dlm: fix QUECVT when convert queue is empty
[linux-3.10.git] / fs / dlm / lowcomms.c
1 /******************************************************************************
2 *******************************************************************************
3 **
4 **  Copyright (C) Sistina Software, Inc.  1997-2003  All rights reserved.
5 **  Copyright (C) 2004-2009 Red Hat, Inc.  All rights reserved.
6 **
7 **  This copyrighted material is made available to anyone wishing to use,
8 **  modify, copy, or redistribute it subject to the terms and conditions
9 **  of the GNU General Public License v.2.
10 **
11 *******************************************************************************
12 ******************************************************************************/
13
14 /*
15  * lowcomms.c
16  *
17  * This is the "low-level" comms layer.
18  *
19  * It is responsible for sending/receiving messages
20  * from other nodes in the cluster.
21  *
22  * Cluster nodes are referred to by their nodeids. nodeids are
23  * simply 32 bit numbers to the locking module - if they need to
24  * be expanded for the cluster infrastructure then that is its
25  * responsibility. It is this layer's
26  * responsibility to resolve these into IP address or
27  * whatever it needs for inter-node communication.
28  *
29  * The comms level is two kernel threads that deal mainly with
30  * the receiving of messages from other nodes and passing them
31  * up to the mid-level comms layer (which understands the
32  * message format) for execution by the locking core, and
33  * a send thread which does all the setting up of connections
34  * to remote nodes and the sending of data. Threads are not allowed
35  * to send their own data because it may cause them to wait in times
36  * of high load. Also, this way, the sending thread can collect together
37  * messages bound for one node and send them in one block.
38  *
39  * lowcomms will choose to use either TCP or SCTP as its transport layer
40  * depending on the configuration variable 'protocol'. This should be set
41  * to 0 (default) for TCP or 1 for SCTP. It should be configured using a
42  * cluster-wide mechanism as it must be the same on all nodes of the cluster
43  * for the DLM to function.
44  *
45  */
46
47 #include <asm/ioctls.h>
48 #include <net/sock.h>
49 #include <net/tcp.h>
50 #include <linux/pagemap.h>
51 #include <linux/file.h>
52 #include <linux/mutex.h>
53 #include <linux/sctp.h>
54 #include <linux/slab.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/user.h>
57 #include <net/ipv6.h>
58
59 #include "dlm_internal.h"
60 #include "lowcomms.h"
61 #include "midcomms.h"
62 #include "config.h"
63
64 #define NEEDED_RMEM (4*1024*1024)
65 #define CONN_HASH_SIZE 32
66
67 /* Number of messages to send before rescheduling */
68 #define MAX_SEND_MSG_COUNT 25
69
70 struct cbuf {
71         unsigned int base;
72         unsigned int len;
73         unsigned int mask;
74 };
75
76 static void cbuf_add(struct cbuf *cb, int n)
77 {
78         cb->len += n;
79 }
80
81 static int cbuf_data(struct cbuf *cb)
82 {
83         return ((cb->base + cb->len) & cb->mask);
84 }
85
86 static void cbuf_init(struct cbuf *cb, int size)
87 {
88         cb->base = cb->len = 0;
89         cb->mask = size-1;
90 }
91
92 static void cbuf_eat(struct cbuf *cb, int n)
93 {
94         cb->len  -= n;
95         cb->base += n;
96         cb->base &= cb->mask;
97 }
98
99 static bool cbuf_empty(struct cbuf *cb)
100 {
101         return cb->len == 0;
102 }
103
104 struct connection {
105         struct socket *sock;    /* NULL if not connected */
106         uint32_t nodeid;        /* So we know who we are in the list */
107         struct mutex sock_mutex;
108         unsigned long flags;
109 #define CF_READ_PENDING 1
110 #define CF_WRITE_PENDING 2
111 #define CF_CONNECT_PENDING 3
112 #define CF_INIT_PENDING 4
113 #define CF_IS_OTHERCON 5
114 #define CF_CLOSE 6
115 #define CF_APP_LIMITED 7
116         struct list_head writequeue;  /* List of outgoing writequeue_entries */
117         spinlock_t writequeue_lock;
118         int (*rx_action) (struct connection *); /* What to do when active */
119         void (*connect_action) (struct connection *);   /* What to do to connect */
120         struct page *rx_page;
121         struct cbuf cb;
122         int retries;
123 #define MAX_CONNECT_RETRIES 3
124         int sctp_assoc;
125         struct hlist_node list;
126         struct connection *othercon;
127         struct work_struct rwork; /* Receive workqueue */
128         struct work_struct swork; /* Send workqueue */
129 };
130 #define sock2con(x) ((struct connection *)(x)->sk_user_data)
131
132 /* An entry waiting to be sent */
133 struct writequeue_entry {
134         struct list_head list;
135         struct page *page;
136         int offset;
137         int len;
138         int end;
139         int users;
140         struct connection *con;
141 };
142
143 static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];
144 static int dlm_local_count;
145
146 /* Work queues */
147 static struct workqueue_struct *recv_workqueue;
148 static struct workqueue_struct *send_workqueue;
149
150 static struct hlist_head connection_hash[CONN_HASH_SIZE];
151 static DEFINE_MUTEX(connections_lock);
152 static struct kmem_cache *con_cache;
153
154 static void process_recv_sockets(struct work_struct *work);
155 static void process_send_sockets(struct work_struct *work);
156
157
158 /* This is deliberately very simple because most clusters have simple
159    sequential nodeids, so we should be able to go straight to a connection
160    struct in the array */
161 static inline int nodeid_hash(int nodeid)
162 {
163         return nodeid & (CONN_HASH_SIZE-1);
164 }
165
166 static struct connection *__find_con(int nodeid)
167 {
168         int r;
169         struct hlist_node *h;
170         struct connection *con;
171
172         r = nodeid_hash(nodeid);
173
174         hlist_for_each_entry(con, h, &connection_hash[r], list) {
175                 if (con->nodeid == nodeid)
176                         return con;
177         }
178         return NULL;
179 }
180
181 /*
182  * If 'allocation' is zero then we don't attempt to create a new
183  * connection structure for this node.
184  */
185 static struct connection *__nodeid2con(int nodeid, gfp_t alloc)
186 {
187         struct connection *con = NULL;
188         int r;
189
190         con = __find_con(nodeid);
191         if (con || !alloc)
192                 return con;
193
194         con = kmem_cache_zalloc(con_cache, alloc);
195         if (!con)
196                 return NULL;
197
198         r = nodeid_hash(nodeid);
199         hlist_add_head(&con->list, &connection_hash[r]);
200
201         con->nodeid = nodeid;
202         mutex_init(&con->sock_mutex);
203         INIT_LIST_HEAD(&con->writequeue);
204         spin_lock_init(&con->writequeue_lock);
205         INIT_WORK(&con->swork, process_send_sockets);
206         INIT_WORK(&con->rwork, process_recv_sockets);
207
208         /* Setup action pointers for child sockets */
209         if (con->nodeid) {
210                 struct connection *zerocon = __find_con(0);
211
212                 con->connect_action = zerocon->connect_action;
213                 if (!con->rx_action)
214                         con->rx_action = zerocon->rx_action;
215         }
216
217         return con;
218 }
219
220 /* Loop round all connections */
221 static void foreach_conn(void (*conn_func)(struct connection *c))
222 {
223         int i;
224         struct hlist_node *h, *n;
225         struct connection *con;
226
227         for (i = 0; i < CONN_HASH_SIZE; i++) {
228                 hlist_for_each_entry_safe(con, h, n, &connection_hash[i], list){
229                         conn_func(con);
230                 }
231         }
232 }
233
234 static struct connection *nodeid2con(int nodeid, gfp_t allocation)
235 {
236         struct connection *con;
237
238         mutex_lock(&connections_lock);
239         con = __nodeid2con(nodeid, allocation);
240         mutex_unlock(&connections_lock);
241
242         return con;
243 }
244
245 /* This is a bit drastic, but only called when things go wrong */
246 static struct connection *assoc2con(int assoc_id)
247 {
248         int i;
249         struct hlist_node *h;
250         struct connection *con;
251
252         mutex_lock(&connections_lock);
253
254         for (i = 0 ; i < CONN_HASH_SIZE; i++) {
255                 hlist_for_each_entry(con, h, &connection_hash[i], list) {
256                         if (con->sctp_assoc == assoc_id) {
257                                 mutex_unlock(&connections_lock);
258                                 return con;
259                         }
260                 }
261         }
262         mutex_unlock(&connections_lock);
263         return NULL;
264 }
265
266 static int nodeid_to_addr(int nodeid, struct sockaddr *retaddr)
267 {
268         struct sockaddr_storage addr;
269         int error;
270
271         if (!dlm_local_count)
272                 return -1;
273
274         error = dlm_nodeid_to_addr(nodeid, &addr);
275         if (error)
276                 return error;
277
278         if (dlm_local_addr[0]->ss_family == AF_INET) {
279                 struct sockaddr_in *in4  = (struct sockaddr_in *) &addr;
280                 struct sockaddr_in *ret4 = (struct sockaddr_in *) retaddr;
281                 ret4->sin_addr.s_addr = in4->sin_addr.s_addr;
282         } else {
283                 struct sockaddr_in6 *in6  = (struct sockaddr_in6 *) &addr;
284                 struct sockaddr_in6 *ret6 = (struct sockaddr_in6 *) retaddr;
285                 ret6->sin6_addr = in6->sin6_addr;
286         }
287
288         return 0;
289 }
290
291 /* Data available on socket or listen socket received a connect */
292 static void lowcomms_data_ready(struct sock *sk, int count_unused)
293 {
294         struct connection *con = sock2con(sk);
295         if (con && !test_and_set_bit(CF_READ_PENDING, &con->flags))
296                 queue_work(recv_workqueue, &con->rwork);
297 }
298
299 static void lowcomms_write_space(struct sock *sk)
300 {
301         struct connection *con = sock2con(sk);
302
303         if (!con)
304                 return;
305
306         clear_bit(SOCK_NOSPACE, &con->sock->flags);
307
308         if (test_and_clear_bit(CF_APP_LIMITED, &con->flags)) {
309                 con->sock->sk->sk_write_pending--;
310                 clear_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags);
311         }
312
313         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
314                 queue_work(send_workqueue, &con->swork);
315 }
316
317 static inline void lowcomms_connect_sock(struct connection *con)
318 {
319         if (test_bit(CF_CLOSE, &con->flags))
320                 return;
321         if (!test_and_set_bit(CF_CONNECT_PENDING, &con->flags))
322                 queue_work(send_workqueue, &con->swork);
323 }
324
325 static void lowcomms_state_change(struct sock *sk)
326 {
327         if (sk->sk_state == TCP_ESTABLISHED)
328                 lowcomms_write_space(sk);
329 }
330
331 int dlm_lowcomms_connect_node(int nodeid)
332 {
333         struct connection *con;
334
335         /* with sctp there's no connecting without sending */
336         if (dlm_config.ci_protocol != 0)
337                 return 0;
338
339         if (nodeid == dlm_our_nodeid())
340                 return 0;
341
342         con = nodeid2con(nodeid, GFP_NOFS);
343         if (!con)
344                 return -ENOMEM;
345         lowcomms_connect_sock(con);
346         return 0;
347 }
348
349 /* Make a socket active */
350 static int add_sock(struct socket *sock, struct connection *con)
351 {
352         con->sock = sock;
353
354         /* Install a data_ready callback */
355         con->sock->sk->sk_data_ready = lowcomms_data_ready;
356         con->sock->sk->sk_write_space = lowcomms_write_space;
357         con->sock->sk->sk_state_change = lowcomms_state_change;
358         con->sock->sk->sk_user_data = con;
359         con->sock->sk->sk_allocation = GFP_NOFS;
360         return 0;
361 }
362
363 /* Add the port number to an IPv6 or 4 sockaddr and return the address
364    length */
365 static void make_sockaddr(struct sockaddr_storage *saddr, uint16_t port,
366                           int *addr_len)
367 {
368         saddr->ss_family =  dlm_local_addr[0]->ss_family;
369         if (saddr->ss_family == AF_INET) {
370                 struct sockaddr_in *in4_addr = (struct sockaddr_in *)saddr;
371                 in4_addr->sin_port = cpu_to_be16(port);
372                 *addr_len = sizeof(struct sockaddr_in);
373                 memset(&in4_addr->sin_zero, 0, sizeof(in4_addr->sin_zero));
374         } else {
375                 struct sockaddr_in6 *in6_addr = (struct sockaddr_in6 *)saddr;
376                 in6_addr->sin6_port = cpu_to_be16(port);
377                 *addr_len = sizeof(struct sockaddr_in6);
378         }
379         memset((char *)saddr + *addr_len, 0, sizeof(struct sockaddr_storage) - *addr_len);
380 }
381
382 /* Close a remote connection and tidy up */
383 static void close_connection(struct connection *con, bool and_other)
384 {
385         mutex_lock(&con->sock_mutex);
386
387         if (con->sock) {
388                 sock_release(con->sock);
389                 con->sock = NULL;
390         }
391         if (con->othercon && and_other) {
392                 /* Will only re-enter once. */
393                 close_connection(con->othercon, false);
394         }
395         if (con->rx_page) {
396                 __free_page(con->rx_page);
397                 con->rx_page = NULL;
398         }
399
400         con->retries = 0;
401         mutex_unlock(&con->sock_mutex);
402 }
403
404 /* We only send shutdown messages to nodes that are not part of the cluster */
405 static void sctp_send_shutdown(sctp_assoc_t associd)
406 {
407         static char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
408         struct msghdr outmessage;
409         struct cmsghdr *cmsg;
410         struct sctp_sndrcvinfo *sinfo;
411         int ret;
412         struct connection *con;
413
414         con = nodeid2con(0,0);
415         BUG_ON(con == NULL);
416
417         outmessage.msg_name = NULL;
418         outmessage.msg_namelen = 0;
419         outmessage.msg_control = outcmsg;
420         outmessage.msg_controllen = sizeof(outcmsg);
421         outmessage.msg_flags = MSG_EOR;
422
423         cmsg = CMSG_FIRSTHDR(&outmessage);
424         cmsg->cmsg_level = IPPROTO_SCTP;
425         cmsg->cmsg_type = SCTP_SNDRCV;
426         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
427         outmessage.msg_controllen = cmsg->cmsg_len;
428         sinfo = CMSG_DATA(cmsg);
429         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
430
431         sinfo->sinfo_flags |= MSG_EOF;
432         sinfo->sinfo_assoc_id = associd;
433
434         ret = kernel_sendmsg(con->sock, &outmessage, NULL, 0, 0);
435
436         if (ret != 0)
437                 log_print("send EOF to node failed: %d", ret);
438 }
439
440 static void sctp_init_failed_foreach(struct connection *con)
441 {
442         con->sctp_assoc = 0;
443         if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
444                 if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags))
445                         queue_work(send_workqueue, &con->swork);
446         }
447 }
448
449 /* INIT failed but we don't know which node...
450    restart INIT on all pending nodes */
451 static void sctp_init_failed(void)
452 {
453         mutex_lock(&connections_lock);
454
455         foreach_conn(sctp_init_failed_foreach);
456
457         mutex_unlock(&connections_lock);
458 }
459
460 /* Something happened to an association */
461 static void process_sctp_notification(struct connection *con,
462                                       struct msghdr *msg, char *buf)
463 {
464         union sctp_notification *sn = (union sctp_notification *)buf;
465
466         if (sn->sn_header.sn_type == SCTP_ASSOC_CHANGE) {
467                 switch (sn->sn_assoc_change.sac_state) {
468
469                 case SCTP_COMM_UP:
470                 case SCTP_RESTART:
471                 {
472                         /* Check that the new node is in the lockspace */
473                         struct sctp_prim prim;
474                         int nodeid;
475                         int prim_len, ret;
476                         int addr_len;
477                         struct connection *new_con;
478
479                         /*
480                          * We get this before any data for an association.
481                          * We verify that the node is in the cluster and
482                          * then peel off a socket for it.
483                          */
484                         if ((int)sn->sn_assoc_change.sac_assoc_id <= 0) {
485                                 log_print("COMM_UP for invalid assoc ID %d",
486                                          (int)sn->sn_assoc_change.sac_assoc_id);
487                                 sctp_init_failed();
488                                 return;
489                         }
490                         memset(&prim, 0, sizeof(struct sctp_prim));
491                         prim_len = sizeof(struct sctp_prim);
492                         prim.ssp_assoc_id = sn->sn_assoc_change.sac_assoc_id;
493
494                         ret = kernel_getsockopt(con->sock,
495                                                 IPPROTO_SCTP,
496                                                 SCTP_PRIMARY_ADDR,
497                                                 (char*)&prim,
498                                                 &prim_len);
499                         if (ret < 0) {
500                                 log_print("getsockopt/sctp_primary_addr on "
501                                           "new assoc %d failed : %d",
502                                           (int)sn->sn_assoc_change.sac_assoc_id,
503                                           ret);
504
505                                 /* Retry INIT later */
506                                 new_con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
507                                 if (new_con)
508                                         clear_bit(CF_CONNECT_PENDING, &con->flags);
509                                 return;
510                         }
511                         make_sockaddr(&prim.ssp_addr, 0, &addr_len);
512                         if (dlm_addr_to_nodeid(&prim.ssp_addr, &nodeid)) {
513                                 unsigned char *b=(unsigned char *)&prim.ssp_addr;
514                                 log_print("reject connect from unknown addr");
515                                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 
516                                                      b, sizeof(struct sockaddr_storage));
517                                 sctp_send_shutdown(prim.ssp_assoc_id);
518                                 return;
519                         }
520
521                         new_con = nodeid2con(nodeid, GFP_NOFS);
522                         if (!new_con)
523                                 return;
524
525                         /* Peel off a new sock */
526                         sctp_lock_sock(con->sock->sk);
527                         ret = sctp_do_peeloff(con->sock->sk,
528                                 sn->sn_assoc_change.sac_assoc_id,
529                                 &new_con->sock);
530                         sctp_release_sock(con->sock->sk);
531                         if (ret < 0) {
532                                 log_print("Can't peel off a socket for "
533                                           "connection %d to node %d: err=%d",
534                                           (int)sn->sn_assoc_change.sac_assoc_id,
535                                           nodeid, ret);
536                                 return;
537                         }
538                         add_sock(new_con->sock, new_con);
539
540                         log_print("connecting to %d sctp association %d",
541                                  nodeid, (int)sn->sn_assoc_change.sac_assoc_id);
542
543                         /* Send any pending writes */
544                         clear_bit(CF_CONNECT_PENDING, &new_con->flags);
545                         clear_bit(CF_INIT_PENDING, &con->flags);
546                         if (!test_and_set_bit(CF_WRITE_PENDING, &new_con->flags)) {
547                                 queue_work(send_workqueue, &new_con->swork);
548                         }
549                         if (!test_and_set_bit(CF_READ_PENDING, &new_con->flags))
550                                 queue_work(recv_workqueue, &new_con->rwork);
551                 }
552                 break;
553
554                 case SCTP_COMM_LOST:
555                 case SCTP_SHUTDOWN_COMP:
556                 {
557                         con = assoc2con(sn->sn_assoc_change.sac_assoc_id);
558                         if (con) {
559                                 con->sctp_assoc = 0;
560                         }
561                 }
562                 break;
563
564                 /* We don't know which INIT failed, so clear the PENDING flags
565                  * on them all.  if assoc_id is zero then it will then try
566                  * again */
567
568                 case SCTP_CANT_STR_ASSOC:
569                 {
570                         log_print("Can't start SCTP association - retrying");
571                         sctp_init_failed();
572                 }
573                 break;
574
575                 default:
576                         log_print("unexpected SCTP assoc change id=%d state=%d",
577                                   (int)sn->sn_assoc_change.sac_assoc_id,
578                                   sn->sn_assoc_change.sac_state);
579                 }
580         }
581 }
582
583 /* Data received from remote end */
584 static int receive_from_sock(struct connection *con)
585 {
586         int ret = 0;
587         struct msghdr msg = {};
588         struct kvec iov[2];
589         unsigned len;
590         int r;
591         int call_again_soon = 0;
592         int nvec;
593         char incmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
594
595         mutex_lock(&con->sock_mutex);
596
597         if (con->sock == NULL) {
598                 ret = -EAGAIN;
599                 goto out_close;
600         }
601
602         if (con->rx_page == NULL) {
603                 /*
604                  * This doesn't need to be atomic, but I think it should
605                  * improve performance if it is.
606                  */
607                 con->rx_page = alloc_page(GFP_ATOMIC);
608                 if (con->rx_page == NULL)
609                         goto out_resched;
610                 cbuf_init(&con->cb, PAGE_CACHE_SIZE);
611         }
612
613         /* Only SCTP needs these really */
614         memset(&incmsg, 0, sizeof(incmsg));
615         msg.msg_control = incmsg;
616         msg.msg_controllen = sizeof(incmsg);
617
618         /*
619          * iov[0] is the bit of the circular buffer between the current end
620          * point (cb.base + cb.len) and the end of the buffer.
621          */
622         iov[0].iov_len = con->cb.base - cbuf_data(&con->cb);
623         iov[0].iov_base = page_address(con->rx_page) + cbuf_data(&con->cb);
624         iov[1].iov_len = 0;
625         nvec = 1;
626
627         /*
628          * iov[1] is the bit of the circular buffer between the start of the
629          * buffer and the start of the currently used section (cb.base)
630          */
631         if (cbuf_data(&con->cb) >= con->cb.base) {
632                 iov[0].iov_len = PAGE_CACHE_SIZE - cbuf_data(&con->cb);
633                 iov[1].iov_len = con->cb.base;
634                 iov[1].iov_base = page_address(con->rx_page);
635                 nvec = 2;
636         }
637         len = iov[0].iov_len + iov[1].iov_len;
638
639         r = ret = kernel_recvmsg(con->sock, &msg, iov, nvec, len,
640                                MSG_DONTWAIT | MSG_NOSIGNAL);
641         if (ret <= 0)
642                 goto out_close;
643
644         /* Process SCTP notifications */
645         if (msg.msg_flags & MSG_NOTIFICATION) {
646                 msg.msg_control = incmsg;
647                 msg.msg_controllen = sizeof(incmsg);
648
649                 process_sctp_notification(con, &msg,
650                                 page_address(con->rx_page) + con->cb.base);
651                 mutex_unlock(&con->sock_mutex);
652                 return 0;
653         }
654         BUG_ON(con->nodeid == 0);
655
656         if (ret == len)
657                 call_again_soon = 1;
658         cbuf_add(&con->cb, ret);
659         ret = dlm_process_incoming_buffer(con->nodeid,
660                                           page_address(con->rx_page),
661                                           con->cb.base, con->cb.len,
662                                           PAGE_CACHE_SIZE);
663         if (ret == -EBADMSG) {
664                 log_print("lowcomms: addr=%p, base=%u, len=%u, "
665                           "iov_len=%u, iov_base[0]=%p, read=%d",
666                           page_address(con->rx_page), con->cb.base, con->cb.len,
667                           len, iov[0].iov_base, r);
668         }
669         if (ret < 0)
670                 goto out_close;
671         cbuf_eat(&con->cb, ret);
672
673         if (cbuf_empty(&con->cb) && !call_again_soon) {
674                 __free_page(con->rx_page);
675                 con->rx_page = NULL;
676         }
677
678         if (call_again_soon)
679                 goto out_resched;
680         mutex_unlock(&con->sock_mutex);
681         return 0;
682
683 out_resched:
684         if (!test_and_set_bit(CF_READ_PENDING, &con->flags))
685                 queue_work(recv_workqueue, &con->rwork);
686         mutex_unlock(&con->sock_mutex);
687         return -EAGAIN;
688
689 out_close:
690         mutex_unlock(&con->sock_mutex);
691         if (ret != -EAGAIN) {
692                 close_connection(con, false);
693                 /* Reconnect when there is something to send */
694         }
695         /* Don't return success if we really got EOF */
696         if (ret == 0)
697                 ret = -EAGAIN;
698
699         return ret;
700 }
701
702 /* Listening socket is busy, accept a connection */
703 static int tcp_accept_from_sock(struct connection *con)
704 {
705         int result;
706         struct sockaddr_storage peeraddr;
707         struct socket *newsock;
708         int len;
709         int nodeid;
710         struct connection *newcon;
711         struct connection *addcon;
712
713         memset(&peeraddr, 0, sizeof(peeraddr));
714         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
715                                   IPPROTO_TCP, &newsock);
716         if (result < 0)
717                 return -ENOMEM;
718
719         mutex_lock_nested(&con->sock_mutex, 0);
720
721         result = -ENOTCONN;
722         if (con->sock == NULL)
723                 goto accept_err;
724
725         newsock->type = con->sock->type;
726         newsock->ops = con->sock->ops;
727
728         result = con->sock->ops->accept(con->sock, newsock, O_NONBLOCK);
729         if (result < 0)
730                 goto accept_err;
731
732         /* Get the connected socket's peer */
733         memset(&peeraddr, 0, sizeof(peeraddr));
734         if (newsock->ops->getname(newsock, (struct sockaddr *)&peeraddr,
735                                   &len, 2)) {
736                 result = -ECONNABORTED;
737                 goto accept_err;
738         }
739
740         /* Get the new node's NODEID */
741         make_sockaddr(&peeraddr, 0, &len);
742         if (dlm_addr_to_nodeid(&peeraddr, &nodeid)) {
743                 unsigned char *b=(unsigned char *)&peeraddr;
744                 log_print("connect from non cluster node");
745                 print_hex_dump_bytes("ss: ", DUMP_PREFIX_NONE, 
746                                      b, sizeof(struct sockaddr_storage));
747                 sock_release(newsock);
748                 mutex_unlock(&con->sock_mutex);
749                 return -1;
750         }
751
752         log_print("got connection from %d", nodeid);
753
754         /*  Check to see if we already have a connection to this node. This
755          *  could happen if the two nodes initiate a connection at roughly
756          *  the same time and the connections cross on the wire.
757          *  In this case we store the incoming one in "othercon"
758          */
759         newcon = nodeid2con(nodeid, GFP_NOFS);
760         if (!newcon) {
761                 result = -ENOMEM;
762                 goto accept_err;
763         }
764         mutex_lock_nested(&newcon->sock_mutex, 1);
765         if (newcon->sock) {
766                 struct connection *othercon = newcon->othercon;
767
768                 if (!othercon) {
769                         othercon = kmem_cache_zalloc(con_cache, GFP_NOFS);
770                         if (!othercon) {
771                                 log_print("failed to allocate incoming socket");
772                                 mutex_unlock(&newcon->sock_mutex);
773                                 result = -ENOMEM;
774                                 goto accept_err;
775                         }
776                         othercon->nodeid = nodeid;
777                         othercon->rx_action = receive_from_sock;
778                         mutex_init(&othercon->sock_mutex);
779                         INIT_WORK(&othercon->swork, process_send_sockets);
780                         INIT_WORK(&othercon->rwork, process_recv_sockets);
781                         set_bit(CF_IS_OTHERCON, &othercon->flags);
782                 }
783                 if (!othercon->sock) {
784                         newcon->othercon = othercon;
785                         othercon->sock = newsock;
786                         newsock->sk->sk_user_data = othercon;
787                         add_sock(newsock, othercon);
788                         addcon = othercon;
789                 }
790                 else {
791                         printk("Extra connection from node %d attempted\n", nodeid);
792                         result = -EAGAIN;
793                         mutex_unlock(&newcon->sock_mutex);
794                         goto accept_err;
795                 }
796         }
797         else {
798                 newsock->sk->sk_user_data = newcon;
799                 newcon->rx_action = receive_from_sock;
800                 add_sock(newsock, newcon);
801                 addcon = newcon;
802         }
803
804         mutex_unlock(&newcon->sock_mutex);
805
806         /*
807          * Add it to the active queue in case we got data
808          * between processing the accept adding the socket
809          * to the read_sockets list
810          */
811         if (!test_and_set_bit(CF_READ_PENDING, &addcon->flags))
812                 queue_work(recv_workqueue, &addcon->rwork);
813         mutex_unlock(&con->sock_mutex);
814
815         return 0;
816
817 accept_err:
818         mutex_unlock(&con->sock_mutex);
819         sock_release(newsock);
820
821         if (result != -EAGAIN)
822                 log_print("error accepting connection from node: %d", result);
823         return result;
824 }
825
826 static void free_entry(struct writequeue_entry *e)
827 {
828         __free_page(e->page);
829         kfree(e);
830 }
831
832 /* Initiate an SCTP association.
833    This is a special case of send_to_sock() in that we don't yet have a
834    peeled-off socket for this association, so we use the listening socket
835    and add the primary IP address of the remote node.
836  */
837 static void sctp_init_assoc(struct connection *con)
838 {
839         struct sockaddr_storage rem_addr;
840         char outcmsg[CMSG_SPACE(sizeof(struct sctp_sndrcvinfo))];
841         struct msghdr outmessage;
842         struct cmsghdr *cmsg;
843         struct sctp_sndrcvinfo *sinfo;
844         struct connection *base_con;
845         struct writequeue_entry *e;
846         int len, offset;
847         int ret;
848         int addrlen;
849         struct kvec iov[1];
850
851         if (test_and_set_bit(CF_INIT_PENDING, &con->flags))
852                 return;
853
854         if (con->retries++ > MAX_CONNECT_RETRIES)
855                 return;
856
857         if (nodeid_to_addr(con->nodeid, (struct sockaddr *)&rem_addr)) {
858                 log_print("no address for nodeid %d", con->nodeid);
859                 return;
860         }
861         base_con = nodeid2con(0, 0);
862         BUG_ON(base_con == NULL);
863
864         make_sockaddr(&rem_addr, dlm_config.ci_tcp_port, &addrlen);
865
866         outmessage.msg_name = &rem_addr;
867         outmessage.msg_namelen = addrlen;
868         outmessage.msg_control = outcmsg;
869         outmessage.msg_controllen = sizeof(outcmsg);
870         outmessage.msg_flags = MSG_EOR;
871
872         spin_lock(&con->writequeue_lock);
873
874         if (list_empty(&con->writequeue)) {
875                 spin_unlock(&con->writequeue_lock);
876                 log_print("writequeue empty for nodeid %d", con->nodeid);
877                 return;
878         }
879
880         e = list_first_entry(&con->writequeue, struct writequeue_entry, list);
881         len = e->len;
882         offset = e->offset;
883         spin_unlock(&con->writequeue_lock);
884
885         /* Send the first block off the write queue */
886         iov[0].iov_base = page_address(e->page)+offset;
887         iov[0].iov_len = len;
888
889         cmsg = CMSG_FIRSTHDR(&outmessage);
890         cmsg->cmsg_level = IPPROTO_SCTP;
891         cmsg->cmsg_type = SCTP_SNDRCV;
892         cmsg->cmsg_len = CMSG_LEN(sizeof(struct sctp_sndrcvinfo));
893         sinfo = CMSG_DATA(cmsg);
894         memset(sinfo, 0x00, sizeof(struct sctp_sndrcvinfo));
895         sinfo->sinfo_ppid = cpu_to_le32(dlm_our_nodeid());
896         outmessage.msg_controllen = cmsg->cmsg_len;
897
898         ret = kernel_sendmsg(base_con->sock, &outmessage, iov, 1, len);
899         if (ret < 0) {
900                 log_print("Send first packet to node %d failed: %d",
901                           con->nodeid, ret);
902
903                 /* Try again later */
904                 clear_bit(CF_CONNECT_PENDING, &con->flags);
905                 clear_bit(CF_INIT_PENDING, &con->flags);
906         }
907         else {
908                 spin_lock(&con->writequeue_lock);
909                 e->offset += ret;
910                 e->len -= ret;
911
912                 if (e->len == 0 && e->users == 0) {
913                         list_del(&e->list);
914                         free_entry(e);
915                 }
916                 spin_unlock(&con->writequeue_lock);
917         }
918 }
919
920 /* Connect a new socket to its peer */
921 static void tcp_connect_to_sock(struct connection *con)
922 {
923         int result = -EHOSTUNREACH;
924         struct sockaddr_storage saddr, src_addr;
925         int addr_len;
926         struct socket *sock = NULL;
927         int one = 1;
928
929         if (con->nodeid == 0) {
930                 log_print("attempt to connect sock 0 foiled");
931                 return;
932         }
933
934         mutex_lock(&con->sock_mutex);
935         if (con->retries++ > MAX_CONNECT_RETRIES)
936                 goto out;
937
938         /* Some odd races can cause double-connects, ignore them */
939         if (con->sock) {
940                 result = 0;
941                 goto out;
942         }
943
944         /* Create a socket to communicate with */
945         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
946                                   IPPROTO_TCP, &sock);
947         if (result < 0)
948                 goto out_err;
949
950         memset(&saddr, 0, sizeof(saddr));
951         if (dlm_nodeid_to_addr(con->nodeid, &saddr))
952                 goto out_err;
953
954         sock->sk->sk_user_data = con;
955         con->rx_action = receive_from_sock;
956         con->connect_action = tcp_connect_to_sock;
957         add_sock(sock, con);
958
959         /* Bind to our cluster-known address connecting to avoid
960            routing problems */
961         memcpy(&src_addr, dlm_local_addr[0], sizeof(src_addr));
962         make_sockaddr(&src_addr, 0, &addr_len);
963         result = sock->ops->bind(sock, (struct sockaddr *) &src_addr,
964                                  addr_len);
965         if (result < 0) {
966                 log_print("could not bind for connect: %d", result);
967                 /* This *may* not indicate a critical error */
968         }
969
970         make_sockaddr(&saddr, dlm_config.ci_tcp_port, &addr_len);
971
972         log_print("connecting to %d", con->nodeid);
973
974         /* Turn off Nagle's algorithm */
975         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
976                           sizeof(one));
977
978         result =
979                 sock->ops->connect(sock, (struct sockaddr *)&saddr, addr_len,
980                                    O_NONBLOCK);
981         if (result == -EINPROGRESS)
982                 result = 0;
983         if (result == 0)
984                 goto out;
985
986 out_err:
987         if (con->sock) {
988                 sock_release(con->sock);
989                 con->sock = NULL;
990         } else if (sock) {
991                 sock_release(sock);
992         }
993         /*
994          * Some errors are fatal and this list might need adjusting. For other
995          * errors we try again until the max number of retries is reached.
996          */
997         if (result != -EHOSTUNREACH && result != -ENETUNREACH &&
998             result != -ENETDOWN && result != -EINVAL
999             && result != -EPROTONOSUPPORT) {
1000                 lowcomms_connect_sock(con);
1001                 result = 0;
1002         }
1003 out:
1004         mutex_unlock(&con->sock_mutex);
1005         return;
1006 }
1007
1008 static struct socket *tcp_create_listen_sock(struct connection *con,
1009                                              struct sockaddr_storage *saddr)
1010 {
1011         struct socket *sock = NULL;
1012         int result = 0;
1013         int one = 1;
1014         int addr_len;
1015
1016         if (dlm_local_addr[0]->ss_family == AF_INET)
1017                 addr_len = sizeof(struct sockaddr_in);
1018         else
1019                 addr_len = sizeof(struct sockaddr_in6);
1020
1021         /* Create a socket to communicate with */
1022         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_STREAM,
1023                                   IPPROTO_TCP, &sock);
1024         if (result < 0) {
1025                 log_print("Can't create listening comms socket");
1026                 goto create_out;
1027         }
1028
1029         /* Turn off Nagle's algorithm */
1030         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (char *)&one,
1031                           sizeof(one));
1032
1033         result = kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR,
1034                                    (char *)&one, sizeof(one));
1035
1036         if (result < 0) {
1037                 log_print("Failed to set SO_REUSEADDR on socket: %d", result);
1038         }
1039         sock->sk->sk_user_data = con;
1040         con->rx_action = tcp_accept_from_sock;
1041         con->connect_action = tcp_connect_to_sock;
1042         con->sock = sock;
1043
1044         /* Bind to our port */
1045         make_sockaddr(saddr, dlm_config.ci_tcp_port, &addr_len);
1046         result = sock->ops->bind(sock, (struct sockaddr *) saddr, addr_len);
1047         if (result < 0) {
1048                 log_print("Can't bind to port %d", dlm_config.ci_tcp_port);
1049                 sock_release(sock);
1050                 sock = NULL;
1051                 con->sock = NULL;
1052                 goto create_out;
1053         }
1054         result = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
1055                                  (char *)&one, sizeof(one));
1056         if (result < 0) {
1057                 log_print("Set keepalive failed: %d", result);
1058         }
1059
1060         result = sock->ops->listen(sock, 5);
1061         if (result < 0) {
1062                 log_print("Can't listen on port %d", dlm_config.ci_tcp_port);
1063                 sock_release(sock);
1064                 sock = NULL;
1065                 goto create_out;
1066         }
1067
1068 create_out:
1069         return sock;
1070 }
1071
1072 /* Get local addresses */
1073 static void init_local(void)
1074 {
1075         struct sockaddr_storage sas, *addr;
1076         int i;
1077
1078         dlm_local_count = 0;
1079         for (i = 0; i < DLM_MAX_ADDR_COUNT; i++) {
1080                 if (dlm_our_addr(&sas, i))
1081                         break;
1082
1083                 addr = kmalloc(sizeof(*addr), GFP_NOFS);
1084                 if (!addr)
1085                         break;
1086                 memcpy(addr, &sas, sizeof(*addr));
1087                 dlm_local_addr[dlm_local_count++] = addr;
1088         }
1089 }
1090
1091 /* Bind to an IP address. SCTP allows multiple address so it can do
1092    multi-homing */
1093 static int add_sctp_bind_addr(struct connection *sctp_con,
1094                               struct sockaddr_storage *addr,
1095                               int addr_len, int num)
1096 {
1097         int result = 0;
1098
1099         if (num == 1)
1100                 result = kernel_bind(sctp_con->sock,
1101                                      (struct sockaddr *) addr,
1102                                      addr_len);
1103         else
1104                 result = kernel_setsockopt(sctp_con->sock, SOL_SCTP,
1105                                            SCTP_SOCKOPT_BINDX_ADD,
1106                                            (char *)addr, addr_len);
1107
1108         if (result < 0)
1109                 log_print("Can't bind to port %d addr number %d",
1110                           dlm_config.ci_tcp_port, num);
1111
1112         return result;
1113 }
1114
1115 /* Initialise SCTP socket and bind to all interfaces */
1116 static int sctp_listen_for_all(void)
1117 {
1118         struct socket *sock = NULL;
1119         struct sockaddr_storage localaddr;
1120         struct sctp_event_subscribe subscribe;
1121         int result = -EINVAL, num = 1, i, addr_len;
1122         struct connection *con = nodeid2con(0, GFP_NOFS);
1123         int bufsize = NEEDED_RMEM;
1124
1125         if (!con)
1126                 return -ENOMEM;
1127
1128         log_print("Using SCTP for communications");
1129
1130         result = sock_create_kern(dlm_local_addr[0]->ss_family, SOCK_SEQPACKET,
1131                                   IPPROTO_SCTP, &sock);
1132         if (result < 0) {
1133                 log_print("Can't create comms socket, check SCTP is loaded");
1134                 goto out;
1135         }
1136
1137         /* Listen for events */
1138         memset(&subscribe, 0, sizeof(subscribe));
1139         subscribe.sctp_data_io_event = 1;
1140         subscribe.sctp_association_event = 1;
1141         subscribe.sctp_send_failure_event = 1;
1142         subscribe.sctp_shutdown_event = 1;
1143         subscribe.sctp_partial_delivery_event = 1;
1144
1145         result = kernel_setsockopt(sock, SOL_SOCKET, SO_RCVBUFFORCE,
1146                                  (char *)&bufsize, sizeof(bufsize));
1147         if (result)
1148                 log_print("Error increasing buffer space on socket %d", result);
1149
1150         result = kernel_setsockopt(sock, SOL_SCTP, SCTP_EVENTS,
1151                                    (char *)&subscribe, sizeof(subscribe));
1152         if (result < 0) {
1153                 log_print("Failed to set SCTP_EVENTS on socket: result=%d",
1154                           result);
1155                 goto create_delsock;
1156         }
1157
1158         /* Init con struct */
1159         sock->sk->sk_user_data = con;
1160         con->sock = sock;
1161         con->sock->sk->sk_data_ready = lowcomms_data_ready;
1162         con->rx_action = receive_from_sock;
1163         con->connect_action = sctp_init_assoc;
1164
1165         /* Bind to all interfaces. */
1166         for (i = 0; i < dlm_local_count; i++) {
1167                 memcpy(&localaddr, dlm_local_addr[i], sizeof(localaddr));
1168                 make_sockaddr(&localaddr, dlm_config.ci_tcp_port, &addr_len);
1169
1170                 result = add_sctp_bind_addr(con, &localaddr, addr_len, num);
1171                 if (result)
1172                         goto create_delsock;
1173                 ++num;
1174         }
1175
1176         result = sock->ops->listen(sock, 5);
1177         if (result < 0) {
1178                 log_print("Can't set socket listening");
1179                 goto create_delsock;
1180         }
1181
1182         return 0;
1183
1184 create_delsock:
1185         sock_release(sock);
1186         con->sock = NULL;
1187 out:
1188         return result;
1189 }
1190
1191 static int tcp_listen_for_all(void)
1192 {
1193         struct socket *sock = NULL;
1194         struct connection *con = nodeid2con(0, GFP_NOFS);
1195         int result = -EINVAL;
1196
1197         if (!con)
1198                 return -ENOMEM;
1199
1200         /* We don't support multi-homed hosts */
1201         if (dlm_local_addr[1] != NULL) {
1202                 log_print("TCP protocol can't handle multi-homed hosts, "
1203                           "try SCTP");
1204                 return -EINVAL;
1205         }
1206
1207         log_print("Using TCP for communications");
1208
1209         sock = tcp_create_listen_sock(con, dlm_local_addr[0]);
1210         if (sock) {
1211                 add_sock(sock, con);
1212                 result = 0;
1213         }
1214         else {
1215                 result = -EADDRINUSE;
1216         }
1217
1218         return result;
1219 }
1220
1221
1222
1223 static struct writequeue_entry *new_writequeue_entry(struct connection *con,
1224                                                      gfp_t allocation)
1225 {
1226         struct writequeue_entry *entry;
1227
1228         entry = kmalloc(sizeof(struct writequeue_entry), allocation);
1229         if (!entry)
1230                 return NULL;
1231
1232         entry->page = alloc_page(allocation);
1233         if (!entry->page) {
1234                 kfree(entry);
1235                 return NULL;
1236         }
1237
1238         entry->offset = 0;
1239         entry->len = 0;
1240         entry->end = 0;
1241         entry->users = 0;
1242         entry->con = con;
1243
1244         return entry;
1245 }
1246
1247 void *dlm_lowcomms_get_buffer(int nodeid, int len, gfp_t allocation, char **ppc)
1248 {
1249         struct connection *con;
1250         struct writequeue_entry *e;
1251         int offset = 0;
1252         int users = 0;
1253
1254         con = nodeid2con(nodeid, allocation);
1255         if (!con)
1256                 return NULL;
1257
1258         spin_lock(&con->writequeue_lock);
1259         e = list_entry(con->writequeue.prev, struct writequeue_entry, list);
1260         if ((&e->list == &con->writequeue) ||
1261             (PAGE_CACHE_SIZE - e->end < len)) {
1262                 e = NULL;
1263         } else {
1264                 offset = e->end;
1265                 e->end += len;
1266                 users = e->users++;
1267         }
1268         spin_unlock(&con->writequeue_lock);
1269
1270         if (e) {
1271         got_one:
1272                 *ppc = page_address(e->page) + offset;
1273                 return e;
1274         }
1275
1276         e = new_writequeue_entry(con, allocation);
1277         if (e) {
1278                 spin_lock(&con->writequeue_lock);
1279                 offset = e->end;
1280                 e->end += len;
1281                 users = e->users++;
1282                 list_add_tail(&e->list, &con->writequeue);
1283                 spin_unlock(&con->writequeue_lock);
1284                 goto got_one;
1285         }
1286         return NULL;
1287 }
1288
1289 void dlm_lowcomms_commit_buffer(void *mh)
1290 {
1291         struct writequeue_entry *e = (struct writequeue_entry *)mh;
1292         struct connection *con = e->con;
1293         int users;
1294
1295         spin_lock(&con->writequeue_lock);
1296         users = --e->users;
1297         if (users)
1298                 goto out;
1299         e->len = e->end - e->offset;
1300         spin_unlock(&con->writequeue_lock);
1301
1302         if (!test_and_set_bit(CF_WRITE_PENDING, &con->flags)) {
1303                 queue_work(send_workqueue, &con->swork);
1304         }
1305         return;
1306
1307 out:
1308         spin_unlock(&con->writequeue_lock);
1309         return;
1310 }
1311
1312 /* Send a message */
1313 static void send_to_sock(struct connection *con)
1314 {
1315         int ret = 0;
1316         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
1317         struct writequeue_entry *e;
1318         int len, offset;
1319         int count = 0;
1320
1321         mutex_lock(&con->sock_mutex);
1322         if (con->sock == NULL)
1323                 goto out_connect;
1324
1325         spin_lock(&con->writequeue_lock);
1326         for (;;) {
1327                 e = list_entry(con->writequeue.next, struct writequeue_entry,
1328                                list);
1329                 if ((struct list_head *) e == &con->writequeue)
1330                         break;
1331
1332                 len = e->len;
1333                 offset = e->offset;
1334                 BUG_ON(len == 0 && e->users == 0);
1335                 spin_unlock(&con->writequeue_lock);
1336
1337                 ret = 0;
1338                 if (len) {
1339                         ret = kernel_sendpage(con->sock, e->page, offset, len,
1340                                               msg_flags);
1341                         if (ret == -EAGAIN || ret == 0) {
1342                                 if (ret == -EAGAIN &&
1343                                     test_bit(SOCK_ASYNC_NOSPACE, &con->sock->flags) &&
1344                                     !test_and_set_bit(CF_APP_LIMITED, &con->flags)) {
1345                                         /* Notify TCP that we're limited by the
1346                                          * application window size.
1347                                          */
1348                                         set_bit(SOCK_NOSPACE, &con->sock->flags);
1349                                         con->sock->sk->sk_write_pending++;
1350                                 }
1351                                 cond_resched();
1352                                 goto out;
1353                         }
1354                         if (ret <= 0)
1355                                 goto send_error;
1356                 }
1357
1358                 /* Don't starve people filling buffers */
1359                 if (++count >= MAX_SEND_MSG_COUNT) {
1360                         cond_resched();
1361                         count = 0;
1362                 }
1363
1364                 spin_lock(&con->writequeue_lock);
1365                 e->offset += ret;
1366                 e->len -= ret;
1367
1368                 if (e->len == 0 && e->users == 0) {
1369                         list_del(&e->list);
1370                         free_entry(e);
1371                         continue;
1372                 }
1373         }
1374         spin_unlock(&con->writequeue_lock);
1375 out:
1376         mutex_unlock(&con->sock_mutex);
1377         return;
1378
1379 send_error:
1380         mutex_unlock(&con->sock_mutex);
1381         close_connection(con, false);
1382         lowcomms_connect_sock(con);
1383         return;
1384
1385 out_connect:
1386         mutex_unlock(&con->sock_mutex);
1387         if (!test_bit(CF_INIT_PENDING, &con->flags))
1388                 lowcomms_connect_sock(con);
1389         return;
1390 }
1391
1392 static void clean_one_writequeue(struct connection *con)
1393 {
1394         struct writequeue_entry *e, *safe;
1395
1396         spin_lock(&con->writequeue_lock);
1397         list_for_each_entry_safe(e, safe, &con->writequeue, list) {
1398                 list_del(&e->list);
1399                 free_entry(e);
1400         }
1401         spin_unlock(&con->writequeue_lock);
1402 }
1403
1404 /* Called from recovery when it knows that a node has
1405    left the cluster */
1406 int dlm_lowcomms_close(int nodeid)
1407 {
1408         struct connection *con;
1409
1410         log_print("closing connection to node %d", nodeid);
1411         con = nodeid2con(nodeid, 0);
1412         if (con) {
1413                 clear_bit(CF_CONNECT_PENDING, &con->flags);
1414                 clear_bit(CF_WRITE_PENDING, &con->flags);
1415                 set_bit(CF_CLOSE, &con->flags);
1416                 if (cancel_work_sync(&con->swork))
1417                         log_print("canceled swork for node %d", nodeid);
1418                 if (cancel_work_sync(&con->rwork))
1419                         log_print("canceled rwork for node %d", nodeid);
1420                 clean_one_writequeue(con);
1421                 close_connection(con, true);
1422         }
1423         return 0;
1424 }
1425
1426 /* Receive workqueue function */
1427 static void process_recv_sockets(struct work_struct *work)
1428 {
1429         struct connection *con = container_of(work, struct connection, rwork);
1430         int err;
1431
1432         clear_bit(CF_READ_PENDING, &con->flags);
1433         do {
1434                 err = con->rx_action(con);
1435         } while (!err);
1436 }
1437
1438 /* Send workqueue function */
1439 static void process_send_sockets(struct work_struct *work)
1440 {
1441         struct connection *con = container_of(work, struct connection, swork);
1442
1443         if (test_and_clear_bit(CF_CONNECT_PENDING, &con->flags)) {
1444                 con->connect_action(con);
1445                 set_bit(CF_WRITE_PENDING, &con->flags);
1446         }
1447         if (test_and_clear_bit(CF_WRITE_PENDING, &con->flags))
1448                 send_to_sock(con);
1449 }
1450
1451
1452 /* Discard all entries on the write queues */
1453 static void clean_writequeues(void)
1454 {
1455         foreach_conn(clean_one_writequeue);
1456 }
1457
1458 static void work_stop(void)
1459 {
1460         destroy_workqueue(recv_workqueue);
1461         destroy_workqueue(send_workqueue);
1462 }
1463
1464 static int work_start(void)
1465 {
1466         recv_workqueue = alloc_workqueue("dlm_recv",
1467                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1468         if (!recv_workqueue) {
1469                 log_print("can't start dlm_recv");
1470                 return -ENOMEM;
1471         }
1472
1473         send_workqueue = alloc_workqueue("dlm_send",
1474                                          WQ_UNBOUND | WQ_MEM_RECLAIM, 1);
1475         if (!send_workqueue) {
1476                 log_print("can't start dlm_send");
1477                 destroy_workqueue(recv_workqueue);
1478                 return -ENOMEM;
1479         }
1480
1481         return 0;
1482 }
1483
1484 static void stop_conn(struct connection *con)
1485 {
1486         con->flags |= 0x0F;
1487         if (con->sock && con->sock->sk)
1488                 con->sock->sk->sk_user_data = NULL;
1489 }
1490
1491 static void free_conn(struct connection *con)
1492 {
1493         close_connection(con, true);
1494         if (con->othercon)
1495                 kmem_cache_free(con_cache, con->othercon);
1496         hlist_del(&con->list);
1497         kmem_cache_free(con_cache, con);
1498 }
1499
1500 void dlm_lowcomms_stop(void)
1501 {
1502         /* Set all the flags to prevent any
1503            socket activity.
1504         */
1505         mutex_lock(&connections_lock);
1506         foreach_conn(stop_conn);
1507         mutex_unlock(&connections_lock);
1508
1509         work_stop();
1510
1511         mutex_lock(&connections_lock);
1512         clean_writequeues();
1513
1514         foreach_conn(free_conn);
1515
1516         mutex_unlock(&connections_lock);
1517         kmem_cache_destroy(con_cache);
1518 }
1519
1520 int dlm_lowcomms_start(void)
1521 {
1522         int error = -EINVAL;
1523         struct connection *con;
1524         int i;
1525
1526         for (i = 0; i < CONN_HASH_SIZE; i++)
1527                 INIT_HLIST_HEAD(&connection_hash[i]);
1528
1529         init_local();
1530         if (!dlm_local_count) {
1531                 error = -ENOTCONN;
1532                 log_print("no local IP address has been set");
1533                 goto out;
1534         }
1535
1536         error = -ENOMEM;
1537         con_cache = kmem_cache_create("dlm_conn", sizeof(struct connection),
1538                                       __alignof__(struct connection), 0,
1539                                       NULL);
1540         if (!con_cache)
1541                 goto out;
1542
1543         /* Start listening */
1544         if (dlm_config.ci_protocol == 0)
1545                 error = tcp_listen_for_all();
1546         else
1547                 error = sctp_listen_for_all();
1548         if (error)
1549                 goto fail_unlisten;
1550
1551         error = work_start();
1552         if (error)
1553                 goto fail_unlisten;
1554
1555         return 0;
1556
1557 fail_unlisten:
1558         con = nodeid2con(0,0);
1559         if (con) {
1560                 close_connection(con, false);
1561                 kmem_cache_free(con_cache, con);
1562         }
1563         kmem_cache_destroy(con_cache);
1564
1565 out:
1566         return error;
1567 }