err);
1353 }
1354
1355 /* Send workqueue function */
1356 static void process_send_sockets(struct work_struct *work)
1357 {
1358         struct connection *con = container_of(work, struct connection, swork);
1359
1360         if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1361                 con->connect_action(con);
1362         }
1363         clear_bit(CF_WRITE_PENDING, &con->flags);
1364         send_to_sock(con);
1365 }
1366
1367
1368 /* Discard all entries on the write queues */
1369 static void clean_writequeues(void)
1370 {
1371         int nodeid;
1372
1373         for (nodeid = 1; nodeid <= max_nodeid; nodeid++) {
1374                 struct connection *con = __nodeid2con(nodeid, 0);
1375
1376                 if (con)
1377                         clean_one_writequeue(con);
1378         }
1379 }
1380
1381 static void work_stop(void)
1382 {
1383         destroy_workqueue(recv_workqueue);
1384         destroy_workqueue(send_workqueue);
1385 }
1386
1387 static int work_start(void)
1388 {
1389         int error;
1390         recv_workqueue = create_workqueue("dlm_recv");
1391         error = IS_ERR(recv_workqueue);
1392         if (error) {
1393                 log_print("can't start dlm_recv %d", error);
1394                 return error;
1395         }
1396
1397         send_workqueue = create_singlethread_workqueue("dlm_send");
1398         error = IS_ERR(send_workqueue);
1399         if (error) {
1400                 log_print("can't start dlm_send %d", error);
1401                 destroy_workqueue(recv_workqueue);
1402                 return error;
1403         }
1404
1405         return 0;
1406 }
1407
1408 void dlm_lowcomms_stop(void)
1409 {
1410         int i;
1411         struct connection *con;
1412
1413         /* Set all the flags to prevent any
1414            socket activity.
1415         */
1416         down(&connections_lock);
1417         for (i = 0; i <= max_nodeid; i++) {
1418                 con = __nodeid2con(i, 0);
1419                 if (con) {
1420                         con->flags |= 0x0F;
1421                         if (con->sock)
1422                                 con->sock->sk->sk_user_data = NULL;
1423                 }
1424         }
1425         up(&connections_lock);
1426
1427         work_stop();
1428
1429         down(&connections_lock);
1430         clean_writequeues();
1431
1432         for (i = 0; i <= max_nodeid; i++) {
1433                 con = __nodeid2con(i, 0);
1434                 if (con) {
1435                         close_connection(con, true);
1436                         kmem_cache_free(con_cache, con);
1437                 }
1438         }
1439         max_nodeid = 0;
1440         up(&connections_lock);
1441         kmem_cache_destroy(con_cache);
1442         idr_init(&connections_idr);
1443 }
1444
1445 int dlm_lowcomms_start(void)
1446 {
1447         int error = -EINVAL;
1448         struct connection *con;
1449
1450         init_local();
1451         if (!dlm_local_count) {
1452                 error = -ENOTCONN;
1453                 log_print("no local IP address has been set");
1454                 goto out;
1455         }
1456
1457         error = -ENOMEM;
1458         con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1459                                       __alignof__(struct connection), 0,
1460                                       NULL);
1461         if (!con_cache)
1462                 goto out;
1463
1464         /* Set some sysctl minima */
1465         if (sysctl_rmem_max < NEEDED_RMEM)
1466                 sysctl_rmem_max = NEEDED_RMEM;
1467
1468         /* Start listening */
1469         if (dlm_config.ci_protocol == 0)
1470                 error = tcp_listen_for_all();
1471         else
1472                 error = sctp_listen_for_all();
1473         if (error)
1474                 goto fail_unlisten;
1475
1476         error = work_start();
1477         if (error)
1478                 goto fail_unlisten;
1479
1480         return 0;
1481
1482 fail_unlisten:
1483         con = nodeid2con(0,0);
1484         if (con) {
1485                 close_connection(con, false);
1486                 kmem_cache_free(con_cache, con);
1487         }
1488         kmem_cache_destroy(con_cache);
1489
1490 out:
1491         return error;
1492 }